Comparative Efficacy of Feline Leukemia Virus (FeLV) Inactivated Whole-Virus Vaccine and Canarypox Virus-Vectored Vaccine during Virulent FeLV Challenge and Immunosuppression.

Science.gov (United States)

Patel, M; Carritt, K; Lane, J; Jayappa, H; Stahl, M; Bourgeois, M

2015-07-01

Four vaccines for feline leukemia virus (FeLV) are available in the United States. This study's purpose was to compare the efficacy of Nobivac feline 2-FeLV (an inactivated, adjuvanted whole-virus vaccine) and PureVax recombinant FeLV (a live, canarypox virus-vectored vaccine) following FeLV challenge. Cats were vaccinated at 9 and 12 weeks with Nobivac feline 2-FeLV (group A, n = 11) or PureVax recombinant FeLV (group B, n = 10). Group C (n = 11) comprised unvaccinated controls. At 3 months postvaccination, cats were immunosuppressed and challenged with FeLV-A/61E. The outcomes measured were persistent antigenemia at 12 weeks postchallenge (PC) and proviral DNA and viral RNA at 3 to 9 weeks PC. Persistent antigenemia was observed in 0 of 11 cats in group A, 5 of 10 cats in group B, and 10 of 11 cats in group C. Group A was significantly protected compared to those in groups B (P 0.063). The preventable fraction was 100% for group A and 45% for group B. At 9 weeks PC, proviral DNA and viral RNA were detected 1 of 11 cats in group A, 6 of 10 cats in group B, and 9 of 11 cats in group C. Nucleic acid loads were significantly lower in group A than in group C (P feline 2-FeLV-vaccinated cats were fully protected against persistent antigenemia and had significantly smaller amounts of proviral DNA and plasma viral RNA loads than PureVax recombinant FeLV-vaccinated cats and unvaccinated controls. Copyright © 2015, Patel et al.

Studies on the synthesis of isotopes of superheavy element Lv (Z = 116)

Energy Technology Data Exchange (ETDEWEB)

Santhosh, K.P.; Safoora, V. [Kannur University, School of Pure and Applied Physics, Payyanur (India)

2017-11-15

The probable projectile-target combinations for the synthesis of superheavy nucleus {sup 296}Lv found in the cold valley of {sup 296}Lv have been identified by studying the interaction barrier of the colliding nuclei, probability of compound nucleus formation, P{sub CN}, and survival probability W{sub sur}. At energies near and above the Coulomb barrier, the capture, fusion and evaporation residue (ER) cross sections for the probable combinations for the hot and cold fusion reactions are systematically investigated. By considering intensities of the projectile beams, availabilities of the targets and half lives of the colliding nuclei, the combination {sup 48}Ca + {sup 248}Cm is found to be the most probable projectile-target pair for the synthesis of {sup 296}Lv. The calculated maximum value of 2n, 3n, 4n and 5n channel cross section for the reaction {sup 48}Ca + {sup 248}Cm are 0.599 pb, 5.957 pb, 4.805 pb, and 0.065 pb, respectively. Moreover, the production cross sections for the synthesis of isotopes {sup 291-295,298}Lv using {sup 48}Ca projectile on {sup 243-247,250}Cm targets are calculated. Among these reactions, the reactions {sup 48}Ca + {sup 247}Cm → {sup 295}Lv and {sup 48}Ca + {sup 250}Cm → {sup 298}Lv have maximum production cross section in 3n (10.697 pb) and 4n (12.006 pb) channel, respectively. Our studies on the SHE Lv using the combinations {sup 48}Ca + {sup 245}Cm → {sup 293}Lv and {sup 48}Ca + {sup 248}Cm → {sup 296}Lv are compared with available experimental data and with other theoretical studies. Our studies are in agreement with experimental data and we hope that these studies will be a guide for the future experiments to synthesize the isotopes of Lv. (orig.)

Comparative proteome approach demonstrates that platelet-derived growth factor C and D efficiently induce proliferation while maintaining multipotency of hMSCs

Energy Technology Data Exchange (ETDEWEB)

Sotoca, Ana M., E-mail: a.sotoca@science.ru.nl [Department of Cell and Applied Biology, Radboud University, Heijendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Roelofs-Hendriks, Jose [Department of Cell and Applied Biology, Radboud University, Heijendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Boeren, Sjef [Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen (Netherlands); Kraan, Peter M. van der [Department of Rheumatology Research and Advanced Therapeutics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Vervoort, Jacques [Laboratory of Biochemistry, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen (Netherlands); Zoelen, Everardus J.J. van; Piek, Ester [Department of Cell and Applied Biology, Radboud University, Heijendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

2013-10-15

This is the first study that comprehensively describes the effects of the platelet-derived growth factor (PDGF) isoforms C and D during in vitro expansion of human mesenchymal stem cells (hMSCs). Our results show that PDGFs can enhance proliferation of hMSCs without affecting their multipotency. It is of great value to culture and expand hMSCs in a safe and effective manner without losing their multipotency for manipulation and further development of cell-based therapies. Moreover, differential effects of PDGF isoforms have been observed on lineage-specific differentiation induced by BMP2 and Vitamin D3. Based on label-free LC-based quantitative proteomics approach we have furthermore identified specific pathways induced by PDGFs during the proliferation process, showing the importance of bioinformatics tools to study cell function. - Highlights: • PDGFs (C and D) significantly increased the number of multipotent undifferentiated hMSCs. • Enhanced proliferation did not impair the ability to undergo lineage-specific differentiation. • Proteomic analysis confirmed the overall signatures of the ‘intact’ cells.

Tilapia lake virus (TiLV): Literature review

OpenAIRE

Jansen, Mona Dverdal; Mohan, Chadag Vishnumurthy

2017-01-01

Tilapia lake virus (TiLV) is an emerging infectious agent that has recently been identified in diseased tilapia on three continents. At the time of writing, scientific publications have reported TiLV in samples collected from Colombia, Ecuador, Egypt, Israel and Thailand. While the link between TiLV and disease outbreaks in Israel and Thailand are well documented, further investigations are being undertaken to determine the significance of TiLV in the other countries. Israel and Taiwan Provin...

Application of MV/LV Transformers with OLTC for Increasing the PV Hosting Capacity Of LV Grids

DEFF Research Database (Denmark)

Hashemi Toghroljerdi, Seyedmostafa; Heckmann, Wolfram; Geibel, Dominik

2015-01-01

The increased use of grid connected photovoltaic (PV) systems in low voltage (LV) grids also raises concern regarding the effects of these new generation units on the grid operation. Overvoltage in LV grids during high PV generation periods is one of the well-known effects caused by PV systems......) and the reactive power absorption by PV inverters, are investigated using field test results and simulations performed on the mentioned LV grid. The results show that the application of OLTC can effectively increase the PV hosting capacity of the grid......., which potentially can decrease the PV hosting capacity of electric grids. This paper presents the applications of medium voltage to low voltage (MV/LV) transformers with on-load tap changers (OLTCs) to prevent overvoltage in high PV penetration conditions. Autonomous methods for controlling...

Fabrication and Characterization of Single-Aperture 3.5-MHz BNT-Based Ultrasonic Transducer for Therapeutic Application.

Science.gov (United States)

Taghaddos, Elaheh; Ma, T; Zhong, Hui; Zhou, Qifa; Wan, M X; Safari, Ahmad

2018-04-01

This paper discusses the fabrication and characterization of 3.5-MHz single-element transducers for therapeutic applications in which the active elements are made of hard lead-free BNT-based and hard commercial PZT (PZT-841) piezoceramics. Composition of (BiNa 0.88 K 0.08 Li 0.04 ) 0.5 (Ti 0.985 Mn 0.015 )O 3 (BNKLT88-1.5Mn) was used to develop lead-free piezoelectric ceramic. Mn-doped samples exhibited high mechanical quality factor ( ) of 970, thickness coupling coefficient ( ) of 0.48, a dielectric constant ( ) of 310 (at 1 kHz), depolarization temperature ( ) of 200 °C, and coercive field ( ) of 52.5 kV/cm. Two different unfocused single-element transducers using BNKLT88-1.5Mn and PZT-841 with the same center frequency of 3.5 MHz and similar aperture size of 10.7 and 10.5 mm were fabricated. Pulse-echo response, acoustic frequency spectrum, acoustic pressure field, and acoustic intensity field of transducers were characterized. The BNT-based transducer shows linear response up to the peak-to-peak voltage of 105 V in which the maximum rarefactional acoustic pressure of 1.1 MPa, and acoustic intensity of 43 W/cm 2 were achieved. Natural focal point of this transducer was at 60 mm from the surface of the transducer.

A targeted mutation within the feline leukemia virus (FeLV) envelope protein immunosuppressive domain to improve a canarypox virus-vectored FeLV vaccine.

Science.gov (United States)

Schlecht-Louf, Géraldine; Mangeney, Marianne; El-Garch, Hanane; Lacombe, Valérie; Poulet, Hervé; Heidmann, Thierry

2014-01-01

We previously delineated a highly conserved immunosuppressive (IS) domain within murine and primate retroviral envelope proteins that is critical for virus propagation in vivo. The envelope-mediated immunosuppression was assessed by the ability of the proteins, when expressed by allogeneic tumor cells normally rejected by engrafted mice, to allow these cells to escape, at least transiently, immune rejection. Using this approach, we identified key residues whose mutation (i) specifically abolishes immunosuppressive activity without affecting the "mechanical" function of the envelope protein and (ii) significantly enhances humoral and cellular immune responses elicited against the virus. The objective of this work was to study the immunosuppressive activity of the envelope protein (p15E) of feline leukemia virus (FeLV) and evaluate the effect of its abolition on the efficacy of a vaccine against FeLV. Here we demonstrate that the FeLV envelope protein is immunosuppressive in vivo and that this immunosuppressive activity can be "switched off" by targeted mutation of a specific amino acid. As a result of the introduction of the mutated envelope sequence into a previously well characterized canarypox virus-vectored vaccine (ALVAC-FeLV), the frequency of vaccine-induced FeLV-specific gamma interferon (IFN-γ)-producing cells was increased, whereas conversely, the frequency of vaccine-induced FeLV-specific interleukin-10 (IL-10)-producing cells was reduced. This shift in the IFN-γ/IL-10 response was associated with a higher efficacy of ALVAC-FeLV against FeLV infection. This study demonstrates that FeLV p15E is immunosuppressive in vivo, that the immunosuppressive domain of p15E can modulate the FeLV-specific immune response, and that the efficacy of FeLV vaccines can be enhanced by inhibiting the immunosuppressive activity of the IS domain through an appropriate mutation.

Assessment of the LV-S2 & LV-S3 Stack Sampling Probe Locations for Compliance with ANSI/HPS N13.1-1999

Energy Technology Data Exchange (ETDEWEB)

Glissmeyer, John A.; Antonio, Ernest J.; Flaherty, Julia E.; Amidan, Brett G.

2014-09-30

This document reports on a series of tests conducted to assess the proposed air sampling locations for the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Group 1-2A exhaust stacks with respect to the applicable criteria regarding the placement of an air sampling probe. The LV-C2, LV-S2, and LV-S3 exhaust stacks were tested together as a group (Test Group 1-2A). This report only covers the results of LV-S2 and LV-S3; LV-C2 will be reported on separately. Federal regulations1 require that a sampling probe be located in the exhaust stack according to the criteria established by the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities. 2 These criteria address the capability of the sampling probe to extract a sample that represents the effluent stream.

Mast cell stabilization decreases cardiomyocyte and LV function in dogs with isolated mitral regurgitation.

Science.gov (United States)

Pat, Betty; Killingsworth, Cheryl; Chen, Yuanwen; Gladden, James D; Walcott, Greg; Powell, Pamela C; Denney, Thomas; Gupta, Himanshu; Desai, Ravi; Tillson, Michael; Dillon, A Ray; Dell'italia, Louis J

2010-09-01

Mast cells are increased in isolated mitral regurgitation (MR) in the dog and may mediate extracellular matrix loss and left ventricular (LV) dilatation. We tested the hypothesis that mast cell stabilization would attenuate LV remodeling and improve function in the MR dog. MR was induced in adult dogs randomized to no treatment (MR, n = 5) or to the mast cell stabilizer, ketotifen (MR + MCS, n = 4) for 4 months. LV hemodynamics were obtained at baseline and after 4 months of MR and magnetic resonance imaging (MRI) was performed at sacrifice. MRI-derived, serial, short-axis LV end-diastolic (ED) and end-systolic (ES) volumes, LVED volume/mass ratio, and LV 3-dimensional radius/wall thickness were increased in MR and MR + MCS dogs compared with normal dogs (n = 6) (P < .05). Interstitial collagen was decreased by 30% in both MR and MR + MCS versus normal dogs (P < .05). LV contractility by LV maximum time-varying elastance was significantly depressed in MR and MR + MCS dogs. Furthermore, cardiomyocyte fractional shortening was decreased in MR versus normal dogs and further depressed in MR + MCS dogs (P < .05). In vitro administration of ketotifen to normal cardiomyocytes also significantly decreased fractional shortening and calcium transients. Chronic mast cell stabilization did not attenuate eccentric LV remodeling or collagen loss in MR. However, MCS therapy had a detrimental effect on LV function because of a direct negative inotropic effect on cardiomyocyte function. Published by Elsevier Inc.

E/e' Ratio: An Index of LV Filling Pressures Revisited

Directory of Open Access Journals (Sweden)

Sherif F. Nagueh

2013-01-01

Full Text Available There is a clinical need for the assessment of cardiac function in patients who present with symptoms and signs of pulmonary and systemic congestion. Echocardiography has been utilized over the years to answer this question. It is possible to study left ventricular (LV systolic and diastolic function as well as pulmonary artery pressures and right ventricular function using this technique. With respect to LV diastolic function, an ideal assessment includes evaluation of LV relaxation and LV filling pressures. There are several parameters that when properly acquired and analyzed can predict the 2 fundamental aspects noted above of LV diastolic function. The mitral annulus early diastolic recoil velocity (e’ recorded by tissue Doppler imaging (TDI was introduced as an index of LV relaxation. Further, e’ velocity is combined with mitral peak velocity E to predict LV filling pressures1. I will discuss the supporting literature for the last statement and point to the limitations in its application.

The increase of NADH fluorescence lifetime is associated with the metabolic change during osteogenic differentiation of human mesenchymal stem cells (hMSCs)

Science.gov (United States)

Guo, Han Wen; Yu, Jia Sin; Hsu, Shu Han; Wei, Yau Huei; Lee, Oscar K.; Wang, Hsing Wen

2011-03-01

Fluorescence lifetime of NADH had been used as an optical marker for monitoring cellular metabolism. In our pervious studies, we have demonstrated that NADH lifetime of hMSCs increase gradually with time of osteogenic differentiation. In this study, we measured NADH lifetime of hMSCs from a different donor as well as the corresponding metabolic indices such as ATP level, oxygen consumption and lactate release. We also measure the quantity of Complex I, III, IV and V. The results show that during differentiation more oxygen consumed, higher ATP level expressed and less lactate released, and the increase of NADH lifetime was associated with ATP level. Higher expression of the total Complex protein was observed at 3 and 4 weeks after differentiation than controls. However, Complex I expression did not show significant correlation with the increase of NADH fluorescence lifetime. In summary, we demonstrated that the change of NADH lifetime was associated with the metabolic change during osteogenic differentiation of hMSCs. The increase of NADH lifetime was in part due to the increased Complex protein interaction in mitochondria after differentiation.

Feline immunodeficiency virus (FIV, feline leukaemia virus (FeLV and Leishmania sp. in domestic cats in the Midwest of Brazil

Directory of Open Access Journals (Sweden)

Daniella Poffo

Full Text Available ABSTRACT: This search aimed to investigate FIV and FeLV infections in domestic cats, analysing the epidemiological profile of the disease as well as additional infection with Leishmania sp. We evaluated 88 domestic cats for the presence of FIV, FeLV and Leishmania sp. infection. Eleven (12.5% cats were positive for FIV infection, four (4.5% were positive for FeLV, and two were co-infected. However, none was infected with Leishmania sp. The prevalence for FIV infection was higher than FeLV, and those observed in other regions, but no factor was associated with the infection by FIV and FeLV in this study.

Measles virus envelope pseudotyped lentiviral vectors transduce quiescent human HSCs at an efficiency without precedent.

Science.gov (United States)

Lévy, Camille; Amirache, Fouzia; Girard-Gagnepain, Anais; Frecha, Cecilia; Roman-Rodríguez, Francisco J; Bernadin, Ornellie; Costa, Caroline; Nègre, Didier; Gutierrez-Guerrero, Alejandra; Vranckx, Lenard S; Clerc, Isabelle; Taylor, Naomi; Thielecke, Lars; Cornils, Kerstin; Bueren, Juan A; Rio, Paula; Gijsbers, Rik; Cosset, François-Loïc; Verhoeyen, Els

2017-10-24

Hematopoietic stem cell (HSC)-based gene therapy trials are now moving toward the use of lentiviral vectors (LVs) with success. However, one challenge in the field remains: efficient transduction of HSCs without compromising their stem cell potential. Here we showed that measles virus glycoprotein-displaying LVs (hemagglutinin and fusion protein LVs [H/F-LVs]) were capable of transducing 100% of early-acting cytokine-stimulated human CD34 + (hCD34 + ) progenitor cells upon a single application. Strikingly, these H/F-LVs also allowed transduction of up to 70% of nonstimulated quiescent hCD34 + cells, whereas conventional vesicular stomatitis virus G (VSV-G)-LVs reached 5% at the most with H/F-LV entry occurring exclusively through the CD46 complement receptor. Importantly, reconstitution of NOD/SCIDγc -/- (NSG) mice with H/F-LV transduced prestimulated or resting hCD34 + cells confirmed these high transduction levels in all myeloid and lymphoid lineages. Remarkably, for resting CD34 + cells, secondary recipients exhibited increasing transduction levels of up to 100%, emphasizing that H/F-LVs efficiently gene-marked HSCs in the resting state. Because H/F-LVs promoted ex vivo gene modification of minimally manipulated CD34 + progenitors that maintained stemness, we assessed their applicability in Fanconi anemia, a bone marrow (BM) failure with chromosomal fragility. Notably, only H/F-LVs efficiently gene-corrected minimally stimulated hCD34 + cells in unfractionated BM from these patients. These H/F-LVs improved HSC gene delivery in the absence of cytokine stimulation while maintaining their stem cell potential. Thus, H/F-LVs will facilitate future clinical applications requiring HSC gene modification, including BM failure syndromes, for which treatment has been very challenging up to now.

L.V. switchgear - design and development

International Nuclear Information System (INIS)

Armes, D.S.; Brown, R.D.

1992-01-01

This work describes the methods employed in the design and development of L.V. switchgear to meet the prospective conditions and operational requirements imposed on equipment at sites of PWR power stations. The work concentrates on the aspects of design, manufacture, qualification work and quality assurance particular to the range of L.V. switchgear distribution boards manufactured by Laurence, Scott and Electromotors Ltd. for Sizewell B Power Station and contrasts this equipment with other equipment for conventional (i.e. non-nuclear) power station purposes. (Author)

Preliminary results of pre-operative 5-FU, low dose leucovorin (LV), and concurrent radiation therapy (RT) for resectable T3 rectal cancer

International Nuclear Information System (INIS)

Grann, Alison; Minsky, Bruce D.; Cohen, Alfred M.; Saltz, Leonard; Kelsen, David P.; Kemeny, Nancy; Ilson, David; Guillem, Jose G.; Paty, Philip B.; Bass, Joanne

1996-01-01

PURPOSE: We report the downstaging, acute toxicity, and preliminary local control and survival of pre-op 5-FU, low dose LV, and concurrent RT followed by post-op LV/5-FU for pts with clinically resectable, T3 rectal cancer. MATERIALS AND METHODS: A total of 32 pts (M:26, F:6) were prospectively treated from 12/91-8/95. Eligibility criteria included adequate hematologic indicies, primary adenocarcinoma limited to the pelvis, and T3 disease confirmed by transrectal ultrasound. Twenty five pts were considered clinically to require an APR on initial (pre-treatment) assessment by their operating surgeon. The median age was 56 (range: 24-80), and the median distance from the anal verge was 5.0cm (range: 3-9cm). Pts received 2 monthly cycles (bolus daily X 5) of LV (20mg/m2) and 5-FU (325mg/m2), beginning concurrently with day 1 of RT, followed by surgery 4-5 weeks later. RT included 4680 cGy to the pelvis followed by a boost to 5040 cGy. Post-operatively, pts received a median of 2 monthly cycles (range: 0-10 cycles) of LV (20 mg/m2) and 5-FU (425mg/m2). A toxicity assessment was performed at each visit using the NCI toxicity criteria modified for gastrointestinal toxicity. The median follow-up was 12 months (range: 3-48 months). All 32 patients were included in the analysis of toxicity, sphincter preservation, and downstaging. Analysis of patterns of failure and survival was limited to the 15 pts who had a minimum follow-up of 1yr or developed failure prior to 1 yr. For this subset the median follow-up was 24 months (range: 3-48 months). RESULTS: During the pre-op segment, individual grade 3+ acute toxicities were; diarrhea: 16%, bowel movements: 16%, leukopenia: 12%. The incidence of total toxicity was 25% ((8(32))). The median nadir counts were; WBC: 2.9 (range: 1.7-5.6), HGB: 12.4 (range: 7.1-15.0), and PLT (X1000): 161 (range: 113-237). The pathologic complete response rate was 9% ((3(32))). An additional 13% ((4(32))) had negative lymph nodes and 1-2 microscopic

LV function monitoring to discard functional abnormalities in athletes with altered ventricular re-polarization

International Nuclear Information System (INIS)

Flotats, A.; Camacho, V.; Mena, E.; Tembl, A.; Estorch, M.; Carrio, I.; Serra-Grima, R.; Borras, X.; Cinca, J.

2002-01-01

Aim: Marked ventricular re-polarization abnormalities (MRA) in athletes may suggest the presence of associated heart disease. Assessment of LV function during exercise may contribute to rule out heart disease and help to decide continuation of physical training. The aim of the study was to assess whether athletes with MRA show a particular response of LV function to exhausting exercise. Material and Methods: Thirty-nine male athletes underwent monitoring of LV function with a miniaturised radionuclide detector (VEST, Capintec, Inc.) during bicycle exhausting exercise. There were 22 athletes with MRA in the ECG at rest (negative T waves equal or more than 2mm in up to 3 ECG leads) and 17 with normal ECG. All were symptom free. Age and physical fitness were comparable in both groups. Clinical examination, ECG, exercise test and echocardiography were performed in all athletes. Results: In all cases LV wall thickness was that expected for highly conditioned sportsmen. Both groups of athletes attained a similar energy expenditure. During exercise, athletes with MRA showed a tendency to normalise re-polarization. There were no differences in heart rate, LV end-systolic volume, LVEF, cardiac output , and peak ejection and filling rates at rest, 50%, 75%, 85% and 100% of peak HR, nor at 2, 5 and 10 min of recovery between both groups of athletes. At rest stroke volume was lower in athletes with MRA (60% vs. 64%, p=0.044). There were also no differences in LV end-diastolic volume (EDV), except at peak HR, when EDV increased in athletes with normal ECG while it decreased in athletes with MRA (p=0.047). Conclusions: The presence of marked ventricular re-polarization abnormalities in athletes does not substantially affect exercise performance nor LV function and should not preclude physical training. The VEST is a useful means to assess LV function during exhausting upright bicycle exercise

Telomerase expression extends the proliferative life-span and maintains the osteogenic potential of human bone marrow stromal cells

DEFF Research Database (Denmark)

Simonsen, Janne Lytoft; Rosada, Cecilia; Serakinci, Nedime

2002-01-01

Human bone marrow stromal cells (hMSCs) were stably transduced by a retroviral vector containing the gene for the catalytic subunit of human telomerase (hTERT). Transduced cells (hMSC-TERTs) had telomerase activity, and the mean telomere length was increased as compared with that of control cells....... The transduced cells have now undergone more than 260 population doublings (PD) and continue to proliferate, whereas control cells underwent senescence-associated proliferation arrest after 26 PD. The cells maintained production of osteoblastic markers and differentiation potential during continuous subculturing......, did not form tumors, and had a normal karyotype. When implanted subcutaneously in immunodeficient mice, the transduced cells formed more bone than did normal cells. These results suggest that ectopic expression of telomerase in hMSCs prevents senescence-associated impairment of osteoblast functions....

Left Ventricle: Fully Automated Segmentation Based on Spatiotemporal Continuity and Myocardium Information in Cine Cardiac Magnetic Resonance Imaging (LV-FAST

Directory of Open Access Journals (Sweden)

Lijia Wang

2015-01-01

Full Text Available CMR quantification of LV chamber volumes typically and manually defines the basal-most LV, which adds processing time and user-dependence. This study developed an LV segmentation method that is fully automated based on the spatiotemporal continuity of the LV (LV-FAST. An iteratively decreasing threshold region growing approach was used first from the midventricle to the apex, until the LV area and shape discontinued, and then from midventricle to the base, until less than 50% of the myocardium circumference was observable. Region growth was constrained by LV spatiotemporal continuity to improve robustness of apical and basal segmentations. The LV-FAST method was compared with manual tracing on cardiac cine MRI data of 45 consecutive patients. Of the 45 patients, LV-FAST and manual selection identified the same apical slices at both ED and ES and the same basal slices at both ED and ES in 38, 38, 38, and 41 cases, respectively, and their measurements agreed within -1.6±8.7 mL, -1.4±7.8 mL, and 1.0±5.8% for EDV, ESV, and EF, respectively. LV-FAST allowed LV volume-time course quantitatively measured within 3 seconds on a standard desktop computer, which is fast and accurate for processing the cine volumetric cardiac MRI data, and enables LV filling course quantification over the cardiac cycle.

Seroprevalence of feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) in shelter cats on the island of Newfoundland, Canada.

Science.gov (United States)

Munro, Hannah J; Berghuis, Lesley; Lang, Andrew S; Rogers, Laura; Whitney, Hugh

2014-04-01

Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are retroviruses found within domestic and wild cat populations. These viruses cause severe illnesses that eventually lead to death. Housing cats communally for long periods of time makes shelters at high risk for virus transmission among cats. We tested 548 cats from 5 different sites across the island of Newfoundland for FIV and FeLV. The overall seroprevalence was 2.2% and 6.2% for FIV and FeLV, respectively. Two sites had significantly higher seroprevalence of FeLV infection than the other 3 sites. Analysis of sequences from the FeLV env gene (envelope gene) from 6 positive cats showed that 4 fell within the FeLV subtype-A, while 2 sequences were most closely related to FeLV subtype-B and endogenous feline leukemia virus (en FeLV). Varying seroprevalence and the variation in sequences at different sites demonstrate that some shelters are at greater risk of FeLV infections and recombination can occur at sites of high seroprevalence.

Seismic monitoring during acid stimulation of wells LV-4 and LV-13 at the Las Tres Virgenes geothermal field, BCS, Mexico; Monitoreo sismico durante la estimulacion acida de los pozos LV-4 y LV-13 del campo geotermico de Las Tres Virgenes, BCS, Mexico

Energy Technology Data Exchange (ETDEWEB)

Venegas Salgado, Saul; Arredondo Fragoso, Jesus; Ramirez Silva, German; Flores Armenta, Magaly; Ramirez Montes, Miguel [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: magaly.flores@cfe.gob.mx

2006-07-15

From September through December 2004 a seismic monitoring in the Las Tres Virgenes, BCS, geothermal field was carried out simultaneously with the acid stimulation of wells LV-4 and LV-13. The seismic network had four digital seismographs and recorded 174 local seismic events, 131 regional ones and many more volcanic signals at seismic station TV20 during the acid stimulation. Additionally, 37 seismic events were located, 22 of them inside the most important geothermal zone at depths between 0.4 and 4 km with typically low magnitudes (0.7 to 2.2 Md). Two relevant zones were determined: Zone A related to the El Volcan fault system and Zone B related to injection well LV-8. In Zone A the well-induction stage and the operation start of the wells LV-4 and LV-13 after acidification on October 30 and November 17, 2004, increased seismic activity to a maximum of 12 daily events in early December. When the two wells in Zone B were cooled before the acidification, the seismic events recorded there increased to a maximum of 6 daily events on October 2, and then decreased. Also in Zone B the seismic activity increased after well-induction and the start of well production once they were acidified, recording up to 11 daily events in late November. According to the seismic distribution, we may conclude that the most active fault systems are El Volcan and El Viejo. New proposals for well locations in the field are supported by these results. [Spanish] De septiembre a diciembre de 2004 se realizo un estudio de monitoreo sismico en el campo geotermico de Las Tres Virgenes, BCS, simultaneamente con las estimulaciones acidas de los pozos LV-4 y LV-13. Se utilizo una red sismica conformada por cuatro sismografos digitales, logrando registrar en la estacion sismica TV20 un total de 174 sismos locales, 131 sismos regionales y muchas mas senales de tipo volcanico, durante el periodo del monitoreo de la estimulacion acida. Ademas, se localizaron un total de 37 sismos, de los cuales 22 se

Inferring microbial interaction networks from metagenomic data using SgLV-EKF algorithm.

Science.gov (United States)

Alshawaqfeh, Mustafa; Serpedin, Erchin; Younes, Ahmad Bani

2017-03-27

Inferring the microbial interaction networks (MINs) and modeling their dynamics are critical in understanding the mechanisms of the bacterial ecosystem and designing antibiotic and/or probiotic therapies. Recently, several approaches were proposed to infer MINs using the generalized Lotka-Volterra (gLV) model. Main drawbacks of these models include the fact that these models only consider the measurement noise without taking into consideration the uncertainties in the underlying dynamics. Furthermore, inferring the MIN is characterized by the limited number of observations and nonlinearity in the regulatory mechanisms. Therefore, novel estimation techniques are needed to address these challenges. This work proposes SgLV-EKF: a stochastic gLV model that adopts the extended Kalman filter (EKF) algorithm to model the MIN dynamics. In particular, SgLV-EKF employs a stochastic modeling of the MIN by adding a noise term to the dynamical model to compensate for modeling uncertainties. This stochastic modeling is more realistic than the conventional gLV model which assumes that the MIN dynamics are perfectly governed by the gLV equations. After specifying the stochastic model structure, we propose the EKF to estimate the MIN. SgLV-EKF was compared with two similarity-based algorithms, one algorithm from the integral-based family and two regression-based algorithms, in terms of the achieved performance on two synthetic data-sets and two real data-sets. The first data-set models the randomness in measurement data, whereas, the second data-set incorporates uncertainties in the underlying dynamics. The real data-sets are provided by a recent study pertaining to an antibiotic-mediated Clostridium difficile infection. The experimental results demonstrate that SgLV-EKF outperforms the alternative methods in terms of robustness to measurement noise, modeling errors, and tracking the dynamics of the MIN. Performance analysis demonstrates that the proposed SgLV-EKF algorithm

Transducer handbook user's directory of electrical transducers

CERN Document Server

Boyle, H B

2013-01-01

When selecting or using a particular type of transducer or sensor, there are a number of factors which must be considered. The question is not only for what kind of measurement, but under what physical conditions, constraints of accuracy, and to meet which service requirements, is a transducer needed? This handbook is designed to meet the selection needs of anyone specifying or using transducers with an electrical output. Each transducer is described in an easy-to-use tabular format, giving all of the necessary data including operating principles, applications, range limits, errors, over-range protection, supply voltage requirements, sensitivities, cross sensitivities, temperature ranges and sensitivities and signal conditioning needs. The author has added notes that reflect his broad practical experience. Added to this is an extensive worldwide suppliers directory.

Relationship between echocardiographic LV mass and ECG based left ventricular voltages in an adolescent population: related or random?

Science.gov (United States)

Czosek, Richard J; Cnota, James F; Knilans, Timothy K; Pratt, Jesse; Guerrier, Karine; Anderson, Jeffrey B

2014-09-01

In attempts to detect diseases that may place adolescents at risk for sudden death, some have advocated for population-based screening. Controversy exists over electrocardiography (ECG) screening due to the lack of specificity, cost, and detrimental effects of false positive or extraneous outcomes. Analyze the relationship between precordial lead voltage on ECG and left ventricle (LV) mass by echocardiogram in adolescent athletes. Retrospective cohort analysis of a prospectively obtained population of self-identified adolescent athletes during sports screening with ECG and echocardiogram. Correlation between ECG LV voltages (R wave in V6 [RV6] and S wave in lead V1 [SV1]) was compared to echocardiogram-based measurements of left ventricular mass. Potential effects on ECG voltages by body anthropometrics, including weight, body mass index (BMI), and body surface area were analyzed, and ECG voltages indexed to BMI were compared to LV mass indices to analyze for improved correlation. A total of 659 adolescents enrolled in this study (64% male). The mean age was 15.4 years (14-18). The correlations between LV mass and RV6, SV1, and RV6 + SV1 were all less than 0.20. The false positive rate for abnormal voltages was relatively high (5.5%) but improved if abnormal voltages in both RV6 and SV1 were mandated simultaneously (0%). Indexing ECG voltages to BMI significantly improved correlation to LV mass, though false positive findings were increased (12.9%). There is poor correlation between ECG precordial voltages and echocardiographic LV mass. This relationship is modified by BMI. This finding may contribute to the poor ECG screening characteristics. ©2014 Wiley Periodicals, Inc.

Pressure transducers

International Nuclear Information System (INIS)

Gomes, A.V.

1975-01-01

Strain gauges pressure transducers types are presented. Models, characteristics and calibration procedures were also analysed. Initially, a theoretical study was accomplished to evaluate metallic alloys behavior on sensing elements manufacturing, and diaphragm was used as deflecting elements. Electrical models for potenciometric transducers were proposed at the beginning and subsequently comproved according our experiments. Concerning bridge transducers, existing models confirmed the conditions of linearity and sensitivity related to the electrical signal. All the work done was of help on the calibration field and pressure measurements employing unbounded strain gauge pressure transducers

lacZ transduced human breast cancer xenografts as an in vivo model for the study of invasion and metastasis

DEFF Research Database (Denmark)

Brünner, N; Thompson, E W; Spang-Thomsen, M

1992-01-01

in the animals by usual histological procedures would require extensive sectioning of the whole animal. To overcome this problem, we transduced human breast cancer cells with a replication-defective Moloney murine leukaemia retroviral vector (M-MuLV) containing both neoR (neomycin resistance) and lacZ genes...... but not the surrounding mouse tissue on either whole tissue blocks or histological sections. The staining procedure was highly sensitive, allowing detection of microfoci of human cancer cells, and quantitative estimation of the metastatic capacity of the cells. These results indicate that lacZ transduction of human...

Transducer-Mounting Fixture

Science.gov (United States)

Spiegel, Kirk W.

1990-01-01

Transducer-mounting fixture holds transducer securely against stud. Projects only slightly beyond stud after installation. Flanged transducer fits into fixture when hinged halves open. When halves reclosed, fixture tightened onto threaded stud until stud makes contact with transducer. Knurled area on fixture aids in tightening fixture on stud.

Integration of SPICE with TEK LV500 ASIC Design Verification System

Directory of Open Access Journals (Sweden)

A. Srivastava

1996-01-01

Full Text Available The present work involves integration of the simulation stage of design of a VLSI circuit and its testing stage. The SPICE simulator, TEK LV500 ASIC Design Verification System, and TekWaves, a test program generator for LV500, were integrated. A software interface in ‘C’ language in UNIX ‘solaris 1.x’ environment has been developed between SPICE and the testing tools (TekWAVES and LV500. The function of the software interface developed is multifold. It takes input from either SPICE2G.6 or SPICE 3e.1. The output generated by the interface software can be given as an input to either TekWAVES or LV500. A graphical user interface has also been developed with OPENWlNDOWS using Xview tool kit on SUN workstation. As an example, a two phase clock generator circuit has been considered and usefulness of the software demonstrated. The interface software could be easily linked with VLSI design such as MAGIC layout editor.

La piattaforma POS/LV di Applanix nelle applicazioni di laser scanner cinematico

OpenAIRE

Domenico Santarsiero

2008-01-01

The Applanix POS/LV platform in cinematic laser scanner applicationsOn the 11th of march the GEOmedia editorial unit had the pleasure of hosting a technical meeting dedicated to the Applanix LANDMark new Position and Orientation System for Land Vehicles (POS/LV)field test. The meeting, which is part of an italian tour organized by Louis Nastro (Applanix Director of Land Products) and Terenzio Mariani (Sales manager for Italy), helped to test the functionalities of a complete POS/LV system equ...

3D additive-manufactured nanocomposite magnetic scaffolds: Effect of the application mode of a time-dependent magnetic field on hMSCs behavior

Directory of Open Access Journals (Sweden)

Ugo D'Amora

2017-09-01

The aim of the present study was to analyze the effect of the application mode of a time-dependent magnetic field on the behavior of human mesenchymal stem cells (hMSCs seeded on 3D additive-manufactured poly(ɛ-caprolactone/iron-doped hydroxyapatite (PCL/FeHA nanocomposite scaffolds.

The osteogenic response of undifferentiated human mesenchymal stem cells (hMSCs) to mechanical strain is inversely related to body mass index of the donor.

Science.gov (United States)

Friedl, Gerald; Windhager, Reinhard; Schmidt, Helena; Aigner, Reingard

2009-08-01

While the importance of physical factors in the maintenance and regeneration of bone tissue has been recognized for many years and the mechano-sensitivity of bone cells is well established, there is increasing evidence that body fat constitutes an independent risk factor for complications in bone fracture healing and aseptic loosening of implants. Although mechanical causes have been widely suggested, we hypothesized that the osteogenic mechano-response of human mesenchymal stem cells (hMSCs) may be altered in obese patients. We determined the phenotypic and genotypic response of undifferentiated hMSCs of 10 donors to cyclic tensile strain (CTS) under controlled in vitro conditions and analyzed the potential relationship relevant to the donor's anthropomorphometric and biochemical parameters related to donor's fat and bone metabolism. The osteogenic marker genes were all statistically significantly upregulated by CTS, which was accompanied by a significant increase in cell-based ALP activity. Linear correlation analysis revealed that there was a significant correlation between phenotypic CTS response and the body mass index of the donor (r = -0.91, p < 0.001) and phenotypic CTS response was also significantly related to leptin levels (r = -0.68) and estradiol levels (r = 0.67) within the bone marrow microenvironment of the donor. Such an upstream imprinting process mediated by factors tightly related to the donor's fat metabolism, which hampers the mechanosensitivity of hMSCs in obese patients, may be of pathogenetic relevance for the complications associated with obesity that are seen in orthopedic surgery.

Impact Study of Electric Vehicle (EV) Integration on Low Voltage (LV) Grids

DEFF Research Database (Denmark)

Wu, Qiuwei; Cha, Seung-Tae; Nielsen, Arne Hejde

2012-01-01

the single line diagram (SLD) of the LV grid. The demand profiles of end-users are determined by the end-user yearly consumption and avreaged demand profiles of different customer types in Denmark. Five charging scenarios have been tested using the developed LV grid. The first two charging scenarios are dumb....... The two charging power levels are 1 phase 16 A and 3 phase 16 A. The loading of the power components and voltage profile are analyzed to quantify the impact of the charging scenarios and charging power levels on LV grids....

Auto-positioning ultrasonic transducer system

Science.gov (United States)

Buchanan, Randy K. (Inventor)

2010-01-01

An ultrasonic transducer apparatus and process for determining the optimal transducer position for flow measurement along a conduit outer surface. The apparatus includes a transmitting transducer for transmitting an ultrasonic signal, said transducer affixed to a conduit outer surface; a guide rail attached to a receiving transducer for guiding movement of a receiving transducer along the conduit outer surface, wherein the receiving transducer receives an ultrasonic signal from the transmitting transducer and sends a signal to a data acquisition system; and a motor for moving the receiving transducer along the guide rail, wherein the motor is controlled by a controller. The method includes affixing a transmitting transducer to an outer surface of a conduit; moving a receiving transducer on the conduit outer surface, wherein the receiving transducer is moved along a guide rail by a motor; transmitting an ultrasonic signal from the transmitting transducer that is received by the receiving transducer; communicating the signal received by the receiving transducer to a data acquisition and control system; and repeating the moving, transmitting, and communicating along a length of the conduit.

Survey Observations to Study Chemical Evolution from High-mass Starless Cores to High-mass Protostellar Objects. I. HC3N and HC5N

Science.gov (United States)

Taniguchi, Kotomi; Saito, Masao; Sridharan, T. K.; Minamidani, Tetsuhiro

2018-02-01

We carried out survey observations of HC3N and HC5N in the 42‑45 GHz band toward 17 high-mass starless cores (HMSCs) and 35 high-mass protostellar objects (HMPOs) with the Nobeyama 45 m radio telescope. We have detected HC3N from 15 HMSCs and 28 HMPOs, and HC5N from 5 HMSCs and 14 HMPOs, respectively. The average values of the column density of HC3N are found to be (5.7+/- 0.7) × {10}12 and (1.03+/- 0.12)×{10}13 cm‑2 in HMSCs and HMPOs, respectively. The average values of the fractional abundance of HC3N are derived to be (6.6+/- 0.8)× {10}-11 and (3.6+/- 0.5)× {10}-11 in HMSCs and HMPOs, respectively. We find that the fractional abundance of HC3N decreases from HMSCs to HMPOs using the Kolmogorov–Smirnov test. On the other hand, its average value of the column density slightly increases from HMSCs to HMPOs. This may imply that HC3N is newly formed in dense gas in HMPO regions. We also investigate the relationship between the column density of HC3N in HMPOs and the luminosity-to-mass ratio (L/M), a physical evolutional indicator. The column density of HC3N tends to decrease with the increase of the L/M ratio, which suggests that HC3N is destroyed by the stellar activities.

Comparison of different current transducers used at JET within the range 5–100 kA for plasma control and monitoring

Energy Technology Data Exchange (ETDEWEB)

Salmon, R., E-mail: robjsalmon@gmail.com; Smith, P.; West, A.; Shaw, S.R.; Rendell, D.

2015-10-15

Highlights: • Zero-flux current transducers with sensory windings, Hall-effect DCCTs, Rogowski coils, shunt resistors and Faraday effect current transducers are reviewed. • All technologies have displayed good performance over 30 years of operation. • Faraday-effect current transducers have improved accuracy of the toroidal magnets current measurement on JET to 0.1%. • The improvement in accuracy has improved resolution on JET plasma kinetic profiles. - Abstract: The JET machine uses a variety of current transducers for control and protection of the plasma, the coils and their associated power supplies. This paper reviews the various measuring technologies, within the range 5–100 kA, used on JET to assist with the selection of high-current transducers for future plasma control/tokamak applications; these include Rogowski coils, coaxial shunts, Hall-effect transducers, zero-flux CTs and a Faraday-effect optical transducer. The paper considers reliability, accuracy and usability based on up to 30 years of operational experience of the transducers. Accuracy of the magnet current measurements is important in the control of tokamak plasmas and there has been considerable effort to improve it. Recently a Faraday-effect optical current sensor has been used to measure up to 67 kA in the Toroidal Field (TF) coil circuit. This measurement system has been calibrated at JET to verify its 0.1% accuracy. In addition, the data acquisition system for this measurement is automatically calibrated at the start of each JET pulse. The improved accuracy has been shown to enhance the spatial consistency of kinetic profiles at JET [1]. Due to its portability the JET project intends to employ the same Faraday-effect current transducer to calibrate other high current transducers by temporarily fitting it to other busbars, such as those in the Ohmic Heating network.

Formation and characterization of FeLV iscoms.

NARCIS (Netherlands)

L. Akerblom; K. Strö mstedt; S. Hö glund; A.D.M.E. Osterhaus (Albert); B. Morein (Bror)

1989-01-01

textabstractImmunostimulating complexes (ISCOMs) have been prepared from feline leukaemia virus (FeLV) envelope proteins. The ISCOMs were characterized biochemically in SDS-polyacrylamide gel electrophoresis showing the presence of proteins of estimated molecular weights of 15,000, 27,000 and

Project of Ariane 5 LV family advancement by use of reusable fly-back boosters (named “Bargouzine”)

Science.gov (United States)

Sumin, Yu.; Bonnal, Ch.; Kostromin, S.; Panichkin, N.

2007-12-01

The paper concerns possible concept variants of a partially reusable Heavy-Lift Launch Vehicle derived from the advanced basic launcher (Ariane-2010) by means of substitution of the EAP Solid Rocket Boosters for a Reusable Starting Stage consisting two Liquid-propellant Reusable Fly-Back Boosters called "Bargouzin". This paper describes the status of the presently studied RFBB concepts during its three phases. The first project phase was dedicated to feasibility expertise of liquid-rocket reusable fly-back boosters ("Baikal" type) utilization for heavy-lift space launch vehicle. The design features and main conclusions are presented. The second phase has been performed with the purpose of selection of preferable concept among the alternative ones for the future Ariane LV modernization by using RFBB instead of EAP Boosters. The main requirements, logic of work, possible configuration and conclusion are presented. Initial aerodynamic, ballistic, thermoloading, dynamic loading, trade-off and comparison analysis have been performed on these concepts. The third phase consists in performing a more detailed expertise of the chosen LV concept. This part summarizes some of the more detailed results related to flight performance, system mass, thermoprotection system, aspects of technologies, ground complex modification, comparison analyses and conclusion.

Driving electrostatic transducers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2013-01-01

Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes power stages and bias configurations suitable for driving an electrostatic transducer. Measurement results of a 300 V prototype amplifier are shown. Measuring THD across a high impedance source is discussed...

Synthetic scaffold coating with adeno-associated virus encoding BMP2 to promote endogenous bone repair.

Science.gov (United States)

Dupont, Kenneth M; Boerckel, Joel D; Stevens, Hazel Y; Diab, Tamim; Kolambkar, Yash M; Takahata, Masahiko; Schwarz, Edward M; Guldberg, Robert E

2012-03-01

Biomaterial scaffolds functionalized to stimulate endogenous repair mechanisms via the incorporation of osteogenic cues offer a potential alternative to bone grafting for the treatment of large bone defects. We first quantified the ability of a self-complementary adeno-associated viral vector encoding bone morphogenetic protein 2 (scAAV2.5-BMP2) to enhance human stem cell osteogenic differentiation in vitro. In two-dimensional culture, scAAV2.5-BMP2-transduced human mesenchymal stem cells (hMSCs) displayed significant increases in BMP2 production and alkaline phosphatase activity compared with controls. hMSCs and human amniotic-fluid-derived stem cells (hAFS cells) seeded on scAAV2.5-BMP2-coated three-dimensional porous polymer Poly(ε-caprolactone) (PCL) scaffolds also displayed significant increases in BMP2 production compared with controls during 12 weeks of culture, although only hMSC-seeded scaffolds displayed significantly increased mineral formation. PCL scaffolds coated with scAAV2.5-BMP2 were implanted into critically sized immunocompromised rat femoral defects, both with or without pre-seeding of hMSCs, representing ex vivo and in vivo gene therapy treatments, respectively. After 12 weeks, defects treated with acellular scAAV2.5-BMP2-coated scaffolds displayed increased bony bridging and had significantly higher bone ingrowth and mechanical properties compared with controls, whereas defects treated with scAAV2.5-BMP2 scaffolds pre-seeded with hMSCs failed to display significant differences relative to controls. When pooled, defect treatment with scAAV2.5-BMP2-coated scaffolds, both with or without inclusion of pre-seeded hMSCs, led to significant increases in defect mineral formation at all time points and increased mechanical properties compared with controls. This study thus presents a novel acellular bone-graft-free endogenous repair therapy for orthotopic tissue-engineered bone regeneration.

Bonding and impedance matching of acoustic transducers using silver epoxy.

Science.gov (United States)

Son, Kyu Tak; Lee, Chin C

2012-04-01

Silver epoxy was selected to bond transducer plates on glass substrates. The properties and thickness of the bonding medium affect the electrical input impedance of the transducer. Thus, the thickness of the silver epoxy bonding layer was used as a design parameter to optimize the structure for the transducer input impedance to match the 50 Ω output impedance of most radio frequency (RF) generators. Simulation and experimental results show that nearly perfect matching is achieved without using any matching circuit. At the matching condition, the transducer operates at a frequency band a little bit below the half-wavelength resonant frequency of the piezoelectric plate. In experiments, lead titanate (PT) piezoelectric plates were employed. Both full-size, 11.5 mm × 2 mm × 0.4 mm, and half-size, 5.75 mm × 2 mm × 0.4 mm, can be well matched using optimal silver epoxy thickness. The transducer assemblies demonstrate high efficiency. The conversion loss from electrical power to acoustic power in soda-lime glass is 4.3 dB. This loss is low considering the fact that the transducers operate at off-resonance by 12%. With proper choice of silver epoxy thickness, the transducer can be matched at the fundamental, the 3rd and 5th harmonic frequencies. This leads to the possible realization of triple-band transducers. Reliability was assessed with thermal cycling test according to Telcordia GR-468-Core recommendation. Of the 30 transducer assemblies tested, none broke until 2900 cycles and 27 have sustained beyond 4050 cycles. Copyright © 2011 Elsevier B.V. All rights reserved.

Acoustic transducer

Science.gov (United States)

Drumheller, Douglas S.

2000-01-01

An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

Biodegradation of di-n-butyl phthalate by bacterial consortium LV-1 enriched from river sludge.

Directory of Open Access Journals (Sweden)

Yangyang Wang

Full Text Available A stable bacterial consortium (LV-1 capable of degrading di-n-butyl phthalate (DBP was enriched from river sludge. Community analysis revealed that the main families of LV-1 are Brucellaceae (62.78% and Sinobacteraceae (14.83%, and the main genera of LV-1 are Brucella spp. (62.78% and Sinobacter spp. (14.83%. The optimal pH and temperature for LV-1 to degrade DBP were pH 6.0 and 30°C, respectively. Inoculum size influenced the degradation ratio when the incubation time was < 24 h. The initial concentration of DBP also influenced the degradation rates of DBP by LV-1, and the degradation rates ranged from 69.0-775.0 mg/l/d in the first 24 h. Degradation of DBP was best fitted by first-order kinetics when the initial concentration was < 300 mg/l. In addition, Cd2+, Cr6+, and Zn2+ inhibited DBP degradation by LV-1 at all considered concentrations, but low concentrations of Pb2+, Cu2+, and Mn2+ enhanced DBP degradation. The main intermediates (mono-ethyl phthalate [MEP], mono-butyl phthalate [MBP], and phthalic acid [PA] were identified in the DBP degradation process, thus a new biochemical pathway of DBP degradation is proposed. Furthermore, LV-1 also degraded other phthalates with shorter ester chains (DMP, DEP, and PA.

Calibration of acoustic emission transducers

International Nuclear Information System (INIS)

Leschek, W.C.

1976-01-01

A method is described for calibrating an acoustic emission transducer to be used in a pre-set frequency range. The absolute reception sensitivity of a reference transducer is determined at frequencies selected within the frequency range. The reference transducer and the acoustic emission transducer are put into acoustic communication with the surface of a limited acoustic medium representing an equivalent acoustic load appreciably identical to that of the medium in which the use of the acoustic emission transducer is intended. A blank random acoustic noise is emitted in the acoustic medium in order to establish a diffuse and reverberating sound field, after which the output responses of the reference transducer and of the acoustic emission transducer are obtained with respect to the diffuse and reverberating field, for selected frequencies. The output response of the acoustic emission transducer is compared with that of the reference transducer for the selected frequencies, so as to determine the reception sensitivity of the acoustic emission transducer [fr

EV Charging Facilities and Their Application in LV Feeders with Photovoltaics

DEFF Research Database (Denmark)

Marra, Francesco; Yang, Guangya; Træholt, Chresten

2013-01-01

Low-voltage (LV) grid feeders with high penetration of photovoltaics (PVs) are often affected by voltage magnitude problems. To solve such issues, previous research has shown that reactive power methods, active power curtailment and grid reinforcement can be used for voltage support, yet showing...... several limits. We introduce the use of electric vehicle (EV) public charging stations with energy storage system (ESS) as a solution for voltage regulation in LV feeders with PV. A novel method is proposed to determine the ESS charging load required for voltage regulation and compare the results...... for the different locations in the feeder. With time-series simulations, we quantify the energy size required for a station ESS. A Belgian LV residential grid, modeled using real PV generation and load profiles, is used as case study. The method and simulation results show the effectiveness of using public EV...

Benazepril inhibited the NF-κB and TGF-β networking on LV hypertrophy in rats.

Science.gov (United States)

Yan, Shi-Hai; Zhao, Ning-Wei; Zhu, Xuan-Xuan; Wang, Qiong; Wang, Hai-Dan; Fu, Rui; Sun, Yuan; Li, Qi-Yi

2013-05-01

Benazepril, an angiotensin-converting enzyme (ACE) inhibitor, has been used to treat hypertension, congestive heart failure, and chronic renal failure. However, its biological activity and mechanism of action in inflammation are not fully identified. The present study was designed to determine the in vivo anti-inflammatory effects of benazepril on LV hypertrophy in rats. LV hypertrophy was produced in rats by abdominal aortic coarctation. They were then divided into the following groups: sham operation; LV hypertrophy; LV hypertrophy+benazepril (1mg/kg in a gavage, once a day for 4 weeks). Both morphological assays (hemodynamic and hemorheological measurement; LV hypertrophy assessment), and molecular assays (protein levels of Collagen type I/III, TNF-α and VCAM-1; TGF-β gene expression; NF-κB or Smad activation; intracellular ROS production) were performed. The following effects were observed in rats treated with benazepril: (1) marked improvements in hemodynamic and hemorheological parameters; (2) significant reductions in LV hypertrophy, dilatation and fibrosis; (3) significantly attenuated protein levels of Collagen type I/III, TGF-β, TNF-α and VCAM-1, NF-κB or Smad activation, as well as intracellular ROS production. These results suggest that the anti-inflammatory properties of benazepril may be ascribed to their down-regulation of both NF-κB and TGF-β signaling pathways by acting on the intracellular ROS production in rats with LV hypertrophy, thus supporting the use of benazepril as an anti-inflammatory agent. Copyright © 2013 Elsevier B.V. All rights reserved.

The B → D*lv form factor at zero recoil

International Nuclear Information System (INIS)

Simone, J.N.; Hashimoto, S.; El-Khadra, A.X.; Kronfeld, A.S.; Mackenzie, P.B.; Ryan, S.M.

2000-01-01

We describe a model independent lattice QCD method for determining the deviation from unity for h A1 (1), the B → D*lv form factor at zero recoil. We extend the double ratio method previously used to determine the B → Dlv form factor. The bulk of statistical and systematic errors cancel in the double ratios we consider, yielding form factors which promise to reduce present theoretical uncertainties in the determination of parallel V cb parallel. We present results from a prototype calculation at a single lattice spacing corresponding to β = 5.7

Resistance to RadLV-induced leukemia: non-participation of splenic natural killer cells

International Nuclear Information System (INIS)

St-Pierre, Y.; Hugo, P.; Lemieux, S.; Lussier, G.; Potworowski, E.F.

1988-01-01

The phenotypic expression of genetically determined resistance to radiation leukemia virus (RadLV)-induced leukemia in mice has been shown to reside in the bone marrow. Because the bone marrow contains precursors of natural killer (NK) cells, known to play a role in retrovirally induced infections, and because these cells have been suggested as participating in resistance to radiation-induced leukemia, it was pertinent to establish whether their levels differed in strains of mice susceptible and resistant to leukemia. We therefore tested splenic NK cell levels in C57BL/Ka (susceptible) and B10.A(5R) (resistant) mice before viral inoculation, immediately after viral inoculation, and throughout the preleukemic period and showed that they were not different. This indicates that splenic NK cell levels have no bearing on the resistance to RadLV-induced leukemia and that other immune or non-immune mechanisms must be sought

3D printed hyperelastic "bone" scaffolds and regional gene therapy: A novel approach to bone healing.

Science.gov (United States)

Alluri, Ram; Jakus, Adam; Bougioukli, Sofia; Pannell, William; Sugiyama, Osamu; Tang, Amy; Shah, Ramille; Lieberman, Jay R

2018-04-01

The purpose of this study was to evaluate the viability of human adipose-derived stem cells (ADSCs) transduced with a lentiviral (LV) vector to overexpress bone morphogenetic protein-2 (BMP-2) loaded onto a novel 3D printed scaffold. Human ADSCs were transduced with a LV vector carrying the cDNA for BMP-2. The transduced cells were loaded onto a 3D printed Hyperelastic "Bone" (HB) scaffold. In vitro BMP-2 production was assessed using enzyme-linked immunosorbent assay analysis. The ability of ADSCs loaded on the HB scaffold to induce in vivo bone formation in a hind limb muscle pouch model was assessed in the following groups: ADSCs transduced with LV-BMP-2, LV-green fluorescent protein, ADSCs alone, and empty HB scaffolds. Bone formation was assessed using radiographs, histology and histomorphometry. Transduced ADSCs BMP-2 production on the HB scaffold at 24 hours was similar on 3D printed HB scaffolds versus control wells with transduced cells alone, and continued to increase after 1 and 2 weeks of culture. Bone formation was noted in LV-BMP-2 animals on plain radiographs at 2 and 4 weeks after implantation; no bone formation was noted in the other groups. Histology demonstrated that the LV-BMP-2 group was the only group that formed woven bone and the mean bone area/tissue area was significantly greater when compared with the other groups. 3D printed HB scaffolds are effective carriers for transduced ADSCs to promote bone repair. The combination of gene therapy and tissue engineered scaffolds is a promising multidisciplinary approach to bone repair with significant clinical potential. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1104-1110, 2018. © 2018 Wiley Periodicals, Inc.

Quantitative Differentiation of LV Myocardium with and without Layer-Specific Fibrosis Using MRI in Hypertrophic Cardiomyopathy and Layer-Specific Strain TTE Analysis.

Science.gov (United States)

Funabashi, Nobusada; Takaoka, Hiroyuki; Ozawa, Koya; Kamata, Tomoko; Uehara, Masae; Komuro, Issei; Kobayashi, Yoshio

2018-05-30

To achieve further risk stratification in hypertrophic cardiomyopathy (HCM) patients, we localized and quantified layer-specific LVM fibrosis on MRI in HCM patients using regional layer-specific peak longitudinal strain (PLS) and peak circumferential strain (PCS) in LV myocardium (LVM) on speckle tracking transthoracic echocardiography (TTE). A total of 18 HCM patients (14 males; 58 ± 17 years) underwent 1.5T-MRI and TTE. PLS and PCS in each layer of the LVM (endocardium, epicardium, and whole-layer myocardium) were calculated for 17 AHA-defined lesions. MRI assessment showed that fibrosis was classified as endocardial, epicardial, or whole-layer (= either or both of these). Regional PLS was smaller in fibrotic endocardial lesions than in non-fibrotic endocardial lesions (P = 0.004). To detect LV endocardial lesions with fibrosis, ROC curves of regional PLS revealed an area under the curve (AUC) of 0.609 and a best cut-off point of 13.5%, with sensitivity of 65.3% and specificity of 54.3%. Regional PLS was also smaller in fibrotic epicardial lesions than in non-fibrotic epicardial lesions (P layer myocardium analysis, PLS was smaller in fibrotic lesions than in non-fibrotic lesions (P layer LV lesions with fibrosis, ROC curves of regional PLS revealed an AUC of 0.674 and a best cut-off point of 12.5%, with sensitivity of 79.0% and specificity of 50.7%. There were no significant differences in PCS of LV myocardium (endocardium, epicardium, and whole-layer) between fibrotic and non-fibrotic lesions. Quantitative regional PLS but not PCS in LV endocardium, epicardium, and whole-layer myocardium provides useful non-invasive information for layer-specific localization of fibrosis in HCM patients.

A randomized phase II study of weekly nab-paclitaxel plus gemcitabine or simplified LV5FU2 as first-line therapy in patients with metastatic pancreatic cancer: the AFUGEM GERCOR trial.

Science.gov (United States)

Bachet, Jean-Baptiste; Chibaudel, Benoist; Bonnetain, Franck; Validire, Pierre; Hammel, Pascal; André, Thierry; Louvet, Christophe

2015-10-06

Metastatic pancreatic adenocarcinoma (PAC) prognosis remains dismal and gemcitabine monotherapy has been the standard treatment over the last decade. Currently, two first-line regimens are used in this setting: FOLFIRINOX and nab-paclitaxel plus gemcitabine. Increasing translational data on the predictive value of hENT1 for determining gemcitabine efficacy suggest that a non-gemcitabine-based regimen is favored in about 60 % of patients with PAC due to high resistance of PAC to this cytotoxic drug. This study aims to evaluate the efficacy of weekly nab-paclitaxel combined with gemcitabine or a simplified (s) LV5FU2 regimen in patients with previously untreated metastatic PAC. AFUGEM is a two-stage, open-label, randomized, multicenter, phase II trial. Patients with PAC who meet the inclusion criteria and provide written informed consent will be randomized in a 1:2 ratio to either nab-paclitaxel (125 mg/m(2)) plus gemcitabine (1000 mg/m(2)) given on days 1, 8, and 15 every 28 days or nab-paclitaxel (125 mg/m(2)) plus sLV5FU2 (leucovorin 400 mg/m(2) followed by bolus 400 mg/m(2) 5-fluorouracil and by 5-fluorouracil 2400 mg/m(2) as an 46-h intravenous infusion) given on days 1 and 15 every 28 days. A total of 114 patients will be randomized to one of the treatment arms. The primary endpoint is progression-free survival at 4 months. Secondary outcomes are rate and duration of response, disease control, overall survival, safety, and quality of life. Potential biomarkers of gemcitabine (hENT1, dCK) and 5-fluorouracil (TS) efficacy will be assessed. The AFUGEM trial is designed to provide valuable information regarding efficacy and tolerability of nab-paclitaxel plus gemcitabine and nab-paclitaxel plus sLV5FU2 regimens. Identification of potential predictive biomarkers of gemcitabine and 5-fluorouracil is likely to drive therapeutic decisions in patients with metastatic PAC. AFUGEM is registered at Clinicaltrials.gov: NCT01964534 , October 15, 2013.

Coalgebraising subsequential transducers

NARCIS (Netherlands)

H.H. Hansen (Helle); J. Adamek; C.A. Kupke (Clemens)

2008-01-01

htmlabstractSubsequential transducers generalise both classic deterministic automata and Mealy/Moore type state machines by combining (input) language recognition with transduction. In this paper we show that normalisation and taking differentials of subsequential transducers and their underlying

The surface glycoprotein of a natural feline leukemia virus subgroup A variant, FeLV-945, as a determinant of disease outcome.

Science.gov (United States)

Bolin, Lisa L; Ahmad, Shamim; Levy, Laura S

2011-10-15

Feline leukemia virus (FeLV) is a natural retrovirus of domestic cats associated with degenerative, proliferative and malignant diseases. Studies of FeLV infection in a cohort of naturally infected cats were undertaken to examine FeLV variation, the selective pressures operative in FeLV infection that lead to predominance of natural variants, and the consequences for infection and disease progression. A unique variant, designated FeLV-945, was identified as the predominant isolate in the cohort and was associated with non-T-cell diseases including multicentric lymphoma. FeLV-945 was assigned to the FeLV-A subgroup based on sequence analysis and receptor utilization, but was shown to differ in sequence from a prototype member of FeLV-A, designated FeLV-A/61E, in the long terminal repeat (LTR) and the surface glycoprotein gene (SU). A unique sequence motif in the FeLV-945 LTR was shown to function as a transcriptional enhancer and to confer a replicative advantage. The FeLV-945 SU protein was observed to differ in sequence as compared to FeLV-A/61E within functional domains known to determine receptor selection and binding. Experimental infection of newborn cats was performed using wild type FeLV-A/61E or recombinant FeLV-A/61E in which the LTR (61E/945L) or LTR and SU (61E/945SL) were exchanged for that of FeLV-945. Infection with either FeLV-A/61E or 61E/945L resulted in T-cell lymphoma of the thymus, although 61E/945L caused disease significantly more rapidly. In contrast, infection with 61E/945SL resulted in the rapid induction of a multicentric lymphoma of B-cell origin, thus recapitulating the outcome of natural infection and implicating FeLV-945 SU as a determinant of disease outcome. Recombinant FeLV-B was detected infrequently and at low levels in multicentric lymphomas, and was thereby not implicated in disease induction. Preliminary studies of receptor interaction indicated that virus particles bearing FeLV-945 SU bind to the FeLV-A receptor more

Coalgebraising Subsequential Transducers

NARCIS (Netherlands)

Hansen, H.H.

2008-01-01

Subsequential transducers generalise both classic deterministic automata and Mealy/Moore type state machines by combining (input) language recognition with transduction. In this paper we show that normalisation and taking differentials of subsequential transducers and their underlying structures can

Protection of LV system against lightning

OpenAIRE

Yordanova Nedyalkova, Greta

2010-01-01

Lightning is a natural hazard and one of the greatest local mysteries. Scientists have not fully understood the mechanism of lightning. It is one of the most beautiful displays in nature and one of the nature's most dangerous phenomenon known to man. Overvoltage due to lightning is a very important problem of LV systems. Some lightning flashes damage buildings and a few kill or injure people and animals, either directly or indirectly, by causing fire and explosions. The need for protect...

Avoided losses on LV networks as a result of microgeneration

Energy Technology Data Exchange (ETDEWEB)

Costa, Paulo Moises [Escola Superior Tecnologia Viseu, Instituto Politecnico Viseu, Campus Politecnico Repeses, 3504-510 Viseu (Portugal); Matos, Manuel A. [INESC Porto, Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

2009-04-15

In the scope of the discussions about microgeneration (and microgrids), the avoided electrical losses are often pointed out as an important value to be credited to those entities. Therefore, methods to assess the impact of microgeneration on losses must be developed in order to support the definition of a suitable regulatory framework for the economic integration of microgeneration on distribution networks. This paper presents an analytical method to quantify the value of avoided losses that microgeneration may produce on LV networks. Intervals of expected avoided losses are used to account for the variation of avoided losses due to the number, size and location of microgenerators, as well as for the kind of load distribution on LV networks. (author)

A Dynamic and Heuristic Phase Balancing Method for LV Feeders

Directory of Open Access Journals (Sweden)

Samad Taghipour Boroujeni

2016-01-01

Full Text Available Due to the single-phase loads and their stochastic behavior, the current in the distribution feeders is not balanced. In addition, the single-phase loads are located in different positions along the LV feeders. So the amount of the unbalanced load and its location affect the feeder losses. An unbalanced load causes the feeder losses and the voltage drop. Because of time-varying behavior of the single-phase loads, phase balancing is a dynamic and combinatorial problem. In this research, a heuristic and dynamic solution for the phase balancing of the LV feeders is proposed. In this method, it is supposed that the loads’ tie could be connected to all phases through a three-phase switch. The aim of the proposed method is to make the feeder conditions as balanced as possible. The amount and the location of single-phase loads are considered in the proposed phase balancing method. Since the proposed method needs no communication interface or no remote controller, it is inexpensive, simple, practical, and robust. Applying this method provides a distributed and dynamic phase balancing control. In addition, the feasibility of reducing the used switches is investigated. The ability of the proposed method in the phase balancing of the LV feeders is approved by carrying out some simulations.

Envelope Proteins of White Spot Syndrome Virus (WSSV Interact with Litopenaeus vannamei Peritrophin-Like Protein (LvPT.

Directory of Open Access Journals (Sweden)

Shijun Xie

Full Text Available White spot syndrome virus (WSSV is a major pathogen in shrimp cultures. The interactions between viral proteins and their receptors on the surface of cells in a frontier target tissue are crucial for triggering an infection. In this study, a yeast two-hybrid (Y2H library was constructed using cDNA obtained from the stomach and gut of Litopenaeus vannamei, to ascertain the role of envelope proteins in WSSV infection. For this purpose, VP37 was used as the bait in the Y2H library screening. Forty positive clones were detected after screening. The positive clones were analyzed and discriminated, and two clones belonging to the peritrophin family were subsequently confirmed as genuine positive clones. Sequence analysis revealed that both clones could be considered as the same gene, LV-peritrophin (LvPT. Co-immunoprecipitation confirmed the interaction between LvPT and VP37. Further studies in the Y2H system revealed that LvPT could also interact with other WSSV envelope proteins such as VP32, VP38A, VP39B, and VP41A. The distribution of LvPT in tissues revealed that LvPT was mainly expressed in the stomach than in other tissues. In addition, LvPT was found to be a secretory protein, and its chitin-binding ability was also confirmed.

Experimental infection of Tilapia Lake Virus (TiLV) in Nile tilapia (Oreochromis niloticus) and red tilapia (Oreochromis spp.).

Science.gov (United States)

Tattiyapong, Puntanat; Dachavichitlead, Worawan; Surachetpong, Win

2017-08-01

Since 2015, a novel orthomyxo-like virus, tilapia lake virus (TiLV) has been associated with outbreaks of disease and massive mortality of cultured Nile and red tilapia (Oreochromis niloticus and Oreochromis spp., respectively) in Thailand. In this study, TiLV was isolated from field samples and propagated in the permissive E-11 cell line, with cytopathic effect (CPE) development within 3-5days post-inoculation. Electron micrographs of infected E-11 cells and fish tissues confirmed the rounded, enveloped virions of 60 to 80nm with characteristics very similar to those of Orthomyxoviridae. In vivo challenge studies showed that high mortality in Nile (86%) and red tilapia (66%) occurred within 4-12days post-infection. The virus was re-isolated from challenged fish tissues in the permissive cell line, and PCR analysis confirmed TiLV as a causative pathogen. The distinct histopathology of challenged fish included massive degeneration and inflammatory cell infiltration in the liver and brain as well as the presence of eosinophilic intracytoplasmic inclusions in hepatocytes and splenic cells. Our results fulfilled Koch's postulates and confirmed that TiLV is an etiologic agent of mass mortality of tilapia in Thailand. The emergence of this virus in many countries has helped increase awareness that it is a potential threat to tilapia aquacultured in Thailand, Asia, and worldwide. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling of ultrasound transducers

DEFF Research Database (Denmark)

Bæk, David

This Ph.D. dissertation addresses ultrasound transducer modeling for medical ultrasound imaging and combines the modeling with the ultrasound simulation program Field II. The project firstly presents two new models for spatial impulse responses (SIR)s to a rectangular elevation focused transducer...... (REFT) and to a convex rectangular elevation focused transducer (CREFT). These models are solvable on an analog time scale and give exact smooth solutions to the Rayleigh integral. The REFT model exhibits a root mean square (RMS) error relative to Field II predictions of 0.41 % at 3400 MHz, and 1.......37 % at 100MHz. The CREFT model exhibits a RMS deviation of 0.01 % relative to the exact numerical solution on a CREFT transducer. A convex non-elevation focused, a REFT, and a linear flat transducer are shown to be covered with the CREFT model as well. Pressure pulses calculated with a one...

Route of delivery influences biodistribution of human bone marrow-derived mesenchymal stromal cells following experimental bone marrow transplantation

Directory of Open Access Journals (Sweden)

Wang FJ

2015-12-01

Full Text Available Mesenchymal stromal cells (MSCs have shown promise as treatment for graft-versus-host disease (GvHD following allogeneic bone marrow transplantation (alloBMT. Mechanisms mediating in vivo effects of MSCs remain largely unknown, including their biodistribution following infusion. To this end, human bone-marrow derived MSCs (hMSCs were injected via carotid artery (IA or tail vein (TV into allogeneic and syngeneic BMT recipient mice. Following xenogeneic transplantation, MSC biodistribution was measured by bioluminescence imaging (BLI using hMSCs transduced with a reporter gene system containing luciferase and by scintigraphic imaging using hMSCs labeled with [99mTc]-HMPAO. Although hMSCs initially accumulated in the lungs in both transplant groups, more cells migrated to organs in alloBMT recipient as measured by in vivo BLI and scintigraphy and confirmed by ex vivo BLI imaging, immunohistochemistry and quantitative RT-PCR. IA injection resulted in persistent whole–body hMSC distribution in alloBMT recipients, while hMSCs were rapidly cleared in the syngeneic animals within one week. In contrast, TV-injected hMSCs were mainly seen in the lungs with fewer cells traveling to other organs. Summarily, these results demonstrate the potential use of IA injection to alter hMSC biodistribution in order to more effectively deliver hMSCs to targeted tissues and microenvironments.

High-frequency Doppler ultrasound transducer for the peripheral circulatory system

Energy Technology Data Exchange (ETDEWEB)

Bae, Youngmin; Yang, Jeongwon; Kang, Uk; Kim, Guanghoon [Korea Electrotechnology Research Institute, Ansan (Korea, Republic of)

2011-12-15

A Doppler ultrasound transducer was designed and implemented to measure the blood flow velocity in tiny vessels near the skin of hands or feet. The geometric parameters of the transducer for defining the observation volume were derived and implemented with an acoustic window made of polystyrene. The observation volume designed in this study was located 6.5 mm from the transducer, which was comparable to the value predicted geometrically. The two-way insertion loss of the transducer was -11.3 dB on ultrasound frequency of 20 MHz, and the 3-dB bandwidth was approximately 2 MHz. In addition, the Doppler shift in the frequency measured by using a Doppler device composed of the transducer and a Doppler signal processing unit was proportional to the flow velocity generated by a homemade flowing system. Finally, we concluded that the transducer could be applied to measure the blood flow velocity in hands or feet.

High-frequency Doppler ultrasound transducer for the peripheral circulatory system

International Nuclear Information System (INIS)

Bae, Youngmin; Yang, Jeongwon; Kang, Uk; Kim, Guanghoon

2011-01-01

A Doppler ultrasound transducer was designed and implemented to measure the blood flow velocity in tiny vessels near the skin of hands or feet. The geometric parameters of the transducer for defining the observation volume were derived and implemented with an acoustic window made of polystyrene. The observation volume designed in this study was located 6.5 mm from the transducer, which was comparable to the value predicted geometrically. The two-way insertion loss of the transducer was -11.3 dB on ultrasound frequency of 20 MHz, and the 3-dB bandwidth was approximately 2 MHz. In addition, the Doppler shift in the frequency measured by using a Doppler device composed of the transducer and a Doppler signal processing unit was proportional to the flow velocity generated by a homemade flowing system. Finally, we concluded that the transducer could be applied to measure the blood flow velocity in hands or feet.

A randomized phase III multicenter trial comparing irinotecan in combination with the Nordic bolus 5-FU and folinic acid schedule or the bolus/infused de Gramont schedule (Lv5FU2) in patients with metastatic colorectal cancer

DEFF Research Database (Denmark)

Glimelius, B; Sørbye, H; Balteskard, L

2008-01-01

not differ (4% versus 6%, P = 0.3). Grade 3/4 neutropenia (11% versus 5%, P = 0.01) and grade 2 alopecia (18% versus 9%, P = 0.002) were more common in the FLIRI group. The 60-day mortality was 2.4% versus 2.1%. CONCLUSIONS: Irinotecan with the bolus Nordic schedule (FLIRI) is a convenient treatment with PFS...... and OS comparable to irinotecan with the Lv5FU2 schedule. Neutropenia and alopecia are more prevalent, but both regimens are equally well tolerated....

Estudio de las cualidades inmunoestimulantes de nuevas bacterias probióticas asociadas al cultivo de lv

OpenAIRE

Gullian, Mariel; Rodríguez, Jenny

2002-01-01

Estudio de las cualidades inmunoestimulantes de nuevas bacterias probióticas asociadas al cultivo de LV Estudio de las cualidades inmunoestimulantes de nuevas bacterias probióticas asociadas al cultivo de LV

Smart transducer with radiomodem

Science.gov (United States)

Pugach, V. N.; Voronin, E. L.

2018-04-01

Systems for measuring different parameters enabling metering and wireless data transmission are an urgent problem in the industry. One of the most promising solutions is the developments of metering instruments enabling radio-link and GSM data transmission. The article describes a transducer operating with temperature sensors of different types as well as with the sensors of other physical values with the output signal represented as current or voltage with subsequent measurement data transmission from the transducer to the computer via radio-link. The article provides transducer measurement accuracy check. The work confirmed the claimed temperature measurement accuracy, noted a stable data transmission via radio link and convenience of work with the transducer and software.

Characterization of Dielectric Electroactive Polymer transducers

DEFF Research Database (Denmark)

Nielsen, Dennis; Møller, Martin B.; Sarban, Rahimullah

2014-01-01

This paper analysis the small-signal model of the Dielectric Electro Active Polymer (DEAP) transducer. The DEAP transducer have been proposed as an alternative to the electrodynamic transducer in sound reproduction systems. In order to understand how the DEAP transducer works, and provide...

Removal of the liquid waste storage tank LV-2 in JRTF. Part 2. Removal works

International Nuclear Information System (INIS)

Kanayama, Fumihiko; Hagiya, Kazuaki; Sunaoshi, Mizuho; Muraguchi, Yoshinori; Satomi, Shinichi; Nemoto, Kouichi; Terunuma, Akihiro; Shiraishi, Kunio; Ito, Shinichi

2011-06-01

Dismantling activities of components in JAERI's Reprocessing Test Facility (JRTF) started from 1996 as a part of decommissioning of this facility. Removing out of a large liquid waste storage tank LV-2 as a whole tank from the annex building B without cutting in pieces to confirm safety and efficiency of this method started from 2006. After preparatory works, ceiling of LV-2 room was opened, and LV-2 was transferred. Useful data such as manpower, radiation control and waste amount through these works were collected, and work efficiency was analyzed by using of these data. (author)

DEVELOPMENTAL STUDIES OF NUCLEAR DIGITAL TRANSDUCERS

Energy Technology Data Exchange (ETDEWEB)

Hyde, James L.

1963-09-15

A pressure transducer based on mechanical modulation of a beam of alpha particles is described. This type of transducer is capable of direct digital pressure measurexnent with corresponding telemetry advantages. Any variable that is sensed through a mechanical displacement is measurable by means of a corresponding member of this transducer family. Preliminary tests of an experimental pressure transducer show an overall accuracy within a few tenths of one percent, with promise of substantial improvement. General characteristics of nuclear digital transducers include exceptional long-term calibration stability and accuracy, independent of ambient environmental effects. Three concepts of systems enipioying these transducers are discussed. (auth)

A New Protection System for Islanding Detection in LV Distribution Systems

Directory of Open Access Journals (Sweden)

Anna Rita Di Fazio

2015-04-01

Full Text Available The growth of penetration of Distributed Generators (DGs is increasing the risk of unwanted islanded operation in Low Voltage (LV distribution systems. In this scenario, the existing anti-islanding protection systems, installed at the DG premises and based on classical voltage and frequency relays, are no longer effective, especially in the cases of islands characterized by a close match between generation and load. In this paper, a new protection system for islanding detection in LV distribution systems is proposed. The classical voltage and frequency relays in the DG interface protections are enriched with an innovative Smart Islanding Detector, which adopts a new passive islanding detection method. The aim is to keep the advantages of the classical relays while overcoming the problem of their limited sensitivity in detecting balanced islands. In the paper, to define the requirements of the anti-islanding protection system, the events causing the islanded operation of the LV distribution systems are firstly identified and classified. Then, referring to proposed protection system, its architecture and operation are described and, eventually, its performance is analyzed and validated by experimental laboratory tests, carried out with a hardware-in-the-loop technique.

Serological survey of Toxoplasma gondii, Dirofilaria immitis, Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) infections in pet cats in Bangkok and vicinities, Thailand.

Science.gov (United States)

Sukhumavasi, Woraporn; Bellosa, Mary L; Lucio-Forster, Araceli; Liotta, Janice L; Lee, Alice C Y; Pornmingmas, Pitcha; Chungpivat, Sudchit; Mohammed, Hussni O; Lorentzen, Leif; Dubey, J P; Bowman, Dwight D

2012-08-13

The seroprevalence of Toxoplasma gondii, Dirofilaria immitis (heartworm), feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) infections was examined using serum or plasma samples from 746 pet cats collected between May and July 2009 from clinics and hospitals located in and around Bangkok, Thailand. The samples were tested for heartworm, FIV, and FeLV using a commercial ELISA. Of the 746 samples, 4.6% (34/746) were positive for heartworm antigen, 24.5% (183/746) had circulating FeLV antigen, and 20.1% (150/746) had antibodies against FIV. In addition, the first 348 submitted samples were tested for T. gondii antibodies using a modified agglutination test (MAT, cut off 1:25); 10.1% (35/348) were seropositive. Of the 348 cats sampled for all four pathogens, 11, 10, and 1 were positive for T. gondii antibodies and FIV antibodies, FeLV antigen, or D. immitis antigen, respectively. Of the 35 T. gondii-seropositive cats, 42.9% (15/35) were co-infected with at least one of the other three pathogens. The presence of antibodies to FIV was significantly associated with both age and gender, while FeLV antigen presence was only associated with age. In the case of FIV, males were twice as likely to be infected as females, and cats over 10 years of age were 13.5 times more likely to be infected than cats less than 1 year of age. FeLV antigen was more common in younger cats, with cats over 10 years of age being 10 times less likely to be FeLV positive than cats under 1 year of age. This is the first survey for these four pathogens affecting feline health in Thailand. Copyright © 2012 Elsevier B.V. All rights reserved.

Lentivector Iterations and Pre-Clinical Scale-Up/Toxicity Testing: Targeting Mobilized CD34+ Cells for Correction of Fabry Disease

Directory of Open Access Journals (Sweden)

Ju Huang

2017-06-01

Full Text Available Fabry disease is a rare lysosomal storage disorder (LSD. We designed multiple recombinant lentivirus vectors (LVs and tested their ability to engineer expression of human α-galactosidase A (α-gal A in transduced Fabry patient CD34+ hematopoietic cells. We further investigated the safety and efficacy of a clinically directed vector, LV/AGA, in both ex vivo cell culture studies and animal models. Fabry mice transplanted with LV/AGA-transduced hematopoietic cells demonstrated α-gal A activity increases and lipid reductions in multiple tissues at 6 months after transplantation. Next we found that LV/AGA-transduced Fabry patient CD34+ hematopoietic cells produced even higher levels of α-gal A activity than normal CD34+ hematopoietic cells. We successfully transduced Fabry patient CD34+ hematopoietic cells with “near-clinical grade” LV/AGA in small-scale cultures and then validated a clinically directed scale-up transduction process in a GMP-compliant cell processing facility. LV-transduced Fabry patient CD34+ hematopoietic cells were subsequently infused into NOD/SCID/Fabry (NSF mice; α-gal A activity corrections and lipid reductions were observed in several tissues 12 weeks after the xenotransplantation. Additional toxicology studies employing NSF mice xenotransplanted with the therapeutic cell product demonstrated minimal untoward effects. These data supported our successful clinical trial application (CTA to Health Canada and opening of a “first-in-the-world” gene therapy trial for Fabry disease.

Crossflow force transducer

International Nuclear Information System (INIS)

Mulcahy, T.M.

1982-05-01

A force transducer for measuring lift and drag coefficients for a circular cylinder in turbulent water flow is presented. In addition to describing the actual design and construction of the strain-gauged force- ring based transducer, requirements for obtained valid fluid force test data are discussed, and pertinent flow test experience is related

Smart curtailment for congestion management in LV distribution network

NARCIS (Netherlands)

Haque, A. N.M.M.; Rahman, M. T.; Nguyen, P. H.; Bliek, F. W.

2016-01-01

The rapid proliferation of distributed energy resources (DERs) leads to capacity challenges, i.e. network congestions, in the low-voltage (LV) distribution networks. A number of strategies are being widely studied to tackle the challenges with direct switching actions such as load shedding or power

A High-Voltage Class D Audio Amplifier for Dielectric Elastomer Transducers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2014-01-01

Dielectric Elastomer (DE) transducers have emerged as a very interesting alternative to the traditional electrodynamic transducer. Lightweight, small size and high maneuverability are some of the key features of the DE transducer. An amplifier for the DE transducer suitable for audio applications...... is proposed and analyzed. The amplifier addresses the issue of a high impedance load, ensuring a linear response over the midrange region of the audio bandwidth (100 Hz – 3.5 kHz). THD+N below 0.1% are reported for the ± 300 V prototype amplifier producing a maximum of 125 Var at a peak efficiency of 95 %....

PREFACE: 5th International Conference on Materials and Applications for Sensors and Transducers (IC-MAST2015)

Science.gov (United States)

Hristoforou, E.; Vlachos, D. S.; Giouroudi, I.; Kar-Narayan, S.; Potirakis, S.

2016-03-01

The 5th International Conference on Materials and Applications for Sensors and Transducers, Mykonos island, Greece, hosted about 110 oral and poster papers and more than 90 participants. IC-MAS, as an international annual conference which tries to meet the needs for various types of sensors, particularly those which may be manufactured by low cost methods (i.e. hybrid sensors, smart specialization devices, particular applications not necessarily requiring integrated micro-nano technologies), covering all types of materials and physical effects, appears to be a necessity. IC-MAST has been established as a high quality international conference by: I. Gathering together multinational researchers from all over the world, working in different materials for sensors and transducers and technical applications of sensors, but also in some cases in the management of the data coming from sensors and transducers. The careful selection of the conference place (like Aegean Sea, Budapest, Prague, Bilbao, Mykonos etc) allows for enjoying the local hospitality and sightseeing. II. Emphasizing in hybrid sensors and smart specialization devices produced by inexpensive methods, without excluding of course micro-nano technology, from all kinds of solid state, liquid and gaseous materials, as well as in particular transducer applications (design and development, as well as use of sensing data) III. Innovatively implementing the Virtual Paper Concept, allowing for large impact of research works presented in the conference by authors who either have no time or no funding support for visiting a conference; this year more than 12 virtual papers are presented in the 5th IC MAST, following a standardized procedure via the our robust and reliable Conference Site (www.icmast.net!) > IV. Allowing for lengthy technical and managerial discussions in terms of sensor, material and instrumentation development; furthermore, the different research groups gathered together are offered the particular

Handbook of force transducers

CERN Document Server

Stefanescu, Dan Mihai

2011-01-01

Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco

Micromachined capacitive ultrasonic immersion transducer array

Science.gov (United States)

Jin, Xuecheng

Capacitive micromachined ultrasonic transducers (cMUTs) have emerged as an attractive alternative to conventional piezoelectric ultrasonic transducers. They offer performance advantages of wide bandwidth and sensitivity that have heretofore been attainable. In addition, micromachining technology, which has benefited from the fast-growing microelectronics industry, enables cMUT array fabrication and electronics integration. This thesis describes the design and fabrication of micromachined capacitive ultrasonic immersion transducer arrays. The basic transducer electrical equivalent circuit is derived from Mason's theory. The effects of Lamb waves and Stoneley waves on cross coupling and acoustic losses are discussed. Electrical parasitics such as series resistance and shunt capacitance are also included in the model of the transducer. Transducer fabrication technology is systematically studied. Device dimension control in both vertical and horizontal directions, process alternatives and variations in membrane formation, via etch and cavity sealing, and metalization as well as their impact on transducer performance are summarized. Both 64 and 128 element 1-D array transducers are fabricated. Transducers are characterized in terms of electrical input impedance, bandwidth, sensitivity, dynamic range, impulse response and angular response, and their performance is compared with theoretical simulation. Various schemes for cross coupling reduction is analyzed, implemented, and verified with both experiments and theory. Preliminary results of immersion imaging are presented using 64 elements 1-D array transducers for active source imaging.

Role of HIV-2 envelope in Lv2-mediated restriction

International Nuclear Information System (INIS)

Reuter, Sandra; Kaumanns, Patrick; Buschhorn, Sabine B.; Dittmar, Matthias T.

2005-01-01

We have characterized envelope protein pseudotyped HIV-2 particles derived from two HIV-2 isolates termed prCBL23 and CBL23 in order to define the role of the envelope protein for the Lv2-mediated restriction to infection. Previously, it has been described that the primary isolate prCBL23 is restricted to infection of several human cell types, whereas the T cell line adapted isolate CBL23 is not restricted in these cell types. Molecular cloning of the two isolates revealed that the env and the gag gene are responsible for the observed phenotype and that this restriction is mediated by Lv2, which is distinct from Ref1/Lv1 (Schmitz, C., Marchant, D., Neil, S.J., Aubin, K., Reuter, S., Dittmar, M.T., McKnight, A., Kizhatil, K., Albritton, L.M., 2004. Lv2, a novel postentry restriction, is mediated by both capsid and envelope. J. Virol. 78 (4), 2006-2016). We generated pseudotyped viruses consisting of HIV-2 (ROD-AΔenv-GFP, ROD-AΔenv-RFP, or ROD-AΔenv-REN) and the prCBL23 or CBL23 envelope proteins as well as chimeric proteins between these envelopes. We demonstrate that a single amino acid exchange at position 74 in the surface unit of CBL23-Env confers restriction to infection. This single point mutation causes tighter CD4 binding, resulting in a less efficient fusion into the cytosol of the restricted cell line. Prevention of endosome formation and prevention of endosome acidification enhance infectivity of the restricted particles for GHOST/X4 cells indicating a degradative lysosomal pathway as a cause for the reduced cytosolic entry. The described restriction to infection of the primary isolate prCBL23 is therefore largely caused by an entry defect. A remaining restriction to infection (19-fold) is preserved when endosomal acidification is prevented. This restriction to infection is also dependent on the presence of the point mutation at position 74 (G74E)

Circuit for Driving Piezoelectric Transducers

Science.gov (United States)

Randall, David P.; Chapsky, Jacob

2009-01-01

The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the

Current status of the Citrus leprosis virus (CiLV -C and its vector Brevipalpus phoenicis (Geijskes

Directory of Open Access Journals (Sweden)

Guillermo León M

2012-08-01

Full Text Available The Citrus leprosis virus CiLV-C is a quarantine disease of economic importance. Over the past 15 years, this disease has spread to several countries of Central and South America. Colombia has about 45,000 hectares of citrus planted with an annual production of 750,000 tonnes. The CiLV-C has only been detected in the departments of Meta, Casanare and recently Tolima. Meta has 4,300 hectares representing 10% of the national cultivated area, and Casanare, where CiLV-C appeared in 2004, has no more than 500 ha planted with citrus. The presence of the Citrus leprosis virus in Colombia could affect the international market for citrus, other crops and ornamental plants with the United States and other countries without the disease. The false spider mite Brevipalpus phoenicis (Geijskes (Acari: Tenuipalpidae is the main vector of the CiLV-C. Disease management is based on control programs of the vector and diminishing host plants. Chemical mite control is expensive, wasteful and generates resistance to different acaricides. This paper provides basic information on CiLV-C and its vector, advances in diagnosis and methods to control the disease and prevention of its spread

Design and fabrication of liner-arroy ultrasonic transducer using KLM and FEM simulation for non-destructive testing

International Nuclear Information System (INIS)

Park, Chan Yuk; Sung, Jin Ho; Jeong, Jong Seob

2015-01-01

In this paper, a linear-array transducer capable of overcoming the faults of a single element and phased array transducers with convex shape for non-destructive ultrasonic testing was designed and fabricated. A 5.5 MHz linear-array transducer was designed using the PiezoCAD program based on the KLM analysis and the PZFlex program based on the FEM analysis. A 2-2 composite structure was employed to achieve broad-band characteristics. A 128 element linear-array transducer was fabricated and its performance was compared with the simulation results. The center frequency of the fabricated transducer was 5.5 Mhzand the -6 dB frequency bandwidth was 70 %. Thus, we expect that the designed transducer can provide an effective inner image of the test material during non-destructive ultrasonic testing.

Design and fabrication of liner-arroy ultrasonic transducer using KLM and FEM simulation for non-destructive testing

Energy Technology Data Exchange (ETDEWEB)

Park, Chan Yuk; Sung, Jin Ho; Jeong, Jong Seob [Dept. of Medical Biotechnology, Dongguk University Biomedi Campus, Goyang (Korea, Republic of)

2015-04-15

In this paper, a linear-array transducer capable of overcoming the faults of a single element and phased array transducers with convex shape for non-destructive ultrasonic testing was designed and fabricated. A 5.5 MHz linear-array transducer was designed using the PiezoCAD program based on the KLM analysis and the PZFlex program based on the FEM analysis. A 2-2 composite structure was employed to achieve broad-band characteristics. A 128 element linear-array transducer was fabricated and its performance was compared with the simulation results. The center frequency of the fabricated transducer was 5.5 Mhzand the -6 dB frequency bandwidth was 70 %. Thus, we expect that the designed transducer can provide an effective inner image of the test material during non-destructive ultrasonic testing.

Transducers and microprocessors in oceanographic applications

Digital Repository Service at National Institute of Oceanography (India)

Desai, R.G.P.; Desa, E.

Transducers used for the sensing of the ten most measured marine parameters have been described in this paper. The ten parameters have been classed under 5 sensor types, namely temperature, pressure, salinity, currents and waves. For each sensor...

Voltage unbalance mitigation in LV networks using three-phase PV systems

DEFF Research Database (Denmark)

Garcia Bajo, Cristina; Hashemi Toghroljerdi, Seyedmostafa; Bækhøj Kjær, Søren

2015-01-01

In this paper a new method is proposed to mitigate voltage unbalance caused by single-phase solar inverters in low voltage (LV) networks. The method is based on uneven reactive power absorption and injection by three-phase solar inverters. Independent control of each phase is performed to achieve...... this uneven injection. The average values of phase voltages at the connection points of the photovoltaic (PV) inverters are used as the references for the balancing algorithm. Voltage unbalance mitigation is achieved by use of this method in different scenarios with variable three-phase and single......-phase inverters penetration in a realistic LV grid. In addition, the overvoltage is reduced by using this method....

Efficient Control of Energy Storage for Increasing the PV Hosting Capacity of LV Grids

DEFF Research Database (Denmark)

Hashemi Toghroljerdi, Seyedmostafa; Østergaard, Jacob

2016-01-01

grid is usually limited by overvoltage, and the efficient control of distributed electrical energy storage systems (EESSs) can considerably increase this capacity. In this paper, a new control approach based on the voltage sensitivity analysis is proposed to prevent overvoltage and increase the PV......Photovoltaic (PV) systems are among the renewable sources that electrical energy systems are adopting with increasing frequency. The majority of already-installed PV systems are decentralized units that are usually connected to lowvoltage (LV) distribution grids. The PV hosting capacity of an LV...... hosting capacity of LV grids by determining dynamic set points for EESS management. The method has the effectiveness of central control methods and can effectively decrease the energy storage required for overvoltage prevention, yet it eliminates the need for a broadband and fast communication. The net...

La piattaforma POS/LV di Applanix nelle applicazioni di laser scanner cinematico

Directory of Open Access Journals (Sweden)

Domenico Santarsiero

2008-03-01

Full Text Available The Applanix POS/LV platform in cinematic laser scanner applicationsOn the 11th of march the GEOmedia editorial unit had the pleasure of hosting a technical meeting dedicated to the Applanix LANDMark new Position and Orientation System for Land Vehicles (POS/LVfield test. The meeting, which is part of an italian tour organized by Louis Nastro (Applanix Director of Land Products and Terenzio Mariani (Sales manager for Italy, helped to test the functionalities of a complete POS/LV system equipped with a laser and an imaging acquisition software installed on board of a SUV.

A new hybrid longitudinal–torsional magnetostrictive ultrasonic transducer

International Nuclear Information System (INIS)

Karafi, Mohammad Reza; Hojjat, Yousef; Sassani, Farrokh

2013-01-01

In this paper, a novel hybrid longitudinal–torsional magnetostrictive ultrasonic transducer (HL–TMUT) is introduced. The transducer is composed of a magnetostrictive exponential horn and a stainless steel tail mass. In this transducer a spiral magnetic field made up of longitudinal and circumferential magnetic fields is applied to the magnetostrictive horn. As a result, the magnetostrictive horn oscillates simultaneously both longitudinally and torsionally in accordance with the Joule and Wiedemann effects. The magnetostrictive exponential horn is designed in such a manner that it has the same longitudinal and torsional resonant frequency. It is made up of ‘2V Permendur’, which has isotropic magnetic properties. The differential equations of the torsional and longitudinal vibration of the horn are derived, and a HL–TMUT is designed with a resonant frequency of 20 573 Hz. The natural frequency and mode shapes of the transducer are considered theoretically and numerically. The experimental results show that this transducer resonates torsionally and longitudinally with frequencies of 20 610 Hz and 20 830 Hz respectively. The maximum torsional displacement is 1.5 mrad m −1 and the maximum longitudinal displacement is 0.6 μm. These are promising features for industrial applications. (paper)

Study on the overcurrent character analysis and its protective system of underground LV distribution networks

Energy Technology Data Exchange (ETDEWEB)

Song, J.; Shi, Z.; Yang, Y.; Shi, W.; Wei, H.; Zhai, S.; Xie, H. [Taiyuan University of Technology, Taiyuan (China)

2001-02-01

The overcurrent fault characteristics in underground LV cable distribution networks is analysed and the fundamental principle of overcurrent protective system is described in this paper. The emphasis is paid to the determination of the characteristic curves of phase-sensitive symmetrical short-circuit protection, the design of negative-sequence current filter and the definition of the mathematical model of overload. Besides, the hardware block diagram and the software flowchart of the protective system, which is controlled by a single chip microcomputer, is also introduced in the paper. The protective system was tested before being applied to the underground LV distribution networks. The results obtained are in conformity with the design specification. It has been verified that the protective distance is extended and the protective sensitivity is improved with the protective system. The field experience has shown that the protective system is stable and reliable, and will be of great application value in the mining industry. 7 refs., 5 figs., 2 tabs.

Phage Pl mutants with altered transducing abilities for Escherichia coli

International Nuclear Information System (INIS)

Wall, J.D.; Harriman, P.D.

1974-01-01

A search was made for mutants of the coliphage P1 with altered transducing frequencies. A method was developed for the rapid assay of transducing frequencies in single plaques using prophage lambda as the transduced bacterial marker. This procedure selects for mutants altered in their ability to package host DNA. Mutants with 5 to 10 times higher or 10 to 20 times lower frequencies than those of wild-type P1 were found. Not only are the markers used for the detection of the mutants affected, but all other markers are similarly affected (not always to the same extent). One of the high transducing frequency mutants is a suppressible amber, indicating that loss of a function increases P1's ability to package host DNA preferentially. (U.S.)

Micromachined Integrated Transducers for Ultrasound Imaging

DEFF Research Database (Denmark)

la Cour, Mette Funding

The purpose of this project is to develop capacitive micromachined ultrasonic transducers (CMUTs) for medical imaging. Medical ultrasound transducers used today are fabricated using piezoelectric materials and bulk processing. To fabricate transducers capable of delivering a higher imaging...

Analysis of critical operating conditions for LV distribution networks with microgrids

Science.gov (United States)

Zehir, M. A.; Batman, A.; Sonmez, M. A.; Font, A.; Tsiamitros, D.; Stimoniaris, D.; Kollatou, T.; Bagriyanik, M.; Ozdemir, A.; Dialynas, E.

2016-11-01

Increase in the penetration of Distributed Generation (DG) in distribution networks, raises the risk of voltage limit violations while contributing to line losses. Especially in low voltage (LV) distribution networks (secondary distribution networks), impacts of active power flows on the bus voltages and on the network losses are more dominant. As network operators must meet regulatory limitations, they have to take into account the most critical operating conditions in their systems. In this study, it is aimed to present the impact of the worst operation cases of LV distribution networks comprising microgrids. Simulation studies are performed on a field data-based virtual test-bed. The simulations are repeated for several cases consisting different microgrid points of connection with different network loading and microgrid supply/demand conditions.

Establishment of a novel feline leukemia virus (FeLV)-negative B-cell cell line from a cat with B-cell lymphoma.

Science.gov (United States)

Mochizuki, Hiroyuki; Takahashi, Masashi; Nishigaki, Kazuo; Ide, Tetsuya; Goto-Koshino, Yuko; Watanabe, Shinya; Sato, Hirofumi; Sato, Masahiko; Kotera, Yukiko; Fujino, Yasuhito; Ohno, Koichi; Uchida, Kazuyuki; Tsujimoto, Hajime

2011-04-15

We established a novel feline B-cell line, MS4, from the neoplastic pleural effusion of a cat with cutaneous B-cell lymphoma. Immunophenotype staining of the MS4 cells was positive for CD20, CD79α, and IgA and negative for CD3, CD4, CD5, CD8α, CD18, CD21, CD22, IgM, IgG, Ig light chain, and MHC class II. PCR analysis for immunoglobulin heavy chain gene rearrangements revealed a monoclonal rearrangement, whereas no clonal rearrangement of the T-cell receptor γ gene was detected. Southern blotting with an exogenous feline leukemia virus (FeLV) U3 probe revealed no integration of exogenous FeLV provirus. The MS4 cell line is the first FeLV-negative feline B-cell lymphoma cell line, and may be used to investigate the pathogenesis of spontaneously occurring feline lymphoma and the development of new therapies. Copyright © 2011 Elsevier B.V. All rights reserved.

Programming macro tree transducers

DEFF Research Database (Denmark)

Bahr, Patrick; Day, Laurence E.

2013-01-01

transducers can be concisely represented in Haskell, and demonstrate the benefits of utilising such an approach with a number of examples. In particular, tree transducers afford a modular programming style as they can be easily composed and manipulated. Our Haskell representation generalises the original...

Effective RNA-silencing strategy of Lv-MSTN/GDF11 gene and its effects on the growth in shrimp, Litopenaeus vannamei.

Science.gov (United States)

Lee, Ji-Hyun; Momani, Jalal; Kim, Young Mog; Kang, Chang-Keun; Choi, Jung-Hwa; Baek, Hae-Ja; Kim, Hyun-Woo

2015-01-01

Myostatin (MSTN), also known as GDF8, is a member of the transforming growth factor-β (TGF-β) superfamily and plays an important role in muscle growth, development, and differentiation. Recently, Lv-MSTN/GDF11, the primitive isoform of MSTN and GDF11, was identified from the shrimp Litopenaeus vannamei. The major production site for Lv-MSTN/GDF11 is in the heart, not the tail muscle, which differs from MSTNs in mammals. Among the three injected RNAs, long dsRNA was the most effective for Lv-MSTN/GDF11 knockdown and transcripts of Lv-MSTN/GDF11 decreased in both the heart (88.85%) and skeletal muscles (43.36%) 72h after injection of 10pmol of long dsRNA. We also found that higher doses of dsRNA did not lead to greater decreases in Lv-MSTN/GDF11 transcripts for amounts between 1pmol and 100pmol. Injection of Lv-MSTN/GDF11 dsRNA did not affect the upregulation of the skeletal actin gene (Lv-ACTINSK) in the tail muscle, but the expression of cytoplasmic and cardiac actins were upregulated in both the heart and tail muscle. Over the course of 8weeks of dsRNA injection, considerably higher mortality (~71%) was seen in the dsRNA-injected group compared to the control group (40%). Surviving shrimp in the dsRNA injected group had a lower growth rate due to the adverse effects of Lv-MSTN/GDF11 knockdown. Lv-MSTN/GDF11 appears to be involved in muscular or neuronal development, but not in doubling muscle fibers, as is the case with mammalian MSTN. Copyright © 2014 Elsevier Inc. All rights reserved.

Biasing of Capacitive Micromachined Ultrasonic Transducers.

Science.gov (United States)

Caliano, Giosue; Matrone, Giulia; Savoia, Alessandro Stuart

2017-02-01

Capacitive micromachined ultrasonic transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are microelectromechanical devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies on its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and high-performance devices, including both 1-D or 2-D arrays. Being capacitive transducers, CMUTs require a high bias voltage to be properly operated in pulse-echo imaging applications. The typical bias supply residual ripple of high-quality high-voltage (HV) generators is in the millivolt range, which is comparable with the amplitude of the received echo signals, and it is particularly difficult to minimize. The aim of this paper is to analyze the classical CMUT biasing circuits, highlighting the features of each one, and to propose two novel HV generator architectures optimized for CMUT biasing applications. The first circuit proposed is an ultralow-residual ripple (generator that uses an extremely stable sinusoidal power oscillator topology. The second circuit employs a commercially available integrated step-up converter characterized by a particularly efficient switching topology. The circuit is used to bias the CMUT by charging a buffer capacitor synchronously with the pulsing sequence, thus reducing the impact of the switching noise on the received echo signals. The small area of the circuit (about 1.5 cm 2 ) makes it possible to generate the bias voltage inside the probe, very close to the CMUT, making the proposed solution attractive for portable applications. Measurements and experiments are shown to demonstrate the effectiveness of the new approaches presented.

Viral Determinants of FeLV Infection and Pathogenesis: Lessons Learned from Analysis of a Natural Cohort

Directory of Open Access Journals (Sweden)

Laura S. Levy

2011-09-01

Full Text Available Detailed analysis has been performed over many years of a geographic and temporal cohort of cats naturally infected with feline leukemia virus (FeLV. Molecular analysis of FeLV present in the diseased tissues and application of those viruses to experimental systems has revealed unique isolates with distinctive disease potential, previously uncharacterized virus-receptor interactions, information about the role of recombinant viruses in disease induction, and novel viral and cellular oncogenes implicated in pathogenesis, among other findings. The studies have contributed to an understanding of the selective forces that lead to predominance of distinctive FeLV isolates and disease outcomes in a natural population.

A Direct Driver for Electrostatic Transducers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2014-01-01

Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes a power stage suitable for driving an electrostatic transducer under biasing. Measurement results of a ±400 V prototype amplifier are shown. THD below 1% is reported....

Vibration transducer calibration techniques

Science.gov (United States)

Brinkley, D. J.

1980-09-01

Techniques for the calibration of vibration transducers used in the Aeronautical Quality Assurance Directorate of the British Ministry of Defence are presented. Following a review of the types of measurements necessary in the calibration of vibration transducers, the performance requirements of vibration transducers, which can be used to measure acceleration, velocity or vibration amplitude, are discussed, with particular attention given to the piezoelectric accelerometer. Techniques for the accurate measurement of sinusoidal vibration amplitude in reference-grade transducers are then considered, including the use of a position sensitive photocell and the use of a Michelson laser interferometer. Means of comparing the output of working-grade accelerometers with that of previously calibrated reference-grade devices are then outlined, with attention given to a method employing a capacitance bridge technique and a method to be used at temperatures between -50 and 200 C. Automatic calibration procedures developed to speed up the calibration process are outlined, and future possible extensions of system software are indicated.

NMR signal transducer

International Nuclear Information System (INIS)

Kucheryaev, A.G.; Oliferchuk, N.L.

1975-01-01

A signal transducer of nuclear magnetic resonance for simultaneously measuring frequency and intensitivity of two various isotope signals, which are in one specimen is described. The transducer represents radiofrequency circuit with two resonance frequences, which is common for two autodyne generators. To decrease measuring time and to increase recording diagram stability the radiofrequency circuit has LC netork, in the inductivity of which investigated specimen is located; a circuit variable capacity is connected in parallel with one of the autodyne generators. Besides the radiofrequency circuit has an inductance coil in series with a standard specimen inside as well as a variable capacitor connected in parallel with the second autodyne generator. An amplitude of oscillation of each resonance frequency is controlled and adjusted separately. The transducer described can be used for the measurement of a nuclei concentration, isotope concentration and for the spin determination

Comparison of low and high frequency transducers in the detection of liver metastases.

Science.gov (United States)

Schacherer, D; Wrede, C; Obermeier, F; Schölmerich, J; Schlottmann, K; Klebl, F

2006-09-01

To evaluate the benefit of the additional use of a high frequency ultrasound probe (7.5 MHz) in finding suspicious liver lesions compared to the examination using a 3.5-MHz transducer only. One hundred and fifty-seven patients with underlying malignant disease were examined with both transducers using one of three ultrasound machines (Siemens Sonoline Elegra, GE Healthcare Logic 9, or Hitachi EUB-8500). Findings on hepatic lesions were collected on a standardised documentation sheet and evaluated by descriptive statistics. Ninety-three patients (59.2% of all patients) showed no evident liver lesion on conventional ultrasound with the 3.5 MHz probe. In 29 patients (18.5%) new suspicious liver lesions were found by using the high frequency transducer. Thirteen of these 29 patients (44.8%) were suspected to suffer from diffuse infiltration of the liver with malignant lesions or at least 10 additional visible lesions. In 14 patients, no liver lesion had been known before high frequency ultrasound examination. The size of newly described liver lesions ranged from 2 mm to 1.5 cm. Time needed for the additional examination with the high frequency transducer ranged between 1 and 15 min with an average of 4.0 min. The additional use of a high frequency transducer in patients with underlying malignant disease slightly extends the examination time, but reveals new, potentially malignant hepatic lesions in almost every fifth patient.

Digital electrostatic acoustic transducer array

KAUST Repository

Carreno, Armando Arpys Arevalo

2016-12-19

In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3µm air gap. The membrane is made out 5µm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.

Digital electrostatic acoustic transducer array

KAUST Repository

Carreno, Armando Arpys Arevalo; Castro, David; Conchouso Gonzalez, David; Kosel, Jü rgen; Foulds, Ian G.

2016-01-01

In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3µm air gap. The membrane is made out 5µm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.

Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

DEFF Research Database (Denmark)

Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik

2013-01-01

We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the transducer geometry, transducer...... change in geometry and that the coupling angle may be used as an additional tuning parameter for improved acoustophoretic control with single-frequency actuation. Further, we find that frequency-modulation actuation is suitable for diminishing such tuning effects and that it is a robust method to produce...... coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5 µm diameter beads and the results with the tunable-angle...

Transducers and arrays for underwater sound

CERN Document Server

Butler, John L

2016-01-01

This improved and updated second edition covers the theory, development, and design of electro-acoustic transducers for underwater applications. This highly regarded text discusses the basics of piezoelectric and magnetostrictive transducers that are currently being used as well as promising new designs. It presents the basic acoustics as well as the specific acoustics data needed in transducer design and evaluation. A broad range of designs of projectors and hydrophones are described in detail along with methods of modeling, evaluation, and measurement. Analysis of projector and hydrophone transducer arrays, including the effects of mutual radiation impedance and numerical models for elements and arrays, are also covered. The book includes new advances in transducer design and transducer materials and has been completely reorganized to be suitable for use as a textbook, as well as a reference or handbook. The new edition contains updates to the first edition, end-of-chapter exercises, and solutions to select...

An enzyme logic bioprotonic transducer

Energy Technology Data Exchange (ETDEWEB)

Miyake, Takeo; Keene, Scott; Deng, Yingxin; Rolandi, Marco, E-mail: rolandi@uw.edu [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195-2120 (United States); Josberger, Erik E. [Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195-2120 (United States); Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500 (United States)

2015-01-01

Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems. We demonstrate the use of a Pd/PdH{sub x} electrode as a bioprotonic transducer that connects H{sup +} currents in solution into an electronic signal. This transducer exploits the reversible formation of PdH{sub x} in solution according to PdH↔Pd + H{sup +} + e{sup −}, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic AND gate for glucose and NAD{sup +}. PdH{sub x} formation and associated electronic current monitors the output drop in pH, thus transducing a biological function into a measurable electronic output.

Peritrophin-like protein from Litopenaeus vannamei (LvPT) involved in white spot syndrome virus (WSSV) infection in digestive tract challenged with reverse gavage

Science.gov (United States)

Xie, Shijun; Li, Fuhua; Zhang, Xiaojun; Zhang, Jiquan; Xiang, Jianhai

2017-11-01

The peritrophic membrane plays an important role in the defense system of the arthropod gut. The digestive tract is considered one of the major tissues targeted by white spot syndrome virus (WSSV) in shrimp. In this study, the nucleotide sequence encoding peritrophin-like protein of Litopenaeus vannamei (LvPT) was amplified from a yeast two-hybrid library of L. vannamei. The epitope peptide of LvPT was predicted with the GenScript OptimumAntigen™ design tool. An anti-LvPT polyclonal antibody was produced and shown to specifically bind a band at 27 kDa, identified as LvPT. The LvPT protein was expressed and its concentration determined. LvPT dsRNA (4 μg per shrimp) was used to inhibit LvPT expression in shrimp, and a WSSV challenge experiment was then performed with reverse gavage. The pleopods, stomachs, and guts were collected from the shrimp at 0, 24, 48, and 72 h post-infection (hpi). Viral load quantification showed that the levels of WSSV were significantly lower in the pleopods, stomachs, and guts of shrimp after LvPT dsRNA interference than in those of the controls at 48 and 72 hpi. Our results imply that LvPT plays an important role during WSSV infection of the digestive tract.

Radiation-resistant pressure transducers

International Nuclear Information System (INIS)

Abbasov, Sh.M.; Kerimova, T.I.

2005-01-01

Full text : The sensitive element of vibrofrequency tensor converter (VTC) is an electromechanical resonator of string type with electrostatic excitation of longitudinal mechanical vibrations. The string is made from tensosensitive thread-like monocrystal n-Ge1-x Six (length 1-5 mm, diameter 8-12 mcm) with current outlet and strictly fixed by ends at plate or deformable surface (in elastic element) at 50 mcm apartheid. With increasing Si atomic percent in n-Ge1-x Six the converter tens sensitivity increases. There has been shown the scheme of pressure transducer which contains monocrystalline silicon membrane and string tens converter from thread-like monocrystal Ge-Si. Using method, when crystal position on membrane while it deforms by pressure, corresponds to free (uptight) state, allowed to obtain the maximum sensitivity in measurement of pressure fluctuation. The transducers of absolute and pressure differential of this type can be used in automated systems of life activity. The high sensitivity of string transducers to pressure exceeding 100 hertz/mm (water column) permits to use them in devices for measuring gas concentration. The combination of optical and deformation methods of measurements forms the basis of their operation. The pressure change occurs due to the fact that gas molecules absorbing the quanta of incident light, become at excited state and then excitation energy of their vibrational-rotatory degrees of freedom converts to the energy of translational motion of molecules, i.e. to heat appropriate to pressure increase. Using these tens converters of high pressure one can prevent the possible accidents on oil pipe-like Baku-Tibilisi-Ceyhan

Micromachined Ultrasonic Transducers for 3-D Imaging

DEFF Research Database (Denmark)

Christiansen, Thomas Lehrmann

of state-of-the-art 3-D ultrasound systems. The focus is on row-column addressed transducer arrays. This previously sparsely investigated addressing scheme offers a highly reduced number of transducer elements, resulting in reduced transducer manufacturing costs and data processing. To produce...... such transducer arrays, capacitive micromachined ultrasonic transducer (CMUT) technology is chosen for this project. Properties such as high bandwidth and high design flexibility makes this an attractive transducer technology, which is under continuous development in the research community. A theoretical...... treatment of CMUTs is presented, including investigations of the anisotropic plate behaviour and modal radiation patterns of such devices. Several new CMUT fabrication approaches are developed and investigated in terms of oxide quality and surface protrusions, culminating in a simple four-mask process...

Parameter sensitivity study of a Field II multilayer transducer model on a convex transducer

DEFF Research Database (Denmark)

Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

2009-01-01

A multilayer transducer model for predicting a transducer impulse response has in earlier works been developed and combined with the Field II software. This development was tested on current, voltage, and intensity measurements on piezoceramics discs (Bæk et al. IUS 2008) and a convex 128 element...... ultrasound imaging transducer (Bæk et al. ICU 2009). The model benefits from its 1D simplicity and hasshown to give an amplitude error around 1.7‐2 dB. However, any prediction of amplitude, phase, and attenuation of pulses relies on the accuracy of manufacturer supplied material characteristics, which may...... is a quantitative calibrated model for a complete ultrasound system. This includes a sensitivity study aspresented here.Statement of Contribution/MethodsThe study alters 35 different model parameters which describe a 128 element convex transducer from BK Medical Aps. The changes are within ±20 % of the values...

Neutron Irradiation Tests of Pressure Transducers in Liquid Helium

CERN Document Server

Amand, J F; Casas-Cubillos, J; Thermeau, J P

1999-01-01

The superconducting magnets of the future Large Hadron Collider (LHC) at CERN will operate in pressurised superfluid helium (1 bar, 1.9 K). About 500 pressure transducers will be placed in the liquid helium bath for monitoring the filling and the pressure transients after resistive transitions. Their precision must remain better than 100 mbar at pressures below 2 bar and better than 5% for higher pressures (up to 20 bar), with temperatures ranging from 1.8 K to 300 K. All the tested transducers are based on the same principle: the fluid or gas is separated from a sealed reference vacuum by an elastic membrane; its deformation indicates the pressure. The transducers will be exposed to high neutron fluence (2 kGy, 1014 n/cm2 per year) during the 20 years of machine operation. This irradiation may induce changes both on the membranes characteristics (leakage, modification of elasticity) and on gauges which measure their deformations. To investigate these effects and select the transducer to be used in the LHC, a...

Using Portable Transducers to Measure Tremor Severity

Directory of Open Access Journals (Sweden)

Rodger Elble

2016-05-01

Full Text Available Background: Portable motion transducers, suitable for measuring tremor, are now available at a reasonable cost. The use of these transducers requires knowledge of their limitations and data analysis. The purpose of this review is to provide a practical overview and example software for using portable motion transducers in the quantification of tremor. Methods: Medline was searched via PubMed.gov in December 2015 using the Boolean expression “tremor AND (accelerometer OR accelerometry OR gyroscope OR inertial measurement unit OR digitizing tablet OR transducer.” Abstracts of 419 papers dating back to 1964 were reviewed for relevant portable transducers and methods of tremor analysis, and 105 papers written in English were reviewed in detail. Results: Accelerometers, gyroscopes, and digitizing tablets are used most commonly, but few are sold for the purpose of measuring tremor. Consequently, most software for tremor analysis is developed by the user. Wearable transducers are capable of recording tremor continuously, in the absence of a clinician. Tremor amplitude, frequency, and occurrence (percentage of time with tremor can be computed. Tremor amplitude and occurrence correlate strongly with clinical ratings of tremor severity. Discussion: Transducers provide measurements of tremor amplitude that are objective, precise, and valid, but the precision and accuracy of transducers are mitigated by natural variability in tremor amplitude. This variability is so great that the minimum detectable change in amplitude, exceeding random variability, is comparable for scales and transducers. Research is needed to determine the feasibility of detecting smaller change using averaged data from continuous long-term recordings with wearable transducers.

Microhydraulic transducer technology for actuation and power generation

Science.gov (United States)

Hagood, Nesbitt W.; Roberts, David C.; Saggere, Laxminarayana; Breuer, Kenneth S.; Chen, Kuo-Shen; Carretero, Jorge A.; Li, Hanqing; Mlcak, Richard; Pulitzer, Seward W.; Schmidt, Martin A.; Spearing, S. Mark; Su, Yu-Hsuan

2000-06-01

The paper introduces a novel transducer technology, called the solid-state micro-hydraulic transducer, currently under development at MIT. The new technology is enabled through integration of micromachining technology, piezoelectrics, and microhydraulic concepts. These micro-hydraulic transducers are capable of bi-directional electromechanical energy conversion, i.e., they can operate as both an actuator that supplies high mechanical force in response to electrical input and an energy generator that transduces electrical energy from mechanical energy in the environment. These transducers are capable of transducing energy at very high specific power output in the order of 1 kW/kg, and thus, they have the potential to enable many novel applications. The concept, the design, and the potential applications of the transducers are presented. Present efforts towards the development of these transducers, and the challenges involved therein, are also discussed.

Transducer selection and application in magnetoacoustic tomography with magnetic induction

International Nuclear Information System (INIS)

Zhou, Yuqi; Wang, Jiawei; Ma, Qingyu; Sun, Xiaodong; Zhang, Dong

2016-01-01

As an acoustic receiver, transducer plays a vital role in signal acquisition and image reconstruction for magnetoacoustic tomography with magnetic induction (MAT-MI). In order to optimize signal acquisition, the expressions of acoustic pressure detection and waveform collection are theoretically studied based on the radiation theory of acoustic dipole and the reception pattern of transducer. Pressure distributions are simulated for a cylindrical phantom model using a planar piston transducer with different radii and bandwidths. The proposed theory is also verified by the experimental measurements of acoustic waveform detection for an aluminum foil cylinder. It is proved that acoustic pressure with sharp and clear boundary peaks can be detected by the large-radius transducer with wide bandwidth, reflecting the differential of the induced Lorentz force accurately, which is helpful for precise conductivity reconstruction. To detect acoustic pressure with acceptable pressure amplitude, peak pressure ratio, amplitude ratio, and improved signal to noise ratio, the scanning radius of 5–10 times the radius of the object should be selected to improve the accuracy of image reconstruction. This study provides a theoretical and experimental basis for transducer selection and application in MAT-MI to obtain reconstructed images with improved resolution and definition.

Transducer selection and application in magnetoacoustic tomography with magnetic induction

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yuqi; Wang, Jiawei; Ma, Qingyu, E-mail: maqingyu@njnu.edu.cn [Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210023 (China); Sun, Xiaodong [China Key System & Integrated Circuit Co., Ltd., Wuxi 214072 (China); Zhang, Dong [Laboratory of Modern Acoustics of MOE, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)

2016-03-07

As an acoustic receiver, transducer plays a vital role in signal acquisition and image reconstruction for magnetoacoustic tomography with magnetic induction (MAT-MI). In order to optimize signal acquisition, the expressions of acoustic pressure detection and waveform collection are theoretically studied based on the radiation theory of acoustic dipole and the reception pattern of transducer. Pressure distributions are simulated for a cylindrical phantom model using a planar piston transducer with different radii and bandwidths. The proposed theory is also verified by the experimental measurements of acoustic waveform detection for an aluminum foil cylinder. It is proved that acoustic pressure with sharp and clear boundary peaks can be detected by the large-radius transducer with wide bandwidth, reflecting the differential of the induced Lorentz force accurately, which is helpful for precise conductivity reconstruction. To detect acoustic pressure with acceptable pressure amplitude, peak pressure ratio, amplitude ratio, and improved signal to noise ratio, the scanning radius of 5–10 times the radius of the object should be selected to improve the accuracy of image reconstruction. This study provides a theoretical and experimental basis for transducer selection and application in MAT-MI to obtain reconstructed images with improved resolution and definition.

Application of SPCALC for chemical and thermodynamic speciation of fluids -example for wells LV-4A, LV-11 and LV-13, Las Tres Virgenes geothermal field, BCS; Aplicacion del SPCALC en la especiacion quimica y termodinamica de fluidos: ejemplo del caso de los pozos LV-4A, LV-11 y LV-13, del campo geotermico de Las Tres Virgenes, BCS

Energy Technology Data Exchange (ETDEWEB)

Viggiano Guerra, J.C.; Sandoval Medina, F.; Flores Armenta, M.C. [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: fernando.sandoval@cfe.gob.mx, E-mail: magaly.flores@cfe.gob.mx; Perez, R.J. [Universidad de Calgary (Canada); Gonzalez Partida, E. [Universidad Nacional Autonoma de Mexico, Centro de Geociencias, Mexico, D.F. (Mexico)

2009-01-15

SPCALC is an excellent software application providing chemical and multi-phase speciation for geothermal fluids. Recently it was acquired by the Comision Federal de Electricidad (CFE) through a contract with the National Autonomous University of Mexico (UNAM) and the University of Calgary, Canada. Software methodology consists of calculating thermodynamic variables, such as activity (a) and fugacity (f) of chemical species, as well as the saturation indices (log Q/K) of mineral phases of the reservoir. In other words, it models the thermodynamic conditions of the reservoir (pH among other) and simulates the fluid-corrosion rate. This allows the software to foresee scaling and corrosion. In this paper, pervasive fluids in Cretaceous granitic rocks penetrated by wells LV-4A, LV-11 and LV-13 in Las Tres Virgenes geothermal field, BCS, are modeled, starting with chemical analyses. The more important ratios among activities [those which influence the fluid-rock interaction (i.e. {sup a}K{sup +}/{sup a}H{sup +}, {sup a}Ca{sup ++}/{sup a}H{sup +}, {sup a}Na{sup +}/{sup a}H{sup +}, {sup a}Mg{sup ++}/{sup a}H{sup +}) and whose results are the minerals visible under a microscope] are graphed in balance diagrams compatible with the pressure (P) and temperature (T) conditions in the reservoir. Epidote (zoisite) is the mineral found in congruent equilibrium with the system. The main mineral association at those conditions (200-250 degrees Celsius and {approx}18 bar), as observed in the well cuttings, is calcite+illite-quartz{+-}epidote, which is explained by the hydrolithic reactions that form replacement calcite in the presence of CO{sub 2}, thus restricting the formation of epidote and eventually eliminating it. The process enhances the CO{sub 2} molarity in the residual fluid, even up to {sup m}CO{sub 2} 1, which means the CO{sub 2} can be diluted back into fluid and intervene again in the process of calcite formation (2HCO{sub 3}{sup -} + Ca{sup ++} = calcite + H{sub 2}O

LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome

International Nuclear Information System (INIS)

Chen, Chun; Li, Dianfu; Miao, Changqing; Zhou, Yanli; Cao, Kejiang; Feng, Jianlin; Lloyd, Michael S.; Chen, Ji

2012-01-01

The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2-3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4 %) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p < 0.05). RFA improved LV synchrony in the entire cohort and in the patients with septal APs (p < 0.01). Phase analysis of gated SPECT MPI demonstrated that LV mechanical dyssynchrony can be present in patients with WPW syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI. (orig.)

LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome

Energy Technology Data Exchange (ETDEWEB)

Chen, Chun; Li, Dianfu; Miao, Changqing; Zhou, Yanli; Cao, Kejiang [First Affiliated Hospital of Nanjing Medical University, Department of Cardiology, Nanjing, Jiangsu (China); Feng, Jianlin [First Affiliated Hospital of Nanjing Medical University, Department of Nuclear Medicine, Nanjing, Jiangsu (China); Lloyd, Michael S. [Emory University School of Medicine, Division of Cardiology, Atlanta, GA (United States); Chen, Ji [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States)

2012-07-15

The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2-3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4 %) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p < 0.05). RFA improved LV synchrony in the entire cohort and in the patients with septal APs (p < 0.01). Phase analysis of gated SPECT MPI demonstrated that LV mechanical dyssynchrony can be present in patients with WPW syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI. (orig.)

Capacitive pressure transducer using flexible films. Junan film wo mochiita seiden yoryoshiki atsukaku transducer

Energy Technology Data Exchange (ETDEWEB)

Yamada, Y.; Tsuchida, N.; Imai, K. (Toyota Technological Institute, Aichi (Japan)); Fujita, K. (Nitto Denko Corp., Osaka (Japan)): Tsuboi, O. (Fujitsu Corp., Tokyo (Japan))

1992-12-20

This paper describes the design, manufacture, and evaluation of a capacitive pressure transducer made of polyimide films. The structure of a pressure transducer cell was first determined, and then, the deflection-stress and capacitance-load characteristics of the surface film were analyzed using finite element methods. For the practical stage of manufacture, a polyimide film was emboss processed and electrodes were deposited on the film to construct a pressure transducer cell to which a Schmidt-trigger detecting circuit was connected. As a consequence of the examination of operational characteristics of the cell, it was found that the actual relation between the deflection and load approximately agreed with the linear analyses, and that the capacitance depended with little hysteresis on the gap regardless of the native visco-elasticity of the film. Furthermore, small stick-slip vibration of a contact rubber surface was detected by the transducer to verify its high sensitivity. 17 refs., 18 figs.

UMG Lenti: novel lentiviral vectors for efficient transgene- and reporter gene expression in human early hematopoietic progenitors.

Directory of Open Access Journals (Sweden)

Emanuela Chiarella

Full Text Available Lentiviral vectors are widely used to investigate the biological properties of regulatory proteins and/or of leukaemia-associated oncogenes by stably enforcing their expression in hematopoietic stem and progenitor cells. In these studies it is critical to be able to monitor and/or sort the infected cells, typically via fluorescent proteins encoded by the modified viral genome. The most popular strategy to ensure co-expression of transgene and reporter gene is to insert between these cDNAs an IRES element, thus generating bi-cistronic mRNAs whose transcription is driven by a single promoter. However, while the product of the gene located upstream of the IRES is generally abundantly expressed, the translation of the downstream cDNA (typically encoding the reporter protein is often inconsistent, which hinders the detection and the isolation of transduced cells. To overcome these limitations, we developed novel lentiviral dual-promoter vectors (named UMG-LV5 and -LV6 where transgene expression is driven by the potent UBC promoter and that of the reporter protein, EGFP, by the minimal regulatory element of the WASP gene. These vectors, harboring two distinct transgenes, were tested in a variety of human haematopoietic cell lines as well as in primary human CD34+ cells in comparison with the FUIGW vector that contains the expression cassette UBC-transgene-IRES-EGFP. In these experiments both UMG-LV5 and UMG-LV6 yielded moderately lower transgene expression than FUIGW, but dramatically higher levels of EGFP, thereby allowing the easy distinction between transduced and non-transduced cells. An additional construct was produced, in which the cDNA encoding the reporter protein is upstream, and the transgene downstream of the IRES sequence. This vector, named UMG-LV11, proved able to promote abundant expression of both transgene product and EGFP in all cells tested. The UMG-LVs represent therefore useful vectors for gene transfer-based studies in

UMG Lenti: novel lentiviral vectors for efficient transgene- and reporter gene expression in human early hematopoietic progenitors.

Science.gov (United States)

Chiarella, Emanuela; Carrà, Giovanna; Scicchitano, Stefania; Codispoti, Bruna; Mega, Tiziana; Lupia, Michela; Pelaggi, Daniela; Marafioti, Maria G; Aloisio, Annamaria; Giordano, Marco; Nappo, Giovanna; Spoleti, Cristina B; Grillone, Teresa; Giovannone, Emilia D; Spina, Raffaella; Bernaudo, Francesca; Moore, Malcolm A S; Bond, Heather M; Mesuraca, Maria; Morrone, Giovanni

2014-01-01

Lentiviral vectors are widely used to investigate the biological properties of regulatory proteins and/or of leukaemia-associated oncogenes by stably enforcing their expression in hematopoietic stem and progenitor cells. In these studies it is critical to be able to monitor and/or sort the infected cells, typically via fluorescent proteins encoded by the modified viral genome. The most popular strategy to ensure co-expression of transgene and reporter gene is to insert between these cDNAs an IRES element, thus generating bi-cistronic mRNAs whose transcription is driven by a single promoter. However, while the product of the gene located upstream of the IRES is generally abundantly expressed, the translation of the downstream cDNA (typically encoding the reporter protein) is often inconsistent, which hinders the detection and the isolation of transduced cells. To overcome these limitations, we developed novel lentiviral dual-promoter vectors (named UMG-LV5 and -LV6) where transgene expression is driven by the potent UBC promoter and that of the reporter protein, EGFP, by the minimal regulatory element of the WASP gene. These vectors, harboring two distinct transgenes, were tested in a variety of human haematopoietic cell lines as well as in primary human CD34+ cells in comparison with the FUIGW vector that contains the expression cassette UBC-transgene-IRES-EGFP. In these experiments both UMG-LV5 and UMG-LV6 yielded moderately lower transgene expression than FUIGW, but dramatically higher levels of EGFP, thereby allowing the easy distinction between transduced and non-transduced cells. An additional construct was produced, in which the cDNA encoding the reporter protein is upstream, and the transgene downstream of the IRES sequence. This vector, named UMG-LV11, proved able to promote abundant expression of both transgene product and EGFP in all cells tested. The UMG-LVs represent therefore useful vectors for gene transfer-based studies in hematopoietic stem and

Drift of IBL LV current and its consequence in IBL distortion

CERN Document Server

The ATLAS collaboration

2015-01-01

The low voltage (LV) current of the IBL modules had been stable since the beginning of the Run2 until the middle of September 2015, but it has been unstable since then (Figure 1). A clear relation is observed between the current rise-up and the total radiation doze (TID) increase, which is considered to be the TID effect reported in . A shutdown of more than 29 hour on October 6 recovered the current largely (Figure 2). With the change of the LV current, the temperature of IBL modules also changes (Figure 3). The change of the thermo-mechanical condition of the IBL resulted in the change of the IBL distortion magnitude, and a clear relation between the module temperature and the distortion magnitude is observed (Figure 4). Through the duration presented in this series of plots, the cooling set temperature of the IBL was kept at -10℃.

Coaxial Transducer

National Research Council Canada - National Science Library

Ruffa, Anthony A

2008-01-01

The invention as disclosed is of a coaxial transducer that uses lead zirconate titanate ceramic or other suitable material as an isolator between the conductors in a coaxial cable to transmit acoustic...

Investigation of focused and unfocused transducer beam patterns in moderately nonlinear absorbing media

Science.gov (United States)

Kharin, Nikolay A.

2001-05-01

The novel solution of the KZK equation for acoustic pressure of the second harmonic in slightly focused beam of a circular transducer was obtained in a closed form for moderately nonlinear absorbing media (Gol'dberg numbers ~ 1). The solution is based on the method of slowly changing wave profile in combination with the method of successive approximations. Two pairs of transducers (Valpey-Fisher Corp.) Were compared to investigate the influence of focusing on the applicability of the moderate nonlinearity approach. The first pair was of 0.25' diameter and the second was of 0.5' diameter. Both pairs has one transducer with flat surface and the other geometrically focused at 4'. The central frequency for all transducers was 5 MHz. Measurements were undertaken in the blood-mimicking solution of water and glycerine. The results demonstrated that for slightly focused transducers with circular apertures, the moderate nonlinearity approach is still valid, as it was proved for flat sources with the same source level, despite the higher pressures in the focal region. The peak pressure for the weakly focused system occurs at a shorter range than focal length.

Interneta sociālie tīkli draugiem.lv, mammam/tetiem.lv un twitter.com kā reklāmas nesēji Latvijā (2009.gads)

OpenAIRE

Vismane, Inese

2010-01-01

Maģistra darba tēma ir „Interneta sociālie tīkli draugiem.lv, mammam/tetiem.lv un twitter.com kā reklāmas nesēji Latvijā (2009.gads)”. Darba mērķis ir izpētīt Latvijas interneta sociālo tīklu vidi kā potenciāli augošu un reklāmai piemērotu, kā arī izpētīt pamanāmākos reklāmas gadījumus šajos portālos. Teorijas daļā tiek apskatīta Web 2.0 ēra, interneta reklāmas un sociālo mediju mārketinga īpatnības, sociālo tīklu fenomens un teorijas, Latvijas reklāmas tirgus un auditorija, kā arī sociāl...

The Dynamic Performance of Flexural Ultrasonic Transducers

Directory of Open Access Journals (Sweden)

Andrew Feeney

2018-01-01

Full Text Available Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems.

‘Lv Peng and his Chinese Art History in Operation, since 1986’

Directory of Open Access Journals (Sweden)

Joshua Gong

2014-06-01

Full Text Available Lv Peng is one of the most influential contemporary Chinese art historians, who began publishing his work in 1986 and introduced various innovative approaches and methods to the field. Even though his work gained momentum in the field, his totalising and continually-revised publication scheme have come under incessant criticism from friends and rivals alike. This article is an attempt at surveying Lv Peng’s oeuvre, while testifying to the value of his art history writings by making his various approaches more legible and systematic. His most popular publications as well as a few projects that are still in progress will be analysed for a more comprehensive understanding of his operational art history.

Mesenchymal stem cells are efficiently transduced with adenoviruses bearing type 35-derived fibers and the transduced cells with the IL-28A gene produces cytotoxicity to lung carcinoma cells co-cultured.

Science.gov (United States)

Suzuki, Takeo; Kawamura, Kiyoko; Li, Quanhai; Okamoto, Shinya; Tada, Yuji; Tatsumi, Koichiro; Shimada, Hideaki; Hiroshima, Kenzo; Yamaguchi, Naoto; Tagawa, Masatoshi

2014-09-25

Transduction of human mesenchymal stem cells (MSCs) with type 5 adenoviruses (Ad5) is limited in the efficacy because of the poor expression level of the coxsackie adenovirus receptor (CAR) molecules. We examined a possible improvement of Ad-mediated gene transfer in MSCs by substituting the fiber region of type 5 Ad with that of type 35 Ad. Expression levels of CAR and CD46 molecules, which are the major receptors for type 5 and type 35 Ad, respectively, were assayed with flow cytometry. We constructed vectors expressing the green fluorescent protein gene with Ad5 or modified Ad5 bearing the type 35 fiber region (AdF35), and examined the infectivity to MSCs with flow cytometry. We investigated anti-tumor effects of MSCs transduced with interleukin (IL)-28A gene on human lung carcinoma cells with a colorimetric assay. Expression of IL-28A receptors was tested with the polymerase chain reaction. A promoter activity of transcriptional regulatory regions in MSCs was determined with a luciferase assay and a tumor growth-promoting ability of MSCs was tested with co-injection of human tumor cells in nude mice. MSCs expressed CD46 but scarcely CAR molecules, and subsequently were transduced with AdF35 but not with Ad5. Growth of MSCs transduced with the IL-28A gene remained the same as that of untransduced cells since MSCs were negative for the IL-28A receptors. The IL-28A-transduced MSCs however suppressed growth of lung carcinoma cells co-cultured, whereas MSCs transduced with AdF35 expressing the β-galactosidase gene did not. A regulatory region of the cyclooygenase-2 gene possessed transcriptional activities greater than other tumor promoters but less than the cytomegalovirus promoter, and MSCs themselves did not support tumor growth in vivo. AdF35 is a suitable vector to transduce MSCs that are resistant to Ad5-mediated gene transfer. MSCs infected with AdF35 that activate an exogenous gene by the cytomegalovirus promoter can be a vehicle to deliver the gene product

Echo signal from rough planar interfaces influence of roughness, angle, range and transducer type

DEFF Research Database (Denmark)

Wilhjelm, Jens E.; Pedersen, P.C.; Jacobsen, S.M.

1998-01-01

The received electrical signal from a pulse-echo system insonifying a planar acoustical interface was measured for varying degrees of rms roughness (0-0.16 mm), angle of incidence (typically +/-7°) and range to the transducer. A planar and a focused 5 MHz transducer was used. When insonifying...... a smooth interface, the normalized spectrum of the received signals for a planar transducer exhibits an increasing number of nulls with increased angle of insonification, as predicted from numerical modeling while the dependence on insonification angle for the focused transducer was smaller and the null...... pattern was much less distinct. For the planar transducer and for the focused transducer with the interface located at the geometrical point of focus, the energy of the received signal as a function of incident angle was approximately Gaussian with maximum at 0°. For the smooth interface, the -3 dB width...

Medium- and high-pressure gauges and transducers produced by laser welding technology

Science.gov (United States)

Daurelio, Giuseppe; Nenci, Fabio; Cinquepalmi, Massimo; Chita, Giuseppe

1998-07-01

Industrial manufacturers produce many types of pressure gauges and transducers according to the applications, for gas or liquid, for high-medium and low pressure ranges. Nowadays the current production technology generally prefers to weld by micro TIG source the metallic corrugated membranes to the gauge or transducer bodies for the products, operating on the low pressure or medium pressure ranges. For the other ones, operating to high pressure range, generally the two components of the transducers are both threaded only and threaded and then circularly welded by micro TIG for the other higher range, till to 1000 bar. In this work the products, operating on the approximately equals 30 divided by 200 bar, are considered. These, when assembled on industrial plants, as an outcome of a non-correct operating sequence, give a 'shifted' electrical signal. This is due to a shift of the 'zero electrical signal' that unbalances the electrical bridge - thin layer sensor - that is the sensitive part of the product. Moreover, for the same problem, often some mechanical settlings of the transducer happen during the first pressure semi-components, with an increasing of the product manufacturing costs. In light of all this, the above referred, in this work the whole transducer has been re-designed according to the specific laser welding technology requirements. On the new product no threaded parts exist but only a circular laser welding with a full penetration depth about 2.5 divided by 3 mm high. Three different alloys have been tested according to the applications and the mechanical properties requested to the transducer. By using a 1.5 KW CO2 laser system many different working parameters have been evaluated for correlating laser parameters to the penetration depths, crown wides, interaction laser-materia times, mechanical and metallurgical properties. Moreover during the laser welding process the measurements of the maximum temperature, reached by the transducer top, has been

Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

DEFF Research Database (Denmark)

Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik

2012-01-01

We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the system geometry, transducer...... in geometry and that the coupling angle may be used as an additional tuning parameter for improved acoustophoretic control with single-frequency actuation. Further, we find that frequency-modulation actuation is suitable for diminishing such tuning effects and that it is a robust method to produce uniform...... coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5-μm-diameter beads and the results with the tunable-angle...

Distributed generation in the Dutch LV network - self-supporting residential area

NARCIS (Netherlands)

Mes, M.; Vanalme, G.M.A.; Myrzik, J.M.A.; Bongaerts, M.; Verbong, G.P.J.; Kling, W.L.

2008-01-01

A self-supporting residential area is seen as an alternative operational approach of power supply in low voltage (LV) networks. The intention of the new approach is to exploit the advantages of distributed generation (DG) and avoid the difficulties, that come with DG when implemented in the

Hematological findings and factors associated with feline leukemia virus (FeLV and feline immunodeficiency virus (FIV positivity in cats from southern Brazil

Directory of Open Access Journals (Sweden)

Fernanda V.A. da Costa

Full Text Available ABSTRACT: Using a retrospective study, 493 cats tested for FeLV and FIV were selected for analysis of the association between hematologic findings and positivity at immunoassay test. Individual and hematologic variables were assessed considering the influence of results using univariate and multivariate logistic regression analysis. Out 153 of the 493 cats were positive for FeLV (31%, 50 were positive for FIV (10.1% and 22 were positive for both FIV and FeLV (4.4%. Multivariate analysis detected significant associations between FeLV infection and age below 1 year (p=0.01, age from 1 to 10 years (p=0.03, and crossbreed (p=0.04. Male cats were more likely to be FIV-positive (p=0.002. Regarding hematological changes, FeLV-positive cats have higher odds to anemia, leukopenia and lymphopenia than FeLV-negative cats. FIV-positive cats are more likely to have anemia than negative. Identification of associated factors related to animal status and correlation of hematological disorders with infection by retroviruses in cats could be useful for detecting these retroviral diseases in cats.

Alterações clínicas e hematológicas em gatos domésticos naturalmente infectados pelo Vírus da Leucemia Felina (FeLV

Directory of Open Access Journals (Sweden)

Nádia Rossi de Almeida

2016-07-01

Full Text Available O Vírus da Leucemia Felina (FeLV é um retrovírus imunossupressor e o maior causador de morte dentre as doenças infecciosas felinas. O FeLV induz ao desenvolvimento de distúrbios degenerativos e/ou mieloproliferativos nos animais infectados, que sucumbem à infecções oportunistas devido à imunossupressão. As alterações nos parâmetros hematológicos em gatos FeLV positivos muitas vezes não condizem com o estado clínico do animal, podendo o mesmo ser um portador assintomático apresentando alterações hematológicas, ou sintomático sem alterações nestes parâmetros. O objetivo do presente estudo foi avaliar as alterações nos parâmetros clínicos e hematológicos de gatos domésticos infectados naturalmente pelo FeLV, nas fases sintomáticas e assintomáticas da doença. Desta forma, foram selecionados 40 gatos domiciliados previamente testados como positivos para o FeLV pela técnica de imunofluorescência indireta. O exame físico foi realizado e os animais foram separados em dois grupos: os gatos sintomáticos e os assintomáticos para a infecção. Amostras de sangue para a realização de hemograma foram coletadas de ambos os grupos e o teste estatístico ANOVA foi realizado para a comparação das alterações hematológicas. O exame clínico indicou 37,5% dos gatos como portadores assintomáticos e 62,5% sintomáticos, sendo a perda de peso e alterações de mucosas os achados mais frequentes. O hemograma evidenciou anemia e linfopenia como os parâmetros hematológicos que apresentaram diferenças estatísticas entre os dois grupos estudados, sendo que 56% dos gatos assintomáticos apresentaram anemia. Em face aos resultados encontrados, concluiu-se que gatos FeLV positivos sintomáticos apresentaram alterações hematológicas condizentes com o quadro de imunossupressão clínico.

Transient receptor potential cation channel, subfamily C, member 5 (TRPC5) is a cold-transducer in the peripheral nervous system.

Science.gov (United States)

Zimmermann, Katharina; Lennerz, Jochen K; Hein, Alexander; Link, Andrea S; Kaczmarek, J Stefan; Delling, Markus; Uysal, Serdar; Pfeifer, John D; Riccio, Antonio; Clapham, David E

2011-11-01

Detection and adaptation to cold temperature is crucial to survival. Cold sensing in the innocuous range of cold (>10-15 °C) in the mammalian peripheral nervous system is thought to rely primarily on transient receptor potential (TRP) ion channels, most notably the menthol receptor, TRPM8. Here we report that TRP cation channel, subfamily C member 5 (TRPC5), but not TRPC1/TRPC5 heteromeric channels, are highly cold sensitive in the temperature range 37-25 °C. We found that TRPC5 is present in mouse and human sensory neurons of dorsal root ganglia, a substantial number of peripheral nerves including intraepithelial endings, and in the dorsal lamina of the spinal cord that receives sensory input from the skin, consistent with a potential TRPC5 function as an innocuous cold transducer in nociceptive and thermosensory nerve endings. Although deletion of TRPC5 in 129S1/SvImJ mice resulted in no temperature-sensitive behavioral changes, TRPM8 and/or other menthol-sensitive channels appear to underpin a much larger component of noxious cold sensing after TRPC5 deletion and a shift in mechanosensitive C-fiber subtypes. These findings demonstrate that highly cold-sensitive TRPC5 channels are a molecular component for detection and regional adaptation to cold temperatures in the peripheral nervous system that is distinct from noxious cold sensing.

Litopenaeus vannamei sterile-alpha and armadillo motif containing protein (LvSARM is involved in regulation of Penaeidins and antilipopolysaccharide factors.

Directory of Open Access Journals (Sweden)

Pei-Hui Wang

Full Text Available The Toll-like receptor (TLR-mediated NF-κB pathway is tightly controlled because overactivation may result in severe damage to the host, such as in the case of chronic inflammatory diseases and cancer. In mammals, sterile-alpha and armadillo motif-containing protein (SARM plays an important role in negatively regulating this pathway. While Caenorhabditis elegans SARM is crucial for an efficient immune response against bacterial and fungal infections, it is still unknown whether Drosophila SARM participates in immune responses. Here, Litopenaeus vannamei SARM (LvSARM was cloned and functionally characterized. LvSARM shared signature domains with and exhibited significant similarities to mammalian SARM. Real-time quantitative PCR analysis indicated that the expression of LvSARM was responsive to Vibrio alginolyticus and white spot syndrome virus (WSSV infections in the hemocyte, gill, hepatopancreas and intestine. In Drosophila S2 cells, LvSARM was widely distributed in the cytoplasm and could significantly inhibit the promoters of the NF-κB pathway-controlled antimicrobial peptide genes (AMPs. Silencing of LvSARM using dsRNA-mediated RNA interference increased the expression levels of Penaeidins and antilipopolysaccharide factors, which are L.vannamei AMPs, and increased the mortality rate after V. alginolyticus infection. Taken together, our results reveal that LvSARM may be a novel component of the shrimp Toll pathway that negatively regulates shrimp AMPs, particularly Penaeidins and antilipopolysaccharide factors.

Regulation of FeLV-945 by c-Myb binding and CBP recruitment to the LTR

Directory of Open Access Journals (Sweden)

Finstad Samantha L

2004-09-01

Full Text Available Abstract Background Feline leukemia virus (FeLV induces degenerative, proliferative and malignant hematologic disorders in its natural host, the domestic cat. FeLV-945 is a viral variant identified as predominant in a cohort of naturally infected animals. FeLV-945 contains a unique sequence motif in the long terminal repeat (LTR comprised of a single copy of transcriptional enhancer followed by a 21-bp sequence triplicated in tandem. The LTR is precisely conserved among independent cases of multicentric lymphoma, myeloproliferative disease and anemia in animals from the cohort. The 21-bp triplication was previously shown to act as a transcriptional enhancer preferentially in hematopoietic cells and to confer a replicative advantage. The objective of the present study was to examine the molecular mechanism by which the 21-bp triplication exerts its influence and the selective advantage responsible for its precise conservation. Results Potential binding sites for the transcription factor, c-Myb, were identified across the repeat junctions of the 21-bp triplication. Such sites would not occur in the absence of the repeat; thus, a requirement for c-Myb binding to the repeat junctions of the triplication would exert a selective pressure to conserve its sequence precisely. Electrophoretic mobility shift assays demonstrated specific binding of c-Myb to the 21-bp triplication. Reporter gene assays showed that the triplication-containing LTR is responsive to c-Myb, and that responsiveness requires the presence of both c-Myb binding sites. Results further indicated that c-Myb in complex with the 21-bp triplication recruits the transcriptional co-activator, CBP, a regulator of normal hematopoiesis. FeLV-945 replication was shown to be positively regulated by CBP in a manner dependent on the presence of the 21-bp triplication. Conclusion Binding sites for c-Myb across the repeat junctions of the 21-bp triplication may account for its precise conservation in

Linear Array Ultrasonic Transducers: Sensitivity and Resolution Study

International Nuclear Information System (INIS)

Kramb, V.A.

2005-01-01

The University of Dayton Research Institute (UDRI) under contract by the US Air Force has designed and integrated a fully automated inspection system for the inspection of turbine engines that incorporates linear phased array ultrasonic transducers. Phased array transducers have been successfully implemented into weld and turbine blade root inspections where the defect types are well known and characterized. Embedded defects in aerospace turbine engine components are less well defined, however. In order to determine the applicability of linear arrays to aerospace inspections the sensitivity of array transducers to embedded defects in engine materials must be characterized. In addition, the implementation of array transducers into legacy inspection procedures must take into account any differences in sensitivity between the array transducer and that of the single element transducer currently used. This paper discusses preliminary results in a study that compares the sensitivity of linear array and conventional single element transducers to synthetic hard alpha defects in a titanium alloy

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

Energy Technology Data Exchange (ETDEWEB)

Flaherty, Julia E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Glissmeyer, John A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-03-18

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilution system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 μm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.

Ultrasonic properties of all-printed piezoelectric polymer transducers

Science.gov (United States)

Wagle, Sanat; Decharat, Adit; Bodö, Peter; Melandsø, Frank

2013-12-01

The ability of producing ultrasonic transducers from screen-printing has been explored experimentally, through printing and characterization of a large number of transducers. In an all-printed test design, 124 transducers with four different electrode sizes ranging from 1 to 4.9 mm2, were printed layer-by-layer on a high performance polyethyleneimine polymer. Inks from ferroelectric and conductive polymers were applied to the active part of a transducer, to provide a good acoustical match between the individual layers. Ultrasonic characterizations of the transducers done by two independent methods provided a broad-banded frequency response with a maximum response around 100 MHz.

Model of a Piezoelectric Transducer

Science.gov (United States)

Goodenow, Debra

2004-01-01

It's difficult to control liquid and gas in propellant tanks in zero gravity. A possible a design would utilize acoustic liquid manipulation (ALM) technology which uses ultrasonic beams conducted through a liquid and solid media, to push gas bubbles in the liquid to desirable locations. We can propel and control the bubble with acoustic radiation pressure by aiming the acoustic waves on the bubble s surface. This allows us to design a so called smart tank in which the ALM devices transfer the gas to the outer wall of the tank and isolating the liquid in the center. Because the heat transfer rate of a gas is lower of that of the liquid it would substantially decrease boil off and provide of for a longer storage life. The ALM beam is composed of little wavelets which are individual waves that constructively interfere with each other to produce a single, combined acoustic wave front. This is accomplished by using a set of synchronized ultrasound transducers arranged in an array. A slight phase offset of these elements allows us to focus and steer the beam. The device that we are using to produce the acoustic beam is called the piezoelectric transducer. This device converts electrical energy to mechanical energy, which appears in the form of acoustic energy. Therefore the behavior of the device is dependent on both the mechanical characteristics, such as its density, cross-sectional area, and its electrical characteristics, such as, electric flux permittivity and coupling factor. These devices can also be set up in a number of modes which are determined by the way the piezoelectric device is arranged, and the shape of the transducer. For this application we are using the longitudinal or thickness mode for our operation. The transducer also vibrates in the lateral mode, and one of the goals of my project is to decrease the amount of energy lost to the lateral mode. To model the behavior of the transducers I will be using Pspice, electric circuit modeling tool, to

Fast response, 2.5K psi (17.24 MPa) transducer for measurement of gas pressure in PWR fuel rods

International Nuclear Information System (INIS)

Piper, T.C.

1976-09-01

A strain gage pressure transducer of 2,500 psi (17.24 MPa) range for operation in a 650 0 F environment is described. Specific design parameters are given along with the calibration results obtained from typical transducers. Appendices delineate the bridge output to be expected and the actual open circuit value of a strain gage calculated from measurements taken with the bridge completed

Coordinated control to mitigate over voltage and under voltage in LV networks

NARCIS (Netherlands)

Viyathukattuva Mohamed Ali, M.M.; Nguyen, H.P.; Cobben, J.F.G.

2016-01-01

Increasing penetration of distributed renewable energy resources (DRES) and smart loads into the LV network lead to new power quality challenges. Important power quality challenges are overvoltage and undervoltage. A number of solutions are already developed to mitigate these voltage variations. In

Identifying activated T cells in reconstituted RAG deficient mice using retrovirally transduced Pax5 deficient pro-B cells.

Directory of Open Access Journals (Sweden)

Nadesan Gajendran

Full Text Available Various methods have been used to identify activated T cells such as binding of MHC tetramers and expression of cell surface markers in addition to cytokine-based assays. In contrast to these published methods, we here describe a strategy to identify T cells that respond to any antigen and track the fate of these activated T cells. We constructed a retroviral double-reporter construct with enhanced green fluorescence protein (EGFP and a far-red fluorescent protein from Heteractis crispa (HcRed. LTR-driven EGFP expression was used to enrich and identify transduced cells, while HcRed expression is driven by the CD40Ligand (CD40L promoter, which is inducible and enables the identification and cell fate tracing of T cells that have responded to infection/inflammation. Pax5 deficient pro-B cells that can give rise to different hematopoietic cells like T cells, were retrovirally transduced with this double-reporter cassette and were used to reconstitute the T cell pool in RAG1 deficient mice that lack T and B cells. By using flow cytometry and histology, we identified activated T cells that had developed from Pax5 deficient pro-B cells and responded to infection with the bacterial pathogen Listeria monocytogenes. Microscopic examination of organ sections allowed visual identification of HcRed-expressing cells. To further characterize the immune response to a given stimuli, this strategy can be easily adapted to identify other cells of the hematopoietic system that respond to infection/inflammation. This can be achieved by using an inducible reporter, choosing the appropriate promoter, and reconstituting mice lacking cells of interest by injecting gene-modified Pax5 deficient pro-B cells.

The research on high power transducer

International Nuclear Information System (INIS)

Zhao Wuling; Li Yubin; Peng Shuwen

2014-01-01

This paper introduces the transducer structure used double PWM mode, the control system design of hardware and software. The transducer has been applied in factory. From the real experiment, it shows that the system has a high reliability. (authors)

Development of tools to manage the operational monitoring and pre-design of the NPP-LV cycle

International Nuclear Information System (INIS)

Perusquia, R.; Arredondo S, C.; Hernandez M, J. L.; Montes T, J. L.; Castillo M, A.; Ortiz S, J. J.

2015-09-01

This paper presents the development of tools to facilitate the management so much, the operational monitoring of boiling water reactors (BWR) of the nuclear power plant of Laguna Verde (NPP-LV) through independent codes, and how to carry out the static calculations corresponding to process of optimized pre-design of the reference cycle next to current cycle. The progress and preliminary results obtained with the program SACal, developed at Instituto Nacional de Investigaciones Nucleares (ININ), central tool to achieve provide a management platform of the operational monitoring and pre-design of NPP-LV cycle are also described. The reached preliminary advances directed to get an Analysis center and automated design of fuel assembly cells are also presented, which together with centers or similar modules related with the fuel reloads form the key part to meet the targets set for the realization of a Management Platform of Nuclear Fuel of the NPP-LV. (Author)

Nano-optomechanical transducer

Science.gov (United States)

Rakich, Peter T; El-Kady, Ihab F; Olsson, Roy H; Su, Mehmet Fatih; Reinke, Charles; Camacho, Ryan; Wang, Zheng; Davids, Paul

2013-12-03

A nano-optomechanical transducer provides ultrabroadband coherent optomechanical transduction based on Mach-wave emission that uses enhanced photon-phonon coupling efficiencies by low impedance effective phononic medium, both electrostriction and radiation pressure to boost and tailor optomechanical forces, and highly dispersive electromagnetic modes that amplify both electrostriction and radiation pressure. The optomechanical transducer provides a large operating bandwidth and high efficiency while simultaneously having a small size and minimal power consumption, enabling a host of transformative phonon and signal processing capabilities. These capabilities include optomechanical transduction via pulsed phonon emission and up-conversion, broadband stimulated phonon emission and amplification, picosecond pulsed phonon lasers, broadband phononic modulators, and ultrahigh bandwidth true time delay and signal processing technologies.

Current distribution in LV networks during 1-phase MV short-circuit

NARCIS (Netherlands)

Waes, van J.B.M.; Provoost, F.; Merwe, van der J.; Cobben, J.F.G.; Deursen, van A.P.J.; van Riet, M.J.M.; Laan, van der P.C.T.

2000-01-01

This paper describes the consequences of a fault in a medium voltage network on the grounding systems at the LV-side. To study the current distribution and to verify the models, we deliberately introduced one phase to ground faults in the 10 kV floating MV network. The selected site was the end of a

Biocorrosion of 316LV steel used in oral cavity due to Desulfotomaculum nigrificans bacteria.

Science.gov (United States)

Mystkowska, Joanna; Ferreira, Jose A; Leszczyńska, Katarzyna; Chmielewska, Sylwia; Dąbrowski, Jan Ryszard; Wieciński, Piotr; Kurzydłowski, Krzysztof Jan

2017-01-01

Corrosion processes of metallic biomaterials in the oral cavity pose a significant limitation to the life and reliable functioning of dental materials. In this article, the influence of environment bacteria Desulfotomaculum nigrificans sulfate reducing bacteria on the corrosion processes of 316LV steel was assessed. After 14 and 28 days of contact of the material with the bacterial environment, the surfaces of the tested biomaterial were observed by means of confocal scanning laser microscopy, and their chemical composition was studied using X-Ray Photoelectron Spectrometry and a scanning transmission electron microscopy. Corrosive changes, the presence of sulfur (with atomic concentration of 0.5%) on the surface of the biomaterial and the presence of a thin oxide layer (thickness of ∼20 nm) under the surface of the steel were observed. This corrosion layer with significant size reduction of grains was characterized by an increased amount of oxygen (18% mas., p < 0.001) in comparison to untreated 316LV steel (where oxygen concentration - 10% mas.). Image analysis conducted using APHELION software indicated that corrosion pits took up ∼2.8% of the total tested surface. The greatest number of corrosion pits had a surface area within the range of 100-200 μm 2 . © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 222-229, 2017. © 2015 Wiley Periodicals, Inc.

Determination of acoustic impedances of multi matching layers for narrowband ultrasonic airborne transducers at frequencies <2.5 MHz - Application of a genetic algorithm.

Science.gov (United States)

Saffar, Saber; Abdullah, Amir

2012-01-01

obtained acoustic impedances do not necessarily correspond to a nowadays available material. Consequently, the values of the acoustic impedances are switched to the nearest values in a large material database. The switched values of the acoustic impedances do not generally give efficient transmission coefficients. Therefore, we proposed, in a second step, the use of a genetic algorithm (GA) to select the best acoustic impedances for matching layers from the material database for a narrow band ultrasonic transducer that work at frequency below the 2.5MHz by considering attenuation. However this bank is rich, the results get better. So the accuracy of the propose method increase by using a lot of materials with exact data for acoustic impedance and their attenuation, especially in high frequency. This yields highly more efficient transmission coefficient. In fact by using increasing number of layer we can increase our chance to find the best sets of materials with valuable both in acoustic impedance and low attenuation. Precisely, the transmission coefficient is almost equal to unity for the all studied cases. Finally the effect of thickness on transmission coefficient is investigated for different layers. The results showed that the transmission coefficient for air media is a function of thickness and sensitive to it even for small variation in thickness. In fact, the sensitivity increases when the differences of acoustic impedances to be high (difference between PZT and air). Copyright © 2011 Elsevier B.V. All rights reserved.

Quantifying grain shape with MorpheoLV: A case study using Holocene glacial marine sediments

Science.gov (United States)

Charpentier, Isabelle; Staszyc, Alicia B.; Wellner, Julia S.; Alejandro, Vanessa

2017-06-01

As demonstrated in earlier works, quantitative grain shape analysis has revealed to be a strong proxy for determining sediment transport history and depositional environments. MorpheoLV, devoted to the calculation of roughness coefficients from pictures of unique clastic sediment grains using Fourier analysis, drives computations for a collection of samples of grain images. This process may be applied to sedimentary deposits assuming core/interval/image archives for the storage of samples collected along depth. This study uses a 25.8 m jumbo piston core, NBP1203 JPC36, taken from a 100 m thick sedimentary drift deposit from Perseverance Drift on the northern Antarctic Peninsula continental shelf. Changes in ocean and ice conditions throughout the Holocene recorded in this sedimentary archive can be assessed by studying grain shape, grain texture, and other proxies. Ninety six intervals were sampled and a total of 2319 individual particle images were used. Microtextures of individual grains observed by SEM show a very high abundance of authigenically precipitated silica that obscures the original grain shape. Grain roughness, computed along depth with MorpheoLV, only shows small variation confirming the qualitative observation deduced from the SEM. Despite this, trends can be seen confirming the reliability of MorpheoLV as a tool for quantitative grain shape analysis.

Quantifying grain shape with MorpheoLV: A case study using Holocene glacial marine sediments

Directory of Open Access Journals (Sweden)

Charpentier Isabelle

2017-01-01

Full Text Available As demonstrated in earlier works, quantitative grain shape analysis has revealed to be a strong proxy for determining sediment transport history and depositional environments. MorpheoLV, devoted to the calculation of roughness coefficients from pictures of unique clastic sediment grains using Fourier analysis, drives computations for a collection of samples of grain images. This process may be applied to sedimentary deposits assuming core/interval/image archives for the storage of samples collected along depth. This study uses a 25.8 m jumbo piston core, NBP1203 JPC36, taken from a ~100 m thick sedimentary drift deposit from Perseverance Drift on the northern Antarctic Peninsula continental shelf. Changes in ocean and ice conditions throughout the Holocene recorded in this sedimentary archive can be assessed by studying grain shape, grain texture, and other proxies. Ninety six intervals were sampled and a total of 2319 individual particle images were used. Microtextures of individual grains observed by SEM show a very high abundance of authigenically precipitated silica that obscures the original grain shape. Grain roughness, computed along depth with MorpheoLV, only shows small variation confirming the qualitative observation deduced from the SEM. Despite this, trends can be seen confirming the reliability of MorpheoLV as a tool for quantitative grain shape analysis.

A new high performance current transducer

International Nuclear Information System (INIS)

Tang Lijun; Lu Songlin; Li Deming

2003-01-01

A DC-100 kHz current transducer is developed using a new technique on zero-flux detecting principle. It was shown that the new current transducer is of high performance, its magnetic core need not be selected very stringently, and it is easy to manufacture

LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome.

Science.gov (United States)

Chen, Chun; Li, Dianfu; Miao, Changqing; Feng, Jianlin; Zhou, Yanli; Cao, Kejiang; Lloyd, Michael S; Chen, Ji

2012-07-01

The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2-3 days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA. Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4%) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI.

Detecting failed elements on phased array ultrasound transducers using the Edinburgh Pipe Phantom

Science.gov (United States)

Inglis, Scott; Pye, Stephen D

2016-01-01

Aims Imaging faults with ultrasound transducers are common. Failed elements on linear and curvilinear array transducers can usually be detected with a simple image uniformity or ‘paperclip’ test. However, this method is less effective for phased array transducers, commonly used in cardiac imaging. The aim of this study was to assess whether the presence of failed elements could be detected through measurement of the resolution integral (R) using the Edinburgh Pipe Phantom. Methods A 128-element paediatric phased array transducer was studied. Failed elements were simulated using layered polyvinyl chloride (PVC) tape as an attenuator and measurements of resolution integral were carried out for several widths of attenuator. Results All widths of attenuator greater than 0.5 mm resulted in a significant reduction in resolution integral and low contrast penetration measurements compared to baseline (p tests to detect failed elements on phased array transducers. Particularly encouraging is the result for low contrast penetration as this is a quick and simple measurement to make and can be performed with many different test objects, thus enabling ‘in-the-field’ checks. PMID:27482276

Steerable Doppler transducer probes

International Nuclear Information System (INIS)

Fidel, H.F.; Greenwood, D.L.

1986-01-01

An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis

A C-band broadband ortho-mode transducer for radioastronomy polarimetry.

Science.gov (United States)

Ferreira, Ivan S; Tello, Camilo; Bergano, Miguel; Villela, Thyrso; Barbosa, Domingos; Smoot, George F

2016-01-01

We describe the design, the construction and performance of a narrow band ortho-mode transducer, currently used in the 5 GHz polarimetric receiver of the Galactic Emission Mapping project. The ortho-mode transducer was designed to achieve a high degree of transmission within the 400 MHz of the GEM band around the 5 GHz (4.8-5.2 GHz). It is composed of a circular-to-square waveguide transition, a septum polarizer, a thin waveguide coupler and a smooth square-to-rectangular waveguide transition with custom waveguide bends to the output ports. Our simulations and measurements show a very low level of cross-polarization of about -60 dB and a good impedance match for all three ports (S11; S22; S33 < -30 dB) with only 0:25 dB of insertion loss offset across the 400 MHz (4.8-5.2 GHz) of the reception bandwidth.

A new ultrasonic transducer for improved contrast nonlinear imaging

International Nuclear Information System (INIS)

Bouakaz, Ayache; Cate, Folkert ten; Jong, Nico de

2004-01-01

Second harmonic imaging has provided significant improvement in contrast detection over fundamental imaging. This improvement is a result of a higher contrast-to-tissue ratio (CTR) achievable at the second harmonic frequency. Nevertheless, the differentiation between contrast and tissue at the second harmonic frequency is still in many situations cumbersome and contrast detection remains nowadays as one of the main challenges, especially in the capillaries. The reduced CTR is mainly caused by the generation of second harmonic energy from nonlinear propagation effects in tissue, which hence obscures the echoes from contrast bubbles. In a previous study, we demonstrated theoretically that the CTR increases with the harmonic number. Therefore the purpose of our study was to increase the CTR by selectively looking to the higher harmonic frequencies. In order to be able to receive these high frequency components (third up to the fifth harmonic), a new ultrasonic phased array transducer has been constructed. The main advantage of the new design is its wide frequency bandwidth. The new array transducer contains two different types of elements arranged in an interleaved pattern (odd and even elements). This design enables separate transmission and reception modes. The odd elements operate at 2.8 MHz and 80% bandwidth, whereas the even elements have a centre frequency of 900 kHz with a bandwidth of 50%. The probe is connected to a Vivid 5 system (GE-Vingmed) and proper software is developed for driving. The total bandwidth of such a transducer is estimated to be more than 150% which enables higher harmonic imaging at an adequate sensitivity and signal to noise ratio compared to standard medical array transducers. We describe in this paper the design and fabrication of the array transducer. Moreover its acoustic properties are measured and its performances for nonlinear contrast imaging are evaluated in vitro and in vivo. The preliminary results demonstrate the advantages of

Transducers for Sound and Vibration - FEM Based Design

DEFF Research Database (Denmark)

Liu, Bin

2001-01-01

Design of transducers for measurement of vibration (piezoelectric accelerometers) and sound (condenser microphones) is a very labour intensive work. The design work is mostly based on experience and on simple analogies to electrical circuit design. Often a time consuming itterative loop is used......: Specification of the transducer, production of a physical prototype, measurements on the prototype, changed specification of the transducer etc. Furthermore are many transducers made based on customer requirements which also increases the amount of required design work. For these reasons there is a need...... for methods that can reduce the design time consumption and the number of itterations. The present work proposes to use finite element based programs for simulating the behaviour of a transducer with a given set of specifications. A simulation program for accelerometers was developed and has been tested...

Design, Simulation and Experimental Evaluation of Tri-Phasic Piezoelectric Composite Transducers

Science.gov (United States)

Tamez, Juan Pedro

Piezoelectric ceramics exhibit excellent piezoelectric and dielectric properties that is the basis of practically all transducers and piezoelectric devices, but their inherent properties, such as brittleness, non-ductility and poor shapeability may limit their applications in areas such as vibration sensing, impact detection, structural health monitoring and other reinforced structures and energy harvesting. To compensate for such limitations, the 1-3 piezoelectric composites transducers have become the material of choice for many high performance ultrasound transducers since it was invented in the late 1970's [ref. Newnham/Cross]. Extensive studies on 1-3 composites have been performed since then to improve the performance of a transducer by modifying their electromechanical coupling, bandwidth, quality factor, and flexibility and by reducing or eliminating the cross talk, i.e., induced noise between the active piezoelectric elements, especially in high power and low frequency applications. These fundamental issues, their possible solutions and their wide impact underline the motivation of the current work in this dissertation report. The motivation for this dissertation was to study and provide a foundation to designing multiphasic piezoelectric transducers that could be useful for multitude of applications. The goal was to improve the 1-3 diphasic composite transducer by eliminating the cross talk between the active piezoelectric elements while maintaining and improving the figures of merit of the design. To achieve the ultimate goal, the steps outlined below were followed: i. Understanding the theoretical and mathematical modeling for tri-phasic piezoelectric composite. ii. Implement Finite Element Analysis (FEA) and simulations of tri-phasic piezoelectric composites where the different active piezoelectric material PZT-5H and PMN-30%PT is surrounded by a vacuum phase that is enclosed by a hexagonal polymer walls. iii. Propose a redesign of the tri

High Temperature, High Power Piezoelectric Composite Transducers

Science.gov (United States)

Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

2014-01-01

Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

Home Automation System Based on Intelligent Transducer Enablers

Science.gov (United States)

Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M.; Dapena, Adriana; González-López, Miguel

2016-01-01

This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet. PMID:27690031

Home Automation System Based on Intelligent Transducer Enablers.

Science.gov (United States)

Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M; Dapena, Adriana; González-López, Miguel

2016-09-28

This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

Home Automation System Based on Intelligent Transducer Enablers

Directory of Open Access Journals (Sweden)

Manuel Suárez-Albela

2016-09-01

Full Text Available This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers, which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

In hypertrophic cardiomyopathy reduction of relative resting myocardial blood flow is related to late enhancement, T2-signal and LV wall thickness.

Directory of Open Access Journals (Sweden)

Katja Hueper

Full Text Available To quantify resting myocardial blood flow (MBF in the left ventricular (LV wall of HCM patients and to determine the relationship to important parameters of disease: LV wall thickness, late gadolinium enhancement (LGE, T2-signal abnormalities (dark and bright signal, LV outflow tract obstruction and age.Seventy patients with proven HCM underwent cardiac MRI. Absolute and relative resting MBF were calculated from cardiac perfusion MRI by using the Fermi function model. The relationship between relative MBF and LV wall thickness, T2-signal abnormalities (T2 dark and T2 bright signal, LGE, age and LV outflow gradient as determined by echocardiography was determined using simple and multiple linear regression analysis. Categories of reduced and elevated perfusion in relation to non- or mildly affected reference segments were defined, and T2-signal characteristics and extent as well as pattern of LGE were examined. Statistical testing included linear and logistic regression analysis, unpaired t-test, odds ratios, and Fisher's exact test.804 segments in 70 patients were included in the analysis. In a simple linear regression model LV wall thickness (p<0.001, extent of LGE (p<0.001, presence of edema, defined as focal T2 bright signal (p<0.001, T2 dark signal (p<0.001 and age (p = 0.032 correlated inversely with relative resting MBF. The LV outflow gradient did not show any effect on resting perfusion (p = 0.901. Multiple linear regression analysis revealed that LGE (p<0.001, edema (p = 0.026 and T2 dark signal (p = 0.019 were independent predictors of relative resting MBF. Segments with reduced resting perfusion demonstrated different LGE patterns compared to segments with elevated resting perfusion.In HCM resting MBF is significantly reduced depending on LV wall thickness, extent of LGE, focal T2 signal abnormalities and age. Furthermore, different patterns of perfusion in HCM patients have been defined, which may represent different stages of

Fabrication and properties of radially C textured PMN-PT cylinders for transducer applications

Science.gov (United States)

Poterala, Stephen F.; Meyer, Richard J.; Messing, Gary L.

2012-07-01

C Textured PMN-PT ceramics have electromechanical properties (d33 = 850-1050 pm/V, k33 = 0.79-0.83) between those of conventional PZT ceramics and relaxor PMN-PT crystals. In this work, we tailor crystallographic orientation in textured PMN-PT ceramics for transducer designs with non-planar poling surfaces. Specifically, omni-directional cylindrical transducer elements were fabricated using monolithic, radially C textured and poled PMN-PT ceramic. Texture was produced by templated grain growth using NBT-PT templates, which were oriented radially by wrapping green ceramic tapes around a cylindrical mandrel. Finished transducer elements measure ˜5 cm in diameter by ˜2.5 cm in height and demonstrate scalability of textured ceramic fabrication techniques. The fabricated cylinders are ˜50 vol. % textured and show high 31-mode electromechanical properties compared to PZT ceramics (d31 = -259 pm/V, k31 = 0.43, ɛT33 = 3000, and Qm = 350). Frequency bandwidth is related to the square of the hoop mode coupling coefficient kh2, which is ˜60% higher in textured PMN-PT cylinders compared to PZT 5H. Finite element simulations show that this parameter may be further increased by improving texture quality to ≥90 vol. %. Radially textured PMN-PT may thus improve performance in omni-directional cylindrical transducers while avoiding the need for segmented single crystal designs.

Acumulación/eliminación de oxitetraciclina en el camarón blanco, lv y su residualidad en dietas artificiales

OpenAIRE

Montoya, Nelson; Reyes, Eduardo

2002-01-01

Acumulación/eliminación de oxitetraciclina en el camarón blanco, LV y su residualidad en dietas artificiales Acumulación/eliminación de oxitetraciclina en el camarón blanco, LV y su residualidad en dietas artificiales

Capacitance high temperature strain transducer by Interatom

International Nuclear Information System (INIS)

Fortmann, M.

1987-01-01

Special strain transducers are necessary to perform structure mechanical experiments on real components under creep-fatigue load. The new development of the transducer was able to solve the problem. In the meantime, different characteristics of the transducer have been examined and many successful applications have been effected. Some important aspects are given in this report. Up to now the longest operation period has been 24000 h on a pipe at 630 0 C service temperature in a conventional power station. (orig./DG) [de

High Temperature Ultrasonic Transducer for Real-time Inspection

Science.gov (United States)

Amini, Mohammad Hossein; Sinclair, Anthony N.; Coyle, Thomas W.

A broadband ultrasonic transducer with a novel porous ceramic backing layer is introduced to operate at 700 °C. 36° Y-cut lithium niobate (LiNbO3) single crystal was selected for the piezoelectric element. By appropriate choice of constituent materials, porosity and pore size, the acoustic impedance and attenuation of a zirconia-based backing layer were optimized. An active brazing alloy with high temperature and chemical stability was selected to bond the transducer layers together. Prototype transducers have been tested at temperatures up to 700 °C. The experiments confirmed that transducer integrity was maintained.

Chymase inhibition prevents fibronectin and myofibrillar loss and improves cardiomyocyte function and LV torsion angle in dogs with isolated mitral regurgitation.

Science.gov (United States)

Pat, Betty; Chen, Yuanwen; Killingsworth, Cheryl; Gladden, James D; Shi, Ke; Zheng, Junying; Powell, Pamela C; Walcott, Greg; Ahmed, Mustafa I; Gupta, Himanshu; Desai, Ravi; Wei, Chih-Chang; Hase, Naoki; Kobayashi, Tsunefumi; Sabri, Abdelkarim; Granzier, Henk; Denney, Thomas; Tillson, Michael; Dillon, A Ray; Husain, Ahsan; Dell'italia, Louis J

2010-10-12

The left ventricular (LV) dilatation of isolated mitral regurgitation (MR) is associated with an increase in chymase and a decrease in interstitial collagen and extracellular matrix. In addition to profibrotic effects, chymase has significant antifibrotic actions because it activates matrix metalloproteinases and kallikrein and degrades fibronectin. Thus, we hypothesize that chymase inhibitor (CI) will attenuate extracellular matrix loss and LV remodeling in MR. We studied dogs with 4 months of untreated MR (MR; n=9) or MR treated with CI (MR+CI; n=8). Cine MRI demonstrated a >40% increase in LV end-diastolic volume in both groups, consistent with a failure of CI to improve a 25% decrease in interstitial collagen in MR. However, LV cardiomyocyte fractional shortening was decreased in MR versus normal dogs (3.71±0.24% versus 4.81±0.31%; P<0.05) and normalized in MR+CI dogs (4.85±0.44%). MRI with tissue tagging demonstrated an increase in LV torsion angle in MR+CI versus MR dogs. CI normalized the significant decrease in fibronectin and FAK phosphorylation and prevented cardiomyocyte myofibrillar degeneration in MR dogs. In addition, total titin and its stiffer isoform were increased in the LV epicardium and paralleled the changes in fibronectin and FAK phosphorylation in MR+CI dogs. These results suggest that chymase disrupts cell surface-fibronectin connections and FAK phosphorylation that can adversely affect cardiomyocyte myofibrillar structure and function. The greater effect of CI on epicardial versus endocardial titin and noncollagen cell surface proteins may be responsible for the increase in torsion angle in chronic MR.

The proviral genome of radiation leukemia virus (RadLV): molecular cloning, restriction analysis and integration sites in tumor cell DNA

International Nuclear Information System (INIS)

Janowski, M.; Merregaert, J.; Nuyten, J.M.; Maisin, J.R.

1984-01-01

An infectious clone of the linear, unintegrated RadLV provirus was obtained by insertion in the plasmid pBR322. Its restriction map was indistinguishable from that of the majority of the multiple proviral copies, which are found apparently at random sites in the DNA of RadLV-induced rat thymic lymphomas [fr

Simultaneous, But Not Consecutive, Combination With Folinate Salts Potentiates 5-Fluorouracil Antitumor Activity In Vitro and In Vivo.

Science.gov (United States)

Di Paolo, Antonello; Orlandi, Paola; Di Desidero, Teresa; Danesi, Romano; Bocci, Guido

2017-08-07

The combination of folinate salts to 5-fluoruracil (5-FU)-based schedules is an established clinical routine in the landscape of colorectal cancer treatment. The aim of this study was to investigate the pharmacological differences between the sequential administration of folinate salts (1 h before, as in clinical routine) followed by 5-FU and the simultaneous administration of both drugs. Proliferation and apoptotic assays were performed on human colon cancer cells exposed to 5-FU, calcium (CaLV), or disodium (NaLV) levofolinate or their simultaneous and sequential combination for 24 and 72 h. TYMS and SLC19A1 gene expression was performed with real-time PCR. In vivo experiments were performed in xenografted nude mice, which were treated with 5-FU escalating doses and CaLV or NaLV alone or in simultaneous and sequential combination. The simultaneous combination of folinate salts and 5-FU was synergistic (NaLV) or additive (CaLV) in a 24-h treatment in both cell lines. In contrast, the sequential combination of both folinate salts and 5-FU was antagonistic at 24 and 72 h. The simultaneous combination of 5-FU and NaLV or CaLV inhibited TYMS gene expression at 24 h, whereas the sequential combination reduced SLC19A1 gene expression. In vivo experiments confirmed the enhanced antitumor activity of the 5-FU + NaLV simultaneous combination with a good toxicity profile, whereas the sequential combination with CaLV failed to potentiate 5-FU activity. In conclusion, only the simultaneous, but not the consecutive, in vitro and in vivo combination of 5-FU and both folinate salt formulations potentiated the antiproliferative effects of the drugs.

Detection of cyclic-fold bifurcation in electrostatic MEMS transducers by motion-induced current

Science.gov (United States)

Park, Sangtak; Khater, Mahmoud; Effa, David; Abdel-Rahman, Eihab; Yavuz, Mustafa

2017-08-01

This paper presents a new detection method of cyclic-fold bifurcations in electrostatic MEMS transducers based on a variant of the harmonic detection of resonance method. The electrostatic transducer is driven by an unbiased harmonic signal at half its natural frequency, ω a   =  1/2 ω o . The response of the transducer consists of static displacement and a series of harmonics at 2 ω a , 4 ω a , and so on. Its motion-induced current is shifted by the excitation frequency, ω a , to appear at 3 ω a , 5 ω a , and higher odd harmonics, providing higher sensitivity to the measurement of harmonic motions. With this method, we successfully detected the variation in the location of the cyclic-fold bifurcation of an encapsulated electrostatic MEMS transducer. We also detected a regime of tapping mode motions subsequent to the bifurcation.

Detection of cyclic-fold bifurcation in electrostatic MEMS transducers by motion-induced current

International Nuclear Information System (INIS)

Park, Sangtak; Abdel-Rahman, Eihab; Khater, Mahmoud; Effa, David; Yavuz, Mustafa

2017-01-01

This paper presents a new detection method of cyclic-fold bifurcations in electrostatic MEMS transducers based on a variant of the harmonic detection of resonance method. The electrostatic transducer is driven by an unbiased harmonic signal at half its natural frequency, ω a   =  1/2  ω o . The response of the transducer consists of static displacement and a series of harmonics at 2  ω a , 4  ω a , and so on. Its motion-induced current is shifted by the excitation frequency, ω a , to appear at 3  ω a , 5  ω a , and higher odd harmonics, providing higher sensitivity to the measurement of harmonic motions. With this method, we successfully detected the variation in the location of the cyclic-fold bifurcation of an encapsulated electrostatic MEMS transducer. We also detected a regime of tapping mode motions subsequent to the bifurcation. (paper)

TGF-β1, GDF-5, and BMP-2 stimulation induces chondrogenesis in expanded human articular chondrocytes and marrow-derived stromal cells.

Science.gov (United States)

Murphy, Meghan K; Huey, Daniel J; Hu, Jerry C; Athanasiou, Kyriacos A

2015-03-01

Replacement of degenerated cartilage with cell-based cartilage products may offer a long-term solution to halt arthritis' degenerative progression. Chondrocytes are frequently used in cell-based FDA-approved cartilage products; yet human marrow-derived stromal cells (hMSCs) show significant translational potential, reducing donor site morbidity and maintaining their undifferentiated phenotype with expansion. This study sought to investigate the effects of transforming growth factor β1 (TGF-β1), growth/differentiation factor 5 (GDF-5), and bone morphogenetic protein 2 (BMP-2) during postexpansion chondrogenesis in human articular chondrocytes (hACs) and to compare chondrogenesis in passaged hACs with that of passaged hMSCs. Through serial expansion, chondrocytes dedifferentiated, decreasing expression of chondrogenic genes while increasing expression of fibroblastic genes. However, following expansion, 10 ng/mL TGF-β1, 100 ng/mL GDF-5, or 100 ng/mL BMP-2 supplementation during three-dimensional aggregate culture each upregulated one or more markers of chondrogenic gene expression in both hACs and hMSCs. Additionally, in both cell types, the combination of TGF-β1, GDF-5, and BMP-2 induced the greatest upregulation of chondrogenic genes, that is, Col2A1, Col2A1/Col1A1 ratio, SOX9, and ACAN, and synthesis of cartilage-specific matrix, that is, glycosaminoglycans (GAGs) and ratio of collagen II/I. Finally, TGF-β1, GDF-5, and BMP-2 stimulation yielded mechanically robust cartilage rich in collagen II and GAGs in both cell types, following 4 weeks maturation. This study illustrates notable success in using the self-assembling method to generate robust, scaffold-free neocartilage constructs using expanded hACs and hMSCs. © 2014 AlphaMed Press.

Development of an optical displacement transducer for CO2 laser auto-focusing

International Nuclear Information System (INIS)

Brown, D.P.D.

1986-01-01

The PCMWP has partially funded the development of an optical displacement transducer by UKAEA Culham Laboratory (Laser Applications Group). This report covers all work which was done up to the end of the 1984/5 financial year. The purpose of the transducer is to sense automatically the standoff gap between the workpiece and a laser cutting head and subsequently to control an auto-focusing head for the CO 2 laser cutting process. Development of the transducer has reached a stage where it can be mounted on an industrial robot and incorporated into a closed loop servo control system so that standoff gap can be closely controlled whilst traversing variable geometry workpieces. The transducer has been shown to be insensitive to angular displacement of the workpiece (within limits) and to workpiece type or surface finish with the exception of transparent materials. Separate trials have shown it to be unaffected by CO 2 laser light and it has been used, with a motorised laser head, to control standoff whilst the laser cuts a range of contoured materials. The scientific principle of the transducer has thus been proved and a laboratory system has been successfully tested. Its performance has matched the specification with the exception of its ability to sense transparent materials. (author)

La piattaforma POS/LV di Applanix nelle applicazioni di laser scanner cinematico

Directory of Open Access Journals (Sweden)

Domenico Santarsiero

2008-03-01

field test. The meeting, which is part of an italian tour organized by Louis Nastro (Applanix Director of Land Products and Terenzio Mariani (Sales manager for Italy, helped to test the functionalities of a complete POS/LV system equipped with a laser and an imaging acquisition software installed on board of a SUV.

Irradiation Testing of Ultrasonic Transducers

International Nuclear Information System (INIS)

Daw, J.; Rempe, J.; Palmer, J.; Tittmann, B.; Reinhardt, B.; Kohse, G.; Ramuhalli, P.; Montgomery, R.; Chien, H.T.; Villard, J.F.

2013-06-01

Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of numerous parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of single, small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of existing knowledge of ultrasonic transducer material survivability under irradiation conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate promising magnetostrictive and piezoelectric transducer performance in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 10 21 n/cm 2 (E> 0.1 MeV). This test will be an instrumented lead test; and real-time transducer performance data will be collected along with temperature and neutron and gamma flux data. By characterizing magnetostrictive and piezoelectric transducer survivability during irradiation, test results will enable the development of novel radiation tolerant ultrasonic sensors for use in Material and Test Reactors (MTRs). The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. (authors)

Information-Quality based LV-Grid-Monitoring Framework and its Application to Power-Quality Control

DEFF Research Database (Denmark)

Findrik, Mislav; Kristensen, Thomas le Fevre; Hinterhofer, Thomas

2015-01-01

The integration of unpredictable renewable energy sources into the low voltage (LV) power grid results in new challenges when it comes to ensuring power quality in the electrical grid. Addressing this problem requires control of not only the secondary substation but also control of flexible assets...... inside the LV grid. In this paper we investigate how the flexibility information of such assets can be accessed by the controller using heterogeneous off-the-shelf communication networks. To achieve this we develop an adaptive monitoring framework, through which the controller can subscribe to the assets......' flexibility information through an API. We define an information quality metric making the monitoring framework able to adapt information access strategies to ensure the information is made available to the controller with the highest possible information quality. To evaluate the monitoring framework...

Correlation of trabeculae and papillary muscles with clinical and cardiac characteristics and impact on CMR measures of LV anatomy and function

NARCIS (Netherlands)

Chuang, Michael L.; Gona, Philimon; Hautvast, Gilion L T F; Salton, Carol J.; Blease, Susan J.; Yeon, Susan B.; Breeuwer, Marcel; O'Donnell, Christopher J.; Manning, Warren J.

2012-01-01

Objectives: The goal of this study was to assess the relationship of left ventricular (LV) trabeculae and papillary muscles (TPM) with clinical characteristics in a community-based, free-living adult cohort and to determine the effect of TPM on quantitative measures of LV volume, mass, and ejection

Ultrasonic Transducer Peak-to-Peak Optical Measurement

Directory of Open Access Journals (Sweden)

Pavel Skarvada

2012-01-01

Full Text Available Possible optical setups for measurement of the peak-to-peak value of an ultrasonic transducer are described in this work. The Michelson interferometer with the calibrated nanopositioner in reference path and laser Doppler vibrometer were used for the basic measurement of vibration displacement. Langevin type of ultrasonic transducer is used for the purposes of Electro-Ultrasonic Nonlinear Spectroscopy (EUNS. Parameters of produced mechanical vibration have to been well known for EUNS. Moreover, a monitoring of mechanical vibration frequency shift with a mass load and sample-transducer coupling is important for EUNS measurement.

Design and fabrication of a double-sided piezoelectric transducer for harvesting vibration power

Energy Technology Data Exchange (ETDEWEB)

Chang, Wei-Tsai; Chen, Ying-Chung [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Kao, Kuo-Sheng [Department of Computer and Communication, Shu-Te University, Kaohsiung, Taiwan, ROC (China); Chu, Yu-Hsien [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Cheng, Chien-Chuan, E-mail: chengccc@dlit.edu.tw [Department of Electronic Engineering, De Lin Institute of Technology, Taipei, Taiwan, ROC (China)

2013-02-01

This investigation examines a means of integrating high-performance ZnO piezoelectric thin films with a flexible stainless steel substrate (SUS304) to fabricate a double-sided piezoelectric transducer for vibration-energy harvesting applications. The double-sided piezoelectric transducer is constructed by depositing ZnO piezoelectric thin films on both the front and the back sides of the SUS304 substrate. The titanium and platinum layers were deposited using a dual-gun DC sputtering system between the ZnO piezoelectric thin film and the back side of the SUS304 substrate. The scanning electron microscopy and X-ray diffraction of ZnO piezoelectric films reveal a rigid surface structure and a highly c-axis-preferring orientation. To fabricate a transducer with a low resonant frequency, a tip-mass of 0.5 g and a vibration-area of 1 cm{sup 2} are designed, based on the cantilever vibration theory. The maximum open circuit voltage of the power transducer is approximately 18 V. After rectification and filtering through a 33 nF capacitor, a specific power output of 1.31 μW/cm{sup 2} is obtained from the transducers with a load resistance of 6 MΩ. The variation of the power output of ± 0.001% is obtained after 24-hour continuous test. - Highlights: ► A double-sided piezoelectric transducer is fabricated with the ZnO thin films. ► Vibrated frequency of a double-sided transducer is designed and presented. ► A maximum output power of 3.23 μW/cm{sup 2} is obtained under turbulent vibration.

Piezoelectric Nanotube Array for Broadband High-Frequency Ultrasonic Transducer.

Science.gov (United States)

Liew, Weng Heng; Yao, Kui; Chen, Shuting; Tay, Francis Eng Hock

2018-03-01

Piezoelectric materials are vital in determining ultrasonic transducer and imaging performance as they offer the function for conversion between mechanical and electrical energy. Ultrasonic transducers with high-frequency operation suffer from performance degradation and fabrication difficulty of the demanded piezoelectric materials. Hence, we propose 1-D polymeric piezoelectric nanostructure with controlled nanoscale features to overcome the technical limitations of high-frequency ultrasonic transducers. For the first time, we demonstrate the integration of a well-aligned piezoelectric nanotube array to produce a high-frequency ultrasonic transducer with outstanding performance. We find that nanoconfinement-induced polarization orientation and unique nanotube structure lead to significantly improved piezoelectric and ultrasonic transducing performance over the conventional piezoelectric thin film. A large bandwidth, 126% (-6 dB), is achieved at high center frequency, 108 MHz. Transmission sensitivity of nanotube array is found to be 46% higher than that of the monolithic thin film transducer attributed to the improved electromechanical coupling effectiveness and impedance match. We further demonstrate high-resolution scanning, ultrasonic imaging, and photoacoustic imaging using the obtained nanotube array transducers, which is valuable for biomedical imaging applications in the future.

Ultrasonic Transducer Fabricated Using Lead-Free BFO-BTO+Mn Piezoelectric 1-3 Composite

Directory of Open Access Journals (Sweden)

Yan Chen

2015-05-01

Full Text Available Mn-doped 0.7BiFeO3-0.3BaTiO3 (BFO-0.3BTO+Mn 1% mol lead-free piezoelectric ceramic were fabricated by traditional solid state reaction. The phase structure, microstructure, and ferroelectric properties were investigated. Additionally, lead-free 1–3 composites with 60% volume fraction of BFO-BTO+Mn ceramic were fabricated for ultrasonic transducer applications by a conventional dice-and-fill method. The BFO-BTO+Mn 1-3 composite has a higher electromechanical coupling coefficient (kt = 46.4% and lower acoustic impedance (Za ~ 18 MRayls compared with that of the ceramic. Based on this, lead-free piezoelectric ceramic composite, single element ultrasonic transducer with a center frequency of 2.54 MHz has been fabricated and characterized. The single element transducer exhibits good performance with a broad bandwidth of 53%. The insertion loss of the transducer was about 33.5 dB.

Analysis of eigenfrequencies in piezoelectric transducers using the finite element method

DEFF Research Database (Denmark)

Jensen, Henrik

1988-01-01

transducers, which include the complete set of piezoelectric equations, have been included. They can find eigenfrequencies for undamped transducers and perform forced-response analysis for transducers with internal and radiation damping. The superelement technique is used to model the transducer backing......It is noted that the finite-element method is a valuable supplement to the traditional methods for design of novel transducer types because it can determine the vibrational pattern of piezoelectric transducers and is applicable to any geometry. Computer programs for analysis of axisymmetric...

Development of conductor feedthrough module of LV electrical penetration assembly for research reactors

International Nuclear Information System (INIS)

Luo Zhiyuan; Wang Guangjin; Zhou Bin

2007-01-01

A LV electrical penetration assembly with perfusion sealing conductor feedthrough module was developed, which can be used for the connection of internal and external cables through the wall of the research reactor workshop. The LV electrical penetration assembly was combined with several independent modules. The maintenance and replacement of the assembly can be easily done in service. The sealing of conductor feedthrough module was achieved with the perfusion of self-extinguishing epoxy. The leakage between the conductor feedthrough module and the end plate module was blocked with rubber rings. The result of the leakage test and the electrical performance test for the samples of conductor feedthrough module satisfied the requirement of research reactor. The structure of the new electrical penetration assembly is simple and compact. It can be manufactured with mature technology and cost low price. The performance of the assembly is steady. It can be used widely in research reactors. (authors)

LV reverse remodeling imparted by aortic valve replacement for severe aortic stenosis; is it durable? A cardiovascular MRI study sponsored by the American Heart Association

Directory of Open Access Journals (Sweden)

Caruppannan Ketheswaram

2011-04-01

Full Text Available Abstract Background In patients with severe aortic stenosis (AS, long-term data tracking surgically induced effects of afterload reduction on reverse LV remodeling are not available. Echocardiographic data is available short term, but in limited fashion beyond one year. Cardiovascular MRI (CMR offers the ability to serially track changes in LV metrics with small numbers due to its inherent high spatial resolution and low variability. Hypothesis We hypothesize that changes in LV structure and function following aortic valve replacement (AVR are detectable by CMR and once triggered by AVR, continue for an extended period. Methods Tweny-four patients of which ten (67 ± 12 years, 6 female with severe, but compensated AS underwent CMR pre-AVR, 6 months, 1 year and up to 4 years post-AVR. 3D LV mass index, volumetrics, LV geometry, and EF were measured. Results All patients survived AVR and underwent CMR 4 serial CMR's. LVMI markedly decreased by 6 months (157 ± 42 to 134 ± 32 g/m2, p 2. Similarly, EF increased pre to post-AVR (55 ± 22 to 65 ± 11%,(p 2. LV stroke volume increased rapidly from pre to post-AVR (40 ± 11 to 44 ± 7 ml, p Conclusion After initial beneficial effects imparted by AVR in severe AS patients, there are, as expected, marked improvements in LV reverse remodeling. Via CMR, surgically induced benefits to LV structure and function are durable and, unexpectedly express continued, albeit markedly incomplete improvement through 4 years post-AVR concordant with sustained improved clinical status. This supports down-regulation of both mRNA and MMP activity acutely with robust suppression long term.

Stress wave focusing transducers

Energy Technology Data Exchange (ETDEWEB)

Visuri, S.R., LLNL

1998-05-15

Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

No Evidence of XMRV or MuLV Sequences in Prostate Cancer, Diffuse Large B-Cell Lymphoma, or the UK Blood Donor Population

Directory of Open Access Journals (Sweden)

Mark James Robinson

2011-01-01

Full Text Available Xenotropic murine leukaemia virus-related virus (XMRV is a recently described retrovirus which has been claimed to infect humans and cause associated pathology. Initially identified in the US in patients with prostate cancer and subsequently in patients with chronic fatigue syndrome, doubt now exists that XMRV is a human pathogen. We studied the prevalence of genetic sequences of XMRV and related MuLV sequences in human prostate cancer, from B cell lymphoma patients and from UK blood donors. Nucleic acid was extracted from fresh prostate tissue biopsies, formalin-fixed paraffin-embedded (FFPE prostate tissue and FFPE B-cell lymphoma. The presence of XMRV-specific LTR or MuLV generic gag-like sequences was investigated by nested PCR. To control for mouse DNA contamination, a PCR that detected intracisternal A-type particle (IAP sequences was included. In addition, DNA and RNA were extracted from whole blood taken from UK blood donors and screened for XMRV sequences by real-time PCR. XMRV or MuLV-like sequences were not amplified from tissue samples. Occasionally MuLV gag and XMRV-LTR sequences were amplified from Indian prostate cancer samples, but were always detected in conjunction with contaminating murine genomic DNA. We found no evidence of XMRV or MuLV infection in the UK blood donors.

Design optimization of embedded ultrasonic transducers for concrete structures assessment.

Science.gov (United States)

Dumoulin, Cédric; Deraemaeker, Arnaud

2017-08-01

In the last decades, the field of structural health monitoring and damage detection has been intensively explored. Active vibration techniques allow to excite structures at high frequency vibrations which are sensitive to small damage. Piezoelectric PZT transducers are perfect candidates for such testing due to their small size, low cost and large bandwidth. Current ultrasonic systems are based on external piezoelectric transducers which need to be placed on two faces of the concrete specimen. The limited accessibility of in-service structures makes such an arrangement often impractical. An alternative is to embed permanently low-cost transducers inside the structure. Such types of transducers have been applied successfully for the in-situ estimation of the P-wave velocity in fresh concrete, and for crack monitoring. Up to now, the design of such transducers was essentially based on trial and error, or in a few cases, on the limitation of the acoustic impedance mismatch between the PZT and concrete. In the present study, we explore the working principles of embedded piezoelectric transducers which are found to be significantly different from external transducers. One of the major challenges concerning embedded transducers is to produce very low cost transducers. We show that a practical way to achieve this imperative is to consider the radial mode of actuation of bulk PZT elements. This is done by developing a simple finite element model of a piezoelectric transducer embedded in an infinite medium. The model is coupled with a multi-objective genetic algorithm which is used to design specific ultrasonic embedded transducers both for hard and fresh concrete monitoring. The results show the efficiency of the approach and a few designs are proposed which are optimal for hard concrete, fresh concrete, or both, in a given frequency band of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

Design and Development of transducer for IR radiation measurement

International Nuclear Information System (INIS)

Pattarachindanuwong, Surat; Poopat, Bovornchoke; Meethong, Wachira

2003-06-01

Recently, IR radiation has many important roles such as for plastics industry, food industry and medical instrumentation. The consequence of exposed irradiation objects from IR can be greatly affected by the quantity of IR radiation. Therefore the objectively this research is to design and develop a transducer for IR radiation measurement. By using a quartz halogen lamp as a IR heat source of IR radiation and a thermopile sensor as a transducer. The thermal conductivity of transducer and air flow, were also considered for design and development of transducer. The study shows that the designed transducer can be used and applied in high temperature process, for example, the quality control of welding, the non-contact temperature measurement of drying oven and the testing of IR source in medical therapy device

Effects of Benzalkonium Chloride, Proxel LV, P3 Hypochloran, Triton X-100 and DOWFAX 63N10 on anaerobic digestion processes

DEFF Research Database (Denmark)

Flores, German Antonio Enriquez; Fotidis, Ioannis; Karakashev, Dimitar Borisov

2015-01-01

In this study, the individual and synergistic toxicity of the following xenobiotics: Benzalkonium Chloride (BKC), Proxel LV (PRX), P3 Hypochloran (HPC), Triton X-100 (TRX), and DOWFAX 63N10 (DWF), on anaerobic digestion (AD) process, was assessed. The experiments were performed in batch and conti......In this study, the individual and synergistic toxicity of the following xenobiotics: Benzalkonium Chloride (BKC), Proxel LV (PRX), P3 Hypochloran (HPC), Triton X-100 (TRX), and DOWFAX 63N10 (DWF), on anaerobic digestion (AD) process, was assessed. The experiments were performed in batch...... and continuous (up-flow anaerobic sludge blanket, UASB) reactors with biochemical-industrial wastewater, as substrate. In batch experiments, half-maximal inhibitory concentrations (IC50) for the tested xenobiotics were found to be 13.1, 1003, 311.5 and 24.3 mg L1 for BKC, PRX, DWF and TRX, respectively while HPC...... observed from the batch reactors. Oppositely, TRX showed no inhibition in continuous mode, while inhibition was detected at batch mode....

Piezoelectric Polymer Ultrasound Transducers and Its Biomedical Applications

Energy Technology Data Exchange (ETDEWEB)

Ha, Kang Lyeol; Cao, Yanggang [Department of Physics, Pukyong National University, Busan (Korea, Republic of)

2012-10-15

PVDF(poly vinylidene fluoride) and P(VDF-TrFE)(poly vinylidene fluoride-tetrafluoroethylene) are the typical piezoelectric polymers with unique properties. Even they are inferior to conventional piezoelectric ceramics PZT in electromechanical conversion efficiency and interior loss, though they are superior in receiving sensitivity and frequency bandwidth. Their acoustic impedances are relatively close to water or biological tissue and it is easier to make thin film than other piezoelectric materials. Furthermore, the film is so flexible that it is easy to attach on a complex surface. Those properties are suitable for the ultrasound transducers which are useful for medical and biological application, so that various types of polymer transducers have been developed. In this paper, several important considerations for design and fabrication of piezoelectric polymer transducers were described and their effect on the transducer performance were demonstrated through the KLM model analysis. Then, it was briefly reviewed about the structures of the polymer transducers developed for obtaining images as well as the characteristics of the images in several important medical and biological application fields.

Receive-Noise Analysis of Capacitive Micromachined Ultrasonic Transducers.

Science.gov (United States)

Bozkurt, Ayhan; Yaralioglu, G Goksenin

2016-11-01

This paper presents an analysis of thermal (Johnson) noise received from the radiation medium by otherwise noiseless capacitive micromachined ultrasonic transducer (CMUT) membranes operating in their fundamental resonance mode. Determination of thermal noise received by multiple numbers of transducers or a transducer array requires the assessment of cross-coupling through the radiation medium, as well as the self-radiation impedance of the individual transducer. We show that the total thermal noise received by the cells of a CMUT has insignificant correlation, and is independent of the radiation impedance, but is only determined by the mass of each membrane and the electromechanical transformer ratio. The proof is based on the analytical derivations for a simple transducer with two cells, and extended to transducers with numerous cells using circuit simulators. We used a first-order model, which incorporates the fundamental resonance of the CMUT. Noise power is calculated by integrating over the entire spectrum; hence, the presented figures are an upper bound for the noise. The presented analyses are valid for a transimpedance amplifier in the receive path. We use the analysis results to calculate the minimum detectable pressure of a CMUT. We also provide an analysis based on the experimental data to show that output noise power is limited by and comparable to the theoretical upper limit.

Research and development of in-core transducers at the CIAE

International Nuclear Information System (INIS)

Huang Yucai; Liu Yupu; Jia Guozhen; Liu Lianping

1996-01-01

In this paper, R and D of in-core transducers at the CIAE are briefly summarized. With the construction and commissioning of PWR nuclear power plant in China, fuel rod behaviour need to be studied carefully. As conventional transducers cannot meet the requirements of in-core applications, R and D of in-core transducers are developed. Since 1980's, several kinds of in-core transducers have been successfully fabricated and tested under the conditions simulating PWR. At present, in-pile tests of the transducers combining with the studies of individual behaviour of PWR fuel rod are being planned at the CIAE. (author). 11 refs, 12 figs, 4 tabs

Influence of Installation Errors On the Output Data of the Piezoelectric Vibrations Transducers

Science.gov (United States)

Kozuch, Barbara; Chelmecki, Jaroslaw; Tatara, Tadeusz

2017-10-01

The paper examines an influence of installation errors of the piezoelectric vibrations transducers on the output data. PCB Piezotronics piezoelectric accelerometers were used to perform calibrations by comparison. The measurements were performed with TMS 9155 Calibration Workstation version 5.4.0 at frequency in the range of 5Hz - 2000Hz. Accelerometers were fixed on the calibration station in a so-called back-to-back configuration in accordance with the applicable international standard - ISO 16063-21: Methods for the calibration of vibration and shock transducers - Part 21: Vibration calibration by comparison to a reference transducer. The first accelerometer was calibrated by suitable methods with traceability to a primary reference transducer. Each subsequent calibration was performed when changing one setting in relation to the original calibration. The alterations were related to negligence and failures in relation to the above-mentioned standards and operating guidelines - e.g. the sensor was not tightened or appropriate substance was not placed. Also, there was modified the method of connection which was in the standards requirements. Different kind of wax, light oil, grease and other assembly methods were used. The aim of the study was to verify the significance of standards requirements and to estimate of their validity. The authors also wanted to highlight the most significant calibration errors. Moreover, relation between various appropriate methods of the connection was demonstrated.

Routine Ultrasound Quality Assurance in a Multi-Unit Radiology Department: A Retrospective Evaluation of Transducer Failures.

Science.gov (United States)

Vitikainen, Anne-Mari; Peltonen, Juha I; Vartiainen, Eija

2017-09-01

The importance of quality assurance (QA) in medical ultrasound (US) has been widely recognized and recommendations concerning technical QA have been published over the years. However, the demonstrated impact of a properly working QA protocol on clinical routine has been scarce. We investigated the transducer write-off causes for a 5-y period in a multi-unit radiology department with an annual average of 230 transducers in demanding diagnostic use. The transducer faults and the initial observers of the faults leading to transducer write-offs were traced and categorized. The most common cause of transducer write-off was an image uniformity problem or element failure. Mechanical faults or excessive leakage current and defects in the lens constituted smaller yet substantial shares. Our results suggest that a properly working routine QA program can detect majority of the faults before they are reported by users. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Performance of Honeywell silicon pressure transducers

Digital Repository Service at National Institute of Oceanography (India)

VijayKumar, K.; Joseph, A.; Desai, R.G.P.; Nagvekar, S.; Prabhudesai, S.; Damodaran, V.

pressure. The precision pressure transducer – ruggedized (PPTR) manufactured by Honeywell is provided with a special “Hastelloy” material isolation-diaphragm to protect the transducer port against corrosive effects during its prolonged exposure...-scale output (an intelligent technique anufacturers to hide the non-linearity of the product at all data points below ore realistic estimate of linearity is obtained by ean of a few samples) based on the corresponding true ethod employed by performance...

Damage detection in concrete structures with smart piezoceramic transducers

Science.gov (United States)

Naidu, Akshay S. K.; Bhalla, Suresh

2003-10-01

Detection of damages and progressive deterioration in structures is a critical issue. Visual inspections are tedious and unreliable. Incipient damages are often not discernible by low frequency dynamic response and other NDE techniques. Smart piezoelectric ceramic (PZT) transducers are emerging as an effective alternative in health monitoring of structures. The electro-mechanical impedance method employs the self-actuating and sensing characteristics of the PZT, without having to use actuators and sensors separately. When excited by an ac source, the PZT transducers bonded to the host structure activates the higher modes of vibration locally. Changes in the admittance response of the transducer serves as an indicator of damage around the transducer. In this paper, the effectiveness of PZT transducers for characterizing damages in concrete, in terms of the damage extent and location, is experimentally examined. The root mean square deviation (RMSD) index, adopted to quantify the changes in the admittance signatures, correlates with the damage extent. The damages on the surface that is not mounted by the PZT are also discernible. An array of transducers proves effective in detecting the damaged zone. The progressive incipient crack can be detected much before it actually becomes visible to the naked eye.

Agent-based unified approach for thermal and voltage constraint management in LV distribution network

NARCIS (Netherlands)

Haque, A.N.M.M.; Nguyen, H.P.; Vo, T.; Bliek, F.W.

2016-01-01

Rapid proliferation of the distributed energy resources (DERs) poses operational challenges for the low-voltage (LV) distribution networks in terms of thermal overloading of the network assets along with voltage limit violations at the connection points. A number of market-based and direct control

Study on electrical impedance matching for broadband ultrasonic transducer

Energy Technology Data Exchange (ETDEWEB)

Kim, Geon Woo [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Ki Bok [Korea Research Institute of Standards and Science, Center for Safety Measurement, Daejeon (Korea, Republic of); Baek, Kwang Sae [Elache Co., Busan (Korea, Republic of)

2017-02-15

Ultrasonic transducers with high resolution and resonant frequency are required to detect small defects (less than hundreds of μm) by ultrasonic testing. The resonance frequency and resolution of an ultrasonic transducer are closely related to the thickness of piezo-electric materials, backing materials, and the electric impedance matching technique. Among these factors, electrical impedance matching plays an important role because it can reduce the loss and reflection of ultrasonic energy differences in electrical impedance between an ultrasonic transducer and an ultrasonic defects detecting system. An LC matching circuit is the most frequently used electric matching method. It is necessary for the electrical impedance of an ultrasonic transducer to correspond to approximately 50 Ω to compensate the difference in electrical impedance between both connections. In this study, a 15 MHz immersion ultrasonic transducer was fabricated and an LC electrical impedance circuit was applied to that for having broad-band frequency characteristic.

Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration

International Nuclear Information System (INIS)

Lin Shuyu; Tian Hua

2008-01-01

A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed

Features calibration of the dynamic force transducers

Science.gov (United States)

Sc., M. Yu Prilepko D.; Lysenko, V. G.

2018-04-01

The article discusses calibration methods of dynamic forces measuring instruments. The relevance of work is dictated by need to valid definition of the dynamic forces transducers metrological characteristics taking into account their intended application. The aim of this work is choice justification of calibration method, which provides the definition dynamic forces transducers metrological characteristics under simulation operating conditions for determining suitability for using in accordance with its purpose. The following tasks are solved: the mathematical model and the main measurements equation of calibration dynamic forces transducers by load weight, the main budget uncertainty components of calibration are defined. The new method of dynamic forces transducers calibration with use the reference converter “force-deformation” based on the calibrated elastic element and measurement of his deformation by a laser interferometer is offered. The mathematical model and the main measurements equation of the offered method is constructed. It is shown that use of calibration method based on measurements by the laser interferometer of calibrated elastic element deformations allows to exclude or to considerably reduce the uncertainty budget components inherent to method of load weight.

Preoperative Chemoradiotherapy for Rectal Cancer: Randomized Trial Comparing Oral Uracil and Tegafur and Oral Leucovorin Vs. Intravenous 5-Fluorouracil and Leucovorin

International Nuclear Information System (INIS)

Torre, Alejandro de la; Garcia-Berrocal, Maria Isabel; Arias, Fernando; Marino, Alfonso; Valcarcel, Francisco; Magallon, Rosa; Regueiro, Carlos A.; Romero, Jesus; Zapata, Irma; Fuente, Cristina de la; Fernandez-Lizarbe, Eva; Vergara, Gloria; Belinchon, Belen; Veiras, Maria; Moleron, Rafael; Millan, Isabel

2008-01-01

Purpose: To compare, in a randomized trial, 5-fluorouracil (FU) plus leucovorin (LV) (FU+LV) vs. oral uracil and tegafur (UFT) plus LV (UFT+LV) given concomitantly with preoperative irradiation in patients with cT3-4 or N+ rectal cancer. Methods and Materials: A total of 155 patients were entered onto the trial. Patients received pelvic radiotherapy (4500-5,040 cGy in 5 to 6 weeks) and chemotherapy consisting of two 5-day courses of 20 mg/m 2 /d LV and 350 mg/m 2 /d FU in the first and fifth weeks of radiotherapy (77 patients) or one course of 25 mg/d oral LV and 300 mg/m 2 /d UFT for 4 weeks beginning in the second week of radiotherapy (78 patients). The primary endpoints were pathologic complete response (pCR) and resectability rate. Secondary endpoints included downstaging rate, toxicity, and survival. Results: Grade 3-5 acute hematologic toxicity occurred only with FU+LV (leukopenia 9%; p = 0.02). There were no differences in resectability rates (92.1% vs. 93.4%; p = 0.82). The pCR rate was 13.2% in both arms. Tumor downstaging was more frequent with UFT+LV (59.2% vs. 43.3%; p = 0.04). Three-year overall survival was 87% with FU+LV and 74% with UFT+LV (p = 0.37). The 3-year cumulative incidences of local recurrence were 7.5% and 8.9%, respectively (p = 0.619; relative risk, 1.46; 95% confidence interval 0.32-6.55). Conclusion: Although this study lacked statistical power to exclude clinically significant differences between both groups, the outcome of patients treated with UFT+LV did not differ significantly from that of patients treated with FU+LV, and hematologic toxicity was significantly lower in the experimental arm

Assessment of global and regional LV function obtained by quantitative gated SPECT using {sup 99m}Tc-tetrofosmin. Comparison with left ventricular cineangiography and echocardiography

Energy Technology Data Exchange (ETDEWEB)

Ban, Kazunobu; Nakajima, Toru; Aoki, Naoto; Abe, Sumihisa; Handa, Shunnosuke; Suzuki, Yutaka [Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine

1998-11-01

The quantitative gated SPECT (QGS) software that has automatic edge detection algorithm of the left ventricle, is able to calculate LV volumes and visualize LV wall motion with perfusion throughout the cardiac cycle. We evaluated the reliability of global and regional LV function derived from QGS using {sup 99m}Tc-tetrofosmin by comparing with left ventricular cineangiography (LVG) and echocardiography (ECHO). In 22 cardiac patients, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were calculated. Using cinematic display, regional LV wall motion were scored on a 3-point scale (1=normal, 2=hypokinesis, 3=akinesis; WMS). EDV, ESV and LVEF correlated well with those by LVG (p<0.001 for each). Correlation between WMS derived from QGS and ECHO was high (r=0.85, p<0.001). There was an inverse correlation between WMS and LVEF (r=0.77, p<0.001). In conclusion, QGS is useful to evaluate global LV function. Regional wall motion evaluated by QGS is good enough for clinical application. (author)

Low-intensity interval exercise training attenuates coronary vascular dysfunction and preserves Ca2+-sensitive K+ current in miniature swine with LV hypertrophy

Science.gov (United States)

Tharp, Darla L.; Ivey, Jan R.; Ganjam, Venkataseshu K.; Bowles, Douglas K.

2011-01-01

Coronary vascular dysfunction has been observed in several models of heart failure (HF). Recent evidence indicates that exercise training is beneficial for patients with HF, but the precise intensity and underlying mechanisms are unknown. Left ventricular (LV) hypertrophy can play a significant role in the development of HF; therefore, the purpose of this study was to assess the effects of low-intensity interval exercise training on coronary vascular function in sedentary (HF) and exercise trained (HF-TR) aortic-banded miniature swine displaying LV hypertrophy. Six months postsurgery, in vivo coronary vascular responses to endothelin-1 (ET-1) and adenosine were measured in the left anterior descending coronary artery. Baseline and maximal coronary vascular conductance were similar between all groups. ET-1-induced reductions in coronary vascular conductance (P < 0.05) were greater in HF vs. sedentary control and HF-TR groups. Pretreatment with the ET type A (ETA) receptor blocker BQ-123 prevented ET-1 hypersensitivity in HF animals. Whole cell voltage clamp was used to characterize composite K+ currents (IK+) in coronary smooth muscle cells. Raising internal Ca2+ from 200 to 500 nM increased Ca2+-sensitive K+ current in HF-TR and control, but not HF animals. In conclusion, an ETA-receptor-mediated hypersensitivity to ET-1, elevated resting LV wall tension, and decreased coronary smooth muscle cell Ca2+-sensitive IK+ was found in sedentary animals with LV hypertrophy. Low-intensity interval exercise training preserved normal coronary vascular function and smooth muscle cell Ca2+-sensitive IK+, illustrating a potential mechanism underlying coronary vascular dysfunction in a large-animal model of LV hypertrophy. Our results demonstrate the potential clinical impact of exercise on coronary vascular function in HF patients displaying pathological LV hypertrophy. PMID:21841018

Growth-hormone-induced signal transducer and activator of transcription 5 signaling causes gigantism, inflammation, and premature death but protects mice from aggressive liver cancer.

Science.gov (United States)

Friedbichler, Katrin; Themanns, Madeleine; Mueller, Kristina M; Schlederer, Michaela; Kornfeld, Jan-Wilhelm; Terracciano, Luigi M; Kozlov, Andrey V; Haindl, Susanne; Kenner, Lukas; Kolbe, Thomas; Mueller, Mathias; Snibson, Kenneth J; Heim, Markus H; Moriggl, Richard

2012-03-01

Persistently high levels of growth hormone (GH) can cause liver cancer. GH activates multiple signal-transduction pathways, among them janus kinase (JAK) 2-signal transducer and activator of transcription (STAT) 5 (signal transducer and activator of transcription 5). Both hyperactivation and deletion of STAT5 in hepatocytes have been implicated in the development of hepatocellular carcinoma (HCC); nevertheless, the role of STAT5 in the development of HCC as a result of high GH levels remains enigmatic. Thus, we crossed a mouse model of gigantism and inflammatory liver cancer caused by hyperactivated GH signaling (GH(tg) ) to mice with hepatic deletion of STAT5 (STAT5(Δhep) ). Unlike GH(tg) mice, GH(tg) STAT5(Δhep) animals did not display gigantism. Moreover, the premature mortality, which was associated with chronic inflammation, as well as the pathologic alterations of hepatocytes observed in GH(tg) mice, were not observed in GH(tg) animals lacking STAT5. Strikingly, loss of hepatic STAT5 proteins led to enhanced HCC development in GH(tg) mice. Despite reduced chronic inflammation, GH(tg) STAT5(Δhep) mice displayed earlier and more advanced HCC than GH(tg) animals. This may be attributed to the combination of increased peripheral lipolysis, hepatic lipid synthesis, loss of hepatoprotective mediators accompanied by aberrant activation of tumor-promoting c-JUN and STAT3 signaling cascades, and accumulation of DNA damage secondary to loss of cell-cycle control. Thus, HCC was never observed in STAT5(Δhep) mice. As a result of their hepatoprotective functions, STAT5 proteins prevent progressive fatty liver disease and the formation of aggressive HCC in the setting of hyperactivated GH signaling. At the same time, they play a key role in controlling systemic inflammation and regulating organ and body size. Copyright © 2011 American Association for the Study of Liver Diseases.

Performance comparison of 2-1-3, 1-3 and 1-3-2 piezoelectric composite transducers by finite element method

Directory of Open Access Journals (Sweden)

Y. Sun

2018-03-01

Full Text Available 1-3 type, 1-3-2 type and 2-1-3 type piezoelectric composites are three proper smart materials for the design and manufacture of ultrasonic transducers. They have been proposed in different stages but possess similar properties. Compared with the initial 1-3 type composite, 1-3-2 composite is of higher mechanical stability. Compared with 1-3-2 composite, 2-1-3 composite has lower manufacturing difficulty. In this paper, a comparative study on these three composites in terms of receiving transducer material properties is presented. Finite element method (FEM has been adopted to calculate longitudinal velocity, thickness electromechanical coupling coefficient and voltage receiving sensitivity. It is concluded that for a large aspect ratio α=1, the performance of 2-1-3 composite transducer is much better than that of 1-3 and 1-3-2 composite transducers. The thickness electromechanical coupling coefficient of 2-1-3 composite transducer is about 5.58 times that of 1-3 composite transducer and 7.42 times that of 1-3-2 composite transducer. The voltage receiving sensitivity at 2 kHz of 2-1-3 composite transducer is 13.1 dB higher than that of 1-3-2 composite transducer and 12.3 dB higher than that of 1-3 composite transducer.

Astakine LvAST binds to the β subunit of F1-ATP synthase and likely plays a role in white shrimp Litopeneaus vannamei defense against white spot syndrome virus.

Science.gov (United States)

Liang, Gao-Feng; Liang, Yan; Xue, Qinggang; Lu, Jin-Feng; Cheng, Jun-Jun; Huang, Jie

2015-03-01

Cytokines play a critical role in innate and adaptive immunity. Astakines represent a group of invertebrate cytokines that are related to vertebrate prokineticin and function in promoting hematopoiesis in crustaceans. We have identified an astakine from the white shrimp Litopeneaus vannamei and named it LvAST in a previous research. In the present research, we investigated the interactions among LvAST, the envelope protein VP37 of white spot syndrome virus (i.e., WSSV), and the β subunit of F1-ATP synthase (ATPsyn-β) of the white shrimp (i.e., BP53) using binding assays and co-precipitations. We also examined the effects of LvAST on shrimp susceptibility to WSSV. We found that LvAST and VP37 competitively bound to BP53, but did not bind to each other. Shrimps that had been injected with recombinant LvAST exhibited significantly lower mortality and longer survival time in experimental infections by WSSV. In contrast, shrimps whose LvAST gene expression had been inhibited by RNA interference showed significantly higher WSSV infection intensity and shorter survival time following viral challenges. These results suggested that LvAST and WSSV both likely use ATPsyn-β as a receptor and LvAST plays a role in shrimp defense against WSSV infection. This represented the first research showing the involvement of astakines in host antiviral immunity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sensitivity-Bandwidth Limit in a Multimode Optoelectromechanical Transducer

Science.gov (United States)

Moaddel Haghighi, I.; Malossi, N.; Natali, R.; Di Giuseppe, G.; Vitali, D.

2018-03-01

An optoelectromechanical system formed by a nanomembrane capacitively coupled to an L C resonator and to an optical interferometer has recently been employed for the highly sensitive optical readout of rf signals [T. Bagci et al., Nature (London) 507, 81 (2013), 10.1038/nature13029]. We propose and experimentally demonstrate how the bandwidth of such a transducer can be increased by controlling the interference between two electromechanical interaction pathways of a two-mode mechanical system. With a proof-of-principle device operating at room temperature, we achieve a sensitivity of 300 nV /√{Hz } over a bandwidth of 15 kHz in the presence of radio-frequency noise, and an optimal shot-noise-limited sensitivity of 10 nV /√{Hz } over a bandwidth of 5 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multimode transducer can achieve a bandwidth significantly larger than that for a single-mode one.

Analysis on Coupled Vibration of a Radially Polarized Piezoelectric Cylindrical Transducer

Directory of Open Access Journals (Sweden)

Jie Xu

2017-12-01

Full Text Available Coupled vibration of a radially polarized piezoelectric cylindrical transducer is analyzed with the mechanical coupling coefficient method. The method has been utilized to analyze the metal cylindrical transducer and the axially polarized piezoelectric cylindrical transducer. In this method, the mechanical coupling coefficient is introduced and defined as the stress ratio in different directions. Coupled vibration of the cylindrical transducer is regarded as the interaction of the plane radial vibration of a ring and the longitudinal vibration of a tube. For the radially polarized piezoelectric cylindrical transducer, the radial and longitudinal electric admittances as functions of mechanical coupling coefficients and angular frequencies are derived, respectively. The resonance frequency equations are obtained. The dependence of resonance frequency and mechanical coupling coefficient on aspect ratio is studied. Vibrational distributions on the surfaces of the cylindrical transducer are presented with experimental measurement. On the support of experiments, this work is verified and provides a theoretical foundation for the analysis and design of the radially polarized piezoelectric cylindrical transducer.

Creaming enhancement in a liter scale ultrasonic reactor at selected transducer configurations and frequencies.

Science.gov (United States)

Juliano, Pablo; Temmel, Sandra; Rout, Manoj; Swiergon, Piotr; Mawson, Raymond; Knoerzer, Kai

2013-01-01

Recent research has shown that high frequency ultrasound (0.4-3 MHz), can enhance milkfat separation in small scale systems able to treat only a few milliliters of sample. In this work, the effect of ultrasonic standing waves on milkfat creaming was studied in a 6L reactor and the influence of different frequencies and transducer configurations in direct contact with the fluid was investigated. A recombined coarse milk emulsion with fat globules stained with oil-red-O dye was selected for the separation trials. Runs were performed with one or two transducers placed in vertical (parallel or perpendicular) and horizontal positions (at the reactor base) at 0.4, 1 and/or 2 MHz (specific energy 8.5 ± 0.6 kJ/kg per transducer). Creaming behavior was assessed by measuring the thickness of the separated cream layer. Other methods supporting this assessment included the measurement of fat content, backscattering, particle size distribution, and microscopy of samples taken at the bottom and top of the reactor. Most efficient creaming was found after treatment at 0.4 MHz in single and double vertical transducer configurations. Among these configurations, a higher separation rate was obtained when sonicating at 0.4 MHz in a vertical perpendicular double transducer setup. The horizontal transducer configuration promoted creaming at 2 MHz only. Fat globule size increase was observed when creaming occurred. This research highlights the potential for enhanced separation of milkfat in larger scale systems from selected transducer configurations in contact with a dairy emulsion, or emulsion splitting in general. Copyright © 2012 Elsevier B.V. All rights reserved.

Interaction of a parametric transducer with a resonant bar gravitational radiation detector

International Nuclear Information System (INIS)

Linthorne, N.P.; Veitch, P.J.; Blair, D.G.

1990-01-01

It is shown that a microwave parametric transducer for a resonant bar gravitational radiation antenna can achieve high electromechanical coupling without degrading the acoustic Q of the antenna. The reactive coupling of the transducer to the antenna leads to both cold-damping and modification of the antenna's resonant frequency. These effects are examined in a 1.5 tonne niobium resonant bar antenna. At low coupling the observed behaviour is found to be in good agreement with theory. At higher coupling, the behaviour is complicated by other effects. We discuss how these parametric effects may be used to advantage when suitably controlled. (author)

A method for determining losses in magnetostrictive transducers

Science.gov (United States)

Krysin, V. N.; Ketlerov, A. S.

A method for estimating energy losses in magnetostrictive transducers is described. It is shown that domain remagnetization is responsible for the greatest energy loss in magnetostrictive transducers. Energy losses associated with Foucault currents and Joule heat are an order of magnitude less.

Multilevel inverter based class D audio amplifier for capacitive transducers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2014-01-01

The reduced semiconductor voltage stress makes the multilevel inverters especially interesting, when driving capacitive transducers for audio applications. A ± 300 V flying capacitor class D audio amplifier driving a 100 nF load in the midrange region of 0.1-3.5 kHz with Total Harmonic Distortion...

New improvement of the combined optical fiber transducer for landslide monitoring

Science.gov (United States)

Zhu, Z.-W.; Yuan, Q.-Y.; Liu, D.-Y.; Liu, B.; Liu, J.-C.; Luo, H.

2014-08-01

Landslide monitoring is important in predicting the behavior of landslides, thereby ensuring environmental, life, and property safety. On the basis of our previous studies, we conducted the double shear test by using a third-generation optical fiber transducer that uses expandable polystyrene (EPS) as base material. However, the third-generation transducer has poor performance when cohesive force is present between the grout and capillary stainless steel pipe of the transducer. Thus, the fourth-generation optical fiber transducer was invented. Similar to the third-generation transducer, the fourth-generation transducer also used EPS as its base material. Single shear test was conducted on the fourth-generation transducer after being grouted with cement mortar (1 : 1 mix ratio). The micro-bend loss mechanism of the optical fiber was considered, and the optical time domain reflectometry instrument was used. The fact that the loss sequence of optical fibers subjected to loading is different at various locations is found. The relationship of the loading-point displacement vs. optical fiber sliding distance and optical loss were measured. Results show that the maximum initial measurement precision of the newly proposed device is 1 mm, the corresponding sliding distance is 21 mm, and the dynamic range is 0-20 mm. The fourth-generation transducer can measure the movement direction of loadings, thus making this transducer applicable for landslide monitoring.

Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers

Directory of Open Access Journals (Sweden)

Tobias J. R. Eriksson

2016-08-01

Full Text Available Three designs for electrodynamic flexural transducers (EDFT for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio ( SNR ≃ 15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart.

DESIGN AND IMPLEMENTATION OF POTENTIOMETER-BASED NONLINEAR TRANSDUCER EMULATOR

Directory of Open Access Journals (Sweden)

Sheroz Khan

2011-05-01

Full Text Available This work attempts to design and implement in hardware a transducer with a nonlinear response using potentiometer. Potentiometer is regarded as a linear transducer, while a the response of a nonlinear transducer can be treated as a concatenation of linear segments made out of the response curve of an actual nonlinear transducer at the points of inflections being exhibited by the nonlinear curve. Each straight line segment is characterized by its slope and a constant, called the y-intercept, which is ultimately realized by a corresponding electronic circuit. The complete circuit diagram is made of three stages: (i the input stage for range selection, (ii a digital logic to make appropriate selection, (iii a conditioning circuit for realizing a given straight-line segment identified by its relevant slope and reference voltage. The simulation of the circuit is carried using MULTISIM, and the designed circuit is afterward tested to verify that variations of the input voltage give us an output voltage very close to the response pattern envisaged in the analytical stage of the design. The utility of this work lies in its applications in emulating purpose built transducers that could be used to nicely emulate a transducer in a real world system that is to be controlled by a programmable digital system.

Software for Correcting the Dynamic Error of Force Transducers

Directory of Open Access Journals (Sweden)

Naoki Miyashita

2014-07-01

Full Text Available Software which corrects the dynamic error of force transducers in impact force measurements using their own output signal has been developed. The software corrects the output waveform of the transducers using the output waveform itself, estimates its uncertainty and displays the results. In the experiment, the dynamic error of three transducers of the same model are evaluated using the Levitation Mass Method (LMM, in which the impact forces applied to the transducers are accurately determined as the inertial force of the moving part of the aerostatic linear bearing. The parameters for correcting the dynamic error are determined from the results of one set of impact measurements of one transducer. Then, the validity of the obtained parameters is evaluated using the results of the other sets of measurements of all the three transducers. The uncertainties in the uncorrected force and those in the corrected force are also estimated. If manufacturers determine the correction parameters for each model using the proposed method, and provide the software with the parameters corresponding to each model, then users can obtain the waveform corrected against dynamic error and its uncertainty. The present status and the future prospects of the developed software are discussed in this paper.

Piezoelectric transducer vibrations in a one-dimensional approximation

CERN Document Server

Hilke, H J

1973-01-01

The theory of piezoelectric transducer vibrations, which may be treated as one-dimensional, is developed in detail for thin discs vibrating in a pure thickness extensional mode. An effort has been made to obtain relations of general validity, which include losses, and which are in a simple explicit form convenient for practical calculations. The behaviour of transducers is discussed with special attention to their characteristics at the two fundamental frequencies, the so-called parallel and series resonances. Several peculiarities occur when transducers are coupled to media with considerably different acoustic impedances. These peculiarities are discussed and illustrated by numerical results for quartz and PZT 4 piezoelectric discs radiating into water, air and liquid hydrogen. The application of the theory to different types of vibrations is briefly illustrated for thin bars vibrating longitudinally. Short discussions are included on compound transducer systems, and on the properties of thin discs as receiv...

Development of a Flexible Broadband Rayleigh Waves Comb Transducer with Nonequidistant Comb Interval for Defect Detection of Thick-Walled Pipelines.

Science.gov (United States)

Zhao, Huamin; He, Cunfu; Yan, Lyu; Zhang, Haijun

2018-03-02

It is necessary to develop a transducer that can quickly detect the inner and outer wall defects of thick-walled pipes, in order to ensure the safety of such pipes. In this paper, a flexible broadband Rayleigh-waves comb transducer based on PZT (lead zirconate titanate) for defect detection of thick-walled pipes is studied. The multiple resonant coupling theory is used to expand the transducer broadband and the FEA (Finite Element Analysis) method is used to optimize transducer array element parameters. Optimization results show that the best array element parameters of the transducer are when the transducer array element length is 30 mm, the thickness is 1.2 mm, the width of one end of is 1.5 mm, and the other end is 3 mm. Based on the optimization results, such a transducer was fabricated and its performance was tested. The test results were consistent with the finite-element simulation results, and the -3 dB bandwidth of the transducer reached 417 kHz. Transducer directivity test results show that the Θ -3dB beam width was equal to 10 °, to meet the defect detection requirements. Finally, defects of thick-walled pipes were detected using the transducer. The results showed that the transducer could detect the inner and outer wall defects of thick-walled pipes within the bandwidth.

An adjustable multi-scale single beam acoustic tweezers based on ultrahigh frequency ultrasonic transducer.

Science.gov (United States)

Chen, Xiaoyang; Lam, Kwok Ho; Chen, Ruimin; Chen, Zeyu; Yu, Ping; Chen, Zhongping; Shung, K Kirk; Zhou, Qifa

2017-11-01

This paper reports the fabrication, characterization, and microparticle manipulation capability of an adjustable multi-scale single beam acoustic tweezers (SBAT) that is capable of flexibly changing the size of "tweezers" like ordinary metal tweezers with a single-element ultrahigh frequency (UHF) ultrasonic transducer. The measured resonant frequency of the developed transducer at 526 MHz is the highest frequency of piezoelectric single crystal based ultrasonic transducers ever reported. This focused UHF ultrasonic transducer exhibits a wide bandwidth (95.5% at -10 dB) due to high attenuation of high-frequency ultrasound wave, which allows the SBAT effectively excite with a wide range of excitation frequency from 150 to 400 MHz by using the "piezoelectric actuator" model. Through controlling the excitation frequency, the wavelength of ultrasound emitted from the SBAT can be changed to selectively manipulate a single microparticle of different sizes (3-100 μm) by using only one transducer. This concept of flexibly changing "tweezers" size is firstly introduced into the study of SBAT. At the same time, it was found that this incident ultrasound wavelength play an important role in lateral trapping and manipulation for microparticle of different sizes. Biotechnol. Bioeng. 2017;114: 2637-2647. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Turbine transducer developed for adverse conditions

International Nuclear Information System (INIS)

Cooper, D.R.; Edson, J.L.

1982-01-01

This paper reviews the latest developments that the Idaho National Engineering Laboratory (INEL) has made on a turbine transducer used in measurement of two-phase flow. It is operated in a modular configuration with a drag transducer to provide mass flow data. Current configurations allow its use in single modules or in multiples to provide flow profile information. The turbine can also provide mass flow data when used with associated instrumentation such as a densitometer. The transducer, which is the product of long investigations and test series, is subject to high vibration loading and high temperatures as well as a borated liquid environment; flow conditions range from all liquid to all steam and from ambient temperatures to over 600 0 F at pressures up to 2200 psi. Graphite bearing and carbide shaft materials were selected to provide corrosion resistance along with mechanical integrity, and resistance to wear. The new turbine design has met all operational requirements in actual use and in extended lifetime tests

Design of a Smart Ultrasonic Transducer for Interconnecting Machine Applications

Directory of Open Access Journals (Sweden)

Chang Xu

2009-06-01

Full Text Available A high-frequency ultrasonic transducer for copper or gold wire bonding has been designed, analyzed, prototyped and tested. Modeling techniques were used in the design phase and a practical design procedure was established and used. The transducer was decomposed into its elementary components. For each component, an initial design was obtained with simulations using a finite elements model (FEM. Simulated ultrasonic modules were built and characterized experimentally through the Laser Doppler Vibrometer (LDV and electrical resonance spectra. Compared with experimental data, the FEM could be iteratively adjusted and updated. Having achieved a remarkably highly-predictive FEM of the whole transducer, the design parameters could be tuned for the desired applications, then the transducer is fixed on the wire bonder with a complete holder clamping was calculated by the FEM. The approach to mount ultrasonic transducers on wire bonding machines also is of major importance for wire bonding in modern electronic packaging. The presented method can lead to obtaining a nearly complete decoupling clamper design of the transducer to the wire bonder.

Air-Coupled Piezoelectric Transducers with Active Polypropylene Foam Matching Layers

Directory of Open Access Journals (Sweden)

Tomás E. Gómez Alvarez-Arenas

2013-05-01

Full Text Available This work presents the design, construction and characterization of air-coupled piezoelectric transducers using 1–3 connectivity piezocomposite disks with a stack of matching layers being the outer one an active quarter wavelength layer made of polypropylene foam ferroelectret film. This kind of material has shown a stable piezoelectric response together with a very low acoustic impedance (<0.1 MRayl. These features make them a suitable candidate for the dual use or function proposed here: impedance matching layer and active material for air-coupled transduction. The transducer centre frequency is determined by the l/4 resonance of the polypropylene foam ferroelectret film (0.35 MHz, then, the rest of the transducer components (piezocomposite disk and passive intermediate matching layers are all tuned to this frequency. The transducer has been tested in several working modes including pulse-echo and pitch-catch as well as wide and narrow band excitation. The performance of the proposed novel transducer is compared with that of a conventional air-coupled transducers operating in a similar frequency range.

Thermal properties photonic crystal fiber transducers with ferromagnetic nanoparticles

Science.gov (United States)

Przybysz, N.; Marć, P.; Kisielewska, A.; Jaroszewicz, L. R.

2015-12-01

The main aim of the research is to design new types of fiber optic transducers based on filled photonic crystal fibers for sensor applications. In our research we propose to use as a filling material nanoparticles' ferrofluids (Fe3O4 NPs). Optical properties of such transducers are studied by measurements of spectral characteristics' changes when transducers are exposed to temperature and magnetic field changes. From synthesized ferrofluid several mixtures with different NPs' concentrations were prepared. Partially filled commercially available photonic crystal fiber LMA 10 (NKT Photonics) was used to design PCF transducers. Their thermo-optic properties were tested in a temperature chamber. Taking into account magnetic properties of synthetized NPs the patch cords based on a partially filled PM 1550 PCF were measured.

Development of Flexible Capacitive Ultrasound Transducers and the Use of Ultrasound for Bone Repair

Science.gov (United States)

Wentzell, Scott A.

Ultrasound is a widely applicable technique for therapy in the biomedical arena. However, conventional ultrasound transducers are not conducive for non-planar surfaces. Therefore, we developed flexible transducers capable of performing ultrasound and evaluated their use in biomedical applications. Flexible capacitive ultrasound transducers based on micrometer-thick dielectric tapes were developed and fabricated. These transducers were able to be made by hand at low-cost while still demonstrating good tolerances in center operating frequency. Intensities of up to 120 mW/cm2 were recorded and operation was dependent upon the applied AC and DC voltages along with the thickness of the dielectric insulation. These capacitive ultrasound transducers were used to stimulate MC3T3-E1 murine osteoblast cells to investigate the effects of low-frequency ultrasound on osteogenic gene expression and anabolic signaling pathways. After stimulation by 94.5 kHz continuous wave ultrasound for 20 minutes, significant increases in the activation of the Wnt signaling pathway and concentration of intracellular calcium were observed. Daily stimulation by ultrasound showed a trend of increased osteogenic gene expression across the phases of matrix deposition, maturation and calcification by osteoblasts. Finally, the heating of osteoblasts for stimulating osteoclastogenic responses was investigated. The application of increased temperatures of 42 and 47 degrees Celsius for 5 minutes showed significant increases in the RANKL/OPG ratio in media conditioned by osteoblasts. However, the altered RANKL/OPG ratio was not able to generate increases in osteoclastogenesis for RAW 264.7 murine macrophage cells culture in the condition media. This was possibly due to high overall osteoprotegerin expression, or unwanted inducement of M1 and M2 macrophage activation in the cell population. The overall work of this thesis demonstrates the development of novel capacitive transducers. These conformable

Performance Evaluation of Pressure Transducers for Water Impacts

Science.gov (United States)

Vassilakos, Gregory J.; Stegall, David E.; Treadway, Sean

2012-01-01

The Orion Multi-Purpose Crew Vehicle is being designed for water landings. In order to benchmark the ability of engineering tools to predict water landing loads, test programs are underway for scale model and full-scale water impacts. These test programs are predicated on the reliable measurement of impact pressure histories. Tests have been performed with a variety of pressure transducers from various manufacturers. Both piezoelectric and piezoresistive devices have been tested. Effects such as thermal shock, pinching of the transducer head, and flushness of the transducer mounting have been studied. Data acquisition issues such as sampling rate and anti-aliasing filtering also have been studied. The response of pressure transducers have been compared side-by-side on an impulse test rig and on a 20-inch diameter hemisphere dropped into a pool of water. The results have identified a range of viable configurations for pressure measurement dependent on the objectives of the test program.

Thermal effects on transducer material for heat assisted magnetic recording application

Energy Technology Data Exchange (ETDEWEB)

Ji, Rong, E-mail: Ji-Rong@dsi.a-star.edu.sg; Xu, Baoxi; Cen, Zhanhong; Ying, Ji Feng; Toh, Yeow Teck [Data Storage Institute, Agency for Science, Technology and Research (A-STAR), 5 Engineering Drive 1, Singapore 117608 (Singapore)

2015-05-07

Heat Assisted Magnetic Recording (HAMR) is a promising technology for next generation hard disk drives with significantly increased data recording capacities. In HAMR, an optical near-field transducer (NFT) is used to concentrate laser energy on a magnetic recording medium to fulfill the heat assist function. The key components of a NFT are transducer material, cladding material, and adhesion material between the cladding and the transducer materials. Since transducer materials and cladding materials have been widely reported, this paper focuses on the adhesion materials between the Au transducer and the Al{sub 2}O{sub 3} cladding material. A comparative study for two kinds of adhesion material, Ta and Cr, has been conducted. We found that Ta provides better thermal stability to the whole transducer than Cr. This is because after thermal annealing, chromium forms oxide material at interfaces and chromium atoms diffuse remarkably into the Au layer and react with Au to form Au alloy. This study also provides insights on the selection of adhesion material for HAMR transducer.

Determination of the response time of pressure transducers using the direct method

International Nuclear Information System (INIS)

Perillo, S.R.P.

1994-01-01

The available methods to determine the response time of nuclear safety related pressure transducers are discussed, with emphasis to the direct method. In order to perform the experiments, a Hydraulic Ramp Generator was built. The equipment produces ramp pressure transients simultaneously to a reference transducer and to the transducer under test. The time lag between the output of the two transducers, when they reach a predetermined setpoint, is measured as the time delay of the transducer under test. Some results using the direct method to determine the time delay of pressure transducers (1 E Class Conventional) are presented. (author). 18 refs, 35 figs, 12 tabs

Use of lambda pMu bacteriophages to isolate lambda specialized transducing bacteriophages carrying genes for bacterial chemotaxis.

Science.gov (United States)

Kondoh, H; Paul, B R; Howe, M M

1980-09-01

A general method for constructing lambda specialized transducing phages is described. The method, which is potentially applicable to any gene of Escherichia coli, is based on using Mu DNA homology to direct the integration of a lambda pMu phage near the genes whose transduction is desired. With this method we isolated a lambda transducing phage carrying all 10 genes in the che gene cluster (map location, 41.5 to 42.5 min). The products of the cheA and tar genes were identified by using transducing phages with amber mutations in these genes. It was established that tar codes for methyl-accepting chemotaxis protein II (molecular weight, 62,000) and that cheA codes for two polypeptides (molecular weights, 76,000 and 66,000). Possible origins of the two cheA polypeptides are discussed.

Design of compact piezoelectric transducers for shock wave applications

Science.gov (United States)

Dreyer, Thomas; Liebler, Marko; Riedlinger, Rainer E.; Ginter, Siegfried

2003-10-01

The application of focused intense sound pulses to treat several orthopedic diseases has gained in importance during the past years. Self-focusing piezoelectric transducers known from ESWL are not well suited for this purpose due to their size. Therefore compact transducers have to be designed. This implies an increase of the pressure pulse amplitude generated at the radiating surface. A stacked placement of two piezoelectric layers driven by two high-voltage pulses with an adjustable delay accomplishes this. Several designs are presented here representing transducers of different sizes. In principle piezoelectric transducers have the ability to vary the pressure pulse shape to a wider extent than other shock wave sources. Based on FEM simulations of the transducer the influence of some driving parameters, like a variation of the interpulse delay or shape of the driving voltage, on the resulting focal pressure signal is demonstrated. The results show the feasibility to control some parameters of the signal, for example the peak negative pressure amplitude. This possibility could provide new aspects in basic research as well as in clinical applications.

Polarization Control with Piezoelectric and LiNbO3 Transducers

Science.gov (United States)

Bradley, E.; Miles, E.; Loginov, B.; Vu, N.

Several Polarization control transducers have appeared on the market, and now automated, endless polarization control systems using these transducers are becoming available. Unfortunately it is not entirely clear what benchmark performance tests a polarization control system must pass, and the polarization disturbances a system must handle are open to some debate. We present quantitative measurements of realistic polarization disturbances and two benchmark tests we have successfully used to evaluate the performance of an automated, endless polarization control system. We use these tests to compare the performance of a system using piezoelectric transducers to that of a system using LiNbO3 transducers.

Electrical capacity and resistance determination of emitting electric transducer

International Nuclear Information System (INIS)

Alba Fernandez, J.; Ramis Soriano, J.

2000-01-01

In this work we calculate the electrical resistance and capacity of emitting electric transducer, which is mainly formed, in direct relationship with its properties, by a ceramic capacitor. Our aim is to motivate the students with an attractive element in order to carry out traditional measurements of the charge and discharge transients of a capacitor, implementing high resistance setups. (Author) 5 refs

2D array transducers for real-time 3D ultrasound guidance of interventional devices

Science.gov (United States)

Light, Edward D.; Smith, Stephen W.

2009-02-01

We describe catheter ring arrays for real-time 3D ultrasound guidance of devices such as vascular grafts, heart valves and vena cava filters. We have constructed several prototypes operating at 5 MHz and consisting of 54 elements using the W.L. Gore & Associates, Inc. micro-miniature ribbon cables. We have recently constructed a new transducer using a braided wiring technology from Precision Interconnect. This transducer consists of 54 elements at 4.8 MHz with pitch of 0.20 mm and typical -6 dB bandwidth of 22%. In all cases, the transducer and wiring assembly were integrated with an 11 French catheter of a Cook Medical deployment device for vena cava filters. Preliminary in vivo and in vitro testing is ongoing including simultaneous 3D ultrasound and x-ray fluoroscopy.

Partial LVAD restores ventricular outputs and normalizes LV but not RV stress distributions in the acutely failing heart in silico

OpenAIRE

Sack, Kevin L.; Baillargeon, Brian; Acevedo-Bolton, Gabriel; Genet, Martin; Rebelo, Nuno; Kuhl, Ellen; Klein, Liviu; Weiselthaler, Georg M.; Burkhoff, Daniel; Franz, Thomas; Guccione, Julius M.

2016-01-01

Purpose: Heart failure is a worldwide epidemic that is unlikely to change as the population ages and life expectancy increases. We sought to detail significant recent improvements to the Dassault Systèmes Living Heart Model (LHM) and use the LHM to compute left ventricular (LV) and right ventricular (RV) myofiber stress distributions under the following 4 conditions: (1) normal cardiac function; (2) acute left heart failure (ALHF); (3) ALHF treated using an LV assist device (LVAD) flow rate o...

Fabrication and comparison of PMN-PT single crystal, PZT and PZT-based 1-3 composite ultrasonic transducers for NDE applications.

Science.gov (United States)

Kim, Ki-Bok; Hsu, David K; Ahn, Bongyoung; Kim, Young-Gil; Barnard, Daniel J

2010-08-01

This paper describes fabrication and comparison of PMN-PT single crystal, PZT, and PZT-based 1-3 composite ultrasonic transducers for NDE applications. As a front matching layer between test material (Austenite stainless steel, SUS316) and piezoelectric materials, alumina ceramics was selected. The appropriate acoustic impedance of the backing materials for each transducer was determined based on the results of KLM model simulation. Prototype ultrasonic transducers with the center frequencies of approximately 2.25 and 5MHz for contact measurement were fabricated and compared to each other. The PMN-PT single crystal ultrasonic transducer shows considerably improved performance in sensitivity over the PZT and PZT-based 1-3 composite ultrasonic transducers. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Evolution of the Nova Vulpeculae no.1 1968 (LV Vul) spectrum after the maximum brightness

International Nuclear Information System (INIS)

Andrijya, I.; Antipova, L.I.; Babaev, M.B.; AN Azerbajdzhanskoj SSR, Baku. Shemakhinskaya Astrofizicheskaya Observatoriya)

1986-01-01

The analysis of the spectral evolution of LV Vulpeculae 1968 after the maximum brightness was carried out. It is shown that the pre-maximum spectrum was replaced by the principal one in less than 24sup(h). The diffuse enhanced scectrum and the Orion one existed already when the Nova brightness has decreased only by 0.4sup(m) and 0.5sup(m) respectively. The radial velocities of the Orion spectrum coincided with those of the diffuse enhanced one during the total observational period. The Orion spectrum consists of the lines of He I, N2, O 2 and may be H 1. The appearance of two additional components is probably due to splitting of the principal and diffuse enhanced spectrum

Immersion apparatus and process for an ultrasonic transducer in a liquid metal

International Nuclear Information System (INIS)

Le Baud, P.

1987-01-01

The ultrasonic transducer is introduced in a casing. The coupling zone of the transducer is covered by a layer of liquid metal. This layer is solidified and then the transducer with his coating layer is introduced in the liquid metal under an inert atmosphere. The device for immersing the transducer is claimed [fr

Mechano-electric optoisolator transducer with hysteresis

International Nuclear Information System (INIS)

Ciurus, I M; Dimian, M; Graur, A

2011-01-01

This article presents a theoretical and experimental study of designing a mechano-electric optoisolator transducer with hysteresis. Our research is centred upon designing transducers on the basis of optical sensors, as photoelectric conversions eliminate the influence of electromagnetic disturbances. Conversion of the rotation/translation motions into electric signals is performed with the help of a LED-photoresistor Polaroid optocoupler. The driver of the optocoupler's transmitter module is an independent current source. The signal conditioning circuit is a Schmitt trigger circuit. The device is designed to be applied in the field of automation and mechatronics.

Broadband electrical impedance matching for piezoelectric ultrasound transducers.

Science.gov (United States)

Huang, Haiying; Paramo, Daniel

2011-12-01

This paper presents a systematic method for designing broadband electrical impedance matching networks for piezoelectric ultrasound transducers. The design process involves three steps: 1) determine the equivalent circuit of the unmatched piezoelectric transducer based on its measured admittance; 2) design a set of impedance matching networks using a computerized Smith chart; and 3) establish the simulation model of the matched transducer to evaluate the gain and bandwidth of the impedance matching networks. The effectiveness of the presented approach is demonstrated through the design, implementation, and characterization of impedance matching networks for a broadband acoustic emission sensor. The impedance matching network improved the power of the acquired signal by 9 times.

Intravascular forward-looking ultrasound transducers for microbubble-mediated sonothrombolysis.

Science.gov (United States)

Kim, Jinwook; Lindsey, Brooks D; Chang, Wei-Yi; Dai, Xuming; Stavas, Joseph M; Dayton, Paul A; Jiang, Xiaoning

2017-06-14

Effective removal or dissolution of large blood clots remains a challenge in clinical treatment of acute thrombo-occlusive diseases. Here we report the development of an intravascular microbubble-mediated sonothrombolysis device for improving thrombolytic rate and thus minimizing the required dose of thrombolytic drugs. We hypothesize that a sub-megahertz, forward-looking ultrasound transducer with an integrated microbubble injection tube is more advantageous for efficient thrombolysis by enhancing cavitation-induced microstreaming than the conventional high-frequency, side-looking, catheter-mounted transducers. We developed custom miniaturized transducers and demonstrated that these transducers are able to generate sufficient pressure to induce cavitation of lipid-shelled microbubble contrast agents. Our technology demonstrates a thrombolysis rate of 0.7 ± 0.15 percent mass loss/min in vitro without any use of thrombolytic drugs.

Effective in vivo and ex vivo gene transfer to intestinal mucosa by VSV-G-pseudotyped lentiviral vectors

Directory of Open Access Journals (Sweden)

Kasahara Noriyuki

2010-05-01

Full Text Available Abstract Background Gene transfer to the gastrointestinal (GI mucosa is a therapeutic strategy which could prove particularly advantageous for treatment of various hereditary and acquired intestinal disorders, including inflammatory bowel disease (IBD, GI infections, and cancer. Methods We evaluated vesicular stomatitis virus glycoprotein envelope (VSV-G-pseudotyped lentiviral vectors (LV for efficacy of gene transfer to both murine rectosigmoid colon in vivo and human colon explants ex vivo. LV encoding beta-galactosidase (LV-β-Gal or firefly-luciferase (LV-fLuc reporter genes were administered by intrarectal instillation in mice, or applied topically for ex vivo transduction of human colorectal explant tissues from normal individuals. Macroscopic and histological evaluations were performed to assess any tissue damage or inflammation. Transduction efficiency and systemic biodistribution were evaluated by real-time quantitative PCR. LV-fLuc expression was evaluated by ex vivo bioluminescence imaging. LV-β-Gal expression and identity of transduced cell types were examined by histochemical and immunofluorescence staining. Results Imaging studies showed positive fLuc signals in murine distal colon; β-Gal-positive cells were found in both murine and human intestinal tissue. In the murine model, β-Gal-positive epithelial and lamina propria cells were found to express cytokeratin, CD45, and CD4. LV-transduced β-Gal-positive cells were also seen in human colorectal explants, consisting mainly of CD45, CD4, and CD11c-positive cells confined to the LP. Conclusions We have demonstrated the feasibility of LV-mediated gene transfer into colonic mucosa. We also identified differential patterns of mucosal gene transfer dependent on whether murine or human tissue was used. Within the limitations of the study, the LV did not appear to induce mucosal damage and were not distributed beyond the distal colon.

Estimation of Maximum Allowable PV Connection to LV Residential Power Networks

DEFF Research Database (Denmark)

Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

2011-01-01

Maximum photovoltaic (PV) hosting capacity of low voltage (LV) power networks is mainly restricted by either thermal limits of network components or grid voltage quality resulted from high penetration of distributed PV systems. This maximum hosting capacity may be lower than the available solar...... potential of geographic area due to power network limitations even though all rooftops are fully occupied with PV modules. Therefore, it becomes more of an issue to know what exactly limits higher PV penetration level and which solutions should be engaged efficiently such as over sizing distribution...

Voltage regulation in LV grids by coordinated volt-var control strategies

DEFF Research Database (Denmark)

Juamperez Goñi, Miguel Angel; Yang, Guangya; Kjær, Søren Bækhøj

2014-01-01

in a representative LV network in Bornholm Island using a multi-objective genetic algorithm. The approach is to increase the reactive power contribution of the inverters closest to the transformer during overvoltage conditions. Two standard reactive power control concepts, cosΦ(P) and Q(U), are simulated and compared...... in terms of network power losses and voltage level along the feeder. As a practical implementation, a reconfigurable hardware is used for developing a testing platform based on real-time measurements to regulate the reactive power level. The proposed testing platform has been developed within PVNET...

Characterisation and Modelling of MEMS Ultrasonic Transducers

International Nuclear Information System (INIS)

Teng, M F; Hariz, A J

2006-01-01

Silicon ultrasonic transducer micro arrays based on micro-electro-mechanicalsystem (MEMS) technologies are gaining popularity for applications in sonar sensing and excitation. A current challenge for many researchers is modelling the dynamic performance of these and other micro-mechanical devices to ascertain their performance and explain experimental observations reported. In this work, the performance simulation of a MEMS ultrasonic transducer array made from silicon nitride has been successfully carried out using CoventorWare package. The dynamic response of the entire transducer array was characterised, and the results were compared with theoretical predictions. Individual elements were found to vibrate with Bessel-like displacement patterns, and they were resonant at approximately 3 MHz, depending on thickness and lateral dimensions. The frequency shows a linear dependence around the common thickness of 2 μm. Peak displacement levels were examined as a function of frequency, DC bias voltage, and AC drive voltage. Accounting for fabrication variations, and uniformity variations across the wafer, the full array showed minimal variations in peak out-of-plane displacement levels across the device, and isolated elements that were over-responsive and under-responsive. Presently, the effect of observed variations across the array on the performance of the transducers and their radiated fields are being examined

Variability in effective radiating area and output power of new ultrasound transducers at 3 MHz.

Science.gov (United States)

Johns, Lennart D; Straub, Stephen J; Howard, Samuel M

2007-01-01

Spatial average intensity (SAI) is often used by clinicians to gauge therapeutic ultrasound dosage, yet SAI measures are not directly regulated by US Food and Drug Administration (FDA) standards. Current FDA guidelines permit a possible 50% to 150% minimum to maximum range of SAI values, potentially contributing to variability in clinical outcomes. To measure clinical values that describe ultrasound transducers and to determine the degree of intramanufacturer and intermanufacturer variability in effective radiating area, power, and SAI when the transducer is functioning at 3 MHz. A descriptive and interferential approach was taken to this quasi-experimental design. Measurement laboratory. Sixty-six 5-cm(2) ultrasound transducers were purchased from 6 different manufacturers. All transducers were calibrated and then assessed using standardized measurement techniques; SAI was normalized to account for variability in effective radiating area, resulting in an nSAI. Effective radiating area, power, and nSAI. All manufacturers with the exception of Omnisound (P = .534) showed a difference between the reported and measured effective radiating area values (P nSAI (P < .05) than all other manufacturers functioning at 3 MHz. Intramanufacturer variability in SAI ranged from 16% to 35%, and intermanufacturer variability ranged from 22% to 61%. Clinicians should consider treatment values of each individual transducer, regardless of the manufacturer. In addition, clinicians should scrutinize the power calibration and recalibration record of the transducer and adjust clinical settings as needed for the desired level of heating. Our data may aid in explaining the reported heating differences among transducers from different manufacturers. Stricter FDA standards regarding effective radiating area and total power are needed, and standards regulating SAI should be established.

Piezoelectric transducer array microspeaker

KAUST Repository

Carreno, Armando Arpys Arevalo; Conchouso Gonzalez, David; Castro, David; Kosel, Jü rgen; Foulds, Ian G.

2016-01-01

contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT

An ultrasonic therapeutic transducers using lead-free Na0.5K0.5NbO3-CuNb2O6 ceramics

International Nuclear Information System (INIS)

Yang, Ming-Ru; Chu, Sheng-Yuan; Tsai, Cheng-Che

2010-01-01

Research highlights: → In this paper, CN was added to NKN ceramics to decrease the sintering temperature and to improve the density and piezoelectric characteristics. The influence of CuNb 2 O 6 (CN) content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized samples was investigated. Results show that the samples synthesized with CN-doped not only improved the density but also exhibited superior piezoelectric characteristic, temperature stability of resonance frequency (TCF), and elastic stiffness coefficient than those of pure NKN piezoelectric ceramics. → The bulk density (4.47 g/cm 3 ), k p (40%), k t (45%), Q m (1642), C 33 D (19.64 x 10 10 N/m 2 ), TCF (-0.011%/ o C) and TCC (0.135%/ o C) values for NKN-01CN ceramics obtained from experiments show excellent 'hard' piezoelectric properties. Furthermore, a lead-free NKN-01CN ultrasonic therapeutic transducer was successfully driven by a self-tuning circuit. - Abstract: In this work, we reports on the CuNb 2 O 6 (CN) modified lead-free Na 0.5 K 0.5 NbO 3 (NKN) based piezoelectric ceramics were synthesized by solid-state reaction methods and sintered at 1075 o C for 3 h. A secondary phase of K 4 CuNb 8 O 23 was found in the XRD pattern of NKN-based ceramics as the CN dopants is 1 mol%. Microstructural analyses of un-doped and CN-doped ceramics were performed in a scanning electron microscope. The influence of CN content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized ceramics was investigated. The results show that the synthesized ceramics with CN-doped not only had improved density but also exhibited superior piezoelectric characteristics, temperature stability of resonance frequency (TCF), and a better elastic stiffness coefficient than those of pure NKN piezoelectric ceramics. The bulk density (4.47 g/cm 3 ), k p (40%), k t (45%), Q m (1642), C 33 D (19.64 x 10 10 N/m 2 ), TCF (-0

Analysis of a non-contact magnetoelastic torque transducer

International Nuclear Information System (INIS)

Andreescu, R.; Spellman, B.; Furlani, E.P.

2008-01-01

Results are presented for the performance of a magnetoelastic torque transducer that converts a torque-induced strain in a non-magnetic shaft into changes in a measurable magnetic field. The magnetic field is generated by a thin magnetostrictive layer that is coated onto the circumference of the shaft. The layer is magnetized and has an initial residual strain. The magnetization within the layer rotates in response to changes in the strain which occur when the shaft is torqued. The magnetic field produced by the layer changes with the magnetization and this can be sensed by a magnetometer to monitor the torque on the shaft. In this paper, a phenomenological theory is developed for predicting the performance of the transducer. The theory can be used to predict the magnetic field distribution of the transducer as a function of the physical properties of the magnetic coating, its residual strain, and the applied torque. It enables rapid parametric analysis of transducer performance, which is useful for the development and optimization of novel non-contact torque sensors

Instantaneous input electrical power measurements of HITU transducer

International Nuclear Information System (INIS)

Karaboece, B; Guelmez, Y; Rajagapol, S; Shaw, A

2011-01-01

HITU (High Intensity Theraupetic Ultrasound) transducers are widely used in therapeutic ultrasound in medicine. The output ultrasonic power of HITU transducer can be measured in number of methods described in IEC 61161 standard [1]. New IEC standards specifically for measurement of HITU equipment are under development. The ultrasound power radiated from a transducer is dependent on applied input electrical voltage and current and consequently power. But, up to now, no standardised method has been developed and adopted for the input electrical power measurements. Hence, a workpackage was carried out for the establishment of such method in the frequency range of 1 to 3 MHz as a part of EURAMET EMRP Era-net plus 'External Beam Cancer Therapy' project. Several current shunts were developed and evaluated. Current measurements were also realized with Philips current probe and preamplifier at NPL and Agilent current probe at UME. In this paper, a method for the measurement of instantaneous electrical power delivered to a reactive ultrasound transducer in the required frequency range is explored.

Instantaneous input electrical power measurements of HITU transducer

Energy Technology Data Exchange (ETDEWEB)

Karaboece, B; Guelmez, Y [Tuebitak Ulusal Metroloji Enstituesue (UME), P.K. 54 41470 Gebze-Kocaeli (Turkey); Rajagapol, S; Shaw, A, E-mail: baki.karaboce@ume.tubitak.gov.t [National Physical Laboratory (NPL), Hampton Road, Teddington TW11 0LW (United Kingdom)

2011-02-01

HITU (High Intensity Theraupetic Ultrasound) transducers are widely used in therapeutic ultrasound in medicine. The output ultrasonic power of HITU transducer can be measured in number of methods described in IEC 61161 standard [1]. New IEC standards specifically for measurement of HITU equipment are under development. The ultrasound power radiated from a transducer is dependent on applied input electrical voltage and current and consequently power. But, up to now, no standardised method has been developed and adopted for the input electrical power measurements. Hence, a workpackage was carried out for the establishment of such method in the frequency range of 1 to 3 MHz as a part of EURAMET EMRP Era-net plus 'External Beam Cancer Therapy' project. Several current shunts were developed and evaluated. Current measurements were also realized with Philips current probe and preamplifier at NPL and Agilent current probe at UME. In this paper, a method for the measurement of instantaneous electrical power delivered to a reactive ultrasound transducer in the required frequency range is explored.

USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

Science.gov (United States)

Weaver, H.L.; Campbell, G.S.

1985-01-01

Peltier coolers were modified and calibrated to serve as soil heat flux transducers. The modification was to fill their interiors with epoxy. The average calibration constant on 21 units was 13. 6 plus or minus 0. 8 kW m** minus **2 V** minus **1 at 20 degree C. This sensitivity is about eight times that of the two thermopile transducers with which comparisons were made. The thermal conductivity of the Peltier cooler transducers was 0. 4 W m** minus **1 degree C** minus **1, which is comparable to that of dry soil.

Reflective array modeling for reflective and directional SAW transducers.

Science.gov (United States)

Morgan, D P

1998-01-01

This paper presents a new approximate method for analyzing reflective SAW transducers, with much of the convenience of the coupled-mode (COM) method but with better accuracy. Transduction accuracy is obtained by incorporating the accurate electrostatic solution, giving for example correct harmonics, and allowance for electrode width variation, in a simple manner. Results are shown for a single-electrode transducer, Natural SPUDT and DART SPUDT, each using theoretically derived parameters. In contrast to the COM, the RAM can give accurate results for short or withdrawal-weighted transducers and for wide analysis bandwidth.

Transducer hygiene: comparison of procedures for decontamination of ultrasound transducers and their use in clinical practice.

Science.gov (United States)

Häggström, Mikael; Spira, Jack; Edelstam, Greta

2015-02-01

To determine whether current hygiene practices are appropriate during sonographic examinations. Five major hospitals in Sweden were investigated with a survey. At each hospital, the departments corresponding to the main types of sonographic examination were chosen. Personnel who were responsible for or acquainted with the local hygiene procedures completed a standardardized questionnaire. The surveys were completed by 25 departments, where the total number of sonographic examinations was approximately 20,000 per month. For transvaginal and transrectal sonographic examinations, the most common method for decontamination of the transducer was barrier protection during the procedure followed by cleansing with alcohol. Latex was the predominant cover material, but one department used polyethylene gloves, and another department used nitrile gloves. Both of these involved transvaginal ultrasonography. In transcutaneous examinations, all hospitals were using alcohol and paper or cloth for decontamination at a minimum. Transesophageal examinations were carried out without barrier protection, and decontamination was performed with an alkylating substance. The hygiene practices appear to be appropriate at most hospitals, but there is a prevalence of transducer cover materials of unacceptable permeability, as well as use of gloves on transducers despite insufficient evidence of safety. © 2015 Wiley Periodicals, Inc.

Manufacturing technologies for ultrasonic transducers in a broad frequency range

OpenAIRE

Gebhardt, Sylvia; Hohlfeld, Kai; Günther, Paul; Neubert, Holger

2018-01-01

According to the application field, working frequency of ultrasonic transducers needs to be tailored to a certain value. Low frequency ultrasonic transducers with working frequencies of 1 kHz to 1 MHz are especially interesting for sonar applications, whereas high frequency ultrasonic transducers with working frequencies higher than 15 MHz are favorable for high-resolution imaging in biomedical and non-destructive evaluation. Conventional non-destructive testing devices and clinical ultrasoun...

A theoretical study of cylindrical ultrasound transducers for intracavitary hyperthermia

International Nuclear Information System (INIS)

Lin, W.-L.; Fan, W.-C.; Yen, J.-Y.; Chen, Y.-Y.; Shieh, M.-J.

2000-01-01

Purpose: The purpose of this paper was to examine the heating patterns and penetration depth when a cylindrical ultrasound transducer is employed for intracavitary hyperthermia treatments. Methods and Materials: The present study employs a simulation program based on a simplified power deposition model for infinitely long cylindrical ultrasound transducers. The ultrasound power in the tissue is assumed to be exponentially attenuated according to the penetration depth of the ultrasound beam, and a uniform attenuation for the entire treatment region is also assumed. The distribution of specific absorption rate (SAR) ratio (the ratio of SAR for a point within the tissue to that for a specific point on the cavity surface) is used to determine the heating pattern for a set of given parameters. The parameters considered are the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity. Results: Simulation results show that the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity are the most influential parameters for the distribution of SAR ratio. A low frequency transducer located in a large cavity can produce a much better penetration. The cavity size is the major parameter affecting the penetration depth for a small cavity size, such as interstitial hyperthermia. The heating pattern can also be dramatically changed by the transducer eccentricity and radiating sector. In addition, for a finite length of cylindrical transducer, lower SAR ratio appears in the regions near the applicator's edges. Conclusion: The distribution of SAR ratio indicates the relationship between the treatable region and the parameters if an appropriate threshold of SAR ratio is taken. The findings of the present study comprehend whether or not a tumor is treatable, as well as select the optimal driving frequency, the appropriate cavity size, and the eccentricity of a cylindrical transducer for a specific treatment

Alpha-interferon does not increase the efficacy of 5-fluorouracil in advanced colorectal cancer.

LENUS (Irish Health Repository)

Thirion, P

2001-03-02

Two meta-analyses were conducted to quantify the benefit of combining alpha-IFN to 5FU in advanced colorectal cancer in terms of tumour response and survival. Analyses were based on a total of 3254 individual patient data provided by principal investigators of each trial. The meta-analysis of 5FU +\\/- LV vs. 5FU +\\/- LV + alpha-IFN combined 12 trials and 1766 patients. The meta-analysis failed to show any statistically significant difference between the two treatment groups in terms of tumour response or survival. Overall tumour response rates were 25% for patients receiving no alpha-IFN vs. 24% for patients receiving alpha-IFN (relative risk, RR = 1.02), and median survivals were 11.4 months for patients receiving no alpha-IFN vs. 11.5 months for patients receiving alpha-IFN (hazard ratio, HR = 0.95). The meta-analysis of 5FU + LV vs. 5FU + alpha-IFN combined 7 trials, and 1488 patients. This meta-analysis showed an advantage for 5FU + LV over 5FU + alpha-IFN which was statistically significant in terms of tumour response (23% vs. 18%; RR = 1.26;P = 0.042), and of a borderline significance for overall survival (HR = 1.11;P = 0.066). Metastases confined to the liver and primary rectal tumours were independent favourable prognostic factors for tumour response, whereas good performance status, metastases confined to the liver or confined to the lung, and primary tumour in the rectum were independent favourable prognostic factors for survival. We conclude that alpha-IFN does not increase the efficacy of 5FU or of 5FU + LV, and that 5FU + alpha-IFN is significantly inferior to 5FU + LV, for patients with advanced colorectal cancer.

A Force Transducer from a Junk Electronic Balance

Science.gov (United States)

Aguilar, Horacio Munguia; Aguilar, Francisco Armenta

2009-01-01

It is shown how the load cell from a junk electronic balance can be used as a force transducer for physics experiments. Recovering this device is not only an inexpensive way of getting a valuable laboratory tool but also very useful didactic work on electronic instrumentation. Some experiments on mechanics with this transducer are possible after a…

Design and analysis of fractional order seismic transducer for displacement and acceleration measurements

Science.gov (United States)

Veeraian, Parthasarathi; Gandhi, Uma; Mangalanathan, Umapathy

2018-04-01

Seismic transducers are widely used for measurement of displacement, velocity, and acceleration. This paper presents the design of seismic transducer in the fractional domain for the measurement of displacement and acceleration. The fractional order transfer function for seismic displacement and acceleration transducer are derived using Grünwald-Letnikov derivative. Frequency response analysis of fractional order seismic displacement transducer (FOSDT) and fractional order seismic acceleration transducer (FOSAT) are carried out for different damping ratio with the different fractional order, and the maximum dynamic measurement range is identified. The results demonstrate that fractional order seismic transducer has increased dynamic measurement range and less phase distortion as compared to the conventional seismic transducer even with a lower damping ratio. Time response of FOSDT and FOSAT are derived analytically in terms of Mittag-Leffler function, the effect of fractional behavior in the time domain is evaluated from the impulse and step response. The fractional order system is found to have significantly reduced overshoot as compared to the conventional transducer. The fractional order seismic transducer design proposed in this paper is illustrated with a design example for FOSDT and FOSAT. Finally, an electrical equivalent of FOSDT and FOSAT is considered, and its frequency response is found to be in close agreement with the proposed fractional order seismic transducer.

Multiple single-element transducer photoacoustic computed tomography system

Science.gov (United States)

Kalva, Sandeep Kumar; Hui, Zhe Zhi; Pramanik, Manojit

2018-02-01

Light absorption by the chromophores (hemoglobin, melanin, water etc.) present in any biological tissue results in local temperature rise. This rise in temperature results in generation of pressure waves due to the thermoelastic expansion of the tissue. In a circular scanning photoacoustic computed tomography (PACT) system, these pressure waves can be detected using a single-element ultrasound transducer (SUST) (while rotating in full 360° around the sample) or using a circular array transducer. SUST takes several minutes to acquire the PA data around the sample whereas the circular array transducer takes only a fraction of seconds. Hence, for real time imaging circular array transducers are preferred. However, these circular array transducers are custom made, expensive and not easily available in the market whereas SUSTs are cheap and readily available in the market. Using SUST for PACT systems is still cost effective. In order to reduce the scanning time to few seconds instead of using single SUST (rotating 360° ), multiple SUSTs can be used at the same time to acquire the PA data. This will reduce the scanning time by two-fold in case of two SUSTs (rotating 180° ) or by four-fold and eight-fold in case of four SUSTs (rotating 90° ) and eight SUSTs (rotating 45° ) respectively. Here we show that with multiple SUSTs, similar PA images (numerical and experimental phantom data) can be obtained as that of PA images obtained using single SUST.

High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer

Directory of Open Access Journals (Sweden)

Mihai Valentin Predoi

2014-01-01

Full Text Available Ultrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in which the real components of the transducer are modeled by finite elements. The classical model for longitudinal vibrations is not adequate because the generated longitudinal wave is not dispersive, the velocity being the same at any frequency. We have adopted the Rayleigh-Bishop model, which avoids these limitations, even if it is not converging to the first but to the second exact longitudinal mode in an elastic rod, as obtained from the complicated Pochhammer-Chree equations. Since real transducers have significant vibrations damping, we have introduced a damping term in the Rayleigh-Bishop model, increasing the imaginary part and keeping almost identical real part of the wavenumber. Common transducers produce amplitude modulated signals, completely attenuated after several periods. This can be modeled by two close frequencies, producing a “beat” phenomenon, superposed on the high damping. For this reason, we introduce a two-rod Rayleigh-Bishop model with damping. Agreement with measured normal velocity on the transducer free surface is encouraging for continuation of the research.

A mathematical model for transducer working at high temperature

International Nuclear Information System (INIS)

Fabre, J.P.

1974-01-01

A mathematical model is proposed for a lithium niobate piezoelectric transducer working at high temperature in liquid sodium. The model proposed suitably described the operation of the high temperature transducer presented; it allows the optimization of the efficiency and band-pass [fr

Calculations for piezoelectric ultrasonic transducers

International Nuclear Information System (INIS)

Jensen, H.

1986-05-01

Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a body which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation losses as well as internal losses may be important. Due to the complexity of the problem, a closed form solution is the exception rather than the rule. For this reason, it is necessary to use approximate methods for the analysis. Equivalent circuits, the Rayleigh-Ritz method, Mindlin plate theory and in particular the finite element method are considered. The finite element method is utilized for analysis of axisymmetric transducers. An explicit, fully piezoelectric, triangular ring element, with linear variations in displacement and electric potential is given. The influence of a fluid half-space is also given, in the form of a complex stiffness matrix. A special stacking procedure, for analysis of the backing has been developed. This procedure gives a saving, which is similar to that of the fast fourier transform algorithm, and is also wellsuited for analysis of finite and infinite waveguides. Results obtained by the finite element method are shown and compared with measurements and exact solutions. Good agreement is obtained. It is concluded that the finite element method can be a valueable tool in analysis and design of ultrasonic transducers. (author)

Numerical comparison of patch and sandwich piezoelectric transducers for transmitting ultrasonic waves

CSIR Research Space (South Africa)

Loveday, PW

2006-03-01

Full Text Available in the waveguide. Piezoelectric patch transducers are frequently employed, by researchers, for exciting waves in beam like structures. Sonar systems frequently make use of resonant transducers, such as sandwich transducers, for acoustic wave generation...

Optimization of ultrasonic tube testing with concentric transducers

International Nuclear Information System (INIS)

Dufayet, J.-P.; Gambin, Raymond.

1978-01-01

In order to test tubes by ultrasonics without rotation, concentric transducers can be used with conical mirrors to detect transverse defects and with helical shaped mirrors to detect longitudinal defects. Further optimization studies have been carried out in order to bring the system highly operational. The respective advantages brought by the rotating screen or by our especially designed sectorial transducers are discussed [fr

The inertial effect of acceleration fields on a self-decoupled wheel force transducer

Directory of Open Access Journals (Sweden)

Lihang Feng

Full Text Available AbstractWheel force transducer (WFT is a tool which can measure the three-axis forces and three-axis torques applied to the wheel in vehicle testing applications. However, the transducer is generally mounted on the wheel of a moving vehicle, when abruptly accelerating or braking, the mass/inertia of the transducer itself has extra effects on the sensor response so that inertia/mass loads will be detected and coupled into the signal outputs. This is the inertia coupling effect that decreases the sensor accuracy and should be avoided. In this paper, the inertia coupling problem induced by six dimensional accelerations is investigated for a universal WFT. Inertia load distribution of the WFT is solved based on the principle of equivalent mass and rotary inertia firstly, thus then its impact can be identified with the theoretical derivation. FEM simulation and experimental verification are performed as well. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear respectively. The relative errors are acceptable within less than 5% and the maximum impact of inertia loads on the signal output is about 1.5% in the measuring range.

Investigation of Calibrating Force Transducer Using Sinusoidal Force

International Nuclear Information System (INIS)

Zhang Li; Wang Yu; Zhang Lizhe

2010-01-01

Sinusoidal force calibration method was studied several years before at Physikalisch-Technische Bundesanstalt (PTB). A similar dynamic force calibration system is developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses electro-dynamic shakers to generate dynamic force in the range from 1 N to 20 kN, and heterodyne laser interferometers are used for acceleration measurement. The force transducer to be calibrated is mounted on the shaker, and a mass block is screwed on the top of force transducer, the sinusoidal forces realized by accelerated load masses are traceable to acceleration and mass according to the force definition. The methods of determining Spatial-dependent acceleration on mass block and measuring the end mass of force transducer in dynamic force calibration are discussed in this paper.

Positioning calibration apparatus for transducers employed in nuclear reactor vessel inspection apparatus

International Nuclear Information System (INIS)

Elsner, H.J.

1981-01-01

The invention provides a calibration apparatus suitable for verifying the position and orientation of transducers used in reactor vessel ultrasonic inspection. The apparatus includes moveable mounting means which secures a transducer within the tank in its normal inspection orientation. A drive is also provided for moving the transducer in the tank relative to a target. The target is slidably positioned in the tank at a distance from the transducer which is selected to avoid the distortion effects in the near field of the transducer. The drive mechanism may be provided with graduated indicia of travel, or a scale may be affixed to the side of the tank. (L.L.)

Design of a saturated analogue and digital current transducer

International Nuclear Information System (INIS)

Pross, Alexander

2002-01-01

This project describes the development of a new analogue and digital current transducer, providing a range of new theoretical design methods for these novel devices. The main control feature is the limit cycling operation, and the novel use of the embedded sigma-delta modulator sensor structure to derive a low component count digital sensor. The research programme was initiated into the design, development and evaluation of a novel non-Hall sensing analogue and digital current transducer. These transducers are used for measurement of high currents in power systems applications. The investigation is concerned with a new design which uses a magnetic ferrite core without an air gap for current measurement. The motivation for this work was to design a new control circuit which provides a low component count, and utilises the non-linear properties of the magnetic ferrite core to transmit direct current. The use of a limit cycle control circuit was believed to be particularly suitable for the analogue and digital transducers, for two main reasons: the low component count, and the output signal is directly digital. In line with the motivations outlined above, the outcome of the research has witnessed the design, development and evaluation of a practically realisable analogue and digital current transducer. The design procedure, which is documented in this thesis, is considered to be a major contribution to the field of transducers design and development using a control systems approach. Mathematical models for both analogue and digital transducers were developed and the resulting model based predictions were found to be in good agreement with measured results. Simplification of the new model sensing device was achieved by approximating the non-linear ferrite core using FFT analysis. This is also considered to be a significant contribution. The development analogue and digital current censors employed a sampled data control systems design and utilised limit cycling

Eddy Current Transducer Dedicated for Sigma Phase Evaluation in Duplex Stainless Steel

Directory of Open Access Journals (Sweden)

Grzegorz Psuj

2012-01-01

Full Text Available The paper describes a new transducer dedicated for evaluation of a duplex stainless steel (DSS. Different phases which exist in DSS have influence on mechanical as well as on electrical properties. Therefore, an eddy current transducer was utilized. In order to achieve high sensitivity, a differential type of the transducer was selected. The performance of the transducer was verified by utilizing the samples which had a different amount of sigma phase.

Piezoelectric textured ceramics: Effective properties and application to ultrasonic transducers.

Science.gov (United States)

Levassort, Franck; Pham Thi, Mai; Hemery, Henry; Marechal, Pierre; Tran-Huu-Hue, Louis-Pascal; Lethiecq, Marc

2006-12-22

Piezoelectric textured ceramics obtained by homo-template grain growth (HTGG) were recently demonstrated. A simple model with several assumptions has been used to calculate effective parameters of these new materials. Different connectivities have been simulated to show that spatial arrangements between the considered phases have little influence on the effective parameters, even through the 3-0 connectivity delivers the highest electromechanical thickness factor. A transducer based on a textured ceramic sample has been fabricated and characterised to show the efficiency of these piezoelectric materials. Finally, in a single element transducer configuration, simulation shows an improvement of 2 dB sensitivity for a transducer made with textured ceramic in comparison with a similar transducer design based on standard soft PZT (at equivalent bandwidths).

Full-scale Mark II CRT program: dynamic response evaluation test of pressure transducers

International Nuclear Information System (INIS)

Kukita, Yutaka; Namatame, Ken; Takeshita, Isao; Shiba, Masayoshi

1982-12-01

A dynamic response evaluation test of pressure transducers was conducted in support of the JAERI Full-Scale Mark II CRT (Containment Response Test) Program. The test results indicated that certain of the cavity-type transducers used in the early blowdown test had undesirable response characteristics. The transducer mounting scheme was modified to avoid trapping of air bubbles in the pressure transmission tubing attached to the transducers. The dynamic response of the modified transducers was acceptable within the frequency range of 200 Hz. (author)

Catheter-based high-intensity ultrasound for epicardial ablation of the left ventricle: device design and in vivo feasiblity

Science.gov (United States)

Salgaonkar, Vasant A.; Nazer, Babak; Jones, Peter D.; Tanaka, Yasuaki; Martin, Alastair; Ng, Bennett; Duggirala, Srikant; Diederich, Chris J.; Gerstenfeld, Edward P.

2015-03-01

The development and in vivo testing of a high-intensity ultrasound thermal ablation catheter for epicardial ablation of the left ventricle (LV) is presented. Scar tissue can occur in the mid-myocardial and epicardial space in patients with nonischemic cardiomyopathy and lead to ventricular tachycardia. Current ablation technology uses radiofrequency energy, which is limited epicardially by the presence of coronary vessels, phrenic nerves, and fat. Ultrasound energy can be precisely directed to deliver targeted deep epicardial ablation while sparing intervening epicardial nerve and vessels. The proof-of-concept ultrasound applicators were designed for sub-xyphoid access to the pericardial space through a steerable 14-Fr sheath. The catheter consists of two rectangular planar transducers, for therapy (6.4 MHz) and imaging (5 MHz), mounted at the tip of a 3.5-mm flexible nylon catheter coupled and encapsulated within a custom-shaped balloon for cooling. Thermal lesions were created in the LV in a swine (n = 10) model in vivo. The ultrasound applicator was positioned fluoroscopically. Its orientation and contact with the LV were verified using A-mode imaging and a radio-opaque marker. Ablations employed 60-s exposures at 15 - 30 W (electrical power). Histology indicated thermal coagulation and ablative lesions penetrating 8 - 12 mm into the left ventricle on lateral and anterior walls and along the left anterior descending artery. The transducer design enabled successful sparing from the epicardial surface to 2 - 4 mm of intervening ventricle tissue and epicardial fat. The feasibility of targeted epicardial ablation with catheter-based ultrasound was demonstrated.

Development and research of in-core transducers at IAE (Institute of Atomic Energy)

International Nuclear Information System (INIS)

Huang Yucai; Qian Shunfa; Jia Guozhen

1989-10-01

The development of in-core transducers at IAE (Institute of Atomic Energy) and their applications in in-pile fuel assembly test are mentioned. These transducers include mainly tubed tungsten-rhenium thermocouple assembly, displacement transducer of linear variable differential transformer, pressure transducer of membrane type, gamma thermometer, turbine flow meter, self-powered neutron detector etc

Candle soot nanoparticles-polydimethylsiloxane composites for laser ultrasound transducers

Science.gov (United States)

Chang, Wei-Yi; Huang, Wenbin; Kim, Jinwook; Li, Sibo; Jiang, Xiaoning

2015-10-01

Generation of high power laser ultrasound strongly demands the advanced materials with efficient laser energy absorption, fast thermal diffusion, and large thermoelastic expansion capabilities. In this study, candle soot nanoparticles-polydimethylsiloxane (CSNPs-PDMS) composite was investigated as the functional layer for an optoacoustic transducer with high-energy conversion efficiency. The mean diameter of the collected candle soot carbon nanoparticles is about 45 nm, and the light absorption ratio at 532 nm wavelength is up to 96.24%. The prototyped CSNPs-PDMS nano-composite laser ultrasound transducer was characterized and compared with transducers using Cr-PDMS, carbon black (CB)-PDMS, and carbon nano-fiber (CNFs)-PDMS composites, respectively. Energy conversion coefficient and -6 dB frequency bandwidth of the CSNPs-PDMS composite laser ultrasound transducer were measured to be 4.41 × 10-3 and 21 MHz, respectively. The unprecedented laser ultrasound transduction performance using CSNPs-PDMS nano-composites is promising for a broad range of ultrasound therapy applications.

Lithium niobate ultrasonic transducer design for Enhanced Oil Recovery.

Science.gov (United States)

Wang, Zhenjun; Xu, Yuanming; Gu, Yuting

2015-11-01

Due to the strong piezoelectric effect possessed by lithium niobate, a new idea that uses lithium niobate to design high-power ultrasonic transducer for Enhanced Oil Recovery technology is proposed. The purpose of this paper is to lay the foundation for the further research and development of high-power ultrasonic oil production technique. The main contents of this paper are as follows: firstly, structure design technique and application of a new high-power ultrasonic transducer are introduced; secondly, the experiment for reducing the viscosity of super heavy oil by this transducer is done, the optimum ultrasonic parameters for reducing the viscosity of super heavy oil are given. Experimental results show that heavy large molecules in super heavy oil can be cracked into light hydrocarbon substances under strong cavitation effect caused by high-intensity ultrasonic wave. Experiment proves that it is indeed feasible to design high-power ultrasonic transducer for ultrasonic oil production technology using lithium niobate. Copyright © 2015 Elsevier B.V. All rights reserved.

High Performance Relaxor-Based Ferroelectric Single Crystals for Ultrasonic Transducer Applications

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Yan Chen

2014-07-01

Full Text Available Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3O3-PbTiO3 (PMN-PT have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33~2000 pC/N, kt~60% near the morphotropic phase boundary (MPB. Ternary Pb(In1/2Nb1/2O3-Pb(Mg1/3Nb2/3O3-PbTiO3 (PIN-PMN-PT single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed.

Resonant transducers for solid-state plasma density modulation

Energy Technology Data Exchange (ETDEWEB)

Hallock, Gary A., E-mail: hallock@ece.utexas.edu [The University of Texas at Austin, Austin, Texas 78701 (United States); Meier, Mark A., E-mail: mark.a.meier@exxonmobil.com [ExxonMobil Upstream Research Company, Houston, Texas 77389 (United States)

2016-04-15

We have developed transducers capable of modulating the plasma density and plasma density gradients in indium antimonide. These transducers make use of piezoelectric drivers to excite acoustic pressure resonance at 3λ/2, generating large amplitude standing waves and plasma density modulations. The plasma density has been directly measured using a laser diagnostic. A layered media model shows good agreement with the experimental measurements.

Finite-State Complexity and the Size of Transducers

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Cristian Calude

2010-08-01

Full Text Available Finite-state complexity is a variant of algorithmic information theory obtained by replacing Turing machines with finite transducers. We consider the state-size of transducers needed for minimal descriptions of arbitrary strings and, as our main result, we show that the state-size hierarchy with respect to a standard encoding is infinite. We consider also hierarchies yielded by more general computable encodings.

Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

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Samuel Pichardo

Full Text Available Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13:135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode. The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d. resonance frequency of the samples was 465.1 (± 1.5 kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

Whole-genome sequence of Erysipelothrix larvae LV19(T) (=KCTC 33523(T)), a useful strain for arsenic detoxification, from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus.

Science.gov (United States)

Lim, Sooyeon; Rhee, Moon-Soo; Chang, Dong-Ho; Kim, Byoung-Chan

2016-04-10

Erysipelothrix larvae LV19(T) was preliminary isolated from the larval gut of a rhinoceros beetle, Trypoxylus dichotomus in Korea. Here, we present the whole genome sequence of E. larvae LV19(T) strain, which consisted of 2,511,486 base pairs with a GC content of 37.4% and one plasmid. Unlike other Erysipelothrix strains (SY 1027, Fujisawa and ATCC 19414), the arsenic-resistance genes were identified in LV19(T) strain. Copyright © 2016 Elsevier B.V. All rights reserved.

Research of Steel-dielectric Transition Using Subminiature Eddy-current Transducer

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Dmitriev, S. F.; Malikov, V. N.; Sagalakov, A. M.; Ishkov, A. V.

2018-05-01

The research aims to develop a subminiature transducer for electrical steel investigation. The authors determined the capability to study steel characteristics at different depths based on variations of eddy-current transducer amplitude at the steel-dielectric boundary. A subminiature transformer-type transducer was designed, which enables to perform local investigations of ferromagnetic materials using an eddy-current method based on local studies of the steel electrical conductivity. Having the designed transducer as a basis, a hardware-software complex was built to perform experimental studies of steel at the interface boundary. Test results are reported for a specimen with continuous and discrete measurements taken at different frequencies. The article provides the key technical information about the eddy current transformer used and describes the methodology of measurements that makes it possible to control steel to dielectric transition.

A flexible ultrasound transducer array with micro-machined bulk PZT.

Science.gov (United States)

Wang, Zhe; Xue, Qing-Tang; Chen, Yuan-Quan; Shu, Yi; Tian, He; Yang, Yi; Xie, Dan; Luo, Jian-Wen; Ren, Tian-Ling

2015-01-23

This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications.

A Flexible Ultrasound Transducer Array with Micro-Machined Bulk PZT

Directory of Open Access Journals (Sweden)

Zhe Wang

2015-01-01

Full Text Available This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications.

Low-intensity interval exercise training attenuates coronary vascular dysfunction and preserves Ca²⁺-sensitive K⁺ current in miniature swine with LV hypertrophy.

Science.gov (United States)

Emter, Craig A; Tharp, Darla L; Ivey, Jan R; Ganjam, Venkataseshu K; Bowles, Douglas K

2011-10-01

Coronary vascular dysfunction has been observed in several models of heart failure (HF). Recent evidence indicates that exercise training is beneficial for patients with HF, but the precise intensity and underlying mechanisms are unknown. Left ventricular (LV) hypertrophy can play a significant role in the development of HF; therefore, the purpose of this study was to assess the effects of low-intensity interval exercise training on coronary vascular function in sedentary (HF) and exercise trained (HF-TR) aortic-banded miniature swine displaying LV hypertrophy. Six months postsurgery, in vivo coronary vascular responses to endothelin-1 (ET-1) and adenosine were measured in the left anterior descending coronary artery. Baseline and maximal coronary vascular conductance were similar between all groups. ET-1-induced reductions in coronary vascular conductance (P < 0.05) were greater in HF vs. sedentary control and HF-TR groups. Pretreatment with the ET type A (ET(A)) receptor blocker BQ-123 prevented ET-1 hypersensitivity in HF animals. Whole cell voltage clamp was used to characterize composite K(+) currents (I(K(+))) in coronary smooth muscle cells. Raising internal Ca(2+) from 200 to 500 nM increased Ca(2+)-sensitive K(+) current in HF-TR and control, but not HF animals. In conclusion, an ET(A)-receptor-mediated hypersensitivity to ET-1, elevated resting LV wall tension, and decreased coronary smooth muscle cell Ca(2+)-sensitive I(K(+)) was found in sedentary animals with LV hypertrophy. Low-intensity interval exercise training preserved normal coronary vascular function and smooth muscle cell Ca(2+)-sensitive I(K(+)), illustrating a potential mechanism underlying coronary vascular dysfunction in a large-animal model of LV hypertrophy. Our results demonstrate the potential clinical impact of exercise on coronary vascular function in HF patients displaying pathological LV hypertrophy.

Extinction in the Galaxy from surface brightnesses of ESO-LV galaxies : Testing "standard" extinction maps

NARCIS (Netherlands)

Choloniewski, J.; Valentijn, E. A.

A new method for the determination of the extinction in the Galaxy is proposed. The method uses surface brightnesses of external galaxies in the B and R-bands. The observational data have been taken from the ESO-LV galaxy catalog. As a first application of our model we derive the ratio of R-band to

Improved sonothrombolysis from a modified diagnostic transducer delivering impulses containing a longer pulse duration.

Science.gov (United States)

Wu, Juefei; Xie, Feng; Kumar, Tanmay; Liu, Jinjin; Lof, John; Shi, William; Everbach, E Carr; Porter, Thomas R

2014-07-01

Although guided high-mechanical-index (MI) impulses from a diagnostic ultrasound transducer have been used in preclinical studies to dissolve coronary arterial and microvascular thrombi in the presence of intravenously infused microbubbles, it is possible that pulse durations (PDs) longer than that used for diagnostic imaging may further improve the effectiveness of this approach. By use of an established in vitro model flow system, a total of 90 occlusive porcine arterial thrombi (thrombus age: 3-4 h) within a vascular mimicking system were randomized to 10-min treatments with two different PDs (5 and 20 μs) using a Philips S5-1 transducer (1.6-MHz center frequency) at a range of MIs (from 0.2 to 1.4). All impulses were delivered in an intermittent fashion to permit microbubble replenishment within the thrombosed vessel. Diluted lipid-encapsulated microbubbles (0.5% Definity) were infused during the entire treatment period. A tissue-mimicking phantom 5 cm thick was placed between the transducer and thrombosed vessel to mimic transthoracic attenuation. Two 20-MHz passive cavitation detection systems were placed confocal to the insonified vessel to assess for inertial cavitational activity. Percentage thrombus dissolution was calculated by weighing the thrombi before and after each treatment. Percentage thrombus dissolution was significantly higher with a 20-μs PD already at the 0.2 and 0.4 MI therapeutic impulses (54 ± 12% vs. 33 ± 17% and 54 ± 22% vs. 34 ± 17%, p cavitation detection systems detected only low intensities of inertial cavitation. At higher MI settings and 20-μs PDs, percentage thrombus dissolution decreased most likely from high-intensity cavitation shielding of the thrombus. Slightly prolonging the PD on a diagnostic transducer improves the degree of sonothrombolysis that can be achieved without fibrinolytic agents at a lower mechanical index. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc

A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet.

Science.gov (United States)

Liu, Yingxiang; Liu, Junkao; Chen, Weishan; Shi, Shengjun

2012-05-01

A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet was proposed in this paper. The proposed motor contains a horizontal transducer and two vertical transducers. The horizontal transducer includes two exponential shape horns located at the leading ends, and each vertical transducer contains one exponential shape horn. The horns of the horizontal transducer and the vertical transducer intersect at the tip ends where the driving feet are located. Longitudinal vibrations are superimposed in the motor and generate elliptical motions at the driving feet. The two vibration modes of the motor are discussed, and the motion trajectories of driving feet are deduced. By adjusting the structural parameters, the resonance frequencies of two vibration modes were degenerated. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 854 mm/s and maximum thrust force of 40 N at a voltage of 200 V(rms).

Multiharmonic Frequency-Chirped Transducers for Surface-Acoustic-Wave Optomechanics

Science.gov (United States)

Weiß, Matthias; Hörner, Andreas L.; Zallo, Eugenio; Atkinson, Paola; Rastelli, Armando; Schmidt, Oliver G.; Wixforth, Achim; Krenner, Hubert J.

2018-01-01

Wide-passband interdigital transducers are employed to establish a stable phase lock between a train of laser pulses emitted by a mode-locked laser and a surface acoustic wave generated electrically by the transducer. The transducer design is based on a multiharmonic split-finger architecture for the excitation of a fundamental surface acoustic wave and a discrete number of its overtones. Simply by introducing a variation of the transducer's periodicity p , a frequency chirp is added. This combination results in wide frequency bands for each harmonic. The transducer's conversion efficiency from the electrical to the acoustic domain is characterized optomechanically using single quantum dots acting as nanoscale pressure sensors. The ability to generate surface acoustic waves over a wide band of frequencies enables advanced acousto-optic spectroscopy using mode-locked lasers with fixed repetition rate. Stable phase locking between the electrically generated acoustic wave and the train of laser pulses is confirmed by performing stroboscopic spectroscopy on a single quantum dot at a frequency of 320 MHz. Finally, the dynamic spectral modulation of the quantum dot is directly monitored in the time domain combining stable phase-locked optical excitation and time-correlated single-photon counting. The demonstrated scheme will be particularly useful for the experimental implementation of surface-acoustic-wave-driven quantum gates of optically addressable qubits or collective quantum states or for multicomponent Fourier synthesis of tailored nanomechanical waveforms.

Prognostic significance of signal transducer and activator of transcription 5 and 5b expression in Epstein-Barr virus-positive patients with chronic lymphocytic leukemia.

Science.gov (United States)

Diamantopoulos, Panagiotis T; Sofotasiou, Maria; Georgoussi, Zafiroula; Giannakopoulou, Nefeli; Papadopoulou, Vasiliki; Galanopoulos, Athanasios; Kontandreopoulou, Elina; Zervakis, Panagiotis; Pallaki, Paschalina; Kalala, Fani; Kyrtsonis, Marie-Christine; Dimitrakopoulou, Aglaia; Vassilakopoulos, Theodoros; Angelopoulou, Maria; Spanakis, Nikolaos; Viniou, Nora-Athina

2016-09-01

Signal transducer and activator of transcription (STAT) proteins have been intensively studied in hematologic malignancies, and the efficacy of agents against STATs in lymphomas is already under research. We investigated the expression of total STAT5 and STAT5b in peripheral blood samples of patients with chronic lymphocytic leukemia (CLL) in correlation with the presence of Epstein-Barr Virus (EBV) and its major oncoprotein (latent membrane protein 1, LMP1). The EBV load was measured in the peripheral blood by real-time PCR for the BXLF1 gene and the levels of LMP1 by PCR and ELISA. Western blotting was performed for total STAT5 and STAT5b in protein extracts. STAT5b was only expressed in patients (not in healthy subjects) and STAT5 but particularly STAT5b expression was correlated with the presence of the virus (77.3% vs. 51.2%, P = 0.006 for STAT5b) and to the expression of LMP1 (58.3% vs. 21.6%, P = 0.011 for STAT5b). Moreover, the expression of STAT5b and the presence of EBV and LMP1 were strongly negatively correlated with the overall survival of the patients (log-rank test P = 0.011, 0.015, 0.006, respectively). Double positive (for EBV and STAT5b) patients had the lowest overall survival (log-rank test P = 0.013). This is the first report of a survival disadvantage of EBV+ patients with CLL, and the first time that STAT5b expression is correlated with survival. The correlation of STAT5 expression with the presence of the virus, along with our survival correlations defines a subgroup of patients with CLL that may benefit from anti-STAT agents. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

77 FR 21620 - Notice of the Buy America Waiver Request for Vossloh 101-LV Concrete Ties

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2012-04-10

... the Buy America Waiver Request for Vossloh 101-LV Concrete Ties AGENCY: Federal Railroad... concrete ties, which contain certain components not manufactured in the United States. In furtherance of... concrete ties. FRA has received this request from the four States for the following projects: (a) The...

Microfluidic Transduction Harnesses Mass Transport Principles to Enhance Gene Transfer Efficiency.

Science.gov (United States)

Tran, Reginald; Myers, David R; Denning, Gabriela; Shields, Jordan E; Lytle, Allison M; Alrowais, Hommood; Qiu, Yongzhi; Sakurai, Yumiko; Li, William C; Brand, Oliver; Le Doux, Joseph M; Spencer, H Trent; Doering, Christopher B; Lam, Wilbur A

2017-10-04

Ex vivo gene therapy using lentiviral vectors (LVs) is a proven approach to treat and potentially cure many hematologic disorders and malignancies but remains stymied by cumbersome, cost-prohibitive, and scale-limited production processes that cannot meet the demands of current clinical protocols for widespread clinical utilization. However, limitations in LV manufacture coupled with inefficient transduction protocols requiring significant excess amounts of vector currently limit widespread implementation. Herein, we describe a microfluidic, mass transport-based approach that overcomes the diffusion limitations of current transduction platforms to enhance LV gene transfer kinetics and efficiency. This novel ex vivo LV transduction platform is flexible in design, easy to use, scalable, and compatible with standard cell transduction reagents and LV preparations. Using hematopoietic cell lines, primary human T cells, primary hematopoietic stem and progenitor cells (HSPCs) of both murine (Sca-1 + ) and human (CD34 + ) origin, microfluidic transduction using clinically processed LVs occurs up to 5-fold faster and requires as little as one-twentieth of LV. As an in vivo validation of the microfluidic-based transduction technology, HSPC gene therapy was performed in hemophilia A mice using limiting amounts of LV. Compared to the standard static well-based transduction protocols, only animals transplanted with microfluidic-transduced cells displayed clotting levels restored to normal. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Immune Algorithm Complex Method for Transducer Calibration

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YU Jiangming

2014-08-01

Full Text Available As a key link in engineering test tasks, the transducer calibration has significant influence on accuracy and reliability of test results. Because of unknown and complex nonlinear characteristics, conventional method can’t achieve satisfactory accuracy. An Immune algorithm complex modeling approach is proposed, and the simulated studies on the calibration of third multiple output transducers is made respectively by use of the developed complex modeling. The simulated and experimental results show that the Immune algorithm complex modeling approach can improve significantly calibration precision comparison with traditional calibration methods.

Resonant acoustic transducer system for a well drilling string

Science.gov (United States)

Nardi, Anthony P.

1981-01-01

For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.

Field deployable processing methods for stay-in-place ultrasonic transducers

Science.gov (United States)

Malarich, Nathan; Lissenden, Cliff J.; Tittmann, Bernhard R.

2018-04-01

Condition monitoring provides key data for managing the operation and maintenance of mechanical equipment in the power generation, chemical processing, and manufacturing industries. Ultrasonic transducers provide active monitoring capabilities by wall thickness measurements, elastic property determination, crack detection, and other means. In many cases the components operate in harsh environments that may include high temperature, radiation, and hazardous chemicals. Thus, it is desirable to have permanently affixed ultrasonic transducers for condition monitoring in harsh environments. Spray-on transducers provide direct coupling between the active element and the substrate, and can be applied to curved surfaces. We describe a deposition methodology for ultrasonic transducers that can be applied in the field. First, piezoceramic powders mixed into a sol-gel are air-spray deposited onto the substrate. Powder constituents are selected based on the service environment in which the condition monitoring will be performed. Then the deposited coating is pyrolyzed and partially densified using an induction heating system with a custom work coil designed to match the substrate geometry. The next step, applying the electrodes, is more challenging than might be expected because of the porosity of the piezoelectric coating and the potential reactivity of elements in the adjacent layers. After connecting lead wires to the electrodes the transducer is poled and a protective coating can be applied prior to use. Processing of a PZT-bismuth titanate transducer on a large steel substrate is described along with alternate methods.

Design of HIFU Transducers for Generating Specified Nonlinear Ultrasound Fields.

Science.gov (United States)

Rosnitskiy, Pavel B; Yuldashev, Petr V; Sapozhnikov, Oleg A; Maxwell, Adam D; Kreider, Wayne; Bailey, Michael R; Khokhlova, Vera A

2017-02-01

Various clinical applications of high-intensity focused ultrasound have different requirements for the pressure levels and degree of nonlinear waveform distortion at the focus. The goal of this paper is to determine transducer design parameters that produce either a specified shock amplitude in the focal waveform or specified peak pressures while still maintaining quasi-linear conditions at the focus. Multiparametric nonlinear modeling based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation with an equivalent source boundary condition was employed. Peak pressures, shock amplitudes at the focus, and corresponding source outputs were determined for different transducer geometries and levels of nonlinear distortion. The results are presented in terms of the parameters of an equivalent single-element spherically shaped transducer. The accuracy of the method and its applicability to cases of strongly focused transducers were validated by comparing the KZK modeling data with measurements and nonlinear full diffraction simulations for a single-element source and arrays with 7 and 256 elements. The results provide look-up data for evaluating nonlinear distortions at the focus of existing therapeutic systems as well as for guiding the design of new transducers that generate specified nonlinear fields.

Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium

Energy Technology Data Exchange (ETDEWEB)

Arpaia, P., E-mail: pasquale.arpaia@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Girone, M., E-mail: mario.girone@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Department of Engineering, University of Sannio, Benevento (Italy); Liccardo, A., E-mail: annalisa.liccardo@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Pezzetti, M., E-mail: marco.pezzetti@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Piccinelli, F., E-mail: fabio.piccinelli@cern.ch [Department of Mechanical Engineering, University of Brescia, Brescia (Italy)

2015-12-15

The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

Nonlinear Dynamic Modeling of Langevin-Type Piezoelectric Transducers

Directory of Open Access Journals (Sweden)

Nicolás Peréz Alvarez

2015-11-01

Full Text Available Langevin transducers are employed in several applications, such as power ultrasound systems, naval hydrophones, and high-displacement actuators. Nonlinear effects can influence their performance, especially at high vibration amplitude levels. These nonlinear effects produce variations in the resonant frequency, harmonics of the excitation frequency, in addition to loss of symmetry in the frequency response and “frequency domain hysteresis”. In this context, this paper presents a simplified nonlinear dynamic model of power ultrasound transducers requiring only two parameters for simulating the most relevant nonlinear effects. One parameter reproduces the changes in the resonance frequency and the other introduces the dependence of the frequency response on the history of the system. The piezoelectric constitutive equations are extended by a linear dependence of the elastic constant on the mechanical displacement amplitude. For introducing the frequency hysteresis, the elastic constant is computed by combining the current value of the mechanical amplitude with the previous state amplitude. The model developed in this work is applied for predicting the dynamic responses of a 26 kHz ultrasonic transducer. The comparison of theoretical and experimental responses, obtained at several input voltages around the tuned frequency, shows a good agreement, indicating that the model can accurately describe the transducer nonlinear behavior.

A capacitive ultrasonic transducer based on parametric resonance

Science.gov (United States)

Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F.

2017-07-01

A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of fo. When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2fo with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at fo frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

Actuatable capacitive transducer for quantitative nanoindentation combined with transmission electron microscopy

Science.gov (United States)

Warren, Oden L.; Asif, S. A. Syed; Cyrankowski, Edward; Kounev, Kalin

2010-09-21

An actuatable capacitive transducer including a transducer body, a first capacitor including a displaceable electrode and electrically configured as an electrostatic actuator, and a second capacitor including a displaceable electrode and electrically configured as a capacitive displacement sensor, wherein the second capacitor comprises a multi-plate capacitor. The actuatable capacitive transducer further includes a coupling shaft configured to mechanically couple the displaceable electrode of the first capacitor to the displaceable electrode of the second capacitor to form a displaceable electrode unit which is displaceable relative to the transducer body, and an electrically-conductive indenter mechanically coupled to the coupling shaft so as to be displaceable in unison with the displaceable electrode unit.-

Dynamic Mode Tuning of Ultrasonic Guided Wave Using an Array Transducer

International Nuclear Information System (INIS)

Kim, Young H.; Song, Sung J.; Park, Joon S.; Kim, Jae H.; Eom, Heung S.

2005-01-01

Ultrasonic guided waves have been widely employed for long range inspection of structures such as plates, rods and pipes. There are numerous modes with different wave velocities, and the appropriate mode selection is one of key techniques in the application of guided waves. In the present work, phase tuning by an array transducer was applied to generate ultrasonic guided waves. For this purpose, 8-channel ultrasonic pulser/receiver and their controller which enables sequential activation of each channels with given time delay were developed. Eight transducers were fabricated in order to generate guided waves by using an array transducer. The selective tuning of wave mode can be achieved by changing the interval between elements of an array transducer

Simplified production and concentration of HIV-1-based lentiviral vectors using HYPERFlask vessels and anion exchange membrane chromatography

Science.gov (United States)

Kutner, Robert H; Puthli, Sharon; Marino, Michael P; Reiser, Jakob

2009-01-01

Background During the past twelve years, lentiviral (LV) vectors have emerged as valuable tools for transgene delivery because of their ability to transduce nondividing cells and their capacity to sustain long-term transgene expression in target cells in vitro and in vivo. However, despite significant progress, the production and concentration of high-titer, high-quality LV vector stocks is still cumbersome and costly. Methods Here we present a simplified protocol for LV vector production on a laboratory scale using HYPERFlask vessels. HYPERFlask vessels are high-yield, high-performance flasks that utilize a multilayered gas permeable growth surface for efficient gas exchange, allowing convenient production of high-titer LV vectors. For subsequent concentration of LV vector stocks produced in this way, we describe a facile protocol involving Mustang Q anion exchange membrane chromatography. Results Our results show that unconcentrated LV vector stocks with titers in excess of 108 transduction units (TU) per ml were obtained using HYPERFlasks and that these titers were higher than those produced in parallel using regular 150-cm2 tissue culture dishes. We also show that up to 500 ml of an unconcentrated LV vector stock prepared using a HYPERFlask vessel could be concentrated using a single Mustang Q Acrodisc with a membrane volume of 0.18 ml. Up to 5.3 × 1010 TU were recovered from a single HYPERFlask vessel. Conclusion The protocol described here is easy to implement and should facilitate high-titer LV vector production for preclinical studies in animal models without the need for multiple tissue culture dishes and ultracentrifugation-based concentration protocols. PMID:19220915

Applying of the array transducers' technology for surface acoustic waves materials characterization in the transient regime

International Nuclear Information System (INIS)

Frenet, D.

2000-01-01

In this document we present a theoretical and experimental study which has been led to design a surface acoustic wave device for local characterisation (relatively to the wavelength) of isotropic or anisotropic materials. The device is based on a phased-array transducer of conical shape we have specifically designed for this purpose. It operates in the impulsive mode, in the frequency range of 1-5 MHz. In order to deduce mechanical properties of the material, it is possible to measure the surface wave characteristics (velocity, attenuation,...). Different methods for measuring the wave velocity have been developed taking advantage of from the phased-array technology. The originality of theses methods relies on the fact that the measures are performed without moving the transducer. Consequently, the device requires no additional mechanical system and it is quite compact. In addition, this shortens the characterisation process duration comparatively to the usually available methods (e. g. the V(z) technique). In the theoretical section of this study, a versatile model allowing to simulate in the time harmonic regime as well as in the transient regime, the transmitted field, the field reflected on isotropic or anisotropic planar samples and the output voltage for transducers of arbitrary shapes has been developed. The model has been applied to the phased-array conical transducer as well as to more classical transducers such as planar (rectangular) or focusing (spherically or cylindrically shaped) transducers. It predicts not only the geometrical contributions of the reflected field and signal but also the leaky contributions related to the surface acoustic waves. (author)

Mature Results of a Prospective Randomized Trial Comparing 5-Flourouracil with Leucovorin to 5-Flourouracil with Levamisole as Adjuvant Therapy of Stage II and III Colorectal Cancer- The Israel Cooperative Oncology Group (ICOG Study

Directory of Open Access Journals (Sweden)

Arie Figer, Aviram Nissan, Adi Shani, Riva Borovick, Mariana Stiener, Mario Baras, Herbert R. Freund, Aaron Sulkes, Alexander Stojadinovic, Tamar Peretz

2011-01-01

Full Text Available Objective: Survival benefit with adjuvant therapy was shown in patients with Stage III colorectal cancer (CRC. This study evaluates long-term (10-year outcome in patients with CRC randomly assigned to adjuvant 5-Fluorouracil/Leucovorin (5FU+LV or 5-FU/Levamisole (5FU+LEV.Methods: Between 1990 and 1995, 398 patients with curatively resected Stage II-III CRC were randomly assigned to adjuvant 5FU+LV or 5FU+LEV for 12 months.Results: No difference was evident in 10-year relapse-free or overall survival between study groups. Grade III toxicity was similar between groups; however, neurotoxicity was significantly greater with 5FU+LEV (p=0.02 and gastrointestinal toxicity with 5FU+LV (p=0.03. Female patients treated with 5FU+LEV had improved overall survival.Conclusions: Adjuvant treatment of CRC is still based on leucovorin modulated fluorouracil. The long-term follow-up results of this trial indicate that the adjuvant treatment of Stage II-III CRC with 5FU+LV or 5FU+LEV is equally effective. The finding of improved survival in female subjects treated with 5FU+LEV warrants further study to determine if Levamisole is a better modulator of 5-FU than Leucovorin in this patient subset.

Pre-operative combined 5-FU, low dose leucovorin, and sequential radiation therapy for unresectable rectal cancer

International Nuclear Information System (INIS)

Minsky, B.D.; Cohen, A.M.; Kemeny, N.; Enker, W.E.; Kelsen, D.P.; Schwartz, G.; Saltz, L.; Dougherty, J.; Frankel, J.; Wiseberg, J.

1993-01-01

The authors performed a Phase 1 trial to determine the maximum tolerated dose of combined pre-operative radiation (5040 cGy) and 2 cycles (bolus daily x 5) of 5-FU and low dose LV (20 mg/m2), followed by surgery and 10 cycles of post-operative LV/5-FU in patients with unresectable primary or recurrent rectal cancer. Twelve patients were entered. The initial dose of 5-FU was 325 mg/m2. 5-FU was to be escalated while the LV remained constant at 20 mg/m2. Chemotherapy began on day 1 and radiation on day 8. The post-operative chemotherapy was not dose escalated; 5-FU: 425 mg/m2 and LV: 20 mg/m2. The median follow-up was 14 months (7--16 months). Following pre-operative therapy, the resectability rate with negative margins was 91% and the pathologic complete response rate was 9%. For the combined modality segment (preoperative) the incidence of any grade 3+ toxicity was diarrhea: 17%, dysuria: 8%, mucositis: 8%, and erythema: 8%. The median nadir counts were WBC: 3.1, HGB: 8.8, and PLT: 153000. The maximum tolerated dose of 5-FU for pre-operative combined LV/5-FU/RT was 325 mg/m2 with no escalation possible. Therefore, the recommended dose was less than 325 mg/m2. Since adequate doses of 5-FU to treat systemic disease could not be delivered until at least 3 months (cycle 3) following the start of therapy, the authors do not recommend that this 5-FU, low dose LV, and sequential radiation therapy regimen be used as presently designed. However, given the 91% resectability rate they remain encouraged with this approach. 31 refs., 1 fig., 2 tabs

Simulation of 3-D radiation beam patterns propagated through a planar interface from ultrasonic phased array transducers.

Science.gov (United States)

Song, Sung-Jin; Kim, Chang-Hwan

2002-05-01

Phased array transducers are quite often mounted on solid wedges with specific angles in many practical ultrasonic inspections of thin plates phased array techniques with testing set-up, it is essential to have thorough understanding on the characteristics of radiation beam pattern produced in the interrogated medium. To address such a need, this paper proposes a systematic way to calculate full 3-D radiation beam patterns produced in the interrogated solid medium by phased array transducers mounted on a solid wedge. In order to investigate the characteristics of radiation beam patterns in steel, simulation is carried out for 7.5 MHz array transducers mounted on an acrylic wedge with the angle of 15.45 degrees with various of steering angles and/or focal planes.

Design and performance of the drag-disc turbine transducer

International Nuclear Information System (INIS)

Averill, R.H.; Goodrich, L.D.; Ford, R.E.

1979-01-01

Mass flow rates at the Loss-of-Fluid Test (LOFT) facility, EG and G Idaho, Inc., at the Idaho National Engineering Laboratory, are measured with the drag-disc turbine transducer (DTT). Operational description of the DTT and the developmental effort are discussed. Performance data and experiences with this transducer have been evaluated and are presented in this paper

Surface glycosaminoglycans mediate adherence between HeLa cells and Lactobacillus salivarius Lv72.

Science.gov (United States)

Martín, Rebeca; Martín, Carla; Escobedo, Susana; Suárez, Juan E; Quirós, Luis M

2013-09-17

The adhesion of lactobacilli to the vaginal surface is of paramount importance to develop their probiotic functions. For this reason, the role of HeLa cell surface proteoglycans in the attachment of Lactobacillus salivarius Lv72, a mutualistic strain of vaginal origin, was investigated. Incubation of cultures with a variety of glycosaminoglycans (chondroitin sulfate A and C, heparin and heparan sulfate) resulted in marked binding interference. However, no single glycosaminoglycan was able to completely abolish cell binding, the sum of all having an additive effect that suggests cooperation between them and recognition of specific adhesins on the bacterial surface. In contrast, chondroitin sulfate B enhanced cell to cell attachment, showing the relevance of the stereochemistry of the uronic acid and the sulfation pattern on binding. Elimination of the HeLa surface glycosaminoglycans with lyases also resulted in severe adherence impairment. Advantage was taken of the Lactobacillus-glycosaminoglycans interaction to identify an adhesin from the bacterial surface. This protein, identify as a soluble binding protein of an ABC transporter system (OppA) by MALDI-TOF/(MS), was overproduced in Escherichia coli, purified and shown to interfere with L. salivarius Lv72 adhesion to HeLa cells. These data suggest that glycosaminoglycans play a fundamental role in attachment of mutualistic bacteria to the epithelium that lines the cavities where the normal microbiota thrives, OppA being a bacterial adhesin involved in the process.

Updated Results of Ultrasonic Transducer Irradiation Test

Energy Technology Data Exchange (ETDEWEB)

Daw, Joshua; Palmer, Joe [Idaho National Laboratory, P.O. Box 1625, MS 4112, Idaho Falls, ID, 38415-3840 (United States); Ramuhalli, Pradeep; Keller, Paul; Montgomery, Robert [Pacific Northwest National Laboratory, 902 Battelle Blvd. Richland, WA, 99354 (United States); Chien, Hual-Te [Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL, 60439 (United States); Tittmann, Bernhard; Reinhardt, Brian [Pennsylvania State University, 212 Earth and Engr. Sciences Building, University Park, PA, 16802 (United States); Kohse, Gordon [Massachusetts Institute of Technology, 77 Massachusetts Ave. Cambridge, MA 02139 (United States); Rempe, Joy [Rempe and Associates, LLC, 360 Stillwater, Idaho Falls, ID 83404 (United States); Villard, J.F. [Commissariat a l' energie atomique et aux energies alternatives, Centre d' etudes de Cadarache, 13108 Saint-Paul-lez-Durance (France)

2015-07-01

Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 10{sup 21} n/cm{sup 2}. A multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET-ASI) program also provided initial support for this effort. This irradiation, which started in February 2014, is an instrumented lead test and real-time transducer performance data are collected along with temperature and neutron and gamma flux data. The irradiation is ongoing and will continue to approximately mid-2015. To date, very encouraging results have been attained as several transducers continue to operate under irradiation. (authors)

The role of signal transducer and activator of transcription 5 in the inhibitory effects of GH on adipocyte differentiation

DEFF Research Database (Denmark)

Richter, H E; Albrektsen, T; Billestrup, Nils

2003-01-01

GH inhibits primary rat preadipocyte differentiation and expression of late genes required for terminal differentiation. Here we show that GH-mediated inhibition of fatty acid-binding protein aP2 gene expression correlates with the activation of the Janus kinase-2/signal transducer and activator ...

Broadband and High Sensitive Time-of-Flight Diffraction Ultrasonic Transducers Based on PMNT/Epoxy 1–3 Piezoelectric Composite

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Dongxu Liu

2015-03-01

Full Text Available 5–6 MHz PMNT/epoxy 1–3 composites were prepared by a modified dice-and-fill method. They exhibit excellent properties for ultrasonic transducer applications, such as ultrahigh thickness electromechanical coupling coefficient kt (85.7%, large piezoelectric coefficient d33 (1209 pC/N, and relatively low acoustic impedance Z (1.82 × 107 kg/(m2·s. Besides, two types of Time-of-Flight Diffraction (TOFD ultrasonic transducers have been designed, fabricated, and characterized, which have different matching layer schemes with the acoustic impedance of 4.8 and 5.7 × 106 kg/(m2·s, respectively. In the detection on a backwall of 12.7 mm polystyrene, the former exhibits higher detectivity, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −21.93 dB and 102.7%, respectively, while the later exhibits broader bandwidth, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −24.08 dB and 117.3%, respectively. These TOFD ultrasonic transducers based on PMNT/epoxy 1–3 composite exhibit considerably improved performance over the commercial PZT/epoxy 1–3 composite TOFD ultrasonic transducer.

Class H power amplifier for power saving in fluxgate current transducers

OpenAIRE

Velasco Quesada, Guillermo; Román Lumbreras, Manuel; Pérez Delgado, Raul; Conesa Roca, Alfons

2016-01-01

This paper presents a new improvement in the design of a fluxgate-based current transducer in order to reduce the power consumption of control electronics. The proposed improvement involves the replacement of the output linear amplifier of the transducer by a class H amplifier. The output amplifier is devoted to the magnetic flux compensation and generates the transducer output current, which is proportional to the current to be measured. In this way, it is possible to reduce significantly th...

Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

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Z. Hashemiyan

2015-01-01

Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

Lamb wave tuning curve calibration for surface-bonded piezoelectric transducers

International Nuclear Information System (INIS)

Sohn, Hoon; Lee, Sang Jun

2010-01-01

Surface-bonded lead zirconate titanate (PZT) transducers have been widely used for guided wave generation and measurement. For selective actuation and sensing of Lamb wave modes, the sizes of the transducers and the driving frequency of the input waveform should be tuned. For this purpose, a theoretical Lamb wave tuning curve (LWTC) of a specific transducer size is generally obtained. Here, the LWTC plots each Lamb wave mode' amplitude as a function of the driving frequency. However, a discrepancy between experimental and existing theoretical LWTCs has been observed due to little consideration of the bonding layer and the energy distribution between Lamb wave modes. In this study, calibration techniques for theoretical LWTCs are proposed. First, a theoretical LWTC is developed when circular PZT transducers are used for both Lamb wave excitation and sensing. Then, the LWTC is calibrated by estimating the effective PZT size with PZT admittance measurement. Finally, the energy distributions among symmetric and antisymmetric modes are taken into account for better prediction of the relative amplitudes between Lamb wave modes. The effectiveness of the proposed calibration techniques is examined through numerical simulations and experimental estimation of the LWTC using the circular PZT transducers instrumented on an aluminum plate

A piezoelectric transducer for measurement of dynamic strain in pipes

Energy Technology Data Exchange (ETDEWEB)

Lannes, Daniel P.; Gama, Antonio L. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Mecanica

2009-07-01

This work presents a new strain transducer developed mainly for the inspection and evaluation of piping systems with excessive vibration. Vibration is one of the most common causes of piping failures. These failures could be avoided if the vibration problems were identified and quickly evaluated. Procedures for evaluation of piping vibration are usually based on pipe velocity or displacement. Although simple and fast, these procedures do not provide precise information on the risk of piping fatigue failure. Through the measurement of pipe dynamic strains the risk of failure due to vibration can be determined more accurately. The measurement of strain is usually performed using the conventional strain gauge method. Although efficient and accurate, the implementation of the conventional strain gauge technique may become a difficult task in certain industrial scenarios. Motivated by the need of a simple and rapid method for pipe dynamic strain measurement, a piezoelectric dynamic strain transducer was developed. This work presents a description of the piezoelectric strain transducer and the preliminary results of pipe strain measurements. The transducer can be applied directly to the pipe through magnetic bases allowing for the quick measurement of the dynamic strains in many points of the pipe. The transducer signal can be read with the same commercial data collectors used for accelerometers. (author)

Fiber-optic coupled pressure transducer

International Nuclear Information System (INIS)

Tallman, C.R.; Wingate, F.P.; Ballard, E.O.

1979-01-01

A fiber-optic coupled pressure transducer was developed for measurement of pressure transients produced by fast electrical discharges in laser cavities. A detailed description of the design and performance will be given. Shock tube performance and measurements in direct electrical discharge regions will be presented

Calculations for Piezoelectric Ultrasonic Transducers

DEFF Research Database (Denmark)

Jensen, Henrik

1986-01-01

Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a boay which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation...

Double-modulation of 5-Fluorouracil by methotrexate and leucovorin in advanced colorectal-carcinoma.

Science.gov (United States)

Leone, B; Romero, A; Rabinovich, M; Vallejo, C; Bianco, A; Perez, J; Rodriguez, R; Cuevas, M; Machiavelli, M; Paris, A; Lacava, J

1993-11-01

A phase II trial was performed to evaluate the efficacy and toxicity of a double modulation of 5-fluorouracil (5-FU) by methotrexate (MTX) and leucovorin (LV) as first line chemotherapy in advanced colorectal carcinoma. Between January 1990, and April 1992, 42 patients with metastatic or advanced recurrent (inoperable) colorectal cancer were entered into the study. Therapy consisted of a sequential combination of MTX, LV and 5-FU. MTX was administered at a dose of 150 mg/m2 over 20 minutes I.V. infusion at hour (h) 0, followed 19 h later by LV 50 mg/m2 over 2 h infusion. 5-FU 900 mg/m2 was given by I.V. push injection at h 20. Starting 24 h after MTX administration all patients received LV 15 mg/m2 intramuscularly every 6 h for six doses. Treatment was repeated every 15 days until progressive disease, severe toxicity, or death. Four patients were considered not evaluable for response. Objective regression (OR) was observed in 14 of 38 patients (37%, 95% confidence interval 23-53%). Two patients (5%) obtained complete response (CR) and 12 (32%) partial response (PR). Median time to treatment failure was 6 months (range 1-21). Median survival for the whole group of patients was 13 months (range 1-27). Toxicity was within acceptable limits but one therapy-related death due to severe leukopenia and sepsis was observed. Double modulation of 5-FU with MTX and low dose of LV is an active regimen against advanced colorectal carcinoma and represents a promising strategy that should be further explored.

Development of an omni-directional shear horizontal mode magnetostrictive patch transducer

Science.gov (United States)

Liu, Zenghua; Hu, Yanan; Xie, Muwen; Fan, Junwei; He, Cunfu; Wu, Bin

2018-04-01

The fundamental shear horizontal wave, SH0 mode, has great potential in defect detection and on-line monitoring with large scale and high efficiency in plate-like structures because of its non-dispersive characteristics. Aiming at consistently exciting single SH0 mode in plate-like structures, an omni-directional shear horizontal mode magnetostrictive patch transducer (OSHM-MPT) is developed on the basis of magnetostrictive effect. It consists of four fan-shaped array elements and corresponding plane solenoid array (PSA) coils, four fan-shaped permanent magnets and a circular nickel patch. The experimental results verify that the developed transducer can effectively produce the single SH0 mode in an aluminum plate. The frequency response characteristics of this developed transducer are tested. The results demonstrate that the proposed OSHM-MPT has a center frequency of 300kHz related to the distance between adjacent arc-shaped steps of the PSA coils. Furthermore, omni-directivity of this developed transducer is tested. The results demonstrate that the developed transducer has a high omnidirectional consistency.

A capacitive ultrasonic transducer based on parametric resonance.

Science.gov (United States)

Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F

2017-07-24

A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of f o . When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2f o with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at f o frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

A computerized check-out system for transducers in nuclear power plants

International Nuclear Information System (INIS)

Brandt, A.

1984-01-01

A computerized system for the acquisition, administration and recording of test data of about 1000 pressure meters (transducers) being collected annually in nuclear power stations is described. The Mobile System is set up by three components - the control pressure device, the intelligent interface and the microcomputer (PDP 11/23, 256 kB) - the whole being assembled on a moveable wagon which allows on site measurement of the transducers. The PDP 11/23, fully integrated in a VT 103 video terminal, connects to the interface via an IEEE-488 bus system. Its keyboard is equipped with operation keys to handle and control the different test phases - uncoupling the transducer from plant operation, linking the transducer to the Mobile System, testing for leaks in the pipe system, recording and correcting the characteristic curve, reinstallation of the transducer in plant operation. Filling and emptying of the pipelines for high pressure measuring is computer controlled as well. As each Mobile System is a stand-alone test device, the number of systems is freely selectable according to environmental conditions (radiative and non-radiative zones, accessability etc.), failure resp. availability considerations and other boundary conditions. Data transport to and from the Stationary System is done via magnetic tape cartridges (256 KB), which may pick-up data of 150 transducers, or online via twisted pair cable connections between the measuring points and the Stationary System. (orig./GL) [de

Differentiated neuroprogenitor cells incubated with human or canine adenovirus, or lentiviral vectors have distinct transcriptome profiles.

Directory of Open Access Journals (Sweden)

Stefania Piersanti

Full Text Available Several studies have demonstrated the potential for vector-mediated gene transfer to the brain. Helper-dependent (HD human (HAd and canine (CAV-2 adenovirus, and VSV-G-pseudotyped self-inactivating HIV-1 vectors (LV effectively transduce human brain cells and their toxicity has been partly analysed. However, their effect on the brain homeostasis is far from fully defined, especially because of the complexity of the central nervous system (CNS. With the goal of dissecting the toxicogenomic signatures of the three vectors for human neurons, we transduced a bona fide human neuronal system with HD-HAd, HD-CAV-2 and LV. We analysed the transcriptional response of more than 47,000 transcripts using gene chips. Chip data showed that HD-CAV-2 and LV vectors activated the innate arm of the immune response, including Toll-like receptors and hyaluronan circuits. LV vector also induced an IFN response. Moreover, HD-CAV-2 and LV vectors affected DNA damage pathways--but in opposite directions--suggesting a differential response of the p53 and ATM pathways to the vector genomes. As a general response to the vectors, human neurons activated pro-survival genes and neuron morphogenesis, presumably with the goal of re-establishing homeostasis. These data are complementary to in vivo studies on brain vector toxicity and allow a better understanding of the impact of viral vectors on human neurons, and mechanistic approaches to improve the therapeutic impact of brain-directed gene transfer.

Lead-free piezoelectric materials and ultrasonic transducers for medical imaging

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Elaheh Taghaddos

2015-06-01

Full Text Available Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging. In this paper, firstly, the most promising lead-free compositions with perovskite structure for medical imaging applications have been reviewed. The electromechanical properties of various lead-free ceramics, composites, and single crystals based on barium titanate, bismuth sodium titanate, potassium sodium niobate, and lithium niobate are presented. Then, fundamental principles and design considerations of ultrasonic transducers are briefly described. Finally, recent developments in lead-free ultrasonic probes are discussed and their acoustic performance is compared to lead-based transducers. Focused transducers with different beam focusing methods such as lens focusing and mechanical shaping are explained. Additionally, acoustic characteristics of lead-free probes including the pulse-echo results as well as their imaging capabilities for various applications such as phantom imaging, in vitro intravascular ultrasound imaging of swine aorta, and in vivo or ex vivo imaging of human eyes and skin are reviewed.

A Novel Rotary Piezoelectric Motor Using First Bending Hybrid Transducers

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Yingxiang Liu

2015-08-01

Full Text Available We report a novel rotary piezoelectric motor using bending transducers in this work. Three transducers are used to drive a disk-shaped rotor together by the elliptical movements of their driving tips; these motions are produced by the hybrid of two first bending vibration modes. The proposed piezoelectric transducer has a simple structure as it only contains an aluminum alloy beam and four pieces of PZT plates. Symmetrical structure is the only necessary condition in the design process as it will ensure the resonance frequencies of the two orthogonal first bending modes are equal. Transducers with first bending resonance frequency of about 53 kHz were fabricated and assembled into a rotary motor. The proposed motor exhibits good performance on speed and torque control. Under a working frequency of 53.2 kHz, the maximum no-load speed and the maximum torque of the prototype are tested to be 53.3 rpm and of 27 mN·m.

Cytotoxicity and inhibitory effects of low-concentration triclosan on adipogenic differentiation of human mesenchymal stem cells

Energy Technology Data Exchange (ETDEWEB)

Guo, Li-Wu [Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Wu, Qiangen [Division of Biochemical Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Green, Bridgett; Nolen, Greg [Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Shi, Leming [Division of Systems Biology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); LoSurdo, Jessica [Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 (United States); Deng, Helen [Arkansas Department of Health, Little Rock, AR 72205 (United States); Bauer, Steven [Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892 (United States); Fang, Jia-Long, E-mail: jia-long.fang@fda.hhs.gov [Division of Biochemical Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States); Ning, Baitang, E-mail: baitang.ning@fda.hhs.gov [Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States)

2012-07-15

Humans at all ages are continually exposed to triclosan (TCS), a widely used antimicrobial agent that can be found in many daily hygiene products, such as toothpastes and shampoos; however, the toxicological and biological effects of TCS in the human body after long-term and low-concentration exposure are far from being well understood. In the current study, we investigated the effects of TCS on the differentiation of human mesenchymal stem cells (hMSCs) by measuring the cytotoxicity, morphological changes, lipid accumulation, and the expression of adipocyte differentiation biomarkers during 21-day adipogenesis. Significant cytotoxicity was observed in un-induced hMSCs treated with high-concentration TCS (≥ 5.0 μM TCS), but not with low-concentration treatments (≤ 2.5 μM TCS). TCS inhibited adipocyte differentiation of hMSCs in a concentration-dependent manner in the 0.156 to 2.5 μM range as indicated by morphological changes with Oil Red O staining, which is an index of lipid accumulation. The inhibitory effect was confirmed by a decrease in gene expression of specific adipocyte differentiation biomarkers including adipocyte protein 2, lipoprotein lipase, and adiponectin. Our study demonstrates that TCS inhibits adipocyte differentiation of hMSCs under concentrations that are not cytotoxic and in the range observed in human blood. -- Highlights: ► TCS is cytotoxic to un-induced hMSCs at concentrations ≥ 5.0 μM. ► TCS at concentrations ≤ 2.5 μM is not cytotoxic to induced hMSCs. ► TCS at non-cytotoxic concentrations inhibits lipid formation in induced hMSCs. ► TCS decreases the expression of specific biomarkers of adipocyte differentiation. ► TCS at concentrations observed in human blood inhibits adipogenesis of hMSCs.

Cytotoxicity and inhibitory effects of low-concentration triclosan on adipogenic differentiation of human mesenchymal stem cells

International Nuclear Information System (INIS)

Guo, Li-Wu; Wu, Qiangen; Green, Bridgett; Nolen, Greg; Shi, Leming; LoSurdo, Jessica; Deng, Helen; Bauer, Steven; Fang, Jia-Long; Ning, Baitang

2012-01-01

Humans at all ages are continually exposed to triclosan (TCS), a widely used antimicrobial agent that can be found in many daily hygiene products, such as toothpastes and shampoos; however, the toxicological and biological effects of TCS in the human body after long-term and low-concentration exposure are far from being well understood. In the current study, we investigated the effects of TCS on the differentiation of human mesenchymal stem cells (hMSCs) by measuring the cytotoxicity, morphological changes, lipid accumulation, and the expression of adipocyte differentiation biomarkers during 21-day adipogenesis. Significant cytotoxicity was observed in un-induced hMSCs treated with high-concentration TCS (≥ 5.0 μM TCS), but not with low-concentration treatments (≤ 2.5 μM TCS). TCS inhibited adipocyte differentiation of hMSCs in a concentration-dependent manner in the 0.156 to 2.5 μM range as indicated by morphological changes with Oil Red O staining, which is an index of lipid accumulation. The inhibitory effect was confirmed by a decrease in gene expression of specific adipocyte differentiation biomarkers including adipocyte protein 2, lipoprotein lipase, and adiponectin. Our study demonstrates that TCS inhibits adipocyte differentiation of hMSCs under concentrations that are not cytotoxic and in the range observed in human blood. -- Highlights: ► TCS is cytotoxic to un-induced hMSCs at concentrations ≥ 5.0 μM. ► TCS at concentrations ≤ 2.5 μM is not cytotoxic to induced hMSCs. ► TCS at non-cytotoxic concentrations inhibits lipid formation in induced hMSCs. ► TCS decreases the expression of specific biomarkers of adipocyte differentiation. ► TCS at concentrations observed in human blood inhibits adipogenesis of hMSCs.

A New High-Temperature Ultrasonic Transducer for Continuous Inspection.

Science.gov (United States)

Amini, Mohammad Hossein; Sinclair, Anthony N; Coyle, Thomas W

2016-03-01

A novel design of piezoelectric ultrasonic transducer is introduced, suitable for operation at temperatures of up to 700 °C-800 °C. Lithium niobate single crystal is chosen as the piezoelectric element primarily due to the high Curie temperature of 1200 °C. A backing element based on a porous ceramic is designed for which the pore volume fraction and average pore diameter in the ceramic matrix can be controlled in the manufacturing process; this enables the acoustic impedance and attenuation to be selected to match their optimal values as predicted by a one-dimensional transducer model of the entire transducer. Porous zirconia is selected as the ceramic matrix material of the backing element to obtain an ultrasonic signal with center frequency of 2.7-3 MHz, and 3-dB bandwidth of 90%-95% at the targeted operating temperature. Acoustic coupling of the piezocrystal to the backing element and matching layer is investigated using commercially available high-temperature adhesives and brazing alloys. The performance of the transducer as a function of temperature is studied. Stable bonding and clear signals were obtained using an aluminum brazing alloy as the bonding agent.

High Precision UTDR Measurements by Sonic Velocity Compensation with Reference Transducer

Directory of Open Access Journals (Sweden)

Sam Stade

2014-07-01

Full Text Available An ultrasonic sensor design with sonic velocity compensation is developed to improve the accuracy of distance measurement in membrane modules. High accuracy real-time distance measurements are needed in membrane fouling and compaction studies. The benefits of the sonic velocity compensation with a reference transducer are compared to the sonic velocity calculated with the measured temperature and pressure using the model by Belogol’skii, Sekoyan et al. In the experiments the temperature was changed from 25 to 60 °C at pressures of 0.1, 0.3 and 0.5 MPa. The set measurement distance was 17.8 mm. Distance measurements with sonic velocity compensation were over ten times more accurate than the ones calculated based on the model. Using the reference transducer measured sonic velocity, the standard deviations for the distance measurements varied from 0.6 to 2.0 µm, while using the calculated sonic velocity the standard deviations were 21–39 µm. In industrial liquors, not only the temperature and the pressure, which were studied in this paper, but also the properties of the filtered solution, such as solute concentration, density, viscosity, etc., may vary greatly, leading to inaccuracy in the use of the Belogol’skii, Sekoyan et al. model. Therefore, calibration of the sonic velocity with reference transducers is needed for accurate distance measurements.

A spiral wave front beacon for underwater navigation: transducer prototypes and testing.

Science.gov (United States)

Dzikowicz, Benjamin R; Hefner, Brian T

2012-05-01

Transducers for acoustic beacons which can produce outgoing signals with wave fronts whose horizontal cross sections are circular or spiral are studied experimentally. A remote hydrophone is used to determine its aspect relative to the transducers by comparing the phase of the circular signal to the phase of the spiral signal. The transducers for a "physical-spiral" beacon are made by forming a strip of 1-3 piezocomposite transducer material around either a circular or spiral backing. A "phased-spiral" beacon is made from an array of transducer elements which can be driven either in phase or staggered out of phase so as to produce signals with either a circular or spiral wave front. Measurements are made to study outgoing signals and their usefulness in determining aspect angle. Vertical beam width is also examined and phase corrections applied when the hydrophone is out of the horizontal plane of the beacon. While numerical simulations indicate that the discontinuity in the physical-spiral beacon introduces errors into the measured phase, damping observed at the ends of the piezocomposite material is a more significant source of error. This damping is also reflected in laser Doppler vibrometer measurements of the transducer's surface velocity.

Ultrasonic Transducer Design for the Axial Flaw Detection of Dissimilar Metal Weld

International Nuclear Information System (INIS)

Yoon, Byung Sik; Kim, Yong Sik; Yang, Seung Han

2011-01-01

Dissimilar metal welds in nuclear power plant are known as very susceptible to PWSCC flaws, and periodically inspected by the qualified inspector and qualified procedure during in-service inspection period. According to field survey data, the majority of their DMWs are located on tapered nozzle or adjacent to a tapered component. These types of configurations restrict examination access and also limit examination volume coverage. Additionally, circumferential scan for axially oriented flaw is very difficult to detect located on tapered surface because the transducer can't receive flaw response from reflector for miss-orientation. To overcome this miss-orientation, it is necessary adapt skewed ultrasonic transducer accommodate tapered surface. The skewed refracted longitudinal ultrasonic transducer designed by modeling and manufactured from the modelling result for axial flaw detection. Experimental results showed that the skewed refracted longitudinal ultrasonic transducer get higher flaw response than non-skewed refracted longitudinal ultrasonic transducer

Ultrasonic field analysis program for transducer design in the nuclear industry

International Nuclear Information System (INIS)

Singh, G.P.; Rose, J.L.

1980-02-01

An ultrasonic field analysis program is presented that can be used for transducer design in the nuclear industry. Calculation routines that make use of Huygen's principle in a field analysis model are introduced that enable such field characteristics as axial and lateral resolution, beam symmetry, and gain variation throughout the ultrasonic field to be optimized. Mathematical details are presented along with several sample problems that show comparisons with classical results reported in the literature and with experimental data. Several sample problems that are of interest to the nuclear industry are also included, along with some that satisfy both academical and practical curiosity. These include transducer shape effects, pulse shape effects, crystal vibration variation, and an introduction to such novel transducer designs as annular arrays and dual element angle beam transducers

A Float Type Liquid Level Measuring System Using a Modified Inductive Transducer

Directory of Open Access Journals (Sweden)

Samik MARICK

2014-11-01

Full Text Available Float type liquid level sensor is generally used as a very simple technique for local level indication and level switching. In the present paper a technique has been proposed to transmit the measured liquid level signal of a float type sensor at remote terminal using a modified differential inductance type electromechanical transducer. The theoretical characteristic equation of this transducer has been derived. A prototype unit of the transducer has been developed and fabricated and its performance characteristic has been experimentally determined. The experimental results are reported in the paper. From experimental data, a very good linear characteristic of the proposed level transducer has been observed.

Torque magnetometry by use of capacitance type transducer

International Nuclear Information System (INIS)

Braught, M.C.; Pechan, M.J.

1992-01-01

Interfacial anisotropy in magnetic multilayered samples comprised of nanometer thick magnetic layers alternating with non-magnetic layers is investigated by torque magnetometry in the temperature regime of 4 to 300K. The design, construction and use of a capacitance type transducer wherein the sample is mounted directly on with the plate of the capacitor, will be described. As a result the sample and transducer spatially coexist at the sample temperature in an applied external field, eliminating mechanical coupling from the cryogenic region to a remote room temperature transducer. The capacitor measuring the torque of the sample is paired with a reference capacitor. The difference between torque influenced capacitance and the reference is then determined by a differential transimpedance amplifier. Since both capacitors are physically identical variables such as temperature, vibration, orientation and external devices are minimized. Torques up to 300 dyne-cm can be measured with a sensitivity of 0.010 dyne-cm

A novel serrated columnar phased array ultrasonic transducer

Science.gov (United States)

Zou, Cheng; Sun, Zhenguo; Cai, Dong; Song, Hongwei; Chen, Qiang

2016-02-01

Traditionally, wedges are required to generate transverse waves in a solid specimen and mechanical rotation device is needed for interrogation of a specimen with a hollow bore, such as high speed railway locomotive axles, turbine rotors, etc. In order to eliminate the mechanical rotation process, a novel array pattern of phased array ultrasonic transducers named as serrated columnar phased array ultrasonic transducer (SCPAUT) is designed. The elementary transducers are planar rectangular, located on the outside surface of a cylinder. This layout is aimed to generate electrically rotating transverse waveforms so as to inspect the longitudinal cracks on the outside surface of a specimen which has a hollow bore at the center, such as the high speed railway locomotive axles. The general geometry of the SCPAUT and the inspection system are illustrated. A FEM model and mockup experiment has been carried out. The experiment results are in good agreement with the FEM simulation results.

Six-Axis Force-Torque Transducer for Mars 2018 Mission, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — A transducer element that is hearty enough for a Mars lander mission needs to be developed so that a six-axis force and torque transducer is possible. The technical...

Numerical Transducer Modeling

DEFF Research Database (Denmark)

Henriquez, Vicente Cutanda

This thesis describes the development of a numerical model of the propagation of sound waves in fluids with viscous and thermal losses, with application to the simulation of acoustic transducers, in particular condenser microphones for measurement. The theoretical basis is presented, numerical...... manipulations are developed to satisfy the more complicated boundary conditions, and a model of a condenser microphone with a coupled membrane is developed. The model is tested against measurements of ¼ inch condenser microphones and analytical calculations. A detailed discussion of the results is given....

An all-optical fiber optic photoacoustic transducer

Science.gov (United States)

Thathachary, Supriya V.; Motameni, Cameron; Ashkenazi, Shai

2018-02-01

A highly sensitive fiber-optic Fabry-Perot photoacoustic transducer is proposed in this work. The transducer will consist of separate transmit and receive fibers. The receiver will be composed of a Fabry-Perot Ultrasound sensor with a selfwritten waveguide with all-optical ultrasound detection with high sensitivity. In previous work, we have shown an increase in resonator Q-factor from 1900 to 3200 for a simulated Fabry-Perot ultrasound detector of 45 μm thickness upon including a waveguide to limit lateral power losses. Subsequently, we demonstrated a prototype device with 30nm gold mirrors and a cavity composed of the photosensitive polymer Benzocyclobutene. This 80 µm thick device showed an improvement in its Q-factor from 2500 to 5200 after a selfaligned waveguide was written into the cavity using UV exposure. Current work uses a significantly faster fabrication technique using a combination of UV-cured epoxies for the cavity medium, and the waveguide within it. This reduces the fabrication time from several hours to a few minutes, and significantly lowers the cost of fabrication. We use a dip-coating technique to deposit the polymer layer. Future work will include the use of Dielectric Bragg mirrors in place of gold to achieve better reflectivity, thereby further improving the Q-factor of the device. The complete transducer presents an ideal solution for intravascular imaging in cases where tissue differentiation is desirable, an important feature in interventional procedures where arterial perforation is a risk. The final design proposed comprises the transducer within a guidewire to guide interventions for Chronic Total Occlusions, a disease state for which there are currently no invasive imaging options.

Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

Energy Technology Data Exchange (ETDEWEB)

Hu, M.; Bai, Y. Z., E-mail: abai@mail.hust.edu.cn; Zhou, Z. B., E-mail: zhouzb@mail.hust.edu.cn; Li, Z. X.; Luo, J. [MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

2014-05-15

The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided.

Resonant frequency detection and adjustment method for a capacitive transducer with differential transformer bridge

International Nuclear Information System (INIS)

Hu, M.; Bai, Y. Z.; Zhou, Z. B.; Li, Z. X.; Luo, J.

2014-01-01

The capacitive transducer with differential transformer bridge is widely used in ultra-sensitive space accelerometers due to their simple structure and high resolution. In this paper, the front-end electronics of an inductive-capacitive resonant bridge transducer is analyzed. The analysis result shows that the performance of this transducer depends upon the case that the AC pumping frequency operates at the resonance point of the inductive-capacitive bridge. The effect of possible mismatch between the AC pumping frequency and the actual resonant frequency is discussed, and the theoretical analysis indicates that the output voltage noise of the front-end electronics will deteriorate by a factor of about 3 due to either a 5% variation of the AC pumping frequency or a 10% variation of the tuning capacitance. A pre-scanning method to determine the actual resonant frequency is proposed followed by the adjustment of the operating frequency or the change of the tuning capacitance in order to maintain expected high resolution level. An experiment to verify the mismatching effect and the adjustment method is provided

Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

Science.gov (United States)

Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

2013-01-01

An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

Ferroelectret non-contact ultrasonic transducers

Czech Academy of Sciences Publication Activity Database

Bovtun, Viktor; Döring, J.; Bartusch, J.; Beck, U.; Erhard, A.; Yakymenko, Y.

2007-01-01

Roč. 88, č. 4 (2007), s. 737-743 ISSN 0947-8396 R&D Projects: GA ČR(CZ) GA202/06/0403 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectrets * polymers * ultrasonic transducers Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.857, year: 2007

A ring transducer system for medical ultrasound research.

Science.gov (United States)

Waag, Robert C; Fedewa, Russell J

2006-10-01

An ultrasonic ring transducer system has been developed for experimental studies of scattering and imaging. The transducer consists of 2048 rectangular elements with a 2.5-MHz center frequency, a 67% -6 dB bandwidth, and a 0.23-mm pitch arranged in a 150-mm-diameter ring with a 25-mm elevation. At the center frequency, the element size is 0.30lambda x 42lambda and the pitch is 0.38lambda. The system has 128 parallel transmit channels, 16 parallel receive channels, a 2048:128 transmit multiplexer, a 2048:16 receive multiplexer, independently programmable transmit waveforms with 8-bit resolution, and receive amplifiers with time variable gain independently programmable over a 40-dB range. Receive signals are sampled at 20 MHz with 12-bit resolution. Arbitrary transmit and receive apertures can be synthesized. Calibration software minimizes system nonidealities caused by noncircularity of the ring and element-to-element response differences. Application software enables the system to be used by specification of high-level parameters in control files from which low-level hardware-dependent parameters are derived by specialized code. Use of the system is illustrated by producing focused and steered beams, synthesizing a spatially limited plane wave, measuring angular scattering, and forming b-scan images.

Ultrasonic transducer design for uniform insonation

International Nuclear Information System (INIS)

Harrison, G.H.; Balcer-Kubiczek, E.K.; McCulloch, D.

1984-01-01

Techniques used in transducer development for acoustical imaging have been evaluated for the purpose of producing broad, uniform ultrasonic fields from planar radiators. Such fields should be useful in hyperthermia, physical therapy, and ultrasonic bioeffects studies. Fourier inversion of the circ function yielded a source velocity distribution proportional to (P/r) exp ((-ik/2Z) (2Z/sup 2/+r/sup 2/)) J/sub 1/(krP/Z), where r is the radial source coordinate, k is the wave number, and P is the desired radius of uniform insonation at a depth Z in water. This source distribution can be truncated without significantly degrading the solution. A simpler solution consists of exponentially shading the edge of an otherwise uniformly excited disk transducer. This approach was successfully approximated experimentally

Effect of the Matching Circuit on the Electromechanical Characteristics of Sandwiched Piezoelectric Transducers

Directory of Open Access Journals (Sweden)

Shuyu Lin

2017-02-01

Full Text Available The input electrical impedance behaves as a capacitive when a piezoelectric transducer is excited near its resonance frequency. In order to increase the energy transmission efficiency, a series or parallel inductor should be used to compensate the capacitive impedance of the piezoelectric transducer. In this paper, the effect of the series matching inductor on the electromechanical characteristics of the piezoelectric transducer is analyzed. The dependency of the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient, the electrical quality factor and the electro-acoustical efficiency on the matching inductor is obtained. It is shown that apart from compensating the capacitive impedance of the piezoelectric transducer, the series matching inductor can also change the electromechanical characteristics of the piezoelectric transducer. When series matching inductor is increased, the resonance frequency is decreased and the anti-resonance unchanged; the effective electromechanical coupling coefficient is increased. For the electrical quality factor and the electroacoustic efficiency, the dependency on the matching inductor is different when the transducer is operated at the resonance and the anti-resonance frequency. The electromechanical characteristics of the piezoelectric transducer with series matching inductor are measured. It is shown that the theoretically predicted relationship between the electromechanical characteristics and the series matching inductor is in good agreement with the experimental results.

Effect of the Matching Circuit on the Electromechanical Characteristics of Sandwiched Piezoelectric Transducers.

Science.gov (United States)

Lin, Shuyu; Xu, Jie

2017-02-10

The input electrical impedance behaves as a capacitive when a piezoelectric transducer is excited near its resonance frequency. In order to increase the energy transmission efficiency, a series or parallel inductor should be used to compensate the capacitive impedance of the piezoelectric transducer. In this paper, the effect of the series matching inductor on the electromechanical characteristics of the piezoelectric transducer is analyzed. The dependency of the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient, the electrical quality factor and the electro-acoustical efficiency on the matching inductor is obtained. It is shown that apart from compensating the capacitive impedance of the piezoelectric transducer, the series matching inductor can also change the electromechanical characteristics of the piezoelectric transducer. When series matching inductor is increased, the resonance frequency is decreased and the anti-resonance unchanged; the effective electromechanical coupling coefficient is increased. For the electrical quality factor and the electroacoustic efficiency, the dependency on the matching inductor is different when the transducer is operated at the resonance and the anti-resonance frequency. The electromechanical characteristics of the piezoelectric transducer with series matching inductor are measured. It is shown that the theoretically predicted relationship between the electromechanical characteristics and the series matching inductor is in good agreement with the experimental results.

Development of ultrasonic testing technique with the large transducer to inspect the containment vessel plates of nuclear power plant embedded in concrete

International Nuclear Information System (INIS)

Ishida, Hitoshi; Kurozumi, Yasuo; Kaneshima, Yoshiari

2004-01-01

The containment vessel plates embedded in concrete on Pressurized Water Reactors are inaccessible to inspect directly. Therefore, it is advisable to prepare inspection technology to detect existence and a location of corrosion on the embedded plates indirectly. In order to establish ultrasonic testing technique to be able to inspect the containment vessel plates embedded in concrete widely at the accessible point, experiments to detect artificial hollows simulating corrosion on a surface of a carbon steel plate mock-up covered with concrete simulating the embedded containment vessel plates were carried out with newly made ultrasonic transducers. We made newly low frequency (0.3 MHz and 0.5 MHz) surface shear horizontal (SH) wave transducers combined with three large active elements, which were equivalent to a 120mm width element. As a result of the experiments, the surface SH transducers could detect clearly the echo from the hollows with a depth of 9.5 mm and 19 mm at a distance of 1500mm from the transducers on the surface of the mock-up covered with concrete. Therefore, we evaluate that it is possible to detect the defects such as corrosion on the plates embedded in concrete with the newly made low frequency surface SH transducers with large elements. (author)

Test and evaluation of radioactively contaminated transducers and transmitters

International Nuclear Information System (INIS)

Strahm, R.C.

1983-01-01

People in the nuclear industries face some unique problems when handling, testing, or examining transducers and transmitters that have been radioactively contaminated. Although many people and organizations, including EG and G Idaho, have performed such work for many years, there are no set, structured approaches or procedures. This paper discusses a disciplined laboratory approach to contaminated transducer testing and evaluation, utilizing equipment and facilities developed specifically for this type of work

Variable mounting assembly for transducers employed in nuclear reactor vessel inspection apparatus

International Nuclear Information System (INIS)

Elsner, H.J.; Antol, R.F.; Castner, R.P.

1979-01-01

A positionally variable mounting assembly for transducers used to interrogate a nuclear reactor vessel is disclosed. Means are provided for clamping each transducer of an array about its flange in a central restraining block. The central restraining block is, in turn, pivotally mounted in a yoke. The yoke is movable secured to bars or rails bolted to the transducer plate and, by loosening appropriate bolts, can be moved along the ways or pivoted about one of them. Further, the restraining block can be removed from the yoke and pivotally clamped in a different orientation to upstanding brackets attached to the transducer array plate, or rotated through 90 0 and then secured again in the yoke

Note: Decoupling design for high frequency piezoelectric ultrasonic transducers with their clamping connections

Energy Technology Data Exchange (ETDEWEB)

Wang, F. J., E-mail: wangfujun@tju.edu.cn; Liang, C. M.; Tian, Y. L.; Zhao, X. Y.; Zhang, D. W. [Tianjin Key Laboratory of Equipment Design and Manufacturing Technology, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Zhang, H. J. [Tianjin Key Laboratory of Modern Mechatronics Equipment Technology, School of Mechanical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

2015-12-15

This work presents the flexure-mechanism based decoupling design between high frequency piezoelectric ultrasonic transducers and their clamping connections to improve ultrasonic energy transmission efficiency. The ring, prismatic beam, and circular notched hinge based flanges were presented, and the crucial geometric dimensions of the transducers with the flexure decoupling flanges were determined. Finite element analysis (FEA) was carried out to investigate the dynamic characteristics of the transducers. Finally, experiments were conducted to examine and verify the effects of the proposed decoupling flanges. FEA and experimental results show that smaller frequency deviations and larger tip displacement amplitudes have been achieved by using the transducers with the flexure flanges compared with the transducer with a rigid ring-type flange, and thus the ultrasonic transmission efficiency can be improved through the flexure flanges.

A Doubly-Curved Piezoelectric Composite with 1-3 Connectivity for Underwater Transducer Applications

Science.gov (United States)

Zhang, Yanjun; Wang, Likun; Qin, Lei; Liao, Qingwei; Zhong, Chao

2018-03-01

Aim to increase the horizontal and vertical beam width of the high frequency transducer simultaneously, we present a doubly-curved 1-3 piezoelectric composite element. It consists of 54% piezoelectric ceramic volume fraction and two phases polymer matrix. The finite element analysis (FEA) is used to evaluate the dynamic response of composite. Electroacoustic response in water was measured for the doubly-curved composite being considered as underwater transducer. An underwater transducer was fabricated using the doubly-curved 1-3 piezoelectric composite element. The -3 dB full angle beam width of transducer is approximately 106° and 36° in the horizontal and vertical plane respectively. Both the FEA simulations and experimental results show the potential of a broad covered area of the composite transducer in underwater environment.

BezRindas.lv biļešu tirdzniecības Android lietotne

OpenAIRE

Upītis, Reinis

2014-01-01

Kvalifikācijas darbā tiek aprakstīta autobusu biļešu tirdzniecības lietotne, kas ir paredzēta viedtālruņiem ar Android operētājsistēmu. Mobilā lietotne paredzēta kā papildinājums jau esošam servisam – Bezrindas.lv. Aprakstītās sistēmas izveide atvieglotu biļešu iegādi lietotājiem, kas to vēlētos darīt ar saviem viedtālruņiem.

Thermal energy harvesters with piezoelectric or electrostatic transducer

Science.gov (United States)

Prokaryn, Piotr; Domański, Krzysztof; Marchewka, Michał; Tomaszewski, Daniel; Grabiec, Piotr; Puscasu, Onoriu; Monfray, Stéphane; Skotnicki, Thomas

2014-08-01

This paper describes the idea of the energy harvester which converts thermal gradient present in environment into electricity. Two kinds of such devices are proposed and their prototypes are shown and discussed. The main parts of harvesters are bimetallic spring, piezoelectric transducer or electrostatic transducer with electret. The applied piezomembrane was commercial available product but electrets was made by authors. In the paper a fabrication procedure of electrets formed by the corona discharge process is described. Devices were compared in terms of generated power, charging current, and the voltage across a storage capacitor.

Power doppler 'blanching' after the application of transducer pressure

International Nuclear Information System (INIS)

Joshua, F.; Edmonds, J.; Lassere, M.; De Carle, R.; Rayment, M.; Bryant, C.; Shnier, R.

2005-01-01

The aim of this study was to determine if transducer pressure modifies power Doppler assessments of rheumatoid arthritis synovium at the metacarpophalangeal joints and metatarsophalangeal joints. Five rheumatoid arthritis patients of varying degrees of 'disease activity' and damage were assessed with power Doppler ultrasound scanning of the dominant hand second to fifth metacarpophalangeal joints. Two rheumatoid arthritis patients had their dominant foot first to fifth metatarsophalangeal joints assessed with power Doppler ultrasound. Ultrasonography was performed with a high frequency transducer (14 MHz) with a colour mode frequency of 10 Mhz, and a standard colour box and gain. In the joint that showed the highest power Doppler signal, an image was made. A further image was taken after transducer pressure was applied. In all patients, there was increased flow to at least one joint. After pressure was applied, power Doppler signal intensity markedly reduced in all images and in some there was no recordable power Doppler signal. Increased transducer pressure can result in a marked reduction or obliteration in power Doppler signal. This power Doppler 'blanching' shows the need for further studies to evaluate sources of error and standardization before power Doppler ultrasound becomes a routine measure of 'disease activity' in rheumatoid arthritis. Copyright (2005) Blackwell Science Pty Ltd

Enhancing endosomal escape of transduced proteins by photochemical internalisation.

Directory of Open Access Journals (Sweden)

Kevin Mellert

Full Text Available Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

Enhancing endosomal escape of transduced proteins by photochemical internalisation.

Science.gov (United States)

Mellert, Kevin; Lamla, Markus; Scheffzek, Klaus; Wittig, Rainer; Kaufmann, Dieter

2012-01-01

Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin) into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI) treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP) mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

Electromechanical characteristics of discal piezoelectric transducers with spiral interdigitated electrodes

International Nuclear Information System (INIS)

Pan, Chengliang; Xiao, Guangjun; Feng, Zhihua; Liao, Wei-Hsin

2014-01-01

In this study, piezoceramic thin disks with spiral interdigitated electrodes on their surfaces are proposed to generate in-plane torsional vibrations. Electromechanical characteristics of the discal piezoelectric transducers are investigated. Working principles of the transducers are explained while their static deformations are formulated. Dynamic models are derived to analyze the in-plane torsional vibrations of the disks together with the radial vibrations. The corresponding electromechanical equivalent circuits are also obtained. With different boundary conditions and structural parameters, frequency responses of their electric admittances are calculated numerically. Resonant frequencies, mode shapes, and electromechanical coupling coefficients of the vibration modes are also extracted. Prototype transducers are fabricated and tested to validate the theoretical results. (paper)

Neural Network Based Real-time Correction of Transducer Dynamic Errors

Science.gov (United States)

Roj, J.

2013-12-01

In order to carry out real-time dynamic error correction of transducers described by a linear differential equation, a novel recurrent neural network was developed. The network structure is based on solving this equation with respect to the input quantity when using the state variables. It is shown that such a real-time correction can be carried out using simple linear perceptrons. Due to the use of a neural technique, knowledge of the dynamic parameters of the transducer is not necessary. Theoretical considerations are illustrated by the results of simulation studies performed for the modeled second order transducer. The most important properties of the neural dynamic error correction, when emphasizing the fundamental advantages and disadvantages, are discussed.

Investigation of transducers for large-scale cryogenic systems in Italy

International Nuclear Information System (INIS)

Pavese, F.

1984-01-01

This chapter investigates temperature, pressure (static, absolute), strain and flowrate transducers. A modular cryostat system, which includes a superconducting solenoid, is used for measurements. The module for pressure transducers allows them to be measured one at a time. Adiabatic conditions for the functional part of the module for strain-gages are ensured by sliding thermal anchors. The equipment is driven by three computer-based systems which act separately. Magnetoresistance has been measured up to 6 T. Only foil-type strain gages were investigated. It is determined that apparent strain has a peculiar trend at liquid helium temperatures. Four types of transducers, specifically designed for low-temperature measurement of static, absolute pressure, and uncalibrated, were tested

INFLUENCE OF PIEZOELECTRIC TRANSDUCER TO GLASS FIBER REINFORCED COMPOSITE STIFFNESS

Directory of Open Access Journals (Sweden)

Witold Rządkowski

2015-08-01

Full Text Available The main goal was to determine if transducers based on piezoelectric materials are suitable for strain calculations in thin GFRP specimens. Numerous experimental studies, both physical and numerical, performed by the authors, have shown that there is a huge influence of bonded piezoelectric transducer on the overall stiffness of the measured object. The paper presents tensile test performed on strength machine with Digital Image Correlation strain and deflection observations. Test were compared with FEM models for detailed investigation. The main conclusion is piezoelectric transducers has huge influence on local stiffness of measured object. That is critical especially when they are used as strain sensors, when presence of sensor is influencing to measured results.

Measurement of two-phase flow momentum with force transducers

International Nuclear Information System (INIS)

Hardy, J.E.; Smith, J.E.

1990-01-01

Two strain-gage-based drag transducers were developed to measure two-phase flow in simulated pressurized water reactor (PWR) test facilities. One transducer, a drag body (DB), was designed to measure the bidirectional average momentum flux passing through an end box. The second drag sensor, a break through detector (BTD), was designed to sense liquid downflow from the upper plenum to the core region. After prototype sensors passed numerous acceptance tests, transducers were fabricated and installed in two experimental test facilities, one in Japan and one in West Germany. High-quality data were extracted from both the DBs and BTDs for a variety of loss-of-coolant accident (LOCA) scenarios. The information collected from these sensors has added to the understanding of the thermohydraulic phenomena that occur during the refill/reflood stage of a LOCA in a PWR. 9 refs., 15 figs

Implications of Dynamic Pressure Transducer Mounting Variations on Measurements in Pyrotechnic Test Apparatus

Science.gov (United States)

Dibbern, Andreas; Crisafulli, Jeffrey; Hagopia, Michael; McDougle, Stephen H.; Saulsberry, Regor L.

2009-01-01

Accurate dynamic pressure measurements are often difficult to make within small pyrotechnic devices, and transducer mounting difficulties can cause data anomalies that lead to erroneous conclusions. Delayed initial pressure response followed by data ringing has been observed when using miniaturized pressure transducer mounting adapters required to interface transducers to small test chambers. This delayed pressure response and ringing, combined with a high data acquisition rate, has complicated data analysis. This paper compares the output signal characteristics from different pressure transducer mounting options, where the passage distance from the transducer face to the pyrotechnic chamber is varied in length and diameter. By analyzing the data and understating the associated system dynamics, a more realistic understanding of the actual dynamic pressure variations is achieved. Three pressure transducer mounting configurations (elongated, standard, and face/flush mount) were simultaneously tested using NASA standard initiators in closed volume pressure bombs. This paper also presents results of these pressure transducer mounting configurations as a result of a larger NASA Engineering and Safety Center pyrovalve test project. Results from these tests indicate the improved performance of using face/flush mounted pressure transducers in this application. This type of mounting improved initial pressure measurement response time by approximately 19 s over standard adapter mounting, eliminating most of the lag time; provided a near step-function type initial pressure increase; and greatly reduced data ringing in high data acquisition rate systems. The paper goes on to discuss other issues associated with the firing and instrumentation that are important for the tester to understand.

Preparation and characterization of thin transducer layers sensitive to free chlorine in water

Czech Academy of Sciences Publication Activity Database

Kašík, Ivan; Mrázek, Jan; Podrazký, Ondřej; Seidl, Miroslav; Aubrecht, Jan; Tobiška, Petr; Matějec, Vlastimil; Kovács, B.; Markovics, A.; Szili, M.; Vlčková, K.

2008-01-01

Roč. 28, 5/6 (2008), s. 842-847 ISSN 0928-4931. [Journees Maghreb-Europe sur les Materiaux et Leurs Applications aux Dispositifs et Capteurs MADICA 2006 /5./. Mahdia, 30.10.2006-01.11.2006] R&D Projects: GA ČR(CZ) GA102/05/0948 Institutional research plan: CEZ:AV0Z20670512 Keywords : chlorine * transducers * electrochemistry Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.812, year: 2008

A Dual-Range Strain Gage Weighing Transducer Employing Automatic Switching

Science.gov (United States)

Rodger A. Arola

1968-01-01

Describes a dual-range strain gage transducer which has proven to be an excellent weight-sensing device for weighing trees and tree-length logs; discusses basic principals of the design and operation; and shows that a single transducer having two sensitivity ranges with automatic internal switching can sense weight with good repeatability and that one calibration curve...

Calculation of acoustic field based on laser-measured vibration velocities on ultrasonic transducer surface

Science.gov (United States)

Hu, Liang; Zhao, Nannan; Gao, Zhijian; Mao, Kai; Chen, Wenyu; Fu, Xin

2018-05-01

Determination of the distribution of a generated acoustic field is valuable for studying ultrasonic transducers, including providing the guidance for transducer design and the basis for analyzing their performance, etc. A method calculating the acoustic field based on laser-measured vibration velocities on the ultrasonic transducer surface is proposed in this paper. Without knowing the inner structure of the transducer, the acoustic field outside it can be calculated by solving the governing partial differential equation (PDE) of the field based on the specified boundary conditions (BCs). In our study, the BC on the transducer surface, i.e. the distribution of the vibration velocity on the surface, is accurately determined by laser scanning measurement of discrete points and follows a data fitting computation. In addition, to ensure the calculation accuracy for the whole field even in an inhomogeneous medium, a finite element method is used to solve the governing PDE based on the mixed BCs, including the discretely measured velocity data and other specified BCs. The method is firstly validated on numerical piezoelectric transducer models. The acoustic pressure distributions generated by a transducer operating in an homogeneous and inhomogeneous medium, respectively, are both calculated by the proposed method and compared with the results from other existing methods. Then, the method is further experimentally validated with two actual ultrasonic transducers used for flow measurement in our lab. The amplitude change of the output voltage signal from the receiver transducer due to changing the relative position of the two transducers is calculated by the proposed method and compared with the experimental data. This method can also provide the basis for complex multi-physical coupling computations where the effect of the acoustic field should be taken into account.

Positioning calibration apparatus for transducers employed in nuclear reactor vessel inspection apparatus

International Nuclear Information System (INIS)

Elsner, H.J.

1979-01-01

Calibration apparatus for verifying the position and orientation of transducers used in nuclear reactor vessel inspection apparatus is disclosed. A tank, filled with water, the operating inspection medium, is fitted with a movable mounting assembly adapted to securely accommodate a transducer and the mounting assembly in which it is normally secured during an inspection procedure. The tank is also provided with a slidably mounted target positioned therein at a predetermined distance from the target which is selected to avoid the distortion effects in the near field of the transducer response. The calibration apparatus can be used to check the normal transducer mounting for either perpendicularity or angular orientation by moving the tank's mounting assembly via a lead screw with which it is threadingly engaged. 6 claims

Overexpression of thioredoxin in islets transduced by a lentiviral vector prolongs graft survival in autoimmune diabetic NOD mice

Directory of Open Access Journals (Sweden)

Sytwu Huey-Kang

2009-08-01

Full Text Available Abstract Pancreatic islet transplantation is considered an appropriate treatment to achieve insulin independence in type I diabetic patients. However, islet isolation and transplantation-induced oxidative stress and autoimmune-mediated destruction are still the major obstacles to the long-term survival of graft islets in this potential therapy. To protect islet grafts from inflammatory damage and prolong their survival, we transduced islets with an antioxidative gene thioredoxin (TRX using a lentiviral vector before transplantation. We hypothesized that the overexpression of TRX in islets would prolong islet graft survival when transplanted into diabetic non-obese diabetic (NOD mice. Methods Islets were isolated from NOD mice and transduced with lentivirus carrying TRX (Lt-TRX or enhanced green fluorescence protein (Lt-eGFP, respectively. Transduced islets were transplanted under the left kidney capsule of female diabetic NOD mice, and blood glucose concentration was monitored daily after transplantation. The histology of the islet graft was assessed at the end of the study. The protective effect of TRX on islets was investigated. Results The lentiviral vector effectively transduced islets without altering the glucose-stimulating insulin-secretory function of islets. Overexpression of TRX in islets reduced hydrogen peroxide-induced cytotoxicity in vitro. After transplantation into diabetic NOD mice, euglycemia was maintained for significantly longer in Lt-TRX-transduced islets than in Lt-eGFP-transduced islets; the mean graft survival was 18 vs. 6.5 days (n = 9 and 10, respectively, p Conclusion We successfully transduced the TRX gene into islets and demonstrated that these genetically modified grafts are resistant to inflammatory insult and survived longer in diabetic recipients. Our results further support the concept that the reactive oxygen species (ROS scavenger and antiapoptotic functions of TRX are critical to islet survival after

Stress Sensors and Signal Transducers in Cyanobacteria

Science.gov (United States)

Los, Dmitry A.; Zorina, Anna; Sinetova, Maria; Kryazhov, Sergey; Mironov, Kirill; Zinchenko, Vladislav V.

2010-01-01

In living cells, the perception of environmental stress and the subsequent transduction of stress signals are primary events in the acclimation to changes in the environment. Some molecular sensors and transducers of environmental stress cannot be identified by traditional and conventional methods. Based on genomic information, a systematic approach has been applied to the solution of this problem in cyanobacteria, involving mutagenesis of potential sensors and signal transducers in combination with DNA microarray analyses for the genome-wide expression of genes. Forty-five genes for the histidine kinases (Hiks), 12 genes for serine-threonine protein kinases (Spks), 42 genes for response regulators (Rres), seven genes for RNA polymerase sigma factors, and nearly 70 genes for transcription factors have been successfully inactivated by targeted mutagenesis in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Screening of mutant libraries by genome-wide DNA microarray analysis under various stress and non-stress conditions has allowed identification of proteins that perceive and transduce signals of environmental stress. Here we summarize recent progress in the identification of sensory and regulatory systems, including Hiks, Rres, Spks, sigma factors, transcription factors, and the role of genomic DNA supercoiling in the regulation of the responses of cyanobacterial cells to various types of stress. PMID:22294932

A laboratory device for evaluation and study in the filed of ultrasonic transducers

International Nuclear Information System (INIS)

Vasiliu, S.

1978-12-01

A laboratory device for evaluation of the ultrasonic transducers, in view of adequate selection according to the testing requirements is presented. Recordings of ultrasonic beam of some transducers delivered as being of the same type are presented, showing important departures from specifications of the characteristics. Some of transducers evaluated have not been found acceptable for NDT in the nuclear field. (author)

Angle transducer based on fiber Bragg gratings able for tunnel auscultation

Science.gov (United States)

Quintela, A.; Lázaro, J. M.; Quintela, M. A.; Mirapeix, J.; Muñoz-Berti, V.; López-Higuera, J. M.

2010-09-01

In this paper an angle transducer based on Fiber Bragg Grating (FBG) is presented. Two gratings are glued to a metallic platen, one in each side. It is insensitive to temperature changes, given that the temperature shifts affect equally to both FBG. When the platen is uniformly bent an uniform strain appears in both sides of the platen. It depends on the bend angle and the platen length and thickness. The transducer has been designed to be used in the auscultation of tunnels during their construction process and during their live time. The transducer design and its characterization are presented.

Preoperative 5-FU, low-dose leucovorin, and radiation therapy for locally advanced and unresectable rectal cancer

International Nuclear Information System (INIS)

Minsky, Bruce D.; Cohen, Alfred M.; Enker, Warren E.; Saltz, Leonard; Guillem, Jose G.; Paty, Philip B.; Kelsen, David P.; Kemeny, Nancy; Ilson, David; Bass, Joanne; Conti, John

1997-01-01

Purpose: We report the local control and survival of two Phase I dose escalation trials of combined preoperative 5-fluorouracil (5-FU), low-dose leucovorin (LV), and radiation therapy followed by postoperative LV/5-FU for the treatment of patients with locally advanced and unresectable rectal cancer. Methods and Materials: A total of 36 patients (30 primary and 6 recurrent) received two monthly cycles of LV/5-FU (bolus daily x 5). Radiation therapy (50.40 Gy) began on day 1 in the 25 patients who received concurrent treatment and on day 8 in the 11 patients who received sequential treatment. Postoperatively, patients received a median of four monthly cycles of LV/5-FU. Results: The resectability rate with negative margins was 97%. The complete response rate was 11% pathologic and 14% clinical for a total of 25%. The 4-year actuarial disease-free survival was 67% and the overall survival was 76%. The crude local failure rate was 14% and the 4-year actuarial local failure rate was 30%. Crude local failure was lower in the four patients who had a pathologic complete response (0%) compared with those who either did not have a pathologic complete response (16%) or who had a clinical complete response (20%). Conclusion: Our preliminary data with the low-dose LV regimen reveal encouraging downstaging, local control, and survival rates. Additional follow-up is needed to determine the 5-year results. The benefit of downstaging on local control is greatest in patients who achieve a pathologic complete response

Initial Design and Quick Analysis of SAW Ultra–Wideband HFM Transducers

Directory of Open Access Journals (Sweden)

A. Janeliauskas

2017-09-01

Full Text Available This paper presents techniques for initial design and quick fundamental and harmonic operation analysis of surface acoustic waves ultra–wideband hyperbolically frequency modulated (HFM interdigital transducer (IDT. The primary analysis is based on the quasi–static method. Quasi–electrostatic charge's density distribution was approximated by Chebyshev polynomials and the method of Green’s function. It assesses the non uniform charge distribution of electrodes, electric field interaction and the end effects of a whole transducer. It was found that numerical integration (e.g. Romberg, Gauss–Chebyshev requires a lot of machine time for calculation of the Chebyshev polynomial and the Green’s function convolution when integration includes coordinates of a large number of neighboring electrodes. In order to accelerate the charge density calculation, the analytic expressions are derived. Evaluation of HFM transducer fundamental and harmonics' operation amplitude response with simulation single–dispersive interdigital chirp filter structure is presented. Elapsed time of HFM IDT with 589 electrodes simulations and 2000 frequency response point is only 54 seconds (0.027 s/point on PC with CPU Intel Core I7–4770S. Amplitude response is compared with linear frequency modulated (LFM IDT response. It was determined that the HFM transducer characteristic is less distorted in comparison with LFM transducer.

LMO1 Synergizes with MYCN to Promote Neuroblastoma Initiation and Metastasis.

Science.gov (United States)

Zhu, Shizhen; Zhang, Xiaoling; Weichert-Leahey, Nina; Dong, Zhiwei; Zhang, Cheng; Lopez, Gonzalo; Tao, Ting; He, Shuning; Wood, Andrew C; Oldridge, Derek; Ung, Choong Yong; van Ree, Janine H; Khan, Amish; Salazar, Brittany M; Lummertz da Rocha, Edroaldo; Zimmerman, Mark W; Guo, Feng; Cao, Hong; Hou, Xiaonan; Weroha, S John; Perez-Atayde, Antonio R; Neuberg, Donna S; Meves, Alexander; McNiven, Mark A; van Deursen, Jan M; Li, Hu; Maris, John M; Look, A Thomas

2017-09-11

A genome-wide association study identified LMO1, which encodes an LIM-domain-only transcriptional cofactor, as a neuroblastoma susceptibility gene that functions as an oncogene in high-risk neuroblastoma. Here we show that dβh promoter-mediated expression of LMO1 in zebrafish synergizes with MYCN to increase the proliferation of hyperplastic sympathoadrenal precursor cells, leading to a reduced latency and increased penetrance of neuroblastomagenesis. The transgenic expression of LMO1 also promoted hematogenous dissemination and distant metastasis, which was linked to neuroblastoma cell invasion and migration, and elevated expression levels of genes affecting tumor cell-extracellular matrix interaction, including loxl3, itga2b, itga3, and itga5. Our results provide in vivo validation of LMO1 as an important oncogene that promotes neuroblastoma initiation, progression, and widespread metastatic dissemination. Copyright © 2017 Elsevier Inc. All rights reserved.

Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

Science.gov (United States)

Reinhardt, Brian; Tittmann, Bernhard; Rempe, Joy; Daw, Joshua; Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov; Ramuhalli, Pradeep; Montgomery, Robert; Chien, Hualte; Wernsman, Bernard

2015-03-01

Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

Energy Technology Data Exchange (ETDEWEB)

Reinhardt, Brian; Tittmann, Bernhard [The Pennsylvania State University (United States); Rempe, Joy; Daw, Joshua [Idaho National Laboratory (United States); Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov [Massachusetts Institute of Technology (United States); Ramuhalli, Pradeep; Montgomery, Robert [Pacific Northwest National Laboratory (United States); Chien, Hualte [Argonne National Laboratory (United States); Wernsman, Bernard [Bechtel Marine Propulsion Corp (United States)

2015-03-31

Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

Structural remodeling of the heart and its premotor cardioinhibitory vagal neurons following T(5) spinal cord transection.

Science.gov (United States)

Lujan, Heidi L; Janbaih, Hussein; DiCarlo, Stephen E

2014-05-01

Midthoracic spinal cord injury (SCI) is associated with enhanced cardiac sympathetic activity and reduced cardiac parasympathetic activity. The enhanced cardiac sympathetic activity is associated with sympathetic structural plasticity within the stellate ganglia, spinal cord segments T1-T4, and heart. However, changes to cardiac parasympathetic centers rostral to an experimental SCI are relatively unknown. Importantly, reduced vagal activity is a predictor of high mortality. Furthermore, this autonomic dysregulation promotes progressive left ventricular (LV) structural remodeling. Accordingly, we hypothesized that midthoracic spinal cord injury is associated with structural plasticity in premotor (preganglionic parasympathetic neurons) cardioinhibitory vagal neurons located within the nucleus ambiguus as well as LV structural remodeling. To test this hypothesis, dendritic arborization and morphology (cholera toxin B immunohistochemistry and Sholl analysis) of cardiac projecting premotor cardioinhibitory vagal neurons located within the nucleus ambiguus were determined in intact (sham transected) and thoracic level 5 transected (T5X) rats. In addition, LV chamber size, wall thickness, and collagen content (Masson trichrome stain and structural analysis) were determined. Midthoracic SCI was associated with structural changes within the nucleus ambiguus and heart. Specifically, following T5 spinal cord transection, there was a significant increase in cardiac parasympathetic preganglionic neuron dendritic arborization, soma area, maximum dendritic length, and number of intersections/animal. This parasympathetic structural remodeling was associated with a profound LV structural remodeling. Specifically, T5 spinal cord transection increased LV chamber area, reduced LV wall thickness, and increased collagen content. Accordingly, results document a dynamic interaction between the heart and its parasympathetic innervation.

Actuators, transducers and motors based on giant magnetostrictive materials

Energy Technology Data Exchange (ETDEWEB)

Claeyssen, F.; Lhermet, N.; Le Letty, R. [Cedrat Recherche, Meylan (France); Bouchilloux, P. [Magsoft Corporation, 1223 People`s Avenue, New York 12180 (United States)

1997-08-01

Rare earth-iron magnetostrictive alloys, especially Terfenol-D, feature ``giant`` magnetostrains: static strains of 1000-2000 ppm and dynamic strains of 3500 ppm are reported. These strains permit building various actuating devices (actuators, transducers, motors) both at macro and micro scale. The object of the paper is to recall adapted design methods, especially finite element methods such as ATILA, and to review these different kinds of devices studied at Cedrat Recherche, providing both up-dated experimental and numerical results. The presented devices will include several large displacement longitudinal and shear actuators biased using permanent magnets and used either as characterisation devices or as electromechanical actuators (for active damping, for sonar transducers..), a 1 kHz 4 kW Tonpilz-type sonar transducer called the tripode, a 2 N m torque rotating multi-mode motor, a torsion based drift free micro actuator and a wireless linear micromotor. (orig.)

Phased transducer array for acoustic energy harvesting inside an MRI machine

NARCIS (Netherlands)

Klymko, V.; Roes, M.G.L.; Duivenbode, van J.; Lomonova, E.

2013-01-01

In this study, an array of piezoelectric speakers is used to focus acoustic energy on a single transducer that acts as a harvester. The transmitting transducers are located along a curve that fits inside the magnetic resonance interferometer (MRI) torus interior. The numerical results for the

Development of transducers for integrated garter spring repositioning system

Energy Technology Data Exchange (ETDEWEB)

Sharma, B S.V.G.; Shyam, T V; Shrivastava, A K; Rupani, B B; Sinha, R K [Bhabha Atomic Research Centre, Bombay (India). Reactor Engineering Div.

1994-12-31

In order to reposition the dislocated garter springs in active channels of 235 MW Pressurised Heavy Water Reactors (PHWRs), a tool named as Integrated Garter Spring Repositioning System (INGRES) has been developed. The tool consists of transducers to detect the concentricity between the Pressure Tube (P/T) and Calandria Tube (C/T) and also to detect garter springs in the channel besides different modules for correcting the eccentricity between P/T and C/T and garter spring repositioning. The transducers used in the system namely Concentricity Detection Probe (CDP) and Garter Spring Detection Probe (GSDP) are based on the eddy current techniques. The CDP makes use of four eddy current bobbin probes separated 90 degrees apart in cross sectional plane of channel assembly. The transducer gives output signal in proportional to the air gap between P/T and C/T in two axes (X and Y) which are designed for the purpose. The output of the unit is obtained on the Cathode Ray Oscilloscope (CRO) screen in the form of illuminated dot. The dot position on the CRO screen gives the information about mismatch in concentricity between P/T and C/T of the channel. The GSDP meant for detecting garter springs in PHWR channel uses two sets of primary and secondary coils connected in differential mode. The output signals from the transducers are processed through a signal processing unit devised for the purpose to obtain output from it as a horizontal beam on the CRO screen. The garter spring presence in the channel is indicated by a change in the voltage level of beam and also by audio-visual indication in the form of buzzer and LED illumination on the processing unit. This paper gives general design and development aspects of the CDP and GSDP transducers of the INGRES tool. (author). 3 figs.

HIFU Transducer Characterization Using a Robust Needle Hydrophone

Science.gov (United States)

Howard, Samuel M.; Zanelli, Claudio I.

2007-05-01

A robust needle hydrophone has been developed for HIFU transducer characterization and reported on earlier. After a brief review of the hydrophone design and performance, we demonstrate its use to characterize a 1.5 MHz, 10 cm diameter, F-number 1.5 spherically focused source driven to exceed an intensity of 1400 W/cm2at its focus. Quantitative characterization of this source at high powers is assisted by deconvolving the hydrophone's calibrated frequency response in order to accurately reflect the contribution of harmonics generated by nonlinear propagation in the water testing environment. Results are compared to measurements with a membrane hydrophone at 0.3% duty cycle and to theoretical calculations, using measurements of the field at the source's radiating surface as input to a numerical solution of the KZK equation.

Acoustic Levitation With One Transducer

Science.gov (United States)

Barmatz, Martin B.

1987-01-01

Higher resonator modes enables simplification of equipment. Experimental acoustic levitator for high-temperature containerless processing has round cylindrical levitation chamber and only one acoustic transducer. Stable levitation of solid particle or liquid drop achieved by exciting sound in chamber to higher-order resonant mode that makes potential well for levitated particle or drop at some point within chamber.

Proceedings of transducer 84 conference

Energy Technology Data Exchange (ETDEWEB)

1984-01-01

In the broad and varied field of sensors this conference reviews thermal sensors for temperature measurements, gas sensors for gas analysis (for example analysis of exhaust gases from vehicles), optical fiber sensors, applications for optics, mechanics, robotics and signal processing. In particular one of the applications concerns acoustical transducers operating in liquid sodium for LMFBR reactors.

Accuracy of soil stress measurements as affected by transducer dimensions and shape

DEFF Research Database (Denmark)

Lamandé, Mathieu; Keller, Thomas; Berisso, Feto Esimo

2015-01-01

Accurate measurements of soil stress are needed to evaluate the impact of traffic on soil properties and prevent soil compaction. Four types of transducer commonly used to measure vertical stress were calibrated in realistic traffic conditions in the field. The four transducer types differed...... in shape and dimensions, which are important factors influencing stress. Deviation of measured stress from true stress ranged from 15% underestimation to 18% overestimation, with transducer thickness to width ratio being the most important shape factor influencing the stress recorded. Changes in physical...... conditions in the soil above the transducers due to their installation did not influence the accuracy of vertical stress measurements. The results of this calibration are valid for correcting stress measurements in topsoil, but should be used with caution for vertical stress measurements in subsoil. All...

Improving the Design of Capacitive Micromachined Ultrasonic Transducers Aided with Sensitivity Analysis

Directory of Open Access Journals (Sweden)

A Martowicz

2016-09-01

Full Text Available The paper presents the results of analysis performed to search for feasible design improvements for capacitive micromachined ultrasonic transducer. Carried out search has been aided with the sensitivity analysis and the application of Response Surface Method. The multiphysics approach has been taken into account in elaborated finite element model of one cell of described transducer in order to include significant physical phenomena present in modelled microdevice. The set of twelve input uncertain and design parameters consists of geometric, material and control properties. The amplitude of dynamic membrane deformation of the transducer has been chosen as studied parameter. The objective of performed study has been defined as the task of finding robust design configurations of the transducer, i.e. characterizing maximal value of deformation amplitude with its minimal variation.

Crossed SMPS MOSFET-based protection circuit for high frequency ultrasound transceivers and transducers.

Science.gov (United States)

Choi, Hojong; Shung, K Kirk

2014-06-12

The ultrasonic transducer is one of the core components of ultrasound systems, and the transducer's sensitivity is significantly related the loss of electronic components such as the transmitter, receiver, and protection circuit. In an ultrasonic device, protection circuits are commonly used to isolate the electrical noise between an ultrasound transmitter and transducer and to minimize unwanted discharged pulses in order to protect the ultrasound receiver. However, the performance of the protection circuit and transceiver obviously degrade as the operating frequency or voltage increases. We therefore developed a crossed SMPS (Switching Mode Power Supply) MOSFET-based protection circuit in order to maximize the sensitivity of high frequency transducers in ultrasound systems.The high frequency pulse signals need to trigger the transducer, and high frequency pulse signals must be received by the transducer. We therefore selected the SMPS MOSFET, which is the main component of the protection circuit, to minimize the loss in high frequency operation. The crossed configuration of the protection circuit can drive balanced bipolar high voltage signals from the pulser and transfer the balanced low voltage echo signals from the transducer. The equivalent circuit models of the SMPS MOSFET-based protection circuit are shown in order to select the proper device components. The schematic diagram and operation mechanism of the protection circuit is provided to show how the protection circuit is constructed. The P-Spice circuit simulation was also performed in order to estimate the performance of the crossed MOSFET-based protection circuit. We compared the performance of our crossed SMPS MOSFET-based protection circuit with a commercial diode-based protection circuit. At 60 MHz, our expander and limiter circuits have lower insertion loss than the commercial diode-based circuits. The pulse-echo test is typical method to evaluate the sensitivity of ultrasonic transducers

Fundamentals for remote structural health monitoring of wind turbine blades - a preproject. Annex C. Fibre transducer for damage detection in adhesive layers of wind turbine blades

DEFF Research Database (Denmark)

Sendrup, P.

2002-01-01

displacement transducer for detection of damage in adhesive layers of wind turbine blades. It was chosen to base the transducer on the fibre optic micro-bend principle. The report contains the result of measurementsand optical simulations of light transmittance through optical fibres with micro......-bends and a suggestion for a micro-bend transducer design specifically suitable for detection of damage in adhesive layers between larger composite structures, as the shellsin a wind turbine blade. Such a damage will cause the joined parts to move slightly relative to each other, and the transducer is designed to change...... optic micro-bend transducer would be in the range between0.5%/um to 1 %/um depending on the number of bends on the fibre. A measurement on the final transducer showed that the sensitivity was 1.2 %/um. A large 50 % change in transmittance, that is easy to measure, is then obtained for displacements...

Impact of Distributed Generation Grid Code Requirements on Islanding Detection in LV Networks

Directory of Open Access Journals (Sweden)

Fabio Bignucolo

2017-01-01

Full Text Available The recent growing diffusion of dispersed generation in low voltage (LV distribution networks is entailing new rules to make local generators participate in network stability. Consequently, national and international grid codes, which define the connection rules for stability and safety of electrical power systems, have been updated requiring distributed generators and electrical storage systems to supply stabilizing contributions. In this scenario, specific attention to the uncontrolled islanding issue has to be addressed since currently required anti-islanding protection systems, based on relays locally measuring voltage and frequency, could no longer be suitable. In this paper, the effects on the interface protection performance of different LV generators’ stabilizing functions are analysed. The study takes into account existing requirements, such as the generators’ active power regulation (according to the measured frequency and reactive power regulation (depending on the local measured voltage. In addition, the paper focuses on other stabilizing features under discussion, derived from the medium voltage (MV distribution network grid codes or proposed in the literature, such as fast voltage support (FVS and inertia emulation. Stabilizing functions have been reproduced in the DIgSILENT PowerFactory 2016 software environment, making use of its native programming language. Later, they are tested both alone and together, aiming to obtain a comprehensive analysis on their impact on the anti-islanding protection effectiveness. Through dynamic simulations in several network scenarios the paper demonstrates the detrimental impact that such stabilizing regulations may have on loss-of-main protection effectiveness, leading to an increased risk of unintentional islanding.

An NLRA Transducer for Dual Use Bone Conduction Audio and Haptic Communication. Summary Report

Science.gov (United States)

2016-12-30

100 gram proof mass , was approximately 1G tap and 1.5G sustained vibration. While we were unable to accommodate a detailed quantitative evaluation of...the acoustic operating mode within the Phase 1 budget, the transducer was capable of transmitting intelligible voice and good fidelity music playback at

Failure Analysis of High-Power Piezoelectric Transducers

National Research Council Canada - National Science Library

Gabrielson, T. B

2005-01-01

... and stress in a piezoelectric material. For a transducer operated near resonance, there will be "hot spots" or regions of locally intense stress and electric field that precipitate premature failure...

The Effects of Curcuma longa L., Purple Sweet Potato, and Mixtures of the Two on Immunomodulation in C57BL/6J Mice Infected with LP-BM5 Murine Leukemia Retrovirus.

Science.gov (United States)

Park, Soo-Jeung; Lee, Dasom; Lee, Minhee; Kwon, Han-Ol; Kim, Hyesook; Park, Jeongjin; Jeon, Woojin; Cha, Minseok; Jun, Suhwa; Park, Kwangjin; Lee, Jeongmin

2018-06-04

The immune response is stimulated to protect the body from external antigens and is controlled by several types of immune cells. In the present study, the immunomodulatory effects of Curcuma longa L., purple sweet potato, and mixtures of the two (CPM) were investigated in C57BL/6 mice infected with LP-BM5 murine leukemia virus (MuLV). Mice were divided into seven groups as follows: normal control, infected control (LP-BM5 MuLV infection), positive control (LP-BM5 MuLV infection+dietary supplement of red ginseng 300 mg/kg body weight), the original powder of C. longa L. (C; LP-BM5 MuLV infection+dietary supplement of C 189 mg/kg body weight), the original powder of purple sweet potato (P; LP-BM5 MuLV infection+dietary supplement of P 1811 mg/kg body weight), CPM Low (CPL; LP-BM5 MuLV infection+CPM 2 g/kg body weight), and CPM High (CPH; LP-BM5 MuLV infection+CPM 5 g/kg body weight). Dietary supplementation lasted for 12 weeks. Dietary supplementation of CPM inhibited LP-BM5 MuLV-induced lymphadenopathy and splenomegaly and inhibited reduction of messenger RNA (mRNA) expression of major histocompatibility complex (MHC) I and II. Moreover, CPM reduced the decrease in T- and B cell proliferation, reduced the population of CD4(+)/CD8(+) T cells, and remedied the unbalanced production of T helper-1 (Th1)/T helper-2 (Th2) cytokines in LP-BM5 MuLV-infected mice. In addition, CPM inhibited reduction of phagocytosis in peritoneal macrophages and decreased serum levels of immunoglobulin A (IgA), immunoglobulin E (IgE), and immunoglobulin G (IgG). These results suggest that CPM had a positive effect on immunomodulation in C57BL/6 mice induced by LP-BM5 leukemia retrovirus infection.

Characterization of very high frequency transducers with wire target and hydrophone

International Nuclear Information System (INIS)

Huang Bin; Shung, K Kik

2004-01-01

In this paper, the wire-target technique will be shown to be a useful alternative for beam profile measurements in very high frequency range (30-60 MHz). A 9 cm long tungsten wire with a diameter of 8 μm was used as the pulse-echo target to measure the lateral beam profiles at the focal points of two transducers, a spherically focused 40 MHz Panametrics transducer with an aperture size of 6.35 mm and a geometrical focal length of 12.7 mm and a lense-focused in-house lithium niobate (LiNbO 3 ) 60 MHz transducer with an aperture size of 2 mm and a geometrical focal length around 6.5 mm. For comparison, measurements on the same transducers were performed by three small-aperture hydrophones. The first one is a polyvinylidene fluoride trifluoroethylene (PVDF-TrFE) membrane hydrophone developed by Hewlett-Packard, which has a geometric diameter of 37 μm, a measured effective diameter of less than 100 μm and a -3 dB bandwidth of more than 150 MHz. The second one is a needle-type PVDF hydrophone from Precision Acoustics, which has a 9 μm-thick PVDF element, a 40 μm geometrical aperture and a measured effective diameter of less than 100 μm. The third one is a needle-type PVDF hydrophone from Onda, which has a 150 μm geometrical aperture and an effective diameter of about 180 μm. Experimental results show that the -6 dB two-way beam widths measured by this 8 μm wire-target are in agreement with -3 dB transmitted beam widths measured by small-aperture hydrophones. Compared to small-aperture hydrophones, the wire-target technique is simpler and more cost-effective. Its major advantage however is in the frequency range above 100 MHz in which commercial hydrophones are not yet available

Additional electrodes on the Quartet™ LV lead provide more programmable pacing options than bipolar and tripolar equivalents.

Science.gov (United States)

O'Donnell, David; Sperzel, Johannes; Thibault, Bernard; Rinaldi, Christopher A; Pappone, Carlo; Gutleben, Klaus-Jürgen; Leclercq, Christopher; Razavi, Hedi; Ryu, Kyungmoo; Mcspadden, Luke C; Fischer, Avi; Tomassoni, Gery

2017-04-01

The aim of this study was to evaluate any benefits to the number of viable pacing vectors and maximal spatial coverage with quadripolar left ventricular (LV) leads when compared with tripolar and bipolar equivalents in patients receiving cardiac resynchronization therapy (CRT). A meta-analysis of five previously published clinical trials involving the Quartet™ LV lead (St Jude Medical, St Paul, MN, USA) was performed to evaluate the number of viable pacing vectors defined as capture thresholds ≤2.5 V and no phrenic nerve stimulation and maximal spatial coverage of viable vectors in CRT patients at pre-discharge (n = 370) and first follow-up (n = 355). Bipolar and tripolar lead configurations were modelled by systematic elimination of two and one electrode(s), respectively, from the Quartet lead. The Quartet lead with its four pacing electrodes exhibited the greatest number of pacing vectors per patient when compared with the best bipolar and the best tripolar modelled equivalents. Similarly, the Quartet lead provided the highest spatial coverage in terms of the distance between two furthest viable pacing cathodes when compared with the best bipolar and the best tripolar configurations (P tripolar configurations, elimination of the second proximal electrode (M3) resulted in the highest number of viable pacing options per patient. There were no significant differences observed between pre-discharge and first follow-up analyses. The Quartet lead with its four electrodes and the capability to pace from four anatomical locations provided the highest number of viable pacing vectors at pre-discharge and first follow-up visits, providing more flexibility in device programming and enabling continuation of CRT in more patients when compared with bipolar and tripolar equivalents. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

A top-crossover-to-bottom addressed segmented annular array using piezoelectric micromachined ultrasonic transducers

Science.gov (United States)

Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Hong, Hyeryung; Yuen Song, Hi; Oh, Inn-yeal; Park, Chul Soon; Choi, Hongsoo

2015-11-01

We design and fabricate segmented annular arrays (SAAs) using piezoelectric micromachined ultrasonic transducers (pMUTs) to demonstrate the feasibility of acoustic focusing of ultrasound. The fabricated SAAs have 25 concentric top-electrode signal lines and eight bottom-electrodes for grounding to enable electronic steering of selectively grouped ultrasonic transducers from 2393 pMUT elements. Each element in the array is connected by top-crossover-to-bottom metal bridges, which reduce the parasitic capacitance. Circular-shaped pMUT elements, 120 μm in diameter, are fabricated using 1 μm-thick sol-gel lead zirconate titanate on a silicon wafer. To utilize the high-density pMUT array, a deep reactive ion etching process is used for anisotropic silicon etching to realize the transducer membranes. The resonant frequency and effective coupling coefficient of the elements, measured with an impedance analyzer, yields 1.517 MHz and 1.29%, respectively, in air. The SAAs using pMUTs are packaged on a printed circuit board and coated with parylene C for acoustic intensity measurements in water. The ultrasound generated by each segmented array is focused on a selected point in space. When a 5 Vpp, 1.5 MHz square wave is applied, the maximum spatial peak temporal average intensity ({{I}\\text{spta}} ) is found to be 79 mW cm-2 5 mm from the SAAs’ surface without beamforming. The beam widths (-3 dB) of ultrasonic radiation patterns in the elevation and azimuth directions are recorded as 3 and 3.4 mm, respectively. The results successfully show the feasibility of focusing ultrasound on a small area with SAAs using pMUTs.

Numerical implementation of magneto-acousto-electrical tomography (MAET) using a linear phased array transducer

Science.gov (United States)

Soner Gözü, Mehmet; Zengin, Reyhan; Güneri Gençer, Nevzat

2018-02-01

In this study, the performance and implementation of magneto-acousto-electrical tomography (MAET) is investigated using a linear phased array (LPA) transducer. The goal of MAET is to image the conductivity distribution in biological bodies. It uses the interaction between ultrasound and a static magnetic field to generate velocity current density distribution inside the body. The resultant voltage due to velocity current density is sensed by surface electrodes attached on the body. In this study, the theory of MAET is reviewed. A 16-element LPA transducer with 1 MHz excitation frequency is used to provide beam directivity and steerability of acoustic waves. Different two-dimensional numerical models of breast and tumour are formed to analyze the multiphysics problem coupled with acoustics and electromagnetic fields. In these models, velocity current density distributions are obtained for pulse type ultrasound excitations. The static magnetic field is assumed as 1 T. To sense the resultant voltage caused by the velocity current density, it is assumed that two electrodes are attached on the surface of the body. The performance of MAET is shown through sensitivity matrix analysis. The sensitivity matrix is obtained for two transducer positions with 13 steering angles between -30\\circ to 30\\circ with 5\\circ angular intervals. For the reconstruction of the images, truncated singular value decomposition method is used with different signal-to-noise ratio (SNR) values (20 dB, 40 dB, 60 dB and 80 dB). The resultant images show that the perturbation (5 mm  ×  5 mm) placed 35 mm depth can be detected even if the SNR is 20 dB.

Selective in vivo radiosensitization by 5-fluorocytosine of human colorectal carcinoma cells transduced with the E. coli cytosine deaminase (CD) gene

International Nuclear Information System (INIS)

Gabel, M.; Kim, J.H.; Kolozsvary, A.; Khil, M.; Freytag, S.

1998-01-01

Purpose: The E. coli cytosine deaminase (CD) gene encodes an enzyme capable of converting the nontoxic prodrug 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU), a known radiosensitizer. Having previously shown that combined CD suicide gene therapy and radiation (RT) results in pronounced radiosensitization in vitro, we progressed to in vivo studies of combined therapy. Methods and Materials: WiDr human colon cancer cells were transduced in vitro with the CD gene and cells expressing CD were selected for use as xenografts in a nude mouse model. After administration of 5-FC, tumors received 10-30 Gy local field radiation (RT) and tumor growth delay was compared to control animals receiving either 5-FU, 5-FC, or RT alone. Results: Maximal growth delay was seen in mice treated with 5-FC for 6 consecutive days prior to RT. Combined treatment with 15 Gy radiation resulted in a dose-modifying factor (DMF) of 1.50, and a greater DMF was observed with higher doses of radiation. There was no appreciable toxicity using this new approach. In contrast, a similar treatment of combined 5-FU and radiation resulted in considerable toxicity and no appreciable radiosensitization. Conclusion: The present results show that combined suicide gene therapy and RT results in pronounced antitumor effect without any notable toxicity. This indicates that the CD gene may be useful in the development of novel treatment strategies combining radiation and gene therapy in the treatment of locally advanced cancers

A rectangle-type linear ultrasonic motor using longitudinal vibration transducers with four driving feet.

Science.gov (United States)

Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

2013-04-01

To make full use of the vibrational energy of a longitudinal transducer, a rectangle-type linear ultrasonic motor with four driving feet is proposed in this paper. This new motor consists of four longitudinal vibration transducers which are arranged in a rectangle and form an enclosed construction. Lead zirconate titanate ceramics are embedded into the middle of the transducer and fastened by a wedge-caulking mechanism. Each transducer includes an exponentially shaped horn located on each end. The horns of the vertical transducers intersect at the base of the horizontal transducers' horns; the tip ends of the horizontal transducers' horns are used as the driving feet. Longitudinal vibrations are superimposed in the motor and generate elliptical movements at the tip ends of the horns. The working principle of the proposed motor is analyzed. The resonance frequencies of two working modes are tuned to be close to each other by adjusting the structural parameters. Transient analysis is developed to gain the vibration characteristics of the motor. A prototype motor is fabricated and measured. The vibration test results verify the feasibility of the proposed design. Typical output of the prototype is a no-load speed of 928 mm/s and maximum thrust force of 60 N at a voltage of 200 Vrms.

Detection and generation of first sound in4He by vibrating superleak transducers

Science.gov (United States)

Giordano, N.; Edison, N.

1986-07-01

Measurement is made of the first-sound generation and detection efficiencies of vibrating superleak transducers (VSTs) operated in superfluid4He. This is accomplished by using an ordinary pressure transducer to generate first sound with a VST as the detector, and by using a pressure transducer to detect the sound generated by a VST. The results are in reasonably good agreement with the current theory of VST operation.

Detection and generation of first sound in 4He by vibrating superleak transducers

International Nuclear Information System (INIS)

Giordano, N.; Edison, N.

1986-01-01

Measurement is made of the first-sound generation and detection efficiencies of vibrating superleak transducers (VSTs) operated in superfluid 4 He. This is accomplished by using an ordinary pressure transducer to generate first sound with a VST as the detector, and by using a pressure transducer to detect the sound generated by a VST. The results are in reasonably good agreement with the current theory of VST operation

Evaluation of pressure transducers to measure surface level in the waste storage tanks

International Nuclear Information System (INIS)

Peters, T.J.; Colson, J.B.

1994-06-01

This report describes the results of tests conducted at the Pacific Northwest Laboratory (PNL) to determine if pressure transducers can be used to measure the surface level in the waste tanks. A survey was first conducted to evaluate which, if any, commercially available pressure transducers were available that could meet the requirements for use in the waste tanks. More than 35 companies were contacted to determine if they manufactured a pressure transducer that could be used in the 101-SY waste tank. The three basic requirements for a pressure transducer for this application were that they were radiation-hardened, could withstand a caustic environment, and were certified to be intrinsically safe. No manufacturer was able to meet all three of these requirements with a commercially available product. Seven companies were able to meet the requirements for being radiation-hardened and being able to withstand the caustic environment. However, only two of the nine companies were willing to supply a pressure transducer for laboratory testing. The two pressure transducers that were tested in this program were the VEGA D36-38 from HiTech Technologies, Inc., and the KP-1911-A from Kaman Instrumentation Corporation. Pressure transducers operate on the principle that the pressure at the location of a sensor increases directly with the depth of the liquid above it. A liquid is required in order for these devices to operate. For these tests, water was first used to determine the ideal operation of the devices, then the devices were placed in a 101-SY waste tank simulant. The simulant had a specific gravity of 1.96 and had the consistency similar to the convective layer in the 101-SY waste tank. In order to determine the surface level with pressure transducers, the density of the material needs to be known

Eliminating transducer distortion in acoustic measurements

DEFF Research Database (Denmark)

Agerkvist, Finn T.; Torras Rosell, Antoni; McWalter, Richard Ian

2014-01-01

This paper investigates the in uence of nonlinear components that contaminate the linear response of acoustic transducer, and presents a method for eliminating the in uence of nonlinearities in acoustic measurements. The method is evaluated on simulated as well as experimental data, and is shown...

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration.

Science.gov (United States)

Wei, Xiaoyuan; Yang, Yuan; Yao, Wenqing; Zhang, Lei

2017-09-30

Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

Inspection of complex geometry pieces with an intelligent contact transducer

International Nuclear Information System (INIS)

Chatillon, S.; Roy, O.; Mahaut, St.

2000-01-01

A new multi-element contact transducer has been developed to improve the inspection of components with complex geometry. The emitting surface is flexible in order to optimize the contact with pieces. An algorithm, based on a simplified geometric model, has been used to determine the delays law which allows to control the focal characteristics of the transmitted field. Acquisition data lead in transmission with an articulated transducer validate the behavior provided by simulation. Thus the optimization of the delays law ensures the transmission of a beam which is homogeneous and controlled during the moving of the transducer. Inspections in echo-pulse mode are implemented on a sample simulating a component controlled on site. Results show that the dynamical adaptation of the delays law to the geometry of the piece leads to very good performances

Superconducting microwave cavity parametric converter transducer sensitive to 10-19 M harmonic motion

International Nuclear Information System (INIS)

Reece, C.E.

1984-01-01

Toward the development of a transducer suitable for the detection of high frequency gravitational effects, a superconducting microwave coupled-cavity parametric converter transducer has been analyzed, developed and tested. An analysis is presented of the intermodal parametric conversion which is produced by harmonic perturbaton of the length of a 10 GHz TE 011 mode cylindrical resonant cavity. The converter is examined as a transducer of displacement with harmonic frequency near the intermodal difference frequency. Transducer sensitivity dependence upon cavity tunings, couplings, and Q-factors is analyzed and experimentally tested with excellent agreement. The transducer consists of two identical coupled TE 011 niobium cavities with one endwall driven into mechanical oscillation by an externally mounted piezoelectric ceramic. A displacement with effective amplitude (3.7 +/- 1.3) x 10 -19 m and frequency 1.13 MHz has been observed by detecting a 10GHz conversion power of 10 -21 watts. This measurement was obtained with 0.12 mJ stored in a cavity resonance with an unloaded Q-factor of 6.7 x 10 8 at 1.55 0 K. The applications of this device in the detection of high frequency gravitational effects are also discussed. Finally, the prospects for improvement of transducer sensitivity and the ultimate limitations are presented

Effect of planecta and ROSE™ on the frequency characteristics of blood pressure-transducer kits.

Science.gov (United States)

Fujiwara, Shigeki; Kawakubo, Yoshifumi; Mori, Satoshi; Tachihara, Keiichi; Toyoguchi, Izumi; Yokoyama, Takeshi

2015-12-01

Pressure-transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE™, Argon Medical Devices, TX, USA) on the frequency characteristics of pressure-transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus transducer kit (Argon Medical Devices) were prepared with planecta ports, and their frequency characteristics were tested with or without ROSE™. The natural frequency and damping coefficient of each kit were obtained using frequency characteristics analysis software and evaluated by plotting them on the Gardner's chart. By inserting a planecta port, the natural frequency markedly decreased in both the FloTrac sensor kit (from 40 to 22 Hz) and the DTXplus transducer kit (from 35 to 22 Hz). In both kits with one planecta port, the damping coefficient markedly increased by insertion of ROSE™ from 0.2 to 0.5, optimising frequency characteristics. In both kits with two planecta ports, however, the natural frequency decreased from 22 to 12 Hz. The damping coefficient increased from 0.2 to 0.8 by insertion of ROSE™; however, optimisation was not achieved even by ROSE™ insertion. Planecta ports decrease the natural frequency of the kit. ROSE™ is useful to optimise the frequency characteristics in the kits without or with one planecta port. However, optimisation is difficult with two or more planecta ports, even with the ROSE™ device.

Supported high-risk percutaneous coronary intervention with the Impella 2.5 device the Europella registry

DEFF Research Database (Denmark)

Sjauw, Krischan D; Konorza, Thomas; Erbel, Raimund

2009-01-01

OBJECTIVES: This retrospective multicenter registry evaluated the safety and feasibility of left ventricular (LV) support with the Impella 2.5 (Abiomed Europe GmbH, Aachen, Germany) during high-risk percutaneous coronary intervention (PCI). BACKGROUND: Patients with complex or high-risk coronary...... with poor LV function. The Impella 2.5, a percutaneous implantable LV assist device, might be a superior alternative to the traditionally used intra-aortic balloon pump. METHODS: The Europella registry included 144 consecutive patients who underwent a high-risk PCI. Safety and feasibility end points.......5%. Rates of myocardial infarction, stroke, bleeding requiring transfusion/surgery, and vascular complications at 30 days were 0%, 0.7%, 6.2%, and 4.0%, respectively. CONCLUSIONS: This large multicenter registry supports the safety, feasibility, and potential usefulness of hemodynamic support with Impella 2...

Damage detection with concentrated configurations of piezoelectric transducers

International Nuclear Information System (INIS)

Wandowski, T; Malinowski, P; Ostachowicz, W M

2011-01-01

In this paper results of investigation on concentrated piezoelectric networks with different configurations are presented. They were used for elastic wave generation and acquisition. The elastic wave propagation phenomenon was used for damage localization in thin aluminium panels. This approach utilized the fact that any discontinuities existing in structural elements cause local changes of physical material properties which affect elastic wave propagation. Elastic waves were excited and received using piezoelectric transducer networks with different element arrangements. The method of transducer placement and the number of piezoelectric elements used had an influence on the accuracy of the damage localization algorithm. Obviously, the more elements there were, the more data had to be processed. After the acquisition process signal processing was conducted in order to create damage influence maps. These maps presents elastic wave energy connected with reflection from discontinuities. In order to create such a map a computer program was developed that assigns a mesh of points to the panel surface. At each point the energy of elastic wave reflection was calculated. This energy was extracted from the acquired signals. This paper summarizes an extensive experimental investigation that included three damage scenarios and twelve transducer configurations

EPMT: a portable transfer standard for telemetry system pressure-transducer calibration

International Nuclear Information System (INIS)

Hasbrouck, R.T.

1977-01-01

The LLL developed electronic pressure meter (EPMT) is a portable static-pressure calibration instrument for use with the LLL telemetry transducer system at the Nevada Test Site (NTS). It is significantly more accurate and rugged than the bourdon-tube pressure gauge it replaces, and can be incorporated into a field-use, semi-automatic, pressure calibration system. The process by which a transducer is selected for EPMT use from the inventory of field-service-certified transducers and subjected to an extensive preconditioning and calibration procedure is described. By combining this unusual calibration procedure with a unique, statistically based data-reduction routine, the total uncertainty of the measuring process at each calibration point can be determined with high accuracy

Dissipation in vibrating superleak second sound transducers

International Nuclear Information System (INIS)

Giordano, N.

1985-01-01

We have performed an experimental study of the generation and detection of second sound in 4 He using vibrating superleak second sound transducers. At temperatures well below T/sub lambda/ and for low driving amplitudes, the magnitude of the generated second sound wave is proportional to the drive amplitude. However, near T/sub lambda/ and for high drive amplitudes this is no longer the case--instead, the second sound amplitude saturates. In this regime we also find that overtones of the drive frequency are generated. Our results suggest that this behavior is due to critical velocity effects in the pores of the superleak in the generator transducer. This type of measurement may prove to be a useful way in which to study critical velocity effects in confined geometries

Anxiolytic-like effect of inhalation of essential oil from Lavandula officinalis: investigation of changes in 5-HT turnover and involvement of olfactory stimulation.

Science.gov (United States)

Takahashi, Mizuho; Yamanaka, Ayako; Asanuma, Chihiro; Asano, Hiroko; Satou, Tadaaki; Koike, Kazuo

2014-07-01

Essential oil extracted from Lavandula officinalis (LvEO) has a long history of usage in anxiety alleviation with good evidence to support its use. However, findings and information regarding the exact pathway involved and mechanism of action remain inconclusive. Therefore, we aimed to (1) reveal the influence of olfactory stimulation, and (2) determine whether the serotonergic system is involved in the anxiolytic effect of LvEO when it is inhaled. To this end, we first compared the anxiety-related behaviors of normosmic and anosmic mice. LvEO inhalation caused notable elevation in anxiety-related parameters with or without olfactory perception, indicating that olfactory stimulation is not necessarily required for LvEO to be effective. Neurochemical analysis of the serotonin (5-HT) turnover rate, accompanied by EPM testing, was then performed. LvEO significantly increased the striatal and hippocampal levels of 5-HT and decreased turnover rates in accordance with the anxiolytic behavioral changes. These results, together with previous findings, support the hypothesis that serotonergic neurotransmission plays a certain role in the anxiolytic properties of LvEO.

Monitoring of composite structures using a network of integrated PVDF film transducers

International Nuclear Information System (INIS)

Guzmán, Enrique; Cugnoni, Joël; Gmür, Thomas

2015-01-01

Aiming to reduce costs, polyvinylidene difluoride (PVDF) film patches are an emerging alternative to more classic piezoelectric technologies, like ceramic patches, as transducers to measure local deformation in many structural applications. This choice is supported by advantages such as the low weight and mechanical flexibility of PVDF, making this polymer suitable for embedding inside full scale polymer based composite structures. Piezoelectric transducer patches can be used as actuators to dynamically excite full-scale composite structures, and as sensors to measure the strain. The main objective of this paper is to verify that the PVDF transducers can provide exploitable signals in the context of structural health monitoring. In order to do so, two aspects of the design of transducer network are investigated: the optimization of the sensor network, for which the effective independence method is proposed, and the use of operational modal analysis (OMA), since it is a simple method to extract the natural frequencies of a structure from a time series. The results of the analysis are compared to a reference set issued from experimental modal analysis (EMA), a simple, well-known, classic method, which is carried out using accelerometers and an impact hammer. By statistical means, it is shown that there is no significant difference between the two methods, and an optimized PVDF transducer network combined with OMA can perform the dynamic analysis of a structure as well as a classic EMA setup would do. This leads the way to the use of low-cost PVDF embedded transducer networks for robust composite material characterization. (paper)

Bulk Shear-Wave Transduction Experiments Using Magnetostrictive Transducers with a Thin Fe-Co Alloy Patch

Energy Technology Data Exchange (ETDEWEB)

Park, Jae Ha; Cho, Seung Hyun; Ahn, Bong Young; Kwon, Hyu Sang [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2010-08-15

Recently, the results of many studies have clarified the successful performance of magnetostrictive transducers in which a ferromagnetic patch is used for the transduction of guided shear waves; this is because a thin ferromagnetic patch with strong magnetostriction is very useful for generating and detecting shear wave. This investigation deals with bulk shear wave transduction by means of magnetostriction; on the other hand, the existing studies have been focused on guided shear waves. A modular transducer was developed: this transducer comprised a coil, magnets, and a thin ferromagnetic patch that was made of Fe-Co alloy. Some experiments were conducted to verify the performance of the developed transducer. Radiation directivity pattern of the developed transducer was obtained, and a test to detect the damage on a side drill hole of a steel block specimen was carried out. From the results of these tests, the good performance of the transducer for nondestructive testing was verified on the basis of the signal-to-noise ratio and narrow beam directivity.

Selection of Shear Horizontal Wave Transducers for Robotic Nondestructive Inspection in Harsh Environments

Directory of Open Access Journals (Sweden)

Sungho Choi

2016-12-01

Full Text Available Harsh environments and confined spaces require that nondestructive inspections be conducted with robotic systems. Ultrasonic guided waves are well suited for robotic systems because they can provide efficient volumetric coverage when inspecting for various types of damage, including cracks and corrosion. Shear horizontal guided waves are especially well suited for robotic inspection because they are sensitive to cracks oriented perpendicular or parallel to the wave propagation direction and can be generated with electromagnetic acoustic transducers (EMATs and magnetostrictive transducers (MSTs. Both types of transducers are investigated for crack detection in a stainless steel plate. The MSTs require the robot to apply a compressive normal force that creates frictional force coupling. However, the coupling is observed to be very dependent upon surface roughness and surface debris. The EMATs are coupled through the Lorentz force and are thus noncontact, although they depend on the lift off between transducer and substrate. After comparing advantages and disadvantages of each transducer for robotic inspection the EMATs are selected for application to canisters that store used nuclear fuel.

Multiple matching scheme for broadband 0.72Pb(Mg(13)Nb(23))O(3)-0.28PbTiO(3) single crystal phased-array transducer.

Science.gov (United States)

Lau, S T; Li, H; Wong, K S; Zhou, Q F; Zhou, D; Li, Y C; Luo, H S; Shung, K K; Dai, J Y

2009-05-01

Lead magnesium niobate-lead titanate single crystal 0.72Pb(Mg(13)Nb(23))O(3)-0.28PbTiO(3) (abbreviated as PMN-PT) was used to fabricate high performance ultrasonic phased-array transducer as it exhibited excellent piezoelectric properties. In this paper, we focus on the design and fabrication of a low-loss and wide-band transducer for medical imaging applications. A KLM model based simulation software PiezoCAD was used for acoustic design of the transducer including the front-face matching and backing. The calculated results show that the -6 dB transducer bandwidth can be improved significantly by using double lambda8 matching layers and hard backing. A 4.0 MHz PMN-PT transducer array (with 16 elements) was fabricated and tested in a pulse-echo arrangement. A -6 dB bandwidth of 110% and two-way insertion loss of -46.5 dB were achieved.

ACT listening test[Active transducers

Energy Technology Data Exchange (ETDEWEB)

Agerkvist, F. [Oersted, DTU, Kgs. Lyngby (Denmark); Fenger, L.M. [Bang and Olufsen ICEPower a/s, Kgs. Lyngby (Denmark)

2004-07-01

This report describes the series of subjective listening that was performed in order to test the subjective quality of the integration of amplifier and loudspeaker developed in the Active transducer project. The project is a fundamental study of the loss mechanisms in loudspeakers and amplifiers. The project has resulted in new switch mode amplifier topologies with very high audio performance at a very low cost. (BA)

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration

Directory of Open Access Journals (Sweden)

Xiaoyuan Wei

2017-09-01

Full Text Available Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

Three Transducer Ultrasonic Examination of Nuclear Fuel Rod Flush Welds At ENUSA

International Nuclear Information System (INIS)

Domingo, A.; Jimenez, J.M.

1998-01-01

From 1991 ENUSA are using UT microscope examination of flush weld with longitudinal wave (perpendicular to weld) looking for welding defects as porosity, weld thickness and penetration. In 1994 we included a new transducer off set placed, with shear waves to control cracks in welding. In 1997 we incorporated a new shear transducer, 30 degree centigrade angle, in order to control different orientation of cracks or Grain Boundary Separation (GBS) and to improve software capabilities. Then actual UT microscope equipment used to inspect rod welds consist, mainly in three transducer of 50 MHz mounted over a rotatory head. UT system is electronically synchronized and obtains 750 data points per revolution by transducer. A set of seven images of approx 100.000 data points is obtained for each weld. Thickness, pore size, pore depth, two of crack size and two of crack depth are presented and evaluated evaluated by the computer to obtain weld disposition. Resolution of 0,05 mm pore size is achieved by this equipment, thickness and penetration precision should be in the order of 0,005 mm and 0,05 mm respectively. Crack detection depend basically on its orientation, nevertheless position of transducer assures a high capability detection of cracks which should be formed at these welds. (Author)

Analysis and Implementation of Nonlinear Transducer Response over a Wider Response Range

Directory of Open Access Journals (Sweden)

Sheroz Khan

2008-03-01

Full Text Available In today’s automation systems transducers are making core elements in the instruments and the circuits used for measurement, control and industrial applications. The task of a transducer is to reproduce a physical quantity as an electrical signal which with the help of conditioning circuits, is transformed into a form that suits a corresponding ADC requirement before a digital equivalent output of the required physical quantity is produced. In the most ideal cases a digital quantity is a true replica of the physical quantity when the transducer has got a linear response. However, in most of the cases the transducers characteristics are nonlinear, and hence at very points along the whole range of the transducer characteristics, the corresponding digital output is an exact replica of the concerned physical parameter. This work is about how a physical read more accurately in the case of nonlinear sensor characteristics, and then a microcontroller is programmed with the same technique while reading from an input over the entire range. The data of the microcontroller reading shows very closely matched with the actual sensors response. Further, the reading error is considerably reduced to within 10 % of the actual physical which shows the utility of the technique in very sensitive applications.

Influence of Ultrasonic Nonlinear Propagation on Hydrophone Calibration Using Two-Transducer Reciprocity Method

Science.gov (United States)

Yoshioka, Masahiro; Sato, Sojun; Kikuchi, Tsuneo; Matsuda, Yoichi

2006-05-01

In this study, the influence of ultrasonic nonlinear propagation on hydrophone calibration by the two-transducer reciprocity method is investigated quantitatively using the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. It is proposed that the correction for the diffraction and attenuation of ultrasonic waves used in two-transducer reciprocity calibration can be derived using the KZK equation to remove the influence of nonlinear propagation. The validity of the correction is confirmed by comparing the sensitivities calibrated by the two-transducer reciprocity method and laser interferometry.

Inertia coupling analysis of a self-decoupled wheel force transducer under multi-axis acceleration fields.

Directory of Open Access Journals (Sweden)

Lihang Feng

Full Text Available Wheel force transducer (WFT, which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.

Inertia coupling analysis of a self-decoupled wheel force transducer under multi-axis acceleration fields.

Science.gov (United States)

Feng, Lihang; Lin, Guoyu; Zhang, Weigong; Dai, Dong

2015-01-01

Wheel force transducer (WFT), which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.

A 32 x 32 capacitive micromachined ultrasonic transducer array manufactured in standard CMOS.

Science.gov (United States)

Lemmerhirt, David F; Cheng, Xiaoyang; White, Robert; Rich, Collin A; Zhang, Man; Fowlkes, J Brian; Kripfgans, Oliver D

2012-07-01

As ultrasound imagers become increasingly portable and lower cost, breakthroughs in transducer technology will be needed to provide high-resolution, real-time 3-D imaging while maintaining the affordability needed for portable systems. This paper presents a 32 x 32 ultrasound array prototype, manufactured using a CMUT-in-CMOS approach whereby ultrasonic transducer elements and readout circuits are integrated on a single chip using a standard integrated circuit manufacturing process in a commercial CMOS foundry. Only blanket wet-etch and sealing steps are added to complete the MEMS devices after the CMOS process. This process typically yields better than 99% working elements per array, with less than ±1.5 dB variation in receive sensitivity among the 1024 individually addressable elements. The CMUT pulseecho frequency response is typically centered at 2.1 MHz with a -6 dB fractional bandwidth of 60%, and elements are arranged on a 250 μm hexagonal grid (less than half-wavelength pitch). Multiplexers and CMOS buffers within the array are used to make on-chip routing manageable, reduce the number of physical output leads, and drive the transducer cable. The array has been interfaced to a commercial imager as well as a set of custom transmit and receive electronics, and volumetric images of nylon fishing line targets have been produced.

Development of a novel omnidirectional magnetostrictive transducer for plate applications

Science.gov (United States)

Vinogradov, Sergey; Cobb, Adam; Bartlett, Jonathan; Udagawa, Youichi

2018-04-01

The application of guided waves for the testing of plate-type structures has been recently investigated by a number of research groups due to the ability of guided waves to detect corrosion in remote and hidden areas. Guided wave sensors for plate applications can be either directed (i.e., the waves propagate in a single direction) or omnidirectional. Each type has certain advantages and disadvantages. Omnidirectional sensors can inspect large areas from a single location, but it is challenging to define where a feature is located. Conversely, directed sensors can be used to precisely locate an indication, but have no sensitivity to flaws away from the wave propagation direction. This work describes a newly developed sensor that combines the strengths of both sensor types to create a novel omnidirectional transducer. The sensor transduction is based on a custom magnetostrictive transducer (MsT). In this new probe design, a directed, plate-application MsT with known characteristics was incorporated into an automated scanner. This scanner rotates the directed MsT for data collection at regular intervals. Coupling of the transducer to the plate is accomplished using a shear wave couplant. The array of data that is received is used for compiling B-scans and imaging, utilizing a synthetic aperture focusing algorithm (SAFT). The performance of the probe was evaluated on a 0.5-inch thick carbon steel plate mockup with a surface area of over 100 square feet. The mockup had a variety of known anomalies representing localized and distributed pitting corrosion, gradual wall thinning, and notches of different depths. Experimental data was also acquired using the new probe on a retired storage tank with known corrosion damage. The performance of the new sensor and its limitations are discussed together with general directions in technology development.

Energetic balance in an ultrasonic reactor using focused or flat high frequency transducers.

Science.gov (United States)

Hallez, L; Touyeras, F; Hihn, J Y; Klima, J

2007-09-01

In order to undertake irradiation of polymer blocks or films by ultrasound, this paper deals with the measurements of ultrasonic power and its distribution within the cell by several methods. The electric power measured at the transducer input is compared to the ultrasonic power input to the cell evaluated by calorimetry and radiation force measurement for different generator settings. Results obtained in the specific case of new transducer types (composites and focused composites i.e., HIFU: high intensity focused ultrasound) provide an opportunity to conduct a discussion about measurement methods. It has thus been confirmed that these measurement techniques can be applied to HIFU transducers. For all cases, results underlined the fact that measurement of radiation pressure for power evaluation is more adapted to low powers (generator-transducer-liquid and sample.

Development of ultrasonic testing equipment incorporating electromagnetic acoustic transducer

International Nuclear Information System (INIS)

Sato, Michio; Kimura, Motohiko; Okano, Hideharu; Miyazawa, Tatsuo; Nagase, Koichi; Ishikawa, Masaaki

1989-01-01

An ultrasonic testing equipment for use in in-service inspection of nuclear power plant piping has been developed, which comprises an angle-beam electromagnetic acoustic transducer mounted on a vehicle for scanning the piping surface to be inspected. The transducer functions without direct contact with the piping surface through couplant, and the vehicle does not require a guide track installed on the piping surface, being equipped with magnetic wheels that adhere to the piping material, permitting it to travel along the circumferential weld joint of a carbon steel pipe. The equipment thus dispenses with the laborious manual work involved in preparing the piping for inspection, such as removal of protective coating, surface polishing and installation of guide track and thereby considerably reduces the duration of inspection. The functioning principle and structural features of the transducer and vehicle are described, together with the results of trial operation of a prototype unit, which proved a 1mm deep notch cut on a test piece of 25mm thick carbon steel plate to be locatable with an accuracy of ±2mm. (author)

Structural model of standard ultrasonic transducer array developed for FEM analysis of mechanical crosstalk.

Science.gov (United States)

Celmer, M; Opieliński, K J; Dopierała, M

2018-02-01

One of the reasons of distortions in ultrasonic imaging are crosstalk effects. They can be divided into groups according to the way of their formation. One of them is constituted by mechanical crosstalk, which is propagated by a construction of a multi-element array of piezoelectric transducers. When an individual transducer is excited, mechanical vibrations are transferred to adjacent construction components, thereby stimulating neighboring transducers to an undesired operation. In order to explore ways of the propagation of such vibrations, the authors developed the FEM model of the array of piezoelectric transducers designed for calculations in COMSOL Multiphysics software. Simulations of activating individual transducers and calculated electrical voltages appearing on transducers unstimulated intentionally, were performed in the time domain in order to assess the propagation velocity of different vibration modes through the construction elements. On this basis, conclusions were drawn in terms of the participation of various construction parts of the array of piezoelectric transducers in the process of creating the mechanical crosstalk. The elaborated FEM model allowed also to examine the ways aimed at reducing the transmission of mechanical crosstalk vibrations through the components of the array. Studies showed that correct cuts in the fasteners and the front layer improve the reduction of the mechanical crosstalk effect. The model can become a helpful tool in the process of design and modifications of manufactured ultrasonic arrays particularly in terms of mechanical crosstalk reduction. Copyright © 2017 Elsevier B.V. All rights reserved.

The copying power of one-state tree transducers

DEFF Research Database (Denmark)

Engelfriet, Joost; Skyum, Sven

1982-01-01

One-state deterministic top-down tree transducers (or, tree homomorphisms) cannot handle “prime copying,” i.e., their class of output (string) languages is not closed under the operation L → {$(w$)f(n) short parallel w ε L, f(n) greater-or-equal, slanted 1}, where f is any integer function whose...... range contains numbers with arbitrarily large prime factors (such as a polynomial). The exact amount of nonclosure under these copying operations is established for several classes of input (tree) languages. These results are relevant to the extended definable (or, restricted parallel level) languages......, to the syntax-directed translation of context-free languages, and to the tree transducer hierarchy....

Modeling transducer impulse responses for predicting calibrated pressure pulses with the ultrasound simulation program Field II

DEFF Research Database (Denmark)

Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

2010-01-01

FIELD II is a simulation software capable of predicting the field pressure in front of transducers having any complicated geometry. A calibrated prediction with this program is, however, dependent on an exact voltage-to-surface acceleration impulse response of the transducer. Such impulse response...... is not calculated by FIELD II. This work investigates the usability of combining a one-dimensional multilayer transducer modeling principle with the FIELD II software. Multilayer here refers to a transducer composed of several material layers. Measurements of pressure and current from Pz27 piezoceramic disks...... transducer model and the FIELD II software in combination give good agreement with measurements....

Effect of stimuli, transducers and gender on acoustic change complex

Directory of Open Access Journals (Sweden)

Hemanth N. Shetty

2012-08-01

Full Text Available The objective of this study was to investigate the effect of stimuli, transducers and gender on the latency and amplitude of acoustic change complex (ACC. ACC is a multiple overlapping P1-N1-P2 complex reflecting acoustic changes across the entire stimulus. Fifteen males and 15 females, in the age range of 18 to 25 (mean=21.67 years, having normal hearing participated in the study. The ACC was recorded using the vertical montage. The naturally produced stimuli /sa/ and /si/ were presented through the insert earphone/loud speaker to record the ACC. The ACC obtained from different stimuli presented through different transducers from male/female participants were analyzed using mixed analysis of variance. Dependent t-test and independent t-test were performed when indicated. There was a significant difference in latency of 2N1 at the transition, with latency for /sa/ being earlier; but not at the onset portions of ACC. There was no significant difference in amplitude of ACC between the stimuli. Among the transducers, there was no significant difference in latency and amplitude of ACC, for both /sa/ and /si/ stimuli. Female participants showed earlier latency for 2N1 and larger amplitude of N1 and 2P2 than male participants, which was significant. ACC provides important insight in detecting the subtle spectral changes in each stimulus. Among the transducers, no difference in ACC was noted as the spectra of stimuli delivered were within the frequency response of the transducers. The earlier 2N1 latency and larger N1 and 2P2 amplitudes noticed in female participants could be due to smaller head circumference. The findings of this study will be useful in determining the capacity of the auditory pathway in detecting subtle spectral changes in the stimulus at the level of the auditory cortex.

Impact of biogenic nanoscale metals Fe, Cu, Zn and Se on reproductive LV chickens

International Nuclear Information System (INIS)

Nguyen, Quy Khiem; Nguyen, Van Kien; Nguyen, Khac Thinh; Nguyen, Duy Dieu; Nguyen, Hoai Chau; Tran, Xuan Tin; Nguyen, Huu Cuong; Phung, Duc Tien

2015-01-01

Using biogenic nanoscale metals (Fe, Cu, ZnO, Se) to supplement into diet premix of reproductive LV (a Vietnamese Luong Phuong chicken breed) chickens resulted in certain improvement of poultry farming. The experimental data obtained showed that the farming indices depend mainly on the quantity of nanocrystalline metals which replaced the inorganic mineral component in the feed premix. All four experimental groups with different quantities of the replacement nano component grew and developed normally with livability reaching 91 to 94%, hen’s bodyweight at 38 weeks of age and egg weight ranged from 2.53–2.60 kg/hen and 50.86–51.55 g/egg, respectively. All these farming indices together with laying rate, egg productivity and chick hatchability peaked at group 5 with 25% of nanoscale metals compared to the standard inorganic mineral supplement, while feed consumption was lowest. The results also confirmed that nanocrystalline metals Fe, Cu, ZnO and Se supplemented to chicken feed were able to decrease inorganic minerals in the diet premixes at least four times, allowing animals to more effectively absorb feed minerals, consequently decreasing environmental pollution risks. (paper)

Dissimilar trend of nonlinearity in ultrasound transducers and systems at resonance and non-resonance frequencies

DEFF Research Database (Denmark)

Ghasemi, Negareh; Zare, Firuz; Davari, Pooya

2017-01-01

Several factors can affect performance of an ultrasound system such as quality of excitation signal and ultrasound transducer behaviour. Nonlinearity of piezoelectric ultrasound transducers is a key determinant in designing a proper driving power supply. Although, the nonlinearity of piezoelectric...... was excited at different frequencies. Different excitation signals were generated using a linear power amplifier and a multilevel converter within a range of 30–200 V. Empirical relation was developed to express the resistance of the piezoelectric transducer as a nonlinear function of both excitation voltage...... and resonance frequency. The impedance measurements revealed that at higher voltage ranges, the piezoelectric transducer can be easily saturated. Also, it was shown that for the developed ultrasound system composed of two transducers (one transmitter and one receiver), the output voltage measured across...

Development of a Modular Magnetostrictive Transducer for Torsional Guided Wave Transduction in a Cylindrical Structure

Energy Technology Data Exchange (ETDEWEB)

Cho, Seung Hyun; Park, Jae Ha; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2009-10-15

Cylindrical structures such as pipes and shafts are widely used in various industrial facilities. Recently, researches on magnetostrictive transduction of torsional waves have been actively reported for the nondestructive evaluation of those cylindrical structures. However, the existing magnetostrictive patch transducer has somewhat inconvenient and time. Consuming process like patch bonding to a structure since it should employ a magnetostrictive patch having strong magnetostriction. To overcome these limitations of the existing transducer, in this work, we develop a novel modular magnetostrictive transducer to generate and measure torsional waves to inspect a cylindrical structure. The proposed transducer can be applied as viscous liquid coupling with shear couplant or dry coupling without coupling media instead of patch bonding to a structure. We describe a detailed structure of the modular transducer and conduct some experiments to verify its performance

Development of a Modular Magnetostrictive Transducer for Torsional Guided Wave Transduction in a Cylindrical Structure

International Nuclear Information System (INIS)

Cho, Seung Hyun; Park, Jae Ha; Kwon, Hyu Sang; Ahn, Bong Young; Lee, Seung Seok

2009-01-01

Cylindrical structures such as pipes and shafts are widely used in various industrial facilities. Recently, researches on magnetostrictive transduction of torsional waves have been actively reported for the nondestructive evaluation of those cylindrical structures. However, the existing magnetostrictive patch transducer has somewhat inconvenient and time. Consuming process like patch bonding to a structure since it should employ a magnetostrictive patch having strong magnetostriction. To overcome these limitations of the existing transducer, in this work, we develop a novel modular magnetostrictive transducer to generate and measure torsional waves to inspect a cylindrical structure. The proposed transducer can be applied as viscous liquid coupling with shear couplant or dry coupling without coupling media instead of patch bonding to a structure. We describe a detailed structure of the modular transducer and conduct some experiments to verify its performance

Toxoplasma gondii, Dirofilaria immitis, feline immunodeficiency virus (FIV), and feline leukemia virus (FeLV) infections in stray and pet cats (Felis catus) in northwest China: co-infections and risk factors.

Science.gov (United States)

Cong, Wei; Meng, Qing-Feng; Blaga, Radu; Villena, Isabelle; Zhu, Xing-Quan; Qian, Ai-Dong

2016-01-01

This study was conducted to estimate the prevalence of Toxoplasma gondii, Dirofilaria immitis, feline immunodeficiency virus (FIV), and feline leukemia virus (FeLV) infections among stray and pet cats in Lanzhou, northwest China, and to identify the influence of age, gender, and regions on seropositivity. T. gondii antibodies were examined in cat sera by the modified agglutination test (MAT). The circulating antigens of D. immitis and FeLV and specific antibodies to FIV were examined using kits commercially available. The overall prevalence of T. gondii, FIV, FeLV, and D. immitis was 19.34, 9.12, 11.33, and 3.04 %, respectively. For the genetic characterization of T. gondii genotypes in cats, genomic DNA was extracted from the seropositive cats and the T. gondii B1 gene was amplified using a semi-nested PCR. DNA samples giving positive B1 amplification were then genotyped using multilocus PCR-RFLP. Two T. gondii genotypes (ToxoDB#9 and ToxoDB#1) were identified. Results of the multivariate logistic regression analysis showed that older cats are more likely to be seropositive than juveniles for T. gondii, FIV, FeLV, and D. immitis. This is the first report of T. gondii genotypes in cats in northwest China. Moreover, the present study is the first study of retrovirus and D. immitis seroprevalence in cats in China. The results revealed that T. gondii, FIV, and FeLV infections are common in stray and pet cats in northwest China.

Development of an SH Wave Magnetostrictive Transducer Module for Guided Wave Testing of Plate Structures

International Nuclear Information System (INIS)

Cho, Seung Hyun; Park, Jae Ha; Kwon Hyu Sang; Ahn, Bong Young; Lee, Seung Seok

2009-01-01

Recently much attention has been paid to a guided wave due to its effective applicability to long range and fast inspection of structures. In guided wave based NDE, the appropriate selection of wave modes is one of important factors since the test performance is highly dependent on which mode of guided waves is employed. As far as plate-like structures are concerned, so far, SH guided wave has not been frequently applied compared to Lamb waves, which is mostly caused by the lack of proper and convenient transducers to generate and measure the SH waves. In this investigation, a new small-sized SH guided wave transducer based on magnetostriction is proposed. The present transducer was designed to be modular and be used with shear couplant to avoid the inconvenience of the existing magnetostrictive patch transducers, which comprises the ferromagnetic patch tightly bonded to a structure. The wave transduction mechanism and the detailed configuration of the present transducer are presented. Experimental verification is also conducted on test specimens and the results confirm the good performance of the present transducer module

Development of an SH Wave Magnetostrictive Transducer Module for Guided Wave Testing of Plate Structures

Energy Technology Data Exchange (ETDEWEB)

Cho, Seung Hyun; Park, Jae Ha; Kwon Hyu Sang; Ahn, Bong Young; Lee, Seung Seok [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2009-04-15

Recently much attention has been paid to a guided wave due to its effective applicability to long range and fast inspection of structures. In guided wave based NDE, the appropriate selection of wave modes is one of important factors since the test performance is highly dependent on which mode of guided waves is employed. As far as plate-like structures are concerned, so far, SH guided wave has not been frequently applied compared to Lamb waves, which is mostly caused by the lack of proper and convenient transducers to generate and measure the SH waves. In this investigation, a new small-sized SH guided wave transducer based on magnetostriction is proposed. The present transducer was designed to be modular and be used with shear couplant to avoid the inconvenience of the existing magnetostrictive patch transducers, which comprises the ferromagnetic patch tightly bonded to a structure. The wave transduction mechanism and the detailed configuration of the present transducer are presented. Experimental verification is also conducted on test specimens and the results confirm the good performance of the present transducer module

Ultrasonic non-destructive testing of pieces of complex geometry with a flexible phased array transducer

Science.gov (United States)

Chatillon; Cattiaux; Serre; Roy

2000-03-01

Ultrasonic non-destructive testing of components of complex geometry in the nuclear industry faces several difficulties: sensitivity variations due to unmatched contact, inaccurate localization of defects due to variations of transducer orientation, and uncovered area of the component. To improve the performances of such testing and defect characterization, we propose a new concept of ultrasonic contact phased array transducer. The phased array transducer has a flexible radiating surface able to fit the actual surface of the piece to optimize the contact and thus the sensitivity of the test. To control the transmitted field, and therefore to improve the defect characterization, a delay law optimizing algorithm is developed. To assess the capability of such a transducer, the Champ-Sons model, developed at the French Atomic Energy Commission for predicting field radiated by arbitrary transducers into pieces, has to be extended to sources directly in contact with pieces of complex geometry. The good behavior of this new type of probe predicted by computations is experimentally validated with a jointed transducer positioned on pieces of various profiles.

Piezoelectric transducer array microspeaker

KAUST Repository

Carreno, Armando Arpys Arevalo

2016-12-19

In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

Primate-specific microRNA-637 inhibits tumorigenesis in hepatocellular carcinoma by disrupting signal transducer and activator of transcription 3 signaling.

Science.gov (United States)

Zhang, Jin-fang; He, Ming-liang; Fu, Wei-ming; Wang, Hua; Chen, Lian-zhou; Zhu, Xiao; Chen, Ying; Xie, Dan; Lai, Paul; Chen, Gong; Lu, Gang; Lin, Marie C M; Kung, Hsiang-fu

2011-12-01

MiR-637 (microRNA-637) is a primate-specific miRNA belonging to the small noncoding RNA family, which represses gene regulation at the post-transcriptional expression level. Although it was discovered approximately 5 years ago, its biomedical significance and regulatory mechanism remain obscure. Our preliminary data showed that miR-637 was significantly suppressed in four HCC cell lines and, also, in most of the hepatocellular carcinoma (HCC) specimens, thereby suggesting that miR-637 would be a tumor suppressor in HCC. Simultaneously, the enforced overexpression of miR-637 dramatically inhibited cell growth and induced the apoptosis of HCC cells. The transcription factor, signal transducer and activator of transcription 3 (Stat3), is constitutively activated in multiple tumors, and aberrant Stat3 activation is linked to the promotion of growth and desensitization of apoptosis. Our study showed that Stat3 tyrosine 705 phosphorylation and several Stat3-regulated antiapoptotic genes were down-regulated in miR-637 mimics-transfected and Lv-miR637-infected HCC cells. In addition, miR-637 overexpression negatively regulated Stat3 phosphorylation by suppressing autocrine leukemia inhibitory factor (LIF) expression and exogenous LIF-triggered Stat3 activation and rescued cell growth in these cells. A nude mice model also demonstrated the above-described results, which were obtained from the cell model. Furthermore, we found that LIF was highly expressed in a large proportion of HCC specimens, and its expression was inversely associated with miR-637 expression. Our data indicate that miR-637 acted as a tumor suppressor in HCC, and the suppressive effect was mediated, at least in part, by the disruption of Stat3 activation. Copyright © 2011 American Association for the Study of Liver Diseases.

Focused ultrasound transducer spatial peak intensity estimation: a comparison of methods

Science.gov (United States)

Civale, John; Rivens, Ian; Shaw, Adam; ter Haar, Gail

2018-03-01

Characterisation of the spatial peak intensity at the focus of high intensity focused ultrasound transducers is difficult because of the risk of damage to hydrophone sensors at the high focal pressures generated. Hill et al (1994 Ultrasound Med. Biol. 20 259-69) provided a simple equation for estimating spatial-peak intensity for solid spherical bowl transducers using measured acoustic power and focal beamwidth. This paper demonstrates theoretically and experimentally that this expression is only strictly valid for spherical bowl transducers without a central (imaging) aperture. A hole in the centre of the transducer results in over-estimation of the peak intensity. Improved strategies for determining focal peak intensity from a measurement of total acoustic power are proposed. Four methods are compared: (i) a solid spherical bowl approximation (after Hill et al 1994 Ultrasound Med. Biol. 20 259-69), (ii) a numerical method derived from theory, (iii) a method using measured sidelobe to focal peak pressure ratio, and (iv) a method for measuring the focal power fraction (FPF) experimentally. Spatial-peak intensities were estimated for 8 transducers at three drive powers levels: low (approximately 1 W), moderate (~10 W) and high (20-70 W). The calculated intensities were compared with those derived from focal peak pressure measurements made using a calibrated hydrophone. The FPF measurement method was found to provide focal peak intensity estimates that agreed most closely (within 15%) with the hydrophone measurements, followed by the pressure ratio method (within 20%). The numerical method was found to consistently over-estimate focal peak intensity (+40% on average), however, for transducers with a central hole it was more accurate than using the solid bowl assumption (+70% over-estimation). In conclusion, the ability to make use of an automated beam plotting system, and a hydrophone with good spatial resolution, greatly facilitates characterisation of the FPF, and

Study of a Modified Displacement Transducer of a Piston in a Power Cylinder

Directory of Open Access Journals (Sweden)

S. C. BERA

2011-05-01

Full Text Available The position monitoring of the piston inside a power cylinder is very important in process plant measurement and control. In the present paper a modified inductance type position sensing technique of a power cylinder piston has been described. A modified inductance measuring transducer circuit has been designed to measure the change of inductance of a very high inductance coil. The theoretical equations of the proposed inductive sensor and the displacement transducer have been derived. The transducer has been experimentally tested and the experimental data are presented in the paper.

Effect of planecta and ROSE? on the frequency characteristics of blood pressure-transducer kits

OpenAIRE

Fujiwara, Shigeki; Kawakubo, Yoshifumi; Mori, Satoshi; Tachihara, Keiichi; Toyoguchi, Izumi; Yokoyama, Takeshi

2014-01-01

Pressure-transducer kits have frequency characteristics such as natural frequency and damping coefficient, which affect the monitoring accuracy. The aim of the present study was to investigate the effect of planecta ports and a damping device (ROSE?, Argon Medical Devices, TX, USA) on the frequency characteristics of pressure-transducer kits. The FloTrac sensor kit (Edwards Lifesciences, CA, USA) and the DTXplus transducer kit (Argon Medical Devices) were prepared with planecta ports, and the...

Genetic diversity in the feline leukemia virus gag gene.

Science.gov (United States)

Kawamura, Maki; Watanabe, Shinya; Odahara, Yuka; Nakagawa, So; Endo, Yasuyuki; Tsujimoto, Hajime; Nishigaki, Kazuo

2015-06-02

Feline leukemia virus (FeLV) belongs to the Gammaretrovirus genus and is horizontally transmitted among cats. FeLV is known to undergo recombination with endogenous retroviruses already present in the host during FeLV-subgroup A infection. Such recombinant FeLVs, designated FeLV-subgroup B or FeLV-subgroup D, can be generated by transduced endogenous retroviral env sequences encoding the viral envelope. These recombinant viruses have biologically distinct properties and may mediate different disease outcomes. The generation of such recombinant viruses resulted in structural diversity of the FeLV particle and genetic diversity of the virus itself. FeLV env diversity through mutation and recombination has been studied, while gag diversity and its possible effects are less well understood. In this study, we investigated recombination events in the gag genes of FeLVs isolated from naturally infected cats and reference isolates. Recombination and phylogenetic analyses indicated that the gag genes often contain endogenous FeLV sequences and were occasionally replaced by entire endogenous FeLV gag genes. Phylogenetic reconstructions of FeLV gag sequences allowed for classification into three distinct clusters, similar to those previously established for the env gene. Analysis of the recombination junctions in FeLV gag indicated that these variants have similar recombination patterns within the same genotypes, indicating that the recombinant viruses were horizontally transmitted among cats. It remains to be investigated whether the recombinant sequences affect the molecular mechanism of FeLV transmission. These findings extend our understanding of gammaretrovirus evolutionary patterns in the field. Copyright © 2015 Elsevier B.V. All rights reserved.

W-Band Circularly Polarized TE11 Mode Transducer

Science.gov (United States)