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Sample records for active npc converter

  1. The efficiency of three-level Active NPC converter for different PWM strategies

    Floricau, D.; Gateau, G.; Leredde, A.;

    2009-01-01

    biggest total losses. Different modulation functions have been elaborated to calculate conduction losses. These are characteristic for each device depending on the structure's type and on the control strategy. Using these functions medium and effective values of conduction currents have been calculated......The efficiency of power conversion is an important factor to design static converters. The paper is focused on the calculus of total losses of 3L-NPC and 3L-Active-NPC converters for different PWM strategies. The calculus was made in the most critical operating points when certain switches have the...

  2. A New PWM Strategy for Grid-Connected Half-Bridge Active NPC Converters With Losses Distribution Balancing Mechanism

    Lin, Ma; Kerekes, Tamas; Rodriguez, Pedro;

    2015-01-01

    Photovoltaic systems technological development is driven by the request for higher efficiency and safety. These concerns influence also the choice of the power converter stage. Several topologies have been proposed and many of them are available commercially. Among them, the neutral point clamped...... (NPC) and derived topologies offers high efficiency, low leakage current, and low EMI. However, one main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which leads to an unequal distribution of temperature that can affect lifetime. By...... using the active NPC (ANPC) topology, where the clamping diodes are replaced by bidirectional switches, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper, two known strategies are discussed and a new PWM...

  3. Open-switch fault detection method of an NPC converter for wind turbine systems

    Lee, June-Seok; Lee, Kyo-Beum; Blaabjerg, Frede

    2013-01-01

    In wind turbine generation (WTG) systems, the neutral-point-clamped (NPC) topology is widely used as the part of a back-to-back converter since the three-level NPC topology has more advantages than the conventional two-level inverter especially for high power. There are twelve switches in the NPC...

  4. Optimized Pulse Width Modulation for transformerless active-NPC inverters

    Achilladelis, Nikolaos; Koutroulis, Eftichios; Blaabjerg, Frede

    2014-01-01

    The transformerless DC/AC inverter topologies are employed in Photovoltaic systems in order to improve the power conversion efficiency, power density and cost. The Active-Neutral Point Clamped (Active-NPC) transformerless inverters have the advantage of achieving better thermal balance among their...... power semiconductors. In this paper, a new modulation technique is proposed for optimally controlling the power switches employed in transformerless Active-NPC inverters. The design results demonstrate that compared to the existing PWM strategies, using the proposed method results in lower total power...... losses and significantly better distribution of the power losses among the semiconductors of the Active-NPC inverter....

  5. Optimal design of NPC and Active-NPC transformerless PV inverters

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    Targeting at a cost-effective deployment of grid-connected PhotoVoltaic (PV) systems, this paper presents a new methodology for the optimal design of transformerless PV inverters, which are based on the Neutral Point Clamped (NPC) and the Active-Neutral Point Clamped (ANPC) topologies. The design...... optimal design methodology enables to maximize the economic benefit obtained during the lifetime period of the installed PV system....

  6. Open-Switch Fault Detection Method of a Back-to-Back Converter Using NPC Topology for Wind Turbine Systems

    Lee, June-Seok; Lee, Kyo_Beum; Blaabjerg, Frede

    2015-01-01

    In wind turbine generation (WTG) systems, a back-to-back converter with a neutral-point-clamped (NPC) topology is widely used because this topology has more advantages than a conventional two-level topology, particularly when operating at high power. There are 12 switches in the NPC topology. An...

  7. A SVPWM based on fluctuate capacitor voltage in 3L-NPC back-to-back converter applied to wind energy

    Chen, Quan; Wang, Qunjing; Chen, Zhe;

    2014-01-01

    between the fluctuate voltage of upper and lower capacitors is extracted. Based on this error factor the duty-time of every active voltage vector is calculated. In order to validate the model and the control strategy proposed in this paper, a 2MW 3L-NPC converter used in wind energy has been simulated.......' voltage, will cause variations of the voltage vector and the dwell time distribution in the synthesizing algorithm. In this paper a novel space vector PWM (SVPWM) for back-to-back 3L-NPC converter when unbalanced neutral point potential occurring is proposed. An error factor based on the difference...

  8. Development of modulation strategies for NPC converter addressing DC link voltage balancing and CMV reduction

    Boian, D.; Biris, C.; Teodorescu, Remus;

    2012-01-01

    3L-NPC inverters are more popular due to their superior performance compared with two level inverters. One of the most optimal applications for multilevel inverter is the Adjustable Speed Drives (ASD). The industry reported numerous ASD failures due to high frequency PWM. Those failures consist i...... strategies is to reduce the Common Mode Voltage (CMV) and balance the DC Link Voltage....

  9. The Impact of Power Switching Devices on the Thermal Performance of a 10 MW Wind Power NPC Converter

    Ma, Ke; Blaabjerg, Frede

    2012-01-01

    of significant deviation in the packaging structure, electrical characteristics, as well as thermal impedance, these available power switching devices may have various thermal cycling behaviors, which will lead to converter solutions with very different cost, size and reliability performance. As a result......, this paper aimed to investigate the thermal related characteristics of some important power switching devices. Their impact on the thermal cycling of a 10 MW three-level Neutral-Point-Clamped wind power converter is then evaluated under various operating conditions; the main focus will be on the grid...... connected inverter. It is concluded that the thermal performances of the 3L-NPC wind power converter can be significantly changed by the power device technology as well as their parallel configurations....

  10. The PWM strategies of grid-connected distributed generation active NPC inverters

    Ma, Lin; Xinmin, Jin; Kerekes, Tamas;

    2009-01-01

    leads to an unequal distribution of temperature. By using the Active NPC topology, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper two known strategies are discussed and a new proposed PWM strategy......, namely the Adjustable Losses Distribution (ALD) PWM strategy is proposed for better losses distribution in the Active NPC (ANPC) topology. Simulations using Simulink and the PLECS toolbox have been done for evaluating efficiency of different NPC topologies and some experimental results are presented in......The Neutral Point Clamped topology due to high efficiency, low leakage current and EMI, its integration is widely used in the distributed generation (DG) systems. However the main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which...

  11. The Impact of Power Switching Devices on the Thermal Performance of a 10 MW Wind Power NPC Converter

    Ke Ma

    2012-07-01

    Full Text Available Power semiconductor switching devices play an important role in the performance of high power wind energy generation systems. The state-of-the-art device choices in the wind power application as reported in the industry include IGBT modules, IGBT press-pack and IGCT press-pack. Because of significant deviation in the packaging structure, electrical characteristics, as well as thermal impedance, these available power switching devices may have various thermal cycling behaviors, which will lead to converter solutions with very different cost, size and reliability performance. As a result, this paper aimed to investigate the thermal related characteristics of some important power switching devices. Their impact on the thermal cycling of a 10 MW three-level Neutral-Point-Clamped wind power converter is then evaluated under various operating conditions; the main focus will be on the grid connected inverter. It is concluded that the thermal performances of the 3L-NPC wind power converter can be significantly changed by the power device technology as well as their parallel configurations.

  12. Multiple low frequency dual reference PWM control of a grid connected photovoltaic three phase NPC inverter with DC/DC boost converter

    Mechouma Rabiaa

    2014-01-01

    Full Text Available In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC inverter with DC/DC boost converter for constant and variable solar radiation.

  13. NPC Snapshots

    2008-01-01

    1.GRAND EVENT:Wu Bangguo,Chairman of the Standing Committee of the 11th National People’s Congress(NPC),delivers a work report during the annual session in the Great Hall of the People in Beijing on March 8 2.MEETTHE PRESS:Chong Yanmin,an NPC Deputy from Hunnan Province,the worst- hit area in the country’s recent snowstorms, talks to Beijing Review reporter about ways to minimize the effects of natural disasters

  14. Power density investigations for the large wind turbines' grid-side press-pack IGBT 3L-NPC-VSCs

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig;

    2012-01-01

    -thermal models are required to be derived, implemented, and utilized. In this study, employed as a grid-side medium voltage full-scale voltage source converters (VSCs) in a multi-MW wind turbine, press-pack IGBT three-level neutral-point-clamped VSC (3L-NPC-VSC), 3L active NPC-VSC (3L-ANPC-VSC), and 3L neutral...

  15. Analyze and Improve Lifetime in 3L-NPC Inverter from Power Cycle and Thermal Balance

    Chen, Quan; Chen, Zhe; Wang, Qunjing;

    2014-01-01

    load voltage is applied to reduce power cycle and switching losses. And then, three-level active neutral point-clamped topology is taken into account to wake the most thermo stressed device. In order to validate the improve lifetime method in this paper, a 2MW 3L-NPC converter used in wind energy has......Three-level Neutral-point-clamped (3L-NPC) topology is becoming a realistic alternative to the conventional one in high-voltage and high-power application. Studies show that the power cycling mean time to failure (MTTF) of the semiconductor bond wire in 3L-NPC inverter system may be very short...

  16. Power Capability Investigation Based on Electrothermal Models of Press-pack IGBT Three-Level NPC and ANPC VSCs for Multimegawatt Wind Turbines

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig;

    2012-01-01

    addressed in this study for the three-level neutral-point-clamped voltage source converter (3L-NPC-VSC) and 3L Active NPC VSC (3L-ANPC-VSC) with press-pack insulated gate bipolar transistors employed as a grid-side converter. In order to investigate these VSCs' power capabilities under various operating...... conditions with respect to these limiting factors, a power capability generation algorithm based on the converter electrothermal model is developed. Built considering the VSCs' operation principles and physical structure, the model is validated by a 2 MV·A single-phase 3L-ANPC-VSC test setup. The power...

  17. Angiotensin Converting Enzyme Activity in Alopecia Areata

    Mohammad Reza Namazi; Armaghan Ashraf; Farhad Handjani; Ebrahim Eftekhar; Amir Kalafi

    2014-01-01

    Background. Alopecia areata (AA) is a chronic inflammatory disease of the hair follicle. The exact pathogenesis of AA remains unknown, although recent studies support a T-cell mediated autoimmune process. On the other hand, some studies have proposed that the renin-angiotensin-aldosterone system (RAAS) may play a role in autoimmunity. Therefore, we assessed serum activity of angiotensin converting enzyme (ACE), a component of this system, in AA. Methods. ACE activity was measured in the sera ...

  18. New active load voltage clamp for HF-link converters

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper proposes a new active clamp for HF-link converters, which features very high efficiency by returning the clamped energy back to the primary side through a small auxiliary converter. It also increases the reliability of HF-link converters by providing an alternative load current path...

  19. Changes of Plasma Angiotensin-Converting Enzyme Activity during Hemodialysis *

    Koo, Wan Suh; Lee, Yong Joon; Kim, Hye Su; Kim, Suk Young; Choi, Euy Jin; Chang, Yoon Sik; Yoon, Young Suk; Bang, Byung Kee

    1987-01-01

    Plasma angiotensin-converting enzyme activity was measured by spectrophotometer in normal subjects and in patients with end stage renal failure, serially during a routine hemodialysis. Patients on maintenance hemodialysis tended to be associated with elevated plasma angiotensin-converting enzyme activity versus normal subjects. Plasma angiotensin-converting enzyme activity was significantly elevated in patients with chronic renal failure after 5 hours of hemodialysis(p

  20. Analysis of a Multilevel Dual Active Bridge (ML-DAB DC-DC Converter Using Symmetric Modulation

    M. A. Moonem

    2015-04-01

    Full Text Available Dual active bridge (DAB converters have been popular in high voltage, low and medium power DC-DC applications, as well as an intermediate high frequency link in solid state transformers. In this paper, a multilevel DAB (ML-DAB has been proposed in which two active bridges produce two-level (2L-5L, 5L-2L and 3L-5L voltage waveforms across the high frequency transformer. The proposed ML-DAB has the advantage of being used in high step-up/down converters, which deal with higher voltages, as compared to conventional two-level DABs. A three-level neutral point diode clamped (NPC topology has been used in the high voltage bridge, which enables the semiconductor switches to be operated within a higher voltage range without the need for cascaded bridges or multiple two-level DAB converters. A symmetric modulation scheme, based on the least number of angular parameters rather than the duty-ratio, has been proposed for a different combination of bridge voltages. This ML-DAB is also suitable for maximum power point tracking (MPPT control in photovoltaic applications. Steady-state analysis of the converter with symmetric phase-shift modulation is presented and verified using simulation and hardware experiments.

  1. New active load voltage clamp for HF-link converters

    Ljusev, P.; Andersen, M.A.E.

    2005-07-01

    This paper proposes a new active clamp for HF-link converters, which features very high efficiency by returning the clamped energy back to the primary side through a small auxiliary converter. It also increases the reliability of HF-link converters by providing an alternative load current path during malfunctions of the secondary bidirectional bridge. The feasibility of the approach is shown on audio power amplifier prototype. New integrated magnetics design is presented that incorporates both the main power and auxiliary transformer on the same magnetic core. (au)

  2. Effects of prednisolone on angiotensin converting enzyme activity.

    Roulston, J. E.; O'Malley, G I; Douglas, J G

    1984-01-01

    Plasma angiotensin converting enzyme was measured in 23 asthmatic subjects before and after administration of prednisolone, 20 mg daily, for seven days. Plasma specimens from seven patients with asthma, seven with sarcoidosis and 14 normal subjects were also assayed before and after the addition of prednisolone in vitro. A plasma free extract of normal lung was also prepared and assayed before and after prednisolone treatment. Mean angiotensin converting enzyme activity was significantly grea...

  3. NPC Deputies-Facts and Figures

    2008-01-01

    With the opening of the First Session of the 11th National People’s Congress (NPC),China’s top legislature, the newly elected deputies to the 11th NPC have begun performing their duties. The 2,987 new deputies were elected from 34 of China’s regions and the People’s Liberation Army.The com- position of the new deputies changes greatly when compared with the 10th NPC,indicating that the country’s top legislature is giving the grassroots more seats.

  4. Shunt Active and Series Active Filters-Based Power Quality Conditioner for Matrix Converter

    P. Jeno Paul

    2011-01-01

    Full Text Available This paper proposes a series active filter and shunt active filter to minimize the power quality impact present in matrix converters instead of passive filter. A matrix converter produces significant harmonics and nonstandard frequency components into load. The proposed system compensates the sag and swell problems efficiently in matrix converter. The proposed system has been tested and validated on the matrix converter using MATLAB/Simulink software. Simulated results confirm that the active power filters can maintain high performance for matrix converter.

  5. A Single Residue in Ebola Virus Receptor NPC1 Influences Cellular Host Range in Reptiles.

    Ndungo, Esther; Herbert, Andrew S; Raaben, Matthijs; Obernosterer, Gregor; Biswas, Rohan; Miller, Emily Happy; Wirchnianski, Ariel S; Carette, Jan E; Brummelkamp, Thijn R; Whelan, Sean P; Dye, John M; Chandran, Kartik

    2016-01-01

    Filoviruses are the causative agents of an increasing number of disease outbreaks in human populations, including the current unprecedented Ebola virus disease (EVD) outbreak in western Africa. One obstacle to controlling these epidemics is our poor understanding of the host range of filoviruses and their natural reservoirs. Here, we investigated the role of the intracellular filovirus receptor, Niemann-Pick C1 (NPC1) as a molecular determinant of Ebola virus (EBOV) host range at the cellular level. Whereas human cells can be infected by EBOV, a cell line derived from a Russell's viper (Daboia russellii) (VH-2) is resistant to infection in an NPC1-dependent manner. We found that VH-2 cells are resistant to EBOV infection because the Russell's viper NPC1 ortholog bound poorly to the EBOV spike glycoprotein (GP). Analysis of panels of viper-human NPC1 chimeras and point mutants allowed us to identify a single amino acid residue in NPC1, at position 503, that bidirectionally influenced both its binding to EBOV GP and its viral receptor activity in cells. Significantly, this single residue change perturbed neither NPC1's endosomal localization nor its housekeeping role in cellular cholesterol trafficking. Together with other recent work, these findings identify sequences in NPC1 that are important for viral receptor activity by virtue of their direct interaction with EBOV GP and suggest that they may influence filovirus host range in nature. Broader surveys of NPC1 orthologs from vertebrates may delineate additional sequence polymorphisms in this gene that control susceptibility to filovirus infection. IMPORTANCE Identifying cellular factors that determine susceptibility to infection can help us understand how Ebola virus is transmitted. We asked if the EBOV receptor Niemann-Pick C1 (NPC1) could explain why reptiles are resistant to EBOV infection. We demonstrate that cells derived from the Russell's viper are not susceptible to infection because EBOV cannot bind to

  6. A Single Residue in Ebola Virus Receptor NPC1 Influences Cellular Host Range in Reptiles

    Ndungo, Esther; Herbert, Andrew S.; Raaben, Matthijs; Obernosterer, Gregor; Biswas, Rohan; Miller, Emily Happy; Wirchnianski, Ariel S.; Carette, Jan E.; Brummelkamp, Thijn R.; Whelan, Sean P.

    2016-01-01

    ABSTRACT Filoviruses are the causative agents of an increasing number of disease outbreaks in human populations, including the current unprecedented Ebola virus disease (EVD) outbreak in western Africa. One obstacle to controlling these epidemics is our poor understanding of the host range of filoviruses and their natural reservoirs. Here, we investigated the role of the intracellular filovirus receptor, Niemann-Pick C1 (NPC1) as a molecular determinant of Ebola virus (EBOV) host range at the cellular level. Whereas human cells can be infected by EBOV, a cell line derived from a Russell’s viper (Daboia russellii) (VH-2) is resistant to infection in an NPC1-dependent manner. We found that VH-2 cells are resistant to EBOV infection because the Russell’s viper NPC1 ortholog bound poorly to the EBOV spike glycoprotein (GP). Analysis of panels of viper-human NPC1 chimeras and point mutants allowed us to identify a single amino acid residue in NPC1, at position 503, that bidirectionally influenced both its binding to EBOV GP and its viral receptor activity in cells. Significantly, this single residue change perturbed neither NPC1’s endosomal localization nor its housekeeping role in cellular cholesterol trafficking. Together with other recent work, these findings identify sequences in NPC1 that are important for viral receptor activity by virtue of their direct interaction with EBOV GP and suggest that they may influence filovirus host range in nature. Broader surveys of NPC1 orthologs from vertebrates may delineate additional sequence polymorphisms in this gene that control susceptibility to filovirus infection. IMPORTANCE Identifying cellular factors that determine susceptibility to infection can help us understand how Ebola virus is transmitted. We asked if the EBOV receptor Niemann-Pick C1 (NPC1) could explain why reptiles are resistant to EBOV infection. We demonstrate that cells derived from the Russell’s viper are not susceptible to infection because EBOV

  7. Active Power Filter: Review of Converter Topologies and Control Strategies

    SARIBULUT, Lütfü; Ahmet TEKE; MERAL, M. EMIN; Tumay, Mehmet

    2011-01-01

    Decrease in the cost of power electronic devices and improvement in the efficiency of both power converters and energy storage components have increased the applicability of new technological solutions such as Custom Power (CP) and Flexible AC Transmission Systems (FACTS) Devices. Active Power Filter (APF) is one of the CP devices and can mitigate harmonics, reactive power and unbalanced load currents originating from load side. In this study, a comprehensive review of APF studies, the advant...

  8. Silica Exposure and Serum Angiotensin Converting Enzyme Activity

    YK Sharma; AB Karnik; RR Tiwari

    2010-01-01

    Background: Silicosis is known in industrial workers for centuries. Till recently, the mainstay of its diagnosis and progress was clinical examination of the respiratory system, pulmonary function test and chest radiography. Several biomarkers such as serum angiotensin converting enzyme (ACE) activity have been examined to determine the extent of silicosis. Objective: To elucidate the effect of age, gender, duration of exposure to silica dust, smoking habit, and pulmonary function status on t...

  9. Procedure to convert mean and low activity radioactive wastes

    A procedure to convert mean and low activity radioactive effluents into a suitable solid is described. Radioactive compounds are precipitated in this procedure in which 0.6 to 2 parts (by weight) of cement are mixed with 0.5 to 5% (by weight) of asbestos (relative to the cement) together with the necessary quantity of water for the cement to set, and in addition, with 5 to 30% (by weight) of bitumen (relative to the cement)

  10. Lung angiotensin converting enzyme activity in chronically hypoxic rats.

    Kay, J M; Keane, P. M.; Suyama, K L; Gauthier, D.

    1985-01-01

    A study was carried out to test the hypothesis that the reduced lung angiotensin converting enzyme (ACE) activity which occurs in chronic hypoxia is related to the development of pulmonary hypertension rather than to hypoxia per se. Right ventricular mean systolic pressure (Prvs, mm Hg) and ACE activity (nmol/mg protein/min) in lung tissue homogenates were measured in seven groups of four rats placed in a hypobaric chamber (380 mm Hg; 51 kPa) for two to 24 days. Identical measurements were ma...

  11. Lung angiotensin converting enzyme activity in rats with pulmonary hypertension.

    Keane, P. M.; Kay, J M; Suyama, K L; Gauthier, D.; Andrew, K

    1982-01-01

    We have studied serum and lung tissue angiotensin converting enzyme (ACE) activity in female Wistar rats with pulmonary hypertension induced by two different methods. Chronic pulmonary hypertension was produced in one group of 10 rats (CH) by confinement in a hypobaric chamber (380 mmHg) for three weeks, and in another group fo 10 rats (M) by a single subcutaneous injection of monocrotaline (60 mg/kg body weight). In these two groups of tests rats and in 20 untreated controls (C), we evaluate...

  12. Regulation of Sterol Transport between Membranes and NPC2†

    Xu, Zhi; Farver, William; Kodukula, Sarala; Storch, Judith

    2008-01-01

    Niemann-Pick disease type C (NPC) is caused by defects in either the NPC1 or NPC2 gene and is characterized by accumulation of cholesterol and glycolipids in the late endosome/lysosome compartment. NPC2 is an intralysosomal protein that binds cholesterol in vitro. Previous studies demonstrated rapid rates of cholesterol transfer from NPC2 to model membranes [Cheruku, S. R., et al. (2006) J. Biol. Chem. 281, 31594–31604]. To model the potential role of NPC2 as a lysosomal cholesterol export pr...

  13. Trace element profiles in the hair of nasopharyngeal carcinoma (NPC) patients

    The trace element profiles of the scalp hair of NPC patients, aged between 30 and 69, were measured using neutron activation analysis and compared with those of normal healthy people within the same age bracket. The washing method of using detergent and washing powder was found to be comparable to that of using ether. Difference in the mean concentration of each element in the two groups was tested by Student's t-test. A significantly lower value of strontium (Sr) and significantly higher values of arsenic (As), iron (Fe) and vanadium (V)were found in the hair of NPC patients. The relative values of As and Fe found were consistent with the results of other findings on NPC patients, using different measuring methods. The V content in the hair of NPC patients was three times that of healthy people. (author). 19 refs., 2 tabs

  14. LMP-1 and Nasopharyngeal Carcinoma (NPC

    Anggun Indah Budiningrum

    2014-06-01

    Conclusions:LMP-1 has strongest interaction with H2O2 than nicotine and nitrosamine. This is predicted that H2O2 is external factor that affect LMP-1 switching to lytic infection in NPC patients. [Cukurova Med J 2014; 39(3.000: 480-487

  15. Cascaded impedance networks for NPC inverter

    Li, Ding; Gao, Feng; Loh, Poh Chiang;

    2010-01-01

    Multilevel inverters are getting more and more attracted because they have better output waveform quality and lower semiconductor voltage stress. The Z-source NPC is a kind of single stage multilevel inverter which has the ability of voltage boost. But the boost capability is relatively low when ...

  16. Olfactory deficits in Niemann-Pick type C1 (NPC1 disease.

    Marina Hovakimyan

    Full Text Available BACKGROUND: Niemann-Pick type C disease (NPC is a rare autosomal recessive lipid storage disease characterized by progressive neurodegeneration. As only a few studies have been conducted on the impact of NPC on sensory systems, we used a mutant mouse model (NPC1(-/- to examine the effects of this disorder to morphologically distinct regions of the olfactory system, namely the olfactory epithelium (OE and olfactory bulb (OB. METHODOLOGY/PRINCIPAL FINDINGS: For structural and functional analysis immunohistochemistry, electron microscopy, western blotting, and electrophysiology have been applied. For histochemistry and western blotting, we used antibodies against a series of neuronal and glia marker proteins, as well as macrophage markers. NPC1(-/- animals present myelin-like lysosomal deposits in virtually all types of cells of the peripheral and central olfactory system. Especially supporting cells of the OE and central glia cells are affected, resulting in pronounced astrocytosis and microgliosis in the OB and other olfactory cortices. Up-regulation of Galectin-3, Cathepsin D and GFAP in the cortical layers of the OB underlines the critical role and location of the OB as a possible entrance gate for noxious substances. Unmyelinated olfactory afferents of the lamina propria seem less affected than ensheathing cells. Supporting the structural findings, electro-olfactometry of the olfactory mucosa suggests that NPC1(-/- animals exhibit olfactory and trigeminal deficits. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a pronounced neurodegeneration and glia activation in the olfactory system of NPC1(-/-, which is accompanied by sensory deficits.

  17. Standing wave tube electro active polymer wave energy converter

    Jean, Philippe; Wattez, Ambroise; Ardoise, Guillaume; Melis, C.; Van Kessel, R.; Fourmon, A.; Barrabino, E.; Heemskerk, J.; Queau, J. P.

    2012-04-01

    Over the past 4 years SBM has developed a revolutionary Wave Energy Converter (WEC): the S3. Floating under the ocean surface, the S3 amplifies pressure waves similarly to a Ruben's tube. Only made of elastomers, the system is entirely flexible, environmentally friendly and silent. Thanks to a multimodal resonant behavior, the S3 is capable of efficiently harvesting wave energy from a wide range of wave periods, naturally smoothing the irregularities of ocean wave amplitudes and periods. In the S3 system, Electro Active Polymer (EAP) generators are distributed along an elastomeric tube over several wave lengths, they convert wave induced deformations directly into electricity. The output is high voltage multiphase Direct Current with low ripple. Unlike other conventional WECs, the S3 requires no maintenance of moving parts. The conception and operating principle will eventually lead to a reduction of both CAPEX and OPEX. By integrating EAP generators into a small scale S3, SBM achieved a world first: direct conversion of wave energy in electricity with a moored flexible submerged EAP WEC in a wave tank test. Through an extensive testing program on large scale EAP generators, SBM identified challenges in scaling up to a utility grid device. French Government supports the consortium consisting of SBM, IFREMER and ECN in their efforts to deploy a full scale prototype at the SEMREV test center in France at the horizon 2014-2015. SBM will be seeking strategic as well as financial partners to unleash the true potentials of the S3 Standing Wave Tube Electro Active Polymer WEC.

  18. Active Clamped ZVS Forward Converter With Soft-Switched Synchronous Rectifier

    AÇIK, Adnan; ÇADIRCI, Işık

    2002-01-01

    This paper presents the analysis, design and implementation of an active-clamped, ZVS forward converter equipped with a soft-switched synchronous rectifier (ACFC-SR) proposed for high-efficiency, low output voltage dc-dc converter applications. The converter efficiency is maximized due to the soft-switching of the main, active clamp, synchronous rectifier and freewheeling MOSFET switches. The operating principles of the ACFC-SR are analyzed in detail and the converter performance is ...

  19. Development of a high power NPC inverter

    It has been widely reported that the Common-Mode-Current disturbs a stable operation in various accelerator complex. The reason why we have such an undesired noise current is that, in an inverter circuit, the potential of neutral point will be fluctuated between high-voltage to ground-potential during each switching modes. In the Neutral-Point-Clamped (NPC) inverters, on the other hands, the neutral point of output terminals can be always clamped to the ground-potential if we chose a proper switching algorism. So that no voltage will be applied across the neutral-point and the ground potential. This is the reason why we have initiated a development of the NPC inverter to apply it into the accelerator complex. In an inverter circuit, undesirable surge voltage will be applied during its switching period. This surge voltage exceeds the maximum rating of an IGBT in worst case. Moreover, the surge voltage will increase the switching loss in devices. It is important to reduce this surge voltage to secure a stable operation of the inverter circuit. Details of our approach to minimize the surge voltage and the operational results of a developed NPC inverter are reviewed in this article. (author)

  20. A common mode-less power supply operation with NPC inverters

    It is widely known that common-mode current can reduce the performance of power converters or their load system. Especially for the high-precision power converters such as used for the magnets in accelerator, the common mode noise is very serious. For rejection of the common mode current, we propose to use NPC (Neutral Point Clumped) inverters with limited switching modes so that the common mode current is in principle not produced. In this article, we present the comparison between our proposal and other known methods and show the advantage to use the NPC inverters. In addition, we report the result of our experiment which is performed to show the validity of our proposal. (author)

  1. Angiotensin-Converting Enzyme Inhibitors and Active Tuberculosis

    Wu, Jiunn-Yih; Lee, Meng-Tse Gabriel; Lee, Si-Huei; Lee, Shih-Hao; Tsai, Yi-Wen; Hsu, Shou-Chien; Chang, Shy-Shin; Lee, Chien-Chang

    2016-01-01

    Abstract Numerous epidemiological data suggest that the use of angiotensin-converting enzyme inhibitors (ACEis) can improve the clinical outcomes of pneumonia. Tuberculosis (TB) is an airborne bacteria like pneumonia, and we aimed to find out whether the use of ACEis can decrease the risk of active TB. We conducted a nested case–control analysis by using a 1 million longitudinally followed cohort, from Taiwan national health insurance research database. The rate ratios (RRs) for TB were estimated by conditional logistic regression, and adjusted using a TB-specific disease risk score (DRS) with 71 TB-related covariates. From January, 1997 to December, 2011, a total of 75,536 users of ACEis, and 7720 cases of new active TB were identified. Current use (DRS adjusted RR, 0.87 [95% CI, 0.78–0.97]), but not recent and past use of ACEis, was associated with a decrease in risk of active TB. Interestingly, it was found that chronic use (>90 days) of ACEis was associated with a further decrease in the risk of TB (aRR, 0.74, [95% CI, 0.66–0.83]). There was also a duration response effect, correlating decrease in TB risk with longer duration of ACEis use. The decrease in TB risk was also consistent across all patient subgroups (age, sex, heart failure, cerebrovascular diseases, myocardial infraction, renal diseases, and diabetes) and patients receiving other cardiovascular medicine. In this large population-based study, we found that subjects with recent and chronic use of ACEis were associated with decrease in TB risk. PMID:27175655

  2. Src mediates the mechanical activation of myogenesis by activating TNFα-converting enzyme

    Niu, Airu; Wen, Yefei; Liu, Huijie; Zhan, Mei; Jin, Bingwen; Li, Yi-Ping

    2013-01-01

    Mechanical stimulation affects many biological aspects in living cells through mechanotransduction. In myogenic precursor cells (MPCs), mechanical stimulation activates p38 mitogen-activated protein kinase (MAPK), a key regulator of myogenesis, via activating TNFα-converting enzyme (TACE, also known as ADAM17), to release autocrine TNFα. However, the signaling mechanism of mechanical activation of TACE is unknown. Because TACE possesses the structural features of substrates of the non-recepto...

  3. Advanced glycation end products induce fibrogenic activity in NASH by modulating the TNFα converting enzyme activity

    Joy, Jiang X; Chen, Xiangling; Fukada, Hiroo; Serizawa, Nobuko; Devaraj, Sridevi; Török, Natalie J.

    2013-01-01

    Advanced glycation end products (AGEs) accumulate in patients with diabetes, yet the link between AGEs and the inflammatory and fibrogenic activity in non-alcoholic steatohepatitis (NASH) has not been explored. TNFα converting enzyme (TACE) is at the center of inflammatory processes. As the main natural regulator of TACE activity is the tissue inhibitor of metalloproteinase 3 (Timp3), we hypothesized that AGEs induce TACE through NADPH oxidase 2 (NOX2); and the downregulation of Sirtuin 1 (Si...

  4. Inhibition of Angiotensin-Converting Enzyme Activity by Flavonoids: Structure-Activity Relationship Studies

    Ligia Guerrero; Julián Castillo; Mar Quiñones; Santiago Garcia-Vallvé; Lluis Arola; Gerard Pujadas; Begoña Muguerza

    2012-01-01

    Previous studies have demonstrated that certain flavonoids can have an inhibitory effect on angiotensin-converting enzyme (ACE) activity, which plays a key role in the regulation of arterial blood pressure. In the present study, 17 flavonoids belonging to five structural subtypes were evaluated in vitro for their ability to inhibit ACE in order to establish the structural basis of their bioactivity. The ACE inhibitory (ACEI) activity of these 17 flavonoids was determined by fluorimetric metho...

  5. The Circuit-Level Decoupling Modulation Strategy for Three-Level Neutral-Point-Clamped (TL-NPC) Inverter

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2011-01-01

    In this paper, a circuit-level decoupling modulation strategy is proposed for the three-level (TL) neutral-point-clamped (NPC) inverters. With the proposed modulation scheme, the TL-NPC inverter can be decoupled into two three-level Buck converters in each defined operating section, which makes the...... controller design much simpler. The decoupling principle including the driving signal synthesis and the neutral point potential variation are analyzed detailed. It is found that switching losses can be reduced by one third and the voltage balance between the dividing dc link capacitors can be achieved...

  6. Carrier phase shifted SPWM based on current sourced multi-modular converter for active power filter

    王立乔; 李建林; 张仲超

    2004-01-01

    A novel current-source active power filter(APF)based on multi-modular converter with carrier phase-shifted SPWM(CPS-SPWM)technique is proposed.With this technique,the effect of equivalent high switching frequency converter is obtained with low switching frequency converter.It is very promising in current-source APF that adopt superconducting magnetic energy storage component.

  7. Endothelin converting enzyme (ECE) activity in human vascular smooth muscle

    Maguire, Janet J.; Johnson, Christopher M.; Mockridge, James W; Davenport, Anthony P

    1997-01-01

    We have characterized the human smooth muscle endothelin converting enzyme (ECE) present in the media of the endothelium-denuded human umbilical vein preparation.Endothelin-1 (ET-1) and ET-2 were potent constrictors of umbilical vein with EC50 values of 9.2 nM and 29.6 nM, respectively. ET-1 was at least 30 times more potent than ET-3 suggesting the presence of constrictor ETA receptors. Little or no response was obtained to the ETB-selective agonist sarafotoxin 6c. These data suggest that en...

  8. Local operators' role in NPC operation and their career development

    Operation staff is the key of generating electricity in the nuclear power plant. They make sure the safety and profit of NPC. Operation of NPC depends on shift staff and local operators help RO in MCR to handle the power production with facing the equipment directly. The following describes local operators how to play important roles in AP1000 unit operation. Meanwhile, their training and career development also are referred to. (authors)

  9. Pulmonary abnormalities in animal models due to Niemann-Pick type C1 (NPC1 or C2 (NPC2 disease.

    Blair R Roszell

    Full Text Available Niemann-Pick C (NPC disease is due to loss of NPC1 or NPC2 protein function that is required for unesterified cholesterol transport from the endosomal/lysosomal compartment. Though lung involvement is a recognized characteristic of Niemann-Pick type C disease, the pathological features are not well understood. We investigated components of the surfactant system in both NPC1 mutant mice and felines and in NPC2 mutant mice near the end of their expected life span. Histological analysis of the NPC mutant mice demonstrated thickened septae and foamy macrophages/leukocytes. At the level of electron microscopy, NPC1-mutant type II cells had uncharacteristically larger lamellar bodies (LB, mean area 2-fold larger, while NPC2-mutant cells had predominantly smaller lamellar bodies (mean area 50% of normal than wild type. Bronchoalveolar lavage from NPC1 and NPC2 mutant mice had an approx. 4-fold and 2.5-fold enrichment in phospholipid, respectively, and an approx. 9-fold and 35-fold enrichment in cholesterol, consistent with alveolar lipidosis. Phospholipid and cholesterol also were elevated in type II cell LBs and lung tissue while phospholipid degradation was reduced. Enrichment of surfactant protein-A in the lung and surfactant of the mutant mice was found. Immunocytochemical results showed that cholesterol accumulated in the LBs of the type II cells isolated from the affected mice. Alveolar macrophages from the NPC1 and NPC2 mutant mice were enlarged compared to those from wild type mice and were enriched in phospholipid and cholesterol. Pulmonary features of NPC1 mutant felines reflected the disease described in NPC1 mutant mice. Thus, with the exception of lamellar body size, the lung phenotype seen in the NPC1 and NPC2 mutant mice were similar. The lack of NPC1 and NPC2 proteins resulted in a disruption of the type II cell surfactant system contributing to pulmonary abnormalities.

  10. An active trap filter for high-power voltage source converters

    Bai, Haofeng; Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    This paper proposes a power electronic based device to actively trap the switching current ripples for highpower converters. Control principle and system design of the active trap filter are discussed first. Comparisons of the active trap filter with LCL and LLCL filters are then carried out in...

  11. High Efficiency Interleaved Active Clamped Dc-Dc Converter with Fuel Cell for High Voltage Applications

    Sona P

    2014-02-01

    Full Text Available A high efficiency interleaved ZVS active clamped current fed dc-dc converter is proposed in this paper specially used for fuel cell applications. As the fuel cell output is very low we are in need of a step up dc-dc converter. Here a current fed dc-dc converter is used. Two current fed dc-dc converters are interleaved by connecting their inputs in parallel and outputs in series. With this proposed methodology input current ripples in the fuel cell stacks can be reduced and a regulated output voltage ripples can be obtained. The active clamping circuit used in this model absorbs the turn off voltage spikes hence low voltage devices with low on state resistance can be used.Voltage doubler circuits will give double the output voltage than normal with smaller transformer turns ratio and flexibility. The proposed method is simulated in MATLAB for verifying the accuracy of the proposed design.

  12. A Color LED Driver Implemented by the Active Clamp Forward Converter

    C. H. Chang; Cheng, H L; C. A. Cheng; E. C. Chang

    2013-01-01

    Because light emitting diodes (LEDs) have the advantages of dc working voltage, high luminescent efficiency, shortignition time, high reliability and pollution free, they have substituted for incandescent bulbs and fluorescent lampsgradually. In order to simplify circuit complexity, an active clamp forward converter with the sequential color display(SCD) control is proposed to drive red, green and blue (RGB) LED arrays. The proposed converter has zero-voltageswitching (ZVS) operations of both...

  13. Structure of glycosylated NPC1 luminal domain C reveals insights into NPC2 and Ebola virus interactions.

    Zhao, Yuguang; Ren, Jingshan; Harlos, Karl; Stuart, David I

    2016-03-01

    Niemann-pick type C1 (NPC1) is an endo/lysosomal membrane protein involved in intracellular cholesterol trafficking, and its luminal domain C is an essential endosomal receptor for Ebola and Marburg viruses. We have determined the crystal structure of glycosylated NPC1 luminal domain C and find all seven possible sites are glycosylated. Mapping the disease mutations onto the glycosylated structure reveals a potential binding face for NPC2. Knowledge-based docking of NPC1 onto Ebola viral glycoprotein and sequence analysis of filovirus susceptible and refractory species reveals four critical residues, H418, Q421, F502 and F504, some or all of which are likely responsible for the species-specific susceptibility to the virus infection. PMID:26846330

  14. Hybrid Modulation of Bidirectional Three-Phase Dual-Active-Bridge DC Converters for Electric Vehicles

    Yen-Ching Wang

    2016-06-01

    Full Text Available Bidirectional power converters for electric vehicles (EVs have received much attention recently, due to either grid-supporting requirements or emergent power supplies. This paper proposes a hybrid modulation of the three-phase dual-active bridge (3ΦDAB converter for EV charging systems. The designed hybrid modulation allows the converter to switch its modulation between phase-shifted and trapezoidal modes to increase the conversion efficiency, even under light-load conditions. The mode transition is realized in a real-time manner according to the charging or discharging current. The operation principle of the converter is analyzed in different modes and thus design considerations of the modulation are derived. A lab-scaled prototype circuit with a 48V/20Ah LiFePO4 battery is established to validate the feasibility and effectiveness.

  15. Angiotensin-converting enzyme activity and cognitive impairment during hypoglycaemia in healthy humans

    Pedersen-Bjergaard, Ulrik; Thomsen, Carsten E; Høgenhaven, Hans;

    2008-01-01

    INTRODUCTION: In type 1 diabetes increased risk of severe hypoglycaemia is associated with high angiotensin-converting enzyme (ACE) activity. We tested in healthy humans the hypothesis that this association is explained by the reduced ability of subjects with high ACE activity to maintain normal...

  16. NPC 15669 blocks neutrophil CD18 increase and lung injury during cardiopulmonary bypass in pigs

    J. M. Bator

    1993-01-01

    Full Text Available During cardiopulmonary bypass (CPB, neutrophils become activated due to contact with extracorporeal surfaces and binding of complement fragments C3a and C5a, leading to extravasation and subsequent tissue damage. In this study, the effects of the leumedin NPC 15669 (N [9H - (2,7 dimethylfluorenyl - 9 - methoxy car bonyl]-L-leucine, a leukocyte recruitment inhibitor, were evaluated in a pig model of CPB. NPC 15669 caused significant inhibition of CPB associated increase in CD18 upregulation, lung tissue myeloperoxidase content, and percentage wet weight compared to controls. Lung histology revealed clear airways and minimal neutrophil infiltration in treated animals vs. significant oedema and cellular infiltration in controls. It is concluded that CPB causes a dramatic increase in neutrophil CD18, and that leumedins are effective in inhibiting neutrophil activation and subsequent tissue injury when administered during CPB.

  17. A Tapped-Inductor Buck-Boost Converter for a Dielectric ElectroActive Polymer Generator

    Dimopoulos, Emmanouil; Munk-Nielsen, Stig

    2014-01-01

    Energy harvesting applications based on Dielectric ElectroActive Polymer (DEAP) generators have been in the spotlight in recent years after the latter ones’ documented advantages against competing electromagnetic and field-activated technologies. Yet, the need for bidirectional energy flow under...... high step-up and high step-down voltage conversion ratios, accompanied by low-average but relatively high-peak currents, imposes great challenges on the design of the employed power electronic converter. In addition, the effective operational range of the converter is usually limited by the lack of...

  18. Miglustat Reverts the Impairment of Synaptic Plasticity in a Mouse Model of NPC Disease

    G. D’Arcangelo

    2016-01-01

    Full Text Available Niemann-Pick type C disease is an autosomal recessive storage disorder, characterized by abnormal sequestration of unesterified cholesterol within the late endolysosomal compartment of cells and accumulation of gangliosides and other sphingolipids. Progressive neurological deterioration and insurgence of symptoms like ataxia, seizure, and cognitive decline until severe dementia are pathognomonic features of the disease. Here, we studied synaptic plasticity phenomena and evaluated ERKs activation in the hippocampus of BALB/c NPC1−/− mice, a well described animal model of the disease. Our results demonstrated an impairment of both induction and maintenance of long term synaptic potentiation in NPC1−/− mouse slices, associated with the lack of ERKs phosphorylation. We then investigated the effects of Miglustat, a recent approved drug for the treatment of NPCD. We found that in vivo Miglustat administration in NPC1−/− mice was able to rescue synaptic plasticity deficits, to restore ERKs activation and to counteract hyperexcitability. Overall, these data indicate that Miglustat may be effective for treating the neurological deficits associated with NPCD, such as seizures and dementia.

  19. Miglustat Reverts the Impairment of Synaptic Plasticity in a Mouse Model of NPC Disease.

    D'Arcangelo, G; Grossi, D; Racaniello, M; Cardinale, A; Zaratti, A; Rufini, S; Cutarelli, A; Tancredi, V; Merlo, D; Frank, C

    2016-01-01

    Niemann-Pick type C disease is an autosomal recessive storage disorder, characterized by abnormal sequestration of unesterified cholesterol within the late endolysosomal compartment of cells and accumulation of gangliosides and other sphingolipids. Progressive neurological deterioration and insurgence of symptoms like ataxia, seizure, and cognitive decline until severe dementia are pathognomonic features of the disease. Here, we studied synaptic plasticity phenomena and evaluated ERKs activation in the hippocampus of BALB/c NPC1-/- mice, a well described animal model of the disease. Our results demonstrated an impairment of both induction and maintenance of long term synaptic potentiation in NPC1-/- mouse slices, associated with the lack of ERKs phosphorylation. We then investigated the effects of Miglustat, a recent approved drug for the treatment of NPCD. We found that in vivo Miglustat administration in NPC1-/- mice was able to rescue synaptic plasticity deficits, to restore ERKs activation and to counteract hyperexcitability. Overall, these data indicate that Miglustat may be effective for treating the neurological deficits associated with NPCD, such as seizures and dementia. PMID:26885401

  20. Effects of Mooring Systems on the Performance of a Wave Activated Body Energy Converter

    Zanuttigh, Barbara; Angelelli, Elisa; Kofoed, Jens Peter

    Aim of this paper is to analyse the power and hydraulic performance of a floating Wave Energy Converter with the purpose at optimising its design for installation in arrays. The paper presents new experiments carried out in 1:30 scale on a single device of the Wave Activated Body type in the deep-water...

  1. A new Zero Voltage Switching three-level NPC inverter

    He, Ning; Chen, Yenan; Xu, Dehong;

    2015-01-01

    A novel Zero Voltage Switching (ZVS) three-level NPC inverter topology using a new ZVS Space Vector Modulation (SVM) scheme is proposed. A detailed operation analysis of ZVS three-level NPC inverter is given. The ZVS condition of the proposed ZVS inverter is derived and it can be achieved of all...... switches in the proposed inverter, which include both the main switches and the auxiliary switches. The design of resonant circuits parameters is also provided. Finally the proposed circuit and ZVS SVM scheme are verified by experimental results and demonstrate a superior performance....

  2. A Color LED Driver Implemented by the Active Clamp Forward Converter

    C. H. Chang

    2013-03-01

    Full Text Available Because light emitting diodes (LEDs have the advantages of dc working voltage, high luminescent efficiency, shortignition time, high reliability and pollution free, they have substituted for incandescent bulbs and fluorescent lampsgradually. In order to simplify circuit complexity, an active clamp forward converter with the sequential color display(SCD control is proposed to drive red, green and blue (RGB LED arrays. The proposed converter has zero-voltageswitching (ZVS operations of both the main switch and the auxiliary switch, resulting in high system efficiency. DrivingRGB LED arrays sequentially by one converter can save components and reduce cost significantly. Additionally, thepulse-width modulation (PWM control is applied to achieve a large chromaticity variation. The circuit operations areanalyzed in detail and the circuit parameters are designed based on the practical considerations. Finally, an illustrativeexample is implemented to demonstrate the feasibility and validity of the proposed LED driver.

  3. Integrated Circuit of CMOS DC-DC Buck Converter with Differential Active Inductor

    Kaoutar Elbakkar

    2011-11-01

    Full Text Available In this paper, we propose a new design of DC-DC buck converter (BC, which the spiral inductor is replaced by a differential gyrator with capacitor load (gyrator-C implemented in 0.18um CMOS process. The gyrator-C transforms the capacitor load (which is the parasitic capacitor of MOSFETS to differential active inductor DAI. The low-Q value of DAI at switching frequency of converter (few hundred kHz is boosted by adding a negative impedance converter (NIC. The transistor parameters of DAI and NIC can be properly chosen to achieve the desirable value of equivalent inductance L (few tens H, and the maximum-Q value at the switching frequency, and thus the efficiency of converter is improved. Experimental results show that the converter supplied with an input voltage of 1V, provides an output voltage of 0.74V and output ripple voltage of 10mV at 155 kHz and Q-value is maximum (#8776;4226 at this frequency.

  4. Angiotensin I-Converting Enzyme Inhibitor Activity on Egg Albumen Fermentation

    Nahariah, N.; A M Legowo; Abustam, E.; Hintono, A.

    2015-01-01

    Lactobacillus plantarum is used for fermentation of fish products, meat and milk. However, the utilization of these bacteria in egg processing has not been done. This study was designed to evaluate the potential of fermented egg albumen as a functional food that is rich in angiotensin I-converting enzyme inhibitors activity (ACE-inhibitor activity) and is antihypertensive. A completely randomized design was used in this study with six durations of fermentation (6, 12, 18, 24, 30, and 36 h) as...

  5. Demonstration of extrapulmonary activity of angiotensin converting enzyme in intact tissue preparations.

    Lembeck, F.; Griesbacher, T; Eckhardt, M.

    1990-01-01

    1. The activity of angiotensin converting enzyme (ACE) has been studied on functional parameters of intact isolated preparations of extrapulmonary tissues. The conversion of angiotensin I (A I) to angiotensin II (A II) and the cleavage of bradykinin (BK) were used as indicators of ACE activity. Captopril was employed as a specific inhibitor of ACE. 2. Captopril augmented the BK-induced contractions of the rat isolated uterus, the BK- and substance P-induced contractions of the guinea-pig ileu...

  6. Superior decoupled control of active and reactive power for three-phase voltage source converters

    RAHBARIMAGHAM, HESAM; AMIRI, ERFAN MAALI; VAHIDI, Behrooz; GHAREHPETIAN, GEVORG BABAMALEK; Abedi, Mehrdad

    2015-01-01

    This paper presents an active-reactive power control strategy for voltage source converters (VSCs) based on derivation of the direct and quadrature components of the VSC output current. The proposed method utilizes a multivariable proportional-integral controller and provides almost completely decoupled control capability of the active and reactive power with almost full disturbance rejection due to step changes in the power exchanged between the VSC and the grid. It also imposes fast transie...

  7. Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC) patients

    Undifferentiated Nasopharyngeal Carcinoma (NPC) patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV) which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL) and tumor- infiltrating (TIL) lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10) and three immunoglobulin isotypes (IgM, IgG, IgA). Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM) for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA). Data were analysed using Student's t-test and probability values below 5% were considered significant. The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002), IL-10 (p = 0,020), IgM (p= 0,0003) and IgG (p < 0,0001) than their PBL. On the other hand, patients PBL produced significantly higher levels of IL-2 (p = 0,022), IL-10 (p = 0,016) and IgM (p = 0,004) than those of controls. No significant differences for IL-6 and IgA were observed. Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC

  8. Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC patients

    Bouzouita Kamel

    2004-09-01

    Full Text Available Abstract Background Undifferentiated Nasopharyngeal Carcinoma (NPC patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL and tumor- infiltrating (TIL lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10 and three immunoglobulin isotypes (IgM, IgG, IgA. Methods Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA. Data were analysed using Student's t-test and probability values below 5% were considered significant. Results The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002, IL-10 (p = 0,020, IgM (p= 0,0003 and IgG (p Conclusion Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC.

  9. Simulation Based Performance analysis of Active Clamp DHB ZVZCS Bidirectional DC-DC converter for Low Power Applications

    V.V.Subrahmanya Kumar Bhajana

    2012-06-01

    Full Text Available A novel active clamp dual half bridge DC/DC converter with bidirectional power flow is proposed in this paper and comparative analysis between active clamp DHB ZVZCS and ZVS-ZCS bidirectional DC-DC converter topologies is also presented. By adding active clamping circuits to both bridges, zero voltage and zero current switching are achieved to improve the performance of the bidirectional DC/DC converter. The principle of operation is analyzed and simulated. With the proposed active clamp ZVZCS concept, the MATLAB simulation results of the applications of the fuel cell and battery have been obtained and compared with those of ZVS-ZCS bidirectional converter. The simulation results of proposed converter is compared with the ZVS-ZCS bidirectional DC-DC converter, efficiency, switching losses are the key parameters compared.

  10. Effect of Jatropha curcas Peptide Fractions on the Angiotensin I-Converting Enzyme Inhibitory Activity

    Segura-Campos, Maira R.; Fanny Peralta-González; Arturo Castellanos-Ruelas; Chel-Guerrero, Luis A.; David A. Betancur-Ancona

    2013-01-01

    Hypertension is one of the most common worldwide diseases in humans. Angiotensin I-converting enzyme (ACE) plays an important role in regulating blood pressure and hypertension. An evaluation was done on the effect of Alcalase hydrolysis of defatted Jatropha curcas kernel meal on ACE inhibitory activity in the resulting hydrolysate and its purified fractions. Alcalase exhibited broad specificity and produced a protein hydrolysate with a 21.35% degree of hydrolysis and 34.87% ACE inhibition. U...

  11. Protein Kinase C Regulates the Cell Surface Activity of Endothelin-Converting Enzyme-1

    Smith, A Ian; Lew, Rebecca A.; Thomas, Walter G; Tochon-Danguy, Nathalie

    2006-01-01

    The potent vasoconstrictor endothelin is a 21 amino acid peptide whose principal physiological function is to regulate vascular tone. The generation of endothelin is crucially dependent on the local presence and activity of endothelin converting enzyme-1 (ECE-1) expressed on the surface of vascular endothelial cells. In this study, we have shown in endothelial cells that the enzyme is phosphorylated, and that phosphorylation is increased by phorbol ester stimulation of protein kinase C (PKC)....

  12. Angiotensin converting enzyme 2 (ACE2) activity in fetal calf serum: implications for cell culture research

    Lubel, J. S.; Herath, C. B.; Velkoska, E.; Casley, D. J.; Burrell, L. M.; Angus, P. W.

    2008-01-01

    Cell culture experiments often employ the use of culture media that contain fetal calf serum (FCS). The angiotensin peptides angiotensin II and angiotensin 1–7 have opposing effects with angiotensin converting enzyme 2 (ACE2) being the enzyme predominantly responsible for generating angiotensin 1–7 from angiotensin II. The effect of FCS on angiotensin peptides has not previously been described. We have shown that FCS has ACE2 enzyme activity capable of degrading angiotensin II and generating ...

  13. Single-stage active clamp power factor correction AC/DC converter

    2007-01-01

    A simple single-stage AC/DC converter circuit with active clamp is presented. The operation theory and state are analyzed. The experimental results show that the voltage across main switch can be clamped to a certain value, and zero voltage switching (ZVS) can be achieved. The voltage stress and switching loss are both decreased. In range of the whole load, power factors can be always more than 97%, and the highest efficiency can reach 88%.

  14. Robust Vehicle Suspension System by Converting Active & Passive Control of a Vehicle to Semi-Active Control System Analytically

    Hassan Elahi; Dr. Riffat Asim Pasha; Dr. Asif Israr; Dr. M. Zubair Khan

    2014-01-01

    In this research work a simplified translational model of an automotive suspension system is constructed by only considering the translation motion of one wheel of a car. Passive Vehicle Suspension System is converted into Semi Active Vehicle System. Major advantage achieved by this system is that it adjusts the damping of the suspension system without the application of any actuator by using MATLAB® simulations. The semi-active control is found to control the vibration of suspens...

  15. The employment of post graduates by NPC

    The Nuclear Power Company has the sole responsibility in Britain for the design, construction, and commissioning of nuclear power stations. The Company employs some 2400 people, mainly at its two principal administrative and laboratory sites at Risley, Cheshire and Whetstone, Leicester. In carrying out its responsibilities the Company utilises skills in design, project management, planning, quality control, research and development and many other facets of contemporary nuclear engineering. Accordingly it has well formed views on the employment and training of the engineer and scientists who must exhibit and manage such skills. These views are brought out in this paper with particular reference to the relevance of post graduate training to the Company's Research and Development Department. Staff with post graduate research experience are also employed on other engineering activities in the company. The relevance of their experience to non-research work they undertake is also discussed. (author)

  16. Predictive control of a direct series resonant converter with active output voltage compensation

    Reyes-Moraga, Eduardo Felipe

    2015-01-01

    Modern high power supplies are based on resonant converters in order to use high frequency reactive elements (for reduced size) without sacrificing converter efficiency. In an effort to achieve compact high power supplies, direct power converter topologies have been considered, since these are mainly characterised by their high power density. A direct resonant converter topology combines matrix converters with conventional resonant converters. This work focused on achieving high quality i...

  17. Proceedings of nuclear plant chemistry conference 2014 Sapporo (NPC 2014)

    The International Conference on Water Chemistry of Nuclear Reactor Systems (Nuclear Plant Chemistry Conference, NPC) focuses on the latest developments in the science and technology of water chemistry control in nuclear reactor systems (www.npc2014.net). The conference is a forum where engineers and scientists from universities, research institutes, and service organizations in cooperation with utility engineers address the challenges of water chemistry control and improvement of material integrity in future LWR operation. In 2014 the focus will be on increasing safety and reliability for LWRs as well as improving plant operation by presenting and discussing enhancements in water chemistry based on the latest R and D and operational experiences shared among its participants. This meeting will also provide lessons learned from Fukushima Daiichi NPP accident in March 2011 such as the latest information on FP chemistry, decontaminations, and so on. All the papers presented at the entitled meeting are indexed individually. (J.P.N.)

  18. Angiotensin-converting enzyme inhibitory activity of milk fermented by wild and industrial Lactococcus lactis strains.

    Rodríguez-Figueroa, J C; Reyes-Díaz, R; González-Córdova, A F; Troncoso-Rojas, R; Vargas-Arispuro, I; Vallejo-Cordoba, B

    2010-11-01

    Angiotensin I-converting enzyme inhibitory (ACEI) activity was evaluated and compared in milk fermented by wild and commercial starter culture Lactococcus lactis strains after 48 h of incubation. The highest ACEI activities were found in WSE from milk inoculated with wild L. lactis strains isolated from artisanal dairy products and commercial starter cultures. On the other hand, the lowest ACEI activities were found in WSE from milk inoculated with wild strains isolated from vegetables. Moreover, the IC(50) values (concentration that inhibits 50% activity) of WSE from artisanal dairy products were the lowest, indicating that these fractions were the most effective in inhibiting 50% of ACE activity. In fact, a strain isolated from artisanal cheese presented the lowest IC(50) (13 μg/mL). Thus, it appears that wild L. lactis strains isolated from artisanal dairy products and commercial starter cultures showed good potential for the production of fermented dairy products with ACEI properties. PMID:20965317

  19. A 10 kW dc-dc converter using IGBTs with active snubbers. [Insulated Gate Bipolar Transistor

    Masserant, Brian J.; Shriver, Jeffrey L.; Stuart, Thomas A.

    1993-01-01

    This full bridge dc-dc converter employs zero voltage switching (ZVS) on one leg and zero current switching (ZCS) on the other. This technique produces exceptionally low IGBT switching losses through the use of an active snubber that recycles energy back to the source. Experimental results are presented for a 10 kW, 20 kHz converter.

  20. Discontinuous PWM Modulation Strategy with Circuit-Level Decoupling Concept of Three-Level Neutral-Point Clamped (NPC) Inverter

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2013-01-01

    inverters, but also reduces the switching loss of the inverter along with an inherent neutral point (NP) voltage control. Based on a circuit-level decoupling concept, the NPC inverter can be decoupled into two three-level Buck converters in every defined operating section, and thereby the controller design...... can be reduced by one third. In order to explain the operation of this topology properly, the decoupling principle including the driving signal synthesis and the NP potential variation are analyzed in detail in this paper. Finally the viability and performance of the proposed modulation scheme...

  1. 2 MW Active Bouncer Converter Design for Long Pulse Klystron Modulators

    Aguglia, D

    2012-01-01

    This paper presents some design issues of a 2 MW interleaved buck converter which is used as an active bouncer droop compensator for a 5.5MW long pulse klystron modulator. This novel design concept presents many challenges in terms of voltage ripple versus pulse rise-time. Issues related to the voltage ripple specification versus output filter design are discussed in detail. The design study is analyzed analytically, simulated numerically and is validated by experimental results obtained from a full power prototype.

  2. Nandrolone increases angiotensin-I converting enzyme activity in rats tendons

    Rita de Cassia Marqueti

    2015-06-01

    Full Text Available INTRODUCTION: The renin-angiotensin system (RAS has been associated with several biological processes of the human body, regulating, among others blood pressure and water and electrolytes balance. Moreover, RAS also regulates connective tissue growth. Recently, studies have shown that the use of nandrolone modifies the angiotensin-I converting enzyme (ACE activity and increases collagen deposition in the heart. OBJECTIVE: The aim of study was to evaluate the Angiotensin-I converting enzyme (ACE activity in the superficial flexor tendon (SFT and in serum after load exercise in combination with anabolic androgenic steroid (AAS administration after training session and six weeks of detraining. METHODS: Forty-eight Wistar rats were used into two groups (G1 and G2 subdivided into four subgroups: Sedentary (S; trained (T; AAS-treated (Deca-Durabolin(r, 5mg/kg, twice a week sedentary rats (AAS and AAS-treated and trained animals (AAST. Trained groups performed jumps in water: four series of 10 jumps each, followed by a 30 sec interval between the series, for seven weeks. RESULTS: Training increased ACE activity in the SFT compared to the control group (p <0.05. Both AAS and AAST groups presented higher ACE activity levels (p < 0.05. The AAST increased the ACE activity only compared to the trained animals. Only the AAST group presented significant higher levels of ACE in the serum. In the G2 group, all experimental groups presented decreased ACE activity in the serum and in the tendon, as compared to the control group. CONCLUSION: This study indicates that AAS administration and its combination with exercise increased ACE activity of tendons. AAS abuse could compromise tendon adaptation causing maladaptive remodeling.

  3. CES1 genetic variation affects the activation of angiotensin-converting enzyme inhibitors.

    Wang, X; Wang, G; Shi, J; Aa, J; Comas, R; Liang, Y; Zhu, H-J

    2016-06-01

    The aim of the study was to determine the effect of carboxylesterase 1 (CES1) genetic variation on the activation of angiotensin-converting enzyme inhibitor (ACEI) prodrugs. In vitro incubation study of human liver, intestine and kidney s9 fractions demonstrated that the ACEI prodrugs enalapril, ramipril, perindopril, moexipril and fosinopril are selectively activated by CES1 in the liver. The impact of CES1/CES1VAR and CES1P1/CES1P1VAR genotypes and diplotypes on CES1 expression and activity on enalapril activation was investigated in 102 normal human liver samples. Neither the genotypes nor the diplotypes affected hepatic CES1 expression and activity. Moreover, among several CES1 nonsynonymous variants studied in transfected cell lines, the G143E (rs71647871) was a loss-of-function variant for the activation of all ACEIs tested. The CES1 activity on enalapril activation in human livers with the 143G/E genotype was approximately one-third of that carrying the 143G/G. Thus, some functional CES1 genetic variants (for example, G143E) may impair ACEI activation, and consequently affect therapeutic outcomes of ACEI prodrugs. PMID:26076923

  4. A High Step-Down Interleaved Buck Converter with Active-Clamp Circuits for Wind Turbines

    Chih-Lung Shen

    2012-12-01

    Full Text Available In this paper, a high step-down interleaved buck coupled-inductor converter (IBCC with active-clamp circuits for wind energy conversion has been studied. In high step-down voltage applications, an IBCC can extend duty ratio and reduce voltage stresses on active switches. In order to reduce switching losses of active switches to improve conversion efficiency, a IBCC with soft-switching techniques is usually required. Compared with passive-clamp circuits, the IBCC with active-clamp circuits have lower switching losses and minimum ringing voltage of the active switches. Thus, the proposed IBCC with active-clamp circuits for wind energy conversion can significantly increase conversion efficiency. Finally, a 240 W prototype of the proposed IBCC with active-clamp circuits was built and implemented. Experimental results have shown that efficiency can reach as high as 91%. The proposed IBCC with active-clamp circuits is presented in high step-down voltage applications to verify the performance and the feasibility for energy conversion of wind turbines.

  5. 3D-pelin NPC-hahmon animaatio

    Hautoniemi, Julianna

    2015-01-01

    Opinnäytetyön toimeksiantajana toimi GameHunger projects, joka on aloitteleva pelinkehittäjätiimi. Tiimillä on työn alla heidän ensimmäinen 3D-videopeli. Tavoitteena oli luoda yhdelle pelin lintumaisista NPC-hahmoista animaatiota erilaisia pelitilanteita varten. Hahmoanimaatio luotiin alusta loppuun 3ds Max -ohjelmalla. Animaatio-ohjelmistoa voidaan kuitenkin joutua vaihtamaan kesken pelinkehitysprosessin. Jatkokehityksen kannalta tavoitteena oli selvittää, kuinka 3ds Maxilla luotua anima...

  6. Using Averaged Modeling for Capacitors Voltages Observer in NPC Inverter

    Bassem Omri

    2012-01-01

    Full Text Available This paper developed an adaptive observer to estimate capacitors voltages of a three-level neutral-point-clamped (NPC inverter. A robust estimated method using one parameter is proposed, which eliminates the voltages sensors. An averaged modeling of the inverter was used to develop the observer. This kind of modeling allows a good trade-off between simulation cost and precision. Circuit model of the inverter (implemented in Simpower Matlab simulator associated to the observer algorithm was used to validate the proposed algorithm.

  7. Protein Kinase C Regulates the Cell Surface Activity of Endothelin-Converting Enzyme-1.

    Smith, A Ian; Lew, Rebecca A; Thomas, Walter G; Tochon-Danguy, Nathalie

    2006-09-01

    The potent vasoconstrictor endothelin is a 21 amino acid peptide whose principal physiological function is to regulate vascular tone. The generation of endothelin is crucially dependent on the local presence and activity of endothelin converting enzyme-1 (ECE-1) expressed on the surface of vascular endothelial cells. In this study, we have shown in endothelial cells that the enzyme is phosphorylated, and that phosphorylation is increased by phorbol ester stimulation of protein kinase C (PKC). Furthermore, by monitoring specific ECE-1 activity on the surface of live cells, we also show that following PKC activation, enzyme activity is significantly increased at the cell surface, where it is positioned to catalyse the generation of active endothelin. We believe this novel finding is unprecedented for a peptide processing enzyme. Indeed, this new knowledge regarding the control of endothelin production by regulating ECE-1 activity at the cell surface opens up a new area of endothelin biology and will provide novel insights into the physiology and pathophysiology of endothelin and endothelin-associated diseases. In addition, the information generated in these studies may provide valuable new insights into potential extra- and intracellular targets for the pharmacological and perhaps even therapeutic regulation of endothelin production and thus vascular tone. PMID:19617920

  8. Standardization of PCR-RFLP analysis of nsSNP rs1468384 of NPC1L1 gene

    Balgir Praveen; Khanna Divya; Kaur Gurlovleen

    2008-01-01

    Niemann-Pick C1-like 1 (NPC1L1) protein, a newly identified sterol influx transporter, located at the apical membrane of the enterocyte, which may actively facilitate the uptake of cholesterol by promoting the passage of sterols across the brush border membrane of the enterocyte. It effects intestinal cholesterol absorption and intracellular transport and as such is an integral part of complex process of cholesterol homeostasis. The study of population data for the distribution of these singl...

  9. Changes in vasopressin-converting aminopeptidase activity in the rat pineal gland during summer : Relationship to vasopressin contents

    Liu, B.; Burbach, J.P.H.

    1988-01-01

    Vasopressin (VP)-converting aminopeptidase (VP-AP) activity and VP contents were measured in single rat pineal glands during the summer of two successive years. The peptidase activity decreased significantly in August. The lowest activity (±SEM) of 0.18±0.02 pmol·hour−1 was recorded on August 14, co

  10. Modelling and control of a seven level NPC voltage source inverter. Application to high power induction machine drive

    Gheraia, H.; Berkouk, E. M.; Manesse, G.

    2001-08-01

    In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction.

  11. Modelling and control of a seven level NPC voltage source inverter. Application to high power induction machine drive

    Gheraia, H.; Berkouk, E.M. [ENP, Alger (Algeria). Lab. de Commande des Processus; Manesse, G. [CNAM-Paris (France). Lab. d' Electricite Industrielle

    2001-08-01

    In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction. (orig.)

  12. A novel active T-type three-level converter with open-circuit fault-tolerant control

    Choi, Uimin; Blaabjerg, Frede

    This paper proposes a novel active T-type three-level converter concept with fault-tolerant control. With the proposed topology, the converter can be operated continuously under open-circuit faults. It is shown that the proposed topology not only can keep its outputs under open-circuit fault......-point devices have the highest thermal stresses. The feasibility and effectiveness of the proposed topology concept are verified by the simulation results....

  13. Effect of Jatropha curcas Peptide Fractions on the Angiotensin I-Converting Enzyme Inhibitory Activity

    Maira R. Segura-Campos

    2013-01-01

    Full Text Available Hypertension is one of the most common worldwide diseases in humans. Angiotensin I-converting enzyme (ACE plays an important role in regulating blood pressure and hypertension. An evaluation was done on the effect of Alcalase hydrolysis of defatted Jatropha curcas kernel meal on ACE inhibitory activity in the resulting hydrolysate and its purified fractions. Alcalase exhibited broad specificity and produced a protein hydrolysate with a 21.35% degree of hydrolysis and 34.87% ACE inhibition. Ultrafiltration of the hydrolysate produced peptide fractions with increased biological activity (24.46–61.41%. Hydrophobic residues contributed substantially to the peptides’ inhibitory potency. The 5–10 and <1 kDa fractions were selected for further fractionation by gel filtration chromatography. ACE inhibitory activity (% ranged from 22.66 to 45.96% with the 5–10 kDa ultrafiltered fraction and from 36.91 to 55.83% with the <1 kDa ultrafiltered fraction. The highest ACE inhibitory activity was observed in F2 ( μg/mL from the 5–10 kDa fraction and F1 ( μg/mL from the <1 kDa fraction. ACE inhibitory fractions from Jatropha kernel have potential applications in alternative hypertension therapies, adding a new application for the Jatropha plant protein fraction and improving the financial viability and sustainability of a Jatropha-based biodiesel industry.

  14. A new configuration for multilevel converters with diode clamped topology

    Nami, A.; Zare, F.; Ledwich, G.; Ghosh, A.; Blaabjerg, Frede

    points in this type of converter is dc-voltage control. In this paper, a novel multi output dc-dc converter connected to a diode clamped topology is presented. This converter, for a given duty cycles, is able to regulate the capacitor voltage to provide an appropriate input voltage for NPC regardless of......Due to the increased use of renewable energy and power elctronic applications, more multilevel converters (MLC) are developed. A Neutral Point Clamped (NPC) inverter is one of the most used multilevel topologies for wind turbine (WT) and photovoltaic (PV) applications. One of the most crucial...... load changes which can avoid neutral point balancing problem in such converters. In addition, the presented topology is suitable for renewable energy systems to boost the low rectified output-voltage. In order to verify the proposed topology, steady state analysis, modelling and simulations are carried...

  15. Systemic overexpression of TNFα-converting enzyme does not lead to enhanced shedding activity in vivo.

    Masaki Yoda

    Full Text Available TNFα-converting enzyme (TACE/ADAM17 is a membrane-bound proteolytic enzyme with a diverse set of target molecules. Most importantly, TACE is indispensable for the release and activation of pro-TNFα and the ligands for epidermal growth factor receptor in vivo. Previous studies suggested that the overproduction of TACE is causally related to the pathogenesis of inflammatory diseases and cancers. To test this hypothesis, we generated a transgenic line in which the transcription of exogenous Tace is driven by a CAG promoter. The Tace-transgenic mice were viable and exhibited no overt defects, and the quantitative RT-PCR and Western blot analyses confirmed that the transgenically introduced Tace gene was highly expressed in all of the tissues examined. The Tace-transgenic mice were further crossed with Tace⁻/⁺ mice to abrogate the endogenous TACE expression, and the Tace-transgenic mice lacking endogenous Tace gene were also viable without any apparent defects. Furthermore, there was no difference in the serum TNFα levels after lipopolysaccharide injection between the transgenic mice and control littermates. These observations indicate that TACE activity is not necessarily dependent on transcriptional regulation and that excess TACE does not necessarily result in aberrant proteolytic activity in vivo.

  16. Early pharmacological inhibition of angiotensin-I converting enzyme activity induces obesity in adulthood

    Kely ede Picoli Souza

    2015-04-01

    Full Text Available We have investigated early programming of body mass in order to understand the multifactorial etiology of obesity. Considering that the renin-angiotensin system is expressed and functional in the white adipose tissue (WAT and modulates its development, we reasoned whether early transitory inhibition of angiotensin-I converting enzyme activity after birth could modify late body mass development. Therefore, newborn Wistar rats were treated with enalapril (10 mg/kg of body mass or saline, starting at the first day of life until the age of 16 days. Between days 90th and 180th, a group of these animals received high fat diet (HFD. Molecular, biochemical, histological and physiological data were collected. Enalapril treated animals presented hyperphagia, overweight and increased serum level of triglycerides, total cholesterol and leptin, in adult life. Body composition analyses revealed higher fat mass with increased adipocyte size in these animals. Molecular analyses revealed that enalapril treatment increases neuropeptide Y (NPY and cocaine- and amphetamine-regulated transcript (CART gene expression in hypothalamus, fatty acid synthase (FAS and hormone-sensitive lipase (HSL gene expression in retroperitoneal WAT and decreases peroxixome proliferators-activated receptor (PPAR γ, PPARα, uncoupling protein (UCP 2 and UCP3 gene expression in WAT. The results of the current study indicate that enalapril administration during early postnatal development increases body mass, adiposity and serum lipids in adulthood associated with enhanced food intake and decreased metabolic activity in WAT, predisposing to obesity in adulthood.

  17. Increased angiotensin-converting enzyme activity in the left ventricle after infarction

    V.C.W. Busatto

    1997-05-01

    Full Text Available An increase in angiotensin-converting enzyme (ACE activity has been observed in the heart after myocardial infarction (MI. Since most studies have been conducted in chronically infarcted individuals exhibiting variable degrees of heart failure, the present study was designed to determine ACE activity in an earlier phase of MI, before heart failure development. MI was produced in 3-month old male Wistar rats by ligation of the anterior branches of the left coronary artery, control rats underwent sham surgery and the animals were studied 7 or 15 days later. Hemodynamic data obtained for the anesthetized animals showed normal values of arterial blood pressure and of end-diastolic pressure in the right and left ventricular cavities of MI rats. Right and left ventricular (RV, LV muscle and scar tissue homogenates were prepared to determine ACE activity in vitro by measuring the velocity of His-Leu release from the synthetic substrate Hyp-His-Leu. ACE activity was corrected to the tissue wet weight and is reported as nmol His-Leu g-1 min-1. No significant change in ACE activity in the RV homogenates was demonstrable. A small nonsignificant increase of ACE activity (11 ± 9%; P0.05 was observed 7 days after MI in the surviving left ventricular muscle. Two weeks after surgery, however, ACE activity was 46 ± 11% (P<0.05 higher in infarcted rats compared to sham-operated rats. The highest ACE activity was demonstrable in the scar tissue homogenate. In rats studied two weeks after surgery, ACE activity in the LV muscle increased from 105 ± 7 nmol His-Leu g-1 min-1 in control hearts to 153 ± 11 nmol His-Leu g-1 min-1 (P<0.05 in the remaining LV muscle of MI rats and to 1051 ± 208 nmol His-Leu g-1 min-1 (P<0.001 in the fibrous scar. These data indicate that ACE activity increased in the heart after infarction before heart failure was demonstrable by hemodynamic measurements. Since the blood vessels of the scar drain to the remaining LV myocardium, the

  18. Increasing brain angiotensin converting enzyme 2 activity decreases anxiety-like behavior in male mice by activating central Mas receptors.

    Wang, Lei; de Kloet, Annette D; Pati, Dipanwita; Hiller, Helmut; Smith, Justin A; Pioquinto, David J; Ludin, Jacob A; Oh, S Paul; Katovich, Michael J; Frazier, Charles J; Raizada, Mohan K; Krause, Eric G

    2016-06-01

    Over-activation of the brain renin-angiotensin system (RAS) has been implicated in the etiology of anxiety disorders. Angiotensin converting enzyme 2 (ACE2) inhibits RAS activity by converting angiotensin-II, the effector peptide of RAS, to angiotensin-(1-7), which activates the Mas receptor (MasR). Whether increasing brain ACE2 activity reduces anxiety by stimulating central MasR is unknown. To test the hypothesis that increasing brain ACE2 activity reduces anxiety-like behavior via central MasR stimulation, we generated male mice overexpressing ACE2 (ACE2 KI mice) and wild type littermate controls (WT). ACE2 KI mice explored the open arms of the elevated plus maze (EPM) significantly more than WT, suggesting increasing ACE2 activity is anxiolytic. Central delivery of diminazene aceturate, an ACE2 activator, to C57BL/6 mice also reduced anxiety-like behavior in the EPM, but centrally administering ACE2 KI mice A-779, a MasR antagonist, abolished their anxiolytic phenotype, suggesting that ACE2 reduces anxiety-like behavior by activating central MasR. To identify the brain circuits mediating these effects, we measured Fos, a marker of neuronal activation, subsequent to EPM exposure and found that ACE2 KI mice had decreased Fos in the bed nucleus of stria terminalis but had increased Fos in the basolateral amygdala (BLA). Within the BLA, we determined that ∼62% of GABAergic neurons contained MasR mRNA and expression of MasR mRNA was upregulated by ACE2 overexpression, suggesting that ACE2 may influence GABA neurotransmission within the BLA via MasR activation. Indeed, ACE2 overexpression was associated with increased frequency of spontaneous inhibitory postsynaptic currents (indicative of presynaptic release of GABA) onto BLA pyramidal neurons and central infusion of A-779 eliminated this effect. Collectively, these results suggest that ACE2 may reduce anxiety-like behavior by activating central MasR that facilitate GABA release onto pyramidal neurons within the

  19. Angiotensin-converting enzyme inhibitory and antioxidant activities of enzymatically synthesized phenolic and vitamin glycosides.

    Charles, Rajachristu Einstein; Ponrasu, Thangavel; Sivakumar, Ramaiah; Divakar, Soundar

    2009-03-01

    Amyloglucosidase from Rhizopus mould and beta-glucosidase from sweet almond were employed for the preparation of phenolic and vitamin glycosides of vanillin, N-vanillylnonanamide, DL-dopa, dopamine, curcumin, alpha-tocopherol (vitamin E), pyridoxine (vitamin B(6)), ergocalciferol (vitamin D(2)), thiamin (vitamin B(1)) and riboflavin (vitamin B(2)). Approx. 20 enzymatically prepared phenolic and vitamin glycosides were subjected to ACE (angiotensin-converting enzyme) inhibition activity measurements, and 14 glycosides were tested for antioxidant activities. Both phenolic and vitamin glycosides exhibited IC(50) values for ACE inhibition in the 0.52+/-0.03-3.33+/-0.17 mM range and antioxidant activities ranging from 0.8+/-0.04 to 1.18+/-0.06 mM. Comparable ACE inhibition values were observed between free phenols and vitamin glycosides. However, antioxidant activities of glycosides were, in general, lesser than those of free phenols. Best IC(50) value for ACE inhibition were observed for 11-O-(D-fructofuranosyl)thiamin (0.52+/-0.03 mM), 3-hydroxy-4-O-(6-D-sorbitol)phenylalanine (0.56+/-0.03 mM), 4-O-(beta-D-glucopyranosyl)vanillin (0.61+/-0.03 mM), 4-O-(D-galactopyranosyl)vanillin (0.61+/-0.03 mM) and pyridoxine-D-glucoside (0.84+/-0.04 mM). Similarly, best IC(50) values for antioxidant activity were observed for 1,7-O-(bis-beta-D-glucopyranosyl)curcumin (0.8+/-0.04 mM), 4-O-(beta-D-glucopyranosyl)vanillin (0.9+/-0.05 mM), 3-hydroxy-4-O-(beta-D-galactopyranosyl-(1'-->4)beta-D-glucopyranosyl)phenylalanine (0.9+/-0.05 mM), 20-O-(D-glucopyranosyl)ergocalciferol (0.9+/-0.05 mM) and dopamine-D-galactoside (0.93+/-0.05 mM). PMID:18547170

  20. NREL Pyrheliometer Comparisons: September 22-26, 2014 (NPC-2014)

    Reda, I.; Dooraghi, M.; Habte, A.

    2014-10-01

    Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements. As with all measurement systems, absolute cavity radiometers and other types of pyrheliometers are subject to performance changes over time. NREL has developed and maintained a select group of absolute cavity radiometers with direct calibration traceability to the World Radiometric Reference (WRR), and uses these reference instruments to calibrate pyrheliometers and pyranometers using the ISO 17025 accredited Broadband Outdoor Radiometer Calibration (BORCAL) process. National Renewable Energy Laboratory (NREL) pyrheliometer comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners and operators, each NPC provides an opportunity to determine the unique WRR transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the WRR. NPC-2014 was held September 22-26, 2014. Participants operated 36 absolute cavity radiometers and 22 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky direct normal solar irradiance during this period, and this report documents the findings.

  1. Chinese medicinal formula Fufang Xueshuantong capsule could inhibit the activity of angiotensin converting enzyme

    Sheng, Shujing; Wang, Yonggang; Long, Chaofeng; Su, Weiwei; Rong, Xia

    2014-01-01

    Fufang Xueshuantong (FXST) capsule, a Chinese medicinal formula composed of four herbals – Panax notoginseng, Radix Astragali, Radix Salvia Miltiorrhizae and Radix Scrophulariaceae, has been used to treat cardiovascular diseases for many years, but the pharmacological mechanisms underlying its effects has not been clarified. This study investigates if a connection between FXST and angiotensin converting enzyme (ACE) might be an explanation for its pharmacological effects. ACE inhibition assay was performed on FXST capsule, 50% ethanol extracts from the four herbals and three selected saponins most abundant in P. notoginseng (Ginsenoside Rg1, Ginsenoside Rb1 and Notoginsenoside R1) using a biochemical test. Reversed-phase high-performance liquid chromatography of liberated hippuric acid from the ACE assay was conducted to determine the inhibitory effect. As a result, FXST and extracts from P. notoginseng showed a significant and dose-dependent inhibition on ACE activity with the IC50 values of 115 μg/ml and 179 μg/ml, respectively. But extracts from the other three herbals and the three selected saponins had no significant effect on ACE inhibition. Compared to other reported plant extracts, FXST could be considered as an effective ACE inhibitor. The inhibition of ACE activity supports the traditional use of FXST on blood circulation and the inhibitory property of FXST is mainly caused by P. notoginseng. PMID:26019516

  2. Association of circulating angiotensin converting enzyme activity with respiratory muscle function in infants

    Onufriou Anny

    2010-05-01

    Full Text Available Abstract Background Angiotensin converting enzyme (ACE gene contains a polymorphism, consisting of either the presence (I or absence (D of a 287 base pair fragment. Deletion (D is associated with increased circulating ACE (cACE activity. It has been suggested that the D-allele of ACE genotype is associated with power-oriented performance and that cACE activity is correlated with muscle strength. Respiratory muscle function may be similarly influenced. Respiratory muscle strength in infants can be assessed specifically by measurement of the maximum inspiratory pressure during crying (Pimax. Pressure-time index of the respiratory muscles (PTImus is a non-invasive method, which assesses the load to capacity ratio of the respiratory muscles. The objective of this study was to determine whether increased cACE activity in infants could be related to greater respiratory muscle strength and to investigate the potential association of cACE with PTImus measurements as well as the association of ACE genotypes with cACE activity and respiratory muscle strength in this population. Methods Serum ACE activity was assayed by using a UV-kinetic method. ACE genotyping was performed by polymerase chain reaction amplification, using DNA from peripheral blood. PTImus was calculated as (Pimean/Pimax × (Ti/Ttot, where Pimean was the mean inspiratory pressure estimated from airway pressure, generated 100 milliseconds after an occlusion (P0.1, Pimax was the maximum inspiratory pressure and Ti/Ttot was the ratio of the inspiratory time to the total respiratory cycle time. Pimax was the largest pressure generated during brief airway occlusions performed at the end of a spontaneous crying effort. Results A hundred and ten infants were studied. Infants with D/D genotype had significantly higher serum ACE activity than infants with I/I or I/D genotypes. cACE activity was significantly related to Pimax and inversely related to PTImus. No association between ACE genotypes and

  3. Control of high power IGBT modules in the active region for fast pulsed power converters

    Cravero, J M; Garcia Retegui, R; Maestri, S; Uicich, G

    2014-01-01

    At CERN, fast pulsed power converters are used to supply trapezoidal current in different magnet loads. These converters perform output current regulation by using a high power IGBT module in its ohmic region. This paper presents a new strategy for pulsed current control applications using a specifically designed IGBT driver.

  4. A new high-performance AC/DC power factor correction switching converter based on one-cycle control technology and active floating-charge technology

    GAO Chao

    2008-01-01

    A new family of converters, high-performance AC/DC power factor correction (PFC) switching converters with one-cycle control technology and active floating-charge technology, was derived and experimentally verified. The topology of a single-phase CCM and DCM Boost-PFC switching converter was also analyzed. Its operating prniciples and control methods were expounded. Based on these, a new type of AC/DC switching converter circuits for PFC combined with one-cycle control technology was presented herein. The proposed AC/DC switching converter significantly helps improve the converter efficiency and its power factor value.

  5. Development and validation of quality of life scale of nasopharyngeal carcinoma patients: the QOL-NPC (version 2)

    Su, Yong; Mo, Chuan-wei; Cheng, Wan-qin; Wang, Lei; Xu, Qian; Wu, Zu-chun; Wu, Zhe-li; Liu, Li-Zhi; Chen, Xin-lin

    2016-01-01

    Background The aim was to develop and validate the quality of life scale for nasopharyngeal carcinoma (NPC) patients, the QOL-NPC (version 2), a specific instrument to measure quality of life for NPC patients. Methods The QOL-NPC was developed and validated according to standard procedures. The patients were assessed using the QOL-NPC, FACT-G, and FACT-H&N. Classical test theory was used to evaluate the reliability, validity, and responsiveness of the QOL-NPC. Results A total of 487 patients ...

  6. Control strategy for three-phase four-wire PWM converter of integrated voltage compensation type active SFCL

    The integrated voltage compensation type active superconducting fault current limiter (SFCL) is composed of three air-core superconducting transformers and a three-phase four-wire PWM converter. In order to realize the current-limiting characteristics of the integrated active SFCL, it is needed to control the three-phase four-wire PWM converter flexibly and reasonably. Thereby, the control strategy for the converter is analyzed in this paper. In dq0 reference frame, the mathematical model of the converter is founded. The double-loop control strategy, consisting of voltage outer loop and current inner loop, is presented. Moreover, the voltage balance control for the split DC link capacitors is also considered. Using MATLAB, the simulation model of the integrated active SFCL is built. According to the simulation results, it is known that, the presented control strategy is feasible and valid, and the converter can work well under unsymmetrical and symmetrical fault conditions, and then the fault current can be limited quickly and effectively.

  7. Angiotensin-Converting Enzyme Inhibitors and Active Tuberculosis: A Population-Based Study.

    Wu, Jiunn-Yih; Lee, Meng-Tse Gabriel; Lee, Si-Huei; Lee, Shih-Hao; Tsai, Yi-Wen; Hsu, Shou-Chien; Chang, Shy-Shin; Lee, Chien-Chang

    2016-05-01

    Numerous epidemiological data suggest that the use of angiotensin-converting enzyme inhibitors (ACEis) can improve the clinical outcomes of pneumonia. Tuberculosis (TB) is an airborne bacteria like pneumonia, and we aimed to find out whether the use of ACEis can decrease the risk of active TB.We conducted a nested case-control analysis by using a 1 million longitudinally followed cohort, from Taiwan national health insurance research database. The rate ratios (RRs) for TB were estimated by conditional logistic regression, and adjusted using a TB-specific disease risk score (DRS) with 71 TB-related covariates.From January, 1997 to December, 2011, a total of 75,536 users of ACEis, and 7720 cases of new active TB were identified. Current use (DRS adjusted RR, 0.87 [95% CI, 0.78-0.97]), but not recent and past use of ACEis, was associated with a decrease in risk of active TB. Interestingly, it was found that chronic use (>90 days) of ACEis was associated with a further decrease in the risk of TB (aRR, 0.74, [95% CI, 0.66-0.83]). There was also a duration response effect, correlating decrease in TB risk with longer duration of ACEis use. The decrease in TB risk was also consistent across all patient subgroups (age, sex, heart failure, cerebrovascular diseases, myocardial infraction, renal diseases, and diabetes) and patients receiving other cardiovascular medicine.In this large population-based study, we found that subjects with recent and chronic use of ACEis were associated with decrease in TB risk. PMID:27175655

  8. Control of modular multilevel converters for grid integration of full-scale wind energy conversion systems

    Debnath, Suman

    The growing demand for wind power generation has pushed the capacity of wind turbines towards MW power levels. Higher capacity of the wind turbines necessitates operation of the generators and power electronic conversion systems at higher voltage/power levels. The power electronic conversion system of a wind energy conversion system (WECS) needs to meet the stringent requirements in terms of reliability, efficiency, scalability and ease of maintenance, power quality, and dv/dt stress on the generator/transformer. Although the multilevel converters including the neutral point clamped (NPC) converter and the active NPC converter meet most of the requirements, they fall short in reliability and scalability. Motivated by modularity/scalability feature of the modular multilevel converter (MMC), this research is to enable the MMC to meet all of the stringent requirements of the WECS by addressing their unique control challenges. This research presents systematic modeling and control of the MMC to enable it to be a potential converter topology for grid integration of full-scale WECSs. Based on the developed models, appropriate control systems for control of circulating current and capacitor voltages under fixed- and variable-frequency operations are proposed. Using the developed MMC models, a gradient-based cosimulation algorithm to optimize the gains of the developed control systems, is proposed. Performance/effectiveness of the developed models and the proposed control systems for the back-to-back MMC-based WECS are evaluated/verified based on simulations studies in the PSCAD/EMTDC software environment and experimental case studies on a laboratory-scale hardware prototype.

  9. Decoupled Control Of Active And Reactive Powers Of DFIG With Cascaded SPWM Converters.

    K.H.Phani Shree

    2011-10-01

    Full Text Available This paper presents the dynamic modeling and simulation of a doubly fed induction generator (DFIG driven by wind turbine connected with cascaded converters. A doubly fed induction generator is basically a standard, wound rotor induction machine with its stator windings directly connected to the grid and its rotor windings connected to the grid through converters. Vector control technique is used to obtain decoupled control for powers. This paper investigates on the performance of DFIG with cascaded SPWM inverters. The total harmonic distortion has been calculated with different converters. The model is developed in MATLAB/SIMULINK environment.

  10. Analysis of Parallel Topology for Active Power Factor Correction Using Single and Dual Mode Boost Converters

    Md. Mosfiqur Rahaman

    2014-11-01

    Full Text Available The ratio between real or average power and apparent power known as power factor has a high impact on power system industries. Efficient usage of the real power is very indicative in developing a power system. With the profusely development of technology in power semiconductor devices, the rate of using power electronic systems has expanded to new and wide application range that include residential, commercial, aerospace and other systems. In the nonlinear system, loads are the main source of harmonics. So that nonlinear behavior puts a question mark on their high efficiency. The current drawn by power electronic interfaces from the line is distorted resulting in a high total Harmonic Distortion and low p.f. this creates adverse effects on the power system include increased magnitudes of neutral currents in three phase systems, overheating in transformers and induction motors. This paper aims to develop a circuit for PFC by using active filtering approach by implementing two (single & dual boost converters arranged in parallel, for improving circuit quality and switching loss. This work actually involves simulation of basic power electronic circuit and it starts with simple circuit with a gradual increase in complexity by inclusion of new components and their subsequent effect on current and voltage wave forms. We focused to improve the condition of input current waveforms for making it sinusoidal by tuning the circuits.

  11. Angiotensin-I Converting Enzyme (ACE) Inhibitory and Anti-Oxidant Activities of Sea Cucumber (Actinopyga lecanora) Hydrolysates

    Raheleh Ghanbari; Mohammad Zarei; Afshin Ebrahimpour; Azizah Abdul-Hamid; Amin Ismail; Nazamid Saari

    2015-01-01

    In recent years, food protein-derived hydrolysates have received considerable attention because of their numerous health benefits. Amongst the hydrolysates, those with anti-hypertensive and anti-oxidative activities are receiving special attention as both activities can play significant roles in preventing cardiovascular diseases. The present study investigated the angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities of Actinopyga lecanora (A. lecanora) hydrolysates,...

  12. An oncolytic adenovirus in combination with radiation treatment (RT) for nasopharyngeal carcinoma (NPC)

    We have succeeded in regulating gene expression in nasopharyngeal carcinoma (NPC) by exploiting the exclusive presence of the Epstein Barr virus (EBV) genome in the cancer cells. When the latently expressed EBV-gene product, EBNA-1, binds to a family of repeats (FR) sequence, located in the oriP of the EBV genome (oriP-FR), this results in transcriptional activation of downstream genes. Based on these observations we designed a transcriptional targeting strategy that now allows for the construction of a conditionally replicating adenovirus under the control of the oriP-FR promoter. Results: Cloning the E1A transcriptional unit downstream of the EBV-responsive, oriP-FR promoter sequence generated the novel adenovirus adv.oriP.E1A. E1A protein expression using Western blot analysis demonstrated a time-dependent increase in expression in the EBV-positive C666-1 cells, in contrast to minimal expression in EBV-negative NPC cells. The MTT assay showed a dose-dependent cytotoxic effect of adv.oriP.E1A in the C666-1 cells, and the combination with 6 Gy of ionizing radiation resulted in an additive cytotoxic effect. In contrast, no evidence of cytotoxicity was observed in a panel of four other human cell lines after adv.oriP.E1A treatment. Western blotting for adenoviral fiber knob protein demonstrated a time-dependent increase in expression, consistent with viral replication; this was confirmed using quantitative real-time PCR. Ex-vivo infection of C666-1 cells with adv.oriP.E1A inhibited tumor formation for at least 100 days after intramuscular injection as compared to control cells that established palpable tumors one week after injection. Treatment of established C666-1 tumours with six intratumoral injections of 2 x 109 pfu adv.oriP.E1A in combination with 2 x 4 Gy radiation therapy (RT) resulted in complete regression for 3-weeks. Conclusion: We have successfully constructed a novel selectively oncolytic virus for EBV-positive NPC cells, demonstrating significant

  13. Inhibitory effects of kiwifruit extract on human platelet aggregation and plasma angiotensin-converting enzyme activity.

    Dizdarevic, Lili L; Biswas, Dipankar; Uddin, M D Main; Jørgenesen, Aud; Falch, Eva; Bastani, Nasser E; Duttaroy, Asim K

    2014-01-01

    Previous human studies suggest that supplementation with kiwifruits lowers several cardiovascular risk factors such as platelet hyperactivity, blood pressure and plasma lipids. The cardiovascular health benefit of fruit and vegetables is usually attributed to the complex mixture of phytochemicals therein; however, kiwifruit's cardioprotective factors are not well studied. In this study, we investigated the effects of kiwifruit extract on human blood platelet aggregation and plasma angiotensin-converting enzyme (ACE) activity. A sugar-free, heat-stable aqueous extract with molecular mass less than 1000 Da was prepared from kiwifruits. Typically, 100 g kiwifruits produced 66.3 ± 5.8 mg (1.2 ± 0.1 mg CE) of sugar-free kiwifruit extract (KFE). KFE inhibited both human platelet aggregation and plasma ACE activity in a dose-dependent manner. KFE inhibited platelet aggregation in response to ADP, collagen and arachidonic acid, and inhibitory action was mediated in part by reducing TxA2 synthesis. The IC50 for ADP-induced platelet aggregation was 1.6 ± 0.2 mg/ml (29.0 ± 3.0 μg CE/ml), whereas IC50 for serum ACE was 0.6 ± 0.1 mg/ml (11.0 ± 1.2 μg CE/ml). Consuming 500 mg of KFE (9.0 mg CE) in 10 g margarine inhibited ex vivo platelet aggregation by 12.7%, 2 h after consumption by healthy volunteers (n = 9). All these data indicate that kiwifruit contains very potent antiplatelet and anti-ACE components. Consuming kiwifruits might be beneficial as both preventive and therapeutic regime in cardiovascular disease. PMID:24219176

  14. Kinetic imaging of NPC1L1 and sterol trafficking between plasma membrane and recycling endosomes in hepatoma cells

    Hartwig Petersen, Nicole; Færgeman, Nils J; Yu, Liqing;

    2008-01-01

    Niemann-Pick C1-like 1 (NPC1L1) is a recently identified protein that mediates intestinal cholesterol absorption and regulates biliary cholesterol excretion. The itineraries and kinetics of NPC1L1 trafficking remain uncertain. In this study, we have visualized movement of NPC1L1-enhanced green...... exclusively in the canalicular membrane, where the protein is highly mobile. Our study demonstrates dynamic trafficking of NPC1L1 between cell surface and intracellular compartments and suggests that this transport is involved in NPC1L1 mediated cellular sterol uptake....... fluorescent protein (NPC1L1-EGFP) and cholesterol analogues in hepatoma cells. At steady state about 42% of NPC1L1 resided in the transferrin (Tf) positive, sterol enriched endocytic recycling compartment (ERC), while time-lapse microscopy demonstrated NPC1L1 traffic between plasma membrane and ERC...

  15. Buck-boost converter for simultaneous semi-active vibration control and energy harvesting for electromagnetic regenerative shock absorber

    Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

    2014-04-01

    Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.

  16. Changes in vasopressin-converting aminopeptidase activity in the rat pineal gland during summer : Relationship to vasopressin contents

    Liu, B; Burbach, J. P. H.

    1988-01-01

    Vasopressin (VP)-converting aminopeptidase (VP-AP) activity and VP contents were measured in single rat pineal glands during the summer of two successive years. The peptidase activity decreased significantly in August. The lowest activity (±SEM) of 0.18±0.02 pmol·hour−1 was recorded on August 14, compared to the basal activity of 0.25±0.01 pmol·hour−1 in July and September of 1986. The change with similar percentage occurred in the same period of 1987. The specific activity of the enzyme in t...

  17. NREL Pyrheliometer Comparison: September 16 to 27, 2013 (NPC-2013)

    Reda, I.; Dooraghi, M.; Habte, A.

    2013-11-01

    Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for the development and deployment of solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations traceable to an international standard is the first step in producing research-quality solar irradiance measurements. As with all measurement systems, absolute cavity radiometers and other types of pyrheliometers are subject to performance changes over time. NREL has developed and maintained a group of absolute cavity radiometers with direct calibration traceability to the World Radiometric Reference (WRR). These reference instruments are used by NREL to calibrate pyrheliometers and pyranometers using the ISO 17025 accredited Broadband Outdoor Radiometer Calibration (BORCAL) process (Reda et al. 2008). NPCs are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners/operators, e.g. NREL, NASA, NIST, NOAA, USA industry and academia, USA-DOE and other national laboratories, and national and international organizations. Each NPC provides an opportunity to determine the unique World Radiometric Reference (WRR) transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the International System of Units through WRR.

  18. High Frequency AC Inductor Analysis and Design for Dual Active Bridge (DAB) Converters

    Zhang, Zhe; Andersen, Michael A. E.

    2016-01-01

    component in DAB converters or DAB’s derivative topologies for transferring energy between the primary and secondary sides. The DAB converter’s operation principles, and the corresponding voltage and current stresses over its ac inductor are analyzed. Hereby, six diverse winding arrangements are studied in...

  19. Electro-thermal modeling for junction temperature cycling-based lifetime prediction of a press-pack IGBT 3L-NPC-VSC applied to large wind turbines

    Senturk, Osman S.; Munk-Nielsen, Stig; Teodorescu, Remus; Helle, L.; Rodríguez Cortés, Pedro

    2011-01-01

    Reliability is a critical criterion for multi-MW wind turbines, which are being employed with increasing numbers in wind power plants, since they operate under harsh conditions and have high maintenance cost due to their remote locations. In this study, the wind turbine grid-side converter reliability is investigated regarding IGBT lifetime based on junction temperature cycling for the grid-side press-pack IGBT 3L-NPC-VSC, which is a state-of-the art high reliability s...

  20. Design of a Modular Multilevel Converter as an Active Front-End for a magnet supply application

    Panagiotis, Asimakopoulos; Massimo, Bongiorno

    2015-01-01

    The aim of this work is to describe the general design procedure of a Modular Multilevel Converter (MMC) applied as an Active Front-End (AFE) for a magnet supply for beam accelerators. The dimensioning criteria for the converter and the dc-link capacitance are presented and the grid transformer requirements are set. Considering the converter design, the arm inductance calculation is based on the specifications for the arm-current ripple and the DC-link fault tolerance, but, also, on the limitation of the second harmonic and the second-order LC resonance of the arm current. The module capacitance value is evaluated by focusing on the required switching dynamics and the capacitor-voltage ripple according to a newly proposed graphical method. The loading of each semiconductor in the half bridge is calculated via simulation, indicating the unsymmetrical current distribution. It is concluded that the current distribution for each semiconductor depends on the mode of operation of the converter. The different criter...

  1. Active Power Control with Undead-Band Voltage & Frequency Droop for HVDC Converters in Large Meshed DC Grids

    Vrana, Til Kristian; Zeni, Lorenzo; Fosso, Olav Bjarte

    A new control method for large meshed HVDC grids has been developed, which helps to keep the active power balance at the AC and the DC side. The method definition is kept wide, leaving the possibility for control parameter optimisation. Other known control methods can be seen as specific examples...... of the proposed method. It can serve as a framework for the control of large DC grids, defining a common standard for the control scheme, but still leaving a lot of freedom for individual adjustments. The proposed method is based on a so called “undead”-band, meaning that control activity is reduced...... within the band, but not set to zero as with a regular dead-band. It operates with a minimum of required communication. New converters can be added to the system without changing the control of the other individual converters. It is well suited to achieve high reliability standards due to the distributed...

  2. Implementation Of A Battery Storage System Of An Individual Active Power Control Based On A Cascaded Multilevel Pwm Converter

    RAJASEKHARACHARI K, G.BALASUNDARAM, KUMAR K

    2013-07-01

    Full Text Available For The Smart Grid Arrangement A Battery Energy Storage System Is Important Equipment Of Renewable Energy Resources. In This Paper We Will Have A Discussion On Active Power Control In A Battery Storage System With A Topology Of Cascaded Multi Level Inverter With Pulse Width Modulation Switching Technique. Multilevel Inverters Have Been Attracting In Favor Of Academia As Well As Industry In The Recent Decade For High-Power And Medium-Voltage Energy Control. A Battery Energy Storage System (BESS, Combining Battery Packs With A Power Converter And Control, Should Be Installed In The Vicinity Of An Intermittent Energy Source. Here We Can Control The Active Power As Individually In A Converter Cell Battery Arrangement Unit, By This We Can Have A Advantage Of Charging And Discharging Of A Battery Units At Different Power Levels. The Charging/Discharging Of The Battery In A Dc Form Can Be Shown In This Paper. From The Controlling Of Active Power As In A Individual Converter Cells We Will Get Maximum Utilization Of Battery Power To The Load As Required. If We Will Get A Less Harmonic Content In The Output Voltage Definitely We Can Improve The Utilization Part, So This Can Be Obtain By Getting The Multiple Level Of Voltage As Approximately Sinusoidal With Maximum Reduction Of Harmonics. The Simulation Results For This Proposed System Have Been Shown In This And Also Multiple Levels Of Voltages In Output Can Be Shown In This Paper.

  3. Why is plasma angiotensin-converting enzyme activity elevated in hyperthyroidism?

    Roulston, J. E.; Gold, A; Wright, M.; Walker, S. W.

    1987-01-01

    The elevation in plasma angiotensin-converting enzyme (ACE) levels observed in patients with hyperthyroidism is unexplained. In this study three hypotheses were investigated. Results from a study using rats treated with thyroid hormones indicated that the increased ACE was not due to increased cleavages of enzyme from lung endothelia. Data from patients with specific tissue damage argue against a nonspecific release of ACE from damaged cells. Data from cultured cell experiments, however, stro...

  4. Angiotensin-I Converting Enzyme (ACE) Inhibitory and Anti-Oxidant Activities of Sea Cucumber (Actinopyga lecanora) Hydrolysates.

    Ghanbari, Raheleh; Zarei, Mohammad; Ebrahimpour, Afshin; Abdul-Hamid, Azizah; Ismail, Amin; Saari, Nazamid

    2015-01-01

    In recent years, food protein-derived hydrolysates have received considerable attention because of their numerous health benefits. Amongst the hydrolysates, those with anti-hypertensive and anti-oxidative activities are receiving special attention as both activities can play significant roles in preventing cardiovascular diseases. The present study investigated the angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities of Actinopyga lecanora (A. lecanora) hydrolysates, which had been prepared by alcalase, papain, bromelain, flavourzyme, pepsin, and trypsin under their optimum conditions. The alcalase hydrolysate showed the highest ACE inhibitory activity (69.8%) after 8 h of hydrolysis while the highest anti-oxidative activities measured by 2,2-diphenyl 1-1-picrylhydrazyl radical scavenging (DPPH) (56.00%) and ferrous ion-chelating (FIC) (59.00%) methods were exhibited after 24 h and 8 h of hydrolysis, respectively. The ACE-inhibitory and anti-oxidative activities displayed dose-dependent trends, and increased with increasing protein hydrolysate concentrations. Moreover, strong positive correlations between angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities were also observed. This study indicates that A. lecanora hydrolysate can be exploited as a source of functional food owing to its anti-oxidant as well as anti-hypertension functions. PMID:26690117

  5. Angiotensin-I Converting Enzyme (ACE Inhibitory and Anti-Oxidant Activities of Sea Cucumber (Actinopyga lecanora Hydrolysates

    Raheleh Ghanbari

    2015-12-01

    Full Text Available In recent years, food protein-derived hydrolysates have received considerable attention because of their numerous health benefits. Amongst the hydrolysates, those with anti-hypertensive and anti-oxidative activities are receiving special attention as both activities can play significant roles in preventing cardiovascular diseases. The present study investigated the angiotensin-I converting enzyme (ACE inhibitory and anti-oxidative activities of Actinopyga lecanora (A. lecanora hydrolysates, which had been prepared by alcalase, papain, bromelain, flavourzyme, pepsin, and trypsin under their optimum conditions. The alcalase hydrolysate showed the highest ACE inhibitory activity (69.8% after 8 h of hydrolysis while the highest anti-oxidative activities measured by 2,2-diphenyl 1-1-picrylhydrazyl radical scavenging (DPPH (56.00% and ferrous ion-chelating (FIC (59.00% methods were exhibited after 24 h and 8 h of hydrolysis, respectively. The ACE-inhibitory and anti-oxidative activities displayed dose-dependent trends, and increased with increasing protein hydrolysate concentrations. Moreover, strong positive correlations between angiotensin-I converting enzyme (ACE inhibitory and anti-oxidative activities were also observed. This study indicates that A. lecanora hydrolysate can be exploited as a source of functional food owing to its anti-oxidant as well as anti-hypertension functions.

  6. Medium Voltage Three-level Converters for the Grid Connection of aMulti-MW Wind Turbine

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig; Rodriguez, Pedro; Teodorescu, Remus

    2009-01-01

    Three-level (3L) neutral point clamped (NPC), flying capacitor (FC), and H-bridge (HB) voltage source converters (VSCs) as a grid-side full-scale medium voltage (MV) converter are modeled, controlled, and simulated for the grid connection of a hypothetical 6MW wind turbine. Via the converter...... connection circuit (without capacitive switching ripple filters), the 3L-HB-VSC is expected to be superior with respect to power density and reliability over the 3L-NPC- and -FC-VSCs....

  7. Medium voltage three-level converters for the grid connection of a multi-MW wind turbine

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig; Rodrihuez, Pedro; Teodorescu, Remus

    Three-level (3L) neutral point clamped (NPC), flying capacitor (FC), and H-bridge (HB) voltage source converters (VSCs) as a grid-side full-scale medium voltage (MV) converter are modeled, controlled, and simulated for the grid connection of a hypothetical 6MW wind turbine. Via the converter...... connection circuit (without capacitive switching ripple filters), the 3L-HB-VSC is expected to be superior with respect to power density and reliability over the 3L-NPC- and -FC-VSCs....

  8. Effects on plasma angiotensin-converting enzyme activity and circulating renin of lisinopril and enalapril alone and in combination with propranolol in healthy volunteers

    Hansen, Erik Feldager; Bendtsen, Flemming; Henriksen, Jens Henrik

    1999-01-01

    The effects on plasma angiotensin-converting enzyme activity and renin activity of the two long-acting angiotensin-converting enzyme inhibitors, lisinopril and enalapril, alone and in combination with propranolol were studied. In an open, randomised, cross-over design 12 healthy volunteers received...... orally enalapril 20 mg alone, enalapril 20 mg in combination with propranolol 80 mg, lisinopril 20 mg alone, and lisinopril 20 mg in combination with propranolol 80 mg. Plasma angiotensin-converting enzyme activity and plasma renin activity were measured for 24 h after each treatment period. Lisinopril...

  9. DC activated via dectin-1 convert Treg into IL-17 producers

    Osorio, Fabiola; LeibundGut-Landmann, Salomé; Lochner, Matthias; Lahl, Katharina; Sparwasser, Tim; Eberl, Gérard; Reis e Sousa, Caetano

    2008-01-01

    Th cells producing IL-17 play a pro-inflammatory role at mucosal surfaces. Treg at the same sites dampen inflammation and prevent immunopathology. Th cells producing IL-17 (Th17) and Treg are thought to be distinct populations defined by expression of the transcription factors ROR-γt and Foxp3, respectively. Here, we show that mouse CD25+Foxp3+ Treg can be converted into a hybrid T-cell population characterized by the expression of Foxp3 and ROR-γt and the production of IL-17. Conversion was ...

  10. Characterisation of two deletions involving NPC1 and flanking genes in Niemann-Pick type C disease patients.

    Rodríguez-Pascau, Laura; Toma, Claudio; Macías-Vidal, Judit; Cozar, Mónica; Cormand, Bru; Lykopoulou, Lilia; Coll, Maria Josep; Grinberg, Daniel; Vilageliu, Lluïsa

    2012-12-01

    Niemann-Pick type C (NPC) disease is an autosomal recessive lysosomal disorder characterised by the accumulation of a complex pattern of lipids in the lysosomal-late endosomal system. More than 300 disease-causing mutations have been identified so far in the NPC1 and NPC2 genes, including indel, missense, nonsense and splicing mutations. Only one genomic deletion, of more than 23 kb, has been previously reported. We describe two larger structural variants, encompassing NPC1 and flanking genes, as a cause of the disease. QMPSF, SNP inheritance and CytoScan® HD Array were used to confirm and further characterise the presence of hemizygous deletions in two patients. One of the patients (NPC-57) bore a previously described missense mutation (p.T1066N) and an inherited deletion that included NPC1, C18orf8 and part of ANKRD29 gene. The second patient (NPC-G1) had a 1-bp deletion (c.852delT; p.F284Lfs*26) and a deletion encompassing the promoter region and exons 1-10 of NPC1 and the adjacent ANKRD29 and LAMA3. This study characterised two novel chromosomal microdeletions at 18q11-q12 that cause NPC disease and provide insight into missing NPC1 mutant alleles. PMID:23142039

  11. Analysis and design of a parallel-connected single active bridge DC-DC converter for high-power wind farm applications

    Park, Kiwoo; Chen, Zhe

    2013-01-01

    This paper presents a parallel-connected Single Active Bridge (SAB) dc-dc converter for high-power applications. Paralleling lower-power converters can lower the current rating of each modular converter and interleaving the outputs can significantly reduce the magnitudes of input and output current...... ripples without increasing switching losses or device stresses. Analysis of both the input and output current characteristics and design aspects of the transformer, the filter inductor, and the input and output filter capacitors will be presented. Considering the high maintenance cost and fault tolerant...... requirements, this modular converter concept is expected to be highly beneficial especially for the offshore wind farm application....

  12. Analysis and Comparison Based on Component Stress Factor of Dual Active Bridge and Isolated Full Bridge Boost Converters for Bidirectional Fuel Cells Systems

    Pittini, Riccardo; Mira Albert, Maria del Carmen; Zhang, Zhe;

    2014-01-01

    This paper presents an analysis and comparison of isolated topologies for bidirectional fuel cell systems. The analyzed topologies are the dua l active bridge (DAB) and the isolated full bridge boost converter (IFBBC). The analysis is performed based on the component stress factor (CSF). Results...... highlight that the DAB has lower CSF than the IFBBC for narrow converter operating points. On the other hand the IFBBC presents a more homogeneous CSF over the entire converter operating range. Finally, experimental results obtained from a 30-80 V 80 A 6 kW 40 kHz IFBBC are presented. The converter achieves...

  13. Dectin-1 Activation by a Natural Product β-Glucan Converts Immunosuppressive Macrophages into an M1-like Phenotype.

    Liu, Min; Luo, Fengling; Ding, Chuanlin; Albeituni, Sabrin; Hu, Xiaoling; Ma, Yunfeng; Cai, Yihua; McNally, Lacey; Sanders, Mary Ann; Jain, Dharamvir; Kloecker, Goetz; Bousamra, Michael; Zhang, Huang-ge; Higashi, Richard M; Lane, Andrew N; Fan, Teresa W-M; Yan, Jun

    2015-11-15

    Tumor-associated macrophages (TAM) with an alternatively activated phenotype have been linked to tumor-elicited inflammation, immunosuppression, and resistance to chemotherapies in cancer, thus representing an attractive target for an effective cancer immunotherapy. In this study, we demonstrate that particulate yeast-derived β-glucan, a natural polysaccharide compound, converts polarized alternatively activated macrophages or immunosuppressive TAM into a classically activated phenotype with potent immunostimulating activity. This process is associated with macrophage metabolic reprograming with enhanced glycolysis, Krebs cycle, and glutamine utilization. In addition, particulate β-glucan converts immunosuppressive TAM via the C-type lectin receptor dectin-1-induced spleen tyrosine kinase-Card9-Erk pathway. Further in vivo studies show that oral particulate β-glucan treatment significantly delays tumor growth, which is associated with in vivo TAM phenotype conversion and enhanced effector T cell activation. Mice injected with particulate β-glucan-treated TAM mixed with tumor cells have significantly reduced tumor burden with less blood vascular vessels compared with those with TAM plus tumor cell injection. In addition, macrophage depletion significantly reduced the therapeutic efficacy of particulate β-glucan in tumor-bearing mice. These findings have established a new paradigm for macrophage polarization and immunosuppressive TAM conversion and shed light on the action mode of β-glucan treatment in cancer. PMID:26453753

  14. Combined Chemical Activation and Fenton Degradation to Convert Waste Polyethylene into High-Value Fine Chemicals.

    Chow, Cheuk-Fai; Wong, Wing-Leung; Ho, Keith Yat-Fung; Chan, Chung-Sum; Gong, Cheng-Bin

    2016-07-01

    Plastic waste is a valuable organic resource. However, proper technologies to recover usable materials from plastic are still very rare. Although the conversion/cracking/degradation of certain plastics into chemicals has drawn much attention, effective and selective cracking of the major waste plastic polyethylene is extremely difficult, with degradation of C-C/C-H bonds identified as the bottleneck. Pyrolysis, for example, is a nonselective degradation method used to crack plastics, but it requires a very high energy input. To solve the current plastic pollution crisis, more effective technologies are needed for converting plastic waste into useful substances that can be fed into the energy cycle or used to produce fine chemicals for industry. In this study, we demonstrate a new and effective chemical approach by using the Fenton reaction to convert polyethylene plastic waste into carboxylic acids under ambient conditions. Understanding the fundamentals of this new chemical process provides a possible protocol to solve global plastic-waste problems. PMID:27168079

  15. Interaction of functional NPC1 gene Polymorphism with smoking on coronary heart disease

    Hui Rutai

    2010-10-01

    Full Text Available Abstract Background The protein of Niemann-pick type C1 gene (NPC1 is known to facilitate the egress of cholesterol and other lipids from late endosomes and lysosomes to other cellular compartments. This study aims to investigate whether the genetic variation in NPC1 is associated with risk of coronary heart disease (CHD and to detect whether NPC1 might interact with smoking on the risk of CHD. Methods We performed a case-control study, including 873 patients with coronary heart disease (CHD and 864 subjects without CHD as control. Polymorphisms of NPC1 gene were genotyped by polymerase chain reaction (PCR -restriction fragment length polymorphism (RFLP. Results A tag-SNP rs1805081 (+644A > G in NPC1 was identified. The G allele of the +644 locus showed reduced risk of CHD than wild-type genotype in Chinese population (recessive model GG vs. AG+AA: odds ratio [OR] 0.647, 95% CI 0.428 to 0.980, P = 0.039; additive model GG vs. AG vs. AA: OR 0.847, 95% CI 0.718 to 0.998, P = 0.0471. Moreover in smokers, the G-allele carriers had reduced risk of CHD compared with A-allele carries (OR 0.552, 95% CI 0.311 to 0.979, P = 0.0421. Conclusions The results of the present study suggest that NPC1 variants seem to be contributors to coronary heart disease occurrence in Chinese population. Moreover, in smokers, NPC1 variants seem to confer protection to coronary heart disease.

  16. Photovoltaic power converter system with a controller configured to actively compensate load harmonics

    de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

    2008-12-16

    Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

  17. Decreased NPC1L1 expression in the liver from Chinese female gallstone patients

    Zhang Sheng-Dao

    2010-02-01

    Full Text Available Abstract Background Cholesterol gallstone disease is a very common disease in both industrialized and developing countries. Many studies have found that cholesterol gallstones are more common in women than men. The molecular mechanisms underlying the relationship between female gallstone disease and hepatic sterol transporters are still undergoing definition and have not been evaluated in humans. Aims The aim of this study is to probe for underlying hepatic molecular defects associated with development of gallstones in female. Methods/Results Fifty-seven nonobese, normolipidemic Chinese female gallstone patients (GS were investigated with 12 age- and body mass index-matched female gallstone-free controls (GSF. The bile from the female GS had higher cholesterol saturation than that from the female GSF. The hepatic NPC1L1 mRNA levels were lower in female GS, correlated with SREBP2 mRNA. NPC1L1 downregulation was confirmed at protein levels. Consistently, immunohistochemistry showed decreased NPC1L1 expression in female GS. Conclusions The decreased hepatic NPC1L1 levels in female GS might indicate a downregulated reabsorption of biliary cholesterol in the liver, which, in turn, leads to the cholesterol supersaturation of bile. Our data are consistent with the possibility that hepatic NPC1L1 may be mediated by SREBP2.

  18. Angiotensin-I-Converting Enzyme Inhibitory and Antioxidant Activities of Protein Hydrolysate from Muscle of Barbel (Barbus callensis

    Assaad Sila

    2013-01-01

    Full Text Available The present study investigated angiotensin-I-converting enzyme (ACE inhibitory and antioxidant activities of barbel muscle protein hydrolysate prepared with Alcalase. The barbel muscle protein hydrolysate displayed a high ACE inhibitory activity (CI50=0.92 mg/mL. The antioxidant activities of protein hydrolysate at different concentrations were evaluated using various in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH radical method and reducing power assay. The barbel muscle protein hydrolysate exhibited an important radical scavenging effect and reducing power. These results obtained by in vitro systems obviously established the antioxidant potency of barbel hydrolysate to donate electron or hydrogen atom to reduce the free radical. Furthermore, these bioactive substances can be exploited into functional foods or used as source of nutraceuticals.

  19. Molecular Descriptors in Modelling the Tumour Necrosis Factor-α Converting Enzyme Inhibition Activity of Novel Tartrate-Based Analogues

    P Singh

    2013-01-01

    Full Text Available The tumour necrosis factor-α converting enzyme inhibition activity of a series comprising of novel tartrate-based analogues has been quantitatively analysed in terms of molecular descriptors. The statistically validated quantitative structure-activity relationship models provided rationales to explain the inhibition activity of these congeners. The descriptors identified through combinatorial protocol in multiple linear regression analysis have highlighted the role of Moran autocorrelation of lag 7, weighted by atomic van der Waals volume, presence of both prime and nonprime amide carbonyl oxygen in the tartrate moiety and occurrence of five membered ring bearing substituents at varying sites. A few potential novel tartrate-based analogues have been suggested for further investigation.

  20. Grid-Current-Feedback Active Damping for LCL Resonance in Grid-Connected Voltage-Source Converters

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2016-01-01

    adding a virtual impedance across the grid-side inductance. This added impedance is more precisely represented by a series RL branch in parallel with a negative inductance. The negative inductance helps to mitigate phase lag caused by time delays found in a digitally controlled system. The mitigation of......This paper investigates active damping of LCL-filter resonance in a grid-connected voltage-source converter with only grid-current feedback control. Basic analysis in the s-domain shows that the proposed damping technique with a negative high-pass filter along its damping path is equivalent to...... phase-lag, in turn, helps to shrink the region of nonminimum-phase behavior caused by negative virtual resistance inserted unintentionally by most digitally implemented active damping techniques. The presented high-pass-filtered active damping technique with a single grid-current feedback loop is thus a...

  1. Analysis and design of grid-current-feedback active damping for LCL resonance in grid-connected voltage source converters

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    This paper investigates the active damping of LCL-filter resonance within single-loop grid current control of grid-connected voltage source converters. First, the basic analysis in the continuous s-domain reveals that the grid-current-feedback active damping forms a virtual impedance across the...... grid-side inductor, and the use of a high-pass filter with a negative sign shapes the virtual impedance by an RL damper paralleled by a negative inductance. It is further found that such a negative virtual inductance plays a critical role in mitigating the phase lag caused by the time delay in a...... digital control system. The instability induced by the negative virtual resistance, which is commonly experienced in the feedback-type active damping, can thus be avoided. A systematic design method of the highpass filter is also proposed by the help of root locus analysis in the discrete z-domain. Lastly...

  2. Structural Insights into the Niemann-Pick C1 (NPC1)-Mediated Cholesterol Transfer and Ebola Infection.

    Gong, Xin; Qian, Hongwu; Zhou, Xinhui; Wu, Jianping; Wan, Tao; Cao, Pingping; Huang, Weiyun; Zhao, Xin; Wang, Xudong; Wang, Peiyi; Shi, Yi; Gao, George F; Zhou, Qiang; Yan, Nieng

    2016-06-01

    Niemann-Pick disease type C (NPC) is associated with mutations in NPC1 and NPC2, whose gene products are key players in the endosomal/lysosomal egress of low-density lipoprotein-derived cholesterol. NPC1 is also the intracellular receptor for Ebola virus (EBOV). Here, we present a 4.4 Å structure of full-length human NPC1 and a low-resolution reconstruction of NPC1 in complex with the cleaved glycoprotein (GPcl) of EBOV, both determined by single-particle electron cryomicroscopy. NPC1 contains 13 transmembrane segments (TMs) and three distinct lumenal domains A (also designated NTD), C, and I. TMs 2-13 exhibit a typical resistance-nodulation-cell division fold, among which TMs 3-7 constitute the sterol-sensing domain conserved in several proteins involved in cholesterol metabolism and signaling. A trimeric EBOV-GPcl binds to one NPC1 monomer through the domain C. Our structural and biochemical characterizations provide an important framework for mechanistic understanding of NPC1-mediated intracellular cholesterol trafficking and Ebola virus infection. PMID:27238017

  3. A high voltage DC-DC converter driving a Dielectric Electro Active Polymer actuator for wind turbine flaps

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.; Thomsen, Ole Cornelius

    2012-01-01

    The Dielectric Electro Active Polymer (DEAP) material is a very thin (~80 μm) silicone elastomer film with a compliant metallic electrode layer on both sides. The DEAP is fundamentally a capacitor that is capable of very high strain. The property that the polymer changes its shape, as a result of...... topology to obtain high voltage at low current, for driving the DEAP actuator. Simulation and experimental results for uni-directional flyback converter topology are shown....... flaps. With the DEAP based high power actuator, it is expected to make a reliable and light solution with superior controllability. The current DEAP technology requires high DC voltage in the range of kV to fully utilize the DEAP material as an actuator. In this paper we propose a flyback converter......The Dielectric Electro Active Polymer (DEAP) material is a very thin (~80 μm) silicone elastomer film with a compliant metallic electrode layer on both sides. The DEAP is fundamentally a capacitor that is capable of very high strain. The property that the polymer changes its shape, as a result of...

  4. SOGI-based capacitor voltage feedback active damping in LCL-filtered grid converters

    Xin, Zhen; Wang, Xiongfei; Loh, Poh Chiang;

    2015-01-01

    The capacitor voltage feedback active damping control is an attractive way to suppress LCL-filter resonance especially for the systems where the capacitor voltage is used for grid synchronization, since no extra sensors are added. The derivative is the core of the capacitor voltage feedback active...... derivative is more suited for capacitor voltage feedback active damping control. Experimental results validate the effectiveness of the proposed method....

  5. Control and dynamic analysis of a parallel-connected single active bridge DC-DC converter for DC-grid wind farm application

    Park, Kiwoo; Chen, Zhe

    2015-01-01

    have several advantages for high-power applications, and the modular concept of the parallel-connected converter is highly beneficial especially for offshore wind farm applications in terms of maintenance cost and fault tolerance. To justify the feasibility of the parallel-connected SAB dc-dc converter......This study presents a control strategy and its dynamic analysis of a high-power dc-dc converter, which is constructed with the parallel-connected single active bridge (SAB) dc-dc converters for dc-grid wind farm applications. The structural and operational characteristics of the SAB dc-dc converter...... for dc-grid wind farm applications, an input voltage control method based on the PI control will be introduced and the dynamics of the overall system will be analysed. The analysis results are to be verified by means of simulations and experiments....

  6. Synthesis and evaluation of radioiodinated NPC 22009, a putative CRF receptor antagonist

    Several studies have suggested that corticotropin-releasing factor (CRF) plays a role in stress-related disorders such as anxiety, depression, anorexia nervosa and stress-induced immune suppression. Hence CRF antagonists have potential therapeutic utility. Recently the authors discovered that pyrazolones such as NPC 22009 and the corresponding disulfide behave as CRF antagonists in vitro with micromolar potency. To probe the nature of this CRF antagonism they developed a convenient synthesis of radioiodinated NPC 22009. Details of the synthesis and preliminary pharmacological studies are presented

  7. Deep Cryogenic Low Power 24 Bits Analog to Digital Converter with Active Reverse Cryostat

    Turqueti, Marcos; Prestemon, Soren; Albright, Robert

    LBNL is developing an innovative data acquisition module for superconductive magnets where the front-end electronics and digitizer resides inside the cryostat. This electronic package allows conventional electronic technologies such as enhanced metal-oxide-semiconductor to work inside cryostats at temperatures as low as 4.2 K. This is achieved by careful management of heat inside the module that keeps the electronic envelop at approximately 85 K. This approach avoids all the difficulties that arise from changes in carrier mobility that occur in semiconductors at deep cryogenic temperatures. There are several advantages in utilizing this system. A significant reduction in electrical noise from signals captured inside the cryostat occurs due to the low temperature that the electronics is immersed in, reducing the thermal noise. The shorter distance that signals are transmitted before digitalization reduces pickup and cross-talk between channels. This improved performance in signal-to-noise rate by itself is a significant advantage. Another important advantage is the simplification of the feedthrough interface on the cryostat head. Data coming out of the cryostat is digital and serial, dramatically reducing the number of lines going through the cryostat feedthrough interface. It is important to notice that all lines coming out of the cryostat are digital and low voltage, reducing the possibility of electric breakdown inside the cryostat. This paper will explain in details the architecture and inner workings of this data acquisition system. It will also provide the performance of the analog to digital converter when the system is immersed in liquid helium, and in liquid nitrogen. Parameters such as power dissipation, integral non-linearity, effective number of bits, signal-to-noise and distortion, will be presented for both temperatures.

  8. Comparison of the Effects of Matrix Metalloproteinase Inhibitors on TNF-α Release from Activated Microglia and TNF-α Converting Enzyme Activity

    Lee, Eun-Jung; Moon, Pyong-Gon; Baek, Moon-Chang; Kim, Hee-Sun

    2014-01-01

    Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that regulate cell-matrix composition and are also involved in processing various bioactive molecules such as cell-surface receptors, chemokines, and cytokines. Our group recently reported that MMP-3, -8, and -9 are upregulated during microglial activation and play a role as proinflammatory mediators (Lee et al., 2010, 2014). In particular, we demonstrated that MMP-8 has tumor necrosis factor alpha (TNF-α)-converting enzyme (T...

  9. Accurate and Less-Disturbing Active Antiislanding Method Based on PLL for Grid-Connected Converters

    Ciobotaru, Mihai; Agelidis, Vassilios G.; Teodorescu, Remus;

    2010-01-01

    caused by this method is small compared to other active antiislanding methods, such as active frequency drift or frequency shift up/down. The method does not affect the zero crossing of the injected current, can be used to estimate the grid impedance, and is highly robust to different grid disturbances...

  10. Coherent combining of fiber-laser-pumped frequency converters using all fiber electro-optic modulator for active phase control

    Bourdon, P.; Durécu, A.; Canat, G.; Le Gouët, J.; Goular, D.; Lombard, L.

    2015-03-01

    Coherent beam combining (CBC) by active phase control could be useful for power scaling fiber-laser-pumped optical frequency converters like OPOs. However, a phase modulator operating at the frequency-converted wavelength is needed, which is non standard component. Fortunately, nonlinear conversion processes rely on a phase-matching condition correlating, not only the wave vectors of the coupled waves, but also their phases. This paper demonstrates that, using this phase correlation for indirect control of the phase, coherent combining of optical frequency converters is feasible using standard all-fibered electro-optic modulators. For the sake of demonstration, this new technique is experimentally applied twice for continuous wave second-harmonic-generator (SHG) combination: i) combining 2 SHG of 1.55-μm erbium-doped fiber amplifiers in PPLN crystals generating 775-nm beams; ii) combining 2 SHG of 1.064-μm ytterbium-doped fiber amplifiers in LBO crystals generating 532-nm beams. Excellent CBC efficiency is achieved on the harmonic waves in both these experiments, with λ/20 and λ/30 residual phase error respectively. In the second experiment, I/Q phase detection is added on fundamental and harmonic waves to measure their phase variations simultaneously. These measurements confirm the theoretical expectations and formulae of correlation between the phases of the fundamental and harmonic waves. Unexpectedly, in both experiments, when harmonic waves are phase-locked, a residual phase difference remains between the fundamen tal waves. Measurements of the spectrum of these residual phase differences locate them above 50 Hz, revealing that they most probably originate in fast-varying optical path differences induced by turbulence and acoustic-waves on the experimental breadboard.

  11. Speed Control Of Separately Excited Dc Motor Using A High Efficiency Flyback Converter With New Active Clamp Technique M.Subramanyam*, K.Eswaramma

    M.Subramanyam

    2014-10-01

    Full Text Available This paper deals with Speed control of separately excited DC motor using flyback converter with a new non complementary active clamp control method to achieve soft switching and high efficiency for heavy motor load and light load conditions. This is quite attractive for low power application with universal ac inputs, such as external adaptors. With the proposed control technique, the energy in the leakage inductance can be fully recycled. The soft switching can be achieved for the main switch and the absorbed leakage energy is transferred to the output and input side. In the Proposed model the resistive and DC motor is connected to flyback converter and it is simulated with different nominal voltages and rated speed is controlled at different levels for the N-type active clamp flyback converter and P-type active clamp flyback converter respectively. N-type active clamp flyback converter is suitable for high speed variation applications and P-type active clamp flyback converter is suitable for low speed variation applications.

  12. Characterization of Niemann-Pick Type C2 protein expression in multiple cancers using a novel NPC2 monoclonal antibody.

    Yi-Jen Liao

    Full Text Available Niemann-Pick Type C2 (NPC2 plays an important role in the regulation of intracellular cholesterol homeostasis via direct binding with free cholesterol. However, little is known about the significance of NPC2 in cancer. In this study, we have pinpointed the impact of various different cancers on NPC2 expression. A series of anti-NPC2 monoclonal antibodies (mAbs with the IgG2a isotype were generated and peptide screening demonstrated that the reactive epitope were amino acid residues 31-40 of the human NPC2 protein. The specificity of these mAbs was confirmed by Western blotting using shRNA mediated knock-down of NPC2 in human SK-Hep1 cells. By immunohistochemical staining, NPC2 is expressed in normal kidney, liver, breast, colon, lung, esophageal, uterine cervical, pancreatic and stomach tissue. Strong expression of NPC2 was found in the distal and proximal convoluted tubule of kidney and the hepatocytes of liver. Normal esophageal, uterine cervical, pancreatic, stomach, breast, colon and lung tissue stained moderately to weakly. When compared to their normal tissue equivalents, NPC2 overexpression was observed in cancers of the breast, colon and lung. Regarding to breast cancer, NPC2 up-regulation is associated with estrogen receptor (-, progesterone receptor (- and human epidermal growth factor receptor (+. On the other hand, NPC2 was found to be down-regulated in renal cell carcinoma, liver cirrhosis and hepatoma tissues. By antigen-capture enzyme immunoassay ELISA, the serum NPC2 is increased in patients with cirrhosis and liver cancer. According to western blot data, the change of glycosylated pattern of NPC2 in serum is associated with cirrhosis and liver cancer. To the best of our knowledge, this is the first comprehensive immunohistochemical and serological study investigating the expression of NPC2 in a variety of different human cancers. These novel monoclonal antibodies should help with elucidating the roles of NPC2 in tumor

  13. Structural Basis of Sterol Binding by NPC2, a Lysosomal Protein Deficient in Niemann-Pick Type C2 Disease

    Xu,S.; Benoff, B.; Liou, H.; Lobel, P.; Stock, A.

    2007-01-01

    NPC2 is a small lysosomal glycoprotein that binds cholesterol with submicromolar affinity. Deficiency in NPC2 is the cause of Niemann-Pick type C2 disease, a fatal neurovisceral disorder characterized by accumulation of cholesterol in lysosomes. Here we report the crystal structure of bovine NPC2 bound to cholesterol-3-O-sulfate, an analog that binds with greater apparent affinity than cholesterol. Structures of both apo-bound and sterol-bound NPC2 were observed within the same crystal lattice, with an asymmetric unit containing one molecule of apoNPC2 and two molecules of sterol-bound NPC2. As predicted from a previously determined structure of apoNPC2, the sterol binds in a deep hydrophobic pocket sandwiched between the two {beta}-sheets of NPC2, with only the sulfate substituent of the ligand exposed to solvent. In the two available structures of apoNPC2, the incipient ligand-binding pocket, which ranges from a loosely packed hydrophobic core to a small tunnel, is too small to accommodate cholesterol. In the presence of sterol, the pocket expands, facilitated by a slight separation of the {beta}-strands and substantial reorientation of some side chains, resulting in a perfect molding of the pocket around the hydrocarbon portion of cholesterol. A notable feature is the repositioning of two aromatic residues at the tunnel entrance that are essential for NPC2 function. The NPC2 structures provide evidence of a malleable binding site, consistent with the previously documented broad range of sterol ligand specificity.

  14. Digital Realization of Capacitor-Voltage Feedback Active Damping for LCL-Filtered Grid Converters

    Xin, Zhen; Wang, Xiongfei; Loh, Poh Chiang;

    2015-01-01

    The capacitor voltage of an LCL-filter can also be used for active damping, if it is fed back for synchronization. By this way, an extra current sensor can be avoided. Compared with the existing active damping techniques designed with capacitor current feedback, the capacitor voltage feedback...... overcome their drawbacks, a new derivative method is then proposed, based on the non-ideal generalized integrator. The performance of the proposed derivative has been found to match the ideal “s” function closely. Active damping based on capacitor voltage feedback can therefore be realized accurately, as...

  15. Highly Accurate Derivatives for LCL-Filtered Grid Converter with Capacitor Voltage Active Damping

    Xin, Zhen; Loh, Poh Chiang; Wang, Xiongfei;

    2016-01-01

    The middle capacitor voltage of an LCL-filter, if fed back for synchronization, can be used for active damping. An extra sensor for measuring the capacitor current is then avoided. Relating the capacitor voltage to existing popular damping techniques designed with capacitor current feedback would...... then proposed, based on either second-order or non-ideal generalized integrator. Performances of these derivatives have been found to match the ideal “s” function closely. Active damping based on capacitor voltage feedback can therefore be realized accurately. Experimental results presented have...

  16. Convergent evidences from human and animal studies implicate angiotensin I-converting enzyme activity in cognitive performance in schizophrenia.

    Gadelha, A; Vendramini, A M; Yonamine, C M; Nering, M; Berberian, A; Suiama, M A; Oliveira, V; Lima-Landman, M T; Breen, G; Bressan, R A; Abílio, V; Hayashi, M A F

    2015-01-01

    In schizophrenia (SCZ), higher angiotensin I-converting enzyme (ACE) levels have been reported in patient's blood and cerebrospinal fluid (CSF). Hereby, we propose to explore whether the ACE activity levels are associated to cognitive performance in SCZ. Seventy-two patients with SCZ or schizoaffective disorder diagnosis, and 69 healthy controls (HCs) underwent a cognitive battery with parallel collection of peripheral blood samples to measure ACE activity. Significant higher ACE activity levels were confirmed in the plasma of SCZ patients compared with HCs (Student's t=-5.216; Pmodel was 0.343. This result was evident only comparing extreme groups for ACE activity, when splitting the sample in three groups with similar number of subjects. To clarify this finding, we performed an evaluation of the cognitive performance of transgenic mice with three copies of ACE gene in novel object recognition (NOR) test, which showed that such animals presented impairment in NOR (Panimals. The results observed in SCZ patients and animal model suggest both the association of ACE to cognitive deficits in SCZ. This finding may support the evaluation of novel treatment protocols and/or of innovative drugs for specific intervention of cognitive deficits in SCZ envisioning concomitant ACE activity and behavior evaluations. PMID:26645626

  17. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    It has been suggested that cholesterol may modulate amyloid-β (Aβ) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD (β-amyloid precursor protein (APP), β-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/Aβ formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1-/- cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, γ-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards Aβ occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  18. Open-circuit fault diagnosis for a grid-connected NPC inverter with unity Power Factor

    Choi, Uimin; Blaabjerg, Frede; Lee, June-Seok;

    2015-01-01

    This paper presents an open-circuit fault detection method for a grid-connected Neutral-Point Clamped (NPC) inverter. The open-circuit fault mainly occurs due to bonding wire failures like lift-off and crack in the power module where the thermal stress is major factor among the stresses that can ...

  19. National Renewable Energy Laboratory Pyrheliometer Comparisons: 24 September - 5 October 2012 (NPC-2012)

    Stoffel, T.; Reda, I.

    2013-05-01

    The NREL Pyrheliometer Comparisons for 2012 (NPC-2012) were held at the Solar Radiation Research Laboratory in Golden, Colorado, from September 24 through October 5 for the purpose of transferring the World Radiometric Reference (WRR) to participating instrument. Twenty scientists and engineers operated 32 absolute cavity radiometers and 18 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky direct normal irradiance during the comparisons. The transfer standard group of reference radiometers for NPC-2012 consisted of four NREL radiometers with direct traceability to the WRR, having participated in the Eleventh International Pyrheliometer Comparisons (IPC-XI) hosted by the World Radiation Center in the fall of 2010. As the result of NPC-2012, each participating absolute cavity radiometer was assigned a new WRR transfer factor, computed as the reference irradiance computed by the transfer standard group divided by the observed irradiance from the participating radiometer. The performance of the transfer standard group during NPC-2012 was consistent with previous comparisons, including IPC-XI. The measurement performance of the transfer standard group allowed the transfer of the WRR to each participating radiometer with an estimated uncertainty of +/- 0.33% with respect to the International System of Units.

  20. Genetic variation in the cholesterol transporter NPC1L1, ischaemic vascular disease, and gallstone disease

    Lauridsen, Bo Kobberø; Stender, Stefan; Frikke-Schmidt, Ruth;

    2015-01-01

    AIMS: Ezetimibe reduces plasma levels of low-density lipoprotein (LDL) cholesterol by inhibiting Niemann-Pick C1-Like protein 1 (NPC1L1), the transporter responsible for cholesterol uptake from the intestine into enterocytes and from the bile into hepatocytes. We tested the hypothesis that geneti...

  1. Active Power and DC-link Voltage Coordinative Control for Cascaded DC-AC Converter with Bidirectional Power Application

    Tian, Yanjun; Chen, Zhe; Deng, Fujin;

    2015-01-01

    Two stage cascaded converters are widely used in DC/AC hybrid systems to achieve the bidirectional power transmission. The topology of dual active bridge cascaded with inverter (DABCI) is commonly used in this application. This paper proposes a coordinative control method for DABCI and it’s able to...... reduce the DC-link voltage fluctuation between the DAB and inverter, then reduce the stress on the switching devices, as well as improve the system dynamic performance. In the proposed control method, the DAB and inverter are coordinated to control the DC-link voltage and the power, and this...... responsibility sharing control can effectively suppress the impact of the power variation on the DC-link voltage, without sacrificing stability. The proposed control method is also effective for DABCI in unidirectional power transmission. The effectiveness of the propose control has been validated by both...

  2. Contribution to the Active Generator Principle: the Gate-commutated Polyphased Matrix Converter

    Béguin, Antoine

    2012-01-01

    This work is part of the innovative "Active Generator" (AG) project. AG is a concept that suggests a new arrangement of the turbine-generator line of a high power utility (a few hundred of MW) in order to de-synchronize the rotation speed of the turbine-generator group from the fixed grid frequency (50 Hz or 60 Hz). This de-synchronization has essentially two advantages. First, the variable speed of the group enables the operation of the turbine...

  3. Converting poultry litter to activated carbon: optimal carbonization conditions and product sorption for benzene.

    Guo, Mingxin; Song, Weiping

    2011-12-01

    To promote utilization of poultry litter as a source material for manufacturing low-cost activated carbon (AC) that can be used in wastewater treatment, this study investigated optimal production conditions and water-borne organic sorption potential of poultry litter-based AC. Pelletized broiler litter was carbonized at different temperatures for varied time periods and activated with steam at a range of flow rate and time. The AC products were examined for quality characteristics using standard methods and for organic sorption potentials using batch benzene sorption techniques. The study shows that the yield and quality of litter AC varied with production conditions. The optimal production conditions for poultry litter-based AC were carbonization at 700 degrees C for 45 min followed by activation with 2.5 ml min(-1) steam for another 45 min. The resulting AC possessed an iodine number of 454 mg g(-1) and a specific surface area of 403 m2 g(-1). It sorbed benzene in water following sigmoidal kinetic and isothermal patterns. The sorption capacity for benzene was 23.70 mg g(-1), lower than that of top-class commercial AC. The results, together with other reported research findings, suggest that poultry litter is a reasonable feedstock for low-cost AC applicable to pre-treat wastewater contaminated by organic pollutants and heavy metals. PMID:22439566

  4. Effect of Antiviral Therapy on Serum Activity of Angiotensin Converting Enzyme in Patients with Chronic Hepatitis C

    Husic-Selimovic, Azra; Sofic, Amela; Huskic, Jasminko; Bulja, Deniz

    2016-01-01

    Introduction: Renin-angiotenzin system (RAS) is frequently activated in patients with chronic liver disease. Angiotenzin - II (AT-II), produced by angiotenzin converting enzyme (ACE), has many physiological effects, including an important role in liver fibrogenesis. Combined antiviral therapy with PEG-IFN and ribavirin besides its antiviral effect also leads to a reduction in liver parenchyma fibrosis. Aim of the study: Determining the value of ACE in serum of patients with chronic hepatitis C before and after combined antiviral therapy, as well as the value of ACE activities in sera of the control group. Materials and methods: We studied 50 patients treated at Gastroenterohepatology Department, in the time-period of four years. Value of ACE in serum was determined by Olympus AU 400 device, with application of kit “Infinity TN ACE Liquid Stable Reagent”. HCV RNA levels in sera were measured by real time PCR. HCV RNA test was performed with modular analysis of AMPLICOR and COBAS AMPLICOR HCV MONITOR test v2.0, which has proved infection and was used for quantification of the viruses and monitoring of the patients’ response to therapy. Liver histology was evaluated in accordance with the level of necroinflammation activity and stage of fibrosis. Results: Serum activities of ACE in chronic hepatitis C patients is statistically higher than the values in the control group (p=0.02). Antiviral therapy in chronic hepatitis C patients statistically decreases serum activities of ACE (p= 0.02) and indirectly affects fibrogenesis of the liver parenchyma. Correlation between ACE and ALT activity after the therapy was proved (0.3934). Conclusion: Our findings suggest that the activity of ACE in serum is a good indirect parameter of the liver damage, and could be used as an indirect prognostic factor of the level of liver parenchyma damage. Serum activity of ACE can be used as a parameter for non-invasive assessment of intensity of liver damage. PMID:27147779

  5. Enhanced Stability of Capacitor-Current Feedback Active Damping for LCL-Filtered Grid Converters

    Xin, Zhen; Wang, Xiongfei; Loh, Poh Chiang;

    2015-01-01

    The proportional capacitor-current feedback active damping method has been widely used to suppress the LCL-filter resonance. However, the time delay in the damping control loop may lead to non-minimum phase or even unstable responses when the resonance frequency varies in a wide range. To improve...... the robustness of damping, this paper proposes an improved damping controller with the capacitor current feedback loop, which is based on the second-order generalized integrator, instead of a proportional gain, which can effectively mitigate the detrimental effect of the time delay. Robustness of the...

  6. High-performance feedback-type active damping of LCL-filtered voltage source converters

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    generalized impedance-based model of grid current control with feedback-type active damping. Then, a controller design method based on the z-domain root contours and frequency-domain passivity theorem is proposed. It not only allows a co-design of the grid current controller and damping controller, but...... ensures also a robust stabilization against the grid parameters variations. For illustration, the approach is applied to design three single-state feedback-damping schemes, and their damping robustness are compared under both inductive and resonant grid impedances. Experimental results validate the...

  7. Sterol transfer between cyclodextrin and membranes: similar but not identical mechanism to NPC2-mediated cholesterol transfer.

    McCauliff, Leslie A; Xu, Zhi; Storch, Judith

    2011-08-30

    Niemann--Pick C disease is an inherited disorder in which cholesterol and other lipids accumulate in the late endosomal/lysosomal compartment. Recently, cyclodextrins (CD) have been shown to reduce symptoms and extend lifespan in animal models of the disease. In the present studies we examined the mechanism of sterol transport by CD using in vitro model systems and fluorescence spectroscopy and NPC2-deficient fibroblasts. We demonstrate that cholesterol transport from the lysosomal cholesterol-binding protein NPC2 to CD occurs via aqueous diffusional transfer and is very slow; the rate-limiting step appears to be dissociation of cholesterol from NPC2, suggesting that specific interactions between NPC2 and CD do not occur. In contrast, the transfer rate of the fluorescent cholesterol analogue dehydroergosterol (DHE) from CD to phospholipid membranes is very rapid and is directly proportional to the acceptor membrane concentration, as is DHE transfer from membranes to CD. Moreover, CD dramatically increases the rate of sterol transfer between membranes, with rates that can approach those mediated by NPC2. The results suggest that sterol transfer from CD to membranes occurs by a collisional transfer mechanism involving direct interaction of CD with membranes, similar to that shown previously for NPC2. For CD, however, absolute rates are slower compared to NPC2 for a given concentration, and the lysosomal phospholipid lysobisphosphatidic acid (LBPA) does not stimulate rates of sterol transfer between membranes and CD. As expected from the apparent absence of interaction between CD and NPC2, the addition of CD to NPC2-deficient fibroblasts rapidly rescued the cholesterol accumulation phenotype. Thus, the recent observations of CD efficacy in mouse models of NPC disease are likely the result of CD enhancement of cholesterol transport between membranes, with rapid sterol transfer occurring during CD--membrane interactions. PMID:21740003

  8. Antioxidant capacity and angiotensin I converting enzyme inhibitory activity of a melon concentrate rich in superoxide dismutase.

    Carillon, Julie; Del Rio, Daniele; Teissèdre, Pierre-Louis; Cristol, Jean-Paul; Lacan, Dominique; Rouanet, Jean-Max

    2012-12-01

    Antioxidant capacity and angiotensin 1-converting enzyme (ACE) inhibitory activity of a melon concentrate rich in superoxide dismutase (SOD-MC) were investigated in vitro. The total antioxidant capacity (TAC) was measured by the Trolox equivalent antioxidant capacity assay (TEAC), the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay, and the ferric reducing antioxidant power assay (FRAP). The ability of the extract to scavenge three specific reactive oxygen species (superoxide radical anion (O(2)(-)), hydroxyl radical (HO()) and hydrogen peroxide (H(2)O(2))) was also investigated in order to better evaluate its antioxidant properties. Even if the measures of TAC were relatively low, results clearly established an antioxidant potential of SOD-MC that exhibited the highest radical-scavenging activity towards O(2)(-), with a IC(50) 12-fold lower than that of H(2)O(2) or HO(). This lets hypothesis that the antioxidant potential of SOD-MC could be mainly due to its high level of SOD. Moreover, for the first time, an ACE inhibitory activity of SOD-MC (IC(50)=2.4±0.1mg/mL) was demonstrated, showing that its use as a functional food ingredient with potential preventive benefits in the context of hypertension may have important public health implications and should be carefully considered. PMID:22953857

  9. A Tricholoma matsutake Peptide with Angiotensin Converting Enzyme Inhibitory and Antioxidative Activities and Antihypertensive Effects in Spontaneously Hypertensive Rats

    Geng, Xueran; Tian, Guoting; Zhang, Weiwei; Zhao, Yongchang; Zhao, Liyan; Wang, Hexiang; Ng, Tzi Bun

    2016-01-01

    Hypertension is a major risk factor for cardiovascular disease. A crude water extract of the fruiting bodies of a highly prized mushroom Tricholoma matsutakei exerted an antihypertensive action on spontaneously hypertensive rats (SHRs) at a dosage of 400 mg/kg. An angiotensin converting enzyme (ACE) inhibitory peptide with an IC50 of 0.40 μM was purified from the extract and designated as TMP. Its amino acid sequence was elucidated to be WALKGYK through LC-MS/MS analysis. The Lineweaver-Burk plot suggested that TMP was a non-competitive inhibitor of ACE. A short-term assay of antihypertensive activity demonstrated that TMP at the dosage of 25 mg/kg could significantly lower the systolic blood pressure (SBP) of SHRs. TMP exhibited remarkable stability over a wide range of temperatures and pH values. It also demonstrated 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The aforementioned activities of TMP were corroborated by utilizing the synthetic peptide. Hence T. matsutake can be used as a functional food to help prevent hypertension- associated diseases. PMID:27052674

  10. Single stage single phase active power factor corrected Ĉuk Topology Based AC-DC Converter

    Md. Ismail Hossain

    2014-01-01

    This paper focuses on the analysis of a power factor correction (PFC) converter using close loop Ĉuk topology. Regardless of the input line voltage and output load variations, input current drawn by the buck or buck-boost converter is always discontinuous. The Boost converter suffers from high voltage stresses across the power electronic devices. The input current in Ĉuk converter is comparable to boost converter’s input current. In this paper output voltage is controlled by inner cur...

  11. Angiotensin-converting enzyme 2/angiotensin-(1-7)/Mas axis activates Akt signaling to ameliorate hepatic steatosis.

    Cao, Xi; Yang, Fangyuan; Shi, Tingting; Yuan, Mingxia; Xin, Zhong; Xie, Rongrong; Li, Sen; Li, Hongbing; Yang, Jin-Kui

    2016-01-01

    The classical axis of renin-angiotensin system (RAS), angiotensin (Ang)-converting enzyme (ACE)/Ang II/AT1, contributes to the development of non-alcoholic fatty liver disease (NAFLD). However, the role of bypass axis of RAS (Angiotensin-converting enzyme 2 (ACE2)/Ang-(1-7)/Mas) in hepatic steatosis is still unclear. Here we showed that deletion of ACE2 aggravates liver steatosis, which is correlated with the increased expression of hepatic lipogenic genes and the decreased expression of fatty acid oxidation-related genes in the liver of ACE2 knockout (ACE2(-/y)) mice. Meanwhile, oxidative stress and inflammation were also aggravated in ACE2(-/y) mice. On the contrary, overexpression of ACE2 improved fatty liver in db/db mice, and the mRNA levels of fatty acid oxidation-related genes were up-regulated. In vitro, Ang-(1-7)/ACE2 ameliorated hepatic steatosis, oxidative stress and inflammation in free fatty acid (FFA)-induced HepG2 cells, and what's more, Akt inhibitors reduced ACE2-mediated lipid metabolism. Furthermore, ACE2-mediated Akt activation could be attenuated by blockade of ATP/P2 receptor/Calmodulin (CaM) pathway. These results indicated that Ang-(1-7)/ACE2/Mas axis may reduce liver lipid accumulation partly by regulating lipid-metabolizing genes through ATP/P2 receptor/CaM signaling pathway. Our findings support the potential role of ACE2/Ang-(1-7)/Mas axis in prevention and treatment of hepatic lipid metabolism. PMID:26883384

  12. Hydrolysates of sheep cheese whey as a source of bioactive peptides with antioxidant and angiotensin-converting enzyme inhibitory activities.

    Corrêa, Ana Paula Folmer; Daroit, Daniel Joner; Fontoura, Roberta; Meira, Stela Maris Meister; Segalin, Jeferson; Brandelli, Adriano

    2014-11-01

    Enzymatic proteolysis may be employed to release bioactive peptides, which have been investigated for potential benefits from both technological and human health perspectives. In this study, sheep cheese whey (SCW) was hydrolyzed with a protease preparation from Bacillus sp. P7, and the hydrolysates were evaluated for antioxidant and angiotensin I-converting enzyme (ACE)-inhibitory activities. Soluble protein and free amino acids increased during hydrolysis of SCW for up to 4h. Antioxidant activity of hydrolysates, evaluated by the 2,2'azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid radical scavenging method, increased 3.2-fold from 0 h (15.9%) to 6h of hydrolysis (51.3%). Maximum Fe(2+) chelation was reached in 3h hydrolysates, and the reducing power peaked at 1h of hydrolysis, representing 6.2 and 2.1-fold increase, respectively, when compared to that of non-hydrolyzed SCW. ACE inhibition by SCW (12%) was improved through hydrolysis, reaching maximal values (55% inhibition) in 4h, although 42% inhibition was already observed after 1h hydrolysis. The peptide LAFNPTQLEGQCHV, derived from β-lactoglobulin, was identified from 4-h hydrolysates. Such a biotechnological approach might be an interesting strategy for SCW processing, potentially contributing to the management and valorization of this abundant dairy byproduct. PMID:25218972

  13. Hydrogen converters

    The National Atomic Energy Commission of Argentina developed a process of 99Mo production from fission, based on irradiation of uranium aluminide targets with thermal neutrons in the RA-3 reactor of the Ezeiza Atomic Centre. These targets are afterwards dissolved in an alkaline solution, with the consequent liberation of hydrogen as the main gaseous residue. This work deals with the use of a first model of metallic converter and a later prototype of glass converter at laboratory scale, adjusted to the requirements and conditions of the specific redox process. Oxidized copper wires were used, which were reduced to elementary copper at 400 C degrees and then regenerated by oxidation with hot air. Details of the bed structure and the operation conditions are also provided. The equipment required for the assembling in cells is minimal and, taking into account the operation final temperature and the purge with nitrogen, the procedure is totally safe. Finally, the results are extrapolated for the design of a converter to be used in a hot cell. (author)

  14. The implementation in-house dose verification for IMRT and VMAT on breast cancer and NPC cases

    Azzi, A.; Dimitri, F. Y.; Pawiro, S. A.

    2016-03-01

    IMRT and VMAT have been widely implemented on breast cancer and NPC cases. Dose verification was conducted to ensure the comparison between dose delivered and prescribe dose in TPS to obtain optimal results and the dose delivered. The gafchromic films measurement was done for breast and NPC simulation on RANDO Phantom, irradiating film by 6 MV photon with 200 cGy and scanned with EPSON V700 using 72 dpi. Dose distribution was calculated using the MATLAB-based in-house algorithm. In order to evaluate the gamma index, gafchromic films and MatriXX 2D array were placed in the Multi Cube and irradiated with EPID in same position. Dose distribution differences for IMRT and VMAT with modalities to TPS on film was 5.34% and 6.68% for NPC PTV70; 12.81% and 6.15% for NPC PTV50; 11.14% and 10.80% for breast cancer. Gamma index differences on IMRT with modalities to MatriXX 2D array and EPID was -0.09% and 5.13% for NPC; 0.51% and 2.28% for breast cancer. On the other hand, gamma index difference on VMAT was -1.65% and 1.43% for NPC; 0.19% and 4.38% for breast cancer. This measurement method can be used to verify dose for breast cancer and NPC cases in IMRT and VMAT.

  15. Dielectric Electro Active Polymer Incremental Actuator Driven by Multiple High-Voltage Bi-directional DC-DC Converters

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.;

    2013-01-01

    capacitive sub-actuators. It needs to be driven by three high voltage (~2.5 kV) DC-DC converters, to achieve the linear incremental motion. The topology used for this application is a bi-directional flyback DC-DC converter. The control of the incremental actuator involves, implementation of digital...

  16. Activation of angiotensin-converting enzyme 2 (ACE2) attenuates allergic airway inflammation in rat asthma model.

    Dhawale, Vaibhav Shrirang; Amara, Venkateswara Rao; Karpe, Pinakin Arun; Malek, Vajir; Patel, Deep; Tikoo, Kulbhushan

    2016-09-01

    Angiotensin-I converting enzyme (ACE) is positively correlated to asthma, chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS) and is highly expressed in lungs. ACE2, the counteracting enzyme of ACE, was proven to be protective in pulmonary, cardiovascular diseases. In the present study we checked the effect of ACE2 activation in animal model of asthma. Asthma was induced in male wistar rats by sensitization and challenge with ovalbumin and then treated with ACE2 activator, diminazene aceturate (DIZE) for 2weeks. 48h after last allergen challenge, animals were anesthetized, blood, BALF, femoral bone marrow lavage were collected for leucocyte count; trachea for measuring airway responsiveness to carbachol; lungs and heart were isolated for histological studies and western blotting. In our animal model, the characteristic features of asthma such as altered airway responsiveness to carbachol, eosinophilia and neutrophilia were observed. Western blotting revealed the increased pulmonary expression of ACE1, IL-1β, IL-4, NF-κB, BCL2, p-AKT, p-p38 and decreased expression of ACE2 and IκB. DIZE treatment prevented these alterations. Intraalveolar interstitial thickening, inflammatory cell infiltration, interstitial fibrosis, oxidative stress and right ventricular hypertrophy in asthma control animals were also reversed by DIZE treatment. Activation of ACE2 by DIZE conferred protection against asthma as evident from biochemical, functional, histological and molecular parameters. To the best of our knowledge, we report for the first time that activation of ACE2 by DIZE prevents asthma progression by altering AKT, p38, NF-κB and other inflammatory markers. PMID:27343405

  17. Angiotensin-converting enzyme 2 activation protects against pulmonary arterial hypertension through improving early endothelial function and mediating cytokines levels

    LI Gang; XU Yu-lin; LING Feng; LIU Ai-jun; WANG Dong; WANG Qiang; LIU Ying-long

    2012-01-01

    Background Increasing evidences indicate that an activated renin-angiotensin system (RAS) causes an imbalance between the vasoconstrictive and vasodilator mechanisms involving the pulmonary circulation leading to the development of pulmonary arterial hypertension (PAH).Angiotensin-converting enzyme 2 (ACE2),a primary component of the vasoprotective axis in RAS,is recently identified that it has regulatory actions in lung pathophysiology,but the mechanism in these processes is uncertain yet.Methods Severe PAH was induced by monocrotaline injection one week following pneumonectomy in rats.The activation of ACE2 by continuous injection of resorcinolnaphthalein was studied by real time-polymerase chain reaction (RT-PCR),Western blotting and fluorogenic peptide assay.Endothelial functions were evaluated by the response to acetylcholine and cytokines were measured by RT-PCR seven days after monocrotaline injection.The PAH-related hemodynamics and pathological changes were examined at day 21 when severe PAH was completely established.Results Resorcinolnaphthalein caused significant activation of ACE2 in both normal and diseased rats in 7 days after treatment.The pulmonary arterial pressure (PAP) started to increase at least 7 days after monocrotaline injection,and the rats developed severe PAH in 21 days with high PAP,right ventricular hypertrophy and neointimal formation.Treatment with resorcinolnaphthalein prevented these features.Resorcinolnaphthalein caused an improved endothelia-dependent vasorelaxation and decrease in proinflammatory cytokines (tumor necrosis factor (TNF)-α,monocyte chemoattractant protein-1 (MCP-1),interleukin (IL)-6) and increase in anti-inflammatory cytokine IL-10 in the early stage of the pathogenesis.Conclusions These results demonstrated that activation of ACE2 by continuous injection of resorcinolnaphthalein prevented the development of PAH through improving early endothelial dysfunction and mediating the level of proinflammatory and anti

  18. Optimization of SiC-based H5 and conergy-NPC transformerless PV inverters

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2015-01-01

    frequency and structure of the output filter (either LCL- or LLCL-type) in transformerless H5 and conergy-neutral point clamped (Conergy-NPC) PV inverters, which employ SiC-type power devices. The design results demonstrate that the optimized SiC-based H5 and Conergy-NPC transformerless PV inverters are......The transformerless dc/ac inverters are critical components in the rapidly growing market of grid-connected photovoltaic (PV) applications. They are synthesized by combining available solutions in terms of the power-section topology, power-semiconductors manufacturing technology, and structure of...... more effective in terms of energy production than their nonoptimized and silicon (Si)-based counterparts. In addition, by reducing the market price of SiC-type power semiconductors to the level of Si-based power devices, enables the development of optimized SiC-based PV inverters with a lower cost of...

  19. Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

    E.M. Oliveira

    2000-07-01

    Full Text Available The tripeptide Hip-His-Leu was used to standardize a fluorimetric method to measure tissue angiotensin-converting enzyme (ACE activity in rats. The fluorescence of the o-phthaldialdehyde-His-Leu adduct was compared in the presence and absence of the homogenate (25 µl to determine whether the homogenate from different tissues interfered with the fluorimetric determination of the His-Leu product. Only homogenates from lung and renal medulla and cortex showed significantly altered fluorescence intensity. To overcome this problem, the homogenate from these tissues were diluted 10 times with assay buffer. The specificity of the assay was demonstrated by the inhibition of ACE activity with 3 µM enalaprilat (MK-422. There was a linear relationship between product formation and incubation time for up to 90 min for homogenates of renal cortex and medulla and liver, for up to 60 min for ventricles and adrenals and for up to 30 min for the aorta, lung and atrium homogenates. In addition, there was a linear relationship between product formation and the amount of protein in the homogenates within the following range: lung, 30-600 µg; renal cortex and medulla, 40-400 µg; atrium and ventricles, 20-200 µg; adrenal, 20-100 µg; aorta, 5-100 µg; liver, 5-25 µg. No peptidase activity against the His-Leu product (31 nmol, assayed in borate buffer (BB, was detected in the different homogenates except the liver homogenate, which was inhibited by 0.1 mM r-chloromercuribenzoic acid. ACE activity in BB was higher than in phosphate buffer (PB due, at least in part, to a greater hydrolysis of the His-Leu product in PB. ACE activity of lung increased 20% when BB plus Triton was used. Enzyme activity was stable when the homogenates were stored at -20o or -70oC for at least 30 days. These results indicate a condition whereby ACE activity can be easily and efficiently assayed in rat tissue samples homogenized in BB using a fluorimetric method with Hip-His-Leu as a

  20. Mammalian NPC1 genes may undergo positive selection and human polymorphisms associate with type 2 diabetes

    Al-Daghri Nasser M

    2012-11-01

    Full Text Available Abstract Background The NPC1 gene encodes a protein involved in intracellular lipid trafficking; its second endosomal loop (loop 2 is a receptor for filoviruses. A polymorphism (His215Arg in NPC1 was associated with obesity in Europeans. Adaptations to diet and pathogens represented powerful selective forces; thus, we analyzed the evolutionary history of the gene and exploited this information for the identification of variants/residues of functional importance in human disease. Methods We performed phylogenetic analysis, population genetic tests, and genotype-phenotype analysis in a population from Saudi Arabia. Results Maximum-likelihood ratio tests indicated the action of positive selection on loop 2 and identified three residues as selection targets; these were confirmed by an independent random effects likelihood (REL analysis. No selection signature was detected in present-day human populations, but analysis of nonsynonymous polymorphisms showed that a variant (Ile642Met, rs1788799 in the sterol sensing domain affects a highly conserved position. This variant and the previously described His215Arg polymorphism were tested for association with obesity and type 2 diabetes (T2D in a cohort from Saudi Arabia. Whereas no association with obesity was detected, 642Met allele was found to predispose to T2D. A significant interaction was noted with sex (P = 0.041, and stratification on the basis of gender indicated that the association is driven by men (P = 0.0021, OR = 1.5. Notably, two NPC1 haplotypes were also associated with T2D in men (rs1805081-rs1788799, His-Met: P = 0.0012, OR = 1.54; His-Ile: P = 0.0004, OR = 0.63. Conclusions Our data indicate a sex-specific effect of NPC1 variants on T2D risk and describe putative binding sites for filoviruses entry.

  1. Wavelength Converters

    Kloch, Allan; Hansen, Peter Bukhave; Wolfson, David;

    1999-01-01

    After a short introduction to the different requirements to and techniques for wavelength conversion, focus is on cross-gain and cross-phase modulation in SOAs and SOA based interferometers. Aspects like jitter accumulation, regeneration and conversion to the same wavelength is discussed. It is...... extinction ratio of ~10 dB.The regenerative capabilities of the cross-phase converters are described and verified experimentally at 20 Gbit/s, where the noise redistribution and improvement of the signal-to-noise ratio clearly is demonstrated by controlling the input power to an EDFA. In a similar experiment...

  2. Differential effects of isoproterenol on the activity of angiotensin-converting enzyme in the rat heart and aorta

    Busatto V.C.W.

    1999-01-01

    Full Text Available The excessive stimulation of beta-adrenergic receptors in the heart induces myocardial hypertrophy. There are several experimental data suggesting that this hypertrophy may also depend, at least partially, on the increase of local production of angiotensin II secondary to the activation of the cardiac renin-angiotensin system. In this study we investigated the effects of isoproterenol on the activity of angiotensin-converting enzyme (ACE in the heart and also in the aorta and plasma. Male Wistar rats weighing 250 to 305 g were treated with a dose of (±-isoproterenol (0.3 mg kg-1 day-1, N = 8 sufficient to produce cardiac hypertrophy without deleterious effects on the pumping capacity of the heart. Control rats (N = 7 were treated with vehicle (corn oil. The animals were killed one week later. ACE activity was determined in vitro in the four cardiac chambers, aorta and plasma by a fluorimetric assay. A significant hypertrophy was observed in both ventricular chambers. ACE activity in the atria remained constant after isoproterenol treatment. There was a significant increase (P<0.05 of ACE activity in the right ventricle (6.9 ± 0.9 to 8.2 ± 0.6 nmol His-Leu g-1 min-1 and in the left ventricle (6.4 ± 1.1 to 8.9 ± 0.8 nmol His-Leu g-1 min-1. In the aorta, however, ACE activity decreased (P<0.01 after isoproterenol (41 ± 3 to 27 ± 2 nmol His-Leu g-1 min-1 while it remained unchanged in the plasma. These data suggest that ACE expression in the heart can be increased by stimulation of beta-adrenoceptors. However, this effect is not observed on other local renin-angiotensin systems, such as the aorta. Our data also suggest that the increased sympathetic discharge and the elevated plasma concentration of catecholamines may contribute to the upregulation of ACE expression in the heart after myocardial infarction and heart failure.

  3. N-terminal domain of Bothrops asper Myotoxin II Enhances the Activity of Endothelin Converting Enzyme-1 and Neprilysin

    Smith, A. Ian; Rajapakse, Niwanthi W.; Kleifeld, Oded; Lomonte, Bruno; Sikanyika, Nkumbu L.; Spicer, Alexander J.; Hodgson, Wayne C.; Conroy, Paul J.; Small, David H.; Kaye, David M.; Parkington, Helena C.; Whisstock, James C.; Kuruppu, Sanjaya

    2016-01-01

    Neprilysin (NEP) and endothelin converting enzyme-1 (ECE-1) are two enzymes that degrade amyloid beta in the brain. Currently there are no molecules to stimulate the activity of these enzymes. Here we report, the discovery and characterisation of a peptide referred to as K49-P1-20, from the venom of Bothrops asper which directly enhances the activity of both ECE-1 and NEP. This is evidenced by a 2- and 5-fold increase in the Vmax of ECE-1 and NEP respectively. The K49-P1-20 concentration required to achieve 50% of maximal stimulation (AC50) of ECE-1 and NEP was 1.92 ± 0.07 and 1.33 ± 0.12 μM respectively. Using BLITZ biolayer interferometry we have shown that K49-P1-20 interacts directly with each enzyme. Intrinsic fluorescence of the enzymes change in the presence of K49-P1-20 suggesting a change in conformation. ECE-1 mediated reduction in the level of endogenous soluble amyloid beta 42 in cerebrospinal fluid is significantly higher in the presence of K49-P1-20 (31 ± 4% of initial) compared with enzyme alone (11 ± 5% of initial; N = 8, P = 0.005, unpaired t-test). K49-P1-20 could be an excellent research tool to study mechanism(s) of enzyme stimulation, and a potential novel drug lead in the fight against Alzheimer’s disease. PMID:26931059

  4. A continuous fluorescent assay for the determination of plasma and tissue angiotensin I-converting enzyme activity

    M.F. Alves

    2005-06-01

    Full Text Available A continuous assay using internally quenched fluorescent peptides with the general sequence Abz-peptidyl-(DnpP-OH (Abz = ortho-aminobenzoic acid; Dnp = 2,4-dinitrophenyl was optimized for the measurement of angiotensin I-converting enzyme (ACE in human plasma and rat tissues. Abz-FRK(DnpP-OH, which was cleaved at the Arg-Lys bond by ACE, was used for the enzyme evaluation in human plasma. Enzymatic activity was monitored by continuous recording of the fluorescence (lambdaex = 320 nm and lambdaem = 420 nm at 37ºC, in 0.1 M Tris-HCl buffer, pH 7.0, with 50 mM NaCl and 10 µM ZnCl2. The assays can be performed directly in the cuvette of the fluorimeter and the hydrolysis followed for 5 to 10 min. ACE measurements in the plasma of 80 healthy patients with Hip-His-Leu and with Abz-FRK(DnpP-OH correlated closely (r = 0.90, P < 0.001. The specificity of the assay was demonstrated by the complete inhibition of hydrolysis by 0.5 µM lisinopril or captopril. Abz-FRK(DnpP-OH cleavage by ACE was monitored in rat lung, kidney, heart, and liver homogenates in the presence of a cocktail of inhibitors containing trans-epoxy-succinyl-L-leucylamido-(4-guanido-butene, pepstatin, phenyl-methylsulfonyl fluoride, N-tosyl-L-phenylalanyl-chloromethyl ketone, and N-tosyl-lysyl-chloromethyl ketone to prevent undesirable hydrolysis. ACE activity in lung, heart and kidney homogenates, but not in liver homogenates, was completely abolished by 0.5 µM lisinopril or captopril. The advantages of the method are the procedural simplicity and the high sensitivity providing a rapid assay for ACE determinations.

  5. Enhanced Direct Torque Control for Doubly Fed InductionMachine by Active Learning Method Using Indirect MatrixConverter

    Hamid Behnia

    2012-08-01

    Full Text Available The term Direct Torque Control (DTC originally is referred to a strategy which provides good transient and steady-state performance but it has also some negative aspects, such as non accuracy of flux, torque estimator, torque and flux ripple caused by non-optimality of switching and imprecision in motor model which are known as an inherent characteristic of DTC. This paper explores reducing of flux and torque ripple with using trial and error actively as a method called Active Learning Method (ALM in DTC for Doubly Fed Induction Machine (DFIM which are the motors or generators having twist on both stator and rotor subsequence power is transferred between shaft and system. DFIM is linked to the grid within the stator and the rotor is fed by an Indirect Matrix Converter (IMC. The function of IMC is similar to the direct one, although it has the line and load bridges separated. We analysis the usage of four-step commutation in rectifier stage of IMC to achieve the object of the losses’ reduction which are caused by snubber circuit. ALM adopts itself with torque and flux estimators and estimates the outputs with regards to the errors in torque and flux estimation by repetition therefore achieves the object of omitting inaccuracies in control system hence confirming the effectiveness. Another concept in ALM called Ink Drop Spread (IDS handles different modeling target to predict on the data consequensing a behavior curve in DTC. According to the simulation results, it is proved that a significant torque and stator flux ripple reduction are obtained.

  6. Diagnostic usefulness of bronchoalveolar lavage, Ga scintigraphy and serum angiotensin converting enzyme activity in granulomatous lung disease

    Cellular components of bronchoalveolar lavage (BAL) fluid were studied in 26 sarcoid patients, 8 patients with farmer's lung, 10 healthy controls and 10 control patients. The investigations by Ga scintigraphy or transbronchial lung biopsy (TBLB) and measurement of serum angiotensin converting enzyme (SACE) activity were also carried out in 21 sarcoid patients and 8 patients with farmer's lung. 1) Percentage of foamy cells in alveolar ma crophage fraction, percentage of lymphocytes and number of mast cells were increased significantly in BLA fluid from patients with farmer's lung as compared with that from sarcoid patients. Analysis of cellular component of BAL flu id is useful for differential diagnosis of these diseases. 2) Granulomatous lung lesions were frequently observed in specimens obtained by TBLB from patients with sarcoidosis and farmer's lung who showed abnormal Ga uptake in lung. In contrast, there was no significant difference in percentage of lymphocytes in BAL fluid between patients whose pulmonary Ga uptake was positive and those in whom pulmonary Ga uptake was negative. To investigate the mechanism of pulmonary Ga accumulation in granulomatous lung disease, BAL was performed in 2 sarcoid patients and 3 patients with farmer's lung at 48 to 72 hrs after Ga injection. The radioactivity in cell fractions was evaluated at 96 hrs after Ga injection. Most of the radioactivity was found in macrophages, with little in lymphocytes. Pulmonary Ga uptake in patients with sarcoidosis and farmer' s lung reflects granuloma formation or accumulation of activated macrophages in lung, but not the intensity of T-cell alveolitis. 3) Some relationship among SACE, granulomatous lung lesions in specimens obtained by TBLB and abnormal Ga accumulation in lung or hilar lymphnodes in sarcoid patients was observed, suggesting that SACE might reflect the degree of granuloma formation in sarcoidosis. (J.P.N.)

  7. Niemann-Pick C1-Like 1 (NPC1L1) Protein in Intestinal and Hepatic Cholesterol Transport

    Jia, Lin; Betters, Jenna L.; Yu, Liqing

    2014-01-01

    Increased blood cholesterol is an independent risk factor for atherosclerotic cardiovascular disease. Cholesterol homeostasis in the body is controlled mainly by endogenous synthesis, intestinal absorption, and hepatic excretion. Niemann-Pick C1-Like 1 (NPC1L1) is a polytopic transmembrane protein localized at the apical membrane of enterocytes and the canalicular membrane of hepatocytes. It functions as a sterol transporter to mediate intestinal cholesterol absorption and counterbalances hepatobiliary cholesterol excretion. NPC1L1 is the molecular target of ezetimibe, a potent cholesterol absorption inhibitor that is widely used in treating hypercholesterolemia. Recent findings suggest that NPC1L1 deficiency or ezetimibe treatment also prevents diet-induced hepatic steatosis and obesity in addition to reducing blood cholesterol. Future studies should focus on molecular mechanisms underlying NPC1L1-dependent cholesterol transport and elucidation of how a cholesterol transporter modulates the pathogenesis of metabolic diseases. PMID:20809793

  8. The Design of an Asic Control Chip for a Forward Active Clamp Converter and the Investigation of Integratable Lateral Power Devices

    Dong, Wei

    1997-01-01

    In Part I, the design of an ASIC control chip for a forward active clamp converter is presented. Integration of the control and drive circuit into one IC chip results in higher power density, higher reliability for the converter module. The designed ASIC control chip uses a 2.0 um N well Analog CMOS process, and is fabricated at MOSIS. The design procedures of the ASIC chip are explained, and experimental results are presented. Part II of the thesis focuses on the numerical investigat...

  9. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    Kosicek, Marko, E-mail: marko.kosicek@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Malnar, Martina, E-mail: martina.malnar@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Goate, Alison, E-mail: goate@icarus.wustl.edu [Department of Psychiatry, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110 (United States); Hecimovic, Silva, E-mail: silva.hecimovic@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia)

    2010-03-12

    It has been suggested that cholesterol may modulate amyloid-{beta} (A{beta}) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD ({beta}-amyloid precursor protein (APP), {beta}-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/A{beta} formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1{sup -/-} cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, {gamma}-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards A{beta} occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  10. Genetic variation at the NPC1L1 gene locus, plasma lipoproteins, and heart disease risk in the elderly

    Niemann-Pick C1-like 1 protein (NPC1L1) plays a critical role in intestinal cholesterol absorption. Our objective was to examine whether five variants (-133A>G, -18A>C, L272L, V1296V, and U3_28650A>G) at the NPC1L1 gene have effects on lipid levels, prevalence, and incidence of coronary heart diseas...

  11. Design of an integrated thermoelectric generator power converter for ultra-low power and low voltage body energy harvesters aimed at ExG active electrodes

    Ataei, Milad; Robert, Christian; Boegli, Alexis; Farine, Pierre-André

    2015-10-01

    This paper describes a detailed design procedure for an efficient thermal body energy harvesting integrated power converter. The procedure is based on the examination of power loss and power transfer in a converter for a self-powered medical device. The efficiency limit for the system is derived and the converter is optimized for the worst case scenario. All optimum system parameters are calculated respecting the transducer constraints and the application form factor. Circuit blocks including pulse generators are implemented based on the system specifications and optimized converter working frequency. At this working condition, it has been demonstrated that the wide area capacitor of the voltage doubler, which provides high voltage switch gating, can be eliminated at the expense of wider switches. With this method, measurements show that 54% efficiency is achieved for just a 20 mV transducer output voltage and 30% of the chip area is saved. The entire electronic board can fit in one EEG or ECG electrode, and the electronic system can convert the electrode to an active electrode.

  12. Design of an integrated thermoelectric generator power converter for ultra-low power and low voltage body energy harvesters aimed at ExG active electrodes

    This paper describes a detailed design procedure for an efficient thermal body energy harvesting integrated power converter. The procedure is based on the examination of power loss and power transfer in a converter for a self-powered medical device. The efficiency limit for the system is derived and the converter is optimized for the worst case scenario. All optimum system parameters are calculated respecting the transducer constraints and the application form factor. Circuit blocks including pulse generators are implemented based on the system specifications and optimized converter working frequency. At this working condition, it has been demonstrated that the wide area capacitor of the voltage doubler, which provides high voltage switch gating, can be eliminated at the expense of wider switches. With this method, measurements show that 54% efficiency is achieved for just a 20 mV transducer output voltage and 30% of the chip area is saved. The entire electronic board can fit in one EEG or ECG electrode, and the electronic system can convert the electrode to an active electrode. (paper)

  13. The NPC1L1 Polymorphism 1679C>G Is Associated with Gallstone Disease in Chinese Patients

    Fei, Jian; Zhang, Sheng-Dao; Han, Tian-Quan; Hu, Hai; Jiang, Zhao-Yan

    2016-01-01

    Niemann Pick Type C1 Like 1 (NPC1L1) protein plays a key role in intestinal and hepatic cholesterol metabolism in humans. Genetic variation in NPC1L1 has been widely studied in recent years. We analyzed NPC1L1 single nucleotide polymorphisms in Chinese gallstone disease patients to investigate their association with gallstone disease. NPC1L1 mRNA expression was also measured in liver biopsies from patients with cholesterol gallstone disease and compared between genotypes. The G allele of the g1679C>G (rs2072183) polymorphism was significantly more prevalent in patients with gallstones compared with gallstone-free subjects. Moreover, patients carrying the G allele had lower hepatic NPC1L1 mRNA expression and higher biliary cholesterol (molar percentages) and cholesterol saturation index. Our study suggests that the G allele of the NPC1L1 polymorphism g1679C>G may be a positive marker of gallstone formation risk. PMID:26800364

  14. The NPC1L1 Polymorphism 1679C>G Is Associated with Gallstone Disease in Chinese Patients.

    Jian Wu

    Full Text Available Niemann Pick Type C1 Like 1 (NPC1L1 protein plays a key role in intestinal and hepatic cholesterol metabolism in humans. Genetic variation in NPC1L1 has been widely studied in recent years. We analyzed NPC1L1 single nucleotide polymorphisms in Chinese gallstone disease patients to investigate their association with gallstone disease. NPC1L1 mRNA expression was also measured in liver biopsies from patients with cholesterol gallstone disease and compared between genotypes. The G allele of the g1679C>G (rs2072183 polymorphism was significantly more prevalent in patients with gallstones compared with gallstone-free subjects. Moreover, patients carrying the G allele had lower hepatic NPC1L1 mRNA expression and higher biliary cholesterol (molar percentages and cholesterol saturation index. Our study suggests that the G allele of the NPC1L1 polymorphism g1679C>G may be a positive marker of gallstone formation risk.

  15. Association of plasminogen activator inhibitor-1 and angiotensin converting enzyme polymorphisms with recurrent pregnancy loss in Iranian women

    Fatemeh Shakarami

    2015-10-01

    Full Text Available Background: Recurrent pregnancy loss (RPL defined by two or more failed pregnancies before 20 weeks of gestation. Several factors play a role in RPL including thrombophilic conditions which can be influenced by gene polymorphisms. Plasminogen activator inhibitor-1 (PAI-1 and angiotensin converting enzyme (ACE genes are closely related to fibrinolytic process, embryonic development and pregnancy success. Objective: The aim of this study was to investigate the relationship between RPL and common polymorphisms in ACE and PAI-1 genes. Materials and Methods: In this case control study, 100 women with recurrent abortions (at least two were selected as cases and 100 healthy women with two or more normal term deliveries without a history of abortion as controls. Total genomic DNA was isolated from blood leukocytes. The status of the PAI-1 4G/5G and ACE (D/I polymorphism was determined by PCR-RFLP. Results: Homozygosity for PAI-1 4G polymorphism was seen in 17 cases (17%, and 5 controls (5% (p=0.006 so patients with homozygote 4G mutation were significantly more prone to RPL in contrast to control group (OR: 4.63, % 95 CI: 1.55-13.84. In addition, 7 patients (7 %, and no one from the control group, were homozygote (I/I for ACE polymorphism (p=0.034, suggesting no significant associations between ACE D allele or DD genotype and RPL. Conclusion: Considering these results, because 4G/4G polymorphism for PAI-1 gene could be a thrombophilic variant leading to abortion, analysis of this mutation and other susceptibility factors are recommended in patients with RPL.

  16. Effects of hydrolysis and digestion in vitro on the activity of bovine plasma hydrolysates as inhibitors of the angiotensin I converting enzyme

    Leidy Johanna Gómez Sampedro; José Edgar Zapata Montoya

    2014-01-01

    The angiotensin I-converting enzyme (ACE) inhibiting activity of bovine plasma hydrolyzates obtained by Alcalase 2.4 L at different degrees of hydrolysis (DH) was evaluated. For the evaluation of ACE inhibition (ACEI), Hippuryl-His-Leu was used as substrate and the amount of hippuric acid liberated by non-inhibiting ACE was determined by spectrophotometry at 228 nm. The results showed that the enzymatic hydrolysis increased the ACEI activity as compared with the un-hydrolyzed plasma. The high...

  17. EFFECT OF CURCUMIN LIPOSOMAL FORM ON ANGIOTENSIN CONVERTING ACTIVITY, CYTOKINES AND COGNITIVE CHARACTERISTICS OF THE RATS WITH ALZHEIMER’S DISEASE MODEL

    V. V. SOKOLIK; S. M. SHULGA

    2015-01-01

    The purpose of the study was the investigation of curcumin liposome form effect on angiotensinconverting enzyme activity, cytokines and mnestic features of rats with experimental model of Alzheimer’s disease. In the animals with intrahippocampal injection of А42_Human, nasal therapy with curcumin liposome form was used. Cytokine concentration and angiotensin converting enzyme activity in brain regions (cerebral cortex and hippocampus) and in blood serum as well as indicators of conditioned a...

  18. Single stage single phase active power factor corrected Ĉuk Topology Based AC-DC Converter

    Md. Ismail Hossain

    2014-03-01

    Full Text Available This paper focuses on the analysis of a power factor correction (PFC converter using close loop Ĉuk topology. Regardless of the input line voltage and output load variations, input current drawn by the buck or buck-boost converter is always discontinuous. The Boost converter suffers from high voltage stresses across the power electronic devices. The input current in Ĉuk converter is comparable to boost converter’s input current. In this paper output voltage is controlled by inner current and outer voltage control loop along with power factor correction (PFC. It shows less input current THD, nearly unity power factor and better output voltage regulation of AC-DC converter under variable input voltage and output load. In this paper the relative performance between normal diode rectifier, open loop Ĉuk rectifier and close loop Ĉuk rectifier is presented. An algorithm for implementing close loop Ĉuk rectifier in digital domain is developed and simulated.

  19. Parallel input parallel output high voltage bi-directional converters for driving dielectric electro active polymer actuators

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.;

    2014-01-01

    Dielectric electroactive polymer (DEAP) actuators are capacitive devices which provide mechanical motions when charged electrically. The charging characteristics of a DEAP actuator depends on its size, voltage applied to its electrodes, and its operating frequency. The main idea of this paper is to......-DC converter incorporating commercially available high voltage MOSFETs (4 kV) and high voltage diodes (5 kV). Although the average current of the aforementioned devices is limited to 300 mA and 150 mA, respectively, connecting the outputs of multiple converters in parallel can provide a scalable design. This...... enables operating the DEAP actuators in various static and dynamic applications e.g. positioning, vibration generation or damping, and pumps. The proposed idea is experimentally verified by connecting three high voltage converters in parallel to operate a single DEAP actuator. The experimental results...

  20. Prognostic value of anti-Epstein-Barr virus antibodies in nasopharyngeal carcinoma (NPC)

    Eighty patients with histological diagnoses of nasopharyngeal cancer (NPC) were referred to Chang-Hua Christian Hospital for curative radiotherapy from 1985 to 1995. A mean dose of 7,020 cGy in 39 fractions was delivered to the primary tumor using a telecobalt-60 unit or 6-10 MV X-ray linear accelerator. Pre- and postradiotherapy serum levels of anti-Epstein-Barr virus (EBV)/VCA IgG and IgA were determined for all patients using the indirect immunoperoxidase assay. Multivariate analysis was done to determine which factors affected the patients' treatment outcome and survival. Five patients were excluded from this study due to incomplete radiotherapy, leaving 75 patients eligible for analysis. Overall local control was 77.3%, with a mean disease-free interval of 19.7 months. Factors affecting local control included radiation dose and pretreatment anti-EBV/VCA IgG titer. The overall 5-year actuarial survival for the 75 patients was 75%, with a median survival of 129.5 months. The 5-year actuarial survival rates for stage I+II, III, and IV patients were 90%, 40%, and 45%, respectively. Prognostic factors for survival included tumor histological type and pretreatment anti-EBV/VCA IgA titer, while prognostic factors for local control included total radiation dose received and pretreatment anti-EBV/VCA IgG titer. We found that there was a significant difference in the geometric mean titer of anti-EBV/VCA IgA antibodies before and after radiotherapy. Prognostic factors affecting NPC patients' actuarial survival included tumor histology and pretreatment IgA titer, while prognostic factors for local control of NPC included total radiation dose received and pretreatment IgG titer. (K.H.)

  1. Modulation Methods for Neutral-Point-Clamped Wind Power Converter Achieving Loss and Thermal Redistribution Under Low-Voltage Ride-Through

    Ma, Ke; Blaabjerg, Frede

    2014-01-01

    paper investigates the loss and thermal performances of a 10-MW 3L-NPC wind power inverter undergoing low-voltage ride-through (LVRT) operation. A series of new space vector modulation methods is then proposed to relocate the thermal loading among the power switching devices. It is concluded that, with......The three-level neutral-point (NP)-clamped (3L-NPC) converter is a promising multilevel topology in the application of megawatt wind power generation systems. However, the growing requirements by grid codes may impose high stress and even give reliability problem to this converter topology. This...... the proposed modulation methods, the thermal distribution in the 3L-NPC wind power inverter undergoing LVRT becomes more equal, and the junction temperature of the most stressed devices can be also relieved. Also, the control ability of the dc-bus NP potential, which is one of the crucial...

  2. A Self-commissioning Notch Filter for Active Damping in a Three-Phase LCL -Filter-Based Grid-Tie Converter

    Pena-Alzola, Rafael; Liserre, Marco; Blaabjerg, Frede;

    2014-01-01

    LCL-filters are a cost-effective solution to mitigate harmonic current content in grid-tie converters. In order to avoid stability problems, the resonance frequency of LCL-filters can be damped with active techniques that remove dissipative elements but increase control complexity. A notch filter...... impedance variations due to its ability to tune the grid-tie inverter on-site. Finally, the analysis is validated with both simulation and experiments....

  3. Top-down Targeted Metabolomics Reveals a Sulfur-Containing Metabolite with Inhibitory Activity against Angiotensin-Converting Enzyme in Asparagus officinalis.

    Nakabayashi, Ryo; Yang, Zhigang; Nishizawa, Tomoko; Mori, Tetsuya; Saito, Kazuki

    2015-05-22

    The discovery of bioactive natural compounds containing sulfur, which is crucial for inhibitory activity against angiotensin-converting enzyme (ACE), is a challenging task in metabolomics. Herein, a new S-containing metabolite, asparaptine (1), was discovered in the spears of Asparagus officinalis by targeted metabolomics using mass spectrometry for S-containing metabolites. The contribution ratio (2.2%) to the IC50 value in the crude extract showed that asparaptine (1) is a new ACE inhibitor. PMID:25922884

  4. Neuroprotection Induced by Preconditioning with Prolonged and Intermittent Normobaric Hyperoxia Upregulate TNF-α Converting Enzyme and Increase NF-kB Activity in the Rat Stroke Model

    MR. Bigdeli

    2008-01-01

    Full Text Available Objective: Ischemic preconditioning (IPC is an endogenous phenomenon that caninduce ischemic tolerance (IT in variety of organs such as brain. In this study, weexamined the intermittent and prolonged dose of normobaric hyperoxia (NBHOin neurologic deficit scores, NF-kB activity, and TNF-α converting enzyme (TACEexpression.Materials and Methods: The rats were divided to four main groups. First twogroups were exposed to HO divided in prolonged (24hrs; PrHO and intermittent(4h×6 days; InHO groups. Second two groups acted as control groups and theywere exposed to 21% oxygen with the following condition: in the same chamber(room air, RA, continuously (24hrs; Pr RA and discontinuously (4h×6days; InRA.Each group was subdivided to three subgroups. After 24hrs, first subgroup wassubjected to 60mins MCAO followed by 24hrs of reperfusion. Then, IT, induced byInHO and PrHO, was measured by neurologic deficit scores and infarct volume.Second and third subgroups were respectively called sham-operated subgroup andintact subgroup designed to assess the effect of HO on NF-kB activity and TNF-αconverting enzyme expression.Results: Our findings indicate that InHO and PrHO are involved in the induction ofIT. Pretreatment with InHO and PrHO reduce neurologic deficit scores and infarctvolume significantly. InHO and PrHO increase NF-kB activity and TNF-α convertingenzyme expression with different degrees. Also, InHO with ischemia increase NF-kBactivity and TNF-α converting enzyme expression significantly.Conclusion: Although further studies are needed to clarify the mechanisms ofischemic tolerance, InHO and PrHO seem partly to exert their effects via increasingNF-kB activity and up regulation of TNF-α converting enzyme.

  5. Flicker Mitigation by Active Power Control of Variable-Speed Wind Turbines With Full-Scale Back-to-Back Power Converters

    Hu, Weihao; Chen, Zhe; Wang, Zhaoan; Wang, Yue

    2009-01-01

    Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation.This paper presents a simulation model of a megawatt-level variablespeed wind turbine with a full-scale back-to-back power converter developed in the simulation tool of PSCAD/EMTDC. Fli......Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation.This paper presents a simulation model of a megawatt-level variablespeed wind turbine with a full-scale back-to-back power converter developed in the simulation tool of PSCAD....../EMTDC. Flicker emission of this system is investigated. Reactive power compensation is mostly adopted for flicker mitigation. However, the flicker mitigation technique shows its limits, when the grid impedance angle is low in some distribution networks. A new method of flicker mitigation by controlling active...... power is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the dc-link voltage of the full-scale converter. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation controller is an...

  6. Distribution and radioimmunoimaging of 131I labeled anti-NPC monoclonal antibody BAC5 in tumor bearing nude mice

    To provide an evidence for clinical applications, the distribution and radioimmunoimaging of 131I labeled anti nasopharyngeal carcinoma (NPC) monoclonal antibody BAC5 in tumor bearing nude mice were studied. McAb BAC5, against NPC, was labeled with 131I and injected into nude mice bearing NPC cell line CNE-2. The biodistribution of 131I-BAC5 and whole body ECT imaging were studied at various intervals after injection. The % ID/g were 6.38, 11.27 and 14.19 for tumor and 7.78, 3.48 and 2.59 for liver at 48, 96 and 144h postinjection respectively. The T/NT ratios were 0.82, 3.24 and 5.47 for liver at 48, 96 and 144h postinjection respectively. Tumor showed clearly at 3 days after injection. The quality of tumor images was relevant to the T/NT ratio. The results demonstrated that McAb BAC5 has specifically bind to NPC tissue and may also possess the capability of leading to human NPC

  7. Multi-functional Converter with Integrated Motor Control, Battery Charging and Active Module Balancing for Electric Vehicular Application

    Mathe, Laszlo; Schaltz, Erik; Teodorescu, Remus; Haddioui, Marcos Rejas

    2014-01-01

    In order to reduce the fuel consumption and the acoustical noise generated by refuse lorries, electrification of the waste compactor unit is a very promising solution. For the electrical energy storage Lithium-Sulfur (Li-S) battery technology has been selected with potential for reducing the cost, weight and volume in comparison with other Li-Ion based chemistries. The control of the energy flow has been done through a Modular Multilevel Converter (MMC), which has demonstrated advantages over...

  8. Comprehensive Loss Evaluation of Neutral-Point-Clamped (NPC) and T-Type Three-Level Invertersbased on a Circuit Level Decoupling Modulation

    Zhang, Zhe; Anthon, Alexander; Andersen, Michael A. E.

    In this paper, an efficiency comparison ofneutral-point-clamped (NPC) inverters and bipolar switch NPC(T-Type) inverters is studied and the result shows that the T-Type inverter is more efficient at lower switching frequencies.Nevertheless, its efficiency suffers when the switching frequencyincre......In this paper, an efficiency comparison ofneutral-point-clamped (NPC) inverters and bipolar switch NPC(T-Type) inverters is studied and the result shows that the T-Type inverter is more efficient at lower switching frequencies.Nevertheless, its efficiency suffers when the switching...... orderto achieve superior output voltage quality without loweringefficiency....

  9. KARAKTERISTIK FISIK, KIMIA, MIKROBIOLOGI WHEY KEFIR DAN AKTIVITASNYA TERHADAP PENGHAMBATAN ANGIOTENSIN CONVERTING ENZYME (ACE [Physical, Chemical and Microbiological Characteristics of Whey Kefir and Its Angiotensin Converting Enzyme (ACE Inhibitory Activity

    Andi Febrisiantosa*

    2013-12-01

    Full Text Available This study was conducted to evaluate the characteristics of whey-based kefir products and their activity to inhibit the angiotensin converting enzyme (ACE. Kefir was produced by using many types of whey, namely SK: skim milk based kefir (control; WK: gouda cheese whey based kefir; and WKB: commercial whey powder based kefir. The experimental design was a completely randomized design. Each treatment was conducted in triplicates. Kefirs were evaluated for physical and chemical properties (pH, total titratable acidity, viscosity, protein, fat, lactose, and alcohol, microbiological (lactic acid bacteria and yeast population, peptide concentration, ACE inhibition, IC50 and Inhibition Efficiency Ratio (IER. The results showed that the types of whey used for kefir productions significantly affected the physical and chemical characteristics of the products (p0.05. The peptide concentration and ACE inhibitory activity of WK, 1.54±0.02 mg/mL and 73.07±0.91%, was significantly higher (p0.05 from the control (47.19±0.09% per mg/mL but was significantly higher (p<0.05 than that of WKB (45.75±0.18% per mg/mL. This research indicated that whey kefir is a potential source of bioactive peptide for antihypertention agent.

  10. INCREASED ANGIOTENSIN II INDUCED HYPERTENSION AND INFLAMMATORY CYTOKINES IN MICE LACKING ANGIOTENSIN CONVERTING ENZYME N DOMAIN ACTIVITY

    Ong, Frank S.; Lin, Chentao X.; Campbell, Duncan J.; Okwan-Duodu, Derick; Chen, Xu; Blackwell, Wendell-Lamar B.; Shah, Kandarp H.; Gonzalez-Villalobos, Romer A.; Shen, Xiao Z.; Fuchs, Sebastien; Bernstein, Kenneth E.

    2011-01-01

    Angiotensin converting enzyme (ACE) is composed of the N- and C-terminal catalytic domains. To study the role of the ACE domains in the inflammatory response, N-KO and C-KO mice, models lacking one of the two ACE domains, were analyzed during angiotensin II-induced hypertension. At 2 weeks, N-KO mice have systolic blood pressures that averaged 173 ± 4.6 mm Hg, which is more than 25 mm Hg higher than the blood pressures observed in wild-type or C-KO mice (146 ± 3.2 and 147 ± 4.2 mm Hg). After ...

  11. Curcumin inhibits cholesterol uptake in Caco-2 cells by down-regulation of NPC1L1 expression

    Duan Rui-Dong

    2010-04-01

    Full Text Available Abstract Background Curcumin is a polyphenol and the one of the principle curcuminoids of the spice turmeric. Its antioxidant, anti-cancer and anti-inflammatory effects have been intensively studied. Previous in vivo studies showed that administration of curcumin also decreased cholesterol levels in the blood, and the effects were considered to be related to upregulation of LDL receptor. However, since plasma cholesterol levels are also influenced by the uptake of cholesterol in the gut, which is mediated by a specific transporter Niemann-Pick Cl-like 1 (NPC1L1 protein, the present study is to investigate whether curcumin affects cholesterol uptake in the intestinal Caco-2 cells. Methods Caco-2 cells were cultured to confluence. The micelles composed of bile salt, monoolein, and 14C-cholesterol were prepared. We first incubated the cells with the micelles in the presence and absence of ezetimibe, the specific inhibitor of NPC1L1, to see whether the uptake of the cholesterol in the cells was mediated by NPC1L1. We then pretreated the cells with curcumin at different concentrations for 24 h followed by examination of the changes of cholesterol uptake in these curcumin-treated cells. Finally we determined whether curcumin affects the expression of NPC1L1 by both Western blot analysis and qPCR quantification. Results We found that the uptake of radioactive cholesterol in Caco-2 cells was inhibited by ezetimibe in a dose-dependent manner. The results indicate that the uptake of cholesterol in this study was mediated by NPC1L1. We then pretreated the cells with 25-100 μM curcumin for 24 h and found that such a treatment dose-dependently inhibited cholesterol uptake with 40% inhibition obtained by 100 μM curcumin. In addition, we found that the curcumin-induced inhibition of cholesterol uptake was associated with significant decrease in the levels of NPC1L1 protein and NPC1L1 mRNA, as analyzed by Western blot and qPCR, respectively. Conclusion

  12. Optimization of SiC-based H5 and Conergy-NPC transformerless PV inverters

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    design technique is presented for optimizing the switching frequency and structure of the LCL-type output filter in transformerless H5 and Conergy-NPC PV inverters, which employ SiC-type power devices. The design optimization results demonstrate that the optimized SiC-based PV inverters are more......The transformerless DC/AC inverters are critical components in the rapidly growing market of grid-connected Photovoltaic (PV) applications. Also, the SiC-based power semiconductors are capable to operate reliably at high operating temperature and switches frequency levels. In this paper, a new...... effective in terms of energy production than their non-optimized and Si-based counterparts. Reducing the market price of SiC-type power semiconductors enables to design optimized PV inverters with a lower cost of energy than that of PV inverters employing Si technology, thus maximizing the economic...

  13. Freeing the Mind and Innovating to Leap Mead——Interview of NPC Deputy,Li Qiang

    2008-01-01

    @@ During the interview, NPC Deputy, Vice Secretary of the Municipal Committee and Mayor of Yan Cheng, Li Qiang pointed out that Yan Cheng can realize a great transformation and increased development only by applying the principles of scientific thinking together with a free mind and innovation.

  14. Virtual-vector-based space vector pulse width modulation of the DC-AC multilevel-clamped multilevel converter (MLC2)

    Rodriguez, Pedro; Busquets-Monge, Sergio; Blaabjerg, Frede; Munoz-Aguilar, Raul S.; Bellar, Maria D.

    This work presents the development of the space vector pulse width modulation (SVPWM) of a new multi-level converter topology. First, the proposed converter and its natural space vector diagram are presented. Secondly, a modified space vector diagram based on the virtual-vectors technique is shown....... Simulation results by using a space vector approach are presented. Special emphasis is given on the total harmonic distortion (THD) by making a comparison with those of the classical NPC topologies....

  15. Bioactivity comparison of extracts from various parts of common and tartary buckwheats: evaluation of the antioxidant- and angiotensin-converting enzyme inhibitory activities

    Tsai Hweiyan

    2012-08-01

    Full Text Available Abstract Background Buckwheat flour and buckwheat sprouts possess antioxidant properties, and previous studies have reported on buckwheat flour displaying an inhibitory activity for angiotensin-I converting enzyme (ACE. Information is lacking on the bioactivity of other parts of the buckwheat, such as the seed hulls and plant stalks. This study investigates the ACE inhibitory activity and antioxidant activity of various parts of 2 types of buckwheat, namely, common buckwheat (Fagopyrum esculentum Moench and tartary buckwheat (Fagopyrum tataricum Gaertn. Results The extract of common hulls extracted using 50% (v/v-ethanol solvent presented a remarkable inhibitory activity. The value of IC50 is 30 μg ml-1. The extracts of both common and tartary hulls extracted using 50% (v/v-ethanol solvent demonstrated an antioxidant activity that is superior to that of other extracts. Conclusion This study determined that the ethanolic extract of the hulls of common buckwheat presented more favorable antioxidant and ACE inhibitory abilities. However, the correlation of antioxidant activity and ACE inhibitory activity for all 18 types of extracts is low. The ACE inhibitory activity could have been caused by a synergistic effect of flavonoids or from other unidentified components in the extracts. The ethanolic extract of common hulls demonstrated remarkable ACE inhibitory activity and is worthy of further animal study.

  16. A single leg switched PWM method for three-phase H-Bridge Voltage Source Converters

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig; Rodriguez, Pedro; Teodorescu, Remus

    This paper proposes a single leg switched or a hybrid PWM (HPWM) method for three-phase three-level H-Bridge Voltage Source Converters (3L-HB-VSCs). By means of the proposed modulation, a 3L-HB-VSC can generate the same output as a three-level neutral point clamped (3L-NPC) VSC with phase...... disposition (PD) PWM provided that the outputs of 3L-HBVSC are isolated by transformers or connected to open winding machines. Thus, the proposed method is called PD-HPWM. Moreover, it is emphasized that 3L-HB-VSC with HPWM utilizes its switches similar to 3L-NPC-VSC. Compared to 3L-NPC-VSCs, 3L......-HB-VSCs (without neutral point clamping diodes) have simpler, more modular, and more reliable 2L circuit structure. Therefore, this method encourages the use of 3L-HB-VSCs in the applications utilizing transformers such as grid-side converters of multi-MW wind turbines. The proposed PWM method's performance is...

  17. Short communication: Measuring the angiotensin-converting enzyme inhibitory activity of an 8-amino acid (8mer) fragment of the C12 antihypertensive peptide.

    Paul, Moushumi; Phillips, John G; Renye, John A

    2016-05-01

    An 8-AA (8mer) fragment (PFPEVFGK) of a known antihypertensive peptide derived from bovine αS1-casein (C12 antihypertensive peptide) was synthesized by microwave-assisted solid-phase peptide synthesis and purified by reverse phase HPLC. Its ability to inhibit angiotensin-converting enzyme (ACE) was assessed and compared with that of the parent 12mer peptide (FFVAPFPEVFGK) to determine the effect of truncating the sequence on overall hypotensive activity. The activity of the truncated 8mer peptide was found to be almost 1.5 times less active than that of the 12mer, with ACE-inhibiting IC50 (half-maximal inhibitory concentration) values of 108 and 69μM, for the 8mer and 12mer, respectively. Although the 8mer peptide is less active than the original 12mer peptide, its overall activity is comparable to activities reported for other small proteins that elicit physiological responses within humans. These results suggest that microbial degradation of the 12mer peptide would not result in a complete loss of antihypertensive activity if used to supplement fermented foods and that the stable 8mer peptide could have potential as a blood pressure-lowering agent for use in functional foods. PMID:26971162

  18. Effects of hydrolysis and digestion in vitro on the activity of bovine plasma hydrolysates as inhibitors of the angiotensin I converting enzyme

    Leidy Johanna Gómez Sampedro

    2014-06-01

    Full Text Available The angiotensin I-converting enzyme (ACE inhibiting activity of bovine plasma hydrolyzates obtained by Alcalase 2.4 L at different degrees of hydrolysis (DH was evaluated. For the evaluation of ACE inhibition (ACEI, Hippuryl-His-Leu was used as substrate and the amount of hippuric acid liberated by non-inhibiting ACE was determined by spectrophotometry at 228 nm. The results showed that the enzymatic hydrolysis increased the ACEI activity as compared with the un-hydrolyzed plasma. The highest activity was onbtained with a DH of 6.7%. The peptide fractions with the maximum activity were isolated using ultrafiltration membranes, ion exchange chromatography and high performance liquid chromatography on reverse phase (RP-HPLC. The fraction with highest ACEI activity, showed an IC50 of 0.18 mg/mL and contained peptides with sequences AGATGVTISGAG, YSRRHPEYAVS, Q(KAW and L(lI(IVR, which were determined by MALDI-TOF-TOF. It was also found that after submitting such fraction to digestive conditions in vitro, the ACEI activity remained constant.

  19. Operating and Loading Conditions of a Three-Level Neutral-Point-Clamped Wind Power Converter Under Various Grid Faults

    Ma, Ke; Liserre, Marco; Blaabjerg, Frede

    2014-01-01

    In order to fulfill the growing demands from the grid side, full-scale power converters are becoming popular in the wind turbine system. The low-voltage ride-through (LVRT) requirements may not only cause control problems but also result in overstressed components for the power converter. However......, the thermal loading of the wind power converter under various grid faults is still not yet clarified, particularly at megawatt power level. In this paper, the impacts by three types of grid faults to a three-level neutral-point-clamped (3L-NPC) wind power converter in terms of operating and loading...... conditions are analytically solved and simulated. It has been found that the operating and loading conditions of the converter under LVRT strongly depend on the types/severity values of grid voltage dips and also the chosen control algorithms. The thermal distribution among the three phases of the converter...

  20. PDE5 is converted to an activated state upon cGMP binding to the GAF A domain

    Rybalkin, Sergei D.; Rybalkina, Irina G.; Shimizu-Albergine, Masami; Tang, Xiao-Bo; Beavo, Joseph A.

    2003-01-01

    cGMP-specific, cGMP-binding phosphodiesterase (PDE5) regulates such physiological processes as smooth muscle relaxation and neuronal survival. PDE5 contains two N-terminal domains (GAF A and GAF B), but the functional roles of these domains have not been determined. Here we show that recombinant PDE5 is activated directly upon cGMP binding to the GAF A domain, and this effect does not require PDE5 phosphorylation. PDE5 exhibited time- and concentration-dependent reversible activation in respo...

  1. Wavelength converter technology

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers....

  2. Wavelength converter technology

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov; Wolfson, David; Jepsen, Kim Stokholm; Clausen, Anders; Limal, Emmanuel; Buxens, Alvaro A.

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers.......Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers....

  3. Impact of modulation strategies on power devices loading for 10 MW multilevel wind power converter

    Blaabjerg, Frede; Isidori, Andrea; Rossi, Fabio Mario

    This paper focuses on the control and modulation of a three-level Neutral Point Clamped (3L-NPC) back-to-back full scale converter for a 10 MW direct-drive wind turbine, equipped with a Permanent Magnet Synchronous Generator (PMSG). Emphasis is oriented towards the investigation of the power losses...... environment to analyse the dynamics of the system using different kinds of modulation strategies, identifying which methods can improve the converter efficiency. It is concluded that 60° discontinuous PWM modulation strategies show less power losses in the semiconductor devices and will increase the overall...... in the semiconductor devices of three-level converter adopting continuous and discontinuous PWM modulation strategies. This aspect strongly influences the operation of the converter and directly affects its efficiency. Therefore, a simulation platform is developed in Matlab/Simulink and PLECS...

  4. Thermal loading and reliability of 10 MW multilevel wind power converter at different wind roughness classes

    Isidori, Andrea; Rossi, Fabio Mario; Blaabjerg, Frede

    2012-01-01

    This paper focuses on the design, thermal loading and reliability of a three-level Neutral Point Clamped (3-L NPC) back-to-back full scale converter for a 10 MW direct-drive wind turbine equipped with a Permanent Magnet Synchronous Generator (PMSG). The reliability performance of the three......-level converter is strongly influenced by the thermal behaviour of the semiconductor devices and their mission profile which directly affects the lifetime and the cost of the whole converter. Therefore, the simulation platform is developed in Matlab/Simulink and PLECS simulation environment to analyse the...... dynamics of the system using different kinds of modulation strategies and analyzing different wind load conditions dependent on roughness classes. It is concluded that 60° discontinuous PWM modulation strategies show better thermal performance and increase the estimated lifetime of the converter...

  5. Systematic Design of the Lead-Lag Network Method for Active Damping in LCL-Filter Based Three Phase Converters

    Alzola, Rafael Pena; Liserre, Marco; Blaabjerg, Frede; Sebastián, Rafael; Dannehl, Jörg; Wilhelm Fuchs, Friedrich

    2014-01-01

    Three-phase active rectifiers guarantee sinusoidal input currents and unity power factor at the price of a high switching frequency ripple. To adopt an LCL-filter, instead of an L-filter, allows using reduced values for the inductances and so preserving dynamics. However, stability problems can...... arise in the current control loop if the present resonance is not properly damped. Passive damping simply adds resistors in series with the LCL-filter capacitors. This simplicity is at the expense of increased losses and encumbrances. Active damping modifies the control algorithm to attain stability...... without using dissipative elements but, sometimes, needing additional sensors. This solution has been addressed in many publications. The lead-lag network method is one of the first reported procedures and continues being in use. However, neither there is a direct tuning procedure (without trial and error...

  6. Preparation of bioactive peptides with high angiotensin converting enzyme inhibitory activity from winged bean [Psophocarpus tetragonolobus (L.) DC.] seed.

    Wan Mohtar, Wan Abd Al-Qadr Imad; Hamid, Azizah Abdul; Abd-Aziz, Suraini; Muhamad, Sharifah Kharidah Syed; Saari, Nazamid

    2014-12-01

    Winged bean [Psophocarpus tetragonolobus (L.) DC.] seed is a potential underexploited source of vegetable protein due to its high protein content. In the present work, undefatted and defatted winged bean seed hydrolysates, designated as UWBSH and DWBSH, respectively were produced separately by four proteolytic enzymes namely Flavourzyme, Alcalase, Bromelain, and Papain using pH-stat method in a batch reactor. Enzymatic hydrolysis was carried out over a period of 0.5 to 5 h. UWBSH and DWBSH produced were tested for their ACE inhibitory activity in relation to the hydrolysis time and degree of hydrolysis (DH). Maximum ACE inhibitory activity, both for UWBSH and DWBSH, were observed during 3 to 5 h of hydrolysis. Both, UWBSH (DH 91.84 %), and DWSBH (DH 18.72 %), produced by Papain at 5 h hydrolysis, exhibited exceptionally high ACE inhibitory activity with IC50 value 0.064 and 0.249 mg mL(-1), respectively. Besides, papain-produced UWBSH and DWBSH were further fractionated into three fractions based on molecular weight (UWBSH-I, <10 kDa; UWBSH-II, <5 kDa; UWBSH-III, <2 kDa) and (DWBSH-I, <10 kDa; DWBSH-II, <5 kDa; DWBSH-III, <2 kDa). UWBSH-III revealed the highest ACE inhibitory activity (IC50 0.003 mg mL(-1)) compared with DWBSH-III (IC50 0.130 mg mL(-1)). The results of the present investigation revealed that winged bean seed hydrolysates can be explored as a potential source of ACE inhibitory peptides suggesting their uses for physiological benefits as well as for other functional food applications. PMID:25477632

  7. Implementation Of A Battery Storage System Of An Individual Active Power Control Based On A Cascaded Multilevel Pwm Converter

    RAJASEKHARACHARI K, G.BALASUNDARAM, KUMAR K

    2013-01-01

    For The Smart Grid Arrangement A Battery Energy Storage System Is Important Equipment Of Renewable Energy Resources. In This Paper We Will Have A Discussion On Active Power Control In A Battery Storage System With A Topology Of Cascaded Multi Level Inverter With Pulse Width Modulation Switching Technique. Multilevel Inverters Have Been Attracting In Favor Of Academia As Well As Industry In The Recent Decade For High-Power And Medium-Voltage Energy Control. A Battery Energy Storage System (BES...

  8. Utilisation of rapeseed protein isolates for production of peptides with angiotensin I-converting enzyme (ACE-inhibitory activity

    Vioque, Javier

    2004-12-01

    Full Text Available ACE activity is related to increased arterial pressure and coronary diseases. A rapeseed protein isolate was hydrolyzed with the protease Alcalase in order to investigate the possible presence of ACE inhibitory peptides in the resulting hydrolysates. Hydrolysis for 30 min yielded a hydrolysate with the highest ACE inhibitory activity. Two fractions of this hydrolysate obtained by Biogel P2 gel filtration chromatography were used for further purification of ACE inhibitory peptides. Three fractions with ACE inhibitory activity were purified by reverse-phase HPLC of Biogel P2 f ractions. This demonstrates that rapeseed protein hydrolysates represent a good source of ACE inhibitory peptides .La actividad de ECA está relacionada con una presión arterial alta y enfermedades cardíacas. Un aislado proteico de colza se hidrolizó con alcalasa para estudiar la posible presencia de péptidos inhibidores de ECA en el hidrolizado. La hidrólisis durante 30 min produjo el hidrolizado con la mayor actividad inhibidora de ECA. Dos fracciones de este hidrolizado, obtenidas por cromatografía de filtración en gel Biogel P2, se usaron para la purificación de péptidos inhibidores de ECA. Tres fracciones con actividad inhibidora de ECA se purificaron mediante HPLC en fase reversa de las fracciones obtenidas mediante Biogel P2. Esto demuestra que los hidrolizados proteicos de colza representan una buena fuente de péptidos inhibidores de ECA.

  9. Study and Design of a Dual Active Bridge Resonant Converter%一种双有源桥谐振变换器的研究与设计

    章治国; 余海生

    2012-01-01

    A dual active bridge series resonant converter with bidirectional power flow was studied. An accurate equivalent circuit model considering effects of magnetizing inductance and leakage inductance of transformer was established to derive steady-state characteristics of the converter. Method to select optimal numerical value of magnetizing inductance was developed. Based on detailed analysis, a dual active bridge series resonant DC-DC converter operating at resonant frequency was designed. In this circuit, all switches could work in zero-voltage-switching mode for full range of loads when voltage gain is one. Meanwhile, variation of resonant voltage and current with changing loads was also investigated. Finally, as an example, an experimental circuit was constructed with SABER to demonstrate the effectiveness of theoretical analysis.%以能量双向流动双有源桥(DAB)串联谐振变换器为研究对象,在考虑隔离变压器激磁电感和泄漏电感影响的基础上,建立双有源桥串联谐振变换器的准确等效模型,推导出其稳态工作特性.分析了DAB串联谐振变换器软开关条件和激磁电感最优值选择方法.设计了一种工作在谐振频率处的DAB串联谐振DC/DC变换器,当电压增益M=1时,所有开关在全负载范围内都工作,均能实现ZVS.还分析了负载变化时谐振电压和电流的变化规律.最后给出设计实例,并用SABER仿真软件搭建了实验电路,仿真结果验证了理论分析的有效性.

  10. Green asparagus (Asparagus officinalis) prevented hypertension by an inhibitory effect on angiotensin-converting enzyme activity in the kidney of spontaneously hypertensive rats.

    Sanae, Matsuda; Yasuo, Aoyagi

    2013-06-12

    Green asparagus (Asparagus officinalis) is known to be rich in functional components. In the present study, spontaneously hypertensive rats (SHR) were used to clarify whether green asparagus prevents hypertension by inhibition of angiotensin-converting enzyme (ACE) activity. Six-week-old male SHR were fed a diet with (AD group) or without (ND group) 5% asparagus for 10 weeks. Systolic blood pressure (SBP) (AD: 159 ± 4.8 mmHg, ND: 192 ± 14.7 mmHg), urinary protein excretion/creatinine excretion, and ACE activity in the kidney were significantly lower in the AD group compared with the ND group. Creatinine clearance was significantly higher in the AD group compared with the ND group. In addition, ACE inhibitory activity was observed in a boiling water extract of asparagus. The ACE inhibitor purified and isolated from asparagus was identified as 2″-hydroxynicotianamine. In conclusion, 2″-hydroxynicotianamine in asparagus may be one of the factors inhibiting ACE activity in the kidney, thus preventing hypertension and preserving renal function. PMID:23647085

  11. MRI signal changes in the skull base bone after endoscopic nasopharyngectomy for recurrent NPC: A serial study of 9 patients

    Purpose: This study was focused on the serial changes in magnetic resonance images (MRI) of the skull-base bone that occur after endoscopic nasopharyngectomy in patients with local recurrent nasopharyngeal carcinoma (rNPC). Materials and methods: Nine patients with histologically proven rNPC were enrolled in this study. Two experienced radiologists independently reviewed all presurgical and postsurgical MR images for each patient. Results: At 36 sites on the skull base, the MRI signal underwent a change after surgery, which took the form of a heterogeneous pattern of hypointense regions with moderate contrast enhancement on T1WI. The onset of changes ranged between 2 weeks and 3 months after surgery. For 21 of the sites, the changes subsided over the course of follow-up, while in 6 they remained stable. At 9 sites, the alteration MRI signal became more pronounced with time. Changes were more common on the homolateral side of the skull base with respect to the recurrent tumor (P < 0.05). The skull-base bone adjacent to the resection boundary had a higher incidence of signal change than nonadjacent areas (P < 0.05). Conclusions: MRI changes in the skull base bone, having a number of distinguishing characteristics, appear to be a common sequel to endoscopic nasopharyngectomy for rNPC

  12. Effects of combined 131I- and CT-BAC5 immunotherapy on NPC CNE-2 multicellular spheroids

    Objective: To develop a new specific therapeutic method for treating nasopharyngeal carcinoma (NPC) and to evaluate its effects on an in vitro tumor spheroid model. Methods: The human NPC cell line CNE-2 spheroids were grown in culture medium, on a thin layer of 0.75% agarose. The average volume of the spheroids was estimated by 1/2 (short dimension)2 x (long dimension). Anti-NPC BAC5 MAb was labelled with 131I using chloramine-T method. Cytotoxin from Chinese cobra (CT) was conjugated with BAC5 by hetero bifunctional cross-linking reagent (SPDP). The spheroids were treated with either 131I-BAC5 or CT-BAC5 separately or with both of them together by incubating in culture medium. Results: The conjugated rate of BAC5 and CT was 32.4%. CT-BAC5 significantly inhibited the growth of CNE-2 multicellular spheroids comparing with control agent (normal saline) (P 131I-BAC5 did more than CT-BAC5 (P131I-BAC5 with CT-BAC5 treatment showed even stronger destructive effect on the spheroids (vs. normal saline, P 131I-BAC5 with CT-BAC5 is better than either of them working separately

  13. Rationally designed mutations convert complexes of human recombinant T cell receptor ligands into monomers that retain biological activity

    Huan, Jianya Y; Meza-Romero, Roberto; Mooney, Jeffery L.; Yuan K. Chou; Edwards, David M.; Rich, Cathleen; Link, Jason M.; Vandenbark, Arthur A.; Bourdette, Dennis N.; Bächinger, Hans-Peter; Burrows, Gregory G.

    2004-01-01

    Single-chain human recombinant T cell receptor ligands derived from the peptide binding/TCR recognition domain of human HLA-DR2b (DRA*0101/DRB1*1501) produced in Escherichia coli with and without amino-terminal extensions containing antigenic peptides have been described previously. While molecules with the native sequence retained biological activity, they formed higher order aggregates in solution. In this study, we used site-directed mutagenesis to modify the β-sheet platform of the DR2-de...

  14. Multi-functional Converter with Integrated Motor Control, Battery Charging and Active Module Balancing for Electric Vehicular Application

    Mathe, Laszlo; Schaltz, Erik; Teodorescu, Remus;

    2014-01-01

    In order to reduce the fuel consumption and the acoustical noise generated by refuse lorries, electrification of the waste compactor unit is a very promising solution. For the electrical energy storage Lithium-Sulfur (Li-S) battery technology has been selected with potential for reducing the cost...... used successfully in HVDC/FACTS and large drive applications. In this paper the use of MMC for a battery driven waste compactor unit addressed with integrated functionality including: motor driver, battery charge and active balancing is presented. The challenges addressed here are related to the design...

  15. Rationally designed mutations convert complexes of human recombinant T cell receptor ligands into monomers that retain biological activity.

    Huan, Jianya Y; Meza-Romero, Roberto; Mooney, Jeffery L; Chou, Yuan K; Edwards, David M; Rich, Cathleen; Link, Jason M; Vandenbark, Arthur A; Bourdette, Dennis N; Bächinger, Hans-Peter; Burrows, Gregory G

    2005-01-01

    Single-chain human recombinant T cell receptor ligands derived from the peptide binding/TCR recognition domain of human HLA-DR2b (DRA*0101/DRB1*1501) produced in Escherichia coli with and without amino-terminal extensions containing antigenic peptides have been described previously. While molecules with the native sequence retained biological activity, they formed higher order aggregates in solution. In this study, we used site-directed mutagenesis to modify the β-sheet platform of the DR2-derived RTLs, obtaining two variants that were monomeric in solution by replacing hydrophobic residues with polar (serine) or charged (aspartic acid) residues. Size exclusion chromatography and dynamic light scattering demonstrated that the modified RTLs were monomeric in solution, and structural characterization using circular dichroism demonstrated the highly ordered secondary structure of the RTLs. Peptide binding to the `empty' RTLs was quantified using biotinylated peptides, and functional studies showed that the modified RTLs containing covalently tethered peptides were able to inhibit antigen-specific T cell proliferation in vitro, as well as suppress experimental autoimmune encephalomyelitis in vivo. These studies demonstrated that RTLs encoding the Ag-binding/TCR recognition domain of MHC class II molecules are innately very robust structures, capable of retaining potent biological activity separate from the Ig-fold domains of the progenitor class II structure, with prevention of aggregation accomplished by modification of an exposed surface that was buried in the progenitor structure. PMID:22973070

  16. Rationally designed mutations convert complexes of human recombinant T cell receptor ligands into monomers that retain biological activity

    Huan, Jianya Y; Meza-Romero, Roberto; Mooney, Jeffery L; Chou, Yuan K; Edwards, David M; Rich, Cathleen; Link, Jason M; Vandenbark, Arthur A; Bourdette, Dennis N; Bächinger, Hans-Peter; Burrows, Gregory G

    2012-01-01

    Single-chain human recombinant T cell receptor ligands derived from the peptide binding/TCR recognition domain of human HLA-DR2b (DRA*0101/DRB1*1501) produced in Escherichia coli with and without amino-terminal extensions containing antigenic peptides have been described previously. While molecules with the native sequence retained biological activity, they formed higher order aggregates in solution. In this study, we used site-directed mutagenesis to modify the β-sheet platform of the DR2-derived RTLs, obtaining two variants that were monomeric in solution by replacing hydrophobic residues with polar (serine) or charged (aspartic acid) residues. Size exclusion chromatography and dynamic light scattering demonstrated that the modified RTLs were monomeric in solution, and structural characterization using circular dichroism demonstrated the highly ordered secondary structure of the RTLs. Peptide binding to the `empty' RTLs was quantified using biotinylated peptides, and functional studies showed that the modified RTLs containing covalently tethered peptides were able to inhibit antigen-specific T cell proliferation in vitro, as well as suppress experimental autoimmune encephalomyelitis in vivo. These studies demonstrated that RTLs encoding the Ag-binding/TCR recognition domain of MHC class II molecules are innately very robust structures, capable of retaining potent biological activity separate from the Ig-fold domains of the progenitor class II structure, with prevention of aggregation accomplished by modification of an exposed surface that was buried in the progenitor structure. PMID:22973070

  17. Vitamin E Dietary Supplementation Improves Neurological Symptoms and Decreases c-Abl/p73 Activation in Niemann-Pick C Mice

    Tamara Marín

    2014-07-01

    Full Text Available Niemann-Pick C (NPC disease is a fatal neurodegenerative disorder characterized by the accumulation of free cholesterol in lysosomes. We have previously reported that oxidative stress is the main upstream stimulus activating the proapoptotic c-Abl/p73 pathway in NPC neurons. We have also observed accumulation of vitamin E in NPC lysosomes, which could lead to a potential decrease of its bioavailability. Our aim was to determine if dietary vitamin E supplementation could improve NPC disease in mice. NPC mice received an alpha-tocopherol (α-TOH supplemented diet and neurological symptoms, survival, Purkinje cell loss, α-TOH and nitrotyrosine levels, astrogliosis, and the c-Abl/p73 pathway functions were evaluated. In addition, the effect of α-TOH on the c-Abl/p73 pathway was evaluated in an in vitro NPC neuron model. The α-TOH rich diet delayed loss of weight, improved coordination and locomotor function and increased the survival of NPC mice. We found increased Purkinje neurons and α-TOH levels and reduced astrogliosis, nitrotyrosine and phosphorylated p73 in cerebellum. A decrease of c-Abl/p73 activation was also observed in the in vitro NPC neurons treated with α-TOH. In conclusion, our results show that vitamin E can delay neurodegeneration in NPC mice and suggest that its supplementation in the diet could be useful for the treatment of NPC patients.

  18. 基于LM5025的有源箝位反激变换器的前馈控制%Feed-Forward Control of the Active Clamp Flyback Converters Based on LM5025

    雷明; 程善美; 于孟春; 申勇哲

    2012-01-01

    在有源箝位反激变换器负载基本恒定的情况下采用前馈控制既可以减小变换器体积,又可降低变换器的成本。文中在分析有源箝位反激变换器工作原理的基础上,结合LM5025器件的前馈控制特性,深入研究了基于LM5025的有源箝位反激变换器前馈控制的实现方案,设计了前馈控制电路的参数,完成了有源前馈反激变换器电路设计。在此基础上进行了实验研究,实验结果证明了有源箝位反激变换器前馈控制的有效性和实用性。%Feed-forward control can both reduce the size of the converter volume and reduce the cost of the converter when the active clamp flyback converter load is almost constant. On the basis of the analysis of the active clamp flyback converter working principle, and combined with the feed-forward features of the LM5025 device, the implementation of feed-forward control used in active clamp flyback converter is deeply studied based on the LM5025, and the parameters of the feed-forward control circuit is designed, and the active feed forward flyback converter circuit is implemented. On this basis, the experimental study is earried, and the experimental results show the effectiveness and practicality of the feed-forward control of the active clamp flyback converter.

  19. Effects of Metabolites Produced from (-)-Epigallocatechin Gallate by Rat Intestinal Bacteria on Angiotensin I-Converting Enzyme Activity and Blood Pressure in Spontaneously Hypertensive Rats.

    Takagaki, Akiko; Nanjo, Fumio

    2015-09-23

    Inhibitory activity of angiotensin I-converting enzyme (ACE) was examined with (-)-epigallocatechin gallate (EGCG) metabolites produced by intestinal bacteria, together with tea catechins. All of the metabolites showed ACE inhibitory activities and the order of IC50 was hydroxyphenyl valeric acids > 5-(3,4,5-trihydroxyphenyl)-γ-valerolactone (1) > trihydroxyphenyl 4-hydroxyvaleric acid ≫ dihydroxyphenyl 4-hydroxyvaleric acid ≫ 5-(3,5-dihydroxyphenyl)-γ-valerolactone (2). Among the catechins, galloylated catechins exhibited stronger ACE inhibitory activity than nongalloylated catechins. Furthermore, the effects of a single oral intake of metabolites 1 and 2 on systolic blood pressure (SBP) were examined with spontaneously hypertensive rats (SHR). Significant decreases in SBP were observed between 2 h after oral administration of 1 (150 mg/kg in SHR) and the control group (p = 0.002) and between 4 h after administration of 2 (200 mg/kg in SHR) and the control group (p = 0.044). These results suggest that the two metabolites have hypotensive effects in vivo. PMID:26323573

  20. Registered report: The common feature of leukemia-associated IDH1 and IDH2 mutations is a neomorphic enzyme activity converting alpha-ketoglutarate to 2-hydroxyglutarate

    Fiehn, Oliver; Showalter, Megan Reed; Schaner-Tooley, Christine E

    2016-01-01

    The Reproducibility Project: Cancer Biology seeks to address growing concerns about reproducibility in scientific research by conducting replications of selected experiments from a number of high-profile papers in the field of cancer biology. The papers, which were published between 2010 and 2012, were selected on the basis of citations and Altmetric scores (Errington et al., 2014). This Registered Report describes the proposed replication plan of key experiments from “The common feature of leukemia-associated IDH1 and IDH2 mutations is a neomorphic enzyme activity converting alpha-ketoglutarate to 2-hydroxyglutarate” by Ward and colleagues, published in Cancer Cell in 2010 (Ward et al., 2010). The experiments that will be replicated are those reported in Figures 2, 3 and 5. Ward and colleagues demonstrate the mutations in isocitrate dehydrogenase 2 (IDH2), commonly found in acute myeloid leukemia (AML), abrogate the enzyme’s wild-type activity and confer to the mutant neomorphic activity that produces the oncometabolite 2-hydroxyglutarate (2-HG) (Figures 2 and 3). They then show that elevated levels of 2-HG are correlated with mutations in IDH1 and IDH2 in AML patient samples (Figure 5). The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange and the results of the replications will be published by eLife. DOI: http://dx.doi.org/10.7554/eLife.12626.001 PMID:26943899

  1. In Vitro and In Vivo Assessment of Angiotensin-Converting Enzyme (ACE) Inhibitory Activity of Fermented Soybean Milk by Lactobacillus casei Strains.

    Bao, Zhijie; Chi, Yujie

    2016-08-01

    Angiotensin-converting enzyme (ACE) inhibitory activity of fermented soybean milk (FSM) by Lactobacillus casei strains in vitro was investigated in this study. Effects of fermented soybean milk administration by gavage on systolic blood pressure and diastolic blood pressure was also evaluated in spontaneously hypertensive rats (SHR) rats and Wistar-Kyoto (WKY) rats. Results showed that, CICC 20280 and CICC 23184 FSM showed high ACE inhibitory activity in vitro test and ACE inhibitory activity of CICC 23184 FSM was higher than CICC 20280 FSM. The bioactive substances of FSM were peptide and γ-aminobutyric acid (GABA). Their contents in CICC 20280 FSM and CICC 23184 FSM were 3.97 ± 0.67 mg/ml (peptide), 1.71 ± 0.36 mg/ml (GABA) and 5.17 ± 0.22 mg/ml (peptide), 1.57 ± 0.21 mg/ml (GABA), respectively. Moreover, CICC 20280 and CICC 23184 FSM administration by gavage could effectively lower the blood pressure of SHR to a normal level, while there was no effect on blood pressure of WKY rats. This result indicated that the bioactive substances could play an antihypertensive role when the blood pressure was not within the normal levels (high levels). PMID:27139252

  2. Angiotensin I-converting enzyme (ACE) inhibitory activity and structural properties of oven- and freeze-dried protein hydrolysate from fresh water fish (Cirrhinus mrigala).

    Elavarasan, K; Shamasundar, B A; Badii, Faraha; Howell, Nazlin

    2016-09-01

    The angiotensin I-converting enzyme (ACE) inhibitory activity and structural properties of oven-dried (OD-FPH) and freeze-dried (FD-FPH) protein hydrolysates derived from fresh water fish (Cirrhinus mrigala) muscle, using papain, were investigated. Amino acid profiles indicated a higher proportion of hydrophobic residues in OD-FPH and hydrophilic residues in FD-FPH samples. Fourier transform infrared (FT-IR) spectra revealed random coil structure in OD-FPH and β-sheet in FD-FPH samples. The approximate molecular weight of peptides in OD-FPH and FD-FPH was in the range of 7030-339Da. The IC50 values for ACE inhibition by OD-FPH and FD-FPH samples were found to be 1.15 and 1.53mg of proteinml(-1), respectively. The ACE-inhibitory activity of OD-FPH was more stable (during sequential digestion, using pepsin and pancreatin) than that of FD-FPH sample. The study suggested that the ACE inhibitory activity of protein hydrolysate was not affected by oven-drying. PMID:27041318

  3. Converting redox signaling to apoptotic activities by stress-responsive regulators HSF1 and NRF2 in fenretinide treated cancer cells.

    Kankan Wang

    Full Text Available BACKGROUND: Pharmacological intervention of redox balance in cancer cells often results in oxidative stress-mediated apoptosis, attracting much attention for the development of a new generation of targeted therapy in cancer. However, little is known about mechanisms underlying the conversion from oxidative signaling to downstream activities leading cells to death. METHODOLOGY/PRINCIPAL FINDINGS: We here report a systematic detection of transcriptome changes in response to oxidative signals generated in leukemia cells upon fenretinide treatment, implicating the occurrence of numerous stress-responsive events during the fenretinide induced apoptosis, such as redox response, endoplasmic reticulum stress/unfolded protein response, translational repression and proteasome activation. Moreover, the configuration of these relevant events is primarily orchestrated by stress responsive transcription factors, as typically highlighted by NF-E2-related factor-2 (NRF2 and heat shock factor 1 (HSF1. Several lines of evidence suggest that the coordinated regulation of these transcription factors and thus their downstream genes are involved in converting oxidative signaling into downstream stress-responsive events regulating pro-apoptotic and apoptotic activities at the temporal and spatial levels, typifying oxidative stress-mediated programmed death rather than survival in cancer cells. CONCLUSIONS/SIGNIFICANCE: This study provides a roadmap for understanding oxidative stress-mediated apoptosis in cancer cells, which may be further developed into more sophisticated therapeutic protocols, as implicated by synergistic induction of cell apoptosis using proteasome inhibitors with fenretinide.

  4. Angiotensin I-Converting Enzyme inhibitory and antioxidant activities and surfactant properties of protein hydrolysates as obtained of Amaranthus hypochondriacus L. grain.

    Soriano-Santos, J; Escalona-Buendía, H

    2015-04-01

    Even though some research has been carried out on surfactant properties of amaranth protein hydrolysates, their bio-functionality has not been studied yet. In this work amaranth grain Alb 1 and Glob were hydrolyzed (Alb 1H, Glob H) and foams and emulsions at optimal conditions (t, E/S, pH5) were prepared in order to assess techno-functional properties such as foaming (F) and emulsifying (E) (capacity (C) and stability (S)). FC and EC were much better for Glob H than for Alb H. Angiotensin I-converting enzyme-inhibitory activity was higher for Alb 1H (roughly 50 %) than that of Glob H (roughly 30 %). Scavenging of radicals activity (DPPH· or ABTS· (+) ) of Alb 1H and Glob H, at 2 mg/mL, was similar (approx. 40 %), but lower than Alb 1 (approx. 70 %), which was the best antioxidant. The low reducing power showed that hydrolysates barely donate an electron or hydrogen. Chelating activity on Cu(2+) was lower than that exhibited by Fe(2+,) which was remarkable, approx. 80 % as long as DH% > 10 %, where hydrolysates displayed high solubility (Alb 1H = 85 %, Glob H = 70 %) because of occurrence of 1-10 kDa peptides. Amaranth foams and emulsions prepared with protein hydrolysates have a potential as a nutraceutical food. PMID:25829587

  5. Short communication: Potential of Fresco-style cheese whey as a source of protein fractions with antioxidant and angiotensin-I-converting enzyme inhibitory activities.

    Tarango-Hernández, S; Alarcón-Rojo, A D; Robles-Sánchez, M; Gutiérrez-Méndez, N; Rodríguez-Figueroa, J C

    2015-11-01

    Recently, traditional Mexican Fresco-style cheese production has been increasing, and the volume of cheese whey generated represents a problem. In this study, we investigated the chemical composition of Fresco-style cheese wheys and their potential as a source of protein fractions with antioxidant and angiotensin-I-converting enzyme (ACE)-inhibitory activities. Three samples from Fresco, Panela, and Ranchero cheeses whey were physicochemically characterized. Water-soluble extracts were fractionated to obtain whey fractions with different molecular weights: 10-5, 5-3, 3-1 and protein, ash, and dry matter contents (% wt/wt) in the different Fresco-style cheese wheys. All whey fractions had antioxidant and ACE-inhibitory activities. The 10-5 kDa whey fraction of Ranchero cheese had the highest Trolox equivalent antioxidant capacity (0.62 ± 0.00 mM), and the 3-1 kDa Panela and Fresco cheese whey fractions showed the highest ACE-inhibitory activity (0.57 ± 0.02 and 0.59 ± 0.04 μg/mL 50%-inhibitory concentration values, respectively). These results suggest that Fresco-style cheese wheys may be a source of protein fractions with bioactivity, and thus could be useful ingredients in the manufacture of functional foods with increased nutritional value. PMID:26364114

  6. Angiotensin-converting enzyme inhibition prevents myocardial infarction-induced increase in renal cortical cGMP and cAMP phosphodiesterase activities.

    Clauss, François; Charloux, Anne; Piquard, François; Doutreleau, Stéphane; Talha, Samy; Zoll, Joffrey; Lugnier, Claire; Geny, Bernard

    2015-08-01

    We investigated whether myocardial infarction (MI) enhances renal phosphodiesterases (PDE) activities, investigating particularly the relative contribution of PDE1-5 isozymes in total PDE activity involved in both cGMP and cAMP pathways, and whether angiotensin-converting enzyme inhibition (ACEi) decreases such renal PDE hyperactivities. We also investigated whether ACEi might thereby improve atrial natriuretic peptide (ANP) efficiency. We studied renal cortical PDE1-5 isozyme activities in sham (SH)-operated, MI rats and in MI rats treated with perindopril (ACEi) 1 month after coronary artery ligation. Circulating atrial natriuretic peptide (ANP), its second intracellular messenger cyclic guanosine monophosphate (cGMP) and cGMP/ANP ratio were also determined. Cortical cGMP-PDE2 (80.3 vs. 65.1 pmol/min/mg) and cGMP-PDE1 (50.7 vs. 30.1 pmol/min/mg), and cAMP-PDE2 (161 vs. 104.1 pmol/min/mg) and cAMP-PDE4 (307.5 vs. 197.2 pmol/min/mg) activities were higher in MI than in SH rats. Despite increased ANP plasma level, ANP efficiency tended to be decreased in MI compared to SH rats. Perindopril restored PDE activities and tended to improve ANP efficiency in MI rats. One month after coronary ligation, perindopril treatment of MI rats prevents the increase in renal cortical PDE activities. This may contribute to increase renal ANP efficiency in MI rats. PMID:25939307

  7. Angiotensin I-converting enzyme (ACE) inhibitory activities of sardinelle (Sardinella aurita) by-products protein hydrolysates obtained by treatment with microbial and visceral fish serine proteases.

    Bougatef, Ali; Nedjar-Arroume, Naima; Ravallec-Plé, Rozenn; Leroy, Yves; Guillochon, Didier; Barkia, Ahmed; Nasri, Moncef

    2008-11-15

    The angiotensin I-converting enzyme (ACE) inhibitory activities of protein hydrolysates prepared from heads and viscera of sardinelle (Sardinella aurita) by treatment with various proteases were investigated. Protein hydrolysates were obtained by treatment with Alcalase(®), chymotrypsin, crude enzyme preparations from Bacillus licheniformis NH1 and Aspergillus clavatus ES1, and crude enzyme extract from sardine (Sardina pilchardus) viscera. All hydrolysates exhibited inhibitory activity towards ACE. The alkaline protease extract from the viscera of sardine produced hydrolysate with the highest ACE inhibitory activity (63.2±1.5% at 2mg/ml). Further, the degrees of hydrolysis and the inhibitory activities of ACE increased with increasing proteolysis time. The protein hydrolysate generated with alkaline proteases from the viscera of sardine was then fractionated by size exclusion chromatography on a Sephadex G-25 into eight major fractions (P1-P8). Biological functions of all fractions were assayed, and P4 was found to display a high ACE inhibitory activity. The IC50 values for ACE inhibitory activities of sardinelle by-products protein hydrolysates and fraction P4 were 1.2±0.09 and 0.81±0.013mg/ml, respectively. Further, P4 showed resistance to in vitro digestion by gastrointestinal proteases. The amino acid analysis by GC/MS showed that P4 was rich in phenylalanine, arginine, glycine, leucine, methionine, histidine and tyrosine. The added-value of sardinelle by-products may be improved by enzymatic treatment with visceral serine proteases from sardine. PMID:26047434

  8. Increasing of Reliability of Converter

    Trebuňa, F.

    2006-01-01

    Full Text Available The innovative activities in steel production invoke exploitation of new machines with the higher production capacity and productivity of labor. The paper deals with deformation and stress analysis of carrying parts of converter pedestal on the base of which the proposals and supporting measures were made that had the aim to increase reliability of the converter during steel production. This was achieved by lifespan prolongation of anchor and connecting bolts of converter pedestal, by change of stiffness of connected elements as well as by correction of nuts of bolted connections. The realization of structural changes decreased loading amplitudes and consequently the vibrations of pedestal. Solution was verified by numerical and experimental procedures of mechanics.

  9. In silico and in vitro analyses of the angiotensin-I converting enzyme inhibitory activity of hydrolysates generated from crude barley (Hordeum vulgare) protein concentrates.

    Gangopadhyay, Nirupama; Wynne, Kieran; O'Connor, Paula; Gallagher, Eimear; Brunton, Nigel P; Rai, Dilip K; Hayes, Maria

    2016-07-15

    Angiotensin-I-converting enzyme (ACE-I) plays a key role in control of hypertension, and type-2 diabetes mellitus, which frequently co-exist. Our current work utilised in silico methodologies and peptide databases as tools for predicting release of ACE-I inhibitory peptides from barley proteins. Papain was the enzyme of choice, based on in silico analysis, for experimental hydrolysis of barley protein concentrate, which was performed at the enzyme's optimum conditions (60 °C, pH 6.0) for 24 h. The generated hydrolysate was subjected to molecular weight cut-off (MWCO) filtration, following which the non-ultrafiltered hydrolysate (NUFH), and the generated 3 kDa and 10 kDa MWCO filtrates were assessed for their in vitro ACE-I inhibitory activities. The 3 kDa filtrate (1 mg/ml), that demonstrated highest ACE-I inhibitory activity of 70.37%, was characterised in terms of its peptidic composition using mass spectrometry and 1882 peptides derived from 61 barley proteins were identified, amongst which 15 peptides were selected for chemical synthesis based on their predicted ACE-I inhibitory properties. Of the synthesized peptides, FQLPKF and GFPTLKIF were most potent, demonstrating ACE-I IC50 values of 28.2 μM and 41.2 μM respectively. PMID:26948626

  10. Niemann-Pick Type C2 Protein Mediates Hepatic Stellate Cells Activation by Regulating Free Cholesterol Accumulation

    Yuh-Ching Twu

    2016-07-01

    Full Text Available In chronic liver diseases, regardless of their etiology, the development of fibrosis is the first step toward the progression to cirrhosis, portal hypertension, and hepatocellular carcinoma. Hepatic stellate cells (HSCs are the main profibrogenic cells that promote the pathogenesis of liver fibrosis, and so it is important to identify the molecules that regulate HSCs activation and liver fibrosis. Niemann-Pick type C2 (NPC2 protein plays an important role in the regulation of intracellular cholesterol homeostasis by directly binding with free cholesterol. However, the roles of NPC2 in HSCs activation and liver fibrosis have not been explored in detail. Since a high-cholesterol diet exacerbates liver fibrosis progression in both rodents and humans, we propose that the expression of NPC2 affects free cholesterol metabolism and regulates HSCs activation. In this study, we found that NPC2 is decreased in both thioacetamide- and carbon tetrachloride-induced liver fibrosis tissues. In addition, NPC2 is expressed in quiescent HSCs, but its activation status is down-regulated. Knockdown of NPC2 in HSC-T6 cells resulted in marked increases in transforming growth factor-β1 (TGF-β1-induced collagen type 1 α1 (Col1a1, α-smooth muscle actin (α-SMA expression, and Smad2 phosphorylation. In contrast, NPC2 overexpression decreased TGF-β1-induced HSCs activation. We further demonstrated that NPC2 deficiency significantly increased the accumulation of free cholesterol in HSCs, increasing Col1a1 and α-SMA expression and activating Smad2, and leading to sensitization of HSCs to TGF-β1 activation. In contrast, overexpression of NPC2 decreased U18666A-induced free cholesterol accumulation and inhibited the subsequent HSCs activation. In conclusion, our study has demonstrated that NPC2 plays an important role in HSCs activation by regulating the accumulation of free cholesterol. NPC2 overexpression may thus represent a new treatment strategy for liver fibrosis.