Radiation-Tolerant DC-DC Converters

NASA Technical Reports Server (NTRS)

Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

2012-01-01

A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

Polymerization kinetics of experimental bioactive composites containing bioactive glass.

PubMed

Par, Matej; Tarle, Zrinka; Hickel, Reinhard; Ilie, Nicoleta

2018-06-21

To investigate the polymerization kinetics and the degree of conversion (DC) of experimental resin composites with varying amount of bioactive glass 45S5 (BG). Experimental resin composites based on a photo-curable Bis-GMA/TEGDMA resin system were prepared. The composite series contained 0, 5, 10, 20, and 40 wt% of BG and reinforcing fillers up to the total filler amount of 70 wt%. Composite specimens were light cured with 1,219 mW/cm 2 for 20 or 40 s and their DC was monitored during 5 min at the data collection rate of 2 s -1 using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The 5-min DC values for experimental composites were in the range of 42.4-55.9% and 47.3-57.9% for curing times of 20 and 40 s, respectively. The differences in the 5-min DC between curing times of 20 s or 40 s became more pronounced in materials with higher BG amount. Within both curing times, a decreasing trend of the 5-min DC values was observed with the increasing percentage of BG fillers. The maximum polymerization rate also decreased consistently with the increasing BG amount. Unsilanized BG fillers showed a dose-dependent inhibitory effect on polymerization rate and the DC. Extending the curing time from 20 to 40 s showed a limited potential to improve the DC of composites with higher BG amount. The observed inhibitory effect of BG fillers on the polymerization of resin composites may have a negative influence on mechanical properties and biocompatibility. Copyright © 2018. Published by Elsevier Ltd.

Design of energy-storage reactors for single-winding constant-frequency dc-to-dc converters operating in the discontinuous-reactor-current mode

NASA Technical Reports Server (NTRS)

Chen, D. Y.; Owen, H. A., Jr.; Wilson, T. G.

1980-01-01

This paper presents an algorithm and equations for designing the energy-storage reactor for dc-to-dc converters which are constrained to operate in the discontinuous-reactor-current mode. This design procedure applied to the three widely used single-winding configurations: the voltage step-up, the current step-up, and the voltage-or-current step-up converters. A numerical design example is given to illustrate the use of the design algorithm and design equations.

Dual centrifugation - A new technique for nanomilling of poorly soluble drugs and formulation screening by an DoE-approach.

PubMed

Hagedorn, Martin; Bögershausen, Ansgar; Rischer, Matthias; Schubert, Rolf; Massing, Ulrich

2017-09-15

The development of nanosuspensions of poorly soluble APIs takes a lot of time and high amount of active material is needed. In this publication the use of dual centrifugation (DC) for an effective and rapid API-nanomilling is described for the first time. DC differs from normal centrifugation by an additional rotation of the samples during centrifugation, resulting in a very fast and powerful movement of the samples inside the vials, which - in combination with milling beads - result in effective milling. DC-nanomilling was compared to conventional wet ball milling and results in same or even smaller particle sizes. Also drug concentrations up to 40% can be processed. The process is fast (typical 90min) and the temperature can be controlled. DC-nanomilling appears to be very gentle, experiments showed no change of the crystal structure during milling. Since batch sizes are very small (100-1000mg) and since 40 sample vials can be processed in parallel, DC is ideal for the screening of suitable polymer/surfactant combinations. Fenofibrate was used to investigate DC-nanomilling for formulation screening by applying a DoE-approach. The presented data also show that the results of DC-nanomilling experiments are highly comparable to the results obtained by common agitator mills. Copyright © 2017 Elsevier B.V. All rights reserved.

Polymerization kinetics and impact of post polymerization on the Degree of Conversion of bulk-fill resin-composite at clinically relevant depth.

PubMed

Al-Ahdal, Khold; Ilie, Nicoleta; Silikas, Nick; Watts, David C

2015-10-01

Since bulk-fill (BF) resin composites should cure efficiently to a depth up to 4mm, the aim of the study was to determine the time-dependence of degree of conversion (DC) at that depth during 24h post-irradiation. Eight representative BF resin composites were studied [x-tra base (XTB), Venus Bulk Fill (VBF), Tetric EvoCeram Bulk Fill (TECBF), Sonic Fill (SF), Filtek Bulk Fill (FBF), everX Posterior (eXP), Beautifil-Bulk Flowable (BBF), Beautifil-Bulk Restorative (BBR)]. Specimens were fabricated in white Delrin moulds of 4mm height and 5mm internal diameter directly on an attenuated total reflectance (ATR) accessory attachment of an (FTIR) spectrometer (Nicolet iS50, Thermo Fisher, Madison, USA). Upper specimen surfaces were irradiated in situ for 20 s with an LED curing unit (Elipar S10 with average tip irradiance of 1200 mW/cm(2)). Spectra from the lower surface were recorded continuously in real-time for 5 min and then at 30 and 60 min and 24h post irradiation. Mean ranges of DC4mm (%) of the materials at 4mm depth were 39-67; 48-75; 45-74; and 50-72 at 5, 30 and 60 min and 24h respectively. DCs for XTB, VBF, TECBF, FBF, BBR increased significantly 30 min after irradiation (p<0.05) and were not affected by subsequent time up to 24h (p>0.05). DC for SF was not affected by subsequent time after 5 min (p>0.05). For eXP and BBF, DC increased 24h after irradiation (p<0.05). The data were described by the superposition of two exponential functions characterising the gel phase (described by parameters a, b) and the glass phase (described by parameters c and d). Post polymerization impact of bulk-fill composites is material dependent. Five materials exhibited their maximum DC4mm already 30 min after starting the irradiation while DC4mm for two materials optimized after 24h. BF materials were found to exhibit after 24h a DC between 50 and 72% at 4mm depth under the stated irradiation conditions. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Dendritic cells for active immunotherapy: optimizing design and manufacture in order to develop commercially and clinically viable products.

PubMed

Nicolette, C A; Healey, D; Tcherepanova, I; Whelton, P; Monesmith, T; Coombs, L; Finke, L H; Whiteside, T; Miesowicz, F

2007-09-27

Dendritic cell (DC) active immunotherapy is potentially efficacious in a broad array of malignant disease settings. However, challenges remain in optimizing DC-based therapy for maximum clinical efficacy within manufacturing processes that permit quality control and scale-up of consistent products. In this review we discuss the critical issues that must be addressed in order to optimize DC-based product design and manufacture, and highlight the DC based platforms currently addressing these issues. Variables in DC-based product design include the type of antigenic payload used, DC maturation steps and activation processes, and functional assays. Issues to consider in development include: (a) minimizing the invasiveness of patient biological material collection; (b) minimizing handling and manipulations of tissue at the clinical site; (c) centralized product manufacturing and standardized processing and capacity for commercial-scale production; (d) rapid product release turnaround time; (e) the ability to manufacture sufficient product from limited starting material; and (f) standardized release criteria for DC phenotype and function. Improvements in the design and manufacture of DC products have resulted in a handful of promising leads currently in clinical development.

Analysis of high voltage step-up nonisolated DC-DC boost converters

NASA Astrophysics Data System (ADS)

Alisson Alencar Freitas, Antônio; Lessa Tofoli, Fernando; Junior, Edilson Mineiro Sá; Daher, Sergio; Antunes, Fernando Luiz Marcelo

2016-05-01

A high voltage step-up nonisolated DC-DC converter based on coupled inductors suitable to photovoltaic (PV) systems applications is proposed in this paper. Considering that numerous approaches exist to extend the voltage conversion ratio of DC-DC converters that do not use transformers, a detailed comparison is also presented among the proposed converter and other popular topologies such as the conventional boost converter and the quadratic boost converter. The qualitative analysis of the coupled-inductor-based topology is developed so that a design procedure can be obtained, from which an experimental prototype is implemented to validate the theoretical assumptions.

Power supply of autonomous systems using solar modules

NASA Astrophysics Data System (ADS)

Yurchenko, A. V.; Zotov, L. G.; Mekhtiev, A. D.; Yugai, V. V.; Tatkeeva, G. G.

2015-04-01

The article shows the methods of constructing autonomous decentralized energy systems from solar modules. It shows the operation of up DC inverter. It demonstrates the effectiveness of DC inverters with varying structure. The system has high efficiency and low level of conductive impulse noise and at the same time the system is practically feasible. Electrical processes have been analyzed to determine the characteristics of operating modes of the main circuit elements. Recommendations on using the converters have been given.

Real-time monitoring of human blood-brain barrier disruption

PubMed Central

Kiviniemi, Vesa; Korhonen, Vesa; Kortelainen, Jukka; Rytky, Seppo; Keinänen, Tuija; Tuovinen, Timo; Isokangas, Matti; Sonkajärvi, Eila; Siniluoto, Topi; Nikkinen, Juha; Alahuhta, Seppo; Tervonen, Osmo; Turpeenniemi-Hujanen, Taina; Myllylä, Teemu; Kuittinen, Outi; Voipio, Juha

2017-01-01

Chemotherapy aided by opening of the blood-brain barrier with intra-arterial infusion of hyperosmolar mannitol improves the outcome in primary central nervous system lymphoma. Proper opening of the blood-brain barrier is crucial for the treatment, yet there are no means available for its real-time monitoring. The intact blood-brain barrier maintains a mV-level electrical potential difference between blood and brain tissue, giving rise to a measurable electrical signal at the scalp. Therefore, we used direct-current electroencephalography (DC-EEG) to characterize the spatiotemporal behavior of scalp-recorded slow electrical signals during blood-brain barrier opening. Nine anesthetized patients receiving chemotherapy were monitored continuously during 47 blood-brain barrier openings induced by carotid or vertebral artery mannitol infusion. Left or right carotid artery mannitol infusion generated a strongly lateralized DC-EEG response that began with a 2 min negative shift of up to 2000 μV followed by a positive shift lasting up to 20 min above the infused carotid artery territory, whereas contralateral responses were of opposite polarity. Vertebral artery mannitol infusion gave rise to a minimally lateralized and more uniformly distributed slow negative response with a posterior-frontal gradient. Simultaneously performed near-infrared spectroscopy detected a multiphasic response beginning with mannitol-bolus induced dilution of blood and ending in a prolonged increase in the oxy/deoxyhemoglobin ratio. The pronounced DC-EEG shifts are readily accounted for by opening and sealing of the blood-brain barrier. These data show that DC-EEG is a promising real-time monitoring tool for blood-brain barrier disruption augmented drug delivery. PMID:28319185

A fully integrated, wide-load-range, high-power-conversion-efficiency switched capacitor DC-DC converter with adaptive bias comparator for ultra-low-power power management integrated circuit

NASA Astrophysics Data System (ADS)

Asano, Hiroki; Hirose, Tetsuya; Kojima, Yuta; Kuroki, Nobutaka; Numa, Masahiro

2018-04-01

In this paper, we present a wide-load-range switched-capacitor DC-DC buck converter with an adaptive bias comparator for ultra-low-power power management integrated circuit. The proposed converter is based on a conventional one and modified to operate in a wide load range by developing a load current monitor used in an adaptive bias comparator. Measurement results demonstrated that our proposed converter generates a 1.0 V output voltage from a 3.0 V input voltage at a load of up to 100 µA, which is 20 times higher than that of the conventional one. The power conversion efficiency was higher than 60% in the load range from 0.8 to 100 µA.

Pressure effect on spin-glass behavior in Ce0.9Er0.1Al2

NASA Astrophysics Data System (ADS)

Wakiya, Kazuhei; Hu, Guanghui; Fuseya, Ryohei; Ohashi, Masashi; Uehara, Masatomo; Umehara, Izuru

2018-05-01

The dc magnetization and ac susceptibility of the Laves phase compound Ce0.9Er0.1Al2 have been measured at ambient and high pressures up to 1.1 GPa. The ac susceptibility shows a peak at around Tf 2.5 K, and Tf shifts to higher temperatures with an increase in the measuring frequency. Below Tf, the zero-field-cooled (ZFC) and field-cooled (FC) dc magnetizations separate from each other. Furthermore, long-time magnetic relaxation behavior is observed. These results indicate that a spin-glass state is formed below Tf. We found that the Tf determined by dc magnetization measurement decreases with an increase in pressure.

High-voltage testing of a 500-kV dc photocathode electron gun.

PubMed

Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Muto, Toshiya; Yamamoto, Masahiro; Honda, Yosuke; Miyajima, Tsukasa; Iijima, Hokuto; Kuriki, Masao; Kuwahara, Makoto; Okumi, Shoji; Nakanishi, Tsutomu

2010-03-01

A high-voltage dc photocathode electron gun was successfully conditioned up to a voltage of 550 kV and a long-time holding test for 8 h was demonstrated at an acceleration voltage of 500 kV. The dc photocathode electron gun is designed for future light sources based on energy-recovery linac and consists of a Cockcroft-Walton generator, a segmented cylindrical ceramic insulator, guard-ring electrodes, a support-rod electrode, a vacuum chamber, and a pressurized insulating gas tank. The segmented cylindrical ceramic insulator and the guard-ring electrodes were utilized to prevent any damage to the insulator from electrons emitted by the support-rod electrode.

Theory of controlling band-width broadening in terahertz sideband generation in semiconductors by a direct current electric field

NASA Astrophysics Data System (ADS)

Liu, Houquan; Zhang, Xingchu

2017-03-01

In a semiconductor, optically excited electron-hole pairs, driven by a strong terahertz (THz) field, can recombine to create THz sidebands in the optical spectrum. The sideband spectrum exhibits a "plateau" up to a cutoff frequency of 3.17Up, where Up is the ponderomotive energy. In this letter, we predict that the bandwidth of this sideband spectrum plateau can be broadened by applying an additional direct-current (DC) electric field. We find that if applying a DC field of EDC=0.2ETHz (where EDC and ETHz are the amplitudes of the DC field and THz field, respectively), the sideband spectrum presents three plateaus with 5.8Up, 10.05Up and 16Up being the cutoff frequencies of the first, second and third plateaus, respectively. This bandwidth broadening occurs because the DC field can increase the kinetic energy that an electron-hole pair can gain from the THz field. This effect means that the bandwidth of the sideband spectrum can be controlled flexibly by changing the DC field, thereby facilitating the ultrafast electro-optical applications of THz sideband generation.

Long-Lead Prediction of the 2015 Fire and Haze Episode in Indonesia

NASA Astrophysics Data System (ADS)

Shawki, Dilshad; Field, Robert D.; Tippett, Michael K.; Saharjo, Bambang Hero; Albar, Israr; Atmoko, Dwi; Voulgarakis, Apostolos

2017-10-01

We conducted a case study of National Centers for Environmental Prediction Climate Forecast System version 2 seasonal model forecast performance over Indonesia in predicting the dry conditions in 2015 that led to severe fire, in comparison to the non-El Niño dry season conditions of 2016. Forecasts of the Drought Code (DC) component of Indonesia's Fire Danger Rating System were examined across the entire equatorial Asia region and for the primary burning regions within it. Our results show that early warning lead times of high observed DC in September and October 2015 varied considerably for different regions. High DC over Southern Kalimantan and Southern New Guinea were predicted with 180 day lead times, whereas Southern Sumatra had lead times of up to only 60 days, which we attribute to the absence in the forecasts of an eastward decrease in Indian Ocean sea surface temperatures. This case study provides the starting point for longer-term evaluation of seasonal fire danger rating forecasts over Indonesia.

EBI1/CCR7 is a new member of dendritic cell chemokine receptor that is up-regulated upon maturation.

PubMed

Yanagihara, S; Komura, E; Nagafune, J; Watarai, H; Yamaguchi, Y

1998-09-15

Dendritic cells (DC) that are stimulated with inflammatory mediators can maturate and migrate from nonlymphoid tissues to lymphoid organs to initiate T cell-mediated immune responses. This migratory step is closely related to the maturation of the DC. In an attempt to identify chemokine receptors that might influence migration and are selectively expressed in mature DC, we have discovered that the chemokine receptor, EBI1/CCR7, is strikingly up-regulated upon maturation in three distinct culture systems: 1) mouse bone marrow-derived DC, 2) mouse epidermal Langerhans cells, and 3) human monocyte-derived DC. The EBI1/CCR7 expressed in mature DC is functional because ELC/MIP-3beta, recently identified as a ligand of EBI1/CCR7, induces a rise in intracellular free calcium concentrations and directional migration of human monocyte-derived mature DC (HLA-DRhigh, CD1a(low), CD14-, CD25+, CD83+, and CD86high) in a dose-dependent manner, but not of immature DC (HLA-DRlow, CD1a(high), CD14-, CD25-, CD83-, and CD86-). In contrast, macrophage inflammatory protein-1alpha (MIP-1alpha), monocyte chemotactic protein-3 (MCP-3), and RANTES are active on immature DC but not on mature DC. Thus, it seems likely that MIP-1alpha, MCP-3, and RANTES can mediate the migration of immature DC located in peripheral sites, whereas ELC/MIP-3beta can direct the migration of Ag-carrying DC from peripheral inflammatory sites, where DC are stimulated to up-regulate the expression of EBI1/CCR7, to lymphoid organs. It is postulated that different chemokines and chemokine receptors are involved in DC migration in vivo, depending on the maturation state of DC.

AVR Microcontroller-based automated technique for analysis of DC motors

NASA Astrophysics Data System (ADS)

Kaur, P.; Chatterji, S.

2014-01-01

This paper provides essential information on the development of a 'dc motor test and analysis control card' using AVR series ATMega32 microcontroller. This card can be interfaced to PC and calculates parameters like motor losses, efficiency and plot characteristics for dc motors. Presently, there are different tests and methods available to evaluate motor parameters, but a single and universal user-friendly automated set-up has been discussed in this paper. It has been accomplished by designing a data acquisition and SCR bridge firing hardware based on AVR ATMega32 microcontroller. This hardware has the capability to drive the phase-controlled rectifiers and acquire real-time values of current, voltage, temperature and speed of motor. Various analyses feasible with the designed hardware are of immense importance for dc motor manufacturers and quality-sensitive users. Authors, through this paper aim to provide details of this AVR-based hardware which can be used for dc motor parameter analysis and also for motor control applications.

Fast-response free-running dc-to-dc converter employing a state-trajectory control law

NASA Technical Reports Server (NTRS)

Huffman, S. D.; Burns, W. W., III; Wilson, T. G.; Owen, H. A., Jr.

1977-01-01

A recently proposed state-trajectory control law for a family of energy-storage dc-to-dc converters has been implemented for the voltage step-up configuration. Two methods of realization are discussed; one employs a digital processor and the other uses analog computational circuits. Performance characteristics of experimental voltage step-up converters operating under the control of each of these implementations are reported and compared to theoretical predictions and computer simulations.

MicroRNA-Mediated Down-Regulation of M-CSF Receptor Contributes to Maturation of Mouse Monocyte-Derived Dendritic Cells

PubMed Central

Riepsaame, Joey; van Oudenaren, Adri; den Broeder, Berlinda J. H.; van IJcken, Wilfred F. J.; Pothof, Joris; Leenen, Pieter J. M.

2013-01-01

Dendritic cell (DC) maturation is a tightly regulated process that requires coordinated and timed developmental cues. Here we investigate whether microRNAs are involved in this process. We identify microRNAs in mouse GM-CSF-generated, monocyte-related DC (GM-DC) that are differentially expressed during both spontaneous and LPS-induced maturation and characterize M-CSF receptor (M-CSFR), encoded by the Csf1r gene, as a key target for microRNA-mediated regulation in the final step toward mature DC. MicroRNA-22, -34a, and -155 are up-regulated in mature MHCIIhi CD86hi DC and mediate Csf1r mRNA and protein down-regulation. Experimental inhibition of Csf1r-targeting microRNAs in vitro results not only in sustained high level M-CSFR protein expression but also in impaired DC maturation upon stimulation by LPS. Accordingly, over-expression of Csf1r in GM-DC inhibits terminal differentiation. Taken together, these results show that developmentally regulated microRNAs control Csf1r expression, supplementing previously identified mechanisms that regulate its transcription and protein surface expression. Furthermore, our data indicate a novel function for Csf1r in mouse monocyte-derived DC, showing that down-regulation of M-CSFR expression is essential for final DC maturation. PMID:24198819

Inpatient hospital burden of hepatitis C-diagnosed patients with decompensated cirrhosis.

PubMed

McDonald, Scott A; Innes, Hamish A; Aspinall, Esther J; Hayes, Peter C; Alavi, Maryam; Valerio, Heather; Goldberg, David J; Hutchinson, Sharon J

2017-12-30

To describe the burden on inpatient hospital resources over time from patients diagnosed with hepatitis C virus (HCV) infection and who have reached the decompensated stage of cirrhosis (DC), as existing estimates of hospital stay in these patients are limited. A retrospective longitudinal dataset was formed via record-linkage between the national HCV diagnosis database and inpatient/daycase hospitalisation and death registers in Scotland. The study population consisted of HCV-diagnosed patients with a first DC admission in 1996-2013, with follow-up available until 31 May 2014. We investigated and quantified the mean cumulative length of hospital stay, distributions over discharge diagnosis categories, and trends in admission rates. Among our study population (n = 1543), we identified 10 179 admissions with any diagnosis post-first DC admission. Between 1996 and 2013 there was a 16-fold rise in annual total admissions (from 112 to 1791) and an 11-fold rise in hospital stay (719-8045). When restricting minimum possible follow-up to 2 years, DC patients (n = 1312) had an overall admission rate of 7.3 per person-year, and spent on average 43 days (26 days during first 6 months) in hospital; for all liver-related, liver-related other than HCC/DC, and non-liver related only admissions, this was 39, 14, and 5 days respectively. HCV-infected DC patients impose a considerable inpatient hospital burden, mostly from DC- and other liver-related admissions, but also from admissions associated with non-liver comorbidities. Estimates will be useful for monitoring the impact of prevention and treatment, and for computing the cost-effectiveness of new therapies. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Decoy Receptor 3 (DcR3) as a Biomarker of Tumor Deterioration in Female Reproductive Cancers: A Meta-Analysis.

PubMed

Jiang, Mengtong; Lin, Xiaomiao; He, Rongquan; Lin, Xinggu; Liang, Lu; Tang, Ruixue; Xiong, Dandan; Wei, Kanglai; Dang, Yiwu; Feng, Zhenbo; Chen, Gang

2016-06-01

BACKGROUND DcR3 (decoy receptor 3) has been proposed be involved in development and prognosis of female reproductive cancers, including cervical cancer, ovarian cancer, and breast cancer. The purpose of this meta-analysis was to explore the evidence for the correlation between DcR3 and the clinicopathological characteristics, as well as the overall survival time, in female reproductive cancers. MATERIAL AND METHODS Relevant studies were searched for in PubMed, Wiley Online Library, Web of Science, Science Direct, Cochrane Central Register of Controlled Trials, Google Scholar, EMBASE, Ovid, LILACS, Chinese CNKI, Chong Qing VIP, Wan Fang, and China Biology Medicine disc up to 30 September 2015. Data on the relationship between DcR3 expression and TNM stage, differentiation, lymph node metastasis, age, and overall survival time were extracted. Pooled odds ratios (ORs) and 95% CIs (confidence intervals) were estimated by forest plot. RESULTS Twelve studies with 1127 patients met the inclusion criteria for this meta-analysis. Overexpression of DcR3 was significantly related to the risk of female reproductive cancers (OR=10.69, 95% CI: 6.33-18.05), TNM stage (OR=5.51, 95% CI: 2.83-10.71), differentiation (OR=4.16, 95% CI: 2.28-7.60), lymph node metastasis (OR=5.89, 95% CI: 3.16-10.9), age (OR=0.85, 95% CI: 0.51-1.44), and overall survival time (OR=1.84, 95% CI: 0.58-5.83). Subgroup analyses showed that overexpression of DcR3 in cervical, ovarian, and breast cancer all had similar relationships with these clinicopathological parameters. CONCLUSIONS Our meta-analysis suggests that overexpression of DcR3 may play vital roles in the tumorigenesis and deterioration of female reproductive cancers. However, the relationship between DcR3 expression and prognosis needs further investigation.

Quantum theory of terahertz conductivity of semiconductor nanostructures

NASA Astrophysics Data System (ADS)

Ostatnický, T.; Pushkarev, V.; Němec, H.; Kužel, P.

2018-02-01

Efficient and controlled charge carrier transport through nanoelements is currently a primordial question in the research of nanoelectronic materials and structures. We develop a quantum-mechanical theory of the conductivity spectra of confined charge carriers responding to an electric field from dc regime up to optical frequencies. The broken translation symmetry induces a broadband drift-diffusion current, which is not taken into account in the analysis based on Kubo formula and relaxation time approximation. We show that this current is required to ensure that the dc conductivity of isolated nanostructures correctly attains zero. It causes a significant reshaping of the conductivity spectra up to terahertz or multiterahertz spectral ranges, where the electron scattering rate is typically comparable to or larger than the probing frequency.

Reprint of “Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS”

NASA Astrophysics Data System (ADS)

Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

2013-01-01

The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

Performance analysis of a model-sized superconducting DC transmission system based VSC-HVDC transmission technologies using RTDS

NASA Astrophysics Data System (ADS)

Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Sung-Kyu; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun

2012-08-01

The combination of a high temperature superconducting DC power cable and a voltage source converter based HVDC (VSC-HVDC) creates a new option for transmitting power with multiple collection and distribution points for long distance and bulk power transmissions. It offers some greater advantages compared with HVAC or conventional HVDC transmission systems, and it is well suited for the grid integration of renewable energy sources in existing distribution or transmission systems. For this reason, a superconducting DC transmission system based HVDC transmission technologies is planned to be set up in the Jeju power system, Korea. Before applying this system to a real power system on Jeju Island, system analysis should be performed through a real time test. In this paper, a model-sized superconducting VSC-HVDC system, which consists of a small model-sized VSC-HVDC connected to a 2 m YBCO HTS DC model cable, is implemented. The authors have performed the real-time simulation method that incorporates the model-sized superconducting VSC-HVDC system into the simulated Jeju power system using Real Time Digital Simulator (RTDS). The performance analysis of the superconducting VSC-HVDC systems has been verified by the proposed test platform and the results were discussed in detail.

Modeling and control of fuel cell based distributed generation systems

NASA Astrophysics Data System (ADS)

Jung, Jin Woo

This dissertation presents circuit models and control algorithms of fuel cell based distributed generation systems (DGS) for two DGS topologies. In the first topology, each DGS unit utilizes a battery in parallel to the fuel cell in a standalone AC power plant and a grid-interconnection. In the second topology, a Z-source converter, which employs both the L and C passive components and shoot-through zero vectors instead of the conventional DC/DC boost power converter in order to step up the DC-link voltage, is adopted for a standalone AC power supply. In Topology 1, two applications are studied: a standalone power generation (Single DGS Unit and Two DGS Units) and a grid-interconnection. First, dynamic model of the fuel cell is given based on electrochemical process. Second, two full-bridge DC to DC converters are adopted and their controllers are designed: an unidirectional full-bridge DC to DC boost converter for the fuel cell and a bidirectional full-bridge DC to DC buck/boost converter for the battery. Third, for a three-phase DC to AC inverter without or with a Delta/Y transformer, a discrete-time state space circuit model is given and two discrete-time feedback controllers are designed: voltage controller in the outer loop and current controller in the inner loop. And last, for load sharing of two DGS units and power flow control of two DGS units or the DGS connected to the grid, real and reactive power controllers are proposed. Particularly, for the grid-connected DGS application, a synchronization issue between an islanding mode and a paralleling mode to the grid is investigated, and two case studies are performed. To demonstrate the proposed circuit models and control strategies, simulation test-beds using Matlab/Simulink are constructed for each configuration of the fuel cell based DGS with a three-phase AC 120 V (L-N)/60 Hz/50 kVA and various simulation results are presented. In Topology 2, this dissertation presents system modeling, modified space vector PWM implementation (MSVPWM) and design of a closed-loop controller of the Z-source converter which utilizes L and C components and shoot-through zero vectors for the standalone AC power generation. The fuel cell system is modeled by an electrical R-C circuit in order to include slow dynamics of the fuel cells and a voltage-current characteristic of a cell is also considered. A discrete-time state space model is derived to implement digital control and a space vector pulse-width modulation (SVPWM) technique is modified to realize the shoot-through zero vectors that boost the DC-link voltage. Also, three discrete-time feedback controllers are designed: a discrete-time optimal voltage controller, a discrete-time sliding mode current controller, and a discrete-time PI DC-link voltage controller. Furthermore, an asymptotic observer is used to reduce the number of sensors and enhance the reliability of the system. To demonstrate the analyzed circuit model and proposed control strategy, various simulation results using Matlab/Simulink are presented under both light/heavy loads and linear/nonlinear loads for a three-phase AC 208 V (L-L)/60 Hz/10 kVA.

Miniaturized two-stack Blumlein pulser with a variable repetition-rate for non-thermal irreversible-electroporation experiments

NASA Astrophysics Data System (ADS)

Min, Sun-Hong; Kwon, Ohjoon; Sattorov, Matlabjon; Baek, In-Keun; Kim, Seontae; Jeong, Jin-Young; Hong, Dongpyo; Park, Seunghyuk; Park, Gun-Sik

2017-01-01

Non-thermal irreversible electroporation (NTIRE) to avoid thermal damage to cells during intense DC ns pulsed electric fields (nsPEFs) is a recent modality for medical applications. This mechanism, related to bioelectrical dynamics of the cell, is linked to the effect of a DC electric field and a threshold effect with an electrically stimulated membrane for the charge distribution in the cell. To create the NTIRE condition, the pulse width of the nsPEF should be shorter than the charging time constant of the membrane related to the cell radius, membrane capacitance, cytoplasm resistivity, and medium resistivity. It is necessary to design and fabricate a very intense nanosecond DC electric field pulser that is capable of producing voltages up to the level of 100 kV/cm with an artificial pulse width (˜ns) with controllable repetition rates. Many devices to generate intense DC nsPEF using various pulse-forming line technologies have been introduced thus far. However, the previous Blumlein pulse-generating devices are clearly inefficient due to the energy loss between the input voltage and the output voltage. An improved two-stage stacked Blumlein pulse-forming line can overcome this limitation and decrease the energy loss from a DC power supply. A metal oxide silicon field-effect transistor switch with a fast rise and fall time would enable a high repetition rate (max. 100 kHz) and good endurance against very high voltages (DC ˜ 30 kV). The load is designed to match the sample for exposure to cell suspensions consisting of a 200 Ω resistor matched with a Blumlein circuit and two electrodes without the characteristic RC time effect of the circuit (capacitance =0.174 pF).

Fast-response free-running frequency-stabilized dc-to-dc converter employing a state plane-trajectory control law

NASA Technical Reports Server (NTRS)

Huffman, S. D.; Burns, W. W., III; Wilson, T. G.; Owen, H. A., Jr.

1976-01-01

Implementations of a state-plane-trajectory control law for energy storage dc-to-dc converters are presented. Performance characteristics of experimental voltage step-up converter systems employing these implementations are reported and compared to theoretical predictions.

Non-Arrhenius viscosity related to short-time ion dynamics in a fragile molten salt.

PubMed

Singh, Prabhakar; Banhatti, Radha D; Funke, Klaus

2005-03-21

The equation T x sigmaDC(T) = alpha x exp[--(E*/kappa(B)T)--gamma x exp(E*/kappa(B)T)] has been used to understand the non-Arrhenius behaviour of the DC conductivity in supercooled glass-forming melts. Here, alpha, gamma and E* are parameters, E* denoting the activation energy for an elementary displacive step. Unlike the empirical VTF relation, our equation provides a link between the long-time and the short-time ion dynamics as observed in broad-band conductivity spectra. Surprisingly, the same equation with the same value of E* but different gamma successfully describes the fluidity (inverse viscosity) of a fragile glass-forming melt. This opens up the possibility of relating non-Arrhenius viscosities to short-time properties, which is in agreement with recent experimental and computer-simulation results.

Synthesis and implementation of state-trajectory control law for dc-to-dc converters

NASA Technical Reports Server (NTRS)

Burns, W. W., III; Huffman, S. D.; Wilson, T. G.; Owen, H. A., Jr.

1977-01-01

Mathematical representations of a state-plane switching boundary employed in a state-trajectory control law for dc-to-dc converters are derived. Two approaches to implementing the control law are discussed; one approach employs a digital processor and the other uses analog computational circuits. Performance characteristics of experimental voltage step-up dc-to-dc converters operating under the control of each of these implementations are presented.

Automatic marker for photographic film

NASA Technical Reports Server (NTRS)

Gabbard, N. M.; Surrency, W. M.

1974-01-01

Commercially-produced wire-marking machine is modified to title or mark film rolls automatically. Machine is used with film drive mechanism which is powered with variable-speed, 28-volt dc motor. Up to 40 frames per minute can be marked, reducing time and cost of process.

Programme characteristics and everyday occupations in day centres and clubhouses in Sweden.

PubMed

Hultqvist, Jenny; Markström, Urban; Tjörnstrand, Carina; Eklund, Mona

2017-05-01

Meaningful everyday occupations are important for mental health and recovery and are provided by both community-based day centres (DCs) and clubhouses. It is unknown, however, if any of the two has more recovery-promoting features. This nine-month longitudinal study compared DC and clubhouses, concerning the users' perceptions of unit and programme characteristics, and aspects of everyday occupations in terms of engagement and satisfaction. Stability over time in these respects, as well as motivation for participation and relationships with occupational engagement and satisfaction, were explored. Participants from 10 DCs (n = 128) and 5 clubhouses (n = 57) completed self-report instruments. DC attendees rated lower levels on two organizational factors; choice and ability to influence decisions, and the unit's social network. Motivation showed to be an important factor for perceived occupational engagement, which did not differ between the two groups. DC attendees were more satisfied with their everyday occupations at baseline, but that factor increased more in the clubhouse group and there was no group difference at follow-up. The unit and programme characteristics and occupational engagement showed stability over time. Clubhouses seemed more advantageous and DC services may consider developing users' opportunities for choice and decision-making, and peer support.

Optically Isolated Control of the MOCHI LabJet High Power Pulsed Plasma Experiment

NASA Astrophysics Data System (ADS)

Carroll, Evan; Quinley, Morgan; von der Linden, Jens; You, Setthivoine

2014-10-01

The MOCHI LabJet experiment designed to investigate the dynamics of astrophysical jets at the University of Washington, requires high energy pulsed power supplies for plasma generation and sustainment. Two 600 μ F, 10 kV DC, pulse forming, power supplies have been specifically developed for this application. For safe and convenient user operation, the power supplies are controlled remotely with optical isolation. Three input voltage signals are required for relay actuation, adjusting bank charging voltage, and to fire the experiment: long duration DC signals, long duration user adjustable DC signals and fast trigger pulses with < μ s rise times. These voltage signals are generated from National Instruments timing cards via LabVIEW and are converted to optical signals by coupling photodiodes with custom electronic circuits. At the experiment, the optical signals are converted back to usable voltage signals using custom circuits. These custom circuits and experimental set-up are presented. This work is supported by US DOE Grant DE-SC0010340.

Correction of penile ventral curvature in patients with minor or no hypospadias: a single surgeon's experience of 43 cases.

PubMed

Seo, Shogo; Ochi, Takanori; Yazaki, Yuta; Murakami, Hiroshi; Okawada, Manabu; Doi, Takashi; Miyano, Go; Koga, Hiroyuki; Lane, Geoffrey J; Yamataka, Atsuyuki

2016-10-01

To report our experience of correcting penile ventral curvature associated with minor or no hypospadias. We reviewed 43 penile ventral curvature patients treated by a single surgeon from 1997 to 2015. Of these, 23 had minor hypospadias. Curvature was corrected using degloving, chordectomy, dorsal plication (DP), tunica albuginea incision (TAI), or a combination of these. Outcome was confirmed by induced artificial erection and post-operative appearance. Mean age at curvature correction was 3.2 ± 2.6 years. 17/43 had degloving and chordectomy (DC), 16/43 had DP after DC, and 10/43 had TAI after DC, because of ventral shortening and severe curvature caused by a short hypoplastic urethra. Other procedures required were primary meatoplasty (n = 4) and urethroplasty (UP; n = 1) at the time of curvature correction, and UP after correction of curvature (n = 11). Complications included recurrence of curvature after DP (n = 3/16; 18.8 %) and urethral stenosis after UP with tubed peritoneum (n = 1/10; 10 %). There were no recurrences of curvature in TAI cases. Parents reported penile cosmesis as good (n = 38; 88.4 %), acceptable (n = 4; 9.3 %), or poor (n = 1; 2.3 %). We recommend TAI followed by UP for correcting penile ventral curvature with short hypoplastic urethra. Tubed peritoneum is not recommended for UP.

Relationship of CD86 surface marker expression and cytotoxicity on dendritic cells exposed to chemical allergen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hulette, Ben C.; Ryan, Cindy A.; Gildea, Lucy A.

2005-12-01

Human peripheral blood-derived dendritic cells (DC) respond to a variety of chemical allergens by up-regulating expression of the co-stimulatory molecule CD86. It has been postulated that this measure might provide the basis for an in vitro alternative approach for the identification of skin sensitizing chemicals. We recently reported that DC, exposed in culture to the highest non-cytotoxic concentrations of various chemical allergens, displayed marginal up-regulation of membrane CD86 expression; the interpretation being that such changes were insufficiently sensitive for the purposes of hazard identification. For the work presented here, immature DC were derived from human monocytes and treated with themore » chemical allergens 2,4-dinitrobenzenesulfonic acid (DNBS), nickel sulfate (NiSO{sub 4}), p-phenylenediamine (PPD), Bandrowski's base (BB), hydroquinone (HQ) and propyl gallate (PG) for 48 h at concentrations which induced both no to slight to moderate cytotoxicity. For comparison, DC were treated with the irritants sodium dodecyl sulfate (SDS), benzoic acid (BA), and benzalkonium chloride (BZC) at concentrations resulting in comparable levels of cytotoxicity. CD86 expression, as measured by flow cytometry, was consistently up-regulated (ranging from 162 to 386% control) on DC treated with concentrations of chemical allergens that induced approximately 10-15% cytotoxicity. The irritants BA and BZC did not induce up-regulation of CD86 expression when tested at concentrations that induced similar levels of cytotoxicity. SDS, however, up-regulated CD86 expression to 125-138% of control in 2/4 preparations when tested at concentrations which induced similar toxicity. Our results confirm that chemical allergens up-regulate CD86 expression on blood-derived DC and illustrate further that up-regulation of CD86 surface marker expression is more robust when DC are treated with concentrations of chemical allergen that induce slight to moderate cytotoxicity.« less

2015 South Carolina PV Soft Cost and Workforce Development Part 2: Six Month Confirmation of Anticipated Job Growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fox, Elise B.; Edwards, Thomas B.

In 2015, a program was initiated to carefully track and monitor the growth of the solar industry in SC. Prior to then, little information was available on the costs associated with distributed photovoltaic (PV) installations in the Southeastern US. For this report, data were collected from businesses on the number of hires they had at the end of 2014 and compared with data for 2015 and June 2016. It was found that the percentage of installers within the state who serve the residential sector increased to 82% from 67%. During the same time period, the average size of initiated installationsmore » for residential, commercial, and utility scale installations all trended upwards. Where residential installations were typically 5 kW-DC in 2014, they were typically 10 kW-DC by late 2015 and in mid-2016. For commercial installations, the average size grew from 84 kW-DC in 2014 to between 136-236 kW-DC in 2015 and then 188-248 kWDC in mid-2016. An exception was seen in utility scale installations where a 2.3 MW-DC system was common in 2014, the size grew to be 5-15 MW-DC in late 2015. The average size dropped 3.1-4.4 MWDC in mid-June 2016, though individual averages up to 20 MW-DC were reported.« less

Multi Bus DC-DC Converter in Electric Hybrid Vehicles

NASA Astrophysics Data System (ADS)

Krithika, V.; Subramaniam, C.; Sridharan, R.; Geetha, A.

2018-04-01

This paper is cotncerned with the design, simulation and fabrication of the prototype of a Multi bus DC- DC converter operating from 42V DC and delivering 14V DC and 260V DC. As a result, three DC buses are interconnected through a single power electronic circuitry. Such a requirement is energized in the development of a hybrid electric automobile which uses the technology of fuel cell. This is implemented by using a Bidirectional DC-DC converter configuration which is ideally suitable for multiple outputs with mutual electrical isolation. For the sake of reduced size and cost of step-up transformer, selection of a high frequency switching cycle at 10 KHz was done.

Push-pull with recovery stage high-voltage DC converter for PV solar generator

NASA Astrophysics Data System (ADS)

Nguyen, The Vinh; Aillerie, Michel; Petit, Pierre; Pham, Hong Thang; Vo, Thành Vinh

2017-02-01

A lot of systems are basically developed on DC-DC or DC-AC converters including electronic switches such as MOS or bipolar transistors. The limits of efficiency are quickly reached when high output voltages and high input currents are needed. This work presents a new high-efficiency-high-step-up based on push-pull DC-DC converter integrating recovery stages dedicated to smart HVDC distributed architecture in PV solar energy production systems. Appropriate duty cycle ratio assumes that the recovery stage work with parallel charge and discharge to achieve high step-up voltage gain. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit and thus, low on-state resistance Rdson of the main switch can be adopted to reduce conduction losses. Thus, the efficiency of a basic DC-HVDC converter dedicated to renewable energy production can be further improved with such topology. A prototype converter is developed, and experimentally tested for validation.

Characterization of the duplicate L-SIGN and DC-SIGN genes in miiuy croaker and evolutionary analysis of L-SIGN in fishes.

PubMed

Shu, Chang; Wang, Shanchen; Xu, Tianjun

2015-05-01

Dendritic cell-specific ICAM-3-grabbing non-integrin (DC-SIGN/CD209) and liver/lymph node-specific ICAM-grabbing non-integrin (L-SIGN/CD299) which are homologues of DC-SIGN are important members in C-type lectin receptors family as key molecules to recognize and eliminate pathogens in the innate immune system. DC-SIGN and L-SIGN have become hot topics in recent studies which both served as cell adhesion and phagocytic pathogen recognition receptors in mammals. However, there have been almost no studies of DC-SIGN and L-SIGN structure and characters in fish, only DC-SIGN in the zebrafish had been studied. In our study, we identified and characterized the full-length miiuy croaker (Miichthys miiuy) DC-SIGN (mmDC-SIGN) and L-SIGN (mmL-SIGN) genes. The sequence analysis results showed that mmDC-SIGN and mmL-SIGN have the same domains with other vertebrates except primates, and share some conserved motifs in CRD among all the vertebrates which play a crucial role in interacting with Ca(2+) and for recognizing mannose-containing motifs. Gene synteny of DC-SIGN and L-SIGN were analyzed for the first time and gene synteny of L-SIGN was conserved among the five fishes. Interestingly, one gene next to L-SIGN from gene synteny had high similarity with L-SIGN gene that was described as L-SIGN-like in fish species. While only one L-SIGN gene existed in other vertebrates, two L-SIGN in fish may be in consequence of the fish-specific genome duplication to adapt the specific environment. The evolutionary analysis showed that the ancestral lineages of L-SIGN gene in fishes experienced purifying selection and the current lineages of L-SIGN gene in fishes underwent positive selection, indicating that the ancestral lineages and current lineages of L-SIGN gene in fishes underwent different evolutionary patterns. Both mmDC-SIGN and mmL-SIGN were expressed in all tested tissues and ubiquitously up-regulated in infected liver, spleen and kidney at different sampling time points, indicating that the mmDC-SIGN and mmL-SIGN participated in the immune response to defense against bacteria infection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Alkaloid decomposition by DC pin-hole discharge in water solution

NASA Astrophysics Data System (ADS)

Klimova, Edita J.; Krcma, Frantisek; Jonisova, Lenka

2016-08-01

DC diaphragm discharge generated in a batch reactor was used to decompose two selected model alkaloids, caffeine and quinine in concentrations ranging from 10 to 50 ppm or 5 to 15 ppm, respectively. UV-vis spectrometry was utilized in evaluation of H2O2 production during the process as well as degradation of caffeine. Fluorescence spectrometry was used for quantification of quinine. High rates of decomposition were reached in both cases in the anode part of the reactor. On the other hand, up to four times lower decomposition was observed in the cathode part. Total removal efficiency gained up to 300 mg/kWh for caffeine and 210 mg/kWh for quinine. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

Energy harvesting using TEG and PV cell for low power application

NASA Astrophysics Data System (ADS)

Tawil, Siti Nooraya Mohd; Zainal, Mohd Zulkarnain

2018-02-01

A thermoelectric generator (TEG) module and photovoltaic cell (PV) were utilized to harvest energy from temperature gradients of heat sources from ambient heat and light of sun. The output of TEG and PV were connected to a power management circuit consist of step-up dc-dc converter in order to increase the output voltage to supply a low power application such as wireless communication module and the photovoltaic cell for charging an energy storage element in order to switch on a fan for cooling system of the thermoelectric generator. A switch is used as a selector to choose the input of source either from photovoltaic cell or thermoelectric generator to switch on DC-DC step-up converter. In order to turn on the DC-DC step-up converter, the input must be greater than 3V. The energy harvesting was designed so that it can be used continuously and portable anywhere. Multiple sources used in this energy harvesting system is to ensure the system can work in whatever condition either in good weather or not good condition of weather. This energy harvesting system has the potential to be used in military operation and environment that require sustainability of energy resources.

The Fiscal Impact of the D.C. Voucher Program

ERIC Educational Resources Information Center

Aud, Susan L.; Michos, Leon

2006-01-01

In August 2004 the first ever federally funded school voucher program began in Washington, D.C. Eligible students could attend a private school of their choice in the District of Columbia. Each participant received up to $7,500 for school tuition, fees, and transportation. In addition, the D.C. Public School System (DCPS) and D.C. charter school…

Research on design feasibility of high-power light-weight dc-to-dc converters for space power applications

NASA Technical Reports Server (NTRS)

Wilson, T. G.

1981-01-01

Utilizing knowledge gained from past experience with experimental current-or-voltage step-up dc-to-dc converter power stages operating at output powers up to and in excess of 2 kW, a new experimental current-or-voltage step-up power stage using paralleled bipolar junction transistors (BJTs) as the controlled power switch, was constructed during the current reporting period. The major motivation behind the construction of this new experimental power stage was to improve the circuit layout so as to reduce the effects of stray circuit parasitic inductances resulting from excess circuit lead lengths and circuit loops, and to take advantage of the layout improvements which could be made when some recently-available power components, particularly power diodes and polypropylene filter capacitors, were incorporated into the design.

Hy-wire and fast electric field change measurements near an isolated thunderstorm, appendix C

NASA Technical Reports Server (NTRS)

Holzworth, R. H.; Levine, D. M.

1983-01-01

Electric field measurements near an isolated thunderstorm at 6.4 km distance are presented from both a tethered balloon experiment called Hy-wire and also from ground based fast and slow electric field change systems. Simultaneous measurements were made of the electric fields during several lightning flashes at the beginning of the storm which the data clearly indicate were cloud-to-ground flashes. In addition to providing a comparison between the Hy-wire technique for measuring electric fields and more traditional methods, these data are interesting because the lightning flashes occurred prior to changes in the dc electric field, although Hy-wire measured changes in the dc field of up to 750 V/m in the direction opposite to the fair weather field a short time later. Also, the dc electric field was observed to decay back to its preflash value after each flash. The data suggest that Hy-wire was at the field reversal distance from this storm and suggest the charge realignment was taking place in the cloud with a time constant on the order of 20 seconds.

An Integrated Programmable Wide-range PLL for Switching Synchronization in Isolated DC-DC Converters

NASA Astrophysics Data System (ADS)

Fard, Miad

In this thesis, two Phase-Locked-Loop (PLL) based synchronization schemes are introduced and applied to a bi-directional Dual-Active-Bridge (DAB) dc-dc converter with an input voltage up to 80 V switching in the range of 250 kHz to 1 MHz. The two schemes synchronize gating signals across an isolated boundary without the need for an isolator per transistor. The Power Transformer Sensing (PTS) method utilizes the DAB power transformer to indirectly sense switching on the secondary side of the boundary, while the Digital Isolator Sensing (DIS) method utilizes a miniature transformer for synchronization and communication at up to 100 MHz. The PLL is implemented on-chip, and is used to control an external DAB power-stage. This work will lead to lower cost, high-frequency isolated dc-dc converters needed for a wide variety of emerging low power applications where isolator cost is relatively high and there is a demand for the reduction of parts.

Wheels-up landing, Continental Airlines flight 1943, Douglas DC-9 N10556, Houston, Texas, February 19, 1996

DOT National Transportation Integrated Search

1997-02-11

Adopted Feb. 11, 1997. Notation 6804. This report explains the wheels-up landing of Continental Airlines flight 1943, N10556, a Douglas DC-9 at Houston Intercontinental Airport, Houston, Texas. The safety issues discussed in the report include checkl...

Reverse time-dependent effect of alphafetoprotein and disease control on survival of patients with Barcelona Clinic Liver Cancer stage C hepatocellular carcinoma.

PubMed

Ponziani, Francesca Romana; Spinelli, Irene; Rinninella, Emanuele; Cerrito, Lucia; Saviano, Antonio; Avolio, Alfonso Wolfango; Basso, Michele; Miele, Luca; Riccardi, Laura; Zocco, Maria Assunta; Annicchiarico, Brigida Eleonora; Garcovich, Matteo; Biolato, Marco; Marrone, Giuseppe; De Gaetano, Anna Maria; Iezzi, Roberto; Giuliante, Felice; Vecchio, Fabio Maria; Agnes, Salvatore; Addolorato, Giovanni; Siciliano, Massimo; Rapaccini, Gian Lodovico; Grieco, Antonio; Gasbarrini, Antonio; Pompili, Maurizio

2017-12-28

To characterize the survival of cirrhotic patients with Barcelona Clinic Liver Cancer (BCLC) stage C hepatocellular carcinoma (HCC) and to ascertain the factors predicting the achievement of disease control (DC). The cirrhotic patients with BCLC stage C HCC evaluated by the Hepatocatt multidisciplinary group were subjected to the investigation. Demographic, clinical and tumor features, along with the best tumor response and overall survival were recorded. One hundred and ten BCLC stage C patients were included in the analysis; the median overall survival was 13.4 mo (95%CI: 10.6-17.0). Only alphafetoprotein (AFP) serum level > 200 ng/mL and DC could independently predict survival but in a time dependent manner, the former was significantly associated with increased risk of mortality within the first 6 mo of follow-up (HR = 5.073, 95%CI: 2.159-11.916, P = 0.0002), whereas the latter showed a protective effect against death after one year (HR = 0.110, 95%CI: 0.038-0.314, P < 0.0001). Only patients showing microvascular invasion and/or extrahepatic spread recorded lower chances of achieving DC (OR = 0.263, 95%CI: 0.111-0.622, P = 0.002). The BCLC stage C HCC includes a wide heterogeneous group of cirrhotic patients suitable for potentially curative treatments. The reverse and time dependent effect of AFP serum level and DC on patients' survival confers them as useful predictive tools for treatment management and clinical decisions.

Stamp transferred suspended graphene mechanical resonators for radio frequency electrical readout.

PubMed

Song, Xuefeng; Oksanen, Mika; Sillanpää, Mika A; Craighead, H G; Parpia, J M; Hakonen, Pertti J

2012-01-11

We present a simple micromanipulation technique to transfer suspended graphene flakes onto any substrate and to assemble them with small localized gates into mechanical resonators. The mechanical motion of the graphene is detected using an electrical, radio frequency (RF) reflection readout scheme where the time-varying graphene capacitor reflects a RF carrier at f = 5-6 GHz producing modulation sidebands at f ± f(m). A mechanical resonance frequency up to f(m) = 178 MHz is demonstrated. We find both hardening/softening Duffing effects on different samples and obtain a critical amplitude of ~40 pm for the onset of nonlinearity in graphene mechanical resonators. Measurements of the quality factor of the mechanical resonance as a function of dc bias voltage V(dc) indicates that dissipation due to motion-induced displacement currents in graphene electrode is important at high frequencies and large V(dc). © 2011 American Chemical Society

Research and Construction of DC Energy Measurement Traceability Technology

NASA Astrophysics Data System (ADS)

Zhi, Wang; Maotao, Yang; Jing, Yang

2018-02-01

With the implementation of energy saving and emission reduction policies, DC energy metering has been widely used in many fields. In view of the lack of a DC energy measurementtraceability system, in combination with the process of downward measurement transfer in relation to the DC charger-based field calibration technology and DC energy meter and shunt calibration technologies, the paper proposed DC fast charging, high DC, small DC voltage output and measuring technologies, and built a time-based plan by converting high DC voltage into low voltage and high current into low current and then into low voltage, leaving DC energy traceable to national standards in terms of voltage, current and time and thus filling in the gap in DC energy measurement traceability.

Investigation of SIS Up-Converters for Use in Multi-pixel Receivers

NASA Astrophysics Data System (ADS)

Uzawa, Yoshinori; Kojima, Takafumi; Shan, Wenlei; Gonzalez, Alvaro; Kroug, Matthias

2018-02-01

We propose the use of SIS junctions as a frequency up-converter based on quasiparticle mixing in frequency division multiplexing circuits for multi-pixel heterodyne receivers. Our theoretical calculation showed that SIS junctions have the potential to achieve positive gain and low-noise characteristics in the frequency up-conversion process at local oscillator (LO) frequencies larger than the voltage scale of the dc nonlinearity of the SIS junction. We experimentally observed up-conversion gain in a mixer with four-series Nb-based SIS junctions at the LO frequency of 105 GHz for the first time.

Spreading Freedom and Saving Money. The Fiscal Impact of the D.C. Voucher Program

ERIC Educational Resources Information Center

Aud, Susan L.; Michos, Leon

2006-01-01

In August 2004 the first ever federally funded school voucher program began in Washington, D.C. Eligible students could attend a private school of their choice in the District of Columbia. Each participant received up to $7,500 for school tuition, fees, and transportation. In addition, the D.C. Public School System (DCPS) and D.C. charter school…

Analysis of expressed sequence tags from a NaHCO(3)-treated alkali-tolerant plant, Chloris virgata.

PubMed

Nishiuchi, Shunsaku; Fujihara, Kazumasa; Liu, Shenkui; Takano, Tetsuo

2010-04-01

Chloris virgata Swartz (C. virgata) is a gramineous wild plant that can survive in saline-alkali areas in northeast China. To examine the tolerance mechanisms of C. virgata, we constructed a cDNA library from whole plants of C. virgata that had been treated with 100 mM NaHCO(3) for 24 h and sequenced 3168 randomly selected clones. Most (2590) of the expressed sequence tags (ESTs) showed significant similarity to sequences in the NCBI database. Of the 2590 genes, 1893 were unique. Gene Ontology (GO) Slim annotations were obtained for 1081 ESTs by BLAST2GO and it was found that 75 genes of them were annotated with GO terms "response to stress", "response to abiotic stimulus", and "response to biotic stimulus", indicating these genes were likely to function in tolerance mechanism of C. virgata. In a separate experiment, 24 genes that are known from previous studies to be associated with abiotic stress tolerance were further examined by real-time RT-PCR to see how their expressions were affected by NaHCO(3) stress. NaHCO(3) treatment up-regulated the expressions of pathogenesis-related gene (DC998527), Win1 precursor gene (DC998617), catalase gene (DC999385), ribosome inactivating protein 1 (DC999555), Na(+)/H(+) antiporter gene (DC998043), and two-component regulator gene (DC998236). Copyright 2010 Elsevier Masson SAS. All rights reserved.

Scalp-recorded slow EEG responses generated in response to hemodynamic changes in the human brain.

PubMed

Vanhatalo, S; Tallgren, P; Becker, C; Holmes, M D; Miller, J W; Kaila, K; Voipio, J

2003-09-01

To study whether hemodynamic changes in human brain generate scalp-EEG responses. Direct current EEG (DC-EEG) was recorded from 12 subjects during 5 non-invasive manipulations that affect intracranial hemodynamics by different mechanisms: bilateral jugular vein compression (JVC), head-up tilt (HUT), head-down tilt (HDT), Valsalva maneuver (VM), and Mueller maneuver (MM). DC shifts were compared to changes in cerebral blood volume (CBV) measured by near-infrared spectroscopy (NIRS). DC shifts were observed during all manipulations with highest amplitudes (up to 250 microV) at the midline electrodes, and the most pronounced changes (up to 15 microV/cm) in the DC voltage gradient around vertex. In spite of inter-individual variation in both amplitude and polarity, the DC shifts were consistent and reproducible for each subject and they showed a clear temporal correlation with changes in CBV. Our results indicate that hemodynamic changes in human brain are associated with marked DC shifts that cannot be accounted for by intracortical neuronal or glial currents. Instead, the data are consistent with a non-neuronal generator mechanism that is associated with the blood-brain barrier. These findings have direct implications for mechanistic interpretation of slow EEG responses in various experimental paradigms.

Burner ignition system

DOEpatents

Carignan, Forest J.

1986-01-21

An electronic ignition system for a gas burner is battery operated. The battery voltage is applied through a DC-DC chopper to a step-up transformer to charge a capacitor which provides the ignition spark. The step-up transformer has a significant leakage reactance in order to limit current flow from the battery during initial charging of the capacitor. A tank circuit at the input of the transformer returns magnetizing current resulting from the leakage reactance to the primary in succeeding cycles. An SCR in the output circuit is gated through a voltage divider which senses current flow through a flame. Once the flame is sensed, further sparks are precluded. The same flame sensor enables a thermopile driven main valve actuating circuit. A safety valve in series with the main gas valve responds to a control pressure thermostatically applied through a diaphragm. The valve closes after a predetermined delay determined by a time delay orifice if the pilot gas is not ignited.

Models and methods for assessing the value of HVDC and MVDC technologies in modern power grids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makarov, Yuri V.; Elizondo, Marcelo A.; O'Brien, James G.

This report reflects the results of U.S. Department of Energy’s (DOE) Grid Modernization project 0074 “Models and methods for assessing the value of HVDC [high-voltage direct current] and MTDC [multi-terminal direct current] technologies in modern power grids.” The work was done by the Pacific Northwest National Laboratory (PNNL) and Oak Ridge National Laboratory (ORNL) in cooperation with Mid-Continent Independent System Operator (MISO) and Siemens. The main motivation of this study was to show the benefit of using direct current (DC) systems larger than those in existence today as they overlap with the alternating current (AC) systems. Proper use of theirmore » flexibility in terms of active/reactive power control and fast response can provide much-needed services to the grid at the same time as moving large blocks of energy to take advantage of cost diversity. Ultimately, the project’s success will enable decision-makers and investors to make well-informed decisions regarding this use of DC systems. This project showed the technical feasibility of HVDC macrogrid for frequency control and congestion relief in addition to bulk power transfers. Industry-established models for commonly used technologies were employed, along with high-fidelity models for recently developed HVDC converter technologies; like the modular multilevel converters (MMCs), a voltage source converters (VSC). Models for General Electric Positive Sequence Load Flow (GE PSLF) and Siemens Power System Simulator (PSS/E), widely used analysis programs, were for the first time adapted to include at the same time both Western Electricity Coordinating Council (WECC) and Eastern Interconnection (EI), the two largest North American interconnections. The high-fidelity models and their control were developed in detail for MMC system and extended to HVDC systems in point-to-point and in three-node multi-terminal configurations. Using a continental-level mixed AC-DC grid model, and using a HVDC macrogrid power flow and transient stability model, the results showed that the HVDC macrogrid relieved congestion and mitigated loop flows in AC networks, and provided up to 24% improvement in frequency responses. These are realistic studies, based on the 2025 heavy summer and EI multi-regional modeling working group (MMWG) 2026 summer peak cases. This work developed high-fidelity models and simulation algorithms to understand the dynamics of MMC. The developed models and simulation algorithms are up to 25 times faster than the existing algorithms. Models and control algorithms for high-fidelity models were designed and tested for point-to-point and multi-terminal configurations. The multi-terminal configuration was tested connecting simplified models of EI, WI, and Electric Reliability Council of Texas (ERCOT). The developed models showed up to 45% improvement in frequency response with the connection of all the three asynchronous interconnections in the United States using fast and advanced DC technologies like the multi-terminal MMC-DC system. Future work will look into developing high-fidelity models of other advanced DC technologies, combining high-fidelity models with the continental-level model, incorporating additional services. More scenarios involving large-scale HVDC and MTDC will be evaluated.« less

Betalactam antibiotics affect human dendritic cells maturation through MAPK/NF-kB systems. Role in allergic reactions to drugs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopez, Soledad; Department of Medical Biochemistry, Molecular Biology and Immunology, The University of Seville Medical School, Seville; Gomez, Enrique

The mechanisms leading to drug allergy in predisposed patients, especially those related to T-cell-mediated drug hypersensitivity, are not well understood. A key event in allergic reactions to drugs is the maturation process undergone by dendritic cells (DCs). Although amoxicillin (AX) has been reported to interact and maturate DCs from patients with AX-induced delayed-type hypersensitivity, the cell signaling pathways related to AX-mediated DC maturation have not been elucidated. We sought to determine the role of the MAPK and NF-κΒ pathways on AX-induced DC maturation and functional status. For that purpose, in monocyte-derived-DCs from AX-delayed allergic patients and tolerant subjects, we analyzedmore » the activation pattern of p38MAPK, JNK, and ERK signaling and the NF-κB, maturation markers as well as endocytosis and allostimulatory capacities driven by AX-stimulated-DCs. Our data reveal that AX induces an increase in the phosphorylation levels of the three MAPKsand activated NF-κB in DCs from allergic patients. Moreover, the inhibition of these pathways prevents the up-regulation of surface molecules induced by AX. Additionally, we observed that the allostimulatory capacity and the endocytosis down-regulation in AX-stimulated-DCs from allergic patients depend on JNK and NF-κB activities. Taken together, our data shed light for the first time on the main signaling pathways involved in DC maturation from AX-delayed allergic patient. - Highlights: • The cell signaling pathways related to drug-mediated DC maturation were tested. • Amoxicillin induces activation of MAPK and NF-κB in DCs from allergic patients. • The inhibition of these pathways prevents the up-regulation of DC surface molecules. • Their allostimulatory and endocytosis capacities depend on JNK and NF-κB activities. • The low involvement of p38-MAPK could be the cause of an incomplete DC maturation.« less

Acute and sub-acute oral toxicity of Dracaena cinnabari resin methanol extract in rats.

PubMed

Al-Afifi, Nashwan Abdullah; Alabsi, Aied Mohammed; Bakri, Marina Mohd; Ramanathan, Anand

2018-02-05

Dracaena cinnabari (DC) is a perennial tree that located on the Southern coast of Yemen native to the Socotra Island. This tree produces a deep red resin known as the Dragon's blood, the Twobrother's Blood or Damm Alakhwain. The current study performed to evaluate the safety of the DC resin methanol extract after a single or 28 consecutive daily oral administrations. In assessing the safety of DC resin methanol extract, acute and sub-acute oral toxicity tests performed following OECD guidelines 423 and 407, respectively, with slight modifications. In acute oral toxicity test, DC resin methanol extract administered to female Sprague Dawley rats by oral gavage at a single dose of 300 and 2000 mg/kg body weight. Rats observed for toxic signs for 14 days. In sub-acute oral toxicity test, DC resin methanol extract administered to the rats by oral gavage at 500, 1000, and 1500 mg/kg body weight daily up to 28 days to male and female Spradgue Dawley rats. The control and high dose in satellite groups were also maintained and handled as the previous groups to determine the late onset toxicity of DC resin methanol extract. At the end of each test, hematological and biochemical analysis of the collected blood were performed as well as gross and microscopic pathology. In acute oral toxicity, no treatment-related death or toxic signs were observed. It revealed that the DC resin methanol extract could be well tolerated up to the dose 2000 mg/kg body weight and could be classified as Category 5. The sub-acute test observations indicated that there are no treatment-related changes up to the high dose level compared to the control. Food consumption, body weight, organ weight, hematological parameters, biochemical parameters and histopathological examination (liver, kidney, heart, spleen and lung) revealed no abnormalities. Water intake was significantly higher in the DC resin methanol extract treated groups compared to the control. This study demonstrates tolerability of DC resin methanol extract administered daily for 28 days up to 1500 mg/kg dose.

Temporal development and chemical efficiency of positive streamers in a large scale wire-plate reactor as a function of voltage waveform parameters

NASA Astrophysics Data System (ADS)

Winands, G. J. J.; Liu, Z.; Pemen, A. J. M.; van Heesch, E. J. M.; Yan, K.; van Veldhuizen, E. M.

2006-07-01

In this paper a large-scale pulsed corona system is described in which pulse parameters such as pulse rise-time, peak voltage, pulse width and energy per pulse can be varied. The chemical efficiency of the system is determined by measuring ozone production. The temporal and spatial development of the discharge streamers is recorded using an ICCD camera with a shortest exposure time of 5 ns. The camera can be triggered at any moment starting from the time the voltage pulse arrives on the reactor, with an accuracy of less than 1 ns. Measurements were performed on an industrial size wire-plate reactor. The influence of pulse parameters like pulse voltage, DC bias voltage, rise-time and pulse repetition rate on plasma generation was monitored. It was observed that for higher peak voltages, an increase could be seen in the primary streamer velocity, the growth of the primary streamer diameter, the light intensity and the number of streamers per unit length of corona wire. No significant separate influence of DC bias voltage level was observed as long as the total reactor voltage (pulse + DC bias) remained constant and the DC bias voltage remained below the DC corona onset. For those situations in which the plasma appearance changed (e.g. different streamer velocity, diameter, intensity), a change in ozone production was also observed. The best chemical yields were obtained for low voltage (55 kV), low energetic pulses (0.4 J/pulse): 60 g (kWh)-1. For high voltage (86 kV), high energetic pulses (2.3 J/pulse) the yield decreased to approximately 45 g (kWh)-1, still a high value for ozone production in ambient air (RH 42%). The pulse repetition rate has no influence on plasma generation and on chemical efficiency up to 400 pulses per second.

Tools for Physiology Labs: Inexpensive Equipment for Physiological Stimulation

PubMed Central

Land, Bruce R.; Johnson, Bruce R.; Wyttenbach, Robert A.; Hoy, Ronald R.

2004-01-01

We describe the design of inexpensive equipment and software for physiological stimulation in the neurobiology teaching laboratory. The core component is a stimulus isolation unit (SIU) that uses DC-DC converters, rather than expensive high-voltage batteries, to generate isolated power at high voltage. The SIU has no offset when inactive and produces pulses up to 100 V with moderately fast (50 μs) rise times. We also describe two methods of stimulus timing control. The first is a simplified conventional, stand-alone analog pulse generator. The second uses a digital microcontroller interfaced with a personal computer. The SIU has performed well and withstood intensive use in our undergraduate physiology laboratory. This project is part of our ongoing effort to make reliable low-cost physiology equipment available for both student teaching and faculty research laboratories. PMID:23493817

Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

NASA Astrophysics Data System (ADS)

Lee, F. C.; Mahmoud, M. F.; Yu, Y.

1980-04-01

The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1

NASA Technical Reports Server (NTRS)

Lee, F. C.; Mahmoud, M. F.; Yu, Y.

1980-01-01

The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.

DC to DC Converter Testing for Space Applications: Use of EMI Filters and Thermal Range of Operation

NASA Technical Reports Server (NTRS)

Leon, Rosa

2008-01-01

Several tests were performed on Interpoint and International Rectifier (IR) direct current (DC) to DC converters to evaluate potential performance and reliability issues in space use of DC to DC converters and to determine if the use of electromagnetic interference (EMI) filters mitigates concerns observed during previous tests. Test findings reported here include those done up until September - October 2008. Tests performed include efficiency, regulation, cross-regulation, power consumption with inhibit on, load transient response, synchronization, and turn-on tests. Some of the test results presented here span the thermal range -55 C to 125 C. Lower range was extended to -120 C in some tested converters. Determination of failure root cause in DC/DC converters that failed at thermal extremes is also included.

77 FR 22787 - HIT Policy Committee Advisory Meeting; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-17

... consistent with the Federal Health IT Strategic Plan and that includes recommendations on the areas in which... will be held on May 2, 2012, from 9:30 a.m. to 3 p.m./Eastern Time. Location: Washington Marriott, Location: Holiday Inn Capitol, 550 C Street SW., Washington, DC 20024. For up-to-date information, go to...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calabrese, G.; Capineri, L., E-mail: lorenzo.capineri@unifi.it; Granato, M.

This paper describes the design of a system for the characterization of magnetic hysteresis behavior in soft ferrite magnetic cores. The proposed setup can test magnetic materials exciting them with controlled arbitrary magnetic field waveforms, including the capability of providing a DC bias, in a frequency bandwidth up to 500 kHz, with voltages up to 32 V peak-to-peak, and currents up to 10 A peak-to-peak. In order to have an accurate control of the magnetic field waveform, the system is based on a voltage controlled current source. The electronic design is described focusing on closed loop feedback stabilization and passivemore » components choice. The system has real-time hysteretic loop acquisition and visualization. The comparisons between measured hysteresis loops of sample magnetic materials and datasheet available ones are shown. Results showing frequency and thermal behavior of the hysteresis of a test sample prove the system capabilities. Moreover, the B-H loops obtained with a multiple waveforms excitation signal, including DC bias, are reported. The proposal is a low-cost and replicable solution for hysteresis characterization of magnetic materials used in power electronics.« less

Human perception of electric fields and ion currents associated with high-voltage DC transmission lines.

PubMed

Blondin, J P; Nguyen, D H; Sbeghen, J; Goulet, D; Cardinal, C; Maruvada, P S; Plante, M; Bailey, W H

1996-01-01

The objective of this study was to assess the ability of humans to detect the presence of DC electric field and ion currents. An exposure chamber simulating conditions present in the vicinity of high-voltage DC (HVDC) lines was designed and built for this purpose. In these experiments, the facility was used to expose observers to DC electric fields up to 50 kV/m and ion current densities up to 120 nA/m2. Forty-eight volunteers (25 women and 23 men) between the ages of 18 and 57 years served as observers. Perception of DC fields was examined by using two psychophysical methods: an adaptive staircase procedure and a rating method derived from signal-detection theory. Subjects completed three different series of observations by using each of these methods; one was conducted without ion currents, and the other two involved various combinations of electric fields and ion currents. Overall, subjects were significantly more likely to detect DC fields as the intensity increased. Observers were able to detect the presence of DC fields alone, but only at high intensities; the average threshold was 45 kV/m. Except in the most sensitive individuals, ion current densities up to 60 nA/m2 did not significantly facilitate the detection of DC fields. However, higher ion current densities were associated with a substantial lowering of sensory thresholds in a large majority of observers. Data analysis also revealed large variations in perceptual thresholds among observers. Normative data indicating DC field and ion current intensities that can be detected by 50% of all observers are provided. In addition, for the most sensitive observers, several other detection proportions were derived from the distribution of individual detection capabilities. These data can form the basis for environmental guidelines relating to the design of HVDC lines.

Emulating DC constant power load: a robust sliding mode control approach

NASA Astrophysics Data System (ADS)

Singh, Suresh; Fulwani, Deepak; Kumar, Vinod

2017-09-01

This article presents emulation of a programmable power electronic, constant power load (CPL) using a dc/dc step-up (boost) converter. The converter is controlled by a robust sliding mode controller (SMC). A novel switching surface is proposed to ensure a required power sunk by the converter. The proposed dc CPL is simple in design, has fast dynamic response and high accuracy, and offers an inexpensive alternative to study converters for cascaded dc distribution power system applications. Furthermore, the proposed CPL is sufficiently robust against the input voltage variations. A laboratory prototype of the proposed dc CPL has been developed and validated with SMC realised through OPAL-RT platform. The capability of the proposed dc CPL is confirmed via experimentations in varied scenarios.

Practical Design Guidelines of qZSI Based Step-Up DC/DC Converter

NASA Astrophysics Data System (ADS)

Zakis, Janis; Vinnikov, Dmitri; Roasto, Indrek; Jalakas, Tanel

2010-01-01

This paper presents some design guidelines for a new voltage fed step-up DC/DC isolated converter. The most significant advantage of proposed converter is voltage buck-boost operation on single stage. The most promising application for proposed converter is in the field of distributed power generation e.g. fuel cells or photovoltaic. The most sensitive issues - such as power losses caused by high currents in the input side of converter and high transient overvoltages across the inverter bridge caused by stray inductances were discussed and solved. The proposals and recommendations to overcome these issues are given in the paper. The Selection and design guidelines of converter elements are proposed and explained. The prototype of proposed converter was built and experimentally tested. Some results are presented and evaluated.

Reappraisal of the clinical implications of adenosine triphosphate in terms of the prediction of reconnection sites in cases with electrical isolation of the pulmonary veins.

PubMed

Okishige, Kaoru; Aoyagi, Hideshi; Ihara, Kensuke; Iwai, Shinsuke; Nakamura, Tomofumi; Yamashita, Mitsumi; Katoh, Nobutaka; Hasegawa, Tomoaki; Kawaguchi, Naohiko; Keida, Takehiko; Sasano, Tetsuo; Hirao, Kenzo

2015-11-01

Dormant conduction (DC) induced by intravenous adenosine triphosphate (ATP) after pulmonary vein (PV) isolation (PVI) could predict subsequent PV reconnection (RC) sites. This study aimed to investigate the relationship between the DC and RC sites during the long-term follow-up. Ninety-one consecutive patients (62 males; mean age, 62 ± 11 years) with symptomatic persistent (n = 18) or paroxysmal (n = 73) atrial fibrillation (AF) who underwent PVI were included in this study. After a successful PVI, we administered ATP to reveal the DC sites. In total, DC sites were observed in 46 (51%) patients, and all were left un-ablated after marking or tagging all of them using fluoroscopic images and a three-dimensional (3D) mapping system. After the follow-up period (14.8 ± 3.6 months), AF recurred in 29 (32%) patients, all of whom had a DC in the initial ablation session, and underwent redo sessions. We divided the DC sites into three groups; in group A, the RC sites differed from the DC sites, in group B, the RC sites were identical to the DC sites, and in group C, the RC sites involved both DC and other sites. As a result, 20 (69%), 3 (11.5%), and 6 (19.5%) patients belonged to groups A, B, and C, respectively. Statistical analyses comparing the agreement between DC and the RC sites yielded a weak relationship. DC sites implying RC sites had a weak agreement, and other options to predict RC sites will be required to improve the clinical benefit of CA of AF.

Reverse time-dependent effect of alphafetoprotein and disease control on survival of patients with Barcelona Clinic Liver Cancer stage C hepatocellular carcinoma

PubMed Central

Ponziani, Francesca Romana; Spinelli, Irene; Rinninella, Emanuele; Cerrito, Lucia; Saviano, Antonio; Avolio, Alfonso Wolfango; Basso, Michele; Miele, Luca; Riccardi, Laura; Zocco, Maria Assunta; Annicchiarico, Brigida Eleonora; Garcovich, Matteo; Biolato, Marco; Marrone, Giuseppe; De Gaetano, Anna Maria; Iezzi, Roberto; Giuliante, Felice; Vecchio, Fabio Maria; Agnes, Salvatore; Addolorato, Giovanni; Siciliano, Massimo; Rapaccini, Gian Lodovico; Grieco, Antonio; Gasbarrini, Antonio; Pompili, Maurizio

2017-01-01

AIM To characterize the survival of cirrhotic patients with Barcelona Clinic Liver Cancer (BCLC) stage C hepatocellular carcinoma (HCC) and to ascertain the factors predicting the achievement of disease control (DC). METHODS The cirrhotic patients with BCLC stage C HCC evaluated by the Hepatocatt multidisciplinary group were subjected to the investigation. Demographic, clinical and tumor features, along with the best tumor response and overall survival were recorded. RESULTS One hundred and ten BCLC stage C patients were included in the analysis; the median overall survival was 13.4 mo (95%CI: 10.6-17.0). Only alphafetoprotein (AFP) serum level > 200 ng/mL and DC could independently predict survival but in a time dependent manner, the former was significantly associated with increased risk of mortality within the first 6 mo of follow-up (HR = 5.073, 95%CI: 2.159-11.916, P = 0.0002), whereas the latter showed a protective effect against death after one year (HR = 0.110, 95%CI: 0.038-0.314, P < 0.0001). Only patients showing microvascular invasion and/or extrahepatic spread recorded lower chances of achieving DC (OR = 0.263, 95%CI: 0.111-0.622, P = 0.002). CONCLUSION The BCLC stage C HCC includes a wide heterogeneous group of cirrhotic patients suitable for potentially curative treatments. The reverse and time dependent effect of AFP serum level and DC on patients’ survival confers them as useful predictive tools for treatment management and clinical decisions. PMID:29359015

Overproduction of S-adenosylmethionine decarboxylase in ethylglyoxal-bis(guanylhydrazone)-resistant mouse FM3A cells.

PubMed

Suzuki, T; Sadakata, Y; Kashiwagi, K; Hoshino, K; Kakinuma, Y; Shirahata, A; Igarashi, K

1993-07-15

A variant cell line, termed SAM-1, which overproduced S-adenosylmethionine decarboxylase (AdoMetDC), was isolated by treatment of mouse FM3A cells with N-methyl-N'-nitro-N-nitrosoguanidine and subsequent incubation with ethylglyoxal bis(guanylhydrazone), an inhibitor of the enzyme. The cells were resistant to ethylglyoxal bis(guanylhydrazone), and showed AdoMetDC activity approximately five-times higher than control cells. The rate of AdoMetDC synthesis and the amount of AdoMetDC existing in SAM-1 cells were about five-times those in control cells. The amount of AdoMetDC mRNA existing in SAM-1 cells was five-times more than that in control cells. The amount of 5'-([(Z)-4-amino-2-butenyl]methylamino)-5'-deoxyadenosine, an irreversible inhibitor of AdoMetDC, necessary to inhibit cell growth was also five-times more in SAM-1 cells than in control cells. However, the following were the same in both SAM-1 and control cells; the amount of genomic DNA for AdoMetDC, the size and nucleotide sequence of 5' untranslated region of AdoMetDC mRNA, the deduced amino acid sequence (334 residues) from the nucleotide sequence of AdoMetDC cDNA and the degradation rate (t1/2 = about 4 h) of AdoMetDC. In addition, AdoMetDC mRNA in control cells was slightly more stable than that in SAM-1 cells. The results indicate that the overproduction of AdoMetDC in SAM-1 cells was caused by the increase of AdoMetDC mRNA. The variant cell line is convenient for studying the regulation of AdoMetDC and the physiological function of polyamines.

Experimental demonstration of a real-time high-throughput digital DC blocker for compensating ADC imperfections in optical fast-OFDM receivers.

PubMed

Zhang, Lu; Ouyang, Xing; Shao, Xiaopeng; Zhao, Jian

2016-06-27

Performance degradation induced by the DC components at the output of real-time analogue-to-digital converter (ADC) is experimentally investigated for optical fast-OFDM receiver. To compensate this degradation, register transfer level (RTL) circuits for real-time digital DC blocker with 20GS/s throughput are proposed and implemented in field programmable gate array (FPGA). The performance of the proposed real-time digital DC blocker is experimentally investigated in a 15Gb/s optical fast-OFDM system with intensity modulation and direct detection over 40 km standard single-mode fibre. The results show that the fixed-point DC blocker has negligible performance penalty compared to the offline floating point one, and can overcome the error floor of the fast OFDM receiver caused by the DC components from the real-time ADC output.

Research on spacecraft electrical power conversion

NASA Technical Reports Server (NTRS)

Wilson, T. G.

1974-01-01

The steady state characteristics and starting behavior of some widely used self-oscillating magnetically coupled square wave inverters were studied and the development of LC-tuned square wave inverters is reported. An analysis on high amplitude voltage spikes which occur in dc-to-square-wave parallel converters shows the importance of various circuit parameters for inverter design and for the suppression of spikes. A computerized simulation of an inductor energy storage dc-to-dc converter with closed loop regulators and of a preregulating current step-up converter are detailed. Work continued on the computer aided design of two-winding energy storage dc-to-dc converters.

Design and dSpace interfacing of current fed high gain dc to dc boost converter for low voltage applications

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Debraj; Das, Subhrajit; Arunkumar, G.; Elangovan, D.; Ragunath, G.

2017-11-01

In this paper a current fed interleaved DC - DC boost converter which has an isolated topology and used for high voltage step up is proposed. A basic DC to DC boost converter converts uncontrolled DC voltage into controlled DC voltage of higher magnitude. Whereas this topology has the advantages of lower input current ripple, lesser output voltage, lesser stress on switches, faster transient response, improved reliability and much lesser electromagnetic emission over the conventional DC to DC boost converter. Most important benefit of this interleaved DC to DC boost converter is much higher efficiency. The input current is divided into two paths, substantially ohmic loss (I2R) and inductor ac loss gets reduced and finally the system achieves much higher efficiency. With recent mandates on energy saving interleaved DC to DC boost converter may be used as a very powerful tool to maintain good power density keeping the input current manageable. Higher efficiency also allows higher switching frequency and as a result the topology becomes more compact and cost friendly. The proposed topology boosts 48v DC to 200 V DC. Switching frequency is 100 kHz and PSIM 9.1 Platform has been used for the simulation.

Reliability enhancement of Ohmic RF MEMS switches

NASA Astrophysics Data System (ADS)

Kurth, Steffen; Leidich, Stefan; Bertz, Andreas; Nowack, Markus; Frömel, Jörg; Kaufmann, Christian; Faust, Wolfgang; Gessner, Thomas; Akiba, Akira; Ikeda, Koichi

2011-02-01

This contribution deals with capacitively actuated Ohmic switches in series single pole single throw (SPST) configuration for DC up to 4 GHz signal frequency (<0.5 dB insertion loss, 35 dB isolation) and in shunt switch SPST configuration for a frequency range from DC up to 80 GHz (<1.2 dB insertion loss, 18 dB isolation at 60 GHz). A novel high aspect ratio MEMS fabrication sequence in combination with wafer level packaging is applied for fabrication of the samples and allows for a relatively large actuation electrode area, and for high actuation force resulting in fast onresponse time of 10 μs and off-response time of 6 μs at less than 5 V actuation voltage. Large actuation electrode area and a particular design feature for electrode over travel and dynamic contact separation lead to high contact force in the closed state and to high force for contact separation to overcome sticking. The switch contacts, which are consisting of noble metal, are made in one of the latest process steps. This minimizes contamination of the contact surfaces by fabrication sequence residuals. A life time of 1 Billion switch cycles has been achieved. This paper covers design for reliability issues and reliability test methods using accelerated life time test. Different test methods are combined to examine electric and mechanical motion parameters as well as RF performance.

Airborne remote sensing of ultraviolet-absorbing aerosols during the NASA ATom, SEAC4RS and DC3 campaigns

NASA Astrophysics Data System (ADS)

Hall, S. R.; Ullmann, K.; Commane, R.; Crounse, J. D.; Daube, B. C.; Diskin, G. S.; Dollner, M.; Froyd, K. D.; Katich, J. M.; Kim, M. J.; Madronich, S.; Murphy, D. M.; Podolske, J. R.; Schwarz, J. P.; Teng, A.; Weber, R. J.; Weinzierl, B.; Wennberg, P. O.; Sachse, G.; Wofsy, S.

2017-12-01

Spectrally resolved up and down-welling actinic flux was measured from the NASA DC-8 aircraft by the Charged-coupled device Actinic Flux Spectroradiometers (CAFS) during recent campaigns including ATom, DC3 and SEAC4RS. The primary purpose is retrieval of 40 photolysis frequencies to complement the in situ chemistry. However, the spectra also provide the opportunity to examine absorption trends in the UV where few other measurements exist. In particular, absorption by brown (BrC) and black (BC) carbon aerosols result in characteristic UV signatures. A new technique exploits the spectral changes to detect the presence of these aerosols for qualitative, real-time, remote sensing of biomass burning (BB). The data may prove useful for examination of the evolution of BrC, including chemical processing and hygroscopic growth. The induced UV changes also feed back to the photolysis frequencies affecting the chemistry. Further work will determine the robustness of the technique and if quantitative spectral absorption retrievals are possible.

Up-and-down chopper circuit

DOEpatents

Goffeau, Jacques R.

1979-01-01

An improved Up-and-Down Chopper Circuit is provided which is useful for voltage regulation in a bi-directional DC power system. In the down mode, power is switched from a DC power source to a lower voltage energy storing load while in the up mode stored energy in the load is transferred to the higher voltage source. The system uses Darlington transistor switches in a conventional connection. The improvement relates to circuit additions to eliminate the effects of inter-electrode capacitance inherent with this Darlington transistor switching arrangement.

Silicon Carbide Diodes Characterization at High Temperature and Comparison With Silicon Devices

NASA Technical Reports Server (NTRS)

Lebron-Velilla, Ramon C.; Schwarze, Gene E.; Gardner, Brent G.; Adams, Jerry D., Jr.

2004-01-01

Commercially available silicon carbide (SiC) Schottky diodes from different manufacturers rated at 200, 300, 600, and 1200 V, were electrically tested and characterized as a function of temperature up to 300 C. Electrical tests included both steady state and dynamic tests. Steady state tests produced forward and reverse I-V characteristic curves. Transient tests evaluated the switching performance of the diodes in either a hard-switched DC to DC buck converter or a half-bridge boost converter. For evaluation and comparison purposes, the same tests were performed with current state-of-the-art ultra fast silicon (Si) pn-junction diodes of similar ratings and also a Si Schottky diode. The comparisons made were forward voltage drop at rated current, reverse current at rated voltage, and turn-off peak reverse recovery current and reverse recovery time. In addition, efficiency measurements were taken for the buck DC to DC converter using both the SiC Schottky diodes and the Si pn-junction diodes at different temperatures and frequencies. The test results showed that at high temperature, the forward voltage drop for SiC Schottky diodes is higher than the forward drop of the ultra fast Si pn-junction diodes. As the temperature increased, the forward voltage drop of the SiC Schottky increased while for the ultra fast Si pn-junction diodes, the forward voltage drop decreased as temperature increased. For the elevated temperature steady state reverse voltage tests, the SiC Schottky diodes showed low leakage current at their rated voltage. Likewise, for the transient tests, the SiC Schottky diodes displayed low reverse recovery currents over the range of temperatures tested. Conversely, the Si pn-junction diodes showed increasing peak reverse current values and reverse recovery times with increasing temperature. Efficiency measurements in the DC to DC buck converter showed the advantage of the SiC Schottky diodes over the ultra fast Si pn-junction diodes, especially at the higher temperatures and higher frequencies.

Safety and activity of PD-1 blockade-activated DC-CIK cells in patients with advanced solid tumors.

PubMed

Chen, Chang-Long; Pan, Qiu-Zhong; Weng, De-Sheng; Xie, Chuan-Miao; Zhao, Jing-Jing; Chen, Min-Shan; Peng, Rui-Qing; Li, Dan-Dan; Wang, Ying; Tang, Yan; Wang, Qi-Jing; Zhang, Zhi-Ling; Zhang, Xiao-Fei; Jiang, Li-Juan; Zhou, Zi-Qi; Zhu, Qian; He, Jia; Liu, Yuan; Zhou, Fang-Jian; Xia, Jian-Chuan

2018-01-01

Cytokine-induced killer (CIK) cells that are stimulated using mature dendritic cells (DCs), referred to as (DC-CIK cells) exhibit superior anti-tumor potency. Anti-programmed death-1 (PD-1) antibodies reinvigorate T cell-mediated antitumor immunity. This phase I study aimed to assess the safety and clinical activity of immunotherapy with PD-1 blockade (pembrolizumab)-activated autologous DC-CIK cells in patients with advanced solid tumors. Patients with selected types of advanced solid tumors received a single intravenous infusion of activated autologous DC-CIK cells weekly for the first month and every 2 weeks thereafter. The primary end points were safety and adverse event (AE) profiles. Antitumor responses, overall survival (OS), progression-free survival (PFS) and cytolytic activity were secondary end points. Treatment-related AEs occurred in 20/31 patients. Grade 3 or 4 toxicities, including fever and chills, were observed in two patients. All treatment-related AEs were reversible or controllable. The cytotoxicity of DC-CIK cells induced up-regulation of PD-L1 expression on autologous tumor cells. When activated using pembrolizumab ex vivo , DC-CIK cells exerted superior antitumor properties and elevated IFN-γ secretion. Objective responses (complete or partial responses) were observed in 7 of the 31patients.These responses were durable, with 6 of 7 responses lasting more than 5 months. The overall disease control rate in the patients was 64.5%. At the time of this report, the median OS and PFS were 270 and 162 days, respectively. In conclusions, treatment with pembrolizumab-activated autologous DC-CIK cells was safe and exerted encouraging antitumor activity in advanced solid tumors. A larger phase II trial is warranted.

Interaction between geriatric nutritional risk index and decoy receptor 3 predicts mortality in chronic hemodialysis patients.

PubMed

Tsai, Ming-Tsun; Hu, Fen-Hsiang; Lien, Tse-Jen; Chen, Ping-Jen; Huang, Tung-Po; Tarng, Der-Cherng

2014-01-01

Protein-energy wasting (PEW) is common and associated with poor outcome in hemodialysis patients. In hemodialysis patients, geriatric nutritional risk index (GNRI) and decoy receptor 3 (DcR3) have been shown as the nutritional and inflammatory markers, respectively. The present study aimed to assess the predictive ability of GNRI and DcR3 for PEW status and long-term outcomes in chronic hemodialysis patients. A prospective cohort of 318 hemodialysis patients was conducted with a median follow-up of 54 months. Malnutrition-inflammation score (MIS) was used as the reference standard for the presence of PEW. Endpoints were cardiovascular and all-cause mortality. Baseline GNRI had a strong negative correlation with DcR3 and MIS score. For patients with age < or ≥60, high DcR3 and low GNRI were independent predictors for the presence of PEW at baseline. At the end of the study, 81 patients died (27 cardiovascular deaths). The adjusted hazard ratios (95% confidence intervals) of low GNRI and high DcR3 were 1.93 (1.1-4.8) and 2.53 (1.2-5.5) for cardiovascular mortality and 1.85 (1.1-3.2) and 2.37 (1.5-3.7) for all-cause mortality, respectively. While integrated into a model of conventional risk factors, GNRI together with DcR3 further significantly improved the predictability for overall mortality (c statistic, 0.823). Low GNRI and high DcR3 were the alternatives for identifying hemodialysis patients at risk of PEW and overall mortality. Further studies are needed to verify whether timely recognition of hemodialysis patients with a high malnutrition-inflammation risk could reduce their mortality by appropriate interventional strategies.

Power supply standardization and optimization study

NASA Technical Reports Server (NTRS)

Ware, C. L.; Ragusa, E. V.

1972-01-01

A comprehensive design study of a power supply for use in the space shuttle and other space flight applications is presented. The design specifications are established for a power supply capable of supplying over 90 percent of the anticipated voltage requirements for future spacecraft avionics systems. Analyses and tradeoff studies were performed on several alternative design approaches to assure that the selected design would provide near optimum performance of the planned applications. The selected design uses a dc-to-dc converter incorporating regenerative current feedback with a time-ratio controlled duty cycle to achieve high efficiency over a wide variation in input voltage and output loads. The packaging concept uses an expandable mainframe capable of accommodating up to six inverter/regulator modules with one common input filter module.

Human Macrophages and Dendritic Cells Can Equally Present MART-1 Antigen to CD8+ T Cells after Phagocytosis of Gamma-Irradiated Melanoma Cells

PubMed Central

Barrio, María Marcela; Abes, Riad; Colombo, Marina; Pizzurro, Gabriela; Boix, Charlotte; Roberti, María Paula; Gélizé, Emmanuelle; Rodriguez-Zubieta, Mariana

2012-01-01

Dendritic cells (DC) can achieve cross-presentation of naturally-occurring tumor-associated antigens after phagocytosis and processing of dying tumor cells. They have been used in different clinical settings to vaccinate cancer patients. We have previously used gamma-irradiated MART-1 expressing melanoma cells as a source of antigens to vaccinate melanoma patients by injecting irradiated cells with BCG and GM-CSF or to load immature DC and use them as a vaccine. Other clinical trials have used IFN-gamma activated macrophage killer cells (MAK) to treat cancer patients. However, the clinical use of MAK has been based on their direct tumoricidal activity rather than on their ability to act as antigen-presenting cells to stimulate an adaptive antitumor response. Thus, in the present work, we compared the fate of MART-1 after phagocytosis of gamma-irradiated cells by clinical grade DC or MAK as well as the ability of these cells to cross present MART-1 to CD8+ T cells. Using a high affinity antibody against MART-1, 2A9, which specifically stains melanoma tumors, melanoma cell lines and normal melanocytes, the expression level of MART-1 in melanoma cell lines could be related to their ability to stimulate IFN-gamma production by a MART-1 specific HLA-A*0201-restricted CD8+ T cell clone. Confocal microscopy with Alexa Fluor®647-labelled 2A9 also showed that MART-1 could be detected in tumor cells attached and/or fused to phagocytes and even inside these cells as early as 1 h and up to 24 h or 48 h after initiation of co-cultures between gamma-irradiated melanoma cells and MAK or DC, respectively. Interestingly, MART-1 was cross-presented to MART-1 specific T cells by both MAK and DC co-cultured with melanoma gamma-irradiated cells for different time-points. Thus, naturally occurring MART-1 melanoma antigen can be taken-up from dying melanoma cells into DC or MAK and both cell types can induce specific CD8+ T cell cross-presentation thereafter. PMID:22768350

Control of DC gas flow in a single-stage double-inlet pulse tube cooler

NASA Astrophysics Data System (ADS)

Wang, C.; Thummes, G.; Heiden, C.

The use of double-inlet mode in the pulse tube cooler opens up a possibility of DC gas flow circulating around the regenerator and pulse tube. Numerical analysis shows that effects of DC flow in a single-stage pulse tube cooler are different in some aspects from that in a 4 K pulse tube cooler. For highest cooler efficiency, DC flow should be compensated to a small value, i.e. DC flow over average AC flow at regenerator inlet should be in the range -0.0013 to +0.00016. Dual valves with reversed asymmetric geometries were used for the double-inlet bypass to control the DC flow in this paper. The experiment, performed in a single-stage double-inlet pulse tube cooler, verified that the cooler performance can be significantly improved by precisely controlling the DC flow.

Interfacing a small thermophotovoltaic generator to the grid

NASA Astrophysics Data System (ADS)

Durisch, W.; Grob, B.; Mayor, J.-C.; Panitz, J.-C.; Rosselet, A.

1999-03-01

A prototype thermophotovoltaic generator and grid-interfacing device have been developed to demonstrate the feasibility of grid-connected operation. For this purpose a conventional butane burner (rated power 1.35 kWth) was equipped with a ceramic composite emitter made of rare earth oxides. A water layer between emitter and photocells was used to protect the photocells against overheating. It absorbs the nonconvertible emitter radiation and is heated up thereby. The hot water so produced in larger units of this type could be used in a primary recirculation loop to transfer heat to a secondary domestic hot water system. For the photovoltaic generator, commercial grade silicon solar cells with 16% efficiency (under standard test conditions) were used. With the radiation of the emitter, a current of 4.6 A at a maximum power point voltage of 3.3 V was produced, corresponding to a DC output of 15 W and a thermal to DC power conversion efficiency of 1.1%. A specially developed high efficiency DC/DC converter and a modified, commercially available inverter were used to feed the generated power to the local grid. Under the experimental conditions in question the DC/DC-converter and the grid-inverter had efficiencies of 98 and 91%, respectively resulting in an overall interface efficiency of 89%. From modeling of the measured electrical characteristics of the photo cell generator under solar and emitter radiation, it is concluded that the photo current was about three times higher under the filtered emitter radiation. Under these conditions the electrical losses of the photocells were significantly higher than under sunlight.

Combining parallel detection of proton echo planar spectroscopic imaging (PEPSI) measurements with a data-consistency constraint improves SNR.

PubMed

Tsai, Shang-Yueh; Hsu, Yi-Cheng; Chu, Ying-Hua; Kuo, Wen-Jui; Lin, Fa-Hsuan

2015-12-01

One major challenge of MRSI is the poor signal-to-noise ratio (SNR), which can be improved by using a surface coil array. Here we propose to exploit the spatial sensitivity of different channels of a coil array to enforce the k-space data consistency (DC) in order to suppress noise and consequently to improve MRSI SNR. MRSI data were collected using a proton echo planar spectroscopic imaging (PEPSI) sequence at 3 T using a 32-channel coil array and were averaged with one, two and eight measurements (avg-1, avg-2 and avg-8). The DC constraint was applied using a regularization parameter λ of 1, 2, 3, 5 or 10. Metabolite concentrations were quantified using LCModel. Our results show that the suppression of noise by applying the DC constraint to PEPSI reconstruction yields up to 32% and 27% SNR gain for avg-1 and avg-2 data with λ = 5, respectively. According to the reported Cramer-Rao lower bounds, the improvement in metabolic fitting was significant (p < 0.01) when the DC constraint was applied with λ ≥ 2. Using the DC constraint with λ = 3 or 5 can minimize both root-mean-square errors and spatial variation for all subjects using the avg-8 data set as reference values. Our results suggest that MRSI reconstructed with a DC constraint can save around 70% of scanning time to obtain images and spectra with similar SNRs using λ = 5. Copyright © 2015 John Wiley & Sons, Ltd.

Immunogenicity is preferentially induced in sparse dendritic cell cultures.

PubMed

Nasi, Aikaterini; Bollampalli, Vishnu Priya; Sun, Meng; Chen, Yang; Amu, Sylvie; Nylén, Susanne; Eidsmo, Liv; Rothfuchs, Antonio Gigliotti; Réthi, Bence

2017-03-09

We have previously shown that human monocyte-derived dendritic cells (DCs) acquired different characteristics in dense or sparse cell cultures. Sparsity promoted the development of IL-12 producing migratory DCs, whereas dense cultures increased IL-10 production. Here we analysed whether the density-dependent endogenous breaks could modulate DC-based vaccines. Using murine bone marrow-derived DC models we show that sparse cultures were essential to achieve several key functions required for immunogenic DC vaccines, including mobility to draining lymph nodes, recruitment and massive proliferation of antigen-specific CD4+ T cells, in addition to their TH1 polarization. Transcription analyses confirmed higher commitment in sparse cultures towards T cell activation, whereas DCs obtained from dense cultures up-regulated immunosuppressive pathway components and genes suggesting higher differentiation plasticity towards osteoclasts. Interestingly, we detected a striking up-regulation of fatty acid and cholesterol biosynthesis pathways in sparse cultures, suggesting an important link between DC immunogenicity and lipid homeostasis regulation.

Development of an efficient DC-DC SEPIC converter using wide bandgap power devices for high step-up applications

NASA Astrophysics Data System (ADS)

Al-bayati, Ali M. S.; Alharbi, Salah S.; Alharbi, Saleh S.; Matin, Mohammad

2017-08-01

A highly efficient high step-up dc-dc converter is the major requirement in the integration of low voltage renewable energy sources, such as photovoltaic panel module and fuel cell stacks, with a load or utility. This paper presents the development of an efficient dc-dc single-ended primary-inductor converter (SEPIC) for high step-up applications. Three SEPIC converters are designed and studied using different combinations of power devices: a combination based on all Si power devices using a Si-MOSFET and a Si-diode and termed as Si/Si, a combination based on a hybrid of Si and SiC power devices using the Si-MOSFET and a SiC-Schottky diode and termed as Si/SiC, and a combination based on all SiC power devices using a SiC-MOSFET and the SiC-Schottky diode and termed as SiC/SiC. The switching behavior of the Si-MOSFET and SiC-MOSFET is characterized and analyzed within the different combinations at the converter level. The effect of the diode type on the converter's overall performance is also discussed. The switching energy losses, total power losses, and the overall performance effciency of the converters are measured and reported under different switching frequencies. Furthermore, the potential of the designed converters to operate efficiently at a wide range of input voltages and output powers is studied. The analysis and results show an outstanding performance efficiency of the designed SiC/SiC based converter under a wide range of operating conditions.

Decoy receptor 3, a novel inflammatory marker, and mortality in hemodialysis patients.

PubMed

Hung, Szu-Chun; Hsu, Ta-Wei; Lin, Yao-Ping; Tarng, Der-Cherng

2012-08-01

Inflammation is closely associated with cardiovascular disease, the leading cause of mortality in patients with CKD. Serum decoy receptor 3 (DcR3) is a member of the TNF receptor superfamily. CKD patients have higher levels of DcR3 than the general population, but whether DcR3 predicts mortality in CKD patients on hemodialysis has not been explored. DcR3 levels were measured in 316 prevalent hemodialysis patients who were followed up from November 1, 2004, to June 30, 2009, for cardiovascular and all-cause mortality. The baseline DcR3 concentration showed a strong positive correlation with inflammatory markers including high-sensitivity C-reactive protein, IL-6, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). During a follow-up period of 54 months, 90 patients died (34 cardiovascular deaths). Kaplan-Meier survival analysis showed higher cardiovascular and all-cause mortality in patients with higher DcR3 levels. The hazard ratios (95% confidence intervals) of the highest versus lowest tertiles of DcR3 were 2.8 (1.1-7.3; P for trend=0.04) for cardiovascular mortality and 2.1 (1.1-3.7; P for trend=0.02) for all-cause mortality, respectively. Based on the minimal increase in the area under the receiver operating characteristic curve from 0.79 to 0.80, the addition of DcR3 to established risk factors including VCAM-1, albumin, and IL-6 does not improve the prediction of mortality. Higher DcR3 levels strongly correlate with inflammation and independently predict cardiovascular and all-cause mortality in CKD patients on hemodialysis.

Evaluation of a microwave high-power reception-conversion array for wireless power transmission

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1975-01-01

Initial performance tests of a 24-sq m area array of rectenna elements are presented. The array is used as the receiving portion of a wireless microwave power transmission engineering verification test system. The transmitting antenna was located at a range of 1.54 km. Output dc voltage and power, input RF power, efficiency, and operating temperatures were obtained for a variety of dc load and RF incident power levels at 2388 MHz. Incident peak RF intensities of up to 170 mW/sq cm yielded up to 30.4 kW of dc output power. The highest derived collection-conversion efficiency of the array was greater than 80 percent.

11. Photocopy of photograph by Commission of Fine Arts, Washington, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Photocopy of photograph by Commission of Fine Arts, Washington, DC. Date and photographer unknown. CLOSE UP OF ARMILLARY SPHERE - Meridian Hill Park, Bounded by Fifteenth, Sixteenth, Euclid & W Streets, Northwest, Washington, District of Columbia, DC

Electronic circuit provides accurate sensing and control of dc voltage

NASA Technical Reports Server (NTRS)

Loftus, W. D.

1966-01-01

Electronic circuit used relay coil to sense and control dc voltage. The control relay is driven by a switching transistor that is biased to cutoff for all input up to slightly less than the threshold level.

A Single-Phase Embedded Z-Source DC-AC Inverter

PubMed Central

Kim, Se-Jin; Lim, Young-Cheol

2014-01-01

In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

A single-phase embedded Z-source DC-AC inverter.

PubMed

Kim, Se-Jin; Lim, Young-Cheol

2014-01-01

In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively.

75 FR 27401 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-9-30, DC-9-40, and DC-9-50...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

... the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance... that this AD affects 137 airplanes of U.S. registry. We also estimate that it takes up to 8 work-hours per product to comply with this AD. The average labor rate is $85 per work-hour. Based on these...

Quasi-Linear Circuit

NASA Technical Reports Server (NTRS)

Bradley, William; Bird, Ross; Eldred, Dennis; Zook, Jon; Knowles, Gareth

2013-01-01

This work involved developing spacequalifiable switch mode DC/DC power supplies that improve performance with fewer components, and result in elimination of digital components and reduction in magnetics. This design is for missions where systems may be operating under extreme conditions, especially at elevated temperature levels from 200 to 300 degC. Prior art for radiation-tolerant DC/DC converters has been accomplished utilizing classical magnetic-based switch mode converter topologies; however, this requires specific shielding and component de-rating to meet the high-reliability specifications. It requires complex measurement and feedback components, and will not enable automatic re-optimization for larger changes in voltage supply or electrical loading condition. The innovation is a switch mode DC/DC power supply that eliminates the need for processors and most magnetics. It can provide a well-regulated voltage supply with a gain of 1:100 step-up to 8:1 step down, tolerating an up to 30% fluctuation of the voltage supply parameters. The circuit incorporates a ceramic core transformer in a manner that enables it to provide a well-regulated voltage output without use of any processor components or magnetic transformers. The circuit adjusts its internal parameters to re-optimize its performance for changes in supply voltage, environmental conditions, or electrical loading at the output

Pulsed-DC DBD Plasma Actuators

NASA Astrophysics Data System (ADS)

Duong, Alan; Corke, Thomas; Thomas, Flint

2017-11-01

A power system for dielectric barrier discharge (DBD) plasma actuators that utilizes a pulsed-DC waveform is presented. The plasma actuator arrangement is identical to most typical AC-DBD designs with staggered electrodes that are separated by a dielectric insulator. A key difference is that the pulsed-DC actuator utilizes a DC voltage source to drive the actuator instead of an AC voltage input. The DC source is supplied to both electrodes. The exposed electrode remains constant in time while the encapsulated electrode is periodically grounded for short instances then is allowed to rise to the source DC level. Further investigation of the pulsed-DC plasma actuator was conducted. Time-resolved velocity measurements were done to characterize the induced velocity field generated by the pulsed-DC plasma actuator. A model of the pulsed-DC plasma actuator is developed in LTspice for further study. The work presented are intended in developing a model to be used in CFD flow control simulations. NASA SBIR NNX14CC12C.

77 FR 36950 - Airworthiness Directives; Dassault Aviation Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-20

... time between overhauls, and required an initial overhaul, of the direct current (DC) generator... overhauls, and required an initial overhaul, of the DC generator (bearings). That NPRM resulted from... condition as: Time between overhaul (TBO) of DC [direct current] generator bearings is set at 1,000 flight...

IFN-α regulates Blimp-1 expression via miR-23a and miR-125b in both monocytes-derived DC and pDC.

PubMed

Parlato, Stefania; Bruni, Roberto; Fragapane, Paola; Salerno, Debora; Marcantonio, Cinzia; Borghi, Paola; Tataseo, Paola; Ciccaglione, Anna Rita; Presutti, Carlo; Romagnoli, Giulia; Bozzoni, Irene; Belardelli, Filippo; Gabriele, Lucia

2013-01-01

Type I interferon (IFN-I) have emerged as crucial mediators of cellular signals controlling DC differentiation and function. Human DC differentiated from monocytes in the presence of IFN-α (IFN-α DC) show a partially mature phenotype and a special capability of stimulating CD4+ T cell and cross-priming CD8+ T cells. Likewise, plasmacytoid DC (pDC) are blood DC highly specialized in the production of IFN-α in response to viruses and other danger signals, whose functional features may be shaped by IFN-I. Here, we investigated the molecular mechanisms stimulated by IFN-α in driving human monocyte-derived DC differentiation and performed parallel studies on peripheral unstimulated and IFN-α-treated pDC. A specific miRNA signature was induced in IFN-α DC and selected miRNAs, among which miR-23a and miR-125b, proved to be negatively associated with up-modulation of Blimp-1 occurring during IFN-α-driven DC differentiation. Of note, monocyte-derived IFN-α DC and in vitro IFN-α-treated pDC shared a restricted pattern of miRNAs regulating Blimp-1 expression as well as some similar phenotypic, molecular and functional hallmarks, supporting the existence of a potential relationship between these DC populations. On the whole, these data uncover a new role of Blimp-1 in human DC differentiation driven by IFN-α and identify Blimp-1 as an IFN-α-mediated key regulator potentially accounting for shared functional features between IFN-α DC and pDC.

IFN-α Regulates Blimp-1 Expression via miR-23a and miR-125b in Both Monocytes-Derived DC and pDC

PubMed Central

Parlato, Stefania; Salerno, Debora; Marcantonio, Cinzia; Borghi, Paola; Tataseo, Paola; Ciccaglione, Anna Rita; Presutti, Carlo; Romagnoli, Giulia; Bozzoni, Irene; Belardelli, Filippo; Gabriele, Lucia

2013-01-01

Type I interferon (IFN-I) have emerged as crucial mediators of cellular signals controlling DC differentiation and function. Human DC differentiated from monocytes in the presence of IFN-α (IFN-α DC) show a partially mature phenotype and a special capability of stimulating CD4+ T cell and cross-priming CD8+ T cells. Likewise, plasmacytoid DC (pDC) are blood DC highly specialized in the production of IFN-α in response to viruses and other danger signals, whose functional features may be shaped by IFN-I. Here, we investigated the molecular mechanisms stimulated by IFN-α in driving human monocyte-derived DC differentiation and performed parallel studies on peripheral unstimulated and IFN-α-treated pDC. A specific miRNA signature was induced in IFN-α DC and selected miRNAs, among which miR-23a and miR-125b, proved to be negatively associated with up-modulation of Blimp-1 occurring during IFN-α-driven DC differentiation. Of note, monocyte-derived IFN-α DC and in vitro IFN-α-treated pDC shared a restricted pattern of miRNAs regulating Blimp-1 expression as well as some similar phenotypic, molecular and functional hallmarks, supporting the existence of a potential relationship between these DC populations. On the whole, these data uncover a new role of Blimp-1 in human DC differentiation driven by IFN-α and identify Blimp-1 as an IFN-α-mediated key regulator potentially accounting for shared functional features between IFN-α DC and pDC. PMID:23977359

High-performance fractional order terminal sliding mode control strategy for DC-DC Buck converter

PubMed Central

Xu, Dan; Zhou, Huan; Bai, Anning; Lu, Wei

2017-01-01

This paper presents an adaption of the fractional order terminal sliding mode control (AFTSMC) strategy for DC-DC Buck converter. The following strategy aims to design a novel nonlinear sliding surface function, with a double closed-loop structure of voltage and current. This strategy is a fusion of two characteristics: terminal sliding mode control (TSMC) and fractional order calculation (FOC). In addition, the influence of “the controller parameters” on the “performance of double closed-loop system” is investigated. It is observed that the value of terminal power has to be chosen to make a compromise between start-up and transient response of the converter. Therefore the AFTSMC strategy chooses the value of the terminal power adaptively, and this strategy can lead to the appropriate number of fractional order as well. Furthermore, through the fractional order analysis, the system can reach the sliding mode surface in a finite time. And the theoretical considerations are verified by numerical simulation. The performance of the AFTSMC and TSMC strategies is tested by computer simulations. And the comparison simulation results show that the AFTSMC exhibits a considerable improvement in terms of a faster output voltage response during load changes. Moreover, AFTSMC obtains a faster dynamical response, smaller steady-state error rate and lower overshoot. PMID:29084255

A 1 MW, 100 kV, less than 100 kg space based dc-dc power converter

NASA Technical Reports Server (NTRS)

Cooper, J. R.; White, C. W.

1991-01-01

A 1 MW dc-dc power converter has been designed which has an input voltage of 5 kV +/-3 percent, an output voltage of 100 kV +/- 0.25 percent, and a run time of 1000 s at full power. The estimated system mass is 83.8 kg, giving a power density of 11.9 kW/kg. The system exceeded the weight goal of 10 kW/kg through the use of innovative components and system concepts. The system volume is approximately 0.1 cu m, and the overall system efficiency is estimated to be 87 percent. Some of the unique system features include a 50-kHz H-bridge inverter using MOS-controlled thyristors as the switching devices, a resonance transformer to step up the voltage, open-cycle cryogenic hydrogen gas cooling, and a nonrigid, inflatable housing which provides on-demand pressurization of the power converter local environment. This system scales very well to higher output powers. The weight of the 10-MW system with the same input and output voltage requirements and overall system configuration is estimated to be 575.3 kg. This gives a power density of 17.4 kW/kg, significantly higher than the 11.9 kW/kg estimated at 1 MW.

High-performance fractional order terminal sliding mode control strategy for DC-DC Buck converter.

PubMed

Wang, Jianlin; Xu, Dan; Zhou, Huan; Bai, Anning; Lu, Wei

2017-01-01

This paper presents an adaption of the fractional order terminal sliding mode control (AFTSMC) strategy for DC-DC Buck converter. The following strategy aims to design a novel nonlinear sliding surface function, with a double closed-loop structure of voltage and current. This strategy is a fusion of two characteristics: terminal sliding mode control (TSMC) and fractional order calculation (FOC). In addition, the influence of "the controller parameters" on the "performance of double closed-loop system" is investigated. It is observed that the value of terminal power has to be chosen to make a compromise between start-up and transient response of the converter. Therefore the AFTSMC strategy chooses the value of the terminal power adaptively, and this strategy can lead to the appropriate number of fractional order as well. Furthermore, through the fractional order analysis, the system can reach the sliding mode surface in a finite time. And the theoretical considerations are verified by numerical simulation. The performance of the AFTSMC and TSMC strategies is tested by computer simulations. And the comparison simulation results show that the AFTSMC exhibits a considerable improvement in terms of a faster output voltage response during load changes. Moreover, AFTSMC obtains a faster dynamical response, smaller steady-state error rate and lower overshoot.

A 1 MW, 100 kV, less than 100 kg space based dc-dc power converter

NASA Astrophysics Data System (ADS)

Cooper, J. R.; White, C. W.

A 1 MW dc-dc power converter has been designed which has an input voltage of 5 kV +/-3 percent, an output voltage of 100 kV +/- 0.25 percent, and a run time of 1000 s at full power. The estimated system mass is 83.8 kg, giving a power density of 11.9 kW/kg. The system exceeded the weight goal of 10 kW/kg through the use of innovative components and system concepts. The system volume is approximately 0.1 cu m, and the overall system efficiency is estimated to be 87 percent. Some of the unique system features include a 50-kHz H-bridge inverter using MOS-controlled thyristors as the switching devices, a resonance transformer to step up the voltage, open-cycle cryogenic hydrogen gas cooling, and a nonrigid, inflatable housing which provides on-demand pressurization of the power converter local environment. This system scales very well to higher output powers. The weight of the 10-MW system with the same input and output voltage requirements and overall system configuration is estimated to be 575.3 kg. This gives a power density of 17.4 kW/kg, significantly higher than the 11.9 kW/kg estimated at 1 MW.

Technical Advance: Live-imaging analysis of human dendritic cell migrating behavior under the influence of immune-stimulating reagents in an organotypic model of lung

PubMed Central

Nguyen Hoang, Anh Thu; Chen, Puran; Björnfot, Sofia; Högstrand, Kari; Lock, John G.; Grandien, Alf; Coles, Mark; Svensson, Mattias

2014-01-01

This manuscript describes technical advances allowing manipulation and quantitative analyses of human DC migratory behavior in lung epithelial tissue. DCs are hematopoietic cells essential for the maintenance of tissue homeostasis and the induction of tissue-specific immune responses. Important functions include cytokine production and migration in response to infection for the induction of proper immune responses. To design appropriate strategies to exploit human DC functional properties in lung tissue for the purpose of clinical evaluation, e.g., candidate vaccination and immunotherapy strategies, we have developed a live-imaging assay based on our previously described organotypic model of the human lung. This assay allows provocations and subsequent quantitative investigations of DC functional properties under conditions mimicking morphological and functional features of the in vivo parental tissue. We present protocols to set up and prepare tissue models for 4D (x, y, z, time) fluorescence-imaging analysis that allow spatial and temporal studies of human DCs in live epithelial tissue, followed by flow cytometry analysis of DCs retrieved from digested tissue models. This model system can be useful for elucidating incompletely defined pathways controlling DC functional responses to infection and inflammation in lung epithelial tissue, as well as the efficacy of locally administered candidate interventions. PMID:24899587

C-reactive protein-to-albumin ratio is a predictor of hepatitis B virus related decompensated cirrhosis: time-dependent receiver operating characteristics and decision curve analysis.

PubMed

Huang, Si-Si; Xie, Dong-Mei; Cai, Yi-Jing; Wu, Jian-Min; Chen, Rui-Chong; Wang, Xiao-Dong; Song, Mei; Zheng, Ming-Hua; Wang, Yu-Qun; Lin, Zhuo; Shi, Ke-Qing

2017-04-01

Hepatitis B virus (HBV) infection remains a major health problem and HBV-related-decompensated cirrhosis (HBV-DC) usually leads to a poor prognosis. Our aim was to determine the utility of inflammatory biomarkers in predicting mortality of HBV-DC. A total of 329 HBV-DC patients were enrolled. Survival estimates for the entire study population were generated using the Kaplan-Meier method. The prognostic values for model for end-stage liver disease (MELD) score, Child-Pugh score, and inflammatory biomarkers neutrophil/lymphocyte ratio, C-reactive protein-to-albumin ratio (CAR), and lymphocyte-to-monocyte ratio (LMR) for HBV-DC were compared using time-dependent receiver operating characteristic curves and time-dependent decision curves. The survival time was 23.1±15.8 months. Multivariate analysis identified age, CAR, LMR, and platelet count as prognostic independent risk factors. Kaplan-Meier analysis indicated that CAR of at least 1.0 (hazard ratio, 7.19; 95% confidence interval, 4.69-11.03), and LMR less than 1.9 (hazard ratio, 2.40; 95% confidence interval, 1.69-3.41) were independently associated with mortality of HBV-DC. The time-dependent receiver operating characteristic indicated that CAR showed the best performance in predicting mortality of HBV-DC compared with LMR, MELD score, and Child-Pugh score. The results were also confirmed by time-dependent decision curves. CAR and LMR were associated with the prognosis of HBV-DC. CAR was superior to LMR, MELD score, and Child-Pugh score in HBV-DC mortality prediction.

Technical advance: Generation of human pDC equivalents from primary monocytes using Flt3-L and their functional validation under hypoxia.

PubMed

Sekar, Divya; Brüne, Bernhard; Weigert, Andreas

2010-08-01

The division of labor between DC subsets is evolutionarily well-defined. mDC are efficient in antigen presentation, whereas pDC act as rheostats of the immune system. They activate NK cells, cause bystander activation of mDC, and interact with T cells to induce tolerance. This ambiguity positions pDC at the center of inflammatory diseases, such as cancer, arthritis, and autoimmune diseases. The ability to generate human mDC ex vivo made it possible to engineer them to suit therapy needs. Unfortunately, a similar, easily accessible system to generate human pDC is not available. We describe a method to generate human pDC equivalents ex vivo, termed mo-pDC from peripheral blood monocytes using Flt3-L. mo-pDC showed a characteristic pDC profile, such as high CD123 and BDCA4, but low CD86 and TLR4 surface expression and a low capacity to induce autologous lymphocyte proliferation and to phagocytose apoptotic debris in comparison with mDC. Interestingly, mo-pDC up-regulated the pDC lineage-determining transcription factor E2-2 as well as expression of BDCA2, which is under the transcriptional control of E2-2 but not its inhibitor ID2, during differentiation. mo-pDC produced high levels of IFN-alpha when pretreated overnight with TNF-alpha. Under hypoxia, E2-2 was down-regulated, and ID2 was induced in mo-pDC, whereas surface expression of MHCI, CD86, and BDCA2 was decreased. Furthermore, mo-pDC produced high levels of inflammatory cytokines when differentiated under hypoxia compared with normoxia. Hence, mo-pDC can be used to study differentiation and functions of human pDC under microenvironmental stimuli.

DC motor speed control using fuzzy logic controller

NASA Astrophysics Data System (ADS)

Ismail, N. L.; Zakaria, K. A.; Nazar, N. S. Moh; Syaripuddin, M.; Mokhtar, A. S. N.; Thanakodi, S.

2018-02-01

The automatic control has played a vital role in the advance of engineering and science. Nowadays in industries, the control of direct current (DC) motor is a common practice thus the implementation of DC motor controller speed is important. The main purpose of motor speed control is to keep the rotation of the motor at the present speed and to drive a system at the demand speed. The main purpose of this project is to control speed of DC Series Wound Motor using Fuzzy Logic Controller (FLC). The expectation of this project is the Fuzzy Logic Controller will get the best performance compared to dc motor without controller in terms of settling time (Ts), rise time (Tr), peak time (Tp) and percent overshoot (%OS).

Enhanced cell trapping throughput using DC-biased AC electric field in a dielectrophoresis-based fluidic device with densely packed silica beads.

PubMed

Lewpiriyawong, Nuttawut; Xu, Guolin; Yang, Chun

2018-03-01

This paper presents the use of DC-biased AC electric field for enhancing cell trapping throughput in an insulator-based dielectrophoretic (iDEP) fluidic device with densely packed silica beads. Cell suspension is carried through the iDEP device by a pressure-driven flow. Under an applied DC-biased AC electric field, DEP trapping force is produced as a result of non-uniform electric field induced by the gap of electrically insulating silica beads packed between two mesh electrodes that allow both fluid and cells to pass through. While the AC component is mainly to control the magnitude of DEP trapping force, the DC component generates local electroosmotic (EO) flow in the cavity between the beads and the EO flow can be set to move along or against the main pressure-driven flow. Our experimental and simulation results show that desirable trapping is achieved when the EO flow direction is along (not against) the main flow direction. Using our proposed DC-biased AC field, the device can enhance the trapping throughput (in terms of the flowrate of cell suspension) up to five times while yielding almost the same cell capture rates as compared to the pure AC field case. Additionally, the device was demonstrated to selectively trap dead yeast cells from a mixture of flowing live and dead yeast cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dealing with the health state 'dead' when using discrete choice experiments to obtain values for EQ-5D-5L heath states.

PubMed

Ramos-Goñi, Juan Manuel; Rivero-Arias, Oliver; Errea, María; Stolk, Elly A; Herdman, Michael; Cabasés, Juan Manuel

2013-07-01

To evaluate two different methods to obtain a dead (0)--full health (1) scale for EQ-5D-5L valuation studies when using discrete choice (DC) modeling. The study was carried out among 400 respondents from Barcelona who were representative of the Spanish population in terms of age, sex, and level of education. The DC design included 50 pairs of health states in five blocks. Participants were forced to choose between two EQ-5D-5L states (A and B). Two extra questions concerned whether A and B were considered worse than dead. Each participant performed ten choice exercises. In addition, values were collected using lead-time trade-off (lead-time TTO), for which 100 states in ten blocks were selected. Each participant performed five lead-time TTO exercises. These consisted of DC models offering the health state 'dead' as one of the choices--for which all participants' responses were used (DCdead)--and a model that included only the responses of participants who chose at least one state as worse than dead (WTD) (DCWTD). The study also estimated DC models rescaled with lead-time TTO data and a lead-time TTO linear model. The DC(dead) and DCWTD models produced relatively similar results, although the coefficients in the DCdead model were slightly lower. The DC model rescaled with lead-time TTO data produced higher utility decrements. Lead-time TTO produced the highest utility decrements. The incorporation of the state 'dead' in the DC models produces results in concordance with DC models that do not include 'dead'.

Clean Air Interstate Rule: Changes and Modeling in AEO2010 (released in AEO2010)

EIA Publications

2010-01-01

On December 23, 2008, the D.C. Circuit Court remanded but did not vacate the Clean Air Interstate Rule (CAIR), overriding its previous decision on February 8, 2008, to remand and vacate CAIR. The December decision, which is reflected in Annual Energy Outlook 2010 (AEO) , allows CAIR to remain in effect, providing time for the Environmental Protection Agency to modify the rule in order to address objections raised by the Court in its earlier decision. A similar rule, referred to as the Clean Air Mercury Rule (CAMR), which was to set up a cap-and-trade system for reducing mercury emissions by approximately 70%, is not represented in the AEO2010 projections, because it was vacated by the D.C. Circuit Court in February 2008.

Light-weight DC to very high voltage DC converter

DOEpatents

Druce, Robert L.; Kirbie, Hugh C.; Newton, Mark A.

1998-01-01

A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

Experimental demonstration of real-time adaptively modulated DDO-OFDM systems with a high spectral efficiency up to 5.76bit/s/Hz transmission over SMF links.

PubMed

Chen, Ming; He, Jing; Tang, Jin; Wu, Xian; Chen, Lin

2014-07-28

In this paper, a FPGAs-based real-time adaptively modulated 256/64/16QAM-encoded base-band OFDM transceiver with a high spectral efficiency up to 5.76bit/s/Hz is successfully developed, and experimentally demonstrated in a simple intensity-modulated direct-detection optical communication system. Experimental results show that it is feasible to transmit a raw signal bit rate of 7.19Gbps adaptively modulated real-time optical OFDM signal over 20km and 50km single mode fibers (SMFs). The performance comparison between real-time and off-line digital signal processing is performed, and the results show that there is a negligible power penalty. In addition, to obtain the best transmission performance, direct-current (DC) bias voltage for MZM and launch power into optical fiber links are explored in the real-time optical OFDM systems.

AGOR 28: SIO Shipyard Representative Bi-Weekly Progress Report

DTIC Science & Technology

2015-08-27

the main deck DC equipment out of the deck locker and down to the first platform to provide better separation from DC Locker 1 and to provide better...access to the main machinery space aft. This also frees up space in the deck locker which was limited to start with. The following areas...of responsibility were identified by the government: Alion responsibility: - Update FCP with following changes - Move DC locker #2 from main

A brief review of models of DC-DC power electronic converters for analysis of their stability

NASA Astrophysics Data System (ADS)

Siewniak, Piotr; Grzesik, Bogusław

2014-10-01

A brief review of models of DC-DC power electronic converters (PECs) is presented in this paper. It contains the most popular, continuous-time and discrete-time models used for PEC simulation, design, stability analysis and other applications. Both large-signal and small-signal models are considered. Special attention is paid to models that are used in practice for the analysis of the global and local stability of PECs.

75 FR 33515 - Federal Motor Vehicle Safety Standards; Electric-Powered Vehicles; Electrolyte Spillage and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-14

..., and made a simple comparison. Based on the IEC report, the human body can withstand up to four times....\\3\\ The flow of this amount of AC through the human body may result in perception of the current and... considered to be safe) corresponds to 8 mA of DC (that is also considered to be safe for the human body).\\4...

Prognosis of 1169 hepatitis C chronically infected patients with decompensated cirrhosis in the predirect-acting antiviral era.

PubMed

McDonald, S A; Innes, H A; Aspinall, E; Hayes, P C; Alavi, M; Valerio, H; Goldberg, D J; Hutchinson, S J

2017-04-01

At a population level, little is known regarding the risk of liver- and nonliver-related mortality and hospitalization and the development of hepatocellular carcinoma (HCC) in hepatitis C virus (HCV)-infected patients with decompensated cirrhosis (DC). This large-scale national record-linkage study estimates these outcomes following first hospital admission for DC. Record-linkages between national HCV diagnosis and clinical databases and the national inpatient hospital episode database and mortality register were conducted to follow-up the disease course of all identified HCV-diagnosed and chronically infected persons. The study population consisted of 1169 HCV chronically infected persons who had a first hospital admission for DC within the period 1994-2013. We observed an overall average annual percentage change of 12.6% in new DC patients (from 63 in 1994-1999 to 541 in 2009-2013), with no evidence for any improvement in the relative risks of liver-related or all-cause death over time. Between 1 January 1994 and 31 May 2014, 722 and 95 DC patients had died of a liver- and a nonliver-related cause, respectively, and 106 patients had a subsequent first admission for HCC. The 5-year cumulative incidence of liver-related mortality, nonliver-related mortality and first subsequent HCC admission was 61.3%, 8.2% and 8.8%, respectively. The health burden in HCV-infected patients associated with development of decompensated cirrhosis has increased dramatically over the last 20 years. Our findings establish the baseline mortality and HCC progression rates in DC patients against which the impact of new antiviral therapies can be measured. © 2016 John Wiley & Sons Ltd.

High hydrostatic pressure affects antigenic pool in tumor cells: Implication for dendritic cell-based cancer immunotherapy.

PubMed

Urbanova, Linda; Hradilova, Nada; Moserova, Irena; Vosahlikova, Sarka; Sadilkova, Lenka; Hensler, Michal; Spisek, Radek; Adkins, Irena

2017-07-01

High hydrostatic pressure (HHP) can be used to generate dendritic cell (DC)-based active immunotherapy for prostate, lung and ovarian cancer. We showed here that HHP treatment of selected human cancer cell lines leads to a degradation of tumor antigens which depends on the magnitude of HHP applied and on the cancer cell line origin. Whereas prostate or ovarian cell lines displayed little protein antigen degradation with HHP treatment up to 300MPa after 2h, tumor antigens are hardly detected in lung cancer cell line after treatment with HHP 250MPa at the same time. On the other hand, quick reduction of tumor antigen-coding mRNA was observed at HHP 200MPa immediately after treatment in all cell lines tested. To optimize the DC-based active cellular therapy protocol for HHP-sensitive cell lines the immunogenicity of HHP-treated lung cancer cells at 150, 200 and 250MPa was compared. Lung cancer cells treated with HHP 150MPa display characteristics of immunogenic cell death, however cells are not efficiently phagocytosed by DC. Despite induction of the highest number of antigen-specific CD8 + T cells, 150 MPa-treated lung cancer cells survive in high numbers. This excludes their use in DC vaccine manufacturing. HHP of 200MPa treatment of lung cancer cells ensures the optimal ratio of efficient immunogenic killing and delivery of protein antigens in DC. These results represent an important pre-clinical data for generation of immunogenic killed lung cancer cells in ongoing NSCLC Phase I/II clinical trial using DC-based active cellular immunotherapy (DCVAC/LuCa). Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

Development of a 1000V, 200A, low-loss, fast-switching, gate-assisted turn-off thyristor

NASA Technical Reports Server (NTRS)

Schlegel, E. S.; Lowry, L. R.; Moore, D. L.

1977-01-01

The results of a program to develop a fast high power thyristor that can operate in switching circuits at frequencies of 10 to 20 kHz with very low power loss are given. Feasibility was demonstrated for a thyristor that blocks 1000V forward and reverse, conducts 200A, turns on in little more than 2 more microseconds with only 2A of gate drive, turns off in 3 microseconds with 2A of gate assist current and has an energy dissipation of only 12 mJ per pulse for a 20 microsecond half sine wave 200A pulse. Data were generated that clearly showed the tradeoffs that can be made between the turn off time and forward drop. The understanding of this relationship is necessary in the selection of deliverable thyristors with turn off times up to 7 microseconds to give improved efficiency in a series resonant dc to dc inverter application.

Experimental verification of internal parameter in magnetically coupled boost used as PV optimizer in parallel association

NASA Astrophysics Data System (ADS)

Sawicki, Jean-Paul; Saint-Eve, Frédéric; Petit, Pierre; Aillerie, Michel

2017-02-01

This paper presents results of experiments aimed to verify a formula able to compute duty cycle in the case of pulse width modulation control for a DC-DC converter designed and realized in laboratory. This converter, called Magnetically Coupled Boost (MCB) is sized to step up only one photovoltaic module voltage to supply directly grid inverters. Duty cycle formula will be checked in a first time by identifying internal parameter, auto-transformer ratio, and in a second time by checking stability of operating point on the side of photovoltaic module. Thinking on nature of generator source and load connected to converter leads to imagine additional experiments to decide if auto-transformer ratio parameter could be used with fixed value or on the contrary with adaptive value. Effects of load variations on converter behavior or impact of possible shading on photovoltaic module are also mentioned, with aim to design robust control laws, in the case of parallel association, designed to compensate unwanted effects due to output voltage coupling.

Direct measurement of the breakdown slip from near-fault strong motion data

NASA Astrophysics Data System (ADS)

Cruz-Atienza, V. M.; Olsen, K. B.; Dalguer, L. A.

2007-12-01

Obtaining reliable estimates of the frictional behaviour on earthquake faults is a fundamental task, particularly the breakdown slip Dc, which has an important role on rupture propagation through the earthquake energy budget. Several studies have attempted to estimate Dc indirectly from kinematical analysis of fault ruptures (e.g., Ide and Takeo, JGR, 1997). However, such estimates are complicated because of both the limited band-width of the observed seismograms used to image the rupture process and the rapid decay of high frequencies with distance from the fault. Mikumo et al. (BSSA, 2003) proposed a method to estimate Dc on the fault plane as the slip at the time of the peak sliprate function (Dc'). Fukuyama and Mikumo (GRL, 2007) proposed to extend this method beyond the fault plane, by estimating Dc as twice the rake-parallel particle displacement at the time of the peak particle velocity. The factor of two arises from an equal amount of opposite displacement on either side of the fault. They concluded that such method allows reliable Dc' estimates with negligible dependence on the perpendicular distance from the fault, and used it to obtain Dc' estimates for the 2000 M6.6 Tottori (0.3 m) and the 2002 M7.9 Denali (2.5 m) earthquakes. The study by Fukuyama and Mikumo was based on simple two-dimensional Green's functions in a homogeneous full space for an anti-plane kinematic crack, and suffers from three fundamental omissions: 1) the free surface and heterogeneous structure, 2) the finiteness of the rupture surface and 3) the dynamic rupture complexity of real 3D earthquakes. Here, we re-examine the methodology proposed by Fukuyama and Mikumo by means of a more realistic approach. We use spontaneous rupture propagation simulated by a recently developed and highly accurate approach, namely the staggered-grid split-node (SGSN) method in a fourth-order staggered- grid finite difference method (Dalguer and Day, JGR, 2007). We assume a vertical strike-slip fault governed by both linear and non-linear slip-weakening friction laws. Our results show that both the free surface and the stopping phases strongly affect Dc estimates. The particle motion recorded by surface instruments is amplified roughly by a factor of two due to the presence of the free surface. As a consequence, the method by Fukuyama and Mikumo over-estimates Dc when applied to strong motion data recorded on the earth's surface. Moreover, contrary to the results by Fukuyama and Mikumo, we observe a strong distance-dependence of the Dc estimates perpendicular to the fault. This variation includes a minimum near the fault, increasing up to about 140% of the target Dc value at a distance 2-3 km from the fault. At further distances from the fault the Dc estimate decreases to about 60% of the target value 10 km away. This distance dependence of the Dc estimate is presumably caused mainly by stopping phases propagating from the fault boundaries. Simulations in heterogeneous media including a low-velocity layer, intrinsic attenuation (Q) and stochastic initial stress conditions allow us to asses the reliability and uncertainty involved in the method proposed by Fukuyama and Mikumo. Dc estimates under these realistic conditions are important but remain below a factor of two in most of the cases we have analyzed. In summary, the accuracy of the method is strongly affected by the presence of the free surface, finite fault extent, and likely by complexity in the velocity structure and rupture propagation.

Immunogenicity is preferentially induced in sparse dendritic cell cultures

PubMed Central

Nasi, Aikaterini; Bollampalli, Vishnu Priya; Sun, Meng; Chen, Yang; Amu, Sylvie; Nylén, Susanne; Eidsmo, Liv; Rothfuchs, Antonio Gigliotti; Réthi, Bence

2017-01-01

We have previously shown that human monocyte-derived dendritic cells (DCs) acquired different characteristics in dense or sparse cell cultures. Sparsity promoted the development of IL-12 producing migratory DCs, whereas dense cultures increased IL-10 production. Here we analysed whether the density-dependent endogenous breaks could modulate DC-based vaccines. Using murine bone marrow-derived DC models we show that sparse cultures were essential to achieve several key functions required for immunogenic DC vaccines, including mobility to draining lymph nodes, recruitment and massive proliferation of antigen-specific CD4+ T cells, in addition to their TH1 polarization. Transcription analyses confirmed higher commitment in sparse cultures towards T cell activation, whereas DCs obtained from dense cultures up-regulated immunosuppressive pathway components and genes suggesting higher differentiation plasticity towards osteoclasts. Interestingly, we detected a striking up-regulation of fatty acid and cholesterol biosynthesis pathways in sparse cultures, suggesting an important link between DC immunogenicity and lipid homeostasis regulation. PMID:28276533

Ultrasensitive hydrogen sensor based on Pt-decorated WO₃ nanorods prepared by glancing-angle dc magnetron sputtering.

PubMed

Horprathum, M; Srichaiyaperk, T; Samransuksamer, B; Wisitsoraat, A; Eiamchai, P; Limwichean, S; Chananonnawathorn, C; Aiempanakit, K; Nuntawong, N; Patthanasettakul, V; Oros, C; Porntheeraphat, S; Songsiriritthigul, P; Nakajima, H; Tuantranont, A; Chindaudom, P

2014-12-24

In this work, we report an ultrasensitive hydrogen (H2) sensor based on tungsten trioxide (WO3) nanorods decorated with platinum (Pt) nanoparticles. WO3 nanorods were fabricated by dc magnetron sputtering with a glancing angle deposition (GLAD) technique, and decorations of Pt nanoparticles were performed by normal dc sputtering on WO3 nanorods with varying deposition time from 2.5 to 15 s. Crystal structures, morphologies, and chemical information on Pt-decorated WO3 nanorods were characterized by grazing-incident X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and photoelectron spectroscopy, respectively. The effect of the Pt nanoparticles on the H2-sensing performance of WO3 nanorods was investigated over a low concentration range of 150-3000 ppm of H2 at 150-350 °C working temperatures. The results showed that the H2 response greatly increased with increasing Pt-deposition time up to 10 s but then substantially deteriorated as the deposition time increased further. The optimally decorated Pt-WO3 nanorod sensor exhibited an ultrahigh H2 response from 1530 and 214,000 to 150 and 3000 ppm of H2, respectively, at 200 °C. The outstanding gas-sensing properties may be attributed to the excellent dispersion of fine Pt nanoparticles on WO3 nanorods having a very large effective surface area, leading to highly effective spillover of molecular hydrogen through Pt nanoparticles onto the WO3 nanorod surface.

Specification, Measurement, and Control of Electrical Switching Transients

NASA Technical Reports Server (NTRS)

Javor, K.

1999-01-01

There have been several instances of susceptibility to switching transients. The Space Shuttle Spacelab Remote Acquisition Unit (RAU-A standard interface between Spacelab payloads and the Shuttle communications system) will shut down if the input 28 Vdc bus drops below 22 volts for more than 80 gs. Although a MIL-STD-461 derivative CS06 requirement was levied on the RAU, it failed to find this susceptibility. A heavy payload on one aircraft sags the 28 volt bus below 20 volts for milliseconds. Dc-dc converters have an operating voltage. A typical 28 Vdc-to-5 Vdc converter operates within tolerance when input potential is between 17-40 Vdc, A hold-up capacitor can be used to extend the time this range is presented to the convener when the line potential sags or surges outside this range. The designer must know the range of normal transients in order to choose the correct value of hold-up. This report describes the phenomena of electrical power bus transients induced by the switching of loads both on and off the bus, and control thereof.

Fast, accurate semiempirical molecular orbital calculations for macromolecules

NASA Astrophysics Data System (ADS)

Dixon, Steven L.; Merz, Kenneth M., Jr.

1997-07-01

A detailed review of the semiempirical divide-and-conquer (D&C) method is given, including a new approach to subsetting, which involves dual buffer regions. Comparisons are drawn between this method and other semiempirical macromolecular schemes. D&C calculations are carried out using a basic 32 Mbyte memory workstation on a variety of peptide systems, including proteins containing up to 1960 atoms. Aspects of storage and SCF convergence are addressed, and parallelization of the D&C algorithm is discussed.

UHF front-end feeding RFID-based body sensor networks by exploiting the reader signal

NASA Astrophysics Data System (ADS)

Pasca, M.; Colella, R.; Catarinucci, L.; Tarricone, L.; D'Amico, S.; Baschirotto, A.

2016-05-01

This paper presents an integrated, high-sensitivity UHF radio frequency identification (RFID) power management circuit for body sensor network applications. The circuit consists of a two-stage RF-DC Dickson's rectifier followed by an integrated five-stage DC-DC Pelliconi's charge pump driven by an ultralow start-up voltage LC oscillator. The DC-DC charge pump interposed between the RF-DC rectifier and the output load provides the RF to load isolation avoiding losses due to the diodes reverse saturation current. The RF-DC rectifier has been realized on FR4 substrate, while the charge pump and the oscillator have been realized in 180 nm complementary metal oxide semiconductor (CMOS) technology. Outdoor measurements demonstrate the ability of the power management circuit to provide 400 mV output voltage at 14 m distance from the UHF reader, in correspondence of -25 dBm input signal power. As demonstrated in the literature, such output voltage level is suitable to supply body sensor network nodes.

Mathematical model for the dc-ac inverter for the Space Shuttle

NASA Technical Reports Server (NTRS)

Berry, Frederick C.

1987-01-01

The reader is informed of what was done for the mathematical modeling of the dc-ac inverter for the Space Shuttle. The mathematical modeling of the dc-ac inverter is an essential element in the modeling of the electrical power distribution system of the Space Shuttle. The electrical power distribution system which is present on the Space Shuttle is made up to 3 strings each having a fuel cell which provides dc to those systems which require dc, and the inverters which convert the dc to ac for those elements which require ac. The inverters are units which are 2 wire structures for the main dc inputs and 2 wire structures for the ac output. When 3 are connected together a 4 wire wye connection results on the ac side. The method of modeling is performed by using a Least Squares curve fitting method. A computer program is presented for implementation of the model along with graphs and tables to demonstrate the accuracy of the model.

The BepiColombo Laser Altimeter (BeLA) power converter module (PCM): Concept and characterisation.

PubMed

Rodrigo, J; Gasquet, E; Castro, J-M; Herranz, M; Lara, L-M; Muñoz, M; Simon, A; Behnke, T; Thomas, N

2017-03-01

This paper presents the principal considerations when designing DC-DC converters for space instruments, in particular for the power converter module as part of the first European space laser altimeter: "BepiColombo Laser Altimeter" on board the European Space Agency-Japan Aerospace Exploration Agency (JAXA) mission BepiColombo. The main factors which determine the design of the DC-DC modules in space applications are printed circuit board occupation, mass, DC-DC converter efficiency, and environmental-survivability constraints. Topics included in the appropriated DC-DC converter design flow are hereby described. The topology and technology for the primary and secondary stages, input filters, transformer design, and peripheral components are discussed. Component selection and design trade-offs are described. Grounding, load and line regulation, and secondary protection circuitry (under-voltage, over-voltage, and over-current) are then introduced. Lastly, test results and characterization of the final flight design are also presented. Testing of the inrush current, the regulated output start-up, and the switching function of the power supply indicate that these performances are fully compliant with the requirements.

A simulation-based efficiency comparison of AC and DC power distribution networks in commercial buildings

DOE PAGES

Gerber, Daniel L.; Vossos, Vagelis; Feng, Wei; ...

2017-06-12

Direct current (DC) power distribution has recently gained traction in buildings research due to the proliferation of on-site electricity generation and battery storage, and an increasing prevalence of internal DC loads. The research discussed in this paper uses Modelica-based simulation to compare the efficiency of DC building power distribution with an equivalent alternating current (AC) distribution. The buildings are all modeled with solar generation, battery storage, and loads that are representative of the most efficient building technology. A variety of paramet ric simulations determine how and when DC distribution proves advantageous. These simulations also validate previous studies that use simplermore » approaches and arithmetic efficiency models. This work shows that using DC distribution can be considerably more efficient: a medium sized office building using DC distribution has an expected baseline of 12% savings, but may also save up to 18%. In these results, the baseline simulation parameters are for a zero net energy (ZNE) building that can island as a microgrid. DC is most advantageous in buildings with large solar capacity, large battery capacity, and high voltage distribution.« less

A simulation-based efficiency comparison of AC and DC power distribution networks in commercial buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerber, Daniel L.; Vossos, Vagelis; Feng, Wei

Direct current (DC) power distribution has recently gained traction in buildings research due to the proliferation of on-site electricity generation and battery storage, and an increasing prevalence of internal DC loads. The research discussed in this paper uses Modelica-based simulation to compare the efficiency of DC building power distribution with an equivalent alternating current (AC) distribution. The buildings are all modeled with solar generation, battery storage, and loads that are representative of the most efficient building technology. A variety of paramet ric simulations determine how and when DC distribution proves advantageous. These simulations also validate previous studies that use simplermore » approaches and arithmetic efficiency models. This work shows that using DC distribution can be considerably more efficient: a medium sized office building using DC distribution has an expected baseline of 12% savings, but may also save up to 18%. In these results, the baseline simulation parameters are for a zero net energy (ZNE) building that can island as a microgrid. DC is most advantageous in buildings with large solar capacity, large battery capacity, and high voltage distribution.« less

A Standalone Solar Photovoltaic Power Generation using Cuk Converter and Single Phase Inverter

NASA Astrophysics Data System (ADS)

Verma, A. K.; Singh, B.; Kaushika, S. C.

2013-03-01

In this paper, a standalone solar photovoltaic (SPV) power generating system is designed and modeled using a Cuk dc-dc converter and a single phase voltage source inverter (VSI). In this system, a dc-dc boost converter boosts a low voltage of a PV array to charge a battery at 24 V using a maximum power point tracking control algorithm. To step up a 24 V battery voltage to 360 V dc, a high frequency transformer based isolated dc-dc Cuk converter is used to reduce size, weight and losses. The dc voltage of 360 V is fed to a single phase VSI with unipolar switching to achieve a 230 Vrms, 50 Hz ac. The main objectives of this investigation are on efficiency improvement, reduction in cost, weight and size of the system and to provide an uninterruptible power to remotely located consumers. The complete SPV system is designed and it is modeled in MATLAB/Simulink. The simulated results are presented to demonstrate its satisfactory performance for validating the proposed design and control algorithm.

Measuring exertion time, duty cycle and hand activity level for industrial tasks using computer vision.

PubMed

Akkas, Oguz; Lee, Cheng Hsien; Hu, Yu Hen; Harris Adamson, Carisa; Rempel, David; Radwin, Robert G

2017-12-01

Two computer vision algorithms were developed to automatically estimate exertion time, duty cycle (DC) and hand activity level (HAL) from videos of workers performing 50 industrial tasks. The average DC difference between manual frame-by-frame analysis and the computer vision DC was -5.8% for the Decision Tree (DT) algorithm, and 1.4% for the Feature Vector Training (FVT) algorithm. The average HAL difference was 0.5 for the DT algorithm and 0.3 for the FVT algorithm. A sensitivity analysis, conducted to examine the influence that deviations in DC have on HAL, found it remained unaffected when DC error was less than 5%. Thus, a DC error less than 10% will impact HAL less than 0.5 HAL, which is negligible. Automatic computer vision HAL estimates were therefore comparable to manual frame-by-frame estimates. Practitioner Summary: Computer vision was used to automatically estimate exertion time, duty cycle and hand activity level from videos of workers performing industrial tasks.

Adaptive Selective Harmonic Minimization Based on ANNs for Cascade Multilevel Inverters With Varying DC Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filho, Faete; Maia, Helder Z; Mateus, Tiago Henrique D

2013-01-01

A new approach for modulation of an 11-level cascade multilevel inverter using selective harmonic elimination is presented in this paper. The dc sources feeding the multilevel inverter are considered to be varying in time, and the switching angles are adapted to the dc source variation. This method uses genetic algorithms to obtain switching angles offline for different dc source values. Then, artificial neural networks are used to determine the switching angles that correspond to the real-time values of the dc sources for each phase. This implies that each one of the dc sources of this topology can have different valuesmore » at any time, but the output fundamental voltage will stay constant and the harmonic content will still meet the specifications. The modulating switching angles are updated at each cycle of the output fundamental voltage. This paper gives details on the method in addition to simulation and experimental results.« less

Analysis of gene expression during the transition to climacteric phase in carnation flowers (Dianthus caryophyllus L.).

PubMed

In, Byung-Chun; Binder, Brad M; Falbel, Tanya G; Patterson, Sara E

2013-11-01

It has been generally thought that in ethylene-sensitive plants such as carnations, senescence proceeds irreversibly once the tissues have entered the climacteric phase. While pre-climacteric petal tissues have a lower sensitivity to ethylene, these tissues are converted to the climacteric phase at a critical point during flower development. In this study, it is demonstrated that the senescence process initiated by exogenous ethylene is reversible in carnation petals. Petals treated with ethylene for 12h showed sustained inrolling and senescence, while petals treated with ethylene for 10h showed inrolling followed by recovery from inrolling. Reverse transcription-PCR analysis revealed differential expression of genes involved in ethylene biosynthesis and ethylene signalling between 10h and 12h ethylene treatment. Ethylene treatment at or beyond 12h (threshold time) decreased the mRNA levels of the receptor genes (DcETR1, DcERS1, and DcERS2) and DcCTR genes, and increased the ethylene biosynthesis genes DcACS1 and DcACO1. In contrast, ethylene treatment under the threshold time caused a transient decrease in the receptor genes and DcCTR genes, and a transient increase in DcACS1 and DcACO1. Sustained DcACS1 accumulation is correlated with decreases in DcCTR genes and increase in DcEIL3 and indicates that tissues have entered the climacteric phase and that senescence proceeds irreversibly. Inhibition of ACS (1-aminocyclopropane-1-carboxylic acid synthase) prior to 12h ethylene exposure was not able to prevent reduction in transcripts of DcCTR genes, yet suppressed transcript of DcACS1 and DcACO1. This leads to the recovery from inrolling of the petals, indicating that DcACS1 may act as a signalling molecule in senescence of flowers.

Analysis of gene expression during the transition to climacteric phase in carnation flowers (Dianthus caryophyllus L.)

PubMed Central

Patterson, Sara E.

2013-01-01

It has been generally thought that in ethylene-sensitive plants such as carnations, senescence proceeds irreversibly once the tissues have entered the climacteric phase. While pre-climacteric petal tissues have a lower sensitivity to ethylene, these tissues are converted to the climacteric phase at a critical point during flower development. In this study, it is demonstrated that the senescence process initiated by exogenous ethylene is reversible in carnation petals. Petals treated with ethylene for 12h showed sustained inrolling and senescence, while petals treated with ethylene for 10h showed inrolling followed by recovery from inrolling. Reverse transcription–PCR analysis revealed differential expression of genes involved in ethylene biosynthesis and ethylene signalling between 10h and 12h ethylene treatment. Ethylene treatment at or beyond 12h (threshold time) decreased the mRNA levels of the receptor genes (DcETR1, DcERS1, and DcERS2) and DcCTR genes, and increased the ethylene biosynthesis genes DcACS1 and DcACO1. In contrast, ethylene treatment under the threshold time caused a transient decrease in the receptor genes and DcCTR genes, and a transient increase in DcACS1 and DcACO1. Sustained DcACS1 accumulation is correlated with decreases in DcCTR genes and increase in DcEIL3 and indicates that tissues have entered the climacteric phase and that senescence proceeds irreversibly. Inhibition of ACS (1-aminocyclopropane-1-carboxylic acid synthase) prior to 12h ethylene exposure was not able to prevent reduction in transcripts of DcCTR genes, yet suppressed transcript of DcACS1 and DcACO1. This leads to the recovery from inrolling of the petals, indicating that DcACS1 may act as a signalling molecule in senescence of flowers. PMID:24078672

Analysis and Countermeasure Study on DC Bias of Main Transformer in a City

NASA Astrophysics Data System (ADS)

Wang, PengChao; Wang, Hongtao; Song, Xinpu; Gu, Jun; Liu, yong; Wu, weili

2017-07-01

According to the December 2015 Guohua Beijing thermal power transformer DC magnetic bias phenomenon, the monitoring data of 24 hours of direct current is analyzed. We find that the maximum DC current is up to 25 and is about 30s for the trend cycle, on this basis, then, of the geomagnetic storm HVDC and subway operation causes comparison of the mechanism, and make a comprehensive analysis of the thermal power plant’s geographical location, surrounding environment and electrical contact etc.. The results show that the main reason for the DC bias of Guohua thermal power transformer is the operation of the subway, and the change of the DC bias current is periodic. Finally, of Guohua thermal power transformer DC magnetic bias control method is studied, the simulation results show that the method of using neutral point with small resistance or capacitance can effectively inhibit the main transformer neutral point current.

Single Stage Rocket Technology's real time data system

NASA Technical Reports Server (NTRS)

Voglewede, Steven D.

1994-01-01

The Single Stage Rocket Technology (SSRT) Delta Clipper Experimental (DC-X) Program is a United States Air Force Ballistic Missile Defense Organization (BMDO) rapid prototyping initiative that is currently demonstrating technology readiness for reusable suborbital rockets. The McDonnell Douglas DC-X rocket performed technology demonstrations at the U.S. Army White Sands Missile Range in New Mexico from April-October in 1993. The DC-X Flight Operations Control Center (FOCC) contains the ground control system that is used to monitor and control the DC-X vehicle and its Ground Support Systems (GSS). The FOCC is operated by a flight crew of three operators. Two operators manage the DC-X Flight Systems and one operator is the Ground Systems Manager. A group from McDonnell Douglas Aerospace at KSC developed the DC-X ground control system for the FOCC. This system is known as the Real Time Data System (RTDS). The RTDS is a distributed real time control and monitoring system that utilizes the latest available commercial off-the-shelf computer technology. The RTDS contains front end interfaces for the DC-X RF uplink/downlink and fiber optic interfaces to the GSS equipment. This paper describes the RTDS architecture and FOCC layout. The DC-X applications and ground operations are covered.

Light-weight DC to very high voltage DC converter

DOEpatents

Druce, R.L.; Kirbie, H.C.; Newton, M.A.

1998-06-30

A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

RNA interference of two glutathione S-transferase genes, Diaphorina citri DcGSTe2 and DcGSTd1, increases the susceptibility of Asian citrus psyllid (Hemiptera: Liviidae) to the pesticides fenpropathrin and thiamethoxam.

PubMed

Yu, Xiudao; Killiny, Nabil

2018-03-01

The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important agricultural pest of citrus globally. Foliar application of chemical insecticides is the most widely used option for reducing D. citri populations. Knockdown of glutathione S-transferase (GST) in several insect species leads to increased susceptibility to insecticides; however, information about the detoxifying role of GST genes in D. citri is unavailable. Via a sequence homology search, we isolated and characterized three DcGST genes (DcGSTd1, DcGSTe1 and DcGSTe2) from D. citri. Phylogenetic analysis grouped DcGSTd1 into the delta class of GST genes, whereas DcGSTe1 and DcGSTe2 were clustered in the epsilon clade. Gene expression analysis revealed that chlorpyrifos treatment increased the mRNA levels of DcGSTe1 and fenpropathrin enhanced the expression level of DcGSTd1, while DcGSTe2 was significantly up-regulated after exposure to thiamethoxam at a dose of 30% lethal concentration (LC30). RNA interference (RNAi) of DcGSTe2 and DcGSTd1 followed by an insecticide bioassay increased the mortalities of thiamethoxam-treated psyllids by 23.0% and fenpropathrin-treated psyllids by 15.0%. In contrast, knockdown of DcGSTe1 did not significantly increase the susceptibility of D. citri to any of these three insecticides. Further, feeding with double-stranded RNA (dsDcGSTe2-d1) interfusion co-silenced DcGSTe2 and DcGSTd1 expression in D. citri, and led to an increase of susceptibility to both fenpropathrin and thiamethoxam. The findings suggest that DcGSTe2 and DcGSTd1 play unique roles in detoxification of the pesticides thiamethoxam and fenpropathrin. In addition, co-silencing by creating a well-designed dsRNA interfusion against multiple genes was a good RNAi strategy in D. citri. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Pulsed helium ionization detection system

DOEpatents

Ramsey, R.S.; Todd, R.A.

1985-04-09

A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

Pulsed helium ionization detection system

DOEpatents

Ramsey, Roswitha S.; Todd, Richard A.

1987-01-01

A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

Digital phase-locked loop speed control for a brushless dc motor

NASA Astrophysics Data System (ADS)

Wise, M. G.

1985-06-01

Speed control of d.c. motors by phase-locked loops (PLL) is becoming increasingly popular. Primary interest has been in employing PLL for constant speed control. This thesis investigates the theory and techniques of digital PLL to speed control of a brushless d.c. motor with a variable speed of operation. Addition of logic controlled count enable/disable to a synchronous up/down counter, used as a phase-frequency detector, is shown to improve the performance of previously proposed PLL control schemes.

49 CFR 219.211 - Analysis and follow-up.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Program Manager, Office of Safety, FRA, 1200 New Jersey Avenue, SE., Washington, DC 20590 within 45 days... Safety Board. (c) With respect to a surviving employee, a test reported as positive for alcohol or a... of each review to the Associate Administrator for Safety, FRA, Washington, DC 20590. Such report must...

High-pressure microhydraulic actuator

DOEpatents

Mosier, Bruce P [San Francisco, CA; Crocker, Robert W [Fremont, CA; Patel, Kamlesh D [Dublin, CA

2008-06-10

Electrokinetic ("EK") pumps convert electric to mechanical work when an electric field exerts a body force on ions in the Debye layer of a fluid in a packed bed, which then viscously drags the fluid. Porous silica and polymer monoliths (2.5-mm O.D., and 6-mm to 10-mm length) having a narrow pore size distribution have been developed that are capable of large pressure gradients (250-500 psi/mm) when large electric fields (1000-1500 V/cm) are applied. Flowrates up to 200 .mu.L/min and delivery pressures up to 1200 psi have been demonstrated. Forces up to 5 lb-force at 0.5 mm/s (12 mW) have been demonstrated with a battery-powered DC-DC converter. Hydraulic power of 17 mW (900 psi@ 180 uL/min) has been demonstrated with wall-powered high voltage supplies. The force and stroke delivered by an actuator utilizing an EK pump are shown to exceed the output of solenoids, stepper motors, and DC motors of similar size, despite the low thermodynamic efficiency.

Improved DC and RF performance of InAlAs/InGaAs InP based HEMTs using ultra-thin 15 nm ALD-Al2O3 surface passivation

NASA Astrophysics Data System (ADS)

Asif, Muhammad; Chen, Chen; Peng, Ding; Xi, Wang; Zhi, Jin

2018-04-01

Owing to the great influence of surface passivation on DC and RF performance of InP-based HEMTs, the DC and RF performance of InAlAs/InGaAs InP HEMTs were studied before and after passivation, using an ultra-thin 15 nm atomic layer deposition Al2O3 layer. Increase in Cgs and Cgd was significantly limited by scaling the thickness of the Al2O3 layer. For verification, an analytical small-signal equivalent circuit model was developed. A significant increase in maximum transconductance (gm) up to 1150 mS/mm, drain current (IDS) up to 820 mA/mm and fmax up to 369.7 GHz was observed, after passivation. Good agreement was obtained between the measured and the simulated results. This shows that the RF performance of InP-based HEMTs can be improved by using an ultra-thin ALD-Al2O3 surface passivation.

Dynamics of runaway tails with time-dependent sub-Dreicer dc fields in magnetized plasmas

NASA Technical Reports Server (NTRS)

Moghaddam-Taaheri, E.; Vlahos, L.

1987-01-01

The evolution of runaway tails driven by sub-Dreicer time-dependent dc fields in a magnetized plasma are studied numerically using a quasi-linear code based on the Ritz-Galerkin method and finite elements. It is found that the runaway tail maintained a negative slope during the dc field increase. Depending on the values of the dc electric field at t = 0 and the electron gyrofrequency to the plasma frequency ratio the runaway tail became unstable to the anomalous Doppler resonance or remained stable before the saturation of the dc field at some maximum value. The systems that remained stable during this stage became unstable to the anomalous Doppler or the Cerenkov resonances when the dc field was kept at the saturation level or decreased. Once the instability is triggered, the runaway tail is isotropized.

Technical advance: live-imaging analysis of human dendritic cell migrating behavior under the influence of immune-stimulating reagents in an organotypic model of lung.

PubMed

Nguyen Hoang, Anh Thu; Chen, Puran; Björnfot, Sofia; Högstrand, Kari; Lock, John G; Grandien, Alf; Coles, Mark; Svensson, Mattias

2014-09-01

This manuscript describes technical advances allowing manipulation and quantitative analyses of human DC migratory behavior in lung epithelial tissue. DCs are hematopoietic cells essential for the maintenance of tissue homeostasis and the induction of tissue-specific immune responses. Important functions include cytokine production and migration in response to infection for the induction of proper immune responses. To design appropriate strategies to exploit human DC functional properties in lung tissue for the purpose of clinical evaluation, e.g., candidate vaccination and immunotherapy strategies, we have developed a live-imaging assay based on our previously described organotypic model of the human lung. This assay allows provocations and subsequent quantitative investigations of DC functional properties under conditions mimicking morphological and functional features of the in vivo parental tissue. We present protocols to set up and prepare tissue models for 4D (x, y, z, time) fluorescence-imaging analysis that allow spatial and temporal studies of human DCs in live epithelial tissue, followed by flow cytometry analysis of DCs retrieved from digested tissue models. This model system can be useful for elucidating incompletely defined pathways controlling DC functional responses to infection and inflammation in lung epithelial tissue, as well as the efficacy of locally administered candidate interventions. © 2014 Society for Leukocyte Biology.

Modelling and simulation of current fed dc to dc converter for PHEV applications using renewable source

NASA Astrophysics Data System (ADS)

Milind Metha, Manish; Tutki, Sanjay; Rajan, Aju; Elangovan, D.; Arunkumar, G.

2017-11-01

With the current rate of depletion of the fossil fuel the need to switch on to the renewable energy sources is the need of the hour. Thus the need for new and efficient converters arises so as to replace the existing less efficient diesel and petroleum IC engines with renewable energy sources. The PHEVs, which have been launched in the market, and Upcoming PHEVs have converters around 380V to 400V generated with a power range between 2KW to 2.8KW. The fundamental target of this paper is to plan a productive converter keeping in mind cost and size restriction. In this paper, a two-stage dc-dc converter is proposed. The proposed converter is utilized to venture up a voltage from 24V (photovoltaic source) to a yield voltage of 400V to take care of a power demand of 2.4kW for a plug-in hybrid electric vehicle (PHEV) application considering the real time scenario of PHEV. This paper talks about in detail why the current fed converter is utilized alongside a voltage doubler thus minimizing the transformer turns thereby reducing the overall size of the final product. Simulation results along with calculation for the duty cycle of the firing sequence for different value of transformer turns are presented for a prototype unit.

The use of Collagenase Clostridium Histolyticum in the management of Dupuytren's contracture-outcomes of a pilot study in a District General Hospital setting.

PubMed

Murphy, Lynn E; Murphy, Karen M; Kilpatrick, Shauneen M; Thompson, Neville W

2017-05-01

Collagenase Clostridium Histolyticum (CCH) is a recognised treatment option for adult patients presenting with Dupuytren's contracture (DC). Twenty male patients with established DC were treated using CCH. The average metacarpophalangeal (MCP) joint and proximal interphalangeal joint (PIP) contractures pre-treatment were 52 0 (range, 0 - 75 0 ) and 35 0 (range, 0 - 84 0 ) respectively. The average DASH score pre-treatment was 24.2 points (range, 0 - 68.2 points). Patients were reviewed at lmonth, 3months and at an average of 23 months (17 to 27 months). MCP joint contractures significantly improved compared to pre-treatment and the improvement was maintained at latest follow up. PIP joint contractures did significantly improve but to a lesser degree and there was no significant improvement compared to pre-treatment beyond 3months. A trend for MCP and PIP joint contracture recurrence was observed at latest follow up but did not reach statistical significance. DASH scores significantly improved from pre-treatment and the improvement was maintained at latest follow up. At 3months, the average patient satisfaction score was 9.5 (range, 6 - 10), which decreased to 8.6 (range, 6 - 10) at latest follow up. We estimated a potential cost saving of approximately £70,000 by treating 20 patients using CCH compared to inpatient operative fasciectomy. CCH is a useful option in the management of DC in appropriately selected patients. Cost-effectiveness in the treatment of DC should be carefully considered.

Bidirectional DC/DC Converter

NASA Astrophysics Data System (ADS)

Pedersen, F.

2008-09-01

The presented bidirectional DC/DC converter design concept is a further development of an already existing converter used for low battery voltage operation.For low battery voltage operation a high efficient low parts count DC/DC converter was developed, and used in a satellite for the battery charge and battery discharge function.The converter consists in a bidirectional, non regulating DC/DC converter connected to a discharge regulating Buck converter and a charge regulating Buck converter.The Bidirectional non regulating DC/DC converter performs with relatively high efficiency even at relatively high currents, which here means up to 35Amps.This performance was obtained through the use of power MOSFET's with on- resistances of only a few mille Ohms connected to a special transformer allowing paralleling several transistor stages on the low voltage side of the transformer. The design is patent protected. Synchronous rectification leads to high efficiency at the low battery voltages considered, which was in the range 2,7- 4,3 Volt DC.The converter performs with low switching losses as zero voltage zero current switching is implemented in all switching positions of the converter.Now, the drive power needed, to switch a relatively large number of low Ohm , hence high drive capacitance, power MOSFET's using conventional drive techniques would limit the overall conversion efficiency.Therefore a resonant drive consuming considerable less power than a conventional drive circuit was implemented in the converter.To the originally built and patent protected bidirectional non regulating DC/DC converter, is added the functionality of regulation.Hereby the need for additional converter stages in form of a Charge Buck regulator and a Discharge Buck regulator is eliminated.The bidirectional DC/DC converter can be used in connection with batteries, motors, etc, where the bidirectional feature, simple design and high performance may be useful.

Haemophilus ducreyi Partially Activates Human Myeloid Dendritic Cells▿

PubMed Central

Banks, Keith E.; Humphreys, Tricia L.; Li, Wei; Katz, Barry P.; Wilkes, David S.; Spinola, Stanley M.

2007-01-01

Dendritic cells (DC) orchestrate innate and adaptive immune responses to bacteria. How Haemophilus ducreyi, which causes genital ulcers and regional lymphadenitis, interacts with DC is unknown. H. ducreyi evades uptake by polymorphonuclear leukocyte and macrophage-like cell lines by secreting LspA1 and LspA2. Many H. ducreyi strains express cytolethal distending toxin (CDT), and recombinant CDT causes apoptosis of DC in vitro. Here, we examined interactions between DC and H. ducreyi 35000HP, which produces LspA1, LspA2, and CDT. In human volunteers infected with 35000HP, the ratio of myeloid DC to plasmacytoid DC was 2.8:1 in lesions, compared to a ratio of 1:1 in peripheral blood. Using myeloid DC derived from monocytes as surrogates for lesional DC, we found that DC infected with 35000HP remained as viable as uninfected DC for up to 48 h. Gentamicin protection and confocal microscopy assays demonstrated that DC ingested and killed 35000HP, but killing was incomplete at 48 h. The expression of LspA1 and LspA2 did not inhibit the uptake of H. ducreyi, despite inactivating Src kinases. Infection of DC with live 35000HP caused less cell surface marker activation than infection with heat-killed 35000HP and lipopolysaccharide (LPS) and inhibited maturation by LPS. However, infection of DC with live bacteria caused the secretion of significantly higher levels of interleukin-6 and tumor necrosis factor alpha than infection with heat-killed bacteria and LPS. The survival of H. ducreyi in DC may provide a mechanism by which the organism traffics to lymph nodes. Partial activation of DC may abrogate the establishment of a full Th1 response and an environment that promotes phagocytosis. PMID:17923525

The Clinical Value of Deflation Cough in Chronic Coughers With Reflux Symptoms.

PubMed

Lavorini, Federico; Chellini, Elisa; Bigazzi, Francesca; Surrenti, Elisabetta; Fontana, Giovanni A

2016-06-01

Patients with deflation cough (DC), the cough-like expulsive effort(s) evoked by maximal lung emptying during a slow vital capacity maneuver, also present symptoms of gastroesophageal reflux. DC can be inhibited by prior intake of antacids. We wished to assess DC prevalence and association between DC and chemical characteristics of refluxate in patients with gastroesophageal reflux symptoms. A total of 157 consecutive outpatients underwent DC assessment and 24-h multichannel intraluminal impedance pH (MII-pH) monitoring; 93/157 also had chronic cough. Patients performed two to four slow vital capacity maneuvers and DC was detected aurally. Subsequently, they underwent 24-h MII-pH monitoring, the outcomes of which were defined as abnormal when acid or non-acid reflux events were > 73. DC occurred in 46/157 patients, 18 of whom had abnormal MII-pH outcomes; 28 of the remaining 111 patients without DC also had abnormal MII-pH findings. Thus, in the patients as a group, there was no association between DC and MII-pH outcomes. DC occurred in 40/93 of the chronic coughers; 15 of whom had acid reflux. All but 2 of the 53 patients without DC had normal MII-pH outcomes (P < .001), and the negative predictive value of DC for excluding acid reflux was 96.2%. At follow-up, 65% of coughers showed significant improvement after treatment. The overall prevalence of DC was 29%, increasing to 43% in chronic coughers in whom the absence of DC virtually excludes acid reflux. Therefore, DC assessment may represent a useful screening test for excluding acid reflux in chronic coughers with reflux symptoms. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Early Oscillation Detection Technique for Hybrid DC/DC Converters

NASA Technical Reports Server (NTRS)

Wang, Bright L.

2011-01-01

Oscillation or instability is a situation that must be avoided for reliable hybrid DC/DC converters. A real-time electronics measurement technique was developed to detect catastrophic oscillations at early stages for hybrid DC/DC converters. It is capable of identifying low-level oscillation and determining the degree of the oscillation at a unique frequency for every individual model of the converters without disturbing their normal operations. This technique is specially developed for space-used hybrid DC/DC converters, but it is also suitable for most of commercial and military switching-mode power supplies. This is a weak-electronic-signal detection technique to detect hybrid DC/DC converter oscillation presented as a specific noise signal at power input pins. It is based on principles of feedback control loop oscillation and RF signal modulations, and is realized by using signal power spectral analysis. On the power spectrum, a channel power amplitude at characteristic frequency (CPcf) and a channel power amplitude at switching frequency (CPsw) are chosen as oscillation level indicators. If the converter is stable, the CPcf is a very small pulse and the CPsw is a larger, clear, single pulse. At early stage of oscillation, the CPcf increases to a certain level and the CPsw shows a small pair of sideband pulses around it. If the converter oscillates, the CPcf reaches to a higher level and the CPsw shows more high-level sideband pulses. A comprehensive stability index (CSI) is adopted as a quantitative measure to accurately assign a degree of stability to a specific DC/DC converter. The CSI is a ratio of normal and abnormal power spectral density, and can be calculated using specified and measured CPcf and CPsw data. The novel and unique feature of this technique is the use of power channel amplitudes at characteristic frequency and switching frequency to evaluate stability and identify oscillations at an early stage without interfering with a DC/DC converter s normal operation. This technique eliminates the probing problem of a gain/phase margin method by connecting the power input to a spectral analyzer. Therefore, it is able to evaluate stability for all kinds of hybrid DC/DC converters with or without remote sense pins, and is suitable for real-time and in-circuit testing. This frequency-domain technique is more sensitive to detect oscillation at early stage than the time-domain method using an oscilloscope.

Distributed control system for parallel-connected DC boost converters

DOEpatents

Goldsmith, Steven

2017-08-15

The disclosed invention is a distributed control system for operating a DC bus fed by disparate DC power sources that service a known or unknown load. The voltage sources vary in v-i characteristics and have time-varying, maximum supply capacities. Each source is connected to the bus via a boost converter, which may have different dynamic characteristics and power transfer capacities, but are controlled through PWM. The invention tracks the time-varying power sources and apportions their power contribution while maintaining the DC bus voltage within the specifications. A central digital controller solves the steady-state system for the optimal duty cycle settings that achieve a desired power supply apportionment scheme for a known or predictable DC load. A distributed networked control system is derived from the central system that utilizes communications among controllers to compute a shared estimate of the unknown time-varying load through shared bus current measurements and bus voltage measurements.

Large-Signal Lyapunov-Based Stability Analysis of DC/AC Inverters and Inverter-Based Microgrids

NASA Astrophysics Data System (ADS)

Kabalan, Mahmoud

Microgrid stability studies have been largely based on small-signal linearization techniques. However, the validity and magnitude of the linearization domain is limited to small perturbations. Thus, there is a need to examine microgrids with large-signal nonlinear techniques to fully understand and examine their stability. Large-signal stability analysis can be accomplished by Lyapunov-based mathematical methods. These Lyapunov methods estimate the domain of asymptotic stability of the studied system. A survey of Lyapunov-based large-signal stability studies showed that few large-signal studies have been completed on either individual systems (dc/ac inverters, dc/dc rectifiers, etc.) or microgrids. The research presented in this thesis addresses the large-signal stability of droop-controlled dc/ac inverters and inverter-based microgrids. Dc/ac power electronic inverters allow microgrids to be technically feasible. Thus, as a prelude to examining the stability of microgrids, the research presented in Chapter 3 analyzes the stability of inverters. First, the 13 th order large-signal nonlinear model of a droop-controlled dc/ac inverter connected to an infinite bus is presented. The singular perturbation method is used to decompose the nonlinear model into 11th, 9th, 7th, 5th, 3rd and 1st order models. Each model ignores certain control or structural components of the full order model. The aim of the study is to understand the accuracy and validity of the reduced order models in replicating the performance of the full order nonlinear model. The performance of each model is studied in three different areas: time domain simulations, Lyapunov's indirect method and domain of attraction estimation. The work aims to present the best model to use in each of the three domains of study. Results show that certain reduced order models are capable of accurately reproducing the performance of the full order model while others can be used to gain insights into those three areas of study. This will enable future studies to save computational effort and produce the most accurate results according to the needs of the study being performed. Moreover, the effect of grid (line) impedance on the accuracy of droop control is explored using the 5th order model. Simulation results show that traditional droop control is valid up to R/X line impedance value of 2. Furthermore, the 3rd order nonlinear model improves the currently available inverter-infinite bus models by accounting for grid impedance, active power-frequency droop and reactive power-voltage droop. Results show the 3rd order model's ability to account for voltage and reactive power changes during a transient event. Finally, the large-signal Lyapunov-based stability analysis is completed for a 3 bus microgrid system (made up of 2 inverters and 1 linear load). The thesis provides a systematic state space large-signal nonlinear mathematical modeling method of inverter-based microgrids. The inverters include the dc-side dynamics associated with dc sources. The mathematical model is then used to estimate the domain of asymptotic stability of the 3 bus microgrid. The three bus microgrid system was used as a case study to highlight the design and optimization capability of a large-signal-based approach. The study explores the effect of system component sizing, load transient and generation variations on the asymptotic stability of the microgrid. Essentially, this advancement gives microgrid designers and engineers the ability to manipulate the domain of asymptotic stability depending on performance requirements. Especially important, this research was able to couple the domain of asymptotic stability of the ac microgrid with that of the dc side voltage source. Time domain simulations were used to demonstrate the mathematical nonlinear analysis results.

DcR3 binds to ovarian cancer via heparan sulfate proteoglycans and modulates tumor cells response to platinum with corresponding alteration in the expression of BRCA1

PubMed Central

2012-01-01

Background Overcoming platinum resistance is a major obstacle in the treatment of Epithelial Ovarian Cancer (EOC). In our previous work Decoy Receptor 3 (DcR3) was found to be related to platinum resistance. The major objective of this work was to define the cellular interaction of DcR3 with EOC and to explore its effects on platinum responsiveness. Methods We studied cell lines and primary cultures for the expression of and the cells ability to bind DcR3. Cells were cultured with DcR3 and then exposed to platinum. Cell viability was determined by MTT assay. Finally, the cells molecular response to DcR3 was studied using real time RT-PCR based differential expression arrays, standard RT-PCR, and Western blot. Results High DcR3 in the peritoneal cavity of women with EOC is associated with significantly shorter time to first recurrence after platinum based therapy (p = 0.02). None-malignant cells contribute DcR3 in the peritoneal cavity. The cell lines studied do not secrete DcR3; however they all bind exogenous DcR3 to their surface implying that they can be effected by DcR3 from other sources. DcR3s protein binding partners are minimally expressed or negative, however, all cells expressed the DcR3 binding Heparan Sulfate Proteoglycans (HSPGs) Syndecans-2, and CD44v3. DcR3 binding was inhibited by heparin and heparinase. After DcR3 exposure both SKOV-3 and OVCAR-3 became more resistant to platinum with 15% more cells surviving at high doses. On the contrary CaOV3 became more sensitive to platinum with 20–25% more cell death. PCR array analysis showed increase expression of BRCA1 mRNA in SKOV-3 and OVCAR-3 and decreased BRCA1 expression in CaOV-3 after exposure to DcR3. This was confirmed by gene specific real time PCR and Western blot analysis. Conclusions Non-malignant cells contribute to the high levels of DcR3 in ovarian cancer. DcR3 binds readily to EOC cells via HSPGs and alter their responsiveness to platinum chemotherapy. The paradoxical responses seen were related to the expression pattern of HSPGs available on the cells surface to interact with. Although the mechanism behind this is not completely known alterations in DNA repair pathways including the expression of BRCA1 appear to be involved. PMID:22583667

The Clinical Significance of DC-SIGN and DC-SIGNR, which Are Novel Markers Expressed in Human Colon Cancer

PubMed Central

Chen, Kai; Chen, Zhe; Sun, Zhigang; Zhang, Zhuqing; Ding, Dongbing; Ren, Shuangyi; Zuo, Yunfei

2014-01-01

Background Colon cancer has always been diagnosed at a late stage, which is associated with poor prognosis. The currently used serum tumor markers CEA and CA19-9 display low sensitivity and specificity and may not have diagnostic value in early stage colon cancer. Thus, there is an urgent need to identify novel serum biomarkers for use in the early detection of colon cancer. Methods In this study, the expression of DC-SIGN and DC-SIGNR in serum was detected by enzyme-linked immunosorbent assay (ELISA). DC-SIGN and DC-SIGNR expression was detected in cancer tissues by immunohistochemistry (IHC). Results The level of sDC-SIGN was lower in patients than in the healthy controls, while the level of sDC-SIGNR in patients was higher than in the healthy controls. Both sDC-SIGN and sDC-SIGNR had diagnostic significances for cancer patients, and the combined diagnosis of these two markers was higher than both of them alone. Furthermore, there were significant differences between both sDC-SIGN and sDC-SIGNR in stage I/II patients and the healthy controls. Moreover, high sDC-SIGN level was accompanied with the long survival time. Additionally, DC-SIGNR was negative in the cancer foci and matched normal colon tissues but was weakly positive between the cancer foci. DC-SIGN staining was faint in matched normal colon tissues, strong in the tumor stroma and the invasive margin of colon cancer tissues, and negatively correlated with the sDC-SIGN level in serum from the same patient. Interestingly, the percent survival of patients with a DC-SIGN mean density of>0.001219 (the upper 95% confidence interval of matched normal colon tissues) was higher than for all other patients. Conclusion DC-SIGN and DC-SIGNR are blood-based molecular markers that can potentially be used for the diagnosis of early stage patients. Moreover, expression of DC-SIGN in serum and cancer tissues may affect the survival time for colon cancer patients. PMID:25504222

76 FR 77890 - Union Pacific Railroad Company-Petition for Declaratory Order

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-14

... Avenue NW., Washington, DC 20004-2401, [email protected] (representing UP); (2) David L. Coleman, Law... negligence or fault of UP. UP's petition raises questions about what constitutes a reasonable request for...

Research on resistance characteristics of YBCO tape under short-time DC large current impact

NASA Astrophysics Data System (ADS)

Zhang, Zhifeng; Yang, Jiabin; Qiu, Qingquan; Zhang, Guomin; Lin, Liangzhen

2017-06-01

Research of the resistance characteristics of YBCO tape under short-time DC large current impact is the foundation of the developing DC superconducting fault current limiter (SFCL) for voltage source converter-based high voltage direct current system (VSC-HVDC), which is one of the valid approaches to solve the problems of renewable energy integration. SFCL can limit DC short-circuit and enhance the interrupting capabilities of DC circuit breakers. In this paper, under short-time DC large current impacts, the resistance features of naked tape of YBCO tape are studied to find the resistance - temperature change rule and the maximum impact current. The influence of insulation for the resistance - temperature characteristics of YBCO tape is studied by comparison tests with naked tape and insulating tape in 77 K. The influence of operating temperature on the tape is also studied under subcooled liquid nitrogen condition. For the current impact security of YBCO tape, the critical current degradation and top temperature are analyzed and worked as judgment standards. The testing results is helpful for in developing SFCL in VSC-HVDC.

On the nonlinear variation of dc conductivity with dielectric relaxation time

NASA Astrophysics Data System (ADS)

Johari, G. P.; Andersson, Ove

2006-09-01

The long-known observations that dc conductivity σdc of an ultraviscous liquid varies nonlinearly with the dielectric relaxation time τ, and the slope of the logσdc against logτ plot deviates from -1 are currently seen as two of the violations of the Debye-Stokes-Einstein equation. Here we provide a formalism using a zeroth order Bjerrum description for ion association to show that in addition to its variation with temperature T and pressure P, impurity ion population varies with a liquid's equilibrium dielectric permittivity. Inclusion of this electrostatic effect modifies the Debye-Stokes-Einstein equation to log(σdcτ )=constant+logα, where α is the T and P-dependent degree of ionic dissociation of an electrolytic impurity. Variation of a liquid's shear modulus with T and P would add to the nonlinearity of σdc-τ relation, as would a nonequivalence of the shear and dielectric relaxation times, proton transfer along the hydrogen bonds, or occurrence of another chemical process. This is illustrated by using the data for ultraviscous acetaminophen-aspirin liquid.

Regulated dc-to-dc converter for voltage step-up or step-down with input-output isolation

NASA Technical Reports Server (NTRS)

Feng, S. Y.; Wilson, T. G. (Inventor)

1973-01-01

A closed loop regulated dc-to-dc converter employing an unregulated two winding inductive energy storage converter is provided by using a magnetically coupled multivibrator acting as duty cycle generator to drive the converter. The multivibrator is comprised of two transistor switches and a saturable transformer. The output of the converter is compared with a reference in a comparator which transmits a binary zero until the output exceeds the reference. When the output exceeds the reference, the binary output of the comparator drives transistor switches to turn the multivibrator off. The multivibrator is unbalanced so that a predetermined transistor will always turn on first when the binary feedback signal becomes zero.

High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, D.W.; Lange, A.C.

1995-05-23

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1995-01-01

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

Parks, Trees, and Environmental Justice: Field Notes from Washington, DC

ERIC Educational Resources Information Center

Buckley, Geoffrey L.; Whitmer, Ali; Grove, J. Morgan

2013-01-01

Students enrolled in a graduate seminar benefited in multiple ways from an intensive 3-day field trip to Washington, DC. Constructed around the theme of environmental justice, the trip gave students a chance to learn about street tree distribution, park quality, and racial segregation "up close." Working with personnel from the United…

A low-power high-sensitivity analog front-end for PPG sensor.

PubMed

Binghui Lin; Atef, Mohamed; Guoxing Wang

2017-07-01

This paper presents a low-power analog front-end (AFE) photoplethysmography (PPG) sensor fabricated in 0.35 μm CMOS process. The AFE amplifies the weak photocurrent from the photodiode (PD) and converts it to a strong voltage at the output. In order to decrease the power consumption, the circuits are designed in subthreshold region; so the total biasing current of the AFE is 10 μ A. Since the large input DC photocurrent is a big issue for the PPG sensing circuit, we apply a DC photocurrent rejection technique by adding a DC current-cancellation loop to reject the large DC photocurrent up to 10 μA. In addition, a pseudo resistor is used to reduce the high-pass corner frequency below 0.5 Hz and Gm-C filter is adapted to reject the out-of-band noise higher than 16 Hz. For the whole sensor, the amplifier chain can achieve a total gain of 140 dBμ and an input integrated noise current of 68.87 pA rms up to 16 Hz.

Two new families of high-gain dc-dc power electronic converters for dc-microgrids

NASA Astrophysics Data System (ADS)

Prabhala, Venkata Anand Kishore

Distributing the electric power in dc form is an appealing solution in many applications such as telecommunications, data centers, commercial buildings, and microgrids. A high gain dc-dc power electronic converter can be used to individually link low-voltage elements such as solar panels, fuel cells, and batteries to the dc voltage bus which is usually 400 volts. This way, it is not required to put such elements in a series string to build up their voltages. Consequently, each element can function at it optimal operating point regardless of the other elements in the system. In this dissertation, first a comparative study of dc microgrid architectures and their advantages over their ac counterparts is presented. Voltage level selection of dc distribution systems is discussed from the cost, reliability, efficiency, and safety standpoints. Next, a new family of non-isolated high-voltage-gain dc-dc power electronic converters with unidirectional power flow is introduced. This family of converters benefits from a low voltage stress across its switches. The proposed topologies are versatile as they can be utilized as single-input or double-input power converters. In either case, they draw continuous currents from their sources. Lastly, a bidirectional high-voltage-gain dc-dc power electronic converter is proposed. This converter is comprised of a bidirectional boost converter which feeds a switched-capacitor architecture. The switched-capacitor stage suggested here has several advantages over the existing approaches. For example, it benefits from a higher voltage gain while it uses less number of capacitors. The proposed converters are highly efficient and modular. The operating modes, dc voltage gain, and design procedure for each converter are discussed in details. Hardware prototypes have been developed in the lab. The results obtained from the hardware agree with those of the simulation models.

A Study of 4-level DC-DC Boost Inverter with Passive Component Reduction Consideration

NASA Astrophysics Data System (ADS)

Kasiran, A. N.; Ponniran, A.; Harimon, M. A.; Hamzah, H. H.

2018-04-01

This study is to analyze design principles of boost inductor and capacitor used in the 4-level DC-DC boost converter to realize size reduction of passive component referring to their attributes. The important feature of this circuit is that most of the boost-up energy is transferred from the capacitor-clamped to the output side which the small inductance can be used at the input side. The inductance of the boost inductor is designed by referring the inductor current ripple. On the other hand, the capacitance of the capacitor-clamped is designed by considering voltage stress on semiconductor devices and also the used switching frequency. Besides that, according to the design specifications, the required inductance in 4-level DC-DC boost converter is decreased compared to a conventional conventional DC-DC boost converter. Meanwhile, voltage stress on semiconductor device is depending on the maximum voltage ripple of the capacitor-clamped. A 50 W 4-level DC-DC boost converter prototype has been constructed. The results show that the inductor current ripple was 1.15 A when the inductors, 1 mH and 0.11 mH were used in the conventional and 4-level DC-DC boost converters, respectively. Thus, based on the experimental results, it shows that the reduction of passive components by referring to their attributes in 4-level DC-DC boost converter is achieved. Moreover, the decreasing of voltage stress on the semiconductor devices is an advantage for the selection of low ON-resistance of the devices which will contribute to the reduction of the semiconductor conduction loss. The integration result of boost converter and H-bridge inverter is also shown.

Rejuvenation of the Innocent Bystander: Testing Spin-Up in a Dwarf Carbon Star Sample

NASA Astrophysics Data System (ADS)

Green, Paul

2014-09-01

Carbon stars (C>O) were long assumed to all be giants, because only AGB stars dredge up significant carbon into their atmospheres. We now know that dwarf carbon (dC) stars are actually far more common than C giants. These dC stars are hypothesized to have accreted C-rich envelope material from an AGB companion, in systems that have likely undergone a planetary nebula phase, eventually yielding a white dwarf and a dC star that has gained both significant mass and angular momentum. To test whether the X-ray emission strength and spectral properties are consistent with a rejuvenated dynamo, we propose a Chandra pilot study of dCs selected from the SDSS; some have hot white dwarf companions (indicating more recent mass transfer), and all show Balmer emission lines (a sign of activity).

Cardiomyopathy in Patients With Hereditary Bullous Epidermolysis.

PubMed

Batalla, A; Vicente, A; Bartrons, J; Prada, F; Fortuny, C; González-Enseñat, M A

In recent decades, an association has been reported between epidermolysis bullosa (EB) and dilated cardiomyopathy (DC). DC is typically in an advanced phase when detected, leading to a poorer prognosis. Our objective was to determine the prevalence of DC in patients with EB seen in Hospital San Joan de Déu in Barcelona, Spain, between May 1986 and April 2015. This was a descriptive, cross-sectional chart-review study in which we recorded the type and main subtypes of EB and the presence or absence of DC. Fifty-seven patients with EB were found, 19 with EB simplex, 10 with junctional EB, 27 with dystrophic EB (14 dominant dystrophic and 13 recessive dystrophic), and just 1 with Kindler syndrome. DC was detected in only 2 patients with recessive dystrophic EB. Twenty-three patients had presented factors that could have had a causal relationship with the potential onset of DC. DC is a possible complication of EB, particularly in recessive dystrophic EB. Periodic follow-up should be performed to make an early diagnosis and start treatment. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

Planar Monolithic Schottky Varactor Diode Millimeter-Wave Frequency Multipliers

DTIC Science & Technology

1992-06-01

wave applications", IEEE Trans on Microwave Theory and Tech., vol. 39, no. 12, Dec. 1991 , pp. 1964-1971. A copy of this paper is 35 included in...Watts to Bulky 1991 spectral HV DC Power line Pwr Very Inguscio varies Massive 1986 with Vac.:um line Very low Gas noise Supply Ledatron Up to 1 W at...PULSED Band up to 1985 HV DC 10 GHz Massive Pwr Magnetic V?4MA > 100 GHz > 1 Watt Wide Cooling Research Quasi- McGruer Theory Theory Band Planar 1991

To the Brain and Back: Migratory Paths of Dendritic Cells in Multiple Sclerosis.

PubMed

De Laere, Maxime; Berneman, Zwi N; Cools, Nathalie

2018-03-01

Migration of dendritic cells (DC) to the central nervous system (CNS) is a critical event in the pathogenesis of multiple sclerosis (MS). While up until now, research has mainly focused on the transmigration of DC through the blood-brain barrier, experimental evidence points out that also the choroid plexus and meningeal vessels represent important gateways to the CNS, especially in early disease stages. On the other hand, DC can exit the CNS to maintain immunological tolerance to patterns expressed in the CNS, a process that is perturbed in MS. Targeting trafficking of immune cells, including DC, to the CNS has demonstrated to be a successful strategy to treat MS. However, this approach is known to compromise protective immune surveillance of the brain. Unravelling the migratory paths of regulatory and pathogenic DC within the CNS may ultimately lead to the design of new therapeutic strategies able to selectively interfere with the recruitment of pathogenic DC to the CNS, while leaving host protective mechanisms intact. © 2018 American Association of Neuropathologists, Inc.

Model Based Optimization of Integrated Low Voltage DC-DC Converter for Energy Harvesting Applications

NASA Astrophysics Data System (ADS)

Jayaweera, H. M. P. C.; Muhtaroğlu, Ali

2016-11-01

A novel model based methodology is presented to determine optimal device parameters for the fully integrated ultra low voltage DC-DC converter for energy harvesting applications. The proposed model feasibly contributes to determine the maximum efficient number of charge pump stages to fulfill the voltage requirement of the energy harvester application. The proposed DC-DC converter based power consumption model enables the analytical derivation of the charge pump efficiency when utilized simultaneously with the known LC tank oscillator behavior under resonant conditions, and voltage step up characteristics of the cross-coupled charge pump topology. The verification of the model has been done using a circuit simulator. The optimized system through the established model achieves more than 40% maximum efficiency yielding 0.45 V output with single stage, 0.75 V output with two stages, and 0.9 V with three stages for 2.5 kΩ, 3.5 kΩ and 5 kΩ loads respectively using 0.2 V input.

An innovative high-power constant-current pulsed-arc power-supply for a high-density pulsed-arc-plasma ion-source using a LaB6-filament.

PubMed

Ueno, A; Oguri, H; Ikegami, K; Namekawa, Y; Ohkoshi, K; Tokuchi, A

2010-02-01

An innovative high-power constant-current (CC) pulsed-arc (PA) power-supply (PS) indispensable for a high-density PA plasma ion-source using a lanthanum hexaboride (LaB(6)) filament was devised by combining a constant-voltage (CV) PA-PS, which is composed of an insulated gate bipolar transistor (IGBT) switch, a CV direct-current (dc) PS and a 270 mF capacitor with a CC-PA-PS, which is composed of an IGBT-switch, a CC-dc-PS and a 400 microH inductor, through the inductor. The hybrid-CC-PA-PS succeeded in producing a flat arc-pulse with a peak power of 56 kW (400 A x 140 V) and a duty factor of more than 1.5% (600 micros x 25 Hz) for Japan Proton Accelerator Research Complex (J-PARC) H(-) ion-source stably. It also succeeded in shortening the 99% rising-time of the arc-pulse-current to about 20 micros and tilting up or down the arc-pulse-current arbitrarily and almost linearly by changing the setting voltage of its CV-dc-PS.

Simulation and optimization of a dc SQUID with finite capacitance

NASA Astrophysics Data System (ADS)

de Waal, V. J.; Schrijner, P.; Llurba, R.

1984-02-01

This paper deals with the calculations of the noise and the optimization of the energy resolution of a dc SQUID with finite junction capacitance. Up to now noise calculations of dc SQUIDs were performed using a model without parasitic capacitances across the Josephson junctions. As the capacitances limit the performance of the SQUID, for a good optimization one must take them into account. The model consists of two coupled nonlinear second-order differential equations. The equations are very suitable for simulation with an analog circuit. We implemented the model on a hybrid computer. The noise spectrum from the model is calculated with a fast Fourier transform. A calculation of the energy resolution for one set of parameters takes about 6 min of computer time. Detailed results of the optimization are given for products of inductance and temperature of LT=1.2 and 5 nH K. Within a range of β and β c between 1 and 2, which is optimum, the energy resolution is nearly independent of these variables. In this region the energy resolution is near the value calculated without parasitic capacitances. Results of the optimized energy resolution are given as a function of LT between 1.2 and 10 mH K.

SQUIDs De-fluxing Using a Decaying AC Magnetic Field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlashov, Andrei Nikolaevich; Semenov, Vasili Kirilovich; Anderson, Bill

Flux trapping is the Achilles’ heel of all superconductor electronics. The most direct way to avoid flux trapping is a prevention of superconductor circuits from exposure to magnetic fields. Unfortunately this is not feasible if the circuits must be exposed to a strong DC magnetic field even for a short period of time. For example, such unavoidable exposures take place in superparamagnetic relaxation measurements (SPMR) and ultra-low field magnetic resonance imaging (ULF MRI) using unshielded thin-film SQUID-based gradiometers. Unshielded SQUIDs stop working after being exposed to DC magnetic fields of only a few Gauss in strength. In this paper wemore » present experimental results with de-fluxing of planar thin-film LTS SQUID-based gradiometers using a strong decaying AC magnetic field. We used four commercial G136 gradiometers for SPMR measurements with up to a 10 mT magnetizing field. Strong 12.9 kHz decaying magnetic field pulses reliably return SQUIDs to normal operation 50 ms after zeroing the DC magnetizing field. This new AC de-fluxing method was also successfully tested with seven other different types of LTS SQUID sensors and has been shown to dissipate extremely low energy.« less

Combined current-modulation annealing induced enhancement of giant magnetoimpedance effect of Co-rich amorphous microwires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jingshun, E-mail: jingshun-liu@163.com, E-mail: faxiang.qin@gmail.com; School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051; Qin, Faxiang, E-mail: jingshun-liu@163.com, E-mail: faxiang.qin@gmail.com

2014-05-07

We report on a combined current-modulation annealing (CCMA) method, which integrates the optimized pulsed current (PC) and DC annealing techniques, for improving the giant magnetoimpedance (GMI) effect and its field sensitivity of Co-rich amorphous microwires. Relative to an as-prepared Co{sub 68.2}Fe{sub 4.3}B{sub 15}Si{sub 12.5} wire, CCMA is shown to remarkably improve the GMI response of the wire. At 10 MHz, the maximum GMI ratio and its field sensitivity of the as-prepared wire were, respectively, increased by 3.5 and 2.28 times when subjected to CCMA. CCMA increased atomic order orientation and circumferential permeability of the wire by the co-action of high-density pulsedmore » magnetic field energy and thermal activation energy at a PC annealing stage, as well as the formation of uniform circular magnetic domains by a stable DC magnetic field at a DC annealing stage. The magnetic moment can overcome eddy-current damping or nail-sticked action in rotational magnetization, giving rise to a double-peak feature and wider working field range (up to ±2 Oe) at relatively higher frequency (f ≥ 1 MHz)« less

Hamiltonian term for a uniform dc electric field under the adiabatic approximation

NASA Astrophysics Data System (ADS)

Siu, Zhuo Bin; Jalil, Mansoor B. A.; Tan, Seng Ghee

2018-02-01

In this work, we show that the disorder-free Kubo formula for the nonequilibrium value of an observable due to a dc electric field, represented by Exx ̂ in the Hamiltonian, can be interpreted as the standard time-independent theory response of the observable due to a time- and position-independent perturbation HMF. We derive the explicit expression for HMF and show that it originates from the adiabatic approximation to

Hepatic dendritic cell subsets in the mouse.

PubMed

Jomantaite, Ieva; Dikopoulos, Nektarios; Kröger, Andrea; Leithäuser, Frank; Hauser, Hansjörg; Schirmbeck, Reinhold; Reimann, Jörg

2004-02-01

The CD11c(+) cell population in the non-parenchymal cell population of the mouse liver contains dendritic cells (DC), NK cells, B cells and T cells. In the hepatic CD11c(+) DC population from immunocompetent or immunodeficient [recombinase-activating gene-1 (RAG1)(-/-)] C57BL/6 mice (rigorously depleted of T cells, B cells and NK cells), we identified a B220(+) CD11c(int) subset of 'plasmacytoid' DC, and a B220(-) CD11c(+) DC subset. The latter DC population could be subdivided into a major, immature (CD40(lo) CD80(lo) CD86(lo) MHC class II(lo)) CD11c(int) subset, and a minor, mature (CD40(hi) CD80(hi) CD86(hi) MHC class II(hi)) CD11c(hi) subset. Stimulated B220(+) but not B220(-) DC produced type I interferon. NKT cell activation in vivo increased the number of liver B220(-) DC three- to fourfold within 18 h post-injection, and up-regulated their surface expression of activation marker, while it contracted the B220(+) DC population. Early in virus infection, the hepatic B220(+) DC subset expanded, and both, the B220(+) as well as B220(-) DC populations in the liver matured. In vitro, B220(-) but not B220(+) DC primed CD4(+) or CD8(+)T cells. Expression of distinct marker profiles and functions, and distinct early reaction to activation signals hence identify two distinct B220(+) and B220(-) subsets in CD11c(+) DC populations freshly isolated from the mouse liver.

DC coupled Doppler radar physiological monitor.

PubMed

Zhao, Xi; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

2011-01-01

One of the challenges in Doppler radar systems for physiological monitoring is a large DC offset in baseband outputs. Typically, AC coupling is used to eliminate this DC offset. Since the physiological signals of interest include frequency content near DC, it is not desirable to simply use AC coupling on the radar outputs. While AC coupling effectively removes DC offset, it also introduces a large time delay and distortion. This paper presents the first DC coupled IQ demodulator printed circuit board (PCB) design and measurements. The DC coupling is achieved by using a mixer with high LO to RF port isolation, resulting in a very low radar DC offset on the order of mV. The DC coupled signals from the PCB radar system were successfully detected with significant LNA gain without saturation. Compared to the AC coupled results, the DC coupled results show great advantages of less signal distortion and more accurate rate estimation.

26 CFR 1.897-2 - United States real property holding corporations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... value of $500,000. DC's only real property interest was a factory that it had occupied for over 50 years, which had a book value of $200,000. The factory was located in a deteriorated downtown area, and DC had... time of DC's December 31, 1989 determination date, the downtown area in which DC's factory was located...

26 CFR 1.897-2 - United States real property holding corporations.

Code of Federal Regulations, 2012 CFR

2012-04-01

... value of $500,000. DC's only real property interest was a factory that it had occupied for over 50 years, which had a book value of $200,000. The factory was located in a deteriorated downtown area, and DC had... time of DC's December 31, 1989 determination date, the downtown area in which DC's factory was located...

26 CFR 1.897-2 - United States real property holding corporations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... value of $500,000. DC's only real property interest was a factory that it had occupied for over 50 years, which had a book value of $200,000. The factory was located in a deteriorated downtown area, and DC had... time of DC's December 31, 1989 determination date, the downtown area in which DC's factory was located...

26 CFR 1.897-2 - United States real property holding corporations.

Code of Federal Regulations, 2014 CFR

2014-04-01

... value of $500,000. DC's only real property interest was a factory that it had occupied for over 50 years, which had a book value of $200,000. The factory was located in a deteriorated downtown area, and DC had... time of DC's December 31, 1989 determination date, the downtown area in which DC's factory was located...

Electrodeposited Nanolaminated CoNiFe Cores for Ultracompact DC-DC Power Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J; Kim, M; Herrault, F

2015-09-01

Laminated metallic alloy cores (i.e., alternating layers of thin film metallic alloy and insulating material) of appropriate lamination thickness enable suppression of eddy current losses at high frequencies. Magnetic cores comprised of many such laminations yield substantial overall magnetic volume, thereby enabling high-power operation. Previously, we reported nanolaminated permalloy (Ni-80 Fe-20) cores based on a sequential electrodeposition technique, demonstrating negligible eddy current losses at peak flux densities up to 0.5 T and operating at megahertz frequencies. This paper demonstrates improved performance of nanolaminated cores comprising tens to hundreds of layers of 300-500-nm-thick CoNiFe films that exhibit superior magnetic properties (e.g.,more » higher saturation flux density and lower coercivity) than permalloy. Nanolaminated CoNiFe cores can be operated up to a peak flux density of 0.9 T, demonstrating improved power handling capacity and exhibiting 30% reduced volumetric core loss, attributed to lowered hysteresis losses compared to the nanolaminated permalloy core of the same geometry. Operating these cores in a buck dc-dc power converter at a switching frequency of 1 MHz, the nanolaminated CoNiFe cores achieved a conversion efficiency exceeding 90% at output power levels up to 7 W, compared to an achieved permalloy core conversion efficiency below 86% at 6 W.« less

Boon or bane: 401(k) loans and employee contributions.

PubMed

Wenger, Jeffrey B; Weller, Christian E

2014-09-01

Economic and behavioral theories arrive at different conclusions about the effect of being allowed to borrow from one's defined-contribution (DC) retirement plan on people's contributions to DC plans. Traditional life-cycle models unambiguously suggest that the borrowing option makes people better off than not being able to borrow. Households consequently contribute more to their DC plans than they would absent the borrowing option. Previous research finds that the ability to borrow from a DC plan increases contemporaneous contributions, consistent with traditional models. Behavioral finance, in contrast, suggests that some workers may operate with nonlinear time discounting. They plan on saving more in the future but change their mind and save less than initially planned as time passes. These workers may enjoy higher lifetime utility if they have no loan option because DC plans serve as commitment devices for retirement saving. The money cannot be used prior to retirement. Absent this commitment device, contributions may be lower for some households than would be the case without a DC loan option. We study DC plan contributions for households with heterogeneous preferences about discounting. We separate households into those that demonstrate inconsistent (or paradoxical) borrowing behavior, which may reflect nonlinear time discounting, and those with more consistent borrowing behavior. We find that a DC loan option raises current savings, but does so more for households with consistent borrowing behavior than for those with inconsistent borrowing behavior. © The Author(s) 2013.

Encephalitozoon intestinalis Inhibits Dendritic Cell Differentiation through an IL-6-Dependent Mechanism

PubMed Central

Bernal, Carmen E.; Zorro, Maria M.; Sierra, Jelver; Gilchrist, Katherine; Botero, Jorge H.; Baena, Andres; Ramirez-Pineda, Jose R.

2016-01-01

Microsporidia are a group of intracellular pathogens causing self-limited and severe diseases in immunocompetent and immunocompromised individuals, respectively. A cellular type 1 adaptive response, mediated by IL-12, IFNγ, CD4+, and CD8+ T cells has been shown to be essential for host resistance, and dendritic cells (DC) play a key role at eliciting anti-microsporidial immunity. We investigated the in vitro response of DC and DC precursors/progenitors to infection with Encephalitozoon intestinalis (Ei), a common agent of human microsporidosis. Ei-exposed DC cultures up-regulated the surface expression of MHC class II and the costimulatory molecules CD86 and CD40, only when high loads of spores were used. A vigorous secretion of IL-6 but not of IL-1β or IL-12p70 was also observed in these cultures. Ei-exposed DC cultures consisted of immature infected and mature bystander DC, as assessed by MHC class II and costimulatory molecules expression, suggesting that intracellular Ei spores deliver inhibitory signals in DC. Moreover, Ei selectively inhibited the secretion of IL-12p70 in LPS-stimulated DC. Whereas Ei-exposed DC promoted allogeneic naïve T cell proliferation and IL-2 and IFNγ secretion in DC-CD4+ T cell co-cultures, separated co-cultures with bystander or infected DCs showed stimulation or inhibition of IFNγ secretion, respectively. When DC precursors/progenitors were exposed to Ei spores, a significant inhibition of DC differentiation was observed without shifting the development toward cells phenotypically or functionally compatible with myeloid-derived suppressor cells. Neutralization experiments demonstrated that this inhibitory effect is IL-6-dependent. Altogether this investigation reveals a novel potential mechanism of immune escape of microsporidian parasites through the modulation of DC differentiation and maturation. PMID:26870700

Global Observations of Inorganic Gases in the Remote Atmosphere - First Observations from the Atmospheric Tomography Mission (ATom)

NASA Astrophysics Data System (ADS)

Veres, P. R.; Neuman, J. A.

2017-12-01

The Atmospheric Tomography Mission (ATom) is a NASA field program that investigates the impact of human emissions on air quality and climate in remote regions of the atmosphere. NASA DC-8 flights during the ATom sampled the atmosphere over the Pacific and Atlantic Oceans, up to 12 km altitude and nearly from pole to pole. New observations of key species (e.g. N2O5, reactive halogens, nitrous acid) in these regions are provided during the third deployment of the NASA DC-8 research aircraft (October, 2017) by the NOAA iodide ion time-of-flight chemical ionization mass spectrometer (iCIMS). In this study, we will present the first observations of inorganic gas-phase species using iCIMS from the ATom 3 deployment. Laboratory results detailing the instrument performance including inlet response times, background characterization and sensitivity will be presented. We will show vertical profiles of newly measured trace gases derived from in-situ observations, and discuss the potential impact on the NOx, NOy and reactive halogen budgets.

Toward characterization of Huber's ball-bearing motor

NASA Astrophysics Data System (ADS)

Choo, Joo Liang; Soong, Wen Liang; Abbott, Derek

2005-02-01

A motor that can be powered up by either a DC or AC supply and rotates in either direction, based on the so-called Huber effect, is investigated. For the first time, this paper examines the motor characteristics under both DC and AC conditions, for quantitative comparisons. Earlier work has not examined, in detail, the effect of an AC supply on the Huber motor operation. Previous work on the Huber or ball-bearing motor suffered from alignment problems and here we describe a new methodology to address this. The new construction is also a step toward a micromotor realization. The motor, with its reduced dimensions, also has the advantage of reduced operating current. Since 1959, the principle of operation of this motor has remained an unsolved mystery and various theories exist in the literature. We show various empirical findings that shed some light on the hotly contested debate. The discovery of carbon on the bearings, under AC supply conditions, reported here creates a new open question. Motor acceleration versus torque characteristics are obtained, using a data acquisition system to facilitate dynamic real-time recording.

An inexpensive particle monitor for smoker behaviour modification in homes.

PubMed

Semple, Sean; Apsley, Andrew; Maccalman, Laura

2013-09-01

To compare the response of a new particle counting instrument (Dylos DC1700) with that produced by a device (TSI Sidepak Personal Aerosol Monitor AM510) commonly used to measure PM2.5 in settings where secondhand smoke (SHS) is encountered. Controlled chamber experiments with different SHS concentrations were generated by burning a cigarette for varying time periods and running both devices simultaneously. The Dylos and Sidepak devices produced similar responses to changes in SHS concentrations up to 1000 μg/m(3). Using 591 min of contemporaneous measurements from 13 chamber experiments, an equation was developed to allow conversion of particle number concentration data from the Dylos to estimated mass concentration data for SHS aerosol. The Dylos DC1700 can provide real-time data that may be converted to an estimate of SHS levels in smoky environments. Given the low cost, low noise and simplicity of use, this device is likely to be a useful tool for interventions to provide feedback of SHS concentrations to help motivate changes in smoking behaviour at home.

Thermal Simulation of a Silicon Carbide (SiC) Insulated-Gate Bipolar Transistor (IGBT) in Continuous Switching Mode

DTIC Science & Technology

operation in a DC-DC power converter switching at a frequency of up to 15 kHz. Calculations also estimated the effect of solder layers on temperature in the device....Thermal simulations were used to calculate temperatures in a silicon carbide (SiC) Insulated -Gate Bipolar Transistor (IGBT),simulating device

Drunk Driving. Surgeon General's Workshop. Proceedings (Washington, D.C., December 14-16, 1988).

ERIC Educational Resources Information Center

Janus Associates.

This volume presents solutions, recommendations, and strategies in eleven interrelated areas considered at the Surgeon General's Workshop on Drunk Driving held in Washington, D.C. in December of 1988. Lists of the members of the Workshop Planning Committee and members of the federal advisory group on follow-up activities for the workshop are…

2003-2013, a valuable study: Autologous tumor lysate-pulsed dendritic cell immunotherapy with cytokine-induced killer cells improves survival in stage IV breast cancer.

PubMed

Lin, Mao; Liang, Shuzhen; Jiang, Feng; Xu, Jiongyuan; Zhu, Weibing; Qian, Wei; Hu, Yong; Zhou, Zhanchun; Chen, Jibing; Niu, Lizhi; Xu, Kecheng; Lv, Youyong

2017-03-01

Dendritic cells (DCs) and cytokine-induced killer (CIK) cells have both shown activity as immunotherapy in some malignancies. Our aim was to prospective assess the effect of this immunotherapy in patients with stage IV breast cancer. Between Aug 2003 and Dec 2013, we collected 368 patients who met inclusion criteria and divided into immunotherapy group (treatment group: 188 patients) and chemotherapy group (control group: 180 patients). DCs were prepared from the mononuclear cells isolated from patients in the treatment group using IL-2/GM-CSF and were loaded with tumour antigens; CIK cells were prepared by incubating peripheral blood lymphocytes with IL-2, IFN-γ, and CD3 antibodies. After the patients had received low-dose chemotherapy, those in the treatment group also received the DC-CIK therapy, which was repeated four times in a fortnight to form one cycle. At least three cycles of DC-CIK therapy were given. Immune function was measured in treatment group patients' sera. Disease-free survival (DFS) and Overall survival (OS) after the diagnosis of stage IV breast cancer was assessed after a 10-year follow-up. The result demonstrated that immune function is obviously enhanced after DC-CIK therapy. By Cox regression analysis, DC-CIK therapy reduced the risk of disease progression (p<0.01) with an increased OS (p<0.01). After low-dose chemotherapy, active immunization with DC-CIK immunotherapy is a potentially effective approach for the control of tumour growth in stage IV breast cancer patients. Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

Time-dependent deformation of polymer network in polymer-stabilized cholesteric liquid crystals (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lee, Kyung Min; Tondiglia, Vincent P.; Bunning, Timothy J.; White, Timothy J.

2017-02-01

Recently, we reported direct current (DC) field controllable electro-optic (EO) responses of negative dielectric anisotropy polymer stabilized cholesteric liquid crystals (PSCLCs). A potential mechanism is: Ions in the liquid crystal mixtures are trapped in/on the polymer network during the fast photopolymerization process, and the movement of ions by the application of the DC field distorts polymer network toward the negative electrode, inducing pitch variation through the cell thickness, i.e., pitch compression on the negative electrode side and pitch expansion on positive electrode side. As the DC voltage is directly applied to a target voltage, charged polymer network is deformed and the reflection band is tuned. Interestingly, the polymer network deforms further (red shift of reflection band) with time when constantly applied DC voltage, illustrating DC field induced time dependent deformation of polymer network (creep-like behavior). This time dependent reflection band changes in PSCLCs are investigated by varying the several factors, such as type and concentration of photoinitiators, liquid crystal monomer content, and curing condition (UV intensity and curing time). In addition, simple linear viscoelastic spring-dashpot models, such as 2-parameter Kelvin and 3-parameter linear models, are used to investigate the time-dependent viscoelastic behaviors of polymer networks in PSCLC.

Long-term effects of handheld cell phone laws on driver handheld cell phone use.

PubMed

McCartt, Anne T; Hellinga, Laurie A; Strouse, Laura M; Farmer, Charles M

2010-04-01

As of October 2009, seven U.S. states and the District of Columbia (D.C.) ban driving while talking on a handheld cell phone. Long-term effects on driver handheld phone use in D.C., New York State, and Connecticut were examined. The percentage of drivers talking on handheld cell phones was measured over time with daytime observation surveys in the jurisdictions with bans and comparison jurisdictions without bans. Trends were modeled using Poisson regression to estimate differences between actual rates and rates that would have been expected without a ban. The D.C. ban immediately lowered the percentage of drivers talking on handheld cell phones by 41 percent. Nearly 5 years later, the rate was 43 percent lower than would have been expected without the ban. Use in Connecticut declined 76 percent immediately after the ban; 3.5 years later, use was 65 percent lower than would have been expected without the ban. In New York, use declined 47 percent immediately after the ban; 7 years later, use was 24 percent lower than expected without the ban. Fifteen months after the laws took effect, compliance in New York was lower than in D.C., and the difference appeared due to more intensive enforcement in D.C. However, this linkage is no longer clear because enforcement in New York picked up such that 2008 levels of enforcement appeared comparable in D.C. and New York, whereas enforcement in Connecticut lagged behind. In all three jurisdictions, the chance that a violator would receive a citation was low, and there were no publicized targeted enforcement campaigns. Jurisdictional bans have reduced handheld phone use and appear capable of maintaining reductions for the long term. However, it is unknown whether overall phone use is lower because many drivers may have switched to hands-free devices. Further research is needed to determine whether reduced handheld cell phone use has reduced crashes.

A novel dendritic cell-based immunization approach for the induction of durable Th1-polarized anti-HER-2/neu responses in women with early breast cancer

PubMed Central

Koski, Gary K.; Koldovsky, Ursula; Xu, Shuwen; Mick, Rosemarie; Sharma, Anupama; Fitzpatrick, Elizabeth; Weinstein, Susan; Nisenbaum, Harvey; Levine, Bruce L; Fox, Kevin; Zhang, Paul; Czerniecki, Brian J

2011-01-01

Twenty-seven subjects with HER-2/neu over-expressing ductal carcinoma in situ of the breast were enrolled in a neoadjuvant immunization trial for safety and immunogenicity of DC1-polarized dendritic cells (DC1) pulsed with six HER-2/neu promiscuous MHC class II-binding peptides, plus two additional HLA-A2.1 class I-binding peptides. DC1 were generated with IFN-γ plus a special clinical-grade bacterial endotoxin (LPS) and administered directly into groin lymph nodes four times at weekly intervals prior to scheduled surgical resection of DCIS. Subjects were monitored for the induction of new or enhanced anti-peptide reactivity by IFN-γ ELIspot and ELISA assays performed on Th cells obtained from peripheral blood or excised sentinel lymph nodes. Responses by CTL against HLA-A2.1-binding peptides were measured using peptide-pulsed T2 target cells or HER-2/neu-expressing or non-expressing tumor cell lines. DC1 showed surface phenotype indistinct from “gold standard” inflammatory cocktail-activated DC, but displayed a number of distinguishing functional characteristics including the secretion of soluble factors and enhanced “killer DC” capacity against tumor cells in vitro. Post-immunization, we observed sensitization of Th cells to at least 1 class II peptide in 22 of 25 (88%, 95% exact CI 68.8 – 97.5%) evaluable subjects, while eleven of 13 (84.6%, 95% exact CI 64 – 99.8%) HLA-A2.1 subjects were successfully sensitized to class I peptides. Perhaps most importantly, anti-HER-2/neu peptide responses were observed up to 52 months post-immunization. These data show even in the presence of early breast cancer such DC1 are potent inducers of durable type I-polarized immunity, suggesting potential clinical value for development of cancer immunotherapy. PMID:22130160

Pseudo ribbon metal ion beam source.

PubMed

Stepanov, Igor B; Ryabchikov, Alexander I; Sivin, Denis O; Verigin, Dan A

2014-02-01

The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

Fatty acids isolated from royal jelly modulate dendritic cell-mediated immune response in vitro.

PubMed

Vucevic, Dragana; Melliou, Eleni; Vasilijic, Sasa; Gasic, Sonja; Ivanovski, Petar; Chinou, Ioanna; Colic, Miodrag

2007-09-01

Royal jelly (RJ), especially its protein components, has been shown to possess immunomodulatory activity. However, almost nothing is known about the influence of RJ fatty acids on the immune system. In this work we studied the effect of 10-hydroxy-2-decanoic acid (10-HDA) and 3,10-dihydroxy-decanoic acid (3,10-DDA), isolated from RJ, on the immune response using a model of rat dendritic cell (DC)-T-cell cocultures. Both fatty acids, at higher concentrations, inhibited the proliferation of allogeneic T cells. The effect of 10-HDA was stronger and was followed by a decrease in interleukin-2 (IL-2) production and down-regulation of IL-2 receptor expression. Spleen DC, cultivated with 10 microg/ml of fatty acids down-regulated the expression of CD86 and the production of IL-12, but up-regulated the production of IL-10. In contrast, DC, pretreated with 100 microg/ml of 3,10-DDA, up-regulated the expression of CD86 and augmented the proliferation of allogeneic T cells. The highest dose (200 microg/ml) of both fatty acids which was non-apoptotic for both T cells and DC, down-regulated the expression of MHC class II and CD86, decreased the production of IL-12 and made these DC less allostimulatory. The immunosuppressive activity of 3,10-DDA was also confirmed in vivo, using a model of Keyhole lymphet hemocyanine immunization of rats. In conclusion, our results showed the immunomodulatory activity of RJ fatty acids and suggest that DC are a significant target of their action.

Outcome assessment of decentralization of antiretroviral therapy provision in a rural district of Malawi using an integrated primary care model.

PubMed

Chan, Adrienne K; Mateyu, Gabriel; Jahn, Andreas; Schouten, Erik; Arora, Paul; Mlotha, William; Kambanji, Marion; van Lettow, Monique

2010-06-01

To assess the effect of decentralization (DC) of antiretroviral therapy (ART) provision in a rural district of Malawi using an integrated primary care model. Between October 2004 and December 2008, 8093 patients (63% women) were registered for ART. Of these, 3440 (43%) were decentralized to health centres for follow-up ART care. We applied multivariate regression analysis that adjusted for sex, age, clinical stage at initiation, type of regimen, presence of side effects because of ART, and duration of treatment and follow-up at site of analysis. Patients managed at health centres had lower mortality [adjusted OR 0.19 (95% C.I. 0.15-0.25)] and lower loss to follow-up (defaulted from treatment) [adjusted OR 0.48 (95% C.I. 0.40-0.58)]. During the first 10 months of follow-up, those decentralized to health centres were approximately 60% less likely to default than those not decentralized; and after 10 months of follow-up, 40% less likely to default. DC was significantly associated with a reduced risk of death from 0 to 25 months of follow-up. The lower mortality may be explained by the selection of stable patients for DC, and the mentorship and supportive supervision of lower cadre health workers to identify and refer complicated cases. Decentralization of follow-up ART care to rural health facilities, using an integrated primary care model, appears a safe and effective way to rapidly scale-up ART and improves both geographical equity in access to HIV-related services and adherence to ART.

The serologic decoy receptor 3 (DcR3) levels are associated with slower disease progression in HIV-1/AIDS patients.

PubMed

Lin, Yu-Ting; Yen, Chia-Hung; Chen, Heng-Li; Liao, Yi-Jen; Lin, I-Feng; Chen, Marcelo; Lan, Yu-Ching; Chuang, Shao-Yuan; Hsieh, Shie-Liang; Chen, Yi-Ming Arthur

2015-06-01

The decoy receptor 3 (DcR3) is a member of the tumor necrosis factor receptor (TNFR) super-family. It counteracts the biological effects of Fas ligands and inhibits apoptosis. The goals of this study were to understand the associations between serologic DcR3 (sDcR3) levels and different human immunodeficiency virus type 1 (HIV-1) subtypes, as well as the AIDS disease progression. Serum samples from 61 HIV/AIDS patients, who had been followed up every 6 months for 3 years, were collected. sDcR3 levels were quantified using an enzyme immunoassay (EIA). The sDcR3 levels in patients with HIV-1 subtype B were significantly higher than those in patients infected with subtype CRF01_AE (p < 0.001). In addition, multivariable linear mixed model analysis demonstrated that HIV-1 subtype B and slow disease progression were associated with higher levels of sDcR3, adjusting for potential predictors (p = 0.0008 and 0.0455, respectively). HIV-1-infected cells may gain a survival advantage by activating DcR3, which prevents infected cell detection by the host immune system. These data indicate that the sDcR3 level is a biomarker for AIDS disease progression. Copyright © 2013. Published by Elsevier B.V.

Strategic and Operational Considerations for the Implementation of Performance Based Logistics (PBL) Within the Japan Maritime Self Defense Force

DTIC Science & Technology

2010-06-01

logistics in support of weapon systems (D-2004-110). Washington, DC: Young , S. R. Keating , S., & Huff, K. (2005). Managing risk in the new supply chain...implementing PBL ( Keating & Huff, 2005; Reeve, 2001). Cohen (2007) found that cost-sharing support and maintenance services can generate "up to seven times as...to suppliers (Cohen, 2007; Keating & Huff, 2005); therefore, suppliers demand a risk premium (Cohen, & Nines, 2008). The degree of risk

Studies of ZVS soft switching of dual-active-bridge isolated bidirectional DC-DC converters

NASA Astrophysics Data System (ADS)

Xu, Fei; Zhao, Feng; Shi, Qibiao; Wen, Xuhui

2018-05-01

To operate dual-active-bridge isolated bidirectional dc- dc converter (DAB) at high efficiency, the two bridge switches must operate with Zero-Voltage-Switching (ZVS) over as wide an operating range as possible. This paper proposes a new perspective on realizing ZVS in dead-time. An exact theoretical analysis and mathematical mode is built to explain the process of ZVS switching in dead-time under Single Phase Shift (SPS) control strategy. In order to assure the two bridge switches operate on soft switching, every SPS switching point is analyzed. Generally, dead-time will be determined when the power electronic devices is selected. The key factor to realizing ZVS is the size of the end time of resonance comparing to dead-time. Through detailed analysis, it can obtain the conditions of all switches achieving ZVS turn-on and turn-off. Finally, simulation validates the theoretical analysis and some advice are given to realize the ZVS soft switching.

High-frequency high-voltage high-power DC-to-DC converters

NASA Technical Reports Server (NTRS)

Wilson, T. G.; Owen, H. A.; Wilson, P. M.

1982-01-01

A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

High-frequency high-voltage high-power DC-to-DC converters

NASA Astrophysics Data System (ADS)

Wilson, T. G.; Owen, H. A.; Wilson, P. M.

1982-09-01

A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

Self-oscillations in field emission nanowire mechanical resonators: a nanometric dc-ac conversion.

PubMed

Ayari, Anthony; Vincent, Pascal; Perisanu, Sorin; Choueib, May; Gouttenoire, Vincent; Bechelany, Mikhael; Cornu, David; Purcell, Stephen T

2007-08-01

We report the observation of self-oscillations in a bottom-up nanoelectromechanical system (NEMS) during field emission driven by a constant applied voltage. An electromechanical model is explored that explains the phenomenon and that can be directly used to develop integrated devices. In this first study, we have already achieved approximately 50% dc/ac (direct to alternating current) conversion. Electrical self-oscillations in NEMS open up a new path for the development of high-speed, autonomous nanoresonators and signal generators and show that field emission (FE) is a powerful tool for building new nanocomponents.

Controller for a High-Power, Brushless dc Motor

NASA Technical Reports Server (NTRS)

Fleming, David J.; Makdad, Terence A.

1987-01-01

Driving and braking torques controllable. Control circuit operates 7-kW, 45-lb-ft (61-N-m), three-phase, brushless dc motor in both motor and generator modes. In motor modes, energy from power source is pulse-width modulated to motor through modified "H-bridge" circuit, in generator mode, energy from motor is pulse-width modulated into bank of load resistors to provide variable braking torques. Circuit provides high-resolution torque control in both directions over wide range of speeds and torques. Tested successfully at bus voltages up to 200 Vdc and currents up to 45 A.

Characterization of colonic dendritic cells in normal and colitic mice.

PubMed

Cruickshank, Sheena M; English, Nicholas R; Felsburg, Peter J; Carding, Simon R

2005-10-28

Recent studies demonstrating the direct involvement of dendritic cells (DC) in the activation of pathogenic T cells in animal models of inflammatory bowel disease identify DC as important antigen presenting cells in the colon. However, very little is known about the properties of colonic DC. Using immunohistochemistry, electron microscopy and flow cytometry we have characterized and compared colonic DC in the colon of healthy animals and interleukin-2-deficient (IL2(-/-)) mice that develop colitis. In the healthy colon, DC resided within the lamina propria and in close association with the basement membrane of colonic villi. Type 1 myeloid (CD11c(+), CD11b(+), B220(-), CD8alpha(-)) DC made up the largest (40-45%) population and all DC expressed low levels of CD80, CD86, and CD40, and had high endocytic activity consistent with an immature phenotype. In colitic IL2(-/-) mice, colonic DC numbers increased four- to five-fold and were localized within the epithelial layer and within aggregates of T and B cells. They were also many more DC in mesenteric lymph nodes (MLN). The majority (>85%) of DC in the colon and MLN of IL2(-/-) mice were type 1 myeloid, and expressed high levels of MHC class II, CD80, CD86, CD40, DEC 205, and CCR5 molecules and were of low endocytic activity consistent with mature DC. These findings demonstrate striking changes in the number, distribution and phenotype of DC in the inflamed colon. Their intimate association with lymphocytes in the colon and draining lymph nodes suggest that they may contribute directly to the ongoing inflammation in the colon.

Characterization of colonic dendritic cells in normal and colitic mice

PubMed Central

Cruickshank, Sheena M; English, Nicholas R; Felsburg, Peter J; Carding, Simon R

2005-01-01

AIM: Recent studies demonstrating the direct involvement of dendritic cells (DC) in the activation of pathogenic T cells in animal models of inflammatory bowel disease identify DC as important antigen presenting cells in the colon. However, very little is known about the properties of colonic DC. METHODS: Using immunohistochemistry, electron microscopy and flow cytometry we have characterized and compared colonic DC in the colon of healthy animals and interleukin-2-deficient (IL2-/-) mice that develop colitis. RESULTS: In the healthy colon, DC resided within the lamina propria and in close association with the basement membrane of colonic villi. Type 1 myeloid (CD11c+, CD11b+, B220-, CD8α-) DC made up the largest (40-45%) population and all DC expressed low levels of CD80, CD86, and CD40, and had high endocytic activity consistent with an immature phenotype. In colitic IL2-/- mice, colonic DC numbers increased four- to five-fold and were localized within the epithelial layer and within aggregates of T and B cells. They were also many more DC in mesenteric lymph nodes (MLN). The majority (>85%) of DC in the colon and MLN of IL2-/- mice were type 1 myeloid, and expressed high levels of MHC class II, CD80, CD86, CD40, DEC 205, and CCR5 molecules and were of low endocytic activity consistent with mature DC. CONCLUSION: These findings demonstrate striking changes in the number, distribution and phenotype of DC in the inflamed colon. Their intimate association with lymphocytes in the colon and draining lymph nodes suggest that they may contribute directly to the ongoing inflammation in the colon. PMID:16419163

DcR3, a new biomarker for sepsis, correlates with infection severity and procalcitonin.

PubMed

Gao, Liqin; Yang, Bin; Zhang, Hairong; Ou, Qishui; Lin, Yulan; Zhang, Mei; Zhang, Zhenhuan; Kim, Sunghee; Wu, Bing; Wang, Zeng; Fu, Lengxi; Lin, Jingan; Chen, Ruiqing; Lan, Ruilong; Chen, Junying; Chen, Wei; Chen, Long; Zhang, Hengshan; Han, Deping; Chen, Jingrong; Okunieff, Paul; Lin, Jianhua; Zhang, Lurong

2018-02-16

Early diagnosis of sepsis is critical for successful treatment. The clinical value of DcR3 in early diagnosis of sepsis was determined in a dynamic follow-up study. Alterations in plasma levels of DcR3, PCT, CRP, and IL-6 were measured by ELISA and compared among patients with sepsis ( n = 134), SIRS ( n = 60) and normal adults ( n = 50). Correlations and dynamic patterns among the biomarkers, APACHE II scores, clinical outcomes, and pathogens were also examined. Plasma DcR3 was significantly increased in sepsis compared to SIRS and normal adults (median 3.87 vs. 1.28 and 0.17 ng/ml). The elevated DcR3 could be detected in 97.60% sepsis patients 1-2 days prior to the result of blood culture reported. For diagnosis of sepsis, the sensitivity was 97.69% and specificity 98.04%; and for differential diagnosis of sepsis from SIRS, the sensitivity was 90.77% and specificity 98.40%. DcR3 level was positively correlated with severity of sepsis ( r s = 0.82). In 41 patients who died of sepsis, DcR3 elevated as early as 1-2 days before blood culture and peaked on day 3 after blood culture performed. In 90% of sepsis patients, the dynamic alteration pattern of DcR3 was identical to that of PCT, while pattern of 10% patients differed in which clinical data was consistent with DcR3. In 13% sepsis patients, while PCT remained normal, DcR3 levels were at a high level. DcR3 levels had no difference among various pathogens infected. DcR3, a new biomarker, will aid in early diagnosis of sepsis and monitoring its outcome, especially when sepsis patients were PCT negative.

A novel concept of fault current limiter based on saturable core in high voltage DC transmission system

NASA Astrophysics Data System (ADS)

Yuan, Jiaxin; Zhou, Hang; Gan, Pengcheng; Zhong, Yongheng; Gao, Yanhui; Muramatsu, Kazuhiro; Du, Zhiye; Chen, Baichao

2018-05-01

To develop mechanical circuit breaker in high voltage direct current (HVDC) system, a fault current limiter is required. Traditional method to limit DC fault current is to use superconducting technology or power electronic devices, which is quite difficult to be brought to practical use under high voltage circumstances. In this paper, a novel concept of high voltage DC transmission system fault current limiter (DCSFCL) based on saturable core was proposed. In the DCSFCL, the permanent magnets (PM) are added on both up and down side of the core to generate reverse magnetic flux that offset the magnetic flux generated by DC current and make the DC winding present a variable inductance to the DC system. In normal state, DCSFCL works as a smoothing reactor and its inductance is within the scope of the design requirements. When a fault occurs, the inductance of DCSFCL rises immediately and limits the steepness of the fault current. Magnetic field simulations were carried out, showing that compared with conventional smoothing reactor, DCSFCL can decrease the high steepness of DC fault current by 17% in less than 10ms, which verifies the feasibility and effectiveness of this method.

Method and device for ion mobility separations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibrahim, Yehia M.; Garimella, Sandilya V. B.; Smith, Richard D.

2017-07-11

Methods and devices for ion separations or manipulations in gas phase are disclosed. The device includes a single non-planar surface. Arrays of electrodes are coupled to the surface. A combination of RF and DC voltages are applied to the arrays of electrodes to create confining and driving fields that move ions through the device. The DC voltages are static DC voltages or time-dependent DC potentials or waveforms.

Adverse effect on syngeneic islet transplantation by transgenic coexpression of decoy receptor 3 and heme oxygenase-1 in the islet of NOD mice.

PubMed

Huang, S-H; Lin, G-J; Chien, M-W; Chu, C-H; Yu, J-C; Chen, T-W; Hueng, D-Y; Liu, Y-L; Sytwu, H-K

2013-03-01

Decoy receptor 3 (DcR3) blocks both Fas ligand- and LIGHT-induced pancreatic β-cell damage in autoimmune diabetes. Heme oxygenase 1 (HO-1) possesses antiapoptotic, anti-inflammatory, and antioxidative effects that protect cells against various forms of attack by the immune system. Previously, we have demonstrated that transgenic islets overexpressing DcR3 or murine HO-1 (mHO-1) exhibit longer survival times than nontransgenic islets in syngeneic islet transplantation. In this study, we evaluated whether DcR3 and mHO-1 double-transgenic islets of NOD mice could provide better protective effects and achieve longer islet graft survival than DcR3 or mHO-1 single-transgenic islets after islet transplantation. We generated DcR3 and mHO-1 double-transgenic NOD mice that specifically overexpress DcR3 and HO-1 in islets. Seven hundred islets isolated from double-transgenic, single-transgenic, or nontransgenic NOD mice were syngeneically transplanted into the kidney capsules of newly diabetic female recipients. Unexpectedly, there was no significant difference in the survival time between double-transgenic or nontransgenic NOD islet grafts, and the survival times of double-transgenic NOD islet grafts were even shorter than those of DcR3 or mHO-1 single-transgenic islets. Our data indicate that transplantation of double-transgenic islets that coexpress HO-1 and DcR3 did not result in a better outcome. On the contrary, this strategy even caused an adverse effect in syngeneic islet transplantation. Copyright © 2013 Elsevier Inc. All rights reserved.

Advances in spectral conversion for photovoltaics: up-converting Er3+ doped YF3 nano-crystals in transparent glass ceramic

NASA Astrophysics Data System (ADS)

Marques-Hueso, Jose; Chen, Daqin; MacDougall, Sean K. W.; Wang, Yuansheng; Richards, Bryce S.

2011-09-01

Up- and down-conversion (UC, DC) constitute two singular routes to achieve improved energy harvesting of sunlight by changing its shape of the solar spectrum. To obtain a significant conversion rate two main challenges have to be overcome: i) the excited lanthanide ions have to emit efficiently, a target which has been better accomplished for DC materials; ii) the absorption in the lanthanide-based UC and DC layers has to be high to ensure a sizeable fraction of photons can be harvested. In this paper, we review such materials and their use as spectral converters for photovoltaics (PV), paying special attention to the UC and DC processes in lanthanide glasses in fluoride matrices. We discuss the challenges that need to be overcome in order to implement these materials in real PV devices. Finally, we will present the synthesis of erbium (Er3+) doped YF3 nano-crystals embedded in transparent glass ceramic (TGC) by melt quenching. This material presents a low phonon energy environment for the Er3+ ions due to the fluoride crystals, while the silica glass provides chemical and mechanical stability to the compound.

DC-8 Airborne Laboratory in flight

NASA Image and Video Library

1998-02-20

The NASA DC-8 in a right bank over the rugged Sierra Nevada Mountains. The former airliner is a "dash-72" model and has a range of 5,500 miles. The craft can stay airborne for 12 hours and has an operational speed range between 300 and 500 knots. The research flights are made at between 500 and 41,000 feet. The aircraft can carry up to 30,000 lbs of research/science payload equipment installed in 15 mission-definable spaces. In this photo, the aircraft is shown in flight from below, with the DC-8 silhouetted against a blue sky.

The soluble Decoy Receptor 3 is regulated by a PI3K-dependent mechanism and promotes migration and invasion in renal cell carcinoma.

PubMed

Weissinger, Daniel; Tagscherer, Katrin E; Macher-Göppinger, Stephan; Haferkamp, Axel; Wagener, Nina; Roth, Wilfried

2013-10-10

Overexpression of Decoy Receptor 3 (DcR3), a soluble member of the tumor necrosis factor receptor superfamily, is a common event in several types of cancer. In renal cell carcinoma (RCC), DcR3 overexpression is associated with lymph node and distant metastasis as well as a poor prognosis. However, the functional role and regulation of DcR3 expression in RCC is so far unknown. Modulation of DcR3 expression by siRNA and ectopic gene expression, respectively, was performed in ACHN and 769-P RCC cell lines. Functional effects of a modulated DcR3 expression were analyzed with regard to migration, invasion, adhesion, clonogenicity, and proliferation. Furthermore, quantitative RT-PCR and immunoblot analyses were performed to evaluate the expression of downstream mediators of DcR3. In further experiments, luciferase assays, quantitative RT-PCR and immunoblot analyses were applied to study the regulation of DcR3 expression in RCC. Additionally, an ex vivo tissue slice culture technique combined with immunohistochemistry was used to study the regulation of DcR3 expression in human RCC specimens. Here, we show that DcR3 promotes adhesion, migration and invasiveness of RCC cells. The DcR3-dependent increase in cellular invasiveness is accompanied with an up-regulation of integrin alpha 4, matrixmetalloproteinase 7 and urokinase plasminogen activator (uPA). Further, we identified a signaling pathway regulating DcR3 expression in RCC. Using in vitro experiments as well as an ex vivo RCC tissue slice culture model, we demonstrate that expression of DcR3 is regulated in a PI3K/AKT-dependent manner involving the transcription factor nuclear factor of activated T-cells (NFAT). Taken together, our results identify DcR3 as a key driver of tumor cell dissemination and suggest DcR3 as a promising target for rational therapy of RCC.

Shock Reduction With Antitachycardia Pacing Before and During Charging for Fast Ventricular Tachycardias in Patients With Implantable Defibrillators.

PubMed

Dallaglio, Paolo Domenico; Anguera, Ignasi; Martínez Ferrer, José B; Pérez, Luisa; Viñolas, Xavier; Porres, Jose Manuel; Fontenla, Adolfo; Alzueta, Javier; Martínez, Juan Gabriel; Rodríguez, Aníbal; Basterra, Nuria; Sabaté, Xavier

2017-12-11

Fast ventricular tachycardias in the ventricular fibrillation zone in patients with an implantable cardioverter-defibrillator are susceptible to antitachycardia pacing (ATP) termination. Some manufacturers allow programming 2 ATP bursts: before charging (BC) and during (DC) charging. The aim of this study was to describe the safety and effectiveness of ATP BC and DC for fast ventricular tachycardias in the ventricular fibrillation zone in patients with an implantable cardioverter-defibrillator in daily clinical practice. Data proceeded from the multicenter UMBRELLA trial, including implantable cardioverter-defibrillator patients followed up by the CareLink monitoring system. Fast ventricular tachycardias in the ventricular fibrillation zone until a cycle length of 200ms with ATP BC and/or ATP DC were included. We reviewed 542 episodes in 240 patients. Two ATP bursts (BC/DC) were programmed in 291 episodes (53.7%, 87 patients), while 251 episodes (46.3%, 153 patients) had 1 ATP burst only DC. The number of episodes terminated by 1 ATP DC was 139, representing 55.4% effectiveness (generalized estimating equation-adjusted 60.4%). There were 256 episodes terminated by 1 or 2 ATP (BC/DC), representing 88% effectiveness (generalized estimating equation-adjusted 79.3%); the OR for ATP effectiveness BC/DC vs DC was 2.5, 95%CI, 1.5-4.1; P <.001. Shocked episodes were 112 (45%) for ATP DC vs 35 (12%) for ATP BC/DC, representing an absolute reduction of 73%. The mean shocked episode duration was 16seconds for ATP DC vs 19seconds for ATP BC/DC (P=.07). The ATP DC in the ventricular fibrillation zone for fast ventricular tachycardia is moderately effective. Adding an ATP burst BC increases the overall effectiveness, reduces the need for shocks, and does not prolong episode duration. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Electrical Conductivity, Relaxation and the Glass Transition: A New Look at a Familiar Phenomenon

NASA Technical Reports Server (NTRS)

Angel, Paul W.; Cooper, Alfred R.; DeGuire, Mark R.

1996-01-01

Annealed samples from a single melt of a 10 mol% K2O-90SiO2 glass were reheated to temperatures ranging from 450 to 800 C, held isothermally for 20 min, and then quenched in either air or a silicon oil bath. The complex impedance of both the annealed and quenched samples was measured as a function of temperature from 120 to 250 C using ac impedance spectroscopy from 1 Hz to 1 MHz. The dc conductivity, sigma(sub dc), was measured from the low frequency intercept of depressed semicircle fits to the complex impedance data. When the sigma(sub dc) at 150 C was plotted against soak temperature, the results fell into three separate regions that are explained in terms of the glass structural relaxation time, tau(sub S). This sigma(sub dc) plot provides a new way to look the glass transition range, Delta T(sub r). In addition, sigma(sub dc) was measured for different soak times at 550 C, from which an average relaxation time of 7.3 min was calculated. It was found that the size and position of the Delta T(sub r) is controlled by both the soak time and cooling rate.

Reduced-intensity conditioning for alternative donor hematopoietic stem cell transplantation in patients with dyskeratosis congenita.

PubMed

Nishio, Nobuhiro; Takahashi, Yoshiyuki; Ohashi, Haruhiko; Doisaki, Sayoko; Muramatsu, Hideki; Hama, Asahito; Shimada, Akira; Yagasaki, Hiroshi; Kojima, Seiji

2011-03-01

DC is an inherited bone marrow failure syndrome mainly characterized by nail dystrophy, abnormal skin pigmentation, and oral leukoplakia. Bone marrow failure is the most common cause of death in patients with DC. Because previous results of HSCT with a myeloablative regimen were disappointing, we used a reduced-intensity conditioning regimen for two patients with classic DC, and one patient with cryptic DC who harbored the TERT mutation. Graft sources included two mismatched-related bone marrow (BM) donors and one unrelated BM donor. Successful engraftment was achieved with few regimen-related toxicities in all patients. They were alive 10, 66, and 72 months after transplantation, respectively. Long-term follow-up is crucial to determine the late effects of our conditioning regimen. © 2010 John Wiley & Sons A/S.

[Preparation of electrodeposited Cr-La coating and its spectral properties].

PubMed

Liu, Xiao-zhen; Wang, Gang; Song, Ling-ling; Li, Xin; Zhu, Xu-qiang

2011-07-01

Cr-La coating (dc) and Cr-La coating (pulse) were prepared by electrodeposition method of direct current and pulsating current respectively. The Cr-La coating (dc) and Cr-La coating (pulse) were characterized with ICP-AES, EDAX, XRD and SEM techniques, respectively. Cr-La coating(dc) was amorphous. There were crystalline La and CrC in Cr-La coating (pulse). The microhardness of the Cr-La coating(dc) and Cr-La coating (pulse) were as high as 860.3 and 930.2 HV respectively, which were higher 11.15% and 20.18% higher than that of the Cr coating (774.0 HV). The wear weight losses of Cr-La coating(dc) and Cr-La coating(pulse) were 1.29 and 2.25 times lower than that of Cr coating, respectively. The friction coefficient of Cr coating, Cr-La coating(dc) and Cr-La coating(pulse) were 0. 884, 0. 640 and 0. 648 respectively. The properties of wear weight loss and microhardness of coatings were improved with pulsating current. The wear weight loss and microhardness of Cr-La coating(pulse) were lower 1.75 time lower and higher 8.13% higher than that of the Cr-La coating(dc), respectively.

Powerplexer

NASA Technical Reports Server (NTRS)

Woods, J. M. (Inventor)

1973-01-01

An electrical power distribution system is described for use in providing different dc voltage levels. A circuit is supplied with DC voltage levels and commutates pulses for timed intervals onto a pair of distribution wires. The circuit is driven by a command generator which places pulses on the wires in a timed sequence. The pair of wires extend to voltage strippers connected to the various loads. The voltage strippers each respond to the pulse dc levels on the pair of wires and form different output voltages communicated to each load.

High Power Amplifier and Power Supply

NASA Technical Reports Server (NTRS)

Duong, Johnny; Stride, Scot; Harvey, Wayne; Haque, Inam; Packard, Newton; Ng, Quintin; Ispirian, Julie Y.; Waian, Christopher; Janes, Drew

2008-01-01

A document discusses the creation of a high-voltage power supply (HVPS) that is able to contain voltages up to -20 kV, keep electrical field strengths to below 200 V/mil (approximately equal to 7.87 kV/mm), and can provide a 200-nanosecond rise/fall time focus modulator swinging between cathode potential of 16.3 kV and -19.3 kV. This HVPS can protect the 95-GHz, pulsed extended interaction klystron (EIK) from arcs/discharges from all sources, including those from within the EIK fs vacuum envelope. This innovation has a multi-winding pulse transformer design, which uses new winding techniques to provide the same delays and rise/fall times (less than 10 nanoseconds) at different potential levels ranging from -20 kV to -16 kV. Another feature involves a high-voltage printed-wiring board that was corona-free at -20 kV DC with a 3- kV AC swing. The corona-free multilayer high-voltage board is used to simulate fields of less than 200 V/mil (approximately equal to 7.87 kV/mm) at 20 kV DC. Drive techniques for the modulator FETs (field-effect transistors) (four to 10 in a series) were created to change states (3,000-V swing) without abrupt steps, while still maintaining required delays and transition times. The packing scheme includes a potting mold to house a ten-stage modulator in the space that, in the past, only housed a four-stage modulator. Problems keeping heat down were solved using aluminum oxide substrate in the high-voltage section to limit temperature rise to less than 10 while withstanding -20 kV DC voltage and remaining corona-free.

A very low noise, high accuracy, programmable voltage source for low frequency noise measurements.

PubMed

Scandurra, Graziella; Giusi, Gino; Ciofi, Carmine

2014-04-01

In this paper an approach for designing a programmable, very low noise, high accuracy voltage source for biasing devices under test in low frequency noise measurements is proposed. The core of the system is a supercapacitor based two pole low pass filter used for filtering out the noise produced by a standard DA converter down to 100 mHz with an attenuation in excess of 40 dB. The high leakage current of the supercapacitors, however, introduces large DC errors that need to be compensated in order to obtain high accuracy as well as very low output noise. To this end, a proper circuit topology has been developed that allows to considerably reduce the effect of the supercapacitor leakage current on the DC response of the system while maintaining a very low level of output noise. With a proper design an output noise as low as the equivalent input voltage noise of the OP27 operational amplifier, used as the output buffer of the system, can be obtained with DC accuracies better that 0.05% up to the maximum output of 8 V. The expected performances of the proposed voltage source have been confirmed both by means of SPICE simulations and by means of measurements on actual prototypes. Turn on and stabilization times for the system are of the order of a few hundred seconds. These times are fully compatible with noise measurements down to 100 mHz, since measurement times of the order of several tens of minutes are required in any case in order to reduce the statistical error in the measured spectra down to an acceptable level.

A very low noise, high accuracy, programmable voltage source for low frequency noise measurements

NASA Astrophysics Data System (ADS)

Scandurra, Graziella; Giusi, Gino; Ciofi, Carmine

2014-04-01

In this paper an approach for designing a programmable, very low noise, high accuracy voltage source for biasing devices under test in low frequency noise measurements is proposed. The core of the system is a supercapacitor based two pole low pass filter used for filtering out the noise produced by a standard DA converter down to 100 mHz with an attenuation in excess of 40 dB. The high leakage current of the supercapacitors, however, introduces large DC errors that need to be compensated in order to obtain high accuracy as well as very low output noise. To this end, a proper circuit topology has been developed that allows to considerably reduce the effect of the supercapacitor leakage current on the DC response of the system while maintaining a very low level of output noise. With a proper design an output noise as low as the equivalent input voltage noise of the OP27 operational amplifier, used as the output buffer of the system, can be obtained with DC accuracies better that 0.05% up to the maximum output of 8 V. The expected performances of the proposed voltage source have been confirmed both by means of SPICE simulations and by means of measurements on actual prototypes. Turn on and stabilization times for the system are of the order of a few hundred seconds. These times are fully compatible with noise measurements down to 100 mHz, since measurement times of the order of several tens of minutes are required in any case in order to reduce the statistical error in the measured spectra down to an acceptable level.

Factors influencing early referral, early diagnosis and management in patients with diffuse cutaneous systemic sclerosis.

PubMed

Distler, Oliver; Allanore, Yannick; Denton, Christopher P; Matucci-Cerinic, Marco; Pope, Janet E; Hinzmann, Barbara; Davies, Siobhan; de Oliveira Pena, Janethe; Khanna, Dinesh

2018-05-01

To gain insight into clinical practice regarding referral, early diagnosis and other aspects of the management of patients with dcSSc in Europe and the USA. Semi-structured interviews were conducted with 84 rheumatologists (or internal medicine physicians) and 40 dermatologists in different countries (the UK, France, Germany, Italy, Spain and the USA). Physicians were asked to identify key steps in the patient pathway relating to patient presentation, diagnosis and referral, in addition to other treatment and follow-up processes. The interviewed physicians reported that late presentation with dcSSc was common, with some patients presenting to primary care physicians after symptoms had persisted for up to 1 year. Awareness of dcSSc is reported to vary widely among primary care physicians. Final diagnosis, generally following guideline-based recommendations, was by rheumatologists in most cases (or internal medicine physicians in France) and they remained responsible for global patient management, with lesser involvement in diagnosis and management by dermatologists. Specialist centres were not well defined and did not exist in all countries. Patients and primary healthcare providers can be unaware of the symptoms of dcSSc, therefore presentation and referral to specialist care are often late. Thus, improved awareness among patients and primary care physicians is necessary to facilitate earlier referral and diagnosis. Once referred, more consistent use of the modified Rodnan skin score at diagnosis and follow-up may help to monitor disease progression. Furthermore, establishing specialist centres may help to promote such changes and improve patient care.

GHz laser-free time-resolved transmission electron microscopy: A stroboscopic high-duty-cycle method.

PubMed

Qiu, Jiaqi; Ha, Gwanghui; Jing, Chunguang; Baryshev, Sergey V; Reed, Bryan W; Lau, June W; Zhu, Yimei

2016-02-01

A device and a method for producing ultrashort electron pulses with GHz repetition rates via pulsing an input direct current (dc) electron beam are provided. The device and the method are based on an electromagnetic-mechanical pulser (EMMP) that consists of a series of transverse deflecting cavities and magnetic quadrupoles. The EMMP modulates and chops the incoming dc electron beam and converts it into pico- and sub-pico-second electron pulse sequences (pulse trains) at >1GHz repetition rates, as well as controllably manipulates the resulting pulses. Ultimately, it leads to negligible electron pulse phase-space degradation compared to the incoming dc beam parameters. The temporal pulse length and repetition rate for the EMMP can be continuously tunable over wide ranges. Applying the EMMP to a transmission electron microscope (TEM) with any dc electron source (e.g. thermionic, Schottky, or field-emission source), a GHz stroboscopic high-duty-cycle TEM can be realized. Unlike in many recent developments in time-resolved TEM that rely on a sample pumping laser paired with a laser launching electrons from a photocathode to probe the sample, there is no laser in the presented experimental set-up. This is expected to be a significant relief for electron microscopists who are not familiar with laser systems. The EMMP and the sample are externally driven by a radiofrequency (RF) source synchronized through a delay line. With no laser pumping the sample, the problem of the pump laser induced residual heating/damaging the sample is eliminated. As many RF-driven processes can be cycled indefinitely, sampling rates of 1-50GHz become accessible. Such a GHz stroboscopic TEM would open up a new paradigm for in situ and in operando experiments to study samples externally driven electromagnetically. Complementary to the lower (MHz) repetition rates experiments enabled by laser photocathode TEM, new experiments in the multi-GHz regime will be enabled by the proposed RF design. Because TEM is also a platform for various analytical methods, there are infinite application opportunities in energy and electronics to resolve charge (electronic and ionic) transport, and magnetic, plasmonic and excitonic dynamics in advanced functional materials. In addition, because the beam duty-cycle can be as high as ~10(-1) (or 10%), detection can be accomplished by commercially available detectors. In this article, we report an optimal design of the EMMP. The optimal design was found using an analytical generalized matrix approach in the thin lens approximation along with detailed beam dynamics taking actual realistic dc beam parameters in a TEM operating at 200keV. Copyright © 2015 Elsevier B.V. All rights reserved.

Attention capture by eye of origin singletons even without awareness--a hallmark of a bottom-up saliency map in the primary visual cortex.

PubMed

Zhaoping, Li

2008-05-07

Human observers are typically unaware of the eye of origin of visual inputs. This study shows that an eye of origin or ocular singleton, e.g., an item in the left eye among background items in the right eye, can nevertheless attract attention automatically. Observers searched for a uniquely oriented bar, i.e., an orientation singleton, in a background of horizontal bars. Their reports of the tilt direction of the search target in a brief (200 ms) display were more accurate in a dichoptic congruent (DC) condition, when the target was also an ocular singleton, than in a monocular (M) condition, when all bars were presented to the same single eye, or a dichoptic incongruent (DI) condition, when an ocular singleton was a background bar. The better performance in DC did not depend on the ability of the observers to report the presence of an ocular singleton by making forced choices in the same stimuli (though without the orientation singleton). This suggests that the ocular singleton exogenously cued attention to its location, facilitating the identification of the tilt singleton in the DC condition. When the search display persisted without being masked, observers' reaction times (RTs) for reporting the location of the search target were shorter in the DC, and longer in the DI, than the M condition, regardless of whether the observers were aware that different conditions existed. In an analogous design, similar RT patterns were observed for the task of finding an orientation contrast texture border. These results suggest that in typical trials, attention was more quickly attracted to or initially distracted from the target in the DC or DI condition, respectively. Hence, an ocular singleton, though elusive to awareness, can effectively compete for attention with an orientation singleton (tilted 20 or 50 degrees from background bars in the current study). Similarly, it can also make a difficult visual search easier by diminishing the set size effect. Since monocular neurons with the eye of origin information are abundant in the primary visual cortex (V1) and scarce in other cortical areas, and since visual awareness is believed to be absent or weaker in V1 than in other cortical areas, our results provide a hallmark of the role of V1 in creating a bottom-up saliency map to guide attentional selection.

Sterilization by negative and positive DC plasma with a micro discharge gap at atmospheric pressure

NASA Astrophysics Data System (ADS)

Li, Hua; Jiang, Lin-Xiu; Jiang, Yong-Rong; Zhu, Jian-Min; Chen, Zhen-Cheng

2017-11-01

A new needle-to-droplet electrode structure with a micro discharge gap (2 mm) was designed to achieve direct current (DC) discharge plasma in ambient air with the aim of using the plasma to sterilize liquids. Without using noble gases or an external air flow, we succeeded in generating both a negative and positive DC plasma at atmospheric pressure. The plasma was driven by a 0 to -20,000 V, 100 W DC power supply. A stainless steel needle with a tip diameter of ˜ 50μm and a 200-μL droplet of bacteria-containing liquid served as the electrodes. At atmospheric pressure and room temperature (23∘C), utilizing the negative DC plasma, the discharge time lasted 10 s; the results showed that the higher the discharge voltage, the more efficient the sterilization effect. Conversely, when we applied a voltage of -5.5 kV, we found that the sterilization effect was more efficient for longer discharge times. Our findings demonstrate that Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) can be killed in about 30 s. Our experiments show that our sterilization method required less time and was more efficient for positive than for negative DC plasma under the same conditions.

Adaptation of a 3-D Quadrupole Ion Trap for Dipolar DC Collisional Activation

PubMed Central

Prentice, Boone M.; Santini, Robert E.; McLuckey, Scott A.

2011-01-01

Means to allow for the application of a dipolar DC pulse to the end-cap electrodes of a three-dimensional (3-D) quadrupole ion trap for as short as a millisecond to as long as hundreds of milliseconds are described. The implementation of dipolar DC does not compromise the ability to apply AC waveforms to the end-cap electrodes at other times in the experiment. Dipolar DC provides a nonresonant means for ion acceleration by displacing ions from the center of the ion trap where they experience stronger rf electric fields, which increases the extent of micro-motion. The evolution of the product ion spectrum to higher generation products with time, as shown using protonated leucine enkephalin as a model protonated peptide, illustrates the broad-band nature of the activation. Dipolar DC activation is also shown to be effective as an ion heating approach in mimicking high amplitude short time excitation (HASTE)/pulsed Q dissociation (PQD) resonance excitation experiments that are intended to enhance the likelihood for observing low m/z products in ion trap tandem mass spectrometry. PMID:21953251

Loss of Pace Capture on the Ablation Line During Pulmonary Vein Isolation versus "Dormant Conduction": Is Adenosine Expendable?

PubMed

Schaeffer, Benjamin; Willems, Stephan; Sultan, Arian; Hoffmann, Boris A; Lüker, Jakob; Schreiber, Doreen; Akbulak, Ruken; Moser, Julia; Kuklik, Pawel; Steven, Daniel

2015-10-01

Permanent pulmonary vein isolation (PVI) remains an essential goal of ablation therapy in patients with atrial fibrillation. Aim of this study was the intraindividual comparison of unexcitability to pacing along the ablation line versus dormant conduction (DC) as additional procedural endpoints. A total of 58 patients with paroxysmal atrial fibrillation (PAF) underwent PVI by circumferential ablation of ipsilateral pulmonary veins (PVs), followed by testing for DC by adenosine administration. Irrespective of the presence of DC, pacing along the ablation line for left atrium capture was performed and additional radio frequency energy applied if necessary. PVs with initial DC were retested after achieving unexcitability. PVI was achieved in 224 of 224 PVs. In 33 of 224 PVs (15%) DC was revealed. At 92 of 112 ablation lines (82%) sites of excitability were found. Three (9%) of the initial 33 PVs with DC showed further DC after achieving unexcitability at repeated testing. Thirty-two of 33 assumed areas of unmasked PV-LA reconduction as revealed by DC-testing showed a corresponding site of excitability on the ablation line. After a follow-up of 11.6 ± 3.4 months 79% of patients were free of arrhythmia. Pacing for unexcitability can safely identify potential sites of DC and even sites that would have not been detected by testing for DC. Unexcitability, therefore, serves as a suitable and safe procedural endpoint not only for patients with contraindications to adenosine administration. Our data suggest that adenosine may be expendable when achieving unexcitability along the ablation line. © 2015 Wiley Periodicals, Inc.

EGFR-driven up-regulation of decoy receptor 3 in keratinocytes contributes to the pathogenesis of psoriasis.

PubMed

Wu, Nan-Lin; Huang, Duen-Yi; Hsieh, Shie-Liang; Hsiao, Cheng-Hsiang; Lee, Te-An; Lin, Wan-Wan

2013-10-01

Decoy receptor 3 (DcR3) is a soluble receptor of Fas ligand (FasL), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A) and plays pleiotropic roles in many inflammatory and autoimmune disorders and malignant diseases. In cutaneous biology, DcR3 is expressed in primary human epidermal keratinocytes and is upregulated in skin lesions in psoriasis, which is characterized by chronic inflammation and angiogenesis. However, the regulatory mechanisms of DcR3 over-expression in skin lesions of psoriasis are unknown. Here, we demonstrate that DcR3 can be detected in both dermal blood vessels and epidermal layers of psoriatic skin lesions. Analysis of serum samples showed that DcR3 was elevated, but FasL was downregulated in psoriatic patients compared with normal individuals. Additional cell studies revealed a central role of epidermal growth factor receptor (EGFR) in controlling the basal expression of DcR3 in keratinocytes. Activation of EGFR by epidermal growth factor (EGF) and transforming growth factor (TGF)-α strikingly upregulated DcR3 production. TNF-αenhanced DcR3 expression in both keratinocytes and endothelial cells compared with various inflammatory cytokines involved in psoriasis. Additionally, TNF-α-enhanced DcR3 expression in keratinocytes was inhibited when EGFR was knocked down or EGFR inhibitor was used. The NF-κB pathway was critically involved in the molecular mechanisms underlying the action of EGFR and inflammatory cytokines. Collectively, the novel regulatory mechanisms of DcR3 expression in psoriasis, particularly in keratinocytes and endothelial cells, provides new insight into the pathogenesis of psoriasis and may also contribute to the understanding of other diseases that involve DcR3 overexpression. Copyright © 2013 Elsevier B.V. All rights reserved.

Dendritic cells' death induced by contact sensitizers is controlled by Nrf2 and depends on glutathione levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

El Ali, Zeina

Dendritic cells (DC) are known to play a major role during contact allergy induced by contact sensitizers (CS). Our previous studies showed that Nrf2 was induced in DC and controlled allergic skin inflammation in mice in response to chemicals. In this work, we raised the question of the role of Nrf2 in response to a stress provoked by chemical sensitizers in DC. We used two well-described chemical sensitizers, dinitrochlorobenzene (DNCB) and cinnamaldehyde (CinA), known to have different chemical reactivity and mechanism of action. First, we performed a RT-qPCR array showing that CinA was a higher inducer of immune and detoxificationmore » genes compared to DNCB. Interestingly, in the absence of Nrf2, gene expression was dramatically affected in response to DNCB but was slightly affected in response to CinA. These observations prompted us to study DC's cell death in response to both chemicals. DNCB and CinA increased apoptotic cells and decreased living cells in the absence of Nrf2. The characterization of DC apoptosis induced by both CS involved the mitochondrial-dependent caspase pathway and was regulated via Nrf2 in response to both chemicals. Oxidative stress induced by DNCB, and leading to cell death, was regulated by Nrf2. Unlike CinA, DNCB treatment provoked a significant reduction of intracellular GSH levels and up-regulated bcl-2 gene expression, under the control of Nrf2. This work underlies that chemical reactivity may control Nrf2-dependent gene expression leading to different cytoprotective mechanisms in DC. - Highlights: • Nrf2 controls cell death induced by contact sensitizers in dendritic cells. • DNCB reduced GSH levels and up-regulated bcl-2 gene expression unlike CinA. • Chemical reactivity controls Nrf2-dependent genes having protective effect in DC.« less

Outcomes of single- vs double-cuff artificial urinary sphincter insertion in low- and high-risk profile male patients with severe stress urinary incontinence.

PubMed

Ahyai, Sascha A; Ludwig, Tim A; Dahlem, Roland; Soave, Armin; Rosenbaum, Clemens; Chun, Felix K-H; Fisch, Margit; Schmid, Marianne; Kluth, Luis A

2016-10-01

To evaluate continence and complication rates of bulbar single-cuff (SC) and distal bulbar double-cuff (DC) insertion in male patients with severe stress urinary incontinence (SUI) according to whether the men were considered low or high risk for unfavourable artificial urinary sphincter (AUS) outcomes. In all, 180 male patients who underwent AUS implantation between 2009 and 2013 were followed according to institutional standards. Patients with previous pelvic radiation therapy, open bulbar urethral or UI surgery ('high risk') underwent distal bulbar DC (123 patients) insertion, all others ('low risk') had proximal bulbar SC (57) insertion. Primary and secondary endpoints consisted of continence and complication rates. Kaplan-Meier analysis determined explantation-free survival, and Cox regression models assessed risk factors for persistent UI and explantation. The median follow-up was 24 months. Whereas there was no significant difference in pad usage/objective continence after SC vs DC insertion, superior rates of subjective/social continence and less persistent UI were reported by the patients with DC devices (all P ≤ 0.02). Overall, device explantation (erosion, infection or mechanical failure) occurred in 12.8% of patients. While early (<6 weeks) complication rates compared with SC patients were similar (P > 0.05), DC patients had a 5.7-fold higher risk of device explantation during late follow-up (P = 0.02) and significantly shorter explantation-free survival (log-rank, P = 0.003). Distal bulbar DC insertion in patients with a 'high-risk' profile (previous pelvic radiation, urethral surgery) leads to similar objective continence, but higher explantation rates when compared with patients considered 'low risk' with proximal bulbar SCs. Randomised controlled trials comparing both devices will be needed to determine whether the higher explanations rates are attributable to the DC device or to underlying risk factors. © 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.

DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

NASA Astrophysics Data System (ADS)

Nikam, Pravin N.; Deshpande, Vineeta D.

2016-05-01

Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al2O3) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σAC) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher's universal power law of solids. It revealed that σAC of PET/alumina nanocomposites can be well characterized by the DC conductivity (σDC), critical frequency (ωc), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σDC) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

Megawatt low-temperature DC plasma generator with divergent channels of gas-discharge tract

NASA Astrophysics Data System (ADS)

Gadzhiev, M. Kh.; Isakaev, E. Kh.; Tyuftyaev, A. S.; Yusupov, D. I.; Sargsyan, M. A.

2017-04-01

We have developed and studied a new effective megawatt double-unit generator of low-temperature argon plasma, which belongs to the class of dc plasmatrons and comprises the cathode and anode units with divergent gas-discharge channels. The generator has an efficiency of about 80-85% and ensures a long working life at operating currents up to 4000 A.

A Plan for Evaluating the District of Columbia's Public Schools: From Impressions to Evidence

ERIC Educational Resources Information Center

National Academies Press, 2011

2011-01-01

The District of Columbia (DC) has struggled for decades to improve its public education system. In 2007 the DC government made a bold change in the way it governs public education with the goal of shaking up the system and bringing new energy to efforts to improve outcomes for students. The Public Education Reform Amendment Act (PERAA) shifted…

The experimental study of the DC dielectric breakdown strength in magnetic fluids

NASA Astrophysics Data System (ADS)

Kopčanský, P.; Tomčo, L.; Marton, K.; Koneracká, M.; Potočová, I.; Timko, M.

2004-05-01

Magnetic fluids have been studied for use as a high-voltage insulation. High-voltage measurements on magnetic fluids based on transformer oil, as a function of volume concentrations of magnetite particles and applied magnetic field, showed the increase of the DC dielectric breakdown strength opposite transformer oil, if the saturation magnetization of magnetic fluid is up to 4 mT approximately.

Application of 1H and 23Na magic angle spinning NMR spectroscopy to define the HRBC up-taking of MRI contrast agents

NASA Astrophysics Data System (ADS)

Calabi, Luisella; Paleari, Lino; Biondi, Luca; Linati, Laura; De Miranda, Mario; Ghelli, Stefano

2003-09-01

The up-take of Gd(III) complexes of BOPTA, DTPA, DOTA, EDTP, HPDO3A, and DOTP in HRBC has been evaluated by measuring the lanthanide induced shift (LIS) produced by the corresponding dysprosium complexes (DC) on the MAS-NMR resonances of water protons and free sodium ions. These complexes are important in their use as MRI contrast agents (MRI-CA) in diagnostics. 1H and 23Na MAS-NMR spectra of HRBC suspension, collected at 9.395 T, show only one signal due to extra- and intra-cellular water (or sodium). In MAS spectra, the presence of DC in a cellular compartment produces the LIS of only the nuclei (water proton or sodium) in that cellular compartment and this LIS can be related to the DC concentrations (by the experimental curves of LIS vs. DC concentrations) collected in the physiological solution. To obtain correct results about LIS, the use of MAS technique is mandatory, because it guarantees the only the nuclei staying in the same cellular compartment where the LC is present show the LIS. In all the cases considered, the addition of the DC to HRBC (100% hematocrit) produced a shift of only the extra-cellular water (or sodium) signal and the gradient of concentration ( GC) between extra- and intra-cellular compartments resulted greater than 100:1, when calculated by means of sodium signals. These high values of GC are direct proofs that none of the tested dysprosium complexes crosses the HRBC membrane. Since the DC are iso-structural to the gadolinium complexes the corresponding gadolinium ones (MRI-CA) do not cross the HRBC membrane and, consequently, they are not up-taken in HRBC. The GC values calculated by means of water proton signals resulted much lower than those obtained by sodium signals. This proves that the choice of the isotope is a crucial step in order to use this method in the best way. In fact, GC value depends on the lowest detectable LIS which, in turn, depends on the nature of the LC (lanthanide complex) and the observed isotopes.

Heavy rainfall in Mediterranean cyclones. Part I: contribution of deep convection and warm conveyor belt

NASA Astrophysics Data System (ADS)

Flaounas, Emmanouil; Kotroni, Vassiliki; Lagouvardos, Konstantinos; Gray, Suzanne L.; Rysman, Jean-François; Claud, Chantal

2018-04-01

In this study, we provide an insight to the role of deep convection (DC) and the warm conveyor belt (WCB) as leading processes to Mediterranean cyclones' heavy rainfall. To this end, we use reanalysis data, lighting and satellite observations to quantify the relative contribution of DC and the WCB to cyclone rainfall, as well as to analyse the spatial and temporal variability of these processes with respect to the cyclone centre and life cycle. Results for the period 2005-2015 show that the relationship between cyclone rainfall and intensity has high variability and demonstrate that even intense cyclones may produce low rainfall amounts. However, when considering rainfall averages for cyclone intensity bins, a linear relationship was found. We focus on the 500 most intense tracked cyclones (responsible for about 40-50% of the total 11-year Mediterranean rainfall) and distinguish between the ones producing high and low rainfall amounts. DC and the WCB are found to be the main cause of rainfall for the former (producing up to 70% of cyclone rainfall), while, for the latter, DC and the WCB play a secondary role (producing up to 50% of rainfall). Further analysis showed that rainfall due to DC tends to occur close to the cyclones' centre and to their eastern sides, while the WCBs tend to produce rainfall towards the northeast. In fact, about 30% of rainfall produced by DC overlaps with rainfall produced by WCBs but this represents only about 8% of rainfall produced by WCBs. This suggests that a considerable percentage of DC is associated with embedded convection in WCBs. Finally, DC was found to be able to produce higher rain rates than WCBs, exceeding 50 mm in 3-h accumulated rainfall compared to a maximum of the order of 40 mm for WCBs. Our results demonstrate in a climatological framework the relationship between cyclone intensity and processes that lead to heavy rainfall, one of the most prominent environmental risks in the Mediterranean. Therefore, we set perspectives for a deeper analysis of the favourable atmospheric conditions that yield high impact weather.

Effects of treatment time and temperature on the DC corona pretreatment performance of waste activated sludge

NASA Astrophysics Data System (ADS)

Yu, GAO; Ning, ZHAO; Yongdi, DENG; Minghang, WANG; Boxue, DU

2018-02-01

In order to improve the anaerobic digestion efficiency of waste activated sludge (WAS), a pretreatment procedure should be carried out so as to disrupt the microbial cell structure, thus releasing intracellular organic matters. In this paper, a corona discharge triggered by a DC voltage was employed to pre-treat WAS for various time periods under different temperatures. The magnitude of the DC voltage was 4 kV at both negative and positive polarities. The changes in the soluble chemical oxygen demand, phosphorus and nitrogen content, and pH value within the WAS were utilized to estimate the pretreatment performance of the DC corona. It was found that with increasing treatment time, the pretreatment efficiency tends to be reduced. With increased temperature, the pretreatment efficiency appears to be better. It is suggested that the oxidative species and the active particles generated in the corona discharge play an important role in disrupting the microbial cell structure, which is dependent upon the treatment time and the temperature.

Design of a -1 MV dc UHV power supply for ITER NBI

NASA Astrophysics Data System (ADS)

Watanabe, K.; Yamamoto, M.; Takemoto, J.; Yamashita, Y.; Dairaku, M.; Kashiwagi, M.; Taniguchi, M.; Tobari, H.; Umeda, N.; Sakamoto, K.; Inoue, T.

2009-05-01

Procurement of a dc -1 MV power supply system for the ITER neutral beam injector (NBI) is shared by Japan and the EU. The Japan Atomic Energy Agency as the Japan Domestic Agency (JADA) for ITER contributes to the procurement of dc -1 MV ultra-high voltage (UHV) components such as a dc -1 MV generator, a transmission line and a -1 MV insulating transformer for the ITER NBI power supply. The inverter frequency of 150 Hz in the -1 MV power supply and major circuit parameters have been proposed and adopted in the ITER NBI. The dc UHV insulation has been carefully designed since dc long pulse insulation is quite different from conventional ac insulation or dc short pulse systems. A multi-layer insulation structure of the transformer for a long pulse up to 3600 s has been designed with electric field simulation. Based on the simulation the overall dimensions of the dc UHV components have been finalized. A surge energy suppression system is also essential to protect the accelerator from electric breakdowns. The JADA contributes to provide an effective surge suppression system composed of core snubbers and resistors. Input energy into the accelerator from the power supply can be reduced to about 20 J, which satisfies the design criteria of 50 J in total in the case of breakdown at -1 MV.

NASA DC-8 airborne research laboratory

NASA Technical Reports Server (NTRS)

Degreef, Leo H.

1991-01-01

Since the summer of 1987, NASA Ames Research Center has been operating a DC-8 equipped with CFM 56 engines as a flying research laboratory. In this relatively short time, the DC-8, with its tremendous capabilities, has made significant contributions to numerous scientific fields. Capable of staying aloft for over 12 hours, the DC-8 has flown directly over both the North and South Poles, gathering data relating to the ozone hole. Operating from a few thousand feet to over 40,000 feet above sea level the interchangeable payload capability of the DC-8 has made it a versatile scientific tool. The DC-8 also plays a vital role in the development of new satellite-borne sensors as very often those sensors are test-flown on the DC-8 before they are launched into space. The tremendous range and instrument carrying capability make the DC-8 an ideal flying laboratory. A few of the programs the DC-8 has participated in as well as a sampling of the instruments carried are outlined.

Differential Depletion Capacitance Approximation Analysis Under DC Voltage for Air-Exposed Cu/n-Si Schottky Diodes

NASA Astrophysics Data System (ADS)

Korkut, A.

It is well known that the semiconductor surface is easily oxidized by air-media in time. This work studieds the characterization of Schottky diodes and changes in depletion capacitance, which is caused by air exposure of a group of Cu/n-Si/Al Schottky diodes. First, data for current-voltage and capacitance-voltage were a Ren, and then ideality factor, barrier height, built-in potential (Vbi), donor concentration and Fermi level, interfacial oxide thickness, interface state density were calculated. It is seen that depletion capacitance was calculate; whereafter built-in potential played an important role in Schottky diodes characteristic. Built-in potential directly affects the characteristic of Schottky diodes and a turning point occurs. In case of forward and reverse bias, depletion capacitance versus voltage graphics are matched, but in an opposite direction. In case of forward bias, differential depletion capacitance begins from minus values, it is raised to first Vbi, then reduced to second Vbi under the minus condition. And it sharply gones up to positive apex, then sharply falls down to near zero, but it takes positive values depending on DC voltage. In case of reverse bias, differential depletion capacitance takes to small positive values. In other respects, we see that depletion characteristics change considerably under DC voltage.

Development, Demonstration, and Control of a Testbed for Multiterminal HVDC System

DOE PAGES

Li, Yalong; Shi, Xiaojie M.; Liu, Bo; ...

2016-10-21

This paper presents the development of a scaled four-terminal high-voltage direct current (HVDC) testbed, including hardware structure, communication architecture, and different control schemes. The developed testbed is capable of emulating typical operation scenarios including system start-up, power variation, line contingency, and converter station failure. Some unique scenarios are also developed and demonstrated, such as online control mode transition and station re-commission. In particular, a dc line current control is proposed, through the regulation of a converter station at one terminal. By controlling a dc line current to zero, the transmission line can be opened by using relatively low-cost HVDC disconnectsmore » with low current interrupting capability, instead of the more expensive dc circuit breaker. Utilizing the dc line current control, an automatic line current limiting scheme is developed. As a result, when a dc line is overloaded, the line current control will be automatically activated to regulate current within the allowable maximum value.« less

Electroluminescence of hot electrons in AlGaN/GaN high-electron-mobility transistors under radio frequency operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brazzini, Tommaso, E-mail: tommaso.brazzini@bristol.ac.uk; Sun, Huarui; Uren, Michael J.

2015-05-25

Hot electrons in AlGaN/GaN high electron mobility transistors are studied during radio frequency (RF) and DC operation by means of electroluminescence (EL) microscopy and spectroscopy. The measured EL intensity is decreased under RF operation compared to DC at the same average current, indicating a lower hot electron density. This is explained by averaging the DC EL intensity over the measured load line used in RF measurements, giving reasonable agreement. In addition, the hot electron temperature is lower by up to 15% under RF compared to DC, again at least partially explainable by the weighted averaging along the specific load line.more » However, peak electron temperature under RF occurs at high V{sub DS} and low I{sub DS} where EL is insignificant suggesting that any wear-out differences between RF and DC stress of the devices will depend on the balance between hot-carrier and field driven degradation mechanisms.« less

75 FR 35122 - Announcement of Meetings of the International Telecommunication Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-21

.... Eastern Daylight Time, at 1120 20th Street, Washington, DC 20036. There will also be reports on recent... Conference). For those people outside the Washington, DC metro area, a conference bridge will be provided... 1200 Wilson Boulevard, Arlington, VA 22209. For those people outside the Washington, DC metro area, a...

The Proving Grounds: School "Rheeform" in Washington, D.C.

ERIC Educational Resources Information Center

Dingerson, Leigh

2010-01-01

Washington, D.C., is leading the transformation of urban public education across the country--at least according to "Time" magazine, which featured D.C. Schools Chancellor Michelle Rhee on its cover, wearing black and holding a broom. But there is nothing remarkably visionary going on in Washington. The model of school reform that is…

Volatility measurement with directional change in Chinese stock market: Statistical property and investment strategy

NASA Astrophysics Data System (ADS)

Ma, Junjun; Xiong, Xiong; He, Feng; Zhang, Wei

2017-04-01

The stock price fluctuation is studied in this paper with intrinsic time perspective. The event, directional change (DC) or overshoot, are considered as time scale of price time series. With this directional change law, its corresponding statistical properties and parameter estimation is tested in Chinese stock market. Furthermore, a directional change trading strategy is proposed for invest in the market portfolio in Chinese stock market, and both in-sample and out-of-sample performance are compared among the different method of model parameter estimation. We conclude that DC method can capture important fluctuations in Chinese stock market and gain profit due to the statistical property that average upturn overshoot size is bigger than average downturn directional change size. The optimal parameter of DC method is not fixed and we obtained 1.8% annual excess return with this DC-based trading strategy.

Improved hemodynamic parameters in middle cerebral artery infarction after decompressive craniectomy.

PubMed

Amorim, Robson Luis; de Andrade, Almir Ferreira; Gattás, Gabriel S; Paiva, Wellingson Silva; Menezes, Marcos; Teixeira, Manoel Jacobsen; Bor-Seng-Shu, Edson

2014-05-01

Decompressive craniectomy (DC) reduces mortality and improves functional outcome in patients with malignant middle cerebral artery infarction. However, little is known regarding the impact of DC on cerebral hemodynamics. Therefore, our goal was to study the hemodynamic changes that may occur in patients with malignant middle cerebral artery infarction after DC and to assess their relationship with outcomes. Twenty-seven patients with malignant middle cerebral artery infarction who were treated with DC were studied. The perfusion CT hemodynamic parameters, mean transit time, cerebral blood flow, and cerebral blood volume were evaluated preoperatively and within the first 24 hours after DC. There was a global trend toward improved cerebral hemodynamics after DC. Preoperative and postoperative absolute mean transit times were associated with mortality at 6 months, and the ratio of post- and preoperative cerebral blood flow was significantly higher in patients with favorable outcomes than those with unfavorable outcomes. Patients who underwent surgery 48 hours after stroke, those with midline brain shift>10 mm, and those who were >55 years showed no significant improvement in any perfusion CT parameters. DC improves cerebral hemodynamics in patients with malignant middle cerebral artery infarction, and the level of improvement is related to outcome. However, some patients did not seem to experience any additional hemodynamic benefit, suggesting that perfusion CT may play a role as a prognostic tool in patients undergoing DC after ischemic stroke.

Hot electron generation under large-signal radio frequency operation of GaN high-electron-mobility transistors

NASA Astrophysics Data System (ADS)

Latorre-Rey, Alvaro D.; Sabatti, Flavio F. M.; Albrecht, John D.; Saraniti, Marco

2017-07-01

In order to assess the underlying physical mechanisms of hot carrier-related degradation such as defect generation in millimeter-wave GaN power amplifiers, we have simulated the electron energy distribution function under large-signal radio frequency conditions in AlGaN/GaN high-electron-mobility transistors. Our results are obtained through a full band Monte Carlo particle-based simulator self-consistently coupled to a harmonic balance circuit solver. At lower frequency, simulations of a Class AB power amplifier at 10 GHz show that the peak hot electron generation is up to 43% lower under RF drive than it is under DC conditions, regardless of the input power or temperature of operation. However, at millimeter-wave operation up to 40 GHz, RF hot carrier generation reaches that from DC biasing and even exceeds it up to 75% as the amplifier is driven into compression. Increasing the temperature of operation also shows that degradation of DC and RF characteristics are tightly correlated and mainly caused by increased phonon scattering. The accurate determination of the electron energy mapping is demonstrated to be a powerful tool for the extraction of compact models used in lifetime and reliability analysis.

Dendritic cells regulate angiogenesis associated with liver fibrogenesis.

PubMed

Blois, Sandra M; Piccioni, Flavia; Freitag, Nancy; Tirado-González, Irene; Moschansky, Petra; Lloyd, Rodrigo; Hensel-Wiegel, Karin; Rose, Matthias; Garcia, Mariana G; Alaniz, Laura D; Mazzolini, Guillermo

2014-01-01

During liver fibrogenesis the immune response and angiogenesis process are fine-tuned resulting in activation of hepatic stellate cells that produce an excess of extracellular matrix proteins. Dendritic cells (DC) play a central role modulating the liver immunity and have recently been implicated to favour fibrosis regression; although their ability to influence the development of fibrogenesis is unknown. Therefore, we explored whether the depletion of DC during early stages of liver injury has an impact in the development of fibrogenesis. Using the CD11c.DTR transgenic mice, DC were depleted in two experimental models of fibrosis in vivo. The effect of anti-angiogenic therapy was tested during early stages of liver fibrogenesis. DC depletion accelerates the development of fibrosis and as a consequence, the angiogenesis process is boosted. We observed up-regulation of pro-angiogenic factors together with an enhanced vascular endothelial growth factor (VEGF) bioavailability, mainly evidenced by the decrease of anti-angiogenic VEGF receptor 1 (also known as sFlt-1) levels. Interestingly, fibrogenesis process enhanced the expression of Flt-1 on hepatic DC and administration of sFlt-1 was sufficient to abrogate the acceleration of fibrogenesis upon DC depletion. Thus, DC emerge as novel players during the development of liver fibrosis regulating the angiogenesis process and thereby influencing fibrogenesis.

Human platelet lysate is a successful alternative serum supplement for propagation of monocyte-derived dendritic cells.

PubMed

Švajger, Urban

2017-04-01

Clinical protocols for dendritic cell (DC) generation from monocytes require the use of animal serum-free supplements. Serum-free media can also require up to 1% of serum supplementation. In addition, recommendations based on the 3Rs (Refinement, Reduction, Replacement) principle also recommend the use of non-animal sera in in vitro studies. The aim of this study was to explore the potential use of platelet lysate (PL) for generation of optimally differentiated DCs from monocytes. Cells were isolated from buffy coats from healthy volunteers using immunomagnetic selection. DCs were differentiated in RPMI1640 supplemented with either 10% fetal bovine serum (FBS), 10% AB serum or 10% PL with the addition of granulocyte monocyte colony stimulating factor and interleukin-4. Generated DCs were assessed for their morphology, viability, endocytotic capacity, surface phenotype (immature, mature and tolerogenic DCs) and activation of important signaling pathways. DC function was evaluated on the basis of their allostimulatory capacity, cytokine profile and ability to induce different T-helper subsets. DCs generated with PL displayed normal viability, morphology and endocytotic capacity. Their differentiation and maturation phenotype was comparable to FBS-cultured DCs. They showed functional plasticity and up-regulated tolerogenic markers in response to their environment. PL-cultured mature DCs displayed unhindered allostimulatory potential and the capacity to induce Th1 responses. The use of PL allowed for activation of crucial signaling proteins associated with DC differentiation and maturation. This study demonstrates for the first time that human PL represents a successful alternative to FBS in differentiation of DCs from monocytes. DCs display the major phenotypic and functional characteristics compared with existing culture protocols. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Skid Prevention for EVs Based on the Emulation of Torque Reduction Characteristics of Separately-excited DC Motor

NASA Astrophysics Data System (ADS)

Kodama, Shinya; Hori, Yoichi

It is well-known that the separately-excited DC motor has effective torque (current) reduction characteristics in response to rapid increase in the rotational speed of the motor. These characteristics have been utilized in adhesion control of electric railway trains with separately-excited DC motor. Up to now, we have proposed a new skid prevention method for EVs, utilizing these characteristics and have made experiments with the hardware skid simulator “Motor-Generator setup”. In this paper, we applied this skid prevention control to our new vehicle “UOT CADWELL EV" equipped with BLDC motors and showed its effectiveness.

Qualitative Features Extraction from Sensor Data using Short-time Fourier Transform

NASA Technical Reports Server (NTRS)

Amini, Abolfazl M.; Figueroa, Fernando

2004-01-01

The information gathered from sensors is used to determine the health of a sensor. Once a normal mode of operation is established any deviation from the normal behavior indicates a change. This change may be due to a malfunction of the sensor(s) or the system (or process). The step-up and step-down features, as well as sensor disturbances are assumed to be exponential. An RC network is used to model the main process, which is defined by a step-up (charging), drift, and step-down (discharging). The sensor disturbances and spike are added while the system is in drift. The system runs for a period of at least three time-constants of the main process every time a process feature occurs (e.g. step change). The Short-Time Fourier Transform of the Signal is taken using the Hamming window. Three window widths are used. The DC value is removed from the windowed data prior to taking the FFT. The resulting three dimensional spectral plots provide good time frequency resolution. The results indicate distinct shapes corresponding to each process.

Comparison of control structures for a bidirectional high-frequency dc-dc converter

NASA Astrophysics Data System (ADS)

Himmelstoss, Felix A.; Kolar, Johann W.; Zach, Franz C.

1989-08-01

A system for dc-dc power conversion based on a buck-boost converter topology is presented. It makes power flow in both directions possible. The possibility of bidirectional power flow is useful for certain applications, such as uninterruptable power supplies. Starting from a structural diagram the transfer function of the system is derived. The controller for the converter is then designed. It is made up of a simple voltage controller, a voltage controller with an inner loop current controller (cascade control) and with two kinds of state space control. The transfer functions of the different system parts are derived and dimensioning guidelines for the controller sections are presented. The closed loop behavior of the bidirectional converter for the different control structures is analyzed based on simulation using duty cycle averaging. Bodediagrams and step responses are shown.

Solar fed DC-DC single ended primary inductance converter for low power applications

NASA Astrophysics Data System (ADS)

Narendranath, K. V.; Viswanath, Y.; Babu, K. Suresh; Arunkumar, G.; Elangovan, D.

2017-11-01

This paper presents 34 to 36 volts. SEPIC converter for solar fed applications. Now days, there has been tremendous increase in the usage of solar energy and this solar energy is most valuable energy source available all around the world. The solar energy system require a Dc-Dc converter in order to modulate and govern the changing output of the panel. In this paper, a system comprising of Single Ended Primary Inductance Converter [SEPIC] integrated with solar panel is proposed. This paper proposes SEPIC power converter design that will secure high performance and cost efficiency while powering up a LAMP load. This power converter designed with low output ripple voltage, higher efficiency and less electrical pressure on the power switching elements. The simulation and prototype hardware results are presented in this paper.

Development of ATC for High Speed and High Density Commuter Line

NASA Astrophysics Data System (ADS)

Okutani, Tamio; Nakamura, Nobuyuki; Araki, Hisato; Irie, Shouji; Osa, Hiroki; Sano, Minoru; Ikeda, Keigo; Ozawa, Hiroyuki

A new ATC (Automatic Train Control) system has been developed with solutions to realize short train headway by assured braking utilizing digital data transmission via rails; the digital data for the ATP (Automatic Train Protection) function; and to achieve EMC features for both AC and DC sections. The DC section is of the unprecedented DC traction power supply system utilizing IGBT PWM converter at all DC substations. Within the AC section, train traction force is controlled by PWM converter/inverters. The carrier frequencies of the digital data signals and chopping frequency of PWM traction power converters on-board are decided via spectral analysis of noise up to degraded mode cases of equipment. Developed system was equipped to the Tukuba Express Line, new commuter line of Tokyo metropolitan area, and opened since Aug. 2005.

Effects of dendritic cell-activated and cytokine-induced killer cell therapy on 22 children with acute myeloid leukemia after chemotherapy.

PubMed

Bai, Yan; Zheng, Jin-e; Wang, Nan; Cai, He-hua; Zhai, Li-na; Wu, Yao-hui; Wang, Fang; Jin, Run-ming; Zhou, Dong-feng

2015-10-01

The efficiency of dendritic cell-activated and cytokine-induced killer cell (DC-CIK) therapy on children with acute myeloid leukemia (AML) after chemotherapy was investigated. Mononuclear cells were collected from children achieving complete remission after chemotherapy, cultured in vitro and transfused back into the same patient. Interleukin-2 (IL-2) was injected subcutaneously every other day 10 times at the dose of 1 × 10(6) units. Peripheral blood lymphocyte subsets and minimal residual disease (MRD) were detected by flow cytometry. Function of bone marrow was monitored by methods of morphology, immunology, cytogenetics and molecular biology. The side effects were also observed during the treatment. The average follow-up period for all the 22 patients was 71 months and relapse occurred in two AML patients (9.1%). The percentage of CD3(+)/CD8(+) cells in peripheral blood of 15 patients at the 3rd month after DC-CIK treatment (36.73% ± 12.51%) was dramatically higher than that before treatment (29.20% ± 8.34%, P < 0.05). The MRD rate was >0.1% in 5 patients before the treatment, and became lower than 0.1% 3 months after the treatment. During the transfusion of DC-CIK, side effects including fever, chills and hives appeared in 7 out of 22 (31.82%) cases but disappeared quickly after symptomatic treatments. There were no changes in electrocardiography and liver-renal functions after the treatment. MRD in children with AML can be eliminated by DC-CIK therapy which is safe and has fewer side effects.

Research of digital controlled DC/DC converter based on STC12C5410AD

NASA Astrophysics Data System (ADS)

Chen, Dan-Jiang; Jin, Xin; Xiao, Zhi-Hong

2010-02-01

In order to study application of digital control technology on DC/DC converter, principle of increment mode PID control algorithm was analyzed in the paper. Then, a SCM named STC12C5410AD was introduced with its internal resources and characteristics. The PID control algorithm can be implemented easily based on it. The output of PID control was used to change the value of a variable that is 255 times than duty cycle, and this reduced the error of calculation. The valid of the presented algorithm was verified by an experiment for a BUCK DC/DC converter. The experimental results indicated that output voltage of the BUCK converter is stable with low ripple.

Pulsed Power Supply Based on Magnetic Energy Storage for Non-Destructive High Field Magnets

NASA Astrophysics Data System (ADS)

Aubert, G.; Defoug, S.; Joss, W.; Sala, P.; Dubois, M.; Kuchinsk, V.

2004-11-01

The first test results of a recently built pulsed power supply based on magnetic energy storage will be described. The system consists of the 16 kV shock alternator with a short-circuit power of 3600 MVA of the VOLTA Testing Center of the Schneider Electric SA company, a step-down transformer with a ratio of 1/24, a three-phase diode bridge designed for a current rising exponentially to 120 kA, and a big, 10 ton, heavy, 10 mH aluminum storage coil. The system is designed to store 72 MJ, normal operation will be at 50 MJ, and will work with voltages up to 20 kV. A transfer of 20% of the stored energy into the high field coil should be possible. Special making switches and interrupters have been developed to switch the high currents in a very short time. For safety and redundancy two independent monitoring systems control the energy transfer. A sequencing control system operates the switches on the ac side and protective switches on the dc side, a specially developed real-time control-monitoring system checks several currents and voltages and commands the dc circuit breakers and making switches.

Antigen presenting capacity of murine splenic myeloid cells.

PubMed

Hey, Ying-Ying; Quah, Benjamin; O'Neill, Helen C

2017-01-11

The spleen is an important site for hematopoiesis. It supports development of myeloid cells from bone marrow-derived precursors entering from blood. Myeloid subsets in spleen are not well characterised although dendritic cell (DC) subsets are clearly defined in terms of phenotype, development and functional role. Recently a novel dendritic-like cell type in spleen named 'L-DC' was distinguished from other known dendritic and myeloid cells by its distinct phenotype and developmental origin. That study also redefined splenic eosinophils as well as resident and inflammatory monocytes in spleen. L-DC are shown to be distinct from known splenic macrophages and monocyte subsets. Using a new flow cytometric procedure, it has been possible to identify and isolate L-DC in order to assess their functional competence and ability to activate T cells both in vivo and in vitro. L-DC are readily accessible to antigen given intravenously through receptor-mediated endocytosis. They are also capable of CD8 + T cell activation through antigen cross presentation, with subsequent induction of cytotoxic effector T cells. L-DC are MHCII - cells and unable to activate CD4 + T cells, a property which clearly distinguishes them from conventional DC. The myeloid subsets of resident monocytes, inflammatory monocytes, neutrophils and eosinophils, were found to have varying capacities to take up antigen, but were uniformly unable to activate either CD4 + T cells or CD8 + T cells. The results presented here demonstrate that L-DC in spleen are distinct from other myeloid cells in that they can process antigen for CD8 + T cell activation and induction of cytotoxic effector function, while both L-DC and myeloid subsets remain unable to activate CD4 + T cells. The L-DC subset in spleen is therefore distinct as an antigen presenting cell.

Targeting Toll-like receptor 7/8 enhances uptake of apoptotic leukemic cells by monocyte-derived dendritic cells but interferes with subsequent cytokine-induced maturation.

PubMed

van den Ancker, Willemijn; van Luijn, Marvin M; Ruben, Jurjen M; Westers, Theresia M; Bontkes, Hetty J; Ossenkoppele, Gert J; de Gruijl, Tanja D; van de Loosdrecht, Arjan A

2011-01-01

Therapeutic vaccination with dendritic cells (DC) is an emerging investigational therapy for eradication of minimal residual disease in acute myeloid leukemia. Various strategies are being explored in manufacturing DC vaccines ex vivo, e.g., monocyte-derived DC (MoDC) loaded with leukemia-associated antigens (LAA). However, the optimal source of LAA and the choice of DC-activating stimuli are still not well defined. Here, loading with leukemic cell preparations (harboring both unknown and known LAA) was explored in combination with a DC maturation-inducing cytokine cocktail (CC; IL-1β, IL-6, TNF-α, and PGE(2)) and Toll-like receptor ligands (TLR-L) to optimize uptake. Since heat shock induced apoptotic blasts were more efficiently taken up than lysates, we focused on uptake of apoptotic leukemic cells. Uptake of apoptotic blast was further enhanced by the TLR7/8-L R848 (20-30%); in contrast, CC-induced maturation inhibited uptake. CC, and to a lesser extent R848, enhanced the ability of MoDC to migrate and stimulate T cells. Furthermore, class II-associated invariant chain peptide expression was down-modulated after R848- or CC-induced maturation, indicating enhanced processing and presentation of antigenic peptides. To improve both uptake and maturation, leukemic cells and MoDC were co-incubated with R848 for 24 h followed by addition of CC. However, this approach interfered with CC-mediated MoDC maturation as indicated by diminished migratory and T cell stimulatory capacity, and the absence of IL-12 production. Taken together, our data demonstrate that even though R848 improved uptake of apoptotic leukemic cells, the sequential use of R848 and CC is counter-indicated due to its adverse effects on MoDC maturation.

Gene Expression Profiles of Human Dendritic Cells Interacting with Aspergillus fumigatus in a Bilayer Model of the Alveolar Epithelium/Endothelium Interface

PubMed Central

Morton, Charles Oliver; Fliesser, Mirjam; Dittrich, Marcus; Mueller, Tobias; Bauer, Ruth; Kneitz, Susanne; Hope, William; Rogers, Thomas Richard; Einsele, Hermann; Loeffler, Juergen

2014-01-01

The initial stages of the interaction between the host and Aspergillus fumigatus at the alveolar surface of the human lung are critical in the establishment of aspergillosis. Using an in vitro bilayer model of the alveolus, including both the epithelium (human lung adenocarcinoma epithelial cell line, A549) and endothelium (human pulmonary artery epithelial cells, HPAEC) on transwell membranes, it was possible to closely replicate the in vivo conditions. Two distinct sub-groups of dendritic cells (DC), monocyte-derived DC (moDC) and myeloid DC (mDC), were included in the model to examine immune responses to fungal infection at the alveolar surface. RNA in high quantity and quality was extracted from the cell layers on the transwell membrane to allow gene expression analysis using tailored custom-made microarrays, containing probes for 117 immune-relevant genes. This microarray data indicated minimal induction of immune gene expression in A549 alveolar epithelial cells in response to germ tubes of A. fumigatus. In contrast, the addition of DC to the system greatly increased the number of differentially expressed immune genes. moDC exhibited increased expression of genes including CLEC7A, CD209 and CCL18 in the absence of A. fumigatus compared to mDC. In the presence of A. fumigatus, both DC subgroups exhibited up-regulation of genes identified in previous studies as being associated with the exposure of DC to A. fumigatus and exhibiting chemotactic properties for neutrophils, including CXCL2, CXCL5, CCL20, and IL1B. This model closely approximated the human alveolus allowing for an analysis of the host pathogen interface that complements existing animal models of IA. PMID:24870357

Involvement of tumour necrosis factor-α-related apoptosis-inducing ligand in enhanced cytotoxicity of lipopolysaccharide-stimulated dendritic cells to activated T cells

PubMed Central

Yu, Yizhi; Liu, Shuxun; Wang, Wenya; Song, Wengang; Zhang, Minghui; Zhang, Weiping; Qin, Zhihai; Cao, Xuetao

2002-01-01

Dendritic cells (DC) are potent antigen-presenting cells (APC) specialized in T-cell mediated immune responses, and also play critical roles in the homeostasis of T cells for controlling immune responses. In the present study, we demonstrated that during mouse bone-marrow-derived DC activation of ovalbumin (OVA)-specific Ia-kb-restricted T hybridoma cells, MF2.2D9 and OVA257–264-specific H-2kb-restricted RF33.70 T cells, respectively, both hybridomas undergo cell death, partially mediated via apoptotic ligand–tumour necrosis factor-α (TNF-α)-related apoptosis-inducing ligand (TRAIL). Lipopolysaccharide enhanced the cytotoxic effect on the two activated T hybridoma cells, which was correlated with up-regulation of TRAIL-expression on DC to some extent. The activation of caspase-3 in activated T hybridoma cells cocultured with DC contributed to the programmed cell death pathway T cells underwent. Therefore, our results show that activation-induced cell death of T hybridoma cells can be influenced by DC, suggesting that DC may be involved in elimination of activated T cells at the end of primary immune responses. PMID:12100718

Involvement of tumour necrosis factor-alpha-related apoptosis-inducing ligand in enhanced cytotoxicity of lipopolysaccharide-stimulated dendritic cells to activated T cells.

PubMed

Yu, Yizhi; Liu, Shuxun; Wang, Wenya; Song, Wengang; Zhang, Minghui; Zhang, Weiping; Qin, Zhihai; Cao, Xuetao

2002-07-01

Dendritic cells (DC) are potent antigen-presenting cells (APC) specialized in T-cell mediated immune responses, and also play critical roles in the homeostasis of T cells for controlling immune responses. In the present study, we demonstrated that during mouse bone-marrow-derived DC activation of ovalbumin (OVA)-specific Ia-kb-restricted T hybridoma cells, MF2.2D9 and OVA257-264-specific H-2kb-restricted RF33.70 T cells, respectively, both hybridomas undergo cell death, partially mediated via apoptotic ligand-tumour necrosis factor-alpha (TNF-alpha)-related apoptosis-inducing ligand (TRAIL). Lipopolysaccharide enhanced the cytotoxic effect on the two activated T hybridoma cells, which was correlated with up-regulation of TRAIL-expression on DC to some extent. The activation of caspase-3 in activated T hybridoma cells cocultured with DC contributed to the programmed cell death pathway T cells underwent. Therefore, our results show that activation-induced cell death of T hybridoma cells can be influenced by DC, suggesting that DC may be involved in elimination of activated T cells at the end of primary immune responses.

High-frequency high-voltage high-power DC-to-DC converters

NASA Astrophysics Data System (ADS)

Wilson, T. G.; Owen, H. A., Jr.; Wilson, P. M.

1981-07-01

The current and voltage waveshapes associated with the power transitor and the power diode in an example current-or-voltage step-up (buck-boost) converter were analyzed to highlight the problems and possible tradeoffs involved in the design of high voltage high power converters operating at switching frequencies in the range of 100 Khz. Although the fast switching speeds of currently available power diodes and transistors permit converter operation at high switching frequencies, the resulting time rates of changes of current coupled with parasitic inductances in series with the semiconductor switches, produce large repetitive voltage transients across the semiconductor switches, potentially far in excess of the device voltage ratings. The need is established for semiconductor switch protection circuitry to control the peak voltages appearing across the semiconductor switches, as well as to provide the waveshaping action require for a given semiconductor device. The possible tradeoffs, as well as the factors affecting the tradeoffs that must be considered in order to maximize the efficiency of the converters are enumerated.

High-frequency high-voltage high-power DC-to-DC converters

NASA Technical Reports Server (NTRS)

Wilson, T. G.; Owen, H. A., Jr.; Wilson, P. M.

1981-01-01

The current and voltage waveshapes associated with the power transitor and the power diode in an example current-or-voltage step-up (buck-boost) converter were analyzed to highlight the problems and possible tradeoffs involved in the design of high voltage high power converters operating at switching frequencies in the range of 100 Khz. Although the fast switching speeds of currently available power diodes and transistors permit converter operation at high switching frequencies, the resulting time rates of changes of current coupled with parasitic inductances in series with the semiconductor switches, produce large repetitive voltage transients across the semiconductor switches, potentially far in excess of the device voltage ratings. The need is established for semiconductor switch protection circuitry to control the peak voltages appearing across the semiconductor switches, as well as to provide the waveshaping action require for a given semiconductor device. The possible tradeoffs, as well as the factors affecting the tradeoffs that must be considered in order to maximize the efficiency of the converters are enumerated.

Structural and morphological study on ZnO:Al thin films grown using DC magnetron sputtering

NASA Astrophysics Data System (ADS)

Astuti, B.; Sugianto; Mahmudah, S. N.; Zannah, R.; Putra, N. M. D.; Marwoto, P.; Aryanto, D.; Wibowo, E.

2018-03-01

ZnO doped Al (ZnO:Al ) thin film was deposited on corning glass substrate using DC magnetron sputtering method. Depositon process of the ZnO:Al thin films was kept constant at plasma power, deposition temperature and deposition time are 40 watt, 400°C and 2 hours, respectivelly. Furthermore, for annealing process has been done on the variation of oxygen pressure are 0, 50, and 100 mTorr. X-ray diffraction (XRD), and SEM was used to characterize ZnO:Al thin film was obtained. Based on XRD characterization results of the ZnO:Al thin film shows that deposited thin film has a hexagonal structure with the dominant diffraction peak at according to the orientation of the (002) plane and (101). Finally, the crystal structure of the ZnO:Al thin films that improves with an increasing the oxygen pressure at annealing process up to 100 mTorr and its revealed by narrow FWHM value and also with dense crystal structure.

Optimization of spin-torque switching using AC and DC pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunn, Tom; Kamenev, Alex; Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455

2014-06-21

We explore spin-torque induced magnetic reversal in magnetic tunnel junctions using combined AC and DC spin-current pulses. We calculate the optimal pulse times and current strengths for both AC and DC pulses as well as the optimal AC signal frequency, needed to minimize the Joule heat lost during the switching process. The results of this optimization are compared against numeric simulations. Finally, we show how this optimization leads to different dynamic regimes, where switching is optimized by either a purely AC or DC spin-current, or a combination AC/DC spin-current, depending on the anisotropy energies and the spin-current polarization.

DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikam, Pravin N., E-mail: pravinya26@gmail.com; Deshpande, Vineeta D., E-mail: drdeshpandevd@gmail.com

Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al{sub 2}O{sub 3}) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observedmore » at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σ{sub AC}) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher’s universal power law of solids. It revealed that σ{sub AC} of PET/alumina nanocomposites can be well characterized by the DC conductivity (σ{sub DC}), critical frequency (ω{sub c}), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σ{sub DC}) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.« less

Ad libitum fluid consumption via self- or external administration.

PubMed

Yeargin, Susan W; Finn, Megan E; Eberman, Lindsey E; Gage, Matthew J; McDermott, Brendon P; Niemann, Andrew

2015-01-01

During team athletic events, athletic trainers commonly provide fluids with water bottles. When a limited number of water bottles exist, various techniques are used to deliver fluids. To determine whether fluid delivered via water-bottle administration influenced fluid consumption and hydration status. Crossover study. Outdoor field (22.2°C ± 3.5°C). Nineteen participants (14 men, 5 women, age = 30 ± 10 years, height = 176 ± 8 cm, mass = 72.5 ± 10 kg) were recruited from the university and local running clubs. The independent variable was fluid delivery with 3 levels: self-administration with mouth-to-bottle direct contact (SA-DC), self-administration with no contact between mouth and bottle (SA-NC), and external administration with no contact between the mouth and the bottle (EA-NC). Participants warmed up for 10 minutes before completing 5 exercise stations, after which an ad libitum fluid break was given, for a total of 6 breaks. We measured the fluid variables of total volume consumed, total number of squirts, and average volume per squirt. Hydration status via urine osmolality and body-mass loss, and perceptual variables for thirst and fullness were recorded. We calculated repeated-measures analyses of variance to assess hydration status, fluid variables, and perceptual measures to analyze conditions across time. The total volume consumed for EA-NC was lower than for SA-DC (P = .001) and SA-NC (P = .001). The total number of squirts for SA-DC was lower than for SA-NC (P = .009). The average volume per squirt for EA-NC was lower than for SA-DC (P = .020) and SA-NC (P = .009). Participants arrived (601.0 ± 21.3 mOsm/L) and remained (622.3 ± 38.3 mOsm/L) hydrated, with no difference between conditions (P = .544); however, the EA-NC condition lost more body mass than did the SA-DC condition (P = .001). There was no main effect for condition on thirst (P = .147) or fullness (P = .475). External administration of fluid decreased total volume consumed via a decreased average volume per squirt. The SA-DC method requires fewer squirts within a specific time frame. Fluid breaks every 15 minutes resulted in maintenance of euhydration; however, loss of body mass was influenced by fluid administration. Athletic trainers should avoid external administration to promote positive hydration behaviors. When fluid is self-administered, individual bottles may be the best clinical practice because more volume can be consumed per squirt.

Chaos control in solar fed DC-DC boost converter by optimal parameters using nelder-mead algorithm powered enhanced BFOA

NASA Astrophysics Data System (ADS)

Sudhakar, N.; Rajasekar, N.; Akhil, Saya; Jyotheeswara Reddy, K.

2017-11-01

The boost converter is the most desirable DC-DC power converter for renewable energy applications for its favorable continuous input current characteristics. In other hand, these DC-DC converters known as practical nonlinear systems are prone to several types of nonlinear phenomena including bifurcation, quasiperiodicity, intermittency and chaos. These undesirable effects has to be controlled for maintaining normal periodic operation of the converter and to ensure the stability. This paper presents an effective solution to control the chaos in solar fed DC-DC boost converter since the converter experiences wide range of input power variation which leads to chaotic phenomena. Controlling of chaos is significantly achieved using optimal circuit parameters obtained through Nelder-Mead Enhanced Bacterial Foraging Optimization Algorithm. The optimization renders the suitable parameters in minimum computational time. The results are compared with the traditional methods. The obtained results of the proposed system ensures the operation of the converter within the controllable region.

Inferring rate and state friction parameters from a rupture model of the 1995 Hyogo-ken Nanbu (Kobe) Japan earthquake

USGS Publications Warehouse

Guatteri, Mariagiovanna; Spudich, P.; Beroza, G.C.

2001-01-01

We consider the applicability of laboratory-derived rate- and state-variable friction laws to the dynamic rupture of the 1995 Kobe earthquake. We analyze the shear stress and slip evolution of Ide and Takeo's [1997] dislocation model, fitting the inferred stress change time histories by calculating the dynamic load and the instantaneous friction at a series of points within the rupture area. For points exhibiting a fast-weakening behavior, the Dieterich-Ruina friction law, with values of dc = 0.01-0.05 m for critical slip, fits the stress change time series well. This range of dc is 10-20 times smaller than the slip distance over which the stress is released, Dc, which previous studies have equated with the slip-weakening distance. The limited resolution and low-pass character of the strong motion inversion degrades the resolution of the frictional parameters and suggests that the actual dc is less than this value. Stress time series at points characterized by a slow-weakening behavior are well fitted by the Dieterich-Ruina friction law with values of dc ??? 0.01-0.05 m. The apparent fracture energy Gc can be estimated from waveform inversions more stably than the other friction parameters. We obtain a Gc = 1.5??106 J m-2 for the 1995 Kobe earthquake, in agreement with estimates for previous earthquakes. From this estimate and a plausible upper bound for the local rock strength we infer a lower bound for Dc of about 0.008 m. Copyright 2001 by the American Geophysical Union.

RANKL-induced DC-STAMP Is Essential for Osteoclastogenesis

PubMed Central

Kukita, Toshio; Wada, Naohisa; Kukita, Akiko; Kakimoto, Takashi; Sandra, Ferry; Toh, Kazuko; Nagata, Kengo; Iijima, Tadahiko; Horiuchi, Madoka; Matsusaki, Hiromi; Hieshima, Kunio; Yoshie, Osamu; Nomiyama, Hisayuki

2004-01-01

Osteoclasts are bone-resorbing, multinucleated giant cells that are essential for bone remodeling and are formed through cell fusion of mononuclear precursor cells. Although receptor activator of nuclear factor–κB ligand (RANKL) has been demonstrated to be an important osteoclastogenic cytokine, the cell surface molecules involved in osteoclastogenesis are mostly unknown. Here, we report that the seven-transmembrane receptor-like molecule, dendritic cell–specific transmembrane protein (DC-STAMP) is involved in osteoclastogenesis. Expression of DC-STAMP is rapidly induced in osteoclast precursor cells by RANKL and other osteoclastogenic stimulations. Targeted inhibition of DC-STAMP by small interfering RNAs and specific antibody markedly suppressed the formation of multinucleated osteoclast-like cells. Overexpression of DC-STAMP enhanced osteoclastogenesis in the presence of RANKL. Furthermore, DC-STAMP directly induced the expression of the osteoclast marker tartrate-resistant acid phosphatase. These data demonstrate for the first time that DC-STAMP has an essential role in osteoclastogenesis. PMID:15452179

Microcurrent therapeutic technique for treatment of radiation toxicity

DOEpatents

Lennox, Arlene; Funder, Sandra

2000-01-01

The present technique provides a method of remediating the toxicities associated with radiation therapy. A conductive gel is applied to the affected bodily area. A sinusoidally pulsed biphasic DC current is then applied to the affected bodily area using at least one electrode. The electrode is manipulated using active tactile manipulation by for a predetermined time and the frequency of the sinusoidally pulsed biphasic DC current is decreased during the course of the treatment. The method also includes applying a spiked pulsed biphasic DC current to the affected bodily area using at least one electrode. This electrode is also manipulated using active tactile manipulation by for a predetermined time and the frequency of the spiked pulsed biphasic DC current is also decreased during the course of the treatment.

Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements.

PubMed

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

2013-12-01

The aim of this study was to measure the degree of conversion (DC) of five dual-curing resin cements after different curing modes with a second- and a third-generation light-emitting diode (LED) curing unit. Additionally, irradiance of both light curing units was measured at increasing distances and through discs of two glass ceramics for computer-aided design/manufacturing (CAD/CAM). Irradiance and spectra of the Elipar FreeLight 2 (Standard Mode (SM)) and of the VALO light curing unit (High Power Mode (HPM) and Xtra Power Mode (XPM)) were measured with a MARC radiometer. Irradiance was measured at increasing distances (control) and through discs (1.5 to 6 mm thickness) of IPS Empress CAD and IPS e.max CAD. DC of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA was measured with an attenuated total reflectance-Fourier transform infrared spectrometer when self-cured (negative control) or light cured in SM for 40 s, HPM for 32 s, or XPM for 18 s. Light curing was performed directly (positive control) or through discs of either 1.5- or 3-mm thickness of IPS Empress CAD or IPS e.max CAD. DC was analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). Maximum irradiances were 1,545 mW/cm(2) (SM), 2,179 mW/cm(2) (HPM), and 4,156 mW/cm(2) (XPM), and all irradiances decreased by >80 % through discs of 1.5 mm, ≥95 % through 3 mm, and up to >99 % through 6 mm. Generally, self-curing resulted in the lowest DC. For some cements, direct light curing did not result in higher DC compared to when light cured through ceramic discs. For other cements, light curing through ceramic discs of 3 mm generally reduced DC. Light curing was favourable for dual-curing cements. Some cements were more susceptible to variations in curing mode than others. When light curing a given cement, the higher irradiances of the third-generation LED curing unit resulted in similar DC compared to the second-generation one, though at shorter light curing times.

Design and Implementation of an Innovative Residential PV System

NASA Astrophysics Data System (ADS)

Najm, Elie Michel

This work focuses on the design and implementation of an innovative residential PV system. In chapter one, after an introduction related to the rapid growth of solar systems' installations, the most commonly used state of the art solar power electronics' configurations are discussed, which leads to introducing the proposed DC/DC parallel configuration. The advantages and disadvantages of each of the power electronics' configurations are deliberated. The scope of work in the power electronics is defined in this chapter to be related to the panel side DC/DC converter. System integration and mechanical proposals are also within the scope of work and are discussed in later chapters. Operation principle of a novel low cost PV converter is proposed in chapter 2. The proposal is based on an innovative, simplified analog implementation of a master/slave methodology resulting in an efficient, soft-switched interleaved variable frequency flybacks, operating in the boundary conduction mode (BCM). The scheme concept and circuit configuration, operation principle and theoretical waveforms, design equations, and design considerations are presented. Furthermore, design examples are also given, illustrating the significance of the newly derived frequency equation for flybacks operating in BCM. In chapters 3, 4, and 5, the design implementation and optimization of the novel DC/DC converter illustrated in chapter 2 are discussed. In chapter 3, a detailed variable frequency BCM flyback design model leading to optimizing the component selections and transformer design, detailed in chapter 4, is presented. Furthermore, in chapter 4, the method enabling the use of lower voltage rating switching devices is also discussed. In chapter 5, circuitry related to Start-UP, drive for the main switching devices, zero-voltage-switching (ZVS) as well as turn OFF soft switching and interleaving control are fully detailed. The experimental results of the proposed DC/DC converter are presented in chapter 6. In chapter 7, a novel integration method is proposed for the residential PV solar system. The proposal presents solutions to challenges experimented in the implementation of today's approaches. Faster installation time, easier system grounding, and integration of the power electronics in order to reduce the number of connectors' and system cost are detailed. Installers with special skills as well as special tools are not required for implementing the proposed system integration. Photos of the experimental results related to the installation of a 3kW system, which was fully completed in less than an hour and a half, are also presented.

The immunomodulator decoy receptor 3 improves locomotor functional recovery after spinal cord injury.

PubMed

Chiu, Chuan-Wen; Huang, Wen-Hung; Lin, Shao-Ji; Tsai, May-Jywan; Ma, Hsu; Hsieh, Shie-Liang; Cheng, Henrich

2016-06-17

Spinal cord injury (SCI) causes loss of neurons and axons and results in motor and sensory function impairments. SCI elicits an inflammatory response and induces the infiltration of immune cells, predominantly macrophages, to the injured site. Decoy receptor 3 (DcR3), also known as tumor necrosis factor receptor superfamily member (TNFRSF)-6B, is a pleiotropic immunomodulator capable of inducing macrophage differentiation into the M2 phenotype and enhancing angiogenesis. Because M2 macrophages are crucial for the recovery of impaired motor functions, we ask whether DcR3 is beneficial for the functional recovery of locomotion in Sprague-Dawley (SD) rats after SCI. Contusion injury of the spinal cord was performed using a New York University impactor at the ninth thoracic vertebrae, followed by intrathecal injection of 15 μg recombinant protein comprising DcR3 (DcR3.Fc) in 5 μl of normal saline as the treatment, or 5 μl of normal saline as the control, into the injury epicenter. Functional recovery was evaluated using an open-field test weekly up to 6 weeks after injury. The cavity size and myelin sparing in the rostral-to-caudal region, including the epicenter of the injury, were then examined in SCI rats by histological staining. The expression of anti-inflammatory cytokines and the presence of M2 macrophages were determined by quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry at 7 day after SCI. Statistical analysis was performed using a two-tailed Student's t test. Intrathecal administration of DcR3.Fc significantly improved locomotor function and reduced secondary injury with a smaller wound cavity and increased myelin sparing at the lesion site. Compared with the control group, DcR3.Fc-treated rats had increased vascularization at the injury epicenter along with higher levels of interleukin (IL)-4 and IL-10 and lower level of IL-1β on DcR3.Fc-treated rats at day 7 after SCI. Moreover, higher levels of arginase I (Arg I) and CD206 (M2 macrophage markers) and RECA-1 (endothelial marker) were observed in the epicenter on day 7 after SCI by immunofluorescence staining. These results indicated that DcR3.Fc may promote the M2 macrophage infiltration and enhanced angiogenesis at the lesion site, thus preserving a greater amount of spinal cord tissues and enhancing functional recovery after SCI.

Effects of decompressive craniectomy on functional outcomes and death in poor-grade aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis.

PubMed

Alotaibi, Naif M; Elkarim, Ghassan Awad; Samuel, Nardin; Ayling, Oliver G S; Guha, Daipayan; Fallah, Aria; Aldakkan, Abdulrahman; Jaja, Blessing N R; de Oliveira Manoel, Airton Leonardo; Ibrahim, George M; Macdonald, R Loch

2017-12-01

OBJECTIVE Patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH) (World Federation of Neurosurgical Societies Grade IV or V) are often considered for decompressive craniectomy (DC) as a rescue therapy for refractory intracranial hypertension. The authors performed a systematic review and meta-analysis to assess the impact of DC on functional outcome and death in patients after poor-grade aSAH. METHODS A systematic review and meta-analysis were performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles were identified through the Ovid Medline, Embase, Web of Science, and Cochrane Library databases from inception to October 2015. Only studies dedicated to patients with poor-grade aSAH were included. Primary outcomes were death and functional outcome assessed at any time period. Patients were grouped as having a favorable outcome (modified Rankin Scale [mRS] Scores 1-3, Glasgow Outcome Scale [GOS] Scores 4 and 5, extended Glasgow Outcome Scale [GOSE] Scores 5-8) or unfavorable outcome (mRS Scores 4-6, GOS Scores 1-3, GOSE Scores 1-4). Pooled estimates of event rates and odds ratios with 95% confidence intervals were calculated using the random-effects model. RESULTS Fifteen studies encompassing 407 patients were included in the meta-analysis (all observational cohorts). The pooled event rate for poor outcome across all studies was 61.2% (95% CI 52%-69%) and for death was 27.8% (95% CI 21%-35%) at a median of 12 months after aSAH. Primary (or early) DC resulted in a lower overall event rate for unfavorable outcome than secondary (or delayed) DC (47.5% [95% CI 31%-64%] vs 74.4% [95% CI 43%-91%], respectively). Among studies with comparison groups, there was a trend toward a reduced mortality rate 1-3 months after discharge among patients who did not undergo DC (OR 0.58 [95% CI 0.27-1.25]; p = 0.168). However, this trend was not sustained at the 1-year follow-up (OR 1.09 [95% CI 0.55-2.13]; p = 0.79). CONCLUSIONS Results of this study summarize the best evidence available in the literature for DC in patients with poor-grade aSAH. DC is associated with high rates of unfavorable outcome and death. Because of the lack of robust control groups in a majority of the studies, the effect of DC on functional outcomes versus that of other interventions for refractory intracranial hypertension is still unknown. A randomized trial is needed.

Chaos minimization in DC-DC boost converter using circuit parameter optimization

NASA Astrophysics Data System (ADS)

Sudhakar, N.; Natarajan, Rajasekar; Gourav, Kumar; Padmavathi, P.

2017-11-01

DC-DC converters are prone to several types of nonlinear phenomena including bifurcation, quasi periodicity, intermittency and chaos. These undesirable effects must be controlled for periodic operation of the converter to ensure the stability. In this paper an effective solution to control of chaos in solar fed DC-DC boost converter is proposed. Controlling of chaos is significantly achieved using optimal circuit parameters obtained through Bacterial Foraging Optimization Algorithm. The optimization renders the suitable parameters in minimum computational time. The obtained results are compared with the operation of traditional boost converter. Further the obtained results with BFA optimized parameter ensures the operations of the converter are within the controllable region. To elaborate the study of bifurcation analysis with optimized and unoptimized parameters are also presented.

DcR3 induces epithelial-mesenchymal transition through activation of the TGF-β3/SMAD signaling pathway in CRC.

PubMed

Liu, Yan-Ping; Zhu, Hui-Fang; Liu, Ding-Li; Hu, Zhi-Yan; Li, Sheng-Nan; Kan, He-Ping; Wang, Xiao-Yan; Li, Zu-Guo

2016-11-22

Decoy receptor 3 (DcR3), a novel member of the tumor necrosis factor receptor (TNFR) family, was recently reported to be associated with tumorigenesis and metastasis. However, the role of DcR3 in human colorectal cancer (CRC) has not been fully elucidated. In this study, we found that DcR3 expression was significantly higher in human colorectal cancer tissues than in paired normal tissues, and that DcR3 expression was strongly correlated with tumor invasion, lymph node metastases and poor prognoses. Moreover, DcR3 overexpression significantly enhanced CRC cell proliferation and migration in vitro and tumorigenesis in vivo. Conversely, DcR3 knockdown significantly repressed CRC cell proliferation and migration in vitro, and DcR3 deficiency also attenuated CRC tumorigenesis and metastasis in vivo. Functionally, DcR3 was essential for TGF-β3/SMAD-mediated epithelial-mesenchymal transition (EMT) of CRC cells. Importantly, cooperation between DcR3 and TGF-β3/SMAD-EMT signaling-related protein expression was correlated with survival and survival time in CRC patients. In conclusion, our results demonstrate that DcR3 may be a prognostic biomarker for CRC and that this receptor facilitates CRC development and metastasis by participating in TGF-β3/SMAD-mediated EMT of CRC cells.

NASA Administrator Bolden Volunteers with the DC Cares Program

NASA Image and Video Library

2009-12-14

NASA Administrator Charles Bolden spent time volunteering with DC Cares at the Park View Recreation Center in Washington, DC for their Santa's Workshop program, Monday, Dec. 14, 2009. Mr. Bolden spoke with students about his experience as a former NASA astronaut and current NASA Administrator, encouraging them to study math and science and to stay in school. Photo Credit: (NASA/Bill Ingalls)

Earth Day Park in Washington, D.C. to be Solar Powered

Science.gov Websites

Earth Day Park in Washington, D.C. to be Solar Powered For more information contact: Mike Marsh will illuminate Earth Day Park in Washington, D.C. just in time for the 26th annual celebration of Earth Day April 22, thanks to the U.S. Department of Energy and its National Renewable Energy Laboratory

Dyadic coping mediates the relationship between parents' grief and dyadic adjustment following the loss of a child.

PubMed

Albuquerque, Sara; Narciso, Isabel; Pereira, Marco

2018-01-01

This study aimed to examine forms of dyadic coping (DC) as mediators of the association between parents' grief response and dyadic adjustment and to determine whether these indirect effects were moderated by the child's type of death, timing of death, and age. The study design was cross-sectional. The sample consisted of 197 bereaved parents. Participants completed the Prolonged Grief Disorder Scale, Revised Dyadic Adjustment Scale, and Dyadic Coping Inventory. Significant indirect effects of parents' grief response on dyadic adjustment were found through stress communication by oneself and by the partner, positive and negative DC by the partner, and joint DC. The timing of death moderated the association between grief response and dyadic adjustment and between joint DC and dyadic adjustment. Grief response was negatively associated with dyadic adjustment only when the death occurred after birth. Grief response was negatively associated with joint DC, which, in turn, was positively associated with dyadic adjustment, when the death occurred both before and after birth. However, the association was stronger in the latter. Specific forms of DC might be mechanisms through which grief response is associated with dyadic adjustment and should be promoted in clinical practice.

Modeling and analysis of fractional order DC-DC converter.

PubMed

Radwan, Ahmed G; Emira, Ahmed A; AbdelAty, Amr M; Azar, Ahmad Taher

2017-07-11

Due to the non-idealities of commercial inductors, the demand for a better model that accurately describe their dynamic response is elevated. So, the fractional order models of Buck, Boost and Buck-Boost DC-DC converters are presented in this paper. The detailed analysis is made for the two most common modes of converter operation: Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM). Closed form time domain expressions are derived for inductor currents, voltage gain, average current, conduction time and power efficiency where the effect of the fractional order inductor is found to be strongly present. For example, the peak inductor current at steady state increases with decreasing the inductor order. Advanced Design Systems (ADS) circuit simulations are used to verify the derived formulas, where the fractional order inductor is simulated using Valsa Constant Phase Element (CPE) approximation and Generalized Impedance Converter (GIC). Different simulation results are introduced with good matching to the theoretical formulas for the three DC-DC converter topologies under different fractional orders. A comprehensive comparison with the recently published literature is presented to show the advantages and disadvantages of each approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Generalization of the Child-Langmuir law to the alternate extraction of positive and negative ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lafleur, T., E-mail: trevor.lafleur@lpp.polytechnique.fr; ONERA-The French Aerospace Lab, 91120 Palaiseau; Aanesland, A.

Using a combined analytical and simulation approach, we investigate positive and negative ion extraction between two electrodes from an ion-ion plasma source. With a square voltage waveform applied to the electrodes, we obtain approximate analytical solutions for the time-averaged extracted current densities, which are given simply by: J{sub p}{sup ac}=[α−fL√((M{sub p})/(q{sub p}V{sub 0}) )]J{sub p}{sup dc}, and J{sub n}{sup ac}=[(1−α)−fL√((M{sub n})/(q{sub n}V{sub 0}) )]J{sub n}{sup dc}, where J{sup ac} is the time-averaged current density, α is the square waveform duty cycle, f is the frequency, L is the electrode gap length, M is the ion mass, q is the ionmore » charge, V{sub 0} is the applied voltage amplitude, J{sup dc} is the dc extracted current density, and the subscripts p and n refer to positive and negative ions, respectively. In particular, if J{sup dc} is the dc space-charge limited current density, then these equations describe the square waveform generalization of the Child-Langmuir law.« less

PV source based high voltage gain current fed converter

NASA Astrophysics Data System (ADS)

Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

2017-11-01

This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

Cutting edge: impairment of dendritic cells and adaptive immunity by Ebola and Lassa viruses.

PubMed

Mahanty, Siddhartha; Hutchinson, Karen; Agarwal, Sudhanshu; McRae, Michael; Rollin, Pierre E; Pulendran, Bali

2003-03-15

Acute infection of humans with Ebola and Lassa viruses, two principal etiologic agents of hemorrhagic fevers, often results in a paradoxical pattern of immune responses: early infection, characterized by an outpouring of inflammatory mediators such as TNF-alpha, IL-1 beta, and IL-6, vs late stage infections, which are associated with poor immune responses. The mechanisms underlying these diverse outcomes are poorly understood. In particular, the role played by cells of the innate immune system, such as dendritic cells (DC), is not known. In this study, we show that Ebola and Lassa viruses infect human monocyte-derived DC and impair their function. Monocyte-derived DC exposed to either virus fail to secrete proinflammatory cytokines, do not up-regulate costimulatory molecules, and are poor stimulators of T cells. These data represent the first evidence for a mechanism by which Ebola and Lassa viruses target DC to impair adaptive immunity.

Engineered Lentivector Targeting of Dendritic Cells for In Vivo Immunization

PubMed Central

Yang, Lili; Yang, Haiguang; Rideout, Kendra; Cho, Taehoon; Joo, Kye il; Ziegler, Leslie; Elliot, Abigail; Walls, Anthony; Yu, Dongzi; Baltimore, David; Wang, Pin

2008-01-01

We report a method of inducing antigen production in dendritic cells (DCs) by in vivo targeting with lentiviral vectors that specifically bind to the DC surface protein, DC-SIGN. To target the DCs, the lentivector was enveloped with a viral glycoprotein from Sindbis virus, engineered to be DC-SIGN-specific. In vitro, this lentivector specifically transduced DCs and induced DC maturation. A remarkable frequency (up to 12%) of ovalbumin (OVA)-specific CD8+ T cells and a significant antibody response were observed 2 weeks following injection of a targeted lentiviral vector encoding an OVA transgene into naïve mice. These mice were solidly protected against the growth of the OVA-expressing E.G7 tumor and this methodology could even induce regression of an established tumor. Thus, lentiviral vectors targeting DCs provide a simple method of producing effective immunity and may provide an alternative route for immunization with protein antigens. PMID:18297056

Modeling and Synthesis Support for the North American Carbon Program

NASA Astrophysics Data System (ADS)

Baskaran, L.; Cook, R. B.; Thornton, P. E.; Post, W. M.; Wilson, B. E.; Dadi, U.

2007-12-01

The Modeling and Synthesis Thematic Data Center (MAST-DC) supports the North American Carbon Program by providing data products and data management services needed for modeling and synthesis activities. The overall objective of MAST-DC is to provide advanced data management support to NACP investigators doing modeling and synthesis, thereby freeing those investigators from having to perform data management functions. MAST-DC has compiled a number of data products for North America, including sub-pixel land-water content, daily meteorological data, and soil, land cover, and elevation data. In addition, we have developed an internet-based WebGIS system that enables users to browse, query, display, subset, and download spatial data using a standard web browser. For the mid-continent intensive, MAST-DC is working with a group of data assimilation modelers to generate a consistent set of meteorological data to drive bottom-up models.

A DC Transformer

NASA Technical Reports Server (NTRS)

Youngquist, Robert C.; Ihlefeld, Curtis M.; Starr, Stanley O.

2013-01-01

A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply can be stepped up (or down) with a corresponding step down (or up) in current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this de transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for de power transmission.

Helminth-conditioned dendritic cells prime CD4+ T cells to IL-4 production in vivo.

PubMed

Connor, Lisa M; Tang, Shiau-Choot; Camberis, Mali; Le Gros, Graham; Ronchese, Franca

2014-09-15

Dendritic cells (DC) are critical for the initiation of immune responses; however, their role in priming IL-4-producing Th2 cells in vivo is not fully understood. We used a model of intradermal injection with fluorescent-labeled, nonviable larvae from the helminth parasite nonviable Nippostrongylus brasiliensis L3 larvae (Nb), a strong inducer of Th2 responses, together with IL-4-GFP reporter mice that enable a sensitive detection of IL-4 production to examine the contribution of DC to the priming of IL-4-producing CD4(+) T cells in vivo. We found that parasite material is taken up by two distinct DC populations in draining lymph nodes: a mostly CD11c(int)MHC class II (MHCII)(hi)CD11b(+)Ly6C(-) dermal DC population and a CD11c(hi)MHCII(int)CD11b(+)Ly6C(+) monocyte-derived DC population. After Nb treatment, these two DC populations appeared in the draining lymph nodes in comparable numbers and with similar kinetics; however, treatment with pertussis toxin blocked the migration of dermal DC and the priming of IL-4-producing T cells, but only partially affected monocyte-derived DC numbers. In line with this observation, transfer of OVA-loaded CD11c(int)MHCII(hi) DC from Nb-treated mice into naive hosts could sensitize OVA-specific CD4(+) T cells to IL-4 production, whereas transfer of CD11c(int)MHCII(hi) DC from naive mice, or CD11c(hi)MHCII(int) DC from Nb-treated or naive mice, induced CD4(+) T cell expansion but no IL-4 production. Phenotypic analysis of Nb-loaded CD11c(int)MHCII(hi) DC revealed expression of programmed death ligand 2, CD301b, IFN regulatory factor 4, and moderate upregulation of OX40 ligand. However, thymic stromal lymphopoietin and OX40 ligand were not required for Th2 priming. Thus, our data suggest that appropriate stimuli can induce DC to express the unique signals sufficient to direct CD4(+) T cells to Th2 differentiation. Copyright © 2014 by The American Association of Immunologists, Inc.

Pump-Probe Noise Spectroscopy of Molecular Junctions.

PubMed

Ochoa, Maicol A; Selzer, Yoram; Peskin, Uri; Galperin, Michael

2015-02-05

The slow response of electronic components in junctions limits the direct applicability of pump-probe type spectroscopy in assessing the intramolecular dynamics. Recently the possibility of getting information on a sub-picosecond time scale from dc current measurements was proposed. We revisit the idea of picosecond resolution by pump-probe spectroscopy from dc measurements and show that any intramolecular dynamics not directly related to charge transfer in the current direction is missed by current measurements. We propose a pump-probe dc shot noise spectroscopy as a suitable alternative. Numerical examples of time-dependent and average responses of junctions are presented for generic models.

Ultrafast strong-field photoelectron emission from biased metal surfaces: exact solution to time-dependent Schrödinger Equation

PubMed Central

Zhang, Peng; Lau, Y. Y.

2016-01-01

Laser-driven ultrafast electron emission offers the possibility of manipulation and control of coherent electron motion in ultrashort spatiotemporal scales. Here, an analytical solution is constructed for the highly nonlinear electron emission from a dc biased metal surface illuminated by a single frequency laser, by solving the time-dependent Schrödinger equation exactly. The solution is valid for arbitrary combinations of dc electric field, laser electric field, laser frequency, metal work function and Fermi level. Various emission mechanisms, such as multiphoton absorption or emission, optical or dc field emission, are all included in this single formulation. The transition between different emission processes is analyzed in detail. The time-dependent emission current reveals that intense current modulation may be possible even with a low intensity laser, by merely increasing the applied dc bias. The results provide insights into the electron pulse generation and manipulation for many novel applications based on ultrafast laser-induced electron emission. PMID:26818710

Maturation of monocyte derived dendritic cells with OK432 boosts IL-12p70 secretion and conveys strong T-cell responses

PubMed Central

2011-01-01

Background Design of tumour specific immunotherapies using the patients' own dendritic cells (DC) is a fast advancing scientific field. The functional qualities of the DC generated in vitro are critical, and today's gold standard for maturation is a cytokine cocktail consisting of IL-1β, IL-6, TNF-α and PGE2 generating cells lacking IL-12p70 production. OK432 is an immunotherapeutic agent derived from killed Streptococcus pyogenes that has been used clinically to treat malignant and benign neoplasms for decades. Methods In this study, we analysed the effects of OK432 on DC maturation, DC migration, cytokine and chemokine secretion as well as T-cell stimulatory capacity, and compared it to the cytokine cocktail alone and combinations of OK432 with the cytokine cocktail. Results OK432 induced a marked up-regulation of CD40 on the cell surface as well as a strong inflammatory response from the DC with significantly more secretion of 19 different cytokines and chemokines compared to the cytokine cocktail. Interestingly, secretion of IL-15 and IL-12p70 was detected at high concentrations after maturation of DC with OK432. However, the OK432 treated DC did not migrate as well as DC treated with cytokine cocktail in a transwell migration assay. During allogeneic T-cell stimulation OK432 treated DC induced proliferation of over 50 percent of CD4 and 30 percent of CD8 T-cells for more than two cell divisions, whereas cytokine cocktail treated DC induced proliferation of 12 and 11 percent of CD4 and CD8 T-cells, respectively. Conclusions The clinically approved compound OK432 has interesting properties that warrants its use in DC immunotherapy and should be considered as a potential immunomodulating agent in cancer immunotherapy. PMID:21208424

Design of an Autonomous Underwater Vehicle (AUV) Charging System for Underway, Underwater Recharging

DTIC Science & Technology

2014-05-09

again increase the size of the system. A comparison between switching frequency and efficiency for a nominal DC/DC converter was done in an EE ...Choosing the Optimum Switching Frequency of your DC / DC Converter,” EE Times, pp. 1–7, 2006. [19] ON Semiconductors, “Effects of High Switching Frequency...3.1W OUTPUT FILTER CAPACITOR EEE -FC1H101P 100uF ELECTROLYTIC 50V OUTPUT FILTER CAPACITOR C5750X7S2A106M230KB 10uF CERAMIC 100V

State trajectories used to observe and control dc-to-dc converters

NASA Technical Reports Server (NTRS)

Burns, W. W., III; Wilson, T. G.

1976-01-01

State-plane analysis techniques are employed to study the voltage stepup energy-storage dc-to-dc converter. Within this framework, an example converter operating under the influence of a constant on-time and a constant frequency controller is examined. Qualitative insight gained through this approach is used to develop a conceptual free-running control law for the voltage stepup converter which can achieve steady-state operation in one on/off cycle of control. Digital computer simulation data are presented to illustrate and verify the theoretical discussions presented.

Modeling and real time simulation of an HVDC inverter feeding a weak AC system based on commutation failure study.

PubMed

Mankour, Mohamed; Khiat, Mounir; Ghomri, Leila; Chaker, Abdelkader; Bessalah, Mourad

2018-06-01

This paper presents modeling and study of 12-pulse HVDC (High Voltage Direct Current) based on real time simulation where the HVDC inverter is connected to a weak AC system. In goal to study the dynamic performance of the HVDC link, two serious kind of disturbance are applied at HVDC converters where the first one is the single phase to ground AC fault and the second one is the DC link to ground fault. The study is based on two different mode of analysis, which the first is to test the performance of the DC control and the second is focalized to study the effect of the protection function on the system behavior. This real time simulation considers the strength of the AC system to witch is connected and his relativity with the capacity of the DC link. The results obtained are validated by means of RT-lab platform using digital Real time simulator Hypersim (OP-5600), the results carried out show the effect of the DC control and the influence of the protection function to reduce the probability of commutation failures and also for helping inverter to take out from commutation failure even while the DC control fails to eliminate them. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Quality Indicators for Human Milk Use in Very Low Birthweight Infants: Are We Measuring What We Should be Measuring?

PubMed Central

Bigger, Harold R.; Fogg, Louis J.; Patel, Aloka; Johnson, Tricia; Engstrom, Janet L.; Meier, Paula P.

2014-01-01

Objective The objective of this study was to compare the currently used human milk (HM) quality indicators that measure whether very low birthweight (VLBW; <1500 g birthweight) infants “ever” received HM and whether they were still receiving HM at discharge from the neonatal intensive care unit (NICU) to the actual amount and timing of HM received. Study Design This study used data from a large NIH-funded cohort study and calculated whether VLBW infants ever received HM (HM-Ever) and of these infants, the percentage who were still receiving HM at NICU discharge (HM-DC). Then, the HM-DC indicator (exclusive, partial and none) was compared with the amount and timing of HM feedings received by these same infants. Results Of the 291 VLBW infants who met inclusion criteria, 285 received some HM (HM-Ever = 98%). At NICU discharge (HM-DC), 24.2%, 15.1% and 60.7% were receiving exclusive, partial and no HM, respectively. Of the 60.7% infants with no HM-DC, some had received higher amounts of HM during the NICU hospitalization than infants categorized as exclusive and partial for HM-DC. Of the infants with no HM-DC, 76.8% and 59.7% had received exclusive HM during the Days 1–14 and Days 1–28 exposure periods, respectively. Conclusion The average daily dose (HM-DD; in mL/kg/d) and cumulative percentage (HM-PCT; as % of cumulative enteral intake) of HM feedings were sufficient to significantly reduce the risk of multiple morbidities, including late onset sepsis, necrotizing enterocolitis, neurocognitive delay and rehospitalization, in the majority of the VLBW infants who were discharged with no HM-DC. Quality indicators that focus on the amount and timing of HM feedings in the NICU should be added to the HM-Ever and HM-DC measures. PMID:24526005

Frequency multiplexed flux locked loop architecture providing an array of DC SQUIDS having both shared and unshared components

DOEpatents

Ganther, Jr., Kenneth R.; Snapp, Lowell D.

2002-01-01

Architecture for frequency multiplexing multiple flux locked loops in a system comprising an array of DC SQUID sensors. The architecture involves dividing the traditional flux locked loop into multiple unshared components and a single shared component which, in operation, form a complete flux locked loop relative to each DC SQUID sensor. Each unshared flux locked loop component operates on a different flux modulation frequency. The architecture of the present invention allows a reduction from 2N to N+1 in the number of connections between the cryogenic DC SQUID sensors and their associated room temperature flux locked loops. Furthermore, the 1.times.N architecture of the present invention can be paralleled to form an M.times.N array architecture without increasing the required number of flux modulation frequencies.

Application of drive circuit based on L298N in direct current motor speed control system

NASA Astrophysics Data System (ADS)

Yin, Liuliu; Wang, Fang; Han, Sen; Li, Yuchen; Sun, Hao; Lu, Qingjie; Yang, Cheng; Wang, Quanzhao

2016-10-01

In the experiment of researching the nanometer laser interferometer, our design of laser interferometer circuit system is up to the wireless communication technique of the 802.15.4 IEEE standard, and we use the RF TI provided by Basic to receive the data on speed control system software. The system's hardware is connected with control module and the DC motor. However, in the experiment, we found that single chip microcomputer control module is very difficult to drive the DC motor directly. The reason is that the DC motor's starting and braking current is larger than the causing current of the single chip microcomputer control module. In order to solve this problem, we add a driving module that control board can transmit PWM wave signal through I/O port to drive the DC motor, the driving circuit board can come true the function of the DC motor's positive and reversal rotation and speed adjustment. In many various driving module, the L298N module's integrated level is higher compared with other driver module. The L298N model is easy to control, it not only can control the DC motor, but also achieve motor speed control by modulating PWM wave that the control panel output. It also has the over-current protection function, when the motor lock, the L298N model can protect circuit and motor. So we use the driver module based on L298N to drive the DC motor. It is concluded that the L298N driver circuit module plays a very important role in the process of driving the DC motor in the DC motor speed control system.

Inspection of anode and field wires for the COMPASS drift chamber, DC5, with Environmental Scanning Electron Microscope

NASA Astrophysics Data System (ADS)

Cyuzuzo, Sonia

2014-09-01

The COMPASS experiment at CERN uses a secondary pion beam from the Super Proton Synchrotron (SPS) at CERN to explore the spin structure of nucleons. A new drift chamber, DC5, will be integrated into the COMPASS spectrometer to replace an aging straw tube detector. DC5 will detect muon pairs from Drell-Yan scattering of a pion-beam off a transversely polarized proton target. This data will be used to determine the correlation between transverse proton spin and the intrinsic transverse momentum of up-quarks inside the proton, the Sivers effect. DC5 is a large area planar drift chamber with 8 layers of anode-frames made of G10 fiberglass-epoxy. The G10 frames support printed circuit boards for soldering 20 μm diameter anode and 100 μm diameter field wires. The anode planes are sandwiched by 13 graphite coated Mylar cathode planes. To ensure a well-functioning of DC5, the wires were carefully tested. An optical inspection and a spectral analysis was performed with an Environmental Scanning Electron Microscope (ESEM) to verify the composition and dimensions and the integrity of the gold plating on the surface of these wires. The spectra of the wires were studied at 10 and 30 keV. The COMPASS experiment at CERN uses a secondary pion beam from the Super Proton Synchrotron (SPS) at CERN to explore the spin structure of nucleons. A new drift chamber, DC5, will be integrated into the COMPASS spectrometer to replace an aging straw tube detector. DC5 will detect muon pairs from Drell-Yan scattering of a pion-beam off a transversely polarized proton target. This data will be used to determine the correlation between transverse proton spin and the intrinsic transverse momentum of up-quarks inside the proton, the Sivers effect. DC5 is a large area planar drift chamber with 8 layers of anode-frames made of G10 fiberglass-epoxy. The G10 frames support printed circuit boards for soldering 20 μm diameter anode and 100 μm diameter field wires. The anode planes are sandwiched by 13 graphite coated Mylar cathode planes. To ensure a well-functioning of DC5, the wires were carefully tested. An optical inspection and a spectral analysis was performed with an Environmental Scanning Electron Microscope (ESEM) to verify the composition and dimensions and the integrity of the gold plating on the surface of these wires. The spectra of the wires were studied at 10 and 30 keV. Acknowledging NSF and UIUC.

DC-8 Scanning Lidar Characterization of Aircraft Contrails and Cirrus Clouds

NASA Technical Reports Server (NTRS)

Uthe, Edward E.; Nielsen, Norman B.; Oseberg, Terje E.

1998-01-01

An angular-scanning large-aperture (36 cm) backscatter lidar was developed and deployed on the NASA DC-8 research aircraft as part of the SUCCESS (Subsonic Aircraft: Contrail and Cloud Effects Special Study) program. The lidar viewing direction could be scanned continuously during aircraft flight from vertically upward to forward to vertically downward, or the viewing could be at fixed angles. Real-time pictorial displays generated from the lidar signatures were broadcast on the DC-8 video network and used to locate clouds and contrails above, ahead of, and below the DC-8 to depict their spatial structure and to help select DC-8 altitudes for achieving optimum sampling by onboard in situ sensors. Several lidar receiver systems and real-time data displays were evaluated to help extend in situ data into vertical dimensions and to help establish possible lidar configurations and applications on future missions. Digital lidar signatures were recorded on 8 mm Exabyte tape and generated real-time displays were recorded on 8mm video tape. The digital records were transcribed in a common format to compact disks to facilitate data analysis and delivery to SUCCESS participants. Data selected from the real-time display video recordings were processed for publication-quality displays incorporating several standard lidar data corrections. Data examples are presented that illustrate: (1) correlation with particulate, gas, and radiometric measurements made by onboard sensors, (2) discrimination and identification between contrails observed by onboard sensors, (3) high-altitude (13 km) scattering layer that exhibits greatly enhanced vertical backscatter relative to off-vertical backscatter, and (4) mapping of vertical distributions of individual precipitating ice crystals and their capture by cloud layers. An angular scan plotting program was developed that accounts for DC-8 pitch and velocity.

An Attempt to Shorten Loading Time of Epirubicin into DC Beads® Using Vibration and a Sieve.

PubMed

Sonoda, Akinaga; Nitta, Norihisa; Yamamoto, Takefumi; Tomozawa, Yuki; Ohta, Shinichi; Watanabe, Shobu; Murata, Kiyoshi

2017-04-01

We investigated the possibility of shortening the time required for loading epirubicin into calibrated polyvinyl alcohol-based hydrogel beads (DC Beads ® ) to be used for transarterial chemoembolization. After separating the beads suspended in phosphate-buffered saline (PBS) solution by the use of a sieve (clearance 75 µm), epirubicin hydrochloride (EH) was loaded for 20, 30, or 60 s under vibration into DC beads. The EH loading rate into conventionally prepared (control) beads, i.e., beads loaded for 30 min without vibration, and vibration-loaded beads were calculated from the residual EH concentration in the bead-depleted EH solution. The amount of EH eluted from conventionally and vibration-loaded samples into a PBS solution (pH 7.0) was measured at 15 and 30 min and 1, 2, 6, 12, and 24 h. We also recorded the inhibitory effect of the PBS solution on the loading time. Using frozen sections, the EH load in the beads was evaluated visually under a fluorescence microscope. Spectrophotometry (495 nm) showed that the loading rate was 98.98 ± 0.34, 99.02 ± 0.32, and 99.50 ± 0.11 % with 20-, 30-, and 60-s vibration, respectively. The eluted rate was statistically similar between vibration- and statically loaded (control) beads. The PBS solution hampered EH loading into the beads. Visually, the distribution of EH in conventionally and vibration-loaded DC beads was similar. The use of vibration and the removal of PBS solution when epirubicin hydrochloride was loaded into DC beads dramatically shortened the loading time of epirubicin hydrochloride into DC beads.

E-beam high voltage switching power supply

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1997-01-01

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

E-beam high voltage switching power supply

DOEpatents

Shimer, D.W.; Lange, A.C.

1997-03-11

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360{degree}/n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load. 7 figs.

Assessment of Anthropogenic and Biomass Burning Impact on Aerosol Properties over California as Observed During ARCTAS-CA

NASA Astrophysics Data System (ADS)

Thornhill, K. L.; Anderson, B.; Chen, G.; Beyersdorf, A. J.; Winstead, E. L.; Dibb, J. E.; Scheuer, E. M.; Weber, R.; Lathem, T. L.; Jimenez, J. L.; Cubison, M.; Kondo, Y.; Wennberg, P. O.; Weinheimer, A. J.; Wisthaler, A.

2009-12-01

In the summer of 2008, measurements of aerosols were made on-board the NASA DC-8 over the state of California, as part of the second phase of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) on behalf of the California Air resources Board (CARB). The DC-8 made four flights, between 18 June and 26 June, totaling 33 hours, to examine California’s atmosphere to better understand the chemical dynamics of smog and greenhouse gases over the state. Serendipitously, from a science perspective, this time period was marked by numerous wildfires spread throughout the state. The NASA DC-8 had a suite of aerosol instruments, capable of measuring the number concentrations, optical properties, and size distributions of aerosols between 0.003 and 1500 um. In this presentation, we will characterize aerosols sampled over the Los Angeles basin, which included several missed approaches at Los Angeles International Airport (LAX), traverses through the Long Beach and Santa Barbara ship channels, sampling in and out of the marine boundary layer, and encounters with outflow of forest fires mixed with urban smog. The evolution of the aerosols during the day will be examined, as the smog builds up within the basin and the plume travels out of the basin into the surrounding atmosphere.

Gigantic 2D laser-induced photovoltaic effect in magnetically doped topological insulators for surface zero-bias spin-polarized current generation

NASA Astrophysics Data System (ADS)

Shikin, A. M.; Voroshin, V. Yu; Rybkin, A. G.; Kokh, K. A.; Tereshchenko, O. E.; Ishida, Y.; Kimura, A.

2018-01-01

A new kind of 2D photovoltaic effect (PVE) with the generation of anomalously large surface photovoltage up to 210 meV in magnetically doped topological insulators (TIs) has been studied by the laser time-resolved pump-probe angle-resolved photoelectron spectroscopy. The PVE has maximal efficiency for TIs with high occupation of the upper Dirac cone (DC) states and the Dirac point located inside the fundamental energy gap. For TIs with low occupation of the upper DC states and the Dirac point located inside the valence band the generated surface photovoltage is significantly reduced. We have shown that the observed giant PVE is related to the laser-generated electron-hole asymmetry followed by accumulation of the photoexcited electrons at the surface. It is accompanied by the 2D relaxation process with the generation of zero-bias spin-polarized currents flowing along the topological surface states (TSSs) outside the laser beam spot. As a result, the spin-polarized current generates an effective in-plane magnetic field that is experimentally confirmed by the k II-shift of the DC relative to the bottom non-spin-polarized conduction band states. The realized 2D PVE can be considered as a source for the generation of zero-bias surface spin-polarized currents and the laser-induced local surface magnetization developed in such kind 2D TSS materials.

Optoelectronic frequency discriminated phase tuning technology and its applications

NASA Astrophysics Data System (ADS)

Lin, Gong-Ru; Chang, Yung-Cheng

2000-07-01

By using a phase-tunable optoelectronic phase-locked loop, we are able to continuously change the phase as well as the delay-time of optically distributed microwave clock signals or optical pulse train. The advantages of the proposed technique include such as wide-band operation up to 20GHz, wide-range tuning up to 640 degrees, high tuning resolution of <6x10-2 degree/mV, ultra-low short-term phase fluctuation and drive of 4.7x10-2 degree and 3.4x10- 3 degree/min, good linearity with acceptable deviations, and frequency-independent transferred function with slope of nearly 90 degrees/volt, etc. The novel optoelectronic phase shifter is performed by using a DC-voltage controlled, optoelectronic-mixer-based, frequency-down-converted digital phase-locked-loop. The maximum delay-time is continuously tunable up to 3.9 ns for optical pulses repeated at 500 MHz from a gain-switched laser diode. This corresponds to a delay responsivity of about 0.54 ps/mV. The using of the OEPS as being an optoelectronic delay-time controller for optical pulses is demonstrated with temporal resolution of <0.2 ps. Electro-optic sampling of high-frequency microwave signals by using the in-situ delay-time-tunable pulsed laser as a novel optical probe is primarily reported.

DcR3 induces epithelial-mesenchymal transition through activation of the TGF-β3/SMAD signaling pathway in CRC

PubMed Central

Hu, Zhi-Yan; Li, Sheng-Nan; Kan, He-Ping; Wang, Xiao-Yan; Li, Zu-Guo

2016-01-01

Decoy receptor 3 (DcR3), a novel member of the tumor necrosis factor receptor (TNFR) family, was recently reported to be associated with tumorigenesis and metastasis. However, the role of DcR3 in human colorectal cancer (CRC) has not been fully elucidated. In this study, we found that DcR3 expression was significantly higher in human colorectal cancer tissues than in paired normal tissues, and that DcR3 expression was strongly correlated with tumor invasion, lymph node metastases and poor prognoses. Moreover, DcR3 overexpression significantly enhanced CRC cell proliferation and migration in vitro and tumorigenesis in vivo. Conversely, DcR3 knockdown significantly repressed CRC cell proliferation and migration in vitro, and DcR3 deficiency also attenuated CRC tumorigenesis and metastasis in vivo. Functionally, DcR3 was essential for TGF-β3/SMAD-mediated epithelial-mesenchymal transition (EMT) of CRC cells. Importantly, cooperation between DcR3 and TGF-β3/SMAD-EMT signaling-related protein expression was correlated with survival and survival time in CRC patients. In conclusion, our results demonstrate that DcR3 may be a prognostic biomarker for CRC and that this receptor facilitates CRC development and metastasis by participating in TGF-β3/SMAD-mediated EMT of CRC cells. PMID:27764793

Experimental and modeling study of high performance direct carbon solid oxide fuel cell with in situ catalytic steam-carbon gasification reaction

NASA Astrophysics Data System (ADS)

Xu, Haoran; Chen, Bin; Zhang, Houcheng; Tan, Peng; Yang, Guangming; Irvine, John T. S.; Ni, Meng

2018-04-01

In this paper, 2D models for direct carbon solid oxide fuel cells (DC-SOFCs) with in situ catalytic steam-carbon gasification reaction are developed. The simulation results are found to be in good agreement with experimental data. The performance of DC-SOFCs with and without catalyst are compared at different operating potential, anode inlet gas flow rate and operating temperature. It is found that adding suitable catalyst can significantly speed up the in situ steam-carbon gasification reaction and improve the performance of DC-SOFC with H2O as gasification agent. The potential of syngas and electricity co-generation from the fuel cell is also evaluated, where the composition of H2 and CO in syngas can be adjusted by controlling the anode inlet gas flow rate. In addition, the performance DC-SOFCs and the percentage of fuel in the outlet gas are both increased with increasing operating temperature. At a reduced temperature (below 800 °C), good performance of DC-SOFC can still be obtained with in-situ catalytic carbon gasification by steam. The results of this study form a solid foundation to understand the important effect of catalyst and related operating conditions on H2O-assisted DC-SOFCs.

Decompressive craniectomy and CSF disorders in children.

PubMed

Manfiotto, Marie; Mottolese, Carmine; Szathmari, Alexandru; Beuriat, Pierre-Aurelien; Klein, Olivier; Vinchon, Matthieu; Gimbert, Edouard; Roujeau, Thomas; Scavarda, Didier; Zerah, Michel; Di Rocco, Federico

2017-10-01

Decompressive craniectomy (DC) is a lifesaving procedure but is associated to several post-operative complications, namely cerebrospinal fluid (CSF) dynamics impairment. The aim of this multicentric study was to evaluate the incidence of such CSF alterations after DC and review their impact on the overall outcome. We performed a retrospective multicentric study to analyze the CSF disorders occurring in children aged from 0 to 17 years who had undergone a DC for traumatic brain injury (TBI) in the major Departments of Pediatric Neurosurgery of France between January 2006 and August 2016. Out of 150 children, ranging in age between 7 months and 17 years, mean 10.75 years, who underwent a DC for TBI in 10 French pediatric neurosurgical centers. Sixteen (6 males, 10 females) (10.67%) developed CSF disorders following the surgical procedure and required an extrathecal CSF shunting. External ventricular drainage increased the risk of further complications, especially cranioplasty infection (p = 0.008). CSF disorders affect a minority of children after DC for TBI. They may develop early after the DC but they may develop several months after the cranioplasty (8 months), consequently indicating the necessity of clinical and radiological close follow-up after discharge from the neurosurgical unit. External ventricular drainage and permanent CSF shunt placement increase significantly the risk of cranioplasty infection.

Response of double cropping suitability to climate change in the United States

NASA Astrophysics Data System (ADS)

Seifert, Christopher A.; Lobell, David B.

2015-02-01

In adapting US agriculture to the climate of the 21st century, a key unknown is whether cropping frequency may increase, helping to offset projected negative yield impacts in major production regions. Combining daily weather data and crop phenology models, we find that cultivated area in the US suited to dryland winter wheat-soybeans, the most common double crop (DC) system, increased by up to 28% from 1988 to 2012. Changes in the observed distribution of DC area over the same period agree well with this suitability increase, evidence consistent with climate change playing a role in recent DC expansion in phenologically constrained states. We then apply the model to projections of future climate under the RCP45 and RCP85 scenarios and estimate an additional 126-239% increase, respectively, in DC area. Sensitivity tests reveal that in most instances, increases in mean temperature are more important than delays in fall freeze in driving increased DC suitability. The results suggest that climate change will relieve phenological constraints on wheat-soy DC systems over much of the United States, though it should be recognized that impacts on corn and soybean yields in this region are expected to be negative and larger in magnitude than the 0.4-0.75% per decade benefits we estimate here for double cropping.

Leishmania major Infection Activates NF-κB and Interferon Regulatory Factors 1 and 8 in Human Dendritic Cells▿

PubMed Central

Jayakumar, Asha; Donovan, Michael J.; Tripathi, Vinita; Ramalho-Ortigao, Marcelo; McDowell, Mary Ann

2008-01-01

The salient feature of dendritic cells (DC) is the initiation of appropriate adaptive immune responses by discriminating between pathogens. Using a prototypic model of intracellular infection, we previously showed that Leishmania major parasites prime human DC for efficient interleukin-12 (IL-12) secretion. L. major infection is associated with self-limiting cutaneous disease and powerful immunity. In stark contrast, the causative agent of visceral leishmaniasis, Leishmania donovani, does not prime human DC for IL-12 production. Here, we report that DC priming by L. major infection results in the early activation of NF-κB transcription factors and the up-regulation and nuclear translocation of interferon regulatory factor 1 (IRF-1) and IRF-8. The inhibition of NF-κB activation by the pretreatment of DC with caffeic acid phenethyl ester blocks L. major-induced IRF-1 and IRF-8 activation and IL-12 expression. We further demonstrate that IRF-1 and IRF-8 obtained from L. major-infected human DC specifically bind to their consensus binding sites on the IL-12p35 promoter, indicating that L. major infection either directly stimulates a signaling cascade or induces an autocrine pathway that activates IRF-1 and IRF-8, ultimately resulting in IL-12 transcription. PMID:18316378

Kevlar/PMR-15 reduced drag DC-9 reverser stang fairing

NASA Technical Reports Server (NTRS)

Kawai, R. T.

1982-01-01

A reduced drag fairing for the afterbody enclosing the thrust reverser actuators on the DC-9 has been developed with Kevlar-49/PMR-15 advanced composite material. The improved fairing reduces airplane drag 1% compared to the production baseline. Use of composites reduces weight 40% compared to an equivalent metal fairing. The Kevlar-49/PMR-15 advanced composite is an organic matrix material system that can be used at temperatures up to 500 F.

Granulocyte-macrophage colony-stimulating factor induces the differentiation of murine erythroleukaemia cells into dendritic cells.

PubMed Central

Cao, X; Zhao, Y; Yu, Y; Wang, Y; Zhang, M; Zhang, W; Wang, J

1998-01-01

Dendritic cells (DC) are professional antigen-presenting cells (APC) within the immune system and antigen-pulsed DC can be used as an effective vaccine for active immunotherapy of cancer. Granulocyte-macrophage colony-stimulating factor (GM-CSF) plays an important role in the generation of DC. We previously showed that GM-CSF can induce murine erythroleukaemia cells (FBL-3) to differentiate into monocyte-like cells. To develop a new vaccinating method to stimulate the host immune response to leukaemia, we further investigate whether FBL-3 cells induced by GM-CSF can differentiate into DC in the present study. After being treated with GM-CSF, FBL-3 cells expressed high levels of 33D1 and NLDC-145, which are the specific markers of DC. The expression of MHC-II, B7-1, B7-2 and vascular cell adhesion molecule-1 (VCAM-1) was up-regulated markedly; the typical morphology of DC were also observed by electron microscopy. Functionally, the GM-CSF-induced FBL-3 cells could apparently stimulate the proliferation of naive allogeneic and autologous T lymphocytes and induce the generation of specific CTL more efficiently than the wild-type FBL-3 cells. Mice immunized with GM-CSF-induced FBL-3 cells could resist the subsequent challenge with the wild-type FBL-3 cells. Collectively, these data indicate that GM-CSF differentiates murine erythroleukaemia cells into DC phenotypically, morphologically and functionally. FBL-3-derived DC can be used as a new type of vaccine. Our results may have important implications for the immunotherapy of leukaemia. Images Figure 3 Figure 4 PMID:9767469

Does cocoa/dark chocolate supplementation have favorable effect on body weight, body mass index and waist circumference? A systematic review, meta-analysis and dose-response of randomized clinical trials.

PubMed

Kord-Varkaneh, Hamed; Ghaedi, Ehsan; Nazary-Vanani, Ali; Mohammadi, Hamed; Shab-Bidar, Sakineh

2018-03-19

Cocoa and dark chocolate (DC) have been reported to be effective for health promotion; however the exact effect of cocoa/DC on anthropometric measures have not been yet defined. A comprehensive search to identify randomized clinical trials investigating the impact of cocoa/DC on body weight, body mass index (BMI) and waist circumference (WC) was performed up to December 2017. A meta-analysis of eligible studies was performed using random effects model to estimate pooled effect size. Fractional polynominal modeling was used to explore dose-response relationships. A total of 35 RCTs investigated the effects of cocoa/DC on weight, BMI and WC were included. Meta-analysis did not suggest any significant effect of cocoa/DC supplementation on body weight (-0.108 kg, 95% CI -0.262, 0.046 P = 0.168), BMI (-0.014 kg/m 2 95% CI -0.105, 0.077, P: 0.759,) and WC (0.025 cm 95% CI -0.083, 0.129, P = 0.640). Subgroup analysis revealed that that weight and BMI were reduced with cocoa/DC supplementation ≥ 30 g chocolate per day in trials between 4-8 weeks. Cocoa/DC consumption resulted in WC reduction in non-linear fashion (r = 0.042, P-nonlinearity = 0.008). Cocoa/DC supplementation does not reduce anthropometric measures significantly. However subgroup analysis regarding dose (≥ 30 g/day) and duration (between 4 to 8 weeks) revealed significant reduction of body weight and BMI.

Millivolt-scale DC shifts in the human scalp EEG: evidence for a nonneuronal generator.

PubMed

Voipio, Juha; Tallgren, Pekka; Heinonen, Erkki; Vanhatalo, Sampsa; Kaila, Kai

2003-04-01

Slow shifts in the human scalp-recorded EEG, including those related to changes in brain CO(2) levels, have been generally assumed to result from changes in the level of tonic excitation of apical dendrites of cortical pyramidal neurons. We readdressed this issue using DC-EEG shifts elicited in healthy adult subjects by hypo- or hypercapnia. A 3-min period of hyperventilation resulted in a prompt negative shift with a rate of up to 10 microV/s at the vertex (Cz) and an extremely steep dependence (up to 100 microV/mmHg) on the end-tidal Pco(2). This shift had a maximum of up to -2 mV at Cz versus the temporal derivations (T3/T4). Hyperventilation-like breathing of 5% CO(2)-95% O(2), which does not lead to a significant hypocapnia, resulted in a near-complete block of the negative DC shift at Cz. Hypoventilation, or breathing 5% CO(2) in air at normal respiratory rate, induced a positive shift. The high amplitude of the voltage gradients on the scalp induced by hyperventilation is not consistent with a neuronal origin. Instead, the present data suggest that they are generated by extracortical volume currents driven by a Pco(2)-dependent potential difference across epithelia separating the cerebrospinal fluid and blood. Since changes in respiratory patterns and, hence, in the level of brain Pco(2), are likely to occur under a number of experimental conditions in which slow EEG responses have been reported (e.g., attention shifts, preparatory states, epileptic seizures, and hypoxic episodes), the present results call for a thorough reexamination of the mechanisms underlying scalp-recorded DC-EEG responses.

[Analysis and characterization of Belamcanda chinensis with space mutagenesis breeding by X-ray fluorescence analysis and X-ray diffraction].

PubMed

Guan, Ying; Ding, Xi-Feng; Wang, Wen-Jing; Guo, Xi-Hua; Zhu, Yan-Ying

2008-02-01

The contents of various elements in the fourth generation Belamcanda chinensis (L.) DC. with space mutagenesis breeding were analyzed and characterized. X-ray fluorescence spectrum analysis (XRF) and powder X-ray diffraction (PXRD) were applied jointly. It was found that the content of K element in the space flight mutagenesis increases 1.03 and 0.31 times, Mg enhances 1.44 and 0.06 times, but Al reduces 38.5% and 85.5% respectively compared to the contents in the ground group and the comparison group, while those of Ca, Mn and Fe enhance 0.95, 0.30 and 0.29 times respectively contrasted to the ground group. Besides, there was discovered the crystal of whewellite in the Belamcanda chinensis (L.) DC. and the content in the ground group is less than that of the outer space and the outer space group, which in turn is less than that of the comparison group. It is concluded that the contents of mineral elements indispensable to body in the space group are closer or superior to the comparison, group as compared to the ground group. In the present paper, a quick and simple appraising method is offered, which may be of great significance to the popularization of the planting outer space Chinese traditional medicine to filtrate more excellent breed and set up norm of quality appraisal.

Cloning, characterization, and expression of xyloglucan endotransglucosylase/hydrolase and expansin genes associated with petal growth and development during carnation flower opening

PubMed Central

Harada, Taro; Torii, Yuka; Morita, Shigeto; Onodera, Reiko; Hara, Yoshinao; Yokoyama, Ryusuke; Nishitani, Kazuhiko; Satoh, Shigeru

2011-01-01

Growth of petal cells is a basis for expansion and morphogenesis (outward bending) of petals during opening of carnation flowers (Dianthus caryophyllus L.). Petal growth progressed through elongation in the early stage, expansion with outward bending in the middle stage, and expansion of the whole area in the late stage of flower opening. In the present study, four cDNAs encoding xyloglucan endotransglucosylase/hydrolase (XTH) (DcXTH1–DcXTH4) and three cDNAs encoding expansin (DcEXPA1–DcEXPA3) were cloned from petals of opening carnation flowers and characterized. Real-time reverse transcription-PCR analyses showed that transcript levels of XTH and expansin genes accumulated differently in floral and vegetative tissues of carnation plants with opening flowers, indicating regulated expression of these genes. DcXTH2 and DcXTH3 transcripts were detected in large quantities in petals as compared with other tissues. DcEXPA1 and DcEXPA2 transcripts were markedly accumulated in petals of opening flowers. The action of XTH in growing petal tissues was confirmed by in situ staining of xyloglucan endotransglucosylase (XET) activity using a rhodamine-labelled xyloglucan nonasaccharide as a substrate. Based on the present findings, it is suggested that two XTH genes (DcXTH2 and DcXTH3) and two expansin genes (DcEXPA1 and DcEXPA2) are associated with petal growth and development during carnation flower opening. PMID:20959626

Silicon nitride directional coupler interferometer for surface sensing

NASA Astrophysics Data System (ADS)

Okubo, Kyohei; Uchiyamada, Ken; Asakawa, Kiyoshi; Suzuki, Hiroaki

2017-01-01

A silicon nitride directional coupler (DC) used to create a biosensing device is presented. The DC detects changes in the refractive index of the cladding (nclad) as changes in the relative output intensity. The DC length (L), nclad-dependent sensitivities of the DC, and preferred dimensions of the single-mode DC waveguides are obtained through numerical simulations. The performance of the DC is evaluated through end-fire coupling measurements. The intensities measured after varying the nclad using air, water, and glycerol solutions agree well with the fitting for a wide range of L values between 60 and 600 μm, i.e., corresponding to 6 to 60 times the coupling length. The bulk refractive index sensitivity was investigated using glycerol solutions of different concentrations and was found to be 18.9 optical intensity units per refractive index unit (OIU/RIU). Biotin/streptavidin bindings were detected with a sensitivity of 60 OIU/RIU and a detection limit of 0.13 μM, suggesting the feasibility of the DC for immunosensing.

The influence of cooking procedures on doxycycline concentration in contaminated eggs.

PubMed

Gajda, Anna; Bladek, Tomasz; Gbylik-Sikorska, Malgorzata; Posyniak, Andrzej

2017-04-15

Doxycycline (DC) is forbidden compound in laying hens. Most information about drug residues in eggs concern their concentrations in raw matrix and the data about the influence of cooking on antibiotics residues in eggs are limited. Thus, the residues concentration of DC in eggs after different cooking methods was investigated. Analyses of DC were assayed by liquid chromatography - tandem mass spectrometry method. The stability of DC in eggs were depended upon the type and time of cooking procedure. By microwaving DC was reduced most effective with concentrations decreased by 53% and 50.3% after 4min of microwaving without cover and microwaving with cover, respectively. In fried eggs, DC was reduced by 39.8% in 6min. By the boiling cooking, the smallest reduction was observed with the concentration decreased by 29.8% after 8min. The obtained results show that ordinary cooking does not eliminate the all DC residues present in eggs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Glass transition and relaxation processes of nanocomposite polymer electrolytes.

PubMed

Money, Benson K; Hariharan, K; Swenson, Jan

2012-07-05

This study focus on the effect of δ-Al(2)O(3) nanofillers on the dc-conductivity, glass transition, and dielectric relaxations in the polymer electrolyte (PEO)(4):LiClO(4). The results show that there are three dielectric relaxation processes, α, β, and γ, in the systems, although the structural α-relaxation is hidden in the strong conductivity contribution and could therefore not be directly observed. However, by comparing an enhanced dc-conductivity, by approximately 2 orders of magnitude with 4 wt % δ-Al(2)O(3) added, with a decrease in calorimetric glass transition temperature, we are able to conclude that the dc-conductivity is directly coupled to the hidden α-relaxation, even in the presence of nanofillers (at least in the case of δ-Al(2)O(3) nanofillers at concentrations up to 4 wt %). This filler induced speeding up of the segmental polymer dynamics, i.e., the α-relaxation, can be explained by the nonattractive nature of the polymer-filler interactions, which enhance the "free volume" and mobility of polymer segments in the vicinity of filler surfaces.

Novel Electrically Tunable Microwave Solenoid Inductor and Compact Phase Shifter Utilizing Permaloy and PZT Thin Films

DOE PAGES

Wang, Tengxing; Jiang, Wei; Divan, Ralu; ...

2017-08-03

A Permalloy (Py) thin film enabled tunable 3-D solenoid inductor is designed and fabricated. The special configuration of magnetic core is discussed and by selectively patterning Py thin film, the proposed tunable inductor can work at frequency up to several GHz range. The inductance of the solenoid inductor can be electrically tuned by dc current and the tunability is above 10%. Utilizing the implemented Py enabled tunable solenoid inductor and Lead Zirconate Titanate (PZT) thin film enabled metal-insulator-metal (MIM) capacitor, a compact fully electrically tunable lumped elements phase shifter is achieved. The tunable phase shifter has both inductive and capacitivemore » tunability and the dual tunability significantly improves the tuning range and design flexibility. Moreover, the dual tunability is able to retain the equivalent characteristic impedance of the device in the process of the phase being tuned. Here, the phase of the device can be tuned by fully electrical methods and when dc current and dc voltage are provided, the length normalized phase tunability is up to 210°/cm« less

Direct observation of the core/double-shell architecture of intense dual-mode luminescent tetragonal bipyramidal nanophosphors

NASA Astrophysics Data System (ADS)

Kim, Su Yeon; Jeong, Jong Seok; Mkhoyan, K. Andre; Jang, Ho Seong

2016-05-01

Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce3+ to Tb3+ under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm-2 and 73.0 +/- 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered.Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce3+ to Tb3+ under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm-2 and 73.0 +/- 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered. Electronic supplementary information (ESI) available: XRD patterns, PL and PLE spectra, SEM and HR-TEM images, PL decay times, photographs showing the transparent nanophosphor solutions and their dual-mode luminescence, and additional EDX data. See DOI: 10.1039/c5nr05722a

The ac and dc performance of polymeric insulating materials under accelerated aging in a fog chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorur, R.S.; Cherney, E.A.; Hackam, R.

1988-10-01

The paper presents the results of the dc performance of polymeric insulating materials in a fog chamber. The materials evaluated in fog produced from low (250 ..mu..S/cm) and high (1000 ..mu..S/cm) conductivity water include cylindrical rod samples of high temperature vulcanized (HTV) silicone rubber and ethylene propylene diene monomer (EPDM) rubber containing various amounts of either alumina trihydrate (ATH) or silica fillers, or both. Comparison is made of material performance obtained with ac which was reported in an earlier study. In both low and high conductivity fog, the time to failure with ac and +dc was very similar, but amore » reduction by a factor of about four was observed in the time to failure with -dc. For both ac and dc, silicone rubber performed better than EPDM samples in low conductivity fog, while the order of performance was reversed in high conductivity fog. A theoretical model to determine the effect of dry band discharges on material is presented. Good agreement of the predicted behavior of materials with the experimental findings is shown.« less

A simplified version of the total Kjeldahl nitrogen method using an ammonia extraction ultrasound-assisted purge-and-trap system and ion chromatography for analyses of geological samples.

PubMed

Pontes, Fernanda V M; Carneiro, Manuel C; Vaitsman, Delmo S; da Rocha, Genilda P; da Silva, Lílian I D; Neto, Arnaldo A; Monteiro, Maria Inês C

2009-01-26

The total Kjeldahl nitrogen (TKN) method was simplified by using a manifold connected to a purge-and-trap system immersed into an ultrasonic (US) bath for simultaneous ammonia (NH(3)) extraction from many previously digested samples. Then, ammonia was collected in an acidic solution, converted to ammonium (NH(4)(+)), and finally determined by ion chromatography method. Some variables were optimized, such as ultrasonic irradiation power and frequency, ultrasound-assisted NH(3) extraction time, NH(4)(+) mass and sulfuric acid concentration added to the NH(3) collector flask. Recovery tests revealed no changes in the pH values and no conversion of NH(4)(+) into other nitrogen species during the irradiation of NH(4)Cl solutions with 25 or 40 kHz ultrasonic waves for up to 20 min. Sediment and oil free sandstone samples and soil certified reference materials (NCS DC 73319, NCS DC 73321 and NCS DC 73326) with different total nitrogen concentrations were analysed. The proposed method is faster, simpler and more sensitive than the classical Kjeldahl steam distillation method. The time for NH(3) extraction by the US-assisted purge-and-trap system (20 min) was half of that by the Kjeldahl steam distillation (40 min) for 10 previously digested samples. The detection limit was 9 microg g(-1)N, while for the Kjeldahl classical/indophenol method was 58 microg g(-1)N. Precision was always better than 13%. In the proposed method, carcinogenic reagents are not used, contrarily to the indophenol method. Furthermore, the proposed method can be adapted for fixed-NH(4)(+) determination.

Prognostic value of changes in brain tissue oxygen pressure before and after decompressive craniectomy following severe traumatic brain injury.

PubMed

Lubillo, Santiago T; Parrilla, Dácil M; Blanco, José; Morera, Jesús; Dominguez, Jaime; Belmonte, Felipe; López, Patricia; Molina, Ismael; Ruiz, Candelaria; Clemente, Francisco J; Godoy, Daniel A

2018-05-01

OBJECTIVE In severe traumatic brain injury (TBI), the effects of decompressive craniectomy (DC) on brain tissue oxygen pressure (PbtO 2 ) and outcome are unclear. The authors aimed to investigate whether changes in PbtO 2 after DC could be used as an independent prognostic factor. METHODS The authors conducted a retrospective, observational study at 2 university hospital ICUs. The study included 42 patients who were admitted with isolated moderate or severe TBI and underwent intracranial pressure (ICP) and PbtO 2 monitoring before and after DC. The indication for DC was an ICP higher than 25 mm Hg refractory to first-tier medical treatment. Patients who underwent primary DC for mass lesion evacuation were excluded. However, patients were included who had undergone previous surgery as long as it was not a craniectomy. ICP/PbtO 2 monitoring probes were located in an apparently normal area of the most damaged hemisphere based on cranial CT scanning findings. PbtO 2 values were routinely recorded hourly before and after DC, but for comparisons the authors used the first PbtO 2 value on ICU admission and the number of hours with PbtO 2 < 15 mm Hg before DC, as well as the mean PbtO 2 every 6 hours during 24 hours pre- and post-DC. The end point of the study was the 6-month Glasgow Outcome Scale; a score of 4 or 5 was considered a favorable outcome, whereas a score of 1-3 was considered an unfavorable outcome. RESULTS Of the 42 patients included, 26 underwent unilateral DC and 16 bilateral DC. The median Glasgow Coma Scale score at the scene of the accident or at the initial hospital before the patient was transferred to one of the 2 ICUs was 7 (interquartile range [IQR] 4-14). The median time from admission to DC was 49 hours (IQR 7-301 hours). Before DC, the median ICP and PbtO 2 at 6 hours were 35 mm Hg (IQR 28-51 mm Hg) and 11.4 mm Hg (IQR 3-26 mm Hg), respectively. In patients with favorable outcome, PbtO 2 at ICU admission was higher and the percentage of time that pre-DC PbtO 2 was < 15 mm Hg was lower (19 ± 4.5 mm Hg and 18.25% ± 21.9%, respectively; n = 28) than in those with unfavorable outcome (12.8 ± 5.2 mm Hg [p < 0.001] and 59.58% ± 38.8% [p < 0.001], respectively; n = 14). There were no significant differences in outcomes according to the mean PbtO 2 values only during the last 12 hours before DC, the hours of refractory intracranial hypertension, the timing of DC from admission, or the presence/absence of previous surgery. In contrast, there were significant differences in PbtO 2 values during the 12- to 24-hour period before DC. In most patients, PbtO 2 increased during the 24 hours after DC but these changes were more pronounced in patients with favorable outcome than in those with unfavorable outcome (28.6 ± 8.5 mm Hg vs 17.2 ± 5.9 mm Hg, p < 0.0001; respectively). The areas under the curve for the mean PbtO 2 values at 12 and 24 hours after DC were 0.878 (95% CI 0.75-1, p < 0.0001) and 0.865 (95% CI 0.73-1, p < 0.0001), respectively. CONCLUSIONS The authors' findings suggest that changes in PbtO 2 before and after DC, measured with probes in healthy-appearing areas of the most damaged hemisphere, have independent prognostic value for the 6-month outcome in TBI patients.

Anti-control of chaos of single time-scale brushless DC motor.

PubMed

Ge, Zheng-Ming; Chang, Ching-Ming; Chen, Yen-Sheng

2006-09-15

Anti-control of chaos of single time-scale brushless DC motors is studied in this paper. In order to analyse a variety of periodic and chaotic phenomena, we employ several numerical techniques such as phase portraits, bifurcation diagrams and Lyapunov exponents. Anti-control of chaos can be achieved by adding an external constant term or an external periodic term.

The application of the analog signal to discrete time interval converter to the signal conditioner power supplies

NASA Technical Reports Server (NTRS)

Schoenfeld, A. D.; Yu, Y.

1973-01-01

The Analog Signal to Discrete Time Interval Converter microminiaturized module was utilized to control the signal conditioner power supplies. The multi-loop control provides outstanding static and dynamic performance characteristics, exceeding those generally associated with single-loop regulators. Eight converter boards, each containing three independent dc to dc converter, were built, tested, and delivered.

An adaptable multiple power source for mass spectrometry and other scientific instruments.

PubMed

Lin, T-Y; Anderson, G A; Norheim, R V; Prost, S A; LaMarche, B L; Leach, F E; Auberry, K J; Smith, R D; Koppenaal, D W; Robinson, E W; Paša-Tolić, L

2015-09-01

An Adaptable Multiple Power Source (AMPS) system has been designed and constructed. The AMPS system can provide up to 16 direct current (DC) (±400 V; 5 mA), 4 radio frequency (RF) (two 500 VPP sinusoidal signals each, 0.5-5 MHz) channels, 2 high voltage sources (±6 kV), and one ∼40 W, 250 °C temperature-regulated heater. The system is controlled by a microcontroller, capable of communicating with its front panel or a computer. It can assign not only pre-saved fixed DC and RF signals but also profiled DC voltages. The AMPS system is capable of driving many mass spectrometry components and ancillary devices and can be adapted to other instrumentation/engineering projects.

Terahertz and infrared transmission of an organic/inorganic hybrid thermoelectric material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heyman, J. N., E-mail: heyman@macalester.edu; Alebachew, B. A.; Kaminski, Z. S.

2014-04-07

We report terahertz and infrared transmission measurements of a high-performance thermoelectric material containing tellurium nanowires in a conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) matrix. The DC electrical conductivity of the hybrid material (41 S/cm) is approximately one hundred times that of pure PEDOT:PSS and more than 400 times that of a film of pure tellurium nanowires, while the terahertz-frequency (THz) conductivity of PEDOT:PSS and the hybrid material are comparable at f ∼ 2THz. A frequency-dependent conductivity model indicates that the increased DC conductivity of the hybrid material results from an increase in the DC charge mobility rather than in the free charge density. We suggestmore » that the increased DC conductivity of the hybrid material results from an increase in linkage between PEDOT domains by the tellurium nanowires.« less

Digitally gain controlled linear high voltage amplifier for laboratory applications.

PubMed

Koçum, C

2011-08-01

The design of a digitally gain controlled high-voltage non-inverting bipolar linear amplifier is presented. This cost efficient and relatively simple circuit has stable operation range from dc to 90 kHz under the load of 10 kΩ and 39 pF. The amplifier can swing up to 360 V(pp) under these conditions and it has 2.5 μs rise time. The gain can be changed by the aid of JFETs. The amplifiers have been realized using a combination of operational amplifiers and high-voltage discrete bipolar junction transistors. The circuit details and performance characteristics are discussed.

Fundamental Understanding of the Impact High Pulsed Power Loading has on a MicroGrid’s DC or AC Bus

DTIC Science & Technology

2013-06-12

The lithium - ion battery module is made up of two parallel stacks of six 4.1 V GALA 27 Ah cells providing a 54 Ah, 24.4 V source voltage with a -3.0...100 Ah Gel cell lead-acid (left) and 54 Ah GALA lithium - ion battery (right) energy storage modules. During each experiment, the output of the buck...batteries are used. Because the lithium - ion battery ESR is lower than that of the lead-acid, it contributes more to the rise time of the discharge

High speed, long distance, data transmission multiplexing circuit

DOEpatents

Mariotti, Razvan

1991-01-01

A high speed serial data transmission multiplexing circuit, which is operable to accurately transmit data over long distances (up to 3 Km), and to multiplex, select and continuously display real time analog signals in a bandwidth from DC to 100 Khz. The circuit is made fault tolerant by use of a programmable flywheel algorithm, which enables the circuit to tolerate one transmission error before losing synchronization of the transmitted frames of data. A method of encoding and framing captured and transmitted data is used which has a low overhead and prevents some particular transmitted data patterns from locking an included detector/decoder circuit.

Sky with Ocean Joined, Presented at Proceedings of the Sesquicentennial Symposia Held at Washington, DC on 5-8 December 1980

DTIC Science & Technology

1983-12-01

did much to encourage others to pursue pure research while he personally worked on practical research projects. Recognition ot Maury’s contributions ...tune trails ami retaining tubs > vthe real ’ »e ball is at "he top ot the st.itt . I he\\ worked the tune ball concept into tu > ornamentation ot the...City d is shown in Figure 33. The structure at the top is ■ the Titanic Memorial Light and Time Ball Tow- * cr, shown in close-up in Figure 34, md it

Design of BLDCM emulator for transmission control units

NASA Astrophysics Data System (ADS)

Liu, Chang; He, Yongyi; Zhang, Bodong

2018-04-01

According to the testing requirements of the transmission control unit, a brushless DC motor emulating system is designed based on motor simulation and power hardware-in-the-loop. The discrete motor model is established and a real-time numerical method is designed to solve the motor states. The motor emulator directly interacts with power stage of the transmission control unit using a power-efficient circuit topology and is compatible with sensor-less control. Experiments on a laboratory prototype help to verify that the system can emulate the real motor currents and voltages whenever the motor is starting up or suddenly loaded.

Impact of Doctor Car with Mobile Cloud ECG in reducing door-to- balloon time of Japanese ST-elevation myocardial infarction patients.

PubMed

Takeuchi, Ichiro; Fujita, Hideo; Yanagisawa, Tomoyoshi; Sato, Nobuhiro; Mizutani, Tomohiro; Hattori, Jun; Asakuma, Sadataka; Yamaya, Tatsuhiro; Inagaki, Taito; Kataoka, Yuichi; Ohe, Kazuhiko; Ako, Junya; Asari, Yasushi

2015-01-01

Early reperfusion by percutaneous coronary intervention (PCI) is the current standard therapy for ST-elevation myocardial infarction (STEMI). To achieve better prognoses for these patients, reducing the door-to-balloon time is essential. As we reported previously, the Kitasato University Hospital Doctor Car (DC), an ambulance with a physician on board, is equipped with a novel mobile cloud 12-lead ECG system. Between September 2011 and August 2013, there were 260 emergency dispatches of our Doctor Car, of which 55 were for suspected acute myocardial infarction with chest pain and cold sweat. Among these 55 calls, 32 patients received emergent PCI due to STEMI (DC Group). We compared their data with those of 76 STEMI patients who were transported directly to our hospital by ambulance around the same period (Non-DC Group). There were no differences in patient age, gender, underlying diseases, or Killip classification between the two groups. The door-to-balloon time in the DC group was 56.1 ± 13.7 minutes and 74.0 ± 14.1 minutes in the Non-DC Group (P < 0.0001). Maximum levels of CPK were 2899 ± 308 and 2876 ± 269 IU/L (P = 0.703), and those of CK-MB were 292 ± 360 and 295 ± 284 ng/mL (P = 0.423), respectively, in the 2 groups. The Doctor Car system with the Mobile Cloud ECG was useful for reducing the door-to-balloon time.

Spontaneous cortical DC-potential shifts: modulation stereotypy; relationships to higher EEG-frequencies.

PubMed

Etlinger, S C; Guttmann, G; Bauer, H

1986-07-01

A description of scalp-recorded, spontaneous, cerebral DC-potential shifts is given independent of other variables (shift stereotypy), in relationship to higher frequencies (theta, alpha 1, alpha 2: 4-13 Hz) and as analyzed pairwise across the median sagittal line (Fz, Cz, Pz) separately according to frequency and condition (relaxation and moderate mental load). Spontaneous DC-shifts are shown to behave unpredictably. Whether measured jointly (up to triads) or as dyad and triad context entropy, the frontal DC-shifts are calculated as being random, whereby their definition as such within the context of the Principle Component Analysis is supported by the analysis of longitudinal registrations. Cross-correlation analysis of the cerebral slow potential's relationship to each of the higher frequencies (theta, alpha 1, alpha 2) reveals it to be highly independent, the highest correlation accounting for merely 11% of the common variance, the average being 9% (R congruent to 0.3). By matching the conjoint activity of the DC-potential between Fz-Cz, Cz-Pz, and Fz-Pz to that of theta, alpha 1, alpha 2 at the same paired sites, the DC-activity is shown to be operating at higher levels of synchronous activity than the higher frequencies, regardless of pairing and/or condition, although the general level of synchronous activity (DC, theta, alpha 1, alpha 2) is remarkably high along the median sagittal line, 75% of the correlation averages of all analysis-pairings being above 0.60.

System-level considerations for the front-end readout ASIC in the CBM experiment from the power supply perspective

NASA Astrophysics Data System (ADS)

Kasinski, K.; Koczon, P.; Ayet, S.; Löchner, S.; Schmidt, C. J.

2017-03-01

New fixed target experiments using high intensity beams with energy up to 10 AGeV from the SIS100 synchrotron presently being constructed at FAIR/GSI are under preparation. Most of the readout electronics and power supplies are expected to be exposed to a very high flux of nuclear reaction products and have to be radiation tolerant up to 3 MRad (TID) and sustain up to 1014/cm2 of 1 MeV neutron equivalent in their life time. Moreover, the mostly minimum ionising particles under investigation leave very little signal in the sensors. Therefore very low noise level amplitude measurements are required by the front-end electronics for effective tracking. Sensor and interconnecting micro-cable capacitance and series resistance in conjunction with intrinsic noise of the charge sensitive amplifier are dominant noise sources in the system. However, the single-ended architecture of the amplifiers employed for the charge processing channels implies a potential problem with noise contributions from power supply sources. Strict system-level constraints leave very little freedom in selecting a power supply structure optimal with respect to: power efficiency, cooling capabilities and power density on modules, but also noise injection to the front-end via the power supply lines. Design of the power supply and distribution system of the Silicon Tracking System in the CBM experiment together with details on the front-end ASICs (STS -XYTER2) and measurement results of power supply and conditioning electronics (selected DC/DC converter and LDO regulators) are presented.

Improving Health, Social Welfare, and Human Development Through Women’s Empowerment in Developing Countries: The 2016 Girl Up Leadership Summit, Washington, DC, USA

PubMed Central

Mendoza, Janel

2016-01-01

The United Nations Foundation’s Girl Up campaign, an initiative dedicated to promoting the health, education, and leadership of adolescent girls in developing communities around the world, hosted its annual Girl Up Leadership Summit in Washington, DC from July 11-13, 2016. The summit welcomed more than 275 girl empowerment and women empowerment proponents to take part in leadership training, listen to and learn from influential figures like United Nations Deputy High Commissioner for Human Rights Kate Gilmore and Treasurer of the United States Rosie Rios, as well as engage in an official lobby day in the nation’s capital. Topics discussed at the summit ranged from the issue of child marriage and sexual and reproductive health rights to intersectional feminism and the importance of the next generation of global girl advocates. The purpose and, later on, achievement of the conference was the development of such leaders and Girl Up representatives. Summit attendee and Girl Up Campus Leader Janel Mendoza shares her experience as a longstanding Girl Up supporter and reflects on the preeminent conversations held during and following the summit. PMID:28058195

Improving Health, Social Welfare, and Human Development Through Women's Empowerment in Developing Countries: The 2016 Girl Up Leadership Summit, Washington, DC, USA.

PubMed

Mendoza, Janel

2016-01-01

The United Nations Foundation's Girl Up campaign, an initiative dedicated to promoting the health, education, and leadership of adolescent girls in developing communities around the world, hosted its annual Girl Up Leadership Summit in Washington, DC from July 11-13, 2016. The summit welcomed more than 275 girl empowerment and women empowerment proponents to take part in leadership training, listen to and learn from influential figures like United Nations Deputy High Commissioner for Human Rights Kate Gilmore and Treasurer of the United States Rosie Rios, as well as engage in an official lobby day in the nation's capital. Topics discussed at the summit ranged from the issue of child marriage and sexual and reproductive health rights to intersectional feminism and the importance of the next generation of global girl advocates. The purpose and, later on, achievement of the conference was the development of such leaders and Girl Up representatives. Summit attendee and Girl Up Campus Leader Janel Mendoza shares her experience as a longstanding Girl Up supporter and reflects on the preeminent conversations held during and following the summit.

Ultrafast excited-state dynamics of RNA and DNA C tracts

NASA Astrophysics Data System (ADS)

Cohen, Boiko; Larson, Matthew H.; Kohler, Bern

2008-06-01

The excited-state dynamics of the RNA homopolymer of cytosine and of the 18-mer (dC) 18 were studied by steady-state and time-resolved absorption and emission spectroscopy. At pH 6.8, excitation of poly(rC) by a femtosecond UV pump pulse produces excited states that decay up to one order of magnitude more slowly than the excited states formed in the mononucleotide cytidine 5'-monophosphate under the same conditions. Even slower relaxation is observed for the hemiprotonated, self-associated form of poly(rC), which is stable at acidic pH. Transient absorption and time-resolved fluorescence signals for (dC) 18 at pH 6.8 are similar to ones observed for poly(rC) near pH 4, indicating that hemiprotonated structures are found in DNA C tracts at neutral pH. In both systems, there is evidence for two kinds of emitting states with lifetimes of ˜100 ps and slightly more than 1 ns. The former states are responsible for the bulk of emission from the hemiprotonated structures. Evidence suggests that slow electronic relaxation in these self-complexes is the result of vertical base stacking. The similar signals from RNA and DNA C tracts suggest a common base-stacked structure, which may be identical with that of i-motif DNA.

Kilovolt dc solid state remote power controller development

NASA Technical Reports Server (NTRS)

Mitchell, J. T.

1982-01-01

The experience gained in developing and applying solid state power controller (SSPC) technology at high voltage dc (HVDC) potentials and power levels of up to 25 kilowatts is summarized. The HVDC switching devices, power switching concepts, drive circuits, and very fast acting overcurrent protection circuits were analyzed. A 25A bipolar breadboard with Darlington connected switching transistor was built. Fault testing at 900 volts was included. A bipolar transistor packaged breadboard design was developed. Power MOSFET remote power controller (RPC) was designed.

Rupture models with dynamically determined breakdown displacement

USGS Publications Warehouse

Andrews, D.J.

2004-01-01

The critical breakdown displacement, Dc, in which friction drops to its sliding value, can be made dependent on event size by specifying friction to be a function of variables other than slip. Two such friction laws are examined here. The first is designed to achieve accuracy and smoothness in discrete numerical calculations. Consistent resolution throughout an evolving rupture is achieved by specifying friction as a function of elapsed time after peak stress is reached. Such a time-weakening model produces Dc and fracture energy proportional to the square root of distance rupture has propagated in the case of uniform stress drop. The second friction law is more physically motivated. Energy loss in a damage zone outside the slip zone has the effect of increasing Dc and limiting peak slip velocity (Andrews, 1976). This article demonstrates a converse effect, that artificially limiting slip velocity on a fault in an elastic medium has a toughening effect, increasing fracture energy and Dc proportionally to rupture propagation distance in the case of uniform stress drop. Both the time-weakening and the velocity-toughening models can be used in calculations with heterogeneous stress drop.

Model predictive controller design for boost DC-DC converter using T-S fuzzy cost function

NASA Astrophysics Data System (ADS)

Seo, Sang-Wha; Kim, Yong; Choi, Han Ho

2017-11-01

This paper proposes a Takagi-Sugeno (T-S) fuzzy method to select cost function weights of finite control set model predictive DC-DC converter control algorithms. The proposed method updates the cost function weights at every sample time by using T-S type fuzzy rules derived from the common optimal control engineering knowledge that a state or input variable with an excessively large magnitude can be penalised by increasing the weight corresponding to the variable. The best control input is determined via the online optimisation of the T-S fuzzy cost function for all the possible control input sequences. This paper implements the proposed model predictive control algorithm in real time on a Texas Instruments TMS320F28335 floating-point Digital Signal Processor (DSP). Some experimental results are given to illuminate the practicality and effectiveness of the proposed control system under several operating conditions. The results verify that our method can yield not only good transient and steady-state responses (fast recovery time, small overshoot, zero steady-state error, etc.) but also insensitiveness to abrupt load or input voltage parameter variations.

Haemoglobin discordances in twins: due to differences in timing of cord clamping?

PubMed

Verbeek, Lianne; Zhao, Depeng P; Middeldorp, Johanna M; Oepkes, Dick; Hooper, Stuart B; Te Pas, Arjan B; Lopriore, Enrico

2017-07-01

Our objective was to study the differences in haemoglobin (Hb) at birth in dichorionic (DC) versus monochorionic (MC) twins in relation to birth order and mode of delivery. All consecutive DC twin pregnancies and uncomplicated MC twin pregnancies with two live-born twins delivered at our centre were included in this retrospective cohort study. Hb levels at birth and on day 2 were evaluated in association with birth order and mode of delivery. The occurrence of polycythaemia (venous haematocrit >65%) was also recorded. A total of 300 DC and 290 MC twin pairs were included. In DC and MC twins delivered vaginally, second-born twins had a higher Hb level at birth compared with their co-twin (mean Hb level 16.7 vs 15.9 g/dL (p<0.01) in DC twins and 17.8 vs 16.1 g/dL (p<0.01) in MC twins). In twins delivered through caesarean section, no intertwin differences in Hb levels were detected. Polycythaemia occurred significantly more often in second-born twins compared with first-born twins delivered vaginally: 10 (5%) vs 2 (1%) (p=0.02) in DC twins and 20 (12%) vs 2 (1%) (p<0.01) in MC twins. Second-born DC and MC twins delivered vaginally have higher Hb levels at birth compared with first-born twins. Intertwin Hb differences in MC twins may partly be related to blood transfusion through the vascular anastomoses. Since DC twins do not have anastomoses, other factors may lead to Hb differences, including differences in timing of umbilical cord clamping. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Solid state remote power controllers for 120 VDC power systems

NASA Technical Reports Server (NTRS)

Sundberg, G. R.; Baker, D. E.

1975-01-01

Solid state remote power controllers can be applied to any dc power system up to 120 Vdc and distribute power up to 3.6 kW per hour. Devices have demonstrated total electrical efficiencies of 98.5 percent to 99.0 percent at rated load currents.

A new protocol for the propagation of dendritic cells from rat bone marrow using recombinant GM-CSF, and their quantification using the mAb OX-62

PubMed Central

Chen-Woan, M.; Delaney, C.P.; Fournier, V.; Wakizaka, Y.; Murase, N.; Fung, J.; Starzl, T.E.; Demetris, A.J.

2010-01-01

Bone marrow (BM)-derived dendritic cells (DC) are the most potent known antigen (Ag) presenting cell in vivo and in vitro. Detailed analysis of their properties and mechanisms of action requires an ability to produce large numbers of DC. Although DC have been isolated from several rat tissues, including BM, the yield is uniformly low. We describe a simple method for the propagation of large numbers of DC from rat BM and document cell yield with the rat DC marker, OX-62. After depletion of plastic-adherent and Fc+ cells by panning on dishes coated with normal serum, residual BM cells were cultured in gelatin coated flasks using murine rGM-CSF supplemented medium. Prior to analysis, non-adherent cells were re-depleted of contaminating Fc+ cells. Propagation of DC was monitored by double staining for FACS analysis (major histocompatibility complex (MHC) class II+/OX-62+, OX-19−). Functional assay, morphological analysis and evaluation of homing patterns of cultured cells revealed typical DC characteristics. MHC class II and OX-62 antigen expression increased with time in culture and correlated with allostimulatory ability. DC yield increased until day 7, when 3.3 × 106 DC were obtained from an initial 3 × 108 unfractionated BM cells. Significant numbers of DC can be generated from rat BM using these simple methods. This should permit analysis and manipulation of rat DC functions in vivo and in vitro. PMID:7836778

The influence of superimposed DC current on electrical and spectroscopic characteristics of HiPIMS discharge

NASA Astrophysics Data System (ADS)

Zuo, Xiao; Chen, Rende; Liu, Jingzhou; Ke, Peiling; Wang, Aiying

2018-01-01

The electrical characteristics and spectroscopic properties have been comprehensively investigated in a DC superimposed high power impulse magnetron sputtering (DC-HiPIMS) deposition system in this paper. The influence of superimposed DC current on the variation of target and substrate current waveforms, active species and electron temperatures with pulse voltages are focused. The peak target currents in DC-HiPIMS are lower than in HiPIMS. The time scales of the two main discharge processes like ionization and gas rarefaction in DC-HiPIMS are analyzed. When the pulse voltage is higher than 600 V, the gas rarefaction effect becomes apparent. Overall, the ionization process is found to be dominant in the initial ˜100 μs during each pulse. The active species of Ar and Cr in DC-HiPIMS are higher than in HiPIMS unless that the pulse voltage reaches 900 V. However, the ionization degree in HiPIMS exceeds that in DC-HiPIMS at around 600 V. The electron temperature calculated by modified Boltzmann plot method based on corona model has a precipitous increase from 0.87 to 25.0 eV in HiPIMS, but varies mildly after the introduction of the superimposed DC current. Additionally, the current from plasma flowing to the substrate is improved when a DC current is superimposed with HiPIMS.

Bidirectional dc-to-dc Power Converter

NASA Technical Reports Server (NTRS)

Griesbach, C. R.

1986-01-01

Solid-state, series-resonant converter uses high-voltage thyristors. Converter used either to convert high-voltage, low-current dc power to lowvoltage, high current power or reverse. Taking advantage of newly-available high-voltage thyristors to provide better reliability and efficiency than traditional converters that use vacuum tubes as power switches. New converter essentially maintenance free and provides greatly increased mean time between failures. Attractive in industrial applications whether or not bidirectional capability is required.

Simulations of Field-Emission Electron Beams from CNT Cathodes in RF Photoinjectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihalcea, Daniel; Faillace, Luigi; Panuganti, Harsha

2015-06-01

Average field emission currents of up to 700 mA were produced by Carbon Nano Tube (CNT) cathodes in a 1.3 GHz RF gun at Fermilab High Brightness Electron Source Lab. (HBESL). The CNT cathodes were manufactured at Xintek and tested under DC conditions at RadiaBeam. The electron beam intensity as well as the other beam properties are directly related to the time-dependent electric field at the cathode and the geometry of the RF gun. This report focuses on simulations of the electron beam generated through field-emission and the results are compared with experimental measurements. These simulations were performed with themore » time-dependent Particle In Cell (PIC) code WARP.« less

Possibility designing half-wave and full-wave molecular rectifiers by using single benzene molecule

NASA Astrophysics Data System (ADS)

Abbas, Mohammed A.; Hanoon, Falah H.; Al-Badry, Lafy F.

2018-02-01

This work focused on possibility designing half-wave and full-wave molecular rectifiers by using single and two benzene rings, respectively. The benzene rings were threaded by a magnetic flux that changes over time. The quantum interference effect was considered as the basic idea in the rectification action, the para and meta configurations were investigated. All the calculations are performed by using steady-state theoretical model, which is based on the time-dependent Hamiltonian model. The electrical conductance and the electric current are considered as DC output signals of half-wave and full-wave molecular rectifiers. The finding in this work opens up the exciting potential to use these molecular rectifiers in molecular electronics.

7 CFR 1724.51 - Design requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... control house, seismic considerations, corrosion, grounding, protective relaying, and AC and DC auxiliary... plant including plant buildings, the generator step-up transformer, and the transmission switchyard at a...

Bond performance of "Touch and Cure" adhesives on resin core systems.

PubMed

Kadowaki, Yoshitaka; Kakuda, Shinichi; Kawano, Shimpei; Katsumata, Aiichiro; Ting, Shihchun; Hoshika, Shuhei; Ikeda, Takatsumi; Tanaka, Toru; Carvalho, Ricardo Marinsde; Sano, Hidehiko

2016-01-01

The purpose of this study was to compare the micro-tensile bond strength (µTBS) of three resin core composites to dentin and to examine the bonded interface of the composites. One experimental TDK-03(TD) and, two commercial, DC core Automix One (DC) and Unifil core EM(UN) were used. Flat dentin surfaces of human molars were exposed using #600 SiC paper and bonded with the respective adhesive of each system. After bonding, the composites were built up on the surfaces and cured under two conditions: "light condition" or "dark condition". µTBSs (MPa) in the light condition were: TD; 60.02±17.08, DC; 38.21±13.70, and UN; 29.50±9.71; in the dark condition: TD; 54.62±17.11, DC; 8.40±4.81, and UN; 9.47±6.56. Dark curing negatively affected the bond strength of the two commercial resin-core materials. The experimental material was not affected by the curing conditions.

Inflammatory Flt3L is essential to mobilize dendritic cells and for T cell responses during Plasmodium infection

PubMed Central

Guermonprez, Pierre; Helft, Julie; Claser, Carla; Deroubaix, Stephanie; Karanje, Henry; Gazumyan, Anna; Darrasse-Jeze, Guillaume; Telerman, Stephanie B.; Breton, Gaëlle; Schreiber, Heidi A.; Frias-Staheli, Natalia; Billerbeck, Eva; Dorner, Marcus; Rice, Charles M.; Ploss, Alexander; Klein, Florian; Swiecki, Melissa; Colonna, Marco; Kamphorst, Alice O.; Meredith, Matthew; Niec, Rachel; Takacs, Constantin; Mikhail, Fadi; Hari, Aswin; Bosque, David; Eisenreich, Tom; Merad, Miriam; Shi, Yan; Ginhoux, Florent; Rénia, Laurent; Urban, Britta C.; Nussenzweig, Michel C.

2014-01-01

Summary Innate sensing mechanisms trigger a variety of humoral and cellular events that are essential to adaptive immune responses. Here we describe an innate sensing pathway triggered by Plasmodium infection that regulates dendritic cell (DC) homeostasis and adaptive immunity via Flt3L release. Plasmodium-induced Flt3L release requires toll-like receptor activation and type I interferon production. We find that type I interferon supports the up-regulation of xanthine dehydrogenase, which metabolizes the xanthine accumulating in infected erythrocytes to uric acid. Uric acid crystals trigger mast cells to release soluble Flt3L from a pre-synthesized membrane-associated precursor. During infection Flt3L preferentially stimulates expansion of the CD8α+/CD103+ DC subset or its BDCA3+ human DC equivalent and has a significant impact on the magnitude of T cell activation, mostly in the CD8+ compartment. Our findings highlight a new mechanism that regulates DC homeostasis and T cell responses to infection. PMID:23685841

Input current shaped ac-to-dc converters

NASA Technical Reports Server (NTRS)

1985-01-01

Input current shaping techniques for ac-to-dc converters were investigated. Input frequencies much higher than normal, up to 20 kHz were emphasized. Several methods of shaping the input current waveform in ac-to-dc converters were reviewed. The simplest method is the LC filter following the rectifier. The next simplest method is the resistor emulation approach in which the inductor size is determined by the converter switching frequency and not by the line input frequency. Other methods require complicated switch drive algorithms to construct the input current waveshape. For a high-frequency line input, on the order of 20 kHz, the simple LC cannot be discarded so peremptorily, since the inductor size can be compared with that for the resistor emulation method. In fact, since a dc regulator will normally be required after the filter anyway, the total component count is almost the same as for the resistor emulation method, in which the filter is effectively incorporated into the regulator.

Experimental Analysis of Voltage Drop Compensation in a DC Electrified Railway by Introducing an Energy Storage System Incorporating EDLCs

NASA Astrophysics Data System (ADS)

Konishi, Takeshi; Hase, Shin-Ichi; Nakamichi, Yoshinobu; Nara, Hidetaka; Uemura, Tadashi

Interest has been shown in the concept of an energy storage system aimed at leveling load and improving energy efficiency by charging during vehicle regeneration and discharging during running. Such a system represents an efficient countermeasure against pantograph point voltage drop, power load fluctuation and regenerative power loss. We selected an EDLC model as an energy storage medium and a step-up/step-down chopper as a power converter to exchange power between the storage medium and overhead lines. Basic verification was conducted using a mini-model for DC 400V, demonstrating characteristics suitable for its use as an energy storage system. Based on these results, an energy storage system was built for DC 600V and a verification test conducted in conjunction with the Enoshima Electric Railway Co. Ltd. This paper gives its experimental analysis of voltage drop compensation in a DC electrified railway and some discussions based on the test.

Battery charging and discharging research based on the interactive technology of smart grid and electric vehicle

NASA Astrophysics Data System (ADS)

Zhang, Mingyang

2018-06-01

To further study the bidirectional flow problem of V2G (Vehicle to Grid) charge and discharge motor, the mathematical model of AC/DC converter and bi-directional DC/DC converter was established. Then, lithium battery was chosen as the battery of electric vehicle and its mathematical model was established. In order to improve the service life of lithium battery, bidirectional DC/DC converter adopted constant current and constant voltage control strategy. In the initial stage of charging, constant current charging was adopted with current single closed loop control. After reaching a certain value, voltage was switched to constant voltage charging controlled by voltage and current. Subsequently, the V2G system simulation model was built in MATLAB/Simulink. The simulation results verified the correctness of the control strategy and showed that when charging, constant current and constant voltage charging was achieved, the grid side voltage and current were in the same phase, and the power factor was about 1. When discharging, the constant current discharge was applied, and the grid voltage and current phase difference was r. To sum up, the simulation results are correct and helpful.

A Reduced-Intensity Conditioning Regimen for Patients with Dyskeratosis Congenita Undergoing Hematopoietic Stem Cell Transplantation.

PubMed

Nelson, Adam S; Marsh, Rebecca A; Myers, Kasiani C; Davies, Stella M; Jodele, Sonata; O'Brien, Tracey A; Mehta, Parinda A

2016-05-01

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative option for progressive marrow failure, myelodysplastic syndrome, or leukemia associated with dyskeratosis congenita (DC). HSCT for DC is limited by a high incidence of treatment-related mortality, thought to be related to underlying chromosomal instability and sensitivity to chemotherapy and radiation. We report our experience in 7 patients with DC who underwent allogeneic transplantation using a reduced-intensity conditioning (RIC) preparative regimen that contained chemotherapy only (no radiation). This RIC regimen, designed specifically for patients with DC, contained alemtuzumab, fludarabine, and melphalan (with melphalan at 50% reduced dosing), with the goal of decreasing toxicity and improving outcome. All 7 patients engrafted, with none developing mixed chimerism or rejection. Two patients experienced acute graft-versus-host disease (GVHD) and 1 went on to develop limited chronic GVHD of the skin. Five patients remain alive and well at a median follow-up of 44 months (range, 14 to 57 months). We conclude that a radiation-free RIC regimen results in durable engraftment, acceptable toxicity, and improved overall survival in patients with DC undergoing allogeneic HSCT. Published by Elsevier Inc.

Digital Control Technologies for Modular DC-DC Converters

NASA Technical Reports Server (NTRS)

Button, Robert M.; Kascak, Peter E.; Lebron-Velilla, Ramon

2002-01-01

Recent trends in aerospace Power Management and Distribution (PMAD) systems focus on using commercial off-the-shelf (COTS) components as standard building blocks. This move to more modular designs has been driven by a desire to reduce costs and development times, but is also due to the impressive power density and efficiency numbers achieved by today's commercial DC-DC converters. However, the PMAD designer quickly learns of the hidden "costs" of using COTS converters. The most significant cost is the required addition of external input filters to meet strict electromagnetic interference (MIAMI) requirements for space systems. In fact, the high power density numbers achieved by the commercial manufacturers are greatly due to the lack of necessary input filters included in the COTS module. The NASA Glenn Research Center is currently pursuing a digital control technology that addresses this problem with modular DC-DC converters. This paper presents the digital control technologies that have been developed to greatly reduce the input filter requirements for paralleled, modular DC-DC converters. Initial test result show that the input filter's inductor size was reduced by 75 percent, and the capacitor size was reduced by 94 percent while maintaining the same power quality specifications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, E.R.C. da; Filho, B.J.C.

This paper presents a PWM current clamping circuit for improving a series resonant DC link converter. This circuit is capable of reducing current peaks to about 1.2--1.4 times the DC bias current. When desired, resonant transition creates notches in the dc link current, allowing the converter`s switches to synchronize with external PWM strategy. A regulated DC current source may be obtained--by using a conventional rectifier source--to feed a DC load or a current source inverter. Phase plane approach makes ease the understanding the operation, control and design procedure of the circuit. Another topology is derived and its features compared tomore » the first circuit. Simulation results for the simplified circuit and for a three-phase induction motor driven by such inverter will be presented. Moreover, the principle is corroborated by experimental results.« less

A compact 45 kV curve tracer with picoampere current measurement capability.

PubMed

Sullivan, W W; Mauch, D; Bullick, A; Hettler, C; Neuber, A; Dickens, J

2013-03-01

This paper discusses a compact high voltage curve tracer for high voltage semiconductor device characterization. The system sources up to 3 mA at up to 45 kV in dc conditions. It measures from 328 V to 60 kV with 15 V resolution and from 9.4 pA to 4 mA with 100 fA minimum resolution. Control software for the system is written in Microsoft Visual C# and features real-time measurement control and IV plotting, arc-protection and detection, an electrically isolated universal serial bus interface, and easy data exporting capabilities. The system has survived numerous catastrophic high voltage device-under-test arcing failures with no loss of measurement capability or system damage. Overall sweep times are typically under 2 min, and the curve tracer system was used to characterize the blocking performance of high voltage ceramic capacitors, high voltage silicon carbide photoconductive semiconductor switches, and high voltage coaxial cable.

75 FR 2831 - Airworthiness Directives; McDonnell Douglas Corporation Model DC-10-10, DC-10-10F, and MD-10-10F...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-19

... proposed AD would require a one-time high frequency eddy current inspection of fastener holes for cracks at... high frequency eddy current inspection of fastener holes for cracking at the left and right side wing... of this AD, do a one-time high frequency eddy current inspection for cracking of fastener holes at...

CD4/CD8/Dendritic cell complexes in the spleen: CD8+ T cells can directly bind CD4+ T cells and modulate their response

PubMed Central

Barinov, Aleksandr; Galgano, Alessia; Krenn, Gerald; Tanchot, Corinne; Vasseur, Florence

2017-01-01

CD4+ T cell help to CD8+ T cell responses requires that CD4+ and CD8+ T cells interact with the same antigen presenting dendritic cell (Ag+DC), but it remains controversial whether helper signals are delivered indirectly through a licensed DC and/or involve direct CD4+/CD8+ T cell contacts and/or the formation of ternary complexes. We here describe the first in vivo imaging of the intact spleen, aiming to evaluate the first interactions between antigen-specific CD4+, CD8+ T cells and Ag+DCs. We show that in contrast to CD4+ T cells which form transient contacts with Ag+DC, CD8+ T cells form immediate stable contacts and activate the Ag+DC, acquire fragments of the DC membranes by trogocytosis, leading to their acquisition of some of the DC properties. They express MHC class II, and become able to present the specific Marilyn peptide to naïve Marilyn CD4+ T cells, inducing their extensive division. In vivo, these CD8+ T cells form direct stable contacts with motile naïve CD4+ T cells, recruiting them to Ag+DC binding and to the formation of ternary complexes, where CD4+ and CD8+ T cells interact with the DC and with one another. The presence of CD8+ T cells during in vivo immune responses leads to the early activation and up-regulation of multiple functions by CD4+ T lymphocytes. Thus, while CD4+ T cell help is important to CD8+ T cell responses, CD8+ T cells can interact directly with naïve CD4+ T cells impacting their recruitment and differentiation. PMID:28686740

Effector and regulatory dendritic cells display distinct patterns of miRNA expression.

PubMed

Lombardi, Vincent; Luce, Sonia; Moussu, Hélène; Morizur, Lise; Gueguen, Claire; Neukirch, Catherine; Chollet-Martin, Sylvie; Mascarell, Laurent; Aubier, Michel; Baron-Bodo, Véronique; Moingeon, Philippe

2017-09-01

MicroRNAs (miRNAs) contribute to the regulation of dendritic cell (DC) polarization, thereby influencing the balance of adaptive immune responses. Herein, we studied the expression of miRNAs in polarized DCs and analyzed whether expression of these miRNAs could be associated with allergic rhinitis and allergen immunotherapy (AIT) outcome. Using specific culture conditions, we differentiated immature human monocyte-derived DCs into DC1, DC2, and DCreg subsets (supporting the differentiation of T H 1, T H 2 or regulatory T cells, respectively). Profiling of miRNA expression was performed in these DC subpopulations using microarrays. Levels of miRNAs specific for polarized DCs were then evaluated in a cohort of 58 patients with allergic rhinitis and 25 non-allergic controls, as well as in samples from 30 subjects treated with sublingual grass pollen tablets or placebo for four months. We successfully identified 16 miRNAs differentially regulated between immature DCs, DC1, DC2, and DCreg cells. In allergic rhinoconjunctivitis patients, the expression of two of those miRNAs (miR-132 and miR-155), was down-regulated compared to non-allergic individuals. However, the levels of these miRNAs were not significantly modified following four months of grass pollen immunotherapy. Studying polarized DCs and clinical samples from subjects with or without allergic rhinoconjunctivitis, we demonstrated that the expression of two miRNAs linked to effector DCs (i.e., DC1 and/or DC2 cells), was reduced in the blood of patients with allergic rhinoconjunctivitis. Nevertheless, these miRNAs did not represent relevant biomarkers to predict or follow-up AIT efficacy. © 2017 The Authors. Immunity, Inflammation and Disease Published by John Wiley & Sons Ltd.

Effector and regulatory dendritic cells display distinct patterns of miRNA expression

PubMed Central

Luce, Sonia; Moussu, Hélène; Morizur, Lise; Gueguen, Claire; Neukirch, Catherine; Chollet‐Martin, Sylvie; Mascarell, Laurent; Aubier, Michel; Baron‐Bodo, Véronique; Moingeon, Philippe

2017-01-01

Abstract Introduction MicroRNAs (miRNAs) contribute to the regulation of dendritic cell (DC) polarization, thereby influencing the balance of adaptive immune responses. Herein, we studied the expression of miRNAs in polarized DCs and analyzed whether expression of these miRNAs could be associated with allergic rhinitis and allergen immunotherapy (AIT) outcome. Method Using specific culture conditions, we differentiated immature human monocyte‐derived DCs into DC1, DC2, and DCreg subsets (supporting the differentiation of TH1, TH2 or regulatory T cells, respectively). Profiling of miRNA expression was performed in these DC subpopulations using microarrays. Levels of miRNAs specific for polarized DCs were then evaluated in a cohort of 58 patients with allergic rhinitis and 25 non‐allergic controls, as well as in samples from 30 subjects treated with sublingual grass pollen tablets or placebo for four months. Results We successfully identified 16 miRNAs differentially regulated between immature DCs, DC1, DC2, and DCreg cells. In allergic rhinoconjunctivitis patients, the expression of two of those miRNAs (miR‐132 and miR‐155), was down‐regulated compared to non‐allergic individuals. However, the levels of these miRNAs were not significantly modified following four months of grass pollen immunotherapy. Conclusions Studying polarized DCs and clinical samples from subjects with or without allergic rhinoconjunctivitis, we demonstrated that the expression of two miRNAs linked to effector DCs (i.e., DC1 and/or DC2 cells), was reduced in the blood of patients with allergic rhinoconjunctivitis. Nevertheless, these miRNAs did not represent relevant biomarkers to predict or follow‐up AIT efficacy. PMID:28497578

Comparative study of serum/plasma glycation and lipid peroxidation of young patients with type 1 diabetes mellitus in relation to glycemic compensation and the occurrence of diabetic complications.

PubMed

Kostolanska, J; Jakus, V; Barak, L; Stanikova, A; Waczulikova, I

2010-01-01

We tried to investigate whether the AGEs in serum and lipoperoxides (LPO) monitoring were suitable for an early prediction of diabetic complications (DC) development in diabetological practice. We wanted to find whether it is better to divide the file according to the presence of DC or in terms of glycemic compensation in this study. 79 diabetic patients with duration of disease for at least 5 years were divided in respect to DC presence/absence and also to long-time glycemic compensation. HbA1c was measured by LPLC in fair capillary blood, s-AGEs were estimated spectrofluorimetrically and LPO iodimetrically and spectrophotometrically in serum. HbA1c, s-AGEs and LPO were significantly higher in the group with DC (+DC) vs. controls and also in -DC vs. controls. HbA1c and s-AGEs were significantly higher in +DC vs. patients without DC (-DC). HbA1c, s-AGEs and LPO were significantly higher in patients with poor glycemic compensation (PGC) compared to controls and HbA1c and LPO in patients with good glycemic compensation (GGC) compared to controls. HbA1c and s-AGEs were significantly higher in PGC vs. GGC. In the group of GGC we have found interesting significant correlations of HbA1c with HDL (r=0.451, p<0.05) and with LDL (r=-0.450, p<0.05). Our findings suggest that the monitoring of s-AGEs in poorly compensated diabetic patients and LPO in all may be very useful to recognize the risk of complications. The dividing of patient file in terms of long time glycemic compensation is more reliable for research of this issue (Tab. 3, Fig. 6, Ref. 41). Full Text in free PDF www.bmj.sk.

Dual and self-curing potential of self-adhesive resin cements as thin films.

PubMed

Moraes, R R; Boscato, N; Jardim, P S; Schneider, L F J

2011-01-01

In this study, the dual- and self-curing potential of self-adhesive resin cements (SARCs) as thin, clinically-relevant cement films was investigated. The SARCs tested were: BisCem (BSC; Bisco), Maxcem Elite (MXE; Kerr), RelyX Unicem clicker (UNI; 3M ESPE), seT capsule (SET; SDI), and SmartCem 2 (SC2; Dentsply Caulk). The conventional cement RelyX ARC (3M ESPE) was tested as a reference. The degree of conversion (DC) as a function of time was evaluated by real-time Fourier transform infrared spectroscopy with an attenuated total reflectance (ATR) device. The cements were either photoactivated for 40 seconds (dual-cure mode) or not photoactivated (self-cure mode). The cement film thickness was 50 ± 10 μm. The DC (%) was evaluated 1, 5, 10, 15, 20, 25, and 30 minutes after placing the cement on the ATR cell. Data for DC as a function of time were analyzed by two-way repeated measures analysis of variance (ANOVA). DC values at 30 minutes for the self- and dual-cure modes were submitted to one-way ANOVA. Post hoc comparisons were performed using the Student-Newman-Keuls test (p<0.05). The rate and the extent of conversion were lower for the SARCs compared with the conventional cement. Means ± standard deviations (SD) for the dual-cure mode at 30 minutes were: 75 ± 5 (ARC)a, 73 ± 8 (SET)a, 61 ± 4 (MXE)b, 51 ± 9 (BSC)c, 51 ± 4 (UNI)c, and 48 ± 3 (SC2)c, while in the self-cure mode means and SD were 62 ± 6 (ARC)a, 54 ± 3 (MXE)b, 40 ± 6 (SC2)c, 35 ± 2 (UNI)c, 35 ± 3 (SET)c, and 11 ± 3 (BSC)d. The DC for the dual-cure mode was generally higher than the self-cure, irrespective of the time. Discrepancies in DC between the dual- and self-cure modes from 11% to 79% were observed. In conclusion, SARCs may present slower rate of polymerization and lower final DC than conventional resin cements, in either the dual- or self-cure mode.

A Global Circuit Diagram to Contrast the Behavior of the DC and AC Global Circuits

NASA Astrophysics Data System (ADS)

Williams, E.; Boldi, R. A.; Markson, R. J.

2017-12-01

The Earth-ionosphere cavity is home to both the classical DC and the AC (Schumann resonances) global circuits. The predominant source for the AC global circuit is lightning, but the sources for the DC global circuit source remains controversial. Separate measurements over many years have shown that the amplitude variation of global lightning and the AC global circuit is about twice that of the DC global circuit on both the diurnal and annual time scales. A global diagram is used to shed further light on this result and to explore the co-variation of the two global circuits. Actual measurements of the ionospheric potential (Vi) are plotted against the simultaneous global lightning flash rate F. The latter estimates are drawn from a global climatology of LIS/OTD satellite observations (Cecil et al., 2014) giving flash rate as a function of both Day of Year and UT time, and are used as best guesses for F at the time of the Vi observations. A least-squares linear fit through the data points on this diagram show a zero-flash-rate intercept for Vi that is more than half of the mean Vi ( 250 kV). This result suggests that electrified shower clouds (without lightning), possibly supplemented by convective transport of positive space charge in the marine boundary layer, are playing a greater role in driving the DC global circuit than previously suspected.

DC Linked Hybrid Generation System with an Energy Storage Device including a Photo-Voltaic Generation and a Gas Engine Cogeneration for Residential Houses

NASA Astrophysics Data System (ADS)

Lung, Chienru; Miyake, Shota; Kakigano, Hiroaki; Miura, Yushi; Ise, Toshifumi; Momose, Toshinari; Hayakawa, Hideki

For the past few years, a hybrid generation system including solar panel and gas cogeneration is being used for residential houses. Solar panels can generate electronic power at daytime; meanwhile, it cannot generate electronic power at night time. But the power consumption of residential houses usually peaks in the evening. The gas engine cogeneration system can generate electronic power without such a restriction, and it also can generate heat power to warm up house or to produce hot water. In this paper, we propose the solar panel and gas engine co-generation hybrid system with an energy storage device that is combined by dc bus. If a black out occurs, the system still can supply electronic power for special house loads. We propose the control scheme for the system which are related with the charging level of the energy storage device, the voltage of the utility grid which can be applied both grid connected and stand alone operation. Finally, we carried out some experiments to demonstrate the system operation and calculation for loss estimation.

Analysis of the new polarimeter for the Marshall Space Flight Center vector magnetograph

NASA Technical Reports Server (NTRS)

West, E. A.

1985-01-01

The magnetograph was upgraded in both electronic control of the magnetograph hardware and in the polarization optics. The problems associated with the orignal polarimeter were: (1) field of view errors associated with the natural birefringence of the KD*P crystals; (2.) KD*P electrode failure due to the halfwave dc voltage required in one of the operational sequences; and (3) breakdown of the retardation properties of some KD*Ps when exposed to a zero to halfwave modulation (DC) scheme. The new polarimeter gives up the flexibility provided by two variable waveplates to adjust the retardances of the optics for a particular polarization measurement, but solves the problems associated with the original polarimeter. With the addition of the quartz quarterwave plates, a new optical alignment was developed to allow the remaining KD*P to correct for errors in the waveplates. The new optical alignment of the polarimeter is prescribed. The various sources of error, and how those errors are minimized so that the magnetograph can look at the transverse field in real time are discussed.

Simulation of continuously logical base cells (CL BC) with advanced functions for analog-to-digital converters and image processors

NASA Astrophysics Data System (ADS)

Krasilenko, Vladimir G.; Lazarev, Alexander A.; Nikitovich, Diana V.

2017-10-01

The paper considers results of design and modeling of continuously logical base cells (CL BC) based on current mirrors (CM) with functions of preliminary analogue and subsequent analogue-digital processing for creating sensor multichannel analog-to-digital converters (SMC ADCs) and image processors (IP). For such with vector or matrix parallel inputs-outputs IP and SMC ADCs it is needed active basic photosensitive cells with an extended electronic circuit, which are considered in paper. Such basic cells and ADCs based on them have a number of advantages: high speed and reliability, simplicity, small power consumption, high integration level for linear and matrix structures. We show design of the CL BC and ADC of photocurrents and their various possible implementations and its simulations. We consider CL BC for methods of selection and rank preprocessing and linear array of ADCs with conversion to binary codes and Gray codes. In contrast to our previous works here we will dwell more on analogue preprocessing schemes for signals of neighboring cells. Let us show how the introduction of simple nodes based on current mirrors extends the range of functions performed by the image processor. Each channel of the structure consists of several digital-analog cells (DC) on 15-35 CMOS. The amount of DC does not exceed the number of digits of the formed code, and for an iteration type, only one cell of DC, complemented by the device of selection and holding (SHD), is required. One channel of ADC with iteration is based on one DC-(G) and SHD, and it has only 35 CMOS transistors. In such ADCs easily parallel code can be realized and also serial-parallel output code. The circuits and simulation results of their design with OrCAD are shown. The supply voltage of the DC is 1.8÷3.3V, the range of an input photocurrent is 0.1÷24μA, the transformation time is 20÷30nS at 6-8 bit binary or Gray codes. The general power consumption of the ADC with iteration is only 50÷100μW, if the maximum input current is 4μA. Such simple structure of linear array of ADCs with low power consumption and supply voltage 3.3V, and at the same time with good dynamic characteristics (frequency of digitization even for 1.5μm CMOS-technologies is 40÷50 MHz, and can be increased up to 10 times) and accuracy characteristics are show. The SMC ADCs based on CL BC and CM opens new prospects for realization of linear and matrix IP and photo-electronic structures with matrix operands, which are necessary for neural networks, digital optoelectronic processors, neural-fuzzy controllers.

Triple Hybrid Energy Harvesting Interface Electronics

NASA Astrophysics Data System (ADS)

Uluşan, H.; Chamanian, S.; Pathirana, W. M. P. R.; Zorlu, Ö.; Muhtaroğlu, A.; Külah, H.

2016-11-01

This study presents a novel triple hybrid system that combines simultaneously generated power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters for a relatively high power supply capability. In the proposed solution each harvesting source utilizes a distinct power management circuit that generates a DC voltage suitable for combining the three parallel supplies. The circuits are designed and implemented in 180 nm standard CMOS technology, and are terminated with a schottky diode to avoid reverse current flow. The harvested AC signal from the EM harvester is rectified with a self-powered AC-DC doubler, which utilizes active diode structures to minimize the forward- bias voltage drop. The PZT interface electronics utilizes a negative voltage converter as the first stage, followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The ultra-low voltage DC power harvested by the TE generator is stepped up through a charge-pump driven by an LC oscillator with fully- integrated center-tapped differential inductors. Test results indicate that hybrid energy harvesting circuit provides more than 1 V output for load resistances higher than 100 kΩ (10 μW) where the stand-alone harvesting circuits are not able to reach 1 V output. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.

[Dendritic cell-based therapeutic cancer vaccines].

PubMed

Rizzo, Manglio; Alaniz, Laura; Mazzolini, Guillermo D

In recent years immunotherapy has revolutionized the treatment of patients with advanced cancer. The increased knowledge in the tumor immune-biology has allowed developing rational treatments by manipulation of the immune system with significant clinical impact. This rapid development has significantly changed the prognosis of many tumors without treatment options up to date. Other strategies have explored the use of therapeutic vaccines based on dendritic cells (DC) by inducing antitumor immunity. DC are cells of hematopoietic origin, constitutively expressing molecules capable to present antigens, that are functionally the most potent inducers of the activation and proliferation of antigen specific T lymphocytes. The CD8+ T cells proliferate and acquire cytotoxic capacity after recognizing their specific antigen presented on the surface of DC, although only some types of DC can present antigens internalized from outside the cell to precursors of cytotoxic T lymphocytes (this function is called cross-presentation) requiring translocation mechanisms of complex antigens. The induction of an effective adaptive immune response is considered a good option given its specificity, and prolonged duration of response. The DC, thanks to its particular ability of antigen presentation and lymphocyte stimulation, are able to reverse the poor antitumor immune response experienced by patients with cancer. The DC can be obtained from various sources, using different protocols to generate differentiation and maturation, and are administered by various routes such as subcutaneous, intravenous or intranodal. The wide variety of protocols resulted in heterogeneous clinical responses.

Expression of decoy receptor 3 in kidneys is associated with allograft survival after kidney transplant rejection.

PubMed

Weng, Shuo-Chun; Shu, Kuo-Hsiung; Wu, Ming-Ju; Wen, Mei-Chin; Hsieh, Shie-Liang; Chen, Nien-Jung; Tarng, Der-Cherng

2015-09-03

Decoy receptor 3 (DcR3) expression in kidneys has been shown to predict progression of chronic kidney disease. We prospectively investigated a cohort comprising 96 renal transplant recipients (RTRs) undergoing graft kidney biopsies. Computer-assisted quantitative immunohistochemical staining value of DcR3 in renal tubular epithelial cells (RTECs) was used to determine the predictive role of DcR3 in kidney disease progression. The primary end point was doubling of serum creatinine and/or graft failure. A multivariate Cox proportional hazards model was used to assess the risk of DcR3 expression in rejected kidney grafts toward the renal end point. In total, RTRs with kidney allograft rejection were evaluated and the median follow-up was 30.9 months. The greater expression of DcR3 immunoreactivity in RTECs was correlated with a higher rate of the histopathological concordance of acute T cell-mediated rejection. Compared with 65 non-progressors, 31 progressors had higher DcR3 expression (HDE) regardless of the traditional risk factors. Cox regression analysis showed HDE was significantly associated with the risk of renal end point with a hazard ratio of 3.19 (95% confidence interval, 1.40 to 7.27; P = 0.006) after adjusting for other variables. In repetitive biopsies, HDE in tissue showed rapid kidney disease progression due to persistent inflammation.

The Market Response to the Sioux City DC-10 Crash.

PubMed

Barnett, Arnold; Menighetti, John; Prete, Matthew

1992-03-01

The 1989 DC-10 crash at Sioux City, Iowa presented a rare instance in which a potential threat to safety was both (i) intensely publicized over a short period and (ii) also amenable to the unobtrusive measurement of the market reaction it evoked. As such, it allowed a useful case study of the extent and duration of behavior change caused by a frightening event. Using reservations data from travel agencies in five states, this paper estimates the short-term effects of the Sioux City crash on passenger willingness to fly the DC-10. The data suggest that, in the first few weeks after the crash, more than one third of travelers who would normally have booked DC-10 flights chose instead to fly other aircraft. Within 2 months of the disaster, however, DC-10 bookings rebounded to within 10% of the level that would have been expected had the Sioux City crash not occurred. At no time, apparently, did the airlines that operate DC-10s use their "yield-management" computer pricing systems unofficially to lower DC-10 fares relative to those on other types of plane.

P/N In(Al) GaAs multijunction laser power converters

NASA Technical Reports Server (NTRS)

Wojtczuk, Steven; Parados, Themis; Walker, Gilbert

1994-01-01

Eight In(AI)GaAs PN junctions grown epitaxially on the semi-insulating wafer were monolithically integrated in series to boost the approximately 0.4V photovoltage per typical In(Al)GaAs junction to over 3 volts for the 1 sq cm laser power converted (LPC) chip. Advantages of multijunction LCP designs include the need for less circuitry for power reconditioning and the potential for lower I(sup 2)R power loss. As an example, these LPC's have a responsivity of approximately 1 amp/watt. With a single junction LPC, 100 watts/sq cm incident power would lead to about 100 A/sq cm short-circuit current at approximately 0.4V open-cicuit voltage. One disadvantage is the large current would lead to a large I(sup 2)R loss which would lower the fill factor so that 40 watts/sq cm output would not be obtained. Another is that few circuits are designed to work at 0.4 volts, so DC-DC power conversion circuitry would be necessary to raise the voltage to a reasonable level. The multijunction LPC being developed in this program is a step toward solving these problems. In the above example, an eight-junction LPC would have eight times the voltage, approximately 3V, so that DC-DC power conversion may not be needed in many instances. In addition, the multijunction LPC would have 1/8 the current of a single-junction LPC, for only 1/64 the I(sup 2)R loss if the series resistance is the same. Working monolithic multijunction laser power converters (LPC's) were made in two different compositions of the In(x)Al(y)Ga(1-x-y)As semiconductor alloy, In(0.53)Ga(0.47)As (0.74 eV) and In(0.5)Al(0.1)Ga(0.4)As (0.87 eV). The final 0.8 sq cm LPC's had output voltages of about 3 volts and output currents up to about one-half amp. Maximum 1.3 micron power conversion efficiencies were approximately 22 percent. One key advantage of multijunction LPC's is that they have higher output voltages, so that less DC-DC power conversion circuitry is needed in applications.

Matrix metalloproteinase triggered size-shrinkable gelatin-gold fabricated nanoparticles for tumor microenvironment sensitive penetration and diagnosis of glioma

NASA Astrophysics Data System (ADS)

Ruan, Shaobo; He, Qin; Gao, Huile

2015-05-01

To improve glioma targeting delivery efficiency and to monitor drug delivery and treatment outcome, a novel tumor microenvironment sensitive size-shrinkable theranostic system was constructed and evaluated. The G-AuNPs-DC-RRGD system was constructed by fabricating small sized gold nanoparticles (AuNPs) onto matrix metalloproteinase-2 (MMP-2) degradable gelatin nanoparticles (GNPs), doxorubicin (DOX) and Cy5.5 were decorated onto AuNPs through a hydrazone bond to enable the system with pH triggered cargoes release, and RRGD, a tandem peptide of RGD and octarginine was surface-modified onto the system to enable it with glioma active targeting ability. In vitro, the size of G-AuNPs-DC-RRGD could effectively shrink from 188.2 nm to 55.9 nm after incubation with MMP-2, while DOX and Cy5.5 were released in a pH dependent manner. Cellular uptake demonstrated that G-AuNPs-DC-RRGD could be effectively taken up by cells with higher intensity than G-AuNPs-DC-PEG. A study of tumor spheroids further demonstrated that the particles with smaller size showed better penetration ability, while RRGD modification could further improve permeability. In vivo, G-AuNPs-DC-RRGD displayed the best glioma targeting and accumulation efficiency, with good colocalization with neovessels. Cy5.5 also was colocalized well with DOX, indicating that Cy5.5 could be used for imaging of DOX delivery.To improve glioma targeting delivery efficiency and to monitor drug delivery and treatment outcome, a novel tumor microenvironment sensitive size-shrinkable theranostic system was constructed and evaluated. The G-AuNPs-DC-RRGD system was constructed by fabricating small sized gold nanoparticles (AuNPs) onto matrix metalloproteinase-2 (MMP-2) degradable gelatin nanoparticles (GNPs), doxorubicin (DOX) and Cy5.5 were decorated onto AuNPs through a hydrazone bond to enable the system with pH triggered cargoes release, and RRGD, a tandem peptide of RGD and octarginine was surface-modified onto the system to enable it with glioma active targeting ability. In vitro, the size of G-AuNPs-DC-RRGD could effectively shrink from 188.2 nm to 55.9 nm after incubation with MMP-2, while DOX and Cy5.5 were released in a pH dependent manner. Cellular uptake demonstrated that G-AuNPs-DC-RRGD could be effectively taken up by cells with higher intensity than G-AuNPs-DC-PEG. A study of tumor spheroids further demonstrated that the particles with smaller size showed better penetration ability, while RRGD modification could further improve permeability. In vivo, G-AuNPs-DC-RRGD displayed the best glioma targeting and accumulation efficiency, with good colocalization with neovessels. Cy5.5 also was colocalized well with DOX, indicating that Cy5.5 could be used for imaging of DOX delivery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01408e

Toward a fully integrated neurostimulator with inductive power recovery front-end.

PubMed

Mounaïm, Fayçal; Sawan, Mohamad

2012-08-01

In order to investigate new neurostimulation strategies for micturition recovery in spinal cord injured patients, custom implantable stimulators are required to carry-on chronic animal experiments. However, higher integration of the neurostimulator becomes increasingly necessary for miniaturization purposes, power consumption reduction, and for increasing the number of stimulation channels. As a first step towards total integration, we present in this paper the design of a highly-integrated neurostimulator that can be assembled on a 21-mm diameter printed circuit board. The prototype is based on three custom integrated circuits fabricated in High-Voltage (HV) CMOS technology, and a low-power small-scale commercially available FPGA. Using a step-down approach where the inductive voltage is left free up to 20 V, the inductive power and data recovery front-end is fully integrated. In particular, the front-end includes a bridge rectifier, a 20-V voltage limiter, an adjustable series regulator (5 to 12 V), a switched-capacitor step-down DC/DC converter (1:3, 1:2, or 2:3 ratio), as well as data recovery. Measurements show that the DC/DC converter achieves more than 86% power efficiency while providing around 3.9-V from a 12-V input at 1-mA load, 1:3 conversion ratio, and 50-kHz switching frequency. With such efficiency, the proposed step-down inductive power recovery topology is more advantageous than its conventional step-up counterpart. Experimental results confirm good overall functionality of the system.

Development of electrically conductive-superoleophobic micropillars for reducing surface adhesion of oil at low temperatures

NASA Astrophysics Data System (ADS)

Pan, Zihe; Wang, Tianchang; Zhou, Yikang; Zhao, Boxin

2016-12-01

Electrically conductive and superoleophobic micropillars have been developed through the construction of biomimetic micropillars using Ag-filled epoxy composites and the incorporation of FDTS on the micropillar surface. These micropillars are found to be superoleophobic with an oil contact angle of 140°, demonstrating excellent self-cleaning properties. The conductivity of micropillars allows for the Joule-heating effect to actively reduce the adhesion and even unfreeze the frozen oil droplets by passing electrical current. Electrical resistance of the composite micropillars was modulated by two orders of magnitudes by varying the contents of Ag flakes from 45 wt% to 65 wt%. The effectiveness of conductive micropillars for surface un-freezing was investigated by applying DC current to decrease the adhesion strength of frozen oil droplets on surfaces. The results showed a pronounced reduction of frozen oil adhesion force by 60% when the resistance increased from 7.5 Ω to 877 Ω after applying DC current for 2 min. By continuously applying DC current for 3 min, the frozen oil adhesion decreased to 0.05 N, reaching zero when the surface was heated up to -10 °C after applying DC current for 5 min. In contrast, when the droplet was heated up to -5 °C by hot air, there is still a substantial force of adhesion. The research findings demonstrate the use of constructing conductive-superoleophobic composite micropillars at surface for eliminating the frozen oil from surfaces at low temperatures.

Compatibility of an Ultraselective Microcatheter and Epirubicin Loaded 300-500-μm DC Bead in Ex Vivo Study.

PubMed

Fukuoka, Yasushi; Tanaka, Toshihiro; Nishiofuku, Hideyuki; Sato, Takeshi; Kichikawa, Kimihiko

2015-10-01

The purpose of this study is to examine whether epirubicin loaded DC Bead 300-500 μm in size can pass through a 1.8-Fr ultraselective microcatheter in ex vivo study. Epirubicin (25 mg/1 mL) loaded 100-300 and 300-500 μm DC Bead were tested. Both sizes were diluted 5, 10, and 30 times using contrast material. Ultraselective microcatheter with the outer diameter of 1.8 Fr and the inner diameter of .017 inch (431.8 μm) was used. The diluted DC Bead was injected at a speed of 1 mL/min, and the pressure was continuously measured. The microspheres' shapes after ejection were observed by a stereomicroscope. The maximum pressure of contrast material alone was 8.40 ± 0.21 psi. The maximum pressure in 5, 10, and 30 times dilution groups of 100-300 μm were 9.67 ± 1.18, 9.25 ± 0.25, and 9.71 ± 0.28 psi, respectively, whereas 21.10 ± 10.2, 10.48 ± 2.14, 10.09 ± 0.37 psi, respectively in 300-500 μm groups. The maximum pressure in 5 times dilution group of 300-500 μm was significantly higher than the other groups (P < 0.05). In 300-500 μm, 4 of 10 measurements showed high pressure over 24 psi (the maximum value was 43.5 psi) in 5 times dilution group, whereas in 10 times and 30 times dilution groups, all measurements showed less than 12 psi. No damages of microspheres were found. Epirubicin loaded DC Bead 300-500 μm in size can pass through a 1.8-Fr ultraselective microcatheter. To avoid high resistance due to microspheres' aggregation, dilution more than 10 times is needed.

Evaluation of the CPU time for solving the radiative transfer equation with high-order resolution schemes applying the normalized weighting-factor method

NASA Astrophysics Data System (ADS)

Xamán, J.; Zavala-Guillén, I.; Hernández-López, I.; Uriarte-Flores, J.; Hernández-Pérez, I.; Macías-Melo, E. V.; Aguilar-Castro, K. M.

2018-03-01

In this paper, we evaluated the convergence rate (CPU time) of a new mathematical formulation for the numerical solution of the radiative transfer equation (RTE) with several High-Order (HO) and High-Resolution (HR) schemes. In computational fluid dynamics, this procedure is known as the Normalized Weighting-Factor (NWF) method and it is adopted here. The NWF method is used to incorporate the high-order resolution schemes in the discretized RTE. The NWF method is compared, in terms of computer time needed to obtain a converged solution, with the widely used deferred-correction (DC) technique for the calculations of a two-dimensional cavity with emitting-absorbing-scattering gray media using the discrete ordinates method. Six parameters, viz. the grid size, the order of quadrature, the absorption coefficient, the emissivity of the boundary surface, the under-relaxation factor, and the scattering albedo are considered to evaluate ten schemes. The results showed that using the DC method, in general, the scheme that had the lowest CPU time is the SOU. In contrast, with the results of theDC procedure the CPU time for DIAMOND and QUICK schemes using the NWF method is shown to be, between the 3.8 and 23.1% faster and 12.6 and 56.1% faster, respectively. However, the other schemes are more time consuming when theNWFis used instead of the DC method. Additionally, a second test case was presented and the results showed that depending on the problem under consideration, the NWF procedure may be computationally faster or slower that the DC method. As an example, the CPU time for QUICK and SMART schemes are 61.8 and 203.7%, respectively, slower when the NWF formulation is used for the second test case. Finally, future researches to explore the computational cost of the NWF method in more complex problems are required.

E-beam high voltage switching power supply

DOEpatents

Shimer, D.W.; Lange, A.C.

1996-10-15

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 figs.

E-beam high voltage switching power supply

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1996-01-01

A high-power power supply produces a controllable, constant high voltage put under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

Solid Silicone Elastomer Material(DC745U)-Historical Overview and New Experimental Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz-Acosta, Denisse

2012-08-08

DC745U is a silicone elastomer used in several weapon systems. DC745U is manufactured by Dow Corning and its formulation is proprietary. Risk changes without notification to the customer. {sup 1}H and {sup 29}Si{l_brace}{sup 1}H{r_brace} NMR have previously determined that DC745U contains {approx} 98.5% dimethyl siloxane, {approx}1.5% methyl-phenyl siloxane, and a small amount (<1%) of vinyl siloxane repeat units that are converted to crosslinking sites. The polymer is filled with {approx} 38 wt.% of a mixture of fumed silica and quartz. Some conclusions are: (1) DMA shows that crystallization does have an effect on the mechanical properties of DC745U; (2) DMAmore » shows that the crystallization is time and temperature dependent; (3) Mechanical tests show that DC745U undergo a crystalline transition at temperatures below -50 C; (4) Rate and temperature does not have an effect above crystalline transition; (5) Crystalline transition occurs faster at colder temperatures; (6) The material remains responsive and recovers after warming it to temperature above -40 C; (7) We were able to review all previous historical data on DC745U; (8) Identified specific gaps in materials understanding; (9) Developed design of experiments and testing methods to address gaps associated with post-curing and low temperature mechanical behavior; (10) Resolved questions of post-cure and alleviated concerns associated with low temperature mechanical behavior with soak time and temperature; and (11) This work is relevant to mission-critical programs and for supporting programmatic work for weapon research.« less

Effect of Critical Displacement Parameter on Slip Regime at Subduction Fault

NASA Astrophysics Data System (ADS)

Muldashev, Iskander; Sobolev, Stephan

2016-04-01

It is widely accepted that for the simple fault models value of critical displacement parameter (Dc) in Ruina-Dietrich's rate-and-state friction law is responsible for the transition from stick-slip regime at low Dc to non-seismic creep regime at large Dc. However, neither the value of "transition" Dc parameter nor the character of the transition is known for the realistic subduction zone setting. Here we investigate effect of Dc on regime of slip at subduction faults for two setups, generic model similar to simple shear elastic slider under quasistatic loading and full subduction model with appropriate geometry, stress and temperature distribution similar to the setting at the site of the Great Chile Earthquake of 1960. In our modeling we use finite element numerical technique that employs non-linear elasto-visco-plastic rheology in the entire model domain with rate-and-state plasticity within the fault zone. The model generates spontaneous earthquake sequence. Adaptive time-step integration procedure varies time step from 40 seconds at instability (earthquake), and gradually increases it to 5 years during postseismic relaxation. The technique allows observing the effect of Dc on period, magnitude of earthquakes through the cycles. We demonstrate that our modeling results for the generic model are consistent with the previous theoretical and numeric modeling results. For the full subduction model we obtain transition from non-seismic creep to stick-slip regime at Dc about 20 cm. We will demonstrate and discuss the features of the transition regimes in both generic and realistic subduction models.

The effect of an acute ingestion of Turkish coffee on reaction time and time trial performance.

PubMed

Church, David D; Hoffman, Jay R; LaMonica, Michael B; Riffe, Joshua J; Hoffman, Mattan W; Baker, Kayla M; Varanoske, Alyssa N; Wells, Adam J; Fukuda, David H; Stout, Jeffrey R

2015-01-01

The purpose of this study was to examine the ergogenic benefits of Turkish coffee consumed an hour before exercise. In addition, metabolic, cardiovascular, and subjective measures of energy, focus and alertness were examined in healthy, recreationally active adults who were regular caffeine consumers (>200 mg per day). Twenty males (n = 10) and females (n = 10), age 24.1 ± 2.9 y; height 1.70 ± 0.09 m; body mass 73.0 ± 13.0 kg (mean ± SD), ingested both Turkish coffee [3 mg · kg(-1) BW of caffeine, (TC)], and decaffeinated Turkish coffee (DC) in a double-blind, randomized, cross-over design. Performance measures included a 5 km time trial, upper and lower body reaction to visual stimuli, and multiple object tracking. Plasma caffeine concentrations, blood pressure (BP), heart rate and subjective measures of energy, focus and alertness were assessed at baseline (BL), 30-min following coffee ingestion (30+), prior to endurance exercise (PRE) and immediately-post 5 km (IP). Metabolic measures [VO2, V E , and respiratory exchange rate (RER)] were measured during the 5 km. Plasma caffeine concentrations were significantly greater during TC (p < 0.001) at 30+, PRE, and IP compared to DC. Significantly higher energy levels were reported at 30+ and PRE for TC compared to DC. Upper body reaction performance (p = 0.023) and RER (p = 0.019) were significantly higher for TC (85.1 ± 11.6 "hits," and 0.98 ± 0.05 respectively) compared to DC (81.2 ± 13.7 "hits," and 0.96 ± 0.05, respectively). Although no significant differences (p = 0.192) were observed in 5 km run time, 12 of the 20 subjects ran faster (p = 0.012) during TC (1662 ± 252 s) compared to DC (1743 ± 296 s). Systolic BP was significantly elevated during TC in comparison to DC. No other differences (p > 0.05) were noted in any of the other performance or metabolic measures. Acute ingestion of TC resulted in a significant elevation in plasma caffeine concentrations within 30-min of consumption. TC ingestion resulted in significant performance benefits in reaction time and an increase in subjective feelings of energy in habitual caffeine users. No significant differences were noted in time for the 5 km between trials, however 60 % of the participants performed the 5 km faster during the TC trial and were deemed responders. When comparing TC to DC in responders only, significantly faster times were noted when consuming TC compared to DC. No significant benefits were noted in measures of cognitive function.

Does Competitive Sourcing Really Pay?

DTIC Science & Technology

2007-04-30

Governance by contract: Constitutional vision; Time for reflection and choice (Accepted paper.) Public Contract Law Journal, 33(2), p. 24-29. Washington, DC...Public Contract Law Journal, 33(2), 295-296. Washington, DC: The George Washington University Law School. Retrieved from http://ssrn.com/abstract

Reverted glutathione S-transferase-like genes that influence flower color intensity of carnation (Dianthus caryophyllus L.) originated from excision of a transposable element

PubMed Central

Momose, Masaki; Itoh, Yoshio; Umemoto, Naoyuki; Nakayama, Masayoshi; Ozeki, Yoshihiro

2013-01-01

A glutathione S-transferase-like gene, DcGSTF2, is responsible for carnation (Dianthus caryophyllus L.) flower color intensity. Two defective genes, DcGSTF2mu with a nonsense mutation and DcGSTF2-dTac1 containing a transposable element dTac1, have been characterized in detail in this report. dTac1 is an active element that produces reverted functional genes by excision of the element. A pale-pink cultivar ‘Daisy’ carries both defective genes, whereas a spontaneous deep-colored mutant ‘Daisy-VPR’ lost the element from DcGSTF2-dTac1. This finding confirmed that dTac1 is active and that the resulting reverted gene, DcGSTF2rev1, missing the element is responsible for this color change. Crosses between the pale-colored cultivar ‘06-LA’ and a deep-colored cultivar ‘Spectrum’ produced segregating progeny. Only the deep-colored progeny had DcGSTF2rev2 derived from the ‘Spectrum’ parent, whereas progeny with pale-colored flowers had defective forms from both parents, DcGSTF2mu and DcGSTF2-dTac1. Thus, DcGSTF2rev2 had functional activity and likely originated from excision of dTac1 since there was a footprint sequence at the vacated site of the dTac1 insertion. Characterizing the DcGSTF2 genes in several cultivars revealed that the two functional genes, DcGSTF2rev1 and DcGSTF2rev2, have been used for some time in carnation breeding with the latter in use for more than half a century. PMID:24399917

Reverted glutathione S-transferase-like genes that influence flower color intensity of carnation (Dianthus caryophyllus L.) originated from excision of a transposable element.

PubMed

Momose, Masaki; Itoh, Yoshio; Umemoto, Naoyuki; Nakayama, Masayoshi; Ozeki, Yoshihiro

2013-12-01

A glutathione S-transferase-like gene, DcGSTF2, is responsible for carnation (Dianthus caryophyllus L.) flower color intensity. Two defective genes, DcGSTF2mu with a nonsense mutation and DcGSTF2-dTac1 containing a transposable element dTac1, have been characterized in detail in this report. dTac1 is an active element that produces reverted functional genes by excision of the element. A pale-pink cultivar 'Daisy' carries both defective genes, whereas a spontaneous deep-colored mutant 'Daisy-VPR' lost the element from DcGSTF2-dTac1. This finding confirmed that dTac1 is active and that the resulting reverted gene, DcGSTF2rev1, missing the element is responsible for this color change. Crosses between the pale-colored cultivar '06-LA' and a deep-colored cultivar 'Spectrum' produced segregating progeny. Only the deep-colored progeny had DcGSTF2rev2 derived from the 'Spectrum' parent, whereas progeny with pale-colored flowers had defective forms from both parents, DcGSTF2mu and DcGSTF2-dTac1. Thus, DcGSTF2rev2 had functional activity and likely originated from excision of dTac1 since there was a footprint sequence at the vacated site of the dTac1 insertion. Characterizing the DcGSTF2 genes in several cultivars revealed that the two functional genes, DcGSTF2rev1 and DcGSTF2rev2, have been used for some time in carnation breeding with the latter in use for more than half a century.

Rational design of nanoparticles towards targeting antigen-presenting cells and improved T cell priming.

PubMed

Zupančič, Eva; Curato, Caterina; Paisana, Maria; Rodrigues, Catarina; Porat, Ziv; Viana, Ana S; Afonso, Carlos A M; Pinto, João; Gaspar, Rogério; Moreira, João N; Satchi-Fainaro, Ronit; Jung, Steffen; Florindo, Helena F

2017-07-28

Vaccination is a promising strategy to trigger and boost immune responses against cancer or infectious disease. We have designed, synthesized and characterized aliphatic-polyester (poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NP) to investigate how the nature of protein association (adsorbed versus entrapped) and polymer/surfactant concentrations impact on the generation and modulation of antigen-specific immune responses. The ability of the NP formulations to target dendritic cells (DC), be internalized and activate the T cells was characterized and optimized in vitro and in vivo using markers of DC activation and co-stimulatory molecules. Ovalbumin (OVA) was used as a model antigen in combination with the engraftment of CD4 + and CD8 + T cells, carrying a transgenic OVA-responding T cell receptor (TCR), to trace and characterize the activation of antigen-specific CD4 + and CD8 + lymph node T cells upon NP vaccination. Accordingly, the phenotype and frequency of immune cell stimulation induced by the NP loaded with OVA, isolated or in combination with synthetic unmethylated cytosine-phosphate-guanine (CpG) oligodeoxynucleotide (ODN) motifs, were characterized. DC-NP interactions increased with incubation time, presenting internalization values between 50 and 60% and 30-40%, in vitro and in vivo, respectively. Interestingly, animal immunization with antigen-adsorbed NP up-regulated major histocompatibility complex (MHC) class II (MHCII), while NP entrapping the antigen up-regulated MHCI, suggesting a more efficient cross-presentation. On the other hand, rather surprisingly, the surfactant used in the NP formulation had a major impact on the activation of antigen presenting cells (APC). In fact, DC collected from lymph nodes of animals immunized with NP prepared using poly(vinil alcohol) (PVA), as a surfactant, expressed significantly higher levels of CD86, MHCI and MHCII. In addition, those NP prepared with PVA and co-entrapping OVA and the toll-like receptor (TLR) ligand CpG, induced the most profound antigen-specific T cell response, by both CD4 + and CD8 + T cells, in vivo. Overall, our data reveal the impact of NP composition and surface properties on the type and extension of induced immune responses. Deeper understanding on the NP-immune cell crosstalk can guide the rational development of nano-immunotherapeutic systems with improved and specific therapeutic efficacy and avoiding off-target effects. Copyright © 2017 Elsevier B.V. All rights reserved.

The Washington DC Metro Area Lightning Mapping Array

NASA Technical Reports Server (NTRS)

Krehbiel, Paul; Rison, William; Edens, Harald; OConnor, Nicholas; Aulich, Graydon; Thomas, Ronald; Kieft, Sandra; Goodman, Steven; Blakeslee, Richard; Hall, John;

GaN Microwave DC-DC Converters

NASA Astrophysics Data System (ADS)

Ramos Franco, Ignacio

Increasing the operating frequency of switching converters can have a direct impact in the miniaturization and integration of power converters. The size of energy-storage passive components and the difficulty to integrate them with the rest of the circuitry is a major challenge in the development of a fully integrated power supply on a chip. The work presented in this thesis attempts to address some of the difficulties encountered in the design of high-frequency converters by applying concepts and techniques usually used in the design of high-efficiency power amplifiers and high-efficiency rectifiers at microwave frequencies. The main focus is in the analysis, design, and characterization of dc-dc converters operating at microwave frequencies in the low gigahertz range. The concept of PA-rectifier duality, where a high-efficiency power amplifier operates as a high-efficiency rectifier is investigated through non-linear simulations and experimentally validated. Additionally, the concept of a self-synchronous rectifier, where a transistor rectifier operates synchronously without the need of a RF source or driver is demonstrated. A theoretical analysis of a class-E self-synchronous rectifier is presented and validated through non-linear simulations and experiments. Two GaN class-E2 dc-dc converters operating at a switching frequency of 1 and 1.2 GHz are demonstrated. The converters achieve 80 % and 75 % dc-dc efficiency respectively and are among the highest-frequency and highest-efficiency reported in the literature. The application of the concepts established in the analysis of a self-synchronous rectifier to a power amplifier culminated in the development of an oscillating, self-synchronous class-E 2 dc-dc converter. Finally, a proof-of-concept fully integrated GaN MMIC class-E 2 dc-dc converter switching at 4.6 GHz is demonstrated for the first time to the best of our knowledge. The 3.8 mm x 2.6 mm chip contains distributed inductors and does not require any external components. The maximum measured dc-dc efficiency is approximately 45%.

The accumulation and not the specific activity of telomerase ribonucleoprotein determines telomere maintenance deficiency in X-linked dyskeratosis congenita

PubMed Central

Zeng, Xi-Lei; Thumati, Naresh R.; Fleisig, Helen B.; Hukezalie, Kyle R.; Savage, Sharon A.; Giri, Neelam; Alter, Blanche P.; Wong, Judy M.Y.

2012-01-01

X-linked dyskeratosis congenita (X-DC) is caused by mutations in the housekeeping nucleolar protein dyskerin. Amino acid changes associated with X-DC are remarkably heterogeneous. Peripheral mononuclear blood cells and fibroblasts isolated from X-DC patients harbor lower steady-state telomerase RNA (TER) levels and shorter telomeres than healthy age-matched controls. Previously, we showed that retroviral expression of recombinant TER, together with expression of recombinant telomerase reverse transcriptase, restored telomere maintenance and proliferative capacity in X-DC patient cells. Using rare X-DC isoforms (▵L37 and A386T dyskerin), we showed that telomere maintenance defects observed in X-DC are solely due to decreased steady-state levels of TER. Disease-associated reductions in steady-state TER levels cause deficiencies in telomere maintenance. Here, we confirm these findings in other primary X-DC patient cell lines coding for the most common (A353V dyskerin) and more clinically severe (K314R and A353V dyskerin) X-DC isoforms. Using cell lines derived from these patients, we also examined the steady-state levels of other hinge-ACA motif RNAs and did not find differences in their in vivo accumulations. We show, for the first time, that purified telomerase holoenzyme complexes from different X-DC cells have normal catalytic activity. Our data confirm that dyskerin promotes TER stability in vivo, endorsing the development of TER supplementation strategies for the treatment of X-DC. PMID:22058290

A miniature transformer/dc-dc converter for implantable medical devices

NASA Astrophysics Data System (ADS)

Mohammed, Osama A.; Jones, W. Kinzy

1988-11-01

This paper presents a new technique for the design of a miniature dc-dc converter used in energy producing implantable devices such as defibrillators and advanced pacemakers. This converter is inserted in such a device and is used to boost the voltage from a low voltage implanted battery to high voltage energy storage capacitors in a short period of time. The stored energy is then delivered, when needed, through an energy delivery circuit in order to stimulate or defibrillate the heart. The converter takes the form of a flyback topology which includes a miniature transformer and a specialized control circuit. The transformer was designed using a new numerical synthesis method which utilizes finite elements and dynamic programming for predicting the geometries of the transformer's magnetic circuit. The final transformer design satisfied the performance criteria and provided means for selecting the converter components. The obtained performance results for the transformer and the dc-dc converter were in excellent agreement with laboratory performance tests.

Transient analysis of an HTS DC power cable with an HVDC system

NASA Astrophysics Data System (ADS)

Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun; Yang, Byeongmo

2013-11-01

The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.

Sunny Side Up

ERIC Educational Resources Information Center

Murphy, Jim

1976-01-01

Energy conservation high on the client's priority list led to a solar collector roof for the new science building at the Madeira School, located in the Virginia suburbs of Washington, D.C. (Author/MLF)

Ion energy distributions in bipolar pulsed-dc discharges of methane measured at the biased cathode

NASA Astrophysics Data System (ADS)

Corbella, C.; Rubio-Roy, M.; Bertran, E.; Portal, S.; Pascual, E.; Polo, M. C.; Andújar, J. L.

2011-02-01

The ion fluxes and ion energy distributions (IED) corresponding to discharges in methane (CH4) were measured in time-averaged mode with a compact retarding field energy analyser (RFEA). The RFEA was placed on a biased electrode at room temperature, which was powered by either radiofrequency (13.56 MHz) or asymmetric bipolar pulsed-dc (250 kHz) signals. The shape of the resulting IED showed the relevant populations of ions bombarding the cathode at discharge parameters typical in the material processing technology: working pressures ranging from 1 to 10 Pa and cathode bias voltages between 100 and 200 V. High-energy peaks in the IED were detected at low pressures, whereas low-energy populations became progressively dominant at higher pressures. This effect is attributed to the transition from collisionless to collisional regimes of the cathode sheath as the pressure increases. On the other hand, pulsed-dc plasmas showed broader IED than RF discharges. This fact is connected to the different working frequencies and the intense peak voltages (up to 450 V) driven by the pulsed power supply. This work improves our understanding in plasma processes at the cathode level, which are of crucial importance for the growth and processing of materials requiring controlled ion bombardment. Examples of industrial applications with these requirements are plasma cleaning, ion etching processes during fabrication of microelectronic devices and plasma-enhanced chemical vapour deposition of hard coatings (diamond-like carbon, carbides and nitrides).

Chronic alcohol consumption is associated with changes in the distribution, immunophenotype, and the inflammatory cytokine secretion profile of circulating dendritic cells.

PubMed

Laso, Francisco Javier; Vaquero, José Miguel; Almeida, Julia; Marcos, Miguel; Orfao, Alberto

2007-05-01

Alcoholism is frequently associated with altered immune responses, limited information being available on its effects on dendritic cells (DC). In the present study we analyze the effects of chronic alcoholism on circulating DC. For the first time we studied the numerical distribution of DC in peripheral blood (PB), their immunophenotype, and their ex vivo pattern of spontaneous cytokine secretion, in chronic alcoholic patients without liver disease (AWLD group; n=17) and active ethanol (EtOH) intake, as well as in subjects with alcohol liver cirrhosis (ALC group; n=21). A significantly decreased HLADR expression and an increased reactivity for CD123 was observed on PB DC from AWLD patients; additionally, increased secretion of interleukin (IL) 1beta, IL6, IL12, and tumor necrosis factor-alpha (TNFalpha) by DC was also noted in this group. Conversely, patients with ALC and at least 1 year of alcohol withdrawal (ALCAW group) showed a decreased number of total circulating DC, whereas ALC patients with active EtOH intake (ALCET group) had an abnormally low production of IL1beta and TNFalpha by PB DC. Chronic alcoholism in the absence of liver disease is associated with an increased secretion of inflammatory cytokines by PB DC, whereas ALCAW and ALCET patients show decreased numbers of circulating DC and reduced secretion of these cytokines, respectively.

Design and modelling of high gain DC-DC converters for fuel cell hybrid electric vehicles

NASA Astrophysics Data System (ADS)

Elangovan, D.; Karthigeyan, V.; Subhanu, B.; Ashwin, M.; Arunkumar, G.

2017-11-01

Transportation (Diesel and petrol internal combustion engine vehicles) approximately contributes to 25.5% of total CO2 emission. Thus diesel and petrol engine vehicles are the most dominant contributors of CO2 emission which leads global warming which causes climate change. The problem of CO2 emission and global warming can be reduced by focusing on renewable energy vehicles. Out of the available renewable energy sources fuel cell is the only source which has reasonable efficiency and can be used in vehicles. But the main disadvantage of fuel cell is its slow response time. So energy storage systems like batteries and super capacitors are used in parallel with the fuel cell. Fuel cell is used during steady state vehicle operation while during transient conditions like starting, acceleration and braking batteries and super capacitors can supply or absorb energy. In this paper a unidirectional fuel cell DC-DC converter and bidirectional energy storage system DC-DC converter is proposed, which can interface dc sources at different voltage levels to the dc bus and also it can independently control the power flow from each energy source to the dc bus and vice versa. The proposed converters are designed and simulated using PSIM version 9.1.1 and gate pulse pattern, input and output voltage waveforms of the converters for steady state operation are studied.

High temperature superconductor dc SQUID micro-susceptometer for room temperature objects

NASA Astrophysics Data System (ADS)

Faley, M. I.; Pratt, K.; Reineman, R.; Schurig, D.; Gott, S.; Atwood, C. G.; Sarwinski, R. E.; Paulson, D. N.; Starr, T. N.; Fagaly, R. L.

2004-05-01

We have developed a scanning magnetic microscope (SMM) with 25 µm resolution in spatial position for the magnetic features of room temperature objects. The microscope consists of a high-temperature superconductor (HTS) dc SQUID sensor, suspended in vacuum with a self-adjusting standoff, close spaced liquid nitrogen Dewar, X-Y scanning stage and a computer control system. The HTS SQUIDs were optimized for better spatial and field resolutions for operation at liquid nitrogen temperature. Measured inside a magnetic shield, the 10 pT Hz-1/2 typical noise of the SQUIDs is white down to frequencies of about 10 Hz, increasing up to about 20 pT Hz-1/2 at 1 Hz. The microscope is mounted on actively damped platforms, which negate vibrations from the environment as well as damping internal stepper motor noises. A high-resolution video telescope and a 1 µm precision z-axis positioning system allow a close positioning of the sample under the sensor. The ability of the sensors to operate in unshielded environmental conditions with magnetic fields up to about 15 G allowed us to perform 2D mapping of the local ac and dc susceptibility of the objects.

A polarized atomic-beam target for COSY-Jülich

NASA Astrophysics Data System (ADS)

Eversheim, P. D.; Altmeier, M.; Felden, O.; Glende, M.; Walker, M.; Hiemer, A.; Gebel, R.

1998-01-01

An atomic-beam target (ABT) for the EDDA experiment has been built in Bonn and was tested for the very first time at the cooler synchrotron COSY. The ABT differs from the polarized colliding-beams ion source for COSY in the DC-operation of the dissociator and the use of permanent 6-pole magnets. At present the beam optics of the ABT is set-up for maximum density in the interaction zone, but for target-cell operation it can be modified to give maximum intensity. The modular concept of this atomic ground-state target allows to provide all vector- (and tensor) polarizations for protons and deuterons, respectively. Up to now the polarization of the atomic-beam could be verified by the EDDA experiment to be ≳80% with a density in the interaction zone of ≳1011atoms/cm2.

47 CFR 73.561 - Operating schedule; time sharing.

Code of Federal Regulations, 2013 CFR

2013-10-01

... in triplicate by each licensee with the Commission, Attention: Audio Division, Media Bureau, prior to... the Commission in Washington, DC, Attention: Audio Division, Media Bureau. (d) In the event that... provided that notification is sent to the Commission in Washington, DC, Attention: Audio Division, Media...

Characteristic variations of sea surface temperature with multiple time scales in the North Pacific

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanimoto, Youichi; Hanawa, Kimio; Toba, Yoshiaki

1993-06-01

It is unclear whether the recent increases in global temperatures are really due to the increase of greenhouse gases or are a manifestation of natural variability. Temporal evolution and spectral structure of sea surface temperature (SST) anomalies in the North Pacific over the last 37 years are investigated on the three characteristic time scales: shorter than 24 months (HF), 24-60 months (ES), and longer than 60 months (DC). The leading empirical-orthogonal function (EOF) for the DC time scale is characterized by a zonally elongated monopole centered at around 40[degrees]N, 180[degrees]. The leading EOF for the HF time scale is somewhatmore » similar to that for the DC time scale, although there are two centers of action with the same polarity at the mid and western Pacific. The leading EOF for the ES time scale, however, exhibits a different pattern whose center of action at the mid Pacific is located farther southeastward. In the time evolution of the SST anomalies associated with the leading EOF of the DC time scale, several anomaly periods can be identified that last five years or longer. The transition from a persistent period to another with the opposite polarity is generally very brief, except for the one that lasts throughout the late 1960s. The EOF analysis was repeated separately on these persistent anomaly periods and the long transition period. The spatial structure of the leading EOF of the SST variability with the ES time scale is found to be sensitive to the polarity of the decadal anomaly. These results are suggestive of the possible influence of the decadal SST variability upon the spatial structure of the variability with shorter time scales. 31 refs., 8 figs.« less

Two-stage energy storage equalization system for lithium-ion battery pack

NASA Astrophysics Data System (ADS)

Chen, W.; Yang, Z. X.; Dong, G. Q.; Li, Y. B.; He, Q. Y.

2017-11-01

How to raise the efficiency of energy storage and maximize storage capacity is a core problem in current energy storage management. For that, two-stage energy storage equalization system which contains two-stage equalization topology and control strategy based on a symmetric multi-winding transformer and DC-DC (direct current-direct current) converter is proposed with bidirectional active equalization theory, in order to realize the objectives of consistent lithium-ion battery packs voltages and cells voltages inside packs by using a method of the Range. Modeling analysis demonstrates that the voltage dispersion of lithium-ion battery packs and cells inside packs can be kept within 2 percent during charging and discharging. Equalization time was 0.5 ms, which shortened equalization time of 33.3 percent compared with DC-DC converter. Therefore, the proposed two-stage lithium-ion battery equalization system can achieve maximum storage capacity between lithium-ion battery packs and cells inside packs, meanwhile efficiency of energy storage is significantly improved.

The influence of NH3 on NO2 conversion in a dc corona discharge in N2:O2:CO2:NO2:NH3 mixture

NASA Astrophysics Data System (ADS)

Dors, Mirosław; Mizeraczyk, Jerzy; Czech, Tadeusz; Konieczka, Jerzy

1996-10-01

The aim of this paper is to investigate the influence of NH3 additive (540-1470 ppm) on the conversion of NO2 and the creation of NO and N2O in a mixture of N2:O2:CO2: NO2:NH3 subjected to the so-called direct current (dc) corona discharge. The dc corona discharge was generated in a needle-to-plate reactor. Seven positively polarized needles were used as one electrode and a stainless steel plate as the other. The time-averaged discharge current was varied from 0 to 7 mA. It was found that the dc corona discharge decomposed NO2 and produced NO and N2O. The reduction of NO2 was higher without NH3 additive if the residence time of the operating gas was relatively short. However, in a longer corona discharge processing the NH3 additive may be useful for reduction of NO2.

Power-MOSFET Voltage Regulator

NASA Technical Reports Server (NTRS)

Miller, W. N.; Gray, O. E.

1982-01-01

Ninety-six parallel MOSFET devices with two-stage feedback circuit form a high-current dc voltage regulator that also acts as fully-on solid-state switch when fuel-cell out-put falls below regulated voltage. Ripple voltage is less than 20 mV, transient recovery time is less than 50 ms. Parallel MOSFET's act as high-current dc regulator and switch. Regulator can be used wherever large direct currents must be controlled. Can be applied to inverters, industrial furnaces photovoltaic solar generators, dc motors, and electric autos.

Dual- vs. single-chamber defibrillators for primary prevention of sudden cardiac death: long-term follow-up of the Défibrillateur Automatique Implantable-Prévention Primaire registry.

PubMed

Defaye, Pascal; Boveda, Serge; Klug, Didier; Beganton, Frankie; Piot, Olivier; Narayanan, Kumar; Périer, Marie-Cécile; Gras, Daniel; Fauchier, Laurent; Bordachar, Pierre; Algalarrondo, Vincent; Babuty, Dominique; Deharo, Jean-Claude; Leclercq, Christophe; Marijon, Eloi; Sadoul, Nicolas

2017-09-01

Implantable cardioverter defibrillators (ICDs) are an effective primary prevention of sudden cardiac death. We examined whether dual-chamber (DC) ICDs confer a greater benefit than single-chamber (SC) ICDs, and compared the long-term outcomes of recipients of each type of device implanted for primary prevention. Between 2002 and 2012, the DAI-PP registry consecutively enrolled 1258 SC- and 1280 DC-ICD recipients at 12 French medical centres. The devices were interrogated at 4- to 6-month intervals during outpatient visits, with a focus on the therapies delivered. The study endpoints were incidence of appropriate therapies, ICD-related morbidity, and deaths from all and from specific causes. The mean age of the SC- and DC-ICD recipients was 59 ± 12 and 62 ± 11 years, respectively (P< 0.0001). The distribution of genders, New York Heart Association functional classes and glomerular filtration rates, and the rates of ischaemic vs. dilated cardiomyopathies and of defibrillation tests at implant, were similar in both study groups. The rates of periprocedural complications were 12.1% in the DC- vs. 8.8% in the SC-ICD groups (P= 0.008). Over a mean follow-up of 3.1 ± 2.2 years, pulse generators were replaced in 21.9% of the DC- vs. 13.6% of the SC-ICD group (P< 0.0001). The proportions of patients treated with ≥1 appropriate therapies (24.7 vs. 23.8%) and ≥1 inappropriate shocks (8.4 vs. 7.8%), and all-cause mortality (12.4 vs. 13.2%) were similar in both groups. In this large registry of ICD implanted for primary prevention, DC-ICDs were associated with higher rates of peri-implant complications and generator replacements, whereas the survival and rates of inappropriate shocks were similar in both groups. NCT#01992458. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.

Synergistic suppression of autoimmune arthritis through concurrent treatment with tolerogenic DC and MSC

PubMed Central

Li, Rong; Zhang, Yujuan; Zheng, Xiufen; Peng, Shanshan; Yuan, Keng; Zhang, Xusheng; Min, Weiping

2017-01-01

Rheumatoid arthritis (RA) is an autoimmune disease characterized by progressive immune-mediated joint deterioration. Current treatments are not antigen specific and are associated with various adverse. We have previously demonstrated that tolerogenic dendritic cells (Tol-DC) are potent antigen-specific immune regulators, which hold great promise in immunotherapy of autoimmune diseases. In this study, we aimed to develop new immunotherapy by combining Tol-DC and mesenchymal stem cells (MSC). We demonstrated that RelB gene silencing resulted in generation of Tol-DC that suppressed T cell responses and selectively promoted Treg generation. The combination of MSC synergized the tolerogenic capacity of Tol-DC in inhibition of T cell responses. In murine collagen-induced arthritis (CIA) model, we demonstrated that progression of arthritis was inhibited with administration of RelB gene-silenced Tol-DC or MSC. This therapeutic effect was remarkably enhanced with concurrent treatment of combination Tol-DC and MSC as demonstrated by improved clinical symptoms, decreased clinical scores and attenuated joint damage. These therapeutic effects were associated with suppression of CII-specific T cell responses, polarization of Th and inhibition of proinflammatory cytokines, and reduced cartilage degeneration. This study for the first time demonstrates a new approach to treat autoimmune inflammatory joint disease with concurrent treatment of RelB gene-silenced Tol-DC and MSC. PMID:28230210

Reliability of hybrid photovoltaic DC micro-grid systems for emergency shelters and other applications

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.; Schleith, Susan

2014-10-01

Improvement of energy efficiency in the SunSmart Schools Emergency Shelters requires new methods for optimizing the energy consumption within the shelters. One major limitation in current systems is the requirement of converting direct current (DC) power generated from the PV array into alternating current (AC) power which is distributed throughout the shelters. Oftentimes, this AC power is then converted back to DC to run certain appliances throughout the shelters resulting in a significant waste of energy due to DC to AC and then again AC to DC conversion. This paper seeks to extract the maximum value out of PV systems by directly powering essential load components within the shelters that already run on DC power without the use of an inverter and above all to make the system reliable and durable. Furthermore, additional DC applications such as LED lighting, televisions, computers and fans operated with DC brushless motors will be installed as replacements to traditional devices in order to improve efficiency and reduce energy consumption. Cost of energy storage technologies continue to decline as new technologies scale up and new incentives are put in place. This will provide a cost effective way to stabilize the energy generation of a PV system as well as to provide continuous energy during night hours. It is planned to develop a pilot program of an integrated system that can provide uninterrupted DC power to essential base load appliances (heating, cooling, lighting, etc.) at the Florida Solar Energy Center (FSEC) command center for disaster management. PV arrays are proposed to be installed on energy efficient test houses at FSEC as well as at private homes having PV arrays where the owners volunteer to participate in the program. It is also planned to monitor the performance of the PV arrays and functioning of the appliances with the aim to improve their reliability and durability. After a successful demonstration of the hybrid DC microgrid based emergency shelter together with the monitoring system, it is planned to replicate it at other schools in Florida and elsewhere to provide continuous power for essential applications, maximizing the value of PV generation systems.

Single-Stage Step up/down Driver for Permanent-Magnet Synchronous Machines

NASA Astrophysics Data System (ADS)

Chen, T. R.; Juan, Y. L.; Huang, C. Y.; Kuo, C. T.

2017-11-01

The two-stage circuit composed of a step up/down dc converter and a three-phase voltage source inverter is usually adopted as the electric vehicle’s motor driver. The conventional topology is more complicated. Additional power loss resulted from twice power conversion would also cause lower efficiency. A single-stage step up/down Permanent-Magnet Synchronous Motor driver for Brushless DC (BLDC) Motor is proposed in this study. The number components and circuit complexity are reduced. The low frequency six-step square-wave control is used to reduce the switching losses. In the proposed topology, only one active switch is gated with a high frequency PWM signal for adjusting the rotation speed. The rotor position signals are fed back to calculate the motor speed for digital close-loop control in a MCU. A 600W prototype circuit is constructed to drive a BLDC motor with rated speed 3000 rpm, and can control the speed of six sections.

The hairline plasma: An intermittent negative dc-corona discharge at atmospheric pressure for plasma medical applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bussiahn, R.; Brandenburg, R.; Gerling, T.

2010-04-05

A cold atmospheric pressure plasma source, called hairline plasma, for biological and medical applications has been developed. Using the physical effect of the negative dc corona discharge, a nanosecond pulsed microplasma has been created. The device produces a very thin (dapprox30 mum) plasma filament with a length of up to 1.5 cm. Due to this geometrical parameters this plasma is particularly suitable for the treatment of microscopic cavities. The low plasma temperature allows to treat the human skin without any heating or painful irritation.

Characterization of PZT Capacitor Structures with Various Electrode Materials Processed In-Situ Using AN Automated, Rotating Elemental Target, Ion Beam Deposition System

NASA Astrophysics Data System (ADS)

Gifford, Kenneth Douglas

Ferroelectric thin film capacitor structures containing lead zirconate titanate (PZT) as the dielectric, with the chemical formula Pb(rm Zr_{x }Ti_{1-x})O_3, were synthesized in-situ with an automated ion beam sputter deposition system. Platinum (Pt), conductive ruthenium oxide (RuO_2), and two types of Pt-RuO_2 hybrid electrodes were used as the electrode materials. The capacitor structures are characterized in terms of microstructure and electrical characteristics. Reduction or elimination of non-ferroelectric phases, that nucleate during PZT processing on Pt/TiO _2/MgO and RuO_2/MgO substrates, is achieved by reducing the thickness of the individually deposited layers and by interposing a buffer layer (~100-200A) of PbTiO _3 (PT) between the bottom electrode and the PZT film. Capacitor structures containing a Pt electrode exhibit poor fatigue resistance, irregardless of the PZT microstructure or the use of a PT buffer layer. From these results, and results from similar capacitors synthesized with sol-gel and laser ablation, PZT-based capacitor structures containing Pt electrodes are considered to be unsuitable for use in memory devices. Using a PT buffer layer, in capacitor structures containing RuO_2 top and bottom electrodes and polycrystalline, highly (101) oriented PZT, reduces or eliminates the nucleation of zirconium-titanium oxide, non-ferroelectric species at the bottom electrode interface during processing. This results in good fatigue resistance up to ~2times10^ {10} switching cycles. DC leakage current density vs. time measurements follow the Curie-von Schweidler law, J(t) ~ t^ {rm -n}. Identification of the high electric field current conduction mechanism is inconclusive. The good fatigue resistance, low dc leakage current, and excellent retention, qualifies the use of these capacitor structures in non-volatile random access (NVRAM) and dynamic random access (DRAM) memory devices. Excellent fatigue resistance (10% loss in remanent polarization up to ~2times10^ {10} switching cycles), low dc leakage current, and excellent retention are observed in capacitor structures containing polycrystalline PZT (exhibiting dominant (001) and (100) XRD reflections), a Pt-RuO_2 hybrid bottom electrode (Type IA), and an RuO _2 top electrode. These results, and electrical characterization results on capacitors containing co-deposited Pt-RuO_2 hybrid electrodes (Type II), show potential for application of these capacitor structures in NVRAM and DRAM memory devices.

Upgrading a high-throughput spectrometer for high-frequency (<400 kHz) measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishizawa, T., E-mail: nishizawa@wisc.edu; Nornberg, M. D.; Den Hartog, D. J.

2016-11-15

The upgraded spectrometer used for charge exchange recombination spectroscopy on the Madison Symmetric Torus resolves emission fluctuations up to 400 kHz. The transimpedance amplifier’s cutoff frequency was increased based upon simulations comparing the change in the measured photon counts for time-dynamic signals. We modeled each signal-processing stage of the diagnostic and scanned the filtering frequency to quantify the uncertainty in the photon counting rate. This modeling showed that uncertainties can be calculated based on assuming each amplification stage is a Poisson process and by calibrating the photon counting rate with a DC light source to address additional variation.

Upgrading a high-throughput spectrometer for high-frequency (<400 kHz) measurements

NASA Astrophysics Data System (ADS)

Nishizawa, T.; Nornberg, M. D.; Den Hartog, D. J.; Craig, D.

2016-11-01

The upgraded spectrometer used for charge exchange recombination spectroscopy on the Madison Symmetric Torus resolves emission fluctuations up to 400 kHz. The transimpedance amplifier's cutoff frequency was increased based upon simulations comparing the change in the measured photon counts for time-dynamic signals. We modeled each signal-processing stage of the diagnostic and scanned the filtering frequency to quantify the uncertainty in the photon counting rate. This modeling showed that uncertainties can be calculated based on assuming each amplification stage is a Poisson process and by calibrating the photon counting rate with a DC light source to address additional variation.

Eddy current imaging with an atomic radio-frequency magnetometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wickenbrock, Arne, E-mail: wickenbr@uni-mainz.de; Leefer, Nathan; Blanchard, John W.

2016-05-02

We use a radio-frequency {sup 85}Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.

Walsh Preprocessor.

DTIC Science & Technology

1980-08-01

tile se(q uenw threshold does not utilize thle D)C level inlforiat ion and the time thlresliolditig adaptively adjusts for DC lvel . 𔃻This characteristic...lowest 256/8 = 32 elements. The above observation can be mathematically proven to also relate the fact that the lowest (NT/W) elements can, at worst case

A malaria protein factor induces IL-4 production by dendritic cells via PI3K-Akt-NF-κB signaling independent of MyD88/TRIF and promotes Th2 response.

PubMed

Wu, Xianzhu; Gowda, Nagaraj M; Kawasawa, Yuka I; Gowda, D Channe

2018-04-17

Dendritic cells (DC) and cytokines produced by DC play crucial roles in inducing and regulating pro-/anti-inflammatory and Th1/Th2 responses. DC are known to produce Th1-promoting cytokine, IL-12, in response to malaria and other pathogenic infections, but it is thought that DC do not produce Th2-promoting cytokine, IL-4. Here, we show that a protein factor of malaria parasites induces IL-4 responses by CD11c hi MHCII hi CD3ε - CD49b - CD19 - FcεRI - DC via PI3K-Akt-NF-κB signaling independent of TLR-MyD88/TRIF. Malaria parasite-activated DC induced IL-4 responses by T cells both in vitro and in vivo , favoring Th2, and il-4 deficient DC were unable to induce IL-4 expression by T cell.  Interestingly, lethal parasites, Plasmodium falciparum and P. berghei ANKA, induced IL-4 response primarily by CD8a - DC, whereas nonlethal P. yoelii induced IL-4 by both CD8α + and CD8α - DC. In both P. berghei ANKA- and P. yoelii -infected mice, IL-4-expressing CD8α - DC did not express IL-12, but a distinct CD8α - DC subset expressed IL-12. In P. berghei ANKA infection, CD8α + DC expressed IL-12 but not IL-4, whereas in P. yoelii infection CD8α + DC expressed IL-4 but not IL-12. This differential IL-4 and IL-12 responses by DC subsets may contribute to different Th1/Th2 development and clinical outcomes in lethal and nonlethal malaria. Our results for the first time demonstrate that a malaria protein factor induces IL-4 production by DC via PI3K-Akt-NF-κB signaling, revealing signaling and molecular mechanisms that initiate and promote Th2 development. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

7 CFR 1230.629 - Registration and voting procedures for importers.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF.... Brown, P.O. Box 44366, Washington, DC 20026-4366. Importers may pick up the voting materials in-person...

7 CFR 1230.629 - Registration and voting procedures for importers.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF.... Brown, P.O. Box 44366, Washington, DC 20026-4366. Importers may pick up the voting materials in-person...

Numerical Evaluation of the "Dual-Kernel Counter-flow" Matric Convolution Integral that Arises in Discrete/Continuous (D/C) Control Theory

NASA Technical Reports Server (NTRS)

Nixon, Douglas D.

2009-01-01

Discrete/Continuous (D/C) control theory is a new generalized theory of discrete-time control that expands the concept of conventional (exact) discrete-time control to create a framework for design and implementation of discretetime control systems that include a continuous-time command function generator so that actuator commands need not be constant between control decisions, but can be more generally defined and implemented as functions that vary with time across sample period. Because the plant/control system construct contains two linear subsystems arranged in tandem, a novel dual-kernel counter-flow convolution integral appears in the formulation. As part of the D/C system design and implementation process, numerical evaluation of that integral over the sample period is required. Three fundamentally different evaluation methods and associated algorithms are derived for the constant-coefficient case. Numerical results are matched against three available examples that have closed-form solutions.

Preparation of Power Distribution System for High Penetration of Renewable Energy Part I. Dynamic Voltage Restorer for Voltage Regulation Pat II. Distribution Circuit Modeling and Validation

NASA Astrophysics Data System (ADS)

Khoshkbar Sadigh, Arash

Part I: Dynamic Voltage Restorer In the present power grids, voltage sags are recognized as a serious threat and a frequently occurring power-quality problem and have costly consequence such as sensitive loads tripping and production loss. Consequently, the demand for high power quality and voltage stability becomes a pressing issue. Dynamic voltage restorer (DVR), as a custom power device, is more effective and direct solutions for "restoring" the quality of voltage at its load-side terminals when the quality of voltage at its source-side terminals is disturbed. In the first part of this thesis, a DVR configuration with no need of bulky dc link capacitor or energy storage is proposed. This fact causes to reduce the size of the DVR and increase the reliability of the circuit. In addition, the proposed DVR topology is based on high-frequency isolation transformer resulting in the size reduction of transformer. The proposed DVR circuit, which is suitable for both low- and medium-voltage applications, is based on dc-ac converters connected in series to split the main dc link between the inputs of dc-ac converters. This feature makes it possible to use modular dc-ac converters and utilize low-voltage components in these converters whenever it is required to use DVR in medium-voltage application. The proposed configuration is tested under different conditions of load power factor and grid voltage harmonic. It has been shown that proposed DVR can compensate the voltage sag effectively and protect the sensitive loads. Following the proposition of the DVR topology, a fundamental voltage amplitude detection method which is applicable in both single/three-phase systems for DVR applications is proposed. The advantages of proposed method include application in distorted power grid with no need of any low-pass filter, precise and reliable detection, simple computation and implementation without using a phased locked loop and lookup table. The proposed method has been verified by simulation and experimental tests under various conditions considering all possible cases such as different amounts of voltage sag depth (VSD), different amounts of point-on-wave (POW) at which voltage sag occurs, harmonic distortion, line frequency variation, and phase jump (PJ). Furthermore, the ripple amount of fundamental voltage amplitude calculated by the proposed method and its error is analyzed considering the line frequency variation together with harmonic distortion. The best and worst detection time of proposed method were measured 1ms and 8.8ms, respectively. Finally, the proposed method has been compared with other voltage sag detection methods available in literature. Part 2: Power System Modeling for Renewable Energy Integration: As power distribution systems are evolving into more complex networks, electrical engineers have to rely on software tools to perform circuit analysis. There are dozens of powerful software tools available in the market to perform the power system studies. Although their main functions are similar, there are differences in features and formatting structures to suit specific applications. This creates challenges for transferring power system circuit models data (PSCMD) between different software and rebuilding the same circuit in the second software environment. The objective of this part of thesis is to develop a Unified Platform (UP) to facilitate transferring PSCMD among different software packages and relieve the challenges of the circuit model conversion process. UP uses a commonly available spreadsheet file with a defined format, for any home software to write data to and for any destination software to read data from, via a script-based application called PSCMD transfer application. The main considerations in developing the UP are to minimize manual intervention and import a one-line diagram into the destination software or export it from the source software, with all details to allow load flow, short circuit and other analyses. In this study, ETAP, OpenDSS, and GridLab-D are considered, and PSCMD transfer applications written in MATLAB have been developed for each of these to read the circuit model data provided in the UP spreadsheet. In order to test the developed PSCMD transfer applications, circuit model data of a test circuit and a power distribution circuit from Southern California Edison (SCE) - a utility company - both built in CYME, were exported into the spreadsheet file according to the UP format. Thereafter, circuit model data were imported successfully from the spreadsheet files into above mentioned software using the PSCMD transfer applications developed for each software. After the SCE studied circuit is transferred into OpenDSS software using the proposed UP scheme and developed application, it has been studied to investigate the impacts of large-scale solar energy penetration. The main challenge of solar energy integration into power grid is its intermittency (i.e., discontinuity of output power) nature due to cloud shading of photovoltaic panels which depends on weather conditions. In order to conduct this study, OpenDSS time-series simulation feature, which is required due to intermittency of solar energy, is utilized. In this study, the impacts of intermittency of solar energy penetration, especially high-variability points, on voltage fluctuation and operation of capacitor bank and voltage regulator is provided. In addition, the necessity to interpolate and resample unequally spaced time-series measurement data and convert them to equally spaced time-series data as well as the effect of resampling time-interval on the amount of error is discussed. Two applications are developed in Matlab to do interpolation and resampling as well as to calculate the amount of error for different resampling time-intervals to figure out the suitable resampling time-interval. Furthermore, an approach based on cumulative distribution, regarding the length for lines/cables types and the power rating for loads, is presented to prioritize which loads, lines and cables the meters should be installed at to have the most effect on model validation.

Glutaric aciduria type I: outcome of patients with early- versus late-diagnosis.

PubMed

Couce, Ma Luz; López-Suárez, Olalla; Bóveda, Ma Dolores; Castiñeiras, Daisy E; Cocho, José A; García-Villoria, Judith; Castro-Gago, Manuel; Fraga, José Ma; Ribes, Antonia

2013-07-01

Patients with Glutaric aciduria type 1 (GA-1) can be identified by newborn screening using tandem mass spectrometry. The clinical evolution of screened patients seems to be more favourable compared with those diagnosed later, although long-term evolution is still doubtful. We have evaluated the outcome in nine GA-1 patients diagnosed in our region during 12 years. Six were detected by newborn screening and 3 clinically. The birth prevalence was 1:35,027. High blood C5DC concentration, in 8/9 patients, was found, whereas all patients exhibited high concentration of this metabolite in urine. Therefore, urine C5DC was a good marker for the detection of this disease. Eight different mutations in the GCDH gene were identified, four of them were novel (p.R88H, p.Y398C, p.R372K, p.D220N); being p.R227P the mostcommon. Macrocephaly with enlarged frontotemporal subarachnoid space was present in 4/6 patients diagnosed by newborn screening, all these patients required high energy intake, and in two cases, enteral feeding during the first year of life was needed. One child had an intercurrent episode of feeding refuse with hypoglycemia at two years of age. The mean follow-up time of screened patients was 56 months, and patients still remain asymptomatic. However, after a mean follow-up of 97 months treatment efficacy was poor in unscreened patients, two of them showing a severe spastic tetraparesis. Plasma levels of lysine, tryptophan and carnitine, were the most useful biomarkers for the follow-up. Our data support that, early diagnosis and treatment strategies are essential measures for the good clinical evolution of GA-1 patients. Copyright © 2013 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Critical Role of Plasmacytoid Dendritic Cells in Regulating Gene Expression and Innate Immune Responses to Human Rhinovirus-16

PubMed Central

Xi, Yang; Troy, Niamh M.; Anderson, Denise; Pena, Olga M.; Lynch, Jason P.; Phipps, Simon; Bosco, Anthony; Upham, John W.

2017-01-01

Though human rhinoviruses (HRVs) are usually innocuous viruses, they can trigger serious consequences in certain individuals, especially in the setting of impaired interferon (IFN) synthesis. Plasmacytoid dendritic cells (pDCs) are key IFN producing cells, though we know little about the role of pDC in HRV-induced immune responses. Herein, we used gene expression microarrays to examine HRV-activated peripheral blood mononuclear cells (PBMCs) from healthy people, in combination with pDC depletion, to assess whether observed gene expression patterns were pDC dependent. As expected, pDC depletion led to a major reduction in IFN-α release. This was associated with profound differences in gene expression between intact PBMC and pDC-depleted PBMC, and major changes in upstream regulators: 70–80% of the HRV activated genes appeared to be pDC dependent. Real-time PCR confirmed key changes in gene expression, in which the following selected genes were shown to be highly pDC dependent: the transcription factor IRF7, both IL-27 chains (IL-27p28 and EBI3), the alpha chain of the IL-15 receptor (IL-15RA) and the IFN-related gene IFI27. HRV-induced IL-6, IFN-γ, and IL-27 protein synthesis were also highly pDC dependent. Supplementing pDC-depleted cultures with recombinant IL-15, IFN-γ, IL-27, or IL-6 was able to restore the IFN-α response, thereby compensating for the absence of pDC. Though pDC comprise only a minority population of migratory leukocytes, our findings highlight the profound extent to which these cells contribute to the immune response to HRV. PMID:29118754

Decoy receptor 3 alleviates hepatic fibrosis through suppressing inflammation activated by NF-κB signaling pathway.

PubMed

Jin, Zhenjing; Liu, Siqi; Zhang, Qian; Shao, Xue; Ma, Jingting; Pan, Liulan

2018-03-20

Hepatic fibrosis is a reversible pathological process. Inflammatory responses are the prevailing reactions during hepatic fibrosis. Decoy receptor 3 (DcR3) has been reported to have an anti-inflammatory effect. The aim of the study was to investigate the preventive effects of DcR3 on hepatic fibrosis. Hepatic fibrosis was induced in rats by administering intraperitoneally (ip.) 1% dimethylnitrosamine (DMN). DcR3 plasmid was delivered into rats by intravenous injection. After 4 weeks, the expression of DcR3, TNF-like molecule 1A (TL1A) and α-SMA of the liver tissue were checked. The levels of inflammatory cytokines such as TNF-α, IL-6 and IL-1β were detected using western blotting and quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Masson's trichrome staining for histopathological changes of the liver tissue was observed. Finally, the activity of NF-κB in the liver was examined by enzyme-linked immunosorbent assay (ELISA). A higher expression of DcR3 was observed in rats treated with DcR3 (p < 0.05). Histological results showed that DcR3 significantly attenuated pathology in hepatic fibrosis rats. Consistently, mRNA and protein levels of α-SMA, TL1A, TNF-α, IL-6, and IL-1β were repressed in the liver tissue after treatment with DcR3 (p < 0.05). Moreover, DcR3 also inhibited the activation of NF-κB in the liver tissue (p < 0.05). This study demonstrated that DcR3 attenuated liver injury and inflammatory responses in rats with hepatic fibrosis. We suggest DcR3 may be a prophylactic and promising therapeutic agent in the treatment of hepatic fibrosis.

Pulsed microdischarge with inductively coupled plasma mass spectrometry for elemental analysis on solid metal samples.

PubMed

Li, Weifeng; Yin, Zhibin; Cheng, Xiaoling; Hang, Wei; Li, Jianfeng; Huang, Benli

2015-05-05

Pulsed microdischarge employed as source for direct solid analysis was investigated in N2 environment at atmospheric pressure. Compared with direct current (DC) microdischarge, it exhibits advantages with respect to the ablation and emission of the sample. Comprehensive evidence, including voltage-current relationship, current density (j), and electron density (ne), suggests that pulsed microdischarge is in the arc regime while DC microdischarge belongs to glow. Capability in ablating metal samples demonstrates that pulsed microdischarge is a viable option for direct solid sampling because of the enhanced instantaneous energy. Using optical spectrometer, only common emission lines of N2 can be acquired in DC mode, whereas primary atomic and ionic lines of the sample are obtained in the case of pulsed mode. Calculations show a significant difference in N2 vibrational temperatures between DC and pulsed microdischarge. Combined with inductively coupled plasma mass spectrometry (ICPMS), pulsed microdischarge exhibits much better performances in calibration linearity and limits of detection (LOD) than those of DC discharge in direct analysis of samples of different matrices. To improve transmission efficiency, a mixture of Ar and N2 was employed as discharge gas as well as carrier gas in follow-up experiments, facilitating that LODs of most elements reached ng/g.

A fully integrated neural recording amplifier with DC input stabilization.

PubMed

Mohseni, Pedram; Najafi, Khalil

2004-05-01

This paper presents a low-power low-noise fully integrated bandpass operational amplifier for a variety of biomedical neural recording applications. A standard two-stage CMOS amplifier in a closed-loop resistive feedback configuration provides a stable ac gain of 39.3 dB at 1 kHz. A subthreshold PMOS input transistor is utilized to clamp the large and random dc open circuit potentials that normally exist at the electrode-electrolyte interface. The low cutoff frequency of the amplifier is programmable up to 50 Hz, while its high cutoff frequency is measured to be 9.1 kHz. The tolerable dc input range is measured to be at least +/- 0.25 V with a dc rejection factor of at least 29 dB. The amplifier occupies 0.107 mm2 in die area, and dissipates 115 microW from a 3 V power supply. The total measured input-referred noise voltage in the frequency range of 0.1-10 kHz is 7.8 microVrms. It is fabricated using AMI 1.5 microm double-poly double-metal n-well CMOS process. This paper presents full characterization of the dc, ac, and noise performance of this amplifier through in vitro measurements in saline using two different neural recording electrodes.

Induction of an oxalate decarboxylase in the filamentous fungus Trametes versicolor by addition of inorganic acids.

PubMed

Zhu, Cui Xia; Hong, Feng

2010-01-01

In order to improve yields and to reduce the cost of oxalate decarboxylase (OxDC, EC 4.1.1.2), the induction of OxDC in the white-rot fungus Trametes versicolor was studied in this work. OxDC was induced by addition of inorganic acids including hydrochloric acid, sulfuric acid, and phosphoric acid to culture media. The results showed that all the acids could enhance OxDC expression. The activity of the acid-induced OxDC rose continuously. All of the OxDC volumetric activities induced by the inorganic acids were higher than 20.0 U/L and were two times higher than that obtained with oxalic acid. OxDC productivity was around 4.0 U*L(-1)*day(-1). The highest specific activity against total protein was 3.2 U/mg protein at day 8 after induction of sulfuric acid, and the specific activity against mycelial dry weight was 10.6 U/g at day 9 after induction of hydrochloric acid. The growth of mycelia was inhibited slightly when the pH values in culture media was around 2.5-3.0, while the growth was inhibited heavily when the pH was lower than 2.5.

Alcohol exposure differentially effects anti-tumor immunity in females by altering dendritic cell function.

PubMed

Thompson, Matthew G; Navarro, Flor; Chitsike, Lennox; Ramirez, Luis; Kovacs, Elizabeth J; Watkins, Stephanie K

2016-12-01

Dendritic cells (DCs) are a critical component of anti-tumor immunity due to their ability to induce a robust immune response to antigen (Ag). Alcohol was previously shown to reduce DC ability to present foreign Ag and promote pro-inflammatory responses in situations of infection and trauma. However the impact of alcohol exposure on generation of an anti-tumor response, especially in the context of generation of an immune vaccine has not been examined. In the clinic, DC vaccines are typically generated from autologous blood, therefore prior exposure to substances such as alcohol may be a critical factor to consider regarding the effectiveness in generating an immune response. In this study, we demonstrate for the first time that ethanol differentially affects DC and tumor Ag-specific T cell responses depending on sex. Signaling pathways were found to be differentially regulated in DC in females compared to males and these differences were exacerbated by ethanol treatment. DC from female mice treated with ethanol were unable to activate Ag-specific cytotoxic T cells (CTL) as shown by reduced expression of CD44, CD69, and decreased production of granzyme B and IFNγ. Furthermore, although FOXO3, an immune suppressive mediator of DC function, was found to be upregulated in DC from female mice, ethanol related suppression was independent of FOXO3. These findings demonstrate for the first time differential impacts of alcohol on the immune system of females compared to males and may be a critical consideration for determining the effectiveness of an immune based therapy for cancer in patients that consume alcohol. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The effect of acute pre-exercise dark chocolate consumption on plasma antioxidant status, oxidative stress and immunoendocrine responses to prolonged exercise.

PubMed

Davison, Glen; Callister, Robin; Williamson, Gary; Cooper, Karen A; Gleeson, Michael

2012-02-01

Acute antioxidant supplementation may modulate oxidative stress and some immune perturbations that typically occur following prolonged exercise. The aims of the present study were to examine the effects of acutely consuming dark chocolate (high polyphenol content) on plasma antioxidant capacity, markers of oxidative stress and immunoendocrine responses to prolonged exercise. Fourteen healthy men cycled for 2.5 h at ~60% maximal oxygen uptake 2 h after consuming 100 g dark chocolate (DC), an isomacronutrient control bar (CC) or neither (BL) in a randomised-counterbalanced design. DC enhanced pre-exercise antioxidant status (P = 0.003) and reduced by trend (P = 0.088) 1 h post-exercise plasma free [F₂-isoprostane] compared with CC (also, [F₂-isoprostane] increased post-exercise in CC and BL but not DC trials). Plasma insulin concentration was significantly higher pre-exercise (P = 0.012) and 1 h post-exercise (P = 0.026) in the DC compared with the CC trial. There was a better maintenance of plasma glucose concentration on the DC trial (2-way ANOVA trial × time interaction P = 0.001), which decreased post-exercise in all trials but was significantly higher 1 h post-exercise (P = 0.039) in the DC trial. There were no between trial differences in the temporal responses (trial × time interactions all P > 0.05) of hypothalamic-pituitary-adrenal axis stress hormones, plasma interleukin-6, the magnitude of leukocytosis and neutrophilia and changes in neutrophil function. Acute DC consumption may affect insulin, glucose, antioxidant status and oxidative stress responses, but has minimal effects on immunoendocrine responses, to prolonged exercise.

Computational studies of suppression of microwave gas breakdown by crossed dc magnetic field using electron fluid model

NASA Astrophysics Data System (ADS)

Zhao, Pengcheng; Guo, Lixin; Shu, Panpan

2016-08-01

The gas breakdown induced by a square microwave pulse with a crossed dc magnetic field is investigated using the electron fluid model, in which the accurate electron energy distribution functions are adopted. Simulation results show that at low gas pressures the dc magnetic field of a few tenths of a tesla can prolong the breakdown formation time by reducing the mean electron energy. With the gas pressure increasing, the higher dc magnetic field is required to suppress the microwave breakdown. The electric field along the microwave propagation direction generated due to the motion of electrons obviously increases with the dc magnetic field, but it is much less than the incident electric field. The breakdown predictions of the electron fluid model agree very well with the particle-in-cell-Monte Carlo collision simulations as well as the scaling law for the microwave gas breakdown.

AASE-2 In-Situ Tracer Correlations of Methane Nitrous Oxide and Ozone as Observed Aboard the DC-8

NASA Technical Reports Server (NTRS)

Collins, J. E., Jr.; Sachse, G. W.; Anderson, B. E.; Weinheimer, A. J.; Walgea, J. G.; Ridley, B. A.

1993-01-01

We report in situ stratospheric measurements of CH4, N2O, and O3 obtained aboard the NASA DC-8 during the January-March 1992 Airborne Arctic Stratospheric Expedition II field campaign. These data demonstrate a strong linear correlation between N2O and CH4 in the lower stratosphere thus indicating that both species are effective tracers of stratospheric air motion. Measurements of both species on constant geometric height surfaces indicate that significant subsidence of the arctic stratospheric air mass occurred at DC-8 altitudes over the course of the AASE-II expedition. In addition, a widespread reduction in O3 mixing ratios (up to 20%) relative to these conserved tracers was also observed in the lower stratosphere in March a compared to January and February results.

AASE-2 in-situ tracer correlations of methane, nitrous oxide, and ozone as observed aboard the DC-8

NASA Technical Reports Server (NTRS)

Collins, J. E., Jr.; Sachse, G. W.; Anderson, B. E.; Weinheimer, A. J.; Walega, J. G.; Ridley, B. A.

1993-01-01

We report in situ stratospheric measurements of CH4, N2O, and O3 obtained aboard the NASA DC-8 during the January-March 1992 Airborne Arctic Stratospheric Expedition 2 field campaign. These data demonstrate a strong linear correlation between N2O and CH4 in the lower stratosphere thus indicating that both species are effective tracers of stratospheric air motion. Measurements of both species on constant geometric height surfaces indicate that significant subsidence of the arctic stratospheric air mass occurred at DC-8 altitudes over the course of the AASE-2 expedition. In addition, a widespread reduction in O3 mixing ratios (up to 20%) relative to these conserved tracers was also observed in the lower stratosphere in March as compared to January and February results.

Computerized implementation of higher-order electron-correlation methods and their linear-scaling divide-and-conquer extensions.

PubMed

Nakano, Masahiko; Yoshikawa, Takeshi; Hirata, So; Seino, Junji; Nakai, Hiromi

2017-11-05

We have implemented a linear-scaling divide-and-conquer (DC)-based higher-order coupled-cluster (CC) and Møller-Plesset perturbation theories (MPPT) as well as their combinations automatically by means of the tensor contraction engine, which is a computerized symbolic algebra system. The DC-based energy expressions of the standard CC and MPPT methods and the CC methods augmented with a perturbation correction were proposed for up to high excitation orders [e.g., CCSDTQ, MP4, and CCSD(2) TQ ]. The numerical assessment for hydrogen halide chains, polyene chains, and first coordination sphere (C1) model of photoactive yellow protein has revealed that the DC-based correlation methods provide reliable correlation energies with significantly less computational cost than that of the conventional implementations. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Dielectric and AC conductivity studies on SrBi4Ti4O15

NASA Astrophysics Data System (ADS)

Jose, Roshan; Saravanan, K. Venkata

2018-05-01

The four layered SrBi4Ti4O15 ceramics which belong to the aurivillius family of oxide was prepared by conventional solid state reaction technique. Analysis of the dielectric data as a function of temperature and frequency revealed normal phase transition. The frequency dependent ac conductivity follows Jonscher's universal power law. Frequency exponent (n), pre-exponential factor (A), bulk dc conductivity (σdc), and hopping frequency (ωp) were determined from the fitting curves. The variation of frequency exponent with temperature indicates that large polaron hopping mechanism up to curie-temperature, then its changes to small polaron hopping. The activation energies were calculated from ac conductivity, bulk dc conductivity and hopping frequency. The activation energies revealed that conductivity had contributions from migrations of oxygen vacancies, bismuth ion vacancies and strontium ion vacancies.

Pulsed-DC selfsputtering of copper

NASA Astrophysics Data System (ADS)

Wiatrowski, A.; Posadowski, W. M.; Radzimski, Z. J.

2008-03-01

At standard magnetron sputtering conditions (argon pressure ~0.5 Pa) inert gas particles are often entrapped in the formed films. Inert gas contamination can be eliminated by using the self-sustained magnetron sputtering process because it is done in the absence of the inert gas atmosphere. The self-sustained sputtering (SSS) gives also a unique condition during the transport of sputtered particles to the substrate. It is especially useful for filling high aspect ratio submicron scale structures for microelectronics. So far it has been shown that the self-sputtering process can be sustained in the DC operation mode (DC-SSS) only. The main disadvantage of DC-SSS process is instability related to possible arc formation. Usage of pulsed sputtering, similarly to reactive pulsed magnetron sputtering, could eliminate this problem. In this paper results of pulsed-DC self-sustained magnetron sputtering (pulsed DC-SSS) of copper are presented for the first time. The planar magnetron equipped with a 50 mm in diameter and 6 mm thick copper target was powered by DC-power supply modulated by power switch. The maximum target power was about 11 kW (~550W/cm2). The magnetron operation was investigated as a function of pulsing frequency (20-100 kHz) and duty factor (50-90%). The discharge extinction pressure was determined for these conditions. The plasma emission spectra (400-410nm range) and deposition rates were observed for both DC and pulsed DC sustained self-sputtering processes. The presented results illustrate that stable pulsed DC-SSS process can be obtained at pulsing frequency in the range of 60-100 kHz and duty factor of 70-90%.

The Isolation and Enrichment of Large Numbers of Highly Purified Mouse Spleen Dendritic Cell Populations and Their In Vitro Equivalents.

PubMed

Vremec, David

2016-01-01

Dendritic cells (DCs) form a complex network of cells that initiate and orchestrate immune responses against a vast array of pathogenic challenges. Developmentally and functionally distinct DC subtypes differentially regulate T-cell function. Importantly it is the ability of DC to capture and process antigen, whether from pathogens, vaccines, or self-components, and present it to naive T cells that is the key to their ability to initiate an immune response. Our typical isolation procedure for DC from murine spleen was designed to efficiently extract all DC subtypes, without bias and without alteration to their in vivo phenotype, and involves a short collagenase digestion of the tissue, followed by selection for cells of light density and finally negative selection for DC. The isolation procedure can accommodate DC numbers that have been artificially increased via administration of fms-like tyrosine kinase 3 ligand (Flt3L), either directly through a series of subcutaneous injections or by seeding with an Flt3L secreting murine melanoma. Flt3L may also be added to bone marrow cultures to produce large numbers of in vitro equivalents of the spleen DC subsets. Total DC, or their subsets, may be further purified using immunofluorescent labeling and flow cytometric cell sorting. Cell sorting may be completely bypassed by separating DC subsets using a combination of fluorescent antibody labeling and anti-fluorochrome magnetic beads. Our procedure enables efficient separation of the distinct DC subsets, even in cases where mouse numbers or flow cytometric cell sorting time is limiting.

Aberrant expression of decoy receptor 3 in human breast cancer: relevance to lymphangiogenesis.

PubMed

Wu, Qiuwan; Zheng, Yahong; Chen, Donghan; Li, Xiaohong; Lu, Chuanhui; Zhang, Zhiming

2014-05-15

Decoy receptor 3 (DcR3), a decoy receptor against Fas ligand belonging to the tumor necrosis factor receptor superfamily, is overexpressed in some forms of cancer. It was recently reported that DcR3 could protect endothelial cells from apoptosis, implying a potential role in the development of vessels, whereas its role in the lymphangiogenesis remains unclear. In the present study, we studied the DcR3 expression and its relationship with the lymphatic microvessel density (LMVD) to investigate if it played a role in the lymph metastasis of human breast cancer. Real-time polymerase chain reaction and immunohistochemistry were performed to measure the messenger RNA and protein expression of DcR3 in the breast cancer tissues, noncancerous counterparts, and axillary lymph node from 63 patients. LMVD in these specimens was assessed by counting the D2-40 labeled-microvessels. Furthermore, the correlations between DcR3 expression and LMVD and other clinicopathologic parameters were analyzed. DcR3 was overexpressed in the breast cancer tissue of 58 patients (92.1%) and was also expressed in vascular endothelial cells and tumor cells in the lymph nodes. LMVD in cancer tissue and lymph nodes were both positively correlated to the aberrant expression of DcR3. The relevance between DcR3 overexpression and LMVD revealed the existence of possible links between DcR3 and lymphangiogenesis. Based on these findings, it is important to further explore the regulation of lymphangiogenesis operated by the reverse tumor necrosis factor signaling of DcR3. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Third National Even Start Evaluation: Follow-Up Findings from the Experimental Design Study. NCEE 2005-3002

ERIC Educational Resources Information Center

Ricciuti, Anne E., St.Pierre, Robert G.; Lee, Wang; Parsad, Amanda

2004-01-01

Citation: Ricciuti, A.E., R.G. St.Pierre, W. Lee, A. Parsad & T. Rimdzius. Third National Even Start Evaluation: Follow-Up Findings From the Experimental Design Study. U.S. Department of Education, Institute of Education Sciences, National Center for Education Evaluation and Regional Assistance. Washington, D.C., 2004. Background: The Even…

"Catch-Up." Proceedings of the Annual Consumer Education "Catch-Up" Conference (2nd, Washington, D.C., November 11-12, 1976).

ERIC Educational Resources Information Center

Yates, Juanita, Ed.

This booklet summarizes a conference on consumer education which was held for educators, community leaders, program administrators, consumer advocates, and journalists to introduce the principal issues facing consumers and to explore effective program designs and teaching methods and materials. Following a brief executive summary of the conference…

2. Historic American Buildings Survey Photocopy courtesy of the Library ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Historic American Buildings Survey Photocopy courtesy of the Library of Congress VIEW NORTH UP SEVENTH STREET - Firemen's Insurance Company Building, 303 Seventh Street Northwest, Washington, District of Columbia, DC

Rejuvenation of the Innocent Bystander: Testing Spin-Up in Dwarf Carbon Stars

NASA Astrophysics Data System (ADS)

Green, Paul

2013-09-01

Carbon stars (C>O) were long assumed to all be giants, because only AGB stars dredge up significant carbon into their atmospheres. We now know that dwarf carbon (dC) stars are actually far more common than C giants. These dCs are hypothesized to have accreted C-rich envelope material from an AGB companion, in systems that have likely undergone a planetary nebula phase, eventually yielding a white dwarf and a dC that has gained both significant mass and angular momentum. To test whether the X-ray emission strength and spectral properties are consistent with a rejuvenated dynamo, we propose a Chandra pilot study of dCs selected from the SDSS; some have hot white dwarf companions (indicating more recent mass transfer), and all show Balmer emission lines (a sign of activity).

Ascophyllan Purified from Ascophyllum nodosum Induces Th1 and Tc1 Immune Responses by Promoting Dendritic Cell Maturation

PubMed Central

Zhang, Wei; Du, Jiang-Yuan; Jiang, Zedong; Okimura, Takasi; Oda, Tatsuya; Yu, Qing; Jin, Jun-O

2014-01-01

Marine-derived sulfated polysaccharides have been shown to possess certain anti-virus, anti-tumor, anti-inflammatory and anti-coagulant activities. However, the in vivo immunomodulatory effects of marine-derived pure compounds have been less well characterized. In this study, we investigated the effect of ascophyllan, a sulfated polysaccharide purified from Ascophyllum nodosum, on the maturation of mouse dendritic cells (DCs) in vitro and in vivo. Ascophyllan induced up-regulation of co-stimulatory molecules and production of pro-inflammatory cytokines in bone marrow-derived DCs (BMDCs). Moreover, in vivo administration of ascophyllan promotes up-regulation of CD40, CD80, CD86, MHC class I and MHC class II and production of IL-6, IL-12 and TNF-α in spleen cDCs. Interestingly, ascophyllan induced a higher degree of co-stimulatory molecule up-regulation and pro-inflammatory cytokine production than fucoidan, a marine-derived polysaccharide with well-defined effect for promoting DC maturation. Ascophyllan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in the presence of DCs in an IL-12-dependent manner. Finally, myeloid differentiation primary response 88 (MyD88) signaling pathway was essential for DC maturation induced by ascophyllan. Taken together, these results demonstrate that ascophyllan induces DC maturation, and consequently enhances Th1 and Tc1 responses in vivo. This knowledge could facilitate the development of novel therapeutic strategies to combat infectious diseases and cancer. PMID:25026264

DC graphite arc furnace, a simple system to reduce mixed waste volume

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wittle, J.K.; Hamilton, R.A.; Trescot, J.

1995-12-31

The volume of low-level radioactive waste can be reduced by the high temperature in a DC Graphite Arc Furnace. This volume reduction can take place with the additional benefit of having the solid residue being stabilized by the vitrified product produced in the process. A DC Graphite Arc Furnace is a simple system in which electricity is used to generate heat to vitrify the material and thermally decompose any organic matter in the waste stream. Examples of this type of waste are protective clothing, resins, and grit blast materials produced in the nuclear industry. The various Department of Energy (DOE)more » complexes produce similar low-level waste streams. Electro-Pyrolysis, Inc. and Svedala/Kennedy Van Saun are engineering and building small 50-kg batch and up to 3,000 kg/hr continuous feed DC furnaces for the remediation, pollution prevention, and decontamination and decommissioning segments of the treatment community. This process has been demonstrated under DOE sponsorship at several facilities and has been shown to produce stable waste forms from surrogate waste materials.« less

Microprocessor control of multiple peak power tracking DC/DC converters for use with solar cell arrays

NASA Technical Reports Server (NTRS)

Frederick, Martin E. (Inventor); Jermakian, Joel (Inventor)

1991-01-01

A method and an apparatus is provided for efficiently controlling the power output of a solar cell array string or a plurality of solar cell array strings to achieve a maximum amount of output power from the strings under varying conditions of use. Maximum power output from a solar array string is achieved through control of a pulse width modulated DC/DC buck converter which transfers power from a solar array to a load or battery bus. The input voltage from the solar array to the converter is controlled by a pulse width modulation duty cycle, which in turn is controlled by a differential signal controller. By periodically adjusting the control voltage up or down by a small amount and comparing the power on the load or bus with that generated at different voltage values a maximum power output voltage may be obtained. The system is totally modular and additional solar array strings may be added to the system simply by adding converter boards to the system and changing some constants in the controller's control routines.

[First report of Montagnea arenaria (D.C.) Zeller (Agaricales) in Chile].

PubMed

Madrid Lorca, Hugo; Muñoz, Mélica

2006-06-01

Montagnea arenaria (D.C.) Zeller (Agaricales), an interesting basidiomycete adapted to arid environments is recorded for the first time from a sample collected on sandy soil in the northern zone of Chile. Its mature fruiting body is described. Taxonomic and ecological comments are also addressed.

Application of Distributed DC/DC Electronics in Photovoltaic Systems

NASA Astrophysics Data System (ADS)

Kabala, Michael

In a typical residential, commercial or utility grade photovoltaic (PV) system, PV modules are connected in series and in parallel to form an array that is connected to a standard DC/AC inverter, which is then connected directly to the grid. This type of standard installation; however, does very little to maximize the energy output of the solar array if certain conditions exist. These conditions could include age, temperature, irradiance and other factors that can cause mismatch between PV modules in an array that severely cripple the output power of the system. Since PV modules are typically connected in series to form a string, the output of the entire string is limited by the efficiency of the weakest module. With PV module efficiencies already relatively low, it is critical to extract the maximum power out of each module in order to make solar energy an economically viable competitor to oil and gas. Module level DC/DC electronics with maximum power point (MPP) tracking solves this issue by decoupling each module from the string in order for the module to operate independently of the geometry and complexity of the surrounding system. This allows each PV module to work at its maximum power point by transferring the maximum power the module is able to deliver directly to the load by either boosting (stepping up) the voltage or bucking (stepping down) the voltage. The goal of this thesis is to discuss the development of a per-module DC/DC converter in order to maximize the energy output of a PV module and reduce the overall cost of the system by increasing the energy harvest.

Bimodal electric tissue ablation (BETA) - in-vivo evaluation of the effect of applying direct current before and during radiofrequency ablation of porcine liver.

PubMed

Cockburn, J F; Maddern, G J; Wemyss-Holden, S A

2007-03-01

To examine the effect of applying increasing amounts of direct current (DC) before and during alternating current radiofrequency ablation of porcine liver. Using a Radiotherapeutics RF3000 generator, a 9 V AC/DC transformer and a 16 G plain aluminium tube as an electrode, a control group of 24 porcine hepatic radiofrequency ablation zones was compared with 24 zones created using a bimodal electric tissue ablation (BETA) technique in three pigs. All ablations were terminated when tissue impedance rose to greater than 999 Omega or radiofrequency energy input fell below 5 W on three successive measurements taken at 1 min intervals. BETA ablations were performed in two phases: an initial phase of variable duration DC followed by a second phase during which standard radiofrequency ablation was applied simultaneously with DC. During this second phase, radiofrequency power input was regulated by the feedback circuitry of the RF3000 generator according to changes in tissue impedance. The diameters (mm) of each ablation zone were measured by two observers in two planes perpendicular to the plane of needle insertion. The mean short axis diameter of each ablation zone was subjected to statistical analysis. With increased duration of prior application of DC, there was a progressive increase in the diameter of the ablation zone (p<0.001). This effect increased sharply up to 300 s of pre-treatment after which a further increase in diameter occurred, but at a much lesser rate. A maximum ablation zone diameter of 32 mm was produced (control diameters 10-13 mm). Applying a 9 V DC to porcine liver in vivo, and continuing this DC application during subsequent radiofrequency ablation, results in larger ablation zone diameters compared with radiofrequency ablation alone.

A triple hybrid micropower generator with simultaneous multi-mode energy harvesting

NASA Astrophysics Data System (ADS)

Uluşan, H.; Chamanian, S.; Pathirana, W. P. M. R.; Zorlu, Ö.; Muhtaroğlu, A.; Külah, H.

2018-01-01

This study presents a triple hybrid energy harvesting system that combines harvested power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters into a single DC supply. A power management circuit is designed and implemented in 180 nm standard CMOS technology based on the distinct requirements of each harvester, and is terminated with a Schottky diode to avoid reverse current flow. The system topology hence supports simultaneous power generation and delivery from low and high frequency vibrations as well as temperature differences in the environment. The ultra-low DC voltage harvested from TE generator is boosted with a cross-coupled charge-pump driven by an LC oscillator with fully-integrated center-tapped differential inductors. The EM harvester output was rectified with a self-powered and low drop-out AC/DC doubler circuit. The PZT interface electronics benefits from peak-to-peak cycle of the harvested voltage through a negative voltage converter followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The hybrid system was tested with a wearable in-house EM energy harvester placed wrist of a jogger, a commercial low volume PZT harvester, and DC supply as the TE generator output. The system generates more than 1.2 V output for load resistances higher than 50 kΩ, which corresponds to 24 μW to power wearable sensors. Simultaneous multi-mode operation achieves higher voltage and power compared to stand-alone harvesting circuits, and generates up to 110 μW of output power. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.

Cyclooxygenase-2-issued prostaglandin e(2) enhances the production of endogenous IL-10, which down-regulates dendritic cell functions.

PubMed

Harizi, Hedi; Juzan, Monique; Pitard, Vincent; Moreau, Jean-François; Gualde, Norbert

2002-03-01

PGE(2) is a well-known immunomodulator produced in the immune response by APCs, such as dendritic cells (DCs), the most potent APC of the immune system. We investigated the PGE(2) biosynthetic capacity of bone marrow-derived DC (BM-DC) and the effects of PG on the APC. We observed that BM-DC produce PGE(2) and other proinflammatory mediators, such as leukotriene B(4) and NO, after LPS exposure. Constitutively present in BM-DC, cyclooxygenase (COX)-1 did not contribute significantly to the total pool of PGE(2) compared with the LPS-induced COX-2-produced PGE(2). Treatment of BM-DC with exogenous PGE(2) induced the production of large amounts of IL-10 and less IL-12p70. In addition, selective inhibition of COX-2, but not COX-1, was followed by significant decrements in PGE(2) and IL-10, a concomitant restoration of IL-12 production, and an enhancement of DC stimulatory potential. In contrast, we found no demonstrable role for leukotriene B(4) or NO. In view of the potential of PGE(2) to stimulate IL-10, we examined the possibility that the suppressive effect of PGE(2) is mediated via IL-10. We found that exogenous IL-10 inhibits IL-12p70 production in the presence of NS-398, a COX-2 selective inhibitor, while the inhibitory effects of PGE(2) were totally reversed by anti-IL-10. We conclude that COX-2-mediated PGE(2) up-regulates IL-10, which down-regulates IL-12 production and the APC function of BM-DC.

Atmospheric pollution and the prevalence of asthma: study among schoolchildren of 2 areas in Rio de Janeiro, Brazil.

PubMed

Rios, José Luiz Magalhães; Boechat, José Laerte; Sant'Anna, Clemax Couto; França, Alfeu Tavares

2004-06-01

Air pollutants have been associated with the exacerbation of respiratory diseases. They may intensify the inflammatory allergic response and airways reactivity to inhaled allergens. However, it is still not clear if air pollution contributes to the increased prevalence of asthma. To investigate if different levels of air pollution exposure can be related to differences in the prevalence of asthma. The International Study of Asthma and Allergies in Childhood (ISAAC) protocol was used to determine and compare the prevalence of asthma among schoolchildren in 2 cities of the metropolitan region of Rio de Janeiro, Brazil, Duque de Caxias (DC) and Seropédica (SR), which have different levels of atmospheric pollution. The research involved 4,064 students aged 13 to 14 years from 49 schools in DC and 1,129 from 17 schools in SR. Air pollution was evaluated by the concentration of inhalable particulate matter (PM10). ISAAC's written questionnaire was answered by 4,040 students aged 13 to 14 years in DC and 1,080 in SR. Between 1998 and 2000, the PM10 annual arithmetic mean was 124 microg/m3 in DC and 35 microg/m3 in SR (acceptable level is up to 50 microg/m3). The prevalence of wheezing ever was 35.1% in DC and 29.9% in SR (P = .001), and the prevalence of wheezing in the last 12 months was 19.0% in DC and 15.0% in SR (P = .002). In DC, 14.5% of the adolescents presented 1 to 3 crises of wheezing in the last year, whereas in SR only 11.0% presented 1 to 3 crises (P = .003). In this study, the prevalence of asthma in adolescents was directly related to atmospheric pollution.

Infraslow Electroencephalographic and Dynamic Resting State Network Activity.

PubMed

Grooms, Joshua K; Thompson, Garth J; Pan, Wen-Ju; Billings, Jacob; Schumacher, Eric H; Epstein, Charles M; Keilholz, Shella D

2017-06-01

A number of studies have linked the blood oxygenation level dependent (BOLD) signal to electroencephalographic (EEG) signals in traditional frequency bands (δ, θ, α, β, and γ), but the relationship between BOLD and its direct frequency correlates in the infraslow band (<1 Hz) has been little studied. Previously, work in rodents showed that infraslow local field potentials play a role in functional connectivity, particularly in the dynamic organization of large-scale networks. To examine the relationship between infraslow activity and network dynamics in humans, direct current (DC) EEG and resting state magnetic resonance imaging data were acquired simultaneously. The DC EEG signals were correlated with the BOLD signal in patterns that resembled resting state networks. Subsequent dynamic analysis showed that the correlation between DC EEG and the BOLD signal varied substantially over time, even within individual subjects. The variation in DC EEG appears to reflect the time-varying contribution of different resting state networks. Furthermore, some of the patterns of DC EEG and BOLD correlation are consistent with previous work demonstrating quasiperiodic spatiotemporal patterns of large-scale network activity in resting state. These findings demonstrate that infraslow electrical activity is linked to BOLD fluctuations in humans and that it may provide a basis for large-scale organization comparable to that observed in animal studies.

Infraslow Electroencephalographic and Dynamic Resting State Network Activity

PubMed Central

Grooms, Joshua K.; Thompson, Garth J.; Pan, Wen-Ju; Billings, Jacob; Schumacher, Eric H.; Epstein, Charles M.

2017-01-01

Abstract A number of studies have linked the blood oxygenation level dependent (BOLD) signal to electroencephalographic (EEG) signals in traditional frequency bands (δ, θ, α, β, and γ), but the relationship between BOLD and its direct frequency correlates in the infraslow band (<1 Hz) has been little studied. Previously, work in rodents showed that infraslow local field potentials play a role in functional connectivity, particularly in the dynamic organization of large-scale networks. To examine the relationship between infraslow activity and network dynamics in humans, direct current (DC) EEG and resting state magnetic resonance imaging data were acquired simultaneously. The DC EEG signals were correlated with the BOLD signal in patterns that resembled resting state networks. Subsequent dynamic analysis showed that the correlation between DC EEG and the BOLD signal varied substantially over time, even within individual subjects. The variation in DC EEG appears to reflect the time-varying contribution of different resting state networks. Furthermore, some of the patterns of DC EEG and BOLD correlation are consistent with previous work demonstrating quasiperiodic spatiotemporal patterns of large-scale network activity in resting state. These findings demonstrate that infraslow electrical activity is linked to BOLD fluctuations in humans and that it may provide a basis for large-scale organization comparable to that observed in animal studies. PMID:28462586

Multiple Signaling Pathways Are Involved in the Interleukine-4 Regulated Expression of DC-SIGN in THP-1 Cell Line

PubMed Central

Jin, Changzhong; Wu, Lijuan; Li, Jie; Fang, Meixin; Cheng, Linfang; Wu, Nanping

2012-01-01

Dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) is an important pattern recognition receptor on dendritic cells (DCs), and its expression shows significant cytological and histological specificity, being interleukine-4 (IL-4) dependent. The signaling pathways through which IL-4 regulates expression of DC-SIGN are still unclear. We used phorbol 12-myristate 13-acetate- (PMA-) differentiated THP-1 cells as the in vitro model of monocyte/macrophage cells to study the signaling pathways involved in IL-4-regulated expression of DC-SIGN. We found that a high expression of DC-SIGN could be induced by IL-4 at the levels of mRNA and cell surface protein. Upregulated expression of DC-SIGN was almost completely blocked by the specific inhibitor of ERK pathway, and partly reduced by the specific inhibitors of JAK-STAT and NF-κB pathways. The activation of the three signaling pathways was directly confirmed by testing the phosphorylation of protein kinase within the cytoplasm and nucleus over time. The analysis of cis-acting elements of DC-SIGN promoter showed that the activity of DC-SIGN promoter without Ets-1 transcription factors binding site almost completely disappeared. Our results demonstrated that multiple signaling pathways are involved in IL-4 induced high expression of DC-SIGN on THP-1 cells, in which ERK pathway is the main signaling pathway and mediated by the Ets-1 transcription factors binding site. PMID:22675249

Phase I dendritic cell p53 peptide vaccine for head and neck cancer.

PubMed

Schuler, Patrick J; Harasymczuk, Malgorzata; Visus, Carmen; Deleo, Albert; Trivedi, Sumita; Lei, Yu; Argiris, Athanassios; Gooding, William; Butterfield, Lisa H; Whiteside, Theresa L; Ferris, Robert L

2014-05-01

p53 accumulation in head and neck squamous cell carcinoma (HNSCC) cells creates a targetable tumor antigen. Adjuvant dendritic cell (DC)-based vaccination against p53 was tested in a phase I clinical trial. Monocyte-derived DC from 16 patients were loaded with two modified HLA-class I p53 peptides (Arm 1), additional Th tetanus toxoid peptide (Arm 2), or additional Th wild-type (wt) p53-specific peptide (Arm 3). Vaccine DCs (vDC) were delivered to inguinal lymph nodes at three time points. vDC phenotype, circulating p53-specific T cells, and regulatory T cells (Treg) were serially monitored by flow cytometry and cytokine production by Luminex. vDC properties were compared with those of DC1 generated with an alternative maturation regimen. No grade II-IV adverse events were observed. Two-year disease-free survival of 88% was favorable. p53-specific T-cell frequencies were increased postvaccination in 11 of 16 patients (69%), with IFN-γ secretion detected in four of 16 patients. Treg frequencies were consistently decreased (P = 0.006) relative to prevaccination values. The phenotype and function of DC1 were improved relative to vDC. Adjuvant p53-specific vaccination of patients with HNSCC was safe and associated with promising clinical outcome, decreased Treg levels, and modest vaccine-specific immunity. HNSCC patients' DC required stronger maturation stimuli to reverse immune suppression and improve vaccine efficacy. ©2014 AACR.

Emissions of toxic pollutants from co-combustion of demolition and construction wood and household waste fuel blends.

PubMed

Edo, Mar; Ortuño, Núria; Persson, Per-Erik; Conesa, Juan A; Jansson, Stina

2018-07-01

Four different types of fuel blends containing demolition and construction wood and household waste were combusted in a small-scale experimental set-up to study the effect of fuel composition on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), chlorobenzenes (PCBzs), chlorophenols (PCPhs) and polycyclic aromatic hydrocarbons (PAHs). Two woody materials, commercial stemwood (ST) and demolition and construction wood (DC) were selected because of the differences in their persistent organic pollutants (POPs), ash and metals content. For household waste, we used a municipal solid waste (MSW) and a refuse-derived fuel (RDF) from MSW with 5-20 wt% and up to 5 wt% food waste content respectively. No clear effect on the formation of pollutants was observed with different food waste content in the fuel blends tested. Combustion of ST-based fuels was very inefficient which led to high PAH emissions (32 ± 3.8 mg/kg fuel ). The use of DC clearly increased the total PCDD and PCDF emissions (71 ± 26 μg/kg fuel ) and had a clear effect on the formation of toxic congeners (210 ± 87 ng WHO 2005 -TEQ/kg fuel ). The high PCDD and PCDF emissions from DC-based fuels can be attributed to the presence of material contaminants such as small pieces of metals or plastics as well as timber treated with chromated copper arsenate preservatives and pentachlorophenol in the DC source. Copyright © 2018 Elsevier Ltd. All rights reserved.

Meta-analysis of Magnetic Marker Monitoring Data to Characterize the Movement of Single Unit Dosage Forms Though the Gastrointestinal Tract Under Fed and Fasting Conditions.

PubMed

Hénin, Emilie; Bergstrand, Martin; Weitschies, Werner; Karlsson, Mats O

2016-03-01

To develop a model predicting movement of non-disintegrating single unit dosage forms (or "tablet") through the gastrointestinal tract and characterizing the effect of food intake, based on Magnetic Marker Monitoring data, allowing real-time location of a magnetically labeled formulation. Five studies including 30 individuals in 94 occasions under 3 food status were considered. The mean residence time (MRT) of the tablet and the effect of food intake in proximal (PS) and distal stomach (DS), small intestine (SI), ascending (AC), transverse (TC) and descending colon (DC) were estimated using a Markov model for probabilities of movement. Under fasting conditions, tablet MRTs were 9.4 min in PS, 10.4 in DS, 246 in SI, 545 in AC, 135 in TC, and 286 in DC. A meal taken simultaneous to tablet intake prolonged tablet MRT to 99 min in PS and to 232 in DS; probability of gastric emptying increased of 89% each hour from 2.25 h after meal. The effect of a gastroileac reflex, caused by a secondary meal, accelerated the transit from terminal SI to AC. This model-based knowledge can be used as a part of mechanism-based models for drug absorption, applied for bottom-up predictions and/or top-down estimation.

"Thunderstruck": Plasma-Polymer-Coated Porous Silicon Microparticles As a Controlled Drug Delivery System.

PubMed

McInnes, Steven J P; Michl, Thomas D; Delalat, Bahman; Al-Bataineh, Sameer A; Coad, Bryan R; Vasilev, Krasimir; Griesser, Hans J; Voelcker, Nicolas H

2016-02-01

Controlling the release kinetics from a drug carrier is crucial to maintain a drug's therapeutic window. We report the use of biodegradable porous silicon microparticles (pSi MPs) loaded with the anticancer drug camphothecin, followed by a plasma polymer overcoating using a loudspeaker plasma reactor. Homogenous "Teflon-like" coatings were achieved by tumbling the particles by playing AC/DC's song "Thunderstruck". The overcoating resulted in a markedly slower release of the cytotoxic drug, and this effect correlated positively with the plasma polymer coating times, ranging from 2-fold up to more than 100-fold. Ultimately, upon characterizing and verifying pSi MP production, loading, and coating with analytical methods such as time-of-flight secondary ion mass spectrometry, scanning electron microscopy, thermal gravimetry, water contact angle measurements, and fluorescence microscopy, human neuroblastoma cells were challenged with pSi MPs in an in vitro assay, revealing a significant time delay in cell death onset.

Reduction of Decoy Receptor 3 Enhances TRAIL-Mediated Apoptosis in Pancreatic Cancer

PubMed Central

Wang, Wei; Yang, Shanmin; Su, Ying; Zhang, Hengshan; Liu, Chaomei; Li, Xinfeng; Lin, Ling; Kim, Sunghee; Okunieff, Paul; Zhang, Zhenhuan; Zhang, Lurong

2013-01-01

Most human pancreatic cancer cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the mechanisms by which pancreatic cancer cells utilize their extracellular molecules to counteract the proapoptotic signaling mediated by the TNF family are largely unknown. In this study, we demonstrate for the first time that DcR3, a secreted decoy receptor that malignant pancreatic cancer cells express at a high level, acts as an extracellular antiapoptotic molecule by binding to TRAIL and counteracting its death-promoting function. The reduction of DcR3 with siRNA unmasked TRAIL and greatly enhanced TRAIL-induced apoptosis. Gemcitabine, a first-line drug for pancreatic cancer, also reduced the level of DcR3. The addition of DcR3 siRNA further enhanced gemcitabine-induced apoptosis. Notably, our in vivo study demonstrated that the therapeutic effect of gemcitabine could be enhanced via further reduction of DcR3, suggesting that downregulation of DcR3 in tumor cells could tip the balance of pancreatic cells towards apoptosis and potentially serve as a new strategy for pancreatic cancer therapy. PMID:24204567

Reduction of decoy receptor 3 enhances TRAIL-mediated apoptosis in pancreatic cancer.

PubMed

Wang, Wei; Zhang, Mei; Sun, Weimin; Yang, Shanmin; Su, Ying; Zhang, Hengshan; Liu, Chaomei; Li, Xinfeng; Lin, Ling; Kim, Sunghee; Okunieff, Paul; Zhang, Zhenhuan; Zhang, Lurong

2013-01-01

Most human pancreatic cancer cells are resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. However, the mechanisms by which pancreatic cancer cells utilize their extracellular molecules to counteract the proapoptotic signaling mediated by the TNF family are largely unknown. In this study, we demonstrate for the first time that DcR3, a secreted decoy receptor that malignant pancreatic cancer cells express at a high level, acts as an extracellular antiapoptotic molecule by binding to TRAIL and counteracting its death-promoting function. The reduction of DcR3 with siRNA unmasked TRAIL and greatly enhanced TRAIL-induced apoptosis. Gemcitabine, a first-line drug for pancreatic cancer, also reduced the level of DcR3. The addition of DcR3 siRNA further enhanced gemcitabine-induced apoptosis. Notably, our in vivo study demonstrated that the therapeutic effect of gemcitabine could be enhanced via further reduction of DcR3, suggesting that downregulation of DcR3 in tumor cells could tip the balance of pancreatic cells towards apoptosis and potentially serve as a new strategy for pancreatic cancer therapy.

Plasmacytoid Dendritic Cells Suppress HIV-1 Replication but Contribute to HIV-1 Induced Immunopathogenesis in Humanized Mice

PubMed Central

Li, Guangming; Cheng, Menglan; Nunoya, Jun-ichi; Cheng, Liang; Guo, Haitao; Yu, Haisheng; Liu, Yong-jun; Su, Lishan; Zhang, Liguo

2014-01-01

The role of plasmacytoid dendritic cells (pDC) in human immunodeficiency virus type 1 (HIV-1) infection and pathogenesis remains unclear. HIV-1 infection in the humanized mouse model leads to persistent HIV-1 infection and immunopathogenesis, including type I interferons (IFN-I) induction, immune-activation and depletion of human leukocytes, including CD4 T cells. We developed a monoclonal antibody that specifically depletes human pDC in all lymphoid organs in humanized mice. When pDC were depleted prior to HIV-1 infection, the induction of IFN-I and interferon-stimulated genes (ISGs) were abolished during acute HIV-1 infection with either a highly pathogenic CCR5/CXCR4-dual tropic HIV-1 or a standard CCR5-tropic HIV-1 isolate. Consistent with the anti-viral role of IFN-I, HIV-1 replication was significantly up-regulated in pDC-depleted mice. Interestingly, the cell death induced by the highly pathogenic HIV-1 isolate was severely reduced in pDC-depleted mice. During chronic HIV-1 infection, depletion of pDC also severely reduced the induction of IFN-I and ISGs, associated with elevated HIV-1 replication. Surprisingly, HIV-1 induced depletion of human immune cells including T cells in lymphoid organs, but not the blood, was reduced in spite of the increased viral replication. The increased cell number in lymphoid organs was associated with a reduced level of HIV-induced cell death in human leukocytes including CD4 T cells. We conclude that pDC play opposing roles in suppressing HIV-1 replication and in promoting HIV-1 induced immunopathogenesis. These findings suggest that pDC-depletion and IFN-I blockade will provide novel strategies for treating those HIV-1 immune non-responsive patients with persistent immune activation despite effective anti-retrovirus treatment. PMID:25077616

Using three-phase theory-based formative research to explore healthy eating in Australian truck drivers.

PubMed

Vayro, Caitlin; Hamilton, Kyra

2016-03-01

In Australia, fruit and vegetable consumption is lower than recommended while discretionary foods (i.e., foods high in fat, sugar, and salt) are eaten in excess. Long-haul truck drivers are a group at risk of unhealthy eating but have received limited attention in the health literature. We aimed to examine long-haul truck drivers eating decisions in order to develop theory-based and empirically-driven health messages to improve their healthy food choices. Drawing on the Theory of Planned Behavior, three-phased formative research was conducted using self-report surveys. Phase 1 (N = 30, Mage = 39.53, SDage = 10.72) identified modal salient beliefs about fruit and vegetable (FV) intake and limiting discretionary choices (DC). There were nine behavioral and seven normative beliefs elicited for both FV and DC; while nine and five control beliefs were elicited for FV and DC, respectively. Phase 2 (N = 148, Mage = 44.23, SDage = 12.08) adopted a prospective design with one week follow-up to examine the predictors of FV and DC intention and behavior. A variety of behavioral and control beliefs were predictive of FV and DC intention and behavior. Normative beliefs were predictive of FV intention and behavior and DC intention only. Phase 3 (N = 20, Mage = 46.9, SDage = 12.85) elicited the reasons why each belief is held/solutions to negative beliefs, that could be used as health messages. In total, 40 reasons/solutions were identified: 26 for FV and 14 for DC. In summary, we found that specific behavioral, normative and control beliefs influenced FV and DC eating decisions. These results have implications for truck driver's health and provide formative research to inform future interventions to improve the food choices of a unique group who are at risk of unhealthy eating behaviors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Local digital control of power electronic converters in a dc microgrid based on a-priori derivation of switching surfaces

NASA Astrophysics Data System (ADS)

Banerjee, Bibaswan

In power electronic basedmicrogrids, the computational requirements needed to implement an optimized online control strategy can be prohibitive. The work presented in this dissertation proposes a generalized method of derivation of geometric manifolds in a dc microgrid that is based on the a-priori computation of the optimal reactions and trajectories for classes of events in a dc microgrid. The proposed states are the stored energies in all the energy storage elements of the dc microgrid and power flowing into them. It is anticipated that calculating a large enough set of dissimilar transient scenarios will also span many scenarios not specifically used to develop the surface. These geometric manifolds will then be used as reference surfaces in any type of controller, such as a sliding mode hysteretic controller. The presence of switched power converters in microgrids involve different control actions for different system events. The control of the switch states of the converters is essential for steady state and transient operations. A digital memory look-up based controller that uses a hysteretic sliding mode control strategy is an effective technique to generate the proper switch states for the converters. An example dcmicrogrid with three dc-dc boost converters and resistive loads is considered for this work. The geometric manifolds are successfully generated for transient events, such as step changes in the loads and the sources. The surfaces corresponding to a specific case of step change in the loads are then used as reference surfaces in an EEPROM for experimentally validating the control strategy. The required switch states corresponding to this specific transient scenario are programmed in the EEPROM as a memory table. This controls the switching of the dc-dc boost converters and drives the system states to the reference manifold. In this work, it is shown that this strategy effectively controls the system for a transient condition such as step changes in the loads for the example case.

Chaos control for the output-constrained system by using adaptive dynamic surface technology and application to the brushless DC motor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Shaohua, E-mail: hua66com@163.com; School of Automation, Chongqing University, Chongqing 400044; Hou, Zhiwei

2015-12-15

In this paper, chaos control is proposed for the output- constrained system with uncertain control gain and time delay and is applied to the brushless DC motor. Using the dynamic surface technology, the controller overcomes the repetitive differentiation of backstepping and boundedness hypothesis of pre-determined control gain by incorporating radial basis function neural network and adaptive technology. The tangent barrier Lyapunov function is employed for time-delay chaotic system to prevent constraint violation. It is proved that the proposed control approach can guarantee asymptotically stable in the sense of uniformly ultimate boundedness without constraint violation. Finally, the effectiveness of the proposedmore » approach is demonstrated on the brushless DC motor example.« less

Abscisic acid regulation of DC8, a carrot embryonic gene. [Daucus carota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatzopoulos, P.; Fong, F.; Sung, Z.R.

1990-10-01

DC8 encodes a hydrophylic 66 kilodalton protein located in the cytoplasm and cell walls of carrot (Daucus carota) embryo and endosperm. During somatic embryogenesis, the levels of DC8 mRNA and protein begin to increase 5 days after removal of auxin. To study the role of abscisic acid (ABA) in the regulation of DC8 gene, fluridone, 1-methyl-3-phenyl,-5(3-trifluoro-methyl-phenyl)-4(1H)-pyridinone, was used to inhibit the endogenous ABA content of the embryos. Fluridone, 50 micrograms per milliliter, effectively inhibits the accumulation of ABA in globular-tage embryos. Western and Northern analysis show that when fluridone is added to the culture medium DC8 protein and mRNA decreasemore » to very low levels. ABA added to fluridone supplemented culture media restores the DC8 protein and mRNA to control levels. Globular-stage embryos contain 0.9 to 1.4 {times} 10{sup {minus}7} molar ABA while 10{sup {minus}6} molar exogenously supplied ABA is the optimal concentration for restoration of DC8 protein accumulation in fluridone-treated embryos. The mRNA level is increased after 15 minutes of ABA addition and reaches maximal levels by 60 minutes. Evidence is presented that, unlike other ABA-regulated genes, DC8 is not induced in nonembryonic tissues via desiccation nor addition of ABA.« less

Comparative study of 0° X-cut and Y + 36°-cut lithium niobate high-voltage sensing

NASA Astrophysics Data System (ADS)

Patel, N.; Branch, D. W.; Schamiloglu, E.; Cular, S.

2015-08-01

A comparison study between Y + 36° and 0° X-cut lithium niobate (LiNbO3) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y + 36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5 μs voltage pulses to both crystals, the voltage-induced shift scaled linearly with voltage. For the Y + 36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz-100 kHz. Using the same conditions as the Y + 36° cut, the 0° X-cut crystal sensed a shift of 10-273 ps for DC voltages and 189-813 ps for AC voltage application. For 5 μs voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250-2 ns and the Y + 36°-cut crystal sensed a time shift of 0.115-1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. When the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment.

Comparative study of 0° X-cut and Y + 36°-cut lithium niobate high-voltage sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, N.; Department of Electrical and Computer Engineering, MSC01 1100, University of New Mexico, Albuquerque, New Mexico 87131-0001; Branch, D. W.

2015-08-15

A comparison study between Y + 36° and 0° X-cut lithium niobate (LiNbO{sub 3}) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y + 36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5more » μs voltage pulses to both crystals, the voltage-induced shift scaled linearly with voltage. For the Y + 36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz–100 kHz. Using the same conditions as the Y + 36° cut, the 0° X-cut crystal sensed a shift of 10–273 ps for DC voltages and 189–813 ps for AC voltage application. For 5 μs voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250–2 ns and the Y + 36°-cut crystal sensed a time shift of 0.115–1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. When the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment.« less

Comparative study of 0° X-cut and Y+36°-cut lithium niobate high-voltage sensing

DOE PAGES

Patel, N.; Branch, D. W.; Schamiloglu, E.; ...

2015-08-11

A comparison study between Y+36° and 0° X-cut lithium niobate (LiNbO 3) was performed to evaluate the influence of crystal cut on the acoustic propagation to realize a piezoelectric high-voltage sensor. The acoustic time-of-flight for each crystal cut was measured when applying direct current (DC), alternating current (AC), and pulsed voltages. Results show that the voltage-induced shift in the acoustic wave propagation time scaled quadratically with voltage for DC and AC voltages applied to X-cut crystals. For the Y+36° crystal, the voltage-induced shift scales linearly with DC voltages and quadratically with AC voltages. When applying 5 μs voltage pulses tomore » both crystals, the voltage-induced shift scaled linearly with voltage. For the Y+36° cut, the voltage-induced shift from applying DC voltages ranged from 10 to 54 ps and 35 to 778 ps for AC voltages at 640 V over the frequency range of 100 Hz–100 kHz. Using the same conditions as the Y+36° cut, the 0° X-cut crystal sensed a shift of 10–273 ps for DC voltages and 189–813 ps for AC voltage application. For 5 μs voltage pulses, the 0° X-cut crystal sensed a voltage induced shift of 0.250–2 ns and the Y+36°-cut crystal sensed a time shift of 0.115–1.6 ns. This suggests a frequency sensitive response to voltage where the influence of the crystal cut was not a significant contributor under DC, AC, or pulsed voltage conditions. The measured DC data were compared to a 1-D impedance matrix model where the predicted incremental length changed as a function of voltage. Furthermore, when the voltage source error was eliminated through physical modeling from the uncertainty budget, the combined uncertainty of the sensor (within a 95% confidence interval) decreased to 0.0033% using a Y + 36°-cut crystal and 0.0032% using an X-cut crystal for all the voltage conditions used in this experiment.« less

7 CFR 1724.54 - Requirements for RUS approval of plans and specifications.

Code of Federal Regulations, 2010 CFR

2010-01-01

... paragraph (e) covers all portions of a generating plant including plant buildings, the generator step-up... States Department of Agriculture, Stop 1522, 1400 Independence Ave., SW., Washington, DC 20250-1522. The...

Compatibility of an Ultraselective Microcatheter and Epirubicin Loaded 300–500-μm DC Bead in Ex Vivo Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukuoka, Yasushi, E-mail: miyano.y.fukuoka@gmail.com; Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp; Nishiofuku, Hideyuki, E-mail: nishiofukuhideyuki@yahoo.co.jp

PurposeThe purpose of this study is to examine whether epirubicin loaded DC Bead 300–500 μm in size can pass through a 1.8-Fr ultraselective microcatheter in ex vivo study.MethodsEpirubicin (25 mg/1 mL) loaded 100–300 and 300–500 μm DC Bead were tested. Both sizes were diluted 5, 10, and 30 times using contrast material. Ultraselective microcatheter with the outer diameter of 1.8 Fr and the inner diameter of .017 inch (431.8 μm) was used. The diluted DC Bead was injected at a speed of 1 mL/min, and the pressure was continuously measured. The microspheres’ shapes after ejection were observed by a stereomicroscope.ResultsThe maximum pressure of contrast material alone was 8.40 ± 0.21 psi.more » The maximum pressure in 5, 10, and 30 times dilution groups of 100–300 μm were 9.67 ± 1.18, 9.25 ± 0.25, and 9.71 ± 0.28 psi, respectively, whereas 21.10 ± 10.2, 10.48 ± 2.14, 10.09 ± 0.37 psi, respectively in 300–500 μm groups. The maximum pressure in 5 times dilution group of 300–500 μm was significantly higher than the other groups (P < 0.05). In 300–500 μm, 4 of 10 measurements showed high pressure over 24 psi (the maximum value was 43.5 psi) in 5 times dilution group, whereas in 10 times and 30 times dilution groups, all measurements showed less than 12 psi. No damages of microspheres were found.ConclusionsEpirubicin loaded DC Bead 300–500 μm in size can pass through a 1.8-Fr ultraselective microcatheter. To avoid high resistance due to microspheres’ aggregation, dilution more than 10 times is needed.« less

Optimization of direct current-enhanced radiofrequency ablation: an ex vivo study.

PubMed

Tanaka, Toshihiro; Isfort, Peter; Bruners, Philipp; Penzkofer, Tobias; Kichikawa, Kimihiko; Schmitz-Rode, Thomas; Mahnken, Andreas H

2010-10-01

The purpose of this study was to investigate the optimal setting for radiofrequency (RF) ablation combined with direct electrical current (DC) ablation in ex vivo bovine liver. An electrical circuit combining a commercially available RF ablation system with DC was developed. The negative electrode of a rectifier that provides DC was connected to a 3-cm multitined expandable RF probe. A 100-mH inductor was used to prevent electrical leakage from the RF generator. DC was applied for 15 min and followed by RF ablation in freshly excised bovine livers. Electric current was measured by an ammeter. Coagulation volume, ablation duration, and mean amperage were assessed for various DC voltages (no DC, 2.2, 4.5, and 9.0 V) and different RF ablation protocols (stepwise increase from 40 to 80 W, 40 W fixed, and 80 W fixed). Results were compared using Kruskal-Wallis and Mann-Whitney U test. Applying DC with 4.5 or 9.0 V, in combination with 40 W fixed or a stepwise increase of RF energy, resulted in significantly increased zone of ablation size compared with 2.2 V or no DC (P = 0.009). At 4.5 V DC, the stepwise increase of RF energy resulted in the same necrosis size as a 40 W fixed protocol (26.6 +/- 3.9 vs. 26.5 +/- 4.0 ml), but ablation duration was significantly decreased (296 +/- 85 s vs. 423 +/- 104 s; P = 0.028). Mean amperage was significantly lower at 4.5 V compared with 9.0 V (P = 0.028). Combining a stepwise increase of RF energy with a DC voltage of 4.5 V is most appropriate to increase coagulation volume and to minimize procedure time.

Sliding-mode control of single input multiple output DC-DC converter

NASA Astrophysics Data System (ADS)

Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

2016-10-01

Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

Stress-Induced Accumulation of DcAOX1 and DcAOX2a Transcripts Coincides with Critical Time Point for Structural Biomass Prediction in Carrot Primary Cultures (Daucus carota L.)

PubMed Central

Campos, M. Doroteia; Nogales, Amaia; Cardoso, Hélia G.; Kumar, Sarma R.; Nobre, Tânia; Sathishkumar, Ramalingam; Arnholdt-Schmitt, Birgit

2016-01-01

Stress-adaptive cell plasticity in target tissues and cells for plant biomass growth is important for yield stability. In vitro systems with reproducible cell plasticity can help to identify relevant metabolic and molecular events during early cell reprogramming. In carrot, regulation of the central root meristem is a critical target for yield-determining secondary growth. Calorespirometry, a tool previously identified as promising for predictive growth phenotyping has been applied to measure the respiration rate in carrot meristem. In a carrot primary culture system (PCS), this tool allowed identifying an early peak related with structural biomass formation during lag phase of growth, around the 4th day of culture. In the present study, we report a dynamic and correlated expression of carrot AOX genes (DcAOX1 and DcAOX2a) during PCS lag phase and during exponential growth. Both genes showed an increase in transcript levels until 36 h after explant inoculation, and a subsequent down-regulation, before the initiation of exponential growth. In PCS growing at two different temperatures (21°C and 28°C), DcAOX1 was also found to be more expressed in the highest temperature. DcAOX genes’ were further explored in a plant pot experiment in response to chilling, which confirmed the early AOX transcript increase prior to the induction of a specific anti-freezing gene. Our findings point to DcAOX1 and DcAOX2a as being reasonable candidates for functional marker development related to early cell reprogramming. While the genomic sequence of DcAOX2a was previously described, we characterize here the complete genomic sequence of DcAOX1. PMID:26858746

Modulation of dendritic cell maturation and function by the Tax protein of human T cell leukemia virus type 1

PubMed Central

Jain, Pooja; Ahuja, Jaya; Khan, Zafar K.; Shimizu, Saori; Meucci, Olimpia; Jennings, Stephen R.; Wigdahl, Brian

2009-01-01

Human T cell leukemia virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is characterized by the generation of an intense CTL cell response directed against the viral transactivator protein Tax. In addition, patients diagnosed with HAM/TSP exhibit rapid activation and maturation of dendritic cells (DC), likely contributing to the robust, Tax-specific CTL response. In this study, extracellular Tax has been shown to induce maturation and functional alterations in human monocyte-derived DC, critical observations being confirmed in freshly isolated myeloid DC. Tax was shown to promote the production of proinflammatory cytokines and chemokines involved in the DC activation process in a dose- and time-dependent manner. Furthermore, Tax induced the expression of DC activation (CD40, CD80, and CD86) and maturation (CD83) markers and enhanced the T cell proliferation capability of DC. Heat inactivation of Tax resulted in abrogation of these effects, indicating a requirement for the native structure of Tax, which was found to bind efficiently to the DC membrane and was internalized within a few hours, suggesting that extracellular Tax may possess an intracellular mechanism of action subsequent to entry. Finally, inhibitors of cellular signaling pathways, NF-κB, protein kinase, tyrosine kinase, and phospholipase C, were shown to inhibit Tax-mediated DC activation. This is the first study reporting the immunomodulatory effects of extracellular Tax in the DC compartment. These results suggest that DC, once exposed to Tax by uptake from the extracellular environment, can undergo activation, providing constant antigen presentation and costimulation to T cells, leading to the intense T cell proliferation and inflammatory responses underlying HAM/TSP. PMID:17442856

Sliding-mode control of single input multiple output DC-DC converter.

PubMed

Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

2016-10-01

Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

Optimization of Direct Current-Enhanced Radiofrequency Ablation: An Ex Vivo Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp; Isfort, Peter; Bruners, Philipp

2010-10-15

The purpose of this study was to investigate the optimal setting for radiofrequency (RF) ablation combined with direct electrical current (DC) ablation in ex vivo bovine liver. An electrical circuit combining a commercially available RF ablation system with DC was developed. The negative electrode of a rectifier that provides DC was connected to a 3-cm multitined expandable RF probe. A 100-mH inductor was used to prevent electrical leakage from the RF generator. DC was applied for 15 min and followed by RF ablation in freshly excised bovine livers. Electric current was measured by an ammeter. Coagulation volume, ablation duration, andmore » mean amperage were assessed for various DC voltages (no DC, 2.2, 4.5, and 9.0 V) and different RF ablation protocols (stepwise increase from 40 to 80 W, 40 W fixed, and 80 W fixed). Results were compared using Kruskal-Wallis and Mann-Whitney U test. Applying DC with 4.5 or 9.0 V, in combination with 40 W fixed or a stepwise increase of RF energy, resulted in significantly increased zone of ablation size compared with 2.2 V or no DC (P = 0.009). At 4.5 V DC, the stepwise increase of RF energy resulted in the same necrosis size as a 40 W fixed protocol (26.6 {+-} 3.9 vs. 26.5 {+-} 4.0 ml), but ablation duration was significantly decreased (296 {+-} 85 s vs. 423 {+-} 104 s; P = 0.028). Mean amperage was significantly lower at 4.5 V compared with 9.0 V (P = 0.028). Combining a stepwise increase of RF energy with a DC voltage of 4.5 V is most appropriate to increase coagulation volume and to minimize procedure time.« less

78 FR 10001 - Proposed Collection; Comment Request for Regulation Project

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-12

... Lawrence, Internal Revenue Service, room 6129, 1111 Constitution Avenue NW., Washington, DC 20224. FOR...., Washington, DC 20224, or at (202) 622-3186, or through the Internet at katherine.b[email protected] provides a timely Form W-2 or 1099, as appropriate. Current Actions: There is no change to this existing...

77 FR 26300 - Center for Scientific Review; Notice of Closed Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-03

... review and evaluate grant applications. Place: Ritz Carlton Hotel, 1150 22nd Street NW., Washington, DC.... Time: 8:00 a.m. to 6:00 p.m. Agenda: To review and evaluate grant applications. Place: Pier 5 Hotel.... Place: Melrose Hotel, 2430 Pennsylvania Avenue NW., Washington, DC 20037. Contact Person: Samuel C...

75 FR 10216 - The Manufacturing Council: Meeting of the Manufacturing Council

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-05

...: March 22, 2010. Time: 1:30-3 p.m. (ET). ADDRESSES: Department of Commerce, 1401 Constitution Avenue, NW... Manufacturing Council, Room 4043, 1401 Constitution Avenue, NW., Washington, DC, 20230, telephone 202-482-4501..., Room 4043, 1401 Constitution Avenue, NW., Washington, DC, 20230, telephone: 202-482-4501, e-mail: Marc...

Shock Spectrum Calculation from Acceleration Time Histories

DTIC Science & Technology

1980-09-01

CLASSIFICATIONe OF THIS PAGE (Uh-e DOg ~ 9--t)____________________ REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM I. REPRT NU9911ACCUIISIO6 NO .3ASCCSPICHT’S...SCE. Oakland CA NAVSCOLCECOFF C35 Port Hueneme. CA,. CO, Code C44A Porn Hueneme. CA NAVSEASYSCOM Code 05M13 (Newhouse) Wash DC; Code 6212, Wash DC

Reduction in blood pressure and serum lipids by lycosome formulation of dark chocolate and lycopene in prehypertension.

PubMed

Petyaev, Ivan M; Dovgalevsky, Pavel Y; Chalyk, Natalia E; Klochkov, Victor; Kyle, Nigel H

2014-11-01

Twenty-nine healthy volunteers aged 47-69 years old were randomly assigned to a 28-day oral intake of different dark chocolate (DC) formulations. The main group received daily 30 g of proprietary lycopene-containing (L-tug) lycosome formulation of DC with enhanced bioavailability of cocoa flavanols. Two control groups daily consumed either 30 g of regular DC alone or along with 7 mg of lycopene, which corresponds to the amount of lycopene ingested with L-tug formulation. It was found that L-tug was more efficient in reducing diastolic blood pressure (mean value of -6.22 mmHg, 95% CI: 5.00, 8.00) when compared with the regular DC group (-3.00 mmHg, P < 0.05) or the group which ingested the DC and lycopene as two separate formulations (mean reduction of -4 mmHg, 95% CI: 2.47, 6.00, P = 0.0262). Only marginal superiority for L-tug formulation in the reduction in systolic blood pressure was seen. However, the L-tug formulation was the only formulation of DC which affected serum lipids. There was a reduction in total cholesterol (from median 228.00 mg/dL [95% CI: 206.2, 242.5] to 187.00 mg/dL [95% CI: 166.2, 202.2, P < 0.05]) with corresponding decline of low-density lipoprotein (LDL) cholesterol (from a median of 166.00 mg/dL [95% CI: 130.8, 177.0] to 151.00 mg/dL [95% CI: 122.8, 167.4; P < 0.05]) at the end of the intervention period. Similar decline was seen in serum triglycerides (P < 0.05). Serum high-density lipoprotein (HDL) cholesterol, glucose levels, and C-reactive protein (CRP) values remained statistically unchanged in all study groups throughout the intervention period. A superior biological activity of the L-tug lycosome formulation of DC extending beyond its antihypertensive effect to lipid-lowering ability opens up new possibilities for the use of DC for health purposes helping to reduce daily caloric intake without compromising on the health benefits of DC consumption.

Design of single-winding energy-storage reactors for dc-to-dc converters using air-gapped magnetic-core structures

NASA Technical Reports Server (NTRS)

Ohri, A. K.; Wilson, T. G.; Owen, H. A., Jr.

1977-01-01

A procedure is presented for designing air-gapped energy-storage reactors for nine different dc-to-dc converters resulting from combinations of three single-winding power stages for voltage stepup, current stepup and voltage stepup/current stepup and three controllers with control laws that impose constant-frequency, constant transistor on-time and constant transistor off-time operation. The analysis, based on the energy-transfer requirement of the reactor, leads to a simple relationship for the required minimum volume of the air gap. Determination of this minimum air gap volume then permits the selection of either an air gap or a cross-sectional core area. Having picked one parameter, the minimum value of the other immediately leads to selection of the physical magnetic structure. Other analytically derived equations are used to obtain values for the required turns, the inductance, and the maximum rms winding current. The design procedure is applicable to a wide range of magnetic material characteristics and physical configurations for the air-gapped magnetic structure.

Requirements for a transformerless power conditioning system

NASA Technical Reports Server (NTRS)

Klein, J.; Koerner, T.; Rippel, W.; Kalbach, J.

1984-01-01

Requirements for development of a Transformerless Power Conditioning Subsystem (TPCS) that will meet utility, manufacturer, and customer needs are detailed. Issues analyzed include current utility guidelines, safety and grounding issues that appear as local codes, various kinds of TPCS connections that can be developed, dc injection, and a brief survey of TPCS circuit topologies that will meet requirements. The major result is that a finite time exists for control operation before dc injection into the distribution transformer causes customer outage (on the order of seconds). This time permits the control system to sense a dc injection condition and remove the TPCS from the utility system. Requirements for such a control system are specified. A three wire connection will ensure balanced operation for customer loads and two wire connections caused average value dc to be injected into single phase loads. This type of connection also allows for the lowest array voltage. The conclusion is that requirements for a TPCS can be determined and that there are not showstopping issues preventing implementation. The actual design and topology of the TPCS was left for further study.

Evaluation of the dependence of CEST-EPI measurement on repetition time, RF irradiation duty cycle and imaging flip angle for enhanced pH sensitivity

NASA Astrophysics Data System (ADS)

Zhe Sun, Phillip; Lu, Jie; Wu, Yin; Xiao, Gang; Wu, Renhua

2013-09-01

Chemical exchange saturation transfer (CEST) is a magnetic resonance imaging (MRI) contrast mechanism that can detect dilute CEST agents and microenvironmental properties, with a host of promising applications. Experimental measurement of the CEST effect is complex, and depends on not only CEST agent concentration and exchange rate, but also experimental parameters such as RF irradiation amplitude and scheme. Although echo planar imaging (EPI) has been increasingly used for CEST MRI, the relationship between CEST effect and repetition time (TR), RF irradiation duty cycle (DC) and EPI flip angle (α) has not been fully evaluated and optimized to enhance CEST MRI sensitivity. In addition, our study evaluated gradient echo CEST-EPI by quantifying the CEST effect and its signal-to-noise ratio per unit time (SNRput) as functions of TR, DC and α. We found that CEST effect increased with TR and DC but decreased with α. Importantly, we found that SNRput peaked at intermediate TRs of about twice the T1 and α, at approximately 75°, and increased with RF DC. The simulation results were validated using a dual-pH creatine-gel CEST phantom. In summary, our study provides a useful framework for optimizing CEST MRI experiments.

Annual Consumer Education "Catch-Up" Conference. (3rd, Washington, D.C., March 2-3, 1978).

ERIC Educational Resources Information Center

Office of Consumer Affairs, Washington, DC.

As stated in the introductory summary to these proceedings, the goals of the third annual national conference for consumer education were (1) to provide an introduction to resources and materials for persons new to the field of consumer education, (2) to highlight successful programs, (3) to provide up-to-date information on consumer legislation…