Stochastic resonance energy harvesting for a rotating shaft subject to random and periodic vibrations: influence of potential function asymmetry and frequency sweep

NASA Astrophysics Data System (ADS)

Kim, Hongjip; Che Tai, Wei; Zhou, Shengxi; Zuo, Lei

2017-11-01

Stochastic resonance is referred to as a physical phenomenon that is manifest in nonlinear systems whereby a weak periodic signal can be significantly amplified with the aid of inherent noise or vice versa. In this paper, stochastic resonance is considered to harvest energy from two typical vibrations in rotating shafts: random whirl vibration and periodic stick-slip vibration. Stick-slip vibrations impose a constant offset in centrifugal force and distort the potential function of the harvester, leading to potential function asymmetry. A numerical analysis based on a finite element method was conducted to investigate stochastic resonance with potential function asymmetry. Simulation results revealed that a harvester with symmetric potential function generates seven times higher power than that with asymmetric potential function. Furthermore, a frequency-sweep analysis also showed that stochastic resonance has hysteretic behavior, resulting in frequency difference between up-sweep and down-sweep excitations. An electromagnetic energy harvesting system was constructed to experimentally verify the numerical analysis. In contrast to traditional stochastic resonance harvesters, the proposed harvester uses magnetic force to compensate the offset in the centrifugal force. System identification was performed to obtain the parameters needed in the numerical analysis. With the identified parameters, the numerical simulations showed good agreement with the experiment results with around 10% error, which verified the effect of potential function asymmetry and frequency sweep excitation condition on stochastic resonance. Finally, attributed to compensating the centrifugal force offset, the proposed harvester generated nearly three times more open-circuit output voltage than its traditional counterpart.

Guide for the Assessment of the Vapor Intrusion Pathway

DTIC Science & Technology

2006-02-01

variability. There are two basic types of flux chambers: the static chamber and the dynamic chamber. The static chamber does not use "sweep" gas to maintain...DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED I February 2006 FINAL 4. TITLE AND SUBTITLE 5. FUNDING...sites, the problem is typically limited to a handful of chemicals. This guidance will be most useful for two groups of Air Force environmental managers

Dual-gate polysilicon nanoribbon biosensors enable high sensitivity detection of proteins.

PubMed

Zeimpekis, I; Sun, K; Hu, C; Ditshego, N M J; Thomas, O; de Planque, M R R; Chong, H M H; Morgan, H; Ashburn, P

2016-04-22

We demonstrate the advantages of dual-gate polysilicon nanoribbon biosensors with a comprehensive evaluation of different measurement schemes for pH and protein sensing. In particular, we compare the detection of voltage and current changes when top- and bottom-gate bias is applied. Measurements of pH show that a large voltage shift of 491 mV pH(-1) is obtained in the subthreshold region when the top-gate is kept at a fixed potential and the bottom-gate is varied (voltage sweep). This is an improvement of 16 times over the 30 mV pH(-1) measured using a top-gate sweep with the bottom-gate at a fixed potential. A similar large voltage shift of 175 mV is obtained when the protein avidin is sensed using a bottom-gate sweep. This is an improvement of 20 times compared with the 8.8 mV achieved from a top-gate sweep. Current measurements using bottom-gate sweeps do not deliver the same signal amplification as when using bottom-gate sweeps to measure voltage shifts. Thus, for detecting a small signal change on protein binding, it is advantageous to employ a double-gate transistor and to measure a voltage shift using a bottom-gate sweep. For top-gate sweeps, the use of a dual-gate transistor enables the current sensitivity to be enhanced by applying a negative bias to the bottom-gate to reduce the carrier concentration in the nanoribbon. For pH measurements, the current sensitivity increases from 65% to 149% and for avidin sensing it increases from 1.4% to 2.5%.

Dual-gate polysilicon nanoribbon biosensors enable high sensitivity detection of proteins

NASA Astrophysics Data System (ADS)

Zeimpekis, I.; Sun, K.; Hu, C.; Ditshego, N. M. J.; Thomas, O.; de Planque, M. R. R.; Chong, H. M. H.; Morgan, H.; Ashburn, P.

2016-04-01

We demonstrate the advantages of dual-gate polysilicon nanoribbon biosensors with a comprehensive evaluation of different measurement schemes for pH and protein sensing. In particular, we compare the detection of voltage and current changes when top- and bottom-gate bias is applied. Measurements of pH show that a large voltage shift of 491 mV pH-1 is obtained in the subthreshold region when the top-gate is kept at a fixed potential and the bottom-gate is varied (voltage sweep). This is an improvement of 16 times over the 30 mV pH-1 measured using a top-gate sweep with the bottom-gate at a fixed potential. A similar large voltage shift of 175 mV is obtained when the protein avidin is sensed using a bottom-gate sweep. This is an improvement of 20 times compared with the 8.8 mV achieved from a top-gate sweep. Current measurements using bottom-gate sweeps do not deliver the same signal amplification as when using bottom-gate sweeps to measure voltage shifts. Thus, for detecting a small signal change on protein binding, it is advantageous to employ a double-gate transistor and to measure a voltage shift using a bottom-gate sweep. For top-gate sweeps, the use of a dual-gate transistor enables the current sensitivity to be enhanced by applying a negative bias to the bottom-gate to reduce the carrier concentration in the nanoribbon. For pH measurements, the current sensitivity increases from 65% to 149% and for avidin sensing it increases from 1.4% to 2.5%.

Stark cell optoacoustic detection of constituent gases in sample

NASA Technical Reports Server (NTRS)

Margolis, J. S.; Shumate, M. S. (Inventor)

1980-01-01

An optoacoustic detector for gas analysis is implemented with Stark effect cell modulation for switching a beam in and out of coincidence with a spectral line of a constituent gas in order to eliminate the heating effect of laser energy in the cell as a source of background noise. By using a multiline laser, and linearly sweeping the DC bias voltage while exciting the cell with a multiline laser, it is possible to obtain a spectrum from which to determine the combinations of excited constituents and determine their concentrations in parts per million.

Highly uniform and reliable resistive switching characteristics of a Ni/WOx/p+-Si memory device

NASA Astrophysics Data System (ADS)

Kim, Tae-Hyeon; Kim, Sungjun; Kim, Hyungjin; Kim, Min-Hwi; Bang, Suhyun; Cho, Seongjae; Park, Byung-Gook

2018-02-01

In this paper, we investigate the resistive switching behavior of a bipolar resistive random-access memory (RRAM) in a Ni/WOx/p+-Si RRAM with CMOS compatibility. Highly unifrom and reliable bipolar resistive switching characteristics are observed by a DC voltage sweeping and its switching mechanism can be explained by SCLC model. As a result, the possibility of metal-insulator-silicon (MIS) structural WOx-based RRAM's application to Si-based 1D (diode)-1R (RRAM) or 1T (transistor)-1R (RRAM) structure is demonstrated.

Cathodic Stripping Analysis Complicated by Adsorption Processes: Determination of 2-Thiouracil at a Rotating Silver Disk Electrode,

DTIC Science & Technology

1983-01-01

concentration, poten- tial sweep rate, rotation speed, deposition potential and other parameters -on the shape and height of the stripping peaks have...concentration, potential sweep rate, rotation speed, deposition potential and other parameters on the shape and height of the stripping peaks have been...of the greater surface area of a solid electrode compared to a dropping mercury electrode. Cathodic stripping voltametry at a rotating silver disk

Possibilities of creating a pure coal-fired power industry based on nanomaterials

NASA Astrophysics Data System (ADS)

Zyryanov, V. V.

2015-08-01

A concept of distributed multigeneration during combustion of homogenized solid fuels with the addition of oxygen-enriched (to 30-50%) air is proposed. To implement this concept, application of medium-temperature δ-Bi2O3/Ag-nanocermet-based membranes is suggested under low pressures and sweeping of oxygen by the cleaned exit gas or the air. The primary product of the multigeneration is microsphere materials. The heat, the AC and the DC electric energy, the cleaned exit gases with a high CO2 content, and volatile elements adsorbed by the filters are the secondary products. To completely clean the exit gases, which is necessary to implement the distributed multigeneration, an array of successive passive plants is proposed. A thermoelectric module based on a BiTeSb-skutterudite nanocomposite is effective in generation of the DC electric energy at microthermoelectric power plants.

A novel approach to pharmaco-EEG for investigating analgesics: assessment of spectral indices in single-sweep evoked brain potentials.

PubMed

Gram, Mikkel; Graversen, Carina; Nielsen, Anders K; Arendt-Nielsen, Thomas; Mørch, Carsten D; Andresen, Trine; Drewes, Asbjørn M

2013-12-01

To compare results from analysis of averaged and single-sweep evoked brain potentials (EPs) by visual inspection and spectral analysis in order to identify an objective measure for the analgesic effect of buprenorphine and fentanyl. Twenty-two healthy males were included in a randomized study to assess the changes in EPs after 110 sweeps of painful electrical stimulation to the median nerve following treatment with buprenorphine, fentanyl or placebo patches. Bone pressure, cutaneous heat and electrical pain ratings were assessed. EPs and pain assessments were obtained before drug administration, 24, 48, 72 and 144 h after beginning of treatment. Features from EPs were extracted by three different approaches: (i) visual inspection of amplitude and latency of the main peaks in the average EPs, (ii) spectral distribution of the average EPs and (iii) spectral distribution of the EPs from single-sweeps. Visual inspection revealed no difference between active treatments and placebo (all P > 0.05). Spectral distribution of the averaged potentials showed a decrease in the beta (12-32 Hz) band for fentanyl (P = 0.036), which however did not correlate with pain ratings. Spectral distribution in the single-sweep EPs revealed significant increases in the theta, alpha and beta bands for buprenorphine (all P < 0.05) as well as theta band increase for fentanyl (P = 0.05). For buprenorphine, beta band activity correlated with bone pressure and cutaneous heat pain (both P = 0.04, r = 0.90). In conclusion single-sweep spectral band analysis increases the information on the response of the brain to opioids and may be used to identify the response to analgesics. © 2013 The Authors. British Journal of Clinical Pharmacology © 2013 The British Pharmacological Society.

Switching kinetics of SiC resistive memory for harsh environments

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

Morgan, K. A., E-mail: kam2g11@soton.ac.uk; Huang, R.; Groot, C. H. de

2015-07-15

Cu/a-SiC/Au resistive memory cells are measured using voltage pulses and exhibit the highest R{sub OFF}/R{sub ON} ratio recorded for any resistive memory. The switching kinetics are investigated and fitted to a numerical model, using thermal conductivity and resistivity properties of the dielectric. The SET mechanism of the Cu/a-SiC/Au memory cells is found to be due to ionic motion without joule heating contributions, whereas the RESET mechanism is found to be due to thermally assisted ionic motion. The conductive filament diameter is extracted to be around 4nm. The high thermal conductivity and resistivity for the Cu/a-SiC/Au memory cells result in slowmore » switching but with high thermal reliability and stability, showing potential for use in harsh environments. Radiation properties of SiC memory cells are investigated. No change was seen in DC sweep or pulsed switching nor in conductive mechanisms, up to 2Mrad(Si) using {sup 60}Co gamma irradiation.« less

Single-sweep spectral analysis of contact heat evoked potentials: a novel approach to identify altered cortical processing after morphine treatment

PubMed Central

Hansen, Tine M; Graversen, Carina; Frøkjær, Jens B; Olesen, Anne E; Valeriani, Massimiliano; Drewes, Asbjørn M

2015-01-01

Aims The cortical response to nociceptive thermal stimuli recorded as contact heat evoked potentials (CHEPs) may be altered by morphine. However, previous studies have averaged CHEPs over multiple stimuli, which are confounded by jitter between sweeps. Thus, the aim was to assess single-sweep characteristics to identify alterations induced by morphine. Methods In a crossover study 15 single-sweep CHEPs were analyzed from 62 electroencephalography electrodes in 26 healthy volunteers before and after administration of morphine or placebo. Each sweep was decomposed by a continuous wavelet transform to obtain normalized spectral indices in the delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), beta (12–32 Hz) and gamma (32–80 Hz) bands. The average distribution over all sweeps and channels was calculated for the four recordings for each volunteer, and the two recordings before treatments were assessed for reproducibility. Baseline corrected spectral indices after morphine and placebo treatments were compared to identify alterations induced by morphine. Results Reproducibility between baseline CHEPs was demonstrated. As compared with placebo, morphine decreased the spectral indices in the delta and theta bands by 13% (P = 0.04) and 9% (P = 0.007), while the beta and gamma bands were increased by 10% (P = 0.006) and 24% (P = 0.04). Conclusion The decreases in the delta and theta band are suggested to represent a decrease in the pain specific morphology of the CHEPs, which indicates a diminished pain response after morphine administration. Hence, assessment of spectral indices in single-sweep CHEPs can be used to study cortical mechanisms induced by morphine treatment. PMID:25556985

Regioselective electrochemical reduction of 2,4-dichlorobiphenyl - Distinct standard reduction potentials for carbon-chlorine bonds using convolution potential sweep voltammetry

NASA Astrophysics Data System (ADS)

Muthukrishnan, A.; Sangaranarayanan, M. V.; Boyarskiy, V. P.; Boyarskaya, I. A.

2010-04-01

The reductive cleavage of carbon-chlorine bonds in 2,4-dichlorobiphenyl (PCB-7) is investigated using the convolution potential sweep voltammetry and quantum chemical calculations. The potential dependence of the logarithmic rate constant is non-linear which indicates the validity of Marcus-Hush theory of quadratic activation-driving force relationship. The ortho-chlorine of the 2,4-dichlorobiphenyl gets reduced first as inferred from the quantum chemical calculations and bulk electrolysis. The standard reduction potentials pertaining to the ortho-chlorine of 2,4-dichlorobiphenyl and that corresponding to para chlorine of the 4-chlorobiphenyl have been estimated.

Vehicle Charging on the 29.036 and 29.037 Rockets of the EQUIS II Campaign.

NASA Astrophysics Data System (ADS)

Barjatya, A.; Swenson, C.; Fish, C.; Hummel, A.; Hysell, D.

2004-12-01

The rocket investigation "Scattering Layer in the Bottomside Equatorial F-region Ionosphere", was part of the NASA EQUIS II campaign. Two salvos of sounding rockets were launched from Roi Namur in Kwajalein on August 7th and 15th of 2004. The project's mission was to investigate the thin scattering layers in the post sunset equatorial F region ionosphere that act as precursors to a fully developed equatorial spread F. Each of the salvos consisted of one instrumented and two chemical release payloads. The instrumented rockets were launched westward into equatorial spread F precursor that was first observed from ground using the Altair radar. The instrumented rockets reached an apogee of ~450 km. The instruments consisted of a Sweeping Langmuir Probe (SLP), a fixed bias DC Probe (DCP), a Plasma Impedance Probe consisting of a Plasma Frequency Probe and a Plasma Sweeping Probe built at Utah State University. The instrument suite also included an Electric Field Probe built by Penn State University. This poster presents observations of vehicle charging and preliminary data from the SLP and DCP.

Wingbeat frequency-sweep and visual stimuli for trapping male Aedes aegypti (Diptera: Culicidae)

USDA-ARS?s Scientific Manuscript database

Combinations of female wingbeat acoustic cues and visual cues were evaluated to determine their potential for use in male Aedes aegypti (L.) traps in peridomestic environments. A modified Centers for Disease control (CDC) light trap using a 350-500 Hz frequency-sweep broadcast from a speaker as an a...

Electrochemical Features of the Ferric Sulfate Leaching of CuFeS2/C Aggregates.

DTIC Science & Technology

1984-11-28

HCl at room temperature by linear sweep f’ -" !, voltametry Ai potentiostatic electrolysis. For example, they found #i j n one case that the anodic...converter and Model 175 potential sweep generator. Potentlo- * dynamic polarization experiments were designed to examine the nature :of the half-cell

Binding of Pentachloroiridite to Plasma Polymerized Vinylpyridine Films and Electrocatalytic Oxidation of Ascorbic Acid

DTIC Science & Technology

1981-12-21

anion. Voltametry in 1 M HC1 and in 1 M HC]O 4 is indis- tinguishable from that in Figure 2 except for a minor (10-20 mv.) potential shift in E rf...slope of Figure 9 agrees within a factor of 1.4 with that calculated from the irreversible potential sweep relation (36) using the known diffusion...Curve B. All in 1 M HSO4 2 ,4* Figure 9. Relationship of potential sweep rate and peak current for Curve B of Figure 6. Figure 10. Curve A: oxidation

Radiofrequency generation by coherently moving fluxons

NASA Astrophysics Data System (ADS)

Dobrovolskiy, O. V.; Sachser, R.; Huth, M.; Shklovskij, V. A.; Vovk, R. V.; Bevz, V. M.; Tsindlekht, M. I.

2018-04-01

A lattice of Abrikosov vortices in type II superconductors is characterized by a periodic modulation of the magnetic induction perpendicular to the applied magnetic field. For a coherent vortex motion under the action of a transport current, the magnetic induction at a given point of the sample varies in time with a washboard frequency fWB = v/d, where v is the vortex velocity and d is the distance between the vortices in the direction of motion. Here, by using a spectrum analyzer connected to a 50 nm-wide Au nanowire meander near the surface of a superconducting Nb film, we detect an ac voltage induced by coherently moving fluxons. The voltage is peaked at the washboard frequency, fWB, and its subharmonics, fTOF = fWB/5, determined by the antenna width. By sweeping the dc current value, we reveal that fWB can be tuned from 100 MHz to 1.5 GHz, thereby demonstrating that patterned normal metal/superconductor nanostructures can be used as dc-tunable generators operating in the radiofrequency range.

Summary of NACA/NASA Variable-Sweep Research and Development Leading to the F-111 (TFX)

NASA Technical Reports Server (NTRS)

1966-01-01

On November 24, 1962, the United States ushered in a new era of aircraft development when the Department of Defense placed an initial development contract for the world's first supersonic variable-sweep aircraft - the F-111 or so-called TFX (tactical fighter-experimental). The multimission performance potential of this concept is made possible by virtue of the variable-sweep wing - a research development of the NASA and its predecessor, the NACA. With the wing swept forward into the maximum span position, the aircraft configuration is ideal for efficient subsonic flight. This provides long-range combat and ferry mission capability, short-field landing and take-off characteristics, and compatibility with naval aircraft carrier operation. With the wing swept back to about 650 of sweep, the aircraft has optimum supersonic performance to accomplish high-altitude supersonic bombing or interceptor missions. With the wing folded still further back, the aircraft provides low drag and low gust loads during supersonic flight "on the deck" (altitudes under 1000 feet). The concept of wing variable sweep, of course, is not new. Initial studies were conducted at Langley as early as 1945, and two subsonic variable-sweep prototypes (Bell X-5 and Grumman XF-IOF) were flown as early as 1951/52. These were subsonic aircraft, however, and the great advantage of variable sweep in improving supersonic flight efficiency could not be realized. Further the structures of these early aircraft were complicated by the necessity for translating the ing fore and aft to achieve satisfactory longitUdinal stability as the wing sweep was varied. Late in 1958 a research breakthrough at Langley provided the technology for designing a variable-sweep wing having satisfactory stability through a wide sweep angle range without the necessity for fore and aft translation of the wing. In this same period there evolved within the military services an urgent requirement for a versatile fighter-bomber that could fly efficiently at subsonic and supersonic speeds at high altitude and "on the deck". The application of variable sweep to this mission requirement then became obvious.

Selective sweeps in the homoploid hybrid species Helianthus deserticola: evolution in concert across populations and across origins

PubMed Central

GROSS, BRIANA L.; TURNER, KATHRYN G.; RIESEBERG, LOREN H.

2008-01-01

The evolution of different populations within a species in response to selective pressures can potentially happen in three different ways. It can occur in parallel, where similar changes occur independently in each population in response to selection; in concert, where the spread of an adaptive mutation across a species’ range results in a single allele fixing in each population; or populations can diverge in response to local selective pressures. We explored these possibilities in populations of the homoploid hybrid species Helianthus deserticola relative to its parental species Helianthus annuus and Helianthus petiolaris using an analysis of variation in 96 expressed sequence tag-based microsatellites. A total of nine loci showed evidence consistent with recent selection at either the species or population level, although two of these genes were discarded because the apparent sweep did not occur relative to the parent from which the locus was derived. Between one and five loci showed a putative sweep across the entire species range with the same microsatellite allele fixed in each population. This pattern is consistent with evolution in concert despite geographical isolation and potential independent origins of the populations. Only one population of H. deserticola showed candidate sweeps that were unique compared to the rest of the species, and this population has also potentially experienced recent admixture with the parental species. PMID:18092993

Study of the tritium behavior on the surface of Li 2O by means of work function measurement

NASA Astrophysics Data System (ADS)

Yokota, Toshihiko; Suzuki, Atsushi; Yamaguchi, Kenji; Terai, Takayuki; Yamawaki, Michio

2000-12-01

In the present study, the work function change of Li 2O due to change of oxygen potential of sweep gas was investigated by measuring the contact potential difference (CPD) between Li 2O and Pt electrodes with a so-called `high temperature Kelvin probe'. The CPD change for Li 2O was generally insensitive to the oxygen partial pressure in the sweep gas. A similar insensitivity was also observed for LiAlO 2. Although the CPD change of Li 2O was about 200 mV when the oxygen partial pressure was changed by as much as 15 orders of magnitude, such was not the case for LiAlO 2. By comparing with the results obtained for other Li-bearing ceramics, it was estimated to be caused by the adsorption/desorption processes of water vapor contained in the sweep gas.

Sweep-net sampling acorns in forested wetlands

Treesearch

Mitch D. Weegman; Richard M. Kaminski; Guiming Wang; Michael L. Schummer; Andrew W. Ezell; Theodor D. Leininger

2010-01-01

We are unaware of any previous studies to evaluate using a sweep net to estimate abundance of red oak acorns (Quercus spp.) after they fall from tree crowns, sink to the ground in flooded bottomlands (i.e., sound acorns), and become potential food for animals or propagules for seedlings. We placed known numbers of white-painted red oak acorns of 3 size classes and used...

Objective quantification of the tinnitus decompensation by synchronization measures of auditory evoked single sweeps.

PubMed

Strauss, Daniel J; Delb, Wolfgang; D'Amelio, Roberto; Low, Yin Fen; Falkai, Peter

2008-02-01

Large-scale neural correlates of the tinnitus decompensation might be used for an objective evaluation of therapies and neurofeedback based therapeutic approaches. In this study, we try to identify large-scale neural correlates of the tinnitus decompensation using wavelet phase stability criteria of single sweep sequences of late auditory evoked potentials as synchronization stability measure. The extracted measure provided an objective quantification of the tinnitus decompensation and allowed for a reliable discrimination between a group of compensated and decompensated tinnitus patients. We provide an interpretation for our results by a neural model of top-down projections based on the Jastreboff tinnitus model combined with the adaptive resonance theory which has not been applied to model tinnitus so far. Using this model, our stability measure of evoked potentials can be linked to the focus of attention on the tinnitus signal. It is concluded that the wavelet phase stability of late auditory evoked potential single sweeps might be used as objective tinnitus decompensation measure and can be interpreted in the framework of the Jastreboff tinnitus model and adaptive resonance theory.

Detection of selective sweeps in cattle using genome-wide SNP data

PubMed Central

2013-01-01

Background The domestication and subsequent selection by humans to create breeds and biological types of cattle undoubtedly altered the patterning of variation within their genomes. Strong selection to fix advantageous large-effect mutations underlying domesticability, breed characteristics or productivity created selective sweeps in which variation was lost in the chromosomal region flanking the selected allele. Selective sweeps have now been identified in the genomes of many animal species including humans, dogs, horses, and chickens. Here, we attempt to identify and characterise regions of the bovine genome that have been subjected to selective sweeps. Results Two datasets were used for the discovery and validation of selective sweeps via the fixation of alleles at a series of contiguous SNP loci. BovineSNP50 data were used to identify 28 putative sweep regions among 14 diverse cattle breeds. Affymetrix BOS 1 prescreening assay data for five breeds were used to identify 85 regions and validate 5 regions identified using the BovineSNP50 data. Many genes are located within these regions and the lack of sequence data for the analysed breeds precludes the nomination of selected genes or variants and limits the prediction of the selected phenotypes. However, phenotypes that we predict to have historically been under strong selection include horned-polled, coat colour, stature, ear morphology, and behaviour. Conclusions The bias towards common SNPs in the design of the BovineSNP50 assay led to the identification of recent selective sweeps associated with breed formation and common to only a small number of breeds rather than ancient events associated with domestication which could potentially be common to all European taurines. The limited SNP density, or marker resolution, of the BovineSNP50 assay significantly impacted the rate of false discovery of selective sweeps, however, we found sweeps in common between breeds which were confirmed using an ultra-high-density assay scored in a small number of animals from a subset of the breeds. No sweep regions were shared between indicine and taurine breeds reflecting their divergent selection histories and the very different environmental habitats to which these sub-species have adapted. PMID:23758707

Electrochemistry and Spectroelectrochemistry of 1,8-Naphthalene and 1,8- Anthracene-Linked Cofacial Binuclear Metallophthalocynanines. New Mixed Valence Metallopthalocyanines

DTIC Science & Technology

1990-05-10

slope of a plot of peak current vs. sweep rate to the charge should be equal to nF/4RT, where n is the number of electrons per adsorbed species and...overlapping waves. b) Values ofAEp : (Ep. - Epe) are given at a potential sweep rate of 50 mV/s. c) data fom ref.8g. d) Potentials are approximate because...cyclic voltametry at 200, 100, 50 and 20 mV/s, Average data being E : (Eps + Epc)/2 are reported. Data in parenthesis are estimated from overlapping

Spectroscopic Determination of the AC Voltammetric Response.

DTIC Science & Technology

1984-01-06

characterization of electrode processes. More recently, with the advent of linear sweep cyclic AC voltanmetry(12’ 13), it has been shown that AC methods...implemented with the same instrumentation ( 7 ) as previously used in MSRS and retains both the qualitative and quantitative utility of linear sweep ...voltammetric response (eg. peak width at balf-height, peak separation and cross-over potential in cyclic AC voltametry ) apply equally well to the SACRS

Selective sweeps of mitochondrial DNA can drive the evolution of uniparental inheritance.

PubMed

Christie, Joshua R; Beekman, Madeleine

2017-08-01

Although the uniparental (or maternal) inheritance of mitochondrial DNA (mtDNA) is widespread, the reasons for its evolution remain unclear. Two main hypotheses have been proposed: selection against individuals containing different mtDNAs (heteroplasmy) and selection against "selfish" mtDNA mutations. Recently, uniparental inheritance was shown to promote adaptive evolution in mtDNA, potentially providing a third hypothesis for its evolution. Here, we explore this hypothesis theoretically and ask if the accumulation of beneficial mutations provides a sufficient fitness advantage for uniparental inheritance to invade a population in which mtDNA is inherited biparentally. In a deterministic model, uniparental inheritance increases in frequency but cannot replace biparental inheritance if only a single beneficial mtDNA mutation sweeps through the population. When we allow successive selective sweeps of mtDNA, however, uniparental inheritance can replace biparental inheritance. Using a stochastic model, we show that a combination of selection and drift facilitates the fixation of uniparental inheritance (compared to a neutral trait) when there is only a single selective mtDNA sweep. When we consider multiple mtDNA sweeps in a stochastic model, uniparental inheritance becomes even more likely to replace biparental inheritance. Our findings thus suggest that selective sweeps of beneficial mtDNA haplotypes can drive the evolution of uniparental inheritance. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Investigation of Spiral and Sweeping Holes

NASA Technical Reports Server (NTRS)

Thurman, Douglas; Poinsatte, Philip; Ameri, Ali; Culley, Dennis; Raghu, Surya; Shyam, Vikram

2015-01-01

Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing rations of 1.0, 1.5, 2.0, and 2.5 at a density ration of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.

Variation sweep rate cyclic voltammetry on the capacitance electrode activated carbon/PVDF with polymer electrolyte

NASA Astrophysics Data System (ADS)

Rohmawati, L.; Setyarsih, W.; Nurjannah, T.

2018-03-01

Sweep rate of the process voltammetry cyclic characterization is very influential towards the electrode capacitance value, especially on activated carbon electrodes/PVDF. A simple method of this research by use a mixing for electrode activated carbon/10 wt. % PVDF and the separator is made of a polymer electrolyte (PVA/H3PO4) by a sol gel method. The prototype supercapacitor is made in the form of a sandwich with a separator placed between two electrodes. Electrodes and separators are arranged in layers at a pressure of 1500 psi, then heated at 50°C for 10 minutes. Next done cyclic voltammetry in a potential range of -1 V to 1 V with a sweep rate of 5 mV/s, 10 mV/s, 20 mV/s, 25 mV/s and 50 mV/s. This results of curves voltammogram is reversible, the most wide curve on the sweep rate of 5 mV/s and most narrow curve on a sweep rate of 50 mV/s. Supercapacitor capacitance values obtained by 86 F/g, 43 F/g, 21 F/g, 16 F/g, and 8 F/g.

The effect of curve sawing two-sided cants from small diameter hardwood sawlogs on lumber and pallet part yields

Treesearch

Peter Hamner; Marshall S. White; Philip A. Araman

2006-01-01

Curve sawing is a primary log breakdown process that incorporates gang-saw technology to allow two-sided cants from logs with sweep to be cut parallel to the log surface or log axis. Since curve-sawn logs with sweep are cut along the grain, the potential for producing high quality straight-grain lumber and cants increases, and strength, stiffness, and dimensional...

Turbulent Reynolds stress and quadrant event activity in wind flow over a coastal foredune

NASA Astrophysics Data System (ADS)

Chapman, Connie A.; Walker, Ian J.; Hesp, Patrick A.; Bauer, Bernard O.; Davidson-Arnott, Robin G. D.

2012-05-01

Recent research on quasi-instantaneous turbulent kinematic Reynolds stresses (RS, - u'w') and decomposed quadrant event activity (e.g., ejections and sweeps) over dunes in fluvial settings and in wind tunnels has shown that turbulent stresses at the toe of a dune often exceed time-averaged, streamwise shear stress (ρ u * 2) estimates. It is believed that semi-coherent turbulent structures are conveyed toward the bed along concave streamlines in this region and that impact of these structures cause fluctuations in local surface stresses that assist in grain entrainment. This has been hypothesized to explain how sand is supplied to the windward slope through a region of flow stagnation. Toward the crest, surface stress increases and becomes dominated by streamwise accelerations resulting from streamline compression and convexity that suppress vertical motions. High-frequency (32 Hz) measurements of turbulent wind flow from 3-D ultrasonic anemometers are analyzed for oblique onshore flow over a vegetated coastal foredune in Prince Edward Island, Canada. Reynolds stress and quadrant activity distributions varied with height (0.60 m and 1.66 m) and location over the dune. In general, quadrant 2 ejection (u' < 0, w' > 0) and quadrant 4 sweep activity (u' > 0, w' < 0) dominated momentum transfer and RS generation over quadrant 1 outward interaction (u' > 0, w' > 0) and quadrant 3 inward interaction (u' < 0, w' < 0) activity. On the lower stoss slope, significant ejection and sweep event activity was most frequent (85 to 92%, ejections plus sweeps), whereas, at the upper crest, significant ejection and sweep activity became less frequent while significant outward and inward interactions increased in frequency (25 to 36%). An 'exuberance effect' (i.e., changing shape of quadrant frequency distribution skewed toward ejection and sweep activity) is observed whereby streamline compression and convexity effects inhibit vertical fluctuations in flow and, thus, reduce the frequency of ejections and sweep activity toward the crest. In separated flow in the lee of the crest, quadrant distributions were more symmetrical as a result of more mixed, multi-directional flow. These trends in turbulent event distributions and Reynolds stress have implications for sediment transport dynamics across the dune and may help to explain sand transport potential and dune maintenance. For example, areas with a high frequency of ejection and sweep activity may have higher rates of sediment entrainment and transport, whereas areas with lower ejection and sweep activity and an increase in outward and inward interactions, which contribute negatively to Reynolds stress generation, may experience a greater potential for deposition. Further research on associations between quadrant event activity and coincident sand transport is required to confirm this hypothesis and the resultant significance of the flow exuberance effect in aeolian dune morphodynamics.

Portable probe to measure sensitization of stainless steel

DOEpatents

Park, Jang Y.

1979-01-01

An electrochemical cell for making field measurements of metals such as stainless steel comprises a cylinder containing a reservoir of an electrolyte, a reference electrode, a capillary tube connecting the electrolyte to the surface of the metal to be measured and another electrode in electrical contact with the electrolyte. External connections from the reference electrode, the other electrode, and the sample to a measuring device provide means for maintaining the potential of the electrolyte while sweeping the potential difference between the electrolyte and the metal. Such a sweep enables the determination of a current-voltage characteristic that is a measure of sensitization in the metal.

Evaluation of a bespoke training to increase uptake by midwifery teams of NICE Guidance for membrane sweeping to reduce induction of labour: a stepped wedge cluster randomised design.

PubMed

Kenyon, Sara; Dann, Sophie; Hope, Lucy; Clarke, Paula; Hogan, Amanda; Jenkinson, David; Hemming, Karla

2017-07-27

National guidance recommends pregnant women are offered membrane sweeping at term to reduce induction of labour. Local audit suggested this was not being undertaken routinely across two maternity units in the West Midlands, UK between March and November 2012. Bespoke training session for midwifery teams (nine community and one antenatal clinic) was developed to address identified barriers to encourage offer of membrane sweeping, together with an information leaflet for women and appointment of a champion within each team. The timing of training session on membrane sweeping to ten midwifery teams was randomly allocated using a stepped wedge cluster randomised design. All women who gave birth in the Trusts after 39 + 3/40 weeks gestation within the study time period were eligible. Relevant anonymised data were extracted from maternity notes for three months before and after training. Data were analysed using a generalised linear mixed model, allowing for clustering and adjusting for temporal effects. Primary outcomes were number of women offered and accepting membrane sweeping and average number of sweeps per woman. Sub-group comparisons were undertaken for adherence to Trust guidance and potential influence of pre-specified maternal characteristics. Data included whether sweeping was offered but declined and no record of membrane sweeping. Training was given to all teams as planned. Analyses included data from 2787 of the 2864 (97%) eligible low-risk women over 39 + 4 weeks pregnant. Characteristics of the women were similar before and after training. No evidence of difference in proportion of women being offered and accepting membrane sweeping (44.4% before training versus 46.8% after training (adjusted relative risk [aRR] = 0.90, 95% confidence interval [CI] = 0.71-1.13), nor in average number of sweeps per woman (0.603 versus 0.627, aRR = 0.83, 95% CI = 0.67-1.01). No differences in any secondary outcomes nor influence of maternal characteristics were demonstrated. The midwives evaluated training positively. This stepped wedge cluster trial enabled randomised evaluation within a natural roll-out and demonstrates the importance of robust evaluation in circumstances in which it is rarely undertaken. While the midwives evaluated the training positively, it did not appear to change practice. ISRCTN14300475 . Registered on 23 August 2016.

In vitro assessment of fiber sweeping speed during Q-switched 532-nm laser tissue ablation

NASA Astrophysics Data System (ADS)

Rajabhandharaks, Danop; Kang, Hyun Wook; Ko, Woo Jin; Stinson, Douglas; Choi, Benjamin

2011-03-01

Photoselective vaporization of the prostate (PVP) is considered a minimally invasive procedure to treat benign prostatic hyperplasia (BPH). During the PVP, the prostate gland is irradiated by the 532-nm laser and the fiber is swept and dragged along the urethra. In this study the speed of sweeping fiber during the PVP is being investigated. In vitro porcine kidney model was used (N=100) throughout the experiment. A Q-switched 532-nm laser, equipped with sidefiring 750-Um fiber, was employed and set to power levels of 120 and 180 W. The speed of fiber sweeping was the only variable in this study and varied at 0 (i.e. no sweeping), 0.5, 1.0, 1.5, and 2.0 sweep/s. Ablation rate, depth, and coagulation thickness were quantified. Based on the current settings, ablation rate decreased as sweeping speed increased and was maximized between 0 to 1.0 sweep/s for 120-W power level and between 0 to 0.5 sweep/s for 180-W power level. Ablation rate at 180 W was higher than that at 120 W, regardless of sweeping speed. Ablation depth at both 120 and 180 W was maximized at 0 sweep/s and decreased 35% at 0.5 sweep/s. The overall coagulation thickness was less than 1.5 mm and comparable from 0 to 1.5 sweep/s (0.8~0.9 mm) and increased at 2.0 sweep/s (~1.1 mm). This study demonstrated that tissue ablation performance was contingent upon sweeping speed and maximized at slow sweeping speed due to longer laser-tissue interaction time and larger area coverage by the 532-nm light.

High Temperature Electrolysis using Electrode-Supported Cells

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

J. E. O'Brien; C. M. Stoots

2010-07-01

An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. The cells currently under study were developed primarily for the fuel cell mode of operation. Results presented in this paper were obtained from single cells, with an active area of 16 cm2 per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes (~10 µm thick), nickel-YSZ steam/hydrogen electrodes (~1400 µm thick), and manganite (LSM) air-side electrodes (~90 µm thick). The purpose of the present study was to document and compare the performance and degradation ratesmore » of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of DC potential sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-duration testing, first in the fuel cell mode, then in the electrolysis mode over more than 500 hours of operation. Results indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of the single-cell test apparatus developed specifically for these experiments.« less

Reverse spontaneous laser line sweeping in ytterbium fiber laser

NASA Astrophysics Data System (ADS)

Navratil, P.; Peterka, P.; Honzatko, P.; Kubecek, V.

2017-03-01

Self-induced laser line sweeping of various regimes of sweep direction is reported for an experimental ytterbium fiber laser. The regimes involve sweeping from shorter to longer wavelengths (1076~\\text{nm}\\to 1083 nm)—so-called normal self-sweeping; from longer to shorter wavelengths (1079~\\text{nm}\\to 1073 nm)—so-called reverse self-sweeping; and a mixed regime in which a precarious balance of the normal and reverse sweeping exists and the sweep direction can change between consecutive sweeps. The regimes of sweeping were selected by changing the pump wavelength only. A detailed explanation of this sweep direction dynamics is presented based on a semi-empirical model. This model also provides a way to predict the sweep direction of fiber lasers based on other rare-earth-doped laser media.

Electrical behaviour of fully solution processed HfO2 (MOS) in presence of different light illumination

NASA Astrophysics Data System (ADS)

Mondal, Sandip

2018-04-01

This experiment demonstrates the electrical behaviors of fully solution processed HfO2(MOS) in presence of different optical illumination. The capacitance voltage measurement was performed at frequency of 100 kHz with a DC gate sweep voltage of ±5V (with additional AC voltage of 100mV) in presence of deep UV (wavelength of 365nm with power of 25W) as well as white light (20W). It is found that there is a large shift in flatband voltage of 120mV due presence of white light during the CV measurement. However there is negligible change in flatband voltage (30mV) has been observed due to illumination of deep UV light.

Magnetic-field-induced phase transition and sliding motion of charge-density waves in {eta}-Mo{sub 4}O{sub 11} crystals

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

Sasaki, M.; Hara, Y.; Inoue, M.

1997-02-01

Transverse magnetoresistance and Hall effect of the charge-density-wave (CDW) material {eta}-Mo{sub 4}O{sub 11} have been measured at 4.2 K (second CDW state) by dc and ac methods over the frequency range 50{endash}500 kHz in pulsed magnetic fields up to 40 T. These quantities are both reversible and frequency independent for a low-field sweep up to near 10 T (=H{sub c}), beyond which an appreciable frequency-dependent hysteresis effect appears. The Cole-Cole plots of the real versus imaginary parts of the magnetoresistance at high magnetic fields show a monodispersion. The magnetic-field dependence of the real part of the ac Hall resistivity showsmore » interesting behaviors, peaking near H{sub c}, followed by a decrease with H and a leveling off at high fields, while the imaginary components are very small and less frequency dependent. Using a multicarrier model consisting of the remaining and nested electron and hole bands, we have performed computer simulations for these dc and ac magnetotransport quantities, in satisfactory agreement with the observations. We have taken into account (1) the Zeeman effect for two types of the remaining hole and electron bands, (2) the CDW-gap narrowing of the nested electron and hole bands, (3) magnetic-field-induced CDW-to-normal phase transition in part of these nested bands, and (4) the magnetic-field-induced {open_quotes}CDW oscillation{close_quotes} around some mean position of the CDW condensates (or thermal excitation of the CDW phasons over a pinning potential), according to the existing CDW model. {copyright} {ital 1997} {ital The American Physical Society}« less

Electrical Field Dependence of Protein Conformation and Channel Function in Lipid Membranes of Different Compositions

DTIC Science & Technology

1989-07-01

surface because of the previous potential sweeps ). c- Cyclic voltamograms after different exposure times of the Hg drop electrode to a solution of lpg/ml...Cd + and 10-M NaCl. b - Cyclic voltamograms under similar conditions. Exposure time indicated, sweep rate O.2V/sec. specific capacitance < 4pf/cm 2...alamethicin. Cyclic voltametry shows (Fig. 3b) that it is the reduction current depending on the transport of TI+ ions across the monolayer to the electrode

[Relation between frequency modulation direction selectivity and forward masking of inferior collicular neurons: a study on in vivo intracellular recording in mice].

PubMed

Fu, Zi-Ying; Zeng, Hong; Tang, Jia; Li, Jie; Li, Juan; Chen, Qi-Cai

2013-06-25

It has been reported that the frequency modulation (FM) or FM direction sensitivity and forward masking of central auditory neurons are related with the neural inhibition, but there are some arguments, because no direct evidence of inhibitory synaptic input was obtained in previous studies using extracellular recording. In the present study, we studied the relation between FM direction sensitivity and forward masking of the inferior collicular (IC) neurons using in vivo intracellular recordings in 20 Mus musculus Km mice. Thirty seven with complete data among 93 neurons were analyzed and discussed. There was an inhibitory area which consisted of inhibitory postsynaptic potentials (IPSP) at high frequency side of frequency tuning of up-sweep FM (FMU) sensitive neurons (n = 12) and at low frequency side of frequency tuning of down-sweep FM (FMD) selective neurons (n = 8), while there was no any inhibitory area at both sides of frequency tuning of non-FM sweep direction (FMN) sensitive neurons (n = 17). Therefore, these results show that the inhibitory area at low or high frequency side of frequency tuning is one of the mechanisms for forming FM sweep direction sensitivity of IC neurons. By comparison of forward masking produced by FMU and FMD sound stimuli in FMU, FMD and FMN neurons, the selective FM sounds could produce stronger forward masking than the non-selective in FMU and FMD neurons, while there was no forward masking difference between FMU and FMD stimuli in the FMN neurons. We suggest that the post-action potential IPSP is a potential mechanism for producing stronger forward masking in FMU and FMD neurons.

[Electrophysiological markers of middle cerebral artery blood flow velocity in healthy subjects].

PubMed

Fokin, V F; Ponomareva, N V; Kuntsevich, G I

2013-01-01

to determine electrophysiological markers of middle cerebral artery blood flow velocity (BFV). transcranial Doppler registration of middle cerebral artery BFV and direct current (DC) potentials recording from surface of head were performed in 30 healthy volunteers. Analysis of correlation between the BFV and DC potentials was used. significant correlation between BFV and DC potential characteristics was observed. The highest correlation was found between BFV in middle cerebral artery and the difference of DC potentials between central and temporal areas of head (r = 0,55; p = 0,003). These areas coincide with the location of middle cerebral artery and the correlation observed may be connected with streaming potential generated by the blood flow in middle cerebral artery. If electrode placement did not coincide with blood current, DC potentials and BFV were not correlated. it is assumed that electrical field created BFV in middle cerebral artery may contribute to the generation of DC potentials registered from the head.

A comparison of three macroinvertebrate sampling devices for use in conducting rapid-assessment procedures of Delmarva Peninsula wetlands

USGS Publications Warehouse

Lowe, Terrence (Peter); Tebbs, Kerry; Sparling, Donald W.

2016-01-01

Three types of macroinvertebrate collecting devices, Gerking box traps, D-shaped sweep nets, and activity traps, have commonly been used to sample macroinvertebrates when conducting rapid biological assessments of North American wetlands. We compared collections of macroinvertebrates identified to the family level made with these devices in 6 constructed and 2 natural wetlands on the Delmarva Peninsula of Maryland. We also assessed their potential efficacy in comparisons among wetlands using several proportional and richness attributes. Differences in median diversity among samples from the 3 devices were significant; the sweep-net samples had the greatest diversity and the activity-trap samples had the least diversity. Differences in median abundance were not significant between the Gerking box-trap samples and sweep-net samples, but median abundance among activity-trap samples was significantly lower than among samples of the other 2 devices. Within samples, the proportions of median diversity composed of major class and order groupings were similar among the 3 devices. However the proportions of median abundance composed of the major class and order groupings within activity-trap samples were not similar to those of the other 2 devices. There was a slight but significant increase in the total number of families captured when we combined activity-trap samples with Gerking box-trap samples or with sweep-net samples, and the per-sample median numbers of families of the combined activity-trap and sweep-net samples was significantly higher than that of the combined activity-trap and Gerking box-trap samples. We detected significant differences among wetlands for 4 macroinvertebrate attributes with the Gerking box-trap data, 6 attributes with sweep-net data, and 5 attributes with the activity-trap data. A small, but significant increase in the number of attributes showing differences among wetlands occurred when we combined activity-trap samples with those of the Gerking boxtrap or sweep net.

Application of the WEPS and SWEEP models to non-agricultural disturbed lands.

PubMed

Tatarko, J; van Donk, S J; Ascough, J C; Walker, D G

2016-12-01

Wind erosion not only affects agricultural productivity but also soil, air, and water quality. Dust and specifically particulate matter ≤10 μm (PM-10) has adverse effects on respiratory health and also reduces visibility along roadways, resulting in auto accidents. The Wind Erosion Prediction System (WEPS) was developed by the USDA-Agricultural Research Service to simulate wind erosion and provide for conservation planning on cultivated agricultural lands. A companion product, known as the Single-Event Wind Erosion Evaluation Program (SWEEP), has also been developed which consists of the stand-alone WEPS erosion submodel combined with a graphical interface to simulate soil loss from single (i.e., daily) wind storm events. In addition to agricultural lands, wind driven dust emissions also occur from other anthropogenic sources such as construction sites, mined and reclaimed areas, landfills, and other disturbed lands. Although developed for agricultural fields, WEPS and SWEEP are useful tools for simulating erosion by wind for non-agricultural lands where typical agricultural practices are not employed. On disturbed lands, WEPS can be applied for simulating long-term (i.e., multi-year) erosion control strategies. SWEEP on the other hand was developed specifically for disturbed lands and can simulate potential soil loss for site- and date-specific planned surface conditions and control practices. This paper presents novel applications of WEPS and SWEEP for developing erosion control strategies on non-agricultural disturbed lands. Erosion control planning with WEPS and SWEEP using water and other dust suppressants, wind barriers, straw mulch, re-vegetation, and other management practices is demonstrated herein through the use of comparative simulation scenarios. The scenarios confirm the efficacy of the WEPS and SWEEP models as valuable tools for supporting the design of erosion control plans for disturbed lands that are not only cost-effective but also incorporate a science-based approach to risk assessment.

Space Flight Plasma Data Analysis

NASA Technical Reports Server (NTRS)

Wright, Kenneth H.; Minow, Joseph I.

2009-01-01

This slide presentation reviews a method to analyze the plasma data that is reported on board the International Space station (ISS). The Floating Potential Measurement Unit (FPMU), the role of which is to obtain floating potential and ionosphere plasma measurements for validation of the ISS charging model, assess photo voltaic array variability and interpreting IRI predictions, is composed of four probes: Floating Potential Probe (FPP), Wide-sweep Langmuir Probe (WLP), Narrow-sweep Langmuir Probe (NLP) and the Plasma Impedance Probe (PIP). This gives redundant measurements of each parameter. There are also many 'boxes' that the data must pass through before being captured by the ground station, which leads to telemetry noise. Methods of analysis for the various signals from the different sets are reviewed. There is also a brief discussion of LP analysis of Low Earth Orbit plasma simulation source.

Toward Cooling Uniformity: Investigation of Spiral, Sweeping Holes, and Unconventional Cooling Paradigms

NASA Technical Reports Server (NTRS)

Shyam, Vikram; Thurman, Douglas R.; Poinsatte, Philip E.; Ameri, Ali A.; Culley, Dennis E.

2018-01-01

Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. Ways to quantify the efficacy of novel cooling holes that are asymmetric, not uniformly spaced or that show variation from hole to hole are presented. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and square holes. A patent-pending spiral hole design showed the highest potential of the nondiffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing ratios of 1.0, 1.5, 2.0, and 2.5 at a density ratio of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS. A section on ideas for future work is included that addresses issues of quantifying cooling uniformity and provides some ideas for changing the way we think about cooling such as changing the direction of cooling or coupling acoustic devices to cooling holes to regulate frequency.

The Influence of Uncompensated Solution Resistance on the Determination and Standard Electrochemical Rate Constants Using Cyclic Voltammetry, and Some Comparisons with AC Voltammetry.

DTIC Science & Technology

1987-09-25

rate constants, k2r using cyclic voltametry . The res tss are expressed in terms of systematic deviations oP sapparent measured" rate constants, k~b(app...concentration was taken to be lum unless otherwise noted. The voltammetric sweep rate was set at 20 V sŕ unless specified otherwise. The general procedure...peaks for the negative- and positive-going potential sweeps have opposite signs, the measured cathodic-anodic peak separation, AEp, will clearly be

A Compact Two-Stage 120 W GaN High Power Amplifier for SweepSAR Radar Systems

NASA Technical Reports Server (NTRS)

Thrivikraman, Tushar; Horst, Stephen; Price, Douglas; Hoffman, James; Veilleux, Louise

2014-01-01

This work presents the design and measured results of a fully integrated switched power two-stage GaN HEMT high-power amplifier (HPA) achieving 60% power-added efficiency at over 120Woutput power. This high-efficiency GaN HEMT HPA is an enabling technology for L-band SweepSAR interferometric instruments that enable frequent repeat intervals and high-resolution imagery. The L-band HPA was designed using space-qualified state-of-the-art GaN HEMT technology. The amplifier exhibits over 34 dB of power gain at 51 dBm of output power across an 80 MHz bandwidth. The HPA is divided into two stages, an 8 W driver stage and 120 W output stage. The amplifier is designed for pulsed operation, with a high-speed DC drain switch operating at the pulsed-repetition interval and settles within 200 ns. In addition to the electrical design, a thermally optimized package was designed, that allows for direct thermal radiation to maintain low-junction temperatures for the GaN parts maximizing long-term reliability. Lastly, real radar waveforms are characterized and analysis of amplitude and phase stability over temperature demonstrate ultra-stable operation over temperature using integrated bias compensation circuitry allowing less than 0.2 dB amplitude variation and 2 deg phase variation over a 70 C range.

Toward smart Nebulization: Engineering acoustic airflow to penetrate maxillary sinuses in chronic rhinosinusitis.

PubMed

Moghadam, Shima Jowhari; Navarro, Laurent; Leclerc, Lara; Hodin, Sophie; Pourchez, Jérémie

2018-07-30

Treating chronic rhinosinusitis (CRS) by nebulization requires an airflow capable to deliver medication to deep target sites beyond the nasal valve. Fixed frequency acoustic airflow technology is currently available, mainly as post-surgical therapy, but still have not been able to realize the full potential of direct nose to paranasal sinuses delivery. Reported herein are the application of frequency sweep acoustic airflow and the optimization of its frequency range, sweep cycle duration and intensity. The resonant frequencies of the model's maxillary sinuses can be estimated using the Helmholtz resonator theory. Results indicated a resonant frequency of 479 Hz for the right maxillary sinus and one of 849 Hz for the left maxillary sinus. The highest intrasinus deposition within the experiments are from sweep cycle duration of 1 s, intensity of 80 dB, and frequency range of 100-850 Hz. The optimal range of frequency determined from experiments is in good agreement with the corresponding frequency range obtained from the Helmholtz resonator theory. Results reveal a significantly enhanced maxillary sinus drug deposition. This technique affords the potential of treating CRS. Copyright © 2018 Elsevier B.V. All rights reserved.

A comparison of spider communities in Bt and non-Bt rice fields.

PubMed

Lee, Sue Yeon; Kim, Seung Tae; Jung, Jong Kook; Lee, Joon-Ho

2014-06-01

To assess the potential adverse effects of a Bt rice line (Japonica rice cultivar, Nakdong) expressing a synthetic cry1Ac1 gene, C7-1-9-1-B, which was highly active against all larval stages of Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Crambidae), we investigated the community structure of spiders in Bt and non-Bt rice fields during the rice-growing season in 2007 and 2008 in Chungcheongnam-do, Korea. Spiders were surveyed with a sweep net and suction device. Suction sampling captured more spiders, measured in terms of species level and abundance, than sweeping. Araneidae and Thomisidae were captured more by sweeping, and certain species were captured only by sweeping. These findings show that both suction and sweep sampling methods should be used because these methods are most likely complementary. In total, 29 species in 23 genera and nine families were identified from the 4,937 spiders collected, and both Bt and non-Bt rice fields showed a typical Korean spider assemblage. The temporal patterns of spider species richness and spider abundance were very similar between Bt and non-Bt rice, although significant differences in species richness were observed on a few occasions. Overall, spider community structure, including diversity, the dominant species, and abundance did not differ between Bt and non-Bt rice. The results of the study indicated that the transgenic Cry1Ac rice lines tested in this study had no adverse effects on the spider community structure of the rice fields.

A Bayesian approach to estimate evoked potentials.

PubMed

Sparacino, Giovanni; Milani, Stefano; Arslan, Edoardo; Cobelli, Claudio

2002-06-01

Several approaches, based on different assumptions and with various degree of theoretical sophistication and implementation complexity, have been developed for improving the measurement of evoked potentials (EP) performed by conventional averaging (CA). In many of these methods, one of the major challenges is the exploitation of a priori knowledge. In this paper, we present a new method where the 2nd-order statistical information on the background EEG and on the unknown EP, necessary for the optimal filtering of each sweep in a Bayesian estimation framework, is, respectively, estimated from pre-stimulus data and obtained through a multiple integration of a white noise process model. The latter model is flexible (i.e. it can be employed for a large class of EP) and simple enough to be easily identifiable from the post-stimulus data thanks to a smoothing criterion. The mean EP is determined as the weighted average of the filtered sweeps, where each weight is inversely proportional to the expected value of the norm of the correspondent filter error, a quantity determinable thanks to the employment of the Bayesian approach. The performance of the new approach is shown on both simulated and real auditory EP. A signal-to-noise ratio enhancement is obtained that can allow the (possibly automatic) identification of peak latencies and amplitudes with less sweeps than those required by CA. For cochlear EP, the method also allows the audiology investigator to gather new and clinically important information. The possibility of handling single-sweep analysis with further development of the method is also addressed.

Alterations in dendritic cell function in aged mice: potential implications for immunotherapy design.

PubMed

Paula, Carine; Motta, Adriana; Schmitz, Carla; Nunes, Claudia P; Souza, Ana Paula; Bonorino, Cristina

2009-02-01

It is known that immune system functions decrease with age, and that adaptive immune responses, especially CD4+ T cell function, seem to be the main affected point in immunity with aging. Dendritic cells (DC) are the major antigen presenting cell (APC), and at least part of the defects observed in adaptive immunity of aged individuals could be due to diminished potential of bone marrow to generate new DC, or defects in DC function. In this study, we investigated if the ability of aged bone marrow (BM) to generate new DC in vitro, as well as aged BM-derived DC responses to lypopolysaccharide (LPS). Because DC are important tools in newly developing anti-tumor therapies, we also studied the ability of aged DC to phagocytose and present antigen from necrotic tumor cells. We found that aged BM generated fewer DC in vitro compared to young BM. While LPS-induced DC maturation is reduced in DC of aged mice, a high TNF-alpha production is observed in aged DC even without LPS stimulation. While phagocytosis of tumor cells is not affected by age, and DC derived from aged BM show a higher TNF-alpha production in response to phagocytosis, presentation of tumor antigens was decreased in aged DC. Because class II upregulation in response to phagocytosis was similar between aged and young DC, this could indicate an age associated processing defect in the exogenous pathway. These findings suggest that age of BM used to generate DC does not impair their phagocytic ability or TNF-alpha production, however leads to a decreased yield in mature DC, reduced response to LPS, and diminished antigen processing/presentation potential. Our results are relevant to optimization DC-based vaccine design for aged populations.

Fabrication and characterization of magnetically tunable metal-semiconductor schottky diode using barium hexaferrite thin film on gold

NASA Astrophysics Data System (ADS)

Kaur, Jotinder; Sharma, Vinay; Sharma, Vipul; Veerakumar, V.; Kuanr, Bijoy K.

2016-05-01

Barium Hexaferrite (BaM) is an extensively studied magnetic material due to its potential device application. In this paper, we study Schottky junction diodes fabricated using gold and BaM and demonstrate the function of a spintronic device. Gold (50 nm)/silicon substrate was used to grow the BaM thin films (100-150 nm) using pulsed laser deposition. I-V characteristics were measured on the Au/BaM structure sweeping the voltage from ±5 volts. The forward and reverse bias current-voltage curves show diode like rectifying characteristics. The threshold voltage decreases while the output current increases with increase in the applied external magnetic field showing that the I-V characteristics of the BaM based Schottky junction diodes can be tuned by external magnetic field. It is also demonstrated that, the fabricated Schottky diode can be used as a half-wave rectifier, which could operate at high frequencies in the range of 1 MHz compared to the regular p-n junction diodes, which rectify below 10 kHz. In addition, it is found that above 1 MHz, Au/BaM diode can work as a rectifier as well as a capacitor filter, making the average (dc) voltage much larger.

Soft Shoulders Ahead: Spurious Signatures of Soft and Partial Selective Sweeps Result from Linked Hard Sweeps

PubMed Central

Schrider, Daniel R.; Mendes, Fábio K.; Hahn, Matthew W.; Kern, Andrew D.

2015-01-01

Characterizing the nature of the adaptive process at the genetic level is a central goal for population genetics. In particular, we know little about the sources of adaptive substitution or about the number of adaptive variants currently segregating in nature. Historically, population geneticists have focused attention on the hard-sweep model of adaptation in which a de novo beneficial mutation arises and rapidly fixes in a population. Recently more attention has been given to soft-sweep models, in which alleles that were previously neutral, or nearly so, drift until such a time as the environment shifts and their selection coefficient changes to become beneficial. It remains an active and difficult problem, however, to tease apart the telltale signatures of hard vs. soft sweeps in genomic polymorphism data. Through extensive simulations of hard- and soft-sweep models, here we show that indeed the two might not be separable through the use of simple summary statistics. In particular, it seems that recombination in regions linked to, but distant from, sites of hard sweeps can create patterns of polymorphism that closely mirror what is expected to be found near soft sweeps. We find that a very similar situation arises when using haplotype-based statistics that are aimed at detecting partial or ongoing selective sweeps, such that it is difficult to distinguish the shoulder of a hard sweep from the center of a partial sweep. While knowing the location of the selected site mitigates this problem slightly, we show that stochasticity in signatures of natural selection will frequently cause the signal to reach its zenith far from this site and that this effect is more severe for soft sweeps; thus inferences of the target as well as the mode of positive selection may be inaccurate. In addition, both the time since a sweep ends and biologically realistic levels of allelic gene conversion lead to errors in the classification and identification of selective sweeps. This general problem of “soft shoulders” underscores the difficulty in differentiating soft and partial sweeps from hard-sweep scenarios in molecular population genomics data. The soft-shoulder effect also implies that the more common hard sweeps have been in recent evolutionary history, the more prevalent spurious signatures of soft or partial sweeps may appear in some genome-wide scans. PMID:25716978

Soft shoulders ahead: spurious signatures of soft and partial selective sweeps result from linked hard sweeps.

PubMed

Schrider, Daniel R; Mendes, Fábio K; Hahn, Matthew W; Kern, Andrew D

2015-05-01

Characterizing the nature of the adaptive process at the genetic level is a central goal for population genetics. In particular, we know little about the sources of adaptive substitution or about the number of adaptive variants currently segregating in nature. Historically, population geneticists have focused attention on the hard-sweep model of adaptation in which a de novo beneficial mutation arises and rapidly fixes in a population. Recently more attention has been given to soft-sweep models, in which alleles that were previously neutral, or nearly so, drift until such a time as the environment shifts and their selection coefficient changes to become beneficial. It remains an active and difficult problem, however, to tease apart the telltale signatures of hard vs. soft sweeps in genomic polymorphism data. Through extensive simulations of hard- and soft-sweep models, here we show that indeed the two might not be separable through the use of simple summary statistics. In particular, it seems that recombination in regions linked to, but distant from, sites of hard sweeps can create patterns of polymorphism that closely mirror what is expected to be found near soft sweeps. We find that a very similar situation arises when using haplotype-based statistics that are aimed at detecting partial or ongoing selective sweeps, such that it is difficult to distinguish the shoulder of a hard sweep from the center of a partial sweep. While knowing the location of the selected site mitigates this problem slightly, we show that stochasticity in signatures of natural selection will frequently cause the signal to reach its zenith far from this site and that this effect is more severe for soft sweeps; thus inferences of the target as well as the mode of positive selection may be inaccurate. In addition, both the time since a sweep ends and biologically realistic levels of allelic gene conversion lead to errors in the classification and identification of selective sweeps. This general problem of "soft shoulders" underscores the difficulty in differentiating soft and partial sweeps from hard-sweep scenarios in molecular population genomics data. The soft-shoulder effect also implies that the more common hard sweeps have been in recent evolutionary history, the more prevalent spurious signatures of soft or partial sweeps may appear in some genome-wide scans. Copyright © 2015 by the Genetics Society of America.

Investigation of the Effect of Blade Sweep on Rotor Vibratory Loads

NASA Technical Reports Server (NTRS)

Tarzanin, F. J., Jr.; Vlaminck, R. R.

1983-01-01

The effect of helicopter rotor blade planform sweep on rotor vibratory hub, blade, and control system loads has been analytically investigated. The importance of sweep angle, sweep initiation radius, flap bending stiffness and torsion bending stiffness is discussed. The mechanism by which sweep influences the vibratory hub loads is investigated.

Potential effects of structural controls and street sweeping on stormwater loads to the lower Charles River, Massachusetts

USGS Publications Warehouse

Zarriello, Phillip J.; Breault, Robert F.; Weiskel, Peter K.

2002-01-01

The water quality of the lower Charles River is periodically impaired by combined sewer overflows (CSOs) and non-CSO stormwater runoff. This study examined the potential non-CSO load reductions of suspended solids, fecal coliform bacteria, total phosphorus, and total lead that could reasonably be achieved by implementation of stormwater best management practices, including both structural controls and systematic street sweeping. Structural controls were grouped by major physical or chemical process; these included infiltration-filtration (physical separation), biofiltration-bioretention (biological mechanisms), or detention-retention (physical settling). For each of these categories, upper and lower quartiles, median, and average removal efficiencies were compiled from three national databases of structural control performance. Removal efficiencies obtained indicated a wide range of performance. Removal was generally greatest for infiltration-filtration controls and suspended solids, and least for biofiltration-bioretention controls and fecal coliform bacteria. Street sweeping has received renewed interest as a water-quality control practice because of reported improvements in sweeper technology and the recognition that opportunities for implementing structural controls are limited in highly urbanized areas. The Stormwater Management Model that was developed by the U.S. Geological Survey for the lower Charles River Watershed was modified to simulate the effects of street sweeping in a single-family land-use basin. Constituent buildup and washoff variable values were calibrated to observed annual and storm-event loads. Once calibrated, the street sweeping model was applied to various permutations of four sweeper efficiencies and six sweeping frequencies that ranged from every day to once every 30 days. Reduction of constituent loads to the lower Charles River by the combined hypothetical practices of structural controls and street sweeping was estimated for a range of removal efficiencies because of their inherent variability and uncertainty. This range of efficiencies, with upper and lower estimates, provides reasonable bounds on the load that could be removed by the practices examined. The upper estimated load reduction from combined street sweeping and structural controls, as a percentage of the total non-CSO load entering the lower Charles River downstream of Watertown Dam, was 44 percent for suspended solids, 34 percent for total lead, 14 percent for total phosphorus, and 17 percent for fecal coliform bacteria. The lower estimated load reduction from combined street sweeping and structural controls from non-CSO sources downstream of Watertown Dam, was 14 percent for suspended solids, 11 percent for total lead, 4.9 percent for total phosphorus, and 7.5 percent for fecal coliform bacteria. Load reductions by these combined management practices can be a small as 1.4 percent for total phosphorus to about 4 percent for the other constituents if the total load above Watertown Dam is added to the load from below the dam. Although the reductions in stormwater loads to the lower Charles River from the control practices examined appear to be minor, these practices would likely provide water-quality benefits to portions of the river during those times that they are most impaired-during and immediately after storms. It should also be recognized that only direct measurements of changes in stormwater loads before and after implementation of control practices can provide definitive evidence of the beneficial effects of these practices on water-quality conditions in the lower Charles River.

Polyhedral sweeping processes with unbounded nonconvex-valued perturbation

NASA Astrophysics Data System (ADS)

Tolstonogov, A. A.

2017-12-01

A polyhedral sweeping process with a multivalued perturbation whose values are nonconvex unbounded sets is studied in a separable Hilbert space. Polyhedral sweeping processes do not satisfy the traditional assumptions used to prove existence theorems for convex sweeping processes. We consider the polyhedral sweeping process as an evolution inclusion with subdifferential operators depending on time. The widely used assumption of Lipschitz continuity for the multivalued perturbation term is replaced by a weaker notion of (ρ - H) Lipschitzness. The existence of solutions is proved for this sweeping process.

Carbon/graphite fiber risk analysis and assessment study: An assessment of the risk to Douglas commercial transport aircraft

NASA Technical Reports Server (NTRS)

Schjelderup, H. C.; Cook, C. Q.; Snyder, E.; Henning, B.; Hosford, J.; Gilles, D. L.; Swanstrom, C. W.

1980-01-01

The potential hazard to electrical and electronic devices should there be a release of free carbon fibers due to an aircraft crash and fire was assessed. Exposure and equipment sensitivity data were compiled for a risk analysis. Results are presented in the following areas: DC-9/DC-10 electrical/electronic component characterization; DC-9 and DC-10 fiber transfer functions; potential for transport aircraft equipment exposure to carbon fibers; and equipment vulnerability assessment. Results reflect only a negligible increase in risk for the DC-9 and DC-10 fleets either now or projected to 1993.

Extreme selective sweeps independently targeted the X chromosomes of the great apes

PubMed Central

Nam, Kiwoong; Munch, Kasper; Hobolth, Asger; Dutheil, Julien Yann; Veeramah, Krishna R.; Woerner, August E.; Hammer, Michael F.; Mailund, Thomas; Schierup, Mikkel Heide

2015-01-01

The unique inheritance pattern of the X chromosome exposes it to natural selection in a way that is different from that of the autosomes, potentially resulting in accelerated evolution. We perform a comparative analysis of X chromosome polymorphism in 10 great ape species, including humans. In most species, we identify striking megabase-wide regions, where nucleotide diversity is less than 20% of the chromosomal average. Such regions are found exclusively on the X chromosome. The regions overlap partially among species, suggesting that the underlying targets are partly shared among species. The regions have higher proportions of singleton SNPs, higher levels of population differentiation, and a higher nonsynonymous-to-synonymous substitution ratio than the rest of the X chromosome. We show that the extent to which diversity is reduced is incompatible with direct selection or the action of background selection and soft selective sweeps alone, and therefore, we suggest that very strong selective sweeps have independently targeted these specific regions in several species. The only genomic feature that we can identify as strongly associated with loss of diversity is the location of testis-expressed ampliconic genes, which also have reduced diversity around them. We hypothesize that these genes may be responsible for selective sweeps in the form of meiotic drive caused by an intragenomic conflict in male meiosis. PMID:25941379

Acoustic performance of dual-electrode electrostatic sound generators based on CVD graphene on polyimide film.

PubMed

Lee, Kyoung-Ryul; Jang, Sung Hwan; Jung, Inhwa

2018-08-10

We investigated the acoustic performance of electrostatic sound-generating devices consisting of bi-layer graphene on polyimide film. The total sound pressure level (SPL) of the sound generated from the devices was measured as a function of source frequency by sweeping, and frequency spectra were measured at 1/3 octave band frequencies. The relationship between various operation conditions and total SPL was determined. In addition, the effects of changing voltage level, adding a DC offset, and using two pairs of electrodes were evaluated. It should be noted that two pairs of electrode operations improved sound generation by about 10 dB over all frequency ranges compared with conventional operation. As for the sound-generating capability, total SPL was 70 dBA at 4 kHz when an AC voltage of 100 V pp was applied with a DC offset of 100 V. Acoustic characteristics differed from other types of graphene-based sound generators, such as graphene thermoacoustic devices and graphene polyvinylidene fluoride devices. The effects of diameter and distance between electrodes were also studied, and we found that diameter greatly influenced the frequency response. We anticipate that the design information provided in this paper, in addition to describing key parameters of electrostatic sound-generating devices, will facilitate the commercial development of electrostatic sound-generating systems.

Genetic targeting of the active transcription factor XBP1s to dendritic cells potentiates vaccine-induced prophylactic and therapeutic antitumor immunity.

PubMed

Tian, Shenghe; Liu, Zuqiang; Donahue, Cara; Falo, Louis D; You, Zhaoyang

2012-02-01

In vivo dendritic cells (DC) targeting is an attractive approach with potential advantages in vaccine efficacy, cost, and availability. Identification of molecular adjuvants to in vivo "modulate " DC to coordinately render improved Th1 and CD8 T cell immunity, and attenuated deleterious Treg effects, is a critical challenge. Here, we report that in vivo genetic targeting of the active transcription factor XBP1s to DC (XBP1s/DC) potentiated vaccine-induced prophylactic and therapeutic antitumor immunity in multiple tumor models. This immunization strategy is based on a genetic vaccine encoding both cytomegalovirus (CMV)-driven vaccine Aghsp70 and DC-specific CD11c-driven XBP1s. The novel targeted vaccine induced durable Th1 and CD8 T cell responses to poorly immunogenic self/tumor antigen (Ag) and attenuated tumor-associated Treg suppressive function. Bone marrow (BM)-derived DC genetically modified to simultaneously overexpress XBP1s and express Aghsp70 upregulated CD40, CD70, CD86, interleukin (IL)-15, IL-15Rα, and CCR7 expression, and increased IL-6, IL-12, and tumor necrosis factor (TNF)-α production in vitro. XBP1s/DC elevated functional DEC205(+)CD8α(+)DC in the draining lymph nodes (DLN). The data suggest a novel role for XBP1s in modulating DC to potentiate tumor vaccine efficacy via overcoming two major obstacles to tumor vaccines (i.e., T cell hyporesponsiveness against poorly immunologic self/tumor Ag and tumor-associated Treg-mediated suppression) and improving DEC205(+)CD8α(+)DC.

Recent selective sweeps in North American Drosophila melanogaster show signatures of soft sweeps.

PubMed

Garud, Nandita R; Messer, Philipp W; Buzbas, Erkan O; Petrov, Dmitri A

2015-02-01

Adaptation from standing genetic variation or recurrent de novo mutation in large populations should commonly generate soft rather than hard selective sweeps. In contrast to a hard selective sweep, in which a single adaptive haplotype rises to high population frequency, in a soft selective sweep multiple adaptive haplotypes sweep through the population simultaneously, producing distinct patterns of genetic variation in the vicinity of the adaptive site. Current statistical methods were expressly designed to detect hard sweeps and most lack power to detect soft sweeps. This is particularly unfortunate for the study of adaptation in species such as Drosophila melanogaster, where all three confirmed cases of recent adaptation resulted in soft selective sweeps and where there is evidence that the effective population size relevant for recent and strong adaptation is large enough to generate soft sweeps even when adaptation requires mutation at a specific single site at a locus. Here, we develop a statistical test based on a measure of haplotype homozygosity (H12) that is capable of detecting both hard and soft sweeps with similar power. We use H12 to identify multiple genomic regions that have undergone recent and strong adaptation in a large population sample of fully sequenced Drosophila melanogaster strains from the Drosophila Genetic Reference Panel (DGRP). Visual inspection of the top 50 candidates reveals that in all cases multiple haplotypes are present at high frequencies, consistent with signatures of soft sweeps. We further develop a second haplotype homozygosity statistic (H2/H1) that, in combination with H12, is capable of differentiating hard from soft sweeps. Surprisingly, we find that the H12 and H2/H1 values for all top 50 peaks are much more easily generated by soft rather than hard sweeps. We discuss the implications of these results for the study of adaptation in Drosophila and in species with large census population sizes.

Production of infectious dromedary camel hepatitis E virus by a reverse genetic system: Potential for zoonotic infection.

PubMed

Li, Tian-Cheng; Zhou, Xianfeng; Yoshizaki, Sayaka; Ami, Yasushi; Suzaki, Yuriko; Nakamura, Tomofumi; Takeda, Naokazu; Wakita, Takaji

2016-12-01

The pathogenicity, epidemiology and replication mechanism of dromedary camel hepatitis E virus (DcHEV), a novel hepatitis E virus (HEV), has been unclear. Here we used a reverse genetic system to produce DcHEV and examined the possibility of zoonotic infection. Capped genomic RNA derived from a synthetic DcHEV cDNA was transfected into human hepatocarcinoma cells PLC/PRF/5. The DcHEV capsid protein and RNA were detected by an enzyme-linked immunosorbent assay (ELISA) or RT-qPCR. A neutralization test for DcHEV was carried out by using antisera against HEV-like particles. DcHEV was used to inoculate two cynomolgus monkeys to examine the potential for cross-species infection. The transfection of PLC/PRF/5 cells with capped DcHEV RNA resulted in the production of infectious DcHEV. The genome sequence analysis demonstrated that both nucleotide and amino acid changes accumulated during the passages in PLC/PRF/5 cells. The cynomolgus monkeys showed serological signs of infection when DcHEV was intravenously inoculated. DcHEV was neutralized by not only anti-DcHEV-LPs antibody, but also anti-genotype 1 (G1), G3 and G4 HEV-LPs antibodies. Moreover, the monkeys immunized with DcHEV escaped the G3 HEV challenge, indicating that the serotype of DcHEV is similar to those of other human HEVs. Infectious DcHEV was produced using a reverse genetic system and propagated in PLC/PRF/5 cells. The antigenicity and immunogenicity of DcHEV are similar to those of G1, G3 and G4 HEV. DcHEV was experimentally transmitted to primates, demonstrating the possibility of a zoonotic infection by DcHEV. Dromedary camel hepatitis E virus (DcHEV) was produced by a reverse genetic system and grows well in PLC/PRF/5 cells. Cynomolgus monkeys experimentally infected with DcHEV indicated serological signs of infection, suggesting that DcHEV has the potential to cause zoonotic HEV infection. Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Expression profiles of genes involved in jasmonic acid biosynthesis and signaling during growth and development of carrot.

PubMed

Wang, Guanglong; Huang, Wei; Li, Mengyao; Xu, Zhisheng; Wang, Feng; Xiong, Aisheng

2016-09-01

Jasmonates (JAs) are recognized as essential regulators in response to environmental stimuli and plant development. Carrot is an Apiaceae vegetable with great value and undergoes significant size changes over the course of plant growth. However, JA accumulation and its potential roles in carrot growth remain unclear. Here, methyl JA (MeJA) levels and expression profiles of JA-related genes were analyzed in carrot roots and leaves at five developmental stages. MeJA levels in the roots and leaves were the highest at the first stage and decreased as carrot growth proceeded. Transcript levels of several JA-related genes (Dc13-LOX1, Dc13-LOX2, DcAOS, DcAOC, DcOPR2, DcOPR3, DcOPCL1, DcJAR1, DcJMT, DcCOI1, DcJAZ1, DcJAZ2, DcMYC2, DcCHIB/PR3, DcLEC, and DcVSP2) were not well correlated with MeJA accumulation during carrot root and leaf development. In addition, some JA-related genes (DcJAR1, DcJMT, DcCOI1, DcMYC2, and DcVSP2) showed differential expression between roots and leaves. These results suggest that JAs may regulate carrot plant growth in stage-dependent and organ-specific manners. Our work provides novel insights into JA accumulation and its potential roles during carrot growth and development. © The Author 2016. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Simultaneous recording of eeg and direct current (DC) potential makes it possible to assess functional and metabolic state of nervous tissue.

PubMed

Murik, S E; Shapkin, A G

2004-08-01

It has been proposed to assess functional and metabolic state of the brain nervous tissue in terms of bioelectrical parameters. Simultaneous recording of the DC potential level and total slow electrical activity of the nervous tissue was performed in the object of study by nonpolarizable Ag/AgCl electrodes with a DC amplifier. The functional and metabolic state of the brain was determined in terms of enhancement or reduction in the total slow electrical activity and positive or negative shifts in the DC potential level.

2D modeling of DC potential structures induced by RF sheaths with transverse currents in front of ICRF antenna

NASA Astrophysics Data System (ADS)

Faudot, E.; Heuraux, S.; Colas, L.

2005-09-01

Understanding DC potential generation in front of ICRF antennas is crucial for long pulse high RF power systems. DC potentials are produced by sheath rectification of these RF potentials. To reach this goal, near RF parallel electric fields have to be computed in 3D and integrated along open magnetic field lines to yield a 2D RF potential map in a transverse plane. DC potentials are produced by sheath rectification of these RF potentials. As RF potentials are spatially inhomogeneous, transverse polarization currents are created, modifying RF and DC maps. Such modifications are quantified on a `test map' having initially a Gaussian shape and assuming that the map remains Gaussian near its summit,the time behavior of the peak can be estimated analytically in presence of polarization current as a function of its width r0 and amplitude φ0 (normalized to a characteristic length for transverse transport and to the local temperature). A `peaking factor' is built from the DC peak potential normalized to φ0, and validated with a 2D fluid code and a 2D PIC code (XOOPIC). In an unexpected way transverse currents can increase this factor. Realistic situations of a Tore Supra antenna are also studied, with self-consistent near fields provided by ICANT code. Basic processes will be detailed and an evaluation of the `peaking factor' for ITER will be presented for a given configuration.

2D modeling of DC potential structures induced by RF sheaths with transverse currents in front of ICRF antenna

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

Faudot, E.; Heuraux, S.; Colas, L.

2005-09-26

Understanding DC potential generation in front of ICRF antennas is crucial for long pulse high RF power systems. DC potentials are produced by sheath rectification of these RF potentials. To reach this goal, near RF parallel electric fields have to be computed in 3D and integrated along open magnetic field lines to yield a 2D RF potential map in a transverse plane. DC potentials are produced by sheath rectification of these RF potentials. As RF potentials are spatially inhomogeneous, transverse polarization currents are created, modifying RF and DC maps. Such modifications are quantified on a 'test map' having initially amore » Gaussian shape and assuming that the map remains Gaussian near its summit,the time behavior of the peak can be estimated analytically in presence of polarization current as a function of its width r0 and amplitude {phi}0 (normalized to a characteristic length for transverse transport and to the local temperature). A 'peaking factor' is built from the DC peak potential normalized to {phi}0, and validated with a 2D fluid code and a 2D PIC code (XOOPIC). In an unexpected way transverse currents can increase this factor. Realistic situations of a Tore Supra antenna are also studied, with self-consistent near fields provided by ICANT code. Basic processes will be detailed and an evaluation of the 'peaking factor' for ITER will be presented for a given configuration.« less

Nonlinear antiferroelectric-like capacitance-voltage curves in ferroelectric BiFeO3 thin films

NASA Astrophysics Data System (ADS)

Jiang, A. Q.; Zhang, D. W.; Tang, T. A.

2013-07-01

The ferroelectric capacitance is usually nonlinear against increasing/decreasing voltage in sweeping time longer than 1 s and achieves a maximum value at around a coercive voltage within each loop. With the improved short-pulse measurements, we estimated the differential capacitance of ferroelectric Au/BiFeO3/LaNiO3/SrTiO3 thin-film capacitors from a nanosecond discharging current induced by a delta voltage after a stressing voltage pulse with widths of 500 ns-50 ms. With the shortening of the voltage sweeping time, we clearly observed two capacitance maxima from each branch of a capacitance-voltage (C-V) loop, reminiscent of an antiferroelectric behavior. After transformation of nanosecond domain switching current transients under pulses into polarization-voltage hysteresis loops, we further measured time dependent polarization retention as well as imprint in the range of 100 ns-1 s. Both positive and negative polarizations decay exponentially at characteristic times of 2.25 and 198 μs, suggesting the coexistence of preferred domains pointing to top and bottom electrodes in most epitaxial films. This exponential time dependence is similar to the dielectric degradation under a dc voltage, and the polarization retention can be improved through long-time opposite voltage stressing. With this improvement, the additional antiferroelectric-like dielectric maximum within each branch of a C-V loop disappears. This experiment provides the strong evidence of the effect of time-dependent charge injection on polarization retention and dielectric degradation.

Real Time Computer Control of Neutral Beam Energy and Current During a DIII-D Tokamak Shot

NASA Astrophysics Data System (ADS)

Pawley, C. J.; Pace, D. C.; Rauch, J. M.; Scoville, J. T.

2017-10-01

A new control system has been implemented on DIII-D neutral beams which has been used during the 2016 and 2017 experimental campaign to directly change the beam acceleration voltage (V) and beam current (I) by the Plasma Control System (PCS) during a shot. Small changes in the beam voltage of 1-2 kV can be made in 1 msec or larger changes of up to 20kV in 0.5 seconds. The beam current can be modified by as much as +/-20% at a fixed beam voltage. Since both can be independently and simultaneously changed it is possible to change beam power (IV) at fixed voltage, keep constant power while sweeping beam voltage, or to maintain minimum beam divergence during a beam voltage sweep by changing I simultaneously to keep a constant beam perveance. The limitations of the variability will be presented with required changes in equipment to extend either the speed or range of the controls. Some of the effects on fast ion plasma instabilities or other plasma mode changes made possible by this control will also be presented (see also D.C. Pace, this conference). Design and changes to the control system was performed under General Atomics Internal Research and Development support, while plasma experiments on DIII-D were supported in part by the US Department of Energy under Award No. DE-FC02-04ER54698.

The significance of sweep in Appalachian hardwood sawlogs

Treesearch

Thomas W., Jr. Church

1973-01-01

Sweep is one of the major stem-form defects in hardwood sawtimber. Some sweep is removed during bucking. But we found sweep of 2 inches or more on 17 percent of the 4,510 logs measured at Appalachian sawmills. Volume deductions for sweep scaled at least 10 percent in 1 of every 7 sample logs and at least 15 percent in 1 of every 9 sample logs. Reduction in the severity...

Research related to variable sweep aircraft development

NASA Technical Reports Server (NTRS)

Polhamus, E. C.; Toll, T. A.

1981-01-01

Development in high speed, variable sweep aircraft research is reviewed. The 1946 Langley wind tunnel studies related to variable oblique and variable sweep wings and results from the X-5 and the XF1OF variable sweep aircraft are discussed. A joint program with the British, evaluation of the British "Swallow", development of the outboard pivot wing/aft tail configuration concept by Langley, and the applied research program that followed and which provided the technology for the current, variable sweep military aircraft is outlined. The relative state of variable sweep as a design option is also covered.

F-14A aircraft high-speed flow simulations

NASA Technical Reports Server (NTRS)

Boppe, C. W.; Rosen, B. S.

1985-01-01

A model of the Grumman/Navy F-14A aircraft was developed for analyses using the NASA/Grumman Transonic Wing-Body Code. Computations were performed for isolated wing and wing fuselage glove arrangements to determine the extent of aerodynamic interference effects which propagate outward onto the main wing outer panel. Additional studies were conducted using the full potential analysis, FLO 22, to calibrate any inaccuracies that might accrue because of small disturbance code limitations. Comparisons indicate that the NASA/Grumman code provides excellent flow simulations for the range of wing sweep angles and flow conditions that will be of interest for the upcoming F-14 Variable Sweep Flight Transition Experiment.

Data Analysis of the Floating Potential Measurement Unit aboard the International Space Station

NASA Technical Reports Server (NTRS)

Barjatya, Aroh; Swenson, Charles M.; Thompson, Donald C.; Wright, Kenneth H., Jr.

2009-01-01

We present data from the Floating Potential Measurement Unit (FPMU), that is deployed on the starboard (S1) truss of the International Space Station. The FPMU is a suite of instruments capable of redundant measurements of various plasma parameters. The instrument suite consists of: a Floating Potential Probe, a Wide-sweeping spherical Langmuir probe, a Narrow-sweeping cylindrical Langmuir Probe, and a Plasma Impedance Probe. This paper gives a brief overview of the instrumentation and the received data quality, and then presents the algorithm used to reduce I-V curves to plasma parameters. Several hours of data is presented from August 5th, 2006 and March 3rd, 2007. The FPMU derived plasma density and temperatures are compared with the International Reference Ionosphere (IRI) and USU-Global Assimilation of Ionospheric Measurement (USU-GAIM) models. Our results show that the derived in-situ density matches the USU-GAIM model better than the IRI, and the derived in-situ temperatures are comparable to the average temperatures given by the IRI.

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

Extended-bandwidth frequency sweeps of a distributed feedback laser using combined injection current and temperature modulation

NASA Astrophysics Data System (ADS)

Hefferman, Gerald; Chen, Zhen; Wei, Tao

2017-07-01

This article details the generation of an extended-bandwidth frequency sweep using a single, communication grade distributed feedback (DFB) laser. The frequency sweep is generated using a two-step technique. In the first step, injection current modulation is employed as a means of varying the output frequency of a DFB laser over a bandwidth of 99.26 GHz. A digital optical phase lock loop is used to lock the frequency sweep speed during current modulation, resulting in a linear frequency chirp. In the second step, the temperature of the DFB laser is modulated, resulting in a shifted starting laser output frequency. A laser frequency chirp is again generated beginning at this shifted starting frequency, resulting in a frequency-shifted spectrum relative to the first recorded data. This process is then repeated across a range of starting temperatures, resulting in a series of partially overlapping, frequency-shifted spectra. These spectra are then aligned using cross-correlation and combined using averaging to form a single, broadband spectrum with a total bandwidth of 510.9 GHz. In order to investigate the utility of this technique, experimental testing was performed in which the approach was used as the swept-frequency source of a coherent optical frequency domain reflectometry system. This system was used to interrogate an optical fiber containing a 20 point, 1-mm pitch length fiber Bragg grating, corresponding to a period of 100 GHz. Using this technique, both the periodicity of the grating in the frequency domain and the individual reflector elements of the structure in the time domain were resolved, demonstrating the technique's potential as a method of extending the sweeping bandwidth of semiconductor lasers for frequency-based sensing applications.

Extended-bandwidth frequency sweeps of a distributed feedback laser using combined injection current and temperature modulation.

PubMed

Hefferman, Gerald; Chen, Zhen; Wei, Tao

2017-07-01

This article details the generation of an extended-bandwidth frequency sweep using a single, communication grade distributed feedback (DFB) laser. The frequency sweep is generated using a two-step technique. In the first step, injection current modulation is employed as a means of varying the output frequency of a DFB laser over a bandwidth of 99.26 GHz. A digital optical phase lock loop is used to lock the frequency sweep speed during current modulation, resulting in a linear frequency chirp. In the second step, the temperature of the DFB laser is modulated, resulting in a shifted starting laser output frequency. A laser frequency chirp is again generated beginning at this shifted starting frequency, resulting in a frequency-shifted spectrum relative to the first recorded data. This process is then repeated across a range of starting temperatures, resulting in a series of partially overlapping, frequency-shifted spectra. These spectra are then aligned using cross-correlation and combined using averaging to form a single, broadband spectrum with a total bandwidth of 510.9 GHz. In order to investigate the utility of this technique, experimental testing was performed in which the approach was used as the swept-frequency source of a coherent optical frequency domain reflectometry system. This system was used to interrogate an optical fiber containing a 20 point, 1-mm pitch length fiber Bragg grating, corresponding to a period of 100 GHz. Using this technique, both the periodicity of the grating in the frequency domain and the individual reflector elements of the structure in the time domain were resolved, demonstrating the technique's potential as a method of extending the sweeping bandwidth of semiconductor lasers for frequency-based sensing applications.

Mechanisms underlying intensity-dependent changes in cortical selectivity for frequency-modulated sweeps.

PubMed

Razak, K A

2012-04-01

Frequency-modulated (FM) sweeps are common components of species-specific vocalizations. The intensity of FM sweeps can cover a wide range in the natural environment, but whether intensity affects neural selectivity for FM sweeps is unclear. Bats, such as the pallid bat, which use FM sweeps for echolocation, are suited to address this issue, because the intensity of echoes will vary with target distance. In this study, FM sweep rate selectivity of pallid bat auditory cortex neurons was measured using downward sweeps at different intensities. Neurons became more selective for FM sweep rates present in the bat's echolocation calls as intensity increased. Increased selectivity resulted from stronger inhibition of responses to slower sweep rates. The timing and bandwidth of inhibition generated by frequencies on the high side of the excitatory tuning curve [sideband high-frequency inhibition (HFI)] shape rate selectivity in cortical neurons in the pallid bat. To determine whether intensity-dependent changes in FM rate selectivity were due to altered inhibition, the timing and bandwidth of HFI were quantified at multiple intensities using the two-tone inhibition paradigm. HFI arrived faster relative to excitation as sound intensity increased. The bandwidth of HFI also increased with intensity. The changes in HFI predicted intensity-dependent changes in FM rate selectivity. These data suggest that neural selectivity for a sweep parameter is not static but shifts with intensity due to changes in properties of sideband inhibition.

Origin of high carrier mobility and low residual stress in RF superimposed DC sputtered Al doped ZnO thin film for next generation flexible devices

NASA Astrophysics Data System (ADS)

Kumar, Naveen; Dubey, Ashish; Bahrami, Behzad; Venkatesan, S.; Qiao, Qiquan; Kumar, Mukesh

2018-04-01

In this work, the energy and flux of high energetic ions were controlled by RF superimposed DC sputtering process to increase the grain size and suppress grain boundary potential with minimum residual stress in Al doped ZnO (AZO) thin film. AZO thin films were deposited at different RF/(RF + DC) ratios by keeping total power same and were investigated for their electrical, optical, structural and nanoscale grain boundaries potential. All AZO thin film showed high crystallinity and orientation along (002) with peak shift as RF/(RF + DC) ratio increased from 0.0, pure DC, to 1.0, pure RF. This peak shift was correlated with high residual stress in as-grown thin film. AZO thin film grown at mixed RF/(RF + DC) of 0.75 showed high electron mobility, low residual stress and large crystallite size in comparison to other AZO thin films. The nanoscale grain boundary potential was mapped using Kelvin Probe Force Microscopy in all AZO thin film and it was observed that carrier mobility is controlled not only by grains size but also by grain boundary potential. The XPS analysis confirms the variation in oxygen vacancies and zinc interstitials which explain the origin of low grain boundaries potential and high carrier mobility in AZO thin film deposited at 0.75 RF/(RF + DC) ratio. This study proposes a new way to control the grain size and grain boundary potential to further tune the optoelectronic-mechanical properties of AZO thin films for next generation flexible and optoelectronic devices.

Improved computational treatment of transonic flow about swept wings

NASA Technical Reports Server (NTRS)

Ballhaus, W. F.; Bailey, F. R.; Frick, J.

1976-01-01

Relaxation solutions to classical three-dimensional small-disturbance (CSD) theory for transonic flow about lifting swept wings are reported. For such wings, the CSD theory was found to be a poor approximation to the full potential equation in regions of the flow field that are essentially two-dimensional in a plane normal to the sweep direction. The effect of this deficiency on the capture of embedded shock waves in terms of (1) the conditions under which shock waves can exist and (2) the relations they must satisfy when they do exist is emphasized. A modified small-disturbance (MSD) equation, derived by retaining two previously neglected terms, was proposed and shown to be a consistent approximation to the full potential equation over a wider range of sweep angles. The effect of these extra terms is demonstrated by comparing CSD, MSD, and experimental wing surface pressures.

Effect of anodic treatment on the electrocatalytic activity of superficial Raney nickel catalyst in cathodic hydrogen

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

Korovin, N.V.; Kozlova, N.I.; Kumenko, M.V.

This work is concerned with the effect of oxidation on the activity of Raney nickel catalyst in cathodic hydrogen evolution. The superficial Raney nickel catalyst (nickel SRC) was prepared by a previously described procedure. The surface of the nickel SRC was oxidized by applying an anodic sweep over the potential range from 0.25 to 1.00 V with a potential sweep rate of 1 mV/sec. The rate of cathodic hydrogen evolution increases after pretreatment of the surface of nickel SRC by application of an anodic pulse. A significant increase in the reaction rate most probably is due to oxygen adsorption onmore » the nickel SRC surface. The largest increase in the amount of weakly bound hydrogen corresponds to the most active electrode. Oxidation of the nickel surface by an anodic pulse causes both an acceleration and a retardation of the cathodic hydrogen evolution reaction.« less

Influence of high-conductivity buffer composition on field-enhanced sample injection coupled to sweeping in CE.

PubMed

Anres, Philippe; Delaunay, Nathalie; Vial, Jérôme; Thormann, Wolfgang; Gareil, Pierre

2013-02-01

The aim of this work was to clarify the mechanism taking place in field-enhanced sample injection coupled to sweeping and micellar EKC (FESI-Sweep-MEKC), with the utilization of two acidic high-conductivity buffers (HCBs), phosphoric acid or sodium phosphate buffer, in view of maximizing sensitivity enhancements. Using cationic model compounds in acidic media, a chemometric approach and simulations with SIMUL5 were implemented. Experimental design first enabled to identify the significant factors and their potential interactions. Simulation demonstrates the formation of moving boundaries during sample injection, which originate at the initial sample/HCB and HCB/buffer discontinuities and gradually change the compositions of HCB and BGE. With sodium phosphate buffer, the HCB conductivity increased during the injection, leading to a more efficient preconcentration by staking (about 1.6 times) than with phosphoric acid alone, for which conductivity decreased during injection. For the same injection time at constant voltage, however, a lower amount of analytes was injected with sodium phosphate buffer than with phosphoric acid. Consequently sensitivity enhancements were lower for the whole FESI-Sweep-MEKC process. This is why, in order to maximize sensitivity enhancements, it is proposed to work with sodium phosphate buffer as HCB and to use constant current during sample injection. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Students' Reasoning When Tackling Electric Field and Potential in Explanation of DC Resistive Circuits

ERIC Educational Resources Information Center

Leniz, Ane; Zuza, Kristina; Guiasola, Jenaro

2017-01-01

This study examines the causal reasoning that university students use to explain how dc circuits work. We analyze how students use the concepts of electric field and potential difference in their explanatory models of dc circuits, and what kinds of reasoning they use at the macroscopic and microscopic levels in their explanations. This knowledge…

Still from High-Clouds Jupiter Movie

NASA Technical Reports Server (NTRS)

2000-01-01

This image is one of seven from the narrow-angle camera on NASA's Cassini spacecraft assembled as a brief movie of high-altitude cloud movements on Jupiter. It was taken in early October 2000.

The images were taken at a wavelength that is absorbed by methane, one chemical in Jupiter's lower clouds. So, dark areas are relatively free of high clouds, and the camera sees through to the methane in a lower level. Bright areas are places with high, thick clouds that shield the methane below.

The area shown covers latitudes from 50 degrees north to 50 degrees south and a 100-degree sweep of longitude.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

Effects of Wing Sweep on In-flight Boundary-layer Transition for a Laminar Flow Wing at Mach Numbers from 0.60 to 0.79

NASA Technical Reports Server (NTRS)

Anderson, Bianca Trujillo; Meyer, Robert R., Jr.

1990-01-01

The variable sweep transition flight experiment (VSTFE) was conducted on an F-14A variable sweep wing fighter to examine the effect of wing sweep on natural boundary layer transition. Nearly full span upper surface gloves, extending to 60 percent chord, were attached to the F-14 aircraft's wings. The results are presented of the glove 2 flight tests. Glove 2 had an airfoil shape designed for natural laminar flow at a wing sweep of 20 deg. Sample pressure distributions and transition locations are presented with the complete results tabulated in a database. Data were obtained at wing sweeps of 15, 20, 25, 30, and 35 deg, at Mach numbers ranging from 0.60 to 0.79, and at altitudes ranging from 10,000 to 35,000 ft. Results show that a substantial amount of laminar flow was maintained at all the wing sweeps evaluated. The maximum transition Reynolds number obtained was 18.6 x 10(exp 6) at 15 deg of wing sweep, Mach 0.75, and at an altitude of 10,000 ft.

Determination of Oebalus pugnax (Hemiptera: Pentatomidae) spatial pattern in rice and development of visual sampling methods and population sampling plans.

PubMed

Espino, L; Way, M O; Wilson, L T

2008-02-01

Commercial rice, Oryza sativa L., fields in southeastern Texas were sampled during 2003 and 2004, and visual samples were compared with sweep net samples. Fields were sampled at different stages of panicle development, times of day, and by different operators. Significant differences were found between perimeter and within field sweep net samples, indicating that samples taken 9 m from the field margin overestimate within field Oebalus pugnax (F.) (Hemiptera: Pentatomidae) populations. Time of day did not significantly affect the number of O. pugnax caught with the sweep net; however, there was a trend to capture more insects during morning than afternoon. For all sampling methods evaluated during this study, O. pugnax was found to have an aggregated spatial pattern at most densities. When comparing sweep net with visual sampling methods, one sweep of the "long stick" and two sweeps of the "sweep stick" correlated well with the sweep net (r2 = 0.639 and r2 = 0.815, respectively). This relationship was not affected by time of day of sampling, stage of panicle development, type of planting or operator. Relative cost-reliability, which incorporates probability of adoption, indicates the visual methods are more cost-reliable than the sweep net for sampling O.

Mitigation of divertor heat loads by strike point sweeping in high power JET discharges

NASA Astrophysics Data System (ADS)

Silburn, S. A.; Matthews, G. F.; Challis, C. D.; Frigione, D.; Graves, J. P.; Mantsinen, M. J.; Belonohy, E.; Hobirk, J.; Iglesias, D.; Keeling, D. L.; King, D.; Kirov, K.; Lennholm, M.; Lomas, P. J.; Moradi, S.; Sips, A. C. C.; Tsalas, M.; Contributors, JET

2017-12-01

Deliberate periodic movement (sweeping) of the high heat flux divertor strike lines in tokamak plasmas can be used to manage the heat fluxes experienced by exhaust handling plasma facing components, by spreading the heat loads over a larger surface area. Sweeping has recently been adopted as a routine part of the main high performance plasma configurations used on JET, and has enabled pulses with 30 MW plasma heating power and 10 MW radiation to run for 5 s without overheating the divertor tiles. We present analysis of the effectiveness of sweeping for divertor temperature control on JET, using infrared camera data and comparison with a simple 2D heat diffusion model. Around 50% reduction in tile temperature rise is obtained with 5.4 cm sweeping compared to the un-swept case, and the temperature reduction is found to scale slower than linearly with sweeping amplitude in both experiments and modelling. Compatibility of sweeping with high fusion performance is demonstrated, and effects of sweeping on the edge-localised mode behaviour of the plasma are reported and discussed. The prospects of using sweeping in future JET experiments with up to 40 MW heating power are investigated using a model validated against existing experimental data.

Miniature Ion-Mobility Spectrometer

NASA Technical Reports Server (NTRS)

Hartley, Frank T.

2006-01-01

The figure depicts a proposed miniature ion-mobility spectrometer that would be fabricated by micromachining. Unlike prior ion-mobility spectrometers, the proposed instrument would not be based on a time-of-flight principle and, consequently, would not have some of the disadvantageous characteristics of prior time-of-flight ion-mobility spectrometers. For example, one of these characteristics is the need for a bulky carrier-gas-feeding subsystem that includes a shutter gate to provide short pulses of gas in order to generate short pulses of ions. For another example, there is need for a complex device to generate pulses of ions from the pulses of gas and the device is capable of ionizing only a fraction of the incoming gas molecules; these characteristics preclude miniaturization. In contrast, the proposed instrument would not require a carrier-gas-feeding subsystem and would include a simple, highly compact device that would ionize all the molecules passing through it. The ionization device in the proposed instrument would be a 0.1-micron-thick dielectric membrane with metal electrodes on both sides. Small conical holes would be micromachined through the membrane and electrodes. An electric potential of the order of a volt applied between the membrane electrodes would give rise to an electric field of the order of several megavolts per meter in the submicron gap between the electrodes. An electric field of this magnitude would be sufficient to ionize all the molecules that enter the holes. Ionization (but not avalanche arcing) would occur because the distance between the ionizing electrodes would be less than the mean free path of gas molecules at the operating pressure of instrument. An accelerating grid would be located inside the instrument, downstream from the ionizing membrane. The electric potential applied to this grid would be negative relative to the potential on the inside electrode of the ionizing membrane and would be of a magnitude sufficient to generate a moderate electric field. Positive ions leaving the membrane holes would be accelerated in this electric field. The resulting flux of ions away from the ionization membrane would create a partial vacuum that would draw more of the gas medium through the membrane. The figure depicts a filter electrode and detector electrodes located along the sides of a drift tube downstream from the accelerator electrode. These electrodes would apply a transverse AC electric field superimposed on a ramped DC electric field. The AC field would effect differential transverse dispersal of ions. At a given instant of time, the trajectories of most of the ions would be bent toward the electrodes, causing most of the ions to collide with the electrodes and thereby become neutralized. The DC field would partly counteract the dispersive effect of the AC field, straightening the trajectories of a selected species of ions; the selection would vary with the magnitude of the applied DC field. The straightening of the trajectories of the selected ions would enable them to pass into the region between the detector electrodes. Depending on the polarity of the voltage applied to the detector electrodes, the electric field between the detector electrodes would draw the selected ions to one of these electrodes. Hence, the current collected by one of the detector electrodes would be a measure of the abundance of ions of the selected species. The ramping of the filter- electrode DC voltage would sweep the selection of ions through the spectrum of ionic species.

Adiabatic sweep pulses for earth's field NMR with a surface coil

NASA Astrophysics Data System (ADS)

Conradi, Mark S.; Altobelli, Stephen A.; Sowko, Nicholas J.; Conradi, Susan H.; Fukushima, Eiichi

2018-03-01

Adiabatic NMR sweep pulses are described for inversion and excitation in very low magnetic fields B0 and with broad distribution of excitation field amplitude B1. Two aspects distinguish the low field case: (1) when B1 is comparable to or greater than B0, the rotating field approximation fails and (2) inversion sweeps cannot extend to values well below the Larmor frequency because they would approach or pass through zero frequency. Three approaches to inversion are described. The first is a conventional tangent frequency sweep down to the Larmor frequency, a 180° phase shift, and a sweep back up to the starting frequency. The other two are combined frequency and amplitude sweeps covering a narrower frequency range; one is a symmetric sweep from above to below the Larmor frequency and the other uses a smooth decrease of B1 immediately before and after the 180° phase shift. These two AM/FM sweeps show excellent inversion efficiencies over a wide range of B1, a factor of 30 or more. We also demonstrate an excitation sweep that works well in the presence of the same wide range of B1. We show that the primary effect of the counter-rotating field (i.e., at low B0) is that the magnetization suffers large, periodic deviations from where it would be at large B0. Thus, successful sweep pulses must avoid any sharp features in the amplitude, phase, or frequency.

Effect of a direct current bias on the electrohydrodynamic performance of a surface dielectric barrier discharge actuator for airflow control

NASA Astrophysics Data System (ADS)

Yan, Huijie; Yang, Liang; Qi, Xiaohua; Ren, Chunsheng

2015-02-01

The effect of a DC bias on the electrohydrodynamics (EHD) force induced by a surface dielectric barrier AC discharge actuator for airflow control at the atmospheric pressure is investigated. The measurement of the surface potential due to charge deposition at different DC biases is carried out by using a special designed corona like discharge potential probe. From the surface potential data, the plasma electromotive force is shown not affected much by the DC biases except for some reduction of the DC bias near the exposed electrode edge for the sheath-like configuration. The total thrust is measured by an analytical balance, and an almost linear relationship to the potential voltage at the exposed electrode edge is found for the direct thrust force. The temporally averaged ionic wind characteristics are investigated by Pitot tube sensor and schlieren visualization system. It is found that the ionic wind velocity profiles with different DC biases are almost the same in the AC discharge plasma area but gradually diversified in the further downstream area as well as the upper space away from the discharge plasma area. Also, the DC bias can significantly modify the topology of the ionic wind produced by the AC discharge actuator. These results can provide an insight into how the DC biases to affect the force generation.

[Topography structure and flocculation mechanism of polymeric phosphate ferric sulfate (PPFS)].

PubMed

Zheng, Huai-li; Zhang, Hui-qin; Jiang, Shao-jie; Li, Fang; Jiao, Shi-jun; Fang, Hui-li

2011-05-01

Characteristics of polymeric phosphate ferric sulfate (PPFS) were investigated using FTIR (Fourier transform infrared spectrometer), XRD (X-ray diffraction) and SEM (scanning electron microscope) in the present study. The formed PPFS structure and morphology were stereo meshwork, which was clustered and close to coral reef, synthesis of high charge density, bioactive polyhydroxy and mixed polynuclear complex PPFS. The results showed that charge neutralization of PPFS had not played a decisive role in the coagulation beaker test and the zeta potential proved that PPFS was largely affected by bridging and netting sweep. Therefore, the coagulation mechanisms of PPFS were mainly composed of charge neutralization, adsorption bridging and netting sweep mechanisms.

Ponderomotive electron acceleration in a silicon-based nanoplasmonic waveguide.

PubMed

Sederberg, S; Elezzabi, A Y

2014-10-17

Ponderomotive electron acceleration is demonstrated in a semiconductor-loaded nanoplasmonic waveguide. Photogenerated free carriers are accelerated by the tightly confined nanoplasmonic fields and reach energies exceeding the threshold for impact ionization. Broadband (375 nm ≤ λ ≤ 650  nm) white light emission is observed from the nanoplasmonic waveguides. Exponential growth of visible light emission confirms the exponential growth of the electron population, demonstrating the presence of an optical-field-driven electron avalanche. Electron sweeping dynamics are visualized using pump-probe measurements, and a sweeping time of 1.98 ± 0.40 ps is measured. These findings offer a means to harness the potential of the emerging field of ultrafast nonlinear nanoplasmonics.

Reproductive health in eight navies: a comparative report on education, prevention services, and policies on pregnancy, maternity/paternity leaves, and childcare.

PubMed

Fjord, Lakshmi; Ames, Genevieve

2009-03-01

As occupational cultures, navies are remarkable for an ability to achieve far-reaching cultural and behavioral effects by both sweeping and incremental policy changes. Therefore, navy policies for reproductive health education and services, childcare, and maternity and paternity leaves have potential to be at the vanguard of gender parity efforts to successfully integrate women into once male-only occupations. This article provides summaries of reproductive health education programs, pregnancy prevention services, and policies currently in effect in eight navies where women work alongside male peers as sailors and officers. Our objective is to bring together comparative data that is hard to find by other means, which may prove useful to researchers, policy-makers, and naval personnel. Project methodology involved questionnaires sent to naval attaches stationed in embassies in Washington, DC, who referred sections to their appropriate departments. The results are quotations from completed questionnaires and policies sent from the navies of Germany, Latvia, the Netherlands, Norway, South Africa, Spain, the United Kingdom, and the United States. Policies under review include sexual conduct, pregnancy, and maternity and paternity leaves. We also report the latest available statistical data regarding women in these navies, such as numbers of women, percentages of navy women vs. total military women, and dates of women's inclusion as naval personnel.

Power- and Low-Resistance-State-Dependent, Bipolar Reset-Switching Transitions in SiN-Based Resistive Random-Access Memory

NASA Astrophysics Data System (ADS)

Kim, Sungjun; Park, Byung-Gook

2016-08-01

A study on the bipolar-resistive switching of an Ni/SiN/Si-based resistive random-access memory (RRAM) device shows that the influences of the reset power and the resistance value of the low-resistance state (LRS) on the reset-switching transitions are strong. For a low LRS with a large conducting path, the sharp reset switching, which requires a high reset power (>7 mW), was observed, whereas for a high LRS with small multiple-conducting paths, the step-by-step reset switching with a low reset power (<7 mW) was observed. The attainment of higher nonlinear current-voltage ( I-V) characteristics in terms of the step-by-step reset switching is due to the steep current-increased region of the trap-controlled space charge-limited current (SCLC) model. A multilevel cell (MLC) operation, for which the reset stop voltage ( V STOP) is used in the DC sweep mode and an incremental amplitude is used in the pulse mode for the step-by-step reset switching, is demonstrated here. The results of the present study suggest that well-controlled conducting paths in a SiN-based RRAM device, which are not too strong and not too weak, offer considerable potential for the realization of low-power and high-density crossbar-array applications.

TAC Variable Sweep Model

NASA Image and Video Library

1960-05-14

Project: Wing Sweep Range Series TAC Variable Sweep Model configure 8 A. Taken at 8 foot tunnels building 641. L60-3412 through 3416 Model of proposed military supersonic attack airplane shows wing sweep range. TAC Models taken at the 8 Foot Tunnel. Photograph published in Sixty Years of Aeronautical Research 1917-1977 By David A. Anderton. A NASA publication. Page 53.

A linearly frequency-swept high-speed-rate multi-wavelength laser for optical coherence tomography

NASA Astrophysics Data System (ADS)

Wang, Qiyu; Wang, Zhaoying; Yuan, Quan; Ma, Rui; Du, Tao; Yang, Tianxin

2017-02-01

We proposed and demonstrated a linearly frequency-swept multi-wavelength laser source for optical coherence tomography (OCT) eliminating the need of wavenumber space resampling in the postprocessing progress. The source consists of a multi-wavelength fiber laser source (MFS) and an optical sweeping loop. In this novel laser source, an equally spaced multi-wavelength laser is swept simultaneously by a certain step each time in the frequency domain in the optical sweeping loop. The sweeping step is determined by radio frequency (RF) signal which can be precisely controlled. Thus the sweeping behavior strictly maintains a linear relationship between time and frequency. We experimentally achieved linear time-frequency sweeping at a sweeping rate of 400 kHz with our laser source.

Simulation of Sweep-Jet Flow Control, Single Jet and Full Vertical Tail

NASA Technical Reports Server (NTRS)

Childs, Robert E.; Stremel, Paul M.; Garcia, Joseph A.; Heineck, James T.; Kushner, Laura K.; Storms, Bruce L.

2016-01-01

This work is a simulation technology demonstrator, of sweep jet flow control used to suppress boundary layer separation and increase the maximum achievable load coefficients. A sweep jet is a discrete Coanda jet that oscillates in the plane parallel to an aerodynamic surface. It injects mass and momentum in the approximate streamwise direction. It also generates turbulent eddies at the oscillation frequency, which are typically large relative to the scales of boundary layer turbulence, and which augment mixing across the boundary layer to attack flow separation. Simulations of a fluidic oscillator, the sweep jet emerging from a nozzle downstream of the oscillator, and an array of sweep jets which suppresses boundary layer separation are performed. Simulation results are compared to data from a dedicated validation experiment of a single oscillator and its sweep jet, and from a wind tunnel test of a full-scale Boeing 757 vertical tail augmented with an array of sweep jets. A critical step in the work is the development of realistic time-dependent sweep jet inflow boundary conditions, derived from the results of the single-oscillator simulations, which create the sweep jets in the full-tail simulations. Simulations were performed using the computational fluid dynamics (CFD) solver Overow, with high-order spatial discretization and a range of turbulence modeling. Good results were obtained for all flows simulated, when suitable turbulence modeling was used.

Simplified energy-balance model for pragmatic multi-dimensional device simulation

NASA Astrophysics Data System (ADS)

Chang, Duckhyun; Fossum, Jerry G.

1997-11-01

To pragmatically account for non-local carrier heating and hot-carrier effects such as velocity overshoot and impact ionization in multi-dimensional numerical device simulation, a new simplified energy-balance (SEB) model is developed and implemented in FLOODS[16] as a pragmatic option. In the SEB model, the energy-relaxation length is estimated from a pre-process drift-diffusion simulation using the carrier-velocity distribution predicted throughout the device domain, and is used without change in a subsequent simpler hydrodynamic (SHD) simulation. The new SEB model was verified by comparison of two-dimensional SHD and full HD DC simulations of a submicron MOSFET. The SHD simulations yield detailed distributions of carrier temperature, carrier velocity, and impact-ionization rate, which agree well with the full HD simulation results obtained with FLOODS. The most noteworthy feature of the new SEB/SHD model is its computational efficiency, which results from reduced Newton iteration counts caused by the enhanced linearity. Relative to full HD, SHD simulation times can be shorter by as much as an order of magnitude since larger voltage steps for DC sweeps and larger time steps for transient simulations can be used. The improved computational efficiency can enable pragmatic three-dimensional SHD device simulation as well, for which the SEB implementation would be straightforward as it is in FLOODS or any robust HD simulator.

Lanthanide Diphthalocyanines. Electrochemistry and Display Applications.

DTIC Science & Technology

1982-01-01

transients, cyclic voltametry (Nicholson and Galiardi, 1977, 1978; Noskalev and Shapkin, 1978). and a novel solid-state moving-boundary technique...was confirmed for the reverse process by linear potential- sweep voltammetry. Although the hydrazine hydrate my not have been simply an inert solvent

DC/DC Converter Stability Testing Study

NASA Technical Reports Server (NTRS)

Wang, Bright L.

2008-01-01

This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

Sweep visually evoked potentials and visual findings in children with West syndrome.

PubMed

de Freitas Dotto, Patrícia; Cavascan, Nívea Nunes; Berezovsky, Adriana; Sacai, Paula Yuri; Rocha, Daniel Martins; Pereira, Josenilson Martins; Salomão, Solange Rios

2014-03-01

West syndrome (WS) is a type of early childhood epilepsy characterized by progressive neurological development deterioration that includes vision. To demonstrate the clinical importance of grating visual acuity thresholds (GVA) measurement by sweep visually evoked potentials technique (sweep-VEP) as a reliable tool for evaluation of the visual cortex status in WS children. This is a retrospective study of the best-corrected binocular GVA and ophthalmological features of WS children referred for the Laboratory of Clinical Electrophysiology of Vision of UNIFESP from 1998 to 2012 (Committee on Ethics in Research of UNIFESP n° 0349/08). The GVA deficit was calculated by subtracting binocular GVA score (logMAR units) of each patient from the median values of age norms from our own lab and classified as mild (0.1-0.39 logMAR), moderate (0.40-0.80 logMAR) or severe (>0.81 logMAR). Associated ophthalmological features were also described. Data from 30 WS children (age from 6 to 108 months, median = 14.5 months, mean ± SD = 22.0 ± 22.1 months; 19 male) were analyzed. The majority presented severe GVA deficit (0.15-1.44 logMAR; mean ± SD = 0.82 ± 0.32 logMAR; median = 0.82 logMAR), poor visual behavior, high prevalence of strabismus and great variability in ocular positioning. The GVA deficit did not vary according to gender (P = .8022), WS type (P = .908), birth age (P = .2881), perinatal oxygenation (P = .7692), visual behavior (P = .8789), ocular motility (P = .1821), nystagmus (P = .2868), risk of drug-induced retinopathy (P = .4632) and participation in early visual stimulation therapy (P = .9010). The sweep-VEP technique is a reliable tool to classify visual system impairment in WS children, in agreement with the poor visual behavior exhibited by them. Copyright © 2013 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Street dust: implications for stormwater and air quality, and environmental through street sweeping.

PubMed

Calvillo, Steven J; Williams, E Spencer; Brooks, Bryan W

2015-01-01

Street dust represents a source of dual potential risk to stormwater and air quality. It has been well documented that street dust washes into local watersheds and can degrade water quality. Research has also demonstrated that ambient particulate matter (PM10) , which is associated with adverse health outcomes, can arise from resuspension of accumulated street dust. Furthermore, many contaminants, including metals, are present at higher concentrations in the smallest available particles, which are more likely to be resuspended in air and stormwater runoff. Although street cleaning is listed as a best management practice for storm water quality by the EPA, data are limited on the critical parameters (technology, environment, usage), which determine the effectiveness of any street cleaning program, particularly in the peer-reviewed literature. The purpose of the present study was to develop a comprehensive understanding of the efficacy of various street cleaning technologies and practices to protect both water quality and public health. Few studies have compared the effectiveness of street sweeping technologies to remove street dust. Unfortunately, the dearth of comprehensive data on exposure, contaminant concentrations, and efficacy of various sweeping technologies and strategies precludes developing quantitative estimates for potential risk to humans and the environment. Based on the few studies available, regenerative air street sweepers appear to provide the most benefit with regard to collection of small particles and prevention of re-entrainment. It is also clear from the available data that local conditions, climate, and specific needs are critical determinants of the ideal street sweeping strategy (technology, frequency, speed, targeted areas, etc.). Given the critical need for protection of water and air quality in rapidly expanding urban regions (e.g., megacities), further research is necessary to develop best practices for street dust management. Herein, we provide a framework for future experimental studies to support risk-based assessments of street cleaning technologies.

Solar Photovoltaic DC Systems: Basics and Safety: Preprint

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

McNutt, Peter F; Sekulic, William R; Dreifuerst, Gary

Solar Photovoltaic (PV) systems are common and growing with 42.4 GW installed capacity in U.S. (almost 15 GW added in 2016). This paper will help electrical workers, and emergency responders understand the basic operating principles and hazards of PV DC arrays. We briefly discuss the following aspects of solar photovoltaic (PV) DC systems: the effects of solar radiation and temperature on output power; PV module testing standards; common system configurations; a simple PV array sizing example; NEC guidelines and other safety features; DC array commissioning, periodic maintenance and testing; arc-flash hazard potential; how electrical workers and emergency responders can andmore » do work safely around PV arrays; do moonlight and artificial lighting pose a real danger; typical safe operating procedures; and other potential DC-system hazards to be aware of. We also present some statistics on PV DC array electrical incidents and injuries. Safe PV array operation is possible with a good understanding of PV DC arrays basics and having good safe operating procedures in place.« less

Directional Selectivity for FM Sweeps in the Suprageniculate Nucleus of the Mustached Bat Medial Geniculate Body

PubMed Central

O’NEILL, WILLIAM E.; BRIMIJOIN, W. OWEN

2014-01-01

Mustached bats emit echolocation and communication calls containing both constant frequency (CF) and frequency-modulated (FM) components. Previously we found that 86% of neurons in the ventral division of the external nucleus of the inferior colliculus (ICXv) were directionally selective for linear FM sweeps and that selectivity was dependent on sweep rate. The ICXv projects to the suprageniculate nucleus (Sg) of the medial geniculate body. In this study, we isolated 37 single units in the Sg and measured their responses to best excitatory frequency (BEF) tones and linear 12-kHz upward and downward FM sweeps centered on the BEF. Sweeps were presented at durations of 30, 12, and 4 ms, yielding modulation rates of 400, 1,000, and 3,000 kHz/s. Spike count versus level functions were obtained at each modulation rate and compared with BEF controls. Sg units responded well to both tones and FM sweeps. BEFs clustered at 58 kHz, corresponding to the dominant CF component of the sonar signal. Spike count functions for both tones and sweeps were predominantly non-monotonic. FM directional selectivity was significant in 53–78% of the units, depending on modulation rate and level. Units were classified as up-selective (52%), down-selective (24%), or bi-directional (non-selective, 16%); a few units (8%) showed preferences that were either rate- or level-dependent. Most units showed consistent directional preferences at all SPLs and modulation rates tested, but typically showed stronger selectivity at lower sweep rates. Directional preferences were attributable to suppression of activity by sweeps in the non-preferred direction (~80% of units) and/or facilitation by sweeps in the preferred direction (~20–30%). Latencies for BEF tones ranged from 4.9 to 25.7 ms. Latencies for FM sweeps typically varied linearly with sweep duration. Most FM latency-duration functions had slopes ranging from 0.4 to 0.6, suggesting that the responses were triggered by the BEF. Latencies for BEF tones and FM sweeps were significantly correlated in most Sg units, i.e., the response to FM was temporally related to the occurrence of the BEF in the FM sweep. FM latency declined relative to BEF latency as modulation rate increased, suggesting that at higher rates response is triggered by frequencies in the sweep preceding the BEF. We conclude that Sg and ICXv units have similar, though not identical, response properties. Sg units are predominantly upsweep selective and could respond to either or both the CF and FM components in biosonar signals in a number of echolocation scenarios, as well as to a variety of communication sounds. PMID:12091543

Technical Challenges and Potential Solutions for Cross-Country Multi-Terminal Superconducting DC Power Cables

NASA Astrophysics Data System (ADS)

Al-Taie, A.; Graber, L.; Pamidi, S. V.

2017-12-01

Opportunities for applications of high temperature superconducting (HTS) DC power cables for long distance power transmission in increasing the reliability of the electric power grid and to enable easier integration of distributed renewable sources into the grid are discussed. The gaps in the technology developments both in the superconducting cable designs and cryogenic systems as well as power electronic devices are identified. Various technology components in multi-terminal high voltage DC power transmission networks and the available options are discussed. The potential of ongoing efforts in the development of superconducting DC transmission systems is discussed.

The frequency and level of sweep in mixed hardwood saw logs in the eastern United States

Treesearch

Peter Hamner; Marshall S. White; Philip A. Araman

2007-01-01

Hardwood sawmills traditionally saw logs in a manner that either orients sawlines parallel to the log central axis (straight sawing) or the log surface (allowing for taper). Sweep is characterized as uniform curvature along the entire length of a log. For logs with sweep, lumber yield losses from straight and taper sawing increase with increasing levels of sweep. Curve...

Measurements of the eigenfunction of reversed shear Alfvén eigenmodes that sweep downward in frequency

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

Heidbrink, W. W.; Austin, M. E.; Spong, D. A.

2013-08-15

Reversed shear Alfvén eigenmodes (RSAEs) usually sweep upward in frequency when the minimum value of the safety factor q{sub min} decreases in time. On rare occasions, RSAEs sweep downward prior to the upward sweep. Electron cyclotron emission measurements show that the radial eigenfunction during the downsweeping phase is similar to the eigenfunction of normal, upsweeping RSAEs.

A Parallel Fast Sweeping Method for the Eikonal Equation

NASA Astrophysics Data System (ADS)

Baker, B.

2017-12-01

Recently, there has been an exciting emergence of probabilistic methods for travel time tomography. Unlike gradient-based optimization strategies, probabilistic tomographic methods are resistant to becoming trapped in a local minimum and provide a much better quantification of parameter resolution than, say, appealing to ray density or performing checkerboard reconstruction tests. The benefits associated with random sampling methods however are only realized by successive computation of predicted travel times in, potentially, strongly heterogeneous media. To this end this abstract is concerned with expediting the solution of the Eikonal equation. While many Eikonal solvers use a fast marching method, the proposed solver will use the iterative fast sweeping method because the eight fixed sweep orderings in each iteration are natural targets for parallelization. To reduce the number of iterations and grid points required the high-accuracy finite difference stencil of Nobel et al., 2014 is implemented. A directed acyclic graph (DAG) is created with a priori knowledge of the sweep ordering and finite different stencil. By performing a topological sort of the DAG sets of independent nodes are identified as candidates for concurrent updating. Additionally, the proposed solver will also address scalability during earthquake relocation, a necessary step in local and regional earthquake tomography and a barrier to extending probabilistic methods from active source to passive source applications, by introducing an asynchronous parallel forward solve phase for all receivers in the network. Synthetic examples using the SEG over-thrust model will be presented.

Background sounds contribute to spectrotemporal plasticity in primary auditory cortex.

PubMed

Moucha, Raluca; Pandya, Pritesh K; Engineer, Navzer D; Rathbun, Daniel L; Kilgard, Michael P

2005-05-01

The mammalian auditory system evolved to extract meaningful information from complex acoustic environments. Spectrotemporal selectivity of auditory neurons provides a potential mechanism to represent natural sounds. Experience-dependent plasticity mechanisms can remodel the spectrotemporal selectivity of neurons in primary auditory cortex (A1). Electrical stimulation of the cholinergic nucleus basalis (NB) enables plasticity in A1 that parallels natural learning and is specific to acoustic features associated with NB activity. In this study, we used NB stimulation to explore how cortical networks reorganize after experience with frequency-modulated (FM) sweeps, and how background stimuli contribute to spectrotemporal plasticity in rat auditory cortex. Pairing an 8-4 kHz FM sweep with NB stimulation 300 times per day for 20 days decreased tone thresholds, frequency selectivity, and response latency of A1 neurons in the region of the tonotopic map activated by the sound. In an attempt to modify neuronal response properties across all of A1 the same NB activation was paired in a second group of rats with five downward FM sweeps, each spanning a different octave. No changes in FM selectivity or receptive field (RF) structure were observed when the neural activation was distributed across the cortical surface. However, the addition of unpaired background sweeps of different rates or direction was sufficient to alter RF characteristics across the tonotopic map in a third group of rats. These results extend earlier observations that cortical neurons can develop stimulus specific plasticity and indicate that background conditions can strongly influence cortical plasticity.

Improving the sweeping efficiency of permanganate into low permeable zones to treat TCE: experimental results and model development.

PubMed

Chokejaroenrat, Chanat; Kananizadeh, Negin; Sakulthaew, Chainarong; Comfort, Steve; Li, Yusong

2013-11-19

The residual buildup and treatment of dissolved contaminants in low permeable zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate into LPZs to treat dissolved-phase TCE. This was accomplished by conducting transport experiments that quantified the ability of xanthan-MnO4(-) solutions to penetrate and cover (i.e., sweep) an LPZ that was surrounded by transmissive sands. By incorporating the non-Newtonian fluid xanthan with MnO4(-), penetration of MnO4(-) into the LPZ improved dramatically and sweeping efficiency reached 100% in fewer pore volumes. To quantify how xanthan improved TCE removal, we spiked the LPZ and surrounding sands with (14)C-lableled TCE and used a multistep flooding procedure that quantified the mass of (14)C-TCE oxidized and bypassed during treatment. Results showed that TCE mass removal was 1.4 times greater in experiments where xanthan was employed. Combining xanthan with MnO4(-) also reduced the mass of TCE in the LPZ that was potentially available for rebound. By coupling a multiple species reactive transport model with the Brinkman equation for non-Newtonian flow, the simulated amount of (14)C-TCE oxidized during transport matched experimental results. These observations support the use of xanthan as a means of enhancing MnO4(-) delivery into LPZs for the treatment of dissolved-phase TCE.

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.

Enhancing the mathematical properties of new haplotype homozygosity statistics for the detection of selective sweeps.

PubMed

Garud, Nandita R; Rosenberg, Noah A

2015-06-01

Soft selective sweeps represent an important form of adaptation in which multiple haplotypes bearing adaptive alleles rise to high frequency. Most statistical methods for detecting selective sweeps from genetic polymorphism data, however, have focused on identifying hard selective sweeps in which a favored allele appears on a single haplotypic background; these methods might be underpowered to detect soft sweeps. Among exceptions is the set of haplotype homozygosity statistics introduced for the detection of soft sweeps by Garud et al. (2015). These statistics, examining frequencies of multiple haplotypes in relation to each other, include H12, a statistic designed to identify both hard and soft selective sweeps, and H2/H1, a statistic that conditional on high H12 values seeks to distinguish between hard and soft sweeps. A challenge in the use of H2/H1 is that its range depends on the associated value of H12, so that equal H2/H1 values might provide different levels of support for a soft sweep model at different values of H12. Here, we enhance the H12 and H2/H1 haplotype homozygosity statistics for selective sweep detection by deriving the upper bound on H2/H1 as a function of H12, thereby generating a statistic that normalizes H2/H1 to lie between 0 and 1. Through a reanalysis of resequencing data from inbred lines of Drosophila, we show that the enhanced statistic both strengthens interpretations obtained with the unnormalized statistic and leads to empirical insights that are less readily apparent without the normalization. Copyright © 2015 Elsevier Inc. All rights reserved.

Ohmsett test of NOFI Vee-Sweep and NOFI 600S oilboom. Final report

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

Goodwin, M.J.

1993-10-01

A NOFI Vee-Sweep and a NOFI 600S Oilboom, both manufactured by NOFI TROMSO A/S of Norway, were tested at the Ohmsett test tank in Leonardo, NJ. The V-Shaped Sweep is an oil boom designed for use with a skimmer at the apex of the V-Shaped configuration. Oil is funneled back to the skimmer by the converging sides of the V and concentrated for more efficient skimming. The 60 meter length of the sweep is doubled over to form the V and held in this shape by cross netting at the bottom of the skirt. The bottom netting is claimed tomore » help stabilize the oil in the sweep. The sweep was towed with a 700mm skirt depth and mouth opening of 16 meters. The mouth opening was reduced from the designed 19.8 meters to fit in the tow tank without causing excess blockage. The limiting towing speeds of the sweep were determined with and without oil present, in calm water and in small waves. The sweep's ability to conform to waves was also determined. Towing forces were measured. Limited data on oil loss rates were obtained. Testing confirmed the manufacturer's claim that the sweep can be towed at 1.0 and 1.4 knots with oil in calm water, based on the first loss of oil. The critical tow speed was found to be 3.4 to 3.6 knots in calm water. Oil booms, Tow tank testing.« less

Multiscale modeling and experimental interpretation of perovskite oxide materials in thermochemical energy storage and conversion for application in concentrating solar power

NASA Astrophysics Data System (ADS)

Albrecht, Kevin J.

Decarbonization of the electric grid is fundamentally limited by the intermittency of renewable resources such as wind and solar. Therefore, energy storage will play a significant role in the future of grid-scale energy generation to overcome the intermittency issues. For this reason, concentrating solar power (CSP) plants have been a renewable energy generation technology of interest due to their ability to participate in cost effective and efficient thermal energy storage. However, the ability to dynamically dispatch a CSP plant to meet energy demands is currently limited by the large quantities of sensible thermal energy storage material needed in a molten salt plant. Perovskite oxides have been suggested as a thermochemical energy storage material to enhance the energy storage capabilities of particle-based CSP plants, which combine sensible and chemical modes of energy storage. In this dissertation, computational models are used to establish the thermochemical energy storage potential of select perovskite compositions, identify system configurations that promote high values of energy storage and solar-to-electric efficiency, assess the kinetic and transport limitation of the chemical mode of energy storage, and create receiver and reoxidation reactor models capable of aiding in component design. A methodology for determining perovskite thermochemical energy storage potential is developed based on point defect models to represent perovskite non-stoichiometry as a function of temperature and gas phase oxygen partial pressure. The thermodynamic parameters necessary for the model are extracted from non-stoichiometry measurements by fitting the model using an optimization routine. The procedure is demonstrated for Ca0.9Sr0.1MnO 3-d which displayed combined energy storage values of 705.7 kJ/kg -1 by cycling between 773 K and 0.21 bar oxygen to 1173 K and 10 -4 bar oxygen. Thermodynamic system-level models capable of exploiting perovskite redox chemistry for energy storage in CSP plants are presented. Comparisons of sweep gas and vacuum pumping reduction as well as hot storage conditions indicate that solar-to-electric efficiencies are higher for sweep gas reduction system at equivalent values of energy storage if the energy parasitics of commercially available devices are considered. However, if vacuum pump efficiency between 15% and 30% can be achieved, the reduction methods will be approximately equal. Reducing condition oxygen partial pressures below 10-3 bar for sweep gas reduction and 10-2 bar for vacuum pumping reduction result in large electrical parasitics, which significantly reduce solar-to-electric efficiency. A model based interpretation of experimental measurements made for perovskite redox cycling using sweep gas in a packed bed is presented. The model indicates that long reduction times for equilibrating perovskites with low oxygen partial pressure sweep gas, compared to reoxidation, are primarily due to the oxygen carrying capacity of high purity sweep gas and not surface kinetic limitations. Therefore, achieving rapid reduction in the limited receiver residence time will be controlled by the quantity of sweep gas introduced. Effective kinetic parameters considering surface reaction and radial particle diffusion are fit to the experimental data. Variable order rate expressions without significant particle radial diffusion limitations are shown to be capable of representing the reduction and oxidation data. Modeling of a particle reduction receiver using continuous flow of perovskite solid and sweep gas in counter-flow configuration has identified issues with managing the oxygen evolved by the solid as well as sweep gas flow rates. Introducing sweep gas quantities necessary for equilibrating the solid with oxygen partial pressures below 10-2 are shown to result in gas phase velocities above the entrainment velocity of 500 um particles. Receiver designs with considerations for gas management are investigated and the results indicate that degrees of reduction corresponding to only oxygen partial pressures of 10-2 bar are attained. Numerical investigation into perovskite thermochemical energy storage indicates that achieving high levels of reduction through sweep gas or vacuum pumping to lower gas phase oxygen partial pressure below 10-2 bar display issues with parasitic energy consumption and gas phase management. Therefore, focus on material development should place a premium on thermal reduction and reduction by shifting oxygen partial pressure between ambient and 10-2 bar. Such a material would enable the development of a system with high solar-to-electric efficiencies and degrees of reduction which are attainable in realistic component geometries.

Acoustic resonance frequency locked photoacoustic spectrometer

DOEpatents

Pilgrim, Jeffrey S.; Bomse, David S.; Silver, Joel A.

2003-09-09

A photoacoustic spectroscopy method and apparatus for maintaining an acoustic source frequency on a sample cell resonance frequency comprising: providing an acoustic source to the sample cell, the acoustic source having a source frequency; repeatedly and continuously sweeping the source frequency across the resonance frequency at a sweep rate; and employing an odd-harmonic of the source frequency sweep rate to maintain the source frequency sweep centered on the resonance frequency.

Influence of vane sweep on rotor-stator interaction noise

NASA Technical Reports Server (NTRS)

Envia, Edmane; Kerschen, Edward J.

1990-01-01

The influence of vane sweep in rotor-stator interaction noise is investigated. In an analytical approach, the interaction of a convected gust representing the rotor viscous wake, with a cascade of cascade of finite span swept airfoils, representing the stator, is analyzed. The analysis is based on the solution of the exact linearized equations of motion. High frequency convected gusts for which noise generation is concentrated near the leading edge of airfoils is considered. In a preliminary study, the problem of an isolated finite span swept airfoil interacting with a convected gust is analyzed. Results indicate that sweep can substantially reduce the farfield noise levels for a single airfoil. Using the single airfoil model, an approximate solution to the problem of noise radiation from a cascade of finite span swept airfoils interacting with a convected gust is derived. A parametric study of noise generated by gust cascade interaction is carried out to assess the effectiveness of vane sweep in reducing rotor-stator interaction noise. The results show that sweep is beneficial in reducing noise levels. Rotor wake twist or circumferential lean substantially influences the effectiveness of vane sweep. The orientation of vane sweep must be chosen to enhance the natural phase lag caused by wake lean, in which case rather small sweep angles substantially reduce the noise levels.

Experimental determination of optimum gutter brush parameters and road sweeping criteria for different types of waste.

PubMed

Abdel-Wahab, Magd M; Wang, Chong; Vanegas-Useche, Libardo V; Parker, Graham A

2011-06-01

The removal ability of gutter brushes for road sweeping for various debris types and different sweeping parameters is studied through experimental tests. The brushing test rig used comprises two commercial gutter brushes, a concrete test bed, and an asphalt test road with a gutter of 0.25 cm width and 10° slope. The brush-surface contact area is determined by sweeping sand on the concrete test bed. Sweeping problems are identified and discussed, and sweeping criteria for the different debris types are suggested. Also, optimum sweeping parameters are proposed for each debris type. In addition, debris removal mechanisms are discussed and analysed. The results indicate that for large heavy debris such as stones and gravel, it is not difficult to achieve large removal forces, because the steel bristles are relatively stiff. Conversely, high removal forces are not needed for particles of millimetre or micron sizes, but bristle curvature has to be appropriate to remove particles from road concavities. Finally, it is found that mud, especially dry mud on a rough surface, is the hardest debris to sweep, requiring a brush with a large tilt angle and a very large penetration to produce large removal forces. Copyright © 2011 Elsevier Ltd. All rights reserved.

Influence of vane sweep on rotor-stator interaction noise

NASA Astrophysics Data System (ADS)

Envia, Edmane; Kerschen, Edward J.

1990-12-01

The influence of vane sweep in rotor-stator interaction noise is investigated. In an analytical approach, the interaction of a convected gust representing the rotor viscous wake, with a cascade of cascade of finite span swept airfoils, representing the stator, is analyzed. The analysis is based on the solution of the exact linearized equations of motion. High frequency convected gusts for which noise generation is concentrated near the leading edge of airfoils is considered. In a preliminary study, the problem of an isolated finite span swept airfoil interacting with a convected gust is analyzed. Results indicate that sweep can substantially reduce the farfield noise levels for a single airfoil. Using the single airfoil model, an approximate solution to the problem of noise radiation from a cascade of finite span swept airfoils interacting with a convected gust is derived. A parametric study of noise generated by gust cascade interaction is carried out to assess the effectiveness of vane sweep in reducing rotor-stator interaction noise. The results show that sweep is beneficial in reducing noise levels. Rotor wake twist or circumferential lean substantially influences the effectiveness of vane sweep. The orientation of vane sweep must be chosen to enhance the natural phase lag caused by wake lean, in which case rather small sweep angles substantially reduce the noise levels.

Visual Acuity and Contrast Sensitivity Development in Children: Sweep Visually Evoked Potential and Psychophysics.

PubMed

Almoqbel, Fahad M; Irving, Elizabeth L; Leat, Susan J

2017-08-01

The purpose of this study was to investigate the development of visual acuity (VA) and contrast sensitivity in children as measured with objective (sweep visually evoked potential) and subjective, psychophysical techniques, including signal detection theory (SDT), which attempts to control for differences in criterion or behavior between adults and children. Furthermore, this study examines the possibility of applying SDT methods with children. Visual acuity and contrast thresholds were measured in 12 children 6 to 7 years old, 10 children 8 to 9 years old, 10 children 10 to 12 years old, and 16 adults. For sweep visually evoked potential measurements, spatial frequency was swept from 1 to 40 cpd to measure VA, and contrast of sine-wave gratings (1 or 8 cpd) was swept from 0.33 to 30% to measure contrast thresholds. For psychophysical measurements, VA and contrast thresholds (1 or 8 cpd) were measured using a temporal two-alternative forced-choice staircase procedure and also with a yes-no SDT procedure. Optotype (logMAR [log of the minimum angle of resolution]) VA was also measured. The results of the various procedures were in agreement showing that there are age-related changes in threshold values and logMAR VA after the age of 6 years and that these visual functions do not become adult-like until the age of 8 to 9 years at the earliest. It was also found that children can participate in SDT procedures and do show differences in criterion compared with adults in psychophysical testing. These findings confirm a slightly later development of VA and contrast sensitivity (8 years or older) and indicate the importance of using SDT or forced-choice procedures in any developmental study to attempt to overcome the effect of criterion in children.

DC Potentials Applied to an End-cap Electrode of a 3-D Ion Trap for Enhanced MSn Functionality

PubMed Central

Prentice, Boone M.; Xu, Wei; Ouyang, Zheng; McLuckey, Scott A.

2010-01-01

The effects of the application of various DC magnitudes and polarities to an end-cap of a 3-D quadrupole ion trap throughout a mass spectrometry experiment were investigated. Application of a monopolar DC field was achieved by applying a DC potential to the exit end-cap electrode, while maintaining the entrance end-cap electrode at ground potential. Control over the monopolar DC magnitude and polarity during time periods associated with ion accumulation, mass analysis, ion isolation, ion/ion reaction, and ion activation can have various desirable effects. Included amongst these are increased ion capture efficiency, increased ion ejection efficiency during mass analysis, effective isolation of ions using lower AC resonance ejection amplitudes, improved temporal control of the overlap of oppositely charged ion populations, and the performance of “broad-band” collision induced dissociation (CID). These results suggest general means to improve the performance of the 3-D ion trap in a variety of mass spectrometry and tandem mass spectrometry experiments. PMID:21927573

Decoy receptor 3: a pleiotropic immunomodulator and biomarker for inflammatory diseases, autoimmune diseases and cancer.

PubMed

Lin, Wan-Wan; Hsieh, Shie-Liang

2011-04-01

Recently, several decoy molecules belonging to tumor necrosis factor receptor superfamily (TNFRSF) have been identified, including decoy receptor 1 (DcR1), decoy receptor 2 (DcR2), and decoy receptor 3 (DcR3). One of the tumor necrosis factor superfamily (TNFSF) members, TNF-related apoptosis-inducing ligand (TRAIL), binds to DcR1 and DcR2, which are membranous receptors with a truncated cytoplasmic domain, thus unable to transduce TRAIL-mediated signaling. In contrast to DcR1 and DcR2, DcR3 is a soluble receptor capable of neutralizing the biological effects of three other TNFSF members: Fas ligand (FasL/TNFSF6/CD95L), LIGHT (TNFSF14) and TNF-like molecule 1A (TL1A/TNFSF15). Since FasL is a potent apoptosis- and inflammation-inducing factor, LIGHT is involved in apoptosis and inflammation, and TL1A is a T cell costimulator and is involved in gut inflammation, DcR3 can be defined as an immunomodulator on the basis of its neutralizing effects on FasL, LIGHT, and TL1A. Initial studies demonstrated that DcR3 expression is elevated in tumors cells; however, later work showed that DcR3 expression is also upregulated in inflammatory diseases, where serum DcR3 levels correlate with disease progression. In addition to its neutralizing effect, DcR3 also acts as an effector molecule to modulate cell function via 'non-decoy' activities. This review focuses on the immunomodulatory effects of DcR3 via 'decoy' and 'non-decoy' functions, and discusses the potential of DcR3 as a biomarker to predict cancer invasion and inflammation progression. We also discuss the possible utility of recombinant DcR3 as a therapeutic agent to control autoimmune diseases, as well as the potential to attenuate tumor progression by inhibiting DcR3 expression. Copyright © 2011 Elsevier Inc. All rights reserved.

A Sweeping Jet Application on a High Reynolds Number Semispan Supercritical Wing Configuration

NASA Technical Reports Server (NTRS)

Jones, Gregory S.; Milholen, William E., II; Chan, David T.; Melton, Latunia; Goodliff, Scott L.; Cagle, C. Mark

2017-01-01

The FAST-MAC circulation control model was modified to test an array of unsteady sweeping-jet actuators at realistic flight Reynolds numbers in the National Transonic Facility at the NASA Langley Research Center. Two types of sweeping jet actuators were fabricated using rapid prototype techniques, and directed over a 15% chord simple-hinged flap. The model was configured for low-speed high-lift testing with flap deflections of 30 deg and 60 deg, and a transonic cruise configuration having a 0 deg flap deflection. For the 30 deg flap high-lift configuration, the sweeping jets achieved comparable lift performance in the separation control regime, while reducing the mass flow by 54% as compared to steady blowing. The sweeping jets however were not effective for the 60 deg flap. For the transonic cruise configuration, the sweeping jets reduced the drag by 3.3% at an off-design condition. The drag reduction for the design lift coefficient for the sweeping jets offer is only half the drag reduction shown for the steady blowing case (6.5%), but accomplished this with a 74% reduction in mass flow.

Using Computational Fluid Dynamics and Experiments to Design Sweeping Jets for High Reynolds Number Cruise Configurations

NASA Technical Reports Server (NTRS)

Jones, Gregory S.; Milholen, William E., II; Fell, Jared S.; Webb, Sandy R.; Cagle, C. Mark

2016-01-01

The application of a sweeping jet actuator to a circulation control system was initiated by a risk reduction series of experiments to optimize the authority of a single sweeping jet actuator. The sweeping jet design was integrated into the existing Fundamental Aerodynamic Subsonic Transonic- Modular Active Control (FAST-MAC) model by replacing the steady blowing system with an array of thirty-nine sweeping jet cartridges. A constant slot height to wing chord ratio was similar to the steady blowing configuration resulting in each actuator having a unique in size for the sweeping jet configuration. While this paper will describe the scaling and optimization of the actuators for future high Reynolds number applications, the major focus of this effort was to target the transonic flight regime by increasing the amplitude authority of the actuator. This was accomplished by modifying the diffuser of the sweeping jet actuator, and this paper highlights twelve different diffuser designs. The experimental portion of this work was completed in the NASA Langley National Transonic Facility.

Determination of the magnetocaloric entropy change by field sweep using a heat flux setup

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

Monteiro, J. C. B., E-mail: jolmiui@gmail.com; Reis, R. D. dos; Mansanares, A. M.

2014-08-18

We report on a simple setup using a heat flux sensor adapted to a Quantum Design Physical Property Measurement System to determine the magnetocaloric entropy change (ΔS). The major differences for the existing setups are the simplicity of this assembly and the ease to obtain the isothermal entropy change either by a field sweep or a temperature sweep process. We discuss the use of these two processes applied to Gd and Gd{sub 5}Ge{sub 2}Si{sub 2} samples. The results are compared to the temperature sweep measurements and they show the advantages of this setup and of the field sweep procedure. Wemore » found a significant reduction of ΔS and on the refrigerating cooling power (RCP) at low field changes in a field sweep process when the sample is not driven to the same initial state for each temperature. We show that the field sweep process without any measuring protocol is the only correct way to experimentally determine ΔS and RCP for a practical regenerative refrigerator.« less

Natural amines inhibit activation of human plasmacytoid dendritic cells through CXCR4 engagement

PubMed Central

Smith, Nikaïa; Pietrancosta, Nicolas; Davidson, Sophia; Dutrieux, Jacques; Chauveau, Lise; Cutolo, Pasquale; Dy, Michel; Scott-Algara, Daniel; Manoury, Bénédicte; Zirafi, Onofrio; McCort-Tranchepain, Isabelle; Durroux, Thierry; Bachelerie, Françoise; Schwartz, Olivier; Münch, Jan; Wack, Andreas; Nisole, Sébastien; Herbeuval, Jean-Philippe

2017-01-01

Plasmacytoid dendritic cells (pDC) are specialized in secretion of type I interferon in response to pathogens. Here we show that natural monoamines and synthetic amines inhibit pDC activation by RNA viruses. Furthermore, a synthetic analogue of histamine reduces type I interferon production in a mouse model of influenza infection. We identify CXC chemokine receptor 4 (CXCR4) as a receptor used by amines to inhibit pDC. Our study establishes a functional link between natural amines and the innate immune system and identifies CXCR4 as a potential ‘on-off' switch of pDC activity with therapeutic potential. PMID:28181493

A new type of single-phase five-level inverter

NASA Astrophysics Data System (ADS)

Xu, Zhi; Li, Shengnan; Qin, Risheng; Zhao, Yanhang

2017-11-01

At present, Neutral Point Clamped (NPC) multilevel inverter is widely applied in new energy field. However, it has some disadvantages including low utilization rate of direct current (DC) voltage source and the unbalance of neutral potential. Therefore, a new single-phase five level inverter is proposed in this paper. It has two stage structure, the former stage is equivalent to three level DC/DC converter, and the back stage uses H bridge to realize inverter. Compared with the original central clamp type inverter, the new five level inverter can improve the utilization of DC voltage, and realize the neutral point potential balance with hysteresis comparator.

Validation of Ionospheric Measurements from the International Space Station (ISS)

NASA Technical Reports Server (NTRS)

Coffey, Victoria; Minow, Joseph; Wright, Kenneth

2009-01-01

The International Space Station orbit provides an ideal platform for in-situ studies of space weather effects on the mid and low-latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) operating on the ISS since Aug 2006, is a suite of plasma instruments: a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-Sweep Langmuir Probe. This instrument package provides a new opportunity for collaborative multi-instrument studies of the F-region ionosphere during both quiet and disturbed periods. This presentation first describes the operational parameters for each of the FPMU probes and shows examples of an intra-instrument validation. We then show comparisons with the plasma density and temperature measurements derived from the TIMED GUVI ultraviolet imager, the Millstone Hill ground based incoherent scatter radar, and DIAS digisondes, Finally we show one of several observations of night-time equatorial density holes demonstrating the capabilities of the probes for monitoring mid and low latitude plasma processes.

In-situ Observations of the Ionospheric F2-Region from the International Space Station

NASA Technical Reports Server (NTRS)

Coffey, Victoria N.; Wright, Kenneth H.; Minow, Joseph I.; Chandler, Michael O.; Parker, Linda N.

2008-01-01

The International Space Station orbit provides an ideal platform for in-situ studies of space weather effects on the mid and low latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) operating on the ISS since Aug 2006, is a suite of plasma instruments: a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). This instrument package provides a new opportunity for collaborative multi-instrument studies of the F-region ionosphere during both quiet and disturbed periods. This presentation first describes the operational parameters for each of the FPMU probes and shows examples of an intra-instrument validation. We then show comparisons with the plasma density and temperature measurements derived from the TIMED GUVI ultraviolet imager, the Millstone Hill ground based incoherent scatter radar, and DIAS digisondes, Finally we show one of several observations of night-time equatorial density holes demonstrating the capabilities of the probes for monitoring mid and low latitude plasma processes.

Removal of road deposited sediments by sweeping and its contribution to highway runoff quality in Korea.

PubMed

Kim, D G; Jeong, K; Ko, S O

2014-01-01

Highway runoff is known to be an important non-point source (NPS), increasing the load of pollutants in receiving water. For reducing NPS pollutants in runoff, removal of road deposited sediment (RDS) by sweeping is considered effective. However, the contribution of sweeping to the improvement of runoff quality has not been clearly and quantitatively demonstrated so far. In this study, a field test was carried out on a section of operating highway in Korea to investigate the effectiveness of sweeping on improving the quality of highway runoff. Results showed that the average reduction in the load of RDS by sweeping was 61.10% with a standard deviation of 1.74%. RDS removal efficiency decreased when the sweeping speed increased from 4-8 to 20 km h(-1), the load decreased from 12.5 to 1.25 g m(-2) and particle size decreased from sand to silt/clay size ranges. Runoff was induced by applying a 15 mm h(-1) artificial rainfall to both swept and non-swept sections. Analysis of runoff quality showed that the event mean concentrations of total suspended solid, biological oxygen demand, chemical oxygen demand, nutrients and most of the heavy metals were reduced by 31-87% after sweeping. In addition, field tests for RDS build-up indicated a sweeping frequency of once every four or five days to prevent re-suspension of RDS. The results of this study suggest that sweeping can be the best management practice for effectively reducing RDS on highways and improving the quality of highway runoff.

Network models of frequency modulated sweep detection.

PubMed

Skorheim, Steven; Razak, Khaleel; Bazhenov, Maxim

2014-01-01

Frequency modulated (FM) sweeps are common in species-specific vocalizations, including human speech. Auditory neurons selective for the direction and rate of frequency change in FM sweeps are present across species, but the synaptic mechanisms underlying such selectivity are only beginning to be understood. Even less is known about mechanisms of experience-dependent changes in FM sweep selectivity. We present three network models of synaptic mechanisms of FM sweep direction and rate selectivity that explains experimental data: (1) The 'facilitation' model contains frequency selective cells operating as coincidence detectors, summing up multiple excitatory inputs with different time delays. (2) The 'duration tuned' model depends on interactions between delayed excitation and early inhibition. The strength of delayed excitation determines the preferred duration. Inhibitory rebound can reinforce the delayed excitation. (3) The 'inhibitory sideband' model uses frequency selective inputs to a network of excitatory and inhibitory cells. The strength and asymmetry of these connections results in neurons responsive to sweeps in a single direction of sufficient sweep rate. Variations of these properties, can explain the diversity of rate-dependent direction selectivity seen across species. We show that the inhibitory sideband model can be trained using spike timing dependent plasticity (STDP) to develop direction selectivity from a non-selective network. These models provide a means to compare the proposed synaptic and spectrotemporal mechanisms of FM sweep processing and can be utilized to explore cellular mechanisms underlying experience- or training-dependent changes in spectrotemporal processing across animal models. Given the analogy between FM sweeps and visual motion, these models can serve a broader function in studying stimulus movement across sensory epithelia.

High speed turboprops for executive aircraft, potential and recent test results

NASA Technical Reports Server (NTRS)

Mikkelson, D. C.; Mitchell, G. A.

1980-01-01

Four high speed propeller models were designed and tested in an 8x6 foot wind tunnel in order to evaluate the potential of advanced propeller technology. Results from these tests show that the combination of: increased blade number, aerodynamically integrated propeller/nacelles, reduced blade thickness, spinner area ruling, and blade sweep are important in achieving high propeller efficiency at the high cruise speeds.

A long-time, high spatiotemporal resolution optical recording system for membrane potential activity via real-time writing to the hard disk.

PubMed

Hirota, Akihiko; Ito, Shin-ichi

2006-06-01

Using real-time hard disk recording, we have developed an optical system for the long-duration detection of changes in membrane potential from 1,020 sites with a high temporal resolution. The signal-to-noise ratio was sufficient for analyzing the spreading pattern of excitatory waves in frog atria in a single sweep.

On the modelling of linear-assisted DC-DC voltage regulators for photovoltaic solar energy systems

NASA Astrophysics Data System (ADS)

Martínez-García, Herminio; García-Vílchez, Encarna

2017-11-01

This paper shows the modelling of linear-assisted or hybrid (linear & switching) DC/DC voltage regulators. In this kind of regulators, an auxiliary linear regulator is used, which objective is to cancel the ripple at the output voltage and provide fast responses for load variations. On the other hand, a switching DC/DC converter, connected in parallel with the linear regulator, allows to supply almost the whole output current demanded by the load. The objective of this topology is to take advantage of the suitable regulation characteristics that series linear voltage regulators have, but almost achieving the high efficiency that switching DC/DC converters provide. Linear-assisted DC/DC regulators are feedback systems with potential instability. Therefore, their modelling is mandatory in order to obtain design guidelines and assure stability of the implemented power supply system.

How Large Asexual Populations Adapt

NASA Astrophysics Data System (ADS)

Desai, Michael

2007-03-01

We often think of beneficial mutations as being rare, and of adaptation as a sequence of selected substitutions: a beneficial mutation occurs, spreads through a population in a selective sweep, then later another beneficial mutation occurs, and so on. This simple picture is the basis for much of our intuition about adaptive evolution, and underlies a number of practical techniques for analyzing sequence data. Yet many large and mostly asexual populations -- including a wide variety of unicellular organisms and viruses -- live in a very different world. In these populations, beneficial mutations are common, and frequently interfere or cooperate with one another as they all attempt to sweep simultaneously. This radically changes the way these populations adapt: rather than an orderly sequence of selective sweeps, evolution is a constant swarm of competing and interfering mutations. I will describe some aspects of these dynamics, including why large asexual populations cannot evolve very quickly and the character of the diversity they maintain. I will explain how this changes our expectations of sequence data, how sex can help a population adapt, and the potential role of ``mutator'' phenotypes with abnormally high mutation rates. Finally, I will discuss comparisons of these predictions with evolution experiments in laboratory yeast populations.

Breakdown of Immune Tolerance in Systemic Lupus Erythematosus by Dendritic Cells

PubMed Central

Reihl, Alec M.

2016-01-01

Dendritic cells (DC) play an important role in the pathogenesis of systemic lupus erythematosus (SLE), an autoimmune disease with multiple tissue manifestations. In this review, we summarize recent studies on the roles of conventional DC and plasmacytoid DC in the development of both murine lupus and human SLE. In the past decade, studies using selective DC depletions have demonstrated critical roles of DC in lupus progression. Comprehensive in vitro and in vivo studies suggest activation of DC by self-antigens in lupus pathogenesis, followed by breakdown of immune tolerance to self. Potential treatment strategies targeting DC have been developed. However, many questions remain regarding the mechanisms by which DC modulate lupus pathogenesis that require further investigations. PMID:27034965

SweeD: likelihood-based detection of selective sweeps in thousands of genomes.

PubMed

Pavlidis, Pavlos; Živkovic, Daniel; Stamatakis, Alexandros; Alachiotis, Nikolaos

2013-09-01

The advent of modern DNA sequencing technology is the driving force in obtaining complete intra-specific genomes that can be used to detect loci that have been subject to positive selection in the recent past. Based on selective sweep theory, beneficial loci can be detected by examining the single nucleotide polymorphism patterns in intraspecific genome alignments. In the last decade, a plethora of algorithms for identifying selective sweeps have been developed. However, the majority of these algorithms have not been designed for analyzing whole-genome data. We present SweeD (Sweep Detector), an open-source tool for the rapid detection of selective sweeps in whole genomes. It analyzes site frequency spectra and represents a substantial extension of the widely used SweepFinder program. The sequential version of SweeD is up to 22 times faster than SweepFinder and, more importantly, is able to analyze thousands of sequences. We also provide a parallel implementation of SweeD for multi-core processors. Furthermore, we implemented a checkpointing mechanism that allows to deploy SweeD on cluster systems with queue execution time restrictions, as well as to resume long-running analyses after processor failures. In addition, the user can specify various demographic models via the command-line to calculate their theoretically expected site frequency spectra. Therefore, (in contrast to SweepFinder) the neutral site frequencies can optionally be directly calculated from a given demographic model. We show that an increase of sample size results in more precise detection of positive selection. Thus, the ability to analyze substantially larger sample sizes by using SweeD leads to more accurate sweep detection. We validate SweeD via simulations and by scanning the first chromosome from the 1000 human Genomes project for selective sweeps. We compare SweeD results with results from a linkage-disequilibrium-based approach and identify common outliers.

Influence of Finite Span and Sweep on Active Flow Control Efficacy

NASA Technical Reports Server (NTRS)

Greenblatt, David; Washburn, Anthony E.

2008-01-01

Active flow control efficacy was investigated by means of leading-edge and flap-shoulder zero mass-flux blowing slots on a semispan wing model that was tested in unswept (standard) and swept configurations. On the standard configuration, stall commenced inboard, but with sweep the wing stalled initially near the tip. On both configurations, leading-edge perturbations increased CL,max and post stall lift, both with and without deflected flaps. Without sweep, the effect of control was approximately uniform across the wing span but remained effective to high angles of attack near the tip; when sweep was introduced a significant effect was noted inboard, but this effect degraded along the span and produced virtually no meaningful lift enhancement near the tip, irrespective of the tip configuration. In the former case, control strengthened the wingtip vortex; in the latter case, a simple semi-empirical model, based on the trajectory or "streamline" of the evolving perturbation, served to explain the observations. In the absence of sweep, control on finite-span flaps did not differ significantly from their nominally twodimensional counterpart. Control from the flap produced expected lift enhancement and CL,max improvements in the absence of sweep, but these improvements degraded with the introduction of sweep.

A new Strategy to Improve Drug Delivery to the Maxillary Sinuses: The Frequency Sweep Acoustic Airflow.

PubMed

El Merhie, Amira; Navarro, Laurent; Delavenne, Xavier; Leclerc, Lara; Pourchez, Jérémie

2016-05-01

Enhancement of intranasal sinus deposition involves nebulization of a drug superimposed by an acoustic airflow. We investigated the impact of fixed frequency versus frequency sweep acoustic airflow on the improvement of aerosolized drug penetration into maxillary sinuses. Fixed frequency and frequency sweep acoustic airflow were generated using a nebulizing system of variable frequency. The effect of sweep cycle and intensity variation was studied on the intranasal sinus deposition. We used a nasal replica created from CT scans using 3D printing. Sodium fluoride and gentamicin were chosen as markers. Studies performed using fixed frequency acoustic airflow showed that each of maxillary sinuses of the nasal replica required specific frequency for the optimal aerosol deposition. Intranasal sinus drug deposition experiments under the effect of the frequency sweep acoustic airflow showed an optimal aerosol deposition into both maxillary sinus of the nasal replica. Studies on the effect of the duration of the sweep cycle showed that the shorter the cycle the better the deposition. We demonstrate the benefit of frequency sweep acoustic airflow on drug deposition into maxillary sinuses. However further in vivo studies have to be conducted since delivery rates cannot be obviously determined from a nasal replica.

Sequential modelling of ICRF wave near RF fields and asymptotic RF sheaths description for AUG ICRF antennas

NASA Astrophysics Data System (ADS)

Jacquot, Jonathan; Tierens, Wouter; Zhang, Wei; Bobkov, Volodymyr; Colas, Laurent; Noterdaeme, Jean-Marie

2017-10-01

A sequence of simulations is performed with RAPLICASOL and SSWICH to compare two AUG ICRF antennas. RAPLICASOL outputs have been used as input to SSWICH-SW for the AUG ICRF antennas. Using parallel electric field maps and the scattering matrix produced by RAPLICASOL, SSWICH-SW, reduced to its asymptotic part, is able to produce a 2D radial/poloidal map of the DC plasma potential accounting for the antenna input settings (total power, power balance, phasing). Two models of antennas are compared: 2-strap antenna vs 3-strap antenna. The 2D DC potential structures are correlated to structures of the parallel electric field map for different phasing and power balance. The overall DC plasma potential on the 3-strap antenna is lower due to better global RF currents compensation. Spatial proximity between regions of high RF electric field and regions where high DC plasma potentials are observed is an important factor for sheath rectification.

Background sounds contribute to spectrotemporal plasticity in primary auditory cortex

PubMed Central

Moucha, Raluca; Pandya, Pritesh K.; Engineer, Navzer D.; Rathbun, Daniel L.

2010-01-01

The mammalian auditory system evolved to extract meaningful information from complex acoustic environments. Spectrotemporal selectivity of auditory neurons provides a potential mechanism to represent natural sounds. Experience-dependent plasticity mechanisms can remodel the spectrotemporal selectivity of neurons in primary auditory cortex (A1). Electrical stimulation of the cholinergic nucleus basalis (NB) enables plasticity in A1 that parallels natural learning and is specific to acoustic features associated with NB activity. In this study, we used NB stimulation to explore how cortical networks reorganize after experience with frequency-modulated (FM) sweeps, and how background stimuli contribute to spectrotemporal plasticity in rat auditory cortex. Pairing an 8–4 kHz FM sweep with NB stimulation 300 times per day for 20 days decreased tone thresholds, frequency selectivity, and response latency of A1 neurons in the region of the tonotopic map activated by the sound. In an attempt to modify neuronal response properties across all of A1 the same NB activation was paired in a second group of rats with five downward FM sweeps, each spanning a different octave. No changes in FM selectivity or receptive field (RF) structure were observed when the neural activation was distributed across the cortical surface. However, the addition of unpaired background sweeps of different rates or direction was sufficient to alter RF characteristics across the tonotopic map in a third group of rats. These results extend earlier observations that cortical neurons can develop stimulus specific plasticity and indicate that background conditions can strongly influence cortical plasticity PMID:15616812

Theory for broadband Noise of Rotor and Stator Cascades with Inhomogeneous Inflow Turbulence Including Effects of Lean and Sweep

NASA Technical Reports Server (NTRS)

Hanson, Donald B.

2001-01-01

The problem of broadband noise generated by turbulence impinging on a downstream blade row is examined from a theoretical viewpoint. Equations are derived for sound power spectra in terms of 3 dimensional wavenumber spectra of the turbulence. Particular attention is given to issues of turbulence inhomogeneity associated with the near field of the rotor and variations through boundary layers. Lean and sweep of the rotor or stator cascade are also handled rigorously with a full derivation of the relevant geometry and definitions of lean and sweep angles. Use of the general theory is illustrated by 2 simple theoretical spectra for homogeneous turbulence. Limited comparisons are made with data from model fans designed by Pratt & Whitney, Allison, and Boeing. Parametric studies for stator noise are presented showing trends with Mach number, vane count, turbulence scale and intensity, lean, and sweep. Two conventions are presented to define lean and sweep. In the "cascade system" lean is a rotation out of its plane and sweep is a rotation of the airfoil in its plane. In the "duct system" lean is the leading edge angle viewing the fan from the front (along the fan axis) and sweep is the angle viewing the fan from the side (,perpendicular to the axis). It is shown that the governing parameter is sweep in the plane of the airfoil (which reduces the chordwise component of Mach number). Lean (out of the plane of the airfoil) has little effect. Rotor noise predictions are compared with duct turbulence/rotor interaction noise data from Boeing and variations, including blade tip sweep and turbulence axial and transverse scales are explored.

Rheological Studies of PMMA–PVC Based Polymer Blend Electrolytes with LiTFSI as Doping Salt

PubMed Central

Liew, Chiam–Wen; Durairaj, R.; Ramesh, S.

2014-01-01

In this research, two systems are studied. In the first system, the ratio of poly (methyl methacrylate) (PMMA) and poly (vinyl chloride) (PVC) is varied, whereas in the second system, the composition of PMMA–PVC polymer blends is varied with dopant salt, lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) with a fixed ratio of 70 wt% of PMMA to 30 wt% of PVC. Oscillation tests such as amplitude sweep and frequency sweep are discussed in order to study the viscoelastic properties of samples. Elastic properties are much higher than viscous properties within the range in the amplitude sweep and oscillatory shear sweep studies. The crossover of and is absent. Linear viscoelastic (LVE) range was further determined in order to perform the frequency sweep. However, the absence of viscous behavior in the frequency sweep indicates the solid-like characteristic within the frequency regime. The viscosity of all samples is found to decrease as shear rate increases. PMID:25051241

Verification of Bwo Model of Vlf Chorus Generation Using Magion 5 Data

NASA Astrophysics Data System (ADS)

Titova, E. E.; Kozelov, B. V.; Jiricek, F.; Smilauer, J.; Demekhov, A. G.; Trakhtengerts, V. Yu.

We present a detailed study of chorus emissions in the magnetosphere detected on- board the Magion 5, when the satellite was at low magnetic latitudes. We determine the frequency sweep rate and the periods of electromagnetic VLF chorus emissions. These results are considered within the concept of the backward wave oscillator (BWO) regime of chorus generation. Comparison of the frequency sweep rate of chorus el- ements shows: (i) There is a correlation between the frequency sweep rates and the chorus amplitudes. The frequency sweep rate increases with chorus amplitude in ac- cord with expectations from the BWO model. (ii) The chorus growth rate, estimated from the frequency sweep rate, is in accord with that inferred from the BWO gener- ation mechanism. (iii) The BWO regime of chorus generation ensures the observed decrease in the frequency sweep rate of the chorus elements with increasing L shell. We also discuss the relationship between the observed periods of chorus elements with the predictions following from the BWO model of chorus generation.

Use of solar cell in electrokinetic remediation of cadmium-contaminated soil.

PubMed

Yuan, Songhu; Zheng, Zhonghua; Chen, Jing; Lu, Xiaohua

2009-03-15

This preliminary study used a solar cell, instead of direct current (DC) power supply, to generate electric field for electrokinetic (EK) remediation of cadmium-contaminated soil. Three EK tests were conducted and compared; one was conducted on a cloudy and rainy day with solar cell, one was conducted on a sunny day with solar cell and another was conducted periodically with DC power supply. It was found that the output potential of solar cell depended on daytime and was influenced by weather conditions; the applied potential in soil was affected by the output potential and weather conditions, and the current achieved by solar cell was comparable with that achieved by DC power supply. Solar cell could be used to drive the electromigration of cadmium in contaminated soil, and removal efficiency achieved by solar cell was comparable with that achieved by DC power supply. Compared with traditional DC power supply, using solar cell as power supply for EK remediation can greatly reduce energy expenditure. This study provided an alternative to improve the EK soil remediation and expanded the use of solar cell in environmental remediation.

On-line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy.

PubMed

Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

2003-03-01

This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping-micellar electrokinetic chromatography (MEKC) was used for the initial on-line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on-line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography-mass spectrometry (GC-MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC-MS in such analyses.

Enhancement of the conductivity detection signal in capillary electrophoresis systems using neutral cyclodextrins as sweeping agents.

PubMed

Boublík, Milan; Riesová, Martina; Dubský, Pavel; Gaš, Bohuslav

2018-06-01

Conductivity detection is a universal detection technique often encountered in electrophoretic separation systems, especially in modern chip-electrophoresis based devices. On the other hand, it is sparsely combined with another contemporary trend of enhancing limits of detection by means of various preconcentration strategies. This can be attributed to the fact that a preconcentration experimental setup usually brings about disturbances in a conductivity baseline. Sweeping with a neutral sweeping agent seems a good candidate for overcoming this problem. A neutral sweeping agent does not hinder the conductivity detection while a charged analyte may preconcentrate on its boundary due to a decrease in its effective mobility. This study investigates such sweeping systems theoretically, by means of computer simulations, and experimentally. A formula is provided for the reliable estimation of the preconcentration factor. Additionally, it is demonstrated that the conductivity signal can significantly benefit from slowing down the analyte and thus the overall signal enhancement can easily overweight amplification caused solely by the sweeping process. The overall enhancement factor can be deduced a priori from the linearized theory of electrophoresis implemented in the PeakMaster freeware. Sweeping by neutral cyclodextrin is demonstrated on an amplification of a conductivity signal of flurbiprofen in a real drug sample. Finally, a possible formation of unexpected system peaks in systems with a neutral sweeping agent is revealed by the computer simulation and confirmed experimentally. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vitro assessment of fiber sweeping angle during Q-switched 532-nm laser tissue ablation

NASA Astrophysics Data System (ADS)

Rajabhandharaks, Danop; Kang, Hyun Wook; Ko, Woo Jin; Stinson, Douglas; Choi, Benjamin

2011-03-01

Photoselective vaporization of the prostate (PVP) has been widely used to treat benign prostatic hyperplasia (BPH). It is well regarded as a safe and minimally invasive procedure and an alternative to the gold standard transurethral resection of the prostate (TURP). Despite of its greatness, as well aware of, the operative procedure time during the PVP is still prolonged. Such attempts have been tried out in order to shorten the operative time and increase its efficacy. However, scientific study to investigate techniques used during the PVP is still lacking. The objective of this study is to investigate how sweeping angle might affect the PVP performance. Porcine kidneys acquired from a local grocery store were used (N=140). A Q-switched 532-nm GreenLight XPSTM (American Medical Systems, Inc., MN, USA), together with 750- μm core MoXyTM fiber, was set to have power levels of 120 W and 180 W. Treatment speed and sweeping speed were fixed at 2 mm/s and 0.5 sweep/s, respectively. Sweeping angles were varied from 0 (no sweeping motion) to 120 degree. Ablation rate, depth, and coagulation zone were measured and quantified. Tissue ablation rate was peaked at 15 and 30 degree for both 120- and 180-W power levels and dramatically decreased beyond 60 degree. At 180 W, ablation rate increased 20% at 30 degree compared to 0 degree. This study demonstrated that ablation rate could be maximized and was contingent upon sweeping angle.

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.

Monitoring environmental quality at the landscape scale

Treesearch

Robert V. O' Neill; Carolyn T. Hunsaker; K. Bruce Jones; Kurt H. Riitters; James D. Wickham; Paul M. Schwartz; Iris A. Goodman; Barbara L. Jackson; William S. Baillargeon

1997-01-01

Over the past century, technological advances have greatly improved the standard of living in the United States. But these same advances have caused sweeping environmental changes, often unforeseen and potentially irreparable. Ethical stewardship of the environment requires that society monitor and assess environmental changes at the national scale with a view toward...

Plasmacytoid pre-dendritic cells (pDC): from molecular pathways to function and disease association.

PubMed

Alculumbre, Solana; Raieli, Salvatore; Hoffmann, Caroline; Chelbi, Rabie; Danlos, François-Xavier; Soumelis, Vassili

2018-02-19

Plasmacytoid pre-dendritic cells (pDC) are a specialized DC population with a great potential to produce large amounts of type I interferon (IFN). pDC are involved in the initiation of antiviral immune responses through their interaction with innate and adaptive immune cell populations. In a context-dependent manner, pDC activation can induce their differentiation into mature DC able to induce both T cell activation or tolerance. In this review, we described pDC functions during immune responses and their implication in the clearance or pathogenicity of human diseases during infection, autoimmunity, allergy and cancer. We discuss recent advances in the field of pDC biology and their implication for future studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Electrical and electrochemical studies on sodium ion-based gel polymer electrolytes

NASA Astrophysics Data System (ADS)

Isa, K. B. Md; Othman, L.; Hambali, D.; Osman, Z.

2017-09-01

Gel polymer electrolytes (GPEs) have captured great attention because of their unique properties such as good mechanical stability, high flexibility and high conductivity approachable to that of the liquid electrolytes. In this work, we have prepared sodium ion conducting gel polymer electrolyte (GPE) films consisting of polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) as a polymer host using the solution casting technique. Sodium trifluoromethane- sulfonate (NaCF3SO3) was used as an ionic salt and the mixture of ethylene carbonate (EC) and propylene carbonate (PC) as a plasticizing solvent. Impedance spectroscopy measurements were carried out to determine the ionic conductivity of the GPE films. The sample containing 20 wt.% of NaCF3SO3 salt exhibits the highest room temperature ionic conductivity of 2.50 × 10-3 S cm-1. The conductivity of the GPE films was found to depend on the salt concentration that added to the films. The ionic and cationic transference numbers of GPE films were estimated by DC polarization and the combination of AC and DC polarization method, respectively. The results had shown that both ionic and cationic transference numbers are consistent with the conductivity studies. The electrochemical stability of the GPE films was tested using linear sweep voltammetry (LSV) and the value of working voltage range appears to be high enough to be used as an electrolyte in sodium batteries. The cyclic voltammetry (CV) studies confirmed the sodium ion conduction in the GPE films.

3D cine magnetic resonance imaging of rat lung ARDS using gradient-modulated SWIFT with retrospective respiratory gating

NASA Astrophysics Data System (ADS)

Kobayashi, Naoharu; Lei, Jianxun; Utecht, Lynn; Garwood, Michael; Ingbar, David H.; Bhargava, Maneesh

2015-03-01

SWeep Imaging with Fourier Transformation (SWIFT) with gradient modulation and DC navigator retrospective gating is introduced as a 3D cine magnetic resonance imaging (MRI) method for the lung. In anesthetized normal rats, the quasi-simultaneous excitation and acquisition in SWIFT enabled extremely high sensitivity to the fast-decaying parenchymal signals (TE=~4 μs), which are invisible with conventional MRI techniques. Respiratory motion information was extracted from DC navigator signals and the SWIFT data were reconstructed to 3D cine images with 16 respiratory phases. To test this technique's capabilities, rats exposed to > 95% O2 for 60 hours for induction of acute respiratory distress syndrome (ARDS), were imaged and compared with normal rat lungs (N=7 and 5 for ARDS and normal groups, respectively). SWIFT images showed lung tissue density differences along the gravity direction. In the cine SWIFT images, a parenchymal signal drop at the inhalation phase was consistently observed for both normal and ARDS rats due to lung inflation (i.e. decrease of the proton density), but the drop was less for ARDS rats. Depending on the respiratory phase and lung region, the lungs from the ARDS rats showed 1-24% higher parenchymal signal intensities relative to the normal rat lungs, likely due to accumulated extravascular water (EVLW). Those results demonstrate that SWIFT has high enough sensitivity for detecting the lung proton density changes due to gravity, different phases of respiration and accumulation of EVLW in the rat ARDS lungs.

Study on electrostatic and electromagnetic probes operated in ceramic and metallic depositing plasmas

NASA Astrophysics Data System (ADS)

Styrnoll, T.; Bienholz, S.; Lapke, M.; Awakowicz, P.

2014-04-01

This paper discusses plasma probe diagnostics, namely the multipole resonance probe (MRP) and Langmuir probe (LP), operated in depositing plasmas. The aim of this work is to show that the combination of both probes provides stable and robust measurements and clear determination of plasma parameters for metallic and ceramic coating processes. The probes use different approaches to determine plasma parameters, e.g. electron density ne and electron temperature Te. The LP is a well-established plasma diagnostic, and its applicability in technological plasmas is well documented. The LP is a dc probe that performs a voltage sweep and analyses the measured current, which makes it insensitive against conductive metallic coating. However, once the LP is dielectrically coated with a ceramic film, its functionality is constricted. In contrast, the MRP was recently presented as a monitoring tool, which is insensitive to coating with dielectric ceramics. It is a new plasma diagnostic based on the concept of active plasma resonance spectroscopy, which uses the universal characteristic of all plasmas to resonate on or near the electron plasma frequency. The MRP emits a frequency sweep and the absorption of the signal, the |S11| parameter, is analysed. Since the MRP concept is based on electromagnetic waves, which are able to transmit dielectrics, it is insensitive to dielectric coatings. But once the MRP is metallized with a thin conductive film, no undisturbed RF-signal can be emitted into the plasma, which leads to falsified plasma parameter. In order to compare both systems, during metallic or dielectric coating, the probes are operated in a magnetron CCP, which is equipped with a titanium target. We present measurements in metallic and dielectric coating processes with both probes and elaborate advantages and problems of each probe operated in each coating environment.

Electrochemistry of cations in diopsidic melt - Determining diffusion rates and redox potentials from voltammetric curves

NASA Technical Reports Server (NTRS)

Colson, Russell O.; Haskin, Larry A.; Crane, Daniel

1990-01-01

Results are presented on determinations of reduction potentials and their temperature dependence of selected ions in diopsidic melt, by using linear sweep voltammetry. Diffusion coefficients were measured for cations of Eu, Mn, Cr, and In. Enthalpies and entropies of reduction were determined for the cations V(V), Cr(3+), Mn(2+), Mn(3+), Fe(2+), Cu(2+), Mo(VI), Sn(IV), and Eu(3+). Reduction potentials were used to study the structural state of cations in the melt.

On the maintenance of genetic variation and adaptation to environmental change: considerations from population genomics in fishes.

PubMed

Bernatchez, L

2016-12-01

The first goal of this paper was to overview modern approaches to local adaptation, with a focus on the use of population genomics data to detect signals of natural selection in fishes. Several mechanisms are discussed that may enhance the maintenance of genetic variation and evolutionary potential, which have been overlooked and should be considered in future theoretical development and predictive models: the prevalence of soft sweeps, polygenic basis of adaptation, balancing selection and transient polymorphisms, parallel evolution, as well as epigenetic variation. Research on fish population genomics has provided ample evidence for local adaptation at the genome level. Pervasive adaptive evolution, however, seems to almost never involve the fixation of beneficial alleles. Instead, adaptation apparently proceeds most commonly by soft sweeps entailing shifts in frequencies of alleles being shared between differentially adapted populations. One obvious factor contributing to the maintenance of standing genetic variation in the face of selective pressures is that adaptive phenotypic traits are most often highly polygenic, and consequently the response to selection should derive mostly from allelic co-variances among causative loci rather than pronounced allele frequency changes. Balancing selection in its various forms may also play an important role in maintaining adaptive genetic variation and the evolutionary potential of species to cope with environmental change. A large body of literature on fishes also shows that repeated evolution of adaptive phenotypes is a ubiquitous evolutionary phenomenon that seems to occur most often via different genetic solutions, further adding to the potential options of species to cope with a changing environment. Moreover, a paradox is emerging from recent fish studies whereby populations of highly reduced effective population sizes and impoverished genetic diversity can apparently retain their adaptive potential in some circumstances. Although more empirical support is needed, several recent studies suggest that epigenetic variation could account for this apparent paradox. Therefore, epigenetic variation should be fully integrated with considerations pertaining to role of soft sweeps, polygenic and balancing selection, as well as repeated adaptation involving different genetic basis towards improving models predicting the evolutionary potential of species to cope with a changing world. © 2016 The Fisheries Society of the British Isles.

Limited Evidence for Classic Selective Sweeps in African Populations

PubMed Central

Granka, Julie M.; Henn, Brenna M.; Gignoux, Christopher R.; Kidd, Jeffrey M.; Bustamante, Carlos D.; Feldman, Marcus W.

2012-01-01

While hundreds of loci have been identified as reflecting strong-positive selection in human populations, connections between candidate loci and specific selective pressures often remain obscure. This study investigates broader patterns of selection in African populations, which are underrepresented despite their potential to offer key insights into human adaptation. We scan for hard selective sweeps using several haplotype and allele-frequency statistics with a data set of nearly 500,000 genome-wide single-nucleotide polymorphisms in 12 highly diverged African populations that span a range of environments and subsistence strategies. We find that positive selection does not appear to be a strong determinant of allele-frequency differentiation among these African populations. Haplotype statistics do identify putatively selected regions that are shared across African populations. However, as assessed by extensive simulations, patterns of haplotype sharing between African populations follow neutral expectations and suggest that tails of the empirical distributions contain false-positive signals. After highlighting several genomic regions where positive selection can be inferred with higher confidence, we use a novel method to identify biological functions enriched among populations’ empirical tail genomic windows, such as immune response in agricultural groups. In general, however, it seems that current methods for selection scans are poorly suited to populations that, like the African populations in this study, are affected by ascertainment bias and have low levels of linkage disequilibrium, possibly old selective sweeps, and potentially reduced phasing accuracy. Additionally, population history can confound the interpretation of selection statistics, suggesting that greater care is needed in attributing broad genetic patterns to human adaptation. PMID:22960214

Optimization of the separation of lysergic acid diethylamide in urine by a sweeping technique using micellar electrokinetic chromatography.

PubMed

Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

2002-07-25

The separation and on-line concentrations of lysergic acid diethylamide (LSD), iso-lysergic acid diethylamide (iso-LSD) and lysergic acid N,N-methylpropylamide (LAMPA) in human urine were investigated by capillary electrophoresis-fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as an anionic surfactant. A number of parameters such as buffer pH, SDS concentration, Brij-30 concentration and the content of organic solvent used in separation, were optimized. The techniques of sweeping-micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were used for determining on-line concentrations. The advantages and disadvantages of this procedure with respect to sensitivity, precision and simplicity are discussed and compared. Copyright 2002 Elsevier Science BV.

Characterization of wavelength-swept active mode locking fiber laser based on reflective semiconductor optical amplifier

NASA Astrophysics Data System (ADS)

Lee, Hwi Don; Lee, Ju Han; Yung Jeong, Myung; Kim, Chang-Seok

2011-07-01

The static and dynamic characteristics of a wavelength-swept active mode locking (AML) fiber laser are presented in both the time-region and wavelength-region. This paper shows experimentally that the linewidth of a laser spectrum and the bandwidth of the sweeping wavelength are dependent directly on the length and dispersion of the fiber cavity as well as the modulation frequency and sweeping rate under the mode-locking condition. To achieve a narrower linewidth, a longer length and higher dispersion of the fiber cavity as well as a higher order mode locking condition are required simultaneously. For a broader bandwidth, a lower order of the mode locking condition is required using a lower modulation frequency. The dynamic sweeping performance is also analyzed experimentally to determine its applicability to optical coherence tomography imaging. It is shown that the maximum sweeping rate can be improved by the increased free spectral range from the shorter length of the fiber cavity. A reflective semiconductor optical amplifier (RSOA) was used to enhance the modulation and dispersion efficiency. Overall a triangular electrical signal can be used instead of the sinusoidal signal to sweep the lasing wavelength at a high sweeping rate due to the lack of mechanical restrictions in the wavelength sweeping mechanism.

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.

Epigenetic Regulation of Chermokine Expression in Prostate Cancer

DTIC Science & Technology

2008-12-01

Chemotactic potential of CXCL14 for human DC Recently, we demonstrated that CXCL14 and CXCL14-positive HNSCC ( Head and Neck Squamouse Cell...insights into the functional interaction between DC and neoplastic cells, we proposed to analyze the effects of PCa on the chemotaxis of human DC in...vitro and in vivo. Our Specific Aims were: 1. Characterize chemotactic activity of CXCL14 towards human DC in vitro. 2. Examine whether restoration of

Effects of Sweep Angle on the Boundary-Layer Stability Characteristics of an Untapered Wing at Low Speeds

NASA Technical Reports Server (NTRS)

Boltz, Frederick W.; Kenyon, George C.; Allen, Clyde Q.

1960-01-01

An investigation was conducted in the Ames 12-Foot Low-Turbulence Pressure Tunnel to determine the effects of sweep on the boundary-layer stability characteristics of an untapered variable-sweep wing having an NACA 64(2)A015 section normal to the leading edge. Pressure distribution and transition were measured on the wing at low speeds at sweep angles of 0, 10, 20, 30, 40, and 50 deg. and at angles of attack from -3 to 3 deg. The investigation also included flow-visualization studies on the surface at sweep angles from 0 to 50 deg. and total pressure surveys in the boundary layer at a sweep angle of 30 deg. for angles of attack from -12 to 0 deg. It was found that sweep caused premature transition on the wing under certain conditions. This effect resulted from the formation of vortices in the boundary layer when a critical combination of sweep angle, pressure gradient, and stream Reynolds number was attained. A useful parameter in indicating the combined effect of these flow variables on vortex formation and on beginning transition is the crossflow Reynolds number. The critical values of crossflow Reynolds number for vortex formation found in this investigation range from about 135 to 190 and are in good agreement with those reported in previous investigations. The values of crossflow Reynolds number for beginning transitions were found to be between 190 and 260. For each condition (i.e., development of vortices and initiation of transition at a given location) the lower values in the specified ranges were obtained with a light coating of flow-visualization material on the surface. A method is presented for the rapid computation of crossflow Reynolds number on any swept surface for which the pressure distribution is known. From calculations based on this method, it was found that the maximum values of crossflow Reynolds number are attained under conditions of a strong pressure gradient and at a sweep angle of about 50 deg. Due to the primary dependence on pressure gradient, effects of sweep in causing premature transition are generally first encountered on the lower surfaces of wings operating at positive angles of attack.

DC Rocks! Using Place-Based Learning to Introduce Washington DC's K-12 Students to the Geosciences

NASA Astrophysics Data System (ADS)

Mayberry, G. C.; Mattietti, G. K.

2017-12-01

The Washington DC area has interesting geology and a multitude of agencies that deal with the geosciences, yet K-12 public school students in DC, most of whom are minorities, have limited exposure to the geosciences. Geoscience agencies in the DC area have a unique opportunity to address this by introducing the geosciences to local students who otherwise may not have such an opportunity, by highlighting the geology in the students' "backyard," and by leveraging partnerships among DC-based geoscience-related agencies. The USGS and George Mason University are developing a project called DC Rocks, which will give DC's students an exciting introduction into the world of geoscience with place-based learning opportunities that will make geoscience relevant to their lives and their futures. Both the need in DC and the potential for lasting impact are great; the geosciences have the lowest racial diversity of all the science, technology, engineering, and math (STEM) fields, 89% of students in DC public schools are minorities, and there is no dedicated geoscience curriculum in DC. DC Rocks aims to give these students early exposure to the earth sciences, and encourage them to consider careers in the profession. DC Rocks will work with partner agencies to apply several methods that are recommended by researchers to increase the participation of minority students in the geosciences, including providing profoundly positive experiences that spark interest in the geosciences (Levine et al., 2007); increasing students' sense of belonging in the geosciences (Huntoon, et al, 2016); and place-based teaching practices that emphasize the study of local sites (Semken, 2005), such as DC's Rock Creek Park. DC Rocks will apply these methods by coordinating local geoscientists and resources to provide real-world examples of the geosciences' impact on students' lives. Through the DC Rocks website, educators will be able to request geoscience-related resources such as class presentations by local scientists and curricula, and students will be able to access information about geoscience-related opportunities in DC such as field trips. DC Rocks has the potential to encourage minority students to consider higher education in the geosciences by exposing them to the field early on and ultimately these students may pursue geoscience careers.

A Review of Microgrid Architectures and Control Strategy

NASA Astrophysics Data System (ADS)

Jadav, Krishnarajsinh A.; Karkar, Hitesh M.; Trivedi, I. N.

2017-12-01

In this paper microgrid architecture and various converters control strategies are reviewed. Microgrid is defined as interconnected network of distributed energy resources, loads and energy storage systems. This emerging concept realizes the potential of distributed generators. AC microgrid interconnects various AC distributed generators like wind turbine and DC distributed generators like PV, fuel cell using inverter. While in DC microgrid output of an AC distributed generator must be converted to DC using rectifiers and DC distributed generator can be directly interconnected. Hybrid microgrid is the solution to avoid this multiple reverse conversions AC-DC-AC and DC-AC-DC that occur in the individual AC-DC microgrid. In hybrid microgrid all AC distributed generators will be connected in AC microgrid and DC distributed generators will be connected in DC microgrid. Interlinking converter is used for power balance in both microgrids, which transfer power from one microgrid to other if any microgrid is overloaded. At the end, review of interlinking converter control strategies is presented.

You're a What? Chimney Sweep

ERIC Educational Resources Information Center

Green, Kathleen

2010-01-01

In this article, the author talks about a chimney sweep--also called a "sweep"--which inspects chimneys as well as cleans them. Some inspections are for a specific purpose, such as home appraisal, but most precede cleaning. Chimney cleaning requires a certain level of dexterity, because the job includes a lot of climbing, squatting, kneeling, and…

SWEEP: Sciencing with Watersheds, Environmental Education and Partnerships. Instructor's Guide to Implementation and Summer Institute Participant Notebook.

ERIC Educational Resources Information Center

Bainer, Deb; Barron, Pat; Cantrell, Diane

Sciencing with Watersheds, Environmental Education, and Partnerships (SWEEP) is a professional development program designed to help elementary teachers improve the way they teach science using partnerships among teachers and resource professionals. SWEEP follows a thematic approach using watersheds as the core concept of an integrated elementary…

The Effect of Leading-Edge Sweep and Surface Inclination on the Hypersonic Flow Field Over a Blunt Flat Plate

NASA Technical Reports Server (NTRS)

Creager, Marcus O.

1959-01-01

An investigation of the effects of variation of leading-edge sweep and surface inclination on the flow over blunt flat plates was conducted at Mach numbers of 4 and 5.7 at free-stream Reynolds numbers per inch of 6,600 and 20,000, respectively. Surface pressures were measured on a flat plate blunted by a semicylindrical leading edge over a range of sweep angles from 0 deg to 60 deg and a range of surface inclinations from -10 deg to +10 deg. The surface pressures were predicted within an average error of +/- 8 percent by a combination of blast-wave and boundary-layer theory extended herein to include effects of sweep and surface inclination. This combination applied equally well to similar data of other investigations. The local Reynolds number per inch was found to be lower than the free-stream Reynolds number per inch. The reduction in local Reynolds number was mitigated by increasing the sweep of the leading edge. Boundary-layer thickness and shock-wave shape were changed little by the sweep of the leading edge.

Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography.

PubMed

Fang, Ching; Liu, Ju-Tsung; Chou, Shiu-Huey; Lin, Cheng-Huang

2003-03-01

The separation and on-line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on-line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were applied; the optimum on-line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; approximately 1/10 to the value of LD(50)). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.

S{sub 2}SA preconditioning for the S{sub n} equations with strictly non negative spatial discretization

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

Bruss, D. E.; Morel, J. E.; Ragusa, J. C.

2013-07-01

Preconditioners based upon sweeps and diffusion-synthetic acceleration have been constructed and applied to the zeroth and first spatial moments of the 1-D S{sub n} transport equation using a strictly non negative nonlinear spatial closure. Linear and nonlinear preconditioners have been analyzed. The effectiveness of various combinations of these preconditioners are compared. In one dimension, nonlinear sweep preconditioning is shown to be superior to linear sweep preconditioning, and DSA preconditioning using nonlinear sweeps in conjunction with a linear diffusion equation is found to be essentially equivalent to nonlinear sweeps in conjunction with a nonlinear diffusion equation. The ability to use amore » linear diffusion equation has important implications for preconditioning the S{sub n} equations with a strictly non negative spatial discretization in multiple dimensions. (authors)« less

Autonomous Planning and Replanning for Mine-Sweeping Unmanned Underwater Vehicles

NASA Technical Reports Server (NTRS)

Gaines, Daniel M.

2010-01-01

This software generates high-quality plans for carrying out mine-sweeping activities under resource constraints. The autonomous planning and replanning system for unmanned underwater vehicles (UUVs) takes as input a set of prioritized mine-sweep regions, and a specification of available UUV resources including available battery energy, data storage, and time available for accomplishing the mission. Mine-sweep areas vary in location, size of area to be swept, and importance of the region. The planner also works with a model of the UUV, as well as a model of the power consumption of the vehicle when idle and when moving.

EpiSweep: Computationally Driven Reengineering of Therapeutic Proteins to Reduce Immunogenicity While Maintaining Function.

PubMed

Choi, Yoonjoo; Verma, Deeptak; Griswold, Karl E; Bailey-Kellogg, Chris

2017-01-01

Therapeutic proteins are yielding ever more advanced and efficacious new drugs, but the biological origins of these highly effective therapeutics render them subject to immune surveillance within the patient's body. When recognized by the immune system as a foreign agent, protein drugs elicit a coordinated response that can manifest a range of clinical complications including rapid drug clearance, loss of functionality and efficacy, delayed infusion-like allergic reactions, more serious anaphylactic shock, and even induced auto-immunity. It is thus often necessary to deimmunize an exogenous protein in order to enable its clinical application; critically, the deimmunization process must also maintain the desired therapeutic activity.To meet the growing need for effective, efficient, and broadly applicable protein deimmunization technologies, we have developed the EpiSweep suite of protein design algorithms. EpiSweep seamlessly integrates computational prediction of immunogenic T cell epitopes with sequence- or structure-based assessment of the impacts of mutations on protein stability and function, in order to select combinations of mutations that make Pareto optimal trade-offs between the competing goals of low immunogenicity and high-level function. The methods are applicable both to the design of individual functionally deimmunized variants as well as the design of combinatorial libraries enriched in functionally deimmunized variants. After validating EpiSweep in a series of retrospective case studies providing comparisons to conventional approaches to T cell epitope deletion, we have experimentally demonstrated it to be highly effective in prospective application to deimmunization of a number of different therapeutic candidates. We conclude that our broadly applicable computational protein design algorithms guide the engineer towards the most promising deimmunized therapeutic candidates, and thereby have the potential to accelerate development of new protein drugs by shortening time frames and improving hit rates.

Reduction in symptomatic malaria prevalence through proactive community treatment in rural Senegal.

PubMed

Linn, Annē M; Ndiaye, Youssoupha; Hennessee, Ian; Gaye, Seynabou; Linn, Patrick; Nordstrom, Karin; McLaughlin, Matt

2015-11-01

We piloted a community-based proactive malaria case detection model in rural Senegal to evaluate whether this model can increase testing and treatment and reduce prevalence of symptomatic malaria in target communities. Home care providers conducted weekly sweeps of every household in their village throughout the transmission season to identify patients with symptoms of malaria, perform rapid diagnostic tests (RDT) on symptomatic patients and provide treatment for positive cases. The model was implemented in 15 villages from July to November 2013, the high transmission season. Fifteen comparison villages were chosen from those implementing Senegal's original, passive model of community case management of malaria. Three sweeps were conducted in the comparison villages to compare prevalence of symptomatic malaria using difference in differences analysis. At baseline, prevalence of symptomatic malaria confirmed by RDT for all symptomatic individuals found during sweeps was similar in both sets of villages (P = 0.79). At end line, prevalence was 16 times higher in the comparison villages than in the intervention villages (P = 0.003). Adjusting for potential confounders, the intervention was associated with a 30-fold reduction in odds of symptomatic malaria in the intervention villages (AOR = 0.033; 95% CI: 0.017, 0.065). Treatment seeking also increased in the intervention villages, with 57% of consultations by home care providers conducted between sweeps through routine community case management. This pilot study suggests that community-based proactive case detection reduces symptomatic malaria prevalence, likely through more timely case management and improved care seeking behaviour. A randomised controlled trial is needed to further evaluate the impact of this model. © 2015 John Wiley & Sons Ltd.

EpiSweep: Computationally-driven Reengineering of Therapeutic Proteins to Reduce immunogenicity while Maintaining Function

PubMed Central

Choi, Yoonjoo; Verma, Deeptak; Griswold, Karl E.; Bailey-Kellogg, Chris

2016-01-01

Therapeutic proteins are yielding ever more advanced and efficacious new drugs, but the biological origins of these highly effective therapeutics renders them subject to immune surveillance within the patient’s body. When recognized by the immune system as a foreign agent, protein drugs elicit a coordinated response that can manifest a range of clinical complications including rapid drug clearance, loss of functionality and efficacy, delayed infusion-like allergic reactions, more serious anaphylactic shock, and even induced auto-immunity. It is thus often necessary to deimmunize an exogenous protein in order to enable its clinical application; critically, the deimmunization process must also maintain the desired therapeutic activity. To meet the growing need for effective, efficient, and broadly applicable protein deimmunization technologies, we have developed the EpiSweep suite of protein design algorithms. EpiSweep seamlessly integrates computational prediction of immunogenic T cell epitopes with sequence- or structure- based assessment of the impacts of mutations on protein stability and function, in order to select combinations of mutations that make Pareto optimal trade-offs between the competing goals of low immunogenicity and high-level function. The methods are applicable both to the design of individual functionally deimmunized variants as well as the design of combinatorial libraries enriched in functionally deimmunized variants. After validating EpiSweep in a series of retrospective case studies providing comparisons to conventional approaches to T cell epitope deletion, we have experimentally demonstrated it to be highly effective in prospective application to deimmunization of a number of different therapeutic candidates. We conclude that our broadly applicable computational protein design algorithms guide the engineer towards the most promising deimmunized therapeutic candidates, and thereby have the potential to accelerate development of new protein drugs by shortening time frames and improving hit rates. PMID:27914063

Automated multi-slice extracellular and patch-clamp experiments using the WinLTP data acquisition system with automated perfusion control

PubMed Central

Anderson, William W.; Fitzjohn, Stephen M.; Collingridge, Graham L.

2012-01-01

WinLTP is a data acquisition program for studying long-term potentiation (LTP) and other aspects of synaptic function. Earlier versions of WinLTP (J. Neurosci. Methods, 162:346–356, 2007) provided automated electrical stimulation and data acquisition capable of running nearly an entire synaptic plasticity experiment, with the primary exception that perfusion solutions had to be changed manually. This automated stimulation and acquisition was done by using ‘Sweep’, ‘Loop’ and ‘Delay’ events to build scripts using the ‘Protocol Builder’. However, this did not allow automatic changing of many solutions while running multiple slice experiments, or solution changing when this had to be performed rapidly and with accurate timing during patch-clamp experiments. We report here the addition of automated perfusion control to WinLTP. First, perfusion change between sweeps is enabled by adding the ‘Perfuse’ event to Protocol Builder scripting and is used in slice experiments. Second, fast perfusion changes during as well as between sweeps is enabled by using the Perfuse event in the protocol scripts to control changes between sweeps, and also by changing digital or analog output during a sweep and is used for single cell single-line perfusion patch-clamp experiments. The addition of stepper control of tube placement allows dual- or triple-line perfusion patch-clamp experiments for up to 48 solutions. The ability to automate perfusion changes and fully integrate them with the already automated stimulation and data acquisition goes a long way toward complete automation of multi-slice extracellularly recorded and single cell patch-clamp experiments. PMID:22524994

Validation of SWEEP for contrasting agricultural land use types in the Tarim Basin

USDA-ARS?s Scientific Manuscript database

In order to aid in identifying land management practices with the potential to control soil erosion, models such as the Wind Erosion Prediction System (WEPS) have been developed to assess soil erosion. The objective of this study was to test the performance of the WEPS erosion submodel (the Single-e...

Acoustically swept rotor. [helicopter noise reduction

NASA Technical Reports Server (NTRS)

Schmitz, F. H.; Boxwell, D. A.; Vause, R. (Inventor)

1979-01-01

Impulsive noise reduction is provided in a rotor blade by acoustically sweeping the chord line from root to tip so that the acoustic radiation resulting from the summation of potential singularities used to model the flow about the blade tend to cancel for all times at an observation point in the acoustic far field.

Pulse Voltammetry in Single Cells Using Platinum Microelectrodes

DTIC Science & Technology

1991-11-22

E. and the range for Ed in multiple pulse voltammetry can be chosen from examination of voltammograms obtained by cyclic voltammetry or lin-ir sweep ... voltametry [3,13]. As pointed out by Sinru et al. [14) the potential and time of each pulse has a direct effect on the nature of the voltammetry

Development of Nitrogen Sensor for Determination of PN(2) in Body Tissues.

DTIC Science & Technology

1982-07-01

3) The progress of the reduction reaction (1) was followed by voltammetry. A single anodic potential sweep , starting from the open circuit...Graphite Electrode The progressive attachment of [Ru(NH3 ) 5 H2 0] +2 to PVP-coated graphite electrodes was observed by cyclic voltametry as an

Electrochemical behavior of lead alloys in sulfuric and phosphoric acid solutions

NASA Astrophysics Data System (ADS)

Paleska, I.; Pruszkowska-Drachal, R.; Kotowski, J.; Dziudzi, A.; Milewski, J. D.; Kopczyk, M.; Czerwiński, A.

The electrochemical behavior of lead, lead-antimony, and lead-calcium-aluminium-tin alloys has been studied in solutions containing various concentrations of sulfuric and phosphoric acids. The dependence of these electrode processes on some experimental conditions (mainly sweep rate and potential range) has been studied. The measurements were performed using a cyclic voltammetry technique. The study and the analysis of the morphology of alloys have been performed using a scanning electron microscope (SEM). Cyclic voltammograms of the lead-antimony alloy electrodes, similarly to pure lead electrode, also show the "anodic excursion" peak under some experimental conditions. Well defined current waves, corresponding to the oxidation and reduction processes of Sb, are observed, if the alloy surface is freshly abraded. The oxidation of antimony starts at potentials at which the formation of PbO takes place. The peak current of Sb oxidation reaction decreases during successive cycles, suggesting that Sb dissolves from the alloy surface during the first CV sweeps. Another explanation for this effect might be the formation of a PbSO 4 selective membrane.

In-Situ F2-Region Plasma Density and Temperature Measurements from the International Space Station

NASA Technical Reports Server (NTRS)

Coffey, Victoria; Wright, Kenneth; Minow, Joseph

2008-01-01

The International Space Station orbit provides an ideal platform for in-situ studies of space weather effects on the mid and low latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) operating on the ISS since Aug 2006. is a suite of plasma instruments: a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). This instrument package provides a new opportunity lor collaborative multi-instrument studies of the F-region ionosphere during both quiet and disturbed periods. This presentation first describes the operational parameters for each of the FPMU probes and shOWS examples of an intra-instrument validation. We then show comparisons with the plasma density and temperature measurements derived from the TIMED GUVI ultraviolet imager, the Millstone Hill ground based incoherent scatter radar, and DIAS digisondes, Finally we show one of several observations of night-time equatorial density holes demonstrating the capabilities of the probes lor monitoring mid and low latitude plasma processes.

Matched Behavioral and Neural Adaptations for Low Sound Level Echolocation in a Gleaning Bat, Antrozous pallidus.

PubMed

Measor, Kevin R; Leavell, Brian C; Brewton, Dustin H; Rumschlag, Jeffrey; Barber, Jesse R; Razak, Khaleel A

2017-01-01

In active sensing, animals make motor adjustments to match sensory inputs to specialized neural circuitry. Here, we describe an active sensing system for sound level processing. The pallid bat uses downward frequency-modulated (FM) sweeps as echolocation calls for general orientation and obstacle avoidance. The bat's auditory cortex contains a region selective for these FM sweeps (FM sweep-selective region, FMSR). We show that the vast majority of FMSR neurons are sensitive and strongly selective for relatively low levels (30-60 dB SPL). Behavioral testing shows that when a flying bat approaches a target, it reduces output call levels to keep echo levels between ∼30 and 55 dB SPL. Thus, the pallid bat behaviorally matches echo levels to an optimized neural representation of sound levels. FMSR neurons are more selective for sound levels of FM sweeps than tones, suggesting that across-frequency integration enhances level tuning. Level-dependent timing of high-frequency sideband inhibition in the receptive field shapes increased level selectivity for FM sweeps. Together with previous studies, these data indicate that the same receptive field properties shape multiple filters (sweep direction, rate, and level) for FM sweeps, a sound common in multiple vocalizations, including human speech. The matched behavioral and neural adaptations for low-intensity echolocation in the pallid bat will facilitate foraging with reduced probability of acoustic detection by prey.

Matched Behavioral and Neural Adaptations for Low Sound Level Echolocation in a Gleaning Bat, Antrozous pallidus

PubMed Central

Measor, Kevin R.; Leavell, Brian C.; Brewton, Dustin H.; Rumschlag, Jeffrey; Barber, Jesse R.

2017-01-01

Abstract In active sensing, animals make motor adjustments to match sensory inputs to specialized neural circuitry. Here, we describe an active sensing system for sound level processing. The pallid bat uses downward frequency-modulated (FM) sweeps as echolocation calls for general orientation and obstacle avoidance. The bat’s auditory cortex contains a region selective for these FM sweeps (FM sweep-selective region, FMSR). We show that the vast majority of FMSR neurons are sensitive and strongly selective for relatively low levels (30-60 dB SPL). Behavioral testing shows that when a flying bat approaches a target, it reduces output call levels to keep echo levels between ∼30 and 55 dB SPL. Thus, the pallid bat behaviorally matches echo levels to an optimized neural representation of sound levels. FMSR neurons are more selective for sound levels of FM sweeps than tones, suggesting that across-frequency integration enhances level tuning. Level-dependent timing of high-frequency sideband inhibition in the receptive field shapes increased level selectivity for FM sweeps. Together with previous studies, these data indicate that the same receptive field properties shape multiple filters (sweep direction, rate, and level) for FM sweeps, a sound common in multiple vocalizations, including human speech. The matched behavioral and neural adaptations for low-intensity echolocation in the pallid bat will facilitate foraging with reduced probability of acoustic detection by prey. PMID:28275715

Effect of top gate potential on bias-stress for dual gate amorphous indium-gallium-zinc-oxide thin film transistor

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

Chun, Minkyu; Um, Jae Gwang; Park, Min Sang

We report the abnormal behavior of the threshold voltage (V{sub TH}) shift under positive bias Temperature stress (PBTS) and negative bias temperature stress (NBTS) at top/bottom gate in dual gate amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs). It is found that the PBTS at top gate shows negative transfer shift and NBTS shows positive transfer shift for both top and bottom gate sweep. The shift of bottom/top gate sweep is dominated by top gate bias (V{sub TG}), while bottom gate bias (V{sub BG}) is less effect than V{sub TG}. The X-ray photoelectron spectroscopy (XPS) depth profile provides the evidence of Inmore » metal diffusion to the top SiO{sub 2}/a-IGZO and also the existence of large amount of In{sup +} under positive top gate bias around top interfaces, thus negative transfer shift is observed. On the other hand, the formation of OH{sup −} at top interfaces under the stress of negative top gate bias shows negative transfer shift. The domination of V{sub TG} both on bottom/top gate sweep after PBTS/NBTS is obviously occurred due to thin active layer.« less

Compliance-Free, Digital SET and Analog RESET Synaptic Characteristics of Sub-Tantalum Oxide Based Neuromorphic Device.

PubMed

Abbas, Yawar; Jeon, Yu-Rim; Sokolov, Andrey Sergeevich; Kim, Sohyeon; Ku, Boncheol; Choi, Changhwan

2018-01-19

A two terminal semiconducting device like a memristor is indispensable to emulate the function of synapse in the working memory. The analog switching characteristics of memristor play a vital role in the emulation of biological synapses. The application of consecutive voltage sweeps or pulses (action potentials) changes the conductivity of the memristor which is considered as the fundamental cause of the synaptic plasticity. In this study, a neuromorphic device using an in-situ growth of sub-tantalum oxide switching layer is fabricated, which exhibits the digital SET and analog RESET switching with an electroforming process without any compliance current (compliance free). The process of electroforming and SET is observed at the positive sweeps of +2.4 V and +0.86 V, respectively, while multilevel RESET is observed with the consecutive negative sweeps in the range of 0 V to -1.2 V. The movement of oxygen vacancies and gradual change in the anatomy of the filament is attributed to digital SET and analog RESET switching characteristics. For the Ti/Ta 2 O 3-x /Pt neuromorphic device, the Ti top and Pt bottom electrodes are considered as counterparts of the pre-synaptic input terminal and a post-synaptic output terminal, respectively.

Wind turbine rotor blade with in-plane sweep and devices using same, and methods for making same

DOEpatents

Wetzel, Kyle Kristopher

2008-03-18

A wind turbine includes a rotor having a hub and at least one blade having a torsionally rigid root, an inboard section, and an outboard section. The inboard section has a forward sweep relative to an elastic axis of the blade and the outboard section has an aft sweep.

Tissue-specific differentiation of a circulating CCR9- pDC-like common dendritic cell precursor.

PubMed

Schlitzer, Andreas; Heiseke, Alexander F; Einwächter, Henrik; Reindl, Wolfgang; Schiemann, Matthias; Manta, Calin-Petru; See, Peter; Niess, Jan-Hendrik; Suter, Tobias; Ginhoux, Florent; Krug, Anne B

2012-06-21

The ontogenic relationship between the common dendritic cell (DC) progenitor (CDP), the committed conventional DC precursor (pre-cDC), and cDC subpopulations in lymphoid and nonlymphoid tissues has been largely unraveled. In contrast, the sequential steps of plasmacytoid DC (pDC) development are less defined, and it is unknown at which developmental stage and location final commitment to the pDC lineage occurs. Here we show that CCR9(-) pDCs from murine BM which enter the circulation and peripheral tissues have a common DC precursor function in vivo in the steady state, in contrast to CCR9(+) pDCs which are terminally differentiated. On adoptive transfer, the fate of CCR9(-) pDC-like precursors is governed by the tissues they enter. In the BM and liver, most transferred CCR9(-) pDC-like precursors differentiate into CCR9(+) pDCs, whereas in peripheral lymphoid organs, lung, and intestine, they additionally give rise to cDCs. CCR9(-) pDC-like precursors which are distinct from pre-cDCs can be generated from the CDP. Thus, CCR9(-) pDC-like cells are novel CDP-derived circulating DC precursors with pDC and cDC potential. Their final differentiation into functionally distinct pDCs and cDCs depends on tissue-specific factors allowing adaptation to local requirements under homeostatic conditions.

Parametric Experimental Study of the Formation of Glaze Ice Shapes on Swept Wings

NASA Technical Reports Server (NTRS)

Vargas, Mario; Reshotko, Eli

1999-01-01

An experiment was conducted to study the effect of velocity and sweep angle on the critical distance in ice accretion formation on swept wings at glaze ice conditions. The critical distance is defined as the distance from the attachment line to the beginning of the zone where roughness elements develop into glaze ice feathers. Icing runs were performed on a NACA 00 1 2 swept wing tip at velocities of 75, 100, 150, and 200 miles per hour. At each velocity and tunnel condition, the sweep angle was changed from 0 deg to 45 deg at 5 deg increments. Casting data, ice shape tracings, and close-up photographic data were obtained. The results showed that at given velocity and tunnel conditions, as the sweep angle is increased from 0 deg to 25 deg the critical distance slowly decreases. As the sweep angle is increased past 25 deg, the critical distance starts decreasing more rapidly. For 75 and 100 mph it reaches a value of 0 millimeters at 35 deg. For 150 and 200 mph it reaches a value of 0 millimeters at 40 deg. On the ice accretion, as the sweep angle is increased from 0 deg to 25 deg, the extent of the attachment line zone slowly decreases. In the glaze ice feathers zone, the angle that the preferred direction of growth of the feathers makes with respect to the attachment line direction increases. But overall, the ice accretions remain similar to the 0 deg sweep angle case. As the sweep angle is increased above 25 deg, the extent of the attachment line zone decreases rapidly and complete scallops form at 35 deg sweep angle for 75 and 100 mph, and at 40 deg for 150 and 200 mph.

A selective sweep of >8 Mb on chromosome 26 in the Boxer genome.

PubMed

Quilez, Javier; Short, Andrea D; Martínez, Verónica; Kennedy, Lorna J; Ollier, William; Sanchez, Armand; Altet, Laura; Francino, Olga

2011-07-01

Modern dog breeds display traits that are either breed-specific or shared by a few breeds as a result of genetic bottlenecks during the breed creation process and artificial selection for breed standards. Selective sweeps in the genome result from strong selection and can be detected as a reduction or elimination of polymorphism in a given region of the genome. Extended regions of homozygosity, indicative of selective sweeps, were identified in a genome-wide scan dataset of 25 Boxers from the United Kingdom genotyped at ~20,000 single-nucleotide polymorphisms (SNPs). These regions were further examined in a second dataset of Boxers collected from a different geographical location and genotyped using higher density SNP arrays (~170,000 SNPs). A selective sweep previously associated with canine brachycephaly was detected on chromosome 1. A novel selective sweep of over 8 Mb was observed on chromosome 26 in Boxer and for a shorter region in English and French bulldogs. It was absent in 171 samples from eight other dog breeds and 7 Iberian wolf samples. A region of extended increased heterozygosity on chromosome 9 overlapped with a previously reported copy number variant (CNV) which was polymorphic in multiple dog breeds. A selective sweep of more than 8 Mb on chromosome 26 was identified in the Boxer genome. This sweep is likely caused by strong artificial selection for a trait of interest and could have inadvertently led to undesired health implications for this breed. Furthermore, we provide supporting evidence for two previously described regions: a selective sweep on chromosome 1 associated with canine brachycephaly and a CNV on chromosome 9 polymorphic in multiple dog breeds.

Combustion systems and power plants incorporating parallel carbon dioxide capture and sweep-based membrane separation units to remove carbon dioxide from combustion gases

DOEpatents

Wijmans, Johannes G [Menlo Park, CA; Merkel, Timothy C [Menlo Park, CA; Baker, Richard W [Palo Alto, CA

2011-10-11

Disclosed herein are combustion systems and power plants that incorporate sweep-based membrane separation units to remove carbon dioxide from combustion gases. In its most basic embodiment, the invention is a combustion system that includes three discrete units: a combustion unit, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In a preferred embodiment, the invention is a power plant including a combustion unit, a power generation system, a carbon dioxide capture unit, and a sweep-based membrane separation unit. In both of these embodiments, the carbon dioxide capture unit and the sweep-based membrane separation unit are configured to be operated in parallel, by which we mean that each unit is adapted to receive exhaust gases from the combustion unit without such gases first passing through the other unit.

Mannosyl Glycodendritic Structure Inhibits DC-SIGN-Mediated Ebola Virus Infection in cis and in trans

PubMed Central

Lasala, Fátima; Arce, Eva; Otero, Joaquín R.; Rojo, Javier; Delgado, Rafael

2003-01-01

We have designed a glycodendritic structure, BH30sucMan, that blocks the interaction between dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN) and Ebola virus (EBOV) envelope. BH30sucMan inhibits DC-SIGN-mediated EBOV infection at nanomolar concentrations. BH30sucMan may counteract important steps of the infective process of EBOV and, potentially, of microorganisms shown to exploit DC-SIGN for cell entry and infection. PMID:14638512

Examining the speed-flow-delay paradox in the Washington, DC region : potential impacts of reduced traffic on congestion delay and potential for reductions in discretionary travel during peak periods.

DOT National Transportation Integrated Search

2008-12-01

Traffic congestion in the Washington, DC area, especially congestion on our freeways, costs our residents every day : in terms of wasted time, fuel, and increased air pollution. Highway studies have determined that once traffic volumes : exceed the c...

Stable-Carbon Isotope Ratios for Sourcing the Nerve-Agent Precursor Methylphosphonic Dichloride and Its Products

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

Moran, James J.; Fraga, Carlos G.; Nims, Megan K.

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13C analysis to be used as a fingerprintingmore » tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. Here, we demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.« less

Stable-Carbon Isotope Ratios for Sourcing the Nerve-Agent Precursor Methylphosphonic Dichloride and Its Products

DOE PAGES

Moran, James J.; Fraga, Carlos G.; Nims, Megan K.

2018-04-01

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13C analysis to be used as a fingerprintingmore » tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. Here, we demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.« less

Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products.

PubMed

Moran, James J; Fraga, Carlos G; Nims, Megan K

2018-08-15

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. DC is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ 13 C analysis to be used as a fingerprinting tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a significant isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool. Copyright © 2018. Published by Elsevier B.V.

Wind turbine rotor blade with in-plane sweep and devices using the same, and methods for making the same

DOEpatents

Wetzel, Kyle Kristopher

2014-06-24

A wind turbine includes a rotor having a hub and at least one blade having a torsionally rigid root, an inboard section, and an outboard section. The inboard section has a forward sweep relative to an elastic axis of the blade and the outboard section has an aft sweep.

76 FR 34788 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-14

... routing fee applies as noted in the table. The Primary Sweep Order (PSO) is a market or limit order that... a PSO designation should be marketable. Non-marketable orders will function as regular limit orders... Primary Sweep Order (PSO) is a market or limit order that sweeps the NYSE Arca Book and routes any...

Application of a hybrid computer to sweep frequency data processing

NASA Technical Reports Server (NTRS)

Milner, E. J.; Bruton, W. M.

1973-01-01

A hybrid computer program is presented which can process as many as 10 channels of sweep frequency data simultaneously. The program needs only the sine sweep signal used to drive the system, and its correponding quadrature component, to process the data. It can handle a maximum frequency range of 0.5 to 500 hertz. Magnitude and phase are calculated at logarithmically spaced points covering the frequency range of interest. When the sweep is completed, these results are stored in digital form. Thus, a tabular listing and/or a plot of any processed data channel or the transfer function relating any two of them is immediately available.

The Role of Interfacial Potential in Adsorbate Bonding: Electrode Potential-Dependent Infrared Spectra for Saturated CO Adlayers on Pt(110) and Related Electrochemical Surfaces in Varying Solvent Environments

DTIC Science & Technology

1992-05-01

as supporting electrolytes were recrystallized from methanol, water and ethanol , and water, respectively, and dried under vacuum at 110°C. Electrode...under these conditions 8,17 (vide infra). All measurements were performed at room temperature , 23±1*C. RESULTS AND DISCUSSION The experimental strategy...of interferometer scans during a suitably slow (2 mV s- ) positive-going potential sweep. For solvents containing traces of water, electrooxidative

MPACT Subgroup Self-Shielding Efficiency Improvements

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

Stimpson, Shane; Liu, Yuxuan; Collins, Benjamin S.

Recent developments to improve the efficiency of the MOC solvers in MPACT have yielded effective kernels that loop over several energy groups at once, rather that looping over one group at a time. These kernels have produced roughly a 2x speedup on the MOC sweeping time during eigenvalue calculation. However, the self-shielding subgroup calculation had not been reevaluated to take advantage of these new kernels, which typically requires substantial solve time. The improvements covered in this report start by integrating the multigroup kernel concepts into the subgroup calculation, which are then used as the basis for further extensions. The nextmore » improvement that is covered is what is currently being termed as “Lumped Parameter MOC”. Because the subgroup calculation is a purely fixed source problem and multiple sweeps are performed only to update the boundary angular fluxes, the sweep procedure can be condensed to allow for the instantaneous propagation of the flux across a spatial domain, without the need to sweep along all segments in a ray. Once the boundary angular fluxes are considered to be converged, an additional sweep that will tally the scalar flux is completed. The last improvement that is investigated is the possible reduction of the number of azimuthal angles per octant in the shielding sweep. Typically 16 azimuthal angles per octant are used for self-shielding and eigenvalue calculations, but it is possible that the self-shielding sweeps are less sensitive to the number of angles than the full eigenvalue calculation.« less

A novel methodology for determining low-cost fine particulate matter street sweeping routes.

PubMed

Blazquez, Carola A; Beghelli, Alejandra; Meneses, Veronica P

2012-02-01

This paper addresses the problem of low-cost PM10 (particulate matter with aerodynamic diameter < 10 microm) street sweeping route. In order to do so, only a subset of the streets of the urban area to be swept is selected for sweeping, based on their PM10 emission factor values. Subsequently, a low-cost route that visits each street in the set is computed. Unlike related problems of waste collection where streets must be visited once (Chinese or Rural Postman Problem, respectively), in this case, the sweeping vehicle route must visit each selected street exactly as many times as its number of street sides, since the vehicle can sweep only one street side at a time. Additionally, the route must comply with traffic flow and turn constraints. A novel transformation of the original arc routing problem into a node routing problem is proposed in this paper. This is accomplished by building a graph that represents the area to sweep in such a way that the problem can be solved by applying any known solution to the Traveling Salesman Problem (TSP). As a way of illustration, the proposed method was applied to the northeast area of the Municipality of Santiago (Chile). Results show that the proposed methodology achieved up to 37% savings in kilometers traveled by the sweeping vehicle when compared to the solution obtained by solving the TSP problem with Geographic Information Systems (GIS)--aware tools.

Efficient sweep buffering in swept source optical coherence tomography using a fast optical switch

PubMed Central

Dhalla, Al-Hafeez; Shia, Kevin; Izatt, Joseph A.

2012-01-01

We describe a novel buffering technique for increasing the A-scan rate of swept source optical coherence tomography (SSOCT) systems employing low duty cycle swept source lasers. This technique differs from previously reported buffering techniques in that it employs a fast optical switch, capable of switching in 60 ns, instead of a fused fiber coupler at the end of the buffering stage, and is therefore appreciably more power efficient. The use of the switch also eliminates patient exposure to light that is not used for imaging that occurs at the end of the laser sweep, thereby increasing the system sensitivity. We also describe how careful management of polarization can remove undesirable artifacts due to polarization mode dispersion. In addition, we demonstrate how numerical compensation techniques can be used to modify the signal from a Mach-Zehnder interferometer (MZI) clock obtained from the original sweep to recalibrate the buffered sweep, thereby reducing the complexity of systems employing lasers with integrated MZI clocks. Combining these methods, we constructed an SSOCT system employing an Axsun technologies laser with a sweep rate of 100kHz and 6dB imaging range of 5.5mm. The sweep rate was doubled with sweep buffering to 200 kHz, and the imaging depth was extended to 9 mm using coherence revival. We demonstrated the feasibility of this system by acquiring images of the anterior segments and retinas of healthy human volunteers. PMID:23243559

Efficient sweep buffering in swept source optical coherence tomography using a fast optical switch.

PubMed

Dhalla, Al-Hafeez; Shia, Kevin; Izatt, Joseph A

2012-12-01

We describe a novel buffering technique for increasing the A-scan rate of swept source optical coherence tomography (SSOCT) systems employing low duty cycle swept source lasers. This technique differs from previously reported buffering techniques in that it employs a fast optical switch, capable of switching in 60 ns, instead of a fused fiber coupler at the end of the buffering stage, and is therefore appreciably more power efficient. The use of the switch also eliminates patient exposure to light that is not used for imaging that occurs at the end of the laser sweep, thereby increasing the system sensitivity. We also describe how careful management of polarization can remove undesirable artifacts due to polarization mode dispersion. In addition, we demonstrate how numerical compensation techniques can be used to modify the signal from a Mach-Zehnder interferometer (MZI) clock obtained from the original sweep to recalibrate the buffered sweep, thereby reducing the complexity of systems employing lasers with integrated MZI clocks. Combining these methods, we constructed an SSOCT system employing an Axsun technologies laser with a sweep rate of 100kHz and 6dB imaging range of 5.5mm. The sweep rate was doubled with sweep buffering to 200 kHz, and the imaging depth was extended to 9 mm using coherence revival. We demonstrated the feasibility of this system by acquiring images of the anterior segments and retinas of healthy human volunteers.

Formation of Fused-Ring 2′-Deoxycytidine Adducts from 1-Chloro-3-buten-2-one, an in Vitro 1,3-Butadiene Metabolite, under in Vitro Physiological Conditions

PubMed Central

Sun, Liang; Pelah, Avishay; Zhang, Dong-Ping; Zhong, Yu-Fang; An, Jing; Yu, Ying-Xin; Zhang, Xin-Yu; Elfarra, Adnan A.

2013-01-01

1-Chloro-3-buten-2-one (CBO) is a potential metabolite of 1,3-butadiene (BD), a carcinogenic air pollutant. CBO is a bifunctional alkylating agent that readily reacts with glutathione (GSH) to form mono-GSH and di-GSH adducts. Recently, CBO and its precursor 1-chloro-2-hydroxy-3-butene (CHB) were found to be cytotoxic and genotoxic in human liver cells in culture with CBO being approximately 100-fold more potent than CHB. In the present study, CBO was shown to react readily with 2′-deoxycytidine (dC) under in vitro physiological conditions (pH 7.4, 37 °C) to form four dC adducts with the CBO moieties forming fused rings with the N3 and N4 atoms of dC. The four products were structurally characterized as 2-hydroxy-2-hydroxymethyl-7-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,3,4-tetrahy dro-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-1 and dC-2, a pair of diastereomers), 4-chloromethyl-4-hydroxy-7-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,3,4-tetrahydr o-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-3), and 2-chloromethyl-2-hydroxy-7-(2-deoxy-β-D-erythro-pentofuranosyl)-1,2,3,4-tetrahydr o-6-oxo-6H,7H-pyrimido[1,6-a]pyrimidin-5-ium (dC-4). Interestingly, dC-1 and dC-2 were stable under our experimental conditions (pH 7.4, 37 °C, 6 h) and existed in equilibrium as indicated by HPLC analysis, whereas dC-3 and dC-4 were labile with the half-lives being 3.0 ± 0.36 and 1.7 ± 0.06 h, respectively. Decomposition of dC-4 produced both dC-1 and dC-2, whereas acid hydrolysis of dC-1/dC-2 and dC-4 in 1 M HCl at 100 °C for 30 min yielded the deribosylated adducts dC-1H/dC-2H and dC-4H, respectively. Because fused-ring dC adducts of other chemicals are mutagenic, the characterized CBO-dC adducts could be mutagenic and play a role in the cytotoxicity and genotoxicity of CBO and its precursors, CHB and BD. The CBO-dC adducts may also be used as standards to characterize CBO-DNA adducts and to develop potential biomarkers for CBO formation in vivo. PMID:24020501

Ex vivo generation of dendritic cells from cryopreserved, post-induction chemotherapy, mobilized leukapheresis from pediatric patients with medulloblastoma.

PubMed

Nair, Smita K; Driscoll, Timothy; Boczkowski, David; Schmittling, Robert; Reynolds, Renee; Johnson, Laura A; Grant, Gerald; Fuchs, Herbert; Bigner, Darell D; Sampson, John H; Gururangan, Sridharan; Mitchell, Duane A

2015-10-01

Generation of patient-derived, autologous dendritic cells (DCs) is a critical component of cancer immunotherapy with ex vivo-generated, tumor antigen-loaded DCs. An important factor in the ability to generate DCs is the potential impact of prior therapies on DC phenotype and function. We investigated the ability to generate DCs using cells harvested from pediatric patients with medulloblastoma for potential evaluation of DC-RNA based vaccination approach in this patient population. Cells harvested from medulloblastoma patient leukapheresis following induction chemotherapy and granulocyte colony stimulating factor mobilization were cryopreserved prior to use in DC generation. DCs were generated from the adherent CD14+ monocytes using standard procedures and analyzed for cell recovery, phenotype and function. To summarize, 4 out of 5 patients (80%) had sufficient monocyte recovery to permit DC generation, and we were able to generate DCs from 3 out of these 4 patient samples (75%). Overall, we successfully generated DCs that met phenotypic requisites for DC-based cancer therapy from 3 out of 5 (60%) patient samples and met both phenotypic and functional requisites from 2 out of 5 (40%) patient samples. This study highlights the potential to generate functional DCs for further clinical treatments from refractory patients that have been heavily pretreated with myelosuppressive chemotherapy. Here we demonstrate the utility of evaluating the effect of the currently employed standard-of-care therapies on the ex vivo generation of DCs for DC-based clinical studies in cancer patients.

Design and analysis for detection monitoring of forest health

Treesearch

F. A. Roesch

1995-01-01

An analysis procedure is proposed for the sample design of the Forest Health Monitoring Program (FHM) in the United States. The procedure is intended to provide increased sensitivity to localized but potentially important changes in forest health by explicitly accounting for the spatial relationships between plots in the FHM design. After a series of median sweeps...

High Speed Computational Ghost Imaging via Spatial Sweeping

NASA Astrophysics Data System (ADS)

Wang, Yuwang; Liu, Yang; Suo, Jinli; Situ, Guohai; Qiao, Chang; Dai, Qionghai

2017-03-01

Computational ghost imaging (CGI) achieves single-pixel imaging by using a Spatial Light Modulator (SLM) to generate structured illuminations for spatially resolved information encoding. The imaging speed of CGI is limited by the modulation frequency of available SLMs, and sets back its practical applications. This paper proposes to bypass this limitation by trading off SLM’s redundant spatial resolution for multiplication of the modulation frequency. Specifically, a pair of galvanic mirrors sweeping across the high resolution SLM multiply the modulation frequency within the spatial resolution gap between SLM and the final reconstruction. A proof-of-principle setup with two middle end galvanic mirrors achieves ghost imaging as fast as 42 Hz at 80 × 80-pixel resolution, 5 times faster than state-of-the-arts, and holds potential for one magnitude further multiplication by hardware upgrading. Our approach brings a significant improvement in the imaging speed of ghost imaging and pushes ghost imaging towards practical applications.

Activated carbon derived from melaleuca barks for outstanding high-rate supercapacitors

NASA Astrophysics Data System (ADS)

Luo, Qiu-Ping; Huang, Liang; Gao, Xiang; Cheng, Yongliang; Yao, Bin; Hu, Zhimi; Wan, Jun; Xiao, Xu; Zhou, Jun

2015-07-01

Activated carbon (AC) was prepared via carbonizing melaleuca bark in an argon atmosphere at 600 °C followed with KOH activation for high-rate supercapacitors. This AC electrode has a high capacitance of 233 F g-1 at a scan rate of 2 mV s-1 and an excellent rate capability of ˜80% when increasing the sweep rate from 2 to 500 mV s-1. The symmetric supercapacitor assembled by the above electrode can deliver a high energy density of 4.2 Wh kg-1 with a power density of 1500 W kg-1 when operated in the voltage range of 0-1 V in 1 M H2SO4 aqueous electrolyte while maintaining great cycling stability (less than 5% capacitance loss after 10 000 cycles at sweep rate of 100 mV s-1). All the outstanding electrochemical performances make this AC electrode a promising candidate for potential energy storage application.

Characterization of the Electron Energy Distribution Function in a Penning Discharge

NASA Astrophysics Data System (ADS)

Skoutnev, Valentin; Dourbal, Paul; Raitses, Yevgeny

2017-10-01

Slow and fast sweeping Langmuir probe diagnostics were implemented to measure the electron energy distribution function (EEDF) in a cross-field Penning discharge undergoing rotating spoke phenomenon. The EEDF was measured using the Druyvesteyn method. Rotating spoke occurs in a variety of ExB devices and is characterized primarily by azimuthal light, density, and potential fluctuations on the order of a few kHz, but is theoretically still not well understood. Characterization of a time-resolved EEDF of the spoke would be important for understanding physical mechanisms responsible for the spoke and its effects on Penning discharges, Hall thrusters, sputtering magnetrons, and other ExB devices. In this work, preliminary results of measurements of the EEDF using slow and fast Langmuir probes that sweep below and above the fundamental spoke frequency will be discussed. This work was supported by the Air Force Office of Scientific Research (AFOSR).

Electrochemical characterization and electrode kinetics for antimony electrodeposition from its oxychloride solution in the presence of tartaric acid

NASA Astrophysics Data System (ADS)

Majidzade, Vusala Asim; Guliyev, Parvin Heydar; Aliyev, Akif Shikhan; Elrouby, Mahmoud; Tagiyev, Dilgam Babir

2017-05-01

This work is devoted to investigate the process of the electrochemical deposition of antimony from antimony oxychloride solution in the presence of tartaric acid in aqueous media. The kinetics and the mechanism of the electrodeposition process at the electrode surface are studied and proposed by the aid of cyclic, linear sweep voltammetric and chronoamperometric characterization methods. It is found that, the process is affected by the presence of tartaric acid and some factors during the electro-reduction process. The results also show that, the temperature, the potential sweep rate and the concentration of antimony have a great influence on the achievement of the electrodeposition process. Some important parameters are calculated such as, the activation energy of the electrochemical reaction, the diffusion coefficient and the number of saturated nucleation sites. The electrodeposited film is examined using X-ray diffraction, scanning electron microscopy and Energy Dispersive Spectroscopy.

Parametric analysis of swept-wing geometry with sheared wing tips

NASA Technical Reports Server (NTRS)

Fremaux, C. M.; Vijgen, P. M. H. W.; Van Dam, C. P.

1990-01-01

A computational parameter study is presented of potential reductions in induced drag and increases in lateral-directional stability due to sheared wing tips attached to an untwisted wing of moderate sweep and aspect ratio. Sheared tips are swept and tapered wing-tip devices mounted in the plane of the wing. The induced-drag results are obtained using an inviscid, incompressible surface-panel method that models the nonlinear effects due to the deflected and rolled-up wake behind the lifting surface. The induced-drag results with planar sheared tips are compared to straight-tapered tip extensions and nonplanar winglet geometries. The lateral-directional static-stability characteristics of the wing with sheared tips are estimated using a quasi-vortex-lattice method. For certain combinations of sheared-tip sweep and taper, both the induced efficiency of the wing and the relevant static-stability derivatives are predicted to increase compared to the wing with a straight-tapered tip modification.

Ka-Band Digital Beamforming and SweepSAR Demonstration for Ice and Solid Earth Topography

NASA Technical Reports Server (NTRS)

Sadowy, Gregory; Ghaemi, Hirad; Heavy, Brandon; Perkovic, Dragana; Quddus, Momin; Zawadzki, Mark; Moller, Delwyn

2010-01-01

GLISTIN is an instrument concept for a single-pass interferometric SAR operating at 35.6 GHz. To achieve large swath widths using practical levels of transmitter power, a digitally-beamformed planar waveguide array is used. This paper describes results from a ground-based demonstration of a 16-receiver prototype. Furthermore, SweepSAR is emerging as promising technique for achieving very wide swaths for surface change detection. NASA and DLR are studying this approach for the DESDynI and Tandem-L missions. SweepSAR employs a reflector with a digitally-beamformed array feed. We will describe development of an airborne demonstration of SweepSAR using the GLISTIN receiver array and a reflector.

Hybrid massively parallel fast sweeping method for static Hamilton-Jacobi equations

NASA Astrophysics Data System (ADS)

Detrixhe, Miles; Gibou, Frédéric

2016-10-01

The fast sweeping method is a popular algorithm for solving a variety of static Hamilton-Jacobi equations. Fast sweeping algorithms for parallel computing have been developed, but are severely limited. In this work, we present a multilevel, hybrid parallel algorithm that combines the desirable traits of two distinct parallel methods. The fine and coarse grained components of the algorithm take advantage of heterogeneous computer architecture common in high performance computing facilities. We present the algorithm and demonstrate its effectiveness on a set of example problems including optimal control, dynamic games, and seismic wave propagation. We give results for convergence, parallel scaling, and show state-of-the-art speedup values for the fast sweeping method.

Modeling of long range frequency sweeping for energetic particle modes

NASA Astrophysics Data System (ADS)

Nyqvist, R. M.; Breizman, B. N.

2013-04-01

Long range frequency sweeping events are simulated numerically within a one-dimensional, electrostatic bump-on-tail model with fast particle sources and collisions. The numerical solution accounts for fast particle trapping and detrapping in an evolving wave field with a fixed wavelength, and it includes three distinct collisions operators: Drag (dynamical friction on the background electrons), Krook-type collisions, and velocity space diffusion. The effects of particle trapping and diffusion on the evolution of holes and clumps are investigated, and the occurrence of non-monotonic (hooked) frequency sweeping and asymptotically steady holes is discussed. The presented solution constitutes a step towards predictive modeling of frequency sweeping events in more realistic geometries.

Langmuir probe diagnostics of an atmospheric pressure, vortex-stabilized nitrogen plasma jet

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

Prevosto, L.; Mancinelli, B. R.; Kelly, H.

Langmuir probe measurements in an atmospheric pressure direct current (dc) plasma jet are reported. Sweeping probes were used. The experiment was carried out using a dc non-transferred arc torch with a rod-type cathode and an anode of 5 mm diameter. The torch was operated at a nominal power level of 15 kW with a nitrogen flow rate of 25 Nl min{sup -1}. A flat ion saturation region was found in the current-voltage curve of the probe. The ion saturation current to a cylindrical probe in a high-pressure non local thermal equilibrium (LTE) plasma was modeled. Thermal effects and ionization/recombination processesmore » inside the probe perturbed region were taken into account. Averaged radial profiles of the electron and heavy particle temperatures as well as the electron density were obtained. An electron temperature around 11 000 K, a heavy particle temperature around 9500 K and an electron density of about 4 Multiplication-Sign 10{sup 22} m{sup -3}, were found at the jet centre at 3.5 mm downstream from the torch exit. Large deviations from kinetic equilibrium were found throughout the plasma jet. The electron and heavy particle temperature profiles showed good agreement with those reported in the literature by using spectroscopic techniques. It was also found that the temperature radial profile based on LTE was very close to that of the electrons. The calculations have shown that this method is particularly useful for studying spraying-type plasma jets characterized by electron temperatures in the range 9000-14 000 K.« less

Dendritic Cells and Programmed Death-1 Blockade: A Joint Venture to Combat Cancer.

PubMed

Versteven, Maarten; Van den Bergh, Johan M J; Marcq, Elly; Smits, Evelien L J; Van Tendeloo, Viggo F I; Hobo, Willemijn; Lion, Eva

2018-01-01

Two decades of clinical cancer research with dendritic cell (DC)-based vaccination have proved that this type of personalized medicine is safe and has the capacity to improve survival, but monotherapy is unlikely to cure the cancer. Designed to empower the patient's antitumor immunity, huge research efforts are set to improve the efficacy of next-generation DC vaccines and to find synergistic combinations with existing cancer therapies. Immune checkpoint approaches, aiming to breach immune suppression and evasion to reinforce antitumor immunity, have been a revelation in the immunotherapy field. Early success of therapeutic antibodies blocking the programmed death-1 (PD-1) pathway has sparked the development of novel inhibitors and combination therapies. Hence, merging immunoregulatory tumor-specific DC strategies with PD-1-targeted approaches is a promising path to explore. In this review, we focus on the role of PD-1-signaling in DC-mediated antitumor immunity. In the quest of exploiting the full potential of DC therapy, different strategies to leverage DC immunopotency by impeding PD-1-mediated immune regulation are discussed, including the most advanced research on targeted therapeutic antibodies, lessons learned from chemotherapy-induced immune activation, and more recent developments with soluble molecules and gene-silencing techniques. An overview of DC/PD-1 immunotherapy combinations that are currently under preclinical and clinical investigation substantiates the clinical potential of such combination strategies.

DC-SIGN activation mediates the differential effects of SAP and CRP on the innate immune system and inhibits fibrosis in mice.

PubMed

Cox, Nehemiah; Pilling, Darrell; Gomer, Richard H

2015-07-07

Fibrosis is caused by scar tissue formation in internal organs and is associated with 45% of deaths in the United States. Two closely related human serum proteins, serum amyloid P (SAP) and C-reactive protein (CRP), strongly affect fibrosis. In multiple animal models, and in Phase 1 and Phase 2 clinical trials, SAP affects several aspects of the innate immune system to reduce fibrosis, whereas CRP appears to potentiate fibrosis. However, SAP and CRP bind the same Fcγ receptors (FcγR) with similar affinities, and why SAP and CRP have opposing effects is unknown. Here, we report that SAP but not CRP binds the receptor DC-SIGN (SIGN-R1) to affect the innate immune system, and that FcγR are not necessary for SAP function. A polycyclic aminothiazole DC-SIGN ligand and anti-DC-SIGN antibodies mimic SAP effects in vitro. In mice, the aminothiazole reduces neutrophil accumulation in a model of acute lung inflammation and, at 0.001 mg/kg, alleviates pulmonary fibrosis by increasing levels of the immunosuppressant IL-10. DC-SIGN (SIGN-R1) is present on mouse lung epithelial cells, and SAP and the aminothiazole potentiate IL-10 production from these cells. Our data suggest that SAP activates DC-SIGN to regulate the innate immune system differently from CRP, and that DC-SIGN is a target for antifibrotics.

Dendritic Cells and Programmed Death-1 Blockade: A Joint Venture to Combat Cancer

PubMed Central

Versteven, Maarten; Van den Bergh, Johan M. J.; Marcq, Elly; Smits, Evelien L. J.; Van Tendeloo, Viggo F. I.; Hobo, Willemijn; Lion, Eva

2018-01-01

Two decades of clinical cancer research with dendritic cell (DC)-based vaccination have proved that this type of personalized medicine is safe and has the capacity to improve survival, but monotherapy is unlikely to cure the cancer. Designed to empower the patient’s antitumor immunity, huge research efforts are set to improve the efficacy of next-generation DC vaccines and to find synergistic combinations with existing cancer therapies. Immune checkpoint approaches, aiming to breach immune suppression and evasion to reinforce antitumor immunity, have been a revelation in the immunotherapy field. Early success of therapeutic antibodies blocking the programmed death-1 (PD-1) pathway has sparked the development of novel inhibitors and combination therapies. Hence, merging immunoregulatory tumor-specific DC strategies with PD-1-targeted approaches is a promising path to explore. In this review, we focus on the role of PD-1-signaling in DC-mediated antitumor immunity. In the quest of exploiting the full potential of DC therapy, different strategies to leverage DC immunopotency by impeding PD-1-mediated immune regulation are discussed, including the most advanced research on targeted therapeutic antibodies, lessons learned from chemotherapy-induced immune activation, and more recent developments with soluble molecules and gene-silencing techniques. An overview of DC/PD-1 immunotherapy combinations that are currently under preclinical and clinical investigation substantiates the clinical potential of such combination strategies. PMID:29599770

Field-programmable gate array-controlled sweep velocity-locked laser pulse generator

NASA Astrophysics Data System (ADS)

Chen, Zhen; Hefferman, Gerald; Wei, Tao

2017-05-01

A field-programmable gate array (FPGA)-controlled sweep velocity-locked laser pulse generator (SV-LLPG) design based on an all-digital phase-locked loop (ADPLL) is proposed. A distributed feedback laser with modulated injection current was used as a swept-frequency laser source. An open-loop predistortion modulation waveform was calibrated using a feedback iteration method to initially improve frequency sweep linearity. An ADPLL control system was then implemented using an FPGA to lock the output of a Mach-Zehnder interferometer that was directly proportional to laser sweep velocity to an on-board system clock. Using this system, linearly chirped laser pulses with a sweep bandwidth of 111.16 GHz were demonstrated. Further testing evaluating the sensing utility of the system was conducted. In this test, the SV-LLPG served as the swept laser source of an optical frequency-domain reflectometry system used to interrogate a subterahertz range fiber structure (sub-THz-FS) array. A static strain test was then conducted and linear sensor results were observed.

Fast backprojection-based reconstruction of spectral-spatial EPR images from projections with the constant sweep of a magnetic field.

PubMed

Komarov, Denis A; Hirata, Hiroshi

2017-08-01

In this paper, we introduce a procedure for the reconstruction of spectral-spatial EPR images using projections acquired with the constant sweep of a magnetic field. The application of a constant field-sweep and a predetermined data sampling rate simplifies the requirements for EPR imaging instrumentation and facilitates the backprojection-based reconstruction of spectral-spatial images. The proposed approach was applied to the reconstruction of a four-dimensional numerical phantom and to actual spectral-spatial EPR measurements. Image reconstruction using projections with a constant field-sweep was three times faster than the conventional approach with the application of a pseudo-angle and a scan range that depends on the applied field gradient. Spectral-spatial EPR imaging with a constant field-sweep for data acquisition only slightly reduces the signal-to-noise ratio or functional resolution of the resultant images and can be applied together with any common backprojection-based reconstruction algorithm. Copyright © 2017 Elsevier Inc. All rights reserved.

Fine-Mapping and Selective Sweep Analysis of QTL for Cold Tolerance in Drosophila melanogaster

PubMed Central

Wilches, Ricardo; Voigt, Susanne; Duchen, Pablo; Laurent, Stefan; Stephan, Wolfgang

2014-01-01

There is a growing interest in investigating the relationship between genes with signatures of natural selection and genes identified in QTL mapping studies using combined population and quantitative genetics approaches. We dissected an X-linked interval of 6.2 Mb, which contains two QTL underlying variation in chill coma recovery time (CCRT) in Drosophila melanogaster from temperate (European) and tropical (African) regions. This resulted in two relatively small regions of 131 kb and 124 kb. The latter one co-localizes with a very strong selective sweep in the European population. We examined the genes within and near the sweep region individually using gene expression analysis and P-element insertion lines. Of the genes overlapping with the sweep, none appears to be related to CCRT. However, we have identified a new candidate gene of CCRT, brinker, which is located just outside the sweep region and is inducible by cold stress. We discuss these results in light of recent population genetics theories on quantitative traits. PMID:24970882

NADH fluorescence imaging and the histological impact of cortical spreading depolarization during the acute phase of subarachnoid hemorrhage in rats.

PubMed

Shimizu, Tomohisa; Hishikawa, Tomohito; Nishihiro, Shingo; Shinji, Yukei; Takasugi, Yuji; Haruma, Jun; Hiramatsu, Masafumi; Kawase, Hirokazu; Sato, Sachiko; Mizoue, Ryoichi; Takeda, Yoshimasa; Sugiu, Kenji; Morimatsu, Hiroshi; Date, Isao

2018-01-01

OBJECTIVE Although cortical spreading depolarization (CSD) has been observed during the early phase of subarachnoid hemorrhage (SAH) in clinical settings, the pathogenicity of CSD is unclear. The aim of this study is to elucidate the effects of loss of membrane potential on neuronal damage during the acute phase of SAH. METHODS Twenty-four rats were subjected to SAH by the perforation method. The propagation of depolarization in the brain cortex was examined by using electrodes to monitor 2 direct-current (DC) potentials and obtaining NADH (reduced nicotinamide adenine dinucleotide) fluorescence images while exposing the parietal-temporal cortex to ultraviolet light. Cerebral blood flow (CBF) was monitored in the vicinity of the lateral electrode. Twenty-four hours after onset of SAH, histological damage was evaluated at the DC potential recording sites. RESULTS Changes in DC potentials (n = 48 in total) were sorted into 3 types according to the appearance of ischemic depolarization in the entire hemisphere following induction of SAH. In Type 1 changes (n = 21), ischemic depolarization was not observed during a 1-hour observation period. In Type 2 changes (n = 13), the DC potential demonstrated ischemic depolarization on initiation of SAH and recovered 80% from the maximal DC deflection during a 1-hour observation period (33.3 ± 15.8 minutes). In Type 3 changes (n = 14), the DC potential displayed ischemic depolarization and did not recover during a 1-hour observation period. Histological evaluations at DC potential recording sites showed intact tissue at all sites in the Type 1 group, whereas in the Type 2 and Type 3 groups neuronal damage of varying severity was observed depending on the duration of ischemic depolarization. The duration of depolarization that causes injury to 50% of neurons (P 50 ) was estimated to be 22.4 minutes (95% confidence intervals 17.0-30.3 minutes). CSD was observed in 3 rats at 6 sites in the Type 1 group 5.1 ± 2.2 minutes after initiation of SAH. On NADH fluorescence images CSD was initially observed in the anterior cortex; it propagated through the entire hemisphere in the direction of the occipital cortex at a rate of 3 mm/minute, with repolarization in 2.3 ± 1.2 minutes. DC potential recording sites that had undergone CSD were found to have intact tissue 24 hours later. Compared with depolarization that caused 50% neuronal damage, the duration of CSD was too short to cause histological damage. CONCLUSIONS CSD was successfully visualized using NADH fluorescence. It propagated from the anterior to the posterior cortex along with an increase in CBF. The duration of depolarization in CSD (2.3 ± 1.2 minutes) was far shorter than that causing 50% neuronal damage (22.4 minutes) and was not associated with histological damage in the current experimental setting.

DFT-based molecular modeling and vibrational study of the La(III) complex of 3,3'-(benzylidene)bis(4-hydroxycoumarin).

PubMed

Mihaylov, Tzvetan; Trendafilova, Natasha; Georgieva, Ivelina

2008-05-01

Molecular modeling of the La(III) complex of 3,3'-(benzylidene)bis(4-hydroxycoumarin) (PhDC) was performed using density functional theory (DFT) methods at B3LYP/6-31G(d) and BP86/TZP levels. Both Stuttgart-Dresden effective core potential and ZORA approximation were applied to the La(III) center. The electron density distribution and the nucleophilic centers of the deprotonated ligand PhDC(2-) in a solvent environment were estimated on the basis of Hirshfeld atomic charges, electrostatic potential values at the nuclei, and Nalewajski-Mrozek bond orders. In accordance with the empirical formula La(PhDC)(OH)(H(2)O), a chain structure of the complex was simulated by means of two types of molecular fragment: (1) two La(III) cations bound to one PhDC(2-) ligand, and (2) two PhDC(2-) ligands bound to one La(III) cation. Different orientations of PhDC(2-), OH(-) and H(2)O ligands in the La(III) complexes were investigated using 20 possible [La(PhDC(2-))(2)(OH)(H(2)O)](2-) fragments. Energy calculations predicted that the prism-like structure based on "tail-head" cis-LML2 type binding and stabilized via HO...HOH intramolecular hydrogen bonds is the most probable structure for the La(III) complex. The calculated vibrational spectrum of the lowest energy La(III) model fragment is in very good agreement with the experimental IR spectrum of the complex, supporting the suggested ligand binding mode to La(III) in a chain structure, namely, every PhDC(2-) interacts with two La(III) cations through both carbonylic and both hydroxylic oxygens, and every La(III) cation binds four oxygen atoms of two different PhDC(2-).

Validation of SWEEP for creep, saltation, and suspension in a desert-oasis ecotone

NASA Astrophysics Data System (ADS)

Pi, H.; Sharratt, B.; Feng, G.; Lei, J.; Li, X.; Zheng, Z.

2016-03-01

Wind erosion in the desert-oasis ecotone can accelerate desertification, but little is known about the susceptibility of the ecotone to wind erosion in the Tarim Basin despite being a major source of windblown dust in China. The objective of this study was to test the performance of the Single-event Wind Erosion Evaluation Program (SWEEP) in simulating soil loss as creep, saltation, and suspension in a desert-oasis ecotone. Creep, saltation, and suspension were measured and simulated in a desert-oasis ecotone of the Tarim Basin during discrete periods of high winds in spring 2012 and 2013. The model appeared to adequately simulate total soil loss (ranged from 23 to 2272 g m-2 across sample periods) according to the high index of agreement (d = 0.76). The adequate agreement of the SWEEP in simulating total soil loss was due to the good performance of the model (d = 0.71) in simulating creep plus saltation. The SWEEP model, however, inadequately simulated suspension based upon a low d (⩽0.43). The slope estimates of the regression between simulated and measured suspension and difference of mean suggested that the SWEEP underestimated suspension. The adequate simulation of creep plus saltation thus provides reasonable estimates of total soil loss using SWEEP in a desert-oasis environment.

Method and system for producing sputtered thin films with sub-angstrom thickness uniformity or custom thickness gradients

DOEpatents

Folta, James A.; Montcalm, Claude; Walton, Christopher

2003-01-01

A method and system for producing a thin film with highly uniform (or highly accurate custom graded) thickness on a flat or graded substrate (such as concave or convex optics), by sweeping the substrate across a vapor deposition source with controlled (and generally, time-varying) velocity. In preferred embodiments, the method includes the steps of measuring the source flux distribution (using a test piece that is held stationary while exposed to the source), calculating a set of predicted film thickness profiles, each film thickness profile assuming the measured flux distribution and a different one of a set of sweep velocity modulation recipes, and determining from the predicted film thickness profiles a sweep velocity modulation recipe which is adequate to achieve a predetermined thickness profile. Aspects of the invention include a practical method of accurately measuring source flux distribution, and a computer-implemented method employing a graphical user interface to facilitate convenient selection of an optimal or nearly optimal sweep velocity modulation recipe to achieve a desired thickness profile on a substrate. Preferably, the computer implements an algorithm in which many sweep velocity function parameters (for example, the speed at which each substrate spins about its center as it sweeps across the source) can be varied or set to zero.

Reduction of non-point source contaminants associated with road-deposited sediments by sweeping.

PubMed

Kim, Do-Gun; Kang, Hee-Man; Ko, Seok-Oh

2017-09-19

Road-deposited sediments (RDS) on an expressway, residual RDS collected after sweeping, and RDS removed by means of sweeping were analyzed to evaluate the degree to which sweeping removed various non-point source contaminants. The total RDS load was 393.1 ± 80.3 kg/km and the RDS, residual RDS, and swept RDS were all highly polluted with organics, nutrients, and metals. Among the metals studied, Cu, Zn, Pb, Ni, Ca, and Fe were significantly enriched, and most of the contaminants were associated with particles within the size range from 63 μm to 2 mm. Sweeping reduced RDS and its associated contaminants by 33.3-49.1% on average. We also measured the biological oxygen demand (BOD) of RDS in the present work, representing to our knowledge the first time that this has been done; we found that RDS contains a significant amount of biodegradable organics and that the reduction of BOD by sweeping was higher than that of other contaminants. Significant correlations were found between the contaminants measured, indicating that the organics and the metals originated from both exhaust and non-exhaust particles. Meanwhile, the concentrations of Cu and Ni were higher in 63 μm-2 mm particles than in smaller particles, suggesting that some metals in RDS likely exist intrinsically in particles, rather than only as adsorbates on particle surfaces. Overall, the results in this study showed that sweeping to collect RDS can be a good alternative for reduction of contaminants in runoff.

Direct current electrical potential measurement of the growth of small cracks

NASA Technical Reports Server (NTRS)

Gangloff, Richard P.; Slavik, Donald C.; Piascik, Robert S.; Van Stone, Robert H.

1992-01-01

The analytical and experimental aspects of the direct-current electrical potential difference (dcEPD) method for continuous monitoring of the growth kinetics of short (50 to 500 microns) fatigue cracks are reviewed, and successful applications of the deEPD method to study fatigue crack propagation in a variety of metallic alloys exposed to various environments are described. Particular attention is given to the principle of the dcEPD method, the analytical electrical potential calibration relationships, and the experimental procedures and equipment.

ALA-PDT mediated DC vaccine for skin squamous cell carcinoma

NASA Astrophysics Data System (ADS)

Ji, Jie; Fan, Zhixia; Zhou, Feifan; Wang, Xiaojie; Shi, Lei; Zhang, Haiyan; Wang, Peiru; Yang, Degang; Zhang, Linglin; Wang, Xiuli; Chen, Wei R.

2015-03-01

Dendritic cell (DC) based vaccine has emerged as a promising immunotherapy for cancers. However, most DC vaccines so far have only achieved limited success in cancer treatment. Photodynamic therapy (PDT), an established cancer treatment strategy, can cause immunogenic apoptosis to induce an effective antitumor immune response. In this study, we developed a DC-based cancer vaccine using immunogenic apoptotic tumor cells induced by 5-aminolevulinic acid (ALA) mediated PDT. The maturation of DCs induced by PDT-treated apoptotic cells was evaluated. The anti-tumor immunity of ALA-PDT-DC vaccine was tested with mouse model. We observed the maturations of DCs potentiated by ALA-PDT treated tumor cells, including phenotypic maturation (upregulation of surface expression of MHC-II, DC80, and CD86), and functional maturation (enhanced capability to secret INF-Υ and IL-12). ALA-PDT-DC vaccine mediated by apoptotic cells provided protection against tumor in mice, far stronger than that of DC vaccine obtained from freeze/thaw treated tumor cells. Our results indicate that immunogenic apoptotic tumor cells can be more effective in enhancing DC-based cancer vaccine, which could improve the clinical application of PDT- DC vaccines.

Protein arginine (N)-methyl transferase 7 (PRMT7) as a potential target for the sensitization of tumor cells to camptothecins.

PubMed

Verbiest, Vincent; Montaudon, Danièle; Tautu, Michel T; Moukarzel, Joyce; Portail, Jean-Pierre; Markovits, Judith; Robert, Jacques; Ichas, François; Pourquier, Philippe

2008-04-30

PRMT7 belongs to the protein arginine methyl-transferases family. We show that downregulation of PRMT7alpha and beta isoforms in DC-3F hamster cells was associated with increased sensitivity to the Top1 inhibitor camptothecin (CPT). This effect was not due to a change in Top1 contents or catalytic activity, or to a difference in the reversal of DNA breaks. Overexpression of PRMT7alpha and beta in DC-3F cells had no effect on CPT sensitivity, whereas it conferred a resistance to DC-3F/9-OH-E cells for which both isoforms are reduced by two- to three-fold as compared to DC-3F parental cells. Finally, downregulation of the human PRMT7 could also sensitize HeLa cells to CPT, suggesting that it could be used as a target to potentiate CPT derivatives.

Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products

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

Moran, James J.; Fraga, Carlos G.; Nims, Megan K.

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. It is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ13C analysis to be used as a fingerprinting toolmore » in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a measureable isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.« less

Expression of human immunodeficiency virus (HIV)-binding lectin DC-SIGNR: Consequences for HIV infection and immunity.

PubMed

Soilleux, Elizabeth J; Morris, Lesley S; Rushbrook, Simon; Lee, Benhur; Coleman, Nicholas

2002-06-01

DC-SIGNR is a human immunodeficiency virus (HIV)-binding C-type lectin that is expressed on endothelium in the hepatic sinusoids, lymph node sinuses and placenta. Like closely related DC-SIGN, DC-SIGNR can bind both ICAM-3 and HIV and can potentiate HIV infection of T lymphocytes in trans. In the present study we have investigated reasons underlying the restricted distribution of DC-SIGNR and have examined DC-SIGNR expression in relation to HIV entry receptors. We show that DC-SIGNR expression does not depend on endothelial cell specialization or on activation state. DC-SIGNR-positive endothelium continues to express DC-SIGNR in conditions of hyperplasia, whereas the molecule is lost after neoplastic transformation, most likely as a result of changes in the microenvironment of the endothelial cells. We have further shown that CCR5, but not CD4, is coexpressed with DC-SIGNR on hepatic sinusoidal and placental capillary endothelial cells. However, CD4-positive CCR5-positive cells, such as hepatic Kupffer cells, placental Hofbauer cells, and CD4-positive T lymphocytes in lymph nodes, can be found adjacent to DC-SIGNR-positive endothelium. Therefore, DC-SIGNR may be able to mediate HIV infection of these cells in trans. Finally, we demonstrate that DC-SIGN and DC-SIGNR can be coexpressed on lymph node sinus endothelial cells, which may lead to modulation of the function of both molecules. Copyright 2002, Elsevier Science (USA). All rights reserved.

Effect of curve sawing on lumber recovery and warp of short cherry logs containing sweep

Treesearch

Brian H. Bond; Philip Araman

2008-01-01

It has been estimated that approximately one-third of hardwood sawlogs have a significant amount of sweep and that 7 to nearly 40 percent of the yield is lost from logs that have greater than 1 inch of sweep. While decreased yield is important, for hardwood logs the loss of lumber value is likely more significant. A method that produced lumber while accounting for log...

Southwest Energy Efficiency Project (SWEEP) Final Report

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

Geller, Howard; Meyers, Jim

SWEEP worked with Energy Efficiency and Renewable Energy (EERE) programs to foster greater energy efficiency throughout the Southwest. SWEEP accomplished this through a combination of analysis and support; preparation and distribution of materials on best practice technologies, policies and programs; and technical assistance and information dissemination to states and municipalities in the southwest supporting BTO, AMO, OWIP for advancement of efficiency in products and practices. These efforts were accomplished during the period 2012 through 2017.

Cadmium Electrode Investigation.

DTIC Science & Technology

1980-03-01

pensation in the sweep voltammetry experiments. For the galvanostatic pulse experiments, the IR-bridge compensation network was employed. Plate...characteristics of the porous minielectrodes in 2M Cd(N03 )2 are strongly temperature dependent. Linear sweep voltamograms were done at 250C and 750C. Those done...at 250C were of the same shape as obtained by Maloy (Ref 1) provided that the sweep rate was no higher than 2mv/sec. Similarly obtained voltamograms

Hybrid massively parallel fast sweeping method for static Hamilton–Jacobi equations

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

Detrixhe, Miles, E-mail: mdetrixhe@engineering.ucsb.edu; University of California Santa Barbara, Santa Barbara, CA, 93106; Gibou, Frédéric, E-mail: fgibou@engineering.ucsb.edu

The fast sweeping method is a popular algorithm for solving a variety of static Hamilton–Jacobi equations. Fast sweeping algorithms for parallel computing have been developed, but are severely limited. In this work, we present a multilevel, hybrid parallel algorithm that combines the desirable traits of two distinct parallel methods. The fine and coarse grained components of the algorithm take advantage of heterogeneous computer architecture common in high performance computing facilities. We present the algorithm and demonstrate its effectiveness on a set of example problems including optimal control, dynamic games, and seismic wave propagation. We give results for convergence, parallel scaling,more » and show state-of-the-art speedup values for the fast sweeping method.« less

Cleaning mechanism of particle contaminants on large aperture optical components by using air knife sweeping technology

NASA Astrophysics Data System (ADS)

Niu, Longfei; Liu, Hao; Miao, Xinxiang; Lv, Haibing; Yuan, Xiaodong; Zhou, Hai; Yao, Caizhen; Zhou, Guorui; Li, Qin

2017-05-01

The cleaning mechanism of optical surface particle contaminants in the light pneumatic tube was simulated based on the static equations and JKR model. Cleaning verification experiment based on air knife sweeping system and on-line monitoring system in high power laser facility was set up in order to verify the simulated results. Results showed that the removal ratio is significantly influenced by sweeping velocity and angle. The removal ratio can reach to 94.3% by using higher input pressure of the air knife, demonstrating that the air knife sweeping technology is useful for maintaining the surface cleanliness of optical elements, and thus guaranteeing the long-term stable running of the high power laser facility.

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.

Development and Use of a Cyclic Voltammetry Simulator to Introduce Undergraduate Students to Electrochemical Simulations

ERIC Educational Resources Information Center

Brown, Jay H.

2015-01-01

Cyclic voltammetry (CV) is a popular technique for the study of electrochemical mechanisms because the method can provide useful information on the redox couple. The technique involves the application of a potential ramp on an unstirred solution while the current is monitored, and then the ramp is reversed for a return sweep. CV is sometimes…

Leaching behaviour of different scrap materials at recovery and recycling companies: full-, pilot- and lab-scale investigation.

PubMed

Blondeel, E; Chys, M; Depuydt, V; Folens, K; Du Laing, G; Verliefde, A; Van Hulle, S W H

2014-12-01

Scrap material recovery and recycling companies are confronted with waste water that has a highly fluctuating flow rate and composition. Common pollutants, such as COD, nutrients and suspended solids, potentially toxic metals, polyaromatic hydrocarbons and poly chlorinated biphenyls can exceed the discharge limits. An analysis of the leaching behaviour of different scrap materials and scrap yard sweepings was performed at full-scale, pilot-scale and lab-scale in order to find possible preventive solutions for this waste water problem. The results of these leaching tests (with concentrations that frequently exceeded the Flemish discharge limits) showed the importance of regular sweeping campaigns at the company, leak proof or covered storage of specific scrap materials and oil/water separation on particular leachates. The particulate versus dissolved fraction was also studied for the pollutants. For example, up to 98% of the polyaromatic hydrocarbons, poly chlorinated biphenyls and some metals were in the particulate form. This confirms the (potential) applicability of sedimentation and filtration techniques for the treatment of the majority of the leachates, and as such the rainwater run-off as a whole. Copyright © 2014 Elsevier Ltd. All rights reserved.

Simultaneous measurement of skin potential and conductance in electrodermal response monitoring

NASA Astrophysics Data System (ADS)

Jabbari, A.; Johnsen, B.; Grimnes, S.; Martinsen, Ø. G.

2010-04-01

Measurement of electrodermal activity (EDA) has been an important tool in psychophysiological research. The emotional sweat activity is very sensitive to psychological stimuli or conditions. The changes are easily detected by means of electrical measurements and since the sweat ducts are predominantly resistive, a low-frequency conductance measurement is appropriate for measurement of skin conductance in electrodermal response. The main purpose of this study was to develop a measuring system where DC current was replaced by a small AC current in a system so the DC potential and AC conductance could be measured simultaneously at the same skin site. A small, battery operated, PDA based instrument has been developed. The preliminary results of this ongoing study show that there is additional information in the DC potential channel and that different stimuli seem to produce slightly different response patterns.

Induction of dendritic cell migration upon Toxoplasma gondii infection potentiates parasite dissemination.

PubMed

Lambert, Henrik; Hitziger, Niclas; Dellacasa, Isabel; Svensson, Mattias; Barragan, Antonio

2006-10-01

The processes leading to systemic dissemination of the obligate intracellular parasite Toxoplasma gondii remain unelucidated. In vitro studies on human and murine dendritic cells (DC) revealed that active invasion of DC by Toxoplasma induces a state of hypermotility in DC, enabling transmigration of infected DC across endothelial cell monolayers in the absence of chemotactic stimuli. Infected DC exhibited upregulation of maturation markers and co-stimulatory molecules. While modulation of cell adhesion molecules CD11/CD18 was similar for Toxoplasma-infected DC and lipopolysaccharide (LPS)-matured DC, Toxoplasma-infected DC did not exhibit upregulation of CD54/ICAM-1. Induction of host cell migration in vitro required live intracellular parasite(s) and was inhibited by uncoupling the Gi-protein signalling pathway with pertussis toxin, but did not depend on CCR5, CCR7 or Toll/interleukin-1 receptor signalling. When migration of Toxoplasma-infected DC was compared with migration of LPS-stimulated DC in vivo, similar or higher numbers of Toxoplasma-infected DC reached the mesenteric lymph nodes and spleen respectively. Adoptive transfer of Toxoplasma-infected DC resulted in more rapid dissemination of parasites to distant organs and in exacerbation of infection compared with inoculation with free parasites. Altogether, these findings show that Toxoplasma is able to subvert the regulation of host cell motility and likely exploits the host's natural pathways of cellular migration for parasite dissemination.

Electrochemical reduction of carbon fluorine bond in 4-fluorobenzonitrile Mechanistic analysis employing Marcus Hush quadratic activation-driving force relation

NASA Astrophysics Data System (ADS)

Muthukrishnan, A.; Sangaranarayanan, M. V.

2007-10-01

The reduction of carbon-fluorine bond in 4-fluorobenzonitrile in acetonitrile as the solvent, is analyzed using convolution potential sweep voltammetry and the dependence of the transfer coefficient on potential is investigated within the framework of Marcus-Hush quadratic activation-driving force theory. The validity of stepwise mechanism is inferred from solvent reorganization energy estimates as well as bond length calculations using B3LYP/6-31g(d) method. A novel method of estimating the standard reduction potential of the 4-fluorobenzonitrile in acetonitrile is proposed.

Underpotential deposition-mediated layer-by-layer growth of thin films

DOEpatents

Wang, Jia Xu; Adzic, Radoslav R.

2017-06-27

A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves electrochemically exchanging a mediating element on a substrate with a noble metal film by alternatingly sweeping potential in forward and reverse directions for a predetermined number of times in an electrochemical cell. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis.

An integrated CMOS bio-potential amplifier with a feed-forward DC cancellation topology.

PubMed

Parthasarathy, Jayant; Erdman, Arthur G; Redish, Aaron D; Ziaie, Babak

2006-01-01

This paper describes a novel technique to realize an integrated CMOS bio-potential amplifier with a feedforward DC cancellation topology. The amplifier is designed to provide substantial DC cancellation even while amplifying very low frequency signals. More than 80 dB offset rejection ratio is achieved without any external capacitors. The cancellation scheme is robust against process and temperature variations. The amplifier is fabricated through MOSIS AMI 1.5 microm technology (0.05 mm2 area). Measurement results show a gain of 43.5 dB in the pass band (<1 mHz-5 KHz), an input referred noise of 3.66 microVrms, and a current consumption of 22 microA.

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

Liu, Wei; Zhang, Xingyi, E-mail: zhangxingyi@lzu.edu.cn; Liu, Cong

We construct a visible instrument to study the mechanical-electro behaviors of high temperature superconducting tape as a function of magnetic field, strain, and temperature. This apparatus is directly cooled by a commercial Gifford-McMahon cryocooler. The minimum temperature of sample can be 8.75 K. A proportion integration differentiation temperature control is used, which is capable of producing continuous variation of specimen temperature from 8.75 K to 300 K with an optional temperature sweep rate. We use an external loading device to stretch the superconducting tape quasi-statically with the maximum tension strain of 20%. A superconducting magnet manufactured by the NbTi strandmore » is applied to provide magnetic field up to 5 T with a homogeneous range of 110 mm. The maximum fluctuation of the magnetic field is less than 1%. We design a kind of superconducting lead composed of YBa2Cu3O7-x coated conductor and beryllium copper alloy (BeCu) to transfer DC to the superconducting sample with the maximum value of 600 A. Most notably, this apparatus allows in situ observation of the electromagnetic property of superconducting tape using the classical magnetic-optical imaging.« less

Impact of ultra-thin Al2O3-y layers on TiO2-x ReRAM switching characteristics

NASA Astrophysics Data System (ADS)

Trapatseli, Maria; Cortese, Simone; Serb, Alexander; Khiat, Ali; Prodromakis, Themistoklis

2017-05-01

Transition metal-oxide resistive random access memory devices have demonstrated excellent performance in switching speed, versatility of switching and low-power operation. However, this technology still faces challenges like poor cycling endurance, degradation due to high electroforming (EF) switching voltages and low yields. Approaches such as engineering of the active layer by doping or addition of thin oxide buffer layers have been often adopted to tackle these problems. Here, we have followed a strategy that combines the two; we have used ultra-thin Al2O3-y buffer layers incorporated between TiO2-x thin films taking into account both 3+/4+ oxidation states of Al/Ti cations. Our devices were tested by DC and pulsed voltage sweeping and in both cases demonstrated improved switching voltages. We believe that the Al2O3-y layers act as reservoirs of oxygen vacancies which are injected during EF, facilitate a filamentary switching mechanism and provide enhanced filament stability, as shown by the cycling endurance measurements.

Exact solutions for oscillatory shear sweep behaviors of complex fluids from the Oldroyd 8-constant framework

NASA Astrophysics Data System (ADS)

Saengow, Chaimongkol; Giacomin, A. Jeffrey

2018-03-01

In this paper, we provide a new exact framework for analyzing the most commonly measured behaviors in large-amplitude oscillatory shear flow (LAOS), a popular flow for studying the nonlinear physics of complex fluids. Specifically, the strain rate sweep (also called the strain sweep) is used routinely to identify the onset of nonlinearity. By the strain rate sweep, we mean a sequence of LAOS experiments conducted at the same frequency, performed one after another, with increasing shear rate amplitude. In this paper, we give exact expressions for the nonlinear complex viscosity and the corresponding nonlinear complex normal stress coefficients, for the Oldroyd 8-constant framework for oscillatory shear sweeps. We choose the Oldroyd 8-constant framework for its rich diversity of popular special cases (we list 18 of these). We evaluate the Fourier integrals of our previous exact solution to get exact expressions for the real and imaginary parts of the complex viscosity, and for the complex normal stress coefficients, as functions of both test frequency and shear rate amplitude. We explore the role of infinite shear rate viscosity on strain rate sweep responses for the special case of the corotational Jeffreys fluid. We find that raising η∞ raises the real part of the complex viscosity and lowers the imaginary. In our worked examples, we thus first use the corotational Jeffreys fluid, and then, for greater accuracy, we use the Johnson-Segalman fluid, to describe the strain rate sweep response of molten atactic polystyrene. For our comparisons with data, we use the Spriggs relations to generalize the Oldroyd 8-constant framework to multimode. Our generalization yields unequivocally, a longest fluid relaxation time, used to assign Weissenberg and Deborah numbers to each oscillatory shear flow experiment. We then locate each experiment in the Pipkin space.

Signatures of soft sweeps across the Dt1 locus underlying determinate growth habit in soya bean [Glycine max (L.) Merr.].

PubMed

Zhong, Limei; Yang, Qiaomei; Yan, Xin; Yu, Chao; Su, Liu; Zhang, Xifeng; Zhu, Youlin

2017-09-01

Determinate growth habit is an agronomically important trait associated with domestication in soya bean. Previous studies have demonstrated that the emergence of determinacy is correlated with artificial selection on four nonsynonymous mutations in the Dt1 gene. To better understand the signatures of the soft sweeps across the Dt1 locus and track the origins of the determinate alleles, we examined patterns of nucleotide variation in Dt1 and the surrounding genomic region of approximately 800 kb. Four local, asymmetrical hard sweeps on four determinate alleles, sized approximately 660, 120, 220 and 150 kb, were identified, which constitute the soft sweeps for the adaptation. These variable-sized sweeps substantially reflected the strength and timing of selection and indicated that the selection on the alleles had been completed rapidly within half a century. Statistics of EHH, iHS, H12 and H2/H1 based on haplotype data had the power to detect the soft sweeps, revealing distinct signatures of extensive long-range LD and haplotype homozygosity, and multiple frequent adaptive haplotypes. A haplotype network constructed for Dt1 and a phylogenetic tree based on its extended haplotype block implied independent sources of the adaptive alleles through de novo mutations or rare standing variation in quick succession during the selective phase, strongly supporting multiple origins of the determinacy. We propose that the adaptation of soya bean determinacy is guided by a model of soft sweeps and that this model might be indispensable during crop domestication or evolution. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

R2d2 Drives Selfish Sweeps in the House Mouse.

PubMed

Didion, John P; Morgan, Andrew P; Yadgary, Liran; Bell, Timothy A; McMullan, Rachel C; Ortiz de Solorzano, Lydia; Britton-Davidian, Janice; Bult, Carol J; Campbell, Karl J; Castiglia, Riccardo; Ching, Yung-Hao; Chunco, Amanda J; Crowley, James J; Chesler, Elissa J; Förster, Daniel W; French, John E; Gabriel, Sofia I; Gatti, Daniel M; Garland, Theodore; Giagia-Athanasopoulou, Eva B; Giménez, Mabel D; Grize, Sofia A; Gündüz, İslam; Holmes, Andrew; Hauffe, Heidi C; Herman, Jeremy S; Holt, James M; Hua, Kunjie; Jolley, Wesley J; Lindholm, Anna K; López-Fuster, María J; Mitsainas, George; da Luz Mathias, Maria; McMillan, Leonard; Ramalhinho, Maria da Graça Morgado; Rehermann, Barbara; Rosshart, Stephan P; Searle, Jeremy B; Shiao, Meng-Shin; Solano, Emanuela; Svenson, Karen L; Thomas-Laemont, Patricia; Threadgill, David W; Ventura, Jacint; Weinstock, George M; Pomp, Daniel; Churchill, Gary A; Pardo-Manuel de Villena, Fernando

2016-06-01

A selective sweep is the result of strong positive selection driving newly occurring or standing genetic variants to fixation, and can dramatically alter the pattern and distribution of allelic diversity in a population. Population-level sequencing data have enabled discoveries of selective sweeps associated with genes involved in recent adaptations in many species. In contrast, much debate but little evidence addresses whether "selfish" genes are capable of fixation-thereby leaving signatures identical to classical selective sweeps-despite being neutral or deleterious to organismal fitness. We previously described R2d2, a large copy-number variant that causes nonrandom segregation of mouse Chromosome 2 in females due to meiotic drive. Here we show population-genetic data consistent with a selfish sweep driven by alleles of R2d2 with high copy number (R2d2(HC)) in natural populations. We replicate this finding in multiple closed breeding populations from six outbred backgrounds segregating for R2d2 alleles. We find that R2d2(HC) rapidly increases in frequency, and in most cases becomes fixed in significantly fewer generations than can be explained by genetic drift. R2d2(HC) is also associated with significantly reduced litter sizes in heterozygous mothers, making it a true selfish allele. Our data provide direct evidence of populations actively undergoing selfish sweeps, and demonstrate that meiotic drive can rapidly alter the genomic landscape in favor of mutations with neutral or even negative effects on overall Darwinian fitness. Further study will reveal the incidence of selfish sweeps, and will elucidate the relative contributions of selfish genes, adaptation and genetic drift to evolution. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Active Flow Control Using Sweeping Jet Actuators on a Semi-Span Wing Model

NASA Technical Reports Server (NTRS)

Melton, LaTunia Pack; Koklu, Mehti

2016-01-01

Wind tunnel experiments were performed using active flow control on an unswept semispan wing model with a 30% chord trailing edge flap to aid in the selection of actuators for a planned high Reynolds number experiment. Two sweeping jet actuator sizes were investigated to determine the influence of actuator size on the active flow control system efficiency. Sweeping jet actuators with orifice sizes of 1 mm x 2 mm and 2 mm x 4 mm were selected because of the differences in actuator jet sweep angle. The parameters that were varied include actuator momentum, freestream velocity, and trailing edge flap deflection angle. Steady and unsteady pressure data, Particle Image Velocimetry data, and force and moment data were acquired to assess the performance of the two actuators. In addition to the wind tunnel experiments, benchtop studies of the actuators were performed to characterize the jets produced by each actuator. Benchtop investigations of the smaller actuator reveal that the jet exiting the actuator has a reduced sweep angle compared to published data for larger versions of this type of actuator. The larger actuator produces an oscillating jet that attaches to the external di?user walls at low supply pressures and produces the expected sweep angles. The AFC results using the smaller actuators show that while the actuators can control flow separation, the selected spacing of 3.3 cm may be too large due to the reduced sweep angle. In comparison, the spacing for the larger actuators, 6.6 cm, appears to be optimal for the Mach numbers investigated. Particle Image Velocimetry results are presented and show how the wall jets produced by the actuators cause the flow to attach to the flap surface.

W-Band Frequency-Swept EPR

PubMed Central

Hyde, James S.; Strangeway, Robert A.; Camenisch, Theodore G.; Ratke, Joseph J.; Froncisz, Wojciech

2010-01-01

This paper describes a novel experiment on nitroxide radical spin labels using a multiarm EPR W-band bridge with a loop-gap resonator (LGR). We demonstrate EPR spectroscopy of spin labels by linear sweep of the microwave frequency across the spectrum. The high bandwidth of the LGR, about 1 GHz between 3 dB points of the microwave resonance, makes this new experiment possible. A frequency-tunable yttrium iron garnet (YIG) oscillator provides sweep rates as high as 1.8 × 105 GHz/s, which corresponds to 6.3 kT/s in magnetic field-sweep units over a 44 MHz range. Two experimental domains were identified. In the first, linear frequency sweep rates were relatively slow, and pure absorption and pure dispersion spectra were obtained. This appears to be a practical mode of operation at the present level of technological development. The main advantage is the elimination of sinusoidal magnetic field modulation. In the second mode, the frequency is swept rapidly across a portion of the spectrum, and then the frequency sweep is stopped for a readout period; FID signals from a swept line oscillate at a frequency that is the difference between the spectral position of the line in frequency units and the readout position. If there is more than one line, oscillations are superimposed. The sweep rates using the YIG oscillator were too slow, and the portion of the spectrum too narrow to achieve the full EPR equivalent of Fourier transform (FT) NMR. The paper discusses technical advances required to reach this goal. The hypothesis that trapezoidal frequency sweep is an enabling technology for FT EPR is supported by this study. PMID:20462775

High glucose disrupts oligosaccharide recognition function via competitive inhibition: a potential mechanism for immune dysregulation in diabetes mellitus.

PubMed

Ilyas, Rebecca; Wallis, Russell; Soilleux, Elizabeth J; Townsend, Paul; Zehnder, Daniel; Tan, Bee K; Sim, Robert B; Lehnert, Hendrik; Randeva, Harpal S; Mitchell, Daniel A

2011-01-01

Diabetic complications include infection and cardiovascular disease. Within the immune system, host-pathogen and regulatory host-host interactions operate through binding of oligosaccharides by C-type lectin. A number of C-type lectins recognise oligosaccharides rich in mannose and fucose - sugars with similar structures to glucose. This raises the possibility that high glucose conditions in diabetes affect protein-oligosaccharide interactions via competitive inhibition. Mannose-binding lectin, soluble DC-SIGN and DC-SIGNR, and surfactant protein D, were tested for carbohydrate binding in the presence of glucose concentrations typical of diabetes, via surface plasmon resonance and affinity chromatography. Complement activation assays were performed in high glucose. DC-SIGN and DC-SIGNR expression in adipose tissues was examined via immunohistochemistry. High glucose inhibited C-type lectin binding to high-mannose glycoprotein and binding of DC-SIGN to fucosylated ligand (blood group B) was abrogated in high glucose. Complement activation via the lectin pathway was inhibited in high glucose and also in high trehalose - a nonreducing sugar with glucoside stereochemistry. DC-SIGN staining was seen on cells with DC morphology within omental and subcutaneous adipose tissues. We conclude that high glucose disrupts C-type lectin function, potentially illuminating new perspectives on susceptibility to infectious and inflammatory disease in diabetes. Mechanisms involve competitive inhibition of carbohydrate binding within sets of defined proteins, in contrast to broadly indiscriminate, irreversible glycation of proteins. Copyright © 2010 Elsevier GmbH. All rights reserved.

DC-SIGN activation mediates the differential effects of SAP and CRP on the innate immune system and inhibits fibrosis in mice

PubMed Central

Cox, Nehemiah; Pilling, Darrell; Gomer, Richard H.

2015-01-01

Fibrosis is caused by scar tissue formation in internal organs and is associated with 45% of deaths in the United States. Two closely related human serum proteins, serum amyloid P (SAP) and C-reactive protein (CRP), strongly affect fibrosis. In multiple animal models, and in Phase 1 and Phase 2 clinical trials, SAP affects several aspects of the innate immune system to reduce fibrosis, whereas CRP appears to potentiate fibrosis. However, SAP and CRP bind the same Fcγ receptors (FcγR) with similar affinities, and why SAP and CRP have opposing effects is unknown. Here, we report that SAP but not CRP binds the receptor DC-SIGN (SIGN-R1) to affect the innate immune system, and that FcγR are not necessary for SAP function. A polycyclic aminothiazole DC-SIGN ligand and anti–DC-SIGN antibodies mimic SAP effects in vitro. In mice, the aminothiazole reduces neutrophil accumulation in a model of acute lung inflammation and, at 0.001 mg/kg, alleviates pulmonary fibrosis by increasing levels of the immunosuppressant IL-10. DC-SIGN (SIGN-R1) is present on mouse lung epithelial cells, and SAP and the aminothiazole potentiate IL-10 production from these cells. Our data suggest that SAP activates DC-SIGN to regulate the innate immune system differently from CRP, and that DC-SIGN is a target for antifibrotics. PMID:26106150

Solar Wind Earth Exchange Project (SWEEP)

DTIC Science & Technology

2016-10-28

AFRL-AFOSR-UK-TR-2016-0035 Solar Wind Earth Exchange Project 140200 Steven Sembay UNIVERSITY OF LEICESTER Final Report 10/28/2016 DISTRIBUTION A...To) 01 Sep 2014 to 31 Aug 2016 4. TITLE AND SUBTITLE Solar Wind Earth Exchange Project (SWEEP) 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-14-1...SUPPLEMENTARY NOTES 14. ABSTRACT The grant received from AFRL/AOFSR/EOARD funded the Solar Wind Earth Exchange Project (SWEEP) at Leicester University. The goal

A Technical Review of Electrochemical Techniques Applied to Microbiologically Influenced Corrosion

DTIC Science & Technology

1991-01-01

these cases. Additional problems can arise from the effects of the sweep rate which is used to determine R. according to equation (2). If the sweep ...small amplitude cyclic voltametry and ESCA.43 From the frequency dependence of the impedance data it was concluded that two relaxations were associated...the correct sweep rate and the elimination of the ohmic drop during the experiment are important considerations as discussed elsewhere. 5° The use of

A Wind Tunnel Investigation of Joined Wing Scissor Morphing

DTIC Science & Technology

2006-06-01

would use the low sweep for carrier landing and subsonic cruise, and use the high sweep for 12 supersonic flight [13]. According to Raymer [19...Wright-Patterson AFB, Ohio: Air Force Institute of Technology, 2005. 12. Katz, Joseph, Shaun Byrne, and Robert Hahl. "Stall Resistance Features of...Lifting-Body Airplane Configurations." Journal of Aircraft 2nd ser. 36 (1999): 471-474. 13. Kress, Robert W. "Variable Sweep Wing Design." AIAA 83

Effects of Wing Sweep on Boundary-layer Transition for a Smooth F-14A Wing at Mach Numbers from 0.700 to 0.825

NASA Technical Reports Server (NTRS)

Anderson, Bianca Trujillo; Meyer, Robert R., Jr.

1990-01-01

The results are discussed of the variable sweep transition flight experiment (VSTFE). The VSTFE was a natural laminar flow experiment flown on the swing wing F-14A aircraft. The main objective of the VSTFE was to determine the effects of wing sweep on boundary layer transition at conditions representative of transport aircraft. The experiment included the flight testing of two laminar flow wing gloves. Glove 1 was a cleanup of the existing F-14A wing. Glove 2, not discussed herein, was designed to provide favorable pressure distributions for natural laminar flow at Mach number (M) 0.700. The transition locations presented for glove 1 were determined primarily by using hot film sensors. Boundary layer rake data was provided as a supplement. Transition data were obtained for leading edge wing sweeps of 15, 20, 25, 30, and 35 degs, with Mach numbers ranging from 0.700 to 0.825, and altitudes ranging from 10,000 to 35,000 ft. Results show that a substantial amount of laminar flow was maintained at all the wing sweeps evaluated. The maximum transition Reynolds number of 13.7 x 10(exp 6) was obtained for the condition of 15 deg of sweep, M = 0.800, and an altitude of 20,000 ft.

Decoy receptor 3: an endogenous immunomodulator in cancer growth and inflammatory reactions.

PubMed

Hsieh, Shie-Liang; Lin, Wan-Wan

2017-06-19

Decoy receptor 3 (DcR3), also known as tumor necrosis factor receptor (TNFR) superfamily member 6b (TNFRSF6B), is a soluble decoy receptor which can neutralize the biological functions of three members of tumor necrosis factor superfamily (TNFSF): Fas ligand (FasL), LIGHT, and TL1A. In addition to 'decoy' function, recombinant DcR3.Fc is able to modulate the activation and differentiation of dendritic cells (DCs) and macrophages via 'non-decoy' action. DcR3-treated DCs skew T cell differentiation into Th2 phenotype, while DcR3-treated macrophages behave M2 phenotype. DcR3 is upregulated in various cancer cells and several inflammatory tissues, and is regarded as a potential biomarker to predict inflammatory disease progression and cancer metastasis. However, whether DcR3 is a pathogenic factor or a suppressor to attenuate inflammatory reactions, has not been discussed comprehensively yet. Because mouse genome does not have DcR3, it is not feasible to investigate its physiological functions by gene-knockout approach. However, DcR3-mediated effects in vitro are determined via overexpressing DcR3 or addition of recombinant DcR3.Fc fusion protein. Moreover, CD68-driven DcR3 transgenic mice are used to investigate DcR3-mediated systemic effects in vivo. Upregulation of DcR3 during inflammatory reactions exerts negative-feedback to suppress inflammation, while tumor cells hijack DcR3 to prevent apoptosis and promote tumor growth and invasion. Thus, 'switch-on' of DcR3 expression may be feasible for the treatment of inflammatory diseases and enhance tissue repairing, while 'switch-off' of DcR3 expression can enhance tumor apoptosis and suppress tumor growth in vivo.

DC and AC conductivity properties of bovine dentine hydroxyapatite (BDHA)

NASA Astrophysics Data System (ADS)

Dumludag, F.; Gunduz, O.; Kılıc, O.; Ekren, N.; Kalkandelen, C.; Ozbek, B.; Oktar, F. N.

2017-12-01

Bovine dentine bio-waste may be used as a potential natural source of hydroxyapatite (BDHA), thus extraction of bovine dentin hydroxyapatite (BDHA) from bio-waste is significantly important to fabricate in a simple, economically and environmentally preferable. DC and AC conductivity properties of BDHA were investigated depending on sintering temperature (1000ºC - 1300°C) in air and vacuum (<10-2 mbar) ambient at room temperature. DC conductivity measurements performed between -1 and 1 V. AC conductivity measurements performed in the frequency range of 40 Hz - 100 kHz. DC conductivity results showed that dc conductivity values of the BDHA decrease with increasing sintering temperature in air ambient. It is not observed remarkable/systematic behavior for ac conductivity depending on sintering temperature.

Oxide vapor distribution from a high-frequency sweep e-beam system

NASA Astrophysics Data System (ADS)

Chow, R.; Tassano, P. L.; Tsujimoto, N.

1995-03-01

Oxide vapor distributions have been determined as a function of operating parameters of a high frequency sweep e-beam source combined with a programmable sweep controller. We will show which parameters are significant, the parameters that yield the broadest oxide deposition distribution, and the procedure used to arrive at these conclusions. A design-of-experimental strategy was used with five operating parameters: evaporation rate, sweep speed, sweep pattern (pre-programmed), phase speed (azimuthal rotation of the pattern), profile (dwell time as a function of radial position). A design was chosen that would show which of the parameters and parameter pairs have a statistically significant effect on the vapor distribution. Witness flats were placed symmetrically across a 25 inches diameter platen. The stationary platen was centered 24 inches above the e-gun crucible. An oxide material was evaporated under 27 different conditions. Thickness measurements were made with a stylus profilometer. The information will enable users of the high frequency e-gun systems to optimally locate the source in a vacuum system and understand which parameters have a major effect on the vapor distribution.

CFD study of some factors affecting performance of HAWT with swept blades

NASA Astrophysics Data System (ADS)

Khalafallah, M. G.; Ahmed, A. M.; Emam, M. K.

2017-05-01

Most modern high-power wind turbines are horizontal axis type with straight twisted blades. Upgrading power and performance of these turbines is considered a challenge. A recent trend towards improving the horizontal axis wind turbine (HAWT) performance is to use swept blades or sweep twist adaptive blades. In the present work, the effect of blade curvature, sweep starting point and sweep direction on the wind turbine performance was investigated. The CFD simulation method was validated against available experimental data of a 0.9 m diameter HAWT. The wind turbine power and thrust coefficients at different tip speed ratios were calculated. Flow field, pressure distribution and local tangential and streamwise forces were also analysed. The results show that the downstream swept blade has the highest Cp value at design point as compared with the straight blade profile. However, the improvement in power coefficient is accompanied by a thrust increase. Results also show that the best performance is obtained when the starting blade sweeps at 25% of blade radius for different directions of sweep.

A protocol for rheological characterization of hydrogels for tissue engineering strategies.

PubMed

Zuidema, Jonathan M; Rivet, Christopher J; Gilbert, Ryan J; Morrison, Faith A

2014-07-01

Hydrogels are studied extensively for many tissue engineering applications, and their mechanical properties influence both cellular and tissue compatibility. However, it is difficult to compare the mechanical properties of hydrogels between studies due to a lack of continuity between rheological protocols. This study outlines a straightforward protocol to accurately determine hydrogel equilibrium modulus and gelation time using a series of rheological tests. These protocols are applied to several hydrogel systems used within tissue engineering applications: agarose, collagen, fibrin, Matrigel™, and methylcellulose. The protocol is outlined in four steps: (1) Time sweep to determine the gelation time of the hydrogel. (2) Strain sweep to determine the linear-viscoelastic region of the hydrogel with respect to strain. (3) Frequency sweep to determine the linear equilibrium modulus plateau of the hydrogel. (4) Time sweep with values obtained from strain and frequency sweeps to accurately report the equilibrium moduli and gelation time. Finally, the rheological characterization protocol was evaluated using a composite Matrigel™-methylcellulose hydrogel blend whose mechanical properties were previously unknown. The protocol described herein provides a standardized approach for proper analysis of hydrogel rheological properties. © 2013 Wiley Periodicals, Inc.

Sweeping Jet Optimization Studies

NASA Technical Reports Server (NTRS)

Melton, LaTunia Pack; Koklu, Mehti; Andino, Marlyn; Lin, John C.; Edelman, Louis

2016-01-01

Progress on experimental efforts to optimize sweeping jet actuators for active flow control (AFC) applications with large adverse pressure gradients is reported. Three sweeping jet actuator configurations, with the same orifice size but di?erent internal geometries, were installed on the flap shoulder of an unswept, NACA 0015 semi-span wing to investigate how the output produced by a sweeping jet interacts with the separated flow and the mechanisms by which the flow separation is controlled. For this experiment, the flow separation was generated by deflecting the wing's 30% chord trailing edge flap to produce an adverse pressure gradient. Steady and unsteady pressure data, Particle Image Velocimetry data, and force and moment data were acquired to assess the performance of the three actuator configurations. The actuator with the largest jet deflection angle, at the pressure ratios investigated, was the most efficient at controlling flow separation on the flap of the model. Oil flow visualization studies revealed that the flow field controlled by the sweeping jets was more three-dimensional than expected. The results presented also show that the actuator spacing was appropriate for the pressure ratios examined.

Uterine NK Cells Are Critical in Shaping DC Immunogenic Functions Compatible with Pregnancy Progression

PubMed Central

Freitag, Nancy; Otto, Teresa; Thijssen, Victor L. J. L.; Moschansky, Petra; von Kwiatkowski, Petra; Klapp, Burghard F.; Winterhager, Elke; Bauersachs, Stefan; Blois, Sandra M.

2012-01-01

Dendritic cell (DC) and natural killer (NK) cell interactions are important for the regulation of innate and adaptive immunity, but their relevance during early pregnancy remains elusive. Using two different strategies to manipulate the frequency of NK cells and DC during gestation, we investigated their relative impact on the decidualization process and on angiogenic responses that characterize murine implantation. Manipulation of the frequency of NK cells, DC or both lead to a defective decidual response characterized by decreased proliferation and differentiation of stromal cells. Whereas no detrimental effects were evident upon expansion of DC, NK cell ablation in such expanded DC mice severely compromised decidual development and led to early pregnancy loss. Pregnancy failure in these mice was associated with an unbalanced production of anti-angiogenic signals and most notably, with increased expression of genes related to inflammation and immunogenic activation of DC. Thus, NK cells appear to play an important role counteracting potential anomalies raised by DC expansion and overactivity in the decidua, becoming critical for normal pregnancy progression. PMID:23056436

Uterine NK cells are critical in shaping DC immunogenic functions compatible with pregnancy progression.

PubMed

Tirado-González, Irene; González, Irene Tirado; Barrientos, Gabriela; Freitag, Nancy; Otto, Teresa; Thijssen, Victor L J L; Moschansky, Petra; von Kwiatkowski, Petra; Klapp, Burghard F; Winterhager, Elke; Bauersachs, Stefan; Blois, Sandra M

2012-01-01

Dendritic cell (DC) and natural killer (NK) cell interactions are important for the regulation of innate and adaptive immunity, but their relevance during early pregnancy remains elusive. Using two different strategies to manipulate the frequency of NK cells and DC during gestation, we investigated their relative impact on the decidualization process and on angiogenic responses that characterize murine implantation. Manipulation of the frequency of NK cells, DC or both lead to a defective decidual response characterized by decreased proliferation and differentiation of stromal cells. Whereas no detrimental effects were evident upon expansion of DC, NK cell ablation in such expanded DC mice severely compromised decidual development and led to early pregnancy loss. Pregnancy failure in these mice was associated with an unbalanced production of anti-angiogenic signals and most notably, with increased expression of genes related to inflammation and immunogenic activation of DC. Thus, NK cells appear to play an important role counteracting potential anomalies raised by DC expansion and overactivity in the decidua, becoming critical for normal pregnancy progression.

A Field-Sweep/Field-Lock System for Superconducting Magnets-Application to High-Field EPR

PubMed Central

Maly, Thorsten; Bryant, Jeff; Ruben, David; Griffin, Robert G.

2007-01-01

We describe a field-lock/field-sweep system for the use in superconducting magnets. The system is based on a commercially available field mapping unit and a custom designed broad-band 1H-NMR probe. The NMR signal of a small water sample is used in a feedback loop to set and control the magnetic field to high accuracy. The current instrumental configuration allows field sweeps of ± 0.4 T and a resolution of up to 10-5 T (0.1 G) and the performance of the system is demonstrated in a high-field electron paramagnetic resonance (EPR) application. The system should also be of utility in other experiments requiring precise and reproducible sweeps of the magnetic field such as DNP, ENDOR or PELDOR. PMID:17027306

A field-sweep/field-lock system for superconducting magnets--Application to high-field EPR.

PubMed

Maly, Thorsten; Bryant, Jeff; Ruben, David; Griffin, Robert G

2006-12-01

We describe a field-lock/field-sweep system for the use in superconducting magnets. The system is based on a commercially available field mapping unit and a custom designed broad-band 1H NMR probe. The NMR signal of a small water sample is used in a feedback loop to set and control the magnetic field to high accuracy. The current instrumental configuration allows field sweeps of +/-0.4 T and a resolution of up to 10(-5) T (0.1 G) and the performance of the system is demonstrated in a high-field electron paramagnetic resonance (EPR) application. The system should also be of utility in other experiments requiring precise and reproducible sweeps of the magnetic field such as DNP, ENDOR or PELDOR.

Phase-locked loop with controlled phase slippage

DOEpatents

Mestha, Lingappa K.

1994-01-01

A system for synchronizing a first subsystem controlled by a changing frequency sweeping from a first frequency to a second frequency, with a second subsystem operating at a steady state second frequency. Trip plan parameters are calculated in advance to determine the phase relationship between the frequencies of the first subsystem and second subsystem in order to obtain synchronism at the end of the frequency sweep of the first subsystem. During the time in which the frequency of the first subsystem is sweeping from the first frequency to the second frequency, the phase locked system compares the actual phase difference with the trip plan phase difference and incrementally changes the sweep frequency in a manner so that phase lock is achieved when the first subsystem reaches a frequency substantially identical to that of the second subsystem.

Clearing Residual Planetesimals by Sweeping Secular Resonances in Transitional Disks: A Lone-planet Scenario for the Wide Gaps in Debris Disks around Vega and Fomalhaut

NASA Astrophysics Data System (ADS)

Zheng, Xiaochen; Lin, Douglas N. C.; Kouwenhoven, M. B. N.; Mao, Shude; Zhang, Xiaojia

2017-11-01

Extended gaps in the debris disks of both Vega and Fomalhaut have been observed. These structures have been attributed to tidal perturbations by multiple super-Jupiter gas giant planets. Within the current observational limits, however, no such massive planets have been detected. Here we propose a less stringent “lone-planet” scenario to account for the observed structure with a single eccentric gas giant and suggest that clearing of these wide gaps is induced by its sweeping secular resonance. With a series of numerical simulations, we show that the gravitational potential of the natal disk induces the planet to precess. At the locations where its precession frequency matches the precession frequency the planet imposes on the residual planetesimals, their eccentricity is excited by its resonant perturbation. Due to the hydrodynamic drag by the residual disk gas, the planetesimals undergo orbital decay as their excited eccentricities are effectively damped. During the depletion of the disk gas, the planet’s secular resonance propagates inward and clears a wide gap over an extended region of the disk. Although some residual intermediate-size planetesimals may remain in the gap, their surface density is too low to either produce super-Earths or lead to sufficiently frequent disruptive collisions to generate any observable dusty signatures. The main advantage of this lone-planet sweeping-secular-resonance model over the previous multiple gas giant tidal truncation scenario is the relaxed requirement on the number of gas giants. The observationally inferred upper mass limit can also be satisfied provided the hypothetical planet has a significant eccentricity. A significant fraction of solar or more massive stars bear gas giant planets with significant eccentricities. If these planets acquired their present-day kinematic properties prior to the depletion of their natal disks, their sweeping secular resonance would effectively impede the retention of neighboring planets and planetesimals over a wide range of orbital semimajor axes.

Genetic vaccines to potentiate the effective CD103+ dendritic cell-mediated cross-priming of antitumor immunity.

PubMed

Zhang, Yi; Chen, Guo; Liu, Zuqiang; Tian, Shenghe; Zhang, Jiying; Carey, Cara D; Murphy, Kenneth M; Storkus, Walter J; Falo, Louis D; You, Zhaoyang

2015-06-15

The development of effective cancer vaccines remains an urgent, but as yet unmet, clinical need. This deficiency is in part due to an incomplete understanding of how to best invoke dendritic cells (DC) that are crucial for the induction of tumor-specific CD8(+) T cells capable of mediating durable protective immunity. In this regard, elevated expression of the transcription factor X box-binding protein 1 (XBP1) in DC appears to play a decisive role in promoting the ability of DC to cross-present Ags to CD8(+) T cells in the therapeutic setting. Delivery of DNA vaccines encoding XBP1 and tumor Ag to skin DC resulted in increased IFN-α production by plasmacytoid DC (pDC) from skin/tumor draining lymph nodes and the cross-priming of Ag-specific CD8(+) T cell responses associated with therapeutic benefit. Antitumor protection was dependent on cross-presenting Batf3(+) DC, pDC, and CD8(+) T cells. CD103(+) DC from the skin/tumor draining lymph nodes of the immunized mice appeared responsible for activation of Ag-specific naive CD8(+) T cells, but were dependent on pDC for optimal effectiveness. Similarly, human XBP1 improved the capacity of human blood- and skin-derived DC to activate human T cells. These data support an important intrinsic role for XBP1 in DC for effective cross-priming and orchestration of Batf3(+) DC-pDC interactions, thereby enabling effective vaccine induction of protective antitumor immunity. Copyright © 2015 by The American Association of Immunologists, Inc.

Transcriptional and functional defects of dendritic cells derived from the MUTZ-3 leukaemia line

PubMed Central

Rasaiyaah, Jane; Noursadeghi, Mahdad; Kellam, Paul; Chain, Benjamin

2009-01-01

Dendritic cells (DC) generated from MUTZ-3, an immortalized acute myeloid leukaemia-derived cell line, have potential application as a model for the study of human DC, and as a tool with which to stimulate immunotherapeutic responses to cancer. However, the relationship of MUTZ-3 DC to their non-transformed counterparts remains incompletely understood. Immunoselected CD14+ MUTZ-3 cells were used to generate a homogeneous population of DC (M3DC). These cells had a cell surface phentoype and morphology characteristic of conventional monocyte-derived DC (MDDC). Whole genome transcriptome comparison of M3DC and MDDC however, revealed extensive differences between these two cell types. Functional ontology-based data analysis revealed three enriched clusters of genes downregulated in M3DC, with functions in pathogen recognition, DC maturation and cytokine/chemokine signalling. Downregulation of protein expression was confirmed for several of these genes. The molecular differences were accompanied by a profoundly impaired phenotypic and functional response of M3DC to microbial stimulation. The immortalized phenotype of MUTZ-3 therefore reflects not only deregulated proliferative capacity, but substantial perturbation of normal antigen-presenting cell function. These results have important implications for studies using MUTZ-3 as a model of MDDC or for cancer immunotherapy. PMID:19538250

Neisseria meningitidis expressing lgtB lipopolysaccharide targets DC-SIGN and modulates dendritic cell function.

PubMed

Steeghs, Liana; van Vliet, Sandra J; Uronen-Hansson, Heli; van Mourik, Andries; Engering, Anneke; Sanchez-Hernandez, Martha; Klein, Nigel; Callard, Robin; van Putten, Jos P M; van der Ley, Peter; van Kooyk, Yvette; van de Winkel, Jan G J

2006-02-01

Neisseria meningitidis lipopolysaccharide (LPS) has been identified as a major determinant of dendritic cell (DC) function. Here we report that one of a series of meningococcal mutants with defined truncations in the lacto-N-neotetraose outer core of the LPS exhibited unique strong adhesion and internalization properties towards DC. These properties were mediated by interaction of the GlcNAc(beta1-3)-Gal(beta1-4)-Glc-R oligosaccharide outer core of lgtB LPS with the dendritic-cell-specific ICAM-3 grabbing non-integrin (DC-SIGN) lectin receptor. Activation of DC-SIGN with this novel oligosaccharide ligand skewed T-cell responses driven by DC towards T helper type 1 activity. Thus, the use of lgtB LPS may provide a powerful instrument to selectively induce the desired arm of the immune response and potentially increase vaccine efficacy.

Process for separating carbon dioxide from flue gas using sweep-based membrane separation and absorption steps

DOEpatents

Wijmans, Johannes G.; Baker, Richard W.; Merkel, Timothy C.

2012-08-21

A gas separation process for treating flue gases from combustion processes, and combustion processes including such gas separation. The invention involves routing a first portion of the flue gas stream to be treated to an absorption-based carbon dioxide capture step, while simultaneously flowing a second portion of the flue gas across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, then passing the permeate/sweep gas to the combustor.

Effect of Foot-and-Mouth Disease Virus Infection on the Frequency, Phenotype and Function of Circulating Dendritic Cells in Cattle

PubMed Central

Sei, Janet J.; Waters, Ryan A.; Kenney, Mary; Barlow, John W.; Golde, William T.

2016-01-01

Foot-and-mouth disease virus (FMDV) is a highly contagious virus that causes one of the most devastating diseases in cloven-hoofed animals. Disease symptoms develop within 2 to 3 days of exposure and include fever and vesicular lesions on the tongue and hooves. Dendritic cells (DC) play an essential role in protective immune responses against pathogens. Therefore, investigating their role during FMDV infection would lead to a better understanding of host-pathogen interactions. In this study, following infection of cattle with FMDV, we investigated the frequency and function of conventional (cDC) and plasmacytoid DC (pDC) in blood by using multi-color flow cytometry. We show that the frequency of cDC and pDC increased following FMDV infection and peaked 3 to 4 days post-infection. During peak viremia, the cattle became lymphopenic, the expression of MHC class II molecules on cDC and pDC was dramatically down-regulated, the processing of exogenous antigen by cDC and pDC was impaired, and there was an increase in IL-10 production by DC and monocytes. Notably, after clearance of FMDV from the blood, MHC class II expression returned to pre-infection levels. Altogether, our study demonstrates that in cattle, FMDV inhibits the function of DC, thereby retarding the initiation of adaptive immune responses, potentially enhancing virus shedding during the acute phase of infection. PMID:27008425

Hardware simulation of KU-band spacecraft receiver and bit synchronizer, phase 2, volume 1. [for space shuttle

NASA Technical Reports Server (NTRS)

Lindsey, W. C.; Eisenberg, B. R.

1977-01-01

The acquisition behavior of the PN subsystem of an automatically acquiring spacecraft receiver was studied. A symbol synchronizer subsystem was constructed and integrated into the composite simulation of the receiver. The overall performance of the receiver when subjected to anomalies such as signal fades was evaluated. Potential problems associated with PN/carrier sweep interactions were investigated.

l-Tyrosine-loaded nanoparticles increase the antitumoral activity of direct electric current in a metastatic melanoma cell model

PubMed Central

de Campos, Vânia Emerich Bucco; Teixeira, Cesar Augusto Antunes; da Veiga, Venicio Feo; Júnior, Eduardo Ricci; Holandino, Carla

2010-01-01

Inhibition of tumor growth induced by treatment with direct electric current (DC) has been reported in several models. One of the mechanisms responsible for the antitumoral activity of DC is the generation of oxidative species, known as chloramines. With the aim of increasing chloramine production in the electrolytic medium and optimizing the antitumoral effects of DC, poly(ɛ-caprolactone) (PCL) nanoparticles (NPs) loaded with the amino acid tyrosine were obtained. The physical–chemical characterization showed that the NPs presented size in nanometric range and monomodal distribution. A slightly negative electrokinetic potential was also found in both blank NPs and l-tyrosine-loaded PCL NPs. The yield of the loading process was approximately 50%. Within 3 h of dissolution assay, a burst release of about 80% l-tyrosine was obtained. The in vitro cytotoxicity of DC was significantly increased when associated with l-tyrosine-loaded NPs, using a murine multidrug-resistant melanoma cell line model. This study showed that the use of the combination of nanotechnology and DC has a promising antineoplastic potential and opens a new perspective in cancer therapy. PMID:21187948

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

Garbesi, Karina; Vossos, Vagelis; Sanstad, Alan

An increasing number of energy efficient appliances operate on direct current (DC) internally, offering the potential to use DC from renewable energy systems directly and avoiding the losses inherent in converting power to alternating current (AC) and back. This paper investigates that potential for net-metered residences with on-site photovoltaics (PV) by modeling the net power draw of the ‘direct-DC house’ with respect to today’s typical configuration, assuming identical DC-internal loads. Power draws were modeled for houses in 14 U.S. cities, using hourly, simulated PV-system output and residential loads. The latter were adjusted to reflect a 33% load reduction, representative ofmore » the most efficient DC-internal technology, based on an analysis of 32 electricity end-uses. The model tested the effect of climate, electric vehicle (EV) loads, electricity storage, and load shifting on electricity savings; a sensitivity analysis was conducted to determine how future changes in the efficiencies of power system components might affect savings potential. Based on this work, we estimate that net-metered PV residences could save 5% of their total electricity load for houses without storage and 14% for houses with storage. Based on residential PV penetration projections for year 2035 obtained from the National Energy Modeling System (2.7% for the reference case and 11.2% for the extended policy case), direct-DC could save the nation 10 trillion Btu (without storage) or 40 trillion Btu (with storage). Shifting the cooling load by two hours earlier in the day (pre-cooling) has negligible benefits for energy savings. Direct-DC provides no energy savings benefits for EV charging, to the extent that charging occurs at night. However, if charging occurred during the day, for example with employees charging while at work, the benefits would be large. Direct-DC energy savings are sensitive to power system and appliance conversion efficiencies but are not significantly influenced by climate. While direct-DC for residential applications will most likely arise as a spin-off of developments in the commercial sector—because of lower barriers to market entry and larger energy benefits resulting from the higher coincidence between load and insolation—this paper demonstrates that there are substantial benefits in the residential sector as well. Among residential applications, space cooling derives the largest energy savings from being delivered by a direct-DC system. It is the largest load for the average residence on a national basis and is particularly so in high-load regions. It is also the load with highest solar coincidence.« less

DC conductivity with external magnetic field in hyperscaling violating geometry

NASA Astrophysics Data System (ADS)

Bhatnagar, Neha; Siwach, Sanjay

2018-02-01

We investigate the holographic DC conductivity of (2+1)-dimensional systems while considering hyperscaling violating geometry in bulk. We consider Einstein-Maxwell-dilaton system with two gauge fields and Liouville-type potential for dilaton. We also consider axionic fields in bulk to introduce momentum relaxation in the system. We apply an external magnetic field to study the response of the system and obtain analytic expressions for DC conductivity, Hall angle and (thermo)electric conductivity.

Acidic sweep gas with carbonic anhydrase coated hollow fiber membranes synergistically accelerates CO2 removal from blood.

PubMed

Arazawa, D T; Kimmel, J D; Finn, M C; Federspiel, W J

2015-10-01

The use of extracorporeal carbon dioxide removal (ECCO2R) is well established as a therapy for patients suffering from acute respiratory failure. Development of next generation low blood flow (<500 mL/min) ECCO2R devices necessitates more efficient gas exchange devices. Since over 90% of blood CO2 is transported as bicarbonate (HCO3(-)), we previously reported development of a carbonic anhydrase (CA) immobilized bioactive hollow fiber membrane (HFM) which significantly accelerates CO2 removal from blood in model gas exchange devices by converting bicarbonate to CO2 directly at the HFM surface. This present study tested the hypothesis that dilute sulfur dioxide (SO2) in oxygen sweep gas could further increase CO2 removal by creating an acidic microenvironment within the diffusional boundary layer adjacent to the HFM surface, facilitating dehydration of bicarbonate to CO2. CA was covalently immobilized onto poly (methyl pentene) (PMP) HFMs through glutaraldehyde activated chitosan spacers, potted in model gas exchange devices (0.0151 m(2)) and tested for CO2 removal rate with oxygen (O2) sweep gas and a 2.2% SO2 in oxygen sweep gas mixture. Using pure O2 sweep gas, CA-PMP increased CO2 removal by 31% (258 mL/min/m(2)) compared to PMP (197 mL/min/m(2)) (P<0.05). Using 2.2% SO2 acidic sweep gas increased PMP CO2 removal by 17% (230 mL/min/m(2)) compared to pure oxygen sweep gas control (P<0.05); device outlet blood pH was 7.38 units. When employing both CA-PMP and 2.2% SO2 sweep gas, CO2 removal increased by 109% (411 mL/min/m(2)) (P<0.05); device outlet blood pH was 7.35 units. Dilute acidic sweep gas increases CO2 removal, and when used in combination with bioactive CA-HFMs has a synergistic effect to more than double CO2 removal while maintaining physiologic pH. Through these technologies the next generation of intravascular and paracorporeal respiratory assist devices can remove more CO2 with smaller blood contacting surface areas. A clinical need exists for more efficient respiratory assist devices which utilize low blood flow rates (<500 mL/min) to regulate blood CO2 in patients suffering from acute lung failure. Literature has demonstrated approaches to chemically increase hollow fiber membrane (HFM) CO2 removal efficiency by shifting equilibrium from bicarbonate to gaseous CO2, through either a bioactive carbonic anhydrase enzyme coating or bulk blood acidification with lactic acid. In this study we demonstrate a novel approach to local blood acidification using an acidified sweep gas in combination with a bioactive coating to more than double CO2 removal efficiency of HFM devices. To our knowledge, this is the first report assessing an acidic sweep gas to increase CO2 removal from blood using HFM devices. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Short Communication: Inhibition of DC-SIGN-Mediated HIV-1 Infection by Complementary Actions of Dendritic Cell Receptor Antagonists and Env-Targeting Virus Inactivators.

PubMed

Pustylnikov, Sergey; Dave, Rajnish S; Khan, Zafar K; Porkolab, Vanessa; Rashad, Adel A; Hutchinson, Matthew; Fieschi, Frank; Chaiken, Irwin; Jain, Pooja

2016-01-01

The DC-SIGN receptor on human dendritic cells interacts with HIV gp120 to promote both infection of antigen-presenting cells and transinfection of T cells. We hypothesized that in DC-SIGN-expressing cells, both DC-SIGN ligands such as dextrans and gp120 antagonists such as peptide triazoles would inhibit HIV infection with potential complementary antagonist effects. To test this hypothesis, we evaluated the effects of dextran (D66), isomaltooligosaccharides (D06), and several peptide triazoles (HNG156, K13, and UM15) on HIV infection of B-THP-1/DC-SIGN cells. In surface plasmon resonance competition assays, D66 (IC50 = 35.4 μM) and D06 (IC50 = 3.4 mM) prevented binding of soluble DC-SIGN to immobilized mannosylated bovine serum albumin (BSA). An efficacious dose-dependent inhibition of DC-SIGN-mediated HIV infection in both pretreatment and posttreatment settings was observed, as indicated by inhibitory potentials (EC50) [D66 (8 μM), D06 (48 mM), HNG156 (40 μM), UM15 (100 nM), and K13 (25 nM)]. Importantly, both dextrans and peptide triazoles significantly decreased HIV gag RNA levels [D66 (7-fold), D06 (13-fold), HNG156 (7-fold), K-13 (3-fold), and UM15 (6-fold)]. Interestingly, D06 at the highest effective concentration showed a 14-fold decrease of infection, while its combination with 50 μM HNG156 showed a 26-fold decrease. Hence, these compounds can combine to inactivate the viruses and suppress DC-SIGN-mediated virus-cell interaction that as shown earlier leads to dendritic cell HIV infection and transinfection dependent on the DC-SIGN receptor.

Short Communication: Inhibition of DC-SIGN-Mediated HIV-1 Infection by Complementary Actions of Dendritic Cell Receptor Antagonists and Env-Targeting Virus Inactivators

PubMed Central

Pustylnikov, Sergey; Dave, Rajnish S.; Khan, Zafar K.; Porkolab, Vanessa; Rashad, Adel A.; Hutchinson, Matthew; Fieschi, Frank; Chaiken, Irwin

2016-01-01

Abstract The DC-SIGN receptor on human dendritic cells interacts with HIV gp120 to promote both infection of antigen-presenting cells and transinfection of T cells. We hypothesized that in DC-SIGN-expressing cells, both DC-SIGN ligands such as dextrans and gp120 antagonists such as peptide triazoles would inhibit HIV infection with potential complementary antagonist effects. To test this hypothesis, we evaluated the effects of dextran (D66), isomaltooligosaccharides (D06), and several peptide triazoles (HNG156, K13, and UM15) on HIV infection of B-THP-1/DC-SIGN cells. In surface plasmon resonance competition assays, D66 (IC50 = 35.4 μM) and D06 (IC50 = 3.4 mM) prevented binding of soluble DC-SIGN to immobilized mannosylated bovine serum albumin (BSA). An efficacious dose-dependent inhibition of DC-SIGN-mediated HIV infection in both pretreatment and posttreatment settings was observed, as indicated by inhibitory potentials (EC50) [D66 (8 μM), D06 (48 mM), HNG156 (40 μM), UM15 (100 nM), and K13 (25 nM)]. Importantly, both dextrans and peptide triazoles significantly decreased HIV gag RNA levels [D66 (7-fold), D06 (13-fold), HNG156 (7-fold), K-13 (3-fold), and UM15 (6-fold)]. Interestingly, D06 at the highest effective concentration showed a 14-fold decrease of infection, while its combination with 50 μM HNG156 showed a 26-fold decrease. Hence, these compounds can combine to inactivate the viruses and suppress DC-SIGN-mediated virus–cell interaction that as shown earlier leads to dendritic cell HIV infection and transinfection dependent on the DC-SIGN receptor. PMID:26383762

Development of the Upgraded DC Brush Gear Motor for Spacebus Platforms

NASA Technical Reports Server (NTRS)

Berning, Robert H.; Viout, Olivier

2010-01-01

The obsolescence of materials and processes used in the manufacture of traditional DC brush gear motors has necessitated the development of an upgraded DC brush gear motor (UBGM). The current traditional DC brush gear motor (BGM) design was evaluated using Six-Sigma process to identify potential design and production process improvements. The development effort resulted in a qualified UBGM design which improved manufacturability and reduced production costs. Using Six-Sigma processes and incorporating lessons learned during the development process also improved motor performance for UBGM making it a more viable option for future use as a deployment mechanism in space flight applications.

6. Historic American Buildings Survey E. W. Russell, Photographer, June ...

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

6. Historic American Buildings Survey E. W. Russell, Photographer, June 19, 1936 OLD WELL SWEEP (LEVER IN OPERATION) - Cotton Gin & Well Sweep, Cliatt Plantation, State Route 165, Cottonton, Russell County, AL

AC power generation from microbial fuel cells

NASA Astrophysics Data System (ADS)

Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

2015-11-01

Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

Parallel deterministic transport sweeps of structured and unstructured meshes with overloaded mesh decompositions

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

Pautz, Shawn D.; Bailey, Teresa S.

Here, the efficiency of discrete ordinates transport sweeps depends on the scheduling algorithm, the domain decomposition, the problem to be solved, and the computational platform. Sweep scheduling algorithms may be categorized by their approach to several issues. In this paper we examine the strategy of domain overloading for mesh partitioning as one of the components of such algorithms. In particular, we extend the domain overloading strategy, previously defined and analyzed for structured meshes, to the general case of unstructured meshes. We also present computational results for both the structured and unstructured domain overloading cases. We find that an appropriate amountmore » of domain overloading can greatly improve the efficiency of parallel sweeps for both structured and unstructured partitionings of the test problems examined on up to 10 5 processor cores.« less

Phase-locked loop with controlled phase slippage

DOEpatents

Mestha, L.K.

1994-03-29

A system for synchronizing a first subsystem controlled by a changing frequency sweeping from a first frequency to a second frequency, with a second subsystem operating at a steady state second frequency is described. Trip plan parameters are calculated in advance to determine the phase relationship between the frequencies of the first subsystem and second subsystem in order to obtain synchronism at the end of the frequency sweep of the first subsystem. During the time in which the frequency of the first subsystem is sweeping from the first frequency to the second frequency, the phase locked system compares the actual phase difference with the trip plan phase difference and incrementally changes the sweep frequency in a manner so that phase lock is achieved when the first subsystem reaches a frequency substantially identical to that of the second subsystem. 10 figures.

Pressure distribution on a 1- by 3-meter semispan wing at sweep angles from 0 deg to 40 deg in subsonic flow

NASA Technical Reports Server (NTRS)

Yip, L. P.; Shubert, G. L.

1976-01-01

A 1- by 3-meter semispan wing of taper ratio 1.0 with NACA 0012 airfoil section contours was tested in the Langley V/STOL tunnel to measure the pressure distribution at five sweep angles, 0 deg, 10 deg, 20 deg, 30 deg, and 40 deg, through an angle-of-attack range from -6 deg to 20 deg. The pressure data are presented as plots of pressure coefficients at each static-pressure tap location on the wing. Flow visualization wing-tuft photographs are also presented for a wing of 40 deg sweep. A comparison between theory and experiment using two inviscid theories and a viscous theory shows good agreement for pressure distributions, normal forces, and pitching moments for the wing at 0 deg sweep.

Parallel deterministic transport sweeps of structured and unstructured meshes with overloaded mesh decompositions

DOE PAGES

Pautz, Shawn D.; Bailey, Teresa S.

2016-11-29

Here, the efficiency of discrete ordinates transport sweeps depends on the scheduling algorithm, the domain decomposition, the problem to be solved, and the computational platform. Sweep scheduling algorithms may be categorized by their approach to several issues. In this paper we examine the strategy of domain overloading for mesh partitioning as one of the components of such algorithms. In particular, we extend the domain overloading strategy, previously defined and analyzed for structured meshes, to the general case of unstructured meshes. We also present computational results for both the structured and unstructured domain overloading cases. We find that an appropriate amountmore » of domain overloading can greatly improve the efficiency of parallel sweeps for both structured and unstructured partitionings of the test problems examined on up to 10 5 processor cores.« less

Sweep excitation with order tracking: A new tactic for beam crack analysis

NASA Astrophysics Data System (ADS)

Wei, Dongdong; Wang, KeSheng; Zhang, Mian; Zuo, Ming J.

2018-04-01

Crack detection in beams and beam-like structures is an important issue in industry and has attracted numerous investigations. A local crack leads to global system dynamics changes and produce non-linear vibration responses. Many researchers have studied these non-linearities for beam crack diagnosis. However, most reported methods are based on impact excitation and constant frequency excitation. Few studies have focused on crack detection through external sweep excitation which unleashes abundant dynamic characteristics of the system. Together with a signal resampling technique inspired by Computed Order Tracking, this paper utilize vibration responses under sweep excitations to diagnose crack status of beams. A data driven method for crack depth evaluation is proposed and window based harmonics extracting approaches are studied. The effectiveness of sweep excitation and the proposed method is experimentally validated.

Energy sweep compensation of induction accelerators

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

Sampayan, S.E.; Caporaso, G.J.; Chen, Y-J

1990-09-12

The ETA-II linear induction accelerator (LIA) is designed to drive a microwave free electron laser (FEL). Beam energy sweep must be limited to {plus minus}1% for 50 ns to limit beam corkscrew motion and ensure high power FEL output over the full duration of the beam flattop. To achieve this energy sweep requirement, we have implemented a pulse distribution system and are planning implementation of a tapered pulse forming line (PFL) in the pulse generators driving acceleration gaps. The pulse distribution system assures proper phasing of the high voltage pulse to the electron beam. Additionally, cell-to-cell coupling of beam inducedmore » transients is reduced. The tapered PFL compensates for accelerator cell and loading nonlinearities. Circuit simulations show good agreement with preliminary data and predict the required energy sweep requirement can be met.« less

Space-time correlations of fluctuating velocities in turbulent shear flows

NASA Astrophysics Data System (ADS)

Zhao, Xin; He, Guo-Wei

2009-04-01

Space-time correlations or Eulerian two-point two-time correlations of fluctuating velocities are analytically and numerically investigated in turbulent shear flows. An elliptic model for the space-time correlations in the inertial range is developed from the similarity assumptions on the isocorrelation contours: they share a uniform preference direction and a constant aspect ratio. The similarity assumptions are justified using the Kolmogorov similarity hypotheses and verified using the direct numerical simulation (DNS) of turbulent channel flows. The model relates the space-time correlations to the space correlations via the convection and sweeping characteristic velocities. The analytical expressions for the convection and sweeping velocities are derived from the Navier-Stokes equations for homogeneous turbulent shear flows, where the convection velocity is represented by the mean velocity and the sweeping velocity is the sum of the random sweeping velocity and the shear-induced velocity. This suggests that unlike Taylor’s model where the convection velocity is dominating and Kraichnan and Tennekes’ model where the random sweeping velocity is dominating, the decorrelation time scales of the space-time correlations in turbulent shear flows are determined by the convection velocity, the random sweeping velocity, and the shear-induced velocity. This model predicts a universal form of the space-time correlations with the two characteristic velocities. The DNS of turbulent channel flows supports the prediction: the correlation functions exhibit a fair good collapse, when plotted against the normalized space and time separations defined by the elliptic model.

Binding of HIV-1 gp120 to DC-SIGN Promotes ASK-1-Dependent Activation-Induced Apoptosis of Human Dendritic Cells

PubMed Central

Chan, Vera S. F.; Chung, Nancy P. Y.; Wang, Shu-Rong; Li, Zhongye; Ma, Jing; Lin, Chia-Wei; Hsieh, Ya-Ju; Chang, Kao-Ping; Kung, Sui-Sum; Wu, Yi-Chia; Chu, Cheng-Wei; Tai, Hsiao-Ting; Gao, George F.; Zheng, Bojian; Yokoyama, Kazunari K.; Austyn, Jonathan M.; Lin, Chen-Lung S.

2013-01-01

During disease progression to AIDS, HIV-1 infected individuals become increasingly immunosuppressed and susceptible to opportunistic infections. It has also been demonstrated that multiple subsets of dendritic cells (DC), including DC-SIGN(+) cells, become significantly depleted in the blood and lymphoid tissues of AIDS patients, which may contribute to the failure in initiating effective host immune responses. The mechanism for DC depletion, however, is unclear. It is also known that vast quantities of viral envelope protein gp120 are shed from maturing HIV-1 virions and form circulating immune complexes in the serum of HIV-1-infected individuals, but the pathological role of gp120 in HIV-1 pathogenesis remains elusive. Here we describe a previously unrecognized mechanism of DC death in chronic HIV-1 infection, in which ligation of DC-SIGN by gp120 sensitizes DC to undergo accelerated apoptosis in response to a variety of activation stimuli. The cultured monocyte-derived DC and also freshly-isolated DC-SIGN(+) blood DC that were exposed to either cross-linked recombinant gp120 or immune-complex gp120 in HIV(+) serum underwent considerable apoptosis after CD40 ligation or exposure to bacterial lipopolysaccharide (LPS) or pro-inflammatory cytokines such as TNFα and IL-1β. Furthermore, circulating DC-SIGN(+) DC that were isolated directly from HIV-1(+) individuals had actually been pre-sensitized by serum gp120 for activation-induced exorbitant apoptosis. In all cases the DC apoptosis was substantially inhibited by DC-SIGN blockade. Finally, we showed that accelerated DC apoptosis was a direct consequence of excessive activation of the pro-apoptotic molecule ASK-1 and transfection of siRNA against ASK-1 significantly prevented the activation-induced excessive DC death. Our study discloses a previously unknown mechanism of immune modulation by envelope protein gp120, provides new insights into HIV immunopathogenesis, and suggests potential therapeutic approaches to prevent DC depletion in chronic HIV infection. PMID:23382671

Adoptive Cell Therapy of Induced Regulatory T Cells Expanded by Tolerogenic Dendritic Cells on Murine Autoimmune Arthritis.

PubMed

Yang, Jie; Liu, Lidong; Yang, Yiming; Kong, Ning; Jiang, Xueyu; Sun, Juan; Xie, Rufeng

2017-01-01

Tolerogenic dendritic cells (tDCs) can expand TGF- β -induced regulatory T cells (iTregs); however, the therapeutic utility of these expanded iTregs in autoimmune diseases remains unknown. We sought to determine the properties of iTregs expanded by mature tolerogenic dendritic cells (iTreg mtDC ) in vitro and explore their potential to ameliorate collagen-induced arthritis (CIA) in a mouse model. After induction by TGF- β and expansion by mature tDCs (mtDCs), the phenotype and proliferation of iTreg mtDC were assessed by flow cytometry. The ability of iTregs and iTreg mtDC to inhibit CD4 + T cell proliferation and suppress Th17 cell differentiation was compared. Following adoptive transfer of iTregs and iTreg mtDC to mice with CIA, the clinical and histopathologic scores, serum levels of IFN- γ , TNF- α , IL-17, IL-6, IL-10, TGF- β and anti-CII antibodies, and the distribution of the CD4 + Th subset were assessed. Compared with iTregs, iTreg mtDC expressed higher levels of Foxp3 and suppressed CD4 + T cell proliferation and Th17 cell differentiation to a greater extent. In vivo, iTreg mtDC reduced the severity and progression of CIA more significantly than iTregs, which was associated with a modulated inflammatory cytokine profile, reduced anti-CII IgG levels, and polarized Treg/Th17 balance. This study highlights the potential therapeutic utility of iTreg mtDC in autoimmune arthritis and should facilitate the future design of iTreg immunotherapeutic strategies.

Adoptive Cell Therapy of Induced Regulatory T Cells Expanded by Tolerogenic Dendritic Cells on Murine Autoimmune Arthritis

PubMed Central

Liu, Lidong; Kong, Ning; Jiang, Xueyu; Sun, Juan; Xie, Rufeng

2017-01-01

Objective Tolerogenic dendritic cells (tDCs) can expand TGF-β-induced regulatory T cells (iTregs); however, the therapeutic utility of these expanded iTregs in autoimmune diseases remains unknown. We sought to determine the properties of iTregs expanded by mature tolerogenic dendritic cells (iTregmtDC) in vitro and explore their potential to ameliorate collagen-induced arthritis (CIA) in a mouse model. Methods After induction by TGF-β and expansion by mature tDCs (mtDCs), the phenotype and proliferation of iTregmtDC were assessed by flow cytometry. The ability of iTregs and iTregmtDC to inhibit CD4+ T cell proliferation and suppress Th17 cell differentiation was compared. Following adoptive transfer of iTregs and iTregmtDC to mice with CIA, the clinical and histopathologic scores, serum levels of IFN-γ, TNF-α, IL-17, IL-6, IL-10, TGF-β and anti-CII antibodies, and the distribution of the CD4+ Th subset were assessed. Results Compared with iTregs, iTregmtDC expressed higher levels of Foxp3 and suppressed CD4+ T cell proliferation and Th17 cell differentiation to a greater extent. In vivo, iTregmtDC reduced the severity and progression of CIA more significantly than iTregs, which was associated with a modulated inflammatory cytokine profile, reduced anti-CII IgG levels, and polarized Treg/Th17 balance. Conclusion This study highlights the potential therapeutic utility of iTregmtDC in autoimmune arthritis and should facilitate the future design of iTreg immunotherapeutic strategies. PMID:28702462

'Decoy' and 'non-decoy' functions of DcR3 promote malignant potential in human malignant fibrous histiocytoma cells.

PubMed

Toda, Mitsunori; Kawamoto, Teruya; Ueha, Takeshi; Kishimoto, Kenta; Hara, Hitomi; Fukase, Naomasa; Onishi, Yasuo; Harada, Risa; Minoda, Masaya; Kurosaka, Masahiro; Akisue, Toshihiro

2013-09-01

Decoy receptor 3 (DcR3) is a soluble secreted protein that belongs to the tumor necrosis factor receptor (TNFR) superfamily. DcR3 inhibits the Fas ligand (FasL)/Fas apoptotic pathway by binding to FasL, competitively with Fas receptor. Previous studies have reported that overexpression of DcR3 has been detected in various human malignancies and that DcR3 functions as a 'decoy' for FasL to inhibit FasL-induced apoptosis. In addition, recent studies have revealed that DcR3 has 'non-decoy' functions to promote tumor cell migration and invasion, suggesting that DcR3 may play important roles in tumor progression by decoy and non-decoy functions. We have previously reported that overexpression of DcR3 was observed in human malignant fibrous histiocytoma (MFH), however, the roles of DcR3 in MFH have not been studied. In the present study, to elucidate the roles of DcR3 in tumor progression of MFH, we examined the effects of DcR3 inhibition on cell apoptosis, migration and invasion in human MFH cells. siRNA knockdown of DcR3 enhanced the FasL-induced apoptotic activity and significantly decreased cell migration and invasion with a decrease in the activation of phosphatidylinositol 3 kinase (PI3K)/Akt and matrix metalloproteinase (MMP)-2. The findings in this study strongly suggest that DcR3 plays important roles in tumor progression of human MFH by decoy as well as non-decoy functions and that DcR3 may serve as a potent therapeutic target for human MFH.

Measurement of sheath potential by three emissive-probe methods in DC filament plasmas near a biased grid

NASA Astrophysics Data System (ADS)

Kang, In-Je; Park, In-Sun; Wackerbarth, Eugene; Bae, Min-Keun; Hershkowitz, Noah; Severn, Greg; Chung, Kyu-Sun

2017-10-01

Plasma potential structures are measured with an emissive probe near a negatively biased grid ( - 100 V , 80mm diam., 40 lines/cm) immersed in a hot filament DC discharge in Kr. Three different methods of analysis are compared: inflection point (IP), floating potential (FP) and separation point (SE) methods. The plasma device at the University of San Diego (length = 64 cm, diameter = 32 cm, source = filament DC discharge) was operated with 5 ×108

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

Generating synchrony from the asynchronous: compensation for cochlear traveling wave delays by the dendrites of individual brainstem neurons

PubMed Central

McGinley, Matthew J.; Liberman, M. Charles; Bal, Ramazan; Oertel, Donata

2012-01-01

Broadband transient sounds, such as clicks and consonants, activate a traveling wave in the cochlea. This wave evokes firing in auditory nerve fibers that are tuned to high frequencies several milliseconds earlier than in fibers tuned to low frequencies. Despite this substantial traveling wave delay, octopus cells in the brainstem receive broadband input and respond to clicks with submillisecond temporal precision. The dendrites of octopus cells lie perpendicular to the tonotopically organized array of auditory nerve fibers, placing the earliest arriving inputs most distally and the latest arriving closest to the soma. Here, we test the hypothesis that the topographic arrangement of synaptic inputs on dendrites of octopus cells allows octopus cells to compensate the traveling wave delay. We show that in mice the full cochlear traveling wave delay is 1.6 ms. Because the dendrites of each octopus cell spread across about one third of the tonotopic axis, a click evokes a soma directed sweep of synaptic input lasting 0.5 ms in individual octopus cells. Morphologically and biophysically realistic, computational models of octopus cells show that soma-directed sweeps with durations matching in vivo measurements result in the largest and sharpest somatic excitatory postsynaptic potentials (EPSPs). A low input resistance and activation of a low-voltage-activated potassium conductance that are characteristic of octopus cells are important determinants of sweep sensitivity. We conclude that octopus cells have dendritic morphologies and biophysics tailored to accomplish the precise encoding of broadband transient sounds. PMID:22764237

Analysis of the time-varying energy of brain responses to an oddball paradigm using short-term smoothed Wigner-Ville distribution.

PubMed

Tağluk, M E; Cakmak, E D; Karakaş, S

2005-04-30

Cognitive brain responses to external stimuli, as measured by event related potentials (ERPs), have been analyzed from a variety of perspectives to investigate brain dynamics. Here, the brain responses of healthy subjects to auditory oddball paradigms, standard and deviant stimuli, recorded on an Fz electrode site were studied using a short-term version of the smoothed Wigner-Ville distribution (STSW) method. A smoothing kernel was designed to preserve the auto energy of the signal with maximum time and frequency resolutions. Analysis was conducted mainly on the time-frequency distributions (TFDs) of sweeps recorded during successive trials including the TFD of averaged single sweeps as the evoked time-frequency (ETF) brain response and the average of TFDs of single sweeps as the time-frequency (TF) brain response. Also the power entropy and the phase angles of the signal at frequency f and time t locked to the stimulus onset were studied across single trials as the TF power-locked and the TF phase-locked brain responses, respectively. TFDs represented in this way demonstrated the ERP spectro-temporal characteristics from multiple perspectives. The time-varying energy of the individual components manifested interesting TF structures in the form of amplitude modulated (AM) and frequency modulated (FM) energy bursts. The TF power-locked and phase-locked brain responses provoked ERP energies in a manner modulated by cognitive functions, an observation requiring further investigation. These results may lead to a better understanding of integrative brain dynamics.

The influence of sweep on the aerodynamic loading of an oscillating NACA 0012 airfoil. Volume 1: Technical report

NASA Technical Reports Server (NTRS)

St.hilaire, A. O.; Carta, F. O.; Fink, M. R.; Jepson, W. D.

1979-01-01

Aerodynamic experiments were performed on an oscillating NACA 0012 airfoil utilizing a tunnel-spanning wing in both unswept and 30 degree swept configurations. The airfoil was tested in steady state and in oscillatory pitch about the quarter chord. The unsteady aerodynamic loading was measured using pressure transducers along the chord. Numerical integrations of the unsteady pressure transducer responses were used to compute the normal force, chord force, and moment components of the induced loading. The effects of sweep on the induced aerodynamic load response was examined. For the range of parameters tested, it was found that sweeping the airfoil tends to delay the onset of dynamic stall. Sweeping was also found to reduce the magnitude of the unsteady load variation about the mean response. It was determined that at mean incidence angles greater than 9 degrees, sweep tends to reduce the stability margin of the NACA 0012 airfoil; however, for all cases tested, the airfoil was found to be stable in pure pitch. Turbulent eddies were found to convect downstream above the upper surface and generate forward-moving acoustic waves at the trailing edge which move upstream along the lower surface.

On the single sweep processing of auditory brainstem responses: click vs. chirp stimulations and active vs. passive electrodes.

PubMed

Corona-Strauss, Farah I; Delb, Wolfgang; Bloching, Marc; Strauss, Daniel J

2008-01-01

We have recently shown that click evoked auditory brainstem responses (ABRs) single sweeps can efficiently be processed by a hybrid novelty detection system. This approach allowed for the objective detection of hearing thresholds in a fraction of time of conventional schemes, making it appropriate for the efficient implementation of newborn hearing screening procedures. It is the objective of this study to evaluate whether this approach might further be improved by different stimulation paradigms and electrode settings. In particular, we evaluate chirp stimulations which compensate the basilar-membrane dispersion and active electrodes which are less sensitive to movements. This is the first study which is directed to a single sweep processing of chirp evoked ABRs. By concentrating on transparent features and a minimum number of adjustable parameters, we present an objective comparison of click vs.chirp stimulations and active vs. passive electrodes in the ultrafast ABR detection. We show that chirp evoked brainstem responses and active electrodes might improve the single sweeps analysis of ABRs.Consequently, we conclude that a single sweep processing of ABRs for the objective determination of hearing thresholds can further be improved by the use of optimized chirp stimulations and active electrodes.

F-14 VSTFE

NASA Image and Video Library

1986-04-11

NASA 834, an F-14 Navy Tomcat, seen here in flight, was used at Dryden in 1986 and 1987 in a program known as the Variable-Sweep Transition Flight Experiment (VSTFE). This program explored laminar flow on variable sweep aircraft at high subsonic speeds. An F-14 aircraft was chosen as the carrier vehicle for the VSTFE program primarily because of its variable-sweep capability, Mach and Reynolds number capability, availability, and favorable wing pressure distribution. The variable sweep outer-panels of the F-14 aircraft were modified with natural laminar flow gloves to provide not only smooth surfaces but also airfoils that can produce a wide range of pressure distributions for which transition location can be determined at various flight conditions and sweep angles. Glove I, seen here installed on the upper surface of the left wing, was a "cleanup" or smoothing of the basic F-14 wing, while Glove II was designed to provide specific pressure distributions at Mach 0.7. Laminar flow research continued at Dryden with a research program on the NASA 848 F-16XL, a laminar flow experiment involving a wing-mounted panel with millions of tiny laser cut holes drawing off turbulent boundary layer air with a suction pump.

F-14 VSTFE - gloves #1 and #2

NASA Image and Video Library

1987-04-22

NASA 834, an F-14 Navy Tomcat, seen here in flight, was used at Dryden in 1986 and 1987 in a program known as the Variable-Sweep Transition Flight Experiment (VSTFE). This program explored laminar flow on variable sweep aircraft at high subsonic speeds. An F-14 aircraft was chosen as the carrier vehicle for the VSTFE program primarily because of its variable-sweep capability, Mach and Reynolds number capability, availability, and favorable wing pressure distribution. The variable sweep outer-panels of the F-14 aircraft were modified with natural laminar flow gloves to provide not only smooth surfaces but also airfoils that can produce a wide range of pressure distributions for which transition location can be determined at various flight conditions and sweep angles. Glove I, seen here installed on the upper surface of the left wing, was a "cleanup" or smoothing of the basic F-14 wing, while Glove II was designed to provide specific pressure distributions at Mach 0.7. Laminar flow research continued at Dryden with a research program on the NASA 848 F-16XL, a laminar flow experiment involving a wing-mounted panel with millions of tiny laser cut holes drawing off turbulent boundary layer air with a suction pump.

A neural mechanism for detecting the distance of a selected target by modulating the FM sweep rate of biosonar in echolocation of bat.

PubMed

Kamata, Eigo; Inoue, Satoru; Zheng, MeiHong; Kashimori, Yoshiki; Kambara, Takeshi

2004-01-01

Most species of bats making echolocation use frequency modulated (FM) ultrasonic pulses to measure the distance to targets. These bats detect with a high accuracy the arrival time differences between emitted pulses and their echoes generated by targets. In order to clarify the neural mechanism for echolocation, we present neural model of inferior colliculus (IC), medial geniculate body (MGB) and auditory cortex (AC) along which information of echo delay times is processed. The bats increase the downward frequency sweep rate of emitted FM pulse as they approach the target. The functional role of this modulation of sweep rate is not yet clear. In order to investigate the role, we calculated the response properties of our models of IC, MGB, and AC changing the target distance and the sweep rate. We found based on the simulations that the distance of a target in various ranges may be encoded the most clearly into the activity pattern of delay time map network in AC, when the sweep rate of FM pulse used is coincided with the observed value which the bats adopt for each range of target distance.

Numerical simulation of incidence and sweep effects on delta wing vortex breakdown

NASA Technical Reports Server (NTRS)

Ekaterinaris, J. A.; Schiff, Lewis B.

1994-01-01

The structure of the vortical flowfield over delta wings at high angles of attack was investigated. Three-dimensional Navier-Stokes numerical simulations were carried out to predict the complex leeward-side flowfield characteristics, including leading-edge separation, secondary separation, and vortex breakdown. Flows over a 75- and a 63-deg sweep delta wing with sharp leading edges were investigated and compared with available experimental data. The effect of variation of circumferential grid resolution grid resolution in the vicinity of the wing leading edge on the accuracy of the solutions was addressed. Furthermore, the effect of turbulence modeling on the solutions was investigated. The effects of variation of angle of attack on the computed vortical flow structure for the 75-deg sweep delta wing were examined. At moderate angles of attack no vortex breakdown was observed. When a critical angle of attack was reached, bubble-type vortex breakdown was found. With further increase in angle of attack, a change from bubble-type breakdown to spiral-type vortex breakdown was predicted by the numerical solution. The effects of variation of sweep angle and freestream Mach number were addressed with the solutions on a 63-deg sweep delta wing.

Chitin and Chitosan as Direct Compression Excipients in Pharmaceutical Applications

PubMed Central

Badwan, Adnan A.; Rashid, Iyad; Al Omari, Mahmoud M.H.; Darras, Fouad H.

2015-01-01

Despite the numerous uses of chitin and chitosan as new functional materials of high potential in various fields, they are still behind several directly compressible excipients already dominating pharmaceutical applications. There are, however, new attempts to exploit chitin and chitosan in co-processing techniques that provide a product with potential to act as a direct compression (DC) excipient. This review outlines the compression properties of chitin and chitosan in the context of DC pharmaceutical applications. PMID:25810109

7. Historic American Buildings Survey E. W. Russell, Photographer, June ...

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

7. Historic American Buildings Survey E. W. Russell, Photographer, June 19, 1936 OLD WELL SWEEP (LEVER IN UPRIGHT POSITION) - Cotton Gin & Well Sweep, Cliatt Plantation, State Route 165, Cottonton, Russell County, AL

Silencing of decoy receptor 3 (DcR3) expression by siRNA in pancreatic carcinoma cells induces Fas ligand-mediated apoptosis in vitro and in vivo.

PubMed

Zhou, Jian; Song, Shiduo; He, Songbin; Wang, Zhenxin; Zhang, Bing; Li, Dechun; Zhu, Dongming

2013-09-01

Decoy receptor 3 (DcR3) is abundantly expressed in human tumors and protects cells from a wide range of apoptotic stimuli. In this study, we demonstrate that DcR3 is overexpressed in pancreatic carcinoma cells, and that the pancreatic carcinoma cell lines, Panc-1 and SW1990, are resistant to Fas ligand (FasL)-mediated apoptosis. To further define the function of DcR3 in cell growth and apoptosis, we used small interfering RNA (siRNA) to knockdown the expression of the DcR3 gene in Panc-1 and SW1990 cells. Our results revealed that the silencing of DcR3 expression enhanced the inhibitory effects of FasL and reduced the capabiltiy of the cells for proliferation and colony formation in vitro. In addition, the downregulation of DcR3 modulated the cell apoptotic regulators, Fas-associated death domain (FADD), caspase‑3 and caspase‑8, thus triggering cell apoptosis. Furthermore, the knockdown of DcR3 inhibited the growth of Panc-1 tumor xenografts. Taken together, our findings indicate that DcR3 is important in cancer progression and may be a used as a potential therapeutic target for the gene therapy of pancreatic carcinoma.

Norm- and hypo-fractionated radiotherapy is capable of activating human dendritic cells.

PubMed

Kulzer, Lorenz; Rubner, Yvonne; Deloch, Lisa; Allgäuer, Andrea; Frey, Benjamin; Fietkau, Rainer; Dörrie, Jan; Schaft, Niels; Gaipl, Udo S

2014-10-01

Despite the transient immunosuppressive properties of local radiotherapy (RT), this classical treatment modality of solid tumors is capable of inducing immunostimulatory forms of tumor-cell death. The resulting 'immunotoxicity' in the tumor, but not in healthy tissues, may finally lead to immune-mediated destruction of the tumor. However, little is known about the best irradiation scheme in this setting. This study examines the immunological effects of differently irradiated human colorectal tumor cells on human monocyte-derived dendritic cells (DC). Human SW480 tumor cells were irradiated with a norm-fractionation scheme (5 × 2 Gy), a hypo-fractionated protocol (3 × 5 Gy), and with a high single irradiation dose (radiosurgery; 1 × 15 Gy). Subsequently, human immature DC (iDC) were co-incubated with supernatants (SN) of these differently treated tumor cells. Afterwards, DC were analyzed regarding the expression of maturation markers, the release of cytokines, and the potential to stimulate CD4(+) T-cells. The co-incubation of iDC with SN of tumor cells exposed to norm- or hypo-fractionated RT resulted in a significantly increased secretion of the immune activating cytokines IL-12p70, IL-8, IL-6, and TNFα, compared to iDC co-incubated with SN of tumor cells that received a high single irradiation dose or were not irradiated. In addition, DC-maturation markers CD80, CD83, and CD25 were also exclusively elevated after co-incubation with the SN of fractionated irradiated tumor cells. Furthermore, the SN of tumor cells that were irradiated with norm- or hypo-fractionated RT triggered iDC to stimulate CD4(+) T-cells not only in an allogenic, but also in an antigen-specific manner like mature DC. Collectively, these results demonstrate that norm- and hypo-fractionated RT induces a fast human colorectal tumor-cell death with immunogenic potential that can trigger DC maturation and activation in vitro. Such findings may contribute to the improvement of irradiation protocols for the most beneficial induction of anti-tumor immunity.

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.

Materials Testing on the DC-X and DC-XA

NASA Technical Reports Server (NTRS)

Smith, Dane; Carroll, Carol; Marschall, Jochen; Pallix, Joan

1997-01-01

Flight testing of thermal protection materials has been carried out over a two year period on the base heat shield of the Delta Clipper (DC-X and DC-XA), as well on a body flap. The purpose was to use the vehicle as a test bed for materials and more efficient repair or maintenance processes which would be potentially useful for application on new entry vehicles (i.e., X-33, RLV, planetary probes), as well as on the existing space shuttle orbiters. Panels containing Thermal Protection Systems (TPS) and/or structural materials were constructed either at NASA Ames Research Center or at McDonnell Douglas Aerospace (MDA) and attached between two of the four thrusters in the base heat shield of the DC-X or DC-XA. Three different panels were flown on DC-X flights 6, 7, and 8. A total of 7 panels were flown on DC-XA flights 1, 2, and 3. The panels constructed at Ames contained a variety of ceramic TPS including flexible blankets, tiles with high emissivity coatings, lightweight ceramic ablators and other ceramic composites. The MDS test panels consisted primarily of a variety of metallic composites. This report focuses on the ceramic TPS test results.

Fast sweeping methods for hyperbolic systems of conservation laws at steady state II

NASA Astrophysics Data System (ADS)

Engquist, Björn; Froese, Brittany D.; Tsai, Yen-Hsi Richard

2015-04-01

The idea of using fast sweeping methods for solving stationary systems of conservation laws has previously been proposed for efficiently computing solutions with sharp shocks. We further develop these methods to allow for a more challenging class of problems including problems with sonic points, shocks originating in the interior of the domain, rarefaction waves, and two-dimensional systems. We show that fast sweeping methods can produce higher-order accuracy. Computational results validate the claims of accuracy, sharp shock curves, and optimal computational efficiency.

High-sweeping-speed optically synchronized dual-channel terahertz-signal generator for driving a superconducting tunneling mixer and its application to active gas sensing.

PubMed

Oh, Kyoung-Hwan; Shimizu, Naofumi; Kohjiro, Satoshi; Kikuchi, Ken'ichi; Wakatsuki, Atsushi; Kukutsu, Naoya; Kado, Yuichi

2009-10-12

We propose a high-sweeping-speed optically synchronized dual-channel terahertz (THz) signal generator for an active gas-sensing system with a superconductor-insulator-superconductor (SIS) mixer. The generator can sweep a frequency range from 200 to 500 GHz at a speed of 375 GHz/s and a frequency resolution of 500 MHz. With the developed gas-sensing system, a gas-absorption-line measurement was successfully carried out with N(2)O gas in that frequency range.

Self-propelled sweeping removal of dropwise condensate

DOE PAGES

Qu, Xiaopeng; Boreyko, Jonathan; Liu, Fangjie; ...

2015-06-02

Dropwise condensation can be enhanced by superhydrophobic surfaces, on which the condensate drops spontaneously jump upon coalescence. However, the self-propelled jumping in prior reports is mostly perpendicular to the substrate. Here, we propose a substrate design with regularly spaced micropillars. Coalescence on the sidewalls of the micropillars leads to self-propelled jumping in a direction nearly orthogonal to the pillars and therefore parallel to the substrate. This in- plane motion in turn produces sweeping removal of multiple neighboring drops. The spontaneous sweeping mechanism may greatly enhance dropwise condensation in a self-sustained manner.

A MHz speed wavelength sweeping for ultra-high speed FBG interrogation

NASA Astrophysics Data System (ADS)

Kim, Gyeong Hun; Lee, Hwi Don; Eom, Tae Joong; Jeong, Myung Yung; Kim, Chang-Seok

2015-09-01

We demonstrated a MHz speed wavelength-swept fiber laser based on the active mode locking (AML) technique and applied to interrogation system of an array of fiber Bragg grating (FBG) sensors. MHz speed wavelength sweeping of wavelength-swept fiber laser can be obtained by programmable frequency modulation of the semiconductor optical amplifier (SOA) without any wavelength tunable filter. Both static and dynamic strain measurement of FBG sensors were successfully characterized with high linearity of an R-square value of 0.9999 at sweeping speed of 50 kHz.

Some Applications of Surface Raman and Infrared Spectroscopies to Mechanistic Electrochemistry Involved Adsorbed Species.

DTIC Science & Technology

1987-09-25

xidation (see text). linear sweep voltametry .12 A few representative spectra, obtained during the electrooxidation bf methanol on platium (25 4 C130H + 0.1...liner sweep veltammery. W4ktAAA.T roZ A 1AISINAC, SCUWSI CiASS#CAIOI. I Sma Ass Me* LIS) lUwas1 YA D POW 1473. gsea &M 009 0 Meel n we we t 6hff SSOem...outlined, employing optical multichannel analyzer and Fourier transform instrumentation for SERS and IRRAS, respectively, in conjunction with linear sweep

Gas separation process using membranes with permeate sweep to remove CO.sub.2 from gaseous fuel combustion exhaust

DOEpatents

Wijmans, Johannes G [Menlo Park, CA; Merkel, Timothy C [Menlo Park, CA; Baker, Richard W [Palo Alto, CA

2012-05-15

A gas separation process for treating exhaust gases from the combustion of gaseous fuels, and gaseous fuel combustion processes including such gas separation. The invention involves routing a first portion of the exhaust stream to a carbon dioxide capture step, while simultaneously flowing a second portion of the exhaust gas stream across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, then passing the permeate/sweep gas back to the combustor.

Dendritic cells (DCs) can be successfully generated from leukemic blasts in individual patients with AML or MDS: an evaluation of different methods.

PubMed

Kremser, Andreas; Dressig, Julia; Grabrucker, Christine; Liepert, Anja; Kroell, Tanja; Scholl, Nina; Schmid, Christoph; Tischer, Johanna; Kufner, Stefanie; Salih, Helmut; Kolb, Hans Jochem; Schmetzer, Helga

2010-01-01

Myeloid-leukemic cells (AML, MDS, CML) can be differentiated to leukemia-derived dendritic cell [DC (DCleu)] potentially presenting the whole leukemic antigen repertoire without knowledge of distinct leukemia antigens and are regarded as promising candidates for a vaccination strategy. We studied the capability of 6 serum-free DC culture methods, chosen according to different mechanisms, to induce DC differentiation in 137 cases of AML and 52 cases of MDS. DC-stimulating substances were cytokines ("standard-medium", "MCM-Mimic", "cytokine-method"), bacterial lysates ("Picibanil"), double-stranded RNA ["Poly (I:C)"] or a cytokine bypass method ("Ca-ionophore"). The quality/quantity of DC generated was estimated by flow cytometry studying (co) expressions of "DC"antigens, costimulatory, maturation, and blast-antigens. Comparing these methods on average 15% to 32% DC, depending on methods used, could be obtained from blast-containing mononuclear cells (MNC) in AML/MDS cases with a DC viability of more than 60%. In all, 39% to 64% of these DC were mature; 31% to 52% of leukemic blasts could be converted to DCleu and DCleu-proportions in the suspension were 2% to 70% (13%). Average results of all culture methods tested were comparable, however not every given case of AML could be differentiated to DC with 1 selected method. However performing a pre-analysis with 3 DC-generating methods (MCM-Mimic, Picibanil, Ca-ionophore) we could generate DC in any given case. Functional analyses provided proof, that DC primed T cells to antileukemia-directed cytotoxic cells, although an anti-leukemic reaction was not achieved in every case. In summary our data show that a successful, quantitative DC/DCleu generation is possible with the best of 3 previously tested methods in any given case. Reasons for different functional behaviors of DC-primed T cells must be evaluated to design a practicable DC-based vaccination strategy.

Bend sweep angle and Reynolds number effects on hemodynamics of s-shaped arteries.

PubMed

Niazmand, H; Rajabi Jaghargh, E

2010-09-01

The purpose of this study is to investigate the effects of the Reynolds number and the bend sweep angle on the blood flow patterns of S-shaped bends. The numerical simulations of steady flows in S-shaped bends with sweep angles of 45 degrees , 90 degrees , and 135 degrees are performed at Reynolds numbers of 125, 500, and 960. Hemodynamic characteristics such as secondary flows, vorticity, and axial velocity profiles are analyzed in detail. Flow patterns in S-shaped bends are strongly dependent on both Reynolds number and bend sweep angle, which can be categorized into three groups based on the first bend secondary flow effects on the transverse flow of the second bend. For low Reynolds numbers and any sweep angles, secondary flows in the second bend eliminate the first bend effects in the early sections of the second bend and therefore the axial velocity profile is consistent with the bend curvature, while for high Reynolds numbers depending on the bend sweep angles the secondary vortex pattern of the first bend may persist partially or totally throughout the second bend leading to a four-vortex secondary structure. Moreover, an interesting flow feature observed at the Reynolds number of 960 is that the secondary flow asymmetrical behavior occurred around the second bend exit and along the outflow straight section. This symmetry-breaking phenomenon which has not been reported in the previous studies is shown to be more pronounced in the 90 degrees S-shaped bend as compared to other models considered here. The probability of flow separation as one of the important flow features contributing to the onset and development of arterial wall diseases is also studied. It is observed that the second bend outer wall of gentle bends with sweep angles from 20 degrees to 30 degrees at high enough Reynolds numbers are prone to flow separation.

LWC and Temperature Effects on Ice Accretion Formation on Swept Wings at Glaze Ice Conditions

NASA Technical Reports Server (NTRS)

Vargas, Mario; Reshotko, Eli

2000-01-01

An experiment was conducted to study the effect of liquid water content and temperature on the critical distance in ice accretion formation on swept wings at glaze ice conditions. The critical distance is defined as the distance from the attachment line to tile beginning of the zone where roughness elements develop into glaze ice feathers. A baseline case of 150 mph, 25 F, 0.75 g/cu m. Cloud Liquid Water Content (LWC) and 20 micrometers in Water Droplet Median Volume Diameter (MVD) was chosen. Icing runs were performed on a NACA 0012 swept wing tip at 150 mph and MVD of 20 micrometers for liquid water contents of 0.5 g/cu m, 0.75 g/cu m, and 1.0 g/cu m, and for total temperatures of 20 F, 25 F and 30 F. At each tunnel condition, the sweep angle was changed from 0 deg to 45 deg in 5 deg increments. Casting data, ice shape tracings, and close-up photographic data were obtained. The results showed that decreasing the LWC to 0.5 g/cu m decreases the value of the critical distance at a given sweep angle compared to the baseline case, and starts the formation of complete scallops at 30 sweep angle. Increasing the LWC to 1.0 g/cu m increases the value of the critical distance compared to the baseline case, the critical distance remains always above 0 millimeters and complete scallops are not formed. Decreasing the total temperature to 20 F decreases the critical distance with respect to the baseline case and formation of complete scallops begins at 25 deg sweep angle. When the total temperature is increased to 30 F, bumps covered with roughness elements appear on the ice accretion at 25 deg and 30 deg sweep angles, large ice structures appear at 35 deg and 40 deg sweep angles, and complete scallops are formed at 45 deg sweep angle.

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.

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.

Eicosanoids: an emerging role in dendritic cell biology.

PubMed

Harizi, Hedi; Gualde, Norbert

2004-01-01

The arachidonic acid (AA)-derived metabolites, termed eicosanoids, are potent lipid mediators with a key role in immune and inflammatory responses. In the immune system, eicosanoids such as prostaglandins (PGs) and leukotrienes (LTs) are produced predominately by antigen-presenting cells (APC), including macrophages and dendritic cells (DC). DC constitute a family of bone marrow-derived professional APC that play a critical role in the induction and modulation of both innate and adaptive immunity. For many years, macrophages were considered as major producers of eicosanoids that are thought to drastically affect their function. Studies concerning the modulation of DC biology by eicosanoids show that PGs and LTs have the potential to affect the maturation, cytokine-producing capacity, Th cell-polarizing ability, and migration of DC. In addition, the development of DC from bone marrow progenitors appears to be under the control of some eicosanoids. Understanding the actions of eicosanoids and their receptors on APC functions is crucial for the generation of efficient DC for therapeutic purposes in patients. In this review, we summarize the current understanding of how DC functions are modulated by eicosanoids.

Induction of human dendritic cell maturation using transfection with RNA encoding a dominant positive toll-like receptor 4.

PubMed

Cisco, Robin M; Abdel-Wahab, Zeinab; Dannull, Jens; Nair, Smita; Tyler, Douglas S; Gilboa, Eli; Vieweg, Johannes; Daaka, Yehia; Pruitt, Scott K

2004-06-01

Maturation of dendritic cells (DC) is critical for the induction of Ag-specific immunity. Ag-loaded DC matured with LPS, which mediates its effects by binding to Toll-like receptor 4 (TLR4), induce Ag-specific CTL in vitro and in vivo in animal models. However, clinical use of LPS is limited due to potential toxicity. Therefore, we sought to mimic the maturation-inducing effects of LPS on DC by stimulating TLR4-mediated signaling in the absence of exogenous LPS. We developed a constitutively active TLR4 (caTLR4) and demonstrated that transfection of human DC with RNA encoding caTLR4 led to IL-12 and TNF-alpha secretion. Transfection with caTLR4 RNA also induced a mature DC phenotype. Functionally, transfection of DC with caTLR4 RNA enhanced allostimulation of CD4(+) T cells. DC transfected with RNA encoding the MART (Melan-A/MART-1) melanoma Ag were then used to stimulate T cells in vitro. Cotransfection of these DC with caTLR4 RNA enhanced the generation of MART-specific CTL. This CTL activity was superior to that seen when DC maturation was induced using either LPS or a standard mixture of cytokines (TNF-alpha, IL-6, IL-1beta, and PGE(2)). We conclude that transfection of DC with RNA encoding a functional signaling protein, such as caTLR4, may provide a new tool for studying TLR signaling in DC and may be a promising approach for the induction of DC maturation for tumor immunotherapy.

Characterization of Residuals Collected from Street Sweeping Operations

DOT National Transportation Integrated Search

2018-02-01

Street sweeping is a routine roadway maintenance activity conducted by the Virginia Department of Transportation (VDOT). It also provides an added benefit as a non-structural stormwater best management practice implemented by VDOT to meet total maxim...

Application of Sweeping Jet Actuators on the NASA Hump Model and Comparison with CFDVAL2004 Experiments

NASA Technical Reports Server (NTRS)

Koklu, Mehti

2017-01-01

Flow separation control over a wall-mounted hump model was studied experimentally to assess the performance of sweeping jet actuators. Results were compared to that of the 2004 CFD validation experiment (CFDVAL2004), which examined flow separation control with steady suction and unsteady zero-net-mass-flow actuators. Comparisons were carried out at low and high amplitude excitations. In addition to the active flow control methods, a passive flow control method (i.e., vortex generator) was used to complement the dataset. Steady/unsteady surface pressure measurements and surface oilflow visualization were used in the performance assessment of the actuators. The results indicated that the sweeping jet actuators are more effective than the steady suction and unsteady zero-net-mass-flow actuators. For the same momentum coefficient, the sweeping jet actuators produced more flow acceleration upstream of separation, more pressure recovery downstream, and consistently a smaller separation bubble.

Transient dynamics of a nonlinear magneto-optical rotation

NASA Astrophysics Data System (ADS)

Grewal, Raghwinder Singh; Pustelny, S.; Rybak, A.; Florkowski, M.

2018-04-01

We analyze nonlinear magneto-optical rotation (NMOR) in rubidium vapor subjected to a continuously scanned magnetic field. By varying the magnetic-field sweep rate, a transition from traditionally observed dispersivelike NMOR signals (low sweep rate) to oscillating signals (higher sweep rates) is demonstrated. The transient oscillatory behavior is studied versus light and magnetic-field parameters, revealing a strong dependence of the signals on magnetic sweep rate and light intensity. The experimental results are supported with density-matrix calculations, which enable quantitative analysis of the effect. Fitting of the signals simulated versus different parameters with a theoretically motivated curve reveals the presence of oscillatory and static components in the signals. The components depend differently on the system parameters, which suggests their distinct nature. The investigations provide insight into the dynamics of ground-state coherence generation and enable application of NMOR in detection of transient spin couplings.

Chromosome-scale selective sweeps shape Caenorhabditis elegans genomic diversity

PubMed Central

Andersen, Erik C.; Gerke, Justin P.; Shapiro, Joshua A.; Crissman, Jonathan R.; Ghosh, Rajarshi; Bloom, Joshua S.; Félix, Marie-Anne; Kruglyak, Leonid

2011-01-01

The nematode Caenorhabditis elegans is central to research in molecular, cell, and developmental biology, but nearly all of this research has been conducted on a single strain. Comparatively little is known about the population genomic and evolutionary history of this species. We characterized C. elegans genetic variation by high-throughput selective sequencing of a worldwide collection of 200 wild strains, identifying 41,188 single nucleotide polymorphisms. Unexpectedly, C. elegans genome variation is dominated by a set of commonly shared haplotypes on four of the six chromosomes, each spanning many megabases. Population-genetic modeling shows that this pattern was generated by chromosome-scale selective sweeps that have reduced variation worldwide; at least one of these sweeps likely occurred in the past few hundred years. These sweeps, which we hypothesize to be a result of human activity, have dramatically reshaped the global C. elegans population in the recent past. PMID:22286215

Critical system issues and modeling requirements: The problem of beam energy sweep in an electron linear induction accelerator

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

Turner, W.C.; Barrett, D.M.; Sampayan, S.E.

1990-08-06

In this paper we discuss system issues and modeling requirements within the context of energy sweep in an electron linear induction accelerator. When needed, particular parameter values are taken from the ETA-II linear induction accelerator at Lawrence Livermore National Laboratory. For this paper, the most important parameter is energy sweep during a pulse. It is important to have low energy sweep to satisfy the FEL resonance condition and to limit the beam corkscrew motion. It is desired to achieve {Delta}E/E = {plus minus}1% for a 50-ns flattop whereas the present level of performance is {Delta}E/E = {plus minus}1% in 10more » ns. To improve this situation we will identify a number of areas in which modeling could help increase understanding and improve our ability to design linear induction accelerators.« less

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

Evaluation and Enhancement of Carbon Dioxide Flooding Through Sweep Improvement

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

Hughes, Richard

2009-09-30

Carbon dioxide displacement is a common improved recovery method applied to light oil reservoirs (30-45{degrees}API). The economic and technical success of CO{sub 2} floods is often limited by poor sweep efficiency or large CO{sub 2} utilization rates. Projected incremental recoveries for CO{sub 2} floods range from 7% to 20% of the original oil in place; however, actual incremental recoveries range from 9% to 15% of the original oil in place, indicating the potential for significant additional recoveries with improved sweep efficiency. This research program was designed to study the effectiveness of carbon dioxide flooding in a mature reservoir to identifymore » and develop methods and strategies to improve oil recovery in carbon dioxide floods. Specifically, the project has focused on relating laboratory, theoretical and simulation studies to actual field performance in a CO{sub 2} flood in an attempt to understand and mitigate problems of areal and vertical sweep efficiency. In this work the focus has been on evaluating the status of existing swept regions of a mature CO{sub 2} flood and developing procedures to improve the design of proposed floods. The Little Creek Field, Mississippi has been studied through laboratory, theoretical, numerical and simulation studies in an attempt to relate performance predictions to historical reservoir performance to determine sweep efficiency, improve the understanding of the reservoir response to CO{sub 2} injection, and develop scaling methodologies to relate laboratory data and simulation results to predicted reservoir behavior. Existing laboratory information from Little Creek was analyzed and an extensive amount of field data was collected. This was merged with an understanding of previous work at Little Creek to generate a detailed simulation study of two portions of the field – the original pilot area and a currently active part of the field. This work was done to try to relate all of this information to an understanding of where the CO{sub 2} went or is going and how recovery might be improved. New data was also generated in this process. Production logs were run to understand where the CO{sub 2} was entering the reservoir related to core and log information and also to corroborate the simulation model. A methodology was developed and successfully tested for evaluating saturations in a cased-hole environment. Finally an experimental and theoretical program was initiated to relate laboratory work to field scale design and analysis of operations. This work found that an understanding of vertical and areal heterogeneity is crucial for understanding sweep processes as well as understanding appropriate mitigation techniques to improve the sweep. Production and injection logs can provide some understanding of that heterogeneity when core data is not available. The cased-hole saturation logs developed in the project will also be an important part of the evaluation of vertical heterogeneity. Evaluation of injection well/production well connectivities through statistical or numerical techniques were found to be as successful in evaluating CO{sub 2} floods as they are for waterfloods. These are likely to be the lowest cost techniques to evaluate areal sweep. Full field simulation and 4D seismic techniques are other possibilities but were beyond the scope of the project. Detailed simulation studies of pattern areas proved insightful both for doing a “post-mortem” analysis of the pilot area as well as a late-term, active portion of the Little Creek Field. This work also evaluated options for improving sweep in the current flood as well as evaluating options that could have been successful at recovering more oil. That simulation study was successful due to the integration of a large amount of data supplied by the operator as well as collected through the course of the project. While most projects would not have the abundance of data that Little Creek had, integration of the available data continues to be critical for both the design and evaluation stages of CO{sub 2} floods. For cases where data availability is limited, running injection/production logs and/or running cased-hole saturation tools to provide an indication of vertical heterogeneity will be important.« less

Low voltage solid-state lateral coloration electrochromic device

DOEpatents

Tracy, C.E.; Benson, D.K.; Ruth, M.R.

1984-12-21

A solid-state transition metal oxide device comprising a plurality of layers having a predisposed orientation including an electrochromic oxide layer. Conductive material including anode and cathode contacts is secured to the device. Coloration is actuated within the electrochromic oxide layer after the application of a predetermined potential between the contacts. The coloration action is adapted to sweep or dynamically extend across the length of the electrochromic oxide layer.

Low voltage solid-state lateral coloration electrochromic device

DOEpatents

Tracy, C. Edwin; Benson, David K.; Ruth, Marta R.

1987-01-01

A solid-state transition metal oxide device comprising a plurality of lay having a predisposed orientation including an electrochromic oxide layer. Conductive material including anode and cathode contacts is secured to the device. Coloration is actuated within the electrochromic oxide layer after the application of a predetermined potential between the contacts. The coloration action is adapted to sweep or dynamically extend across the length of the electrochromic oxide layer.

Oxygen Transport Membrane Reactors for Oxy-Fuel Combustion and Carbon Capture Purposes

NASA Astrophysics Data System (ADS)

Falkenstein-Smith, Ryan L.

This thesis investigates oxygen transport membrane reactors (OTMs) for the application of oxy-fuel combustion. This is done by evaluating the material properties and oxygen permeability of different OTM compositions subjected to a variety of operating conditions. The scope of this work consists of three components: (1) evaluate the oxygen permeation capabilities of perovskite-type materials for the application of oxy-fuel combustion; (2) determine the effects of dual-phase membrane compositions on the oxygen permeation performance and membrane characteristics; and (3) develop a new method for estimating the oxygen permeation performance of OTMs utilized for the application of oxy-fuel combustion. SrSc0.1Co0.9O3-delta (SSC) is selected as the primary perovskite-type material used in this research due to its reported high ionic and electronic conductive properties and chemical stability. SSC's oxygen ion diffusivity is investigated using a conductivity relaxation technique and thermogravimetric analysis. Material properties such as chemical structure, morphology, and ionic and electronic conductivity are examined by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and conductivity testing using a four-probe method, respectively. Oxygen permeation tests study the oxygen permeability OTMs under modified membrane temperatures, sweeping gas flow rates, sweeping gas compositions, membrane configurations, and membrane compositions. When utilizing a pure CO2 sweeping gas, the membrane composition was modified with the addition of Sm0.2Ce0.8O1.9-delta (SDC) at varying wt.% to improve the membranes mechanical stability. A newly developed method to evaluate the oxygen permeation performance of OTMs is also presented by fitting OTM's oxygen permeability to the methane fraction in the sweeping gas composition. The fitted data is used to estimate the overall performance and size of OTMs utilized for the application of oxy-fuel combustion. The findings from this research show that under a wide range of membrane temperatures and in a variety of atmospheres, a pure SSC OTM can achieve superior surface exchange and oxygen chemical diffusion coefficients compared to other commonly studied materials. SSC's high oxygen permeability (>1 ml.min -1.cm-2) demonstrates the material's candidacy for the application of oxy-fuel combustion. However, in the presence of rich CO 2 atmospheres, SSC shows mechanical and chemical instabilities due to the carbonate formation on the perovskite structure. The addition of SDC in the membrane composition produces a dual-phase OTM which is observed to improve the oxygen permeation flux when subjected to pure CO2 sweeping gases. When subjected to pure methane sweeping gases, dual-phase OTM compositions exhibits lower oxygen permeability compared to the single-phase SSC OTM. Despite the decline in the oxygen permeation flux, some dual-phase compositions still exhibit a high oxygen permeability, indicating their potential for the application of oxy-fuel combustion. Furthermore, a newly developed method for evaluating OTMs for the application of oxy-fuel combustion is presented in a portion of this work. This new method calculates key components such as the average oxygen permeation flux, approximate effective surface area, and the impact of additional recirculated exhaust into the incoming sweeping gas to provide a detailed understanding of OTM's application for oxy-fuel combustion. The development of this approach will aid in the evaluation of newly developed materials and create a new standard for implementing OTMs for the application of oxy-fuel combustion.

The Southern Hemisphere lower stratosphere during August and September 1987 - Analyses based on the United Kingdom Meteorological Office Global Model

NASA Technical Reports Server (NTRS)

Mckenna, D. S.; Jones, R. L.; Buckland, A. T.; Austin, J.; Tuck, A. F.; Winkler, R. H.; Chan, K. R.

1989-01-01

This paper presents a series of meteorological analyses used to aid the interpretation of the in situ Airborne Antarctic Ozone Experiment (AAOE) observations obtained aboard the ER-2 and DC-8 aircraft and examines the basis and accuracy of the analytical procedure. Maps and sections of meteorological variables derived from the UK Meteorological Office Global Model are presented for ER-2 and DC-8 flight days. It is found that analyzed temperatures and winds are generally in good agreement with AAOE observations at all levels; minor discrepancies were evident only at DC-8 altitudes. Maps of potential vorticity presented on the 428-K potential temperature surface show that the vortex is essentially circumpolar, although there are periods when major distortions are apparent.

Harnessing dendritic cells in inflammatory skin diseases

PubMed Central

Chu, Chung-Ching; Di Meglio, Paola; Nestle, Frank O.

2011-01-01

The skin immune system harbors a complex network of dendritic cells (DCs). Recent studies highlight a diverse functional specialization of skin DC subsets. In addition to generating cellular and humoral immunity against pathogens, skin DCs are involved in tolerogenic mechanisms to ensure the maintenance of immune homeostasis, as well as in pathogenesis of chronic inflammation in the skin when excessive immune responses are initiated and unrestrained. Harnessing DCs by directly targeting DC-derived molecules or selectively modulate DC subsets is a convincing strategy to tackle inflammatory skin diseases. In this review we discuss recent advances underlining the functional specialization of skin DCs and discuss the potential implication for future DC-based therapeutic strategies. PMID:21295490

Sweep and Compressibility Effects on Active Separation Control at High Reynolds Numbers

NASA Technical Reports Server (NTRS)

Seifert, Avi; Pack, LaTunia G.

2000-01-01

This paper explores the effects of compressibility, sweep and excitation location on active separation control at high Reynolds numbers. The model, which was tested in a cryogenic pressurized wind tunnel, simulates the upper surface of a 20% thick GlauertGoldschmied type airfoil at zero angle of attack. The flow is fully turbulent since the tunnel sidewall boundary layer flows over the model. Without control, the flow separates at the highly convex area and a large turbulent separation bubble is formed. Periodic excitation is applied to gradually eliminate the separation bubble. Two alternative blowing slot locations as well as the effect of compressibility, sweep and steady suction or blowing were studied. During the test the Reynolds numbers ranged from 2 to 40 million and Mach numbers ranged from 0.2 to 0.7. Sweep angles were 0 and 30 deg. It was found that excitation must be introduced slightly upstream of the separation region regardless of the sweep angle at low Mach number. Introduction of excitation upstream of the shock wave is more effective than at its foot. Compressibility reduces the ability of steady mass transfer and periodic excitation to control the separation bubble but excitation has an effect on the integral parameters, which is similar to that observed in low Mach numbers. The conventional swept flow scaling is valid for fully and even partially attached flow, but different scaling is required for the separated 3D flow. The effectiveness of the active control is not reduced by sweep. Detailed flow field dynamics are described in the accompanying paper.

Sweep and Compressibility Effects on Active Separation Control at High Reynolds Numbers

NASA Technical Reports Server (NTRS)

Seifert, Avi; Pack, LaTunia G.

2000-01-01

This paper explores the effects of compressibility, sweep and excitation location on active separation control at high Reynolds numbers. The model, which was tested in a cryogenic pressurized wind tunnel, simulates the upper surface of a 20% thick Glauert Goldschmied type airfoil at zero angle of attack. The flow is fully turbulent since the tunnel sidewall boundary layer flows over the model. Without control, the flow separates at the highly convex area and a large turbulent separation bubble is formed. Periodic excitation is applied to gradually eliminate the separation bubble. Two alternative blowing slot locations as well as the effect of compressibility, sweep and steady suction or blowing were studied. During the test the Reynolds numbers ranged from 2 to 40 million and Mach numbers ranged from 0.2 to 0.7. Sweep angles were 0 and 30 deg. It was found that excitation must be introduced slightly upstream of the separation region regardless of the sweep angle at low Mach number. Introduction of excitation upstream of the shock wave is more effective than at its foot. Compressibility reduces the ability of steady mass transfer and periodic excitation to control the separation bubble but excitation has an effect on the integral parameters, which is similar to that observed in low Mach numbers. The conventional swept flow scaling is valid for fully and even partially attached flow, but different scaling is required for the separated 3D flow. The effectiveness of the active control is not reduced by sweep. Detailed flow field dynamics are described in the accompanying paper.

Summary of NASA Support of the F-111 Development Program. Part 1; December 1962 - December 1965

NASA Technical Reports Server (NTRS)

1966-01-01

The F-111 is a biservice, multimission, tactical aircraft being developed for the Air Force and Navy by General Dynamics and Grumman. The general arrangement of the F-111 is shown in figure 1. This aircraft, through the use of the "variable sweep wing" concept, offers the possibility of combining a wide range of mission capabilities into a single aircraft. The F-111 is a direct outgrowth of the Langley Research Center's variable sweep research which began in 1947. The early research culminated in the X-5 variable sweep research airplane which demonstrated the advantage and feasibility of in-flight sweep variation The X-5 utilized the translating wing concept to offset the longitudinal stability variation with sweep changes. Later Langley research beginning in 1958 resulted in the "outboard pivot" concept which eliminated the need for wing translation and led .to the TFX (F-111) concept. A chronology of the NACA/NASA variable sweep research effort and direct suport of the TFX up to the awarding of the contract to General Dynamics/Grumman on November 24, 1962, is presented in refer'ence 1. Since the awarding of the contract, the Langley, Ames, Lewis, and Flight Research Centers have been actively supporting the F-111 development program. Because of the strong NASA interest in this aircraft and the large magnitude of NASA support involved, it was felt desirable to document this support. The purpose of this paper therefore is to present a brief summary of the NASA support, in chronological order, through December 1965, beginning with the awarding of the contract in November 1962.

Three pillars for achieving quantum mechanical molecular dynamics simulations of huge systems: Divide-and-conquer, density-functional tight-binding, and massively parallel computation.

PubMed

Nishizawa, Hiroaki; Nishimura, Yoshifumi; Kobayashi, Masato; Irle, Stephan; Nakai, Hiromi

2016-08-05

The linear-scaling divide-and-conquer (DC) quantum chemical methodology is applied to the density-functional tight-binding (DFTB) theory to develop a massively parallel program that achieves on-the-fly molecular reaction dynamics simulations of huge systems from scratch. The functions to perform large scale geometry optimization and molecular dynamics with DC-DFTB potential energy surface are implemented to the program called DC-DFTB-K. A novel interpolation-based algorithm is developed for parallelizing the determination of the Fermi level in the DC method. The performance of the DC-DFTB-K program is assessed using a laboratory computer and the K computer. Numerical tests show the high efficiency of the DC-DFTB-K program, a single-point energy gradient calculation of a one-million-atom system is completed within 60 s using 7290 nodes of the K computer. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Procedures for waste management from street sweeping and stormwater systems.

DOT National Transportation Integrated Search

2016-05-01

Street sweeping and storm water system cleaning activities are conducted regularly by ODOT to comply with NPDES permit requirements and to ensure roadway safety. Once collected, these materials are classified as solid waste and require cost-effective...

12 CFR 344.6 - Notification by agreement; alternative forms and times of notification.

Code of Federal Regulations, 2011 CFR

2011-01-01

....5. The bank may charge a reasonable fee for providing the information described in § 344.5. (d) Cash management sweep accounts. A bank effecting a securities transaction for a cash management sweep account...

A simple ERP method for quantitative analysis of cognitive workload in myoelectric prosthesis control and human-machine interaction.

PubMed

Deeny, Sean; Chicoine, Caitlin; Hargrove, Levi; Parrish, Todd; Jayaraman, Arun

2014-01-01

Common goals in the development of human-machine interface (HMI) technology are to reduce cognitive workload and increase function. However, objective and quantitative outcome measures assessing cognitive workload have not been standardized for HMI research. The present study examines the efficacy of a simple event-related potential (ERP) measure of cortical effort during myoelectric control of a virtual limb for use as an outcome tool. Participants trained and tested on two methods of control, direct control (DC) and pattern recognition control (PRC), while electroencephalographic (EEG) activity was recorded. Eighteen healthy participants with intact limbs were tested using DC and PRC under three conditions: passive viewing, easy, and hard. Novel auditory probes were presented at random intervals during testing, and significant task-difficulty effects were observed in the P200, P300, and a late positive potential (LPP), supporting the efficacy of ERPs as a cognitive workload measure in HMI tasks. LPP amplitude distinguished DC from PRC in the hard condition with higher amplitude in PRC, consistent with lower cognitive workload in PRC relative to DC for complex movements. Participants completed trials faster in the easy condition using DC relative to PRC, but completed trials more slowly using DC relative to PRC in the hard condition. The results provide promising support for ERPs as an outcome measure for cognitive workload in HMI research such as prosthetics, exoskeletons, and other assistive devices, and can be used to evaluate and guide new technologies for more intuitive HMI control.

Uncarinic Acid C Isolated from Uncaria rhynchophylla Induces Differentiation of Th1-Promoting Dendritic Cells Through TLR4 Signaling

PubMed Central

Kim, Kyu Sik; Pham, Thanh Nhan Nguyen; Jin, Chun-Ji; Umeyama, Akemi; Shoji, Noboru; Hashimoto, Toshihiro; Lee, Je-Jung; Takei, Masao

2011-01-01

Uncarinic acid C (URC) is triterpene isolated from Uncaria rhynchophylla and is a pharmacologically active substance. The induction of dendritic cells (DC) is critical for the induction of Ag-specific T lymphocyte responses and may be essential for the development of human vaccines relying on T cell immunity. DC might be a potential target for URC. We demonstrate that URC activates human DC as documented by phenotypic and functional maturation, and altered cytokine production. The expression of CD1a, CD38, CD40, CD54, CD80, CD83, CD86, HLA-DR and CCR7 on URC-primed DC was enhanced. The production of IL-12p70 by URC-primed DC was higher than that of lipopolysaccharide (LPS)-primed DC. The production of IL-12p70 by URC-primed DC was inhibited by the anti-Toll-like receptor 4 (TLR4) monoclonal antibody (mAb), but partially abolished by anti-TLR2 mAb. mRNA coding for TLR2 and TLR4 was expressed in URC-primed DC. URC-primed DC induced the NF-κB transcription factor. Naïve T cells co-cultured with URC-primed DC turned into typical Th1 cells that produced large quantities of IFN-γ depending on IL-12 secretion. URC enhanced the T cell stimulatory capacity in an allo MLR. In the cytotoxic T-lymphocyte assay (CTL) assay, DNA fragmentation assay and 51Cr release on URC-primed DC were more augmented than that of TNF-α-primed DC. DC matured with URC had an intermediate migratory capacity towards CCL19 and CCL21. These results suggest that URC modulates DC function in a fashion that favors Th1 polarization via the activation of IL-12p70 dependent on TLR4 signaling, and may be used on DC-based vaccine for cancer immunotherapy. PMID:21499439

Uncarinic Acid C Isolated from Uncaria rhynchophylla Induces Differentiation of Th1-Promoting Dendritic Cells Through TLR4 Signaling.

PubMed

Kim, Kyu Sik; Pham, Thanh Nhan Nguyen; Jin, Chun-Ji; Umeyama, Akemi; Shoji, Noboru; Hashimoto, Toshihiro; Lee, Je-Jung; Takei, Masao

2011-02-28

Uncarinic acid C (URC) is triterpene isolated from Uncaria rhynchophylla and is a pharmacologically active substance. The induction of dendritic cells (DC) is critical for the induction of Ag-specific T lymphocyte responses and may be essential for the development of human vaccines relying on T cell immunity. DC might be a potential target for URC. We demonstrate that URC activates human DC as documented by phenotypic and functional maturation, and altered cytokine production. The expression of CD1a, CD38, CD40, CD54, CD80, CD83, CD86, HLA-DR and CCR7 on URC-primed DC was enhanced. The production of IL-12p70 by URC-primed DC was higher than that of lipopolysaccharide (LPS)-primed DC. The production of IL-12p70 by URC-primed DC was inhibited by the anti-Toll-like receptor 4 (TLR4) monoclonal antibody (mAb), but partially abolished by anti-TLR2 mAb. mRNA coding for TLR2 and TLR4 was expressed in URC-primed DC. URC-primed DC induced the NF-κB transcription factor. Naïve T cells co-cultured with URC-primed DC turned into typical Th1 cells that produced large quantities of IFN-γ depending on IL-12 secretion. URC enhanced the T cell stimulatory capacity in an allo MLR. In the cytotoxic T-lymphocyte assay (CTL) assay, DNA fragmentation assay and (51)Cr release on URC-primed DC were more augmented than that of TNF-α-primed DC. DC matured with URC had an intermediate migratory capacity towards CCL19 and CCL21. These results suggest that URC modulates DC function in a fashion that favors Th1 polarization via the activation of IL-12p70 dependent on TLR4 signaling, and may be used on DC-based vaccine for cancer immunotherapy.

Wall charging of a helicon antenna wrapped plasma filled dielectric tube

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

Barada, Kshitish K., E-mail: kbarada@physics.ucla.edu; Chattopadhyay, P. K., E-mail: pkchatto@ipr.res.in; Ghosh, J.

2015-01-15

Dielectric wall charging of a cylindrical glass wall surrounded by a helicon antenna of 18 cm length is measured in a linear helicon plasma device with a diverging magnetic field. The ions because of their lesser mobility do not respond to the high frequency electric field and the electrons charge the wall to a negative DC potential also known as the DC self-bias. The wall potential in this device is characterized for different neutral pressure, magnetic field, and radio frequency (RF) power. Axial variation of wall potential shows higher self-bias potentials near the antenna rings. Ion magnetization in the source chambermore » increases both wall charging and plasma potential of the source due to confinement.« less

CD10 and osteopontin expression in dentigerous cyst and ameloblastoma.

PubMed

Masloub, Shaimaa M; Abdel-Azim, Adel M; Elhamid, Ehab S Abd

2011-05-24

To investigate the expression of CD10 and osteopontin in dentigerous cyst and ameloblastoma and to correlate their expression with neoplastic potentiality of dentigerous cyst and local invasion and risk of local recurrence in ameloblastoma. CD10 and osteopontin expression was studied by means of immunohistochemistry in 9 cases of dentigerous cysts (DC) and 17 cases of ameloblastoma. There were 7 unicystic ameloblastoma (UCA) and 10 multicystic ameloblastoma (MCA). Positive cases were included in the statistical analysis, carried on the tabulated data using the Open Office Spreadsheet 3.2.1 under Linux operating system. Analysis of variance and correlation studies were performed using "R" under Linux operating system (R Development Core Team (2010). Tukey post-hoc test was also performed as a pair-wise test. The significant level was set at 0.05. High CD10 and osteopontin expression was observed in UCA and MCA, and low CD10 and osteopontin expression was observed in DC. Significant correlation was seen between CD10 and osteopontin expression and neoplastic potentiality of DC and local invasion and risk of recurrences in ameloblastoma. In DC, high CD10 and osteopontin expression may indicate the neoplastic potentiality of certain areas. In UCA & MCA, high CD10 and osteopontin expression may identify areas with locally invasive behavior and high risk of recurrence.

Autologous tolerogenic dendritic cells for rheumatoid and inflammatory arthritis

PubMed Central

Bell, G M; Anderson, A E; Diboll, J; Reece, R; Eltherington, O; Harry, R A; Fouweather, T; MacDonald, C; Chadwick, T; McColl, E; Dunn, J; Dickinson, A M; Hilkens, C M U; Isaacs, John D

2017-01-01

Objectives To assess the safety of intra-articular (IA) autologous tolerogenic dendritic cells (tolDC) in patients with inflammatory arthritis and an inflamed knee; to assess the feasibility and acceptability of the approach and to assess potential effects on local and systemic disease activities. Methods An unblinded, randomised, controlled, dose escalation Phase I trial. TolDC were differentiated from CD14+ monocytes and loaded with autologous synovial fluid as a source of autoantigens. Cohorts of three participants received 1×106, 3×106 or 10×106 tolDC arthroscopically following saline irrigation of an inflamed (target) knee. Control participants received saline irrigation only. Primary outcome was flare of disease in the target knee within 5 days of treatment. Feasibility was assessed by successful tolDC manufacture and acceptability via patient questionnaire. Potential effects on disease activity were assessed by arthroscopic synovitis score, disease activity score (DAS)28 and Health Assessment Questionnaire (HAQ). Immunomodulatory effects were sought in peripheral blood. Results There were no target knee flares within 5 days of treatment. At day 14, arthroscopic synovitis was present in all participants except for one who received 10×106 tolDC; a further participant in this cohort declined day 14 arthroscopy because symptoms had remitted; both remained stable throughout 91 days of observation. There were no trends in DAS28 or HAQ score or consistent immunomodulatory effects in peripheral blood. 9 of 10 manufactured products met quality control release criteria; acceptability of the protocol by participants was high. Conclusion IA tolDC therapy appears safe, feasible and acceptable. Knee symptoms stabilised in two patients who received 10×106 tolDC but no systemic clinical or immunomodulatory effects were detectable. Trial registration number NCT01352858. PMID:27117700

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.

Cold atmospheric plasma jet in an axial DC electric field

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

Lin, Li, E-mail: lilin@gwu.edu, E-mail: keidar@gwu.edu; Keidar, Michael, E-mail: lilin@gwu.edu, E-mail: keidar@gwu.edu

2016-08-15

Cold atmospheric plasma (CAP) jet is currently intensively investigated as a tool for new and potentially transformative cancer treatment modality. However, there are still many unknowns about the jet behavior that requires attention. In this paper, a helium CAP jet is tested in an electrostatic field generated by a copper ring. Using Rayleigh microwave scattering method, some delays of the electron density peaks for different ring potentials are observed. Meanwhile, a similar phenomenon associated with the bullet velocity is found. Chemical species distribution along the jet is analyzed based on the jet optical emission spectra. The spectra indicate that amore » lower ring potential, i.e., lower DC background electric field, can increase the amount of excited N{sub 2}, N{sub 2}{sup +}, He, and O in the region before the ring, but can decrease the amount of excited NO and HO almost along the entire jet. Combining all the results above, we discovered that an extra DC potential mainly affects the temporal plasma jet properties. Also, it is possible to manipulate the chemical compositions of the jet using a ring with certain electric potentials.« less

Habitat management of organic vineyard in Northern Italy: the role of cover plants management on arthropod functional biodiversity.

PubMed

Burgio, G; Marchesini, E; Reggiani, N; Montepaone, G; Schiatti, P; Sommaggio, D

2016-12-01

The effect of cover plants on arthropod functional biodiversity was investigated in a vineyard in Northern Italy, through a 3-year field experiment. The following six ground cover plants were tested: Sweet Alyssum; Phacelia; Buckwheat; Faba Bean; Vetch and Oat; control. Arthropods were sampled using different techniques, including collection of leaves, vacuum sampling and sweeping net. Ground cover plant management significantly affected arthropod fauna, including beneficial groups providing ecosystem services like biological control against pests. Many beneficial groups were attracted by ground cover treatments in comparison with control, showing an aggregative numerical response in the plots managed with some of the selected plant species. Alyssum, Buckwheat and 'Vetch and Oat' mixture showed attractiveness on some Hymenoptera parasitoid families, which represented 72.3% of the insects collected by sweeping net and 45.7 by vacuum sampling. Phytoseiidae mites showed a significant increase on leaves of the vineyard plots managed with ground covers, in comparison with control, although they did not show any difference among the treatments. In general, the tested ground cover treatments did not increase dangerous Homoptera populations in comparison with control, with the exception of Alyssum. The potential of ground cover plant management in Italian vineyards is discussed: the overall lack of potential negative effects of the plants tested, combined with an aggregative numerical response for many beneficials, seems to show a potential for their use in Northern Italy vineyards.

The Concept and Economics of RDF-3 (Refuse Derived Fuel) Utilization in a Navy Size Pulverized Coal Boiler.

DTIC Science & Technology

1983-05-01

ELE ENTM. PRO ECT. TASK AREA 4 WORK LIN IT kuldElS WASTE ENERGY TECHNOLOGY CORPORATION Y0817-006-01-211 Bedford, MA 01730 I P CONTROLLING OFFICE NAME...Louis Miller-Hoft. 150 Augers 1 50 Missouri Live bottom, Tons TPH rectangular Ames Atlas. 500 Sweep bucket 4 14 Iowa Tons and drag con - TPH veyor Each...Monroe County a. Trailers 17 Hyd. Rams NewYork Tons Each b. Atlas 450 Sweep bucket 8 6 Tons and drag con - TPH veyor Each . Milwaukee Atlas 900 Sweep

Adiabatic description of long range frequency sweeping

NASA Astrophysics Data System (ADS)

Breizman, Boris; Nyqvist, Robert; Lilley, Matthew

2012-10-01

A theoretical framework is developed to describe long range frequency sweeping events in the 1D electrostatic bump-on-tail model with fast particle sources and collisions. The model includes three collision operators (Krook, drag (dynamical friction) and velocity space diffusion), and allows for a general shape of the fast particle distribution function. The behavior of phase space holes and clumps is analyzed, and the effect of particle trapping due to separatrix expansion is discussed. With a fast particle distribution function whose slope decays above the resonant phase velocity, hooked frequency sweeping is found for holes in the presence of drag collisions alone.

Brady's Geothermal Field DAS Vibroseis Data

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

Kurt Feigl

2016-03-25

The submitted data correspond to the monitored vibrations caused by a vibroseis seismically exciting the ground in the vertical direction and captured by the DAS horizontal and vertical arrays during the PoroTomo Experiment. The data also include a file with the acceleration record at the Vibroseis. Vibroseis Sweep Details: Sweep on location T84 Stage 4 (Mode P 60 s long record ) Time: 2016-03-25 14:01:15 (UTC) Location: 39.80476089N, -119.0027625W Elevation: 1272.0M (on ground surface at the site) Sweep length: 20 seconds Frequencies: 5 Hz to 20 Hz

Nonlinear femtosecond pump-probe spectroscopy using a power-encoded soliton delay line.

PubMed

Saint-Jalm, Sarah; Andresen, Esben Ravn; Bendahmane, Abdelkrim; Kudlinski, Alexandre; Rigneault, Hervé

2016-01-01

We show femtosecond time-resolved nonlinear pump-probe spectroscopy using a fiber soliton as the probe pulse. Furthermore, we exploit soliton dynamics to record an entire transient trace with a power-encoded delay sweep. The power-encoded delay line takes advantage of the dependency of the soliton trajectory in the (λ,z) space upon input power; the difference in accumulated group delay between trajectories converts a fast power sweep into a fast delay sweep. We demonstrate the concept by performing transient absorption spectroscopy in a test sample and validate it against a conventional pump-probe setup.

Flight and swarming behaviour of Culicoides species (Diptera: Ceratopogonidae) on a livestock farm in Northern Spain.

PubMed

Gonza Lez, Mikel; Alarco N-Elbal, Pedro M; Venter, Gert J; Lo Pez, Sergio

2017-06-30

The efficacy of sweep nets and a CDC white light-suction trap for the sampling of Culicoides species (Diptera: Ceratopogonidae) were compared on a livestock farm in Northern Spain during the Summer of 2013. A total of 6,082 specimens representing 26 species were collected with sweep nets in 4 areas at di erent heights (ground level, 1.5 m, and 3 m), and 8,463 specimens representing 28 species with a single white light trap. Eight species - Culicoides brunnicans, Culicoides punctatus, Culicoides obsoletus/Culicoides scoticus, Culicoides lupicaris, Culcoides picturatus, Culicoides achrayi, and Culicoides simulator - were dominant and accounted for 97.4% and 97.2% of the total specimens collected with both methods, sweep nets, and light traps, respectively. The sex ratios with sweep netting and light trapping were strongly female biased (78.4% and 97.1%, respectively). Nulliparous and parous females were predominantly captured with both methods. A high percentage (17%) of gravid females was, however, captured on manure at ground level while sweeping. Searches for male swarms revealed the presence of several C. punctatus swarms consisting of 26 to 196 males and 3 swarms of C. obsoletus that ranged from 1 to 12 males in size. This study suggested that both methods are suitable and complementary tools for Culicoides sampling.

Simulations of magnetic hysteresis loops at high temperatures

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

Plumer, M. L.; Whitehead, J. P.; Fal, T. J.

2014-09-28

The kinetic Monte-Carlo algorithm as well as standard micromagnetics are used to simulate MH loops of high anisotropy magnetic recording media at both short and long time scales over a wide range of temperatures relevant to heat-assisted magnetic recording. Microscopic parameters, common to both methods, were determined by fitting to experimental data on single-layer FePt-based media that uses the Magneto-Optic Kerr effect with a slow sweep rate of 700 Oe/s. Saturation moment, uniaxial anisotropy, and exchange constants are given an intrinsic temperature dependence based on published atomistic simulations of FePt grains with an effective Curie temperature of 680 K. Ourmore » results show good agreement between micromagnetics and kinetic Monte Carlo results over a wide range of sweep rates. Loops at the slow experimental sweep rates are found to become more square-shaped, with an increasing slope, as temperature increases from 300 K. These effects also occur at higher sweep rates, typical of recording speeds, but are much less pronounced. These results demonstrate the need for accurate determination of intrinsic thermal properties of future recording media as input to micromagnetic models as well as the sensitivity of the switching behavior of thin magnetic films to applied field sweep rates at higher temperatures.« less

Wind-tunnel investigation of several high aspect-ratio supercritical wing configurations on a wide-body-type fuselage

NASA Technical Reports Server (NTRS)

Bartlett, D. W.

1977-01-01

An investigation was conducted in the Langley 8-foot transonic pressure tunnel on two aspect-ratio 11.95 supercritical wings that were tested in combination with a representative wide-body-type fuselage. The two supercritical wings have identical planforms for equal sweep angles and differ only in thickness. Each wing was tested at quarter-chord sweep angles of 27 deg and 30 deg. At the higher sweep angle, the aspect ratio is reduced to 11.36. At 27 deg of quarter-chord sweep, the thicker supercritical wing (SCW-1) has maximum streamwise thickness-to-chord ratios of 0.16 at the wing-fuselage juncture, 0.14 at the planform break station, and 0.12 at the tip. The thinner wing (SCW-2) has maximum streamwise thickness-to-chord ratios of 0.144, 0.12, and 0.10 at the same stations respectively. Tests were also conducted on the thinner supercritical wing at the 27 deg sweep angle with a 15.24 cm (6.0 in.) shorter span which results in an aspect ratio of 10.25. For comparison, data were obtained on a current wide-body transport wing (AR=7) that was tested on the same fuselage used with the supercritical wings.

7,8-Dihydroxycoumarin exerts antitumor potential on DMBA-induced mammary carcinogenesis by inhibiting ERα, PR, EGFR, and IGF1R: involvement of MAPK1/2-JNK1/2-Akt pathway.

PubMed

Kumar, Abhishek; Sunita, Priyashree; Jha, Shivesh; Pattanayak, Shakti P

2018-05-01

Breast cancer (BC) is a persistent and impulsive metabolic disorder with the highest prevalence in women, worldwide. 7,12-Dimethylbenz(a)anthracene (DMBA) is a potent polyaromatic hydrocarbon (PAH)-based carcinogen producing mammary carcinomas in rats resembling the human hormone-dependent BC. 7,8-Dihydroxycoumarin (78DC) is a coumarin derivative that possesses diversified and favorable pharmacology profile to be considered in anticancer research against various malignancies. The present study was intended to investigate the antiproliferative and chemotherapeutic potentials of 78DC (20, 40, and 80 mg/kg BW) against DMBA (20 mg in olive oil)-induced mammary carcinoma Sprague-Dawley rats. We established the in silico approach for evaluation of the effect of 78DC on hormonal (estrogen receptor-α (ERα), progesterone receptor (PR)), growth factor receptors (EGFR and IGFR), 17β-hydroxysteroid dehydrogenase type 1 (17β-HD1), and aromatase. Effect of 78DC on estrogen synthesis, tumor growth, proliferation markers (Ki-67 and PCNA), cytokines (IL-10, IL-1β, IL-12), chemokine (MCP-1), and cellular expressions of ERα, PR, EGFR, IGF1R, p-MAPK1/2, p-JNK1/2, p-Akt, 17β-HD1, and aromatase was evaluated in mammary carcinoma bearing SD rats. DMBA induces large tumor burden and histological alterations in mammary gland with a subsequent increase in ERα, PR, EGFR, IGF1R, Ki-67, proliferating cell nuclear antigen (PCNA ), cytokines, and chemokine expressions. This was also correlated with the changes in rapid cell differentiation and proliferation. In contrast, 78DC treatment to the cancer-bearing animals abbreviated these changes and revealed to possess antitumorigenic and antiproliferative potentials. Further, a significant decrease in expressions of ERα, PR, EGFR, IGFR, p-MAPK1/2, p-JNK1/2, p-Akt, 17β-HD1, and aromatase signifies a reduction in estrogen sensitivity and secondary signaling pathways that may contribute to the prevention of tumor growth. The current findings revealed that 78DC potentially reduce cancer cell proliferation and reverted mammary cancer-induced changes in experimental animals in a dose-dependent manner.

DC power limitation of the heterojunction bipolar transistor with dot geometry: Effect of base potential distribution on thermal runaway

NASA Astrophysics Data System (ADS)

Liou, L. L.; Jenkins, T.; Huang, C. I.

1997-06-01

The d.c. power limitation of a conventional HBT with dot geometry was studied theoretically using combined electro-thermal and transmission line models. In most cases, the thermal runaway occurs at a power level lower than that set by the intrinsic electronic property of the device. The dependence of the d.c. thermal runaway threshold power density, Pmax, on the emitter dot radius and emitter ballast resistance was calculated. Increasing emitter dot radius lowers Pmax. Although ballast resistance increases Pmax, the effect reduces as the emitter dot radius increases. This is caused by the non-uniform potential distribution in the base layer. When thermal runaway is considered, the nonuniform base-emitter potential offsets the improvement of the power handling capability by the physical ballast resistance. Conventional HBTs with a large radius (greater than 4 μm) exhibit a small Pmax caused by thermal effect. This threshold power density can be increased drastically by using the thermal shunt technique.

Efficient Design in a DC to DC Converter Unit

NASA Technical Reports Server (NTRS)

Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.

2002-01-01

Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.

Dendritic cell based vaccines: progress in immunotherapy studies for prostate cancer.

PubMed

Ragde, Haakon; Cavanagh, William A; Tjoa, Benjamin A

2004-12-01

No effective treatment is currently available for metastatic prostate cancer. Dendritic cell (DC) based cancer vaccine research has emerged from the laboratories to human clinical trials. We describe progress in the development of DC based prostate cancer vaccine. The literature was reviewed for major contributions to a growing number of studies that demonstrate the potential of DC based immunotherapeutics for prostate cancer. Background topics relating to DC based immunotherapy theory and practice are also addressed. DCs have been recognized as the most efficient antigen presenting cells that have the capacity to initiate naive T cell response in vitro and in vivo. During their differentiation and maturation pathways, dendritic cells can efficiently capture, process and present antigens for T cell activation. These characteristics make DC an attractive choice as the cellular adjuvant for cancer vaccines. Advances in DC generation, loading, and maturation methodologies have made it possible to generate clinical grade vaccines for various human trials. More than 100 DC vaccine trials, including 7 studies of patients with advanced prostate cancer have been reported to date. These vaccines were generally well tolerated with no significant adverse toxicity reported. Clinical responders have been identified in these studies. The new prospects opened by DC based vaccines for prostate cancer are fascinating. When compared to conventional treatments, DC vaccinations have few side effects. Improvements in patient selection, vaccine delivery strategies, immune monitoring and vaccine manufacturing will be crucial in moving DC based prostate cancer vaccines closer to the clinics.

Superfluid helium-4 interferometers: construction and experiments

NASA Astrophysics Data System (ADS)

Joshi, Aditya Ajit

This dissertation has two main goals: to highlight some new results in the field of superfluid 4He interferometry and to provide an in-depth, "hands-on" guide to the physics, design, construction, testing and operation of a continuously operating, fluxlocked 4 He dc-SHeQUID (Superfluid Helium Quantum Interference Device). Many of these topics haven't really been addressed in writing and the hapless new experimenter seeking to develop a SHeQUID is generally forced to reinvent the wheel rather than start at the frontier and push it forward. We would like to prevent that by making this a comprehensive guide to building and operating SHeQUIDs. We have optimized the fabrication of the nanoscale aperture arrays that are the very heart of the SHeQUID and resolved long-standing issues with their durability and long-term usability. A detailed report on this should assist in avoiding the many pitfalls that await those who fabricate and use these aperture arrays. We have constructed a new, modular SHeQUID that is designed to be easily adaptable to a wide array of proposed experiments without the necessity of rebuilding and reassembling key components like the displacement transducer. We have automated its working as a continuously operating, linearized (flux-locked) interferometer by using the so-called "chemical potential battery" in conjunction with a feedback system. We have also constructed a new reorientation system that is several orders of magnitude quieter than its predecessors. Together, these developments have allowed us to measure a changing rotation field in real time, a new development for this kind of device. We have also developed a module that allows control of the reorientation stage by automated data-taking software for investigating long-term drifts (by safely sweeping the stage back and forth). We have also investigated the chemical potential battery in further detail and report some fascinating nonlinear mode locking phenomena that have important consequences for practical applications of these devices. We present a crude model that should help in designing and optimizing future devices by giving us at least an initial predictive tool for the critical heater power needed to initiate battery states. Finally, we analyze some misconceptions about SHeQUIDs regarding what may be considered the logical next step towards improving a double-slit interferometer---the superfluid diffraction grating. We present evidence (experiments, simulations and analytical results) for the somewhat subtle reasons why gratings would be less useful than previously believed and clarifies the proper, limited sense in which such devices do improve SHeQUIDs. We also discuss some possible implications of these issues for the field of (electronic) dc-SQUIDs.

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.

Dendritic Cell-specific Intercellular Adhesion Molecule 3-grabbing Non-integrin (DC-SIGN) Recognizes a Novel Ligand, Mac-2-binding Protein, Characteristically Expressed on Human Colorectal Carcinomas*

PubMed Central

Nonaka, Motohiro; Ma, Bruce Yong; Imaeda, Hirotsugu; Kawabe, Keiko; Kawasaki, Nobuko; Hodohara, Keiko; Kawasaki, Nana; Andoh, Akira; Fujiyama, Yoshihide; Kawasaki, Toshisuke

2011-01-01

Dendritic cell (DC)-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) is a type II transmembrane C-type lectin expressed on DCs such as myeloid DCs and monocyte-derived DCs (MoDCs). Recently, we have reported that DC-SIGN interacts with carcinoembryonic antigen (CEA) expressed on colorectal carcinoma cells. CEA is one of the most widely used tumor markers for gastrointestinal cancers such as colorectal cancer. On the other hand, other groups have reported that the level of Mac-2-binding protein (Mac-2BP) increases in patients with pancreatic, breast, and lung cancers, virus infections such as human immunodeficiency virus and hepatitis C virus, and autoimmune diseases. Here, we first identified Mac-2BP expressed on several colorectal carcinoma cell lines as a novel DC-SIGN ligand through affinity chromatography and mass spectrometry. Interestingly, we found that DC-SIGN selectively recognizes Mac-2BP derived from some colorectal carcinomas but not from the other ones. Furthermore, we found that the α1-3,4-fucose moieties of Le glycans expressed on DC-SIGN-binding Mac-2BP were important for recognition. DC-SIGN-dependent cellular interactions between immature MoDCs and colorectal carcinoma cells significantly inhibited MoDC functional maturation, suggesting that Mac-2BP may provide a tolerogenic microenvironment for colorectal carcinoma cells through DC-SIGN-dependent recognition. Importantly, Mac-2BP was detected as a predominant DC-SIGN ligand expressed on some primary colorectal cancer tissues from certain parts of patients in comparison with CEA from other parts, suggesting that DC-SIGN-binding Mac-2BP bearing tumor-associated Le glycans may become a novel potential colorectal cancer biomarker for some patients instead of CEA. PMID:21515679

Biology, herbivory, and host specificity of Antiblemma leucocyma (Lepidoptera: Noctuidae) on Miconia calvescens DC. (Melastomataceae) in Brazil

Treesearch

F. R. Badenes-Perez; M. T. Johnson

2008-01-01

Miconia calvescens DC. (Melastomataceae) is an invasive tree considered one of the greatest threats to natural ecosystems of Hawaii and other Pacific islands. The potential for using the defoliator Antiblemma leucocyma (Lepidoptera: Noctuidae) as a biological control agent of M. calvescens was evaluated in...

Plasmacytoid dendritic cells: no longer an enigma and now key to transplant tolerance?

PubMed Central

Rogers, NM; Isenberg, JS; Thomson, AW

2014-01-01

Plasmacytoid (p) dendritic cells (DC) are a specialized subset of DC whose primary role was initially defined by the production of type I interferons in response to viral infection. They are now known to also possess a repertoire of functions capable of determining T cell fate and activation. Under homeostatic conditions, non-lymphoid tissue-resident pDC play a critical role in the regulation of mucosal immunity, as well as the development of central and peripheral tolerance. Although these cells display a number of characteristics that differ from conventional DC, particularly altered costimulatory molecule expression and poor allostimulatory capacity when interacting with T cells, this phenotype favors the generation of alloantigen-specific regulatory CD4+ or CD8+ T cells critical to the development of graft tolerance. In this minireview we discuss pDC ontogeny, functional biology and the emerging data that demonstrate the importance of pDC in the induction of tolerance, as well as recent studies that define mechanisms underlying pDC-mediated tolerance to both solid organ and hematopoietic stem cell transplantats. We also highlight their use in clinical settings and the potential of pDC both as targets and cellular therapeutic agents to improve the outcome of organ transplantation. PMID:23617754

A Bidirectional High-Power-Quality Grid Interface With a Novel Bidirectional Noninverted Buck Boost Converter for PHEVs

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

Onar, Omer C

2012-01-01

Plug-in hybrid electric vehicles (PHEVs) will play a vital role in future sustainable transportation systems due to their potential in terms of energy security, decreased environmental impact, improved fuel economy, and better performance. Moreover, new regulations have been established to improve the collective gas mileage, cut greenhouse gas emissions, and reduce dependence on foreign oil. This paper primarily focuses on two major thrust areas of PHEVs. First, it introduces a grid-friendly bidirectional alternating current/direct current ac/dc dc/ac rectifier/inverter for facilitating vehicle-to-grid (V2G) integration of PHEVs. Second, it presents an integrated bidirectional noninverted buck boost converter that interfaces the energy storagemore » device of the PHEV to the dc link in both grid-connected and driving modes. The proposed bidirectional converter has minimal grid-level disruptions in terms of power factor and total harmonic distortion, with less switching noise. The integrated bidirectional dc/dc converter assists the grid interface converter to track the charge/discharge power of the PHEV battery. In addition, while driving, the dc/dc converter provides a regulated dc link voltage to the motor drive and captures the braking energy during regenerative braking.« less

Discovery of novel immunostimulants by dendritic-cell–based functional screening

PubMed Central

Mizumoto, Norikatsu; Gao, Jimin; Matsushima, Hironori; Ogawa, Yasushi; Tanaka, Hiroaki; Takashima, Akira

2005-01-01

Immunostimulants represent an emerging class of drugs for the treatment of infectious disorders and cancer. CpG oligonucleotides and imiquimod, prototypic drugs in this category, are now known to activate dendritic cells (DCs). Here we report the development of a highly sensitive, unbiased functional screen to detect DC-stimulatory signals. Because interleukin-1β (IL-1β) mRNA expression is closely associated with DC activation, we engineered DCs to stably express a fluorescent marker gene under the control of IL-1β promoter. By screening about 3000 compounds with the resulting DC biosensor clone, we identified DC-stimulatory potentials of topoisomerase I inhibitors (camptothecin derivatives) and microtubule depolymerizing drugs (colchicine and podophyllotoxin). In response to treatment with each agent, bone marrow–derived DC preparations exhibited characteristic phenotypic and/or functional changes associated with DC activation. All of these agents also triggered nuclear factor–κB (NFκB) activation in DCs, suggesting a common pharmacologic mechanism of action. Furthermore, locally administered colchicine induced in situ maturation and migration of DCs and augmented both humoral and cellular immune responses. These results support the practical utility of the DC-based biosensor system to discover novel DC-targeted immunostimulants and unveil previously unrecognized (and totally unexpected) pharmacologic activities of several drugs that are commonly used for the treatment of various disorders. PMID:16002424

Hydrophilic Chlorin e6-Poly(amidoamine) Dendrimer Nanoconjugates for Enhanced Photodynamic Therapy.

PubMed

Lee, So-Ri; Kim, Young-Jin

2018-06-18

In photodynamic therapy (PDT), chlorin e6 (Ce6), with its high phototoxic potential and strong absorption of visible light, penetrates deeply into photodamaged tissue. However, despite this fact, the direct application of Ce6 to PDT has been limited by its low water solubility and poor cancer cell localization. To ameliorate this situation, we report herein on the use of a hydrophilic nanoconjugate (DC) comprised of Ce6 and poly(amidoamine) dendrimer, which improves the water solubility and intracellular uptake of Ce6, thereby enhancing PDT efficacy. The synthesis of DC was verified by ¹H nuclear magnetic resonance (NMR) analysis, and the coupling ratio of Ce6 introduced onto DC was 2.64. The prepared DC was spherical, with an average diameter of 61.7 ± 3.5 nm. In addition, the characteristic ultraviolet-visible absorption bands of DC in distilled water were similar to those of free Ce6 in dimethyl sulfoxide (DMSO), indicating that the Ce6 chromophore did not change upon conjugation. Investigation using fluorescence spectroscopy and confocal microscopy revealed a greater intracellular uptake of DC than of Ce6 alone. Moreover, DC exhibited significantly increased phototoxicity to human cervical cancer cells, mostly because of apoptotic cell death. These results imply that DC is a candidate for the clinical treatment of PDT.

High Voltage Design Concepts for Launch Vehicles and Orbital Spacecraft Applications

NASA Technical Reports Server (NTRS)

Hall, David K.; Kirkici, Hulya; Hillard, G. Barry; Schweickart, Daniel; Dunbar, Bill

2000-01-01

With the advent of design concepts such as, electromechanical actuation and "more electric" initiatives, has come the need for electrical power buses and electronic equipment to operate at higher than normal dc voltages to meet power requirements while keeping current levels to manageable levels. This new bus voltage has been typically 270 Volts dc nominal for launch vehicles, and 120 Volt dc for the International Space Station. This paper will discuss the new design applications for high voltage dc power in existing and future launch vehicles and spacecraft and the potential problems associated therewith. These new applications must be operational from lift-off, ascent, on orbit and descent in all of the pressure and temperature conditions for each, i.e. through the "Paschen region" twice. This paper will also attempt to stimulate an interest in the academic and professional communities to support and conduct research needed for design data applicable to high voltage dc usage.

Faraday-Shielded dc Stark-Shift-Free Optical Lattice Clock

NASA Astrophysics Data System (ADS)

Beloy, K.; Zhang, X.; McGrew, W. F.; Hinkley, N.; Yoon, T. H.; Nicolodi, D.; Fasano, R. J.; Schäffer, S. A.; Brown, R. C.; Ludlow, A. D.

2018-05-01

We demonstrate the absence of a dc Stark shift in an ytterbium optical lattice clock. Stray electric fields are suppressed through the introduction of an in-vacuum Faraday shield. Still, the effectiveness of the shielding must be experimentally assessed. Such diagnostics are accomplished by applying high voltage to six electrodes, which are grounded in normal operation to form part of the Faraday shield. Our measurements place a constraint on the dc Stark shift at the 10-20 level, in units of the clock frequency. Moreover, we discuss a potential source of error in strategies to precisely measure or cancel nonzero dc Stark shifts, attributed to field gradients coupled with the finite spatial extent of the lattice-trapped atoms. With this consideration, we find that Faraday shielding, complemented with experimental validation, provides both a practically appealing and effective solution to the problem of dc Stark shifts in optical lattice clocks.

Faraday-Shielded dc Stark-Shift-Free Optical Lattice Clock.

PubMed

Beloy, K; Zhang, X; McGrew, W F; Hinkley, N; Yoon, T H; Nicolodi, D; Fasano, R J; Schäffer, S A; Brown, R C; Ludlow, A D

2018-05-04

We demonstrate the absence of a dc Stark shift in an ytterbium optical lattice clock. Stray electric fields are suppressed through the introduction of an in-vacuum Faraday shield. Still, the effectiveness of the shielding must be experimentally assessed. Such diagnostics are accomplished by applying high voltage to six electrodes, which are grounded in normal operation to form part of the Faraday shield. Our measurements place a constraint on the dc Stark shift at the 10^{-20} level, in units of the clock frequency. Moreover, we discuss a potential source of error in strategies to precisely measure or cancel nonzero dc Stark shifts, attributed to field gradients coupled with the finite spatial extent of the lattice-trapped atoms. With this consideration, we find that Faraday shielding, complemented with experimental validation, provides both a practically appealing and effective solution to the problem of dc Stark shifts in optical lattice clocks.

High torque DC motor fabrication and test program

NASA Technical Reports Server (NTRS)

Makus, P.

1976-01-01

The testing of a standard iron and standard alnico permanent magnet two-phase, brushless dc spin motor for potential application to the space telescope has been concluded. The purpose of this study was to determine spin motor power losses, magnetic drag, efficiency and torque speed characteristics of a high torque dc motor. The motor was designed and built to fit an existing reaction wheel as a test vehicle and to use existing brass-board commutation and torque command electronics. The results of the tests are included in this report.

Defense Department Cyber Efforts: More Detailed Guidance Needed to Ensure Military Services Develop Appropriate Cyberspace Capabilities

DTIC Science & Technology

2011-05-01

communications and on computer networks—its Global Information Grid—which are potentially jeopardized by the millions of denial-of-service attacks, hacking ...Director,a National Security Agency Chief of Staff Joint Operations Center Defense Information Systems Agency Command Center J1 J2 J3 J4 J5 J6 J7 J8...DC Joint Staff • J39, Operations, Pentagon, Washington, DC • J5 , Strategic Plans and Policy, Pentagon, Washington, DC U.S. Strategic Command • J882

Proteomic analysis of human dental cementum and alveolar bone.

PubMed

Salmon, Cristiane R; Tomazela, Daniela M; Ruiz, Karina Gonzales Silvério; Foster, Brian L; Paes Leme, Adriana Franco; Sallum, Enilson Antonio; Somerman, Martha J; Nociti, Francisco H

2013-10-08

Dental cementum (DC) is a bone-like tissue covering the tooth root and responsible for attaching the tooth to the alveolar bone (AB) via the periodontal ligament (PDL). Studies have unsuccessfully tried to identify factors specific to DC versus AB, in an effort to better understand DC development and regeneration. The present study aimed to use matched human DC and AB samples (n=7) to generate their proteomes for comparative analysis. Bone samples were harvested from tooth extraction sites, whereas DC samples were obtained from the apical root portion of extracted third molars. Samples were denatured, followed by protein extraction reduction, alkylation and digestion for analysis by nanoAcquity HPLC system and LTQ-FT Ultra. Data analysis demonstrated that a total of 318 proteins were identified in AB and DC. In addition to shared proteins between these tissues, 105 and 83 proteins exclusive to AB or DC were identified, respectively. This is the first report analyzing the proteomic composition of human DC matrix and identifying putative unique and enriched proteins in comparison to alveolar bone. These findings may provide novel insights into developmental differences between DC and AB, and identify candidate biomarkers that may lead to more efficient and predictable therapies for periodontal regeneration. Periodontal disease is a highly prevalent disease affecting the world population, which involves breakdown of the tooth supporting tissues, the periodontal ligament, alveolar bone, and dental cementum. The lack of knowledge on specific factors that differentiate alveolar bone and dental cementum limits the development of more efficient and predictable reconstructive therapies. In order to better understand cementum development and potentially identify factors to improve therapeutic outcomes, we took the unique approach of using matched patient samples of dental cementum and alveolar bone to generate and compare a proteome list for each tissue. A potential biomarker for dental cementum was identified, superoxide dismutase 3 (SOD3), which is found in cementum and cementum-associated cells in mouse, pig, and human tissues. These findings may provide novel insights into developmental differences between alveolar bone and dental cementum, and represent the basis for improved and more predictable therapies. © 2013.

Middle ear muscle contractions and their relation to pulse and echo evoked potentials in the bat

NASA Technical Reports Server (NTRS)

Henson, O. W., Jr.; Henson, M. M.

1972-01-01

An analysis is made of pulse and echo orientation cries of the Mustache Bat. That bat's cries are characterized by a long, 60 to 30 msec, pure tone component and brief beginning and terminal FM sweeps. In addition to obvious echo overlap and middle ear muscle contractions, the following are examined: (1) characteristics of pulse- and echo-evoked potential under various conditions, (2) evidence of changes in hearing sensitivity during and after pulse emission, and (3) the role of the middle ear muscles in bringing about these changes.

The Retarding Potential Analyzer for Dynamics Explorer-B

NASA Technical Reports Server (NTRS)

Hanson, W. B.; Heelis, R. A.; Power, R. A.; Lippincott, C. R.; Zuccaro, D. R.; Holt, B. J.; Harmon, L. H.; Sanatani, S.

1981-01-01

The Retarding Potential Analyzer for Dynamics Explorer B measures the bulk ion velocity in the direction of the spacecraft motion, the constituent ion concentrations and the ion temperature along the satellite path. These parameters are derived from a least squares fit to the ion number flux versus energy curve obtained by sweeping or stepping the voltage applied to the internal retarding grids of the RPA. In addition, the spectral characteristics of irregularities in the total ion concentration are determined by high time resolution measurements and by use of a comb filter. These data are obtained from a separate wide aperture-sensor.

Anti-Americanism and U.S. Foreign Policy

DTIC Science & Technology

2003-04-07

world. Starting in July 2002, the Pew Research Center interviewed a total of 38,263 people in 44 different nations. The Pew Global Attitudes survey...then, they’ve come to believe that the United States is using that as an excuse for a unilateral foreign policy, and they’re starting to make sweeping...potential alienation that results from the perceived unilateralism could come at a significant cost , particularly when America needs its allies most in

Intracellular studies of hair cells in the mammalian cochlea.

PubMed Central

Russell, I J; Sellick, P M

1978-01-01

1. Intracellular recordings were made from inner hair cells in the first turn of the guinea-pig cochlea, the recording sites being confirmed by the injection of Procion yellow dye and subsequent histology. 2. The receptor potential, in response to a pure tone burst, consisted of an AC response which followed the wave form of the stimulus and was analogous to the extracellularly recorded cochlear microphonic and a depolarizating DC response which followed the envelope of the tone burst and was analogous to the extracellularly recorded summating potential. 3. The DC response was broadly tuned at high sound pressure having a maximal amplitude of 27 mV at a sound pressure level of ca. 100 db; however the bandwidth of the response was reduced at lower sound pressure level. Isoamplitude curves for the DC response were indistinguishable from the threshold curves for auditory nerve fibres. 4. The AC response was tuned in a similar fashion to the DC response except that it was attenuated at 6-9 db/octave with respect to the DC response. It is suggested that this difference was due to the effect of membrane capacitance and resistance on the AC response. In contrast the extracellularly recorded AC component was not subject to this attenuation. 5. The total resistance and capacitance in three cells were found to be 46-61 Momega and 7.8-15.8 muF respectively. 6. Intracellular resistance changes were measured during sound stimulation, the resistance change being proportional to the DC receptor potential, indicating constant current flow through the hair cell. The current varied between 0.37 and 0.81 nA between cells. The time constant for seven cells was found to lie between 0.31 and 0.76 msec. 7. A map of the basilar membrane showing position of hair cells against characteristic frequency corresponded to the cut-off frequencies of the basilar membrane mechanical measurements and the innervation sites of spiral ganglion cells. PMID:731538

Spin-Label CW Microwave Power Saturation and Rapid Passage with Triangular Non-Adiabatic Rapid Sweep (NARS) and Adiabatic Rapid Passage (ARP) EPR Spectroscopy

PubMed Central

Kittell, Aaron W.; Hyde, James S.

2015-01-01

Non-adiabatic rapid passage (NARS) electron paramagnetic resonance (EPR) spectroscopy was introduced by Kittell, A.W., Camenisch, T.G., Ratke, J.J. Sidabras, J.W., Hyde, J.S., 2011 as a general purpose technique to collect the pure absorption response. The technique has been used to improve sensitivity relative to sinusoidal magnetic field modulation, increase the range of inter-spin distances that can be measured under near physiological conditions, and enhance spectral resolution in copper (II) spectra. In the present work, the method is extended to CW microwave power saturation of spin-labeled T4 Lysozyme (T4L). As in the cited papers, rapid triangular sweep of the polarizing magnetic field was superimposed on slow sweep across the spectrum. Adiabatic rapid passage (ARP) effects were encountered in samples undergoing very slow rotational diffusion as the triangular magnetic field sweep rate was increased. The paper reports results of variation of experimental parameters at the interface of adiabatic and non-adiabatic rapid sweep conditions. Comparison of the forward (up) and reverse (down) triangular sweeps is shown to be a good indicator of the presence of rapid passage effects. Spectral turning points can be distinguished from spectral regions between turning points in two ways: differential microwave power saturation and differential passage effects. Oxygen accessibility data are shown under NARS conditions that appear similar to conventional field modulation data. However, the sensitivity is much higher, permitting, in principle, experiments at substantially lower protein concentrations. Spectral displays were obtained that appear sensitive to rotational diffusion in the range of rotational correlation times of 10−3 to 10−7 s in a manner that is analogous to saturation transfer spectroscopy. PMID:25917132

On-line focusing of flavin derivatives using Dynamic pH junction-sweeping capillary electrophoresis with laser-induced fluorescence detection.

PubMed

Britz-McKibbin, Philip; Otsuka, Koji; Terabe, Shigeru

2002-08-01

Simple yet effective methods to enhance concentration sensitivity is needed for capillary electrophoresis (CE) to become a practical method to analyze trace levels of analytes in real samples. In this report, the development of a novel on-line preconcentration technique combining dynamic pH junction and sweeping modes of focusing is applied to the sensitive and selective analysis of three flavin derivatives: riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Picomolar (pM) detectability of flavins by CE with laser-induced fluorescence (LIF) detection is demonstrated through effective focusing of large sample volumes (up to 22% capillary length) using a dual pH junction-sweeping focusing mode. This results in greater than a 1,200-fold improvement in sensitivity relative to conventional injection methods, giving a limit of detection (S/N = 3) of approximately 4.0 pM for FAD and FMN. Flavin focusing is examined in terms of analyte mobility dependence on buffer pH, borate complexation and SDS interaction. Dynamic pH junction-sweeping extends on-line focusing to both neutral (hydrophobic) and weakly acidic (hydrophilic) species and is considered useful in cases when either conventional sweeping or dynamic pH junction techniques used alone are less effective for certain classes of analytes. Enhanced focusing performance by this hyphenated method was demonstrated by greater than a 4-fold reduction in flavin bandwidth, as compared to either sweeping or dynamic pH junction, reflected by analyte detector bandwidths <0.20 cm. Novel on-line focusing strategies are required to improve sensitivity in CE, which may be applied toward more effective biochemical analysis methods for diverse types of analytes.

R2d2 Drives Selfish Sweeps in the House Mouse

PubMed Central

Didion, John P.; Morgan, Andrew P.; Yadgary, Liran; Bell, Timothy A.; McMullan, Rachel C.; Ortiz de Solorzano, Lydia; Britton-Davidian, Janice; Bult, Carol J.; Campbell, Karl J.; Castiglia, Riccardo; Ching, Yung-Hao; Chunco, Amanda J.; Crowley, James J.; Chesler, Elissa J.; Förster, Daniel W.; French, John E.; Gabriel, Sofia I.; Gatti, Daniel M.; Garland, Theodore; Giagia-Athanasopoulou, Eva B.; Giménez, Mabel D.; Grize, Sofia A.; Gündüz, İslam; Holmes, Andrew; Hauffe, Heidi C.; Herman, Jeremy S.; Holt, James M.; Hua, Kunjie; Jolley, Wesley J.; Lindholm, Anna K.; López-Fuster, María J.; Mitsainas, George; da Luz Mathias, Maria; McMillan, Leonard; Ramalhinho, Maria da Graça Morgado; Rehermann, Barbara; Rosshart, Stephan P.; Searle, Jeremy B.; Shiao, Meng-Shin; Solano, Emanuela; Svenson, Karen L.; Thomas-Laemont, Patricia; Threadgill, David W.; Ventura, Jacint; Weinstock, George M.; Pomp, Daniel; Churchill, Gary A.; Pardo-Manuel de Villena, Fernando

2016-01-01

A selective sweep is the result of strong positive selection driving newly occurring or standing genetic variants to fixation, and can dramatically alter the pattern and distribution of allelic diversity in a population. Population-level sequencing data have enabled discoveries of selective sweeps associated with genes involved in recent adaptations in many species. In contrast, much debate but little evidence addresses whether “selfish” genes are capable of fixation—thereby leaving signatures identical to classical selective sweeps—despite being neutral or deleterious to organismal fitness. We previously described R2d2, a large copy-number variant that causes nonrandom segregation of mouse Chromosome 2 in females due to meiotic drive. Here we show population-genetic data consistent with a selfish sweep driven by alleles of R2d2 with high copy number (R2d2HC) in natural populations. We replicate this finding in multiple closed breeding populations from six outbred backgrounds segregating for R2d2 alleles. We find that R2d2HC rapidly increases in frequency, and in most cases becomes fixed in significantly fewer generations than can be explained by genetic drift. R2d2HC is also associated with significantly reduced litter sizes in heterozygous mothers, making it a true selfish allele. Our data provide direct evidence of populations actively undergoing selfish sweeps, and demonstrate that meiotic drive can rapidly alter the genomic landscape in favor of mutations with neutral or even negative effects on overall Darwinian fitness. Further study will reveal the incidence of selfish sweeps, and will elucidate the relative contributions of selfish genes, adaptation and genetic drift to evolution. PMID:26882987

Refining the Use of Linkage Disequilibrium as a Robust Signature of Selective Sweeps

PubMed Central

Jacobs, Guy S.; Sluckin, Timothy J.; Kivisild, Toomas

2016-01-01

During a selective sweep, characteristic patterns of linkage disequilibrium can arise in the genomic region surrounding a selected locus. These have been used to infer past selective sweeps. However, the recombination rate is known to vary substantially along the genome for many species. We here investigate the effectiveness of current (Kelly’s ZnS and ωmax) and novel statistics at inferring hard selective sweeps based on linkage disequilibrium distortions under different conditions, including a human-realistic demographic model and recombination rate variation. When the recombination rate is constant, Kelly’s ZnS offers high power, but is outperformed by a novel statistic that we test, which we call Zα. We also find this statistic to be effective at detecting sweeps from standing variation. When recombination rate fluctuations are included, there is a considerable reduction in power for all linkage disequilibrium-based statistics. However, this can largely be reversed by appropriately controlling for expected linkage disequilibrium using a genetic map. To further test these different methods, we perform selection scans on well-characterized HapMap data, finding that all three statistics—ωmax, Kelly’s ZnS, and Zα—are able to replicate signals at regions previously identified as selection candidates based on population differentiation or the site frequency spectrum. While ωmax replicates most candidates when recombination map data are not available, the ZnS and Zα statistics are more successful when recombination rate variation is controlled for. Given both this and their higher power in simulations of selective sweeps, these statistics are preferred when information on local recombination rate variation is available. PMID:27516617

Refining the Use of Linkage Disequilibrium as a Robust Signature of Selective Sweeps.

PubMed

Jacobs, Guy S; Sluckin, Tim J; Kivisild, Toomas

2016-08-01

During a selective sweep, characteristic patterns of linkage disequilibrium can arise in the genomic region surrounding a selected locus. These have been used to infer past selective sweeps. However, the recombination rate is known to vary substantially along the genome for many species. We here investigate the effectiveness of current (Kelly's [Formula: see text] and [Formula: see text]) and novel statistics at inferring hard selective sweeps based on linkage disequilibrium distortions under different conditions, including a human-realistic demographic model and recombination rate variation. When the recombination rate is constant, Kelly's [Formula: see text] offers high power, but is outperformed by a novel statistic that we test, which we call [Formula: see text] We also find this statistic to be effective at detecting sweeps from standing variation. When recombination rate fluctuations are included, there is a considerable reduction in power for all linkage disequilibrium-based statistics. However, this can largely be reversed by appropriately controlling for expected linkage disequilibrium using a genetic map. To further test these different methods, we perform selection scans on well-characterized HapMap data, finding that all three statistics-[Formula: see text] Kelly's [Formula: see text] and [Formula: see text]-are able to replicate signals at regions previously identified as selection candidates based on population differentiation or the site frequency spectrum. While [Formula: see text] replicates most candidates when recombination map data are not available, the [Formula: see text] and [Formula: see text] statistics are more successful when recombination rate variation is controlled for. Given both this and their higher power in simulations of selective sweeps, these statistics are preferred when information on local recombination rate variation is available. Copyright © 2016 by the Genetics Society of America.

Inner workings of aerodynamic sweep

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

Wadia, A.R.; Szucs, P.N.; Crall, D.W.

1998-10-01

The recent trend in using aerodynamic sweep to improve the performance of transonic blading has been one of the more significant technological evolutions for compression components in turbomachinery. This paper reports on the experimental and analytical assessment of the pay-off derived from both aft and forward sweep technology with respect to aerodynamic performance and stability. The single-stage experimental investigation includes two aft-swept rotors with varying degree and type of aerodynamic sweep and one swept forward rotor. On a back-to-back test basis, the results are compared with an unswept rotor with excellent performance and adequate stall margin. Although designed to satisfymore » identical design speed requirements as the unswept rotor, the experimental results reveal significant variations in efficiency and stall margin with the swept rotors. At design speed, all the swept rotors demonstrated a peak stage efficiency level that was equal to that of the unswept rotor. However, the forward-swept rotor achieved the highest rotor-alone peak efficiency. At the same time, the forward-swept rotor demonstrated a significant improvement in stall margin relative to the already satisfactory level achieved by the unswept rotor. Increasing the level of aft sweep adversely affected the stall margin. A three-dimensional viscous flow analysis was used to assist in the interpretation of the data. The reduced shock/boundary layer interaction, resulting from reduced axial flow diffusion and less accumulation of centrifuged blade surface boundary layer at the tip, was identified as the prime contributor to the enhanced performance with forward sweep. The impact of tip clearance on the performance and stability for one of the aft-swept rotors was also assessed.« less

Secular Resonance Sweeping of the Main Asteroid Belt During Planet Migration

NASA Astrophysics Data System (ADS)

Minton, David A.; Malhotra, Renu

2011-05-01

We calculate the eccentricity excitation of asteroids produced by the sweeping ν6 secular resonance during the epoch of planetesimal-driven giant planet migration in the early history of the solar system. We derive analytical expressions for the magnitude of the eccentricity change and its dependence on the sweep rate and on planetary parameters; the ν6 sweeping leads to either an increase or a decrease of eccentricity depending on an asteroid's initial orbit. Based on the slowest rate of ν6 sweeping that allows a remnant asteroid belt to survive, we derive a lower limit on Saturn's migration speed of ~0.15 AU Myr-1 during the era that the ν6 resonance swept through the inner asteroid belt (semimajor axis range 2.1-2.8 AU). This rate limit is for Saturn's current eccentricity and scales with the square of its eccentricity; the limit on Saturn's migration rate could be lower if its eccentricity were lower during its migration. Applied to an ensemble of fictitious asteroids, our calculations show that a prior single-peaked distribution of asteroid eccentricities would be transformed into a double-peaked distribution due to the sweeping of the ν6 resonance. Examination of the orbital data of main belt asteroids reveals that the proper eccentricities of the known bright (H <= 10.8) asteroids may be consistent with a double-peaked distribution. If so, our theoretical analysis then yields two possible solutions for the migration rate of Saturn and for the dynamical states of the pre-migration asteroid belt: a dynamically cold state (single-peaked eccentricity distribution with mean of ~0.05) linked with Saturn's migration speed ~4 AU Myr-1 or a dynamically hot state (single-peaked eccentricity distribution with mean of ~0.3) linked with Saturn's migration speed ~0.8 AU Myr-1.

Detection of P300 waves in single trials by the wavelet transform (WT).

PubMed

Demiralp, T; Ademoglu, A; Schürmann, M; Başar-Eroglu, C; Başar, E

1999-01-01

The P300 response is conventionally obtained by averaging the responses to the task-relevant (target) stimuli of the oddball paradigm. However, it is well known that cognitive ERP components show a high variability due to changes of cognitive state during an experimental session. With simple tasks such changes may not be demonstrable by the conventional method of averaging the sweeps chosen according to task-relevance. Therefore, the present work employed a response-based classification procedure to choose the trials containing the P300 component from the whole set of sweeps of an auditory oddball paradigm. For this purpose, the most significant response property reflecting the P300 wave was identified by using the wavelet transform (WT). The application of a 5 octave quadratic B-spline-WT on single sweeps yielded discrete coefficients in each octave with an appropriate time resolution for each frequency range. The main feature indicating a P300 response was the positivity of the 4th delta (0.5-4 Hz) coefficient (310-430 ms) after stimulus onset. The average of selected single sweeps from the whole set of data according to this criterion yielded more enhanced P300 waves compared with the average of the target responses, and the average of the remaining sweeps showed a significantly smaller positivity in the P300 latency range compared with the average of the non-target responses. The combination of sweeps classified according to the task-based and response-based criteria differed significantly. This suggests an influence of changes in cognitive state on the presence of the P300 wave which cannot be assessed by task performance alone. Copyright 1999 Academic Press.

Effects of sound intensity on temporal properties of inhibition in the pallid bat auditory cortex.

PubMed

Razak, Khaleel A

2013-01-01

Auditory neurons in bats that use frequency modulated (FM) sweeps for echolocation are selective for the behaviorally-relevant rates and direction of frequency change. Such selectivity arises through spectrotemporal interactions between excitatory and inhibitory components of the receptive field. In the pallid bat auditory system, the relationship between FM sweep direction/rate selectivity and spectral and temporal properties of sideband inhibition have been characterized. Of note is the temporal asymmetry in sideband inhibition, with low-frequency inhibition (LFI) exhibiting faster arrival times compared to high-frequency inhibition (HFI). Using the two-tone inhibition over time (TTI) stimulus paradigm, this study investigated the interactions between two sound parameters in shaping sideband inhibition: intensity and time. Specifically, the impact of changing relative intensities of the excitatory and inhibitory tones on arrival time of inhibition was studied. Using this stimulation paradigm, single unit data from the auditory cortex of pentobarbital-anesthetized cortex show that the threshold for LFI is on average ~8 dB lower than HFI. For equal intensity tones near threshold, LFI is stronger than HFI. When the inhibitory tone intensity is increased further from threshold, the strength asymmetry decreased. The temporal asymmetry in LFI vs. HFI arrival time is strongest when the excitatory and inhibitory tones are of equal intensities or if excitatory tone is louder. As inhibitory tone intensity is increased, temporal asymmetry decreased suggesting that the relative magnitude of excitatory and inhibitory inputs shape arrival time of inhibition and FM sweep rate and direction selectivity. Given that most FM bats use downward sweeps as echolocation calls, a similar asymmetry in threshold and strength of LFI vs. HFI may be a general adaptation to enhance direction selectivity while maintaining sweep-rate selective responses to downward sweeps.

Genome-wide selective sweeps and gene-specific sweeps in natural bacterial populations

DOE PAGES

Bendall, Matthew L.; Stevens, Sarah L.R.; Chan, Leong-Keat; ...

2016-01-08

Multiple models describe the formation and evolution of distinct microbial phylogenetic groups. These evolutionary models make different predictions regarding how adaptive alleles spread through populations and how genetic diversity is maintained. Processes predicted by competing evolutionary models, for example, genome-wide selective sweeps vs gene-specific sweeps, could be captured in natural populations using time-series metagenomics if the approach were applied over a sufficiently long time frame. Direct observations of either process would help resolve how distinct microbial groups evolve. Using a 9-year metagenomic study of a freshwater lake (2005–2013), we explore changes in single-nucleotide polymorphism (SNP) frequencies and patterns of genemore » gain and loss in 30 bacterial populations. SNP analyses revealed substantial genetic heterogeneity within these populations, although the degree of heterogeneity varied by >1000-fold among populations. SNP allele frequencies also changed dramatically over time within some populations. Interestingly, nearly all SNP variants were slowly purged over several years from one population of green sulfur bacteria, while at the same time multiple genes either swept through or were lost from this population. Furthermore, these patterns were consistent with a genome-wide selective sweep in progress, a process predicted by the ‘ecotype model’ of speciation but not previously observed in nature. In contrast, other populations contained large, SNP-free genomic regions that appear to have swept independently through the populations prior to the study without purging diversity elsewhere in the genome. Finally, evidence for both genome-wide and gene-specific sweeps suggests that different models of bacterial speciation may apply to different populations coexisting in the same environment.« less

Ion Trapping, Storage, and Ejection in Structures for Lossless Ion Manipulations

DOE PAGES

Zhang, Xinyu; Garimella, Sandilya V. B.; Prost, Spencer A.; ...

2015-06-14

Here, a structure for lossless ion manipulation (SLIM) module was constructed with electrode arrays patterned on a pair of parallel printed circuit boards (PCB) separated by 5 mm and utilized to investigate capabilities for ion trapping at 4 Torr. Positive ions were confined by application of RF having alternating phases on a series of inner rung electrodes and by positive DC potentials on surrounding guard electrodes on each PCB. An axial DC field was also introduced by stepwise varying the DC potential of the inner rung electrodes so as to control the ion transport and accumulation inside the ion trap.more » We show that ions could be trapped and accumulated with 100% efficiency, stored for at least 5 hours with no losses, and could be rapidly ejected from the SLIM trap.« less

A dendritic cell-stromal axis maintains immune responses in lymph nodes

PubMed Central

Kumar, Varsha; Dasoveanu, Dragos C.; Chyou, Susan; Tzeng, Te-Chen; Rozo, Cristina; Liang, Yong; Stohl, William; Fu, Yang-Xin; Ruddle, Nancy; Lu, Theresa T.

2015-01-01

Summary Within secondary lymphoid tissues, stromal reticular cells support lymphocyte function, and targeting reticular cells is a potential strategy for controlling pathogenic lymphocytes in disease. However, the mechanisms that regulate reticular cell function are not well understood. Here we found that during an immune response in lymph nodes, dendritic cells (DCs) maintain reticular cell survival in multiple compartments. DC-derived lymphotoxin beta receptor (LTβR) ligands were critical mediators, and LTβR signaling on reticular cells mediated cell survival by modulating podoplanin (PDPN). PDPN modulated integrin-mediated cell adhesion, which maintained cell survival. This DC-stromal axis maintained lymphocyte survival and the ongoing immune response. Our findings provide insight into the functions of DCs, LTβR, and PDPN and delineate a DC-stromal axis that can potentially be targeted in autoimmune or lymphoproliferative diseases. PMID:25902483

Harnessing dendritic cells in inflammatory skin diseases.

PubMed

Chu, Chung-Ching; Di Meglio, Paola; Nestle, Frank O

2011-02-01

The skin immune system harbors a complex network of dendritic cells (DCs). Recent studies highlight a diverse functional specialization of skin DC subsets. In addition to generating cellular and humoral immunity against pathogens, skin DCs are involved in tolerogenic mechanisms to ensure the maintenance of immune homeostasis, as well as in pathogenesis of chronic inflammation in the skin when excessive immune responses are initiated and unrestrained. Harnessing DCs by directly targeting DC-derived molecules or selectively modulate DC subsets is a convincing strategy to tackle inflammatory skin diseases. In this review we discuss recent advances underlining the functional specialization of skin DCs and discuss the potential implication for future DC-based therapeutic strategies. Copyright © 2011 Elsevier Ltd. All rights reserved.

Differential cytotoxicity of long-chain bases for human oral gingival epithelial keratinocytes, oral fibroblasts, and dendritic cells.

PubMed

Mehalick, Leslie A; Poulsen, Christopher; Fischer, Carol L; Lanzel, Emily A; Bates, Amber M; Walters, Katherine S; Cavanaugh, Joseph E; Guthmiller, Janet M; Johnson, Georgia K; Wertz, Philip W; Brogden, Kim A

2015-12-01

Long-chain bases, found in the oral cavity, have potent antimicrobial activity against oral pathogens. In an article associated with this dataset, Poulson and colleagues determined the cytotoxicities of long-chain bases (sphingosine, dihydrosphingosine, and phytosphingosine) for human oral gingival epithelial (GE) keratinocytes, oral gingival fibroblasts (GF), dendritic cells (DC), and squamous cell carcinoma (SCC) cell lines [1]. Poulson and colleagues found that GE keratinocytes were more resistant to long-chain bases as compared to GF, DC, and SCC cell lines [1]. In this study, we assess the susceptibility of DC to lower concentrations of long chain bases. 0.2-10.0 µM long-chain bases and GML were not cytotoxic to DC; 40.0-80.0 µM long-chain bases, but not GML, were cytotoxic for DC; and 80.0 µM long-chain bases were cytotoxic to DC and induced cellular damage and death in less than 20 mins. Overall, the LD50 of long-chain bases for GE keratinocytes, GF, and DC were considerably higher than their minimal inhibitory concentrations for oral pathogens, a finding important to pursuing their future potential in treating periodontal and oral infections.

The Series Connected Buck Boost Regulator Concept for High Efficiency Light Weight DC Voltage Regulation

NASA Technical Reports Server (NTRS)

Birchenough, Arthur G.

2003-01-01

Improvements in the efficiency and size of DC-DC converters have resulted from advances in components, primarily semiconductors, and improved topologies. One topology, which has shown very high potential in limited applications, is the Series Connected Boost Unit (SCBU), wherein a small DC-DC converter output is connected in series with the input bus to provide an output voltage equal to or greater than the input voltage. Since the DC-DC converter switches only a fraction of the power throughput, the overall system efficiency is very high. But this technique is limited to applications where the output is always greater than the input. The Series Connected Buck Boost Regulator (SCBBR) concept extends partial power processing technique used in the SCBU to operation when the desired output voltage is higher or lower than the input voltage, and the implementation described can even operate as a conventional buck converter to operate at very low output to input voltage ratios. This paper describes the operation and performance of an SCBBR configured as a bus voltage regulator providing 50 percent voltage regulation range, bus switching, and overload limiting, operating above 98 percent efficiency. The technique does not provide input-output isolation.

[Survey of sharpshooters (Hemiptera: Cicadellidae) associated with Xylella fastidiosa transmission in citrus groves of the North Coast of Bahia State].

PubMed

De Miranda, Marcelo P; Lopes, João R S; Do Nascimento, Antonio S; Dos Santos, José L; Cavichioli, Rodney R

2009-01-01

The causal agent of citrus variegated clorosis, Xylella fastidiosa, is transmitted by leafhoppers of the subfamily Cicadellinae, whose species vary regionally. The goal of this study was to identify potential vectors of this pathogen in citrus groves of Bahia North Coast, Brazil. The survey was done from March/2002 to February/2003 in three seven- to nine-year-old sweet orange (Citrus sinensis, Pêra variety) groves located in Rio Real, BA. Fifteen yellow sticky cards (8.5x11.5 cm) were installed 40 m apart in each grove, hanged at 1.5 m high on the upper north side of citrus canopies, and replaced fortnightly. A sweep net was periodically used to sample leafhoppers on herbaceous weeds inside the groves, by selecting five points at random and performing 30 sweeps in each point. A total of 1,360 specimens of 49 Auchenorrhyncha species were collected in this study, mostly in the family Cicadellidae (90.2%). The subfamily Cicadellinae, which includes the sharpshooter vectors of X. fastidiosa, showed the largest number of species (14) and specimens (84.8%). Acrogonia flagellata Young, A. citrina Marucci & Cavichioli, Homalodisca spottii Takiya, Cavichioli & McKamey and an unidentified Cicadellini (species 1) were the dominant species trapped on citrus canopies, while Hortensia similis (Walker) and Erythrogonia dubia (Medler) were dominant in the weedy vegetation. Among the Cicadellinae species already known as vectors of X. fastidiosa in citrus, only A. citrina, Bucephalogonia xanthophis (Berg) e Ferrariana trivittata (Signoret) were found. The two latter species were accidentally trapped by sweep net in the weedy vegetation.

Elimination of Gaseous Microemboli from Cardiopulmonary Bypass using Hypobaric Oxygenation

PubMed Central

Gipson, Keith E.; Rosinski, David J.; Schonberger, Robert B.; Kubera, Cathryn; Mathew, Eapen S.; Nichols, Frank; Dyckman, William; Courtin, Francois; Sherburne, Bradford; Bordey, Angelique F; Gross, Jeffrey B.

2014-01-01

Background Numerous gaseous microemboli (GME) are delivered into the arterial circulation during cardiopulmonary bypass (CPB). These emboli damage end organs through multiple mechanisms that are thought to contribute to neurocognitive deficits following cardiac surgery. Here, we use hypobaric oxygenation to reduce dissolved gases in blood and greatly reduce GME delivery during CPB. Methods Variable subatmospheric pressures were applied to 100% oxygen sweep gas in standard hollow fiber microporous membrane oxygenators to oxygenate and denitrogenate blood. GME were quantified using ultrasound while air embolism from the surgical field was simulated experimentally. We assessed end organ tissues in swine postoperatively using light microscopy. Results Variable sweep gas pressures allowed reliable oxygenation independent of CO2 removal while denitrogenating arterial blood. Hypobaric oxygenation produced dose-dependent reductions of Doppler signals produced by bolus and continuous GME loads in vitro. Swine were maintained using hypobaric oxygenation for four hours on CPB with no apparent adverse events. Compared with current practice standards of O2/air sweep gas, hypobaric oxygenation reduced GME volumes exiting the oxygenator (by 80%), exiting the arterial filter (95%), and arriving at the aortic cannula (∼100%), indicating progressive reabsorption of emboli throughout the CPB circuit in vivo. Analysis of brain tissue suggested decreased microvascular injury under hypobaric conditions. Conclusions Hypobaric oxygenation is an effective, low-cost, common sense approach that capitalizes on the simple physical makeup of GME to achieve their near-total elimination during CPB. This technique holds great potential for limiting end-organ damage and improving outcomes in a variety of patients undergoing extracorporeal circulation. PMID:24206970

Pollutant loading to stormwater runoff from highways : impact of a highway sweeping program.

DOT National Transportation Integrated Search

2010-01-01

This report describes the methods used to collect stormwater runoff and evaluate a street sweeping program on U.S. : Highway 151 in Madison, Wisconsin. The study was a cooperative effort among the Wisconsin Department of : Transportation (WisDOT), U....

Magnetic roller gas gate employing transonic sweep gas flow to isolate regions of differing gaseous composition or pressure

DOEpatents

Doehler, Joachim

1994-12-20

Disclosed herein is an improved gas gate for interconnecting regions of differing gaseous composition and/or pressure. The gas gate includes a narrow, elongated passageway through which substrate material is adapted to move between said regions and inlet means for introducing a flow of non-contaminating sweep gas into a central portion of said passageway. The gas gate is characterized in that the height of the passageway and the flow rate of the sweep gas therethrough provides for transonic flow of the sweep gas between the inlet means and at least one of the two interconnected regions, thereby effectively isolating one region, characterized by one composition and pressure, from another region, having a differing composition and/or pressure, by decreasing the mean-free-path length between collisions of diffusing species within the transonic flow region. The gas gate preferably includes a manifold at the juncture point where the gas inlet means and the passageway interconnect.

The effect of canard leading edge sweep and dihedral angle on the longitudinal and lateral aerodynamic characteristic of a close-coupled canard-wing configuration

NASA Technical Reports Server (NTRS)

Gloss, B. B.

1974-01-01

A generalized wind-tunnel model, with canard and wing planforms typical of highly maneuverable aircraft, was tested in the Langley high-speed 7- by 10-foot tunnel at a Mach number of 0.30. The test was conducted in order to determine the effects of canard sweep and canard dihedral on canard-wing interference at high angles of attack. In general, the effect of canard sweep on lift is small up to an angle of attack of 16 deg. However, for angles of attack greater than 16 deg, an increase in the canard sweep results in an increase in lift developed by the canard when the canard is above or in the wing chord plane. This increased lift results in a lift increase for the total configuration for the canard above the wing chord plane. For the canard in the wing chord plane, the increased canard lift is partially lost by increased interference on the wing.

Fast sweeping method for the factored eikonal equation

NASA Astrophysics Data System (ADS)

Fomel, Sergey; Luo, Songting; Zhao, Hongkai

2009-09-01

We develop a fast sweeping method for the factored eikonal equation. By decomposing the solution of a general eikonal equation as the product of two factors: the first factor is the solution to a simple eikonal equation (such as distance) or a previously computed solution to an approximate eikonal equation. The second factor is a necessary modification/correction. Appropriate discretization and a fast sweeping strategy are designed for the equation of the correction part. The key idea is to enforce the causality of the original eikonal equation during the Gauss-Seidel iterations. Using extensive numerical examples we demonstrate that (1) the convergence behavior of the fast sweeping method for the factored eikonal equation is the same as for the original eikonal equation, i.e., the number of iterations for the Gauss-Seidel iterations is independent of the mesh size, (2) the numerical solution from the factored eikonal equation is more accurate than the numerical solution directly computed from the original eikonal equation, especially for point sources.

Free and forced Barkhausen noises in magnetic thin film based cross-junctions

NASA Astrophysics Data System (ADS)

Elzwawy, Amir; Talantsev, Artem; Kim, CheolGi

2018-07-01

Barkhausen noise, driven by thermal fluctuations in stationary magnetic field, and Barkhausen jumps, driven by sweeping magnetic field, are demonstrated to be effects of different orders of magnitude. The critical magnetic field for domain walls depinning, followed by avalanched and irreversible magnetization jumps, is determined. Magnetoresistive response of NiFe/M/NiFe (M = Au, Ta, Ag) trilayers to stationary and sweeping magnetic field is studied by means of anisotropic magnetoresistance (AMR) and planar Hall effect (PHE) measurements. Thermal fluctuations result in local and reversible changes of magnetization of the layers in thin film magnetic junctions, while the sweeping magnetic field results in reversible and irreversible avalanched domain motion, dependently on the ratio between the values of sweeping magnetic field and domain wall depinning field. The correlation between AMR and PHE responses to Barkhausen jumps is studied. The value of this correlation is found to be dependent on the α angle between the directions of magnetic field and current path.

Analysis of Pheochromocytoma (PC12) Membrane Potential under the Exposure to Millimeter-wave Radiation

NASA Astrophysics Data System (ADS)

Mizuno, M.; Hirata, A.; Kawase, K.; Otani, C.; Nagatsuma, T.

2004-08-01

Non-thermal effects of millimeter wave (MMW) on Pheochromocytoma (PC12) were studied by potential measurement with a voltage sensitive dye (DiBAC4(3)). Cells were irradiated at fixed frequencies of 30, 40, 60, 76GHz as well as sweeping frequency between 10 and 100 GHz by an MMW generator based on a uni-traveling-carrier photodiode (UTC-PD), the most widely tunable MMW source. However there were no significant changes in membrane potential between MMW-irradiated and control cells. The results suggest that MMW irradiation in the range from 10 to 100GHz appears to be safe for ordinary PC12 cells under non-thermal conditions.

A visualization instrument to investigate the mechanical-electro properties of high temperature superconducting tapes under multi-fields

NASA Astrophysics Data System (ADS)

Liu, Wei; Zhang, Xingyi; Liu, Cong; Zhang, Wentao; Zhou, Jun; Zhou, YouHe

2016-07-01

We construct a visible instrument to study the mechanical-electro behaviors of high temperature superconducting tape as a function of magnetic field, strain, and temperature. This apparatus is directly cooled by a commercial Gifford-McMahon cryocooler. The minimum temperature of sample can be 8.75 K. A proportion integration differentiation temperature control is used, which is capable of producing continuous variation of specimen temperature from 8.75 K to 300 K with an optional temperature sweep rate. We use an external loading device to stretch the superconducting tape quasi-statically with the maximum tension strain of 20%. A superconducting magnet manufactured by the NbTi strand is applied to provide magnetic field up to 5 T with a homogeneous range of 110 mm. The maximum fluctuation of the magnetic field is less than 1%. We design a kind of superconducting lead composed of YBa2Cu3O7-x coated conductor and beryllium copper alloy (BeCu) to transfer DC to the superconducting sample with the maximum value of 600 A. Most notably, this apparatus allows in situ observation of the electromagnetic property of superconducting tape using the classical magnetic-optical imaging.

A visualization instrument to investigate the mechanical-electro properties of high temperature superconducting tapes under multi-fields.

PubMed

Liu, Wei; Zhang, Xingyi; Liu, Cong; Zhang, Wentao; Zhou, Jun; Zhou, YouHe

2016-07-01

We construct a visible instrument to study the mechanical-electro behaviors of high temperature superconducting tape as a function of magnetic field, strain, and temperature. This apparatus is directly cooled by a commercial Gifford-McMahon cryocooler. The minimum temperature of sample can be 8.75 K. A proportion integration differentiation temperature control is used, which is capable of producing continuous variation of specimen temperature from 8.75 K to 300 K with an optional temperature sweep rate. We use an external loading device to stretch the superconducting tape quasi-statically with the maximum tension strain of 20%. A superconducting magnet manufactured by the NbTi strand is applied to provide magnetic field up to 5 T with a homogeneous range of 110 mm. The maximum fluctuation of the magnetic field is less than 1%. We design a kind of superconducting lead composed of YBa2Cu3O7-x coated conductor and beryllium copper alloy (BeCu) to transfer DC to the superconducting sample with the maximum value of 600 A. Most notably, this apparatus allows in situ observation of the electromagnetic property of superconducting tape using the classical magnetic-optical imaging.

Self-Rectifying Effect in Resistive Switching Memory Using Amorphous InGaZnO

NASA Astrophysics Data System (ADS)

Lee, Jin-Woo; Kwon, Hyeon-Min; Kim, Myeong-Ho; Lee, Seung-Ryul; Kim, Young-Bae; Choi, Duck-Kyun

2014-05-01

Resistance random access memory (ReRAM) has received attention as next-generation memory because of its excellent operating properties and high density integration capability as a crossbar array. However, the application of the existing ReRAM as a crossbar array may lead to crosstalk between adjacent cells due to its symmetric I- V characteristics. In this study, the self-rectifying effect of contact between amorphous In-Ga-Zn-O (a-IGZO) and TaO x was examined in a Pt/a-IGZO/TaO x /Al2O3/W structure. The experimental results show not only self-rectifying behavior but also forming-free characteristics. During the deposition of a-IGZO on the TaO x , an oxygen-rich TaO x interfacial layer was formed. The rectifying effect was observed regardless of the interface formation and is believed to be associated with Schottky contact formation between a-IGZO and TaO x . The current level remained unchanged despite repeated DC sweep cycles. The low resistance state/high resistance state ratio was about 101 at a read voltage of -0.5 V, and the rectifying ratio was about 103 at ±2 V.

Influence of sweeping detonation-wave loading on damage evolution during spallation loading of tantalum in both a planar and curved geometry

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

Gray, George Thompson III; Hull, Lawrence Mark; Livescu, Veronica

Widespread research over the past five decades has provided a wealth of experimental data and insight concerning the shock hardening, damage evolution, and the spallation response of materials subjected to square-topped shock-wave loading profiles. However, fewer quantitative studies have been conducted on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (unsupported shocks) loading on the shock hardening, damage evolution, or spallation response of materials. Systematic studies quantifying the effect of sweeping-detonation wave loading are yet sparser. In this study, the damage evolution and spallation response of Ta is shown to be critically dependent on the peak shock stress,more » the geometry of the sample (flat or curved plate geometry), and the shock obliquity during sweeping-detonation-wave shock loading. Sweepingwave loading in the flat-plate geometry is observed to: a) yield a lower spall strength than previously documented for 1-D supported-shock-wave loading, b) exhibit increased shock hardening as a function of increasing obliquity, and c) lead to an increased incidence of deformation twin formation with increasing shock obliquity. Sweeping-wave loading of a 10 cm radius curved Ta plate is observed to: a) lead to an increase in the shear stress as a function of increasing obliquity, b) display a more developed level of damage evolution, extensive voids and coalescence, and lower spall strength with obliquity in the curved plate than seen in the flat-plate sweeping-detonation wave loading for an equivalent HE loading, and c) no increased propensity for deformation twin formation with increasing obliquity as seen in the flat-plate geometry. The overall observations comparing and contrasting the flat versus curved sweeping-wave spall experiments with 1D loaded spallation behavior suggests a coupled influence of obliquity and geometry on dynamic shock-induced damage evolution and spall strength. Coupled experimental and modeling research to quantify the combined effects of sweeping-wave loading with increasingly complex sample geometries on the shockwave response of materials is clearly crucial to providing the basis for developing and thereafter validation of predictive modeling capability.« less

Adiabatic description of long range frequency sweeping

NASA Astrophysics Data System (ADS)

Nyqvist, R. M.; Lilley, M. K.; Breizman, B. N.

2012-09-01

A theoretical framework is developed to describe long range frequency sweeping events in the 1D electrostatic bump-on-tail model with fast particle sources and collisions. The model includes three collision operators (Krook, drag (dynamical friction) and velocity space diffusion), and allows for a general shape of the fast particle distribution function. The behaviour of phase space holes and clumps is analysed in the absence of diffusion, and the effect of particle trapping due to separatrix expansion is discussed. With a fast particle distribution function whose slope decays above the resonant phase velocity, hooked frequency sweeping is found for holes in the presence of drag collisions alone.

Facile generation of cell microarrays using vacuum degassing and coverslip sweeping.

PubMed

Wang, Min S; Luo, Zhen; Cherukuri, Sundar; Nitin, Nitin

2014-07-15

A simple method to generate cell microarrays with high-percentage well occupancy and well-defined cell confinement is presented. This method uses a synergistic combination of vacuum degassing and coverslip sweeping. The vacuum degassing step dislodges air bubbles from the microwells, which in turn enables the cells to enter the microwells, while the physical sweeping step using a glass coverslip removes the excess cells outside the microwells. This low-cost preparation method provides a simple solution to generating cell microarrays that can be performed in basic research laboratories and point-of-care settings for routine cell-based screening assays. Copyright © 2014 Elsevier Inc. All rights reserved.

Method for generating a mesh representation of a region characterized by a trunk and a branch thereon

DOEpatents

Shepherd, Jason [Albuquerque, NM; Mitchell, Scott A [Albuquerque, NM; Jankovich, Steven R [Anaheim, CA; Benzley, Steven E [Provo, UT

2007-05-15

The present invention provides a meshing method, called grafting, that lifts the prior art constraint on abutting surfaces, including surfaces that are linking, source/target, or other types of surfaces of the trunk volume. The grafting method locally modifies the structured mesh of the linking surfaces allowing the mesh to conform to additional surface features. Thus, the grafting method can provide a transition between multiple sweep directions extending sweeping algorithms to 23/4-D solids. The method is also suitable for use with non-sweepable volumes; the method provides a transition between meshes generated by methods other than sweeping as well.

The K{sub a}-band 10-kW continuous wave gyrotron with wide-band fast frequency sweep

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

Glyavin, M.; Luchinin, A.; Morozkin, M.

2012-07-15

The dual-frequency gyrotron with fast 2% frequency sweep at about 28 GHz is designed to power an electron cyclotron resonance ion source (ECRIS). Operation with an output power of up to 10 kW in CW mode and efficiency of 20% was demonstrated at both frequencies. Frequency manipulation has a characteristic time of about 1 ms and is based on magnetic field variation with an additional low-power coil. Fast frequency sweep will supposedly increase the ion current and the average ion charge of ECRIS. The possibility of 100% power modulation is demonstrated using the same control method.

Techniques used in the F-14 variable-sweep transition flight experiment

NASA Technical Reports Server (NTRS)

Anderson, Bianca Trujillo; Meyer, Robert R., Jr.; Chiles, Harry R.

1988-01-01

This paper discusses and evaluates the test measurement techniques used to determine the laminar-to-turbulent boundary layer transition location in the F-14 variable-sweep transition flight experiment (VSTFE). The main objective of the VSTFE was to determine the effects of wing sweep on the laminar-to-turbulent transition location at conditions representative of transport aircraft. Four methods were used to determine the transition location: (1) a hot-film anemometer system; (2) two boundary-layer rakes; (3) surface pitot tubes; and (4) liquid crystals for flow visualization. Of the four methods, the hot-film anemometer system was the most reliable indicator of transition.

Electrical Anomalies Observed During DC3

NASA Technical Reports Server (NTRS)

Lang, Timothy J.; Rutledge, Steven A.; Dolan, Brenda; Krehbiel, Paul; Rison, William; Lindsey, Daniel T.; Lyons, Walt

2013-01-01

The primary scientific goals of DC3 involved improving our understanding of the chemical impacts of thunderstorms and their anvils. However, the Colorado domain provided opportunities to study other interesting phenomena, including the potential impacts of smoke ingestion on convection and thunderstorms, electrification processes in smoke plumes and pyrocumulonimbus clouds, and the production of sprites by unconventional thunderstorm.

Feasibility of heart rate variability measurement from quadrature Doppler radar using arctangent demodulation with DC offset compensation.

PubMed

Massagram, Wansuree; Hafner, Noah M; Park, Byung-Kwan; Lubecke, Victor M; Host-Madsen, Anders; Boric-Lubecke, Olga

2007-01-01

This paper describes the experimental results of the beat-to-beat interval measurement from a quadrature Doppler radar system utilizing arctangent demodulation with DC offset compensation techniques. The comparison in SDNN and in RMSDD of both signals demonstrates the potential of using quadrature Doppler radar for HRV analysis.

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.

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.

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

HIV-derived vectors for gene therapy targeting dendritic cells.

PubMed

Rossetti, Maura; Cavarelli, Mariangela; Gregori, Silvia; Scarlatti, Gabriella

2013-01-01

Human immunodeficiency virus type 1 (HIV-1)-derived lentiviral vectors (LV) have the potential to mediate stable therapeutic gene transfer. However, similarly to other viral vectors, their benefit is compromised by the induction of an immune response toward transgene-expressing cells that closely mimics antiviral immunity. LV share with the parental HIV the ability to activate dendritic cells (DC), while lack the peculiar ability of subverting DC functions, which is responsible for HIV immune escape. Understanding the interaction between LV and DC, with plasmacytoid and myeloid DC playing fundamental and distinct roles, has paved the way to novel approaches aimed at regulating transgene-specific immune responses. Thanks to the ability to target either DC subsets LV might be a powerful tool to induce immunity (i.e., gene therapy of cancer), cell death (i.e., in HIV/AIDS infection), or tolerance (i.e., gene therapy strategies for monogenic diseases). In this chapter, similarities and differences between the LV-mediated and HIV-mediated induction of immune responses, with specific focus on their interactions with DC, are discussed.

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.

Optimized efficiency of all-electric ships by dc hybrid power systems

NASA Astrophysics Data System (ADS)

Zahedi, Bijan; Norum, Lars E.; Ludvigsen, Kristine B.

2014-06-01

Hybrid power systems with dc distribution are being considered for commercial marine vessels to comply with new stringent environmental regulations, and to achieve higher fuel economy. In this paper, detailed efficiency analysis of a shipboard dc hybrid power system is carried out. An optimization algorithm is proposed to minimize fuel consumption under various loading conditions. The studied system includes diesel engines, synchronous generator-rectifier units, a full-bridge bidirectional converter, and a Li-Ion battery bank as energy storage. In order to evaluate potential fuel saving provided by such a system, an online optimization strategy for fuel consumption is implemented. An Offshore Support Vessel (OSV) is simulated over different operating modes using the online control strategy. The resulted consumed fuel in the simulation is compared to that of a conventional ac power system, and also a dc power system without energy storage. The results show that while the dc system without energy storage provides noticeable fuel saving compared to the conventional ac system, optimal utilization of the energy storage in the dc system results in twice as much fuel saving.

Using temperature sweeps to investigate rheology of bioplastics

USDA-ARS?s Scientific Manuscript database

As part of research toward production of protein-based bioplastics, small amplitude oscillatory shear analyses were performed in the temperature sweep mode to examine protein blends in the presence of wheat flour and glycerol. The elastic modulus (G') of these samples was much higher than the visco...

Tyrosine decarboxylase activity of enterococci grown in media with different nutritional potential: tyramine and 2-phenylethylamine accumulation and tyrDC gene expression.

PubMed

Bargossi, Eleonora; Tabanelli, Giulia; Montanari, Chiara; Lanciotti, Rosalba; Gatto, Veronica; Gardini, Fausto; Torriani, Sandra

2015-01-01

The ability to accumulate tyramine and 2-phenylethylamine by two strains of Enterococcus faecalis and two strains Enterococcus faecium was evaluated in two cultural media added or not with tyrosine. All the enterococcal strains possessed a tyrosine decarboxylase (tyrDC) which determined tyramine accumulation in all the conditions tested, independently on the addition of high concentration of free tyrosine. Enterococci differed in rate and level of biogenic amines accumulation. E. faecalis EF37 and E. faecium FC12 produced tyramine in high amount since the exponential growth phase, while 2-phenylethylamine was accumulated when tyrosine was depleted. E. faecium FC12 and E. faecalis ATCC 29212 showed a slower tyraminogenic activity which took place mainly in the stationary phase up to 72 h of incubation. Moreover, E. faecalis ATCC 29212 produced 2-phenylethylamine only in the media without tyrosine added. In BHI added or not with tyrosine the tyrDC gene expression level differed considerably depending on the strains and the growth phase. In particular, the tyrDC gene expression was high during the exponential phase in rich medium for all the strains and subsequently decreased except for E. faecium FC12. Even if tyrDC presence is common among enterococci, this study underlines the extremely variable decarboxylating potential of strains belonging to the same species, suggesting strain-dependent implications in food safety.

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.

Elevated serum levels of decoy receptor 3 are associated with disease severity in patients with hemorrhagic fever with renal syndrome.

PubMed

Dong, Yanying; Shi, Dongsha; Li, Man; Dai, Pengfei; Wang, Xiangling; Xie, Ming

2015-08-01

Hemorrhagic fever with renal syndrome (HFRS) is an acute viral infectious disease characterized by fever, hemorrhage and renal failure. HFRS has become a serious public health problem in China. Unfortunately, the pathogenesis of HFRS has not been completely clarified. The aim of this study is to investigate the changes of decoy receptor 3 (DcR3) and to further explore its potential roles in HFRS. The levels of serum DcR3 were measured by sandwich ELISA. We found serum DcR3 levels increased significantly, which reached peak value during the oliguric phase and in the critical group. Moreover, serum DcR3 levels were closely related to the levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and parameters reflecting kidney injury including BUN, creatinine (Cr) and proteinuria. This study indicates that high levels of serum DcR3 have associations with the disease stages, severity and degree of kidney damage. Meanwhile, our results suggest that DcR3 may play a dual role in HFRS pathogenesis. First, DcR3 is involved in the inflammatory cascade response resulting in capillary permeability and kidney injury in the early stage. Secondly, HTNV infection induced DcR3 expression at the convalescent phase may act as a feed-back mechanism in anti-inflammatory response. Thus, a study of DcR3 is essential for a better understanding of HFRS pathogenesis.

Predicting the influence of liposomal lipid composition on liposome size, zeta potential and liposome-induced dendritic cell maturation using a design of experiments approach.

PubMed

Soema, Peter C; Willems, Geert-Jan; Jiskoot, Wim; Amorij, Jean-Pierre; Kersten, Gideon F

2015-08-01

In this study, the effect of liposomal lipid composition on the physicochemical characteristics and adjuvanticity of liposomes was investigated. Using a design of experiments (DoE) approach, peptide-containing liposomes containing various lipids (EPC, DOPE, DOTAP and DC-Chol) and peptide concentrations were formulated. Liposome size and zeta potential were determined for each formulation. Moreover, the adjuvanticity of the liposomes was assessed in an in vitro dendritic cell (DC) model, by quantifying the expression of DC maturation markers CD40, CD80, CD83 and CD86. The acquired data of these liposome characteristics were successfully fitted with regression models, and response contour plots were generated for each response factor. These models were applied to predict a lipid composition that resulted in a liposome with a target zeta potential. Subsequently, the expression of the DC maturation factors for this lipid composition was predicted and tested in vitro; the acquired maturation responses corresponded well with the predicted ones. These results show that a DoE approach can be used to screen various lipids and lipid compositions, and to predict their impact on liposome size, charge and adjuvanticity. Using such an approach may accelerate the formulation development of liposomal vaccine adjuvants. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Optimal MEMS device for mobility and zeta potential measurements using DC electrophoresis.

PubMed

Karam, Pascal R; Dukhin, Andrei; Pennathur, Sumita

2017-05-01

We have developed a novel microchannel geometry that allows us to perform simple DC electrophoresis to measure the electrophoretic mobility and zeta potential of analytes and particles. In standard capillary geometries, mobility measurements using DC fields are difficult to perform. Specifically, measurements in open capillaries require knowledge of the hard to measure and often dynamic wall surface potential. Although measurements in closed capillaries eliminate this requirement, the measurements must be performed at infinitesimally small regions of zero flow where the pressure driven-flow completely cancels the electroosmotic flow (Komagata Planes). Furthermore, applied DC fields lead to electrode polarization, further questioning the reliability and accuracy of the measurement. In contrast, our geometry expands and moves the Komagata planes to where velocity gradients are at a minimum, and thus knowledge of the precise location of a Komagata plane is not necessary. Additionally, our microfluidic device prevents electrode polarization because of fluid recirculation around the electrodes. We fabricated our device using standard MEMS fabrication techniques and performed electrophoretic mobility measurements on 500 nm fluorescently tagged polystyrene particles at various buffer concentrations. Results are comparable to two different commercial dynamic light scattering based particle sizing instruments. We conclude with guidelines to further develop this robust electrophoretic tool that allows for facile and efficient particle characterization. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Earthquake hazard potential in the Eastern Anatolian Region of Turkey: seismotectonic b and Dc-values and precursory quiescence Z-value

NASA Astrophysics Data System (ADS)

Öztürk, S.

2018-03-01

The Eastern Anatolian Region of Turkey is one of the most seismically and tectonically active regions due to the frequent occurrence of earthquakes. Thus, the main goal of this study is to analyze the regional and temporal characteristics of seismicity in the Eastern Anatolia in terms of the seismotectonic b-value, fractal dimension Dc-value, precursory seismic quiescence Z-value, and their interrelationships. This study also seeks to obtain a reliable empirical relation between b and Dc-values and to evaluate the temporal changes of these parameters as they relate to the earthquake potential of the region. A more up-to-date relation of Dc = 2:55-0:39* b is found with a very strong negative correlation coefficient ( r =-0.95) by using the orthogonal regression method. The b-values less than 1.0 and the Dc-values greater than 2.2 are observed in the Northeast Anatolian Fault Zone, Aşkale, Erzurum, Iğdır and Çaldıran Faults, Doğubeyazıt Fault Zone, around the Genç Fault, the western part of the Bitlis-Zagros Thrust Zone, Pülümür and Karakoçan Faults, and the Sancak- Uzunpınar Fault Zone. In addition, the regions having small b-values and large Z-values are calculated around the Genç, Pülümür and Karakoçan Faults as well as the Sancak-Uzunpınar Fault Zone. Remarkably, the combinations of these seismotectonic parameters could reveal the earthquake hazard potential in the Eastern Anatolian Region of Turkey, thus creating an increased interest in these anomaly regions.

Sweep Width Estimation for Ground Search and Rescue

DTIC Science & Technology

2004-12-30

Develop data compatible with search planning and POD estimation methods that are de- signed to use sweep width data. An experimental...important for Park Rangers and man- trackers . Search experience was expected to be a significant correction factor. However, the re- sults indicate...41 4.1.1 Signing In

Minimization of the Effects of Secondary Reactions on Turbine Film Cooling in a Fuel Rich Environment

DTIC Science & Technology

2014-06-02

the instrumentation block ..................................... 57 Table 4.1: Flame Length Results...91 Table 4.2: Five Row Flame Lengths , Blowing Ratio Sweep .......................................... 123 Table...4.3: Five Row Flame Lengths , Equivalence Ratio Sweep .................................... 124 Table 4.4: Five Row - Wall Absorption Parameter

Building the Workforce of the Future

ERIC Educational Resources Information Center

González-Rivera, Christian

2016-01-01

"Building the Workforce of the Future" is an in-depth, independent report on the first eighteen months of Career Pathways, New York City's sweeping new strategy for workforce development. In November 2014, Mayor de Blasio launched a sweeping new approach to workforce development in New York City. Unlike the previous model, which…

Student-Loan Investigation Sweeps Up More Colleges

ERIC Educational Resources Information Center

Basken, Paul; Field, Kelly

2007-01-01

An expanding investigation into conflicts of interest in the student-loan industry continued to sweep up more lenders and college financial-aid administrators last week. The nation's largest student-loan provider, Sallie Mae, accepted a $2-million settlement with New York State's attorney general, Andrew M. Cuomo, and three more college officials…

An Investigation of the Nontechnical Skills Required to Maximize the Safety and Productivity of U.S. Navy Divers

DTIC Science & Technology

2005-04-01

experience. The critical incident interview uses recollection of a specific incident as its starting point and employs a semistructured interview format...context assessment, expectancies, and judgments. The four sweeps in the critical incident interview include: Sweep 1 - Prompting the interviewee to

Visualization of hair follicles using high-speed optical coherence tomography based on a Fourier domain mode locking laser

NASA Astrophysics Data System (ADS)

Tsai, M.-T.; Chang, F.-Y.

2012-04-01

In this study, a swept-source optical coherence tomography (SS-OCT) system with a Fourier domain mode locking (FDML) laser is proposed for a dermatology study. The homemade FDML laser is one kind of frequency-sweeping light source, which can provide output power of >20 mW and an output spectrum of 65 nm in bandwidth centered at 1300 nm, enabling imaging with an axial resolution of 12 μm in the OCT system. To eliminate the forward scans from the laser output and insert the delayed backward scans, a Mach-Zehnder configuration is implemented. Compared with conventional frequency-sweeping light sources, the FDML laser can achieve much higher scan rates, as high as ˜240 kHz, which can provide a three-dimensional imaging rate of 4 volumes/s. Furthermore, the proposed high-speed SS-OCT system can provide three-dimensional (3D) images with reduced motion artifacts. Finally, a high-speed SS-OCT system is used to visualize hair follicles, demonstrating the potential of this technology as a tool for noninvasive diagnosis of alopecia.

The influence of the use of viscosifying agents as dispersion media on the drug release properties from PLGA nanoparticles.

PubMed

Dillen, Kathleen; Weyenberg, Wim; Vandervoort, Jo; Ludwig, Annick

2004-11-01

Poly(lactide-co-glycolide) nanoparticles incorporating ciprofloxacin HCl were prepared by means of a W/O/W emulsification solvent evaporation method. The physicochemical properties of these particles were evaluated by measuring particle size, zeta potential and drug loading efficiency. Gamma-sterilised nanoparticles were dispersed in different isoviscous polymer solutions, commonly used as vehicles in eye drops. The influence of gamma-irradiation of the viscosifying agents on the drug release properties of the dispersed nanoparticles was evaluated with respect to release in mannitol solution. The viscosity of the polymer solutions prepared was measured by flow rheometry and thereby the influence of temperature and sterilisation by autoclaving on viscosity was examined. Before and after freeze-drying and subsequent sterilisation by gamma-irradiation, the polymer solutions were also characterised by dynamic stress sweep and dynamic frequency sweep oscillation measurements to deduce possible structural changes. A possible relationship between the differences in ciprofloxacin release from the nanoparticles suspended in the various media and the network structure or rheological behaviour of the polymers was investigated.

Aeroelastic modeling of composite rotor blades with straight and swept tips

NASA Technical Reports Server (NTRS)

Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

1992-01-01

This paper presents an analytical study of the aeroelastic behavior of composite rotor blades with straight and swept tips. The blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. The nonlinear equations of motion for the FEM are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. It is shown that composite ply orientation has a substantial effect on blade stability. At low thrust conditions, certain ply orientations can cause instability in the lag mode. The flap-torsion coupling associated with tip sweep can also induce aeroelastic instability in the blade. This instability can be removed by appropriate ply orientation in the composite construction. These results illustrate the inherent potential for aeroelastic tailoring present in composite rotor blades with swept tips, which still remains to be exploited in the design process.

Potential damage to dc superconducting magnets due to high frequency electromagnetic waves

NASA Technical Reports Server (NTRS)

Gabriel, G. J.; Burkhart, J. A.

1977-01-01

Studies of a d.c. superconducting magnet coil indicate that the large coil behaves as a straight waveguide structure. Voltages between layers within the coil sometimes exceeded those recorded at terminals where protective resistors are located. Protection of magnet coils against these excessive voltages could be accomplished by impedance matching throughout the coil system. The wave phenomenon associated with superconducting magnetic coils may create an instability capable of converting the energy of a quiescent d.c. superconducting coil into dissipative a.c. energy, even in cases when dielectric breakdown does not take place.

Influence of two-electrode montages on the level-specific (LS) CE-Chirp auditory brainstem response (ABR) at multiple intensity levels.

PubMed

Dzulkarnain, Ahmad Aidil Arafat; Noor Ibrahim, Siti Hajra Mu'minah; Anuar, Nur Farah Aida; Abdullah, Siti Aisyah; Tengku Zam Zam, Tengku Zulaila Hasma; Rahmat, Sarah; Mohd Ruzai, Muhammad Amar

2017-10-01

To investigate the influence of two different electrode montages (ipsilateral: reference to mastoid and vertical: reference to nape of neck) to the ABR results recorded using a level-specific (LS)-CE-Chirp® in normally hearing subjects at multiple intensities levels. Quasi-experimental and repeated measure study designs were applied in this study. Two different stopping criteria were used, (1) a fixed-signal averaging 4000 sweeps and, (2) a minimum quality indicator of Fmp = 3.1 with a minimum of 800 sweeps. Twenty-nine normally hearing adults (18 females, 11 male) participated. Wave V amplitudes were significantly larger in the LS CE-Chirp® recorded from the vertical montage than the ipsilateral montage. Waves I and III amplitudes were significantly larger from the ipsilateral LS CE-Chirp® than from the other montages and stimulus combinations. The differences in the quality of the ABR recording between the vertical and ipsilateral montages were marginal. Overall, the result suggested that the vertical LS CE-Chirp® ABR had a high potential for a threshold-seeking application, because it produced a higher wave V amplitude. The Ipsilateral LS CE-Chirp® ABR, on the other hand, might also have a high potential for the site of lesion application, because it produced larger waves I and III amplitudes.

High-dose HOOK effect in urinary DcR2 assay in patients with chronic kidney disease.

PubMed

Chen, Jia; Chen, Ke-Hong; Wang, Li-Ming; Zhang, Wei-Wei; Feng, Lei; Dai, Huan-Zi; He, Ya-Ni

2018-06-05

Urinary DcR2 (uDcR2) is a biomarker for the early detection the tubulointerstitial injury (TII) in patients with chronic kidney disease (CKD), but the high-dose hook effect may lead to falsely low or even negative results when using an enzyme-linked immunosorbent assay (ELISA). This study aimed to investigate if the high-dose hook effect exists with ELISA testing, and to uncover a potential approach for reducing this effect. 72 CKD patients were recruited and categorized into four groups based on TII scores. uDcR2 was measured in undiluted and serially diluted (two-, four-, eight- and 16-fold dilutions) urine using an ELISA kit. The results from the assay were normalized to urinary creatinine. We evaluated the correlation between uDcR2/cre levels at different dilutions and renal histological parameters. Receiver operating characteristic (ROC) curves were generated to examine the value of uDcR2/cre for predicting TII. uDcR2/cre levels in the undiluted urine were significantly higher in patients with CKD than those in the control. However, higher TII scores did not yield higher levels of uDcR2/cre in the undiluted urine. After serial dilution, uDcR2/cre levels were highest with the four-fold dilution. A positive correlation was found between uDcR2/cre levels at different dilutions and TII scores, with the highest correlation coefficient and the largest AUC being observed at the four-fold dilution. The high-dose hook effect was apparent during ELISA testing of uDcR2 in CKD patients, yet dilution of the urine samples neutralized this effect. However, the use of a four-fold dilution of urine for uDcR2/cre testing may eliminate the high-dose hook effect and make it possible to effectively monitor the severity of TII in CKD patients. Copyright © 2018. Published by Elsevier Inc.

Impact of tobacco smoke on upper airway dendritic cell accumulation and regulation by sinonasal epithelial cells.

PubMed

Mulligan, Jennifer K; O'Connell, Brendan P; Pasquini, Whitney; Mulligan, Ryan M; Smith, Sarah; Soler, Zachary M; Atkinson, Carl; Schlosser, Rodney J

2017-08-01

In these studies we examined the impact of environmental tobacco smoke (ETS) and active smoking on sinonasal dendritic cell (DC) subsets in controls or patients with chronic rhinosinusitis with nasal polyps (CRSwNP). In subsequent in-vitro investigations, we examined the influence of cigarette smoke extract (CSE) on human sinonasal epithelial cells' (HSNECs) ability to regulate DC functions. Sinonasal tissue, blood, and hair were collected from patients undergoing sinus surgery. Smoking status and ETS exposure were determined by hair nicotine. DC subsets were examined by flow cytometric analysis. Monocyte-derived dendritic cells (moDCs) were treated with conditioned medium from non-smoked-exposed HSNECs (NS-HSNECs) or cigarette-smoke-extract-exposed HSNECs (CSE-HSNECs) to assess the impact of CSE exposure on HSNEC regulation of moDC functions. Control subjects who were active smokers displayed increased sinonasal moDC and myeloid dendritic 1 (mDC1) cells and reduced mDC2 cells, whereas, in CRSwNP patients, only moDC and mDC2 cells were altered. ETS was found to increase only moDCs in the CRSwNP patients. In vitro, CSE stimulated HSNEC secretion of the moDC regulatory products chemokine (C-C motif) ligand 20, prostaglandin E 2 , and granulocyte-macrophage colony-stimulating factor. CSE exposure also promoted HSNECs to stimulate monocyte and moDC migration. moDCs treated with CSE-HSNEC media stimulated an increase in antigen uptake and expression of CD80 and CD86. Last, CSE-HSNEC-treated moDCs secreted increased levels of interleukin-10, interferon-γ, and thymic stromal lymphopoietin. Active smoking, and to a lesser degree ETS, alters the sinonasal composition of DCs. A potential mechanism to account for this is that cigarette smoke stimulates HSNECs to induce moDC migration, maturation, and activation. © 2017 ARS-AAOA, LLC.

Differential cytotoxicity of long-chain bases for human oral gingival epithelial keratinocytes, oral fibroblasts, and dendritic cells

PubMed Central

Mehalick, Leslie A.; Poulsen, Christopher; Fischer, Carol L.; Lanzel, Emily A.; Bates, Amber M.; Walters, Katherine S.; Cavanaugh, Joseph E.; Guthmiller, Janet M.; Johnson, Georgia K.; Wertz, Philip W.; Brogden, Kim A.

2015-01-01

Long-chain bases, found in the oral cavity, have potent antimicrobial activity against oral pathogens. In an article associated with this dataset, Poulson and colleagues determined the cytotoxicities of long-chain bases (sphingosine, dihydrosphingosine, and phytosphingosine) for human oral gingival epithelial (GE) keratinocytes, oral gingival fibroblasts (GF), dendritic cells (DC), and squamous cell carcinoma (SCC) cell lines [1]. Poulson and colleagues found that GE keratinocytes were more resistant to long-chain bases as compared to GF, DC, and SCC cell lines [1]. In this study, we assess the susceptibility of DC to lower concentrations of long chain bases. 0.2–10.0 µM long-chain bases and GML were not cytotoxic to DC; 40.0–80.0 µM long-chain bases, but not GML, were cytotoxic for DC; and 80.0 µM long-chain bases were cytotoxic to DC and induced cellular damage and death in less than 20 mins. Overall, the LD50 of long-chain bases for GE keratinocytes, GF, and DC were considerably higher than their minimal inhibitory concentrations for oral pathogens, a finding important to pursuing their future potential in treating periodontal and oral infections. PMID:26550599

Apoptosis and dysfunction of blood dendritic cells in patients with falciparum and vivax malaria

PubMed Central

Woodberry, Tonia; Kienzle, Vivian; McPhun, Virginia; Minigo, Gabriela; Lampah, Daniel A.; Kenangalem, Enny; Engwerda, Christian; López, J. Alejandro; Anstey, Nicholas M.

2013-01-01

Malaria causes significant morbidity worldwide and a vaccine is urgently required. Plasmodium infection causes considerable immune dysregulation, and elicitation of vaccine immunity remains challenging. Given the central role of dendritic cells (DCs) in initiating immunity, understanding their biology during malaria will improve vaccination outcomes. Circulating DCs are particularly important, as they shape immune responses in vivo and reflect the functional status of other subpopulations. We performed cross-sectional and longitudinal assessments of the frequency, phenotype, and function of circulating DC in 67 Papuan adults during acute uncomplicated P. falciparum, P. vivax, and convalescent P. falciparum infections. We demonstrate that malaria patients display a significant reduction in circulating DC numbers and the concurrent accumulation of immature cells. Such alteration is associated with marked levels of spontaneous apoptosis and impairment in the ability of DC to mature, capture, and present antigens to T cells. Interestingly, sustained levels of plasma IL-10 were observed in patients with acute infection and were implicated in the induction of DC apoptosis. DC apoptosis was reversed upon IL-10 blockade, and DC function recovered when IL-10 levels returned to baseline by convalescence. Our data provide key information on the mechanisms behind DC suppression during malaria and will assist in developing strategies to better harness DC’s immunotherapeutic potential. PMID:23835848

Phenomenological study of subsonic turbulent flow over a swept rearward-facing step. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Selby, G. V.

1982-01-01

The phenomenology of turbulent, subsonic flow over a swept, rearward-facing step was studied. Effects of variations in step height, sweep angle, base geometry, and end conditions on the 3-D separated flow were examined. The separated flow was visualized using smoke wire, oil drop, and surface tuft techniques. Measurements include surface pressure, reattachment distance and swirl angle. Results indicate: (1) model/test section coupling affects the structure of the separated flow, but spanwise end conditions do not; (2) the independence principle is evidently valid for sweep angles up to 38 deg; (3) a sweep angle/swirl angle correlation exists; and (4) base modifications can significantly reduce the reattachment distance.

Study of Effects of Sweep on the Flutter of Cantilever Wings

NASA Technical Reports Server (NTRS)

Barmby, J G; Cunningham, H J; Garrick, I E

1951-01-01

An experimental and analytical investigation of the flutter of sweptback cantilever wings is reported. The experiments employed groups of wings swept back by rotating and by shearing. The angle of sweep range from 0 degree to 60 degrees and Mach numbers extended to approximately 0.85. A theoretical analysis of the air forces on an oscillating swept wing of high length-chord ratio is developed, and the approximations inherent in the assumptions are discussed. Comparison with experiment indicates that the analysis developed in the present report is satisfactory for giving the main effects of sweep, at least for nearly uniform cantilever wings of high and moderate length-chord ratios.

Kinetic Monte Carlo simulations of thermally activated magnetization reversal in dual-layer Exchange Coupled Composite recording media

NASA Astrophysics Data System (ADS)

Plumer, M. L.; Almudallal, A. M.; Mercer, J. I.; Whitehead, J. P.; Fal, T. J.

The kinetic Monte Carlo (KMC) method developed for thermally activated magnetic reversal processes in single-layer recording media has been extended to study dual-layer Exchange Coupled Composition (ECC) media used in current and next generations of disc drives. The attempt frequency is derived from the Langer formalism with the saddle point determined using a variant of Bellman Ford algorithm. Complication (such as stagnation) arising from coupled grains having metastable states are addressed. MH-hysteresis loops are calculated over a wide range of anisotropy ratios, sweep rates and inter-layer coupling parameter. Results are compared with standard micromagnetics at fast sweep rates and experimental results at slow sweep rates.

Laryngeal flow due to longitudinal sweeping motion of the vocal folds and its contribution to auto-oscillation.

PubMed

Boutin, Henri; Smith, John; Wolfe, Joe

2015-07-01

Analysis of published depth-kymography data [George, de Mul, Qiu, Rakhorst, and Schutte (2008). Phys. Med. Biol. 53, 2667-2675] shows that, for the subject studied, the flow due to the longitudinal sweeping motion of the vocal folds contributes several percent of a typical acoustic flow at the larynx. This sweeping flow is a maximum when the glottis is closed. This observation suggests that assumption of zero laryngeal flow during the closed phase as a criterion when determining parameters in inverse filtering should be used with caution. Further, these data suggest that the swinging motion contributes work to overcome mechanical losses and thus to assist auto-oscillation.

Gate frequency sweep: An effective method to evaluate the dynamic performance of AlGaN/GaN power heterojunction field effect transistors

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

Santi, C. de; Meneghini, M., E-mail: matteo.meneghini@dei.unipd.it; Meneghesso, G.

2014-08-18

With this paper we propose a test method for evaluating the dynamic performance of GaN-based transistors, namely, gate-frequency sweep measurements: the effectiveness of the method is verified by characterizing the dynamic performance of Gate Injection Transistors. We demonstrate that this method can provide an effective description of the impact of traps on the transient performance of Heterojunction Field Effect Transistors, and information on the properties (activation energy and cross section) of the related defects. Moreover, we discuss the relation between the results obtained by gate-frequency sweep measurements and those collected by conventional drain current transients and double pulse characterization.

Federal policy and the rise in disability enrollment: evidence for the Veterans Affairs' Disability Compensation Program.

PubMed

Duggan, Mark; Rosenheck, Robert; Singleton, Perry

2010-01-01

The U.S. Department of Veterans Affairs compensates 13 percent of the nation’s military veterans for service‐related disabilities through the Disability Compensation (DC) program. In 2001, a legislative change made it easier for Vietnam veterans to receive benefits for diabetes associated with military service. In this paper, we investigate this policy’s effect on DC enrollment and expenditures as well as the behavioral response of potential beneficiaries. Our findings demonstrate that the policy increased DC enrollment by 6 percentage points among Vietnam veterans and that an additional 1.7 percent experienced an increase in their DC benefits, which increased annual program expenditures by $2.85 billion in 2007. Using individual-level data from the Veterans Supplement to the Current Population Survey, we find that the induced increase in DC enrollment had little average impact on the labor supply or health status of Vietnam veterans but did reduce labor supply among their spouses.

Multilayered dense collagen-silk fibroin hybrid: a platform for mesenchymal stem cell differentiation towards chondrogenic and osteogenic lineages.

PubMed

Ghezzi, Chiara E; Marelli, Benedetto; Donelli, Ilaria; Alessandrino, Antonio; Freddi, Giuliano; Nazhat, Showan N

2017-07-01

Type I collagen is a major structural and functional protein in connective tissues. However, collagen gels exhibit unstable geometrical properties, arising from extensive cell-mediated contraction. In an effort to stabilize collagen-based hydrogels, plastic compression was used to hybridize dense collagen (DC) with electrospun silk fibroin (SF) mats, generating multilayered DC-SF-DC constructs. Seeded mesenchymal stem cell (MSC)-mediated DC-SF-DC contraction, as well as growth and differentiation under chondrogenic and osteogenic supplements, were compared to those seeded in DC and on SF alone. The incorporation of SF within DC prevented extensive cell-mediated collagen gel contraction. The effect of the multilayered hybrid on MSC remodelling capacity was also evident at the transcription level, where the expression of matrix metalloproteinases and their inhibitor (MMP1, MMP2, MMP3, MMP13 and Timp1) by MSCs within DC-SF-DC were comparable to those on SF and significantly downregulated in comparison to DC, except for Timp1. Chondrogenic supplements stimulated extracellular matrix production within the construct, stabilizing its multilayered structure and promoting MSC chondrogenic differentiation, as indicated by the upregulation of the genes Col2a1 and Agg and the production of collagen type II. In osteogenic medium there was an upregulation in ALP and OP along with the presence of an apatitic phase, indicating MSC osteoblastic differentiation and matrix mineralization. In sum, these results have implications on the modulation of three-dimensional collagen-based gel structural stability and on the stimulation and maintenance of the MSC committed phenotype inherent to the in vitro formation of chondral tissue and bone, as well as on potential multilayered complex tissues. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Identification and molecular profiling of DC-SIGN-like from big belly seahorse (Hippocampus abdominalis) inferring its potential relevancy in host immunity.

PubMed

Jo, Eunyoung; Elvitigala, Don Anushka Sandaruwan; Wan, Qiang; Oh, Minyoung; Oh, Chulhong; Lee, Jehee

2017-12-01

Dendritic-cell-specific ICAM-3-grabbing non-integrin (DC-SIGN) is a C-type lectin that functions as a pattern recognition receptor by recognizing pathogen-associated molecular patterns (PAMPs). It is also involved in various events of the dendritic cell (DC) life cycle, such as DC migration, antigen capture and presentation, and T cell priming. In this study, a DC-SIGN-like gene from the big belly seahorse Hippocampus abdominalis (designated as ShDCS-like) was identified and molecularly characterized. The putative, complete ORF was found to be 1368 bp in length, encoding a protein of 462 amino acids with a molecular mass of 52.6 kDa and a theoretical isoelectric point of 8.26. The deduced amino acid sequence contains a single carbohydrate recognition domain (CRD), in which six conserved cysteine residues and two Ca 2+ -binding site motifs (QPN, WND) were identified. Based on pairwise sequence analysis, ShDCS-like exhibits the highest amino acid identity (94.6%) and similarity (97.4%) with DC-SIGN-like counterpart from tiger tail seahorse Hippocampus comes. Quantitative real-time PCR revealed that ShDCS-like mRNA is transcribed universally in all tissues examined, but with abundance in kidney and gill tissues. The basal mRNA expression of ShDCS-like was modulated in blood cell, kidney, gill and liver tissues in response to the stimulation of healthy fish with lipopolysaccharides (LPS), Edwardsiella tarda, or Streptococcus iniae. Moreover, recombinant ShDCS-like-CRD domain exhibited detectable agglutination activity against different bacteria. Collectively, these results suggest that ShDCS-like may potentially involve in immune function in big belly seahorses. Copyright © 2017 Elsevier Ltd. All rights reserved.

Serum decoy receptor 3, a potential new biomarker for sepsis.

PubMed

Hou, Yan-Qiang; Xu, Ping; Zhang, Mei; Han, Deping; Peng, Liang; Liang, Dong-Yu; Yang, Shanmin; Zhang, Zhenhuan; Hong, Jinsheng; Lou, Xiao-Li; Zhang, Lurong; Kim, Sunghee

2012-04-11

Sepsis, a common deadly systemic infection caused by a variety of pathogens, has some clinical symptoms similar to the systemic inflammatory response syndrome (SIRS), a whole-body non-infectious inflammatory reaction to severe insults, such as burn, trauma, hypotensive shock and so on. Treatment of sepsis depends mainly on anti-microbial, while remedy for SIRS might require steroids that could possibly enhance the spread of microbes. Unfortunately, it is very difficult to distinguish these two completely different serious conditions without blood culture, which takes days to grow and identify causative pathogens. We examined a biomarker, serum decoy receptor 3 (DcR3), was evaluated for its utility in the differential diagnosis between sepsis and SIRS. Serum DcR3 level in 118 healthy controls, 24 sepsis patients and 43 SIRS patients, was quantitatively measured by enzyme-linked immunosorbent assay (ELISA). The serum DcR3 was significantly increased in sepsis patients compared with SIRS patients and healthy controls (6.11±2.58 ng/ml vs 2.62±1.46 ng/ml, and 0.91±0.56 ng/ml, respectively, p<0.001). The areas under the receiver operating characteristic curve of DcR3 for the normal vs. SIRS, normal vs. sepsis and SIRS vs. sepsis were 0.910 (0.870-0.950), 0.992 (0.984-1.000) and 0.896 (0.820-0.973), respectively. In addition, the DcR3 exhibited a positive correlation coefficient with APACHE II score, a most commonly used index for the severity of sepsis (r=0.556, p=0.005). The serum DcR3 has a potential to serve as a new biomarker for sepsis with its high specificity and sensitivity. Copyright © 2012 Elsevier B.V. All rights reserved.

Recovery from simulated sawn logs with sweep.

Treesearch

Robert A. Monserud; Dean L. Parry; Christine L. Todoroki

2004-01-01

A sawing simulator, AUTOSAW, was used to examine the effect of increasing sweep on lumber recovery. Sample material consisted of 51 logs from 22 western hemlock (Tsuga heterophylla (Raf.) Sarg. ) trees in western Oregon, United States. All knots on the 4.9-m logs were measured, mapped, and converted into 3-dimensional digital formats. The digital...

Performance of the SWEEP model affected by estimates of threshold friction velocity

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) is a process-based model and needs to be verified under a broad range of climatic, soil, and management conditions. Occasional failure of the WEPS erosion submodel (Single-event Wind Erosion Evaluation Program or SWEEP) to simulate erosion in the Columbia Pl...

Comparison of measured and simulated friction velocity and threshold friction velocity using SWEEP

USDA-ARS?s Scientific Manuscript database

The Wind Erosion Prediction System (WEPS) was developed by the USDA Agricultural Research Service as a tool to predict wind erosion and assess the influence of control practices on windblown soil loss. Occasional failure of the WEPS erosion submodel (SWEEP) to simulate erosion in the Columbia Platea...

Automatic sweep circuit

DOEpatents

Keefe, Donald J.

1980-01-01

An automatically sweeping circuit for searching for an evoked response in an output signal in time with respect to a trigger input. Digital counters are used to activate a detector at precise intervals, and monitoring is repeated for statistical accuracy. If the response is not found then a different time window is examined until the signal is found.

Pectin from Husk Tomato (Physalis ixocarpa Brot.): Rheological behavior at different extraction conditions.

PubMed

Morales-Contreras, Blanca E; Rosas-Flores, Walfred; Contreras-Esquivel, Juan C; Wicker, Louise; Morales-Castro, Juliana

2018-01-01

A rheological study was carried out to evaluate formulations of test dispersions and gels of high methoxyl pectins (HTHMP) obtained at different conditions from husk tomato waste (Physalis ixocarpa Brot.). The effect of extraction agent (hydrochloric acid or citric acid), blanching time (10 or 15min) and extraction time (15, 20 or 25min) on the rheology of the tested samples was evaluated. Flow behavior and activation energy were evaluated on the test dispersions, while (E a ) frequency sweeps, temperature sweep, creep-recovery test and penetration test were performed on the gels. HTHMP dispersions showed shear thinning flow behavior, while showing a good fit to Cross model. Extraction agent, blanching time and extraction time did not have effect on Cross parameters (η z , η∞, C, and m). E a decreased as blanching time and extraction time increased. Frequency sweeps revealed high dependence on frequency for both G' and G", while temperature sweeps (25- 95°C) showed thermostable husk tomato pectin gels. Hydrocloric acid (HCl) extracted pectin gels showed stronger structure than citric acid (CA) gels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phase stability analysis of chirp evoked auditory brainstem responses by Gabor frame operators.

PubMed

Corona-Strauss, Farah I; Delb, Wolfgang; Schick, Bernhard; Strauss, Daniel J

2009-12-01

We have recently shown that click evoked auditory brainstem responses (ABRs) can be efficiently processed using a novelty detection paradigm. Here, ABRs as a large-scale reflection of a stimulus locked neuronal group synchronization at the brainstem level are detected as novel instance-novel as compared to the spontaneous activity which does not exhibit a regular stimulus locked synchronization. In this paper we propose for the first time Gabor frame operators as an efficient feature extraction technique for ABR single sweep sequences that is in line with this paradigm. In particular, we use this decomposition technique to derive the Gabor frame phase stability (GFPS) of sweep sequences of click and chirp evoked ABRs. We show that the GFPS of chirp evoked ABRs provides a stable discrimination of the spontaneous activity from stimulations above the hearing threshold with a small number of sweeps, even at low stimulation intensities. It is concluded that the GFPS analysis represents a robust feature extraction method for ABR single sweep sequences. Further studies are necessary to evaluate the value of the presented approach for clinical applications.

Advances in Digital Calibration Techniques Enabling Real-Time Beamforming SweepSAR Architectures

NASA Technical Reports Server (NTRS)

Hoffman, James P.; Perkovic, Dragana; Ghaemi, Hirad; Horst, Stephen; Shaffer, Scott; Veilleux, Louise

2013-01-01

Real-time digital beamforming, combined with lightweight, large aperture reflectors, enable SweepSAR architectures, which promise significant increases in instrument capability for solid earth and biomass remote sensing. These new instrument concepts require new methods for calibrating the multiple channels, which are combined on-board, in real-time. The benefit of this effort is that it enables a new class of lightweight radar architecture, Digital Beamforming with SweepSAR, providing significantly larger swath coverage than conventional SAR architectures for reduced mass and cost. This paper will review the on-going development of the digital calibration architecture for digital beamforming radar instrument, such as the proposed Earth Radar Mission's DESDynI (Deformation, Ecosystem Structure, and Dynamics of Ice) instrument. This proposed instrument's baseline design employs SweepSAR digital beamforming and requires digital calibration. We will review the overall concepts and status of the system architecture, algorithm development, and the digital calibration testbed currently being developed. We will present results from a preliminary hardware demonstration. We will also discuss the challenges and opportunities specific to this novel architecture.

Airloads Correlation of the UH-60A Rotor Inside the 40- by 80-Foot Wind Tunnel

NASA Technical Reports Server (NTRS)

Chang, I-Chung; Norman, Thomas R.; Romander, Ethan A.

2013-01-01

The presented research validates the capability of a loosely-coupled computational fluid dynamics (CFD) and comprehensive rotorcraft analysis (CRA) code to calculate the flowfield around a rotor and test stand mounted inside a wind tunnel. The CFD/CRA predictions for the full-scale UH-60A Airloads Rotor inside the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel at NASA Ames Research Center are compared with the latest measured airloads and performance data. The studied conditions include a speed sweep at constant lift up to an advance ratio of 0.4 and a thrust sweep at constant speed up to and including stall. For the speed sweep, wind tunnel modeling becomes important at advance ratios greater than 0.37 and test stand modeling becomes increasingly important as the advance ratio increases. For the thrust sweep, both the wind tunnel and test stand modeling become important as the rotor approaches stall. Despite the beneficial effects of modeling the wind tunnel and test stand, the new models do not completely resolve the current airload discrepancies between prediction and experiment.

Non-Kinetic Losses Caused by Electrochemical Carbon Corrosion in PEM Fuel Cells

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

Park, Seh Kyu; Shao, Yuyan; Viswanathan, Vilayanur V.

2012-05-01

This paper presented non-kinetic losses in PEM fuel cells under an accelerated stress test of catalyst support. The cathode with carbon-supported Pt catalyst was prepared and characterized with potential hold at 1.2 V vs. SHE in PEM fuel cells. Irreversible losses caused by carbon corrosion were evaluated using a variety of electrochemical characterizations including cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy, and polarization technique. Ohmic losses at the cathode with potential hold were determined using its capacitive responses. Concentration losses in PEM fuel cells were analyzed in terms of Tafel behavior and thin film/flooded-agglomerate dynamics.

Electromagnetic Flow Meter Having a Driver Circuit Including a Current Transducer

NASA Technical Reports Server (NTRS)

Patel, Sandeep K. (Inventor); Karon, David M. (Inventor); Cushing, Vincent (Inventor)

2014-01-01

An electromagnetic flow meter (EMFM) accurately measures both the complete flow rate and the dynamically fluctuating flow rate of a fluid by applying a unipolar DC voltage to excitation coils for a predetermined period of time, measuring the electric potential at a pair of electrodes, determining a complete flow rate and independently measuring the dynamic flow rate during the "on" cycle of the DC excitation, and correcting the measurements for errors resulting from galvanic drift and other effects on the electric potential. The EMFM can also correct for effects from the excitation circuit induced during operation of the EMFM.

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

Testing inferior colliculus neurons for selectivity to the rate or duration of frequency modulated sweeps

NASA Astrophysics Data System (ADS)

Faure, Paul A.; Morrison, James A.; Valdizón-Rodríguez, Roberto

2018-05-01

Here we propose a method for testing how the responses of so-called "FM duration-tuned neurons (DTNs)" encode temporal properties of frequency modulated (FM) sweeps to determine if the responses of so-called "FM duration-tuned neurons (DTNs)" are tuned to FM rate or FM duration. Based on previous studies it was unclear if the responses of "FM DTNs" were tuned to signal duration, like pure-tone DTNs, or FM sweep rate. We tested this using single-unit extracellular recording in the inferior colliculus (IC) of the big brown bat (Eptesicus fuscus). We presented IC cells with linear FM sweeps that were varied in FM center frequency (CEF) and spectral bandwidth (BW) to measure the FM rate tuning responses of a cell. We also varied FM signal duration to measure the best duration (BD) and temporal BW of duration tuning of a cell. We then doubled (and halved) the best FM BW, while keeping the CEF constant, and remeasured the BD and temporal BW of duration tuning with FM bandwidth manipulated signals. We reasoned that the range of excitatory signal durations should not change in a true FM DTN whose responses are tuned to signal duration; however, when stimulated with bandwidth manipulated FM sounds the range of excitatory signal durations should predictably vary in a FM rate-tuned cell. Preliminary data indicate that our stimulus paradigm can disambiguate whether the evoked responses of an IC neuron are FM sweep rate tuned or FM duration tuned.

Nonlinearity of bituminous mixtures

NASA Astrophysics Data System (ADS)

Mangiafico, S.; Babadopulos, L. F. A. L.; Sauzéat, C.; Di Benedetto, H.

2018-02-01

This paper presents an experimental characterization of the strain dependency of the complex modulus of bituminous mixtures for strain amplitude levels lower than about 110 μm/m. A series of strain amplitude sweep tests are performed at different temperatures (8, 10, 12 and 14°C) and frequencies (0.3, 1, 3 and 10 Hz), during which complex modulus is monitored. For each combination of temperature and frequency, four maximum strain amplitudes are targeted (50, 75, 100 and 110 μm/m). For each of them, two series of 50 loading cycles are applied, respectively at decreasing and increasing strain amplitudes. Before each decreasing strain sweep and after each increasing strain sweep, 5 cycles are performed at constant maximum targeted strain amplitude. Experimental results show that the behavior of the studied material is strain dependent. The norm of the complex modulus decreases and phase angle increases with strain amplitude. Results are presented in Black and Cole-Cole plots, where characteristic directions of nonlinearity can be identified. Both the effects of nonlinearity in terms of the complex modulus variation and of the direction of nonlinearity in Black space seem to validate the time-temperature superposition principle with the same shift factors as for linear viscoelasticity. The comparison between results obtained during increasing and decreasing strain sweeps suggests the existence of another phenomenon occurring during cyclic loading, which appears to systematically induce a decrease of the norm of the complex modulus and an increase of the phase angle, regardless of the type of the strain sweep (increasing or decreasing).

How does the connectivity of open-framework conglomerates within multi-scale hierarchical fluvial architecture affect oil-sweep efficiency in waterflooding?

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

Gershenzon, Naum I.; Soltanian, Mohamad Reza; Ritzi, Robert W.

Understanding multi-phase fluid flow and transport processes within aquifers, candidate reservoirs for CO 2 sequestration, and petroleum reservoirs requires understanding a diverse set of geologic properties of the aquifer or reservoir, over a wide range of spatial and temporal scales. We focus on multiphase flow dynamics with wetting (e.g., water) and non-wetting (e.g., gas or oil) fluids, with one invading another. This problem is of general interest in a number of fields and is illustrated here by considering the sweep efficiency of oil during a waterflood. Using a relatively fine-resolution grid throughout a relatively large domain in these simulations andmore » probing the results with advanced scientific visualization tools (Reservoir Visualization Analysis [RVA]/ ParaView software) promote a better understanding of how smaller-scale features affect the aggregate behavior at larger scales. We studied the effects on oil-sweep efficiency of the proportion, hierarchical organization, and connectivity of high-permeability open-framework conglomerate (OFC) cross-sets within the multi-scale stratal architecture found in fluvial deposits. We further analyzed oil production rate, water breakthrough time, and spatial and temporal distribution of residual oil saturation. As expected, the effective permeability of the reservoir exhibits large-scale anisotropy created by the organization of OFC cross-sets within unit bars, and the organization of unit bars within compound- bars. As a result, oil-sweep efficiency critically depends on the direction of the pressure gradient. However, contrary to expectations, the total amount of trapped oil due to the effect of capillary trapping does not depend on the magnitude of the pressure gradient within the examined range. Hence the pressure difference between production and injection wells does not affect sweep efficiency; although the spatial distribution of oil remaining in the reservoir depends on this value. Whether or not clusters of connected OFC span the domain affects only the absolute rate of oil production—not sweep efficiency.« less

How does the connectivity of open-framework conglomerates within multi-scale hierarchical fluvial architecture affect oil-sweep efficiency in waterflooding?

DOE PAGES

Gershenzon, Naum I.; Soltanian, Mohamad Reza; Ritzi, Robert W.; ...

2015-10-23

Understanding multi-phase fluid flow and transport processes within aquifers, candidate reservoirs for CO 2 sequestration, and petroleum reservoirs requires understanding a diverse set of geologic properties of the aquifer or reservoir, over a wide range of spatial and temporal scales. We focus on multiphase flow dynamics with wetting (e.g., water) and non-wetting (e.g., gas or oil) fluids, with one invading another. This problem is of general interest in a number of fields and is illustrated here by considering the sweep efficiency of oil during a waterflood. Using a relatively fine-resolution grid throughout a relatively large domain in these simulations andmore » probing the results with advanced scientific visualization tools (Reservoir Visualization Analysis [RVA]/ ParaView software) promote a better understanding of how smaller-scale features affect the aggregate behavior at larger scales. We studied the effects on oil-sweep efficiency of the proportion, hierarchical organization, and connectivity of high-permeability open-framework conglomerate (OFC) cross-sets within the multi-scale stratal architecture found in fluvial deposits. We further analyzed oil production rate, water breakthrough time, and spatial and temporal distribution of residual oil saturation. As expected, the effective permeability of the reservoir exhibits large-scale anisotropy created by the organization of OFC cross-sets within unit bars, and the organization of unit bars within compound- bars. As a result, oil-sweep efficiency critically depends on the direction of the pressure gradient. However, contrary to expectations, the total amount of trapped oil due to the effect of capillary trapping does not depend on the magnitude of the pressure gradient within the examined range. Hence the pressure difference between production and injection wells does not affect sweep efficiency; although the spatial distribution of oil remaining in the reservoir depends on this value. Whether or not clusters of connected OFC span the domain affects only the absolute rate of oil production—not sweep efficiency.« less

Rapid selective sweep of pre-existing polymorphisms and slow fixation of new mutations in experimental evolution of Desulfovibrio vulgaris

DOE PAGES

Zhou, Aifen; Hillesland, Kristina L.; He, Zhili; ...

2015-04-07

To investigate the genetic basis of microbial evolutionary adaptation to salt (NaCl) stress, populations of Desulfovibrio vulgaris Hildenborough (DvH), a sulfate-reducing bacterium important for the biogeochemical cycling of sulfur, carbon and nitrogen, and potentially the bioremediation of toxic heavy metals and radionuclides, were propagated under salt stress or non-stress conditions for 1200 generations. Whole-genome sequencing revealed 11 mutations in salt stress-evolved clone ES9-11 and 14 mutations in non-stress-evolved clone EC3-10. Whole-population sequencing data suggested the rapid selective sweep of the pre-existing polymorphisms under salt stress within the first 100 generations and the slow fixation of new mutations. Population genotyping datamore » demonstrated that the rapid selective sweep of pre-existing polymorphisms was common in salt stress-evolved populations. In contrast, the selection of pre-existing polymorphisms was largely random in EC populations. Consistently, at 100 generations, stress-evolved population ES9 showed improved salt tolerance, namely increased growth rate (2.0-fold), higher biomass yield (1.8-fold) and shorter lag phase (0.7-fold) under higher salinity conditions. The beneficial nature of several mutations was confirmed by site-directed mutagenesis. All four tested mutations contributed to the shortened lag phases under higher salinity condition. In particular, compared with the salt tolerance improvement in ES9-11, a mutation in a histidine kinase protein gene lytS contributed 27% of the growth rate increase and 23% of the biomass yield increase while a mutation in hypothetical gene DVU2472 contributed 24% of the biomass yield increase. In conclusion, our results suggested that a few beneficial mutations could lead to dramatic improvements in salt tolerance.« less

A novel optical imaging system for investigating sarcomere dynamics in single skeletal muscle fibers

NASA Astrophysics Data System (ADS)

Panchangam, Appaji; Witte, Russell S.; Claflin, Dennis R.; O'Donnell, Matthew; Faulkner, John A.

2006-02-01

The protein substructure of skeletal muscle fibers forms a diffraction grating with repeating units, termed 'sarcomeres'. A laser scanning system is described that maps the lengths of sarcomeres (SL) and the widths of the first-order diffraction lines (DLW) of permeabilized single fibers in real-time. The apparatus translates a laser beam (λ = 670 nm and w 0 = ~75 μm) along the length of a fiber segment through 20 contiguous regions per sweep at 500 sweeps/s. The fiber segments (~1 mm long) were obtained from vastus lateralis muscles of humans by needle biopsy. During both passive stretches and maximum fixed-end activations, the mappings of SL and DLW of the fibers were extracted from the diffraction spectra. Heterogeneity of SLs was evaluated by computing the standard deviation ( σ SL) of the 20 SLs measured during a single sweep. Compared with the σ SL before a passive stretch, the increase of 5+/-0.5% in σ SL after the passive stretch, indicated differences in passive length-tension relationships along the fiber. In contrast, no change, ~0.5+/-0.1%, was observed in DLW. Within 10s after the fiber was returned to its initial length, the shape of the SL profile returned close to pre-stretch conditions ( σ SL = 1+/- 0.2%). Following maximum Ca 2+ - activation of the fiber, the heterogeneity of the steady state SLs increased greatly (DLW up by ~300% and σ SL up by ~100%). The scanning system provided high resolution tracking of sarcomere behavior single muscle fibers. Potential applications are for studies of the mechanisms of muscle fiber injury and injury propagation.

Rapid selective sweep of pre-existing polymorphisms and slow fixation of new mutations in experimental evolution of Desulfovibrio vulgaris

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

Zhou, Aifen; Hillesland, Kristina L.; He, Zhili

To investigate the genetic basis of microbial evolutionary adaptation to salt (NaCl) stress, populations of Desulfovibrio vulgaris Hildenborough (DvH), a sulfate-reducing bacterium important for the biogeochemical cycling of sulfur, carbon and nitrogen, and potentially the bioremediation of toxic heavy metals and radionuclides, were propagated under salt stress or non-stress conditions for 1200 generations. Whole-genome sequencing revealed 11 mutations in salt stress-evolved clone ES9-11 and 14 mutations in non-stress-evolved clone EC3-10. Whole-population sequencing data suggested the rapid selective sweep of the pre-existing polymorphisms under salt stress within the first 100 generations and the slow fixation of new mutations. Population genotyping datamore » demonstrated that the rapid selective sweep of pre-existing polymorphisms was common in salt stress-evolved populations. In contrast, the selection of pre-existing polymorphisms was largely random in EC populations. Consistently, at 100 generations, stress-evolved population ES9 showed improved salt tolerance, namely increased growth rate (2.0-fold), higher biomass yield (1.8-fold) and shorter lag phase (0.7-fold) under higher salinity conditions. The beneficial nature of several mutations was confirmed by site-directed mutagenesis. All four tested mutations contributed to the shortened lag phases under higher salinity condition. In particular, compared with the salt tolerance improvement in ES9-11, a mutation in a histidine kinase protein gene lytS contributed 27% of the growth rate increase and 23% of the biomass yield increase while a mutation in hypothetical gene DVU2472 contributed 24% of the biomass yield increase. In conclusion, our results suggested that a few beneficial mutations could lead to dramatic improvements in salt tolerance.« less

Rapid selective sweep of pre-existing polymorphisms and slow fixation of new mutations in experimental evolution of Desulfovibrio vulgaris

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

Zhou, Aifen; Hillesland, Kristina L.; He, Zhili

To investigate the genetic basis of microbial evolutionary adaptation to salt (NaCl) stress, populations of Desulfovibrio vulgaris Hildenborough (DvH), a sulfate-reducing bacterium important for the biogeochemical cycling of sulfur, carbon and nitrogen, and potentially the bioremediation of toxic heavy metals and radionuclides, were propagated under salt stress or non-stress conditions for 1200 generations. Whole-genome sequencing revealed 11 mutations in salt stress-evolved clone ES9-11 and 14 mutations in non-stress-evolved clone EC3-10. Whole-population sequencing data suggested the rapid selective sweep of the pre-existing polymorphisms under salt stress within the first 100 generations and the slow fixation of new mutations. Population genotyping datamore » demonstrated that the rapid selective sweep of pre-existing polymorphisms was common in salt stress-evolved populations. In contrast, the selection of pre-existing polymorphisms was largely random in EC populations. Consistently, at 100 generations, stress-evolved population ES9 showed improved salt tolerance, namely increased growth rate (2.0-fold), higher biomass yield (1.8-fold) and shorter lag phase (0.7-fold) under higher salinity conditions. The beneficial nature of several mutations was confirmed by site-directed mutagenesis. All four tested mutations contributed to the shortened lag phases under higher salinity condition. In particular, compared with the salt tolerance improvement in ES9-11, a mutation in a histidine kinase protein gene lytS contributed 27% of the growth rate increase and 23% of the biomass yield increase while a mutation in hypothetical gene DVU2472 contributed 24% of the biomass yield increase. Our results suggested that a few beneficial mutations could lead to dramatic improvements in salt tolerance.« less

Rapid selective sweep of pre-existing polymorphisms and slow fixation of new mutations in experimental evolution of Desulfovibrio vulgaris.

PubMed

Zhou, Aifen; Hillesland, Kristina L; He, Zhili; Schackwitz, Wendy; Tu, Qichao; Zane, Grant M; Ma, Qiao; Qu, Yuanyuan; Stahl, David A; Wall, Judy D; Hazen, Terry C; Fields, Matthew W; Arkin, Adam P; Zhou, Jizhong

2015-11-01

To investigate the genetic basis of microbial evolutionary adaptation to salt (NaCl) stress, populations of Desulfovibrio vulgaris Hildenborough (DvH), a sulfate-reducing bacterium important for the biogeochemical cycling of sulfur, carbon and nitrogen, and potentially the bioremediation of toxic heavy metals and radionuclides, were propagated under salt stress or non-stress conditions for 1200 generations. Whole-genome sequencing revealed 11 mutations in salt stress-evolved clone ES9-11 and 14 mutations in non-stress-evolved clone EC3-10. Whole-population sequencing data suggested the rapid selective sweep of the pre-existing polymorphisms under salt stress within the first 100 generations and the slow fixation of new mutations. Population genotyping data demonstrated that the rapid selective sweep of pre-existing polymorphisms was common in salt stress-evolved populations. In contrast, the selection of pre-existing polymorphisms was largely random in EC populations. Consistently, at 100 generations, stress-evolved population ES9 showed improved salt tolerance, namely increased growth rate (2.0-fold), higher biomass yield (1.8-fold) and shorter lag phase (0.7-fold) under higher salinity conditions. The beneficial nature of several mutations was confirmed by site-directed mutagenesis. All four tested mutations contributed to the shortened lag phases under higher salinity condition. In particular, compared with the salt tolerance improvement in ES9-11, a mutation in a histidine kinase protein gene lytS contributed 27% of the growth rate increase and 23% of the biomass yield increase while a mutation in hypothetical gene DVU2472 contributed 24% of the biomass yield increase. Our results suggested that a few beneficial mutations could lead to dramatic improvements in salt tolerance.

Rapid selective sweep of pre-existing polymorphisms and slow fixation of new mutations in experimental evolution of Desulfovibrio vulgaris

PubMed Central

Zhou, Aifen; Hillesland, Kristina L; He, Zhili; Schackwitz, Wendy; Tu, Qichao; Zane, Grant M; Ma, Qiao; Qu, Yuanyuan; Stahl, David A; Wall, Judy D; Hazen, Terry C; Fields, Matthew W; Arkin, Adam P; Zhou, Jizhong

2015-01-01

To investigate the genetic basis of microbial evolutionary adaptation to salt (NaCl) stress, populations of Desulfovibrio vulgaris Hildenborough (DvH), a sulfate-reducing bacterium important for the biogeochemical cycling of sulfur, carbon and nitrogen, and potentially the bioremediation of toxic heavy metals and radionuclides, were propagated under salt stress or non-stress conditions for 1200 generations. Whole-genome sequencing revealed 11 mutations in salt stress-evolved clone ES9-11 and 14 mutations in non-stress-evolved clone EC3-10. Whole-population sequencing data suggested the rapid selective sweep of the pre-existing polymorphisms under salt stress within the first 100 generations and the slow fixation of new mutations. Population genotyping data demonstrated that the rapid selective sweep of pre-existing polymorphisms was common in salt stress-evolved populations. In contrast, the selection of pre-existing polymorphisms was largely random in EC populations. Consistently, at 100 generations, stress-evolved population ES9 showed improved salt tolerance, namely increased growth rate (2.0-fold), higher biomass yield (1.8-fold) and shorter lag phase (0.7-fold) under higher salinity conditions. The beneficial nature of several mutations was confirmed by site-directed mutagenesis. All four tested mutations contributed to the shortened lag phases under higher salinity condition. In particular, compared with the salt tolerance improvement in ES9-11, a mutation in a histidine kinase protein gene lytS contributed 27% of the growth rate increase and 23% of the biomass yield increase while a mutation in hypothetical gene DVU2472 contributed 24% of the biomass yield increase. Our results suggested that a few beneficial mutations could lead to dramatic improvements in salt tolerance. PMID:25848870

EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative.

PubMed

Lilliu, S; Maragliano, C; Hampton, M; Elliott, M; Stefancich, M; Chiesa, M; Dahlem, M S; Macdonald, J E

2013-11-27

We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications.

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.

Magnetic Enrichment of Dendritic Cell Vaccine in Lymph Node with Fluorescent-Magnetic Nanoparticles Enhanced Cancer Immunotherapy

PubMed Central

Jin, Honglin; Qian, Yuan; Dai, Yanfeng; Qiao, Sha; Huang, Chuan; Lu, Lisen; Luo, Qingming; Chen, Jing; Zhang, Zhihong

2016-01-01

Dendritic cell (DC) migration to the lymph node is a key component of DC-based immunotherapy. However, the DC homing rate to the lymphoid tissues is poor, thus hindering the DC-mediated activation of antigen-specific T cells. Here, we developed a system using fluorescent magnetic nanoparticles (α-AP-fmNPs; loaded with antigen peptide, iron oxide nanoparticles, and indocyanine green) in combination with magnetic pull force (MPF) to successfully manipulate DC migration in vitro and in vivo. α-AP-fmNPs endowed DCs with MPF-responsiveness, antigen presentation, and simultaneous optical and magnetic resonance imaging detectability. We showed for the first time that α-AP-fmNP-loaded DCs were sensitive to MPF, and their migration efficiency could be dramatically improved both in vitro and in vivo through MPF treatment. Due to the enhanced migration of DCs, MPF treatment significantly augmented antitumor efficacy of the nanoparticle-loaded DCs. Therefore, we have developed a biocompatible approach with which to improve the homing efficiency of DCs and subsequent anti-tumor efficacy, and track their migration by multi-modality imaging, with great potential applications for DC-based cancer immunotherapy. PMID:27698936

Anti-apoptosis Effect of Decoy Receptor 3 in Cholangiocarcinoma Cell Line TFK-1

PubMed Central

Xu, Ying-Chen; Cui, Jing; Zhang, Li-Jun; Zhang, Dong-Xin; Xing, Bing-Chen; Huang, Xiong-Wei-Ye; Wu, Ji-Xiang; Liang, Chao-Jie; Li, Guang-Ming

2018-01-01

Background: Decoy receptor 3 (DcR3) is a protein with anti-apoptotic effect that belongs to the tumor necrosis factor receptor superfamily. DcR3 is highly expressed in a variety of malignant tumors including cholangiocarcinoma and its expression was found to be related to the clinical stage, the invasion, and the metastasis of the tumor. This in vitro study aimed to investigate the effect of downregulated expression of DcR3 on cell viability, cell apoptosis, and cell cycle in cholangiocarcinoma cell line TFK-1. Methods: Three different cell lines were cultured: human cholangiocarcinoma TFK-1, human biliary epithelial carcinoma HuCCT-1, and human cholangiocarcinoma RBE. The cholangiocarcinoma cell line with the highest expression of DcR3 was selected for further investigation. The expression of DcR3 was silenced/knocked down by transfection with DcR3-siRNA in the selected cell line. Various biological phenotype parameters such as cell viability, apoptosis, and cell cycle were observed. Results: The mRNA and protein levels of DcR3 were measured in the three cell lines, and TFK-1 was selected. After the treatment with DcR3-siRNA for 48 h, DcR3 mRNA and protein expression in the treatment group were 38.45% (P < 0.01) and 48.03% (P < 0.05) of that of the control, respectively. It was found that the cell viability decreased to 61.87% of the control group (P < 0.01) after the downregulation of DcR3 in cholangiocarcinoma cell line TFK-1 by transfection with DcR3-siRNA, while the percentage of apoptotic cells was 2.98 times as compared with the control group (P < 0.05). Compared with the control group the ratio of G0/G1 increased, and the ratio of G2/M decreased in the treatment group. However, the differences were not statistically significant. Conclusions: The effect of DcR3 on the growth and apoptosis of cholangiocarcinoma has been demonstrated. DcR3 is not only a predictive marker for malignant tumor but it is also likely to be a potential target for cancer gene therapy. Further studies should focus on exploring the binding ligand of DcR3, the signaling pathway involved, and the molecular mechanism for the regulation of DcR3 expression in cholangiocarcinoma. PMID:29271385

Anti-apoptosis Effect of Decoy Receptor 3 in Cholangiocarcinoma Cell Line TFK-1.

PubMed

Xu, Ying-Chen; Cui, Jing; Zhang, Li-Jun; Zhang, Dong-Xin; Xing, Bing-Chen; Huang, Xiong-Wei-Ye; Wu, Ji-Xiang; Liang, Chao-Jie; Li, Guang-Ming

2018-01-05

Decoy receptor 3 (DcR3) is a protein with anti-apoptotic effect that belongs to the tumor necrosis factor receptor superfamily. DcR3 is highly expressed in a variety of malignant tumors including cholangiocarcinoma and its expression was found to be related to the clinical stage, the invasion, and the metastasis of the tumor. This in vitro study aimed to investigate the effect of downregulated expression of DcR3 on cell viability, cell apoptosis, and cell cycle in cholangiocarcinoma cell line TFK-1. Three different cell lines were cultured: human cholangiocarcinoma TFK-1, human biliary epithelial carcinoma HuCCT-1, and human cholangiocarcinoma RBE. The cholangiocarcinoma cell line with the highest expression of DcR3 was selected for further investigation. The expression of DcR3 was silenced/knocked down by transfection with DcR3-siRNA in the selected cell line. Various biological phenotype parameters such as cell viability, apoptosis, and cell cycle were observed. The mRNA and protein levels of DcR3 were measured in the three cell lines, and TFK-1 was selected. After the treatment with DcR3-siRNA for 48 h, DcR3 mRNA and protein expression in the treatment group were 38.45% (P < 0.01) and 48.03% (P < 0.05) of that of the control, respectively. It was found that the cell viability decreased to 61.87% of the control group (P < 0.01) after the downregulation of DcR3 in cholangiocarcinoma cell line TFK-1 by transfection with DcR3-siRNA, while the percentage of apoptotic cells was 2.98 times as compared with the control group (P < 0.05). Compared with the control group the ratio of G0/G1increased, and the ratio of G2/M decreased in the treatment group. However, the differences were not statistically significant. The effect of DcR3 on the growth and apoptosis of cholangiocarcinoma has been demonstrated. DcR3 is not only a predictive marker for malignant tumor but it is also likely to be a potential target for cancer gene therapy. Further studies should focus on exploring the binding ligand of DcR3, the signaling pathway involved, and the molecular mechanism for the regulation of DcR3 expression in cholangiocarcinoma.

Historical Material Analysis of DC745U Pressure Pads

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

Ortiz-Acosta, Denisse

As part of the Enhance Surveillance mission, it is the goal to provide suitable lifetime assessment of stockpile materials. This report is an accumulation of historical publication on the DC745U material and their findings. It is the intention that the B61 LEP program uses this collection of data to further develop their understanding and potential areas of study. DC745U is a commercially available silicone elastomer consisting of dimethyl, methyl-phenyl, and methyl-vinyl siloxane repeat units. Originally, this material was manufactured by Dow Corning as Silastic{reg_sign} DC745U at their manufacturing facility in Kendallville, IN. Recently, Dow Corning shifted this material to themore » Xiameter{reg_sign} brand product line. Currently, DC745U is available through Xiameter{reg_sign} or Dow Corning's distributor R. D. Abbott Company. DC745U is cured using 0.5 wt% vinyl-specific peroxide curing agent known as Luperox 101 or Varox DBPH-50. This silicone elastomer is used in numerous parts, including two major components (outer pressure pads and aft cap support) in the W80 and as pressure pads on the B61. DC745U is a proprietary formulation, thus Dow Corning provides limited information on its composition and properties. Based on past experience with Dow Corning, DC745U is at risk of formulation changes without notification to the costumer. A formulation change for DC745U may have a significant impact because the network structure is a key variable in determining material properties. The purpose of this report is to provide an overview of historical DC745U studies and identify gaps that need to be addressed in future work. Some of the previous studies include the following: 1. Spectroscopic characterization of raw gum stock. 2. Spectroscopic, thermal, and mechanical studies on cured DC745U. 3. Nuclear Magnetic Resonance (NMR) and solvent swelling studies on DC745U with different crosslink densities. 4. NMR, solvent swelling, thermal, and mechanical studies on thermally aged DC745U. 5. NMR, solvent swelling, thermal, and mechanical studies on radiolytically aged DC745U. Each area is reviewed and further work is suggested to improve our understanding of DC745U for systems engineering, surveillance, aging assessments, and lifetime assessment.« less

Human Milk Blocks DC-SIGN–Pathogen Interaction via MUC1

PubMed Central

Koning, Nathalie; Kessen, Sabine F. M.; Van Der Voorn, J. Patrick; Appelmelk, Ben J.; Jeurink, Prescilla V.; Knippels, Leon M. J.; Garssen, Johan; Van Kooyk, Yvette

2015-01-01

Beneficial effects of breastfeeding are well-recognized and include both immediate neonatal protection against pathogens and long-term protection against allergies and autoimmune diseases. Although several proteins have been identified to have anti-viral or anti-bacterial effects like secretory IgA or lactoferrin, the mechanisms of immune modulation are not fully understood. Recent studies identified important beneficial effects of glycans in human milk, such as those expressed in oligosaccharides or on glycoproteins. Glycans are recognized by the carbohydrate receptors C-type lectins on dendritic cell (DC) and specific tissue macrophages, which exert important functions in immune modulation and immune homeostasis. A well-characterized C-type lectin is dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), which binds terminal fucose. The present study shows that in human milk, MUC1 is the major milk glycoprotein that binds to the lectin domain of DC-SIGN and prevents pathogen interaction through the presence of Lewis x-type oligosaccharides. Surprisingly, this was specific for human milk, as formula, bovine or camel milk did not show any presence of proteins that interacted with DC-SIGN. The expression of DC-SIGN is found in young infants along the entire gastrointestinal tract. Our data thus suggest the importance of human milk glycoproteins for blocking pathogen interaction to DC in young children. Moreover, a potential benefit of human milk later in life in shaping the infants immune system through DC-SIGN cannot be ruled out. PMID:25821450

Specific Dioscorea Phytoextracts Enhance Potency of TCL-Loaded DC-Based Cancer Vaccines

PubMed Central

Chang, Wei-Ting; Chen, Hui-Ming; Yin, Shu-Yi; Chen, Yung-Hsiang; Wen, Chih-Chun; Wei, Wen-Chi; Lai, Phoency; Wang, Cheng-Hsin; Yang, Ning-Sun

2013-01-01

Dioscorea tuber phytoextracts can confer immunomodulatory activities ex vivo and improve regeneration of bone marrow cells in vivo. In present study, we evaluated specific Dioscorea phytoextracts for use ex vivo as a bone-marrow-derived dendritic cell- (DC-) based vaccine adjuvant for cancer immunotherapy. Fractionated Dioscorea extracts (DsII) were assayed for their effect on maturation and functions of DC ex vivo and antimelanoma activity of DC-based vaccine in vivo. The phytoextract from 50–75% ethanol-precipitated fraction of Dioscorea alata var. purpurea Tainung no. 5 tuber, designated as DsII-TN5, showed a strong augmentation of tumor cell lysate- (TCL-) loaded DC-mediated activation of T-cell proliferation. DsII-TN5 stimulated the expression of CD40, CD80, CD86, and IL-1β in TCL-loaded DCs and downregulated the expression of TGF-β1. DC vaccines prepared by a specific schema (TCL (2 h) + LPS (22 h)) showed the strongest antitumor activity. DsII-TN5 as a DC vaccine adjuvant showed strong antimelanoma activity and reduced myeloid-derived suppressor cell (MDSC) population in tested mice. DsII-TN5 can also activate DCs to enhance Th1- and Th17-related cytokine expressions. Biochemical analysis showed that DsII-TN5 consists mainly of polysaccharides containing a high level (53%) of mannose residues. We suggest that DsII-TN5 may have potential for future application as a potent, cost-effective adjuvant for DC-based cancer vaccines. PMID:23935688

Knockdown of Decoy Receptor 3 Impairs Growth and Invasiveness of Hepatocellular Carcinoma Cell Line of HepG2.

PubMed

Zhou, Xiao-Na; Li, Guang-Ming; Xu, Ying-Chen; Zhao, Tuan-Jie; Wu, Ji-Xiang

2016-11-05

Decoy receptor 3 (DcR3) binds to Fas ligand (FasL) and inhibits FasL-induced apoptosis. The receptor is overexpressed in hepatocellular carcinoma (HCC), and it is associated with the growth and metastatic spread of tumors. DcR3 holds promises as a new target for the treatment of HCC, but little is known regarding the molecular mechanisms underlying the oncogenic properties of DcR3. The present work, therefore, examined the role of DcR3 in regulating the growth and invasive property of liver cancer cell HepG2. HepG2 cells were stably transfected with lentivirus-based short hairpin RNA vector targeting DcR3. After the knockdown of DcR3 was confirmed, cell proliferation, clone formation, ability of migrating across transwell membrane, and wound healing were assessed in vitro. Matrix metalloproteinase-9 (MMP 9) and vascular epithelial growth factor (VEGF)-C and D expressions of the DcR3 knockdown were also studied. Comparisons between multiple groups were done using one-way analysis of variance (ANOVA), while pairwise comparisons were performed using Student's t test. P< 0.05 was regarded statistically significant. DcR3 was overexpressed in HepG2 compared to other HCC cell lines and normal hepatocyte Lo-2. Stable knockdown of DcR3 slowed down the growth of HepG2 (P < 0.05) and reduced the number of clones formed by 50% compared to those without DcR3 knockdown (P < 0.05). The knockdown also reduced the migration of HepG2 across transwell matrix membrane by five folds compared to the control (P < 0.05) and suppressed the closure of scratch wound (P < 0.05). In addition, the messenger RNA levels of MMP 9, VEGF-C, and VEGF-D were significantly suppressed by DcR3 knockdown by 90% when compared with the mock control (P < 0.05). Loss of DcR3 impaired the growth and invasive property of HCC cell line of HepG2. Targeting DcR3 may be a potential therapeutic approach for the treatment of HCC.

Knockdown of Decoy Receptor 3 Impairs Growth and Invasiveness of Hepatocellular Carcinoma Cell Line of HepG2

PubMed Central

Zhou, Xiao-Na; Li, Guang-Ming; Xu, Ying-Chen; Zhao, Tuan-Jie; Wu, Ji-Xiang

2016-01-01

Background: Decoy receptor 3 (DcR3) binds to Fas ligand (FasL) and inhibits FasL-induced apoptosis. The receptor is overexpressed in hepatocellular carcinoma (HCC), and it is associated with the growth and metastatic spread of tumors. DcR3 holds promises as a new target for the treatment of HCC, but little is known regarding the molecular mechanisms underlying the oncogenic properties of DcR3. The present work, therefore, examined the role of DcR3 in regulating the growth and invasive property of liver cancer cell HepG2. Methods: HepG2 cells were stably transfected with lentivirus-based short hairpin RNA vector targeting DcR3. After the knockdown of DcR3 was confirmed, cell proliferation, clone formation, ability of migrating across transwell membrane, and wound healing were assessed in vitro. Matrix metalloproteinase-9 (MMP 9) and vascular epithelial growth factor (VEGF)-C and D expressions of the DcR3 knockdown were also studied. Comparisons between multiple groups were done using one-way analysis of variance (ANOVA), while pairwise comparisons were performed using Student's t test. P < 0.05 was regarded statistically significant. Results: DcR3 was overexpressed in HepG2 compared to other HCC cell lines and normal hepatocyte Lo-2. Stable knockdown of DcR3 slowed down the growth of HepG2 (P < 0.05) and reduced the number of clones formed by 50% compared to those without DcR3 knockdown (P < 0.05). The knockdown also reduced the migration of HepG2 across transwell matrix membrane by five folds compared to the control (P < 0.05) and suppressed the closure of scratch wound (P < 0.05). In addition, the messenger RNA levels of MMP 9, VEGF-C, and VEGF-D were significantly suppressed by DcR3 knockdown by 90% when compared with the mock control (P < 0.05). Conclusions: Loss of DcR3 impaired the growth and invasive property of HCC cell line of HepG2. Targeting DcR3 may be a potential therapeutic approach for the treatment of HCC. PMID:27779171

Sweet resin bush on the Santa Rita Experimental Range: An eradication effort

Treesearch

Larry D. Howery; Bruce D. Munda; Dan G. Robinett; Harry H. Buck

2003-01-01

Sweet resin bush (Euryops subcarnosus DC ssp. vulgaris B. Nord; or, Euryops multifidis (L. f.) DC.), a South African shrub introduced to Arizona in the 1930s, was discovered on the Santa Rita Experimental Range (SRER) in 1998. Due to the threat of spread of this invasive plant and its potential to cause adverse environmental and economic effects, and because it posed a...