There is no clam with coats in the calm coast: delimiting the transposed-letter priming effect.

PubMed

Duñabeitia, Jon Andoni; Perea, Manuel; Carreiras, Manuel

2009-10-01

In this article, we explore the transposed-letter priming effect (e.g., jugde-JUDGE vs. jupte-JUDGE), a phenomenon that taps into some key issues on how the brain encodes letter positions and has favoured the creation of new input coding schemes. However, almost all the empirical evidence from transposed-letter priming experiments comes from nonword primes (e.g., jugde-JUDGE). Indeed, previous evidence when using word-word pairs (e.g., causal-CASUAL) is not conclusive. Here, we conducted five masked priming lexical decision experiments that examined the relationship between pairs of real words that differed only in the transposition of two of their letters (e.g., CASUAL vs. CAUSAL). Results showed that, unlike transposed-letter nonwords, transposed-letter words do not seem to affect the identification time of their transposed-letter mates. Thus, prime lexicality is a key factor that modulates the magnitude of transposed-letter priming effects. These results are interpreted under the assumption of the existence of lateral inhibition processes occurring within the lexical level-which cancels out any orthographic facilitation due to the overlapping letters. We examine the implications of these findings for models of visual-word recognition.

Orthographic Reading Deficits in Dyslexic Japanese Children: Examining the Transposed-Letter Effect in the Color-Word Stroop Paradigm

PubMed Central

Ogawa, Shino; Shibasaki, Masahiro; Isomura, Tomoko; Masataka, Nobuo

2016-01-01

In orthographic reading, the transposed-letter effect (TLE) is the perception of a transposed-letter position word such as “cholocate” as the correct word “chocolate.” Although previous studies on dyslexic children using alphabetic languages have reported such orthographic reading deficits, the extent of orthographic reading impairment in dyslexic Japanese children has remained unknown. This study examined the TLE in dyslexic Japanese children using the color-word Stroop paradigm comprising congruent and incongruent Japanese hiragana words with correct and transposed-letter positions. We found that typically developed children exhibited Stroop effects in Japanese hiragana words with both correct and transposed-letter positions, thus indicating the presence of TLE. In contrast, dyslexic children indicated Stroop effects in correct letter positions in Japanese words but not in transposed, which indicated an absence of the TLE. These results suggest that dyslexic Japanese children, similar to dyslexic children using alphabetic languages, may also have a problem with orthographic reading. PMID:27303331

Orthographic Reading Deficits in Dyslexic Japanese Children: Examining the Transposed-Letter Effect in the Color-Word Stroop Paradigm.

PubMed

Ogawa, Shino; Shibasaki, Masahiro; Isomura, Tomoko; Masataka, Nobuo

2016-01-01

In orthographic reading, the transposed-letter effect (TLE) is the perception of a transposed-letter position word such as "cholocate" as the correct word "chocolate." Although previous studies on dyslexic children using alphabetic languages have reported such orthographic reading deficits, the extent of orthographic reading impairment in dyslexic Japanese children has remained unknown. This study examined the TLE in dyslexic Japanese children using the color-word Stroop paradigm comprising congruent and incongruent Japanese hiragana words with correct and transposed-letter positions. We found that typically developed children exhibited Stroop effects in Japanese hiragana words with both correct and transposed-letter positions, thus indicating the presence of TLE. In contrast, dyslexic children indicated Stroop effects in correct letter positions in Japanese words but not in transposed, which indicated an absence of the TLE. These results suggest that dyslexic Japanese children, similar to dyslexic children using alphabetic languages, may also have a problem with orthographic reading.

Pressure, temperature and density drops along supercritical fluid chromatography columns in different thermal environments. III. Mixtures of carbon dioxide and methanol as the mobile phase.

PubMed

Poe, Donald P; Veit, Devon; Ranger, Megan; Kaczmarski, Krzysztof; Tarafder, Abhijit; Guiochon, Georges

2014-01-03

The pressure, temperature and density drops along SFC columns eluted with a CO2/methanol mobile phase were measured and compared with theoretical values. For columns packed with 3- and 5-μm particles the pressure and temperature drops were measured using a mobile phase of 95% CO2 and 5% methanol at a flow rate of 5mL/min, at temperatures from 20 to 100°C, and outlet pressures from 80 to 300bar. The density drop was calculated based on the temperature and pressure at the column inlet and outlet. The columns were suspended in a circulating air bath, either bare or covered with foam insulation. The experimental measurements were compared to theoretical results obtained by numerical simulation. For the convective air condition at outlet pressures above 100bar the average difference between the experimental and calculated temperature drops and pressure drops were 0.1°C and 0.7% for the bare 3-μm column, respectively, and were 0.6°C and 4.1% for the insulated column. The observed temperature drops for the insulated columns are consistent with those predicted by the Joule-Thomson coefficients for isenthalpic expansion. The dependence of the temperature and the pressure drops on the Joule-Thomson coefficient and kinematic viscosity are described for carbon dioxide mobile phases containing up to 20% methanol. Copyright © 2013 Elsevier B.V. All rights reserved.

Numerical Investigation of Temperature Distribution in an Eroded Bend Pipe and Prediction of Erosion Reduced Thickness

PubMed Central

Zhu, Hongjun; Feng, Guang; Wang, Qijun

2014-01-01

Accurate prediction of erosion thickness is essential for pipe engineering. The objective of the present paper is to study the temperature distribution in an eroded bend pipe and find a new method to predict the erosion reduced thickness. Computational fluid dynamic (CFD) simulations with FLUENT software are carried out to investigate the temperature field. And effects of oil inlet rate, oil inlet temperature, and erosion reduced thickness are examined. The presence of erosion pit brings about the obvious fluctuation of temperature drop along the extrados of bend. And the minimum temperature drop presents at the most severe erosion point. Small inlet temperature or large inlet velocity can lead to small temperature drop, while shallow erosion pit causes great temperature drop. The dimensionless minimum temperature drop is analyzed and the fitting formula is obtained. Using the formula we can calculate the erosion reduced thickness, which is only needed to monitor the outer surface temperature of bend pipe. This new method can provide useful guidance for pipeline monitoring and replacement. PMID:24719576

Non-contact temperature measurement of a falling drop

NASA Technical Reports Server (NTRS)

Hofmeister, William; Bayuzick, R. J.; Robinson, M. B.

1989-01-01

The 105 meter drop tube at NASA-Marshall has been used in a number of experiments to determine the effects of containerless, microgravity processing on the undercooling and solidification behavior of metals and alloys. These experiments have been limited, however, because direct temperature measurement of the falling drops has not been available. Undercooling and nucleation temperatures are calculated from thermophysical properties based on droplet cooling models. In most cases these properties are not well known, particularly in the undercooled state. This results in a large amount of uncertainty in the determination of nucleation temperatures. If temperature measurement can be accomplished then the thermal history of the drops could be well documented. This would lead to a better understanding of the thermophysical and thermal radiative properties of undercooled melts. An effort to measure the temperature of a falling drop is under way. The technique uses two color pyrometry and high speed data acquisition. The approach is presented along with some preliminary data from drop tube experiments. The results from droplet cooling models is compared with noncontact temperature measurements.

Surface temperature measurements of a levitated water drop during laser irradiation

NASA Astrophysics Data System (ADS)

Brownell, Cody; Tracey, Timothy

2016-11-01

Simulation of high energy laser propagation and scattering in the maritime environment is problematic, due to the high liklihood of turbulence, fog, and rain or sea spray within the beam path. Laser interactions with large water drops (diameters of approximately 1-mm), such as those found in a light rain, have received relatively less attention. In this regime a high energy laser will rapidly heat and vaporize a water drop as it traverses the beam path, but the exact heating / vaporization rate, its dependence on impurities, and ancillary effects on the drop or surroundings are unclear. In this work we present surface temperature measurements of a water drop obtained using a FLIR IR camera. The drop is acoustically levitated, and subject to a continuous wave laser with a wavelength of 1070-nm and a mean irradiance of approximately 500 W/cm2. These measurements show that the steady-state surface temperature of the drop is well below the saturation temperature, yet based on the time history of the drop volume vaporization begins almost immediately upon laser strike. Inferences on the turbulence characteristics within the drop are also made from measurements of the fluctuations in the surface temperature. Supported by ONR, HEL-JTO, and USNA Trident Scholar Program.

Transposed-Letter and Laterality Effects in Lexical Decision

ERIC Educational Resources Information Center

Perea, Manuel; Fraga, Isabel

2006-01-01

Two divided visual field lexical decision experiments were conducted to examine the role of the cerebral hemispheres in transposed-letter similarity effects. In Experiment 1, we created two types of nonwords: nonadjacent transposed-letter nonwords ("TRADEGIA"; the base word was "TRAGEDIA," the Spanish for "TRAGEDY") and two-letter different…

Measures of extents of laterality for high-frequency ``transposed'' stimuli under conditions of binaural interference

NASA Astrophysics Data System (ADS)

Bernstein, Leslie R.; Trahiotis, Constantine

2005-09-01

Our purpose in this study was to determine whether across-frequency binaural interference would occur if ITD-based extents of laterality were measured using high-frequency transposed stimuli as targets. The results of an earlier study [L. R. Bernstein and C. Trahiotis, J. Acoust. Soc. Am. 116, 3062-3069 (2004)], which focused on threshold-ITDs, rather than extents of laterality, suggested that high-frequency transposed stimuli might be ``immune'' to binaural interference effects resulting from the addition of a spectrally remote, low-frequency interferer. In contrast to the earlier findings, the data from this study indicate that high-frequency transposed targets are susceptible to binaural interference. Nevertheless, high-frequency transposed targets, even when presented along with an interferer, yielded greater extents of ITD-based laterality than did high-frequency Gaussian noise targets presented in isolation. That is, the ``enhanced potency'' of ITDs conveyed by transposed stimuli persisted, even in the presence of a low-frequency interferer. Predictions made using an extension of the model of Heller and Trahiotis [L. M. Heller and C. Trahiotis, J. Acoust. Soc. Am. 99, 3632-3637 (1996)] accounted well for across-frequency binaural interference obtained with conventional Gaussian noise targets but, in all but one case, overpredicted the amounts of interference found with the transposed targets.

Microwave Dielectric Heating of Drops in Microfluidic Devices†

PubMed Central

Issadore, David; Humphry, Katherine J.; Brown, Keith A.; Sandberg, Lori; Weitz, David; Westervelt, Robert M.

2010-01-01

We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally isolated picoliter drop of water and this enables very fast thermal cycling. We demonstrate microwave dielectric heating in a microfluidic device that integrates a flow-focusing drop maker, drop splitters, and metal electrodes to locally deliver microwave power from an inexpensive, commercially available 3.0 GHz source and amplifier. The temperature of the drops is measured by observing the temperature dependent fluorescence intensity of cadmium selenide nanocrystals suspended in the water drops. We demonstrate characteristic heating times as short as 15 ms to steady-state temperatures as large as 30°C above the base temperature of the microfluidic device. Many common biological and chemical applications require rapid and local control of temperature, such as PCR amplification of DNA, and can benefit from this new technique. PMID:19495453

Identification of miniature inverted-repeat transposable elements (MITEs) and biogenesis of their siRNAs in the Solanaceae: New functional implications for MITEs

USDA-ARS?s Scientific Manuscript database

Small RNAs regulate the genome by guiding transcriptional and post-transcriptional silencing machinery to specific target sequences, including genes and transposable elements (TEs). Although miniature inverted-repeat transposable elements (MITEs) are closely associated with euchromatic genes, the br...

Can "CANISO" Activate "CASINO"? Transposed-Letter Similarity Effects with Nonadjacent Letter Positions

ERIC Educational Resources Information Center

Perea, Manuel; Lupker, Stephen J.

2004-01-01

Nonwords created by transposing two "adjacent" letters (i.e., transposed-letter (TL) nonwords like "jugde") are very effective at activating the lexical representation of their base words. This fact poses problems for most computational models of word recognition (e.g., the interactive-activation model and its extensions), which assume that exact…

TRANSPOSABLE REGULARIZED COVARIANCE MODELS WITH AN APPLICATION TO MISSING DATA IMPUTATION

PubMed Central

Allen, Genevera I.; Tibshirani, Robert

2015-01-01

Missing data estimation is an important challenge with high-dimensional data arranged in the form of a matrix. Typically this data matrix is transposable, meaning that either the rows, columns or both can be treated as features. To model transposable data, we present a modification of the matrix-variate normal, the mean-restricted matrix-variate normal, in which the rows and columns each have a separate mean vector and covariance matrix. By placing additive penalties on the inverse covariance matrices of the rows and columns, these so called transposable regularized covariance models allow for maximum likelihood estimation of the mean and non-singular covariance matrices. Using these models, we formulate EM-type algorithms for missing data imputation in both the multivariate and transposable frameworks. We present theoretical results exploiting the structure of our transposable models that allow these models and imputation methods to be applied to high-dimensional data. Simulations and results on microarray data and the Netflix data show that these imputation techniques often outperform existing methods and offer a greater degree of flexibility. PMID:26877823

TRANSPOSABLE REGULARIZED COVARIANCE MODELS WITH AN APPLICATION TO MISSING DATA IMPUTATION.

PubMed

Allen, Genevera I; Tibshirani, Robert

2010-06-01

Missing data estimation is an important challenge with high-dimensional data arranged in the form of a matrix. Typically this data matrix is transposable , meaning that either the rows, columns or both can be treated as features. To model transposable data, we present a modification of the matrix-variate normal, the mean-restricted matrix-variate normal , in which the rows and columns each have a separate mean vector and covariance matrix. By placing additive penalties on the inverse covariance matrices of the rows and columns, these so called transposable regularized covariance models allow for maximum likelihood estimation of the mean and non-singular covariance matrices. Using these models, we formulate EM-type algorithms for missing data imputation in both the multivariate and transposable frameworks. We present theoretical results exploiting the structure of our transposable models that allow these models and imputation methods to be applied to high-dimensional data. Simulations and results on microarray data and the Netflix data show that these imputation techniques often outperform existing methods and offer a greater degree of flexibility.

Dynamical mean-field theory, density-matrix embedding theory, and rotationally invariant slave bosons: A unified perspective

DOE PAGES

Ayral, Thomas; Lee, Tsung-Han; Kotliar, Gabriel

2017-12-26

In this paper, we present a unified perspective on dynamical mean-field theory (DMFT), density-matrix embedding theory (DMET), and rotationally invariant slave bosons (RISB). We show that DMET can be regarded as a simplification of the RISB method where the quasiparticle weight is set to unity. Finally, this relation makes it easy to transpose extensions of a given method to another: For instance, a temperature-dependent version of RISB can be used to derive a temperature-dependent free-energy formula for DMET.

Dynamical mean-field theory, density-matrix embedding theory, and rotationally invariant slave bosons: A unified perspective

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

Ayral, Thomas; Lee, Tsung-Han; Kotliar, Gabriel

In this paper, we present a unified perspective on dynamical mean-field theory (DMFT), density-matrix embedding theory (DMET), and rotationally invariant slave bosons (RISB). We show that DMET can be regarded as a simplification of the RISB method where the quasiparticle weight is set to unity. Finally, this relation makes it easy to transpose extensions of a given method to another: For instance, a temperature-dependent version of RISB can be used to derive a temperature-dependent free-energy formula for DMET.

Free Radical Scavenging Activity of Drops and Spray Containing Propolis-An EPR Examination.

PubMed

Olczyk, Pawel; Komosinska-Vassev, Katarzyna; Ramos, Pawel; Mencner, Lukasz; Olczyk, Krystyna; Pilawa, Barbara

2017-01-13

The influence of heating at a temperature of 50 °C and UV-irradiation of propolis drops and spray on their free radical scavenging activity was determined. The kinetics of interactions of the propolis samples with DPPH free radicals was analyzed. Interactions of propolis drops and propolis spray with free radicals were examined by electron paramagnetic resonance spectroscopy. A spectrometer generating microwaves of 9.3 GHz frequency was used. The EPR spectra of the model DPPH free radicals were compared with the EPR spectra of DPPH in contact with the tested propolis samples. The antioxidative activity of propolis drops and propolis spray decreased after heating at the temperature of 50 °C. A UV-irradiated sample of propolis drops more weakly scavenged free radicals than an untreated sample. The antioxidative activity of propolis spray increased after UV-irradiation. The sample of propolis drops heated at the temperature of 50 °C quenched free radicals faster than the unheated sample. UV-irradiation weakly changed the kinetics of propolis drops or spray interactions with free radicals. EPR analysis indicated that propolis drops and spray should not be stored at a temperature of 50 °C. Propolis drops should not be exposed to UV-irradiation.

Bubble formation during drop impact on a heated pool

NASA Astrophysics Data System (ADS)

Tian, Yuansi; Alhazmi, Muath; Kouraytem, Nadia; Thoroddsen, Sigurdur

2017-11-01

Ultra high-speed video imaging, at up to 200 kfps, is used to investigate a drop impinging onto a high temperature pool. The room-temperature perfluorohexane drop, which has a boiling temperature as low as 56 °C impacts on the soybean oil pool heated up to around 200 °C, which is overwhelmingly higher than the boiling temperature of the drop. The bottom of the drop is therefore covered by a layer of vapor which prevents contact between the two immiscible liquid surfaces, akin to the Leidenfrost effect However, as the pool temperature is reduced, one starts seeing contact and the dynamics transition into the vapor explosion regime. At the boundary of this regime we observe some entrapment of scattered or a toroidal ring of small bubbles. Experimental video data will be presented to show this novel phenomenon and explain how these bubbles are formed and evolve.

Solar Eclipse Effect on Shelter Air Temperature

NASA Technical Reports Server (NTRS)

Segal, M.; Turner, R. W.; Prusa, J.; Bitzer, R. J.; Finley, S. V.

1996-01-01

Decreases in shelter temperature during eclipse events were quantified on the basis of observations, numerical model simulations, and complementary conceptual evaluations. Observations for the annular eclipse on 10 May 1994 over the United States are presented, and these provide insights into the temporal and spatial changes in the shelter temperature. The observations indicated near-surface temperature drops of as much as 6 C. Numerical model simulations for this eclipse event, which provide a complementary evaluation of the spatial and temporal patterns of the temperature drops, predict similar decreases. Interrelationships between the temperature drop, degree of solar irradiance reduction, and timing of the peak eclipse are also evaluated for late spring, summer, and winter sun conditions. These simulations suggest that for total eclipses the drops in shelter temperature in midlatitudes can be as high as 7 C for a spring morning eclipse.

Enhancing interaural-delay-based extents of laterality at high frequencies by using ``transposed stimuli''

NASA Astrophysics Data System (ADS)

Bernstein, Leslie R.; Trahiotis, Constantine

2003-06-01

An acoustic pointing task was used to determine whether interaural temporal disparities (ITDs) conveyed by high-frequency ``transposed'' stimuli would produce larger extents of laterality than ITDs conveyed by bands of high-frequency Gaussian noise. The envelopes of transposed stimuli are designed to provide high-frequency channels with information similar to that conveyed by the waveforms of low-frequency stimuli. Lateralization was measured for low-frequency Gaussian noises, the same noises transposed to 4 kHz, and high-frequency Gaussian bands of noise centered at 4 kHz. Extents of laterality obtained with the transposed stimuli were greater than those obtained with bands of Gaussian noise centered at 4 kHz and, in some cases, were equivalent to those obtained with low-frequency stimuli. In a second experiment, the general effects on lateral position produced by imposed combinations of bandwidth, ITD, and interaural phase disparities (IPDs) on low-frequency stimuli remained when those stimuli were transposed to 4 kHz. Overall, the data were fairly well accounted for by a model that computes the cross-correlation subsequent to known stages of peripheral auditory processing augmented by low-pass filtering of the envelopes within the high-frequency channels of each ear.

Surgical transposition of the ovaries: imaging findings in 14 patients.

PubMed

Kier, R; Chambers, S K

1989-11-01

Pelvic radiation therapy for cervical or vaginal cancer often leads to ovarian failure. To remove the ovaries from the radiation portal and preserve their function, they can be transposed to the lateral abdomen. Serial imaging studies in 14 patients who had undergone ovarian transposition (five bilateral, nine unilateral) were reviewed. Images obtained included 32 CT scans, 20 sonograms, and one MR image. Most transposed ovaries were located along the paracolic gutters near the iliac crests, creating an extrinsic mass effect on adjacent bowel. Detection of surgical clips on the ovary on CT scans allowed confident recognition of all 19 transposed ovaries. Cysts in the transposed ovaries, noted on most imaging studies, did not correlate with complications of pain or hormonal dysfunction. In one case, a large physiologic cyst in a transposed ovary distorted the cecum and was mistaken for a mucocele of the appendix. In another case, a large ovarian cyst was thought to be tumor recurrence or a lymphocele. These findings indicate that although the transposed ovaries can be recognized on CT scans by the surgical clips attached to the ovaries, the appearance of the ovary does not predict reliably the development of complications.

Thermocapillary Migration and Interactions of Bubbles and Drops

NASA Technical Reports Server (NTRS)

Balasubramaniam, R.; Lacy, Claud E.; Wozniak, Guenter; Subramanian, R. Shankar

1996-01-01

When a drop or bubble is placed in another fluid and subjected to the action of a temperature gradient, the drop will move. Such motion is a direct consequence of the variation of interfacial tension with temperature, and is termed thermocapillary migration. This paper discusses results from experiments conducted in reduced gravity on the thermocapillary motion of bubbles and drops.

Cooling and solidification of liquid-metal drops in a gaseous atmosphere

NASA Technical Reports Server (NTRS)

Mccoy, J. K.; Markworth, A. J.; Collings, E. W.; Brodkey, R. S.

1992-01-01

The free fall of a liquid-metal drop, heat transfer from the drop to its environment, and solidification of the drop are described for both gaseous and vacuum atmospheres. A simple model, in which the drop is assumed to fall rectilinearly, with behavior like that of a rigid particle, is developed to describe cooling behavior. Recalescence of supercooled drops is assumed to occur instantaneously when a specified temperature is passed. The effects of solidification and experimental parameters on drop cooling are calculated and discussed. Major results include temperature as a function of time, and of drag, time to complete solidification, and drag as a function of the fraction of the drop solidified.

Model for determining vapor equilibrium rates in the hanging drop method for protein crystal growth

NASA Technical Reports Server (NTRS)

Baird, James K.; Frieden, Richard W.; Meehan, E. J., Jr.; Twigg, Pamela J.; Howard, Sandra B.; Fowlis, William A.

1987-01-01

An engineering analysis of the rate of evaporation of solvent in the hanging drop method of protein crystal growth is presented. Results are applied to 18 drop and well arrangements commonly encountered in the laboratory. The chemical nature of the salt, drop size and shape, drop concentration, well size, well concentration, and temperature are taken into account. The rate of evaporation increases with temperature, drop size, and the salt concentration difference between the drop and the well. The evaporation in this model possesses no unique half-life. Once the salt in the drop achieves 80 percent of its final concentration, further evaporation suffers from the law of diminishing returns.

Marangoni Flow Induced Evaporation Enhancement on Binary Sessile Drops.

PubMed

Chen, Pin; Harmand, Souad; Ouenzerfi, Safouene; Schiffler, Jesse

2017-06-15

The evaporation processes of pure water, pure 1-butanol, and 5% 1-butanol aqueous solution drops on heated hydrophobic substrates are investigated to determine the effect of temperature on the drop evaporation behavior. The evolution of the parameters (contact angle, diameter, and volume) during evaporation measured using a drop shape analyzer and the infrared thermal mapping of the drop surface recorded by an infrared camera were used in investigating the evaporation process. The pure 1-butanol drop does not show any thermal instability at different substrate temperatures, while the convection cells created by the thermal Marangoni effect appear on the surface of the pure water drop from 50 °C. Because 1-butanol and water have different surface tensions, the infrared video of the 5% 1-butanol aqueous solution drop shows that the convection cells are generated by the solutal Marangoni effect at any substrate temperature. Furthermore, when the substrate temperature exceeds 50 °C, coexistence of the thermal and solutal Marangoni flows is observed. By analyzing the relation between the ratio of the evaporation rate of pure water and 1-butanol aqueous solution drops and the Marangoni number, a series of empirical equations for predicting the evaporation rates of pure water and 1-butanol aqueous solution drops at the initial time as well as the equations for the evaporation rate of 1-butanol aqueous solution drop before the depletion of alcohol are derived. The results of these equations correspond fairly well to the experimental data.

Analysis of the convective evaporation of nondilute clusters of drops

NASA Technical Reports Server (NTRS)

Bellan, J.; Harstad, K.

1987-01-01

The penetration distance of an outer flow into a drop cluster volume is the critical, evaporation mode-controlling parameter in the present model for nondilute drop clusters' convective evaporation. The model is found to perform well for such low penetration distances as those obtained for dense clusters in hot environments and low relative velocities between the outer gases and the cluster. For large penetration distances, however, the predictive power of the model deteriorates; in addition, the evaporation time is found to be a weak function of the initial relative velocity and a strong function of the initial drop temperature. The results generally show that the interior drop temperature was transient throughout the drop lifetime, although temperature nonuniformities persisted up to the first third of the total evaporation time at most.

An experimental design for total container impact response modeling at extreme temperatures

NASA Technical Reports Server (NTRS)

Kobler, V. P.; Wyskida, R. M.; Johannes, J. D.

1979-01-01

An experimental design (a drop test) was developed to test the effects of confinement upon cushions. The drop test produced consistent corner void cushion data from which mathematical models were developed. A mathematical relationship between temperature and drop height was found.

Paleotemperature reconstruction from mammalian phosphate δ18O records - an alternative view on data processing

NASA Astrophysics Data System (ADS)

Skrzypek, Grzegorz; Sadler, Rohan; Wiśniewski, Andrzej

2017-04-01

The stable oxygen isotope composition of phosphates (δ18O) extracted from mammalian bone and teeth material is commonly used as a proxy for paleotemperature. Historically, several different analytical and statistical procedures for determining air paleotemperatures from the measured δ18O of phosphates have been applied. This inconsistency in both stable isotope data processing and the application of statistical procedures has led to large and unwanted differences between calculated results. This study presents the uncertainty associated with two of the most commonly used regression methods: least squares inverted fit and transposed fit. We assessed the performance of these methods by designing and applying calculation experiments to multiple real-life data sets, calculating in reverse temperatures, and comparing them with true recorded values. Our calculations clearly show that the mean absolute errors are always substantially higher for the inverted fit (a causal model), with the transposed fit (a predictive model) returning mean values closer to the measured values (Skrzypek et al. 2015). The predictive models always performed better than causal models, with 12-65% lower mean absolute errors. Moreover, the least-squares regression (LSM) model is more appropriate than Reduced Major Axis (RMA) regression for calculating the environmental water stable oxygen isotope composition from phosphate signatures, as well as for calculating air temperature from the δ18O value of environmental water. The transposed fit introduces a lower overall error than the inverted fit for both the δ18O of environmental water and Tair calculations; therefore, the predictive models are more statistically efficient than the causal models in this instance. The direct comparison of paleotemperature results from different laboratories and studies may only be achieved if a single method of calculation is applied. Reference Skrzypek G., Sadler R., Wiśniewski A., 2016. Reassessment of recommendations for processing mammal phosphate δ18O data for paleotemperature reconstruction. Palaeogeography, Palaeoclimatology, Palaeoecology 446, 162-167.

Effect of interface deformability on thermocapillary motion of a drop in a tube

NASA Astrophysics Data System (ADS)

Mahesri, S.; Haj-Hariri, H.; Borhan, A.

2014-03-01

The effect of an externally imposed axial temperature gradient on the mobility and deformation of a drop in an otherwise stagnant liquid within an insulated cylindrical tube is investigated. In the absence of bulk transport of momentum and energy, the boundary integral technique is used to obtain the flow and temperature fields inside and outside the deformable drop. The steady drop shapes and the corresponding migration velocities are examined over a wide range of the dimensionless parameters. The steady drop shape is nearly spherical for dimensionless drop sizes <0.5, but becomes slightly elongated in the axial direction for drop sizes comparable to tube diameter. The adverse effect of drop deformation on the effective temperature gradient driving the motion is slightly more pronounced than its favorable effect of reducing drag, thereby leading to a slight reduction in drop mobility with increasing drop deformation. Increasing the viscosity ratio reduces drop deformation and leads to a slight enhancement in the relative mobility (with respect to free thermocapillary motion) of confined drops. When the drop fluid has a lower thermal conductivity than the exterior phase, the presence of the thermally-insulating wall increases the thermal driving force for drop motion (compared to that for the same drop in unbounded domain) by causing more pronounced bending of the isotherms toward the drop. However, the favorable thermal effect of the confining wall is overwhelmed by its retarding hydrodynamic effect, causing the confined drop to always move slower than its unbounded counterpart regardless of the value of the thermal conductivity ratio.

Preservation of Biological Activity of Plasma and Platelet-Derived Eye Drops After Their Different Time and Temperature Conditions of Storage.

PubMed

Anitua, Eduardo; de la Fuente, María; Riestra, Ana; Merayo-Lloves, Jesús; Muruzábal, Francisco; Orive, Gorka

2015-09-01

To analyze whether plasma rich in growth factors (PRGF) eye drops preserve their biological characteristics and activity after storage for 3 and 6 months at -20°C, at 4°C, and at room temperature for 72 hours, compared with fresh samples (t0). Blood from 6 healthy donors was harvested and centrifuged to obtain PRGF free of leukocytes. Resulting PRGF eye drops were stored for 3 and 6 months at -20°C. At each time, 2 aliquots were maintained at room temperature or at 4°C for 72 hours. Platelet-derived growth factor-AB, transforming growth factor-β1, vascular endothelial growth factor, epidermal growth factor, insulin-like growth factor-1, angiopoietin-1, and thrombospondin-1 were quantified at each time and temperature of storage. Also, the effect of PRGF eye drops on proliferation of primary human keratocytes was evaluated. All the analyzed growth factor levels remained constant at each time and storage condition. No differences were observed in the proliferative activity of keratocytes after treatment with PRGF eye drops at any studied time or temperature. Finally, there was no microbial contamination in any of the PRGF eye drops. The preservation of the PRGF eye drops at -20°C for up to 3 and 6 months does not mean reduction of the main growth factors and proteins implicated in ocular surface wound healing. Eye drop characteristics and in vitro biological activity were not affected by their usage and conservation for 72 hours at 4°C or at room temperature.

Evaporation kinetics in the hanging drop method of protein crystal growth

NASA Technical Reports Server (NTRS)

Baird, James K.; Frieden, Richard W.; Meehan, E. J., Jr.; Twigg, Pamela J.; Howard, Sandra B.; Fowlis, William A.

1987-01-01

An engineering analysis of the rate of evaporation of solvent in the hanging drop method of protein crystal growth is presented; these results are applied to 18 different drop and well arrangements commonly encountered in the laboratory, taking into account the chemical nature of the salt, the drop size and shape, the drop concentration, the well size, the well concentration, and the temperature. It is found that the rate of evaporation increases with temperature, drop size, and with the salt concentration difference between the drop and the well. The evaporation possesses no unique half-life. Once the salt in the drop achieves about 80 percent of its final concentration, further evaporation suffers from the law of diminishing returns.

Orthodontic correction of a transposed maxillary canine and first premolar in the permanent dentition.

PubMed

Nishimura, Kazuaki; Nakao, Kimihisa; Aoki, Taijyu; Fuyamada, Mariko; Saito, Keisuke; Goto, Shigemi

2012-10-01

The patient was a 16-year-old Japanese girl whose chief complaints were crowding and transposition of the maxillary canine and first premolar. A setup model was used to preoperatively align the teeth in their transposed positions. The amount of postoperative reshaping was estimated for the occlusal surfaces of the teeth. However, the patient did not wish to have her teeth reduced by reshaping or to have composite materials for restorative camouflage. Because she strongly expected alignment of her teeth in the correct intra-arch position, her transposed teeth were corrected without extraction of the transposed teeth. Cone-beam computed tomography was used to obtain more detailed information about the transposition, and the direction of tooth movement was examined. Although the duration of the treatment was long, both the crowns and the roots of the transposed teeth were aligned correctly. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

[The role of external letter positions in visual word recognition].

PubMed

Perea, Manuel; Lupker, Sthephen J

2007-11-01

A key issue for any computational model of visual word recognition is the choice of an input coding schema, which is responsible for assigning letter positions. Such a schema must reflect the fact that, according to recent research, nonwords created by transposing letters (e.g., caniso for CASINO ), typically, appear to be more similar to the word than nonwords created by replacing letters (e.g., caviro ). In the present research, we initially carried out a computational analysis examining the degree to which the position of the transposition influences transposed-letter similarity effects. We next conducted a masked priming experiment with the lexical decision task to determine whether a transposed-letter priming advantage occurs when the first letter position is involved. Primes were created by either transposing the first and third letters (démula-MEDULA ) or replacing the first and third letters (bérula-MEDULA). Results showed that there was no transposed-letter priming advantage in this situation. We discuss the implications of these results for models of visual word recognition.

The relative immunity of high-frequency transposed stimuli to low-frequency binaural interference

NASA Astrophysics Data System (ADS)

Bernstein, Leslie R.; Trahiotis, Constantine

2004-05-01

We have recently demonstrated that high-frequency transposed stimuli, having envelopes designed to provide high-frequency channels with information similar to that normally available in only low-frequency channels, yield threshold-ITDs and extents of laterality comparable to those obtained with conventional low-frequency stimuli. This enhanced potency of ITDs conveyed by high-frequency transposed stimuli, as compared to conventional high-frequency stimuli, suggested to us that ITDs conveyed by transposed stimuli might be relatively immune to the presence of low-frequency binaural interferers. To investigate this issue, threshold-ITDs and extents of laterality were measured with a variety of conventional and transposed targets centered at 4 kHz. The targets were presented either in the presence or absence of a simultaneously gated diotic noise centered at 500 Hz, the interferer. As expected, the presence of the low-frequency interferer resulted in substantially elevated threshold-ITDs and reduced extents of laterality for the conventional high-frequency stimuli. In contrast, these interference effects were either greatly attenuated or absent for ITDs conveyed by the high-frequency transposed targets. The results will be discussed in the context of current models of binaural interference. [Work supported by NIH DC 04147, NIH DC04073, NIH DC 002304.

Satellite observations of surface temperature during the March 2015 total solar eclipse.

PubMed

Good, Elizabeth

2016-09-28

The behaviour of remotely sensed land surface temperatures (LSTs) from the spinning-enhanced visible and infrared imager (SEVIRI) during the total solar eclipse of 20 March 2015 is analysed over Europe. LST is found to drop by up to several degrees Celcius during the eclipse, with the minimum LST occurring just after the eclipse mid-point (median=+1.5 min). The drop in LST is typically larger than the drop in near-surface air temperatures reported elsewhere, and correlates with solar obscuration (r=-0.47; larger obscuration = larger LST drop), eclipse duration (r=-0.62; longer duration = larger LST drop) and time (r=+0.37; earlier eclipse = larger LST drop). Locally, the LST drop is also correlated with vegetation (up to r=+0.6), with smaller LST drops occurring over more vegetated surfaces. The LSTs at locations near the coast and at higher elevation are also less affected by the eclipse. This study covers the largest area and uses the most observations of eclipse-induced surface temperature drops to date, and is the first full characterization of satellite LST during an eclipse (known to the author). The methods described could be applied to Geostationary Operational Environmental Satellite (GOES) LST data over North America during the August 2017 total solar eclipse.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

Satellite observations of surface temperature during the March 2015 total solar eclipse

PubMed Central

2016-01-01

The behaviour of remotely sensed land surface temperatures (LSTs) from the spinning-enhanced visible and infrared imager (SEVIRI) during the total solar eclipse of 20 March 2015 is analysed over Europe. LST is found to drop by up to several degrees Celcius during the eclipse, with the minimum LST occurring just after the eclipse mid-point (median=+1.5 min). The drop in LST is typically larger than the drop in near-surface air temperatures reported elsewhere, and correlates with solar obscuration (r=−0.47; larger obscuration = larger LST drop), eclipse duration (r=−0.62; longer duration = larger LST drop) and time (r=+0.37; earlier eclipse = larger LST drop). Locally, the LST drop is also correlated with vegetation (up to r=+0.6), with smaller LST drops occurring over more vegetated surfaces. The LSTs at locations near the coast and at higher elevation are also less affected by the eclipse. This study covers the largest area and uses the most observations of eclipse-induced surface temperature drops to date, and is the first full characterization of satellite LST during an eclipse (known to the author). The methods described could be applied to Geostationary Operational Environmental Satellite (GOES) LST data over North America during the August 2017 total solar eclipse. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550764

Tectonic plates, D (double prime) thermal structure, and the nature of mantle plumes

NASA Technical Reports Server (NTRS)

Lenardic, A.; Kaula, W. M.

1994-01-01

It is proposed that subducting tectonic plates can affect the nature of thermal mantle plumes by determining the temperature drop across a plume source layer. The temperature drop affects source layer stability and the morphology of plumes emitted from it. Numerical models are presented to demonstrate how introduction of platelike behavior in a convecting temperature dependent medium, driven by a combination of internal and basal heating, can increase the temperature drop across the lower boundary layer. The temperature drop increases dramatically following introduction of platelike behavior due to formation of a cold temperature inversion above the lower boundary layer. This thermal inversion, induced by deposition of upper boundary layer material to the system base, decays in time, but the temperature drop across the lower boundary layer always remains considerably higher than in models lacking platelike behavior. On the basis of model-inferred boundary layer temperature drops and previous studies of plume dynamics, we argue that generally accepted notions as to the nature of mantle plumes on Earth may hinge on the presence of plates. The implication for Mars and Venus, planets apparently lacking plate tectonics, is that mantle plumes of these planets may differ morphologically from those of Earth. A corollary model-based argument is that as a result of slab-induced thermal inversions above the core mantle boundary the lower most mantle may be subadiabatic, on average (in space and time), if major plate reorganization timescales are less than those acquired to diffuse newly deposited slab material.

Measuring the Densities of Aqueous Glasses at Cryogenic Temperatures.

PubMed

Shen, Chen; Julius, Ethan F; Tyree, Timothy J; Dan, Ritwik; Moreau, David W; Thorne, Robert

2017-06-28

We demonstrate a method for determining the vitreous phase cryogenic temperature densities of aqueous mixtures, and other samples that require rapid cooling, to prepare the desired cryogenic temperature phase. Microliter to picoliter size drops are cooled by projection into a liquid nitrogen-argon (N2-Ar) mixture. The cryogenic temperature phase of the drop is evaluated using a visual assay that correlates with X-ray diffraction measurements. The density of the liquid N2-Ar mixture is adjusted by adding N2 or Ar until the drop becomes neutrally buoyant. The density of this mixture and thus of the drop is determined using a test mass and Archimedes principle. With appropriate care in drop preparation, management of gas above the liquid cryogen mixture to minimize icing, and regular mixing of the cryogenic mixture to prevent density stratification and phase separation, densities accurate to <0.5% of drops as small as 50 pL can readily be determined. Measurements on aqueous cryoprotectant mixtures provide insight into cryoprotectant action, and provide quantitative data to facilitate thermal contraction matching in biological cryopreservation.

Transposable elements in cancer.

PubMed

Burns, Kathleen H

2017-07-01

Transposable elements give rise to interspersed repeats, sequences that comprise most of our genomes. These mobile DNAs have been historically underappreciated - both because they have been presumed to be unimportant, and because their high copy number and variability pose unique technical challenges. Neither impediment now seems steadfast. Interest in the human mobilome has never been greater, and methods enabling its study are maturing at a fast pace. This Review describes the activity of transposable elements in human cancers, particularly long interspersed element-1 (LINE-1). LINE-1 sequences are self-propagating, protein-coding retrotransposons, and their activity results in somatically acquired insertions in cancer genomes. Altered expression of transposable elements and animation of genomic LINE-1 sequences appear to be hallmarks of cancer, and can be responsible for driving mutations in tumorigenesis.

Alcohol Poisoning

MedlinePlus

... tinged skin or pale skin Low body temperature (hypothermia) Passing out (unconsciousness) and can't be awakened ... level may drop low enough to cause seizures. Hypothermia. Your body temperature may drop so low that ...

Particle-size dependence of immersion freezing: Investigation of INUIT test aerosol particles with freely suspended water drops.

NASA Astrophysics Data System (ADS)

Diehl, Karoline; Debertshäuser, Michael; Eppers, Oliver; Jantsch, Evelyn; Mitra, Subir K.

2014-05-01

One goal of the research group INUIT (Ice Nuclei research UnIT) is to investigate the efficiencies of several test ice nuclei under comparable conditions but with different experimental techniques. In the present studies, two methods are used: the Mainz vertical wind tunnel and an acoustic levitator placed inside a cold chamber. In both cases drops are freely levitated, either at their terminal velocity in the wind tunnel updraft or around the nodes of a standing ultrasonic wave in the acoustic levitator. Thus, heat transfer conditions are well approximated, and wall contact effects on freezing as well as electrical charges of the drops are avoided. Drop radii are 370 μm and 1 mm, respectively. In the wind tunnel, drops are investigated at constant temperatures within a certain time period and the onset of freezing is observed directly. In the acoustic levitator, the drop temperature decreases during the experiments and is measured by an in-situ calibrated Infrared thermometer. The onset of freezing is indicated by a rapid rise of the drop surface temperature because of the release of latent heat. Investigated test ice nuclei are Snomax® as a proxy of biological particles and illite NX as well as K-feldspar as represents of mineral dust. The particle concentrations are 1 × 10-12 to 3 × 10-6 g Snomax® per drop and 5 × 10-9 to 5 × 10-5 g mineral dust per drop. Freezing temperatures are between -2 and -18° C in case of Snomax® and between -14 and -26° C in case of mineral dust. The lower the particle masses per drop the lower are the freezing temperatures. For similar particle concentrations in the drops, the median freezing temperatures determined by the two techniques agree well within the measurement errors. With the knowledge of the specific particle surface area of the mineral dusts, the results are interpreted also in terms of particle surface area per drop. Results from the wind tunnel experiments which are performed at constant temperatures indicate that the freezing times are shorter the lower the temperatures are. For evaluation and comparisons of the data, two models of heterogeneous freezing are applied, the stochastic and the time-independent singular description. The nucleation rate coefficients J(T) as well as the surface densities of active sites ns(T) or the numbers of active sites nm(T) are determined from the experimental data. It is shown that both models are suited to describe the present heterogeneous freezing results for the range of investigated particle masses or surface areas per drop. The comparison of the results from the two experimental techniques evaluated with the time-independent singular model indicates an excellent agreement within the measurement errors.

Expression responses of five cold tolerant related genes to two temperature dropping treatments in sea cucumber Apostichopus japonicus

NASA Astrophysics Data System (ADS)

Li, Chengze; Chang, Yaqing; Pang, Zhenguo; Ding, Jun; Ji, Nanjing

2015-03-01

Environmental conditions, including ambient temperature, play important roles in survival, growth development, and reproduction of the Japanese sea cucumber, Apostichopus japonicus. Low temperatures result in slowed growth and skin ulceration disease. In a previous study, we investigated the effect of low temperature on gene expression profiles in A. japonicus by suppression subtractive hybridization (SSH). Genes encoding Ferritin, Lysozyme, Hsp70, gp96, and AjToll were selected from a subtracted cDNA library of A. japonicus under acute cold stress. The transcriptional expression profiles of these genes were investigated in different tissues (coelomocyte, respiratory tree, intestine, longitudinal muscle) after exposure to acute and mild temperature dropping treatments. The results show that (1) the five cold-tolerance-related genes were found in all four tissues and the highest mRNA levels were observed in coelomocyte and respiratory tree; (2) under the temperature dropping treatments, three types of transcriptional regulation patterns were observed: primary suppression followed by up-regulation at -2°C, suppressed expression throughout the two treatments, and more rarely an initial stimulation followed by suppression; and (3) gene expression suppression was more severe under acute temperature dropping than under mild temperature dropping treatment. The five cold-tolerance-related genes that were distributed mainly in coelomocyte and respiratory tissues were generally down-regulated by low temperature stress but an inverse up-regulation event was found at the extreme temperature (-2°C).

Thermal stabilities of drops of burning thermoplastics under the UL 94 vertical test conditions.

PubMed

Wang, Yong; Zhang, Jun

2013-02-15

The properties of polymer melts will strongly affect the fire hazard of the pool induced by polymer melt flow. In this study the thermal stabilities of eight thermoplastic polymers as well as their melting drops generated under the UL 94 vertical burning test conditions were investigated by thermogravimetric experiments. It was found that the kinetic compensation effect existed for the decomposition reactions of the polymers and their drops. For polymethylmethacrylate (PMMA), high impact polystyrene (HIPS), poly(acrylonitrile-butadiene-styrene) (ABS), polyamide 6 (PA6), polypropylene (PP) and low density polyethylene (LDPE), the onset decomposition temperature and the two decomposition kinetic parameters (the pre-exponential factor and the activation energy) of the drop were less than those of the polymer. However, the onset decomposition temperature and the two kinetic parameters of PC's drop were greater than those of polycarbonate (PC). Interestingly, for polyethylenevinylacetate (EVA18) the drop hardly contained the vinyl acetate chain segments. Similarly, for the PMMA/LDPE blends and the PMMA/PP blends, when the volume fraction of PMMA was less than 50% the drop hardly contained PMMA, implying that the blend would not drip until PMMA burned away and its surface temperature approached the decomposition temperature of the continuous phase composed of LDPE or PP. Copyright © 2012 Elsevier B.V. All rights reserved.

Boiling regimes of impacting drops on a heated substrate under reduced pressure

NASA Astrophysics Data System (ADS)

van Limbeek, Michiel A. J.; Hoefnagels, Paul B. J.; Shirota, Minori; Sun, Chao; Lohse, Detlef

2018-05-01

We experimentally investigate the boiling behavior of impacting ethanol drops on a heated smooth sapphire substrate at pressures ranging from P =0.13 bar to atmospheric pressure. We employ frustrated total internal reflection imaging to study the wetting dynamics of the contact between the drop and the substrate. The spreading drop can be in full contact (contact boiling), it can partially touch (transition boiling), or the drop can be fully levitated (Leidenfrost boiling). We show that the temperature of the boundary between contact and transition boiling shows at most a weak dependence on the impact velocity, but a significant decrease with decreasing ambient gas pressure. A striking correspondence is found between the temperature of this boundary and the static Leidenfrost temperature for all pressures. We therefore conclude that both phenomena share the same mechanism and are dominated by the dynamics taking place at the contact line. On the other hand, the boundary between transition boiling and Leidenfrost boiling, i.e., the dynamic Leidenfrost temperature, increases for increasing impact velocity for all ambient gas pressures. Moreover, the dynamic Leidenfrost temperature coincides for pressures between P =0.13 and 0.54 bar, whereas for atmospheric pressure the dynamic Leidenfrost temperature is slightly elevated. This indicates that the dynamic Leidenfrost temperature is at most weakly dependent on the enhanced evaporation by the lower saturation temperature of the liquid.

Glide twinning and pseudotwinning in peristerite: Si,Al diffusional stabilization and implications for the peristerite solvus

NASA Astrophysics Data System (ADS)

Brown, William L.

1989-07-01

Albite glide pseudotwins related to grain-boundary stresses have been observed in an exsolved peristerite (Brown 1989). The glide operation transposes the pre-existing periodic oligoclase/albite lamellae and interfaces into a position rotated by only ˜0.5° in the pseudotwins, but transforms the indices from (1bar 80) outside to ( 081) inside the pseudotwin. The pseudotwin is anti-ordered with respect to Al and Si and both it and the transposed interface are unstable. They should revert to the initial state on stress removal. If however the stresses are maintained for a sufficiently long time, the pseudotwins are stabilized by inversion of Si,Al order and re-orientation of the interface by an angle of about 30° into a position close to \\underline {(1bar 80)} . The continuous lamellae break up into a series of discs by diffusion of NaSi and CaAl, the minimum diffusion path being about the same as the thickness of the lamellae. On extrapolating available interdiffusion data in Ab-rich plagioclases to low temperatures, possible diffusion times may be calculated. The calculated times are long so that either the peristerite miscibility gap must be at a higher temperature than previously supposed or the low-temperature interdiffusion coefficients must be higher than the extrapolated experimental ones, or both. From recent data on ordering in albite, the crest of the gap is estimated to lie close to 650 625° C at low pressure and it is possible that interdiffusion under natural conditions is facilitated by hydrogen (protons) in feldspars.

When a water drop freezes before it solidifies

NASA Astrophysics Data System (ADS)

Kavehpour, Pirouz; Davis, Stephen; Tavakoli, Faryar

2012-11-01

When a drop of liquid is placed on a substrate which temperature is below the melting point of the liquid, one would expect the drop to solidify instantaneously. However, many liquids, such as water, must be subcooled to solidify below its melting temperature due to homogeneous nucleation's high activation energy. Most of the drop solidification research, particularly for water, phase change is assumed to occur at equilibrium freezing temperature; however, this is not the case. We found that after a certain degree of supercooling, a kinetic based nucleation begins and latent heat of fusion is suddenly liberated, causing an increase in liquid temperature. At the end of this stage, approximately 20% of the drop is crystallized. This phenomenon is known among metallurgists as recalescence. This is followed by a slow solidification process at the melting point. As a water droplet spreads on a cold substrate, its contact line stops just prior to freezing inception from the liquid-solid interface. In this study, we assert that recalescence prior to solidification may be the cause of water's sudden immobility, which results in a fixed contact angle and droplet diameter. In our experiments, the nucleation front initiates from the trijunction point and propagates to the drop volume.

Ovarian metastasis in a transposed ovary 10 years after primary cervical cancer: the importance of histologic examination and review of literature.

PubMed

Janse, Julienne A; Sie-Go, Daisy M D S; Schreuder, Henk W R

2011-06-17

Cases of cervical carcinoma metastasing to the transposed ovary are rarely reported in the literature. In this report, the authors present the case of a 53-year-old woman with a persisting, unsuspected cyst in the right transposed ovary, 10 years after treatment for adenosquamous carcinoma of the cervix. It is the first report describing a secondary ovarian malignancy originating from a cervical adenosquamous carcinoma in a transposed ovary. In addition, this is the first account of an ovarian metastasis 10 years after primary treatment for cervical cancer. Furthermore, pathologic examination with immunohistochemistry and human papillomavirus genotyping played a key role in the diagnostic process, as the case did not raise suspicion by ultrasound findings neither by cytological examination after cytological aspiration or by appearance during surgery.

Structural physical approximation for the realization of the optimal singlet fraction with two measurements

NASA Astrophysics Data System (ADS)

Adhikari, Satyabrata

2018-04-01

Structural physical approximation (SPA) has been exploited to approximate nonphysical operation such as partial transpose. It has already been studied in the context of detection of entanglement and found that if the minimum eigenvalue of SPA to partial transpose is less than 2/9 then the two-qubit state is entangled. We find application of SPA to partial transpose in the estimation of the optimal singlet fraction. We show that the optimal singlet fraction can be expressed in terms of the minimum eigenvalue of SPA to partial transpose. We also show that the optimal singlet fraction can be realized using Hong-Ou-Mandel interferometry with only two detectors. Further we have shown that the generated hybrid entangled state between a qubit and a binary coherent state can be used as a resource state in quantum teleportation.

Maximum drop radius and critical Weber number for splashing in the dynamical Leidenfrost regime

NASA Astrophysics Data System (ADS)

Riboux, Guillaume; Gordillo, Jose Manuel

2015-11-01

At room temperature, when a drop impacts against a smooth solid surface at a velocity above the so called critical velocity for splashing, the drop loses its integrity and fragments into tiny droplets violently ejected radially outwards. Below this critical velocity, the drop simply spreads over the substrate. Splashing is also reported to occur for solid substrate temperatures above the Leidenfrost temperature, T, for which a vapor layer prevents the drop from touching the substrate. In this case, the splashing morphology largely differs from the one reported at room temperature because, thanks to the presence of the gas layer, the shear stresses on the liquid do not decelerate the ejected lamella. Our purpose here is to predict, for wall temperatures above T, the dependence of the critical impact velocity on the temperature of the substrate as well as the maximum spreading radius for impacting velocities below the critical velocity for splashing. This is done making use of boundary integral simulations, where the velocity and the height of the liquid layer at the root of the ejected lamella are calculated numerically. This information constitutes the initial conditions for the one dimensional mass and momentum equations governing the dynamics of the toroidal rim limiting the edge of the lamella.

The impact of dissociation on transposon-mediated disease control strategies.

PubMed

Marshall, John M

2008-03-01

Vector-borne diseases such as malaria and dengue fever continue to be a major health concern through much of the world. The emergence of chloroquine-resistant strains of malaria and insecticide-resistant mosquitoes emphasize the need for novel methods of disease control. Recently, there has been much interest in the use of transposable elements to drive resistance genes into vector populations as a means of disease control. One concern that must be addressed before a release is performed is the potential loss of linkage between a transposable element and a resistance gene. Transposable elements such as P and hobo have been shown to produce internal deletion derivatives at a significant rate, and there is concern that a similar process could lead to loss of the resistance gene from the drive system following a transgenic release. Additionally, transposable elements such as Himar1 have been shown to transpose significantly more frequently when free of exogenous DNA. Here, we show that any transposon-mediated gene drive strategy must have an exceptionally low rate of dissociation if it is to be effective. Additionally, the resistance gene must confer a large selective advantage to the vector to surmount the effects of a moderate dissociation rate and transpositional handicap.

Does letter position coding depend on consonant/vowel status? Evidence with the masked priming technique.

PubMed

Perea, Manuel; Acha, Joana

2009-02-01

Recently, a number of input coding schemes (e.g., SOLAR model, SERIOL model, open-bigram model, overlap model) have been proposed that capture the transposed-letter priming effect (i.e., faster response times for jugde-JUDGE than for jupte-JUDGE). In their current version, these coding schemes do not assume any processing differences between vowels and consonants. However, in a lexical decision task, Perea and Lupker (2004, JML; Lupker, Perea, & Davis, 2008, L&CP) reported that transposed-letter priming effects occurred for consonant transpositions but not for vowel transpositions. This finding poses a challenge for these recently proposed coding schemes. Here, we report four masked priming experiments that examine whether this consonant/vowel dissociation in transposed-letter priming is task-specific. In Experiment 1, we used a lexical decision task and found a transposed-letter priming effect only for consonant transpositions. In Experiments 2-4, we employed a same-different task - a task which taps early perceptual processes - and found a robust transposed-letter priming effect that did not interact with consonant/vowel status. We examine the implications of these findings for the front-end of the models of visual word recognition.

Evolutionary impact of transposable elements on genomic diversity and lineage-specific innovation in vertebrates.

PubMed

Warren, Ian A; Naville, Magali; Chalopin, Domitille; Levin, Perrine; Berger, Chloé Suzanne; Galiana, Delphine; Volff, Jean-Nicolas

2015-09-01

Since their discovery, a growing body of evidence has emerged demonstrating that transposable elements are important drivers of species diversity. These mobile elements exhibit a great variety in structure, size and mechanisms of transposition, making them important putative actors in organism evolution. The vertebrates represent a highly diverse and successful lineage that has adapted to a wide range of different environments. These animals also possess a rich repertoire of transposable elements, with highly diverse content between lineages and even between species. Here, we review how transposable elements are driving genomic diversity and lineage-specific innovation within vertebrates. We discuss the large differences in TE content between different vertebrate groups and then go on to look at how they affect organisms at a variety of levels: from the structure of chromosomes to their involvement in the regulation of gene expression, as well as in the formation and evolution of non-coding RNAs and protein-coding genes. In the process of doing this, we highlight how transposable elements have been involved in the evolution of some of the key innovations observed within the vertebrate lineage, driving the group's diversity and success.

Comparison of High Aspect Ratio Cooling Channel Designs for a Rocket Combustion Chamber with Development of an Optimized Design

NASA Technical Reports Server (NTRS)

Wadel, Mary F.

1998-01-01

An analytical investigation on the effect of high aspect ratio (height/width) cooling channels, considering different coolant channel designs, on hot-gas-side wall temperature and coolant pressure drop for a liquid hydrogen cooled rocket combustion chamber, was performed. Coolant channel design elements considered were: length of combustion chamber in which high aspect ratio cooling was applied, number of coolant channels, and coolant channel shape. Seven coolant channel designs were investigated using a coupling of the Rocket Thermal Evaluation code and the Two-Dimensional Kinetics code. Initially, each coolant channel design was developed, without consideration for fabrication, to reduce the hot-gas-side wall temperature from a given conventional cooling channel baseline. These designs produced hot-gas-side wall temperature reductions up to 22 percent, with coolant pressure drop increases as low as 7.5 percent from the baseline. Fabrication constraints for milled channels were applied to the seven designs. These produced hot-gas-side wall temperature reductions of up to 20 percent, with coolant pressure drop increases as low as 2 percent. Using high aspect ratio cooling channels for the entire length of the combustion chamber had no additional benefit on hot-gas-side wall temperature over using high aspect ratio cooling channels only in the throat region, but increased coolant pressure drop 33 percent. Independent of coolant channel shape, high aspect ratio cooling was able to reduce the hot-gas-side wall temperature by at least 8 percent, with as low as a 2 percent increase in coolant pressure drop. ne design with the highest overall benefit to hot-gas-side wall temperature and minimal coolant pressure drop increase was the design which used bifurcated cooling channels and high aspect ratio cooling in the throat region. An optimized bifurcated high aspect ratio cooling channel design was developed which reduced the hot-gas-side wall temperature by 18 percent and reduced the coolant pressure drop by 4 percent. Reductions of coolant mass flow rate of up to 50 percent were possible before the hot-gas-side wall temperature reached that of the baseline. These mass flow rate reductions produced coolant pressure drops of up to 57 percent.

Applying transpose matrix on advanced encryption standard (AES) for database content

NASA Astrophysics Data System (ADS)

Manurung, E. B. P.; Sitompul, O. S.; Suherman

2018-03-01

Advanced Encryption Standard (AES) is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) and has been adopted by the U.S. government and is now used worldwide. This paper reports the impact of transpose matrix integration to AES. Transpose matrix implementation on AES is aimed at first stage of chypertext modifications for text based database security so that the confidentiality improves. The matrix is also able to increase the avalanche effect of the cryptography algorithm 4% in average.

Mucin gene expression in human urothelium and in intestinal segments transposed into the urinary tract.

PubMed

N'Dow, J; Pearson, J P; Bennett, M K; Neal, D E; Robson, C N

2000-10-01

The repertoire of mucin (MUC) gene expression in the normal human urothelium is poorly defined and the alterations in MUC gene expression following transposition of intestinal segments into the urinary tract has not previously been studied. The aims of this study were to define MUC gene expression in the normal human urothelium; and in transposed intestinal segments. Non-isotopic in-situ hybridization was carried out using eight digoxigenin labeled oligonucleotide mucin gene probes (MUC 1 - 7). Immunohistochemistry using NCL-MUC1 and NCL-MUC2 monoclonal antibodies was performed on sections of paraffin-embedded tissues. Twenty-seven patients were investigated (normal human urothelium, n = 6; transposed ileal segments, n = 14 and normal ileal controls, n = 7). MUC1 and MUC4 were the predominant mucin genes expressed in the normal urothelium with MUC3 being expressed in a third of cases studied; MUC2, 5AC, 5B, 6 and 7 were not expressed. Despite the morphological changes seen in transposed ileal segments, MUC2 and MUC3 continued to be expressed in these segments albeit in a disorganised fashion. Both MUC1 and MUC4 were up-regulated in transposed ileal segments, genes expressed by the normal human urothelium. All eight mucin genes were expressed in an area of pyloric-type metaplasia found in one transposed ileal segment. In patients with clam enterocystoplasty there was evidence of increasing up-regulation of MUC2, 3, 4 and 5AC expression in the urothelium toward the anastomotic site. Transposition of ileal segments into the urinary tract results in up-regulation of MUC1 and MUC4, the predominant MUC genes expressed in the human bladder. The clinical implication of the up-regulation of some MUC genes toward the anastomotic site in patients with an enteroplasty and the aberrant expression of MUC5AC - MUC7 by transposed segments is at present unclear.

Homogeneous freezing of single sulfuric and nitric acid solution drops levitated in an acoustic trap

NASA Astrophysics Data System (ADS)

Diehl, Karoline; Ettner-Mahl, Matthias; Hannemann, Anke; Mitra, Subir K.

2009-10-01

The freezing temperatures of single supercooled drops of binary and ternary sulfuric and nitric acid solutions were measured while varying the acid concentration. An acoustic levitator was used which allows to freely suspend single solution drops in air without electrical charges thereby avoiding any electrical influences which may affect the freezing process. The drops of typically 500 µm in radius were monitored by a video camera during cooling cycles down to - 85 °C to simulate the upper tropospheric and stratospheric temperature range. The present data confirm that liquid solution droplets can be supercooled far below the equilibrium melting point by approximately 35 °C. They follow the general trend of the expected freezing temperatures for homogeneous ice nucleation.

Associative priming effects with visible, transposed-letter nonwords: JUGDE facilitates COURT.

PubMed

Perea, Manuel; Palti, Dafna; Gomez, Pablo

2012-04-01

Associative priming effects can be obtained with masked nonword primes or with masked pseudohomophone primes (e.g., judpe-COURT, tode-FROG), but not with visible primes. The usual explanation is that when the prime is visible, these stimuli no longer activate the semantic representations of their base words. Given the important role of transposed-letter stimuli (e.g., jugde) in visual word recognition, here we examined whether or not an associative priming effect could be obtained with visible transposed-letter nonword primes (e.g., jugde-COURT) in a series of lexical decision experiments. Results showed a sizable associative priming effect with visible transposed-letter nonword primes (i.e., jugde-COURT faster than neevr-COURT) in Experiments 1-3 that was close to that with word primes. In contrast, we failed to find a parallel effect with replacement-letter nonword primes (Experiment 2). These findings pose some constraints to models of visual word recognition.

Transposable Elements and Genetic Instabilities in Crop Plants

DOE R&D Accomplishments Database

Burr, B.; Burr, F.

1981-04-10

Transposable elements have long been associated with certain unstable loci in maize and have been intensively studied by McClintock and others. It is known that a transposable element can control the expression of the structural genes at the locus where it resides. These controlling elements in maize are now beginning to be studied at the molecular level. Using recombinant molecular probes we have been able to describe the changes induced by the controlling element Ds at the shrunken locus. Ds elements appear to be large and dissimilar insertions into the wild-type locus - two elements actually map within the transcribed region of the gene. Genetic instabilities have been described in other economically important plants but the bases for these phenomena have not been understood. We believe that it is likely that some of these instabilities are the result of transposable element activity much as in the case of maize.

Pressure-Drop Considerations in the Characterization of Dew-Point Transfer Standards at High Temperatures

NASA Astrophysics Data System (ADS)

Mitter, H.; Böse, N.; Benyon, R.; Vicente, T.

2012-09-01

During calibration of precision optical dew-point hygrometers (DPHs), it is usually necessary to take into account the pressure drop induced by the gas flow between the "point of reference" and the "point of use" (mirror or measuring head of the DPH) either as a correction of the reference dew-point temperature or as part of the uncertainty estimation. At dew-point temperatures in the range of ambient temperature and below, it is sufficient to determine the pressure drop for the required gas flow, and to keep the volumetric flow constant during the measurements. In this case, it is feasible to keep the dry-gas flow into the dew-point generator constant or to measure the flow downstream the DPH at ambient temperature. In normal operation, at least one DPH in addition to the monitoring DPH are used, and this operation has to be applied to each instrument. The situation is different at high dew-point temperatures up to 95 °C, the currently achievable upper limit reported in this paper. With increasing dew-point temperatures, the reference gas contains increasing amounts of water vapour and a constant dry-gas flow will lead to a significant enhanced volume flow at the conditions at the point of use, and therefore, to a significantly varying pressure drop depending on the applied dew-point temperature. At dew-point temperatures above ambient temperature, it is also necessary to heat the reference gas and the mirror head of the DPH sufficiently to avoid condensation which will additionally increase the volume flow and the pressure drop. In this paper, a method is provided to calculate the dry-gas flow rate needed to maintain a known wet-gas flow rate through a chilled mirror for a range of temperature and pressures.

Drop Hammer Tests with Three Oleo Strut Models and Three Different Shock Strut Oils at Low Temperatures

NASA Technical Reports Server (NTRS)

Kranz, M

1954-01-01

Drop hammer tests with different shock strut models and shock strut oils were performed at temperatures ranging to -40 C. The various shock strut models do not differ essentially regarding their springing and damping properties at low temperatures; however, the influence of the different shock strut oils on the springing properties at low temperatures varies greatly.

Peripheral temperature drop in response to anticipation and consumption of a signaled palatable reward in laying hens (Gallus domesticus).

PubMed

Moe, Randi Oppermann; Stubsjøen, Solveig Marie; Bohlin, Jon; Flø, Andreas; Bakken, Morten

2012-06-25

The present study describes effects of anticipation and consumption of a palatable reward on comb surface temperature. The purpose was to investigate temperature responses as a potential physiological indicator of positive emotional states in laying hens. A rise in body temperature in response to stimuli predictive of or during exposure to unpleasant events has been interpreted as evidence of emotions in mammals and avians. However, this phenomenon has so far only been studied during anticipation of or exposure to negative events; i.e., emotions of a negative valence. Infrared thermography was used to record potential alterations in comb surface temperature to a conditioned cue signaling a reward (mealworms) and during reward delivery. On average, comb temperature dropped 1.5 °C (95% CI: +/-1.2 °C) after exposure to CS and consumption of reward (p~0.0014) when initial comb temperature was above 30 °C. Such temperature drop indicates a peripheral vasoconstriction and has clear resemblances to emotional fever as seen during negative emotional states. Thus, we propose that a drop in peripheral temperature reflects emotional arousal more than emotional valence. Substantial temperature responses due to diet-induced thermogenesis were found, further emphasizing a cautious interpretation of altered comb temperature in studies of animal welfare. Copyright © 2012 Elsevier Inc. All rights reserved.

Jumping Genes: The Transposable DNAs of Bacteria.

ERIC Educational Resources Information Center

Berg, Claire M.; Berg, Douglas E.

1984-01-01

Transposons are transposable elements that carry genes for antibiotic resistance. Provides background information on the structure and organization of these "jumping genes" in bacteria. Also describes the use of transposons in tagging genes and lists pertinent references and resource materials. (DH)

Orthodontic Intervention to Impacted and Transposed Lower Canines

PubMed Central

Kılıç, Nihat

2017-01-01

Impacted and transposed teeth cause serious difficulties in tooth eruption and movement as well as esthetic and functional outcomes. Proper treatment planning including good biomechanical control is essential in order to avoid side effects during traction and aligning of the impacted and/or transposed teeth. The purpose of the present study was to present a successfully treated female patient having transposed and impacted lower canines by means of a modified lingual arch and fixed orthodontic appliance. A female patient aged 13 years and 9 months presented to the orthodontic department with a chief compliant of bilateral spacing and missing teeth in mandibular dentition. After leveling and creating sufficient space in the mandibular arch for the canines, a modified lingual arch was cemented to the mandibular first molars. The lingual arch had two hooks extending to the distobuccal areas of the canine spaces. Elastic chains were applied between the hooks on the lingual arch and the ligatures tied to the attachments on the canine crowns. The light forces generated by elastic materials caused impacted canines to erupt and tend towards their own spaces in the dental arch. As a result, impacted and transposed lower canines were properly positioned in their spaces, and the treatment results were stable during the retention period. PMID:28540090

Brain calcium - Role in temperature regulation.

NASA Technical Reports Server (NTRS)

Hanegan, J. L.; Williams, B. A.

1973-01-01

Perfusion of the preoptic-anterior hypothalamus with excess calcium ion in ground squirrels produces a drop in core temperature. The magnitude of the drop is directly dependent on ambient temperature. Respiration, heart rate, and oxygen consumption are also reduced during perfusion of calcium ion. It is concluded that the depression of body temperature during calcium ion perfusion is due to generalized depression of the neurons of the preoptic-anterior hypothalamus.

Drop dynamics in space and interference with acoustic field (M-15)

NASA Technical Reports Server (NTRS)

Yamanaka, Tatsuo

1993-01-01

The objective of the experiment is to study contactless positioning of liquid drops, excitation of capillary waves on the surface of acoustically levitated liquid drops, and deformation of liquid drops by means of acoustic radiation pressure. Contactless positioning technologies are very important in space materials processing because the melt is processed without contacting the wall of a crucible which can easily contaminate the melt specifically for high melting temperatures and chemically reactive materials. Among the contactless positioning technologies, an acoustic technology is especially important for materials unsusceptible to electromagnetic fields such as glasses and ceramics. The shape of a levitated liquid drop in the weightless condition is determined by its surface tension and the internal and external pressure distribution. If the surface temperature is constant and there exist neither internal nor external pressure perturbations, the levitated liquid drop forms a shape of perfect sphere. If temperature gradients on the surface and internal or external pressure perturbations exist, the liquid drop forms various modes of shapes with proper vibrations. A rotating liquid drop was specifically studied not only as a classical problem of theoretical mechanics to describe the shapes of the planets of the solar system, as well as their arrangement, but it is also more a contemporary problem of modern non-linear mechanics. In the experiment, we are expecting to observe various shapes of a liquid drop such as cocoon, tri-lobed, tetropod, multi-lobed, and doughnut.

Fundamentals of Mold Free Casting: Experimental and Computational Studies

NASA Technical Reports Server (NTRS)

Tryggvason, Gretar; Ceccio, Steven

1997-01-01

Researchers are developing the technology of 'Ballistic Particle Manufacturing' (BPM) in which individual drops are precisely layered onto a substrate, and the drops are deposited so as to prevent splatting. These individual drops will ultimately be combined to form a net-shape, three-dimensional object. Our understanding of controlled drop deposition as applied to BPM is far from complete. Process parameters include the size and temperature of the liquid metal drop, its impact velocity and trajectory, and the condition and temperature of the substrate. Quantitative knowledge of the fluid mechanics and heat transfer of drop deposition and solidification are necessary to fully optimize the manufacturing process and to control the material microstructure of the final part. The object of this study is to examine the dynamics of liquid metal drops as they impinge upon a solid surface and solidify under conditions consistent with BPM (i.e. conditions which produce non-splatting drops). A program of both numerical simulations and experiments will be conducted. Questions this study will address include the following: How do the deformation and solidification of the drop depend on the properties of the fluid drop and the solid substrate? How does the presence of previously deposited drops affect the impingement and solidification process? How does the impingement of the new drop affect already deposited material? How does the cooling rate and solidification of the drops influence the material microstructure?

Correlation between location of transposed ovary and function in cervical cancer patients who underwent radical hysterectomy.

PubMed

Yoon, Aera; Lee, Yoo-Young; Park, Won; Huh, Seung Jae; Choi, Chel Hun; Kim, Tae-Joong; Lee, Jeong-Won; Kim, Byoung-Gie; Bae, Duk-Soo

2015-05-01

The study investigated the association between the location of transposed ovaries and posttreatment ovarian function in patients with early cervical cancer (IB1-IIA) who underwent radical hysterectomy and ovarian transposition with or without adjuvant therapies. Retrospective medical records were reviewed to enroll the patients with early cervical cancer who underwent ovarian transposition during radical hysterectomy at Samsung Medical Center between July 1995 and July 2012. Serum follicle-stimulating hormone (FSH) level was used as a surrogate marker for ovarian function. Twenty-one patients were enrolled. The median age and body mass index (BMI) were 31 years (range, 24-39 years) and 21.3 kg/m² (range, 17.7-31.2 kg/m²), respectively. The median serum FSH level after treatment was 7.9 mIU/mL (range, 2.4-143.4 mIU/mL). The median distance from the iliac crest to transposed ovaries on erect plain abdominal x-ray was 0.5 cm (range, -2.7 to 5.2 cm). In multivariate analysis, posttreatment serum FSH levels were significantly associated with the location of transposed ovaries (β = -8.1, P = 0.032), concurrent chemoradiation (CCRT) as an adjuvant therapy (β = 71.08, P = 0.006), and BMI before treatment (underweight: β = -59.93, P = 0.05; overweight: β = -40.62, P = 0.041). Location of transposed ovaries, adjuvant CCRT, and BMI before treatment may be associated with ovarian function after treatment. We suggest that ovaries should be transposed as highly as possible during radical hysterectomy to preserve ovarian function in young patients with early cervical cancer who might be a candidate for adjuvant CCRT and who have low BMI before treatment.

Adjustable Augmented Rectus Muscle Transposition Surgery with or Without Ciliary Vessel Sparing for Abduction Deficiencies

PubMed Central

Hendler, Karen; Pineles, Stacy L.; Demer, Joseph L.; Yang, Dawn; Velez, Federico G.

2014-01-01

Background Vertical rectus transposition (VRT) is useful in abduction deficiencies. Posterior fixation sutures enhance the effect of VRT, but usually preclude the use of adjustable sutures. Augmentation of VRT by resection of the transposed muscles allows for an adjustable technique that can reduce induced vertical deviations and overcorrections. Methods We retrospectively reviewed the records of all patients undergoing adjustable partial or full tendon VRT augmented by resection of the transposed muscles. Ciliary vessels were preserved in most of the patients by either splitting the transposed muscle or by dragging the transposed muscle without disrupting the muscle insertion. Results Seven patients with abducens palsy and one with esotropic Duane syndrome were included. Both vertical rectus muscles were symmetrically resected by 3–5 mm. Preoperative central gaze esotropia of 30.6 ± 12.9Δ (range, 17–50Δ) decreased to 10.6 ± 8.8Δ (range, 0–25Δ) at the final visit (p = 0.003). Three patients required postoperative adjustment by recession of one of the transposed muscles due to an induced vertical deviation (mean 9.3Δ reduced to 0Δ), coupled with overcorrection (mean exotropia 11.3Δ reduced to 0 in two patients and exophoria 2Δ in one patient). At the final follow-up visit 3.8 ± 2.6 months postoperatively, one patient had a vertical deviation <4Δ, and none had overcorrection or anterior segment ischemia. Three patients required further surgery for recurrent esotropia. Conclusions Augmentation of VRT by resection of the transposed muscles can be performed with adjustable sutures and vessel-sparing technique. This allows for postoperative control of overcorrections and induced vertical deviations as well as less risk of anterior segment ischemia. PMID:24738948

Adjustable augmented rectus muscle transposition surgery with or without ciliary vessel sparing for abduction deficiencies.

PubMed

Hendler, Karen; Pineles, Stacy L; Demer, Joseph L; Yang, Dawn; Velez, Federico G

2014-06-01

Vertical rectus transposition (VRT) is useful in abduction deficiencies. Posterior fixation sutures enhance the effect of VRT, but usually preclude the use of adjustable sutures. Augmentation of VRT by resection of the transposed muscles allows for an adjustable technique that can reduce induced vertical deviations and overcorrections. We retrospectively reviewed the records of all patients undergoing adjustable partial or full tendon VRT augmented by resection of the transposed muscles. Ciliary vessels were preserved in most of the patients by either splitting the transposed muscle or by dragging the transposed muscle without disrupting the muscle insertion. Seven patients with abducens palsy and one with esotropic Duane syndrome were included. Both vertical rectus muscles were symmetrically resected by 3-5 mm. Preoperative central gaze esotropia of 30.6 ± 12.9Δ (range, 17-50Δ) decreased to 10.6 ± 8.8Δ (range, 0-25Δ) at the final visit (p = 0.003). Three patients required postoperative adjustment by recession of one of the transposed muscles due to an induced vertical deviation (mean 9.3Δ reduced to 0Δ), coupled with overcorrection (mean exotropia 11.3Δ reduced to 0 in two patients and exophoria 2Δ in one patient). At the final follow-up visit 3.8 ± 2.6 months postoperatively, one patient had a vertical deviation <4Δ, and none had overcorrection or anterior segment ischemia. Three patients required further surgery for recurrent esotropia. Augmentation of VRT by resection of the transposed muscles can be performed with adjustable sutures and vessel-sparing technique. This allows for postoperative control of overcorrections and induced vertical deviations as well as less risk of anterior segment ischemia.

Microscopic description of a drop on a solid surface.

PubMed

Ruckenstein, Eli; Berim, Gersh O

2010-06-14

Two approaches recently suggested for the treatment of macro- or nanodrops on smooth or rough, planar or curved, solid surfaces, based on fluid-fluid and fluid-solid interaction potentials are reviewed. The first one employs the minimization of the total potential energy of a drop by assuming that the drop has a well defined profile and a constant liquid density in its entire volume with the exception of the monolayer nearest to the surface where the density has a different value. As a result, a differential equation for the drop profile as well as the necessary boundary conditions are derived which involve the parameters of the interaction potentials and do not contain such macroscopic characteristics as the surface tensions. As a consequence, the macroscopic and microscopic contact angles which the drop profile makes with the surface can be calculated. The macroscopic angle is obtained via the extrapolation of the circular part of the drop profile valid at some distance from the surface up to the solid surface. The microscopic angle is formed at the intersection of the real profile (which is not circular near the surface) with the surface. The theory provides a relation between these two angles. The ranges of the microscopic parameters of the interaction potentials for which (i) the drop can have any height (volume), (ii) the drop can have a restricted height but unrestricted volume, and (iii) a drop cannot be formed on the surface were identified. The theory was also extended to the description of a drop on a rough surface. The second approach is based on a nonlocal density functional theory (DFT), which accounts for the inhomogeneity of the liquid density and temperature effects, features which are missing in the first approach. Although the computational difficulties restrict its application to drops of only several nanometers, the theory can be applied indirectly to macrodrops by calculating the surface tensions and using the Young equation to determine the contact angle. Employing the canonical ensemble version of the DFT, nanodrops on smooth and rough solid surfaces could be investigated and their characteristics, such as the drop profile, contact angle, as well as the fluid density distribution inside the drop can be determined as functions of the parameters of the interaction potentials and temperature. It was found that the contact angle of the drop has a simple (quasi)universal dependence on the energy parameter epsilon(fs) of the fluid-solid interaction potential and temperature. The main feature of this dependence is the existence of a fixed value theta(0) of the contact angle theta which separates the solid substrates (characterized by the energy parameter epsilon(fs) of the fluid-solid interaction potential) into two classes with respect to their temperature dependence. For theta>theta(0) the contact angle monotonously increases and for theta

Antimisting kerosene: Low temperature degradation and blending

NASA Technical Reports Server (NTRS)

Yavrouian, A.; Parikh, P.; Sarohia, V.

1988-01-01

The inline filtration characteristics of freshly blended and degraded antimisting fuels (AMK) at low temperature are examined. A needle valve degrader was modified to include partial recirculation of degraded fuel and heat addition in the bypass loop. A pressure drop across the needle valve of up to 4,000 psi was used. The pressure drop across a 325 mesh filter screen placed inline with the degrader and directly downstream of the needle valve was measured as a function of time for different values of pressure drop across the needle valve. A volume flux of 1 gpm/sq in was employed based on the frontal area of the screen. It was found that, at ambient temperatures, freshly blended AMK fuel could be degraded using a single pass degradation at 4,000 psi pressure drop across the needle valve to give acceptable filterability performance. At fuel temperatures below -20 C, degradation becomes increasingly difficult and a single pass technique results in unacceptable filtration performance. Recirculation of a fraction of the degraded fuel and heat addition in the bypass loop improved low temperature degradation performance. The problem is addressed of blending the AMK additive with Jet A at various base fuel temperatures.

A Brief History of the Status of Transposable Elements: From Junk DNA to Major Players in Evolution

PubMed Central

Biémont, Christian

2010-01-01

The idea that some genetic factors are able to move around chromosomes emerged more than 60 years ago when Barbara McClintock first suggested that such elements existed and had a major role in controlling gene expression and that they also have had a major influence in reshaping genomes in evolution. It was many years, however, before the accumulation of data and theories showed that this latter revolutionary idea was correct although, understandably, it fell far short of our present view of the significant influence of what are now known as “transposable elements” in evolution. In this article, I summarize the main events that influenced my thinking about transposable elements as a young scientist and the influence and role of these specific genomic elements in evolution over subsequent years. Today, we recognize that the findings about genomic changes affected by transposable elements have considerably altered our view of the ways in which genomes evolve and work. PMID:21156958

An efficient parallel-processing method for transposing large matrices in place.

PubMed

Portnoff, M R

1999-01-01

We have developed an efficient algorithm for transposing large matrices in place. The algorithm is efficient because data are accessed either sequentially in blocks or randomly within blocks small enough to fit in cache, and because the same indexing calculations are shared among identical procedures operating on independent subsets of the data. This inherent parallelism makes the method well suited for a multiprocessor computing environment. The algorithm is easy to implement because the same two procedures are applied to the data in various groupings to carry out the complete transpose operation. Using only a single processor, we have demonstrated nearly an order of magnitude increase in speed over the previously published algorithm by Gate and Twigg for transposing a large rectangular matrix in place. With multiple processors operating in parallel, the processing speed increases almost linearly with the number of processors. A simplified version of the algorithm for square matrices is presented as well as an extension for matrices large enough to require virtual memory.

Thermocapillary reorientation of Janus drops

NASA Astrophysics Data System (ADS)

Rosales, Rodolfo; Saenz, Pedro

2017-11-01

Janus drops, named after the Ancient Roman two-faced god, are liquid drops formed from two immiscible fluids. Experimental observations indicate that a Janus drop may re-orientate in response to an applied external thermal gradient due to the Marangoni effect. Depending on the angle between the interior interface and the direction of the temperature gradient, disparities in the physical properties of the constituent liquids may lead to asymmetries in the thermocapillary flow. As a result, the drop will move along a curved path until a torque-free configuration is achieved, point after which it will continue on a straight trajectory. Here, we present the results of a theoretical investigation of this realignment phenomenon in the Stokes regime and in the limit of non-deformable interfaces. A 3D semi-analytical method in terms of polar spherical harmonics is developed to characterize and rationalize the hydrodynamic response (forces and torques), flow (velocity and temperature distribution) and trajectory of a Janus drop moving during the temperature-driven reorientation process. Furthermore, we discuss how this phenomenon may be exploited to develop dynamically reconfigurable micro-lenses. This work was partially supported by the US National Science Foundation through Grants DMS-1614043 and DMS-1719637.

A relationship between peak temperature drop and velocity differential in a microburst

NASA Technical Reports Server (NTRS)

Proctor, Fred H.

1989-01-01

Results from numerical microburst simulations using the Terminal Area Simulation System (Proctor, 1987) are used to develop a relationship between wind velocity differential and peak temperature drop. The numerical model and the relationships derived from the model are described. The relationship between peak temperature drop and differential wind velocity is shown to be valid during microburst development, for all precipitation shaft intensities and diameters. It is found that the relationship is not valid for low-reflectivity microburst events or in the presence of ground-based stable layers. The use of the relationship in IR wind shear detection systems is considered.

Evolutionary trajectory of Pack-MULEs is determined by their epigenetic status

USDA-ARS?s Scientific Manuscript database

Acquisition and rearrangement of host genes by transposable elements is one mechanism to increase gene diversity. The rice genome is replete in such sequences and while ~3,000 Pack- Mutator-like transposable elements containing gene sequences (Pack-MULEs) have been identified, their function remains...

Detection and characterization of miniature inverted-repeat transposable elements in “Candidatus Liberibacter asiaticus”

USDA-ARS?s Scientific Manuscript database

Miniature inverted-repeat transposable elements (MITEs) are non-autonomous transposons (devoid a transposase gene, tps) involving insertion/deletion of genomic DNA in bacterial genomes influencing gene functions. No transposon has yet been reported in “Candidatus Liberibacter asiaticus”, an alpha-pr...

Transposed-Letter Priming across Inflectional Morpheme Boundaries

ERIC Educational Resources Information Center

Zargar, Ehsan Shafiee; Witzel, Naoko

2017-01-01

This study reports findings from two experiments testing whether a transposed-letter (TL) priming effect can be obtained when the transposition occurs across morphological boundaries. Previous studies have primarily tested derivationally complex words or compound words, but have not examined a more rule-based and productive morphological…

Design study of an advanced gas generator. [which can be ignited during start-up period of turbine engines

NASA Technical Reports Server (NTRS)

Kim, S.; Trinh, H. P.

1993-01-01

A gas generator which can be ignited reliably during the initial start-up period and offers fairly uniform gas temperature at the exit was studied numerically. Various sizes and shapes of the mixing enhancement devices and their positions were examined to evaluate the uniformity of the exit gas temperature and the change of internal pressure drop incurred by introducing the mixing enhancement devices. By introducing a turbulence ring and a splash plate with an appropriate size and position, it was possible to obtain fairly uniform gas temperature distributions and a maximum gas temperature that is within the design limit temperature of 1600 R at the generator exit. However, with the geometry studied, the pressure drop across the generator was great, approximately 1150 psi, to satisfy the assigned design limit temperature. If the design limit temperature is increased to 1650 R, the pressure drop across the generator could be lowered by as much as 350 psi.

TEs or not TEs? That is the evolutionary question.

PubMed

Vaknin, Keren; Goren, Amir; Ast, Gil

2009-10-23

Transposable elements (TEs) have contributed a wide range of functional sequences to their host genomes. A recent paper in BMC Molecular Biology discusses the creation of new transcripts by transposable element insertion upstream of retrocopies and the involvement of such insertions in tissue-specific post-transcriptional regulation.

A non-autonomous insect piggyBac trasposable element is mobile in tobacco

USDA-ARS?s Scientific Manuscript database

The piggyBac transposable element, originally isolated from a virus in an insect cell line, is a valuable molecular tool for transgenesis and mutagenesis of invertebrates. For heterologous transgenesis in a variety of mammals, transfer of the piggyBac transposable element from an ectopic plasmid onl...

The hobo transposable element has transposase-dependent and -independent excision activity in drosophilid species

USDA-ARS?s Scientific Manuscript database

Mobility of the hobo transposable element was determined for several strains of Drosophila melanogaster and several Drosophila species. Mobility was assessed by use of an in vivo transient assay in the soma of developing embryos, which monitored hobo excision from injected indicator plasmids. Excisi...

Choked flow of fluid nitrogen with emphasis on the thermodynamic critical region

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Simoneau, R. J.; Ehlers, R. C.

1972-01-01

Experimental measurements of critical flow rate and pressure ratio for nitrogen flowing through a nozzle are presented. Data for selected stagnation isotherms from 87.5 to 234 K with pressures to 9.3 MN/m2 are compared to an equilibrium model with real fluid properties and also a nonequilibrium model. Critical flow pressure ratio along an isotherm tends to peak while the flow rate indicates an inflection. The point is closely associated with the transposed critical temperature and represents a change in the fluid structure.

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

NASA Technical Reports Server (NTRS)

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

2004-01-01

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

A Broadband Microwave Radiometer Technique at X-band for Rain and Drop Size Distribution Estimation

NASA Technical Reports Server (NTRS)

Meneghini, R.

2005-01-01

Radiometric brightess temperatures below about 12 GHz provide accurate estimates of path attenuation through precipitation and cloud water. Multiple brightness temperature measurements at X-band frequencies can be used to estimate rainfall rate and parameters of the drop size distribution once correction for cloud water attenuation is made. Employing a stratiform storm model, calculations of the brightness temperatures at 9.5, 10 and 12 GHz are used to simulate estimates of path-averaged median mass diameter, number concentration and rainfall rate. The results indicate that reasonably accurate estimates of rainfall rate and information on the drop size distribution can be derived over ocean under low to moderate wind speed conditions.

Do Transposed-Letter Similarity Effects Occur at a Morpheme Level? Evidence for Morpho-Orthographic Decomposition

ERIC Educational Resources Information Center

Dunabeitia, Jon Andoni; Peream, Manuel; Carreiras, Manuel

2007-01-01

When does morphological decomposition occur in visual word recognition? An increasing body of evidence suggests the presence of early morphological processing. The present work investigates this issue via an orthographic similarity manipulation. Three masked priming lexical decision experiments were conducted to examine the transposed-letter…

A Stimulus Sampling Theory of Letter Identity and Order

ERIC Educational Resources Information Center

Norris, Dennis; Kinoshita, Sachiko; van Casteren, Maarten

2010-01-01

Early on during word recognition, letter positions are not accurately coded. Evidence for this comes from transposed-letter (TL) priming effects, in which letter strings generated by transposing two adjacent letters (e.g., "jugde") produce large priming effects, more than primes with the letters replaced in the corresponding position (e.g.,…

[Plant transposable elements and their application in genetics and biotechnology].

PubMed

Ovcharenko, O O; Rudas, V A; Kuchuk, M V

2006-01-01

Data concerning plant transposable elements and their contribution to plant genome evolution are reviewed. Much attention is focused on utilization of transgenic plants as heterologous hosts of transposons for investigation of transposition mechanisms and gene cloning. Probable ways of the use of plant transposons as genetic tools in biotechnology are discussed.

Does Kaniso activate CASINO?: input coding schemes and phonology in visual-word recognition.

PubMed

Acha, Joana; Perea, Manuel

2010-01-01

Most recent input coding schemes in visual-word recognition assume that letter position coding is orthographic rather than phonological in nature (e.g., SOLAR, open-bigram, SERIOL, and overlap). This assumption has been drawn - in part - by the fact that the transposed-letter effect (e.g., caniso activates CASINO) seems to be (mostly) insensitive to phonological manipulations (e.g., Perea & Carreiras, 2006, 2008; Perea & Pérez, 2009). However, one could argue that the lack of a phonological effect in prior research was due to the fact that the manipulation always occurred in internal letter positions - note that phonological effects tend to be stronger for the initial syllable (Carreiras, Ferrand, Grainger, & Perea, 2005). To reexamine this issue, we conducted a masked priming lexical decision experiment in which we compared the priming effect for transposed-letter pairs (e.g., caniso-CASINO vs. caviro-CASINO) and for pseudohomophone transposed-letter pairs (kaniso-CASINO vs. kaviro-CASINO). Results showed a transposed-letter priming effect for the correctly spelled pairs, but not for the pseudohomophone pairs. This is consistent with the view that letter position coding is (primarily) orthographic in nature.

The struggle for life of the genome's selfish architects

PubMed Central

2011-01-01

Transposable elements (TEs) were first discovered more than 50 years ago, but were totally ignored for a long time. Over the last few decades they have gradually attracted increasing interest from research scientists. Initially they were viewed as totally marginal and anecdotic, but TEs have been revealed as potentially harmful parasitic entities, ubiquitous in genomes, and finally as unavoidable actors in the diversity, structure, and evolution of the genome. Since Darwin's theory of evolution, and the progress of molecular biology, transposable elements may be the discovery that has most influenced our vision of (genome) evolution. In this review, we provide a synopsis of what is known about the complex interactions that exist between transposable elements and the host genome. Numerous examples of these interactions are provided, first from the standpoint of the genome, and then from that of the transposable elements. We also explore the evolutionary aspects of TEs in the light of post-Darwinian theories of evolution. Reviewers This article was reviewed by Jerzy Jurka, Jürgen Brosius and I. King Jordan. For complete reports, see the Reviewers' reports section. PMID:21414203

Letter position coding across modalities: the case of Braille readers.

PubMed

Perea, Manuel; García-Chamorro, Cristina; Martín-Suesta, Miguel; Gómez, Pablo

2012-01-01

The question of how the brain encodes letter position in written words has attracted increasing attention in recent years. A number of models have recently been proposed to accommodate the fact that transposed-letter stimuli like jugde or caniso are perceptually very close to their base words. Here we examined how letter position coding is attained in the tactile modality via Braille reading. The idea is that Braille word recognition may provide more serial processing than the visual modality, and this may produce differences in the input coding schemes employed to encode letters in written words. To that end, we conducted a lexical decision experiment with adult Braille readers in which the pseudowords were created by transposing/replacing two letters. We found a word-frequency effect for words. In addition, unlike parallel experiments in the visual modality, we failed to find any clear signs of transposed-letter confusability effects. This dissociation highlights the differences between modalities. The present data argue against models of letter position coding that assume that transposed-letter effects (in the visual modality) occur at a relatively late, abstract locus.

Functional Anatomy of Recognition of Chinese Multi-Character Words: Convergent Evidence from Effects of Transposable Nonwords, Lexicality, and Word Frequency.

PubMed

Lin, Nan; Yu, Xi; Zhao, Ying; Zhang, Mingxia

2016-01-01

This fMRI study aimed to identify the neural mechanisms underlying the recognition of Chinese multi-character words by partialling out the confounding effect of reaction time (RT). For this purpose, a special type of nonword-transposable nonword-was created by reversing the character orders of real words. These nonwords were included in a lexical decision task along with regular (non-transposable) nonwords and real words. Through conjunction analysis on the contrasts of transposable nonwords versus regular nonwords and words versus regular nonwords, the confounding effect of RT was eliminated, and the regions involved in word recognition were reliably identified. The word-frequency effect was also examined in emerged regions to further assess their functional roles in word processing. Results showed significant conjunctional effect and positive word-frequency effect in the bilateral inferior parietal lobules and posterior cingulate cortex, whereas only conjunctional effect was found in the anterior cingulate cortex. The roles of these brain regions in recognition of Chinese multi-character words were discussed.

Functional Anatomy of Recognition of Chinese Multi-Character Words: Convergent Evidence from Effects of Transposable Nonwords, Lexicality, and Word Frequency

PubMed Central

Lin, Nan; Yu, Xi; Zhao, Ying; Zhang, Mingxia

2016-01-01

This fMRI study aimed to identify the neural mechanisms underlying the recognition of Chinese multi-character words by partialling out the confounding effect of reaction time (RT). For this purpose, a special type of nonword—transposable nonword—was created by reversing the character orders of real words. These nonwords were included in a lexical decision task along with regular (non-transposable) nonwords and real words. Through conjunction analysis on the contrasts of transposable nonwords versus regular nonwords and words versus regular nonwords, the confounding effect of RT was eliminated, and the regions involved in word recognition were reliably identified. The word-frequency effect was also examined in emerged regions to further assess their functional roles in word processing. Results showed significant conjunctional effect and positive word-frequency effect in the bilateral inferior parietal lobules and posterior cingulate cortex, whereas only conjunctional effect was found in the anterior cingulate cortex. The roles of these brain regions in recognition of Chinese multi-character words were discussed. PMID:26901644

Anomalous interfacial tension temperature dependence of condensed phase drops in magnetic fluids

NASA Astrophysics Data System (ADS)

Ivanov, Aleksey S.

2018-05-01

Interfacial tension temperature dependence σ(T) of the condensed phase (drop-like aggregates) in magnetic fluids undergoing field induced phase transition of the "gas-liquid" type was studied experimentally. Numerical analysis of the experimental data has revealed the anomalous (if compared to ordinary one-component fluids) behavior of the σ(T) function for all tested magnetic colloid samples: the condensed phase drops at high T ≈ 75 C exhibit higher σ(T) than the drops condensed at low T ≈ 20 C. The σ(T) behavior is explained by the polydispersity of magnetic colloids: at high T, only the largest colloidal particles are able to take part in the field induced condensation; thus, the increase of T causes the growth of the average particle diameters inside the drop-like aggregates, what in its turn results in the growth of σ(T). The result is confirmed by qualitative theoretical estimations and qualitative experimental observation of the condensed phase "evaporation" process after the applied magnetic field is removed: the drops that are formed due to capillary instability of the drop-like aggregates retract by one order of magnitude faster at high T, and the evaporation of the drops slows down at high T.

40 CFR 63.11567 - Who implements and enforces this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Processing and Asphalt Roofing Manufacturing Other Requirements and Information § 63.11567 Who implements and...). 2. A high-efficiency air filter or fiber bed filter a. Inlet gas temperature b, andb. Pressure drop... the inlet gas temperature and pressure drop, you can use a leak detection system that identifies when...

40 CFR Table 4 of Subpart Aaaaaaa... - Operating Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... Roofing Manufacturing Other Requirements and Information Who implements and enforces this subpart? Pt. 63... filter or fiber bed filter a. Inlet gas temperature b, andb. Pressure drop across device b The 3-hour... temperature and pressure drop, you can use a leak detection system that identifies when the filter media has...

40 CFR Table 4 of Subpart Aaaaaaa... - Operating Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... Roofing Manufacturing Other Requirements and Information Who implements and enforces this subpart? Pt. 63... filter or fiber bed filter a. Inlet gas temperature b, andb. Pressure drop across device b The 3-hour... temperature and pressure drop, you can use a leak detection system that identifies when the filter media has...

Rapid inactivation of the maize transposable element En/Spm in Medicago truncatula.

PubMed

d'Erfurth, I; Cosson, V; Eschstruth, A; Rippa, S; Messinese, E; Durand, P; Trinh, H; Kondorosi, A; Ratet, P

2003-09-01

Transposable elements have been widely used as mutagens in many organisms. Among them, the maize transposable element En/Spm has been shown to transpose efficiently in several plant species including the model plant Arabidopsis, where it has been used for large-scale mutagenesis. To determine whether we could use this transposon as a mutagen in the model legume plant Medicago truncatula, we tested the activity of the autonomous element, as well as two defective elements, in this plant, and in Arabidopsis as a positive control. In agreement with previous reports, we observed efficient excision of the autonomous En/Spm element in A. thaliana. This element was also active in M. truncatula, but the transposition activity was low and was apparently restricted to the tissue culture step necessary for the production of transgenic plants. The activity of one of the defective transposable elements, dSpm, was very low in A. thaliana and even lower in M. truncatula. The use of different sources of transposases suggested that this defect in transposition was associated with the dSpm element itself. Transposition of the other defective element, I6078, was also detected in M. truncatula, but, as observed with the autonomous element, transposition events were very rare and occurred during tissue culture. These results suggest that the En/Spm element is rapidly inactivated in the regenerated plants and their progeny, and therefore is not suitable for routine insertion mutagenesis in M. truncatula.

Fundamental study of FC-72 pool boiling surface temperature fluctuations and bubble behavior

NASA Astrophysics Data System (ADS)

Griffin, Alison R.

A heater designed to monitor surface temperature fluctuations during pool boiling experiments while the bubbles were simultaneously being observed has been fabricated and tested. The heat source was a transparent indium tin oxide (ITO) layer commercially deposited on a fused quartz substrate. Four copper-nickel thin film thermocouples (TFTCs) on the heater surface measured the surface temperature, while a thin layer of sapphire or fused silica provided electrical insulation between the TFTCs and the ITO. The TFTCs were micro-fabricated using the liftoff process to deposit the nickel and copper metal films. The TFTC elements were 50 mum wide and overlapped to form a 25 mum by 25 mum junction. TFTC voltages were recorded by a DAQ at a sampling rate of 50 kHz. A high-speed CCD camera recorded bubble images from below the heater at 2000 frames/second. A trigger sent to the camera by the DAQ synchronized the bubble images and the surface temperature data. As the bubbles and their contact rings grew over the TFTC junction, correlations between bubble behavior and surface temperature changes were demonstrated. On the heaters with fused silica insulation layers, 1--2°C temperature drops on the order of 1 ms occurred as the contact ring moved over the TFTC junction during bubble growth and as the contact ring moved back over the TFTC junction during bubble departure. These temperature drops during bubble growth and departure were due to microlayer evaporation and liquid rewetting the heated surface, respectively. Microlayer evaporation was not distinguished as the primary method of heat removal from the surface. Heaters with sapphire insulation layers did not display the measurable temperature drops observed with the fused silica heaters. The large thermal diffusivity of the sapphire compared to the fused silica was determined as the reason for the absence of these temperature drops. These findings were confirmed by a comparison of temperature drops in a 2-D simulation of a bubble growing over the TFTC junction on both the sapphire and fused silica heater surfaces. When the fused silica heater produced a temperature drop of 1.4°C, the sapphire heater produced a drop of only 0.04°C under the same conditions. These results verified that the lack of temperature drops present in the sapphire data was due to the thermal properties of the sapphire layer. By observing the bubble departure frequency and site density on the heater, as well as the bubble departure diameter, the contribution of nucleate boiling to the overall heat removal from the surface could be calculated. These results showed that bubble vapor generation contributed to approximately 10% at 1 W/cm2, 23% at 1.75 W/cm2, and 35% at 2.9 W/cm 2 of the heat removed from a fused silica heater. Bubble growth and contact ring growth were observed and measured from images obtained with the high-speed camera. Bubble data recorded on a fused silica heater at 3 W/cm2, 4 W/cm2, and 5 W/cm 2 showed that bubble departure diameter and lifetime were negligibly affected by the increase in heat flux. Bubble and contact ring growth rates demonstrated significant differences when compared on the fused silica and sapphire heaters at 3 W/cm2. The bubble departure diameters were smaller, the bubble lifetimes were longer, and the bubble departure frequency was larger on the sapphire heater, while microlayer evaporation was faster on the fused silica heater. Additional considerations revealed that these differences may be due to surface conditions as well as differing thermal properties. Nucleate boiling curves were recorded on the fused silica and sapphire heaters by adjusting the heat flux input and monitoring the local surface temperature with the TFTCs. The resulting curves showed a temperature drop at the onset of nucleate boiling due to the increase in heat transfer coefficient associated with bubble nucleation. One of the TFTC locations on the sapphire heater frequently experienced a second temperature drop at a higher heat flux. When the heat flux was started from 1 W/cm2 instead of zero or returned to zero only momentarily, the temperature overshoot did not occur. In these cases sufficient vapor remained in the cavities to initiate boiling at a lower superheat.

The motion of bubbles inside drops in containerless processing

NASA Technical Reports Server (NTRS)

Shankar, N.; Annamalai, P.; Cole, R.; Subramanian, R. S.

1982-01-01

A theoretical model of thermocapillary bubble motion inside a drop, located in a space laboratory, due to an arbitrary axisymmetric temperature distribution on the drop surface was constructed. Typical results for the stream function and temperature fields as well as the migration velocity of the bubble were obtained in the quasistatic limit. The motion of bubbles in a rotating body of liquid was studied experimentally, and an approximate theoretical model was developed. Comparison of the experimental observations of the bubble trajectories and centering times with theoretical predictions lends qualified support to the theory.

Numerical simulations of sessile droplet evaporating on heated substrate

NASA Astrophysics Data System (ADS)

Chen, Xue; Chen, Paul G.; Ouazzani, Jalil; Liu, Qiusheng

2017-04-01

Motivated by the space project EFILE, a 2D axisymmetric numerical model in the framework of ALE method is developed to investigate the coupled physical mechanism during the evaporation of a pinned drop that partially wets on a heated substrate. The model accounts for mass transport in surrounding air, Marangoni convection inside the drop and heat conduction in the substrate as well as moving interface. Numerical results predict simple scaling laws for the evaporation rate which scales linearly with drop radius but follows a power-law with substrate temperature. It is highlighted that thermal effect of the substrate has a great impact on the temperature profile at the drop surface, which leads to a multicellular thermocapillary flow pattern. In particular, the structure of the multicellular flow behavior induced within a heated drop is mainly controlled by a geometric parameter (aspect ratio). A relationship between the number of thermal cells and the aspect ratio is proposed.

The Quiet Clam Is Quite Calm: Transposed-Letter Neighborhood Effects on Eye Movements during Reading

ERIC Educational Resources Information Center

Johnson, Rebecca L.

2009-01-01

In responses time tasks, inhibitory neighborhood effects have been found for word pairs that differ in a transposition of two adjacent letters (e.g., "clam/calm"). Here, the author describes two eye-tracking experiments conducted to explore transposed-letter (TL) neighborhood effects within the context of normal silent reading. In…

The diversity of sequence and chromosomal distribution of new transposable element-related segments in the rye genome revealed by FISH and lineage annotation

USDA-ARS?s Scientific Manuscript database

The rye genome features a high percentage of repetitive elements, especially transposable elements (TEs). However, studies about the constitution and organization of TEs on rye chromosomes are limited. In this study, 97 unique TE segments were isolated and characterized; 50 TE segmemts showed varyin...

Transposed Letter Priming with Horizontal and Vertical Text in Japanese and English Readers

ERIC Educational Resources Information Center

Witzel, Naoko; Qiao, Xiaomei; Forster, Kenneth

2011-01-01

It is well established that in masked priming, a target word (e.g., "JUDGE") is primed more effectively by a transposed letter (TL) prime (e.g., "jugde") than by an orthographic control prime (e.g., "junpe"). This is inconsistent with the slot coding schemes used in many models of visual word recognition. Several…

Genotype dependent burst of transposable element expression in crowns of hexaploid wheat (Triticum aestivum L.) during cold acclimation

USDA-ARS?s Scientific Manuscript database

The expression of 1,613 transposable elements (TEs) represented in the Affymetix Wheat Genome Chip was examined during cold treatment in crowns of 4 hexaploid wheat genotypes that vary in tolerance to cold and in flowering time. The TE expression profiles showed a constant level of expression throug...

A steady state pressure drop model for screen channel liquid acquisition devices

NASA Astrophysics Data System (ADS)

Hartwig, J. W.; Darr, S. R.; McQuillen, J. B.; Rame, E.; Chato, D. J.

2014-11-01

This paper presents the derivation of a simplified one dimensional (1D) steady state pressure drop model for flow through a porous liquid acquisition device (LAD) inside a cryogenic propellant tank. Experimental data is also presented from cryogenic LAD tests in liquid hydrogen (LH2) and liquid oxygen (LOX) to compare against the simplified model and to validate the model at cryogenic temperatures. The purpose of the experiments was to identify the various pressure drop contributions in the analytical model which govern LAD channel behavior during dynamic, steady state outflow. LH2 pipe flow of LAD screen samples measured the second order flow-through-screen (FTS) pressure drop, horizontal LOX LAD outflow tests determined the relative magnitude of the third order frictional and dynamic losses within the channel, while LH2 inverted vertical outflow tests determined the magnitude of the first order hydrostatic pressure loss and validity of the full 1D model. When compared to room temperature predictions, the FTS pressure drop is shown to be temperature dependent, with a significant increase in flow resistance at LH2 temperatures. Model predictions of frictional and dynamic losses down the channel compare qualitatively with LOX LADs data. Meanwhile, the 1D model predicted breakdown points track the trends in the LH2 inverted outflow experimental results, with discrepancies being due to a non-uniform injection velocity across the LAD screen not accounted for in the model.

Temperature-mediated absorption of phenylmercuric nitrate on polyethylene and polypropylene containers in chloramphenicol eye drops.

PubMed

Charoo, Naseem; Chiew, Magdalene; Tay, Amelia; Lian, Lai

2014-09-01

The aim of this work was to find the effect of temperature and manufacturing source of phenylmercuric nitrate (PMN) on PMN absorption on low-density polyethylene (LDPE) and polypropylene containers in chloramphenicol eye drops. Two factorial experiments were designed to study the effect of temperature on PMN assay in chloramphenicol eye drops stored in LDPE and prepared from two different PMN sources. PMN source had no effect on PMN assay at 2-8 °C, however at stress conditions (30 °C/75%RH) for 3 weeks, the effect of PMN source on PMN assay was found significant (p < 0.05) in formulations stored in LDPE bottles. Temperature was the major contributor to decreased PMN assay. In formulations stored in polypropylene containers, PMN source had significant effect on PMN assay at 2-8 °C and 30 °C/75%RH. Overall, new PMN and polypropylene bottles performed better. The eye drops complied with preservative efficacy test both initially and at the end of shelf life. The concentration exponent of PMN is very low and in spite of its high absorption by container/closure, PMN was still able to protect the eye drops at the end of shelf life. It can be inferred that preservative efficacy test is the better indicator of preservative activity.

Thermal activation of superheated lipid-coated perfluorocarbon drops.

PubMed

Mountford, Paul A; Thomas, Alec N; Borden, Mark A

2015-04-28

This study explored the thermal conditions necessary for the vaporization of superheated perfluorocarbon nanodrops. Droplets C3F8 and C4F10 coated with a homologous series of saturated diacylphosphatidylcholines were formed by condensation of 4 μm diameter microbubbles. These drops were stable at room temperature and atmospheric pressure, but they vaporized back into microbubbles at higher temperatures. The vaporization transition was measured as a function of temperature by laser light extinction. We found that C3F8 and C4F10 drops experienced 90% vaporization at 40 and 75 °C, respectively, near the theoretical superheat limits (80-90% of the critical temperature). We therefore conclude that the metastabilty of these phase-change agents arises not from the droplet Laplace pressure altering the boiling point, as previously reported, but from the metastability of the pure superheated fluid to homogeneous nucleation. The rate of C4F10 drop vaporization was quantified at temperatures ranging from 55 to 75 °C, and an apparent activation energy barrier was calculated from an Arrhenius plot. Interestingly, the activation energy increased linearly with acyl chain length from C14 to C20, indicating that lipid interchain cohesion plays an important role in suppressing the vaporization rate. The vaporized drops (microbubbles) were found to be unstable to dissolution at high temperatures, particularly for C14 and C16. However, proper choice of the fluorocarbon and lipid species provided a nanoemulsion that could undergo at least ten reversible condensation/vaporization cycles. The vaporization properties presented in this study may facilitate the engineering of tunable phase-shift particles for diagnostic imaging, targeted drug delivery, tissue ablation, and other applications.

Molecular dynamics study of the vaporization of an ionic drop.

PubMed

Galamba, N

2010-09-28

The melting of a microcrystal in vacuum and subsequent vaporization of a drop of NaCl were studied through molecular dynamics simulations with the Born-Mayer-Huggins-Tosi-Fumi rigid-ion effective potential. The vaporization was studied for a single isochor at increasing temperatures until the drop completely vaporized, and gaseous NaCl formed. Examination of the vapor composition shows that the vapor of the ionic drop and gaseous NaCl are composed of neutral species, the most abundant of which, ranging from simple NaCl monomers (ion pairs) to nonlinear polymers, (Na(n)Cl(n))(n=2-4). The enthalpies of sublimation, vaporization, and dissociation of the different vapor species are found to be in reasonable agreement with available experimental data. The decrease of the enthalpy of vaporization of the vapor species, with the radius of the drop decrease, accounts for a larger fraction of trimers and tetramers than that inferred from experiments. Further, the rhombic dimer is significantly more abundant than its linear isomer although the latter increases with the temperature. The present results suggest that both trimers and linear dimers may be important to explain the vapor pressure of molten NaCl at temperatures above 1500 K.

An evaporation model of multicomponent solution drops

NASA Astrophysics Data System (ADS)

Sartori, Silvana; Liñán, Amable; Lasheras, Juan C.

2010-11-01

Solutions of polymers are widely used in the pharmaceutical industry as tablets coatings. These allow controlling the rate at which the drug is delivered, taste or appearance. The coating is performed by spraying and drying the tablets at moderate temperatures. The wetting of the coating solution on the pill's surface depends on the droplet Webber and Re numbers, angle of impact and on the rheological properties of the droplet. We present a model for the evaporation of multicomponent solutions droplets in a hot air environment with temperatures substantially lower than the boiling temperature of the solvent. As the liquid vaporizes from the surface the fluid in the drop increases in concentration, until reaching its saturation point. After saturation, precipitation occurs uniformly within the drop. As the surface regresses, a compacting front formed by the precipitate at its maximum packing density advances into the drop, while the solute continues precipitating uniformly. This porous shell grows fast due to the double effect of surface regression and precipitation. The evaporation rate is determined by the rates at which heat is transported to the droplet surface and at which liquid vapor diffuses away from it. When the drop is fully compacted, the evaporation is drastically reduced.

Effect of flow rate and temperature on transmembrane blood pressure drop in an extracorporeal artificial lung.

PubMed

Park, M; Costa, E L V; Maciel, A T; Barbosa, E V S; Hirota, A S; Schettino, G de P; Azevedo, L C P

2014-11-01

Transmembrane pressure drop reflects the resistance of an artificial lung system to blood transit. Decreased resistance (low transmembrane pressure drop) enhances blood flow through the oxygenator, thereby, enhancing gas exchange efficiency. This study is part of a previous one where we observed the behaviour and the modulation of blood pressure drop during the passage of blood through artificial lung membranes. Before and after the induction of multi-organ dysfunction, the animals were instrumented and analysed for venous-venous extracorporeal membrane oxygenation, using a pre-defined sequence of blood flows. Blood flow and revolutions per minute (RPM) of the centrifugal pump varied in a linear fashion. At a blood flow of 5.5 L/min, pre- and post-pump blood pressures reached -120 and 450 mmHg, respectively. Transmembrane pressures showed a significant spread, particularly at blood flows above 2 L/min; over the entire range of blood flow rates, there was a positive association of pressure drop with blood flow (0.005 mmHg/mL/minute of blood flow) and a negative association of pressure drop with temperature (-4.828 mmHg/(°Celsius). These associations were similar when blood flows of below and above 2000 mL/minute were examined. During its passage through the extracorporeal system, blood is exposed to pressure variations from -120 to 450 mmHg. At high blood flows (above 2 L/min), the drop in transmembrane pressure becomes unpredictable and highly variable. Over the entire range of blood flows investigated (0-5500 mL/min), the drop in transmembrane pressure was positively associated with blood flow and negatively associated with body temperature. © The Author(s) 2014.

Design and performance prediction of solar adsorption cooling for mobile vaccine refrigerator

NASA Astrophysics Data System (ADS)

Djubaedah, Euis; Taufan, Andi; Ratnasari, Nadhira; Fahrizal, Adjie; Hamidi, Qayyum; Nasruddin

2017-03-01

Adsorption cooling is a process that uses a drop-in pressure caused by the adsorption of adsorbate by adsorbent. Adsorption process creates a pressure drop which can bring down the temperature to the intended condition. This approach can be used in vaccine transportation as the vaccines need to be stored at low temperatures (2°C to 8°C for preserving vaccines). The pressure decrease can be obtained by adsorption water in zeolites and can also produce the temperature drop in the main chamber. The adsorption process of water will decrease until reaching saturation condition. Heat is needed to keep the system continuous as it starts a desorption process. From the simulation using MATLAB, it is found that the mobile vaccine refrigerator can reach the temperature of 2°C in 180 seconds with the amount of cooling power generated is up to 1530 W. The insulation can hold the allowable temperature range inside the vaccine cabin for 15.6795 hours.

Association between the location of transposed ovary and ovarian function in patients with uterine cervical cancer treated with (postoperative or primary) pelvic radiotherapy.

PubMed

Hwang, Jong Ha; Yoo, Heon Jong; Park, Sae Hyun; Lim, Myong Cheol; Seo, Sang-Soo; Kang, Sokbom; Kim, Joo-Young; Park, Sang-Yoon

2012-06-01

To evaluate the effectiveness of ovarian transposition procedures in preserving ovarian function in relation to the location of the transposed ovaries in patients who underwent surgery with or without pelvic radiotherapy. Retrospective. Uterine cancer center. A total of 53 patients with cervical cancer who underwent ovarian transposition between November 2002 and November 2010. Ovarian transposition to the paracolic gutters with or without radical hysterectomy and lymph node dissection. Preservation of ovarian function, which was assessed by patient's symptoms and serum FSH level. Lateral ovarian transposition was performed in 53 patients. Based on receiver operator characteristic curve analysis, optimum cutoff value of location more than 1.5 cm above the iliac crest was significantly associated with preservation of ovarian function after treatment (area under receiver operator characteristic curve: 0.757, 95% confidence interval [CI]: 0.572-0.943). In univariate analysis, higher location of transposed ovary more than 1.5 cm from the iliac crest was the only independent factor for intact ovarian function (odds ratio 9.91, 95% CI: 1.75-56.3). Multivariate analysis confirmed that the location of transposed ovary (odds ratio 11.72, 95% CI 1.64-83.39) was the most important factor for intact ovarian function. Location of transposed ovary higher than 1.5 cm above the iliac crest is recommended to avoid ovarian failure after lateral ovarian transposition after primary or adjuvant pelvic radiotherapy in cervical cancer. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Lubrication model for evaporation of binary sessile drops

NASA Astrophysics Data System (ADS)

Williams, Adam; Sáenz, Pedro; Karapetsas, George; Matar, Omar; Sefiane, Khellil; Valluri, Prashant

2017-11-01

Evaporation of a binary mixture sessile drop from a solid substrate is a highly dynamic and complex process with flow driven both thermal and solutal Marangoni stresses. Experiments on ethanol/water drops have identified chaotic regimes on both the surface and interior of the droplet, while mixture composition has also been seen to govern drop wettability. Using a lubrication-type approach, we present a finite element model for the evaporation of an axisymmetric binary drop deposited on a heated substrate. We consider a thin drop with a moving contact line, taking also into account the commonly ignored effects of inertia which drives interfacial instability. We derive evolution equations for the film height, the temperature and the concentration field considering that the mixture comprises two ideally mixed volatile components with a surface tension linearly dependent on both temperature and concentration. The properties of the mixture such as viscosity also vary locally with concentration. We explore the parameter space to examine the resultant effects on wetting and evaporation where we find qualitative agreement with experiments in both these areas. This enables us to understand the nature of the instabilities that spontaneously emerge over the drop lifetime. EPSRC - EP/K00963X/1.

Identification and characterization of the first active endogenous transposable element in soybean

USDA-ARS?s Scientific Manuscript database

In soybean [Glycine max (L.) Merr.], W4 is one of the loci that control anthocyanin biosynthesis in flowers and hypocotyls. A putative transposable element was suggested to reside within or adjacent to this locus in the mutable T322 line resulting in the w4-m allele. We have shown that the W4 locu...

Moving from Science to Service: Transposing and Sustaining the Early Risers Prevention Program in a Community Service System

ERIC Educational Resources Information Center

Bloomquist, Michael L.; August, Gerald J.; Horowitz, Jason L.; Lee, Susanne S.; Jensen, Cheryl

2008-01-01

This paper summarizes an effort to transpose and sustain the evidence-based Early Risers "Skills for Success" conduct problems prevention program in a real world community service system. The Early Risers program had previously been implemented by a local agency within the context of research-based operations. In the current initiative,…

A Helitron-like Transposon Superfamily from Lepidoptera Disrupts (GAAA)n Microsatellites and is Responsible for Flanking Sequence Similarity within a Microsatellite Family

USDA-ARS?s Scientific Manuscript database

Transposable elements (TEs) are mobile DNA regions that alter host genome structure and gene expression. A novel 588 bp non-autonomous high copy number TE in the Ostrinia nubilalis genome has features in common with miniature inverted-repeat transposable elements (MITEs): high A+T content (62.3%),...

Distributional Analysis of the Transposed-Letter Neighborhood Effect on Naming Latency

ERIC Educational Resources Information Center

Johnson, Rebecca L.; Staub, Adrian; Fleri, Amanda M.

2012-01-01

Printed words that have a transposed-letter (TL) neighbor (e.g., angel has the TL neighbor angle) have been shown to be more difficult to process, in a range of paradigms, than words that do not have a TL neighbor. However, eye movement evidence suggests that this processing difficulty may occur on only a subset of trials. To investigate this…

Albinism due to transposable element insertion in fish.

PubMed

Koga, A; Hori, H

1997-12-01

The i locus of the medaka fish, Oryzias latipes, is responsible for tyrosinase expression, and several mutant alleles have been identified. The genotype i1/i1 exhibits a complete albino phenotype, having pale orange-red skin and red eyes. This mutant lacks in vivo tyrosinase activity. The genotype i4/i4, on the other hand, shows a quasi-albino phenotype with skin as bright as that of i1/i1 but with red-wine-colored eyes. At the light microscope level, reduced pigmentation is observed both in the skin and eyes of this mutant. The tyrosinase genes for the i1 and the i4 alleles were cloned and sequenced, and compared with that of the wild-type tyrosinase gene. The i1 allele was found to contain a 1.9-kb transposable element in the 1st exon, and the i4 allele was found to contain a 4.7-kb transposable element in the 5th exon. Both i1 and i4 are alleles that were found in a commercial breeding population. The insertion of a transposable element thus appears to constitute a natural cause of mutations that cause albinism in this organism.

Letter Position Coding Across Modalities: The Case of Braille Readers

PubMed Central

Perea, Manuel; García-Chamorro, Cristina; Martín-Suesta, Miguel; Gómez, Pablo

2012-01-01

Background The question of how the brain encodes letter position in written words has attracted increasing attention in recent years. A number of models have recently been proposed to accommodate the fact that transposed-letter stimuli like jugde or caniso are perceptually very close to their base words. Methodology Here we examined how letter position coding is attained in the tactile modality via Braille reading. The idea is that Braille word recognition may provide more serial processing than the visual modality, and this may produce differences in the input coding schemes employed to encode letters in written words. To that end, we conducted a lexical decision experiment with adult Braille readers in which the pseudowords were created by transposing/replacing two letters. Principal Findings We found a word-frequency effect for words. In addition, unlike parallel experiments in the visual modality, we failed to find any clear signs of transposed-letter confusability effects. This dissociation highlights the differences between modalities. Conclusions The present data argue against models of letter position coding that assume that transposed-letter effects (in the visual modality) occur at a relatively late, abstract locus. PMID:23071522

Correlations of catalytic combustor performance parameters

NASA Technical Reports Server (NTRS)

Bulzan, D. L.

1978-01-01

Correlations for combustion efficiency percentage drop and the minimum required adiabatic reaction temperature necessary to meet emissions goals of 13.6 g CO/kg fuel and 1.64 g HC/kg fuel are presented. Combustion efficiency was found to be a function of the cell density, cell circumference, reactor length, reference velocity, and adiabatic reaction temperature. The percentage pressure drop at an adiabatic reaction temperature of 1450 K was found to be proportional to the reference velocity to the 1.5 power and to the reactor length. It is inversely proportional to the pressure, cell hydraulic diameter, and fractional open area. The minimum required adiabatic reaction temperature was found to increase with reference velocity and decrease with cell circumference, cell density and reactor length. A catalyst factor was introduced into the correlations to account for differences between catalysts. Combustion efficiency, the percentage pressure drop, and the minimum required adiabatic reaction temperature were found to be a function of the catalyst factor. The data was from a 12 cm-diameter test rig with noble metal reactors using propane fuel at an inlet temperature of 800 K.

Theoretical and experimental emittance measurements for a thin liquid sheet flow

NASA Technical Reports Server (NTRS)

Englehart, Amy N.; Mcconley, Marc W.; Chubb, Donald L.

1995-01-01

Surface tension forces at the edges of a thin liquid (approximately 200 microns) sheet flow result in a triangularly shaped sheet. Such a geometry is ideal for an external flow radiator. Since the fluid must have very low vapor pressure, Dow Corning 705 silicone oil was used and the emittance of a flowing sheet of oil was determined by two methods. The emittance was derived as a function of the temperature drop between the top of the sheet and the coalescence point of the sheet, the sink temperature, the volumetric flow and the length of the sheet. the emittance for the oil was also calculated using an extinction coefficient determined from spectral transmittance data of the oil. The oil's emittance ranges from .67 to .87 depending on the sheet thickness and sheet temperature. The emittance derived from the temperature drop was slightly less than the emittance calculated from transmittance data. An investigation of temperature fluctuation upstream of the slit plate was also done. The fluctuations were determined to be negligible, not affecting the temperature drop which was due to radiation.

Visible and Thermal Imaging of Sea Ice and Open Water from Coast Guard Arctic Domain Awareness Flights

DTIC Science & Technology

2014-09-30

dropsondes, micro- aircraft), cloud top/base heights Arctic Ocean Surface Temperature project Steele Buoy drops for SLP , SST, SSS, & surface velocity...Colón & Vancas (NIC) Drop buoys for SLP , temperature and surface velocity Waves & Fetch in the MIZ Thompson SWIFTS buoys measuring wave energy...Expendable CTD, AXCP= Air Expendable Current Profiler, SLP = Sea Level atmospheric Pressure, SST= Seas Surface Temperature, A/C= aircraft, FSD= Floe Size Distribution, SIC=Sea Ice Concentration

Non-contact temperature measurement requirements

NASA Technical Reports Server (NTRS)

Higgins, D. B.; Witherow, W. K.

1989-01-01

The Marshall Space Flight Center is involved with levitation experiments for Spacelab, Space Station, and drop tube/tower operations. These experiments have temperature measurement requirements, that of course must be non-contact in nature. The experiment modules involved are the Acoustic Levitator Furnace (ALF), and the Modular Electromagnetic Levitator (MEL). User requirements of the ALF and drop tube are presented. The center also has temperature measurement needs that are not microgravity experiment oriented, but rather are related to the propulsion system for the STS. This requirement will also be discussed.

LINE-1 Elements in Structural Variation and Disease

PubMed Central

Beck, Christine R.; Garcia-Perez, José Luis; Badge, Richard M.; Moran, John V.

2014-01-01

The completion of the human genome reference sequence ushered in a new era for the study and discovery of human transposable elements. It now is undeniable that transposable elements, historically dismissed as junk DNA, have had an instrumental role in sculpting the structure and function of our genomes. In particular, long interspersed element-1 (LINE-1 or L1) and short interspersed elements (SINEs) continue to affect our genome, and their movement can lead to sporadic cases of disease. Here, we briefly review the types of transposable elements present in the human genome and their mechanisms of mobility. We next highlight how advances in DNA sequencing and genomic technologies have enabled the discovery of novel retrotransposons in individual genomes. Finally, we discuss how L1-mediated retrotransposition events impact human genomes. PMID:21801021

A Navier-Strokes Chimera Code on the Connection Machine CM-5: Design and Performance

NASA Technical Reports Server (NTRS)

Jespersen, Dennis C.; Levit, Creon; Kwak, Dochan (Technical Monitor)

1994-01-01

We have implemented a three-dimensional compressible Navier-Stokes code on the Connection Machine CM-5. The code is set up for implicit time-stepping on single or multiple structured grids. For multiple grids and geometrically complex problems, we follow the 'chimera' approach, where flow data on one zone is interpolated onto another in the region of overlap. We will describe our design philosophy and give some timing results for the current code. A parallel machine like the CM-5 is well-suited for finite-difference methods on structured grids. The regular pattern of connections of a structured mesh maps well onto the architecture of the machine. So the first design choice, finite differences on a structured mesh, is natural. We use centered differences in space, with added artificial dissipation terms. When numerically solving the Navier-Stokes equations, there are liable to be some mesh cells near a solid body that are small in at least one direction. This mesh cell geometry can impose a very severe CFL (Courant-Friedrichs-Lewy) condition on the time step for explicit time-stepping methods. Thus, though explicit time-stepping is well-suited to the architecture of the machine, we have adopted implicit time-stepping. We have further taken the approximate factorization approach. This creates the need to solve large banded linear systems and creates the first possible barrier to an efficient algorithm. To overcome this first possible barrier we have considered two options. The first is just to solve the banded linear systems with data spread over the whole machine, using whatever fast method is available. This option is adequate for solving scalar tridiagonal systems, but for scalar pentadiagonal or block tridiagonal systems it is somewhat slower than desired. The second option is to 'transpose' the flow and geometry variables as part of the time-stepping process: Start with x-lines of data in-processor. Form explicit terms in x, then transpose so y-lines of data are in-processor. Form explicit terms in y, then transpose so z-lines are in processor. Form explicit terms in z, then solve linear systems in the z-direction. Transpose to the y-direction, then solve linear systems in the y-direction. Finally transpose to the x direction and solve linear systems in the x-direction. This strategy avoids inter-processor communication when differencing and solving linear systems, but requires a large amount of communication when doing the transposes. The transpose method is more efficient than the non-transpose strategy when dealing with scalar pentadiagonal or block tridiagonal systems. For handling geometrically complex problems the chimera strategy was adopted. For multiple zone cases we compute on each zone sequentially (using the whole parallel machine), then send the chimera interpolation data to a distributed data structure (array) laid out over the whole machine. This information transfer implies an irregular communication pattern, and is the second possible barrier to an efficient algorithm. We have implemented these ideas on the CM-5 using CMF (Connection Machine Fortran), a data parallel language which combines elements of Fortran 90 and certain extensions, and which bears a strong similarity to High Performance Fortran. We make use of the Connection Machine Scientific Software Library (CMSSL) for the linear solver and array transpose operations.

Minos as a novel Tc1/mariner-type transposable element for functional genomic analysis in Aspergillus nidulans.

PubMed

Evangelinos, Minoas; Anagnostopoulos, Gerasimos; Karvela-Kalogeraki, Iliana; Stathopoulou, Panagiota M; Scazzocchio, Claudio; Diallinas, George

2015-08-01

Transposons constitute powerful genetic tools for gene inactivation, exon or promoter trapping and genome analyses. The Minos element from Drosophila hydei, a Tc1/mariner-like transposon, has proved as a very efficient tool for heterologous transposition in several metazoa. In filamentous fungi, only a handful of fungal-specific transposable elements have been exploited as genetic tools, with the impala Tc1/mariner element from Fusarium oxysporum being the most successful. Here, we developed a two-component transposition system to manipulate Minos transposition in Aspergillus nidulans (AnMinos). Our system allows direct selection of transposition events based on re-activation of niaD, a gene necessary for growth on nitrate as a nitrogen source. On average, among 10(8) conidiospores, we obtain up to ∼0.8×10(2) transposition events leading to the expected revertant phenotype (niaD(+)), while ∼16% of excision events lead to AnMinos loss. Characterized excision footprints consisted of the four terminal bases of the transposon flanked by the TA target duplication and led to no major DNA rearrangements. AnMinos transposition depends on the presence of its homologous transposase. Its frequency was not significantly affected by temperature, UV irradiation or the transcription status of the original integration locus (niaD). Importantly, transposition is dependent on nkuA, encoding an enzyme essential for non-homologous end joining of DNA in double-strand break repair. AnMinos proved to be an efficient tool for functional analysis as it seems to transpose in different genomic loci positions in all chromosomes, including a high proportion of integration events within or close to genes. We have used Minos to obtain morphological and toxic analogue resistant mutants. Interestingly, among morphological mutants some seem to be due to Minos-elicited over-expression of specific genes, rather than gene inactivation. Copyright © 2015 Elsevier Inc. All rights reserved.

Do we understand the temperature profile of air-water interface?

NASA Astrophysics Data System (ADS)

Solcerova, A.; van Emmerik, T. H. M.; Uittenbogaard, R.; van de Ven, F. H. M.; Van De Giesen, N.

2017-12-01

Lakes and reservoirs exchange energy with the atmosphere through long-wave radiation and turbulent heat fluxes. Calculation of those fluxes often depend on the surface temperature. Several recent studies used high resolution Distributed Temperature Sensing (DTS) to measure the temperature of air-water interface. We present results of three of such studies conducted on three different locations with three different climates (Ghana, Israel, The Netherland). Measurements from all presented studies show a distinct temperature drop close to the water surface during daytime. We provide several possible explanations for existence of such deviation of temperature, and discuss the plausibility of each. Explaining the measured temperature drop is crucial for a better understanding of the energy balance of lake surface, and estimation of the surface energy balance.

Preview Effects of Plausibility and Character Order in Reading Chinese Transposed Words: Evidence from Eye Movements

ERIC Educational Resources Information Center

Yang, Jinmian

2013-01-01

The current paper examined the role of plausibility information in the parafovea for Chinese readers by using two-character transposed words (in which the order of the component characters is reversed but are still words). In two eye-tracking experiments, readers received a preview of a target word that was (1) identical to the target word, (2) a…

The endogenous transposable element Tgm9 is suitable for functional analyses of soybean genes and generating novel mutants for genetic improvement of soybean

USDA-ARS?s Scientific Manuscript database

In soybean, variegated flowers can be caused by somatic excision of the CACTA-type transposable element Tgm9 from intron 2 of the DFR2 gene encoding dihydroflavonol-4-reductase in the anthocyanin pigment biosynthetic pathway. DFR2 has been mapped to the W4 locus where the allele containing the elem...

Electromagnetic fluctuations for anisotropic media and the generalized Kirchhoff's law

NASA Technical Reports Server (NTRS)

Yueh, Simon H.; Kwok, R.

1993-01-01

In this paper the polarimetric emission parameters for anisotropic media are derived using the generalized Kirchhoff's law for media with a uniform temperature and the fluctuation-dissipation theory for media with a temperature profile. Both finite-size objects and half-space media are considered. When the object has a uniform temperature across its body, the Kirchhoff's law, based on the condition of energy conservation in thermal equilibrium is generalized to obtain the emission parameters of an anisotropic medium, which can be interpreted as the absorptivity or the absorption cross section of the complementary object with a permittivity that is the transpose of the original object. When the medium has a nonuniform temperature distribution, the fluctuation-dissipation theory is applied for deriving the covariances between vector components of the thermal currents and, consequently, the covariances of the polarizations of electric fields radiated by the thermal currents. To verify the formulas derived from the fluctuation-dissipation theory, we let the temperature of the object be a constant and show that the results reduce to those obtained from the generalized Kirchhoff's law.

Secondary pool boiling effects

NASA Astrophysics Data System (ADS)

Kruse, C.; Tsubaki, A.; Zuhlke, C.; Anderson, T.; Alexander, D.; Gogos, G.; Ndao, S.

2016-02-01

A pool boiling phenomenon referred to as secondary boiling effects is discussed. Based on the experimental trends, a mechanism is proposed that identifies the parameters that lead to this phenomenon. Secondary boiling effects refer to a distinct decrease in the wall superheat temperature near the critical heat flux due to a significant increase in the heat transfer coefficient. Recent pool boiling heat transfer experiments using femtosecond laser processed Inconel, stainless steel, and copper multiscale surfaces consistently displayed secondary boiling effects, which were found to be a result of both temperature drop along the microstructures and nucleation characteristic length scales. The temperature drop is a function of microstructure height and thermal conductivity. An increased microstructure height and a decreased thermal conductivity result in a significant temperature drop along the microstructures. This temperature drop becomes more pronounced at higher heat fluxes and along with the right nucleation characteristic length scales results in a change of the boiling dynamics. Nucleation spreads from the bottom of the microstructure valleys to the top of the microstructures, resulting in a decreased surface superheat with an increasing heat flux. This decrease in the wall superheat at higher heat fluxes is reflected by a "hook back" of the traditional boiling curve and is thus referred to as secondary boiling effects. In addition, a boiling hysteresis during increasing and decreasing heat flux develops due to the secondary boiling effects. This hysteresis further validates the existence of secondary boiling effects.

Football helmet drop tests on different fields using an instrumented Hybrid III head.

PubMed

Viano, David C; Withnall, Chris; Wonnacott, Michael

2012-01-01

An instrumented Hybrid III head was placed in a Schutt ION 4D football helmet and dropped on different turfs to study field types and temperature on head responses. The head was dropped 0.91 and 1.83 m giving impacts of 4.2 and 6.0 m/s on nine different football fields (natural, Astroplay, Fieldturf, or Gameday turfs) at turf temperatures of -2.7 to 23.9 °C. Six repeat tests were conducted for each surface at 0.3 m (1') intervals. The Hybrid III was instrumented with triaxial accelerometers to determine head responses for the different playing surfaces. For the 0.91-m drops, peak head acceleration varied from 63.3 to 117.1 g and HIC(15) from 195 to 478 with the different playing surfaces. The lowest response was with Astroplay, followed by the engineered natural turf. Gameday and Fieldturf involved higher responses. The differences between surfaces decreased in the 1.83 m tests. The cold weather testing involved higher accelerations, HIC(15) and delta V for each surface. The helmet drop test used in this study provides a simple and convenient means of evaluating the compliance and energy absorption of football playing surfaces. The type and temperature of the playing surface influence head responses.

Thermosolutal Marangoni convection short-time regimes - Proposals for drop tower experiments and real time computer simulation

NASA Astrophysics Data System (ADS)

Polezhaev, V. I.; Ermakov, M. K.

1992-12-01

Results are presented of a parametrical study of flow patterns, heat transfer, and time scales of thermosolutal Marangoni convection in a cavity with temperature and solutal gradients along the free surface and adiabatic bottom for the case of zero gravity. Nusselt number, concentration difference across the cavity, and flow/temperature fields for the different regimes are presented; they show the possibility to use Drop Tower 'Bremen' for measuring the developed secondary flow and heat/mass transfer due to thermosolutal Marangoni convection as well as the possibility to analyze and plan the drop tower for such experiments using the COMGA PC-based system.

Modeling Thermal Contact Resistance

NASA Technical Reports Server (NTRS)

Kittel, Peter; Sperans, Joel (Technical Monitor)

1994-01-01

One difficulty in using cryocoolers is making good thermal contact between the cooler and the instrument being cooled. The connection is often made through a bolted joint. The temperature drop associated with this joint has been the subject of many experimental and theoretical studies. The low temperature behavior of dry joints have shown some anomalous dependence on the surface condition of the mating parts. There is also some doubts on how well one can extrapolate from the test samples to predicting the performance of a real system. Both finite element and analytic models of a simple contact system have been developed. The model assumes (a) the contact is dry (contact limited to a small portion of the total available area and the spaces in-between the actual contact patches are perfect insulators), (b) contacts are clean (conductivity of the actual contact is the same as the bulk), (c) small temperature gradients (the bulk conductance may be assumed to be temperature independent), (d) the absolute temperature is low (thermal radiation effects are ignored), and (e) the dimensions of the nominal contact area are small compared to the thickness of the bulk material (the contact effects are localized near the contact). The models show that in the limit of actual contact area much less than the nominal area (a much less than A), that the excess temperature drop due to a single point of contact scales as a(exp -1/2). This disturbance only extends a distance approx. A(exp 1/2) into the bulk material. A group of identical contacts will result in an excess temperature drop that scales as n(exp -1/2), where n is the number of contacts and n dot a is constant. This implies that flat rough surfaces will have a lower excess temperature drop than flat polished surfaces.

Improved Control of Charging Voltage for Li-Ion Battery

NASA Technical Reports Server (NTRS)

Timmerman, Paul; Bugga, Ratnakumar

2006-01-01

The protocol for charging a lithium-ion battery would be modified, according to a proposal, to compensate for the internal voltage drop (charging current internal resistance of the battery). The essence of the modification is to provide for measurement of the internal voltage drop and to increase the terminal-voltage setting by the amount of the internal voltage drop. Ordinarily, a lithium-ion battery is charged at constant current until its terminal voltage attains a set value equal to the nominal full-charge potential. The set value is chosen carefully so as not to exceed the lithium-plating potential, because plated lithium in metallic form constitutes a hazard. When the battery is charged at low temperature, the internal voltage drop is considerable because the electrical conductivity of the battery electrolyte is low at low temperature. Charging the battery at high current at any temperature also gives rise to a high internal voltage drop. In some cases, the internal voltage drop can be as high as 1 volt per cell. Because the voltage available for charging is less than the terminal voltage by the amount of the internal voltage drop, the battery is not fully charged (see figure), even when the terminal voltage reaches the set value. In the modified protocol, the charging current would be periodically interrupted so that the zero-current battery-terminal voltage indicative of the state of charge could be measured. The terminal voltage would also be measured at full charging current. The difference between the full-current and zero-current voltages would equal the internal voltage drop. The set value of terminal voltage would then be increased beyond the nominal full-charge potential by the amount of the internal voltage drop. This adjustment would be performed repeatedly, in real time, so that the voltage setting would track variations in the internal voltage drop to afford full charge without risk of lithium plating. If the charging current and voltage settings were controlled by a computer, then this method of charge control could readily be implemented in software.

Development of Bone-Conducted Ultrasonic Hearing Aid for the Profoundly Deaf: Assessments of the Modulation Type with Regard to Intelligibility and Sound Quality

NASA Astrophysics Data System (ADS)

Nakagawa, Seiji; Fujiyuki, Chika; Kagomiya, Takayuki

2012-07-01

Bone-conducted ultrasound (BCU) is perceived even by the profoundly sensorineural deaf. A novel hearing aid using the perception of amplitude-modulated BCU (BCU hearing aid: BCUHA) has been developed; however, further improvements are needed, especially in terms of articulation and sound quality. In this study, the intelligibility and sound quality of BCU speech with several types of amplitude modulation [double-sideband with transmitted carrier (DSB-TC), double-sideband with suppressed carrier (DSB-SC), and transposed modulation] were evaluated. The results showed that DSB-TC and transposed speech were more intelligible than DSB-SC speech, and transposed speech was closer than the other types of BCU speech to air-conducted speech in terms of sound quality. These results provide useful information for further development of the BCUHA.

A systematic review of randomised controlled trials of the effects of warmed irrigation fluid on core body temperature during endoscopic surgeries.

PubMed

Jin, Yinghui; Tian, Jinhui; Sun, Mei; Yang, Kehu

2011-02-01

The purpose of this systematic review was to establish whether warmed irrigation fluid temperature could decrease the drop of body temperature and incidence of shivering and hypothermia. Irrigation fluid, which is used in large quantities during endoscopic surgeries at room temperature, is considered to be associated with hypothermia and shivering. It remains controversial whether using warmed irrigation fluid to replace room-temperature irrigation fluid will decrease the drop of core body temperature and the occurrence of hypothermia. A comprehensive search (computerised database searches, footnote chasing, citation chasing) was undertaken to identify all the randomised controlled trials that explored temperature of irrigation fluid in endoscopic surgery. An approach involving meta-analysis was used. We searched PubMed, EMBASE, Cochrane Library, SCI, China academic journals full-text databases, Chinese Biomedical Literature Database, Chinese scientific journals databases and Chinese Medical Association Journals for trials that meet the inclusion criteria. Study quality was assessed using standards recommended by Cochrane Library Handbook 5.0.1. Disagreement was resolved by consensus. Thirteen randomised controlled trials including 686 patients were identified. The results showed that room-temperature irrigation fluid caused a greater drop of core body temperature in patients, compared to warmed irrigation fluid (p < 0.00001; I(2) = 85%). The occurrence of shivering [odds ratio (OR) 5.13, 95% CI: 2.95-10.19, p < 0.00001; I(2) = 0%] and hypothermia (OR 22.01, 95% CI: 2.03-197.08, p = 0.01; I(2) = 64%) in the groups having warmed irrigation fluid were lower than the group of studies having room-temperature fluid. In endoscopic surgeries, irrigation fluid is recommended to be warmed to decrease the drop of core body temperature and the risk of perioperative shivering and hypothermia. Warming irrigating fluid should be considered standard practice in all endoscopic surgeries. © 2011 Blackwell Publishing Ltd.

Extremely cold events and sudden air temperature drops during winter season in the Czech Republic

NASA Astrophysics Data System (ADS)

Crhová, Lenka; Valeriánová, Anna; Holtanová, Eva; Müller, Miloslav; Kašpar, Marek; Stříž, Martin

2014-05-01

Today a great attention is turned to analysis of extreme weather events and frequency of their occurrence under changing climate. In most cases, these studies are focused on extremely warm events in summer season. However, extremely low values of air temperature during winter can have serious impacts on many sectors as well (e.g. power engineering, transportation, industry, agriculture, human health). Therefore, in present contribution we focus on extremely and abnormally cold air temperature events in winter season in the Czech Republic. Besides the seasonal extremes of minimum air temperature determined from station data, the standardized data with removed annual cycle are used as well. Distribution of extremely cold events over the season and the temporal evolution of frequency of occurrence during the period 1961-2010 are analyzed. Furthermore, the connection of cold events with extreme sudden temperature drops is studied. The extreme air temperature events and events of extreme sudden temperature drop are assessed using the Weather Extremity Index, which evaluates the extremity (based on return periods) and spatial extent of the meteorological extreme event of interest. The generalized extreme value distribution parameters are used to estimate return periods of daily temperature values. The work has been supported by the grant P209/11/1990 funded by the Czech Science Foundation.

Analysis of metal tolerance in Rhizobium leguminosarum strains isolated from an ultramafic soil.

PubMed

Rubio-Sanz, Laura; Brito, Belén; Palacios, Jose

2018-02-01

Natural habitats containing high amounts of heavy metals provide a valuable source of bacteria adapted to deal with metal toxicity. A functional analysis of the population of legume endosymbiotic bacteria in an ultramafic soil was undertaken by studying a collection of Rhizobium leguminosarum bv viciae (Rlv) isolates obtained using pea as trap plant. One of the isolates, Rlv UPM1137, was selected on the basis of its higher tolerance to nickel and cobalt and presence of inducible mechanisms for such tolerance. A random transposon mutagenesis of Rlv UPM1137 allowed the generation of 14 transposant derivatives with increased nickel sensitivity; five of these transposants were also more sensitive to cobalt. Sequencing of the insertion sites revealed that one of the transposants (D2250) was affected in a gene homologous to the cation diffusion facilitator gene dmeF first identified in the metal-resistant bacterium Cupriavidus metallidurans CH34. The symbiotic performance of D2250 and two other transposants bearing single transposon insertions was unaffected under high-metal conditions, suggesting that, in contrast to previous observations in other Rlv strain, metal tolerance in UPM1137 under symbiotic conditions might be supported by functional redundancy between several mechanisms. © FEMS 2018. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Satellite DNA and Transposable Elements in Seabuckthorn (Hippophae rhamnoides), a Dioecious Plant with Small Y and Large X Chromosomes

PubMed Central

Puterova, Janka; Razumova, Olga; Martinek, Tomas; Alexandrov, Oleg; Divashuk, Mikhail; Kubat, Zdenek; Hobza, Roman; Karlov, Gennady

2017-01-01

Seabuckthorn (Hippophae rhamnoides) is a dioecious shrub commonly used in the pharmaceutical, cosmetic, and environmental industry as a source of oil, minerals and vitamins. In this study, we analyzed the transposable elements and satellites in its genome. We carried out Illumina DNA sequencing and reconstructed the main repetitive DNA sequences. For data analysis, we developed a new bioinformatics approach for advanced satellite DNA analysis and showed that about 25% of the genome consists of satellite DNA and about 24% is formed of transposable elements, dominated by Ty3/Gypsy and Ty1/Copia LTR retrotransposons. FISH mapping revealed X chromosome-accumulated, Y chromosome-specific or both sex chromosomes-accumulated satellites but most satellites were found on autosomes. Transposable elements were located mostly in the subtelomeres of all chromosomes. The 5S rDNA and 45S rDNA were localized on one autosomal locus each. Although we demonstrated the small size of the Y chromosome of the seabuckthorn and accumulated satellite DNA there, we were unable to estimate the age and extent of the Y chromosome degeneration. Analysis of dioecious relatives such as Shepherdia would shed more light on the evolution of these sex chromosomes. PMID:28057732

Substituted-letter and transposed-letter effects in a masked priming paradigm with French developing readers and dyslexics.

PubMed

Lété, Bernard; Fayol, Michel

2013-01-01

The aim of the study was to undertake a behavioral investigation of the development of automatic orthographic processing during reading acquisition in French. Following Castles and colleagues' 2007 study (Journal of Experimental Child Psychology, 97, 165-182) and their lexical tuning hypothesis framework, substituted-letter and transposed-letter primes were used in a masked priming paradigm with third graders, fifth graders, adults, and phonological dyslexics matched on reading level with the third graders. No priming effect was found in third graders. In adults, only a transposed-letter priming effect was found; there was no substituted-letter priming effect. Finally, fifth graders and dyslexics showed both substituted-letter and transposed-letter priming effects. Priming effects between the two groups were of the same magnitude after response time (RT) z-score transformation. Taken together, our results show that the pattern of priming effects found by Castles and colleagues in English normal readers emerges later in French normal readers. In other words, language orthographies seem to constrain the tuning of the orthographic system, with an opaque orthography producing faster tuning of orthographic processing than more transparent orthographies because of the high level of reliance on phonological decoding while learning to read. Copyright © 2012 Elsevier Inc. All rights reserved.

Letter-transposition effects are not universal: The impact of transposing letters in Hebrew

PubMed Central

Velan, Hadas; Frost, Ram

2009-01-01

We examined the effects of letter transposition in Hebrew in three masked-priming experiments. Hebrew, like English has an alphabetic orthography where sequential and contiguous letter strings represent phonemes. However, being a Semitic language it has a non-concatenated morphology that is based on root derivations. Experiment 1 showed that transposed-letter (TL) root primes inhibited responses to targets derived from the non-transposed root letters, and that this inhibition was unrelated to relative root frequency. Experiment 2 replicated this result and showed that if the transposed letters of the root created a nonsense-root that had no lexical representation, then no inhibition and no facilitation were obtained. Finally, Experiment 3 demonstrated that in contrast to English, French, or Spanish, TL nonword primes did not facilitate recognition of targets, and when the root letters embedded in them consisted of a legal root morpheme, they produced inhibition. These results suggest that lexical space in alphabetic orthographies may be structured very differently in different languages if their morphological structure diverges qualitatively. In Hebrew, lexical space is organized according to root families rather than simple orthographic structure, so that all words derived from the same root are interconnected or clustered together, independent of overall orthographic similarity. PMID:20161017

Non-Contact Temperature Requirements (NCTM) for drop and bubble physics

NASA Technical Reports Server (NTRS)

Hmelo, Anthony B.; Wang, Taylor G.

1989-01-01

Many of the materials research experiments to be conducted in the Space Processing program require a non-contaminating method of manipulating and controlling weightless molten materials. In these experiments, the melt is positioned and formed within a container without physically contacting the container's wall. An acoustic method, which was developed by Professor Taylor G. Wang before coming to Vanderbilt University from the Jet Propulsion Laboratory, has demonstrated the capability of positioning and manipulating room temperature samples. This was accomplished in an earth-based laboratory with a zero-gravity environment of short duration. However, many important facets of high temperature containerless processing technology have not been established yet, nor can they be established from the room temperature studies, because the details of the interaction between an acoustic field an a molten sample are largely unknown. Drop dynamics, bubble dynamics, coalescence behavior of drops and bubbles, electromagnetic and acoustic levitation methods applied to molten metals, and thermal streaming are among the topics discussed.

Water Drop Evaporation on Mushroom-like Superhydrophobic Surfaces: Temperature Effects.

PubMed

do Nascimento, Rodney Marcelo; Cottin-Bizonne, Cécile; Pirat, Christophe; Ramos, Stella M M

2016-03-01

We report on experiments of drop evaporation on heated superhydrophobic surfaces decorated with micrometer-sized mushroom-like pillars. We analyze the influence of two parameters on the evaporation dynamics: the solid-liquid fraction and the substrate temperature, ranging between 30 and 80 °C. In the different configurations investigated, the drop evaporation appears to be controlled by the contact line dynamics (pinned or moving). The experimental results show that (i) in the pinned regime, the depinning angles increase with decreasing contact fraction and the substrate heating promotes the contact line depinning and (ii) in the moving regime, the droplet motion is described by periodic stick-slip events and contact-angle oscillations. These features are highly smoothed at the highest temperatures, with two possible mechanisms suggested to explain such a behavior, a reduction in the elasticity of the triple line and a decrease in the depinning energy barriers. For all surfaces, the observed remarkable stability of the "fakir" state to the temperature is attributed to the re-entrant micropillar curvature that prevents surface imbibition.

Suppression of Mg propagation into subsequent layers grown by MOCVD

NASA Astrophysics Data System (ADS)

Agarwal, Anchal; Tahhan, Maher; Mates, Tom; Keller, Stacia; Mishra, Umesh

2017-01-01

Low temperature (LT) flow modulation epitaxy (FME) or "pulsed" growth was successfully used to prevent magnesium from Metalorganic Chemical Vapor Deposition (MOCVD) grown p-GaN:Mg layers riding into subsequently deposited n-type layers. Mg concentration in the subsequent layers was lowered from ˜1 × 1018 cm-3 for a medium temperature growth at 950 °C to ˜1 × 1016 cm-3 for a low temperature growth at 700 °C via FME. The slope of the Mg concentration drop in the 700 °C FME sample was 20 nm/dec—the lowest ever demonstrated by MOCVD. For growth on Mg implanted GaN layers, the drop for a medium temperature regrowth at 950 °C was ˜10 nm/dec compared to >120 nm/dec for a high temperature regrowth at 1150 °C. This drop-rate obtained at 950 °C or lower was maintained even when the growth temperature in the following layers was raised to 1150 °C. A controlled silicon doping series using LT FME was also demonstrated with the lowest and highest achieved doping levels being 5 × 1016 cm-3 and 6 × 1019 cm-3, respectively.

Large charged drop levitation against gravity

NASA Technical Reports Server (NTRS)

Rhim, Won-Kyu; Chung, Sang Kun; Hyson, Michael T.; Trinh, Eugene H.; Elleman, Daniel D.

1987-01-01

A hybrid electrostatic-acoustic levitator that can levitate and manipulate a large liquid drop in one gravity is presented. To the authors' knowledge, this is the first time such large drops (up to 4 mm in diameter in the case of water) have been levitated against 1-gravity. This makes possible, for the first time, many new experiments both in space and in ground-based laboratories, such as 1)supercooling and superheating, 2) containerless crystal growth from various salt solutions or melts, 3) drop dynamics of oscillating or rotating liquid drops, 4) drop evaporation and Rayleigh bursting, and 5) containerless material processing in space. The digital control system, liquid drop launch process, principles of electrode design, and design of a multipurpose room temperature levitation chamber are described. Preliminary results that demonstrate drop oscillation and rotation, and crystal growth from supersaturated salt solutions are presented.

The structure of evaporating and combusting sprays: Measurements and predictions

NASA Technical Reports Server (NTRS)

Shuen, J. S.; Solomon, A. S. P.; Faeth, G. M.

1984-01-01

An apparatus developed, to allow observations of monodisperse sprays, consists of a methane-fueled turbulent jet diffusion flame with monodisperse methanol drops injected at the burner exit. Mean and fluctuating-phase velocities, drop sizes, drop-mass fluxes and mean-gas temperatures were measured. Initial drop diameters of 100 and 180 microns are being considered in order to vary drop penetration in the flow and effects of turbulent dispersion. Baseline tests of the burner flame with no drops present were also conducted. Calibration tests, needed to establish methods for predicting drop transport, involve drops supported in the post-flame region of a flat-flame burner operated at various mixture ratios. Spray models which are being evaluated include: (1) locally homogeneous flow (LFH) analysis, (2) deterministic separated flow (DSF) analysis and (3) stochastic separated flow (SSF) analysis.

The transition from frictional sliding to shear melting in laboratory experiments and the implications for scale dependent earthquake source properties

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Lockner, D. A.; Kilgore, B. D.; Moore, D. E.

2011-12-01

Localized slip during earthquakes, e.g., at 1 m/s for a few seconds, should produce enough thermal energy to melt rock or pressurize pore fluid and drastically reduce fault strength (Sibson, Nature Phys. Sci., 1973. Sibson, Geophys. J. R. Astr. Soc., 1975). Expected changes in earthquake source properties for events with large enough temperature change to induce melting or fluid pressurization include an increase in stress drop, a possible increase in low frequency content of the radiated energy and an increase in the ratio of radiated energy to seismic moment. Such changes with increasing moment, while expected, are not observed seismologically and the role of thermal weakening during large earthquakes remains unknown. To investigate the effect of the onset of thermal weakening on earthquake source properties such as stress drop, slip velocity, weakening distance, and apparent stress, we have conducted stick-slip experiments at confining pressures between 50 and 400 MPa on initially bare rock surfaces of Westerly granite (Lockner et al., Eos Trans. Am. Geophys. Un. T23A-2245, 2010). These conditions span a transition from frictional sliding, producing dry comminuted fault gouge and fractional stress drops at lower confining pressure, to shear induced melting with complete stress drop at the highest pressures. The confining pressure, axial stress and displacement, are measured as in standard faulting tests. Temperature is monitored with a thermocouple ~2.5 mm from the fault. Rapid motions of the fault are inferred from independent recordings of the acceleration and velocity of the loading piston using an accelerometer and a laser Doppler vibrometer. Slip velocity, and event duration increase with stress drop. Stress drops vary from less than 10 to greater than 400 MPa. Durations are between 0.1 and 0.5 ms and average sliding velocities range from <1 to > 10 m/s. Total stress drop is associated with slip and shear stress sufficient to increase the entire shear zone temperature to the melting point of feldspar, but melt is also found in samples subjected to smaller stress drops, suggesting heating to somewhat lower temperature. Stress and slip constrain the total energy; the temperature measurements constrain the energy associated with frictional heating and the heat of fusion, while the velocity measurements allow an estimate of the radiated energy. Using these constraints and models of shear-induced melting we examine changes in event source properties across the transition to shear melting.

Meteorological effects of the solar eclipse of 20 March 2015: analysis of UK Met Office automatic weather station data and comparison with automatic weather station data from the Faroes and Iceland

PubMed Central

Penman, John; Jónsson, Trausti; Bigg, Grant R.; Björnsson, Halldór; Sjúrðarson, Sølvi; Hansen, Mads A.; Cappelen, John; Bryant, Robert G.

2016-01-01

Here, we analyse high-frequency (1 min) surface air temperature, mean sea-level pressure (MSLP), wind speed and direction and cloud-cover data acquired during the solar eclipse of 20 March 2015 from 76 UK Met Office weather stations, and compare the results with those from 30 weather stations in the Faroe Islands and 148 stations in Iceland. There was a statistically significant mean UK temperature drop of 0.83±0.63°C, which occurred over 39 min on average, and the minimum temperature lagged the peak of the eclipse by about 10 min. For a subset of 14 (16) relatively clear (cloudy) stations, the mean temperature drop was 0.91±0.78 (0.31±0.40)°C but the mean temperature drops for relatively calm and windy stations were almost identical. Mean wind speed dropped significantly by 9% on average during the first half of the eclipse. There was no discernible effect of the eclipse on the wind-direction or MSLP time series, and therefore we can discount any localized eclipse cyclone effect over Britain during this event. Similar changes in air temperature and wind speed are observed for Iceland, where conditions were generally clearer, but here too there was no evidence of an eclipse cyclone; in the Faroes, there was a much more muted meteorological signature. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550769

Thermocapillary migration and interactions of bubbles and drops

NASA Technical Reports Server (NTRS)

Subramanian, R. Shankar; Balasubramaniam, R.

1994-01-01

Results from ground-based theoretical and experimental research on the motion of bubbles and drops in a temperature gradient are described and a brief account is given of plans for a flight experiment scheduled in 1994.

Spatially resolved measurements of ion heating during impulsive reconnection in the Madison Symmetric Torus.

PubMed

Gangadhara, S; Craig, D; Ennis, D A; Hartog, D J Den; Fiksel, G; Prager, S C

2007-02-16

The impurity ion temperature evolution has been measured during three types of impulsive reconnection events in the Madison Symmetric Torus reversed field pinch. During an edge reconnection event, the drop in stored magnetic energy is small and ion heating is observed to be limited to the outer half of the plasma. Conversely, during a global reconnection event the drop in stored magnetic energy is large, and significant heating is observed at all radii. For both kinds of events, the drop in magnetic energy is sufficient to explain the increase in ion thermal energy. However, not all types of reconnection lead to ion heating. During a core reconnection event, both the stored magnetic energy and impurity ion temperature remain constant. The results suggest that a drop in magnetic energy is required for ions to be heated during reconnection, and that when this occurs heating is localized near the reconnection layer.

Bleaching and recovery of a phototrophic bioeroding sponge

NASA Astrophysics Data System (ADS)

Marlow, Joseph; Davy, Simon K.; Shaffer, Megan; Haris, Abdul; Bell, James J.

2018-06-01

In the Wakatobi region of Indonesia, a prolonged period of elevated water temperature in 2016 caused extensive coral bleaching and mortality. Unusually, bleaching was also observed in the bioeroding sponge Cliona aff. viridis, with affected sponges expelling 99% of their Symbiodinium. Bleaching surveys of C. aff. viridis were conducted 6 weeks apart, coinciding with a 0.8 °C drop in water temperature. Over this period, bleaching prevalence dropped from 73.9% (± 9.9 SE) to 25.7% (± 5.8 SE), and bleaching severity dropped from 25.95% (± 4.5 SE) to 11.54% (± 1.9 SE) of sponge tissue. Over the same period, monitored bleached sponges showed an 81% drop in bleaching severity, but also a 13% reduction in overall sponge size. Our results show that while the clionaid- Symbiodinium relationship is susceptible to break down under thermal stress, rapid recovery can occur, although incurring some partial host mortality.

Star-shaped oscillations of Leidenfrost drops

NASA Astrophysics Data System (ADS)

Ma, Xiaolei; Liétor-Santos, Juan-José; Burton, Justin C.

2017-03-01

We experimentally investigate the self-sustained, star-shaped oscillations of Leidenfrost drops. The drops levitate on a cushion of evaporated vapor over a heated, curved surface. We observe modes with n =2 -13 lobes around the drop periphery. We find that the wavelength of the oscillations depends only on the capillary length of the liquid and is independent of the drop radius and substrate temperature. However, the number of observed modes depends sensitively on the liquid viscosity. The dominant frequency of pressure variations in the vapor layer is approximately twice the drop oscillation frequency, consistent with a parametric forcing mechanism. Our results show that the star-shaped oscillations are driven by capillary waves of a characteristic wavelength beneath the drop and that the waves are generated by a large shear stress at the liquid-vapor interface.

Spec Rekindled-A Simple Torque Correction Mechanics for Transposed Teeth in Conjunction with Pre-adjusted Edgewise Appliance System.

PubMed

Singh, Harpreet; Maurya, Raj Kumar; Thakkar, Surbhi

2016-12-01

Complete transposition of teeth is a rather rare phenomenon. After correction of transposed and malaligned lateral incisor and canine, attainment of appropriate individual antagonistic tooth torque is indispensable, which many orthodontists consider to be a herculean task. Here, a novel method is proposed which demonstrates the use of Spec reverse torquing auxillary as an effective adjunctive aid in conjunction with pre-adjusted edgewise brackets.

Colonization of heterochromatic genes by transposable elements in Drosophila.

PubMed

Dimitri, Patrizio; Junakovic, Nikolaj; Arcà, Bruno

2003-04-01

As a further step toward understanding transposable element-host genome interactions, we investigated the molecular anatomy of introns from five heterochromatic and 22 euchromatic protein-coding genes of Drosophila melanogaster. A total of 79 kb of intronic sequences from heterochromatic genes and 355 kb of intronic sequences from euchromatic genes have been used in Blast searches against Drosophila transposable elements (TEs). The results show that TE-homologous sequences belonging to 19 different families represent about 50% of intronic DNA from heterochromatic genes. In contrast, only 0.1% of the euchromatic intron DNA exhibits homology to known TEs. Intraspecific and interspecific size polymorphisms of introns were found, which are likely to be associated with changes in TE-related sequences. Together, the enrichment in TEs and the apparent dynamic state of heterochromatic introns suggest that TEs contribute significantly to the evolution of genes located in heterochromatin.

[Active miniature inverted-repeat transposable elements transposon in plants: a review].

PubMed

Hu, Bingjie; Zhou, Mingbing

2018-02-25

Miniature inverted-repeat transposable elements transposon is a special transposon that could transpose by "cut-paste" mechanism, which is one of characteristics of DNA transposons. Otherwise, the copy number of MITEs is very high, which is one of characteristics of RNA transposons. Many MITE families have been reported, but little about active MITEs. We summarize recent advances in studying active MITEs. Most the MITEs belong to the Tourist-like family, such as mPing, mGing, PhTourist1, Tmi1 and PhTst-3. Additionally, DTstu1 and MITE-39 belong to Stowaway-like family, and AhMITEs1 belongs to Mutator-like family. Moreover, we summarize the structure (terminal inverse repeats and target site duplications), copy number, evolution pattern and transposition characteristics of these active MITEs, to provide the foundation for the identification of other active MITEs and subsequent research on MITE transposition and amplification mechanism.

Partial transpose of random quantum states: Exact formulas and meanders

NASA Astrophysics Data System (ADS)

Fukuda, Motohisa; Śniady, Piotr

2013-04-01

We investigate the asymptotic behavior of the empirical eigenvalues distribution of the partial transpose of a random quantum state. The limiting distribution was previously investigated via Wishart random matrices indirectly (by approximating the matrix of trace 1 by the Wishart matrix of random trace) and shown to be the semicircular distribution or the free difference of two free Poisson distributions, depending on how dimensions of the concerned spaces grow. Our use of Wishart matrices gives exact combinatorial formulas for the moments of the partial transpose of the random state. We find three natural asymptotic regimes in terms of geodesics on the permutation groups. Two of them correspond to the above two cases; the third one turns out to be a new matrix model for the meander polynomials. Moreover, we prove the convergence to the semicircular distribution together with its extreme eigenvalues under weaker assumptions, and show large deviation bound for the latter.

Read count-based method for high-throughput allelic genotyping of transposable elements and structural variants.

PubMed

Kuhn, Alexandre; Ong, Yao Min; Quake, Stephen R; Burkholder, William F

2015-07-08

Like other structural variants, transposable element insertions can be highly polymorphic across individuals. Their functional impact, however, remains poorly understood. Current genome-wide approaches for genotyping insertion-site polymorphisms based on targeted or whole-genome sequencing remain very expensive and can lack accuracy, hence new large-scale genotyping methods are needed. We describe a high-throughput method for genotyping transposable element insertions and other types of structural variants that can be assayed by breakpoint PCR. The method relies on next-generation sequencing of multiplex, site-specific PCR amplification products and read count-based genotype calls. We show that this method is flexible, efficient (it does not require rounds of optimization), cost-effective and highly accurate. This method can benefit a wide range of applications from the routine genotyping of animal and plant populations to the functional study of structural variants in humans.

Transposition of the maize transposable element Ac in barley (Hordeum vulgare L.).

PubMed

Scholz, S; Lörz, H; Lütticke, S

2001-01-01

Transposition of the maize autonomous element Ac (Activator) was investigated in barley (Hordeum vulgare L.) with the aim of developing a transposon tagging system for the latter. The Ac element was introduced into meristematic tissue of barley by microprojectile bombardment. Transposon activity was then examined in the resulting transgenic plants. Multiple excision events were detected in leaf tissue of all plant lines. The mobile elements generated empty donor sites with small DNA sequence alterations, similar to those found in maize. Reintegration of Ac at independent genomic loci in somatic tissue was demonstrated by isolation of new element-flanking regions by AIMS-PCR (amplification of insertion-mutagenized sites). In addition, transmission of transposed Ac elements to progeny plants was confirmed. The results indicate that the introduced Ac element is able to transpose in barley. This is a first step towards the establishment of a transposon tagging system in this economically important crop.

Fundamental study of transpiration cooling. [pressure drop and heat transfer data from porous metals

NASA Technical Reports Server (NTRS)

Koh, J. C. Y.; Dutton, J. L.; Benson, B. A.

1973-01-01

Isothermal and non-isothermal pressure drop data and heat transfer data generated on porous 304L stainless steel wire forms, sintered spherical stainless steel powder, and sintered spherical OFHC copper powder are reported and correlated. Pressure drop data was collected over a temperature range from 500 R to 2000 R and heat transfer data collected over a heat flux range from 5 to 15 BTU/in2/sec. It was found that flow data could be correlated independently of transpirant temperature and type (i.e., H2, N2). It was also found that no simple relation between heat transfer coefficient and specimen porosity was obtainable.

The Superheat Phenomenon in the Combustion of Magnesium Particles

NASA Technical Reports Server (NTRS)

Shafirovich, E. IA.; Goldshleger, U. I.

1992-01-01

Magnesium is known to be a likely fuel for engines that could work in the CO2 atmospheres of Mars and Venus. The present paper reports temperature measurements of magnesium samples during combustion in CO2. The burning sample temperature increases with the decrease in the initial size. The temperature of the 1-mm samples is 300-400 K higher than the boiling point of magnesium. The stability of the superheated drop is explained by the presence of a porous shell on the surface. An attempt has been made to describe vaporization on the superheated drop by the Knudsen-Langmuir equation. During combustion at high-pressure fragment ejection of the flame is observed in high-speed motion pictures. This phenomenon is shown to be connected with the drop superheat. The repeated fracture of the outer shell formed in the flame ensures the complete burnout of metal particles at high pressure.

Atomization, drop size, and penetration for cross-stream water injection at high-altitude reentry conditions with application to the RAM C-1 and C-3 flights

NASA Technical Reports Server (NTRS)

Gooderum, P. B.; Bushnell, D. M.

1972-01-01

Atomization, drop size, and penetration data are presented for cross stream water injection at conditions simulating high altitude reentry (low Weber number, high static temperature, high Knudsen number, and low static pressure). These results are applied to the RAM C-1 and C-3 flights. Two primary breakup modes are considered, vapor pressure or flashing and aerodynamic atomization. Results are given for breakup boundaries and mean drop size for each of these atomization mechanisms. Both standard and flight orifice geometries are investigated. The data were obtained in both a static environment and in conventional aerodynamic facilities at Mach numbers of 4.5 and 8. The high temperature aspects of reentry were simulated in a Mach 5.5 cyanogen-oxygen tunnel with total temperature of 4500 K.

On the relationship between tectonic plates and thermal mantle plume morphology

NASA Technical Reports Server (NTRS)

Lenardic, A.; Kaula, W. M.

1993-01-01

Models incorporating plate-like behavior, i.e., near uniform surface velocity and deformation concentrated at plate boundaries, into a convective system, heated by a mix of internal and basal heating and allowing for temperature dependent viscosity, were constructed and compared to similar models not possessing plate-like behavior. The simplified numerical models are used to explore how plate-like behavior in a convective system can effect the lower boundary layer from which thermal plumes form. A principal conclusion is that plate-like behavior can significantly increase the temperature drop across the lower thermal boundary layer. This temperature drop affects the morphology of plumes by determining the viscosity drop across the boundary layer. Model results suggest that plumes on planets possessing plate-like behavior, e.g., the Earth, may differ in morphologic type from plumes on planets not possessing plate-like behavior, e.g., Venus and Mars.

Bauschinger effect in haynes 230 alloy: Influence of strain rate and temperature

NASA Astrophysics Data System (ADS)

Thakur, Aniruddha; Vecchio, Kenneth S.; Nemat-Nasser, Sia

1996-07-01

Quasistatic and dynamic Bauschinger behavior in HAYNES 230 alloy is examined. At low strain rate (10-3/s), the as- received 230 alloy does not show a drop in flow stress, i.e., no Bauschinger effect is displayed. At high strain rate (103/s), a drop in flow stress of 240 MPa was observed upon stress reversal. In contrast, the precipitation- strengthened condition exhibited a Bauschinger effect in both low and high strain rate stress-reversal experiments. The magnitude of the Bauschinger effect was found to increase with increasing strain rate, forward strain, and decreasing temperature. The substructure evolution accompanying the forward loading cycles was investigated by transmission electron microscopy and is related to the back stresses that developed. The increased Bauschinger stress drop observed at high strain rate and/or low temperature was correlated to an increased degree of planar slip under these conditions.

The evaporation of a drop of mercury

NASA Astrophysics Data System (ADS)

Winter, Thomas G.

2003-08-01

The evaporative rates of two drops of mercury at room temperature are determined experimentally and theoretically. The resulting mercury vapor levels are estimated and measured, compared with the OSHA permissible exposure limit, and found to be small by comparison.

Reticulo-rumen temperature as a predictor of calving time in primiparous and parous Holstein females.

PubMed

Costa, J B G; Ahola, J K; Weller, Z D; Peel, R K; Whittier, J C; Barcellos, J O J

2016-06-01

The objective of this research was to define and analyze drops in reticulo-rumen temperature (Trr) as an indicator of calving time in Holstein females. Data were collected from 111 primiparous and 150 parous Holstein females between November 2012 and March 2013. Between -15 and -5 d relative to anticipated calving date, each female received an orally administered temperature sensing reticulo-rumen bolus that collected temperatures hourly. Daily mean Trr was calculated from d -5 to 0 relative to using all Trr values (A-Trr) or only Trr values ≥37.7°C (W-Trr) not altered by water intake. To identify a Trr drop, 2 methodologies for computing the baseline temperature were used. Generalized linear models (GLM) were used to estimate the probability of calving within the next 12 or 24 h for primiparous, parous, and all females, based on the size of the Trr drop. For all GLM, a large drop in Trr corresponded with a large estimated probability of calving. The predictive power of the GLM was assessed using receiver-operating characteristic (ROC) curves. The ROC curve analyses showed that all models, regardless of methodology in calculation of the baseline or tested category (primiparous or parous), were able to predict calving; however, area under the ROC curve values, an indication of prediction quality, were greater for methods predicting calving within 24 h. Further comparisons between GLM for primiparous and parous, and using baseline 1 and 2, provide insight on the differences in predictive performance. Based on the GLM, Trr drops of 0.2, 0.3, and 0.4°C were identified as useful indicators of parturition and further analyzed using sensitivity, specificity, and diagnostic odds ratios. Based on sensitivity, specificity, and diagnostic odds ratios, the best indicator of calving was an average Trr drop ≥0.2°C, regardless of methodology used to compute the baseline or category of animal evaluated. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Thermally driven oscillations and wave motion of a liquid drop

NASA Technical Reports Server (NTRS)

Baumeister, K. J.; Hendricks, R. C.; Schoessow, G. J.

1977-01-01

In the state of Leidenfrost boiling, liquid drops are observed to vibrate in a variety of modal patterns. Theories are presented which predict the frequency of oscillation and show that the observed modal patterns of drops correspond to the minimum energy oscillatory excitation state. High-speed photographic techniques were used to record these motions and substantiate the theories. An incipient temperature was also found for water drops in film boiling below which free oscillations do not exist. In addition to these oscillations, photographic sequences are presented which show that wave motion can exist along the circumference of the drop. Following the study of free oscillations, the system was mounted on a shaker table and the drop subjected to a range of forced frequencies and accelerations.

Thermally Driven Oscillations and Wave Motion of a Liquid Drop

NASA Technical Reports Server (NTRS)

Baumeister, K. J.; Hendricks, R. C.; Schoessow, G. J.

1977-01-01

In the state of Leidenfrost boiling, liquid drops are observed to vibrate in a variety of modal patterns. Theories are presented which predict the frequency of oscillation and show that the observed model patterns of drops correspond to the minimum energy oscillatory excitation state. High-speed photographic techniques were used to record these motions and substantiate the theories. An incipient temperature was also found for water drops in film boiling below which free oscillations do not exist. In addition to these oscillations, photographic sequences are presented which show that wave motion can exist along the circumference of the drop. Following the study of free oscillations, the system was mounted on a shaker table and the drop subjected to a range of forced frequencies and accelerations.

Drop-on-Demand System for Manufacturing of Melt-based Solid Oral Dosage: Effect of Critical Process Parameters on Product Quality.

PubMed

Içten, Elçin; Giridhar, Arun; Nagy, Zoltan K; Reklaitis, Gintaras V

2016-04-01

The features of a drop-on-demand-based system developed for the manufacture of melt-based pharmaceuticals have been previously reported. In this paper, a supervisory control system, which is designed to ensure reproducible production of high quality of melt-based solid oral dosages, is presented. This control system enables the production of individual dosage forms with the desired critical quality attributes: amount of active ingredient and drug morphology by monitoring and controlling critical process parameters, such as drop size and product and process temperatures. The effects of these process parameters on the final product quality are investigated, and the properties of the produced dosage forms characterized using various techniques, such as Raman spectroscopy, optical microscopy, and dissolution testing. A crystallization temperature control strategy, including controlled temperature cycles, is presented to tailor the crystallization behavior of drug deposits and to achieve consistent drug morphology. This control strategy can be used to achieve the desired bioavailability of the drug by mitigating variations in the dissolution profiles. The supervisor control strategy enables the application of the drop-on-demand system to the production of individualized dosage required for personalized drug regimens.

Spec Rekindled-A Simple Torque Correction Mechanics for Transposed Teeth in Conjunction with Pre-adjusted Edgewise Appliance System

PubMed Central

Singh, Harpreet; Thakkar, Surbhi

2016-01-01

Complete transposition of teeth is a rather rare phenomenon. After correction of transposed and malaligned lateral incisor and canine, attainment of appropriate individual antagonistic tooth torque is indispensable, which many orthodontists consider to be a herculean task. Here, a novel method is proposed which demonstrates the use of Spec reverse torquing auxillary as an effective adjunctive aid in conjunction with pre-adjusted edgewise brackets. PMID:28209017

Satellite DNA and Transposable Elements in Seabuckthorn (Hippophae rhamnoides), a Dioecious Plant with Small Y and Large X Chromosomes.

PubMed

Puterova, Janka; Razumova, Olga; Martinek, Tomas; Alexandrov, Oleg; Divashuk, Mikhail; Kubat, Zdenek; Hobza, Roman; Karlov, Gennady; Kejnovsky, Eduard

2017-01-01

Seabuckthorn (Hippophae rhamnoides) is a dioecious shrub commonly used in the pharmaceutical, cosmetic, and environmental industry as a source of oil, minerals and vitamins. In this study, we analyzed the transposable elements and satellites in its genome. We carried out Illumina DNA sequencing and reconstructed the main repetitive DNA sequences. For data analysis, we developed a new bioinformatics approach for advanced satellite DNA analysis and showed that about 25% of the genome consists of satellite DNA and about 24% is formed of transposable elements, dominated by Ty3/Gypsy and Ty1/Copia LTR retrotransposons. FISH mapping revealed X chromosome-accumulated, Y chromosome-specific or both sex chromosomes-accumulated satellites but most satellites were found on autosomes. Transposable elements were located mostly in the subtelomeres of all chromosomes. The 5S rDNA and 45S rDNA were localized on one autosomal locus each. Although we demonstrated the small size of the Y chromosome of the seabuckthorn and accumulated satellite DNA there, we were unable to estimate the age and extent of the Y chromosome degeneration. Analysis of dioecious relatives such as Shepherdia would shed more light on the evolution of these sex chromosomes. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

DNA methylation dynamics during early plant life.

PubMed

Bouyer, Daniel; Kramdi, Amira; Kassam, Mohamed; Heese, Maren; Schnittger, Arp; Roudier, François; Colot, Vincent

2017-09-25

Cytosine methylation is crucial for gene regulation and silencing of transposable elements in mammals and plants. While this epigenetic mark is extensively reprogrammed in the germline and early embryos of mammals, the extent to which DNA methylation is reset between generations in plants remains largely unknown. Using Arabidopsis as a model, we uncovered distinct DNA methylation dynamics over transposable element sequences during the early stages of plant development. Specifically, transposable elements and their relics show invariably high methylation at CG sites but increasing methylation at CHG and CHH sites. This non-CG methylation culminates in mature embryos, where it reaches saturation for a large fraction of methylated CHH sites, compared to the typical 10-20% methylation level observed in seedlings or adult plants. Moreover, the increase in CHH methylation during embryogenesis matches the hypomethylated state in the early endosperm. Finally, we show that interfering with the embryo-to-seedling transition results in the persistence of high CHH methylation levels after germination, specifically over sequences that are targeted by the RNA-directed DNA methylation (RdDM) machinery. Our findings indicate the absence of extensive resetting of DNA methylation patterns during early plant life and point instead to an important role of RdDM in reinforcing DNA methylation of transposable element sequences in every cell of the mature embryo. Furthermore, we provide evidence that this elevated RdDM activity is a specific property of embryogenesis.

Genetic and DNA sequence analysis of the kanamycin resistance transposon Tn903.

PubMed Central

Grindley, N D; Joyce, C M

1980-01-01

The kanamycin resistance transposon Tn903 consists of a unique region of about 1000 base pairs bounded by a pair of 1050-base-pair inverted repeat sequences. Each repeat contains two Pvu II endonuclease cleavage sites separated by 520 base pairs. We have constructed derivatives of Tn903 in which this 520-base-pair fragment is deleted from one or both repeats. Those derivatives that lack both 520-base-pair fragments cannot transpose, whereas those that lack just one remain transposition proficient. One such transposable derivative, Tn903 delta I, has been selected for further study. We have determined the sequence of the intact inverted repeat. The 18 base pairs at each end are identical and inverted relative to one another, a structure characteristic of insertion sequences. Additional experiments indicate that a single inverted repeat from Tn903 can, in fact, transpose; we propose that this element be called IS903. To correlate the DNA sequence with genetic activities, we have created mutations by inserting a 10-base-pair DNA fragment at several sites within the intact repeat of Tn903 delta 1, and we have examined the effect of such insertions on transposability. The results suggest that IS903 encodes a 307-amino-acid polypeptide (a "transposase") that is absolutely required for transposition of IS903 or Tn903. Images PMID:6261245

Heat loss and drag of spherical drop tube samples

NASA Technical Reports Server (NTRS)

Wallace, D. B.

1982-01-01

Analysis techniques for three aspects of the performance of the NASA/MSFC 32 meter drop tube are considered. Heat loss through the support wire in a pendant drop sample, temperature history of a drop falling through the drop tube when the tube is filled with helium gas at various pressures, and drag and resulting g-levels experienced by a drop falling through the tube when the tube is filled with helium gas at various pressures are addressed. The developed methods apply to systems with sufficiently small Knudsen numbers for which continuum theory may be applied. Sample results are presented, using niobium drops, to indicate the magnitudes of the effects. Helium gas at one atmosphere pressure can approximately double the amount of possible undercooling but it results in an apparent gravity levels of up to 0.1 g.

An unusual metallic behavior in a Ag4SSe single crystal

NASA Astrophysics Data System (ADS)

Matteppanavar, Shidaling; Bui, Nguyen Hai An; van Smaalen, Sander; Thamizhavel, A.; Ramakrishnan, S.

2018-04-01

We report the magnetic susceptibility, resistivity and heat capacity measurements on high quality single crystalline tetra silver sulphoselenide (Ag4SSe). The magnetic susceptibility and resistivity measurements show anomalies around 260 K. The large diamagnetic drop with hysteresis at the transition implies a first order transition. Such a diamagnetic drop cannot be ascribed to the formation of charge density wave (CDW) since the temperature dependence of the resistivity shows no upturn at this transition. Infact the resistivity is decreasing with decreasing temperature, indicating a metallic behavior. However, unlike normal metals, the resistivity is almost temperature independent in the temperature range from 4-180 K. Usually, when one observes a diamagnetic transition, it is assumed to be due to a drop in the density of states at the Fermi level which leads to the decrease in the Pauli paramagnetic susceptibility. Such a decrease in the density of states often results in an increase in resistivity unless mobility of the charge carriers changes significantly. Hence, we believe that in Ag4SSe, the structural transition causes an unusual Fermi surface reconstruction which in turn leads to a strange metallic behavior at low temperatures.

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

Trianti, Nuri, E-mail: nuri.trianti@gmail.com; Nurjanah,; Su’ud, Zaki

Thermalhydraulic of reactor core is the thermal study on fluids within the core reactor, i.e. analysis of the thermal energy transfer process produced by fission reaction from fuel to the reactor coolant. This study include of coolant temperature and reactor power density distribution. The purposes of this analysis in the design of nuclear power plant are to calculate the coolant temperature distribution and the chimney height so natural circulation could be occurred. This study was used boiling water reactor (BWR) with cylinder type reactor core. Several reactor core properties such as linear power density, mass flow rate, coolant density andmore » inlet temperature has been took into account to obtain distribution of coolant density, flow rate and pressure drop. The results of calculation are as follows. Thermal hydraulic calculations provide the uniform pressure drop of 1.1 bar for each channels. The optimum mass flow rate to obtain the uniform pressure drop is 217g/s. Furthermore, from the calculation it could be known that outlet temperature is 288°C which is the saturated fluid’s temperature within the system. The optimum chimney height for natural circulation within the system is 14.88 m.« less

The structure of dilute combusting sprays

NASA Technical Reports Server (NTRS)

Shuen, J. S.; Solomon, A. S. P.; Faeth, F. M.

1985-01-01

An experimental and theoretical study of drop processes in a turbulent flame is described. The experiments involved a monodisperse (105 and 180 micro m initial diameter) stream of methanol drops injected at the base of a turbulent methane-fueled diffusion flame burning in still air. The following measurements were made: mean and fluctuating phase velocities, mean drop number flux, drop-size distributions and mean gas-phase temperatures. Measurements were compared with predictions of two separated flow models: (1) deterministic separated flow, where drop-turbulence interactions are ignored; and (2) stochastic separated flow, where drop-turbulence interactions are considered using random-walk computations. The stochastic separated flow analysis yielded best agreement with measurements, since it provides for turbulent dispersion of drops which was important for present test conditions (and probably for most combusting sprays as well). Distinguishing the presence or absence of envelope flames around the drops, however, was relatively unimportant for present test conditions, since the drops spent most of their lifetime in fuel-rich regions of the flow where this distinction is irrelevant.

Calorimetric determination of thermal parameters for the Li/BrCl in SOCl2 (BCX) chemistry

NASA Technical Reports Server (NTRS)

Darcy, Eric C.; Kalu, Eric E.; White, Ralph E.

1990-01-01

The heat capacity of a Li-BCX DD-cell was found to be dependent on its state of charge by drop calorimetry measurements. The method of drop calorimetry involves measuring the energy (joules) gained or lost from a sample that is transferred from a bath at temperature A to one at temperature B. The thermoneutral potential is defined as the cell potential where the cell electrochemical reactions are neither exothermic nor endothermic. A Hart scientific calorimeter system, Model No. S77XX, designed for heat conduction calorimetry and drop calorimetry was used. Calorimetric analysis yielded a thermoneutral potential of 4.14 volts and a cell heat capacity dependent on the state of charge.

Cache and energy efficient algorithms for Nussinov's RNA Folding.

PubMed

Zhao, Chunchun; Sahni, Sartaj

2017-12-06

An RNA folding/RNA secondary structure prediction algorithm determines the non-nested/pseudoknot-free structure by maximizing the number of complementary base pairs and minimizing the energy. Several implementations of Nussinov's classical RNA folding algorithm have been proposed. Our focus is to obtain run time and energy efficiency by reducing the number of cache misses. Three cache-efficient algorithms, ByRow, ByRowSegment and ByBox, for Nussinov's RNA folding are developed. Using a simple LRU cache model, we show that the Classical algorithm of Nussinov has the highest number of cache misses followed by the algorithms Transpose (Li et al.), ByRow, ByRowSegment, and ByBox (in this order). Extensive experiments conducted on four computational platforms-Xeon E5, AMD Athlon 64 X2, Intel I7 and PowerPC A2-using two programming languages-C and Java-show that our cache efficient algorithms are also efficient in terms of run time and energy. Our benchmarking shows that, depending on the computational platform and programming language, either ByRow or ByBox give best run time and energy performance. The C version of these algorithms reduce run time by as much as 97.2% and energy consumption by as much as 88.8% relative to Classical and by as much as 56.3% and 57.8% relative to Transpose. The Java versions reduce run time by as much as 98.3% relative to Classical and by as much as 75.2% relative to Transpose. Transpose achieves run time and energy efficiency at the expense of memory as it takes twice the memory required by Classical. The memory required by ByRow, ByRowSegment, and ByBox is the same as that of Classical. As a result, using the same amount of memory, the algorithms proposed by us can solve problems up to 40% larger than those solvable by Transpose.

A specific insertion of a solo-LTR characterizes the Y-chromosome of Bryonia dioica (Cucurbitaceae).

PubMed

Oyama, Ryan K; Silber, Martina V; Renner, Susanne S

2010-06-14

Relatively few species of flowering plants are dioecious and even fewer are known to have sex chromosomes. Current theory posits that homomorphic sex chromosomes, such as found in Bryonia dioica (Cucurbitaceae), offer insight into the early stages in the evolution of sex chromosomes from autosomes. Little is known about these early steps, but an accumulation of transposable element sequences has been observed on the Y-chromosomes of some species with heteromorphic sex chromosomes. Recombination, by which transposable elements are removed, is suppressed on at least part of the emerging Y-chromosome, and this may explain the correlation between the emergence of sex chromosomes and transposable element enrichment. We sequenced 2321 bp of the Y-chromosome in Bryonia dioica that flank a male-linked marker, BdY1, reported previously. Within this region, which should be suppressed for recombination, we observed a solo-LTR nested in a Copia-like transposable element. We also found other, presumably paralogous, solo-LTRs in a consensus sequence of the underlying Copia-like transposable element. Given that solo-LTRs arise via recombination events, it is noteworthy that we find one in a genomic region where recombination should be suppressed. Although the solo-LTR could have arisen before recombination was suppressed, creating the male-linked marker BdY1, our previous study on B. dioica suggested that BdY1 may not lie in the recombination-suppressed region of the Y-chromosome in all populations. Presence of a solo-LTR near BdY1 therefore fits with the observed correlation between retrotransposon accumulation and the suppression of recombination early in the evolution of sex chromosomes. These findings further suggest that the homomorphic sex chromosomes of B. dioica, the first organism for which genetic XY sex-determination was inferred, are evolutionarily young and offer reference information for comparative studies of other plant sex chromosomes.

Feminist theorizing as 'transposed autobiography'.

PubMed

Hoogland, Renée C

2007-01-01

This piece considers personal investments endemic in academic writing, more specifically, in Lesbian Studies. Taking Elizabeth Bowen's phrase, "transposed autobiography," as a starting-point, the author briefly discusses the development of lesbian/straight feminist debates, and continues to explore the relative absence of lesbianism in current feminist and queer theorizing. Three 'moments' serve to explain the casting aside of lesbian desire: the subsidence of lesbian/straight feminist debates, the prevalence of 'race'/ethnicity in critical theorizing and the emergence of post-theoretical trends of thought.

Transposable elements as a molecular evolutionary force

NASA Technical Reports Server (NTRS)

Fedoroff, N. V.

1999-01-01

This essay addresses the paradoxes of the complex and highly redundant genomes. The central theses developed are that: (1) the distinctive feature of complex genomes is the existence of epigenetic mechanisms that permit extremely high levels of both tandem and dispersed redundancy; (2) the special contribution of transposable elements is to modularize the genome; and (3) the labilizing forces of recombination and transposition are just barely contained, giving a dynamic genetic system of ever increasing complexity that verges on the chaotic.

Age specific effect of MK-801 on hypoxic body temperature regulation in rats.

PubMed

Baig, Mirza Shafiulla; Joseph, Vincent

2008-02-01

Hypoxic exposure produces a consistent decrease of rectal temperature (Tb), which is recognized as a potent protective response. While some of the neural mechanisms underlying this response have recently been described, it remains poorly known how these mechanisms evolve during post-natal development. We recently reported that in rat pups NMDA glutamate receptor limits Tb drop upon hypoxic exposure, an effect that has not been reported by others in adult rats. Accordingly, we tested the hypothesis that the implication of NMDA receptors on temperature control during hypoxic exposure evolves during development. To this aim, we evaluated the hypoxic (30 min - 12% O(2)) responses of Tb, metabolic rate, and ventilation in rats after injection of vehicle, or the NMDA receptor antagonist MK-801, at different ages (post-natal days 4, 10, 20 and 2-3 month-old - P4, P10, P20 and P60). MK-801 amplified the magnitude of the hypoxic-induced Tb drop in P4, P10 and P20 rats, but this effect was not apparent in adults. In P20 rats MK-801 tripled the hypoxic induced Tb drop, which was 0.5 degrees C in control and 1.4 degrees C in treated rats (p<0.0001). This effect was specific to temperature regulation, and was not accompanied by similar changes of other recorded parameters. MK-801 induced a significant decrease of the hypoxic ventilatory response in adults only. We conclude that NMDA glutamate receptor acts as a counter-regulatory factor that limits the hypoxic-induced drop of rectal temperature during post-natal development in rats.

Transient effects in ice nucleation of a water drop impacting onto a cold substrate

NASA Astrophysics Data System (ADS)

Schremb, Markus; Roisman, Ilia V.; Tropea, Cameron

2017-02-01

The impact of water drops onto a solid surface at subfreezing temperatures has been experimentally studied. Drop nucleation has been observed using a high-speed video system. The statistics of nucleation allows the estimation of the average number of nucleation sites per unit area of the wetted part of the substrate. We have discovered that the nucleation rate in the impacting drop is not constant. The observed significant increase of the nucleation rate at small times after impact t <50 ms can be explained by the generation of nanobubbles at early times of drop impact. These bubbles serve as additional nucleation sites and enhance the nucleation rate.

Transient effects in ice nucleation of a water drop impacting onto a cold substrate.

PubMed

Schremb, Markus; Roisman, Ilia V; Tropea, Cameron

2017-02-01

The impact of water drops onto a solid surface at subfreezing temperatures has been experimentally studied. Drop nucleation has been observed using a high-speed video system. The statistics of nucleation allows the estimation of the average number of nucleation sites per unit area of the wetted part of the substrate. We have discovered that the nucleation rate in the impacting drop is not constant. The observed significant increase of the nucleation rate at small times after impact t<50 ms can be explained by the generation of nanobubbles at early times of drop impact. These bubbles serve as additional nucleation sites and enhance the nucleation rate.

Tn5401, a new class II transposable element from Bacillus thuringiensis.

PubMed Central

Baum, J A

1994-01-01

A new class II (Tn3-like) transposable element, designated Tn5401, was recovered from a sporulation-deficient variant of Bacillus thuringiensis subsp. morrisoni EG2158 following its insertion into a recombinant plasmid. Sequence analysis of the insert revealed a 4,837-bp transposon with two large open reading frames, in the same orientation, encoding proteins of 36 kDa (306 residues) and 116 kDa (1,005 residues) and 53-bp terminal inverted repeats. The deduced amino acid sequence for the 36-kDa protein shows 24% sequence identity with the TnpI recombinase of the B. thuringiensis transposon Tn4430, a member of the phage integrase family of site-specific recombinases. The deduced amino acid sequence for the 116-kDa protein shows 42% sequence identity with the transposase of Tn3 but only 28% identity with the TnpA transposase of Tn4430. Two small open reading frames of unknown function, designated orf1 (85 residues) and orf2 (74 residues), were also identified. Southern blot analysis indicated that Tn5401, in contrast to Tn4430, is not commonly found among different subspecies of B. thuringiensis and is not typically associated with known insecticidal crystal protein genes. Transposition was studied with B. thuringiensis by using plasmid pEG922, a temperature-sensitive shuttle vector containing Tn5401. Tn5401 transposed to both chromosomal and plasmid target sites but displayed an apparent preference for plasmid sites. Transposition was replicative and resulted in the generation of a 5-bp duplication at the target site. Transcriptional start sites within Tn5401 were mapped by primer extension analysis. Two promoters, designated PL and PR, direct the transcription of orf1-orf2 and tnpI-tnpA, respectively, and are negatively regulated by TnpI. Sequence comparison of the promoter regions of Tn5401 and Tn4430 suggests that the conserved sequence element ATGTCCRCTAAY mediates TnpI binding and cointegrate resolution. The same element is contained within the 53-bp terminal inverted repeats, thus accounting for their unusual lengths and suggesting an additional role for TnpI in regulating Tn5401 transposition. Images PMID:7514590

Heat transfer and pressure drop measurements in an air/molten salt direct-contact heat exchanger

NASA Astrophysics Data System (ADS)

Bohn, Mark S.

1988-11-01

This paper presents a comparison of experimental data with a recently published model of heat exchange in irrigated packed beds. Heat transfer and pressure drop were measured in a 150 mm (ID) column with a 610 mm bed of metal Pall rings. Molten nitrate salt and preheated air were the working fluids with a salt inlet temperature of approximately 440 C and air inlet temperatures of approximately 230 C. A comparison between the experimental data and the heat transfer model is made on the basis of heat transfer from the salt. For the range of air and salt flow rates tested, 0.3 to 1.2 kg/sq m/s air flow and 6 to 18 kg/sq m/s salt flow, the data agree with the model within 22 percent standard deviation. In addition, a model for the column pressure drop was validated, agreeing with the experimental data within 18 percent standard deviation over the range of column pressure drop from 40 to 1250 Pa/m.

The control effect of histamine on body temperature and respiratory function in IgE-dependent systemic anaphylaxis.

PubMed

Makabe-Kobayashi, Yoko; Hori, Yoshio; Adachi, Tetsuya; Ishigaki-Suzuki, Satsuki; Kikuchi, Yoshihiro; Kagaya, Yutaka; Shirato, Kunio; Nagy, András; Ujike, Azusa; Takai, Toshiyuki; Watanabe, Takehiko; Ohtsu, Hiroshi

2002-08-01

The systemic anaphylaxis reaction comprises various symptoms, including hypotension, changes in respiration pattern, and hypothermia. To elucidate the role of histamine in each of these symptoms, we induced the passive systemic anaphylaxis reaction in histidine decarboxylase gene knockout (HDC [-/-]) mice, which lack histamine. HDC(-/-) mice were generated by knocking out the HDC gene, which codes for the unique histamine-synthesizing enzyme. Twenty-four hours after the injection of IgE, HDC(+/+) and HDC(-/-) mice were injected with allergen and body temperature, blood pressure, and respiratory function were monitored in each mouse. Blood pressure dropped in both the HDC(-/-) mice and the HDC(+/+) mice. In contrast, respiratory frequency dropped and the expiratory respiration time was elongated only in the HDC(+/+) mice. Body temperature was decreased in the HDC(+/+) mice and was practically unchanged in the HDC(-/-) mice. Histamine receptor antagonists blocked the body temperature drop in the HDC(+/+) mice. Intravenous histamine induced similar patterns of body temperature decrease in the HDC(+/+) mice and the HDC(-/-) mice. Mast cell-deficient W/W (v) mice did not show the decrease in body temperature; this suggests that the histamine that contributed to the decrease in body temperature was derived from mast cells. According to the results of this investigation, in the passive systemic anaphylaxis reaction, respiratory frequency, expiratory time, and body temperature are shown to be controlled by the activity of histamine, but its contribution to blood pressure is negligible.

Male Germline Control of Transposable Elements1

PubMed Central

Bao, Jianqiang; Yan, Wei

2012-01-01

ABSTRACT Repetitive sequences, especially transposon-derived interspersed repetitive elements, account for a large fraction of the genome in most eukaryotes. Despite the repetitive nature, these transposable elements display quantitative and qualitative differences even among species of the same lineage. Although transposable elements contribute greatly as a driving force to the biological diversity during evolution, they can induce embryonic lethality and genetic disorders as a result of insertional mutagenesis and genomic rearrangement. Temporary relaxation of the epigenetic control of retrotransposons during early germline development opens a risky window that can allow retrotransposons to escape from host constraints and to propagate abundantly in the host genome. Because germline mutations caused by retrotransposon activation are heritable and thus can be deleterious to the offspring, an adaptive strategy has evolved in host cells, especially in the germline. In this review, we will attempt to summarize general defense mechanisms deployed by the eukaryotic genome, with an emphasis on pathways utilized by the male germline to confer retrotransposon silencing. PMID:22357546

Does letter rotation slow down orthographic processing in word recognition?

PubMed

Perea, Manuel; Marcet, Ana; Fernández-López, María

2018-02-01

Leading neural models of visual word recognition assume that letter rotation slows down the conversion of the visual input to a stable orthographic representation (e.g., local detectors combination model; Dehaene, Cohen, Sigman, & Vinckier, 2005, Trends in Cognitive Sciences, 9, 335-341). If this premise is true, briefly presented rotated primes should be less effective at activating word representations than those primes with upright letters. To test this question, we conducted a masked priming lexical decision experiment with vertically presented words either rotated 90° or in marquee format (i.e., vertically but with upright letters). We examined the impact of the format on both letter identity (masked identity priming: identity vs. unrelated) and letter position (masked transposed-letter priming: transposed-letter prime vs. replacement-letter prime). Results revealed sizeable masked identity and transposed-letter priming effects that were similar in magnitude for rotated and marquee words. Therefore, the reading cost from letter rotation does not arise in the initial access to orthographic/lexical representations.

Evolutionary interaction between W/Y chromosome and transposable elements.

PubMed

Śliwińska, Ewa B; Martyka, Rafał; Tryjanowski, Piotr

2016-06-01

The W/Y chromosome is unique among chromosomes as it does not recombine in its mature form. The main side effect of cessation of recombination is evolutionary instability and degeneration of the W/Y chromosome, or frequent W/Y chromosome turnovers. Another important feature of W/Y chromosome degeneration is transposable element (TEs) accumulation. Transposon accumulation has been confirmed for all W/Y chromosomes that have been sequenced so far. Models of W/Y chromosome instability include the assemblage of deleterious mutations in protein coding genes, but do not include the influence of transposable elements that are accumulated gradually in the non-recombining genome. The multiple roles of genomic TEs, and the interactions between retrotransposons and genome defense proteins are currently being studied intensively. Small RNAs originating from retrotransposon transcripts appear to be, in some cases, the only mediators of W/Y chromosome function. Based on the review of the most recent publications, we present knowledge on W/Y evolution in relation to retrotransposable element accumulation.

The application of the high throughput sequencing technology in the transposable elements.

PubMed

Liu, Zhen; Xu, Jian-hong

2015-09-01

High throughput sequencing technology has dramatically improved the efficiency of DNA sequencing, and decreased the costs to a great extent. Meanwhile, this technology usually has advantages of better specificity, higher sensitivity and accuracy. Therefore, it has been applied to the research on genetic variations, transcriptomics and epigenomics. Recently, this technology has been widely employed in the studies of transposable elements and has achieved fruitful results. In this review, we summarize the application of high throughput sequencing technology in the fields of transposable elements, including the estimation of transposon content, preference of target sites and distribution, insertion polymorphism and population frequency, identification of rare copies, transposon horizontal transfers as well as transposon tagging. We also briefly introduce the major common sequencing strategies and algorithms, their advantages and disadvantages, and the corresponding solutions. Finally, we envision the developing trends of high throughput sequencing technology, especially the third generation sequencing technology, and its application in transposon studies in the future, hopefully providing a comprehensive understanding and reference for related scientific researchers.

Transposed-letter priming effects in reading aloud words and nonwords.

PubMed

Mousikou, Petroula; Kinoshita, Sachiko; Wu, Simon; Norris, Dennis

2015-10-01

A masked nonword prime generated by transposing adjacent inner letters in a word (e.g., jugde) facilitates the recognition of the target word (JUDGE) more than a prime in which the relevant letters are replaced by different letters (e.g., junpe). This transposed-letter (TL) priming effect has been widely interpreted as evidence that the coding of letter position is flexible, rather than precise. Although the TL priming effect has been extensively investigated in the domain of visual word recognition using the lexical decision task, very few studies have investigated this empirical phenomenon in reading aloud. In the present study, we investigated TL priming effects in reading aloud words and nonwords and found that these effects are of equal magnitude for the two types of items. We take this result as support for the view that the TL priming effect arises from noisy perception of letter order within the prime prior to the mapping of orthography to phonology.

Looking Under a Leidenfrost Drop

NASA Astrophysics Data System (ADS)

Burton, Justin; Sharpe, Aaron; van der Veen, Roeland; Franco, Andres; Nagel, Sidney

2011-11-01

The Leidenfrost effect can be observed when small water drops move around effortlessly without sticking on a hot pan. The transition to a levitated state, where the drops rest on an insulating layer of vapor, occurs at the Leidenfrost temperature. Experiment and theory have examined the lifetime and maximum size of Leidenfrost drops. However, the liquid-vapor interface beneath the drop has not been fully charcterized. We report experiments using laser-light interference to measure the geometry of the liquid-vapor interface. By imaging the interference fringes produced between the bottom surface of the liquid and the hot substrate, we can measure the curvature of the vapor pocket beneath the drop as well as the azimuthal undulations along the neck that sits closest to the surface. From these measurements, we can extrapolate the shape of the bottom of the drop, which fluctuates in time with a period of a few milliseconds for millimeter-sized water drops. Our measurements of the azimuthal neck radius agree with predictions: the difference between the drop and neck radii, (Rd -Rn) ~0.53 λ in the limit of large drops where λ is the capillary length of the fluid. For small drops we recover the result found in that Rn ~Rd2 / λ .

Inverse Leidenfrost effect: self-propelling drops on a bath

NASA Astrophysics Data System (ADS)

Gauthier, Anais; van der Meer, Devaraj; Lohse, Detlef; Physics of Fluids Team

2017-11-01

When deposited on very hot solid, volatile drops can levitate over a cushion of vapor, in the so-called Leidenfrost state. This phenomenon can also be observed on a hot bath and similarly to the solid case, drops are very mobile due to the absence of contact with the substrate that sustains them. We discuss here a situation of ``inverse Leidenfrost effect'' where room-temperature drops levitate on a liquid nitrogen pool - the vapor is generated here by the bath sustaining the relatively hot drop. We show that the drop's movement is not random: the liquid goes across the bath in straight lines, a pattern only disrupted by elastic bouncing on the edges. In addition, the drops are initially self-propelled; first at rest, they accelerate for a few seconds and reach velocities of the order of a few cm/s, before slowing down. We investigate experimentally the parameters that affect their successive acceleration and deceleration, such as the size and nature of the drops and we discuss the origin of this pattern.

Micro-structured heat exchanger for cryogenic mixed refrigerant cycles

NASA Astrophysics Data System (ADS)

Gomse, D.; Reiner, A.; Rabsch, G.; Gietzelt, T.; Brandner, J. J.; Grohmann, S.

2017-12-01

Mixed refrigerant cycles (MRCs) offer a cost- and energy-efficient cooling method for the temperature range between 80 and 200 K. The performance of MRCs is strongly influenced by entropy production in the main heat exchanger. High efficiencies thus require small temperature gradients among the fluid streams, as well as limited pressure drop and axial conduction. As temperature gradients scale with heat flux, large heat transfer areas are necessary. This is best achieved with micro-structured heat exchangers, where high volumetric heat transfer areas can be realized. The reliable design of MRC heat exchangers is challenging, since two-phase heat transfer and pressure drop in both fluid streams have to be considered simultaneously. Furthermore, only few data on the convective boiling and condensation kinetics of zeotropic mixtures is available in literature. This paper presents a micro-structured heat exchanger designed with a newly developed numerical model, followed by experimental results on the single-phase pressure drop and their implications on the hydraulic diameter.

Recent Amplification of the Kangaroo Endogenous Retrovirus, KERV, Limited to the Centromere▿

PubMed Central

Ferreri, Gianni C.; Brown, Judith D.; Obergfell, Craig; Jue, Nathaniel; Finn, Caitlin E.; O'Neill, Michael J.; O'Neill, Rachel J.

2011-01-01

Mammalian retrotransposons, transposable elements that are processed through an RNA intermediate, are categorized as short interspersed elements (SINEs), long interspersed elements (LINEs), and long terminal repeat (LTR) retroelements, which include endogenous retroviruses. The ability of transposable elements to autonomously amplify led to their initial characterization as selfish or junk DNA; however, it is now known that they may acquire specific cellular functions in a genome and are implicated in host defense mechanisms as well as in genome evolution. Interactions between classes of transposable elements may exert a markedly different and potentially more significant effect on a genome than interactions between members of a single class of transposable elements. We examined the genomic structure and evolution of the kangaroo endogenous retrovirus (KERV) in the marsupial genus Macropus. The complete proviral structure of the kangaroo endogenous retrovirus, phylogenetic relationship among relative retroviruses, and expression of this virus in both Macropus rufogriseus and M. eugenii are presented for the first time. In addition, we show the relative copy number and distribution of the kangaroo endogenous retrovirus in the Macropus genus. Our data indicate that amplification of the kangaroo endogenous retrovirus occurred in a lineage-specific fashion, is restricted to the centromeres, and is not correlated with LINE depletion. Finally, analysis of KERV long terminal repeat sequences using massively parallel sequencing indicates that the recent amplification in M. rufogriseus is likely due to duplications and concerted evolution rather than a high number of independent insertion events. PMID:21389136

Isolation and molecular characterization of dTnp1, a mobile and defective transposable element of Nicotiana plumbaginifolia.

PubMed

Meyer, C; Pouteau, S; Rouzé, P; Caboche, M

1994-01-01

By Northern blot analysis of nitrate reductase-deficient mutants of Nicotiana plumbaginifolia, we identified a mutant (mutant D65), obtained after gamma-ray irradiation of protoplasts, which contained an insertion sequence in the nitrate reductase (NR) mRNA. This insertion sequence was localized by polymerase chain reaction (PCR) in the first exon of NR and was also shown to be present in the NR gene. The mutant gene contained a 565 bp insertion sequence that exhibits the sequence characteristics of a transposable element, which was thus named dTnp1. The dTnp1 element has 14 bp terminal inverted repeats and is flanked by an 8-bp target site duplication generated upon transposition. These inverted repeats have significant sequence homology with those of other transposable elements. Judging by its size and the absence of a long open reading frame, dTnp1 appears to represent a defective, although mobile, transposable element. The octamer motif TTTAGGCC was found several times in direct orientation near the 5' and 3' ends of dTnp1 together with a perfect palindrome located after the 5' inverted repeat. Southern blot analysis using an internal probe of dTnp1 suggested that this element occurs as a single copy in the genome of N. plumbaginifolia. It is also present in N. tabacum, but absent in tomato or petunia. The dTnp1 element is therefore of potential use for gene tagging in Nicotiana species.

Crystallization of highly supersaturated solutions - An experimental study

NASA Technical Reports Server (NTRS)

Queen, Brian; Hallett, John

1990-01-01

The crystallization of ammonium sulfate solutions under very high supersaturation is investigated. The results imply that high saturation ratios can exist at least to 30 +/- 5 and possibly higher in smaller drops. Under certain atmospheric conditions highly supersaturated drops can persist at even lower temperatures and humidities.

Relevance of the correlation between precipitation and the 0 °C isothermal altitude for extreme flood estimation

NASA Astrophysics Data System (ADS)

Zeimetz, Fraenz; Schaefli, Bettina; Artigue, Guillaume; García Hernández, Javier; Schleiss, Anton J.

2017-08-01

Extreme floods are commonly estimated with the help of design storms and hydrological models. In this paper, we propose a new method to take into account the relationship between precipitation intensity (P) and air temperature (T) to account for potential snow accumulation and melt processes during the elaboration of design storms. The proposed method is based on a detailed analysis of this P-T relationship in the Swiss Alps. The region, no upper precipitation intensity limit is detectable for increasing temperature. However, a relationship between the highest measured temperature before a precipitation event and the duration of the subsequent event could be identified. An explanation for this relationship is proposed here based on the temperature gradient measured before the precipitation events. The relevance of these results is discussed for an example of Probable Maximum Precipitation-Probable Maximum Flood (PMP-PMF) estimation for the high mountainous Mattmark dam catchment in the Swiss Alps. The proposed method to associate a critical air temperature to a PMP is easily transposable to similar alpine settings where meteorological soundings as well as ground temperature and precipitation measurements are available. In the future, the analyses presented here might be further refined by distinguishing between precipitation event types (frontal versus orographic).

Technical Requirements for On-Site Thermal Desorption of Solid Media Contaminated with Hazardous Chlorinated Organics

DTIC Science & Technology

1997-09-18

scrubbers , detectable dioxin/furans may occur, since dioxin/furans are much more soluble in organics than in water. Carbon adsorption is frequently...air pollution control device is required. Acid gases may be controlled by using a wet or dry scrubber or by using a coated baghouse. Operating...unit: 1. exit treated waste temperature; 2. baghouse pressure drop, venturi pressure drop, or drop in liquid/gas ratio; 3. waste feed rate; 4

Getting in shape: molten wax drop deformation and solidification at an immiscible liquid interface.

PubMed

Beesabathuni, Shilpa N; Lindberg, Seth E; Caggioni, Marco; Wesner, Chris; Shen, Amy Q

2015-05-01

The controlled production of non-spherical shaped particles is important for many applications such as food processing, consumer goods, adsorbents, drug delivery, and optical sensing. In this paper, we investigated the deformation and simultaneous solidification of millimeter size molten wax drops as they impacted an immiscible liquid interface of higher density. By varying initial temperature and viscoelasticity of the molten drop, drop size, impact velocity, viscosity and temperature of the bath fluid, and the interfacial tension between the molten wax and bath fluid, spherical molten wax drops impinged on a cooling water bath and were arrested into non-spherical solidified particles in the form of ellipsoid, mushroom, disc, and flake-like shapes. We constructed cursory phase diagrams for the various particle shapes generated over a range of Weber, Capillary, Reynolds, and Stefan numbers, governed by the interfacial, inertial, viscous, and thermal effects. We solved a simplified heat transfer problem to estimate the time required to initiate the solidification at the interface of a spherical molten wax droplet and cooling aqueous bath after impact. By correlating this time with the molten wax drop deformation history captured from high speed imaging experiments, we elucidate the delicate balance of interfacial, inertial, viscous, and thermal forces that determine the final morphology of wax particles. Copyright © 2015 Elsevier Inc. All rights reserved.

The origin of star-shaped oscillations of Leidenfrost drops

NASA Astrophysics Data System (ADS)

Ma, Xiaolei; Burton, Justin C.

We experimentally investigate the oscillations of Leidenfrost drops of water, liquid nitrogen, ethanol, methanol, acetone and isopropyl alcohol. The drops levitate on a cushion of evaporated vapor over a hot, curved surface which keeps the drops stationary. We observe star-shaped modes along the periphery of the drop, with mode numbers n = 2 to 13. The number of observed modes is sensitive to the properties of the liquid. The pressure oscillation frequency in the vapor layer under the drop is approximately twice that of the drop frequency, which is consistent with a parametric forcing mechanism. However, the Rayleigh and thermal Marangoni numbers are of order 10,000, indicating that convection should play a dominating role as well. Surprisingly, we find that the wavelength and frequency of the oscillations only depend on the thickness of the liquid, which is twice the capillary length, and do not depend on the mode number, substrate temperature, or the substrate curvature. This robust behavior suggests that the wavelength for the oscillations is set by thermal convection inside the drop, and is less dependent on the flow in the vapor layer under the drop

Heat Transfer and Observation of Droplet-Surface Interactions During Air-Mist Cooling at CSP Secondary System Temperatures

NASA Astrophysics Data System (ADS)

Huerta L., Mario E.; Mejía G., M. Esther; Castillejos E., A. Humberto

2016-04-01

Air-mists are key elements in the secondary cooling of modern thin steel slab continuous casters. The selection of water, W, and air, A, flow rates, and pressures in pneumatic nozzles open up a wide spectrum of cooling possibilities by their influence on droplet diameter, d, droplet velocity, v, and water impact flux, w. Nonetheless, due to the harsh environment resulting from the high temperatures and dense mists involved, there is very little information about the correlation between heat flux extracted, - q, and mist characteristics, and none about the dynamics of drop-wall interactions. For obtaining both kinds of information, this work combines a steady-state heat flux measuring method with a visualization technique based on a high-speed camera and a laser illumination system. For wall temperatures, T w, between ~723 K and ~1453 K (~450 °C and ~1180 °C), which correspond to film boiling regime, it was confirmed that - q increases with increase in v, w, and T w and with decrease in d. It should be noticed, however, that the increase in w generally decreases the spray cooling effectiveness because striking drops do not evaporate efficiently due to the interference by liquid remains from previous drops. Visualization of the events happening close to the surface also reveals that the contact time of the liquid with the surface is very brief and that rebounding, splashing, sliding, and levitation of drops lead to ineffective contact with the surface. At the center of the mist footprint, where drops impinge nearly normal to the surface those with enough momentum establish intimate contact with it before forming a vapor layer that pushes away the remaining liquid. Also, some drops are observed sliding upon the surface or levitating close to it; these are drops with low momentum which are influenced by the deflecting air stream. At footprint positions where oblique impingement occurs, frequently drops are spotted sliding or levitating and liquid films flowing in from inner positions are seen generating vapor cushions after having stayed in contact with the surface. Visualization of events taking place under high, ~500 kPa, and low, ~200 kPa, air nozzle pressure, p a, conditions suggests that the considerably larger heat extraction obtained under high p a is related to more frequent impingement of finer and faster drops that result in the formation of a dense fog of tiny secondary drops that moves tangentially close to the surface.

The mixing of rain with near-surface water

Treesearch

Dennis F. Houk

1976-01-01

Rain experiments were run with various temperature differences between the warm rain and the cool receiving water. The rain intensities were uniform and the raindrop sizes were usually uniform (2.2 mm, 3.6 mm, and 5.5 mm diameter drops). Two drop size distributions were also used.

Estimations of temperature deviations in chromatographic columns using isenthalpic plots. I. Theory for isocratic systems.

PubMed

Tarafder, Abhijit; Iraneta, Pamela; Guiochon, Georges; Kaczmarski, Krzysztof; Poe, Donald P

2014-10-31

We propose to use constant enthalpy or isenthalpic diagrams as a tool to estimate the extent of the temperature variations caused by the mobile phase pressure drop along a chromatographic column, e.g. of its cooling in supercritical fluid and its heating in ultra-performance liquid chromatography. Temperature strongly affects chromatographic phenomena. Any of its variations inside the column, whether intended or not, can lead to significant changes in separation performance. Although instruments use column ovens in order to keep constant the column temperature, operating conditions leading to a high pressure drop may cause significant variations of the column temperature, both in the axial and the radial directions, from the set value. Different ways of measuring these temperature variations are available but they are too inconvenient to be employed in many practical situations. In contrast, the thermodynamic plot-based method that we describe here can easily be used with only a ruler and a pencil. They should be helpful in developing methods or in analyzing results in analytical laboratories. Although the most effective application area for this approach should be SFC (supercritical fluid chromatography), it can be applied to any chromatographic conditions in which temperature variations take place along the column due to the pressure drop, e.g. in ultra-high pressure liquid chromatography (UHPLC). The method proposed here is applicable to isocractic conditions only. Copyright © 2014 Elsevier B.V. All rights reserved.

Entanglement cost under positive-partial-transpose-preserving operations.

PubMed

Audenaert, K; Plenio, M B; Eisert, J

2003-01-17

We study the entanglement cost under quantum operations preserving the positivity of the partial transpose (PPT operations). We demonstrate that this cost is directly related to the logarithmic negativity, thereby providing the operational interpretation for this entanglement measure. As examples we discuss general Werner states and arbitrary bipartite Gaussian states. Then we prove that for the antisymmetric Werner state PPT cost and PPT entanglement of distillation coincide. This is the first example of a truly mixed state for which entanglement manipulation is asymptotically reversible, which points towards a unique entanglement measure under PPT operations.

Identification and applications of the Petunia class II Act1/dTph1 transposable element system.

PubMed

Gerats, Tom; Zethof, Jan; Vandenbussche, Michiel

2013-01-01

Transposable genetic elements are considered to be ubiquitous. Despite this, their mutagenic capacity has been exploited in only a few species. The main plant species are maize, Antirrhinum, and Petunia. Representatives of all three major groups of class II elements, viz., hAT-, CACTA- and Mutator-like elements, have been identified in Petunia. Here we focus on the research "history" of the Petunia two-element Act1-dTph1 system and the development of its application in forward- and reverse-genetics studies.

Sequence of retrovirus provirus resembles that of bacterial transposable elements

NASA Astrophysics Data System (ADS)

Shimotohno, Kunitada; Mizutani, Satoshi; Temin, Howard M.

1980-06-01

The nucleotide sequences of the terminal regions of an infectious integrated retrovirus cloned in the modified λ phage cloning vector Charon 4A have been elucidated. There is a 569-base pair direct repeat at both ends of the viral DNA. The cell-virus junctions at each end consist of a 5-base pair direct repeat of cell DNA next to a 3-base pair inverted repeat of viral DNA. This structure resembles that of a transposable element and is consistent with the protovirus hypothesis that retroviruses evolved from the cell genome.

Formation of microbeads during vapor explosions of Field's metal in water

NASA Astrophysics Data System (ADS)

Kouraytem, N.; Li, E. Q.; Thoroddsen, S. T.

2016-06-01

We use high-speed video imaging to investigate vapor explosions during the impact of a molten Field's metal drop onto a pool of water. These explosions occur for temperatures above the Leidenfrost temperature and are observed to occur in up to three stages as the metal temperature is increased, with each explosion being more powerful that the preceding one. The Field's metal drop breaks up into numerous microbeads with an exponential size distribution, in contrast to tin droplets where the vapor explosion deforms the metal to form porous solid structures. We compare the characteristic bead size to the wavelength of the fastest growing mode of the Rayleigh-Taylor instability.

Smoothed particle hydrodynamics simulations of evaporation and explosive boiling of liquid drops in microgravity.

PubMed

Sigalotti, Leonardo Di G; Troconis, Jorge; Sira, Eloy; Peña-Polo, Franklin; Klapp, Jaime

2015-07-01

The rapid evaporation and explosive boiling of a van der Waals (vdW) liquid drop in microgravity is simulated numerically in two-space dimensions using the method of smoothed particle hydrodynamics. The numerical approach is fully adaptive and incorporates the effects of surface tension, latent heat, mass transfer across the interface, and liquid-vapor interface dynamics. Thermocapillary forces are modeled by coupling the hydrodynamics to a diffuse-interface description of the liquid-vapor interface. The models start from a nonequilibrium square-shaped liquid of varying density and temperature. For a fixed density, the drop temperature is increased gradually to predict the point separating normal boiling at subcritical heating from explosive boiling at the superheat limit for this vdW fluid. At subcritical heating, spontaneous evaporation produces stable drops floating in a vapor atmosphere, while at near-critical heating, a bubble is nucleated inside the drop, which then collapses upon itself, leaving a smaller equilibrated drop embedded in its own vapor. At the superheat limit, unstable bubble growth leads to either fragmentation or violent disruption of the liquid layer into small secondary drops, depending on the liquid density. At higher superheats, explosive boiling occurs for all densities. The experimentally observed wrinkling of the bubble surface driven by rapid evaporation followed by a Rayleigh-Taylor instability of the thin liquid layer and the linear growth of the bubble radius with time are reproduced by the simulations. The predicted superheat limit (T(s)≈0.96) is close to the theoretically derived value of T(s)=1 at zero ambient pressure for this vdW fluid.

Low Gravity Freefall Facilities

NASA Technical Reports Server (NTRS)

1981-01-01

Composite of Marshall Space Flight Center's Low-Gravity Free Fall Facilities.These facilities include a 100-meter drop tower and a 100-meter drop tube. The drop tower simulates in-flight microgravity conditions for up to 4.2 seconds for containerless processing experiments, immiscible fluids and materials research, pre-flight hardware design test and flight experiment simulation. The drop tube simulates in-flight microgravity conditions for up to 4.6 seconds and is used extensively for ground-based microgravity convection research in which extremely small samples are studied. The facility can provide deep undercooling for containerless processing experiments that require materials to remain in a liquid phase when cooled below the normal solidification temperature.

Thermocapillary-Induced Phase Separation with Coalescence

NASA Technical Reports Server (NTRS)

Davis, Robert H.

2003-01-01

Research has been undertaken on interactions of two or more deformable drops (or bubbles) in a viscous fluid and subject to a temperature, gravitational, or flow field. An asymptotic theory for nearly spherical drops shows that small deformations reduce the coalescence and phase separation rates. Boundary-integral simulations for large deformations show that bubbles experience alignment and enhanced coalescence, whereas more viscous drops may break as a result of hydrodynamic interactions. Experiments for buoyancy motion confirm these observations. Simulations of the sedimentation of many drops show clustering phenomena due to deformations, which lead to enhanced phase separation rates, and simulations of sheared emulsions show that deformations cause a reduction in the effective viscosity.

Microgravity

NASA Image and Video Library

1981-03-30

Composite of Marshall Space Flight Center's Low-Gravity Free Fall Facilities.These facilities include a 100-meter drop tower and a 100-meter drop tube. The drop tower simulates in-flight microgravity conditions for up to 4.2 seconds for containerless processing experiments, immiscible fluids and materials research, pre-flight hardware design test and flight experiment simulation. The drop tube simulates in-flight microgravity conditions for up to 4.6 seconds and is used extensively for ground-based microgravity convection research in which extremely small samples are studied. The facility can provide deep undercooling for containerless processing experiments that require materials to remain in a liquid phase when cooled below the normal solidification temperature.

Unsteady Thermocapillary Migration of Isolated Drops in Creeping Flow

NASA Technical Reports Server (NTRS)

Dill, Loren H.; Balasubramaniam, R.

1992-01-01

The problem of an isolated immiscible drop that slowly migrates due to unsteady thermocapillary stresses is considered. All physical properties except for interfacial tension are assumed constant for the two Newtonian fluids. Explicit expressions are found for the migration rate and stream functions in the Laplace domain. The resulting microgravity theory is useful, e.g., in predicting the distance a drop will migrate due to an impulsive interfacial temperature gradient as well as the time required to attain steady flow conditions from an initially resting state.

Effect of water temperature on biofouling development in reverse osmosis membrane systems.

PubMed

Farhat, N M; Vrouwenvelder, J S; Van Loosdrecht, M C M; Bucs, Sz S; Staal, M

2016-10-15

Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Monitoring the hatch time of individual chicken embryos.

PubMed

Romanini, C E B; Exadaktylos, V; Tong, Q; McGonnel, I; Demmers, T G M; Bergoug, H; Eterradossi, N; Roulston, N; Garain, P; Bahr, C; Berckmans, D

2013-02-01

This study investigated variations in eggshell temperature (T(egg)) during the hatching process of broiler eggs. Temperature sensors monitored embryo temperature by registering T(egg) every minute. Measurements carried out on a sample of 40 focal eggs revealed temperature drops between 2 to 6°C during the last 3 d of incubation. Video cameras recorded the hatching process and served as the gold standard reference for manually labeling the hatch times of chicks. Comparison between T(egg) drops and the hatch time of individuals revealed a time synchronization with 99% correlation coefficient and an absolute average time difference up to 25 min. Our findings suggest that attaching temperature sensors to eggshells is a precise tool for monitoring the hatch time of individual chicks. Individual hatch monitoring registers the biological age of chicks and facilitates an accurate and reliable means to count hatching results and manage the hatch window.

The electrical resistance of gold-capped chromium thin films

NASA Astrophysics Data System (ADS)

Ohashi, Masashi; Sawabu, Masaki; Ohashi, Kohei; Miyagawa, Masahiro; Maeta, Kae; Kubota, Takahide; Takanashi, Koki

2018-03-01

We studied the electrical resistance of polycrystalline chromium films capped by a gold layer. No anomaly was detected by resistance measurements of 10 nm thick film around room temperature, indicating that the antiferromagnetic interaction may be suppressed as decreasing the thickness of the chromium film. The sheet resistance Rs (T) curves differ from polycrystalline chromium films in previous studies because of the electrical current flows through a gold capping layer. On the other hand, the resistance drop is observed at T C = 1.15±0.05 K as that of polycrystalline chromium films in the previous report. It means that such resistance drop is not related to the chromium oxide layer on a polycrystalline chromium films. However, it is difficult to conclude that superconducting transition occurs because of the large residual resistance below the temperature where the resistance drop is observed.

Brain Basics: Understanding Sleep

MedlinePlus

... slow, and muscles relax even further. Your body temperature drops and eye movements stop. Brain wave activity ... functions from daily fluctuations in wakefulness to body temperature, metabolism, and the release of hormones. They control ...

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

Sai K. Mylavarapu; Xiaodong Sun; Richard E. Glosup

In high-temperature gas-cooled reactors, such as a very high temperature reactor (VHTR), an intermediate heat exchanger (IHX) is required to efficiently transfer the core thermal output to a secondary fluid for electricity generation with an indirect power cycle and/or process heat applications. Currently, there is no proven high-temperature (750–800 °C or higher) compact heat exchanger technology for high-temperature reactor design concepts. In this study, printed circuit heat exchanger (PCHE), a potential IHX concept for high-temperature applications, has been investigated for their heat transfer and pressure drop characteristics under high operating temperatures and pressures. Two PCHEs, each having 10 hot andmore » 10 cold plates with 12 channels (semicircular cross-section) in each plate are fabricated using Alloy 617 plates and tested for their performance in a high-temperature helium test facility (HTHF). The PCHE inlet temperature and pressure were varied from 85 to 390 °C/1.0–2.7 MPa for the cold side and 208–790 °C/1.0–2.7 MPa for the hot side, respectively, while the mass flow rate of helium was varied from 15 to 49 kg/h. This range of mass flow rates corresponds to PCHE channel Reynolds numbers of 950 to 4100 for the cold side and 900 to 3900 for the hot side (corresponding to the laminar and laminar-to-turbulent transition flow regimes). The obtained experimental data have been analyzed for the pressure drop and heat transfer characteristics of the heat transfer surface of the PCHEs and compared with the available models and correlations in the literature. In addition, a numerical treatment of hydrodynamically developing and hydrodynamically fully-developed laminar flow through a semicircular duct is presented. Relations developed for determining the hydrodynamic entrance length in a semicircular duct and the friction factor (or pressure drop) in the hydrodynamic entry length region for laminar flow through a semicircular duct are given. Various hydrodynamic entrance region parameters, such as incremental pressure drop number, apparent Fanning friction factor, and hydrodynamic entrance length in a semicircular duct have been numerically estimated.« less

Genome wide survey, discovery and evolution of repetitive elements in three Entamoeba species

PubMed Central

Lorenzi, Hernan; Thiagarajan, Mathangi; Haas, Brian; Wortman, Jennifer; Hall, Neil; Caler, Elisabet

2008-01-01

Background Identification and mapping of repetitive elements is a key step for accurate gene prediction and overall structural annotation of genomes. During the assembly and annotation of three highly repetitive amoeba genomes, Entamoeba histolytica, Entamoeba dispar, and Entamoeba invadens, we performed comparative sequence analysis to identify and map all class I and class II transposable elements in their sequences. Results Here, we report the identification of two novel Entamoeba-specific repeats: ERE1 and ERE2; ERE1 is spread across the three genomes and associated with different repeats in a species-specific manner, while ERE2 is unique to E. histolytica. We also report the identification of two novel subfamilies of LINE and SINE retrotransposons in E. dispar and provide evidence for how the different LINE and SINE subfamilies evolved in these species. Additionally, we found a putative transposase-coding gene in E. histolytica and E. dispar related to the mariner transposon Hydargos from E. invadens. The distribution of transposable elements in these genomes is markedly skewed with a tendency of forming clusters. More than 70% of the three genomes have a repeat density below their corresponding average value indicating that transposable elements are not evenly distributed. We show that repeats and repeat-clusters are found at syntenic break points between E. histolytica and E. dispar and hence, could work as recombination hot spots promoting genome rearrangements. Conclusion The mapping of all transposable elements found in these parasites shows that repeat coverage is up to three times higher than previously reported. LINE, ERE1 and mariner elements were present in the common ancestor to the three Entamoeba species while ERE2 was likely acquired by E. histolytica after its separation from E. dispar. We demonstrate that E. histolytica and E. dispar share their entire repertoire of LINE and SINE retrotransposons and that Eh_SINE3/Ed_SINE1 originated as a chimeric SINE from Eh/Ed_SINE2 and Eh_SINE1/Ed_SINE3. Our work shows that transposable elements are organized in clusters, frequently found at syntenic break points providing insights into their contribution to chromosome instability and therefore, to genomic variation and speciation in these parasites. PMID:19077187

DNA transposons have colonized the genome of the giant virus Pandoravirus salinus.

PubMed

Sun, Cheng; Feschotte, Cédric; Wu, Zhiqiang; Mueller, Rachel Lockridge

2015-06-12

Transposable elements are mobile DNA sequences that are widely distributed in prokaryotic and eukaryotic genomes, where they represent a major force in genome evolution. However, transposable elements have rarely been documented in viruses, and their contribution to viral genome evolution remains largely unexplored. Pandoraviruses are recently described DNA viruses with genome sizes that exceed those of some prokaryotes, rivaling parasitic eukaryotes. These large genomes appear to include substantial noncoding intergenic spaces, which provide potential locations for transposable element insertions. However, no mobile genetic elements have yet been reported in pandoravirus genomes. Here, we report a family of miniature inverted-repeat transposable elements (MITEs) in the Pandoravirus salinus genome, representing the first description of a virus populated with a canonical transposable element family that proliferated by transposition within the viral genome. The MITE family, which we name Submariner, includes 30 copies with all the hallmarks of MITEs: short length, terminal inverted repeats, TA target site duplication, and no coding capacity. Submariner elements show signs of transposition and are undetectable in the genome of Pandoravirus dulcis, the closest known relative Pandoravirus salinus. We identified a DNA transposon related to Submariner in the genome of Acanthamoeba castellanii, a species thought to host pandoraviruses, which contains remnants of coding sequence for a Tc1/mariner transposase. These observations suggest that the Submariner MITEs of P. salinus belong to the widespread Tc1/mariner superfamily and may have been mobilized by an amoebozoan host. Ten of the 30 MITEs in the P. salinus genome are located within coding regions of predicted genes, while others are close to genes, suggesting that these transposons may have contributed to viral genetic novelty. Our discovery highlights the remarkable ability of DNA transposons to colonize and shape genomes from all domains of life, as well as giant viruses. Our findings continue to blur the division between viral and cellular genomes, adhering to the emerging view that the content, dynamics, and evolution of the genomes of giant viruses do not substantially differ from those of cellular organisms.

Identification of a high frequency transposon induced by tissue culture, nDaiZ, a member of the hAT family in rice.

PubMed

Huang, Jian; Zhang, Kewei; Shen, Yi; Huang, Zejun; Li, Ming; Tang, Ding; Gu, Minghong; Cheng, Zhukuan

2009-03-01

Recent completion of rice genome sequencing has revealed that more than 40% of its genome consists of repetitive sequences, and most of them are related to inactive transposable elements. In the present study, a transposable element, nDaiZ0, which is induced by tissue culture with high frequency, was identified by sequence analysis of an allelic line of the golden hull and internode 2 (gh2) mutant, which was integrated into the forth exon of GH2. The 528-bp nDaiZ0 has 14-bp terminal inverted repeats (TIRs), and generates an 8-bp duplication of its target sites (TSD) during its mobilization. nDaiZs are non-autonomous transposons and have no coding capacity. Bioinformatics analysis and southern blot hybridization showed that at least 16 copies of nDaiZ elements exist in the japonica cultivar Nipponbare genome and 11 copies in the indica cultivar 93-11 genome. During tissue culture, only one copy, nDaiZ9, located on chromosome 5 in the genome of Nipponbare can be activated with its transposable frequency reaching 30%. However, nDaiZ9 was not present in the 93-11 genome. The larger elements, DaiZs, were further identified by database searching using nDaiZ0 as a query because they share similar TIRs and subterminal sequences. DaiZ can also generate an 8-bp TSD. DaiZ elements contain a conserved region with a high similarity to the hAT dimerization motif, suggesting that the nDaiZ-DaiZ transposon system probably belongs to the hAT superfamily of class II transposons. Phylogenetic analysis indicated that it is a new type of plant hAT-like transposon. Although nDaiZ is activated by tissue culture, the high transposable frequency indicates that it could become a useful gene tagging system for rice functional genomic studies. In addition, the mechanism of the high transposable ability of nDaiZ9 is discussed.

Superhydrophobicity of biological and technical surfaces under moisture condensation: stability in relation to surface structure.

PubMed

Mockenhaupt, Bernd; Ensikat, Hans-Jürgen; Spaeth, Manuel; Barthlott, Wilhelm

2008-12-02

The stability of superhydrophobic properties of eight plants and four technical surfaces in respect to water condensation has been compared. Contact and sliding angles were measured after application of water drops of ambient temperature (20 degrees C) onto cooled surfaces. Water evaporating from the drops condensed, due to the temperature difference between the drops and the surface, on the cooled samples, forming "satellite droplets" in the vicinity of the drops. Surface cooling to 15, 10, and 5 degrees C showed a gradual decrease of superhydrophobicity. The decrease was dependent on the specific surface architecture of the sample. The least decrease was found on hierarchically structured surfaces with a combination of a coarse microstructure and submicrometer-sized structures, similar to that of the Lotus leaf. Control experiments with glycerol droplets, which show no evaporation, and thus no condensation, were carried out to verify that the effects with water were caused by condensation from the drop (secondary condensation). Furthermore, the superhydrophobic properties after condensation on cooled surfaces from a humid environment for 10 min were examined. After this period, the surfaces were covered with spherical water droplets, but most samples retained their superhydrophobicity. Again, the best stability of the water-repellent properties was found on hierarchically structured surfaces similar to that of the Lotus leaf.

Evaporation Flux Distribution of Drops on a Hydrophilic or Hydrophobic Flat Surface by Molecular Simulations.

PubMed

Xie, Chiyu; Liu, Guangzhi; Wang, Moran

2016-08-16

The evaporation flux distribution of sessile drops is investigated by molecular dynamic simulations. Three evaporating modes are classified, including the diffusion dominant mode, the substrate heating mode, and the environment heating mode. Both hydrophilic and hydrophobic drop-substrate interactions are considered. To count the evaporation flux distribution, which is position dependent, we proposed an azimuthal-angle-based division method under the assumption of spherical crown shape of drops. The modeling results show that the edge evaporation, i.e., near the contact line, is enhanced for hydrophilic drops in all the three modes. The surface diffusion of liquid molecular absorbed on solid substrate for hydrophilic cases plays an important role as well as the space diffusion on the enhanced evaporation rate at the edge. For hydrophobic drops, the edge evaporation flux is higher for the substrate heating mode, but lower than elsewhere of the drop for the diffusion dominant mode; however, a nearly uniform distribution is found for the environment heating mode. The evidence shows that the temperature distribution inside drops plays a key role in the position-dependent evaporation flux.

Noncontact measurement of high temperature using optical fiber sensors

NASA Technical Reports Server (NTRS)

Claus, R. O.

1990-01-01

The primary goal of this research program was the investigation and application of noncontact temperature measurement techniques using optical techniques and optical fiber methods. In particular, a pyrometer utilizing an infrared optical light pipe and a multiwavelength filtering approach was designed, revised, and tested. This work was motivated by the need to measure the temperatures of small metallic pellets (approximately 3 mm diameter) in free fall at the Microgravity Materials Processing Drop Tube at NASA Marshall Space Flight Center. In addition, research under this program investigated the adaptation of holography technology to optical fiber sensors, and also examined the use of rare-earth dopants in optical fibers for use in measuring temperature. The pyrometer development effort involved both theoretical analysis and experimental tests. For the analysis, a mathematical model based on radiative transfer principles was derived. Key parameter values representative of the drop tube system, such as particle size, tube diameter and length, and particle temperature, were used to determine an estimate of the radiant flux that will be incident on the face of an optical fiber or light pipe used to collect radiation from the incandescent falling particle. An extension of this work examined the advantage of inclining or tilting the collecting fiber to increase the time that the falling particle remains in the fiber field-of-view. Those results indicate that increases in total power collected of about 15 percent may be realized by tilting the fiber. In order to determine the suitability of alternative light pipes and optical fibers, and experimental set-up for measuring the transmittance and insertion loss of infrared fibers considered for use in the pyrometer was assembled. A zirconium fluoride optical fiber and several bundles of hollow core fiber of varying diameters were tested. A prototype two-color pyrometer was assembled and tested at Virginia Tech, and then tested on the Drop Tube at Marshall Space Flight Center. Radiation from 5 mm diameter niobium drops falling in the Drop Tube was successfully detected, and recorded for later analysis. Subsequent analysis indicated that the imaging of light output from the light pipe onto the detector active areas was not identical for both detectors.

Acoustic Levitation With One Transducer

NASA Technical Reports Server (NTRS)

Barmatz, Martin B.

1987-01-01

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

DNS of moderate-temperature gaseous mixing layers laden with multicomponent-fuel drops

NASA Technical Reports Server (NTRS)

Clercq, P. C. Le; Bellan, J.

2004-01-01

A formulation representing multicomponent-fuel (MC-fuel) composition as a Probability Distribution Function (PDF) depending on the molar weight is used to construct a model of a large number of MC-fuel drops evaporating in a gas flow, so as to assess the extent of fuel specificity on the vapor composition.

The Transposable Element Mariner Mediates Germline Transformation in Drosophila Melanogaster

PubMed Central

Lidholm, D. A.; Lohe, A. R.; Hartl, D. L.

1993-01-01

A vector for germline transformation in Drosophila melanogaster was constructed using the transposable element mariner. The vector, denoted pMlwB, contains a mariner element disrupted by an insertion containing the wild-type white gene from D. melanogaster, the β-galactosidase gene from Escherichia coli and sequences that enable plasmid replication and selection in E. coli. The white gene is controlled by the promoter of the D. melanogaster gene for heat-shock protein 70, and the β-galactosidase gene is flanked upstream by the promoter of the transposable element P as well as that of mariner. The MlwB element was introduced into the germline of D. melanogaster by co-injection into embryos with an active mariner element, Mos1, which codes for a functional transposase and serves as a helper. Two independent germline insertions were isolated and characterized. The results show that the MlwB element inserted into the genome in a mariner-dependent manner with the termini of the inverted repeats inserted at a TA dinucleotide. Both insertions exhibit an unexpected degree of germline and somatic stability, even in the presence of an active mariner element in the genetic background. These results demonstrate that the mariner transposable element, which is small (1286 bp) and relatively homogeneous in size among different copies, is nevertheless capable of promoting the insertion of the large (13.2 kb) MlwB element. Because of the widespread phylogenetic distribution of mariner among insects, these results suggest that mariner might provide a wide hostrange transformation vector for insects. PMID:8394264

The industrial melanism mutation in British peppered moths is a transposable element.

PubMed

Van't Hof, Arjen E; Campagne, Pascal; Rigden, Daniel J; Yung, Carl J; Lingley, Jessica; Quail, Michael A; Hall, Neil; Darby, Alistair C; Saccheri, Ilik J

2016-06-02

Discovering the mutational events that fuel adaptation to environmental change remains an important challenge for evolutionary biology. The classroom example of a visible evolutionary response is industrial melanism in the peppered moth (Biston betularia): the replacement, during the Industrial Revolution, of the common pale typica form by a previously unknown black (carbonaria) form, driven by the interaction between bird predation and coal pollution. The carbonaria locus has been coarsely localized to a 200-kilobase region, but the specific identity and nature of the sequence difference controlling the carbonaria-typica polymorphism, and the gene it influences, are unknown. Here we show that the mutation event giving rise to industrial melanism in Britain was the insertion of a large, tandemly repeated, transposable element into the first intron of the gene cortex. Statistical inference based on the distribution of recombined carbonaria haplotypes indicates that this transposition event occurred around 1819, consistent with the historical record. We have begun to dissect the mode of action of the carbonaria transposable element by showing that it increases the abundance of a cortex transcript, the protein product of which plays an important role in cell-cycle regulation, during early wing disc development. Our findings fill a substantial knowledge gap in the iconic example of microevolutionary change, adding a further layer of insight into the mechanism of adaptation in response to natural selection. The discovery that the mutation itself is a transposable element will stimulate further debate about the importance of 'jumping genes' as a source of major phenotypic novelty.

Correlation of LNCR rasiRNAs Expression with Heterochromatin Formation during Development of the Holocentric Insect Spodoptera frugiperda

PubMed Central

Stanojcic, Slavica; Gimenez, Sylvie; Permal, Emmanuelle; Cousserans, François; Quesneville, Hadi; Fournier, Philippe; d'Alençon, Emmanuelle

2011-01-01

Repeat-associated small interfering RNAs (rasiRNAs) are derived from various genomic repetitive elements and ensure genomic stability by silencing endogenous transposable elements. Here we describe a novel subset of 46 rasiRNAs named LNCR rasiRNAs due to their homology with one long non-coding RNA (LNCR) of Spodoptera frugiperda. LNCR operates as the intermediate of an unclassified transposable element (TE-LNCR). TE-LNCR is a very invasive transposable element, present in high copy numbers in the S. frugiperda genome. LNCR rasiRNAs are single-stranded RNAs without a prominent nucleotide motif, which are organized in two distinct, strand-specific clusters. The expression of LNCR and LNCR rasiRNAs is developmentally regulated. Formation of heterochromatin in the genomic region where three copies of the TE-LNCR are embedded was followed by chromatin immunoprecipitation (ChIP) and we observed this chromatin undergo dynamic changes during development. In summary, increased LNCR expression in certain developmental stages is followed by the appearance of a variety of LNCR rasiRNAs which appears to correlate with subsequent accumulation of a heterochromatic histone mark and silencing of the genomic region with TE-LNCR. These results support the notion that a repeat-associated small interfering RNA pathway is linked to heterochromatin formation and/or maintenance during development to establish repression of the TE-LNCR transposable element. This study provides insights into the rasiRNA silencing pathway and its role in the formation of fluctuating heterochromatin during the development of one holocentric organism. PMID:21980354

Extremal states of positive partial transpose in a system of three qubits

NASA Astrophysics Data System (ADS)

Steensgaard Garberg, Øyvind; Irgens, Børge; Myrheim, Jan

2013-03-01

We have studied mixed states in the system of three qubits with the property that all their partial transposes are positive; these are called PPT states. We classify a PPT state by the ranks of the state itself and its three single partial transposes. In random numerical searches, we find entangled PPT states with a large variety of rank combinations. For ranks equal to five or higher, we find both extremal and nonextremal PPT states of nearly every rank combination, with the restriction that the square sum of the four ranks of an extremal PPT state can be at most 193. We have studied especially the rank-four entangled PPT states, which are found to have rank four for every partial transpose. These states are all extremal because of the previously known result that every PPT state of rank three or less is separable. We find two distinct classes of rank-4444 entangled PPT states, identified by a real valued quadratic expression invariant under local SL(2,C) transformations, mathematically equivalent to Lorentz transformations. This quadratic Lorentz invariant is nonzero for one class of states (type I in our terminology) and zero for the other class (type II). The previously known states based on unextendible product bases are a nongeneric subclass of the type-I states. We present analytical constructions of states of both types, general enough to reproduce all the rank-4444 PPT states we have found numerically. We can not exclude the possibility that there exist nongeneric rank-four PPT states that we do not find in our random numerical searches.

The effect of temperature, matrix alloying and substrate coatings on wettability and shear strength of Al/Al2O3 couples

NASA Astrophysics Data System (ADS)

Sobczak, N.; Ksiazek, M.; Radziwill, W.; Asthana, R.; Mikulowski, B.

2004-03-01

A fresh approach has been advanced to examine in the Al/Al2O3 system the effects of temperature, alloying of Al with Ti or Sn, and Ti and Sn coatings on the substrate, on contact angles measured using a sessile-drop test, and on interface strength measured using a modified push-off test that allows shearing of solidified droplets with less than 90 deg contact angle. In the modified test, the solidified sessile-drop samples are bisected perpendicular to the drop/Al2O3 interface at the midplane of the contact circle to obtain samples that permit bond strength measurement by stress application to the flat surface of the bisected couple. The test results show that interface strength is strongly influenced by the wetting properties; low contact angles correspond to high interface strength, which also exhibits a strong temperature dependence. An increase in the wettability test temperature led to an increase in the interface strength in the low-temperature range where contact angles were large and wettability was poor. The room-temperature shear tests conducted on thermally cycled sessile-drop test specimens revealed the effect of chemically formed interfacial oxides; a weakening of the thermally cycled Al/Al2O3 interface was caused under the following conditions: (1) slow contact heating and short contact times in the wettability test, and (2) fast contact heating and longer contact times. The addition of 6 wt pct Ti or 7 wt pct Sn to Al only marginally influenced the contact angle and interfacial shear strength. However, Al2O3 substrates having thin (<1 µm) Ti coatings yielded relatively low contact angles and high bond strength, which appears to be related to the dissolution of the coating in Al and formation of a favorable interface structure.

Thermocapillary Migration and Interactions of Bubbles and Drops

NASA Technical Reports Server (NTRS)

Subramaniam, R. Shankar; Balasubramaniam, R.; Wozniak, G.; Hadland, P. H.

1999-01-01

Experiments were performed aboard the LMS mission of the Space Shuttle in summer 1996 in the BDPU on isolated air bubbles and Fluorinert FC-75 drops as well as on interacting bubbles/drops migrating in a temperature gradient in a Dow-Corning DC-200 series silicone oil of nominal viscosity 10 centistokes. The data, recorded in the form of videotape images as well as cine images in selected runs, have been analyzed. The behavior of the isolated objects is consistent with earlier observations made aboard the IML-2 mission while the range of Reynolds and Marangoni numbers has been extended substantially over that in the IML-2 experiments. Large bubbles were found to be slightly deformed to an oblate shape while no deformation could be detected in the case of similarly large drops. Results on interacting drops and bubbles display interesting and unanticipated features. In some experiments, drops are found to follow a three-dimensional trajectory. In others, trailing drops and bubbles are found to move off the axis of the cell when migrating behind a leading drop or bubble which moves along the axis. In this type of run, if the trailing drop is sufficiently large, it is found to pass the leading drop. Finally, behavior similar to that observed in IML-2, namely that a small leading drop slows the movement of a larger trailing drop moving along the cell axis, was observed as well.

Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler

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

Ardhapurkar, P. M.; Sridharan, Arunkumar; Atrey, M. D.

2014-01-29

A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends onmore » the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models.« less

Drop evaporation on superhydrophobic PTFE surfaces driven by contact line dynamics.

PubMed

Ramos, S M M; Dias, J F; Canut, B

2015-02-15

In the present study, we experimentally study the evaporation modes and kinetics of sessile drops of water on highly hydrophobic surfaces (contact angle ∼160°), heated to temperatures ranging between 40° and 70 °C. These surfaces were initially constructed by means of controlled tailoring of polytetrafluoroethylene (PTFE) substrates. The evaporation of droplets was observed to occur in three distinct phases, which were the same for the different substrate temperatures. The drops started to evaporate in the constant contact radius (CCR) mode, then switched to a more complex mode characterized by a set of stick-slip events accompanied by a decrease in contact angle, and finally shifted to a mixed mode in which the contact radius and contact angle decreased simultaneously until the drops had completely evaporated. It is shown that in the case of superhydrophobic surfaces, the energy barriers (per unit length) associated with the stick-slip motion of a drop ranges in the nJ m(-1) scale. Furthermore, analysis of the evaporation rates, determined from experimental data show that, even in the CCR mode, a linear relationship between V(2/3) and the evaporation time is verified. The values of the evaporation rate constants are found to be higher in the pinned contact line regime (the CCR mode) than in the moving contact line regime. This behavior is attributed to the drop's higher surface to volume ratio in the CCR mode. Copyright © 2014 Elsevier Inc. All rights reserved.

Small RNAs, big impact: small RNA pathways in transposon control and their effect on the host stress response.

PubMed

Wheeler, Bayly S

2013-12-01

Transposons are mobile genetic elements that are a major constituent of most genomes. Organisms regulate transposable element expression, transposition, and insertion site preference, mitigating the genome instability caused by uncontrolled transposition. A recent burst of research has demonstrated the critical role of small non-coding RNAs in regulating transposition in fungi, plants, and animals. While mechanistically distinct, these pathways work through a conserved paradigm. The presence of a transposon is communicated by the presence of its RNA or by its integration into specific genomic loci. These signals are then translated into small non-coding RNAs that guide epigenetic modifications and gene silencing back to the transposon. In addition to being regulated by the host, transposable elements are themselves capable of influencing host gene expression. Transposon expression is responsive to environmental signals, and many transposons are activated by various cellular stresses. TEs can confer local gene regulation by acting as enhancers and can also confer global gene regulation through their non-coding RNAs. Thus, transposable elements can act as stress-responsive regulators that control host gene expression in cis and trans.

Expressing genes do not forget their LINEs: transposable elements and gene expression

PubMed Central

Kines, Kristine J.; Belancio, Victoria P.

2012-01-01

1. ABSTRACT Historically the accumulated mass of mammalian transposable elements (TEs), particularly those located within gene boundaries, was viewed as a genetic burden potentially detrimental to the genomic landscape. This notion has been strengthened by the discovery that transposable sequences can alter the architecture of the transcriptome, not only through insertion, but also long after the integration process is completed. Insertions previously considered harmless are now known to impact the expression of host genes via modification of the transcript quality or quantity, transcriptional interference, or by the control of pathways that affect the mRNA life-cycle. Conversely, several examples of the evolutionary advantageous impact of TEs on the host gene structure that diversified the cellular transcriptome are reported. TE-induced changes in gene expression can be tissue-or disease-specific, raising the possibility that the impact of TE sequences may vary during development, among normal cell types, and between normal and disease-affected tissues. The understanding of the rules and abundance of TE-interference with gene expression is in its infancy, and its contribution to human disease and/or evolution remains largely unexplored. PMID:22201807

Loss-of-function of a ubiquitin-related modifier promotes the mobilization of the active MITE mPing.

PubMed

Tsukiyama, Takuji; Teramoto, Shota; Yasuda, Kanako; Horibata, Akira; Mori, Nanako; Okumoto, Yutaka; Teraishi, Masayoshi; Saito, Hiroki; Onishi, Akiko; Tamura, Kanako; Tanisaka, Takatoshi

2013-05-01

Miniature inverted-repeat transposable elements (MITEs) are widespread in both prokaryotic and eukaryotic genomes, where their copy numbers can attain several thousands. Little is known, however, about the genetic factor(s) affecting their transpositions. Here, we show that disruption of a gene encoding ubiquitin-like protein markedly enhances the transposition activity of a MITE mPing in intact rice plants without any exogenous stresses. We found that the transposition activity of mPing is far higher in the lines harboring a non-functional allele at the Rurm1 (Rice ubiquitin-related modifier-1) locus than in the wild-type line. Although the alteration of cytosine methylation pattern triggers the activation of transposable elements under exogenous stress conditions, the methylation degrees in the whole genome, the mPing-body region, and the mPing-flanking regions of the non-functional Rurm1 line were unchanged. This study provides experimental evidence for one of the models of genome shock theory that genetic accidents within cells enhance the transposition activities of transposable elements.

HTT-DB: horizontally transferred transposable elements database.

PubMed

Dotto, Bruno Reis; Carvalho, Evelise Leis; Silva, Alexandre Freitas; Duarte Silva, Luiz Fernando; Pinto, Paulo Marcos; Ortiz, Mauro Freitas; Wallau, Gabriel Luz

2015-09-01

Horizontal transfer of transposable (HTT) elements among eukaryotes was discovered in the mid-1980s. As then, >300 new cases have been described. New findings about HTT are revealing the evolutionary impact of this phenomenon on host genomes. In order to provide an up to date, interactive and expandable database for such events, we developed the HTT-DB database. HTT-DB allows easy access to most of HTT cases reported along with rich information about each case. Moreover, it allows the user to generate tables and graphs based on searches using Transposable elements and/or host species classification and export them in several formats. This database is freely available on the web at http://lpa.saogabriel.unipampa.edu.br:8080/httdatabase. HTT-DB was developed based on Java and MySQL with all major browsers supported. Tools and software packages used are free for personal or non-profit projects. bdotto82@gmail.com or gabriel.wallau@gmail.com. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The Helicase Aquarius/EMB-4 Is Required to Overcome Intronic Barriers to Allow Nuclear RNAi Pathways to Heritably Silence Transcription.

PubMed

Akay, Alper; Di Domenico, Tomas; Suen, Kin M; Nabih, Amena; Parada, Guillermo E; Larance, Mark; Medhi, Ragini; Berkyurek, Ahmet C; Zhang, Xinlian; Wedeles, Christopher J; Rudolph, Konrad L M; Engelhardt, Jan; Hemberg, Martin; Ma, Ping; Lamond, Angus I; Claycomb, Julie M; Miska, Eric A

2017-08-07

Small RNAs play a crucial role in genome defense against transposable elements and guide Argonaute proteins to nascent RNA transcripts to induce co-transcriptional gene silencing. However, the molecular basis of this process remains unknown. Here, we identify the conserved RNA helicase Aquarius/EMB-4 as a direct and essential link between small RNA pathways and the transcriptional machinery in Caenorhabditis elegans. Aquarius physically interacts with the germline Argonaute HRDE-1. Aquarius is required to initiate small-RNA-induced heritable gene silencing. HRDE-1 and Aquarius silence overlapping sets of genes and transposable elements. Surprisingly, removal of introns from a target gene abolishes the requirement for Aquarius, but not HRDE-1, for small RNA-dependent gene silencing. We conclude that Aquarius allows small RNA pathways to compete for access to nascent transcripts undergoing co-transcriptional splicing in order to detect and silence transposable elements. Thus, Aquarius and HRDE-1 act as gatekeepers coordinating gene expression and genome defense. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Transposed-letter priming of prelexical orthographic representations.

PubMed

Kinoshita, Sachiko; Norris, Dennis

2009-01-01

A prime generated by transposing two internal letters (e.g., jugde) produces strong priming of the original word (judge). In lexical decision, this transposed-letter (TL) priming effect is generally weak or absent for nonword targets; thus, it is unclear whether the origin of this effect is lexical or prelexical. The authors describe the Bayesian Reader theory of masked priming (D. Norris & S. Kinoshita, 2008), which explains why nonwords do not show priming in lexical decision but why they do in the cross-case same-different task. This analysis is followed by 3 experiments that show that priming in this task is not based on low-level perceptual similarity between the prime and target, or on phonology, to make the case that priming is based on prelexical orthographic representation. The authors then use this task to demonstrate equivalent TL priming effects for nonwords and words. The results are interpreted as the first reliable evidence based on the masked priming procedure that letter position is not coded absolutely within the prelexical, orthographic representation. The implications of the results for current letter position coding schemes are discussed.

Physiological impact of transposable elements encoding DDE transposases in the environmental adaptation of Streptococcus agalactiae.

PubMed

Fléchard, Maud; Gilot, Philippe

2014-07-01

We have referenced and described Streptococcus agalactiae transposable elements encoding DDE transposases. These elements belonged to nine families of insertion sequences (ISs) and to a family of conjugative transposons (TnGBSs). An overview of the physiological impact of the insertion of all these elements is provided. DDE-transposable elements affect S. agalactiae in a number of aspects of its capability to adapt to various environments and modulate the expression of several virulence genes, the scpB-lmB genomic region and the genes involved in capsule expression and haemolysin transport being the targets of several different mobile elements. The referenced mobile elements modify S. agalactiae behaviour by transferring new gene(s) to its genome, by modifying the expression of neighbouring genes at the integration site or by promoting genomic rearrangements. Transposition of some of these elements occurs in vivo, suggesting that by dynamically regulating some adaptation and/or virulence genes, they improve the ability of S. agalactiae to reach different niches within its host and ensure the 'success' of the infectious process. © 2014 The Authors.

Population genetics and molecular evolution of DNA sequences in transposable elements. I. A simulation framework.

PubMed

Kijima, T E; Innan, Hideki

2013-11-01

A population genetic simulation framework is developed to understand the behavior and molecular evolution of DNA sequences of transposable elements. Our model incorporates random transposition and excision of transposable element (TE) copies, two modes of selection against TEs, and degeneration of transpositional activity by point mutations. We first investigated the relationships between the behavior of the copy number of TEs and these parameters. Our results show that when selection is weak, the genome can maintain a relatively large number of TEs, but most of them are less active. In contrast, with strong selection, the genome can maintain only a limited number of TEs but the proportion of active copies is large. In such a case, there could be substantial fluctuations of the copy number over generations. We also explored how DNA sequences of TEs evolve through the simulations. In general, active copies form clusters around the original sequence, while less active copies have long branches specific to themselves, exhibiting a star-shaped phylogeny. It is demonstrated that the phylogeny of TE sequences could be informative to understand the dynamics of TE evolution.

Classification of multipartite entanglement via negativity fonts

NASA Astrophysics Data System (ADS)

Sharma, S. Shelly; Sharma, N. K.

2012-04-01

Partial transposition of state operator is a well-known tool to detect quantum correlations between two parts of a composite system. In this paper, the global partial transpose (GPT) is linked to conceptually multipartite underlying structures in a state—the negativity fonts. If K-way negativity fonts with nonzero determinants exist, then selective partial transposition of a pure state, involving K of the N qubits (K⩽N), yields an operator with negative eigenvalues, identifying K-body correlations in the state. Expansion of GPT in terms of K-way partially transposed (KPT) operators reveals the nature of intricate intrinsic correlations in the state. Classification criteria for multipartite entangled states based on the underlying structure of global partial transpose of canonical state are proposed. The number of N-partite entanglement types for an N-qubit system is found to be 2N-1-N+2, while the number of major entanglement classes is 2N-1-1. Major classes for three- and four-qubit states are listed. Subclasses are determined by the number and type of negativity fonts in canonical states.

Character Decomposition and Transposition Processes of Chinese Compound Words in Rapid Serial Visual Presentation.

PubMed

Cao, Hong-Wen; Yang, Ke-Yu; Yan, Hong-Mei

2017-01-01

Character order information is encoded at the initial stage of Chinese word processing, however, its time course remains underspecified. In this study, we assess the exact time course of the character decomposition and transposition processes of two-character Chinese compound words (canonical, transposed, or reversible words) compared with pseudowords using dual-target rapid serial visual presentation (RSVP) of stimuli appearing at 30 ms per character with no inter-stimulus interval. The results indicate that Chinese readers can identify words with character transpositions in rapid succession; however, a transposition cost is involved in identifying transposed words compared to canonical words. In RSVP reading, character order of words is more likely to be reversed during the period from 30 to 180 ms for canonical and reversible words, but the period from 30 to 240 ms for transposed words. Taken together, the findings demonstrate that the holistic representation of the base word is activated, however, the order of the two constituent characters is not strictly processed during the very early stage of visual word processing.

Searching for non-transposable targets of planarian nuclear PIWI in pluripotent stem cells and differentiated cells.

PubMed

Kashima, Makoto; Agata, Kiyokazu; Shibata, Norito

2018-06-01

Nuclear PIWIs together with their guide RNAs (piRNAs) epigenetically silence various genes including transposons in many organisms. In planarians, the nuclear piwi family gene, DjpiwiB is specifically transcribed in adult pluripotent stem cells (adult PSC, neoblast), but not in differentiated cells. However, the protein accumulates in the nuclei of both neoblasts and their descendant differentiated cells. Interestingly, PIWI(DjPiwiB)-piRNA complexes are indispensable for the repression of transposable genes at the onset of differentiation from neoblasts. Here, we conducted a comparative transcriptome analysis between control and DjpiwiB(RNAi) animals to identify non-transposable target genes of the DjPiwiB-piRNA complexes. Using bioinformatic analyses and RNAi we demonstrate that DjPiwiB-piRNA complexes are required for the proper expression of Djmcm2 and Djhistone h4 in neoblasts and that DjPiwiB-piRNA complexes regulate the transient expression of Djcalu during neoblast differentiation. Thus, DjPiwiB-piRNA complexes regulate the correct expression patterns during neoblast self-renewal and differentiation. © 2018 Japanese Society of Developmental Biologists.

An efficient tensor transpose algorithm for multicore CPU, Intel Xeon Phi, and NVidia Tesla GPU

NASA Astrophysics Data System (ADS)

Lyakh, Dmitry I.

2015-04-01

An efficient parallel tensor transpose algorithm is suggested for shared-memory computing units, namely, multicore CPU, Intel Xeon Phi, and NVidia GPU. The algorithm operates on dense tensors (multidimensional arrays) and is based on the optimization of cache utilization on x86 CPU and the use of shared memory on NVidia GPU. From the applied side, the ultimate goal is to minimize the overhead encountered in the transformation of tensor contractions into matrix multiplications in computer implementations of advanced methods of quantum many-body theory (e.g., in electronic structure theory and nuclear physics). A particular accent is made on higher-dimensional tensors that typically appear in the so-called multireference correlated methods of electronic structure theory. Depending on tensor dimensionality, the presented optimized algorithms can achieve an order of magnitude speedup on x86 CPUs and 2-3 times speedup on NVidia Tesla K20X GPU with respect to the naïve scattering algorithm (no memory access optimization). The tensor transpose routines developed in this work have been incorporated into a general-purpose tensor algebra library (TAL-SH).

New Method of Filling of High-Temperature Fixed-Point Cells Based on Metal-Carbon Eutectics/Peritectics

NASA Astrophysics Data System (ADS)

Khlevnoy, B. B.; Grigoryeva, I. A.; Ibragimov, N. A.

2011-08-01

A new method of filling of high-temperature fixed-point cells based on metal-carbon eutectics and peritectics is suggested and tested. In this method a metal and carbon powder mixture is introduced not directly into the crucible, but into an additional container located just above the crucible. The mixture melts inside the container, and the already molten eutectic drops through a small hole in the bottom of the container and fills the crucible drop by drop. The method can be used to obtain a uniform ingot without porous or foundry cavities, to minimize the risk of contamination, and to avoid some other disadvantages. The method was applied to fabricate Re-C and WC-C cells using 5N purity materials. The cells demonstrated a good plateau shape with melting ranges of 0.2 K and 80 mK for Re-C and WC-C, respectively. The Re-C cell was compared with a cell built at NMIJ and showed good agreement with a difference of melting temperatures of only 45 mK.

Project Fog Drops. Part 1: Investigations of warm fog properties

NASA Technical Reports Server (NTRS)

Pilie, R. J.; Eadie, W.; Mack, E. J.; Rogers, C.; Kocmond, W. C.

1972-01-01

A detailed study was made of the micrometeorological and microphysical characteristics of eleven valley fogs occurring near Elmira, New York. Observations were made of temperature, dew point, wind speed and direction, dew deposition, vertical wind velocity, and net radiative flux. In fog, visibility was continuously recorded and periodic measurements were made of liquid water content and drop-size distribution. The observations were initiated in late evening and continued until the time of fog dissipation. The vertical distribution of temperature in the lowest 300 meters and cloud nucleus concentration at several heights were measured from an aircraft before fog nucleus concentrations at several heights were measured from an aircraft before fog formation. A numerical model was developed to investigate the life cycle of radiation fogs. The model predicts the temporal evolution of the vertical distributions of temperature, water vapor, and liquid water as determined by the turbulent transfer of heat and moisture. The model includes the nocturnal cooling of the earth's surface, dew formation, fog drop sedimentation, and the absorption of infrared radiation by fog.

Sooting Limits Of Microgravity Spherical Diffusion Flames. [conducted in the NASA Glenn 2.2-second drop tower

NASA Technical Reports Server (NTRS)

Sunderland, P. B.; Urban, D. L.; Stocker, D. P.; Chao, B.-H.; Axelbaum, Richard L.; Salzman, Jack (Technical Monitor)

2001-01-01

Limiting conditions for soot-particle inception were studied in microgravity spherical diffusion flames burning ethylene at atmospheric pressure. Nitrogen was supplied in the fuel and/or oxidizer to obtain the broadest range of stoichiometric mixture fraction. Both normal flames (oxygen in ambience) and inverted flames (fuel in ambience) were considered. Microgravity was obtained in the NASA Glenn 2.2-second drop tower. The flames were observed with a color video camera and sooting conditions were defined as conditions for which yellow emission was present throughout the duration of the drop. Sooting limit results were successfully correlated in terms of adiabatic flame temperature and stoichiometric mixture fraction. Soot free conditions were favored by increased stoichiometric mixture fractions. No statistically significant effect of convection direction on sooting limits was observed. The relationship between adiabatic flame temperature and stoichiometric mixture fraction at the sooting limits was found to be in qualitative agreement with a simple theory based on the assumption that soot inception can occur only where temperature and local C/O ratio exceed threshold values (circa 1250 K and 1, respectively).

Hydrogen retention in lithium and lithium oxide films

NASA Astrophysics Data System (ADS)

Buzi, L.; Yang, Y.; Domínguez-Gutiérrez, F. J.; Nelson, A. O.; Hofman, M.; Krstić, P. S.; Kaita, R.; Koel, B. E.

2018-04-01

Pure lithium (Li) surfaces are difficult to maintain in fusion devices due to rapid oxide formation, therefore, parameterizing and understanding the mechanisms of hydrogen (H, D) retention in lithium oxide (Li2O) in addition to pure Li is crucial for Li plasma-facing material applications. To compare H retention in Li and Li2O films, measurements were made as a function of surface temperature (90-520 K) under ultrahigh vacuum (UHV) conditions using temperature programmed desorption (TPD). In both cases, the total retention dropped with surface temperature, from 95% at 90 K to 35% at 520 K Li2O films retained H in similar amounts as pure Li. Molecular Dynamics (MD) modeling was used to elucidate the mechanisms of H retention, and results were consistent with experiments in terms of both retention fraction and the drop of retention with temperature.

Properties of Free-Machining Aluminum Alloys at Elevated Temperatures

NASA Astrophysics Data System (ADS)

Faltus, Jiří; Karlík, Miroslav; Haušild, Petr

In areas close to the cutting tool the workpieces being dry machined could be heated up to 350°C and they may be impact loaded. Therefore it is of interest to study mechanical properties of corresponding materials at elevated temperatures. Free-machining alloys of Al-Cu and Al-Mg-Si systems containing Pb, Bi and Sn additions (AA2011, AA2111B, AA6262, and AA6023) were subjected to Charpy U notch impact test at the temperatures ranging from 20 to 350°C. The tested alloys show a sharp drop in notch impact strength KU at different temperatures. This drop of KU is caused by liquid metal embrittlement due to the melting of low-melting point dispersed phases which is documented by differential scanning calorimetry. Fracture surfaces of the specimens were observed using a scanning electron microscope. At room temperature, the fractures of all studied alloys exhibited similar ductile dimple fracture micromorphology, at elevated temperatures, numerous secondary intergranular cracks were observed.

Contact angle of sessile drops in Lennard-Jones systems.

PubMed

Becker, Stefan; Urbassek, Herbert M; Horsch, Martin; Hasse, Hans

2014-11-18

Molecular dynamics simulations are used for studying the contact angle of nanoscale sessile drops on a planar solid wall in a system interacting via the truncated and shifted Lennard-Jones potential. The entire range between total wetting and dewetting is investigated by varying the solid-fluid dispersive interaction energy. The temperature is varied between the triple point and the critical temperature. A correlation is obtained for the contact angle in dependence of the temperature and the dispersive interaction energy. Size effects are studied by varying the number of fluid particles at otherwise constant conditions, using up to 150,000 particles. For particle numbers below 10,000, a decrease of the contact angle is found. This is attributed to a dependence of the solid-liquid surface tension on the droplet size. A convergence to a constant contact angle is observed for larger system sizes. The influence of the wall model is studied by varying the density of the wall. The effective solid-fluid dispersive interaction energy at a contact angle of θ = 90° is found to be independent of temperature and to decrease linearly with the solid density. A correlation is developed that describes the contact angle as a function of the dispersive interaction, the temperature, and the solid density. The density profile of the sessile drop and the surrounding vapor phase is described by a correlation combining a sigmoidal function and an oscillation term.

Characterization of Low Noise, Precision Voltage Reference REF5025-HT Under Extreme Temperatures

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad

2010-01-01

The performance of Texas Instruments precision voltage reference REF5025-HT was assessed under extreme temperatures. This low noise, 2.5 V output chip is suitable for use in high temperature down-hole drilling applications, but no data existed on its performance at cryogenic temperatures. The device was characterized in terms of output voltage and supply current at different input voltage levels as a function of temperature between +210 C and -190 C. Line and load regulation characteristics were also established at six load levels and at different temperatures. Restart capability at extreme temperatures and the effects of thermal cycling, covering the test temperature range, on its operation and stability were also investigated. Under no load condition, the voltage reference chip exhibited good stability in its output over the temperature range of -50 C to +200 C. Outside that temperature range, output voltage did change as temperature was changed. For example, at the extreme temperatures of +210 C and - 190 C, the output level dropped to 2.43 V and 2.32 V, respectively as compared to the nominal value of 2.5 V. At cryogenic test temperatures of -100 C and -150 C the output voltage dropped by about 20%. The quiescent supply current of the voltage reference varied slightly with temperature but remained close to its specified value. In terms of line regulation, the device exhibited excellent stability between -50 C and +150 C over the entire input voltage range and load levels. At the other test temperatures, however, while line regulation became poor at cryogenic temperatures of -100 C and below, it suffered slight degradation at the extreme high temperature but only at the high load level of 10 mA. The voltage reference also exhibited very good load regulation with temperature down to -100 C, but its output dropped sharply at +210 C only at the heavy load of 10 mA. The semiconductor chip was able restart at the extreme temperatures of -190 C and +210 C, and the limited thermal cycling did not influence its characteristics and had no impact on its packaging as no structural or physical damage was observed.

Low-Temperature Band Transport and Impact of Contact Resistance in Organic Field-Effect Transistors Based on Single-Crystal Films of Ph-BTBT-C10

NASA Astrophysics Data System (ADS)

Cho, Joung-min; Mori, Takehiko

2016-06-01

Transistors based on single-crystal films of 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) fabricated using the blade-coating method are investigated by the four-probe method down to low temperatures. The four-probe mobility is as large as 18 cm2/V s at room temperature, and increases to 45 cm2/V s at 80 K. At 60 K the two-probe mobility drops abruptly by about 50%, but the mobility drop is mostly attributed to the increase of the source resistance. The carrier transport in the present single-crystal film is regarded as essentially bandlike down to 30 K.

Germline Transformation of Drosophila Virilis Mediated by the Transposable Element Hobo

PubMed Central

Lozovskaya, E. R.; Nurminsky, D. I.; Hartl, D. L.; Sullivan, D. T.

1996-01-01

A laboratory strain of Drosophila virilis was genetically transformed with a hobo vector carrying the miniwhite cassette using a helper plasmid with an hsp70-driven hobo transposase-coding sequence. The rate of transformation was 0.5% per fertile G0 animal. Three transgenic insertions were cloned and characterized and found to be authentic hobo insertions. These results, together with the known wide-spread distribution of hobo in diverse insect species, suggest that hobo and related transposable elements may be of considerable utility in the germline transformation of insects other than D. melanogaster. PMID:8770594

Global Solutions to Repulsive Hookean Elastodynamics

NASA Astrophysics Data System (ADS)

Hu, Xianpeng; Masmoudi, Nader

2017-01-01

The global existence of classical solutions to the three dimensional repulsive Hookean elastodynamics around an equilibrium is considered. By linearization and Hodge's decomposition, the compressible part of the velocity, the density, and the compressible part of the transpose of the deformation gradient satisfy Klein-Gordon equations with speed {√{2}}, while the incompressible parts of the velocity and of the transpose of the deformation gradient satisfy wave equations with speed one. The space-time resonance method combined with the vector field method is used in a novel way to obtain the decay of the solution and hence global existence.

Transposable elements re-wire and fine-tune the transcriptome.

PubMed

Cowley, Michael; Oakey, Rebecca J

2013-01-01

What good are transposable elements (TEs)? Although their activity can be harmful to host genomes and can cause disease, they nevertheless represent an important source of genetic variation that has helped shape genomes. In this review, we examine the impact of TEs, collectively referred to as the mobilome, on the transcriptome. We explore how TEs-particularly retrotransposons-contribute to transcript diversity and consider their potential significance as a source of small RNAs that regulate host gene transcription. We also discuss a critical role for the mobilome in engineering transcriptional networks, permitting coordinated gene expression, and facilitating the evolution of novel physiological processes.

Operational Testing of Satellite based Hydrological Model (SHM)

NASA Astrophysics Data System (ADS)

Gaur, Srishti; Paul, Pranesh Kumar; Singh, Rajendra; Mishra, Ashok; Gupta, Praveen Kumar; Singh, Raghavendra P.

2017-04-01

Incorporation of the concept of transposability in model testing is one of the prominent ways to check the credibility of a hydrological model. Successful testing ensures ability of hydrological models to deal with changing conditions, along with its extrapolation capacity. For a newly developed model, a number of contradictions arises regarding its applicability, therefore testing of credibility of model is essential to proficiently assess its strength and limitations. This concept emphasizes to perform 'Hierarchical Operational Testing' of Satellite based Hydrological Model (SHM), a newly developed surface water-groundwater coupled model, under PRACRITI-2 program initiated by Space Application Centre (SAC), Ahmedabad. SHM aims at sustainable water resources management using remote sensing data from Indian satellites. It consists of grid cells of 5km x 5km resolution and comprises of five modules namely: Surface Water (SW), Forest (F), Snow (S), Groundwater (GW) and Routing (ROU). SW module (functions in the grid cells with land cover other than forest and snow) deals with estimation of surface runoff, soil moisture and evapotranspiration by using NRCS-CN method, water balance and Hragreaves method, respectively. The hydrology of F module is dependent entirely on sub-surface processes and water balance is calculated based on it. GW module generates baseflow (depending on water table variation with the level of water in streams) using Boussinesq equation. ROU module is grounded on a cell-to-cell routing technique based on the principle of Time Variant Spatially Distributed Direct Runoff Hydrograph (SDDH) to route the generated runoff and baseflow by different modules up to the outlet. For this study Subarnarekha river basin, flood prone zone of eastern India, has been chosen for hierarchical operational testing scheme which includes tests under stationary as well as transitory conditions. For this the basin has been divided into three sub-basins using three flow gauging sites as reference, viz., Muri, Jamshedpur and Ghatshila. Individual model set-up has been prepared for these sub-basins and calibration and validation using Split-sample test, first level of operational testing scheme is in progress. Subsequently for geographic transposability, Proxy-basin test will be done using Muri and Jamshedpur as proxy basins. Climatic transposability will be tested for dry and wet years using Differential split-sample test. For incorporating both geographic and climatic transposability Proxy-basin differential split sample test will be used. For quantitative evaluation of SHM, during Split-sample test Nash-Sutcliffe efficiency (NSE), Coefficient of Determination (R R^2)) and Percent BIAS (PBIAS) are being used. However, for transposability, a productive approach involving these performance measures, i.e. NSE*R R^2)*PBIAS will be used to decide the best value of parameters. Keywords: SHM, credibility, operational testing, transposability.

Leidenfrost drops on a heated liquid pool

NASA Astrophysics Data System (ADS)

Maquet, L.; Sobac, B.; Darbois-Texier, B.; Duchesne, A.; Brandenbourger, M.; Rednikov, A.; Colinet, P.; Dorbolo, S.

2016-09-01

We show that a volatile liquid drop placed at the surface of a nonvolatile liquid pool warmer than the boiling point of the drop can be held in a Leidenfrost state even for vanishingly small superheats. Such an observation points to the importance of the substrate roughness, negligible in the case considered here, in determining the threshold Leidenfrost temperature. A theoretical model based on the one proposed by Sobac et al. [Phys. Rev. E 90, 053011 (2014), 10.1103/PhysRevE.90.053011] is developed in order to rationalize the experimental data. The shapes of the drop and of the liquid substrate are analyzed. The model notably provides scalings for the vapor film thickness profile. For small drops, these scalings appear to be identical to the case of a Leidenfrost drop on a solid substrate. For large drops, in contrast, they are different, and no evidence of chimney formation has been observed either experimentally or theoretically in the range of drop sizes considered in this study. Concerning the evaporation dynamics, the radius is shown to decrease linearly with time whatever the drop size, which differs from the case of a Leidenfrost drop on a solid substrate. For high superheats, the characteristic lifetime of the drops versus the superheat follows a scaling law that is derived from the model, but, at low superheats, it deviates from this scaling by rather saturating.

When your baby or infant has a fever

MedlinePlus

... a child may even cause a rise in temperature. Regardless, you should report any fever in a ... normal. Most children will feel better when their temperature drops by even one degree. A lukewarm bath ...

Cool Shadow

NASA Image and Video Library

2013-10-17

The shadow of Saturn cuts across the rings as seen by NASA Cassini spacecraft. As the ring particles enter Saturn shadow, their temperature drops to even colder temperatures, only to warm back up again when they re-emerge into the sunlight.

Nitrogen stars: morphogenesis of a liquid drop

NASA Astrophysics Data System (ADS)

Strier, D. E.; Duarte, A. A.; Ferrari, H.; Mindlin, G. B.

2000-08-01

We report a study of a symmetry-breaking instability which ocurrs during the free evaporation of liquid nitrogen placed on a concave container initially at room temperature. The system evolves spontaneously from a highly disordered boiling state to one characterized by sequence of well-defined spatio-temporal structures. This sequence starts with the formation of a levitating drop. As the evaporation proceeds the drop undergoes an alternation between different star-like-shaped patterns with decreasing number of tips. In addition, each of this patterns oscillates. We frame the observed phenomena within the qualitative theory of bifurcations.

Predicting temperature drop rate of mass concrete during an initial cooling period using genetic programming

NASA Astrophysics Data System (ADS)

Bhattarai, Santosh; Zhou, Yihong; Zhao, Chunju; Zhou, Huawei

2018-02-01

Thermal cracking on concrete dams depends upon the rate at which the concrete is cooled (temperature drop rate per day) within an initial cooling period during the construction phase. Thus, in order to control the thermal cracking of such structure, temperature development due to heat of hydration of cement should be dropped at suitable rate. In this study, an attempt have been made to formulate the relation between cooling rate of mass concrete with passage of time (age of concrete) and water cooling parameters: flow rate and inlet temperature of cooling water. Data measured at summer season (April-August from 2009 to 2012) from recently constructed high concrete dam were used to derive a prediction model with the help of Genetic Programming (GP) software “Eureqa”. Coefficient of Determination (R) and Mean Square Error (MSE) were used to evaluate the performance of the model. The value of R and MSE is 0.8855 and 0.002961 respectively. Sensitivity analysis was performed to evaluate the relative impact on the target parameter due to input parameters. Further, testing the proposed model with an independent dataset those not included during analysis, results obtained from the proposed GP model are close enough to the real field data.

Inelastic deformation and damage at high temperature

NASA Astrophysics Data System (ADS)

Krempl, E.

1992-06-01

Combined experimental and theoretical investigations into the inelastic deformation and damage behavior of engineering alloys at elevated temperatures are being pursued. The analysis of previously performed strain rate change and relaxation tests on modified 9Cr-1Mo steel showed the need for inclusion of a recovery of state term in the growth laws for the state variables of the viscoplasticity theory based on overstress (VBO). Recovery of state terms were introduced and the experimental results were satisfactorily simulated. The finite deformation theory of VBO has been developed further to include a convected derivative rationale for the choice of the objective stress rate. The reversing direct current voltage drop measurements during low cycle fatigue at elevated temperature were improved. A passive filter bank and new positioning devices for the coils were installed. Tests at 650 C and lasting several days showed excessive, uncontrollable temperature changes. It was decided to drop the test temperature to 538 C which is close to the operating temperature of type 304 stainless steel. The temperature fluctuations in torsion tests were within +/- 3 C which was considered satisfactory.

Access to warm drinking water prevents rumen temperature drop without affecting in situ NDF disappearance in grazing winter range cows

USDA-ARS?s Scientific Manuscript database

Ingestion of large quantities of cold water or frozen forage may result in changes in temperature of ruminal contents. Rumen microorganisms may be sensitive to temperature changes in the ruminal environment. Therefore, this study was conducted to assess the variability in ruminal temperature and e...

Fluidic Sensor Temperature Indicating System.

DTIC Science & Technology

A fluidic sensor temperature indicating system designed by Honeywell Inc was tested on a T56 engine during dynamometer calibration. It was also...based on the sensor being mounted in a T56 engine showed a hot gas temperature drop from 1970F at the sensor entrance to 1760F in the sensor pulsation

Impact of temperature variation between adjacent days on childhood hand, foot and mouth disease during April and July in urban and rural Hefei, China

NASA Astrophysics Data System (ADS)

Cheng, Jian; Zhu, Rui; Xu, Zhiwei; Wu, Jinju; Wang, Xu; Li, Kesheng; Wen, Liying; Yang, Huihui; Su, Hong

2016-06-01

Previous studies have found that both high temperature and low temperature increase the risk of childhood hand, foot and mouth disease (HFMD). However, little is known about whether temperature variation between neighboring days has any effects on childhood HFMD. A Poisson generalized linear regression model, combined with a distributed lag non-linear model, was applied to examine the relationship between temperature change and childhood HFMD in Hefei, China, from 1st January 2010 to 31st December 2012. Temperature change was defined as the difference of current day's mean temperature and previous day's mean temperature. Late spring and early summer (April-July) were chosen as the main study period due to it having the highest childhood HFMD incidence. There was a statistical association between temperature change between neighboring days and childhood HFMD. The effects of temperature change on childhood HFMD increased below a temperature change of 0 °C (temperature drop). The temperature change has the greatest adverse effect on childhood HFMD at 7 days lag, with 4 % (95 % confidence interval 2-7 %) increase per 3 °C drop of temperature. Male children and urban children appeared to be more vulnerable to the effects of temperature change. Temperature change between adjacent days might be an alternative temperature indictor for exploring the temperature-HFMD relationship.

Impact of temperature variation between adjacent days on childhood hand, foot and mouth disease during April and July in urban and rural Hefei, China.

PubMed

Cheng, Jian; Zhu, Rui; Xu, Zhiwei; Wu, Jinju; Wang, Xu; Li, Kesheng; Wen, Liying; Yang, Huihui; Su, Hong

2016-06-01

Previous studies have found that both high temperature and low temperature increase the risk of childhood hand, foot and mouth disease (HFMD). However, little is known about whether temperature variation between neighboring days has any effects on childhood HFMD. A Poisson generalized linear regression model, combined with a distributed lag non-linear model, was applied to examine the relationship between temperature change and childhood HFMD in Hefei, China, from 1st January 2010 to 31st December 2012. Temperature change was defined as the difference of current day's mean temperature and previous day's mean temperature. Late spring and early summer (April-July) were chosen as the main study period due to it having the highest childhood HFMD incidence. There was a statistical association between temperature change between neighboring days and childhood HFMD. The effects of temperature change on childhood HFMD increased below a temperature change of 0 °C (temperature drop). The temperature change has the greatest adverse effect on childhood HFMD at 7 days lag, with 4 % (95 % confidence interval 2-7 %) increase per 3 °C drop of temperature. Male children and urban children appeared to be more vulnerable to the effects of temperature change. Temperature change between adjacent days might be an alternative temperature indictor for exploring the temperature-HFMD relationship.

Tnt1 Retrotransposon Mutagenesis: A Tool for Soybean Functional Genomics1[W][OA

PubMed Central

Cui, Yaya; Barampuram, Shyam; Stacey, Minviluz G.; Hancock, C. Nathan; Findley, Seth; Mathieu, Melanie; Zhang, Zhanyuan; Parrott, Wayne A.; Stacey, Gary

2013-01-01

Insertional mutagenesis is a powerful tool for determining gene function in both model and crop plant species. Tnt1, the transposable element of tobacco (Nicotiana tabacum) cell type 1, is a retrotransposon that replicates via an RNA copy that is reverse transcribed and integrated elsewhere in the plant genome. Based on studies in a variety of plants, Tnt1 appears to be inactive in normal plant tissue but can be reactivated by tissue culture. Our goal was to evaluate the utility of the Tnt1 retrotransposon as a mutagenesis strategy in soybean (Glycine max). Experiments showed that the Tnt1 element was stably transformed into soybean plants by Agrobacterium tumefaciens-mediated transformation. Twenty-seven independent transgenic lines carrying Tnt1 insertions were generated. Southern-blot analysis revealed that the copy number of transposed Tnt1 elements ranged from four to 19 insertions, with an average of approximately eight copies per line. These insertions showed Mendelian segregation and did not transpose under normal growth conditions. Analysis of 99 Tnt1 flanking sequences revealed insertions into 62 (62%) annotated genes, indicating that the element preferentially inserts into protein-coding regions. Tnt1 insertions were found in all 20 soybean chromosomes, indicating that Tnt1 transposed throughout the soybean genome. Furthermore, fluorescence in situ hybridization experiments validated that Tnt1 inserted into multiple chromosomes. Passage of transgenic lines through two different tissue culture treatments resulted in Tnt1 transposition, significantly increasing the number of insertions per line. Thus, our data demonstrate the Tnt1 retrotransposon to be a powerful system that can be used for effective large-scale insertional mutagenesis in soybean. PMID:23124322

Biased exonization of transposed elements in duplicated genes: A lesson from the TIF-IA gene.

PubMed

Amit, Maayan; Sela, Noa; Keren, Hadas; Melamed, Ze'ev; Muler, Inna; Shomron, Noam; Izraeli, Shai; Ast, Gil

2007-11-29

Gene duplication and exonization of intronic transposed elements are two mechanisms that enhance genomic diversity. We examined whether there is less selection against exonization of transposed elements in duplicated genes than in single-copy genes. Genome-wide analysis of exonization of transposed elements revealed a higher rate of exonization within duplicated genes relative to single-copy genes. The gene for TIF-IA, an RNA polymerase I transcription initiation factor, underwent a humanoid-specific triplication, all three copies of the gene are active transcriptionally, although only one copy retains the ability to generate the TIF-IA protein. Prior to TIF-IA triplication, an Alu element was inserted into the first intron. In one of the non-protein coding copies, this Alu is exonized. We identified a single point mutation leading to exonization in one of the gene duplicates. When this mutation was introduced into the TIF-IA coding copy, exonization was activated and the level of the protein-coding mRNA was reduced substantially. A very low level of exonization was detected in normal human cells. However, this exonization was abundant in most leukemia cell lines evaluated, although the genomic sequence is unchanged in these cancerous cells compared to normal cells. The definition of the Alu element within the TIF-IA gene as an exon is restricted to certain types of cancers; the element is not exonized in normal human cells. These results further our understanding of the delicate interplay between gene duplication and alternative splicing and of the molecular evolutionary mechanisms leading to genetic innovations. This implies the existence of purifying selection against exonization in single copy genes, with duplicate genes free from such constrains.

Biased exonization of transposed elements in duplicated genes: A lesson from the TIF-IA gene

PubMed Central

Amit, Maayan; Sela, Noa; Keren, Hadas; Melamed, Ze'ev; Muler, Inna; Shomron, Noam; Izraeli, Shai; Ast, Gil

2007-01-01

Background Gene duplication and exonization of intronic transposed elements are two mechanisms that enhance genomic diversity. We examined whether there is less selection against exonization of transposed elements in duplicated genes than in single-copy genes. Results Genome-wide analysis of exonization of transposed elements revealed a higher rate of exonization within duplicated genes relative to single-copy genes. The gene for TIF-IA, an RNA polymerase I transcription initiation factor, underwent a humanoid-specific triplication, all three copies of the gene are active transcriptionally, although only one copy retains the ability to generate the TIF-IA protein. Prior to TIF-IA triplication, an Alu element was inserted into the first intron. In one of the non-protein coding copies, this Alu is exonized. We identified a single point mutation leading to exonization in one of the gene duplicates. When this mutation was introduced into the TIF-IA coding copy, exonization was activated and the level of the protein-coding mRNA was reduced substantially. A very low level of exonization was detected in normal human cells. However, this exonization was abundant in most leukemia cell lines evaluated, although the genomic sequence is unchanged in these cancerous cells compared to normal cells. Conclusion The definition of the Alu element within the TIF-IA gene as an exon is restricted to certain types of cancers; the element is not exonized in normal human cells. These results further our understanding of the delicate interplay between gene duplication and alternative splicing and of the molecular evolutionary mechanisms leading to genetic innovations. This implies the existence of purifying selection against exonization in single copy genes, with duplicate genes free from such constrains. PMID:18047649

3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces

NASA Astrophysics Data System (ADS)

Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

2016-04-01

Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity.

3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces.

PubMed

Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

2016-04-04

Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity.

Direct Numerical Simulation of Transitional Multicomponent-Species Gaseous and Multicomponent-Liquid Drop-Laden Mixing

NASA Technical Reports Server (NTRS)

Selle, Laurent C.; Bellan, Josette

2006-01-01

A model of multicomponent-liquid (MC-liquid) drop evaporation in a three-dimensional mixing layer is here exercised at larger Reynolds numbers than in a previous study, and transitional states are obtained. The gas phase is followed in an Eulerian frame and the multitude of drops is described in a Lagrangian frame. Complete coupling between phases is included with source terms in the gas conservation equations accounting for the drop/flow interaction in terms of drop drag, drop heating and species evaporation. The liquid composition, initially specified as a single-Gamma (SG) probability distribution function (PDF) depending on the molar mass is allowed to evolve into a linear combination of two SGPDFs, called the double-Gamma PDF (DGPDF). The compositions of liquid and vapor emanating from the drops are calculated through four moments of the DGPDFs, which are drop-specific and location-specific, respectively. The mixing layer is initially excited to promote the double pairing of its four initial spanwise vortices into an ultimate vortex in which small scales proliferate. Simulations are performed for four liquids of different compositions and the effect of the initial mass loading and initial free-stream gas temperature are explored. For reference, Simulations are also performed for gaseous multicomponent mixing layers for which the effect of Reynolds number is investigated. The results encompass examination of the global layer characteristics, flow visualizations and homogeneous-plane statistics at transition. Comparisons are performed with previous pre-transitional MC-liquid simulations and with transitional single-component (SC) liquid studies. It is found that MCC flows at transition, the classical energy cascade is of similar strength, but that the smallest scales contain orders of magnitude less energy than SC flows, which is confirmed by the larger viscous dissipation in the former case. Contrasting to pre-transitional MC flows, the vorticity and drop organization depend on the initial gas temperature, this being due to the drop/turbulence coupling. The vapor-composition mean molar mass and standard deviation distributions strongly correlate with the initial liquid-composition PDF; such a correlation only exists for the magnitude of the mean but not for that of the standard deviation. Unlike in pre-transitional situations, regions of large composition standard deviation no longer necessarily coincide with regions of large mean molar mass. The kinetic energy, rotational and composition characteristics, and dissipation are liquid specific and the variation among liquids is amplified with increasing free-stream gas temperature. Eulerian and Lagrangian statistics of gas-phase quantities show that the different. Observation framework may affect the perception of the flow characteristics. The gas composition, of which the first four moments are calculated, is shown to be close to, but distinct from a SGPDF. The PDF of the scalar dissipation rate is calculated for drop-laden layers and is shown to depart more significantly from the typically assumed Gaussian in gaseous flows than experimentally measured gaseous scalar dissipation rates, this being attributed to the increased heterogeneity due to drop/flow interactions.

Alumina shunt for precooling a cryogen-free 4He or 3He refrigerator

NASA Astrophysics Data System (ADS)

Uhlig, Kurt

2016-10-01

In this technical report a cryogen-free 1 K cryostat is described where the pot of the 4He refrigeration unit is precooled by the 2nd stage of a pulse tube cryocooler (PTC) from room temperature to T ∼ 3 K via a shunt made from sintered alumina (SA); the total mass of the 1 K stage is 3.5 kg. SA has high thermal conductivity at high temperatures; but below ∼50 K the thermal conductivity drops rapidly, almost following a T3-law. This makes SA an interesting candidate for the construction of a thermal shunt, especially as the heat capacity of metals drops by several orders of magnitude in the temperature range from 300 K to 3 K. At the base temperature of the PTC, the heat conduction of the shunt is so small that the heat leak into the 1 K stage is negligible.

The effect of temperature on the discomfort caused by topical local anaesthesia.

PubMed Central

Callear, A B

1995-01-01

The warming of local anaesthetic solutions to reduce the pain felt on injection is common practice in a number of medical sub-specialties. A study was undertaken to assess the effect of temperature on the discomfort caused by local anaesthetic eye drops. Tropical anaesthetics amethocaine 1%, oxybuprocaine 0.4% and lignocaine 4% were studied, and after the application of strict exclusion criteria 60 patients were selected, 20 patients for each anaesthetic. Each patient group received a topical anaesthetic at 42 degrees C in one eye and at room temperature in the other. A 10 point visual analogue scale was used to assess the discomfort experienced. No statistically significant difference was found between the discomfort caused by drops at each temperature for any of the three anaesthetics studied. There appears no benefit in warming topical anaesthetic agents prior to their use. PMID:8786596

Hydrogen retention in lithium and lithium oxide films

DOE PAGES

Buzi, L.; Yang, Y.; Dominguez-Gutierrez, F. J.; ...

2018-02-09

Pure lithium (Li) surfaces are difficult to maintain in fusion devices due to rapid oxide formation, therefore, parameterizing and understanding the mechanisms of hydrogen (H, D) retention in lithium oxide (Li 2O) in addition to pure Li is crucial for Li plasma-facing material applications. To compare H retention in Li and Li 2O films, measurements were made as a function of surface temperature (90–520 K) under ultrahigh vacuum (UHV) conditions using temperature programmed desorption (TPD). In both cases, the total retention dropped with surface temperature, from 95% at 90 K to 35% at 520 K Li 2O films retained Hmore » in similar amounts as pure Li. Finally, Molecular Dynamics (MD) modeling was used to elucidate the mechanisms of H retention, and results were consistent with experiments in terms of both retention fraction and the drop of retention with temperature.« less

Hydrogen retention in lithium and lithium oxide films

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

Buzi, L.; Yang, Y.; Dominguez-Gutierrez, F. J.

Pure lithium (Li) surfaces are difficult to maintain in fusion devices due to rapid oxide formation, therefore, parameterizing and understanding the mechanisms of hydrogen (H, D) retention in lithium oxide (Li 2O) in addition to pure Li is crucial for Li plasma-facing material applications. To compare H retention in Li and Li 2O films, measurements were made as a function of surface temperature (90–520 K) under ultrahigh vacuum (UHV) conditions using temperature programmed desorption (TPD). In both cases, the total retention dropped with surface temperature, from 95% at 90 K to 35% at 520 K Li 2O films retained Hmore » in similar amounts as pure Li. Finally, Molecular Dynamics (MD) modeling was used to elucidate the mechanisms of H retention, and results were consistent with experiments in terms of both retention fraction and the drop of retention with temperature.« less

Thermal analysis of a multi-layer microchannel heat sink for cooling concentrator photovoltaic (CPV) cells

NASA Astrophysics Data System (ADS)

Siyabi, Idris Al; Shanks, Katie; Mallick, Tapas; Sundaram, Senthilarasu

2017-09-01

Concentrator Photovoltaic (CPV) technology is increasingly being considered as an alternative option for solar electricity generation. However, increasing the light concentration ratio could decrease the system output power due to the increase in the temperature of the cells. The performance of a multi-layer microchannel heat sink configuration was evaluated using numerical analysis. In this analysis, three dimensional incompressible laminar steady flow model was solved numerically. An electrical and thermal solar cell model was coupled for solar cell temperature and efficiency calculations. Thermal resistance, solar cell temperature and pumping power were used for the system efficiency evaluation. An increase in the number of microchannel layers exhibited the best overall performance in terms of the thermal resistance, solar cell temperature uniformity and pressure drop. The channel height and width has no effect on the solar cell maximum temperature. However, increasing channel height leads to a reduction in the pressure drop and hence less fluid pumping power.

Efficacy of intravenous fluid warming during goal-directed fluid therapy in patients undergoing laparoscopic colorectal surgery: a randomized controlled trial.

PubMed

Choi, Ji-Won; Kim, Duk-Kyung; Lee, Seung-Won; Park, Jung-Bo; Lee, Gyu-Hong

2016-06-01

To evaluate the clinical efficacy of intravenous (IV) fluid warming in patients undergoing laparoscopic colorectal surgery. Adult patients undergoing laparoscopic colorectal surgery were randomly assigned to receive either IV fluids at room temperature (control group) or warmed IV fluids (warm fluids group). Each patient received a standardized goal-directed fluid regimen based on stroke volume variances. Oesophageal temperature was measured at 15 min intervals for 2 h after induction of anaesthesia. A total of 52 patients were enrolled in the study. The drop in core temperature in the warm fluids group was significantly less than in the control group 2 h after the induction of anaesthesia. This significant difference was seen from 30 min after induction. IV fluid warming was associated with a smaller drop in core temperature than room temperature IV fluids in laparoscopic colorectal surgery incorporating goal-directed fluid therapy. © The Author(s) 2016.

Simulation on Thermocapillary-Driven Drop Coalescence by Hybrid Lattice Boltzmann Method

NASA Astrophysics Data System (ADS)

Xie, Haiqiong; Zeng, Zhong; Zhang, Liangqi; Yokota, Yuui; Kawazoe, Yoshiyuki; Yoshikawa, Akira

2016-04-01

A hybrid two-phase model, incorporating lattice Boltzmann method (LBM) and finite difference method (FDM), was developed to investigate the coalescence of two drops during their thermocapillary migration. The lattice Boltzmann method with a multi-relaxation-time (MRT) collision model was applied to solve the flow field for incompressible binary fluids, and the method was implemented in an axisymmetric form. The deformation of the drop interface was captured with the phase-field theory, and the continuum surface force model (CSF) was adopted to introduce the surface tension, which depends on the temperature. Both phase-field equation and the energy equation were solved with the finite difference method. The effects of Marangoni number and Capillary numbers on the drop's motion and coalescence were investigated.

Fluid flow inside and outside an evaporating sessile drop

NASA Astrophysics Data System (ADS)

Bouchenna, C.; Aitsaada, M.; Chikh, S.; Tadrist, L.

2017-11-01

The sessile drop evaporation is a phenomena which is extensively studied in the literature, but the governing effects are far from being well understood especially those involving movements taking place in both liquid and gas phases. The present work numerically studies the flow within and around an evaporating sessile drop. The flow is induced by the strong mass loss at contact line, the thermo-capillary effect and the buoyancy effect in the surrounding air. The results showed that buoyancy-induced flow in gas phase weakly influences thermo-capillarity-induced flow in the liquid phase. Buoyancy effect can strongly modify the temperature distribution at liquid-gas interface and thus the overall evaporation rate of the drop when the substrate is heated.

Undercooling measurement in a low-gravity containerless environment

NASA Technical Reports Server (NTRS)

Robinson, M. B.

1981-01-01

A technique is described for measuring the amount of undercooling for samples processed in a low-gravity containerless environment. The time of undercooling is determined by measuring the time of cooling before nucleation and recalescence by two infrared detectors. Once the cooling curve for each drop is calculated, the amount of undercooling can then be found. The technique is demonstrated by measuring the amount of undercooling for drops of pure niobium and select compositions of the niobium-germanium alloy system while free falling in a 32 n evacuated drop tube. The total hemispherical emissivities and specific heats for these materials were measured using a high-temperature containerless calorimeter. An overview of the effect of undercooling on drops of niobium and niobium-germanium is given.

The influence of flow modification on air and PCM temperatures in an accumulative heat exchanger

NASA Astrophysics Data System (ADS)

Borcuch, Marcin; Musiał, Michał; Sztekler, Karol; Kalawa, Wojciech; Gumuła, Stanisław; Stefański, Sebastian

2018-06-01

The paper presents the influence of flow modification on the operation of an accumulative heat exchanger. This device can be used as a regenerator in ventilation and air supply systems. A heat exchanger uses ceresine (a mixture of paraffins) as a phase change material (PCM). The aim of this research was to determine the effect of flow modification on temperature distribution and pressure drops in the device. The introduction contains a short description of the test stand used, including the accumulative heat exchanger, the guide vanes, and the locations of measurement and control equipment. We found that additional objects limited vortex structures, increased the inside temperature, and dropped the pressure along the heat exchanger. Guidelines for further research are proposed and briefly discussed.

Pressure dependence of the electrical properties of GaBi solidified in low gravity

NASA Technical Reports Server (NTRS)

Wu, M. K.; Ashburn, J. R.; Torng, C. J.; Curreri, P. A.; Chu, C. W.

1987-01-01

Immiscible GaBi alloys were solidified during free fall in the NASA Marshall Space Flight Center drop tower, which provides about 4.5 seconds of low gravity. The electrical resistivity and magnetic susceptibility were measured as a function of pressure (up to 18 kbar) and temperature (300 K to 4.2 K) of drop tower (DT) and ground control (GC) samples prepared under identical conditions, except for gravity. At ambient pressure the electrical resistance of the DT sample exhibits a broad maximum at 100 K, while that of GC sample decreases rapidly as temperature decreases. Both DT and GC samples become superconducting at 7.7 K. However, a minor second superconducting phase with a transition temperature at 8.3 K is observed only in the DT samples.

Susceptibility measurements on the superconducting properties of Nb-Ge alloys

NASA Technical Reports Server (NTRS)

Rathz, T. J.

1981-01-01

A susceptibility apparatus to measure superconducting properties of samples made in the MSFC Drop Tube was used to measure the transition temperature (Tc) and susceptibilities of Nb and Nb Ge Alloys prepared in bulk spherical (2-4 mm diameter) form using a 32 m drop tube in which containerless low gravity solidification could take place. Results indicate that a drop tube processing environment was beneficial for increasing the Tc of the superconducting phase of the material over that of arc melted material. The increase in Tc is found to be related to the amount of solidification of the total sample that took place before reaching the bottom of the drop tube. In phase and quadrature phase measurements of the specimen's susceptibility indicated that some improvement in homogeneity takes place in drop tube processing. These phase measurements also indicated little or no shielding of a lower Tc phase by a higher Tc filamentary structure.

Behavior of severely supercooled water drops impacting on superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Maitra, Tanmoy; Antonini, Carlo; Tiwari, Manish K.; Mularczyk, Adrian; Imeri, Zulkufli; Schoch, Philippe; Poulikakos, Dimos

2014-11-01

Surface icing, commonplace in nature and technology, has broad implications to daily life. To prevent surface icing, superhydrophobic surfaces/coatings with rationally controlled roughness features (both at micro and nano-scale) are considered to be a promising candidate. However, to fabricate/synthesize a high performance icephobic surface or coating, understanding the dynamic interaction between water and the surface during water drop impact in supercooled state is necessary. In this work, we investigate the water/substrate interaction using drop impact experiments down to -17°C. It is found that the resulting increased viscous effect of water at low temperature significantly affects all stages of drop dynamics such as maximum spreading, contact time and meniscus penetration into the superhydrophobic texture. Most interestingly, the viscous effect on the meniscus penetration into roughness feature leads to clear change in the velocity threshold for rebounding to sticking transition by 25% of supercooled drops. Swiss National Science Foundation (SNF) Grant 200021_135479.

The biology and evolution of transposable elements in parasites.

PubMed

Thomas, M Carmen; Macias, Francisco; Alonso, Carlos; López, Manuel C

2010-07-01

Transposable elements (TEs) are dynamic elements that can reshape host genomes by generating rearrangements with the potential to create or disrupt genes, to shuffle existing genes, and to modulate their patterns of expression. In the genomes of parasites that infect mammals several TEs have been identified that probably have been maintained throughout evolution due to their contribution to gene function and regulation of gene expression. This review addresses how TEs are organized, how they colonize the genomes of mammalian parasites, the functional role these elements play in parasite biology, and the interactions between these elements and the parasite genome. Copyright 2010 Elsevier Ltd. All rights reserved.

Revisiting the Relationship between Transposable Elements and the Eukaryotic Stress Response.

PubMed

Horváth, Vivien; Merenciano, Miriam; González, Josefa

2017-11-01

A relationship between transposable elements (TEs) and the eukaryotic stress response was suggested in the first publications describing TEs. Since then, it has often been assumed that TEs are activated by stress, and that this activation is often beneficial for the organism. In recent years, the availability of new high-throughput experimental techniques has allowed further interrogation of the relationship between TEs and stress. By reviewing the recent literature, we conclude that although there is evidence for a beneficial effect of TE activation under stress conditions, the relationship between TEs and the eukaryotic stress response is quite complex. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transposable Elements Re-Wire and Fine-Tune the Transcriptome

PubMed Central

Cowley, Michael; Oakey, Rebecca J.

2013-01-01

What good are transposable elements (TEs)? Although their activity can be harmful to host genomes and can cause disease, they nevertheless represent an important source of genetic variation that has helped shape genomes. In this review, we examine the impact of TEs, collectively referred to as the mobilome, on the transcriptome. We explore how TEs—particularly retrotransposons—contribute to transcript diversity and consider their potential significance as a source of small RNAs that regulate host gene transcription. We also discuss a critical role for the mobilome in engineering transcriptional networks, permitting coordinated gene expression, and facilitating the evolution of novel physiological processes. PMID:23358118

Transcriptional activity of transposable elements in coelacanth.

PubMed

Forconi, Mariko; Chalopin, Domitille; Barucca, Marco; Biscotti, Maria Assunta; De Moro, Gianluca; Galiana, Delphine; Gerdol, Marco; Pallavicini, Alberto; Canapa, Adriana; Olmo, Ettore; Volff, Jean-Nicolas

2014-09-01

The morphological stasis of coelacanths has long suggested a slow evolutionary rate. General genomic stasis might also imply a decrease of transposable elements activity. To evaluate the potential activity of transposable elements (TEs) in "living fossil" species, transcriptomic data of Latimeria chalumnae and its Indonesian congener Latimeria menadoensis were compared through the RNA-sequencing mapping procedures in three different organs (liver, testis, and muscle). The analysis of coelacanth transcriptomes highlights a significant percentage of transcribed TEs in both species. Major contributors are LINE retrotransposons, especially from the CR1 family. Furthermore, some particular elements such as a LF-SINE and a LINE2 sequences seem to be more expressed than other elements. The amount of TEs expressed in testis suggests possible transposition burst in incoming generations. Moreover, significant amount of TEs in liver and muscle transcriptomes were also observed. Analyses of elements displaying marked organ-specific expression gave us the opportunity to highlight exaptation cases, that is, the recruitment of TEs as new cellular genes, but also to identify a new Latimeria-specific family of Short Interspersed Nuclear Elements called CoeG-SINEs. Overall, transcriptome results do not seem to be in line with a slow-evolving genome with poor TE activity. © 2013 Wiley Periodicals, Inc.

LoRTE: Detecting transposon-induced genomic variants using low coverage PacBio long read sequences.

PubMed

Disdero, Eric; Filée, Jonathan

2017-01-01

Population genomic analysis of transposable elements has greatly benefited from recent advances of sequencing technologies. However, the short size of the reads and the propensity of transposable elements to nest in highly repeated regions of genomes limits the efficiency of bioinformatic tools when Illumina or 454 technologies are used. Fortunately, long read sequencing technologies generating read length that may span the entire length of full transposons are now available. However, existing TE population genomic softwares were not designed to handle long reads and the development of new dedicated tools is needed. LoRTE is the first tool able to use PacBio long read sequences to identify transposon deletions and insertions between a reference genome and genomes of different strains or populations. Tested against simulated and genuine Drosophila melanogaster PacBio datasets, LoRTE appears to be a reliable and broadly applicable tool to study the dynamic and evolutionary impact of transposable elements using low coverage, long read sequences. LoRTE is an efficient and accurate tool to identify structural genomic variants caused by TE insertion or deletion. LoRTE is available for download at http://www.egce.cnrs-gif.fr/?p=6422.

The processing of consonants and vowels during letter identity and letter position assignment in visual-word recognition: an ERP study.

PubMed

Vergara-Martínez, Marta; Perea, Manuel; Marín, Alejandro; Carreiras, Manuel

2011-09-01

Recent research suggests that there is a processing distinction between consonants and vowels in visual-word recognition. Here we conjointly examine the time course of consonants and vowels in processes of letter identity and letter position assignment. Event related potentials (ERPs) were recorded while participants read words and pseudowords in a lexical decision task. The stimuli were displayed under different conditions in a masked priming paradigm with a 50-ms SOA: (i) identity/baseline condition e.g., chocolate-CHOCOLATE); (ii) vowels-delayed condition (e.g., choc_l_te-CHOCOLATE); (iii) consonants-delayed condition (cho_o_ate-CHOCOLATE); (iv) consonants-transposed condition (cholocate-CHOCOLATE); (v) vowels-transposed condition (chocalote-CHOCOLATE), and (vi) unrelated condition (editorial-CHOCOLATE). Results showed earlier ERP effects and longer reaction times for the delayed-letter compared to the transposed-letter conditions. Furthermore, at early stages of processing, consonants may play a greater role during letter identity processing. Differences between vowels and consonants regarding letter position assignment are discussed in terms of a later phonological level involved in lexical retrieval. Copyright © 2010 Elsevier Inc. All rights reserved.

The role of transposable elements in health and diseases of the central nervous system.

PubMed

Reilly, Matthew T; Faulkner, Geoffrey J; Dubnau, Joshua; Ponomarev, Igor; Gage, Fred H

2013-11-06

First discovered in maize by Barbara McClintock in the 1940s, transposable elements (TEs) are DNA sequences that in some cases have the ability to move along chromosomes or "transpose" in the genome. This revolutionary finding was initially met with resistance by the scientific community and viewed by some as heretical. A large body of knowledge has accumulated over the last 60 years on the biology of TEs. Indeed, it is now known that TEs can generate genomic instability and reconfigure gene expression networks both in the germline and somatic cells. This review highlights recent findings on the role of TEs in health and diseases of the CNS, which were presented at the 2013 Society for Neuroscience meeting. The work of the speakers in this symposium shows that TEs are expressed and active in the brain, challenging the dogma that neuronal genomes are static and revealing that they are susceptible to somatic genomic alterations. These new findings on TE expression and function in the CNS have major implications for understanding the neuroplasticity of the brain, which could hypothetically have a role in shaping individual behavior and contribute to vulnerability to disease.

Does location uncertainty in letter position coding emerge because of literacy training?

PubMed

Perea, Manuel; Jiménez, María; Gomez, Pablo

2016-06-01

In the quest to unveil the nature of the orthographic code, a useful strategy is to examine the transposed-letter effect (e.g., JUGDE is more confusable with its base word, JUDGE, than the replacement-letter nonword JUPTE). A leading explanation of this phenomenon, which is line with models of visual attention, is that there is perceptual uncertainty at assigning letters ("objects") to positions. This mechanism would be at work not only with skilled readers but also with preliterate children. An alternative explanation is that the transposed-letter effect emerges at an orthographic level of processing as a direct consequence of literacy training. To test these accounts, we conducted a same-different matching experiment with preliterate 4-year-old children using same versus different trials (created by letter transposition or replacement). Results showed a significantly larger number of false positives (i.e., "same" responses) to transposed-letter strings than to 1/2 replacement-letter strings. Therefore, the present data favor the view that the visual processing of location information is inherently noisy and rule out an interpretation of confusability in letter position coding as emerging from literacy training. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Polymorphism and methylation patterns in Agave tequilana Weber var. 'Azul' plants propagated asexually by three different methods.

PubMed

Díaz-Martínez, Miriam; Nava-Cedillo, Alejandro; Guzmán-López, José Alfredo; Escobar-Guzmán, Rocío; Simpson, June

2012-04-01

Genetic variation in three forms of asexually propagated Agave tequilana Weber var. 'Azul' plants namely offsets, bulbils and in vitro cultured individuals was studied by AFLP analysis. Low levels of variation were observed between mother plants and offsets and a higher level between mother plant and bulbils. Families obtained from commercial plantations showed lower levels of variation in comparison to families grown as ornamentals. No variation was observed between the original explant and four generations of in vitro cultured plants. Epigenetic variation was also studied by analyzing changes in methylation patterns between mother plants and offspring in each form of asexual reproduction. Offsets and bulbils showed an overall decrease in methylation whereas in vitro cultured plants showed patterns specific to each generation: Generations 1 and 4 showed overall demethylation whereas Generations 2 and 3 showed increased methylation. Analysis of ESTs associated with transposable elements revealed higher proportions of ESTs from Ty1-copia-like, Gypsy and CACTA transposable elements in cDNA libraries obtained from pluripotent tissue suggesting a possible correlation between methylation patterns, expression of transposable element associated genes and somaclonal variation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Efficient transposition of the Tnt1 tobacco retrotransposon in the model legume Medicago truncatula.

PubMed

d'Erfurth, Isabelle; Cosson, Viviane; Eschstruth, Alexis; Lucas, Helene; Kondorosi, Adam; Ratet, P

2003-04-01

The tobacco element, Tnt1, is one of the few active retrotransposons in plants. Its transposition is activated during protoplast culture in tobacco and tissue culture in the heterologous host Arabidopsis thaliana. Here, we report its transposition in the R108 line of Medicago truncatula during the early steps of the in vitro transformation-regeneration process. Two hundred and twenty-five primary transformants containing Tnt1 were obtained. Among them, 11.2% contained only transposed copies of the element, indicating that Tnt1 transposed very early and efficiently during the in vitro transformation process, possibly even before the T-DNA integration. The average number of insertions per transgenic line was estimated to be about 15. These insertions were stable in the progeny and could be separated by segregation. Inspection of the sequences flanking the insertion sites revealed that Tnt1 had no insertion site specificity and often inserted in genes (one out of three insertions). Thus, our work demonstrates the functioning of an efficient transposable element in leguminous plants. These results indicate that Tnt1 can be used as a powerful tool for insertion mutagenesis in M. truncatula.

Formation and loss of large, unstable tandem arrays of the piggyBac transposable element in the yellow fever mosquito, Aedes aegypti.

PubMed

Adelman, Zach N; Jasinskiene, Nijole; Vally, K J M; Peek, Corrie; Travanty, Emily A; Olson, Ken E; Brown, Susan E; Stephens, Janice L; Knudson, Dennis L; Coates, Craig J; James, Anthony A

2004-10-01

The Class II transposable element, piggyBac, was used to transform the yellow fever mosquito, Aedes aegypti. In two transformed lines only 15-30% of progeny inherited the transgene, with these individuals displaying mosaic expression of the EGFP marker gene. Southern analyses, gene amplification of genomic DNA, and plasmid rescue experiments provided evidence that these lines contained a high copy number of piggyBac transformation constructs and that much of this DNA consisted of both donor and helper plasmids. A detailed analysis of one line showed that the majority of piggyBac sequences were unit-length donor or helper plasmids arranged in a large tandem array that could be lost en masse in a single generation. Despite the presence of a transposase source and many intact donor elements, no conservative (cut and paste) transposition of piggyBac was observed in these lines. These results reveal one possible outcome of uncontrolled and/or unexpected recombination in this mosquito, and support the conclusion that further investigation is necessary before transposable elements such as piggyBac can be used as genetic drive mechanisms to move pathogen-resistance genes into mosquito populations.

An efficient tensor transpose algorithm for multicore CPU, Intel Xeon Phi, and NVidia Tesla GPU

DOE PAGES

Lyakh, Dmitry I.

2015-01-05

An efficient parallel tensor transpose algorithm is suggested for shared-memory computing units, namely, multicore CPU, Intel Xeon Phi, and NVidia GPU. The algorithm operates on dense tensors (multidimensional arrays) and is based on the optimization of cache utilization on x86 CPU and the use of shared memory on NVidia GPU. From the applied side, the ultimate goal is to minimize the overhead encountered in the transformation of tensor contractions into matrix multiplications in computer implementations of advanced methods of quantum many-body theory (e.g., in electronic structure theory and nuclear physics). A particular accent is made on higher-dimensional tensors that typicallymore » appear in the so-called multireference correlated methods of electronic structure theory. Depending on tensor dimensionality, the presented optimized algorithms can achieve an order of magnitude speedup on x86 CPUs and 2-3 times speedup on NVidia Tesla K20X GPU with respect to the na ve scattering algorithm (no memory access optimization). Furthermore, the tensor transpose routines developed in this work have been incorporated into a general-purpose tensor algebra library (TAL-SH).« less

SRSF3 maintains transcriptome integrity in oocytes by regulation of alternative splicing and transposable elements.

PubMed

Do, Dang Vinh; Strauss, Bernhard; Cukuroglu, Engin; Macaulay, Iain; Wee, Keng Boon; Hu, Tim Xiaoming; Igor, Ruiz De Los Mozos; Lee, Caroline; Harrison, Andrew; Butler, Richard; Dietmann, Sabine; Jernej, Ule; Marioni, John; Smith, Christopher W J; Göke, Jonathan; Surani, M Azim

2018-01-01

The RNA-binding protein SRSF3 (also known as SRp20) has critical roles in the regulation of pre-mRNA splicing. Zygotic knockout of Srsf3 results in embryo arrest at the blastocyst stage. However, SRSF3 is also present in oocytes, suggesting that it might be critical as a maternally inherited factor. Here we identify SRSF3 as an essential regulator of alternative splicing and of transposable elements to maintain transcriptome integrity in mouse oocyte. Using 3D time-lapse confocal live imaging, we show that conditional deletion of Srsf3 in fully grown germinal vesicle oocytes substantially compromises the capacity of germinal vesicle breakdown (GVBD), and consequently entry into meiosis. By combining single cell RNA-seq, and oocyte micromanipulation with steric blocking antisense oligonucleotides and RNAse-H inducing gapmers, we found that the GVBD defect in mutant oocytes is due to both aberrant alternative splicing and derepression of B2 SINE transposable elements. Together, our study highlights how control of transcriptional identity of the maternal transcriptome by the RNA-binding protein SRSF3 is essential to the development of fertilized-competent oocytes.

Making things difficult in lexical decision: the impact of pseudohomophones and transposed-letter nonwords on frequency and semantic priming effects.

PubMed

Lupker, Stephen J; Pexman, Penny M

2010-09-01

Performance in a lexical decision task is crucially dependent on the difficulty of the word-nonword discrimination. More wordlike nonwords cause not only a latency increase for words but also, as reported by Stone and Van Orden (1993), larger word frequency effects. Several current models of lexical decision making can explain these types of results in terms of a single mechanism, a mechanism driven by the nature of the interactions within the lexicon. In 2 experiments, we replicated Stone and Van Orden's increased frequency effect using both pseudohomophones (e.g., BEEST) and transposed-letter nonwords (e.g., JUGDE) as the more wordlike nonwords. In a 3rd experiment, we demonstrated that simply increasing word latencies without changing the difficulty of the word-nonword discrimination does not produce larger frequency effects. These results are reasonably consistent with many current models. In contrast, neither pseudohomophones nor transposed-letter nonwords altered the size of semantic priming effects across 4 additional experiments, posing a challenge to models that would attempt to explain both nonword difficulty effects and semantic priming effects in lexical decision tasks in terms of a single, lexically driven mechanism. (c) 2010 APA, all rights reserved).

Development of a Bone-Conducted Ultrasonic Hearing Aid for the Profoundly Deaf: Evaluation of Sound Quality Using a Semantic Differential Method

NASA Astrophysics Data System (ADS)

Nakagawa, Seiji; Fujiyuki, Chika; Kagomiya, Takayuki

2013-07-01

Bone-conducted ultrasound (BCU) is perceived even by the profoundly sensorineural deaf. A novel hearing aid using the perception of amplitude-modulated BCU (BCU hearing aid: BCUHA) has been developed. However, there is room for improvement particularly in terms of sound quality. BCU speech is accompanied by a strong high-pitched tone and contain some distortion. In this study, the sound quality of BCU speech with several types of amplitude modulation [double-sideband with transmitted carrier (DSB-TC), double-sideband with suppressed carrier (DSB-SC), and transposed modulations] and air-conducted (AC) speech was quantitatively evaluated using semantic differential and factor analysis. The results showed that all the types of BCU speech had higher metallic and lower esthetic factor scores than AC speech. On the other hand, transposed speech was closer than the other types of BCU speech to AC speech generally; the transposed speech showed a higher powerfulness factor score than the other types of BCU speech and a higher esthetic factor score than DSB-SC speech. These results provide useful information for further development of the BCUHA.

How does interhemispheric communication in visual word recognition work? Deciding between early and late integration accounts of the split fovea theory.

PubMed

Van der Haegen, Lise; Brysbaert, Marc; Davis, Colin J

2009-02-01

It has recently been shown that interhemispheric communication is needed for the processing of foveally presented words. In this study, we examine whether the integration of information happens at an early stage, before word recognition proper starts, or whether the integration is part of the recognition process itself. Two lexical decision experiments are reported in which words were presented at different fixation positions. In Experiment 1, a masked form priming task was used with primes that had two adjacent letters transposed. The results showed that although the fixation position had a substantial influence on the transposed letter priming effect, the priming was not smaller when the transposed letters were sent to different hemispheres than when they were projected to the same hemisphere. In Experiment 2, stimuli were presented that either had high frequency hemifield competitors or could be identified unambiguously on the basis of the information in one hemifield. Again, the lexical decision times did not vary as a function of hemifield competitors. These results are consistent with the early integration account, as presented in the SERIOL model of visual word recognition.

Modulating signaling networks by CRISPR/Cas9-mediated transposable element insertion.

PubMed

Vaschetto, Luis María

2018-04-01

In a recent past, transposable elements (TEs) were referred to as selfish genetic components only capable of copying themselves with the aim of increasing the odds of being inherited. Nonetheless, TEs have been initially proposed as positive control elements acting in synergy with the host. Nowadays, it is well known that TE movement into host genome comprises an important evolutionary mechanism capable of increasing the adaptive fitness. As insights into TE functioning are increasing day to day, the manipulation of transposition has raised an interesting possibility of setting the host functions, although the lack of appropriate genome engineering tools has unpaved it. Fortunately, the emergence of genome editing technologies based on programmable nucleases, and especially the arrival of a multipurpose RNA-guided Cas9 endonuclease system, has made it possible to reconsider this challenge. For such purpose, a particular type of transposons referred to as miniature inverted-repeat transposable elements (MITEs) has shown a series of interesting characteristics for designing functional drivers. Here, recent insights into MITE elements and versatile RNA-guided CRISPR/Cas9 genome engineering system are given to understand how to deploy the potential of TEs for control of the host transcriptional activity.

Determination analaysis of the power losses of transformers with continuously transpored conductors (CTC) based fuzzy logic

NASA Astrophysics Data System (ADS)

Kaloko, Bambang Sri; Atsari, Erinna Dyah

2017-03-01

Electric motive force which flows into the iron core continuously on a plate - plate iron isolated may cause heat posed by current eddy (eddy current). No water loss occurs due to detainees on the circuit at the the flow of current load because this loss happened on the entanglement of the transformer is made of copper. Continuously Transposed Conductors (CTC) consist of a number of enameled rectangular wires (5-84 strands) made into an assembly. Each strand is transposed in turn to each position in the cable and is then covered with layers of insulation paper. Continuously Transposed Conductors are used in winding wires for medium and ultra high power transformers. CTC is manufactured by OFHC copper and indeed, is able to supply polyester roped. CTC which has been designed to reduce production cost, oil pocket and improve cooling efficiency. Hardened type CTC (CPR1, CPR2, and CPR3: BS1432) and Self-bonding CTC which can be used to improve mechanical and electrical strength are also available. This analysis is performed using the methods of fuzzy logic in taking account of the resources.

Measurement of Surface Interfacial Tension as a Function of Temperature Using Pendant Drop Images

NASA Astrophysics Data System (ADS)

Yakhshi-Tafti, Ehsan; Kumar, Ranganathan; Cho, Hyoung J.

2011-10-01

Accurate and reliable measurements of surface tension at the interface of immiscible phases are crucial to understanding various physico-chemical reactions taking place between those. Based on the pendant drop method, an optical (graphical)-numerical procedure was developed to determine surface tension and its dependency on the surrounding temperature. For modeling and experimental verification, chemically inert and thermally stable perfluorocarbon (PFC) oil and water was used. Starting with geometrical force balance, governing equations were derived to provide non-dimensional parameters which were later used to extract values for surface tension. Comparative study verified the accuracy and reliability of the proposed method.

Improved Comfort | Efficient Windows Collaborative

Science.gov Websites

temperature; how low the glass temperature drops depends on the window's insulating quality. If people are exposed to the effects of a cold surface, they can experience significant radiant heat loss to that cold surface and they feel uncomfortable, even if the room air temperature is comfortable. When the interior

76 FR 9449 - National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-17

... chemistry, scrubber pressure drop, and scrubber inlet gas temperature hourly. The final rule does not... pressure) and inlet gas temperature to be based on the minimum flow rate (or line pressure) or maximum inlet gas temperature established during the initial performance test. It also includes two additional...

Co-pyrolysis of rice straw and Polyethylene Terephthalate (PET) using a fixed bed drop type pyrolyzer

NASA Astrophysics Data System (ADS)

Izzatie, N. I.; Basha, M. H.; Uemura, Y.; Hashim, M. S. M.; Amin, N. A. M.; Hamid, M. F.

2017-10-01

In this work, co-pyrolysis of rice straw and polyethylene terephthalate (PET) was carried out at different temperatures (450,500,550, and 600°C) at ratio 1:1 by using fixed bed drop-type pyrolyzer. The purpose of this work is to determine the effect of pyrolysis temperature on the product yield. As the temperature increased, the pyrolysis oil increased until it reaches certain high temperature (600°C), the pyrolysis oil decreased as of more NCG were produced. The temperature 550°C is considered as the optimum pyrolysis temperature since it produced the highest amount of pyrolysis oil with 36 wt.%. In pyrolysis oil, the calorific value (13.98kJ/g) was low because of the presence of high water content (52.46 wt.%). Main chemicals group from pyrolysis oil were an aldehyde, ketones, acids, aromatics, and phenol and all compound have abundant of hydrogen and carbon were identified. Co-pyrolysis of rice straw and PET produced a higher amount of carbon oxides and recycling back the NCG could increase liquid and char yields.

The millennium water vapour drop in chemistry-climate model simulations

NASA Astrophysics Data System (ADS)

Brinkop, Sabine; Dameris, Martin; Jöckel, Patrick; Garny, Hella; Lossow, Stefan; Stiller, Gabriele

2016-07-01

This study investigates the abrupt and severe water vapour decline in the stratosphere beginning in the year 2000 (the "millennium water vapour drop") and other similarly strong stratospheric water vapour reductions by means of various simulations with the state-of-the-art Chemistry-Climate Model (CCM) EMAC (ECHAM/MESSy Atmospheric Chemistry Model). The model simulations differ with respect to the prescribed sea surface temperatures (SSTs) and whether nudging is applied or not. The CCM EMAC is able to most closely reproduce the signature and pattern of the water vapour drop in agreement with those derived from satellite observations if the model is nudged. Model results confirm that this extraordinary water vapour decline is particularly obvious in the tropical lower stratosphere and is related to a large decrease in cold point temperature. The drop signal propagates under dilution to the higher stratosphere and to the poles via the Brewer-Dobson circulation (BDC). We found that the driving forces for this significant decline in water vapour mixing ratios are tropical sea surface temperature (SST) changes due to a coincidence with a preceding strong El Niño-Southern Oscillation event (1997/1998) followed by a strong La Niña event (1999/2000) and supported by the change of the westerly to the easterly phase of the equatorial stratospheric quasi-biennial oscillation (QBO) in 2000. Correct (observed) SSTs are important for triggering the strong decline in water vapour. There are indications that, at least partly, SSTs contribute to the long period of low water vapour values from 2001 to 2006. For this period, the specific dynamical state of the atmosphere (overall atmospheric large-scale wind and temperature distribution) is important as well, as it causes the observed persistent low cold point temperatures. These are induced by a period of increased upwelling, which, however, has no corresponding pronounced signature in SSTs anomalies in the tropics. Our free-running simulations do not capture the drop as observed, because a) the cold point temperature has a low bias and thus the water vapour variability is reduced and b) because they do not simulate the appropriate dynamical state. Large negative water vapour declines are also found in other years and seem to be a feature which can be found after strong combined El Niño/La Niña events if the QBO west phase during La Niña changes to the east phase.

The role of natural mineral particles collected at one site in Patagonia as immersion freezing ice nuclei

NASA Astrophysics Data System (ADS)

López, María Laura; Borgnino, Laura; Ávila, Eldo E.

2018-05-01

This work studies the role of mineral particles collected in the region of Patagonia (Neuquén, Argentina) as ice nuclei particles (INPs) by immersion freezing mode. The particle immersion-freezing ability was analyzed under laboratory conditions by using an established drop-freezing technique. Mineralogical composition was characterized by using X-ray diffraction and electron micro probe analysis. Dynamic light scattering was used to determine the grain size distribution of particles, while the N2 adsorption and methylene blue adsorption methods were applied to determine their specific surface area. Water droplets of different volumes containing different concentrations of particles were cooled until droplets were frozen. For all the analyzed drop volumes, an increase in the freezing temperature of the drops was observed with increasing dust concentration. In the same way, the freezing temperature increased when the drop volume was increased at constant dust concentration. Both behaviors were linked to the availability of active sites in the particles. A plateau in the freezing temperature was observed at high suspension concentration for all the drop volumes. This plateau was related to the aggregation of the particles when the suspension concentration was increased and to the consequent decrease in the number of active sites. The active sites per unit of surface area were calculated and reported. For the studied range of temperature, results are in agreement with those reported for different sites and particles. From the chemical and morphological analysis of the particle components and the results obtained from the literature, it was concluded that even though montmorillonite was the main mineral in the collected sample, the accessory minerals deserve to be analyzed in detail in order to know if they could be responsible for the ability of the collected soil particles to act as INPs. Considering that the region of Patagonia has been identified as an important source of natural mineral particles in the atmosphere, it is important to analyze the ability of these particles to act as INP. As far as we know, this is the first study carrying out this investigation.

Measurement of Bitumen Viscosity in a Room-Temperature Drop Experiment: Student Education, Public Outreach and Modern Science in One

ERIC Educational Resources Information Center

Widdicombe, A. T.; Ravindrarajah, P.; Sapelkin, A.; Phillips, A. E.; Dunstan, D.; Dove, M. T.; Brazhkin, V. V.; Trachenko, K.

2014-01-01

The slow flow of a viscous liquid is a thought-provoking experiment that challenges students, academics and the public to think about some fundamental questions in modern science. In the Queensland demonstration--the world's longest-running experiment, which has earned the Ig Nobel prize--one drop of pitch takes about ten years to fall, leading to…

3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces

PubMed Central

Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

2016-01-01

Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity. PMID:27040483

A model of the evaporation of binary-fuel clusters of drops

NASA Technical Reports Server (NTRS)

Harstad, K.; Bellan, J.

1991-01-01

A formulation has been developed to describe the evaporation of dense or dilute clusters of binary-fuel drops. The binary fuel is assumed to be made of a solute and a solvent whose volatility is much lower than that of the solute. Convective flow effects, inducing a circulatory motion inside the drops, are taken into account, as well as turbulence external to the cluster volume. Results obtained with this model show that, similar to the conclusions for single isolated drops, the evaporation of the volatile is controlled by liquid mass diffusion when the cluster is dilute. In contrast, when the cluster is dense, the evaporation of the volatile is controlled by surface layer stripping, that is, by the regression rate of the drop, which is in fact controlled by the evaporation rate of the solvent. These conclusions are in agreement with existing experimental observations. Parametric studies show that these conclusions remain valid with changes in ambient temperature, initial slip velocity between drops and gas, initial drop size, initial cluster size, initial liquid mass fraction of the solute, and various combinations of solvent and solute. The implications of these results for computationally intensive combustor calculations are discussed.

Numerical simulation on the powder propellant pickup characteristics of feeding system at high pressure

NASA Astrophysics Data System (ADS)

Sun, Haijun; Hu, Chunbo; Zhu, Xiaofei

2017-10-01

A numerical study of powder propellant pickup progress at high pressure was presented in this paper by using two-fluid model with kinetic theory of granular flow in the computational fluid dynamics software package ANSYS/Fluent. Simulations were conducted to evaluate the effects of initial pressure, initial powder packing rate and mean particle diameter on the flow characteristics in terms of velocity vector distribution, granular temperature, pressure drop, particle velocity and volume. The numerical results of pressure drop were also compared with experiments to verify the TFM model. The simulated results show that the pressure drop value increases as the initial pressure increases, and the granular temperature under the conditions of different initial pressures and packing rates is almost the same in the area of throttling orifice plate. While there is an appropriate value for particle size and packing rate to form a ;core-annulus; structure in powder box, and the time-averaged velocity vector distribution of solid phase is inordinate.

Experimental study of the effect of cycle pressure on lean combustion emissions

NASA Technical Reports Server (NTRS)

Roffe, G.; Venkataramani, K. S.

1978-01-01

Experiments were conducted in which a stream of premixed propane and air was burned under conditions representative of gas turbine operation. Emissions of NOx, CO, and unburned hydrocarbons (UHC) were measured over a range of combustor inlet temperature, pressure, and residence time at equivalence ratios from 0.7 down to the lean stability limit. At an inlet temperature of 600 K, observed NOx levels dropped markedly with decreasing pressure for pressures below 20 atm. The NOx levels are proportional to combustor residence time and formation rates were principally a function of adiabatic flame temperature. For adiabatic flame temperatures of 2050 K and higher, CO reached chemical equilibrium within 2 msec. Unburned hydrocarbon species dropped to a negligible level within 2 msec regardless of inlet temperature, pressure, or equivalence ratio. For a combustor residence time of 2.5 msec, combustion inefficiency became less than 0.01% at an adiabatic flame temperature of 2050 K. The maximum combustion inefficiency observed was on the order of 1% and corresponded to conditions near the lean stability limit. Using a perforated plate flameholder, this limit is well represented by the condition of 1800 K adiabatic flame temperature.

On-sun testing of an advanced falling particle receiver system

NASA Astrophysics Data System (ADS)

Ho, Clifford K.; Christian, Joshua M.; Yellowhair, Julius; Siegel, Nathan; Jeter, Sheldon; Golob, Matthew; Abdel-Khalik, Said I.; Nguyen, Clayton; Al-Ansary, Hany

2016-05-01

A 1 MWth high-temperature falling particle receiver was constructed and tested at the National Solar Thermal Test Facility at Sandia National Laboratories. The continuously recirculating system included a particle elevator, top and bottom hoppers, and a cavity receiver that comprised a staggered array of porous chevron-shaped mesh structures that slowed the particle flow through the concentrated solar flux. Initial tests were performed with a peak irradiance of ~300 kW/m2 and a particle mass flow rate of 3.3 kg/s. Peak particle temperatures reached over 700 °C near the center of the receiver, but the particle temperature increase near the sides was lower due to a non-uniform irradiance distribution. At a particle inlet temperature of ~440 °C, the particle temperature increase was 27 °C per meter of drop length, and the thermal efficiency was ~60% for an average irradiance of 110 kW/m2. At an average irradiance of 211 kW/m2, the particle temperature increase was 57.1 °C per meter of drop length, and the thermal efficiency was ~65%. Tests with higher irradiances are being performed and are expected to yield greater particle temperature increases and efficiencies.

Superconducting phase transitions in mK temperature range in splat-cooled U0.85Pt0.15 alloys

NASA Astrophysics Data System (ADS)

Kim-Ngan, N.-T. H.; Tarnawski, Z.; Chrobak, M.; Sowa, S.; Duda, A.; Paukov, M.; Buturlim, V.; Havela, L.

2018-05-01

We present the temperature and magnetic-field dependence of the electrical resistivity (ρ(T,B)) in the mK temperature range used as a diagnostic tool for the superconductivity of U-Pt alloys prepared by splat-cooling technique. In most of the investigated alloys, a single resistivity drop was observed at the superconducting transition. For splat-cooled U0.85Pt0.15 (U-15 at% Pt) alloys, two drops were revealed around 0.6 K and 1 K tentatively attributed to the superconducting phase transitions of the γ-U phase and α-U phase. The ρ(T,B) characteristics were found to depend on the cooling rate. The superconductivity is characterized by very high upper critical fields, reaching 4.5 T in the 0 K limit.

Method and apparatus for generating microshells of refractory materials

NASA Technical Reports Server (NTRS)

Lee, Mark C. (Inventor); Schilling, Christopher (Inventor); Ladner, Jr., George O. (Inventor); Wang, Taylor G. (Inventor)

1987-01-01

A system is described for forming accurately spherical and centered fluid-filled shells, especially of high melting temperature material. Material which is to form the shells is placed in a solid form in a container, and the material is rapidly heated to a molten temperature to avoid recrystallization and the possible generation of unwanted microbubbles in the melt. Immediately after the molten shells are formed, they drop through a drop tower whose upper end is heated along a distance of at least one foot to provide time for dissipation of surface waves on the shells while they cool to a highly viscous, or just above melting temperature so that the bubble within the shell will not rise and become off centered. The rest of the tower is cryogenically cooled to cool the shell to a solid state.

Study of nitrogen two-phase flow pressure drop in horizontal and vertical orientation

NASA Astrophysics Data System (ADS)

Koettig, T.; Kirsch, H.; Santandrea, D.; Bremer, J.

2017-12-01

The large-scale liquid argon Short Baseline Neutrino Far-detector located at Fermilab is designed to detect neutrinos allowing research in the field of neutrino oscillations. It will be filled with liquid argon and operate at almost ambient pressure. Consequently, its operation temperature is determined at about 87 K. The detector will be surrounded by a thermal shield, which is actively cooled with boiling nitrogen at a pressure of about 2.8 bar absolute, the respective saturation pressure of nitrogen. Due to strict temperature gradient constraints, it is important to study the two-phase flow pressure drop of nitrogen along the cooling circuit of the thermal shield in different orientations of the flow with respect to gravity. An experimental setup has been built in order to determine the two-phase flow pressure drop in nitrogen in horizontal, vertical upward and vertical downward direction. The measurements have been conducted under quasi-adiabatic conditions and at a saturation pressure of 2.8 bar absolute. The mass velocity has been varied in the range of 20 kg·m-2·s-1 to 70 kg·m-2·s-1 and the pressure drop data has been recorded scanning the two-phase region from vapor qualities close to zero up to 0.7. The experimental data will be compared with several established predictions of pressure drop e.g. Mueller-Steinhagen and Heck by using the void fraction correlation of Rouhani.

MEASUREMENT OF THE HIGH-FIELD Q-DROP IN A LARGE-GRAIN NIOBIUM CAVITY FOR DIFFERENT OXIDATION PROCESSES

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

Gianluigi Ciovati; Peter Kneisel; Alex Gurevich

In this contribution, we present the results from a series of RF tests at 1.7 K and 2.0 K on a single-cell cavity made of high-purity large (with area of the order of few cm2) grain niobium which underwent various oxidation processes. After initial buffered chemical polishing, anodization, baking in pure oxygen atmosphere and baking in air up to 180 °C was applied with the objective of clearly identifying the role of oxygen and the oxide layer on the Q-drop. During each rf test a temperature mapping system was used allowing to measure the local temperature rise of the cavitymore » outer surface due to RF losses, which gives information about the losses location, their field dependence and space distribution on the RF surface. The results confirmed that the depth affected by baking is about 20 – 30 nm from the surface and showed that the Q-drop did not re-appear in a previously baked cavity by further baking at 120 °C in pure oxygen atmosphere or in air up to 180 °C. A statistic of the position of the “hot-spots” on the cavity surface showed that grain-boundaries are not the preferred location. An interesting correlation was found between the Q-drop onset, the quench field and the low-field energy gap, which supports the hypothesis of thermo-magnetic instability governing the Q-drop and the baking effect.« less

MEASUREMENT OF THE HIGH-FIELD Q-DROP IN A LARGE-GRAIN NIOBIUM CAVITY FOR DIFFERENT OXIDATION PROCESSES

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

Ciovati, Gianluigi; Kneisel, Peter; Gurevich, Alex

In this contribution, we present the results from a series of RF tests at 1.7 K and 2.0 K on a single-cell cavity made of high-purity large (with area of the order of few cm2) grain niobium which underwent various oxidation processes. After initial buffered chemical polishing, anodization, baking in pure oxygen atmosphere and baking in air up to 180 °C was applied with the objective of clearly identifying the role of oxygen and the oxide layer on the Q-drop. During each rf test a temperature mapping system was used allowing to measure the local temperature rise of the cavitymore » outer surface due to RF losses, which gives information about the losses location, their field dependence and space distribution on the RF surface. The results confirmed that the depth affected by baking is about 20 – 30 nm from the surface and showed that the Q-drop did not re-appear in a previously baked cavity by further baking at 120 °C in pure oxygen atmosphere or in air up to 180 °C. A statistic of the position of the "hot-spots" on the cavity surface showed that grain-boundaries are not the preferred location. An interesting correlation was found between the Q-drop onset, the quench field and the low-field energy gap, which supports the hypothesis of thermomagnetic instability governing the Q-drop and the baking effect.« less

Earthquake stress drop and laboratory-inferred interseismic strength recovery

USGS Publications Warehouse

Beeler, N.M.; Hickman, S.H.; Wong, T.-F.

2001-01-01

We determine the scaling relationships between earthquake stress drop and recurrence interval tr that are implied by laboratory-measured fault strength. We assume that repeating earthquakes can be simulated by stick-slip sliding using a spring and slider block model. Simulations with static/kinetic strength, time-dependent strength, and rate- and state-variable-dependent strength indicate that the relationship between loading velocity and recurrence interval can be adequately described by the power law VL ??? trn, where n=-1. Deviations from n=-1 arise from second order effects on strength, with n>-1 corresponding to apparent time-dependent strengthening and n<-1 corresponding to weakening. Simulations with rate and state-variable equations show that dynamic shear stress drop ????d scales with recurrence as d????d/dlntr ??? ??e(b-a), where ??e is the effective normal stress, ??=??/??e, and (a-b)=d??ss/dlnV is the steady-state slip rate dependence of strength. In addition, accounting for seismic energy radiation, we suggest that the static shear stress drop ????s scales as d????s/dlntr ??? ??e(1+??)(b-a), where ?? is the fractional overshoot. The variation of ????s with lntr for earthquake stress drops is somewhat larger than implied by room temperature laboratory values of ?? and b-a. However, the uncertainty associated with the seismic data is large and the discrepancy between the seismic observations and the rate of strengthening predicted by room temperature experiments is less than an order of magnitude. Copyright 2001 by the American Geophysical Union.

Experiments on Nitrogen Oxide Production of Droplet Arrays Burning under Microgravity Conditions

NASA Astrophysics Data System (ADS)

Moesl, Klaus; Sattelmayer, Thomas; Kikuchi, Masao; Yamamoto, Shin; Yoda, Shinichi

The optimization of the combustion process is top priority in current aero-engine and aircraft development, particularly from the perspectives of high efficiency, minimized fuel consumption, and a sustainable exhaust gas production. Aero-engines are exclusively liquid-fueled with a strong correlation between the combustion temperature and the emissions of nitric oxide (NOX ). Due to safety concerns, the progress in NOX reduction has been much slower than in stationary gas turbines. In the past, the mixing intensity in the primary zone of aero-engine combustors was improved and air staging implemented. An important question for future aero-engine combustors, consequently, is how partial vaporization influences the NOX emissions of spray flames? In order to address this question, the combustion of partially vaporized, linear droplet arrays was studied experimentally under microgravity conditions. The influence of fuel pre-vaporization on the NOX emissions was assessed in a wide range. The experiments were performed in a drop tower and a sounding rocket campaign. The microgravity environment provided ideal experiment conditions without the disturbing ef-fect of natural convection. This allowed the study of the interacting phenomena of multi-phase flow, thermodynamics, and chemical kinetics. This way the understanding of the physical and chemical processes related to droplet and spray combustion could be improved. The Bremen drop tower (ZARM) was utilized for the precursor campaign in July 2008, which was com-prised of 30 drops. The sounding rocket experiments, which totaled a microgravity duration of 6 minutes, were finally performed on the flight of TEXUS-46 in November 2009. On both campaigns the "Japanese Combustion Module" (JCM) was used. It is a cooperative experi-ment on droplet array combustion between the Japan Aerospace Exploration Agency (JAXA) and ESA's (European Space Agency) research team, working on the combustion properties of partially premixed sprays. One droplet array consisted of five droplets (for sounding rocket) and 9 -17 droplets (for drop tower) of the hydrocarbon n-decane (C10 H22 ). While keeping the pressure at 1.0 bar (+/-20 mbar), the combustion chamber temperature and the fuel vaporization time were varied in the range of 300 -500 K and 0.5 -18 s, respectively. Consequently, the total amount of fuel, the local equivalence ratio Φ along the droplet array, and the dimensionless droplet spacing S/d0 , with d0 being the initial droplet diameter, were adapted. Ignition was initiated by a hot-wire igniter from one end of the droplet array. Representative gas samples were collected from every single combustion sequence after flame extinction and stored in specially treated gas sampling cylinders for their succeeding analysis on ground. Visual observation of the combustion process, as well as temperature and pressure logging, supported the scientific interpretation of the gas analysis. With an increase of the preheating temperature, NOX emissions increase due to a higher effec-tive flame temperatures. However, with an increasing pre-vaporization, NOX emissions become lower due to the dropping number and the dropping size of burning droplets, acting as hot spots. A correction for the effect of the preheating temperature was developed. It reveals the effect of pre-vaporization and shows that the NOX emissions are almost independent of it for near-stoichiometric operation. At overall lean conditions the NOX emissions drop non-linearly with the degree of vaporization. Up to now, this leads to the conclusion that a high degree of vaporization is required in order to achieve substantial NOX abatement.

Spontaneous jumping, bouncing and trampolining of hydrogel drops on a heated plate.

PubMed

Pham, Jonathan T; Paven, Maxime; Wooh, Sanghyuk; Kajiya, Tadashi; Butt, Hans-Jürgen; Vollmer, Doris

2017-10-13

The contact between liquid drops and hot solid surfaces is of practical importance for industrial processes, such as thermal spraying and spray cooling. The contact and bouncing of solid spheres is also an important event encountered in ball milling, powder processing, and everyday activities, such as ball sports. Using high speed video microscopy, we demonstrate that hydrogel drops, initially at rest on a surface, spontaneously jump upon rapid heating and continue to bounce with increasing amplitudes. Jumping is governed by the surface wettability, surface temperature, hydrogel elasticity, and adhesion. A combination of low-adhesion impact behavior and fast water vapor formation supports continuous bouncing and trampolining. Our results illustrate how the interplay between solid and liquid characteristics of hydrogels results in intriguing dynamics, as reflected by spontaneous jumping, bouncing, trampolining, and extremely short contact times.Drops of liquid on a hot surface can exhibit fascinating behaviour such as the Leidenfrost effect in which drops hover on a vapour layer. Here Pham et al. show that when hydrogel drops are placed on a rapidly heated plate they bounce to increasing heights even if they were initially at rest.

Altering Genomic Integrity: Heavy Metal Exposure Promotes Transposable Element-Mediated Damage.

PubMed

Morales, Maria E; Servant, Geraldine; Ade, Catherine; Roy-Engel, Astrid M

2015-07-01

Maintenance of genomic integrity is critical for cellular homeostasis and survival. The active transposable elements (TEs) composed primarily of three mobile element lineages LINE-1, Alu, and SVA comprise approximately 30% of the mass of the human genome. For the past 2 decades, studies have shown that TEs significantly contribute to genetic instability and that TE-caused damages are associated with genetic diseases and cancer. Different environmental exposures, including several heavy metals, influence how TEs interact with its host genome increasing their negative impact. This mini-review provides some basic knowledge on TEs, their contribution to disease, and an overview of the current knowledge on how heavy metals influence TE-mediated damage.

Measurement of the high-field Q-drop in a high-purity large-grain niobium cavity for different oxidation processes

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

Ciovati, Gianluigi; Kneisel, Peter; gurevich, alex

The most challenging issue for understanding the performance of superconducting radio-frequency (rf) cavities made of high-purity (residual resistivity ratio > 200) niobium is due to a sharp degradation (“Q-drop”) of the cavity quality factor Q0(Bp) as the peak surface magnetic field (Bp) exceeds about 90 mT, in the absence of field emission. In addition, a low-temperature (100 – 140 C) “in-situ” baking of the cavity was found to be beneficial in reducing the Q-drop. In this contribution, we present the results from a series of rf tests at 1.7 K and 2.0 K on a single-cell cavity made of high-puritymore » large (with area of the order of few cm2) grain niobium which underwent various oxidation processes, after initial buffered chemical polishing, such as anodization, baking in pure oxygen atmosphere and baking in air up to 180 °C, with the objective of clearly identifying the role of oxygen and the oxide layer on the Q-drop. During each rf test a temperature mapping system allows measuring the local temperature rise of the cavity outer surface due to rf losses, which gives information about the losses location, their field dependence and space distribution. The results confirmed that the depth affected by baking is about 20 – 30 nm from the surface and showed that the Q-drop did not re-appear in a previously baked cavity by further baking at 120 °C in pure oxygen atmosphere or in air up to 180 °C. These treatments increased the oxide thickness and oxygen concentration, measured on niobium samples which were processed with the cavity and were analyzed with Transmission Electron Microscope (TEM) and Secondary Ion Mass Spectroscopy (SIMS). Nevertheless, the performance of the cavity after air baking at 180 °C degraded significantly and the temperature maps showed high losses, uniformly distributed on the surface, which could be completely recovered only by a post-purification treatment at 1250 °C. A statistic of the position of the “hot-spots” on the cavity surface showed that grain-boundaries are not the preferred location. An interesting correlation was found between the Q-drop onset, the quench field and the low-field energy gap, which supports the hypothesis of thermo-magnetic instability governing the Q-drop and the baking effect.« less

Coumarins as turn on/off fluorescent probes for detection of residual acetone in cosmetics following headspace single-drop microextraction.

PubMed

Cabaleiro, N; de la Calle, I; Bendicho, C; Lavilla, I

2014-11-01

In this work, a new method based on headspace-single drop microextraction for the determination of residual acetone in cosmetics by microfluorospectrometry is proposed. Acetone causes fluorescence changes in a 2.5 µL-ethanolic drop (40% v/v) containing 3.10(-4) mol L(-1) 7-hydroxy-4-methylcoumarin ('turn off') or 6.10(-6) mol L(-1) 7-diethylamino-4-methylcoumarin ('turn on'). Polarity and ability to form hydrogen bonds of short chain alcohols (polar protic solvents) were crucial in order to observe these changes in the presence of acetone (polar aprotic solvent). Parameters related with the HS-SDME procedure were studied, namely headspace volume, composition, volume and temperature of drop, microextraction time, stirring rate, mass and temperature of sample, as well as the effect of potential interferents (alcohols and fragrances). The high volatility of acetone allows its extraction from an untreated cosmetic sample within 3 min. A detection limit of 0.26 µg g(-1) and repeatability, expressed as relative standard deviation, around 5% were reached. Accuracy of the proposed methodology was evaluated by means of recovery studies. The method was successfully used to analyze different cosmetics. Simplicity and high sample throughput can be highlighted. Copyright © 2014 Elsevier B.V. All rights reserved.

From drop impact physics to spray cooling models: a critical review

NASA Astrophysics Data System (ADS)

Breitenbach, Jan; Roisman, Ilia V.; Tropea, Cameron

2018-03-01

Spray-wall interaction is an important process encountered in a large number of existing and emerging technologies and is the underlying phenomenon associated with spray cooling. Spray cooling is a very efficient technology, surpassing all other conventional cooling methods, especially those not involving phase change and not exploiting the latent heat of vaporization. However, the effectiveness of spray cooling is dependent on a large number of parameters, including spray characteristics like drop size, velocity and number density, the surface morphology, but also on the temperature range and thermal properties of the materials involved. Indeed, the temperature of the substrate can have significant influence on the hydrodynamics of drop and spray impact, an aspect which is seldom considered in model formulation. This process is extremely complex, thus most design rules to date are highly empirical in nature. On the other hand, significant theoretical progress has been made in recent years about the interaction of single drops with heated walls and improvements to the fundamentals of spray cooling can now be anticipated. The present review has the objective of summarizing some of these recent advances and to establish a framework for future development of more reliable and universal physics-based correlations to describe quantities involved in spray cooling.

Faraday forcing of high-temperature levitated liquid metal drops for the measurement of surface tension.

PubMed

Brosius, Nevin; Ward, Kevin; Matsumoto, Satoshi; SanSoucie, Michael; Narayanan, Ranga

2018-01-01

In this work, a method for the measurement of surface tension using continuous periodic forcing is presented. To reduce gravitational effects, samples are electrostatically levitated prior to forcing. The method, called Faraday forcing, is particularly well suited for fluids that require high temperature measurements such as liquid metals where conventional surface tension measurement methods are not possible. It offers distinct advantages over the conventional pulse-decay analysis method when the sample viscosity is high or the levitation feedback control system is noisy. In the current method, levitated drops are continuously translated about a mean position at a small, constant forcing amplitude over a range of frequencies. At a particular frequency in this range, the drop suddenly enters a state of resonance, which is confirmed by large executions of prolate/oblate deformations about the mean spherical shape. The arrival at this resonant condition is a signature that the parametric forcing frequency is equal to the drop's natural frequency, the latter being a known function of surface tension. A description of the experimental procedure is presented. A proof of concept is given using pure Zr and a Ti 39.5 Zr 39.5 Ni 21 alloy as examples. The results compare favorably with accepted literature values obtained using the pulse-decay method.

The measured temperature and pressure of EDC37 detonation products

NASA Astrophysics Data System (ADS)

Ferguson, J. W.; Richley, J. C.; Sutton, B. D.; Price, E.; Ota, T. A.

2017-01-01

We present the experimentally determined temperature and pressure of the detonation products of EDC37; a HMX based conventional high explosive. These measurements were performed on a series of cylinder tests. The temperature measurements were undertaken at the end of the cylinder with optical fibres observing the bare explosive through a LiF window. The temperature of the products was measured for approximately 2 µs using single colour pyrometry, multicolour pyrometry and also using time integrated optical emission spectroscopy with the results from all three methods being broadly consistent. The peak temperature was found to be ≈ 3600 K dropping to ≈ 2400 K at the end of the measurement window. The spectroscopy was time integrated and showed that the emission spectra can be approximated using a grey body curve between 520 - 800 nm with no emission or absorption lines being observed. The pressure was obtained using an analytical method which requires the velocity of the expanding cylinder wall and the velocity of detonation. The pressure drops from an initial CJ value of ≈ 38 GPa to ≈ 4 GPa after 2 µs.

Introduction.

ERIC Educational Resources Information Center

Voneche, Jacques

1984-01-01

Discusses ontogeny and phylogeny in Piaget's work, differences between Piagetian (constructivist) and Darwinian (selectionist) approaches, and problems associated with transposing conceptual systems from one field to another. (RH)

Current and temperature distributions in-situ acquired by electrode-segmentation along a microtubular solid oxide fuel cell operating with syngas

NASA Astrophysics Data System (ADS)

Aydın, Özgür; Nakajima, Hironori; Kitahara, Tatsumi

2015-10-01

Addressing the fuel distribution and endothermic cooling by the internal reforming, we have measured longitudinal current/temperature variations by ;Electrode-segmentation; in a microtubular solid oxide fuel cell operated with syngas (50% pre-reformed methane) and equivalent H2/N2 (100% conversion of syngas to H2) at three different flow rates. Regardless of the syngas flow rates, currents and temperatures show irregular fluctuations with varying amplitudes from upstream to downstream segment. Analysis of the fluctuations suggests that the methane steam reforming reaction is highly affected by the H2 partial pressure. Current-voltage curves plotted for the syngas and equivalent H2/N2 flow rates reveal that the fuel depletion is enhanced toward the downstream during the syngas operation, resulting in a larger performance degradation. All the segments exhibit temperature drops with the syngas flow compared with the equivalent H2/N2 flow due to the endothermic cooling by the methane steam reforming reaction. Despite the drops, the segment temperatures remain above the furnace temperature; besides, the maximum temperature difference along the cell diminishes. The MSR reaction rate does not consistently increase with the decreasing gas inlet velocity (increasing residence time on the catalyst); which we ascribe to the dominating impact of the local temperatures.

Heat transfer and pressure drop for air flow through enhanced passages

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

Obot, N.T.; Esen, E.B.

1992-06-01

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effectmore » depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.« less

Heat transfer and pressure drop for air flow through enhanced passages. Final report

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

Obot, N.T.; Esen, E.B.

1992-06-01

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effectmore » depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.« less

Transposable element evolution in Heliconius suggests genome diversity within Lepidoptera

PubMed Central

2013-01-01

Background Transposable elements (TEs) have the potential to impact genome structure, function and evolution in profound ways. In order to understand the contribution of transposable elements (TEs) to Heliconius melpomene, we queried the H. melpomene draft sequence to identify repetitive sequences. Results We determined that TEs comprise ~25% of the genome. The predominant class of TEs (~12% of the genome) was the non-long terminal repeat (non-LTR) retrotransposons, including a novel SINE family. However, this was only slightly higher than content derived from DNA transposons, which are diverse, with several families having mobilized in the recent past. Compared to the only other well-studied lepidopteran genome, Bombyx mori, H. melpomene exhibits a higher DNA transposon content and a distinct repertoire of retrotransposons. We also found that H. melpomene exhibits a high rate of TE turnover with few older elements accumulating in the genome. Conclusions Our analysis represents the first complete, de novo characterization of TE content in a butterfly genome and suggests that, while TEs are able to invade and multiply, TEs have an overall deleterious effect and/or that maintaining a small genome is advantageous. Our results also hint that analysis of additional lepidopteran genomes will reveal substantial TE diversity within the group. PMID:24088337

On the nature of consonant/vowel differences in letter position coding: Evidence from developing and adult readers.

PubMed

Comesaña, Montserrat; Soares, Ana P; Marcet, Ana; Perea, Manuel

2016-11-01

In skilled adult readers, transposed-letter effects (jugde-JUDGE) are greater for consonant than for vowel transpositions. These differences are often attributed to phonological rather than orthographic processing. To examine this issue, we employed a scenario in which phonological involvement varies as a function of reading experience: A masked priming lexical decision task with 50-ms primes in adult and developing readers. Indeed, masked phonological priming at this prime duration has been consistently reported in adults, but not in developing readers (Davis, Castles, & Iakovidis, 1998). Thus, if consonant/vowel asymmetries in letter position coding with adults are due to phonological influences, transposed-letter priming should occur for both consonant and vowel transpositions in developing readers. Results with adults (Experiment 1) replicated the usual consonant/vowel asymmetry in transposed-letter priming. In contrast, no signs of an asymmetry were found with developing readers (Experiments 2-3). However, Experiments 1-3 did not directly test the existence of phonological involvement. To study this question, Experiment 4 manipulated the phonological prime-target relationship in developing readers. As expected, we found no signs of masked phonological priming. Thus, the present data favour an interpretation of the consonant/vowel dissociation in letter position coding as due to phonological rather than orthographic processing. © 2016 The British Psychological Society.

Pictorial relief for equiluminant images

NASA Astrophysics Data System (ADS)

van Doorn, Andrea J.; de Ridder, Huib; Koenderink, Jan J.

2005-03-01

Pictorial relief depends strongly on "cues" in the image. For isoluminant renderings some cues are missing, namely all information that is related to luminance contrast (e.g., shading, atmospheric perspective). It has been suggested that spatial discrimination and especially pictorial space suffer badly in isoluminant conditions. We have investigated the issue through quantitative measurement of pictorial depth-structure under normal and isoluminant conditions. As stimuli we used monochrome halftone photographs, either as such, or "transposed" to Red/Green or Green/Red hue modulations. We used two distinct methods, one to probe pictorial pose (by way of correspondences settings between pictures of an object in different poses), the other to probe pictorial depth (by way of attitude settings of a gauge figure to a perceptual "fit"). In both experiments the depth reconstructions for Red/Green, Green/Red and monochrome conditions were very similar. Moreover, observers performed equally well in Red/Green, Green/Red and monochrome conditions. Thus, the general conclusion is that observers did not do markedly worse with the isoluminant Red/Green and Green/Red transposed images. Whereas the transposed images certainly looked weird, they were easily interpreted. Much of the structure of pictorial space was apparently preserved. Thus the notion that spatial representations are not sustained under isoluminant conditions should be applied with caution.

Distribution of Unlinked Transpositions of a Ds Element from a T-DNA Locus on Tomato Chromosome 4

PubMed Central

Briza, J.; Carroll, B. J.; Klimyuk, V. I.; Thomas, C. M.; Jones, D. A.; Jones, JDG.

1995-01-01

In maize, receptor sites for unlinked transpositions of Activator (Ac) elements are not distributed randomly. To test whether the same is true in tomato, the receptor sites for a Dissociation (Ds) element derived from Ac, were mapped for 26 transpositions unlinked to a donor T-DNA locus on chromosome 4. Four independent transposed Dss mapped to sites on chromosome 4 genetically unlinked to the donor T-DNA, consistent with a preference for transposition to unlinked sites on the same chromosome as opposed to sites on other chromosomes. There was little preference among the nondonor chromosomes, except perhaps for chromosome 2, which carried seven transposed Dss, but these could not be proven to be independent. However, these data, when combined with those from other studies in tomato examining the distribution of transposed Acs or Dss among nondonor chromosomes, suggest there may be absolute preferences for transposition irrespective of the chromosomal location of the donor site. If true, transposition to nondonor chromosomes in tomato would differ from that in maize, where the preference seems to be determined by the spatial arrangement of chromosomes in the interphase nucleus. The tomato lines carrying Ds elements at known locations are available for targeted transposon tagging experiments. PMID:8536985

From Embryo to Adult: piRNA-Mediated Silencing throughout Germline Development in Drosophila

PubMed Central

Marie, Pauline P.; Ronsseray, Stéphane; Boivin, Antoine

2016-01-01

In metazoan germ cells, transposable element activity is repressed by small noncoding PIWI-associated RNAs (piRNAs). Numerous studies in Drosophila have elucidated the mechanism of this repression in the adult germline. However, when and how transposable element repression is established during germline development has not been addressed. Here, we show that homology-dependent trans silencing is active in female primordial germ cells from late embryogenesis through pupal stages, and that genes related to the adult piRNA pathway are required for silencing during development. In larval gonads, we detect rhino-dependent piRNAs indicating de novo biogenesis of functional piRNAs during development. Those piRNAs exhibit the molecular signature of the “ping-pong” amplification step. Moreover, we show that Heterochromatin Protein 1a is required for the production of piRNAs coming from telomeric transposable elements. Furthermore, as in adult ovaries, incomplete, bimodal, and stochastic repression resembling variegation can occur at all developmental stages. Clonal analysis indicates that the repression status established in embryonic germ cells is maintained until the adult stage, suggesting the implication of a cellular memory mechanism. Taken together, data presented here show that piRNAs and their associated proteins are epigenetic components of a continuous repression system throughout germ cell development. PMID:27932388

Thermostatic tissue platform for intravital microscopy: 'the hanging drop' model.

PubMed

Pavlovic, Dragan; Frieling, Helge; Lauer, Kai-Stephan; Bac, Vo Hoai; Richter, Joern; Wendt, Michael; Lehmann, Christian; Usichenko, Taras; Meissner, Konrad; Gruendling, Matthias

2006-11-01

Intravital microscopy imposes the particular problem of the combined control of the body temperature of the animal and the local temperature of the observed organ or tissues. We constructed and tested, in the rat ileum microcirculation preparation, a new organ-support platform. The platform consisted of an organ bath filled with physiological solution, and contained a suction tube, a superfusion tube, an intestine-support hand that was attached to a micromanipulator and a thermometer probe. To cover the intestine we used a cover glass plate with a plastic ring glued on its upper surface. After a routine procedure (anaesthesia, monitoring and surgery), the intestine segment (2-3 cm long) was gently exteriorized and placed on the 'hand' of the organ support. A small part of the intestine formed a small 'island' in the bath that was filled with physiological salt solution. The cover glass was secured in place. The physiological salt solution from the superfusion tube, which was pointed to the lower surface of the cover glass, formed a 'hanging drop'. The objective of the microscope was then immersed into distilled water that was formed by the cover glass plastic ring. The 'hanging drop' technique prevented any tissue quenching, ensured undisturbed microcirculation, provided for stable temperature and humidity, and permitted a clear visual field.

Pressure driven flow of superfluid 4He through a nanopipe

NASA Astrophysics Data System (ADS)

Botimer, Jeffrey; Taborek, Peter

2016-09-01

Pressure driven flow of superfluid helium through single high-aspect-ratio glass nanopipes into a vacuum has been studied for a wide range of pressure drop (0-30 bars), reservoir temperature (0.8-2.5 K), pipe lengths (1-30 mm), and pipe radii (131 and 230 nm). As a function of pressure drop we observe two distinct flow regimes above and below a critical pressure drop Pc. For P

Computer program MCAP-TOSS calculates steady-state fluid dynamics of coolant in parallel channels and temperature distribution in surrounding heat-generating solid

NASA Technical Reports Server (NTRS)

Lee, A. Y.

1967-01-01

Computer program calculates the steady state fluid distribution, temperature rise, and pressure drop of a coolant, the material temperature distribution of a heat generating solid, and the heat flux distributions at the fluid-solid interfaces. It performs the necessary iterations automatically within the computer, in one machine run.

75 FR 68719 - Endangered and Threatened Wildlife and Plants; Emergency Rule To Establish a Manatee Refuge in...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-09

... Mexico water temperatures drop to about 68 [deg]F (20 [deg]C), manatees looking for warmer water will... shelter, rest, and feed free from harassment, manatees are at risk when exposed to cold temperatures for... harassment due to the cold temperatures that confine them to Kings Bay. Designating manatee protection areas...

Method of measuring thermal conductivity of high performance insulation

NASA Technical Reports Server (NTRS)

Hyde, E. H.; Russell, L. D.

1968-01-01

Method accurately measures the thermal conductivity of high-performance sheet insulation as a discrete function of temperature. It permits measurements to be made at temperature drops of approximately 10 degrees F across the insulation and ensures measurement accuracy by minimizing longitudinal heat losses in the system.

Paracetamol suppositories: a comparative study.

PubMed Central

Cullen, S; Kenny, D; Ward, O C; Sabra, K

1989-01-01

Paracetamol suppositories in two different bases were given to children who had fever after operations. Plasma concentrations and the effect on temperature were compared. There was a significant correlation between peak plasma concentrations and maximum drop in temperature. A lipophilic base produced better results than a hydrophilic base. PMID:2817936

Mechanical and Infrared Thermography Analysis of Shape Memory Polyurethane

NASA Astrophysics Data System (ADS)

Pieczyska, Elzbieta Alicja; Maj, Michal; Kowalczyk-Gajewska, Katarzyna; Staszczak, Maria; Urbanski, Leszek; Tobushi, Hisaaki; Hayashi, Shunichi; Cristea, Mariana

2014-07-01

Multifunctional new material—polyurethane shape memory polymer (PU-SMP)—was subjected to tension carried out at room temperature at various strain rates. The influence of effects of thermomechanical couplings on the SMP mechanical properties was studied, based on the sample temperature changes, measured by a fast and sensitive infrared camera. It was found that the polymer deformation process strongly depends on the strain rate applied. The initial reversible strain is accompanied by a small drop in temperature, called thermoelastic effect. Its maximal value is related to the SMP yield point and increases upon increase of the strain rate. At higher strains, the stress and temperature significantly increase, caused by reorientation of the polymer molecular chains, followed by the stress drop and its subsequent increase accompanying the sample rupture. The higher strain rate, the higher stress, and temperature changes were obtained, since the deformation process was more dynamic and has occurred in almost adiabatic conditions. The constitutive model of SMP valid in finite strain regime was developed. In the proposed approach, SMP is described as a two-phase material composed of hyperelastic rubbery phase and elastic-viscoplastic glassy phase, while the volume content of phases is specified by the current temperature.

Genomic patterns associated with paternal/maternal distribution of transposable elements

NASA Astrophysics Data System (ADS)

Jurka, Jerzy

2003-03-01

Transposable elements (TEs) are specialized DNA or RNA fragments capable of surviving in intragenomic niches. They are commonly, perhaps unjustifiably referred to as "selfish" or "parasitic" elements. TEs can be divided in two major classes: retroelements and DNA transposons. The former include non-LTR retrotransposons and retrovirus-like elements, using reverse transriptase for their reproduction prior to integration into host DNA. The latter depend mostly on host DNA replication, with possible exception of rolling-circle transposons recently discovered by our team. I will review basic information on TEs, with emphasis on human Alu and L1 retroelements discussed in the context of genomic organization. TEs are non-randomly distributed in chromosomal DNA. In particular, human Alu elements tend to prefer GC-rich regions, whereas L1 accumulate in AT-rich regions. Current explanations of this phenomenon focus on the so called "target effects" and post-insertional selection. However, the proposed models appear to be unsatisfactory and alternative explanations invoking "channeling" to different chromosomal regions will be a major focus of my presentation. Transposable elements (TEs) can be expressed and integrated into host DNA in the male or female germlines, or both. Different models of expression and integration imply different proportions of TEs on sex chromosomes and autosomes. The density of recently retroposed human Alu elements is around three times higher on chromosome Y than on chromosome X, and over two times higher than the average density for all human autosomes. This implies Alu activity in paternal germlines. Analogous inter-chromosomal proportions for other repeat families should determine their compatibility with one of the three basic models describing the inheritance of TEs. Published evidence indicates that maternally and paternally imprinted genes roughly correspond to GC-rich and AT-rich DNA. This may explain the observed chromosomal distribution of Alu and L1 elements. Finally, paternal models of inheritance predict rapid accumulation of active TEs on chromosome Y. I will discuss potential implications of this phenomenon for evolution of chromosome Y and transposable elements.

Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry and tandem mass spectrometry for peptide de novo amino acid sequencing for a seven-protein mixture by paired single-residue transposed Lys-N and Lys-C digestion.

PubMed

Guan, Xiaoyan; Brownstein, Naomi C; Young, Nicolas L; Marshall, Alan G

2017-01-30

Bottom-up tandem mass spectrometry (MS/MS) is regularly used in proteomics to identify proteins from a sequence database. De novo sequencing is also available for sequencing peptides with relatively short sequence lengths. We recently showed that paired Lys-C and Lys-N proteases produce peptides of identical mass and similar retention time, but different tandem mass spectra. Such parallel experiments provide complementary information, and allow for up to 100% MS/MS sequence coverage. Here, we report digestion by paired Lys-C and Lys-N proteases of a seven-protein mixture: human hemoglobin alpha, bovine carbonic anhydrase 2, horse skeletal muscle myoglobin, hen egg white lysozyme, bovine pancreatic ribonuclease, bovine rhodanese, and bovine serum albumin, followed by reversed-phase nanoflow liquid chromatography, collision-induced dissociation, and 14.5 T Fourier transform ion cyclotron resonance mass spectrometry. Matched pairs of product peptide ions of equal precursor mass and similar retention times from each digestion are compared, leveraging single-residue transposed information with independent interferences to confidently identify fragment ion types, residues, and peptides. Selected pairs of product ion mass spectra for de novo sequenced protein segments from each member of the mixture are presented. Pairs of the transposed product ions as well as complementary information from the parallel experiments allow for both high MS/MS coverage for long peptide sequences and high confidence in the amino acid identification. Moreover, the parallel experiments in the de novo sequencing reduce false-positive matches of product ions from the single-residue transposed peptides from the same segment, and thereby further improve the confidence in protein identification. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Proteomic analysis of urine in patients with intestinal segments transposed into the urinary tract.

PubMed

Nabi, Ghulam; N'Dow, James; Hasan, Tahseen S; Booth, Ian R; Cash, Phil

2005-04-01

Intestinal segments are used to replace or reconstruct the urinary bladder when it has become dysfunctional or develops life-threatening disease such as cancer. The quality of life in patients with intestinal segments used to either enlarge or completely replace the native bladder is adversely affected by recurrent urinary tract infections, excessive mucus production and the occasional development of malignancy. At present, there is no reliable method of predicting or noninvasively monitoring these patients for the development of these complications. The characterisation of proteins secreted into urine from the transposed intestinal segments could serve as important indicators of these clinical complications. Urine is an ideal source of material in which to search for biomarkers, since it bathes the affected tissues and can be obtained relatively easily by noninvasive methods. The urinary proteome of patients with intestinal segments transposed into the urinary tract is unknown and we present the first global description of the urinary protein profile in these patients. Sample preparation is a critical step in achieving accurate and reliable data. We describe a method to prepare urinary proteins that was compatible with their subsequent analysis using two-dimensional polyacrylamide gel electrophoresis. This method helped to overcome some of the technical problems encountered in analysing urine from this patient cohort. The method was used to analyse urinary proteins recovered from five healthy controls and ten patients with intestinal segments transposed into the urinary tract. Four low molecular weight proteins were found to be present in nine out of ten for the patient group but for none of the healthy controls. The four proteins were identified as lithostathine-1 alpha precursor, pancreatitis associated protein-1 precursor, liver fatty acid binding protein and testis expressed protein-12. The role of these proteins as potential biomarkers of intestinal cell activity within the reconstructed bladder is discussed.

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

Kerr, R.A.

As scientists and politicians anxiously eye signs of global greenhouse warming, climatologists are finding the best evidence yet that a massive volcanic eruption can temporarily bring the temperature down a notch or two. Such a cooling could be enough to set the current global warming back more than a decade, confusing any efforts to link it to the greenhouse effect. By effectively eliminating some nonvolcanic climate changes from the record of the past 100 years, researchers have detected drops in global temperature of several tenths of a degree within 1 to 2 years of volcanic eruptions. Apparently, the debris spewedmore » into the stratosphere blocked sunlight and caused the temperature drops. For all their potential social significance, the climate effects of volcanoes have been hard to detect. The problem has been in identifying a volcanic cooling among the nearly continuous climate warmings and coolings of a similar size that fill the record. The paper reviews how this was done.« less

Nonthermal ice nucleation observed at distorted contact lines of supercooled water drops

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

Yang, Fan; Cruikshank, Owen; He, Weilue

Ice nucleation is the crucial step for ice formation in atmospheric clouds and therefore underlies climatologically relevant precipitation and radiative properties. Some progress has been made in understanding the roles of temperature, supersaturation, and material properties, but an explanation for the efficient ice nucleation occurring when a particle contacts a supercooled water drop has been elusive for over half a century. Here, we explore ice nucleation initiated at constant temperature and observe that mechanical agitation induces freezing of supercooled water drops at distorted contact lines. Results show that symmetric motion of supercooled water on a vertically oscillating substrate does notmore » freeze, no matter how we agitate it. However, when the moving contact line is distorted with the help of trace amounts of oil or inhomogeneous pinning on the substrate, freezing can occur at temperatures much higher than in a static droplet, equivalent to ~1010 increase in nucleation rate. Several possible mechanisms are proposed to explain the observations. One plausible explanation among them, decreased pressure due to interface curvature, is explored theoretically and compared with the observational results quasiquantitatively. Indeed, the observed freezing-temperature increase scales with contact line speed in a manner consistent with the pressure hypothesis. Whatever the mechanism, the experiments demonstrate a strong preference for ice nucleation at three-phase contact lines compared to the two-phase interface, and they also show that movement and distortion of the contact line are necessary contributions to stimulating the nucleation process.« less

Nonthermal ice nucleation observed at distorted contact lines of supercooled water drops

DOE PAGES

Yang, Fan; Cruikshank, Owen; He, Weilue; ...

2018-02-06

Ice nucleation is the crucial step for ice formation in atmospheric clouds and therefore underlies climatologically relevant precipitation and radiative properties. Some progress has been made in understanding the roles of temperature, supersaturation, and material properties, but an explanation for the efficient ice nucleation occurring when a particle contacts a supercooled water drop has been elusive for over half a century. Here, we explore ice nucleation initiated at constant temperature and observe that mechanical agitation induces freezing of supercooled water drops at distorted contact lines. Results show that symmetric motion of supercooled water on a vertically oscillating substrate does notmore » freeze, no matter how we agitate it. However, when the moving contact line is distorted with the help of trace amounts of oil or inhomogeneous pinning on the substrate, freezing can occur at temperatures much higher than in a static droplet, equivalent to ~1010 increase in nucleation rate. Several possible mechanisms are proposed to explain the observations. One plausible explanation among them, decreased pressure due to interface curvature, is explored theoretically and compared with the observational results quasiquantitatively. Indeed, the observed freezing-temperature increase scales with contact line speed in a manner consistent with the pressure hypothesis. Whatever the mechanism, the experiments demonstrate a strong preference for ice nucleation at three-phase contact lines compared to the two-phase interface, and they also show that movement and distortion of the contact line are necessary contributions to stimulating the nucleation process.« less

Nonthermal ice nucleation observed at distorted contact lines of supercooled water drops

NASA Astrophysics Data System (ADS)

Yang, Fan; Cruikshank, Owen; He, Weilue; Kostinski, Alex; Shaw, Raymond A.

2018-02-01

Ice nucleation is the crucial step for ice formation in atmospheric clouds and therefore underlies climatologically relevant precipitation and radiative properties. Progress has been made in understanding the roles of temperature, supersaturation, and material properties, but an explanation for the efficient ice nucleation occurring when a particle contacts a supercooled water drop has been elusive for over half a century. Here, we explore ice nucleation initiated at constant temperature and observe that mechanical agitation induces freezing of supercooled water drops at distorted contact lines. Results show that symmetric motion of supercooled water on a vertically oscillating substrate does not freeze, no matter how we agitate it. However, when the moving contact line is distorted with the help of trace amounts of oil or inhomogeneous pinning on the substrate, freezing can occur at temperatures much higher than in a static droplet, equivalent to ˜1010 increase in nucleation rate. Several possible mechanisms are proposed to explain the observations. One plausible explanation among them, decreased pressure due to interface curvature, is explored theoretically and compared with the observational results quasiquantitatively. Indeed, the observed freezing-temperature increase scales with contact line speed in a manner consistent with the pressure hypothesis. Whatever the mechanism, the experiments demonstrate a strong preference for ice nucleation at three-phase contact lines compared to the two-phase interface, and they also show that movement and distortion of the contact line are necessary contributions to stimulating the nucleation process.

Nonthermal ice nucleation observed at distorted contact lines of supercooled water drops.

PubMed

Yang, Fan; Cruikshank, Owen; He, Weilue; Kostinski, Alex; Shaw, Raymond A

2018-02-01

Ice nucleation is the crucial step for ice formation in atmospheric clouds and therefore underlies climatologically relevant precipitation and radiative properties. Progress has been made in understanding the roles of temperature, supersaturation, and material properties, but an explanation for the efficient ice nucleation occurring when a particle contacts a supercooled water drop has been elusive for over half a century. Here, we explore ice nucleation initiated at constant temperature and observe that mechanical agitation induces freezing of supercooled water drops at distorted contact lines. Results show that symmetric motion of supercooled water on a vertically oscillating substrate does not freeze, no matter how we agitate it. However, when the moving contact line is distorted with the help of trace amounts of oil or inhomogeneous pinning on the substrate, freezing can occur at temperatures much higher than in a static droplet, equivalent to ∼10^{10} increase in nucleation rate. Several possible mechanisms are proposed to explain the observations. One plausible explanation among them, decreased pressure due to interface curvature, is explored theoretically and compared with the observational results quasiquantitatively. Indeed, the observed freezing-temperature increase scales with contact line speed in a manner consistent with the pressure hypothesis. Whatever the mechanism, the experiments demonstrate a strong preference for ice nucleation at three-phase contact lines compared to the two-phase interface, and they also show that movement and distortion of the contact line are necessary contributions to stimulating the nucleation process.

A Validated All-Pressure Fluid Drop Model and Lewis Number Effects for a Binary Mixture

NASA Technical Reports Server (NTRS)

Harstad, K.; Bellan, J.

1999-01-01

The differences between subcritical liquid drop and supercritical fluid drop behavior are discussed. Under subcritical, evaporative high emission rate conditions, a film layer is present in the inner part of the drop surface which contributes to the unique determination of the boundary conditions; it is this film layer which contributes to the solution's convective-diffusive character. In contrast, under supercritical condition as the boundary conditions contain a degree of arbitrariness due to the absence of a surface, and the solution has then a purely diffusive character. Results from simulations of a free fluid drop under no-gravity conditions are compared to microgravity experimental data from suspended, large drop experiments at high, low and intermediary temperatures and in a range of pressures encompassing the sub-and supercritical regime. Despite the difference between the conditions of the simulations and experiments (suspension vs. free floating), the time rate of variation of the drop diameter square is remarkably well predicted in the linear curve regime. The drop diameter is determined in the simulations from the location of the maximum density gradient, and agrees well with the data. It is also shown that the classical calculation of the Lewis number gives qualitatively erroneous results at supercritical conditions, but that an effective Lewis number previously defined gives qualitatively correct estimates of the length scales for heat and mass transfer at all pressures.

[Newly designed skin temperature monitoring system for microvascular anastomosis--an experimental and clinical study (author's transl)].

PubMed

Okutsu, I

1982-05-01

Blood circulation must be carefully evaluated following the microvascular anastomosis, such replantation of the digits and hands, free toe-to-hand transfer, and free flaps. From May 173, we have performed replantation of forty-five digits, seven wrists or forearm in thirty-four patients and one leg in one patient. The overall survival rate was 92.5%, including near total amputation. Also, from May 1974, we have performed eleven free flaps or free musculocutaneous flaps in ten patients. Seven out of eleven free flaps survived without any problems. The clinical inspections such as skin color and capillary refill are of subjective nature, and not always reliable. Therefore, from 1974, we have been measuring the skin temperature in the revascularized parts by means of a thermister. We usually use an electric blanket to warm the proximal part of the operated limb to maintain the peripheral circulation. Under normal ward environment, we analyzed the patterns of temperature fluctuations, and compared them against the revascularized parts and control sites. On our animal experiments, with the rats' hind limbs, a drastic temperature drop by about 2.0 degrees C was observed in 30 min, compared against the control group, when either artery or vein or both were obstructed. In the cases of the replantations, the skin temperature of control digits ranged from 30.4 to 37.1 degrees C. It usually remained above 32.0 degrees, fluctuating within 3 degrees. Also the skin temperatures of the successfully replanted parts and free flaps usually indicated the level above 32.0 degrees C, which corresponds to more than 80% of the axillary temperature in replanted cases and 90% in free flaps. In one failure case of replantation, the skin temperature fluctuated fom 27.2 to 32.1 degrees. On the fifth post operative day, the temperature suddenly dropped by 5 degrees in two hours. Arteriography was performed, and the arterial obstruction was confirmed. For the four flap operations, the skin temperatures had dropped below 32.0 degrees C, of which two had recovered by an auto-vein graft and the removal of haematoma respectively. We have concluded from these results, that the critical skin temperature in replantation and free flap cases was apparently above 32.0 degrees C in the normal ward environment. Based on our experiences, we have designed a continuous skin temperature monitoring device which consists of a resistance bridge and a thermister. The power source is a D.C. 12V. A high accuracy is maintained at the range of 32.1 +/- 0.3 degrees C when the system is set at 32.0 degrees C in the ward. The circuit is designed to flash a blue lamp when the temperature of the operated site is maintained above the pre-established temperature, while a red lamp and buzz signal give a warning when the temperature drops below the pre-established temperature. This equipment and skin thermometer have been simultaneously used following the various operations of microvascular anastomoses...

Oceans Melting Greenland OMG 2017 Media Reel

NASA Image and Video Library

2017-12-05

The Oceans Melting Greenland mission seeks to understand how ocean water is contributing to ice loss in Greenland. In October 2017, mission scientists and crew dropped 240 ocean probes from a C-130 aircraft into the waters around Greenland to measure ocean temperature and salinity. Footage includes aerial shots of Greenland landscapes, interior and exterior shots of the aircraft with crew and scientists at work, and shots from a chase plane showing the probes dropping.

Effects of aeration on matrix temperature by infrared thermal imager and computational fluid dynamics during sludge bio-drying.

PubMed

Yu, Dawei; Yang, Min; Qi, Lu; Liu, Mengmeng; Wang, Yawei; Wei, Yuansong

2017-10-01

The effect of aeration on the pile matrix temperature was investigated using thermocouples and Infrared Thermal Imager (IRI) for temperature sensing, and Computational Fluid Dynamics (CFD) for modelling of temperature variation during aeration in a full-scale sludge biodrying plant. With aeration saving of 20%, the improved strategy speeded up biodrying from 21 days to 14 days, while achieving similar drying effect. A persistent thermocouple recorded the one-dimensional (1D) total temperature variation of all aeration strategies. The IRI captured the rapid two-dimensional (2D) pile temperature dropped from 72.5 °C to 30.3 °C during 6 min of aeration, which mechanism suggested as the latent heat of moisture evaporation and sensible heat of air exchange. The CFD three-dimensional (3D) CFD results highlight the importance of latent heat rather than sensible heat. Therefore, the pile temperature drop inferred is ΔT = 5.38 °C theoretically and ΔT = 5.17 ± 4.56 °C practically, per unit of MC removed. These findings also emphasize the possibility of a pile temperature valley, due to excessive aeration under unsaturated vapour conditions. Surface temperature monitored by IRI coupled with 3D temperature simulated by CFD rapidly gives a clear matrix temperature evolution, empowering biodrying by more accurate temperature and aeration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electron-Hole Condensation in Semiconductors: Electrons and holes condense into freely moving liquid metallic droplets, a plasma phase with novel properties.

PubMed

Jeffries, C D

1975-09-19

In Ge and Si, and also in Ge-Si alloys (74), there is extensive evidence for the stable binding of electrons and holes into a cold plasma of constant density, which undergoes a phase separation. Liquid metallic drops 1 to 300 microm in size are formed, with lifetimes ranging from 0.1 to 600 microsec. For Ge a surprising amount is known: the phase diagram, the surface energy, the work function, the decay kinetics. Much less is known for Si. There is good agreement between theoretical and experimental values of the liquid density, the critical density, the critical temperature, and the binding energy. The stability of the liquid phase is strikingly dependent on band structure. The multivalley structure and mass anisotropy of Si, Ge, and Ge-Si, together with their indirect band gap, are no doubt responsible for the observed stability in these crystals. In the similar semiconductor gallium phosphide, drops have not yet been observed, most likely because the high impurity content traps the excitons. In gallium arsenide the existence of drops is controversial (75). Undoubtedly drops will be found to exist in other semiconductors, perhaps at even higher temperatures. This is an exciting field for the experimentalist; new phenomena are being rapidly discovered, usually before they are predicted. For the theorist, the electron-hole drop is of high intrinsic interest. It represents the first example of a quantum liquid of constant density in a periodic crystal lattice. A number of challenging experimental and theoretical problems remain.

The Cooling of Turbine Blades,

DTIC Science & Technology

1981-06-11

aviation gas turbine engine , everyone has ceaselessly come up with ways of raising the temperature of gases in a turbine before combustion. The reason for...temperature of the blade concerned by approximately 200 degrees. Jet -type cooling. When the surface of a turbine blade is at a temperature which is...the blade and multiplying the drop in the temperature of the blade . Figure 3 is a cross-section diagram of a turbine blade cooled by the jet

46 CFR 54.05-5 - Toughness test specimens.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., transversely oriented specimens must be used. When longitudinal specimens are used, the required energy values...-Ductility Transition Temperature of Ferritic Steels”. For material thicknesses between 1/2-inch and 5/8-inch... correlate with the nil-ductility transition temperature determined by the drop-weight tests for the steels...

46 CFR 54.05-5 - Toughness test specimens.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., transversely oriented specimens must be used. When longitudinal specimens are used, the required energy values...-Ductility Transition Temperature of Ferritic Steels”. For material thicknesses between 1/2-inch and 5/8-inch... correlate with the nil-ductility transition temperature determined by the drop-weight tests for the steels...

Fiber optic photoelastic pressure sensor for high temperature gases

NASA Technical Reports Server (NTRS)

Wesson, Laurence N.; Redner, Alex S.; Baumbick, Robert J.

1990-01-01

A novel fiber optic pressure sensor based on the photoelastic effects has been developed for extremely high temperature gases. At temperatures varying from 25 to 650 C, the sensor experiences no change in the peak pressure of the transfer function and only a 10 percent drop in dynamic range. Refinement of the sensor has resulted in an optoelectronic interface and processor software which can calculate pressure values within 1 percent of full scale at any temperature within the full calibrated temperature range.

Experimental Analysis of Heat Transfer Characteristics and Pressure Drop through Screen Regenerative Heat Exchangers

DTIC Science & Technology

1993-12-01

of fluid T1 initial temperature of matrix and fluid Tf1 average inlet temperature after the step change Tii average inlet temperature before the step...respectively, of the regenerator. The horizontal distances shown with Tf1 , Tj, and T,2 illustrate the time interval for which the average values were...temperature was not a true step function, the investigator made an approximation. The approximation was based on an average temperature. Tf1 was the

Retrotransposons as regulators of gene expression

PubMed Central

Elbarbary, Reyad A.; Lucas, Bronwyn A.; Maquat, Lynne E.

2016-01-01

Transposable elements (TEs) are both a boon and a bane to eukaryotic organisms, depending on where they integrate into the genome and how their sequences function once integrated. We focus on two types of TEs: long interspersed elements (LINEs) and short interspersed elements (SINEs). LINEs and SINEs are retrotransposons; that is, they transpose via an RNA intermediate. We discuss how LINEs and SINEs have expanded in eukaryotic genomes and contribute to genome evolution. An emerging body of evidence indicates that LINEs and SINEs function to regulate gene expression by affecting chromatin structure, gene transcription, pre-mRNA processing, or aspects of mRNA metabolism. We also describe how adenosine-to-inosine editing influences SINE function and how ongoing retrotransposition is countered by the body’s defense mechanisms. PMID:26912865

Transposable elements as genetic regulatory substrates in early development.

PubMed

Gifford, Wesley D; Pfaff, Samuel L; Macfarlan, Todd S

2013-05-01

The abundance and ancient origins of transposable elements (TEs) in eukaryotic genomes has spawned research into the potential symbiotic relationship between these elements and their hosts. In this review, we introduce the diversity of TEs, discuss how distinct classes are uniquely regulated in development, and describe how they appear to have been coopted for the purposes of gene regulation and the orchestration of a number of processes during early embryonic development. Although young, active TEs play an important role in somatic tissues and evolution, we focus mostly on the contributions of the older, fixed elements in mammalian genomes. We also discuss major challenges inherent in the study of TEs and contemplate future experimental approaches to further investigate how they coordinate developmental processes. Published by Elsevier Ltd.

Transposable elements as genetic regulatory substrates in early development

PubMed Central

Gifford, Wesley D.; Pfaff, Samuel L.; Macfarlan, Todd S.

2014-01-01

The abundance and ancient origins of transposable elements (TEs) in eukaryotic genomes has spawned research into the potential symbiotic relationship between these elements and their hosts. In this review, we introduce the diversity of TEs, discuss how distinct classes are uniquely regulated in development, and describe how they appear to have been coopted for the purposes of gene regulation and the orchestration of a number of processes during early embryonic development. Although young, active TEs play an important role in somatic tissues and evolution, we focus mostly on the contributions of the older, fixed elements in mammalian genomes. We also discuss major challenges inherent in the study of TEs and contemplate future experimental approaches to further investigate how they coordinate developmental processes. PMID:23411159

Potential roles for transposable elements in creating imprinted expression.

PubMed

Anderson, Sarah N; Springer, Nathan M

2018-04-01

Changes in gene expression can have profound effects on phenotype. Nature has provided many complex patterns of gene regulation such as imprinting. Imprinted genes exhibit differences in the expression of the maternal and paternal alleles, even though they reside in the same nucleus with access to the same trans-acting factors. Significant attention has been focused on the potential reasons that imprinted expression could be beneficial and stabilized by selection. However, less attention has focused on understanding how imprinted expression might arise or decay. We discuss the evidence for frequent turnover of imprinted expression based on evolutionary analyses in plants and the potential role for transposable elements (TEs) in creating imprinted expression patterns. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transposable elements in TDP-43-mediated neurodegenerative disorders.

PubMed

Li, Wanhe; Jin, Ying; Prazak, Lisa; Hammell, Molly; Dubnau, Josh

2012-01-01

Elevated expression of specific transposable elements (TEs) has been observed in several neurodegenerative disorders. TEs also can be active during normal neurogenesis. By mining a series of deep sequencing datasets of protein-RNA interactions and of gene expression profiles, we uncovered extensive binding of TE transcripts to TDP-43, an RNA-binding protein central to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Second, we find that association between TDP-43 and many of its TE targets is reduced in FTLD patients. Third, we discovered that a large fraction of the TEs to which TDP-43 binds become de-repressed in mouse TDP-43 disease models. We propose the hypothesis that TE mis-regulation contributes to TDP-43 related neurodegenerative diseases.

Tropical Africa as a cradle for horizontal transfers of transposable elements between species of the genera Drosophila and Zaprionus

PubMed Central

2011-01-01

We have recently reported numerous cases of horizontal transfers of transposable elements between species of drosophilids. These studies revealed a substantial number of horizontal transfers between species of the subgroup melanogaster of the genus Drosophila and between these species and species of the genus Zaprionus. In this review, these transfers and similar, previously reported events are discussed and reanalysed to portray the interrelationships between the species that allowed the occurrence of so many horizontal transfers. The paper also addresses problems that may arise in drawing inferences about the time period during which the horizontal transfers occurred and the factors that may be associated with these transfers are discussed. PMID:22312591

Regulatory activities of transposable elements: from conflicts to benefits

PubMed Central

Chuong, Edward B.; Elde, Nels C.; Feschotte, Cédric

2017-01-01

Transposable elements (TEs) are a prolific source of tightly regulated, biochemically active non-coding elements, such as transcription factor binding sites and non-coding RNAs. A wealth of recent studies reinvigorates the idea that these elements are pervasively co-opted for the regulation of host genes. We argue that the inherent genetic properties of TEs and conflicting relationships with their hosts facilitate their recruitment for regulatory functions in diverse genomes. We review recent findings supporting the long-standing hypothesis that the waves of TE invasions endured by organisms for eons have catalyzed the evolution of gene regulatory networks. We also discuss the challenges of dissecting and interpreting the phenotypic impact of regulatory activities encoded by TEs in health and disease. PMID:27867194

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

Mozrzymas, Marek; Horodecki, Michał; Studziński, Michał

We consider the structure of algebra of operators, acting in n-fold tensor product space, which are partially transposed on the last term. Using purely algebraical methods we show that this algebra is semi-simple and then, considering its regular representation, we derive basic properties of the algebra. In particular, we describe all irreducible representations of the algebra of partially transposed operators and derive expressions for matrix elements of the representations. It appears that there are two kinds of irreducible representations of the algebra. The first one is strictly connected with the representations of the group S(n − 1) induced by irreduciblemore » representations of the group S(n − 2). The second kind is structurally connected with irreducible representations of the group S(n − 1)« less

Performance enhancement of optical code-division multiple-access systems using transposed modified Walsh code

NASA Astrophysics Data System (ADS)

Sikder, Somali; Ghosh, Shila

2018-02-01

This paper presents the construction of unipolar transposed modified Walsh code (TMWC) and analysis of its performance in optical code-division multiple-access (OCDMA) systems. Specifically, the signal-to-noise ratio, bit error rate (BER), cardinality, and spectral efficiency were investigated. The theoretical analysis demonstrated that the wavelength-hopping time-spreading system using TMWC was robust against multiple-access interference and more spectrally efficient than systems using other existing OCDMA codes. In particular, the spectral efficiency was calculated to be 1.0370 when TMWC of weight 3 was employed. The BER and eye pattern for the designed TMWC were also successfully obtained using OptiSystem simulation software. The results indicate that the proposed code design is promising for enhancing network capacity.

Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas-Liquid Interface Temperature.

PubMed

Mohammadi, Morteza; Tembely, Moussa; Dolatabadi, Ali

2017-02-28

Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass-spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the resultant shear force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet contact time (e.g., 35% at a droplet Weber number of up to 140) was justified by the presence of a formed thin air layer underneath the impacting drop on the superhydrophobic surface (i.e., full slip condition). Finally, the droplet wetting model was also further developed to account for low temperature through the incorporation of classical nucleation theory. Homogeneous ice nucleation was integrated into the model through the concept of the reduction of the supercooled water drop surface tension as a function of the gas-liquid interface temperature, which was directly correlated with the Nusselt number of incoming air flow. It was shown that the experimental results was qualitatively predicted by the proposed model under all supercooling conditions (i.e., from -10 to -30 °C).

PLSS Scale Demonstration of MTSA Temperature Swing Adsorption Bed Concept for CO2 Removal/Rejection

NASA Technical Reports Server (NTRS)

Iacomini, Christine S.; Powers, Aaron; Paul, Heather L.

2009-01-01

Metabolic heat regenerated temperature swing adsorption (MTSA) incorporated into a portable life support system (PLSS) is being explored as a viable means of removing and rejecting carbon dioxide (CO2) from an astronaut s ventilation loop. Sorbent pellets used in previous work are inherently difficult to quickly heat and cool. Further, their use in packed beds create large undesirable pressure drop. Thus work has been done to assess the application and performance of aluminum foam wash coated with a layer of sorbent. A to-scale sorbent bed, as envisioned studying use by a Martian PLSS, was designed, built, and tested. Performance of the assembly in regards to CO2 adsorption and pressure drop were assessed and the results are presented.

Cavity optomechanics in a levitated helium drop

NASA Astrophysics Data System (ADS)

Childress, L.; Schmidt, M. P.; Kashkanova, A. D.; Brown, C. D.; Harris, G. I.; Aiello, A.; Marquardt, F.; Harris, J. G. E.

2017-12-01

We describe a proposal for a type of optomechanical system based on a drop of liquid helium that is magnetically levitated in vacuum. In the proposed device, the drop would serve three roles: its optical whispering-gallery modes would provide the optical cavity, its surface vibrations would constitute the mechanical element, and evaporation of He atoms from its surface would provide continuous refrigeration. We analyze the feasibility of such a system in light of previous experimental demonstrations of its essential components: magnetic levitation of mm-scale and cm-scale drops of liquid He , evaporative cooling of He droplets in vacuum, and coupling to high-quality optical whispering-gallery modes in a wide range of liquids. We find that the combination of these features could result in a device that approaches the single-photon strong-coupling regime, due to the high optical quality factors attainable at low temperatures. Moreover, the system offers a unique opportunity to use optical techniques to study the motion of a superfluid that is freely levitating in vacuum (in the case of 4He). Alternatively, for a normal fluid drop of 3He, we propose to exploit the coupling between the drop's rotations and vibrations to perform quantum nondemolition measurements of angular momentum.

Aerosol partitioning in natural mixed-phase clouds

NASA Astrophysics Data System (ADS)

Henning, S.; Bojinski, S.; Diehl, K.; Ghan, S.; Nyeki, S.; Weingartner, E.; Wurzler, S.; Baltensperger, U.

2004-03-01

In situ aerosol and cloud drop microphysical measurements at a high-alpine site are used to investigate aerosol partitioning between cloud and interstitial phases in natural, mid-latitude, mixed-phase clouds. Measurements indicate a decrease in the activated aerosol fraction (FN) for particle diameters dP > 100 nm with cloud temperature from FN ~ 0.54 in summer liquid-phase clouds to FN ~ 0.08 in winter mixed-phase clouds. The latter may be attributed to the Bergeron-Findeisen mechanism whereby ice crystals grow at the expense of liquid water drops, releasing formerly activated aerosols back into the interstitial phase. This provides a means to distinguish the indirect effects of aerosols on drops and ice crystals.

A comprehensive analysis of the evaporation of a liquid spherical drop.

PubMed

Sobac, B; Talbot, P; Haut, B; Rednikov, A; Colinet, P

2015-01-15

In this paper, a new comprehensive analysis of a suspended drop of a pure liquid evaporating into air is presented. Based on mass and energy conservation equations, a quasi-steady model is developed including diffusive and convective transports, and considering the non-isothermia of the gas phase. The main original feature of this simple analytical model lies in the consideration of the local dependence of the physico-chemical properties of the gas on the gas temperature, which has a significant influence on the evaporation process at high temperatures. The influence of the atmospheric conditions on the interfacial evaporation flux, molar fraction and temperature is investigated. Simplified versions of the model are developed to highlight the key mechanisms governing the evaporation process. For the conditions considered in this work, the convective transport appears to be opposed to the evaporation process leading to a decrease of the evaporation flux. However, this effect is relatively limited, the Péclet numbers happening to be small. In addition, the gas isothermia assumption never appears to be valid here, even at room temperature, due to the large temperature gradient that develops in the gas phase. These two conclusions are explained by the fact that heat transfer from the gas to the liquid appears to be the step limiting the evaporation process. Regardless of the complexity of the developed model, yet excluding extremely small droplets, the square of the drop radius decreases linearly over time (R(2) law). The assumptions of the model are rigorously discussed and general criteria are established, independently of the liquid-gas couple considered. Copyright © 2014 Elsevier Inc. All rights reserved.

Nuclear Engineering Computer Modules, Thermal-Hydraulics, TH-3: High Temperature Gas Cooled Reactor Thermal-Hydraulics.

ERIC Educational Resources Information Center

Reihman, Thomas C.

This learning module is concerned with the temperature field, the heat transfer rates, and the coolant pressure drop in typical high temperature gas-cooled reactor (HTGR) fuel assemblies. As in all of the modules of this series, emphasis is placed on developing the theory and demonstrating its use with a simplified model. The heart of the module…

An improved oxygen diffusion model to explain the effect of low-temperature baking on high field losses in niobium superconducting cavities

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

Ciovati, Gianluigi

Radio-frequency (RF) superconducting cavities made of high purity niobium are widely used to accelerate charged particle beams in particle accelerators. The major limitation to achieve RF field values approaching the theoretical limit for niobium is represented by ''anomalous'' losses which degrade the quality factor of the cavities starting at peak surface magnetic fields of about 100 mT, in absence of field emission. These high field losses are often referred to as ''Q-drop''. It has been observed that the Q-drop is drastically reduced by baking the cavities at 120 C for about 48 h under ultrahigh vacuum. An improved oxygen diffusionmore » model for the niobium-oxide system is proposed to explain the benefit of the low-temperature baking on the Q-drop in niobium superconducting rf cavities. The model shows that baking at 120 C for 48 h allows oxygen to diffuse away from the surface, and therefore increasing the lower critical field towards the value for pure niobium.« less

Relationship of starch changes to puffing expansion of parboiled rice.

PubMed

Mahanta, Charu Lata; Bhattacharya, K R

2010-03-01

'Intan' variety of paddy (Oryza sativa) was tested for puffing. It was parboiled under a wide range of paddy moisture content, steaming pressure and time, as also temperature and time of sand heating. The resulting milled rices were studied for their diverse properties including puffing. Indices of starch changes in the samples were calculated as: (1) gelatinisation index from the solubility of amylose in 0.2 N KOH; (2) amylopectin retrogradation from the post-production drop in room-temperature hydration power of the parboiled paddy during air-drying, (3) thermal breakdown of starch from the drop in gel permeation chromatographic fraction I of starch; lipid-amylose complexation indirectly from (4) drop in rate of water uptake during cooking and (5) cooked-rice firmness. It was found that the puffing expansion was very highly correlated with the combined above 5 indices of starch changes, as much as 90% of the variation in puffing being explainable on that basis. Puffing was promoted by gelatinisation as well as lipid-amylose complexation, but was retarded by amylopectin retrogradation and probably starch breakdown.

Regenerator filled with a matrix of polycrystalline iron whiskers

NASA Astrophysics Data System (ADS)

Eder, F. X.; Appel, H.

1982-08-01

In thermal regenerators, parameters were optimized: convection coefficient, surface of heat accumulating matrix, matrix density and heat capacity, and frequency of cycle inversions. The variation of heat capacity with working temperature was also computed. Polycrystalline iron whiskers prove a good compromise as matrix for heat regenerators at working temperatures ranging from 300 to 80 K. They were compared with wire mesh screens and microspheres of bronze and stainless steel. For theses structures and materials, thermal conductivity, pressure drop, heat transfer and yield were calculated and related to the experimental values. As transport heat gas, helium, argon, and dry nitrogen were applied at pressures up to 20 bar. Experimental and theoretical studies result in a set of formulas for calculating pressure drop, heat capacity, and heat transfer rate for a given thermal regenerator in function of mass flow. It is proved that a whisker matrix has an efficiency that depends strongly on gas pressure and composition. Iron whiskers make a good matrix with heat capacities of kW/cu cm per K, but their relative high pressure drop may, at low pressures, be a limitation. A regenerator expansion machine is described.

R245fa Flow Boiling inside a 4.2 mm ID Microfin Tube

NASA Astrophysics Data System (ADS)

Longo, G. A.; Mancin, S.; Righetti, G.; Zilio, C.

2017-11-01

This paper presents the R245fa flow boiling heat transfer and pressure drop measurements inside a mini microfin tube with internal diameter at the fin tip of 4.2 mm, having 40 fins, 0.15 mm high with a helix angle of 18°. The tube was brazed inside a copper plate and electrically heated from the bottom. Sixteen T-type thermocouples are located in the copper plate to monitor the wall temperature. The experimental measurements were carried out at constant mean saturation temperature of 30 °C, by varying the refrigerant mass velocity between 100 kg m-2 s-1 and 300 kg m-2 s-1, the vapour quality from 0.15 to 0.95, at two different heat fluxes: 30 and 60 kW m-2. The experimental results are presented in terms of two-phase heat transfer coefficient, onset dryout vapour quality, and frictional pressure drop. Moreover, the experimental measurements are compared against the most updated models for boiling heat transfer coefficient and frictional pressure drop estimations available in the open literature for microfin tubes.

Effect of superficial velocity on vaporization pressure drop with propane in horizontal circular tube

NASA Astrophysics Data System (ADS)

Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.

2016-06-01

Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on vaporization pressure drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing vapor superficial velocity, and then increasing pressure drop. The present experimental results were evaluated with some existing correlations of pressure drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.

Temperature Scaling Law for Quantum Annealing Optimizers.

PubMed

Albash, Tameem; Martin-Mayor, Victor; Hen, Itay

2017-09-15

Physical implementations of quantum annealing unavoidably operate at finite temperatures. We point to a fundamental limitation of fixed finite temperature quantum annealers that prevents them from functioning as competitive scalable optimizers and show that to serve as optimizers annealer temperatures must be appropriately scaled down with problem size. We derive a temperature scaling law dictating that temperature must drop at the very least in a logarithmic manner but also possibly as a power law with problem size. We corroborate our results by experiment and simulations and discuss the implications of these to practical annealers.

NASA Snaps Picture of Eastern U.S. in a Record-Breaking "Freezer"

NASA Image and Video Library

2015-02-20

NASA's Terra satellite captured an image of the snow-covered eastern U.S. that looks like the states have been sitting in a freezer. In addition to the snow cover, Arctic and Siberian air masses have settled in over the Eastern U.S. triggering many record low temperatures in many states. On Feb. 19 at 16:40 UTC (11:40 a.m. EST), the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument that flies aboard NASA's Terra satellite captured a picture of the snowy landscape. The snow cover combined with the frosty air mass made the eastern U.S. feel like the inside of freezer. The MODIS image was created at NASA's Goddard Space Flight Center in Greenbelt, Maryland. On the morning of Feb. 20, NOAA's Weather Prediction Center (WPC) noted, "There were widespread subzero overnight lows Thursday night (Feb. 19) extending from Illinois to western Virginia, and numerous record lows were set. Bitterly-cold arctic air is setting numerous temperature records across the eastern U.S. and will keep temperatures well below normal on Friday (Feb. 20)." In Baltimore, Maryland, a low temperature of 1F broke the record low for coldest morning recorded at the Thurgood Marshall Baltimore Washington-International Airport. In Louisville, Kentucky, temperatures dropped to -6F, breaking the old record low of 0F, according to meteorologist Brian Goode of WAVE-TV. Meanwhile, Richmond Kentucky bottomed out at a frigid -32F. In North Carolina, a record low temperature was set at Charlotte where the overnight temperature bottomed out at 7F breaking the old record of 13F in 1896. In Asheville, temperatures dropped to just 4F breaking the old record of 10F in 1979. Temperature records for Asheville extend back to 1876. Several records were also broken in Georgia, according to Matt Daniel, a meteorologist at WMAZ-TV, Macon Georgia, who cited data from the National Weather Service. Daniel said that Macon set a new record low when the temperature dropped to 18F, beating the previous record of 21F set in 1958. Athens broke a new record low, too dropping to 14F and beating the old record of 18F set in 1958/1928. NOAA's NPC noted that "Highs on Friday (Feb. 20) will struggle to get out of the teens from the Ohio Valley to the Mid-Atlantic region. After Friday, temperatures are forecast to moderate and get closer to February averages as a storm system approaches from the west." Image Credit: NASA Goddard MODIS Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Microdrop preparation factors influence culture-media osmolality, which can impair mouse embryo preimplantation development.

PubMed

Swain, J E; Cabrera, L; Xu, X; Smith, G D

2012-02-01

Because media osmolality can impact embryo development, the effect of conditions during microdrop preparation on osmolality was examined. Various sizes of microdrops were prepared under different laboratory conditions. Drops were pipetted directly onto a dish and covered by oil (standard method) or pipetted on the dish, overlaid with oil before removing the underlying media and replaced with fresh media (wash-drop method). Drops were made at 23°C or on a heated stage (37°C) and with or without airflow. Osmolality was assessed at 5 min and 24h. The biological impact of osmolality change was demonstrated by culturing 1-cell mouse embryos in media with varying osmolality. Reduced drop volume, increased temperature and standard method were associated with a significant increase in osmolality at both 5 min and 24h (P-values <0.001, <0.0001 and <0.0001, respectively). There was a significant interaction between airflow, decreased volume, increased temperature and standard method that caused a significant increase in osmolality (40mOsm/kg) compared with controls (P<0.04). There was no significant change in osmolality over time. Mouse embryo development was significantly reduced in media with elevated osmolality (>310mOsm/kg; P<0.05). Procedures in the IVF laboratory can alter osmolality and impact embryo development. Copyright © 2011 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

The genetic architecture of Drosophila sensory bristle number.

PubMed Central

Dilda, Christy L; Mackay, Trudy F C

2002-01-01

We have mapped quantitative trait loci (QTL) for Drosophila mechanosensory bristle number in six recombinant isogenic line (RIL) mapping populations, each of which was derived from an isogenic chromosome extracted from a line selected for high or low, sternopleural or abdominal bristle number and an isogenic wild-type chromosome. All RILs were evaluated as male and female F(1) progeny of crosses to both the selected and the wild-type parental chromosomes at three developmental temperatures (18 degrees, 25 degrees, and 28 degrees ). QTL for bristle number were mapped separately for each chromosome, trait, and environment by linkage to roo transposable element marker loci, using composite interval mapping. A total of 53 QTL were detected, of which 33 affected sternopleural bristle number, 31 affected abdominal bristle number, and 11 affected both traits. The effects of most QTL were conditional on sex (27%), temperature (14%), or both sex and temperature (30%). Epistatic interactions between QTL were also common. While many QTL mapped to the same location as candidate bristle development loci, several QTL regions did not encompass obvious candidate genes. These features are germane to evolutionary models for the maintenance of genetic variation for quantitative traits, but complicate efforts to understand the molecular genetic basis of variation for complex traits. PMID:12524340

Measured Performance of a Low Temperature Air Source Heat Pump

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

R.K. Johnson

2013-09-01

A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.

Aerodynamic drag characterization and deposition studies of irregular particles. Part 3: Analysis of flow and temperature field inside the Combustion Deposition Entrained Reactor (CDER)

NASA Astrophysics Data System (ADS)

Celik, I.; Katragadda, S.; Nagarajan, R.

1990-01-01

An experimental and numerical analysis was performed of the temperature and flow field involved in co-axial, confined, non-reacting heated jets in a drop tube reactor. An electrically heated 2-inch (50.8 mm) diameter drop tube reactor was utilized to study the jet characteristics. Profiles of gas temperature, typically in the range of 800 to 1600 K were measured in the mixing zone of the jet with a K-Type thermocouple. Measured temperatures were corrected for conduction, convection, and radiation heat losses. Because of limited access to the mixing zone, characterization of the flow field at high temperatures with laser Doppler or hot wire anemometry were impractical. A computer program which solves the full equations of motion and energy was employed to simulate the temperature and flow fields. The location of the recirculation region, the flow regimes, and the mixing phenomena were studied. The wall heating, laminar and turbulent flow regimes were considered in the simulations. The predictions are in fairly good agreement with the corrected temperature measurements provided that the flow is turbulent. The results of this study demonstrate how a numerical method and measurement can be used together to analyze the flow conditions inside a reactor which has limited access because of very high temperatures.

Micro-explosion of compound drops

NASA Astrophysics Data System (ADS)

Chen, Chun-Kuei; Lin, Ta-Hui

2014-08-01

Introducing water into spray combustion systems, by either water-in-oil emulsification or supplementary water injection, is one of the major techniques for combustion improvement and NOx reduction. Plentiful researches are available on combustion of water-in-oil emulsion fuel drops. The emulsified liquid is a heterogeneous mixture of immiscible liquids. One component forms the continuous phase and the other component forms the discrete phase. The discrete phase consists of globules of the one fluid that are suspended in the continuous phase fluid. Water-in-oil emulsions are commonly considered for combustion applications because emulsions can result in micro-explosion, thereby reducing the average drop diameter to enhance liquid vaporization, and suppressing the formation of soot and NOx. However, the water addition generally does not exceed about 20% for smooth engine operations[!, 21. The combustion characteristics and micro-explosion of emulsion drop were studied by many researchers. The micro-explosion of water in fuel emulsion drops was caused by very fast growth of superheated water vapor bubbles, its superheat limits must be lower than the boiling point temperature of the fuel. These bubbles were primarily governed by the pressure difference between the superheated vapor and the liquid, and by the inertia imparted to the liquid by the motion of the bubble surface[3 6 In this study, we used a coaxial nozzle to generation the multi-component drop. The different type of water-in-oil fuel drops called the compound drops. Unlike an emulsion drop, a compound drop consists of a water core and a fuel shell, which can originate from the phase separation of emulsion[7, 81 or a water drop colliding with a fuel drop[9, 101 Burning and micro-explosion of compound drops have been found to be distinct from those of emulsion drops[9-111 Wang et al.[9 , 101 studied the combustion characteristics of collision merged alkane-water drops. The merged drops appeared in adhesive and inserted manners. The drop ignition delay time increased with increasing water content. The average burning rate of alkane-water drops decreased with increasing water content. In the burning process, hexadecane-water drops exhibited flash vaporization or flame extinction. Heterogeneous explosion was occasionally observed in drops with trapped air bubbles. The air bubbles were assumed to be the nucleation points of the heterogeneous explosions. Chen and Lin[11 studied the characteristics of water-in-dodecane compound drop with different water content, diameter of drop and environmental oxygen concentration. The vaporization rate increased with increasing environmental oxygen concentration. The compound drops micro-exploded during the burning process in a random way. The number of micro-explosions was majorly influenced by drop diameter, followed by environmental oxygen concentration. Water content had a weaker effect on micro-explosion. As available literature and research results of compound drop burning are scarce, their combustion and micro-explosion behaviors are still poorly understood. In this regard, we changed the drop nature as compound drops to study their combustion characteristics and micro-explosion phenomena.

Impact Delamination and Fracture in Aluminum/Acrylic Sandwich Plates

NASA Technical Reports Server (NTRS)

Liaw, Benjamin; Zeichner, Glenn; Liu, Yanxiong; Bowles, Kenneth J. (Technical Monitor)

2000-01-01

Impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F. Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.

Alternate-Fueled Combustor-Sector Performance

NASA Technical Reports Server (NTRS)

Thomas, Anna E.; Saxena, Nikita T.; Shouse, Dale T.; Neuroth, Craig; Hendricks, Robert C.; Lynch, Amy; Frayne, Charles W.; Stutrud, Jeffrey S.; Corporan, Edwin; Hankins, Terry

2012-01-01

In order to realize alternative fueling for military and commercial use, the industry has set forth guidelines that must be met by each fuel. These aviation fueling requirements are outlined in MILDTL- 83133F(2008) or ASTM D 7566 Annex (2011) standards, and are classified as drop-in fuel replacements. This paper provides combustor performance data for synthetic-paraffinic-kerosene- (SPK-) type (Fisher-Tropsch (FT)) fuel and blends with JP-8+100, relative to JP-8+100 as baseline fueling. Data were taken at various nominal inlet conditions: 75 psia (0.52 MPa) at 500 F (533 K), 125 psia (0.86 MPa) at 625 F (603 K), 175 psia (1.21 MPa) at 725 F (658 K), and 225 psia (1.55 MPa) at 790 F (694 K). Combustor performance analysis assessments were made for the change in flame temperatures, combustor efficiency, wall temperatures, and exhaust plane temperatures at 3%, 4%, and 5% combustor pressure drop (% delta P) for fuel: air ratios (F/A) ranging from 0.010 to 0.025. Significant general trends show lower liner temperatures and higher flame and combustor outlet temperatures with increases in FT fueling relative to JP-8+100 fueling. The latter affects both turbine efficiency and blade/vane life.

Mallard hatching from an egg cracked by freezing

USGS Publications Warehouse

Greenwood, R.J.

1969-01-01

The eggs of early-nesting waterfowl in North Dakota are frequently exposed to subfreezing temperatures. Mallards (Anas platyrhynchos) and Pintail (Anas acuta), normally the first ducks to arrive in the spring, begin limited early nesting in min-April. Nighttime temperatures during this period frequently drop below freezing, and late spring blizzards are not unusual.

PILOT-SCALE PARAMETRIC TESTING OF SPRAY DRYER SO2 SCRUBBER FOR LOW-TO-MODERATE SULFUR COAL UTILITY APPLICATIONS

EPA Science Inventory

The report gives results of a comprehensive, pilot, dry, SO2 scrubbing test program to determine the effects of process variables on SO2 removal. In the spray dryer, stoichiometric ratio, flue gas temperature approach to adiabatic saturation, and temperature drop across the spray...

The impacts of climate change on the abundance and distribution of the Spotted Wing Drosophila (Drosophila suzukii) in the United States and Canada

PubMed Central

Arteca, Ellen M.; Newman, Jonathan A.

2017-01-01

D. suzukii is a relatively recent and destructive pest species to the North American soft-skinned fruit industry. Understanding this species’ potential to shift in abundance and range due to changing climate is an important part of an effective mitigation and management strategy. We parameterized a temperature-driven D. suzukii population dynamics model using temperature data derived from several Global Circulation Models (CMIP5) with a range of relative concentration pathway (RCP) predictions. Mean consensus between the models suggest that without adaptation to both higher prolonged temperatures and higher short-term temperature events D. suzukii population levels are likely to drop in currently higher-risk regions. The potential drop in population is evident both as time progresses and as the severity of the RCP scenario increases. Some regions, particularly in northern latitudes, may experience increased populations due to milder winter and more developmentally-ideal summer conditions, but many of these regions are not currently known for soft-skinned fruit production and so the effects of this population increase may not have a significant impact. PMID:28396828

An experimental and analytical investigation of thermoacoustic convection heat transfer in gravity and zero-gravity environments

NASA Technical Reports Server (NTRS)

Parang, Masood

1986-01-01

An experimental and analytical study of Thermoacoustic Convection heat transfer in gravity and zero-gravity environments is presented. The experimental apparatus consisted of a cylinder containing air as a fluid. The side wall of the cylinder was insulated while the bottom wall was allowed to remain at the ambient temperature. The enclosed air was rapidly heated by the top surface which consisted of a thin stainless steel foil connected to a battery pack as the power source. Thermocouples were used to measure the transient temperature of the air on the axis of the cylinder. The ouput of the thermocouples was displayed on digital thermometers and the temperature displays were recorded on film using a high-speed movie camera. Temperature measurements were obtained in the zero-gravity environment by dropping the apparatus in the 2-Seconds Zero-Gravity Drop Tower Facilities of NASA Lewis Research Center. In addition, experiments were also performed in the gravity environment and the results are compared in detail with those obtained under zero-gravity conditions.

piRNAs and their diverse roles: a transposable element-driven tactic for gene regulation?

PubMed

Sarkar, Arpita; Volff, Jean-Nicolas; Vaury, Chantal

2017-02-01

P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) are small, noncoding RNAs known for silencing transposable elements (TEs) in the germline of animals. Most genomes host TEs, which are notorious for mobilizing themselves and endangering survival of the host if not controlled. By silencing TEs in the germline, piRNAs prevent harmful mutations from being passed on to the next generation. How piRNAs are generated and how they silence TEs were the focus of researchers ever since their discovery. Now a spate of recent papers are beginning to tell us that piRNAs can play roles beyond TE silencing and are involved in diverse cellular processes from mRNA regulation to development or genome rearrangement. In this review, we discuss some of these recently reported roles. Data on these new roles are often rudimentary, and the involvement of piRNAs in these processes is yet to be definitely established. What is interesting is that the reports are on animals widely separated on the phylogenetic tree of life and that piRNAs were also found outside the gonadal tissues. Some of these piRNAs map to TE sequences, prompting us to hypothesize that genomes may have co-opted the TE-derived piRNA system for their own regulation.-Sarkar, A., Volff, J.-N., Vaury, C. piRNAs and their diverse roles: a transposable element-driven tactic for gene regulation? © FASEB.

LINE dancing in the human genome: transposable elements and disease.

PubMed

Belancio, Victoria P; Deininger, Prescott L; Roy-Engel, Astrid M

2009-10-27

Transposable elements (TEs) have been consistently underestimated in their contribution to genetic instability and human disease. TEs can cause human disease by creating insertional mutations in genes, and also contributing to genetic instability through non-allelic homologous recombination and introduction of sequences that evolve into various cis-acting signals that alter gene expression. Other outcomes of TE activity, such as their potential to cause DNA double-strand breaks or to modulate the epigenetic state of chromosomes, are less fully characterized. The currently active human transposable elements are members of the non-LTR retroelement families, LINE-1, Alu (SINE), and SVA. The impact of germline insertional mutagenesis by TEs is well established, whereas the rate of post-insertional TE-mediated germline mutations and all forms of somatic mutations remain less well quantified. The number of human diseases discovered to be associated with non-allelic homologous recombination between TEs, and particularly between Alu elements, is growing at an unprecedented rate. Improvement in the technology for detection of such events, as well as the mounting interest in the research and medical communities in resolving the underlying causes of the human diseases with unknown etiology, explain this increase. Here, we focus on the most recent advances in understanding of the impact of the active human TEs on the stability of the human genome and its relevance to human disease.

GrTEdb: the first web-based database of transposable elements in cotton (Gossypium raimondii).

PubMed

Xu, Zhenzhen; Liu, Jing; Ni, Wanchao; Peng, Zhen; Guo, Yue; Ye, Wuwei; Huang, Fang; Zhang, Xianggui; Xu, Peng; Guo, Qi; Shen, Xinlian; Du, Jianchang

2017-01-01

Although several diploid and tetroploid Gossypium species genomes have been sequenced, the well annotated web-based transposable elements (TEs) database is lacking. To better understand the roles of TEs in structural, functional and evolutionary dynamics of the cotton genome, a comprehensive, specific, and user-friendly web-based database, Gossypium raimondii transposable elements database (GrTEdb), was constructed. A total of 14 332 TEs were structurally annotated and clearly categorized in G. raimondii genome, and these elements have been classified into seven distinct superfamilies based on the order of protein-coding domains, structures and/or sequence similarity, including 2929 Copia-like elements, 10 368 Gypsy-like elements, 299 L1 , 12 Mutators , 435 PIF-Harbingers , 275 CACTAs and 14 Helitrons . Meanwhile, the web-based sequence browsing, searching, downloading and blast tool were implemented to help users easily and effectively to annotate the TEs or TE fragments in genomic sequences from G. raimondii and other closely related Gossypium species. GrTEdb provides resources and information related with TEs in G. raimondii , and will facilitate gene and genome analyses within or across Gossypium species, evaluating the impact of TEs on their host genomes, and investigating the potential interaction between TEs and protein-coding genes in Gossypium species. http://www.grtedb.org/. © The Author(s) 2017. Published by Oxford University Press.

Transposable elements as agents of rapid adaptation may explain the genetic paradox of invasive species.

PubMed

Stapley, Jessica; Santure, Anna W; Dennis, Stuart R

2015-05-01

Rapid adaptation of invasive species to novel habitats has puzzled evolutionary biologists for decades, especially as this often occurs in the face of limited genetic variability. Although some ecological traits common to invasive species have been identified, little is known about the possible genomic/genetic mechanisms that may underlie their success. A common scenario in many introductions is that small founder population sizes will often lead to reduced genetic diversity, but that invading populations experience large environmental perturbations, such as changes in habitat and environmental stress. Although sudden and intense stress is usually considered in a negative context, these perturbations may actually facilitate rapid adaptation by affecting genome structure, organization and function via interactions with transposable elements (TEs), especially in populations with low genetic diversity. Stress-induced changes in TE activity can alter gene action and can promote structural variation that may facilitate the rapid adaptation observed in new environments. We focus here on the adaptive potential of TEs in relation to invasive species and highlight their role as powerful mutational forces that can rapidly create genetic diversity. We hypothesize that activity of transposable elements can explain rapid adaptation despite low genetic variation (the genetic paradox of invasive species), and provide a framework under which this hypothesis can be tested using recently developed and emerging genomic technologies. © 2015 John Wiley & Sons Ltd.

Single molecule counting and assessment of random molecular tagging errors with transposable giga-scale error-correcting barcodes.

PubMed

Lau, Billy T; Ji, Hanlee P

2017-09-21

RNA-Seq measures gene expression by counting sequence reads belonging to unique cDNA fragments. Molecular barcodes commonly in the form of random nucleotides were recently introduced to improve gene expression measures by detecting amplification duplicates, but are susceptible to errors generated during PCR and sequencing. This results in false positive counts, leading to inaccurate transcriptome quantification especially at low input and single-cell RNA amounts where the total number of molecules present is minuscule. To address this issue, we demonstrated the systematic identification of molecular species using transposable error-correcting barcodes that are exponentially expanded to tens of billions of unique labels. We experimentally showed random-mer molecular barcodes suffer from substantial and persistent errors that are difficult to resolve. To assess our method's performance, we applied it to the analysis of known reference RNA standards. By including an inline random-mer molecular barcode, we systematically characterized the presence of sequence errors in random-mer molecular barcodes. We observed that such errors are extensive and become more dominant at low input amounts. We described the first study to use transposable molecular barcodes and its use for studying random-mer molecular barcode errors. Extensive errors found in random-mer molecular barcodes may warrant the use of error correcting barcodes for transcriptome analysis as input amounts decrease.

Fate of sulfur mustard on soil: Evaporation, degradation, and vapor emission.

PubMed

Jung, Hyunsook; Kah, Dongha; Chan Lim, Kyoung; Lee, Jin Young

2017-01-01

After application of sulfur mustard to the soil surface, its possible fate via evaporation, degradation following absorption, and vapor emission after decontamination was studied. We used a laboratory-sized wind tunnel, thermal desorber, gas chromatograph-mass spectrometry (GC-MS), and 13 C nuclear magnetic resonance ( 13 C NMR) for systematic analysis. When a drop of neat HD was deposited on the soil surface, it evaporated slowly while being absorbed immediately into the matrix. The initial evaporation or drying rates of the HD drop were found to be power-dependent on temperature and initial drop volume. Moreover, drops of neat HD, ranging in size from 1 to 6 μL, applied to soil, evaporated at different rates, with the smaller drops evaporating relatively quicker. HD absorbed into soil remained for a month, degrading eventually to nontoxic thiodiglycol via hydrolysis through the formation of sulfonium ions. Finally, a vapor emission test was performed for HD contaminant after a decontamination process, the results of which suggest potential risk from the release of trace chemical quantities of HD into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hepatitis C virus maintains infectivity for weeks after drying on inanimate surfaces at room temperature: implications for risks of transmission.

PubMed

Paintsil, Elijah; Binka, Mawuena; Patel, Amisha; Lindenbach, Brett D; Heimer, Robert

2014-04-15

Healthcare workers may come into contact with fomites that contain infectious hepatitis C virus (HCV) during preparation of plasma or following placement or removal of venous lines. Similarly, injection drugs users may come into contact with fomites. Hypothesizing that prolonged viability of HCV in fomites may contribute significantly to incidence, we determined the longevity of virus infectivity and the effectiveness of antiseptics. We determined the volume of drops misplaced during transfer of serum or plasma. Aliquots equivalent to the maximum drop volume of plasma spiked with the 2a HCV reporter virus were loaded into 24-well plates. Plates were stored uncovered at 3 temperatures: 4°C, 22°C, and 37°C for up to 6 weeks before viral infectivity was determined in a microculture assay. The mean volume of an accidental drop was 29 µL (min-max of 20-33 µL). At storage temperatures 4°C and 22°C, we recovered viable HCV from the low-titer spots for up to 6 weeks of storage. The rank order of HCV virucidal activity of commonly used antiseptics was bleach (1:10) > cavicide (1:10) > ethanol (70%). The hypothesis of potential transmission from fomites was supported by the experimental results. The anti-HCV activity of commercial antiseptics varied.

Hepatitis C Virus Maintains Infectivity for Weeks After Drying on Inanimate Surfaces at Room Temperature: Implications for Risks of Transmission

PubMed Central

Paintsil, Elijah; Binka, Mawuena; Patel, Amisha; Lindenbach, Brett D.; Heimer, Robert

2014-01-01

Background. Healthcare workers may come into contact with fomites that contain infectious hepatitis C virus (HCV) during preparation of plasma or following placement or removal of venous lines. Similarly, injection drugs users may come into contact with fomites. Hypothesizing that prolonged viability of HCV in fomites may contribute significantly to incidence, we determined the longevity of virus infectivity and the effectiveness of antiseptics. Methods. We determined the volume of drops misplaced during transfer of serum or plasma. Aliquots equivalent to the maximum drop volume of plasma spiked with the 2a HCV reporter virus were loaded into 24-well plates. Plates were stored uncovered at 3 temperatures: 4°C, 22°C, and 37°C for up to 6 weeks before viral infectivity was determined in a microculture assay. Results. The mean volume of an accidental drop was 29 µL (min–max of 20–33 µL). At storage temperatures 4°C and 22°C, we recovered viable HCV from the low-titer spots for up to 6 weeks of storage. The rank order of HCV virucidal activity of commonly used antiseptics was bleach (1:10) > cavicide (1:10) > ethanol (70%). Conclusions. The hypothesis of potential transmission from fomites was supported by the experimental results. The anti-HCV activity of commercial antiseptics varied. PMID:24273176

An ionic liquid as a solvent for headspace single drop microextraction of chlorobenzenes from water samples.

PubMed

Vidal, Lorena; Psillakis, Elefteria; Domini, Claudia E; Grané, Nuria; Marken, Frank; Canals, Antonio

2007-02-12

A headspace single-drop microextraction (HS-SDME) procedure using room temperature ionic liquid and coupled to high-performance liquid chromatography capable of quantifying trace amounts of chlorobenzenes in environmental water samples is proposed. A Plackett-Burman design for screening was carried out in order to determine the significant experimental conditions affecting the HS-SDME process (namely drop volume, aqueous sample volume, stirring speed, ionic strength, extraction time and temperature), and then a central composite design was used to optimize the significant conditions. The optimum experimental conditions found from this statistical evaluation were: a 5 microL microdrop of 1-butyl-3-methylimidazolium hexafluorophosphate, exposed for 37 min to the headspace of a 10 mL aqueous sample placed in a 15 mL vial, stirred at 1580 rpm at room temperature and containing 30% (w/v) NaCl. The calculated calibration curves gave a high level of linearity for all target analytes with correlation coefficients ranging between 0.9981 and 0.9997. The repeatability of the proposed method, expressed as relative standard deviation, varied between 1.6 and 5.1% (n=5). The limits of detection ranged between 0.102 and 0.203 microg L(-1). Matrix effects upon extraction were evaluated by analysing spiked tap and river water as well as effluent water samples originating from a municipal wastewater treatment plant.

Experimental evidence for modifying the current physical model for ice accretion on aircraft surfaces

NASA Technical Reports Server (NTRS)

Olsen, W.; Walker, E.

1986-01-01

Closeup movies, still photographs, and other experimental data suggest that the current physical model for ice accretion needs significant modification. At aircraft airspeeds there was no flow of liquid over the surface of the ice after a short initial flow, even at barely subfreezing temperatures. Instead, there were very large stationary drops on the ice surface that lose water from their bottoms by freezing and replenish their liquid by catching the microscopic cloud droplets. This observation disagrees with the existing physical model, which assumes there is a thin liquid film continuously flowing over the ice surface. With no such flow, the freezing-fraction concept of the model fails when a mass balance is performed on the surface water. Rime ice does, as the model predicts, form when the air temperature is low enough to cause the cloud droplets to freeze almost immediately on impact. However, the characteristic shapes of horn-glaze ice or rime ice are primarily caused by the ice shape affecting the airflow locally and consequently the droplet catch and the resulting ice shape. Ice roughness greatly increases the heat transfer coefficient, stops the movement of drops along the surface, and may also affect the airflow initially and thereby the droplet catch. At high subreezing temperatures the initial flow and shedding of surface drops have a large effect on the ice shape. At the incipient freezing limit, no ice forms.

Investigation on heat transfer characteristics and flow performance of Methane at supercritical pressures

NASA Astrophysics Data System (ADS)

Xian, Hong Wei; Oumer, A. N.; Basrawi, F.; Mamat, Rizalman; Abdullah, A. A.

2018-04-01

The aim of this study is to investigate the heat transfer and flow characteristic of cryogenic methane in regenerative cooling system at supercritical pressures. The thermo-physical properties of supercritical methane were obtained from the National institute of Standards and Technology (NIST) webbook. The numerical model was developed based on the assumptions of steady, turbulent and Newtonian flow. For mesh independence test and model validation, the simulation results were compared with published experimental results. The effect of four different performance parameter ranges namely inlet pressure (5 to 8 MPa), inlet temperature (120 to 150 K), heat flux (2 to 5 MW/m2) and mass flux (7000 to 15000 kg/m2s) on heat transfer and flow performances were investigated. It was found that the simulation results showed good agreement with experimental data with maximum deviation of 10 % which indicates the validity of the developed model. At low inlet temperature, the change of specific heat capacity at near-wall region along the tube length was not significant while the pressure drop registered was high. However, significant variation was observed for the case of higher inlet temperature. It was also observed that the heat transfer performance and pressure drop penalty increased when the mass flux was increased. Regarding the effect of inlet pressure, the heat transfer performance and pressure drop results decreased when the inlet pressure is increased.

Ultrasonic atomization of liquids in drop-chain acoustic fountains

PubMed Central

Simon, Julianna C.; Sapozhnikov, Oleg A.; Khokhlova, Vera A.; Crum, Lawrence A.; Bailey, Michael R.

2015-01-01

When focused ultrasound waves of moderate intensity in liquid encounter an air interface, a chain of drops emerges from the liquid surface to form what is known as a drop-chain fountain. Atomization, or the emission of micro-droplets, occurs when the acoustic intensity exceeds a liquid-dependent threshold. While the cavitation-wave hypothesis, which states that atomization arises from a combination of capillary-wave instabilities and cavitation bubble oscillations, is currently the most accepted theory of atomization, more data on the roles of cavitation, capillary waves, and even heat deposition or boiling would be valuable. In this paper, we experimentally test whether bubbles are a significant mechanism of atomization in drop-chain fountains. High-speed photography was used to observe the formation and atomization of drop-chain fountains composed of water and other liquids. For a range of ultrasonic frequencies and liquid sound speeds, it was found that the drop diameters approximately equalled the ultrasonic wavelengths. When water was exchanged for other liquids, it was observed that the atomization threshold increased with shear viscosity. Upon heating water, it was found that the time to commence atomization decreased with increasing temperature. Finally, water was atomized in an overpressure chamber where it was found that atomization was significantly diminished when the static pressure was increased. These results indicate that bubbles, generated by either acoustic cavitation or boiling, contribute significantly to atomization in the drop-chain fountain. PMID:25977591

Investigation of nitrate salts for solar latent heat storage

NASA Astrophysics Data System (ADS)

Kamimoto, M.; Tanaka, T.; Tani, T.; Horigome, T.

1980-01-01

The properties of heat transfer in the discharging of a model solar latent heat storage unit based on various nitrate salts and salt mixtures are investigated. A shell-and-tube-type passive heat exchanger containing NaNO3 or eutectic or off-eutectic mixtures of NaNO3 with KNO3 and Ca(NO3)2 was heated to 40 K above the melting temperature of the salt, when air was made to flow through a heat transfer tube at a constant flow rate, and heat transfer material and air temperatures were monitored. Thermal conductivity and the apparent heat transfer coefficient are estimated from the heat extraction rate and temperature profiles, and it is found that although the thermal conductivities of the materials are similar, the off-eutectic salts exhibit higher heat transfer coefficients. Temperature distributions in the NaNO3-KNO3 mixtures are found to be in fairly good agreement with those predicted by numerical solutions of a one-dimensional finite difference equation, and with approximate analytical solutions. It is observed that the temperature of the heat transfer surface drops rapidly after the appearance of a solid phase, due to the low thermal conductivity of the salts, and means of avoiding this temperature drop are considered.

A neutron spectrometer based on temperature variations in superheated drop compositions

NASA Astrophysics Data System (ADS)

Apfel, Robert E.; d'Errico, Francesco

2002-01-01

The response of superheated drop detectors (SDDs) to neutron radiation varies in a self-consistent manner with variations in temperature and pressure, making such compositions suitable for neutron spectrometry. The advantage of this approach is that the response functions of candidate materials versus energy as the temperature or pressure is varied are nested and have distinct thresholds, with no thermal neutron response. These characteristics permit unfolding without the uncertainties associated with other spectrometry techniques, where multiple solutions are possible, thus requiring an initial guess of the spectrum. A spectrometer was developed based on the well-established technology for acoustic sensing of bubble events interfaced with a proportional-integral-derivative temperature controller. The active monitor for neutrons, called REMbrandt™, was used as the platform for controlling temperature on a SDD probe and for data acquisition, thereby automating the process of measuring the neutron energy spectrum. The new instrument, called REM-SPEC™, implements and automates the original BINS approach: it adjusts the temperature of the SDD vial in increasing steps and measures the bubble event rate at each step. By using two distinct SDD materials with overlapping responses, the 0.1-20 MeV range of energies relevant to practical spectrometry is readily covered. Initial experiments with an Am-Be source validate the operational protocols of this device.

The survivability of Bacillus anthracis (Sterne strain) in processed liquid eggs.

PubMed

Khan, Saeed A; Sung, Kidon; Nawaz, Mohamed S; Cerniglia, Carl E; Tamplin, Mark L; Phillips, Robert W; Kelley, Lynda Collins

2009-04-01

In this study, we investigated the survival and inactivation kinetics of a surrogate strain of Bacillus anthracis (Sterne strain) in whole egg (WE), egg white (EW), sugared egg yolk (YSU), and salted egg yolk (YSA) at low (-20, 0, and 5 degrees C), moderate (15, 20, 25, 30, 35, and 40 degrees C), and high storage temperatures (45, 50, 55, and 60 degrees C). Outgrowth of the spores was measured as lag phase duration (LPD). Replication of vegetative cells was measured in terms of growth rate (GR) and maximum population density (MPD). Spore inactivation was recorded as inactivation rate and percent reduction in viable count. In general, spore viability decreased at low and high temperatures and increased at moderate temperatures. At 0 and 5 degrees C, a 60-100% reduction in spore viability was seen within 2-3 weeks in WE and YSU, 0-30% in YSA, and 50-100% in EW. At -20 degrees C, however, no drop in spore titer was observed in YSU and EW but a 20% drop in titer was seen in YSA and 50% in WE within 2-3 weeks. At high temperatures, WE, EW, and YSA produced a 20-50% drop in the spore titer within 1-4h whereas YSU showed 100% inactivation within 0.75 h. At moderate storage temperatures, as the temperature increased from 15 to 40 degrees C, LPD decreased from 13.5 to 0.75 h and MPD reached 0.27-2.2 x1 0(9) CFU/ml in YSU and WE, respectively. Markedly lower growth was observed in YSA (LPD=24-270 h, MPD=9 x 10(5) CFU/ml) and spores were inactivated completely within 1-6h in EW. The survivability and inactivation data of B. anthracis in liquid egg products reported in this investigation will be helpful in developing risk assessment models on food biosecurity.

Retrotransposons as regulators of gene expression.

PubMed

Elbarbary, Reyad A; Lucas, Bronwyn A; Maquat, Lynne E

2016-02-12

Transposable elements (TEs) are both a boon and a bane to eukaryotic organisms, depending on where they integrate into the genome and how their sequences function once integrated. We focus on two types of TEs: long interspersed elements (LINEs) and short interspersed elements (SINEs). LINEs and SINEs are retrotransposons; that is, they transpose via an RNA intermediate. We discuss how LINEs and SINEs have expanded in eukaryotic genomes and contribute to genome evolution. An emerging body of evidence indicates that LINEs and SINEs function to regulate gene expression by affecting chromatin structure, gene transcription, pre-mRNA processing, or aspects of mRNA metabolism. We also describe how adenosine-to-inosine editing influences SINE function and how ongoing retrotransposition is countered by the body's defense mechanisms. Copyright © 2016, American Association for the Advancement of Science.

A reconfigurable continuous-flow fluidic routing fabric using a modular, scalable primitive.

PubMed

Silva, Ryan; Bhatia, Swapnil; Densmore, Douglas

2016-07-05

Microfluidic devices, by definition, are required to move liquids from one physical location to another. Given a finite and frequently fixed set of physical channels to route fluids, a primitive design element that allows reconfigurable routing of that fluid from any of n input ports to any n output ports will dramatically change the paradigms by which these chips are designed and applied. Furthermore, if these elements are "regular" regarding their design, the programming and fabrication of these elements becomes scalable. This paper presents such a design element called a transposer. We illustrate the design, fabrication and operation of a single transposer. We then scale this design to create a programmable fabric towards a general-purpose, reconfigurable microfluidic platform analogous to the Field Programmable Gate Array (FPGA) found in digital electronics.

Initial investigations into preschoolers' mirror-style versus transposed bodily imitation.

PubMed

Dunphy-Lelii, Sarah

2014-03-01

In typical development, imitation plays a key role in sociocognitive competence. The current study investigated a hypothesised developmental trajectory in face-to-face full body imitation style in 91 preschoolers, as well as a relation between imitation style and theory of mind (ToM). Children's response style to 8 lateralized action prompts was recorded as either "mirror" or "transposed." Overall, mirror-style response increased with age, and was predominant for children and an adult comparison group. Imitation style varied depending on the prompt given, with certain actions showing a side bias regardless of prompt viewed. Mirror-style response was correlated with ToM performance after controlling for language ability, but not after controlling for age. Findings are discussed regarding the hypothesised relation between postural synchrony and larger perspective-taking competence.

Investigation of the Mid-Atlantic coast sudden cold water

NASA Astrophysics Data System (ADS)

Sun, D.; Kafatos, M.; Liu, Z.; Chiu, L.

2003-12-01

In the midsummer of this year, it was reported that there was a tremendous change in ocean temperature along the Mid-Atlantic coast, dropping as much as 10 degrees overnight. This sudden sea surface temperature drop affected local tourism and fishing, keep the tourists out of water at this vacation time, caused local tuna fishing hasn't been as good this year, but the cold water lured chill-loving striped bass close to shore, and has two to three weeks of great rockfish, which fishermen could normally get till fall. This article investigates this event by using satellite observations, numerical model outputs, and surface weather analysis. It is found that the North Atlantic cold current, combined with the coastal upwelling driven by the weather influence might cause this sudden cold SST event.

[Temperature measurement of DC argon plasma jet].

PubMed

Yan, Jian-Hua; Pan, Xin-Chao; Ma, Zeng-Yi; Tu, Xin; Cen, Ke-Fa

2008-01-01

The electron temperature of DC arc plasma jet is an important parameter, which determines the characteristics of plasma jet. The measurement of emission spectrum was performed to obtain the spectral intensities of some Ar lines and the method of diagrammatic view of Boltzmann was adopted to calculate the electron temperature. The results indicated that the electron temperature dropped at different speed along with the axes of the plasma jet and rose rapidly when the current was increased, and it also rose when the flowrate of argon was increased.

Fuel thermal stability effects on spray characteristics

NASA Technical Reports Server (NTRS)

Lefebvre, A. H.; Nickolaus, D.

1987-01-01

The propensity of a heated hydrocarbon fuel toward solids deposition within a fuel injector is investigated experimentally. Fuel is arranged to flow through the injector at constant temperature, pressure, and flow rate and the pressure drop across the nozzle is monitored to provide an indication of the amount of deposition. After deposits have formed, the nozzle is removed from the test rig and its spray performance is compared with its performance before deposition. The spray characteristics measured include mean drop size, drop-size distribution, and radial and circumferential fuel distribution. It is found that small amounts of deposition can produce severe distortion of the fuel spray pattern. More extensive deposition restores spray uniformity, but the nozzle flow rate is seriously curtailed.

Circadian Rhythm of Wrist Temperature among Shift Workers in South Korea: A Prospective Observational Study

PubMed Central

Kim, Hyunjoo; Kang, Suk-Hoon; Choo, Sang-Hyo; Lee, In-Seok; Choi, Kyung-Hwa

2017-01-01

Background: Human body temperature varies with circadian rhythm. To determine the effect of shift work on the circadian rhythm of the distal-skin temperature, wrist temperatures were measured. Methods: Wrist-skin temperatures were measured by an iButton® Temperature Logger. It was measured every 3 min for two and eight consecutive working days in the day and shift workers, respectively. Mesor, amplitude, and acrophase were measured by Cosinor analysis. Results: The shift-worker amplitude dropped significantly as the night shift progressed (0.92 to 0.85 °C), dropped further during rest (0.69 °C), and rose during the morning-shift days (0.82 °C). Day workers still had higher amplitudes (0.93 °C) than the morning-shift workers. The acrophase was delayed during the four night-shift days, then advanced during rest days and the morning-shift days. Nevertheless, the morning-shift worker acrophase was still significantly delayed compared to the day workers (08:03 a.m. vs. 04:11 a.m.). Conclusions: The further reduction of wrist-temperature amplitude during rest after the night shift may be due to the signal circadian rhythm disruption. Reduced amplitudes have been reported to be associated with intolerance to shift work. The findings of our study may help to design the most desirable schedule for shift workers. PMID:28946653

Circadian Rhythm of Wrist Temperature among Shift Workers in South Korea: A Prospective Observational Study.

PubMed

Jang, Tae-Won; Kim, Hyunjoo; Kang, Suk-Hoon; Choo, Sang-Hyo; Lee, In-Seok; Choi, Kyung-Hwa

2017-09-24

Background : Human body temperature varies with circadian rhythm. To determine the effect of shift work on the circadian rhythm of the distal-skin temperature, wrist temperatures were measured. Methods : Wrist-skin temperatures were measured by an iButton ® Temperature Logger. It was measured every 3 min for two and eight consecutive working days in the day and shift workers, respectively. Mesor, amplitude, and acrophase were measured by Cosinor analysis. Results : The shift-worker amplitude dropped significantly as the night shift progressed (0.92 to 0.85 °C), dropped further during rest (0.69 °C), and rose during the morning-shift days (0.82 °C). Day workers still had higher amplitudes (0.93 °C) than the morning-shift workers. The acrophase was delayed during the four night-shift days, then advanced during rest days and the morning-shift days. Nevertheless, the morning-shift worker acrophase was still significantly delayed compared to the day workers (08:03 a.m. vs. 04:11 a.m.). Conclusions : The further reduction of wrist-temperature amplitude during rest after the night shift may be due to the signal circadian rhythm disruption. Reduced amplitudes have been reported to be associated with intolerance to shift work. The findings of our study may help to design the most desirable schedule for shift workers.

The Evolution of the Stratopause During the 2006 Major Warming: Satellite Data and Assimilated Meteorological Analyses

NASA Technical Reports Server (NTRS)

Manney, Gloria L.; Krueger, Kirstin; Pawson, Steven; Schwartz, Michael J.; Daffer, William H.; Livesey, Nathaniel J.; Remsberg, Ellis E.; Mlynczak, Martin G.; Russell, James M., III; Waters, Joe W.

2007-01-01

Microwave Limb Sounder and Sounding of the Atmosphere with Broadband Emission Radiometry data show the polar stratopause, usually higher than and separated from that at midlatitudes, dropping from <55-60 to near 30 km, and cooling dramatically in January 2006 during a major stratospheric sudden warming (SSW). After a nearly isothermal period, a cool stratopause reforms near 75 km in early February, then drops to <55 km and warms. The stratopause is separated in longitude as well as latitude, with lowest temperatures in the transition regions between higher and lower stratopauses. Operational assimilated meteorological analyses, which are not constrained by data at stratopause altitude, do not capture a secondary temperature maximum that overlies the stratopause or the very high stratopause that reforms after the SSW; they underestimate the stratopause altitude variation during the SSW. High-quality daily satellite temperature measurements are invaluable in improving our understanding of stratopause evolution and its representation in models and assimilation systems.

Characterization of Virgin Olive Oils with Two Kinds of 'Frostbitten Olives' Sensory Defect.

PubMed

Romero, Inmaculada; Aparicio-Ruiz, Ramón; Oliver-Pozo, Celia; Aparicio, Ramón; García-González, Diego L

2016-07-13

The frost of olives on the tree due to drops of temperature can produce sensory defects in virgin olive oil (VOO). Temperature changes can be abrupt with freeze-thaw cycles or gradual, and they produce sensory and chemical variations in the oil. This study has analyzed the quality parameters (free fatty acids, peroxide value, UV absorption, and fatty acid ethyl esters) and phenols of VOOs described with the 'frostbitten olives' sensory defect. The phenol profiles allowed grouping these VOOs into two types. One of them, characterized with "soapy" and "strawberry-like" aroma descriptors, had higher values of 1-acetoxypinoresinol, pinoresinol, and aldehydic form of the ligstroside aglycon. The other one, characterized with "wood" and "humidity" descriptors, had higher concentrations of luteolin and apigenin. Most VOOs (75%) from the first group, associated with abrupt drops of temperature, have concentration of phenols higher than the value established by the health claim on olive oil polyphenols approved by the European Commission.

Calorimetric determination of the heat of combustion of spent Green River shale at 978 K

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

Mraw, S.C.; Keweshan, C.F.

1987-08-01

A Calvet-type calorimeter was used to measure heats of combustion of spent Colorado oil shales. For Green River shale, the samples were members of a sink-float series spanning oil yields from 87 to 340 L . tonne/sup -1/. Shale samples (30-200 mg) are dropped into the calorimeter at high temperature, and a peak in the thermopile signal records the total enthalpy change of the sample between room temperature and the final temperature. Duplicate samples from the above sink-float series were first retorted at 773 K and then dropped separately into nitrogen and oxygen at 978 K. The resulting heats aremore » subtracted to give the heat of combustion, and the results are compared to values from classical bomb calorimetry. The agreement shows that the heats of combustion of the organic component are well understood but that question remain on the reactions of the mineral components.« less

Effect of combined platinum and electron on the temperature dependence of forward voltage in fast recovery diode

NASA Astrophysics Data System (ADS)

Jia, Yun-Peng; Zhao, Bao; Yang, Fei; Wu, Yu; Zhou, Xuan; Li, Zhe; Tan, Jian

2015-12-01

The temperature dependences of forward voltage drop (VF) of the fast recovery diodes (FRDs) are remarkably influenced by different lifetime controlled treatments. In this paper the results of an experimental study are presented, which are the lifetime controls of platinum treatment, electron irradiation treatment, and the combined treatment of the above ones. Based on deep level transient spectroscopy (DLTS) measurements, a new level E6 (EC-0.376 eV) is found in the combined lifetime treated (CLT) sample, which is different from the levels of the individual platinum and electron irradiation ones. Comparing the tested VF results of CLT samples with the others, the level E6 is responsible for the degradation of temperature dependence of the forward voltage drop in the FRD. Project supported by the Doctoral Fund of Ministry of Education of China (Grant No. 20111103120016) and the State Grid Corporation of China Program of Science and Technology, China (Grant No. 5455DW140003).

Experimental investigation of a reticulated porous alumina heat exchanger for high temperature gas heat recovery

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

Banerjee, A; Chandran, RB; Davidson, JH

2015-01-22

The present study presents an experimental study of a prototype counter-flow heat exchanger designed to recover sensible heat from inert and reactive gases flowing through a high temperature solar reactor for splitting CO2. The tube-in-tube heat exchanger is comprised of two concentric alumina tubes, each filled with reticulated porous alumina with a nominal porosity of 80% and pore density of 5 pores per inch (ppi). The RPC provides high heat transfer surface area per unit volume (917 m(-1)) with low pressure drop. Measurements include the permeability, inertial coefficient, overall heat transfer coefficient, effectiveness and pressure drop. For laminar flow andmore » an inlet gas temperature of 1240 K, the overall heat transfer coefficients are 36-41 W m(-2) K-1. The measured performance is in good agreement with a prior CFD model of the heat exchanger. (C) 2014 Elsevier Ltd. All rights reserved.« less

Eye temperature and heart rate variability of calves disbudded with or without local anaesthetic.

PubMed

Stewart, M; Stafford, K J; Dowling, S K; Schaefer, A L; Webster, J R

2008-03-18

The possibility that pain can be detected from changes in eye temperature and heart rate variability (HRV) during disbudding was examined in thirty calves, randomly assigned to four treatments: 1) sham handling (control), 2) local anaesthetic (LA, cornual nerve injection) and sham disbudded, 3) sham LA and disbudded, 4) LA and disbudded. During a 40 min sampling period, maximum eye temperature, behavior and HRV parameters were recorded continuously. One week later, twelve disbudded calves were injected with adrenocorticotrophic hormone (ACTH) or saline and maximum eye temperature was recorded. There was a rapid drop in eye temperature during the 5 min following disbudding without LA (P<0.05). Eye temperature then increased and was higher than baseline over the remaining sampling period following both disbudding procedures (P<0.001), a response which could not be explained by increased physical activity LA increased eye temperature prior to disbudding (P<0.001). Heart rate increased (P<0.001) during the 5 min following disbudding with and without LA, however, LF/HF ratio only increased during this time (P<0.01) following disbudding without LA. Eye temperature did not change following ACTH, suggesting that hypothalamus-pituitary-adrenal axis (HPA) activity is not responsible for the changes in eye temperature following disbudding. The increase in LF/HF ratio following disbudding without LA suggests an acute sympathetic response to pain, which could be responsible for the drop in eye temperature via vasoconstriction. HRV and eye temperature together may be a useful non-invasive and more immediate index of pain than HPA activity alone.

Corneal surface temperature change as the mode of stimulation of the non-contact corneal aesthesiometer.

PubMed

Murphy, P J; Morgan, P B; Patel, S; Marshall, J

1999-05-01

The non-contact corneal aesthesiometer (NCCA) assesses corneal sensitivity by using a controlled pulse of air, directed at the corneal surface. The purpose of this paper was to investigate whether corneal surface temperature change was a component in the mode of stimulation. Thermocouple experiment: A simple model corneal surface was developed that was composed of a moistened circle of filter paper placed on a thermocouple and mounted on a glass slide. The temperature change produced by different stimulus pressures was measured for five different ambient temperatures. Thermal camera experiment: Using a thermal camera, the corneal surface temperature change was measured in nine young, healthy subjects after exposure to different stimulus air pulses. Pulse duration was set at 0.9 s but was varied in pressure from 0.5 to 3.5 millibars. Thermocouple experiment: An immediate drop in temperature was detected by the thermocouple as soon as the air flow was incident on the filter paper. A greater temperature change was produced by increasing the pressure of the incident air flow. A relationship was found and a calibration curve plotted. Thermal camera experiment: For each subject, a drop in surface temperature was detected at each stimulus pressure. Furthermore, as the stimulus pressure increased, the induced reduction in temperature also increased. A relationship was found and a calibration curve plotted. The NCCA air-pulse stimulus was capable of producing a localized temperature change on the corneal surface. The principal mode of corneal nerve stimulation, by the NCCA air pulse, was the rate of temperature change of the corneal surface.

Rapid determination of caffeine in one drop of beverages and foods using drop-to-drop solvent microextraction with gas chromatography/mass spectrometry.

PubMed

Shrivas, Kamlesh; Wu, Hui-Fen

2007-11-02

A simple and rapid sample cleanup and preconcentration method for the quantitative determination of caffeine in one drop of beverages and foods by gas chromatography/mass spectrometry (GC/MS) has been proposed using drop-to-drop solvent microextraction (DDSME). The best optimum experimental conditions for DDSME were: chloroform as the extraction solvent, 5 min extraction time, 0.5 microL exposure volume of the extraction phase and no salt addition at room temperature. The optimized methodology exhibited good linearity between 0.05 and 5.0 microg/mL with correlation coefficient of 0.980. The relative standard deviation (RSD) and limits of detection (LOD) of the DDSME/GC/MS method were 4.4% and 4.0 ng/mL, respectively. Relative recovery of caffeine in beverages and foods were found to be 96.6-101%, which showing good reliability of this method. This DDSME excludes the major disadvantages of conventional method of caffeine extraction, like large amount of organic solvent and sample consumption and long sample pre-treatment process. So, this approach proves that the DDSME/GC/MS technique can be applied as a simple, fast and feasible diagnosis tool for environmental, food and biological application for extremely small amount of real sample analysis.

Compact genome of the Antarctic midge is likely an adaptation to an extreme environment.

PubMed

Kelley, Joanna L; Peyton, Justin T; Fiston-Lavier, Anna-Sophie; Teets, Nicholas M; Yee, Muh-Ching; Johnston, J Spencer; Bustamante, Carlos D; Lee, Richard E; Denlinger, David L

2014-08-12

The midge, Belgica antarctica, is the only insect endemic to Antarctica, and thus it offers a powerful model for probing responses to extreme temperatures, freeze tolerance, dehydration, osmotic stress, ultraviolet radiation and other forms of environmental stress. Here we present the first genome assembly of an extremophile, the first dipteran in the family Chironomidae, and the first Antarctic eukaryote to be sequenced. At 99 megabases, B. antarctica has the smallest insect genome sequenced thus far. Although it has a similar number of genes as other Diptera, the midge genome has very low repeat density and a reduction in intron length. Environmental extremes appear to constrain genome architecture, not gene content. The few transposable elements present are mainly ancient, inactive retroelements. An abundance of genes associated with development, regulation of metabolism and responses to external stimuli may reflect adaptations for surviving in this harsh environment.

Compact genome of the Antarctic midge is likely an adaptation to an extreme environment

PubMed Central

Kelley, Joanna L.; Peyton, Justin T.; Fiston-Lavier, Anna-Sophie; Teets, Nicholas M.; Yee, Muh-Ching; Johnston, J. Spencer; Bustamante, Carlos D.; Lee, Richard E.; Denlinger, David L.

2014-01-01

The midge, Belgica antarctica, is the only insect endemic to Antarctica, and thus it offers a powerful model for probing responses to extreme temperatures, freeze tolerance, dehydration, osmotic stress, ultraviolet radiation and other forms of environmental stress. Here we present the first genome assembly of an extremophile, the first dipteran in the family Chironomidae, and the first Antarctic eukaryote to be sequenced. At 99 megabases, B. antarctica has the smallest insect genome sequenced thus far. Although it has a similar number of genes as other Diptera, the midge genome has very low repeat density and a reduction in intron length. Environmental extremes appear to constrain genome architecture, not gene content. The few transposable elements present are mainly ancient, inactive retroelements. An abundance of genes associated with development, regulation of metabolism and responses to external stimuli may reflect adaptations for surviving in this harsh environment. PMID:25118180

Entanglement negativity bounds for fermionic Gaussian states

NASA Astrophysics Data System (ADS)

Eisert, Jens; Eisler, Viktor; Zimborás, Zoltán

2018-04-01

The entanglement negativity is a versatile measure of entanglement that has numerous applications in quantum information and in condensed matter theory. It can not only efficiently be computed in the Hilbert space dimension, but for noninteracting bosonic systems, one can compute the negativity efficiently in the number of modes. However, such an efficient computation does not carry over to the fermionic realm, the ultimate reason for this being that the partial transpose of a fermionic Gaussian state is no longer Gaussian. To provide a remedy for this state of affairs, in this work, we introduce efficiently computable and rigorous upper and lower bounds to the negativity, making use of techniques of semidefinite programming, building upon the Lagrangian formulation of fermionic linear optics, and exploiting suitable products of Gaussian operators. We discuss examples in quantum many-body theory and hint at applications in the study of topological properties at finite temperature.

Laminar flow studies of a low-temperature space radiator model using D-shaped tubes

NASA Technical Reports Server (NTRS)

Cintula, T. C.; Prok, G. M.; Johnston, D. B.

1972-01-01

Test results of a low-temperature space radiator model are presented. Radiator performance is evaluated with a low-thermal-conductivity fluid in laminar flow in D-shaped cross-section tubes. The test covered a Reynolds number range from 50 to 4500 and a fluid temperature range from 294 to 414 K (70 to 286 F). For low-temperature radiators, the fluid-to-surface temperature differential was predominately influenced by fluid temperature in laminar flow. Heat transfer and pressure drop for the radiator tube could be predicted within engineering accuracy from existing correlations.

Seasonal Ice Zone Reconnaissance Surveys Coordination

DTIC Science & Technology

2016-03-30

sea surface temperature (SST), sea level atmospheric pressure ( SLP ), and velocity (Steele), and dropsonde measurements of atmospheric properties...aircraft), cloud top/base heights UpTempO buoys for understanding and prediction…. Steele UpTempO buoy drops for SLP , SST, SSS, & surface velocity...reflectance, skin temperature, visible imagery AXCTD= Air Expendable CTD, AXCP= Air Expendable Current Profiler, SLP = Sea Level atmospheric

A Fresh Look at the Semiconductor Bandgap Using Constant Current Data

ERIC Educational Resources Information Center

Ocaya, R. O.; Luhanga, P. V. C.

2011-01-01

It is shown that the well-known linear variation of p-n diode terminal voltage with temperature at different fixed forward currents allows easy and accurate determination of the semiconductor ideality factor and bandgap from only two data points. This is possible if the temperature difference required to maintain the same diode voltage drop can be…

Ultraviolet Rayleigh Scatter Imaging for Spatial Temperature Profiles in Atmospheric Microdischarges

DTIC Science & Technology

2014-09-01

regime and not in a neighboring regime such as an abnormal glow or a corona discharge . As discussed in section 3.1, unlike abnormal discharges or... coronas , normal glows have a voltage drop that is independent of discharge current for several orders of magnitude, which would manifest itself...5 3.2 Discharge Power and Gas Temperature

Effects of Simulated Heat Waves with Strong Sudden Cooling Weather on ApoE Knockout Mice

PubMed Central

Zhang, Shuyu; Kuang, Zhengzhong; Zhang, Xiakun

2015-01-01

This study analyzes the mechanism of influence of heat waves with strong sudden cooling on cardiovascular diseases (CVD) in ApoE−/− mice. The process of heat waves with strong sudden cooling was simulated with a TEM1880 meteorological-environment simulation chamber according to the data obtained at 5 a.m. of 19 June 2006 to 11 p.m. of 22 June 2006. Forty-eight ApoE−/− mice were divided into six blocks based on their weight. Two mice from each block were randomly assigned to control, heat wave, temperature drop, and rewarming temperature groups. The experimental groups were transferred into the climate simulator chamber for exposure to the simulated heat wave process with strong sudden temperature drop. After 55, 59, and 75 h of exposure, the experimental groups were successively removed from the chamber to monitor physiological indicators. Blood samples were collected by decollation, and the hearts were harvested in all groups. The levels of heat stress factors (HSP60, SOD, TNF, sICAM-1, HIF-1α), cold stress factors (NE, EPI), vasoconstrictor factors (ANGII, ET-1, NO), and four items of blood lipid (TC, TG, HDL-C, and LDL-C) were measured in each ApoE−/− mouse. Results showed that the heat waves increased the levels of heat stress factors except SOD decreased, and decreased the levels of vasoconstrictor factors and blood lipid factors except TC increased. The strong sudden temperature drop in the heat wave process increased the levels of cold stress factors, vasoconstrictor factors and four blood lipid items (except the level of HDL-C which decreased) and decreased the levels of heat stress factors (except the level of SOD which increased). The analysis showed that heat waves could enhance atherosclerosis of ApoE−/− mice. The strong sudden temperature drop during the heat wave process increased the plasma concentrations of NE and ANGII, which indicates SNS activation, and resulted in increased blood pressure. NE and ANGII are vasoconstrictors involved in systemic vasoconstriction especially in the superficial areas of the body and conducive to increased blood pressure. The increase in the blood lipid levels of TG, LDL-C, TC, and LDL-C/HDL-C further aggravated CVD. This paper explored the influence mechanism of the heat waves with sudden cooling on CVD in ApoE−/− mice. PMID:26016434

Effects of Simulated Heat Waves with Strong Sudden Cooling Weather on ApoE Knockout Mice.

PubMed

Zhang, Shuyu; Kuang, Zhengzhong; Zhang, Xiakun

2015-05-26

This study analyzes the mechanism of influence of heat waves with strong sudden cooling on cardiovascular diseases (CVD) in ApoE-/- mice. The process of heat waves with strong sudden cooling was simulated with a TEM1880 meteorological-environment simulation chamber according to the data obtained at 5 a.m. of 19 June 2006 to 11 p.m. of 22 June 2006. Forty-eight ApoE-/- mice were divided into six blocks based on their weight. Two mice from each block were randomly assigned to control, heat wave, temperature drop, and rewarming temperature groups. The experimental groups were transferred into the climate simulator chamber for exposure to the simulated heat wave process with strong sudden temperature drop. After 55, 59, and 75 h of exposure, the experimental groups were successively removed from the chamber to monitor physiological indicators. Blood samples were collected by decollation, and the hearts were harvested in all groups. The levels of heat stress factors (HSP60, SOD, TNF, sICAM-1, HIF-1α), cold stress factors (NE, EPI), vasoconstrictor factors (ANGII, ET-1, NO), and four items of blood lipid (TC, TG, HDL-C, and LDL-C) were measured in each ApoE-/- mouse. Results showed that the heat waves increased the levels of heat stress factors except SOD decreased, and decreased the levels of vasoconstrictor factors and blood lipid factors except TC increased. The strong sudden temperature drop in the heat wave process increased the levels of cold stress factors, vasoconstrictor factors and four blood lipid items (except the level of HDL-C which decreased) and decreased the levels of heat stress factors (except the level of SOD which increased). The analysis showed that heat waves could enhance atherosclerosis of ApoE-/- mice. The strong sudden temperature drop during the heat wave process increased the plasma concentrations of NE and ANGII, which indicates SNS activation, and resulted in increased blood pressure. NE and ANGII are vasoconstrictors involved in systemic vasoconstriction especially in the superficial areas of the body and conducive to increased blood pressure. The increase in the blood lipid levels of TG, LDL-C, TC, and LDL-C/HDL-C further aggravated CVD. This paper explored the influence mechanism of the heat waves with sudden cooling on CVD in ApoE-/- mice.

Transposition of the great arteries

MedlinePlus

... that carry blood away from the heart -- the aorta and the pulmonary artery -- are switched (transposed). ... side of the heart and travels out the aorta to the body. In TGA, venous blood returns ...

Annual Technical Report, Materials Research Laboratory, 1 July 1982 - 30 June 1983.

DTIC Science & Technology

1983-06-30

array of 10 determine the gnajlerial properties to strain rates infra-red radiation detectors , each of which measures greater than 10 s’. temperature...linear array of detectors which will allow us a closer num a drop in temperature raises the flow stress, look at the temperature profile, especially...Hartley, M.S. example, experimental evidence for quantum-me- Thesis, June, 1983. chanical tunneling effects on the viscoelastic relaxa- tion in poly

Mariner transposons are sailing in the genome of the blood-sucking bug Rhodnius prolixus.

PubMed

Filée, Jonathan; Rouault, Jacques-Deric; Harry, Myriam; Hua-Van, Aurélie

2015-12-15

The Triatomine bug Rhodnius prolixus is a vector of Trypanosoma cruzi, which causes the Chagas disease in Latin America. R. prolixus can also transfer transposable elements horizontally across a wide range of species. We have taken advantage of the availability of the 700 Mbp complete genome sequence of R. prolixus to study the dynamics of invasion and persistence of transposable elements in this species. Using both library-based and de novo methods of transposon detection, we found less than 6 % of transposable elements in the R. prolixus genome, a relatively low percentage compared to other insect genomes with a similar genome size. DNA transposons are surprisingly abundant and elements belonging to the mariner family are by far the most preponderant components of the mobile part of this genome with 11,015 mariner transposons that could be clustered in 89 groups (75 % of the mobilome). Our analysis allowed the detection of a new mariner clade in the R. prolixus genome, that we called nosferatis. We demonstrated that a large diversity of mariner elements invaded the genome and expanded successfully over time via three main processes. (i) several families experienced recent and massive expansion, for example an explosive burst of a single mariner family led to the generation of more than 8000 copies. These recent expansion events explain the unusual prevalence of mariner transposons in the R. prolixus genome. Other families expanded via older bursts of transposition demonstrating the long lasting permissibility of mariner transposons in the R. prolixus genome. (ii) Many non-autonomous families generated by internal deletions were also identified. Interestingly, two non autonomous families were generated by atypical recombinations (5' part replacement with 3' part). (iii) at least 10 cases of horizontal transfers were found, supporting the idea that host/vector relationships played a pivotal role in the transmission and subsequent persistence of transposable elements in this genome. These data provide a new insight into the evolution of transposons in the genomes of hematophagous insects and bring additional evidences that lateral exchanges of mobile genetics elements occur frequently in the R. prolixus genome.

The effect of the impactor diameter and temperature on low velocity impact behavior of CFRP laminates

NASA Astrophysics Data System (ADS)

Evci, C.; Uyandıran, I.

2017-02-01

Impact damage is one of the major concerns that should be taken into account with the new aircraft and spacecraft structures which employ ever-growing use of composite materials. Considering the thermal loads encountered at different altitudes, both low and high temperatures can affect the properties and impact behavior of composite materials. This study aims to investigate the effect of temperature and impactor diameter on the impact behavior and damage development in balanced and symmetrical CFRP laminates which were manufactured by employing vacuum bagging process with autoclave cure. Instrumented drop-weight impact testing system is used to perform the low velocity impact tests in a range of temperatures ranged from 60 down to -50 °C. Impact tests for each temperature level were conducted using three different hemispherical impactor diameters varying from 10 to 20 mm. Energy profile method is employed to determine the impact threshold energies for damage evolution. The level of impact damage is determined from the dent depth on the impacted face and delamination damage detected using ultrasonic C-Scan technique. Test results reveal that the threshold of penetration energy, main failure force and delamination area increase with impactor diameter at all temperature levels. No clear influence of temperature on the critical force thresholds could be derived. However, penetration threshold energy decreased as the temperature was lowered. Drop in the penetration threshold was more obvious with quite low temperatures. Delamination damage area increased while the temperature decreased from +60 °C to -50 °C.

Integrating temperature with odor processing in the olfactory bulb.

PubMed

Kludt, Eugen; Okom, Camille; Brinkmann, Alexander; Schild, Detlev

2015-05-20

Temperature perception has long been classified as a somesthetic function solely. However, in recent years several studies brought evidence that temperature perception also takes place in the olfactory system of rodents. Temperature has been described as an effective stimulus for sensory neurons of the Grueneberg ganglion located at the entrance of the nose. Here, we investigate whether a neuronal trace of temperature stimulation can be observed in the glomeruli and mitral cells of the olfactory bulb, using calcium imaging and fast line-scanning microscopy. We show in the Xenopus tadpole system that the γ-glomerulus, which receives input from olfactory neurons, is highly sensitive to temperature drops at the olfactory epithelium. We observed that thermo-induced activity in the γ-glomerulus is conveyed to the mitral cells innervating this specific neuropil. Surprisingly, a substantial number of thermosensitive mitral cells were also chemosensitive. Moreover, we report another unique feature of the γ-glomerulus: it receives ipsilateral and contralateral afferents. The latter fibers pass through the contralateral bulb, cross the anterior commissure, and then run to the ipsilateral olfactory bulb, where they target the γ-glomerulus. Temperature drops at the contralateral olfactory epithelium also induced responses in the γ-glomerulus and in mitral cells. Temperature thus appears to be a relevant physiological input to the Xenopus olfactory system. Each olfactory bulb integrates and codes temperature signals originating from receptor neurons of the ipsilateral and contralateral nasal cavities. Finally, temperature and chemical information is processed in shared cellular networks. Copyright © 2015 the authors 0270-6474/15/357892-11$15.00/0.

Metastable phase formation in undercooled Fe-Co melts under terrestrial and parabolic flight conditions

NASA Astrophysics Data System (ADS)

Hermann, R.; Löser, W.; Lindenkreuz, H. G.; Yang-Bitterlich, W.; Mickel, Ch.; Diefenbach, A.; Schneider, S.; Dreier, W.

2007-12-01

Soft magnetic Fe-Co alloys display primary fcc phase solidification for>19,5 at% Co in conventional near-equilibrium solidification processes. Undercooled Fe-Co melt drops within the composition range of 30 to 50 at% Co have been investigated with the electromagnetic levitation technique. The solidification kinetics was measured in situ using a high-resolution Siphotodiode. Melt drops were undercooled up to 263 K below the liquidus temperature and subsequently quenched onto a chill substrate in order to characterize the solidification sequence and microstructure. The transition from stable fcc phase to metastable bcc primary phase solidification has been observed after reaching a critical undercooling level. The critical undercooling increases with rising Co content. The growth velocity drops obviously after transition to metastable bcc phase formation. Parabolic flight experiments were performed in order to study the phase selection under reduced gravity conditions. Under microgravity conditions, a much smaller critical undercooling and an increased life time of the metastable bcc phase were obtained. This result was validated with TEM investigations. The appearance of Fe-O particles gives an indirect hint for an intermediate fcc phase formation from the metastable bcc phase at elevated temperature.

Classification of Arctic, Mid-Latitude and Tropical Clouds in the Mixed-Phase Temperature Regime

NASA Astrophysics Data System (ADS)

Costa, Anja; Afchine, Armin; Luebke, Anna; Meyer, Jessica; Dorsey, James R.; Gallagher, Martin W.; Ehrlich, André; Wendisch, Manfred; Krämer, Martina

2016-04-01

The degree of glaciation and the sizes and habits of ice particles formed in mixed-phase clouds remain not fully understood. However, these properties define the mixed clouds' radiative impact on the Earth's climate and thus a correct representation of this cloud type in global climate models is of importance for an improved certainty of climate predictions. This study focuses on the occurrence and characteristics of two types of clouds in the mixed-phase temperature regime (238-275K): coexistence clouds (Coex), in which both liquid drops and ice crystals exist, and fully glaciated clouds that develop in the Wegener-Bergeron-Findeisen regime (WBF clouds). We present an extensive dataset obtained by the Cloud and Aerosol Particle Spectrometer NIXE-CAPS, covering Arctic, mid-latitude and tropical regions. In total, we spent 45.2 hours within clouds in the mixed-phase temperature regime during five field campaigns (Arctic: VERDI, 2012 and RACEPAC, 2014 - Northern Canada; mid-latitude: COALESC, 2011 - UK and ML-Cirrus, 2014 - central Europe; tropics: ACRIDICON, 2014 - Brazil). We show that WBF and Coex clouds can be identified via cloud particle size distributions. The classified datasets are used to analyse temperature dependences of both cloud types as well as range and frequencies of cloud particle concentrations and sizes. One result is that Coex clouds containing supercooled liquid drops are found down to temperatures of -40 deg C only in tropical mixed clouds, while in the Arctic and mid-latitudes no liquid drops are observed below about -20 deg C. In addition, we show that the cloud particles' aspherical fractions - derived from polarization signatures of particles with diameters between 20 and 50 micrometers - differ significantly between WBF and Coex clouds. In Coex clouds, the aspherical fraction of cloud particles is generally very low, but increases with decreasing temperature. In WBF clouds, where all cloud particles are ice, about 20-40% of the cloud particles are nevertheless classified as spherical for all temperatures, possibly indicating columnar ice crystals (see Järvinen et al, submitted to JAS 2016).

Method for controlling protein crystallization

NASA Technical Reports Server (NTRS)

Noever, David A. (Inventor)

1993-01-01

A method and apparatus for controlling the crystallization of protein by solvent evaporation including placing a drop of protein solution between and in contact with a pair of parallel plates and driving one of the plates toward and away from the other plate in a controlled manner to adjust the spacing between the plates is presented. The drop of solution forms a liquid cylinder having a height dependent upon the plate spacing thereby effecting the surface area available for solvent evaporation. When the spacing is close, evaporation is slow. Evaporation is increased by increasing the spacing between the plates until the breaking point of the liquid cylinder. One plate is mounted upon a fixed post while the other plate is carried by a receptacle movable relative to the post and driven by a belt driven screw drive. The temperature and humidity of the drop of protein solution are controlled by sealing the drop within the receptacle and mounting a heater and dessicant within the receptacle.

A systematic search of sudden pressure drops on Gale crater during two Martian years derived from MSL/REMS data

NASA Astrophysics Data System (ADS)

Ordonez-Etxeberria, Iñaki; Hueso, Ricardo; Sánchez-Lavega, Agustín

2018-01-01

The Mars Science Laboratory (MSL) rover carries a suite of meteorological detectors that constitute the Rover Environmental Monitoring Station (REMS) instrument. REMS investigates the meteorological conditions at Gale crater by obtaining high-frequency data of pressure, air and ground temperature, relative humidity, UV flux at the surface and wind intensity and direction with some limitations in the wind data. We have run a search of atmospheric pressure drops of short duration (< 25 s) and we present a statistical study of the frequency of these events in the REMS pressure data during its first 1417 sols (more than two Martian years). The identified daytime pressure drops could be caused by the close passages of warm vortices and dust devils. Previous systematic searches of warm vortices from REMS pressure data (Kahanpää et al., 2016; Steakley and Murphy, 2016) cover about one Martian year. We show that sudden pressure drops are twice more abundant in the second Martian year [sols 671-1339] than in the first one analyzed in previous works. The higher number of detections could be linked to a combination of different topography, higher altitudes (120 m above the landing site) and true inter-annual meteorological variability. We found 1129 events with a pressure drop larger than 0.5 Pa. Of these, 635 occurred during the local daytime (∼56%) and 494 were nocturnal. The most intense pressure drop (4.2 Pa) occurred at daytime on sol 1417 (areocentric solar longitude Ls = 195°) and was accompanied by a simultaneous decrease in the UV signal of 7.1%, pointing to a true dust devil. We also discuss similar but less intense simultaneous pressure and UV radiation drops that constitute 0.7% of all daytime events. Most of the intense daytime pressure drops with variations larger than 1.0 Pa occur when the difference between air and ground temperature is larger than 15 K. Statistically, the frequency of daytime pressure drops peaks close to noon (12:00-13:00 Local True Solar Time or LTST) with more events in spring and summer (Ls from 180° to 360°). The nocturnal sudden pressure drops concentrate in the 20:00-23:00 LTST time interval and they only occur in spring and summer. We interpret these nocturnal events as a consequence of local mechanically forced turbulence. This interpretation is consistent with published results from simulations with the MRAMS model (Rafkin et al., 2016) that predict a competition between local orographic circulation and global Hadley cell circulation at Gale crater at summer night-time that can enhance forced turbulence at the surface. Bursts of pressure drops appear on particular sols, especially at night-time. Most of the vortex bursts occurred when MSL was in the region called Pahrump Hills characterized by a complex terrain. A comparison of the daytime pressure drops from REMS data with published results from the Pathfinder and Phoenix missions shows that the frequency of daytime events at Gale crater in spring and summer is similar to the one previously found at other locations. Finally, we present possible correlations between MSL activity and some daytime pressure drops. If such an instrumental effect is present in the REMS data its impact in this analysis is small and would only affect about 7% of our detections.

[Impact of low temperature in young ear formation stage on rice seed setting.

PubMed

Ma, Shu Qing; Liu, Xiao Hang; Deng, Kui Cai; Quan, Hu Jie; Tong, Li Yuan; Xi, Zhu Xiang; Chai, Qing Rong; Yang, Jun

2018-01-01

A low temperature treatment in rice booting key period was executed on the north slope of Changbai Mountains to construct the impact model of low temperature on rice shell rate, and to reveal the effects of low temperature at different stages of rice young panicle on seed setting. The results showed that effects of low temperature in the young ear formation stage on rice shell rate generally followed the logarithmic function, the lower the temperature was, the greater the temperature influence coefficient was, and the longer the low temperature duration was, the higher rice shell rate was. The seed setting rate was most sensitive to low temperature in the middle time of booting stage (the period from formation to meiosis of the pollen mother cell), followed by the early and later stages. During the booting stage, with 1 ℃ decrease of daily temperature under 2-, 3- and 5-day low temperature treatments, the shell rate increased by 0.5, 1.7 and 4.3 percentage, respectively, and with 1 ℃ decrease of daily minimum temperature, the shell rate increased by 0.4,1.8 and 4.5 percentage, respectively. The impact of 2-day low temperature was smaller than that of 3 days or more. The impact of accumulative cold-temperature on the shell rate followed exponential function. In the range of harmful low temperature, rice shell rate increased about 8.5 percentage with the accumulative cold-temperature increasing 10 ℃·d. When the 3 days average temperature dropped to 21.6, 18.0 and 15.0 ℃, or the 5 days average temperature dropped to 22.0, 20.4 and 18.5 ℃, or the accumulative cold-temperature was more than 8, 19, 26 ℃·d, the light, moderate and severe booting stage chilling injury would occur, respectively. In Northeast China, low temperature within 2 d in rice booting stage might not cause moderate and severe chilling injury.

The impact of transposable elements on mammalian development

PubMed Central

Garcia-Perez, Jose L.; Widmann, Thomas J.; Adams, Ian R.

2018-01-01

Summary Despite often being classified as selfish or junk DNA, transposable elements (TEs) are a group of abundant genetic sequences that significantly impact on mammalian development and genome regulation. In recent years, our understanding of how pre-existing TEs affect genome architecture, gene regulatory networks and protein function during mammalian embryogenesis has dramatically expanded. In addition, the mobilization of active TEs in selected cell types has been shown to generate genetic variation during development and in fully differentiated tissues. Importantly, the ongoing domestication and evolution of TEs appears to provide a rich source of regulatory elements, functional modules and genetic variation that fuels the evolution of mammalian developmental processes. Here, we review the functional impact that TEs exert on mammalian developmental processes and how the somatic activity of TEs can influence gene regulatory networks. PMID:27875251

Evolution and genome architecture in fungal plant pathogens.

PubMed

Möller, Mareike; Stukenbrock, Eva H

2017-12-01

The fungal kingdom comprises some of the most devastating plant pathogens. Sequencing the genomes of fungal pathogens has shown a remarkable variability in genome size and architecture. Population genomic data enable us to understand the mechanisms and the history of changes in genome size and adaptive evolution in plant pathogens. Although transposable elements predominantly have negative effects on their host, fungal pathogens provide prominent examples of advantageous associations between rapidly evolving transposable elements and virulence genes that cause variation in virulence phenotypes. By providing homogeneous environments at large regional scales, managed ecosystems, such as modern agriculture, can be conducive for the rapid evolution and dispersal of pathogens. In this Review, we summarize key examples from fungal plant pathogen genomics and discuss evolutionary processes in pathogenic fungi in the context of molecular evolution, population genomics and agriculture.

Hydroelectric System Response to Part Load Vortex Rope Excitation

NASA Astrophysics Data System (ADS)

Alligné, S.; Nicolet, C.; Bégum, A.; Landry, C.; Gomes, J.; Avellan, F.

2016-11-01

The prediction of pressure and output power fluctuations amplitudes on Francis turbine prototype is a challenge for hydro-equipment industry since it is subjected to guarantees to ensure smooth and reliable operation of the hydro units. The European FP7 research project Hyperbole aims to setup a methodology to transpose the pressure fluctuations induced by the cavitation vortex rope on the reduced scale model to the prototype generating units. A Francis turbine unit of 444MW with a specific speed value of v = 0.29, is considered as case study. A SIMSEN model of the power station including electrical system, controllers, rotating train and hydraulic system with transposed draft tube excitation sources is setup. Based on this model, a frequency analysis of the hydroelectric system is performed to analyse potential interactions between hydraulic excitation sources and electrical components.

Bigfoot. a new family of MITE elements characterized from the Medicago genus.

PubMed

Charrier, B; Foucher, F; Kondorosi, E; d'Aubenton-Carafa, Y; Thermes, C; Kondorosi, A; Ratet, P

1999-05-01

We have characterized from the legume plant Medicago a new family of miniature inverted-repeat transposable elements (MITE), called the Bigfoot transposable elements. Two of these insertion elements are present only in a single allele of two different M. sativa genes. Using a PCR strategy we have isolated 19 other Bigfoot elements from the M. sativa and M. truncatula genomes. They differ from the previously characterized MITEs by their sequence, a target site of 9 bp and a partially clustered genomic distribution. In addition, we show that they exhibit a significantly stable secondary structure. These elements may represent up to 0.1% of the genome of the outcrossing Medicago sativa but are present at a reduced copy number in the genome of the autogamous M. truncatula plant, revealing major differences in the genome organization of these two plants.

Solving the corner-turning problem for large interferometers

NASA Astrophysics Data System (ADS)

Lutomirski, Andrew; Tegmark, Max; Sanchez, Nevada J.; Stein, Leo C.; Urry, W. Lynn; Zaldarriaga, Matias

2011-01-01

The so-called corner-turning problem is a major bottleneck for radio telescopes with large numbers of antennas. The problem is essentially that of rapidly transposing a matrix that is too large to store on one single device; in radio interferometry, it occurs because data from each antenna need to be routed to an array of processors each of which will handle a limited portion of the data (say, a frequency range) but requires input from each antenna. We present a low-cost solution allowing the correlator to transpose its data in real time, without contending for bandwidth, via a butterfly network requiring neither additional RAM memory nor expensive general-purpose switching hardware. We discuss possible implementations of this using FPGA, CMOS, analog logic and optical technology, and conclude that the corner-turner cost can be small even for upcoming massive radio arrays.

copia-like retrotransposons are ubiquitous among plants.

PubMed Central

Voytas, D F; Cummings, M P; Koniczny, A; Ausubel, F M; Rodermel, S R

1992-01-01

Transposable genetic elements are assumed to be a feature of all eukaryotic genomes. Their identification, however, has largely been haphazard, limited principally to organisms subjected to molecular or genetic scrutiny. We assessed the phylogenetic distribution of copia-like retrotransposons, a class of transposable element that proliferates by reverse transcription, using a polymerase chain reaction assay designed to detect copia-like element reverse transcriptase sequences. copia-like retrotransposons were identified in 64 plant species as well as the photosynthetic protist Volvox carteri. The plant species included representatives from 9 of 10 plant divisions, including bryophytes, lycopods, ferns, gymnosperms, and angiosperms. DNA sequence analysis of 29 cloned PCR products and of a maize retrotransposon cDNA confirmed the identity of these sequences as copia-like reverse transcriptase sequences, thereby demonstrating that this class of retrotransposons is a ubiquitous component of plant genomes. Images PMID:1379734

Multipartite Entanglement classes via Negativity Fonts

NASA Astrophysics Data System (ADS)

Sharma, Santosh Shelly; Sharma, Naresh Kumar

2012-02-01

The number and types of K-way negativity fonts in canonical form of an N-qubit state depends on the nature and amount of quantum coherences in the state. Non zero determinants of negativity fonts, characterizing a given state, are easily written down and reflect the entanglement microstructure of the superposition. A classification criterion for multipartite entangled states, based on negativity fonts in canonical state and decomposition of global partial transpose in terms of K-way partially transposed operators, is proposed. Inequivalent sub-classes are labelled by N-qubit local unitary invariants. A complete classification of four qubit states is obtained. The number of major families for N>3 is found to be 2^N-2N. Classification of four qubit states indicates that a small number of relevant polynomial invariants is enough to classify N-qubit states.

Transposable element islands facilitate adaptation to novel environments in an invasive species

PubMed Central

Schrader, Lukas; Kim, Jay W.; Ence, Daniel; Zimin, Aleksey; Klein, Antonia; Wyschetzki, Katharina; Weichselgartner, Tobias; Kemena, Carsten; Stökl, Johannes; Schultner, Eva; Wurm, Yannick; Smith, Christopher D.; Yandell, Mark; Heinze, Jürgen; Gadau, Jürgen; Oettler, Jan

2014-01-01

Adaptation requires genetic variation, but founder populations are generally genetically depleted. Here we sequence two populations of an inbred ant that diverge in phenotype to determine how variability is generated. Cardiocondyla obscurior has the smallest of the sequenced ant genomes and its structure suggests a fundamental role of transposable elements (TEs) in adaptive evolution. Accumulations of TEs (TE islands) comprising 7.18% of the genome evolve faster than other regions with regard to single-nucleotide variants, gene/exon duplications and deletions and gene homology. A non-random distribution of gene families, larvae/adult specific gene expression and signs of differential methylation in TE islands indicate intragenomic differences in regulation, evolutionary rates and coalescent effective population size. Our study reveals a tripartite interplay between TEs, life history and adaptation in an invasive species. PMID:25510865

Identification of structural variation in mouse genomes.

PubMed

Keane, Thomas M; Wong, Kim; Adams, David J; Flint, Jonathan; Reymond, Alexandre; Yalcin, Binnaz

2014-01-01

Structural variation is variation in structure of DNA regions affecting DNA sequence length and/or orientation. It generally includes deletions, insertions, copy-number gains, inversions, and transposable elements. Traditionally, the identification of structural variation in genomes has been challenging. However, with the recent advances in high-throughput DNA sequencing and paired-end mapping (PEM) methods, the ability to identify structural variation and their respective association to human diseases has improved considerably. In this review, we describe our current knowledge of structural variation in the mouse, one of the prime model systems for studying human diseases and mammalian biology. We further present the evolutionary implications of structural variation on transposable elements. We conclude with future directions on the study of structural variation in mouse genomes that will increase our understanding of molecular architecture and functional consequences of structural variation.

The transposability of the Mediterranean-type diet in non-Mediterranean regions: application to the physician/allied health team.

PubMed

Speed, C

2004-12-01

Studies are consistently declaring that the Mediterranean-type diet is transposable to non-Mediterranean regions. The nutritional end points of Med-type eating appear to be achievable through foods from a variety of traditions and appear to support predetermined expectations surrounding food preparation, choice, taste and sensory appeal. The broad emphasis on minimally processed plants and their products (vegetables, fruit, legumes, wholegrains, nuts, seeds and oils); low fat dairy, fish, less emphasis on animal products and removal of partially hydrogenated fats has piqued the attention of health professionals who are interested in arresting the incidence of chronic disease. The theoretical underpinnings of Med-type eating have driven new understandings in dietary guidelines, which is especially timely as well-marketed fad diets loom large on the current health horizon.

Short interspersed transposable elements (SINEs) are excluded from imprinted regions in the human genome.

PubMed

Greally, John M

2002-01-08

To test whether regions undergoing genomic imprinting have unique genomic characteristics, imprinted and nonimprinted human loci were compared for nucleotide and retroelement composition. Maternally and paternally expressed subgroups of imprinted genes were found to differ in terms of guanine and cytosine, CpG, and retroelement content, indicating a segregation into distinct genomic compartments. Imprinted regions have been normally permissive to L1 long interspersed transposable element retroposition during mammalian evolution but universally and significantly lack short interspersed transposable elements (SINEs). The primate-specific Alu SINEs, as well as the more ancient mammalian-wide interspersed repeat SINEs, are found at significantly low densities in imprinted regions. The latter paleogenomic signature indicates that the sequence characteristics of currently imprinted regions existed before the mammalian radiation. Transitions from imprinted to nonimprinted genomic regions in cis are characterized by a sharp inflection in SINE content, demonstrating that this genomic characteristic can help predict the presence and extent of regions undergoing imprinting. During primate evolution, SINE accumulation in imprinted regions occurred at a decreased rate compared with control loci. The constraint on SINE accumulation in imprinted regions may be mediated by an active selection process. This selection could be because of SINEs attracting and spreading methylation, as has been found at other loci. Methylation-induced silencing could lead to deleterious consequences at imprinted loci, where inactivation of one allele is already established, and expression is often essential for embryonic growth and survival.

Short interspersed transposable elements (SINEs) are excluded from imprinted regions in the human genome

PubMed Central

Greally, John M.

2002-01-01

To test whether regions undergoing genomic imprinting have unique genomic characteristics, imprinted and nonimprinted human loci were compared for nucleotide and retroelement composition. Maternally and paternally expressed subgroups of imprinted genes were found to differ in terms of guanine and cytosine, CpG, and retroelement content, indicating a segregation into distinct genomic compartments. Imprinted regions have been normally permissive to L1 long interspersed transposable element retroposition during mammalian evolution but universally and significantly lack short interspersed transposable elements (SINEs). The primate-specific Alu SINEs, as well as the more ancient mammalian-wide interspersed repeat SINEs, are found at significantly low densities in imprinted regions. The latter paleogenomic signature indicates that the sequence characteristics of currently imprinted regions existed before the mammalian radiation. Transitions from imprinted to nonimprinted genomic regions in cis are characterized by a sharp inflection in SINE content, demonstrating that this genomic characteristic can help predict the presence and extent of regions undergoing imprinting. During primate evolution, SINE accumulation in imprinted regions occurred at a decreased rate compared with control loci. The constraint on SINE accumulation in imprinted regions may be mediated by an active selection process. This selection could be because of SINEs attracting and spreading methylation, as has been found at other loci. Methylation-induced silencing could lead to deleterious consequences at imprinted loci, where inactivation of one allele is already established, and expression is often essential for embryonic growth and survival. PMID:11756672

Transposable Elements versus the Fungal Genome: Impact on Whole-Genome Architecture and Transcriptional Profiles

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

Castanera, Raul; Lopez-Varas, Leticia; Borgognone, Alessandra

Transposable elements (TEs) are exceptional contributors to eukaryotic genome diversity. Their ubiquitous presence impacts the genomes of nearly all species and mediates genome evolution by causing mutations and chromosomal rearrangements and by modulating gene expression. We performed an exhaustive analysis of the TE content in 18 fungal genomes, including strains of the same species and species of the same genera. Our results depicted a scenario of exceptional variability, with species having 0.02 to 29.8% of their genome consisting of transposable elements. A detailed analysis performed on two strains of Pleurotus ostreatus uncovered a genome that is populated mainly by Classmore » I elements, especially LTR-retrotransposons amplified in recent bursts from 0 to 2 million years (My) ago. The preferential accumulation of TEs in clusters led to the presence of genomic regions that lacked intra- and inter-specific conservation. In addition, we investigated the effect of TE insertions on the expression of their nearby upstream and downstream genes. Our results showed that an important number of genes under TE influence are significantly repressed, with stronger repression when genes are localized within transposon clusters. Our transcriptional analysis performed in four additional fungal models revealed that this TE-mediated silencing was present only in species with active cytosine methylation machinery. We hypothesize that this phenomenon is related to epigenetic defense mechanisms that are aimed to suppress TE expression and control their proliferation.« less

The Evolution of Tyrosine-Recombinase Elements in Nematoda

PubMed Central

Szitenberg, Amir; Koutsovoulos, Georgios; Blaxter, Mark L.; Lunt, David H.

2014-01-01

Transposable elements can be categorised into DNA and RNA elements based on their mechanism of transposition. Tyrosine recombinase elements (YREs) are relatively rare and poorly understood, despite sharing characteristics with both DNA and RNA elements. Previously, the Nematoda have been reported to have a substantially different diversity of YREs compared to other animal phyla: the Dirs1-like YRE retrotransposon was encountered in most animal phyla but not in Nematoda, and a unique Pat1-like YRE retrotransposon has only been recorded from Nematoda. We explored the diversity of YREs in Nematoda by sampling broadly across the phylum and including 34 genomes representing the three classes within Nematoda. We developed a method to isolate and classify YREs based on both feature organization and phylogenetic relationships in an open and reproducible workflow. We also ensured that our phylogenetic approach to YRE classification identified truncated and degenerate elements, informatively increasing the number of elements sampled. We identified Dirs1-like elements (thought to be absent from Nematoda) in the nematode classes Enoplia and Dorylaimia indicating that nematode model species do not adequately represent the diversity of transposable elements in the phylum. Nematode Pat1-like elements were found to be a derived form of another Pat1-like element that is present more widely in animals. Several sequence features used widely for the classification of YREs were found to be homoplasious, highlighting the need for a phylogenetically-based classification scheme. Nematode model species do not represent the diversity of transposable elements in the phylum. PMID:25197791

Transposable Elements versus the Fungal Genome: Impact on Whole-Genome Architecture and Transcriptional Profiles

DOE PAGES

Castanera, Raul; Lopez-Varas, Leticia; Borgognone, Alessandra; ...

2016-06-13

Transposable elements (TEs) are exceptional contributors to eukaryotic genome diversity. Their ubiquitous presence impacts the genomes of nearly all species and mediates genome evolution by causing mutations and chromosomal rearrangements and by modulating gene expression. We performed an exhaustive analysis of the TE content in 18 fungal genomes, including strains of the same species and species of the same genera. Our results depicted a scenario of exceptional variability, with species having 0.02 to 29.8% of their genome consisting of transposable elements. A detailed analysis performed on two strains of Pleurotus ostreatus uncovered a genome that is populated mainly by Classmore » I elements, especially LTR-retrotransposons amplified in recent bursts from 0 to 2 million years (My) ago. The preferential accumulation of TEs in clusters led to the presence of genomic regions that lacked intra- and inter-specific conservation. In addition, we investigated the effect of TE insertions on the expression of their nearby upstream and downstream genes. Our results showed that an important number of genes under TE influence are significantly repressed, with stronger repression when genes are localized within transposon clusters. Our transcriptional analysis performed in four additional fungal models revealed that this TE-mediated silencing was present only in species with active cytosine methylation machinery. We hypothesize that this phenomenon is related to epigenetic defense mechanisms that are aimed to suppress TE expression and control their proliferation.« less

A novel hAT element in Bombyx mori and Rhodnius prolixus: its relationship with miniature inverted repeat transposable elements (MITEs) and horizontal transfer.

PubMed

Zhang, H-H; Shen, Y-H; Xu, H-E; Liang, H-Y; Han, M-J; Zhang, Z

2013-10-01

Comparative analysis of transposable elements (TEs) from different species can make it possible to reconstruct their history over evolutionary time. In this study, we identified a novel hAT element in Bombyx mori and Rhodnius prolixus with characteristic GGGCGGCA repeats in its subterminal region. Meanwhile, phylogenetic analysis demonstrated that the elements in these two species might represent a separate cluster of the hAT superfamily. Strikingly, a previously identified miniature inverted repeat transposable element (MITE) shared high identity with this autonomous element across the entire length, supporting the hypothesis that MITEs are derived from the internal deletion of DNA transposons. Interestingly, identity of the consensus sequences of this novel hAT element between B. mori and R. prolixus, which diverged about 370 million years ago, was as high as 96.5% over their full length (about 3.6 kb) at the nucleotide level. The patchy distribution amongst species, coupled with overall lack of intense purifying selection acting on this element, suggest that this novel hAT element might have experienced horizontal transfer between the ancestors of B. mori and R. prolixus. Our results highlight that this novel hAT element could be used as a potential tool for germline transformation of R. prolixus to control the transmission of Trypanosoma cruzi, which causes Chagas disease. © 2013 Royal Entomological Society.

Flood Frequency Analyses Using a Modified Stochastic Storm Transposition Method

NASA Astrophysics Data System (ADS)

Fang, N. Z.; Kiani, M.

2015-12-01

Research shows that areas with similar topography and climatic environment have comparable precipitation occurrences. Reproduction and realization of historical rainfall events provide foundations for frequency analysis and the advancement of meteorological studies. Stochastic Storm Transposition (SST) is a method for such a purpose and enables us to perform hydrologic frequency analyses by transposing observed historical storm events to the sites of interest. However, many previous studies in SST reveal drawbacks from simplified Probability Density Functions (PDFs) without considering restrictions for transposing rainfalls. The goal of this study is to stochastically examine the impacts of extreme events on all locations in a homogeneity zone. Since storms with the same probability of occurrence on homogenous areas do not have the identical hydrologic impacts, the authors utilize detailed precipitation parameters including the probability of occurrence of certain depth and the number of occurrence of extreme events, which are both incorporated into a joint probability function. The new approach can reduce the bias from uniformly transposing storms which erroneously increases the probability of occurrence of storms in areas with higher rainfall depths. This procedure is iterated to simulate storm events for one thousand years as the basis for updating frequency analysis curves such as IDF and FFA. The study area is the Upper Trinity River watershed including the Dallas-Fort Worth metroplex with a total area of 6,500 mi2. It is the first time that SST method is examined in such a wide scale with 20 years of radar rainfall data.

DPTEdb, an integrative database of transposable elements in dioecious plants.

PubMed

Li, Shu-Fen; Zhang, Guo-Jun; Zhang, Xue-Jin; Yuan, Jin-Hong; Deng, Chuan-Liang; Gu, Lian-Feng; Gao, Wu-Jun

2016-01-01

Dioecious plants usually harbor 'young' sex chromosomes, providing an opportunity to study the early stages of sex chromosome evolution. Transposable elements (TEs) are mobile DNA elements frequently found in plants and are suggested to play important roles in plant sex chromosome evolution. The genomes of several dioecious plants have been sequenced, offering an opportunity to annotate and mine the TE data. However, comprehensive and unified annotation of TEs in these dioecious plants is still lacking. In this study, we constructed a dioecious plant transposable element database (DPTEdb). DPTEdb is a specific, comprehensive and unified relational database and web interface. We used a combination of de novo, structure-based and homology-based approaches to identify TEs from the genome assemblies of previously published data, as well as our own. The database currently integrates eight dioecious plant species and a total of 31 340 TEs along with classification information. DPTEdb provides user-friendly web interfaces to browse, search and download the TE sequences in the database. Users can also use tools, including BLAST, GetORF, HMMER, Cut sequence and JBrowse, to analyze TE data. Given the role of TEs in plant sex chromosome evolution, the database will contribute to the investigation of TEs in structural, functional and evolutionary dynamics of the genome of dioecious plants. In addition, the database will supplement the research of sex diversification and sex chromosome evolution of dioecious plants.Database URL: http://genedenovoweb.ticp.net:81/DPTEdb/index.php. © The Author(s) 2016. Published by Oxford University Press.

The evolution of tyrosine-recombinase elements in Nematoda.

PubMed

Szitenberg, Amir; Koutsovoulos, Georgios; Blaxter, Mark L; Lunt, David H

2014-01-01

Transposable elements can be categorised into DNA and RNA elements based on their mechanism of transposition. Tyrosine recombinase elements (YREs) are relatively rare and poorly understood, despite sharing characteristics with both DNA and RNA elements. Previously, the Nematoda have been reported to have a substantially different diversity of YREs compared to other animal phyla: the Dirs1-like YRE retrotransposon was encountered in most animal phyla but not in Nematoda, and a unique Pat1-like YRE retrotransposon has only been recorded from Nematoda. We explored the diversity of YREs in Nematoda by sampling broadly across the phylum and including 34 genomes representing the three classes within Nematoda. We developed a method to isolate and classify YREs based on both feature organization and phylogenetic relationships in an open and reproducible workflow. We also ensured that our phylogenetic approach to YRE classification identified truncated and degenerate elements, informatively increasing the number of elements sampled. We identified Dirs1-like elements (thought to be absent from Nematoda) in the nematode classes Enoplia and Dorylaimia indicating that nematode model species do not adequately represent the diversity of transposable elements in the phylum. Nematode Pat1-like elements were found to be a derived form of another Pat1-like element that is present more widely in animals. Several sequence features used widely for the classification of YREs were found to be homoplasious, highlighting the need for a phylogenetically-based classification scheme. Nematode model species do not represent the diversity of transposable elements in the phylum.

Deletions in the tetracycline resistance determinant reduce the thermosensitivity of a trfA(Ts) derivative of plasmid RP1 in Pseudomonas aeruginosa.

PubMed

Rella, M; Watson, J M; Thomas, C M; Haas, D

1987-01-01

A derivative of the broad-host-range plasmid RP1, pME301, was temperature-sensitive (Ts) at 43 degrees C for maintenance in Pseudomonas aeruginosa, P. mendocina, Klebsiella aerogenes and Escherichia coli. In E. coli, the Ts defect of pME301 could be complemented in trans by the cloned trfA gene, which is known to be essential for RP1 replication in E. coli and P. aeruginosa. Because pME301 expressed a Ts phenotype in P. mendocina and K. aerogenes, we assume that the trfA function is also vital in these organisms. When plasmid-encoded carbenicillin resistance (on transposon Tn801) was selected at non-permissive temperatures in P. aeruginosa strain PAO carrying pME301, we obtained either Tn801 insertions into the chromosome or pME301 derivatives having a deletion (or point mutation) in their tet genes, which determine resistance to tetracycline and are not transposable. From cloning experiments, we infer that the tet gene product(s) destabilize the pME301 replicon in P. aeruginosa at 40-43 degrees C.

Mechanical reinforcement for RACC cables in high magnetic background fields

NASA Astrophysics Data System (ADS)

Bayer, C. M.; Gade, P. V.; Barth, C.; Preuß, A.; Jung, A.; Weiß, K. P.

2016-02-01

Operable in liquid helium, liquid hydrogen or liquid nitrogen, high temperature superconductor (HTS) cables are investigated as future alternatives to low temperature superconductor (LTS) cables in magnet applications. Different high current HTS cable concepts have been developed and optimized in the last years—each coming with its own benefits and challenges. As the Roebel assembled coated conductor (RACC) is the only fully transposed HTS cable investigated so far, it is attractive for large scale magnet and accelerator magnet applications when field quality and alternating current (AC) losses are of highest importance. However, due to its filamentary character, the RACC is very sensitive to Lorentz forces. In order to increase the mechanical strength of the RACC, each of the HTS strands was covered by an additional copper tape. After investigating the maximum applicable transverse pressure on the strand composition, the cable was clamped into a stainless steel structure to reinforce it against Lorentz forces. A comprehensive test has been carried out in the FBI facility at 4.2 K in a magnetic field of up to 12 T. This publication discusses the maximum applicable pressure as well as the behaviour of the RACC cable as a function of an external magnetic field.

Polysaccharide peptide induces a tumor necrosis factor-α-dependent drop of body temperature in rats.

PubMed

Jedrzejewski, Tomasz; Piotrowski, Jakub; Wrotek, Sylwia; Kozak, Wieslaw

2014-08-01

Polysaccharide peptide (PSP) extracted from the Coriolus versicolor mushroom is frequently suggested as an adjunct to the chemo- or radiotherapy in cancer patients. It improves quality of the patients' life by decreasing pain, fatigue, loss of appetite, nausea, and vomiting. However, the effect of PSP on body temperature has not thus far been studied, although it is well known that treatment with other polysaccharide adjuvants, such as lipopolysaccharides, may induce fever. The aim of the present study, therefore, was to investigate the influence of PSP on temperature regulation in rats. We report that intraperitoneal injection of PSP provoked a dose-dependent decrease of temperature in male Wistar rats equipped with biotelemetry devices to monitor deep body temperature (Tb). The response was rapid (i.e., with latency of 15-20min), transient (lasting up to 5h post-injection), and accompanied by a significant elevation of the blood tumor necrosis factor-α (TNF-α) level. Pretreatment of the rats with anti-TNF-α antibody prevented the PSP-induced drop in Tb. Based on these data, we conclude that rats may develop an anapyrexia-like response to the injection of peptidopolysaccharide rather than fever, and the response was TNF-α-dependent. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermal and electric properties of Nd(1.85)Ce(0.15)CuO(4-y) and Pr(1.85)Ce(0.15)CuO(4-y)

NASA Technical Reports Server (NTRS)

Lim, Z. S.; Han, K. H.; Lee, Sung-Ik; Jeong, Yoon H.; Song, Y. S.; Park, Y. W.

1990-01-01

Electric resistivity, magnetic susceptibility, thermoelectric power, and Hall coefficient of Nd(1.85)Ce(0.15)CuO(4-y) and Pr(1.85)Ce(0.15)CuO(4-y) whose onset temperature of the superconductivity are 24 K and 23 K were measured. Experimental results show many interesting features. In particular, the Hall coefficients are negative and relatively flat as a function of temperature. However, the temperature dependence of the thermoelectric power (TEP) for these two samples shows the positive sign for both samples in contrast to the previous results. Moreover TEP for both samples remains flat in the normal state below 250 K, but decreases rapidly above 250 K. TEP of only Pr(1.85)Ce(0.15)CuO(4-y) shows a peak near 50 K. Finally onset temperatures of sudden drop of TEP are higher than those of resistance drop. The physical properties of these samples produced at different conditions such as different heat treatment temperatures, atmospheres were also measured. TEP and resistance measurement show that oxygen deficiency is essential to produce better superconducting samples. Correlation between TEP and superconductivity for these different samples will be discussed.

Thermal and electric properties of Nd(1.85)Ce(0.15)CuO(4-y) and Pr(1.85)Ce(0.15)CuO(4-y)

NASA Technical Reports Server (NTRS)

Lim, Z. S.; Han, K. H.; Lee, Sung-Ik; Jeong, Yoon H.; Song, Y. S.; Park, Y. W.

1991-01-01

Electric resistivity, magnetic susceptibility, thermoelectric power, and Hall coefficient of Nd(1.85)Ce(0.15)CuO(4-y) and Pr(1.85)Ce(0.15)CuO(4-y) whose onset temperature of the superconductivity are 24 and 23 K were measured. Experimental results show many interesting features. In particular, the Hall coefficients are negative and relatively flat as a function of temperature. However, the temperature dependence of the thermoelectric power (TEP) for these two samples shows the positive sign for both samples in contrast to the previous results. Moreover, TEP for both samples remains flat in the normal state below 250 K, but decreases rapidly above 250 K. TEP of only Pr(1.85)Ce(0.15)CuO(4-y) shows a peak near 50 K. Finally, onset temperatures of sudden drop of TEP are higher than those of resistance drop. The physical properties of these samples produced at different conditions such as different heat treatment temperatures, atmospheres were also measured. TEP and resistance measurement show that oxygen deficiency is essential to produce better superconducting samples. Correlation between TEP and superconductivity for these different samples are discussed.

Alternate-Fueled Combustor-Sector Performance

NASA Technical Reports Server (NTRS)

Thomas, Anna E.; Saxena, Nikita T.; Shouse, Dale T.; Neuroth, Craig; Hendricks, Robert C.; Lynch, Amy; Frayne, Charles W.; Stutrud, Jeffrey S.; Corporan, Edwin; Hankins, Terry

2013-01-01

In order to realize alternative fueling for military and commercial use, the industry has set forth guidelines that must be met by each fuel. These aviation fueling requirements are outlined in MIL-DTL-83133F(2008) or ASTM D 7566 Annex (2011) standards, and are classified as "drop-in" fuel replacements. This report provides combustor performance data for synthetic-paraffinic-kerosene- (SPK-) type (Fischer-Tropsch (FT)) fuel and blends with JP-8+100, relative to JP-8+100 as baseline fueling. Data were taken at various nominal inlet conditions: 75 psia (0.52 MPa) at 500 degF (533 K), 125 psia (0.86 MPa) at 625 degF (603 K), 175 psia (1.21 MPa) at 725 degF (658 K), and 225 psia (1.55 MPa) at 790 degF (694 K). Combustor performance analysis assessments were made for the change in flame temperatures, combustor efficiency, wall temperatures, and exhaust plane temperatures at 3, 4, and 5 percent combustor pressure drop (DP) for fuel:air ratios (F/A) ranging from 0.010 to 0.025. Significant general trends show lower liner temperatures and higher flame and combustor outlet temperatures with increases in FT fueling relative to JP-8+100 fueling. The latter affects both turbine efficiency and blade and vane lives.

Performance of a multiple venturi fuel-air preparation system. [fuel injection for gas turbines

NASA Technical Reports Server (NTRS)

Tacina, R. R.

1979-01-01

Spatial fuel-air distributions, degree of vaporization, and pressure drop were measured 16.5 cm downstream of the fuel injection plane of a multiple Venturi tube fuel injector. Tests were performed in a 12 cm tubular duct. Test conditions were: a pressure of 0.3 MPa, inlet air temperature from 400 to 800K, air velocities of 10 and 20 m/s, and fuel-air ratios of 0.010 and 0.020. The fuel was Diesel #2. Spatial fuel-air distributions were within + or - 20 percent of the mean at inlet air temperatures above 450K. At an inlet air temperature of 400K, the fuel-air distribution was measured when a 50 percent blockage plate was placed 9.2 cm upstream of the fuel injection plane to distort the inlet air velocity fuel injection plane to distort the inlet air velocity profile. Vaporization of the fuel was 50 percent complete at an inlet air temperature of 400K and the percentage increased linearly with temperature to complete vaporization at 600K. The pressure drop was 3 percent at the design point which was three times greater than the designed value and the single tube experiment value. No autoignition or flashback was observed at the conditions tested.

A bi-directional two-phase/two-phase heat exchanger

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura

1993-01-01

This paper describes the design and test of a heat exchanger that transfers heat from one two-phase thermal loop to another with very small drops in temperature and pressure. The heat exchanger condenses the vapor in one loop while evaporating the liquid in the other without mixing of the condensing and evaporating fluids. The heat exchanger is bidirectional in that it can transfer heat in reverse, condensing on the normally evaporating side and vice versa. It is fully compatible with capillary pumped loops and mechanically pumped loops. Test results verified that performance of the heat exchanger met the design requirements. It demonstrated a heat transfer rate of 6800 watts in the normal mode of operation and 1000 watts in the reverse mode with temperature drops of less than 5 C between two thermal loops.

Noncontact surface tension and viscosity measurements of molten oxides with a pressurized hybrid electrostatic-aerodynamic levitator

NASA Astrophysics Data System (ADS)

Ishikawa, Takehiko; Yu, Jianding; Paradis, Paul-François

2006-05-01

In order to measure the surface tension and the viscosity of molten oxides, the oscillation drop technique has been applied on a pressurized hybrid electrostatic-aerodynamic levitator. To suppress the electrical discharge between the top and bottom electrodes, the drop excitation method which has been used with high vacuum electrostatic levitators has been modified. As a demonstration, the surface tension and viscosity of liquid BaTiO3 were measured using this new method. Over the 1500-2000K interval, the surface tension was measured as γ(T )=349-0.03 (T-Tm) (10-3N/m), where Tm=1893K is the melting temperature. Similarly, the viscosity was determined as η(T )=0.53exp[5.35×104/(RT)](10-3Pas) over the same temperature interval.

Measurements of the magnetic-field-tuned conductivity of disordered two-dimensional Mo43Ge57 and InOx superconducting films: evidence for a universal minimum superfluid response.

PubMed

Misra, S; Urban, L; Kim, M; Sambandamurthy, G; Yazdani, A

2013-01-18

Our measurements of the low frequency ac conductivity in strongly disordered two-dimensional films near the magnetic-field-tuned superconductor-to-insulator transition show a sudden drop in the phase stiffness of superconducting order with either increased temperature or magnetic field. Surprisingly, for two different material systems, the abrupt drop in the superfluid density in a magnetic field has the same universal value as that expected for a Berezinskii-Kosterlitz-Thouless transition in a zero magnetic field. The characteristic temperature at which phase stiffness is suddenly lost can be tuned to zero at a critical magnetic field, following a power-law behavior with a critical exponent consistent with that obtained in previous dc transport studies on the dissipative side of the transition.