Barley (Hordeum vulgare) circadian clock genes can respond rapidly to temperature in an EARLY FLOWERING 3-dependent manner

PubMed Central

Ford, Brett; Deng, Weiwei; Clausen, Jenni; Oliver, Sandra; Boden, Scott; Hemming, Megan; Trevaskis, Ben

2016-01-01

An increase in global temperatures will impact future crop yields. In the cereal crops wheat and barley, high temperatures accelerate reproductive development, reducing the number of grains per plant and final grain yield. Despite this relationship between temperature and cereal yield, it is not clear what genes and molecular pathways mediate the developmental response to increased temperatures. The plant circadian clock can respond to changes in temperature and is important for photoperiod-dependent flowering, and so is a potential mechanism controlling temperature responses in cereal crops. This study examines the relationship between temperature, the circadian clock, and the expression of flowering-time genes in barley (Hordeum vulgare), a crop model for temperate cereals. Transcript levels of barley core circadian clock genes were assayed over a range of temperatures. Transcript levels of core clock genes CCA1, GI, PRR59, PRR73, PRR95, and LUX are increased at higher temperatures. CCA1 and PRR73 respond rapidly to a decrease in temperature whereas GI and PRR59 respond rapidly to an increase in temperature. The response of GI and the PRR genes to changes in temperature is lost in the elf3 mutant indicating that their response to temperature may be dependent on a functional ELF3 gene. PMID:27580625

Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study.

PubMed

Palacios, C; Abecia, J A

2015-05-01

A total number of 48,088 artificial inseminations (AIs) have been controlled during seven consecutive years in 79 dairy sheep Spanish farms (41° N). Mean, maximum and minimum ambient temperatures (Ts), temperature amplitude (TA), mean relative humidity (RH), mean solar radiation (SR) and total rainfall of each insemination day and 15 days later were recorded. Temperature-humidity index (THI) and effective temperature (ET) have been calculated. A binary logistic regression model to estimate the risk of not getting pregnant compared to getting pregnant, through the odds ratio (OR), was performed. Successful winter inseminations were carried out under higher SR (P < 0.01) and summer inseminations under lower SR values (P < 0.05). Successful inseminations during the summer were performed under significantly lower maximum T (P < 0.01), while winter inseminations resulted in pregnancy when they were carried out under higher maximum (P < 0.05) and minimum Ts (P < 0.01). Up to five meteorological variables presented OR >1 (maximum T, ET and rainfall on AI day, and ET and rainfall on day 15), and two variables presented OR <1 (SR on AI day and maximum T on day 15). However, the effect of meteorological factors affected fertility in opposite ways, so T becomes a protective or risk factor on fertility depending on season. In conclusion, the percentage of pregnancy after AI in sheep is significantly affected by meteorological variables in a seasonal-dependent manner, so the parameters such as temperature reverse their effects in the hot or cold seasons. A forecast of the meteorological conditions could be a useful tool when AI dates are being scheduled.

Meteorological variables affect fertility rate after intrauterine artificial insemination in sheep in a seasonal-dependent manner: a 7-year study

NASA Astrophysics Data System (ADS)

Palacios, C.; Abecia, J. A.

2015-05-01

A total number of 48,088 artificial inseminations (AIs) have been controlled during seven consecutive years in 79 dairy sheep Spanish farms (41° N). Mean, maximum and minimum ambient temperatures ( Ts), temperature amplitude (TA), mean relative humidity (RH), mean solar radiation (SR) and total rainfall of each insemination day and 15 days later were recorded. Temperature-humidity index (THI) and effective temperature (ET) have been calculated. A binary logistic regression model to estimate the risk of not getting pregnant compared to getting pregnant, through the odds ratio (OR), was performed. Successful winter inseminations were carried out under higher SR ( P < 0.01) and summer inseminations under lower SR values ( P < 0.05). Successful inseminations during the summer were performed under significantly lower maximum T ( P < 0.01), while winter inseminations resulted in pregnancy when they were carried out under higher maximum ( P < 0.05) and minimum Ts ( P < 0.01). Up to five meteorological variables presented OR >1 (maximum T, ET and rainfall on AI day, and ET and rainfall on day 15), and two variables presented OR <1 (SR on AI day and maximum T on day 15). However, the effect of meteorological factors affected fertility in opposite ways, so T becomes a protective or risk factor on fertility depending on season. In conclusion, the percentage of pregnancy after AI in sheep is significantly affected by meteorological variables in a seasonal-dependent manner, so the parameters such as temperature reverse their effects in the hot or cold seasons. A forecast of the meteorological conditions could be a useful tool when AI dates are being scheduled.

Factors affecting infection of corals and larval oysters by Vibrio coralliilyticus.

PubMed

Ushijima, Blake; Richards, Gary P; Watson, Michael A; Schubiger, Carla B; Häse, Claudia C

2018-01-01

The bacterium Vibrio coralliilyticus can threaten vital reef ecosystems by causing disease in a variety of coral genera, and, for some strains, increases in virulence at elevated water temperatures. In addition, strains of V. coralliilyticus (formally identified as V. tubiashii) have been implicated in mass mortalities of shellfish larvae causing significant economic losses to the shellfish industry. Recently, strain BAA-450, a coral pathogen, was demonstrated to be virulent towards larval Pacific oysters (Crassostrea gigas). However, it is unclear whether other coral-associated V. coralliilyticus strains can cause shellfish mortalities and if infections are influenced by temperature. This study compared dose dependence, temperature impact, and gross pathology of four V. coralliilyticus strains (BAA-450, OCN008, OCN014 and RE98) on larval C. gigas raised at 23°C and 27°C, and evaluated whether select virulence factors are required for shellfish infections as they are for corals. All strains were infectious to larval oysters in a dose-dependent manner with OCN014 being the most pathogenic and BAA-450 being the least. At 27°C, higher larval mortalities (p < 0.05) were observed for all V. coralliilyticus strains, ranging from 38.8-93.7%. Gross pathological changes to the velum and cilia occurred in diseased larvae, but there were no distinguishable differences between oysters exposed to different V. coralliilyticus strains or temperatures. Additionally, in OCN008, the predicted transcriptional regulator ToxR and the outer membrane protein OmpU were important for coral and oyster disease, while mannose sensitive hemagglutinin type IV pili were required only for coral infection. This study demonstrated that multiple coral pathogens can infect oyster larvae in a temperature-dependent manner and identified virulence factors required for infection of both hosts.

Evaluation of antipyretic potential of Vernonia cinerea extract in rats.

PubMed

Gupta, Malaya; Mazumder, U K; Manikandan, L; Bhattacharya, S; Haldar, P K; Roy, S

2003-08-01

The methanol extract of the whole plant of Vernonia cinerea (MEVC) was evaluated for its antipyretic potential on normal body temperature and yeast-induced pyrexia in rats. MEVC significantly reduced the normal body temperature at doses of 250 and 500 mg/kg body weight p.o. MEVC also lowered the elevated body temperature in the case of yeast-induced pyrexia in a dose dependent manner. The antipyretic effect of the extract at a dose of 500 mg/kg was identical to that of the standard drug paracetamol. Copyright 2003 John Wiley & Sons, Ltd.

The lesser known challenge of climate change: thermal variance and sex-reversal in vertebrates with temperature-dependent sex determination.

PubMed

Neuwald, Jennifer L; Valenzuela, Nicole

2011-03-23

Climate change is expected to disrupt biological systems. Particularly susceptible are species with temperature-dependent sex determination (TSD), as in many reptiles. While the potentially devastating effect of rising mean temperatures on sex ratios in TSD species is appreciated, the consequences of increased thermal variance predicted to accompany climate change remain obscure. Surprisingly, no study has tested if the effect of thermal variance around high-temperatures (which are particularly relevant given climate change predictions) has the same or opposite effects as around lower temperatures. Here we show that sex ratios of the painted turtle (Chrysemys picta) were reversed as fluctuations increased around low and high unisexual mean-temperatures. Unexpectedly, the developmental and sexual responses around female-producing temperatures were decoupled in a more complex manner than around male-producing values. Our novel observations are not fully explained by existing ecological models of development and sex determination, and provide strong evidence that thermal fluctuations are critical for shaping the biological outcomes of climate change.

Ultrasonic Study of Dislocation Dynamics in Lithium -

NASA Astrophysics Data System (ADS)

Han, Myeong-Deok

1987-09-01

Experimental studies of dislocation dynamics in LiF single crystals, using ultrasonic techniques combined with dynamic loading, were performed to investigate the time evolution of the plastic deformation process under a short stress pulse at room temperature, and the temperature dependence of the dislocation damping mechanism in the temperature range 25 - 300(DEGREES)K. From the former, the time dependence of the ultrasonic attenuation was understood as resulting from dislocation multiplication followed by the evolution of mobile dislocations to immobile ones under large stress. From the latter, the temperature dependence of the ultrasonic attenuation was interpreted as due to the motion of the dislocation loops overcoming the periodic Peierls potential barrier in a manner analogous to the motion of a thermalized sine-Gordon chain under a small stress. The Peierls stress obtained from the experimental results by application of Seeger's relaxation model with exponential dislocation length distribution was 4.26MPa, which is consistent with the lowest stress for the linear relation between the dislocation velocity and stress observed by Flinn and Tinder.

Fermentation Temperature Modulates Phosphatidylethanolamine and Phosphatidylinositol Levels in the Cell Membrane of Saccharomyces cerevisiae

PubMed Central

Henderson, Clark M.; Zeno, Wade F.; Lerno, Larry A.; Longo, Marjorie L.

2013-01-01

During alcoholic fermentation, Saccharomyces cerevisiae is exposed to a host of environmental and physiological stresses. Extremes of fermentation temperature have previously been demonstrated to induce fermentation arrest under growth conditions that would otherwise result in complete sugar utilization at “normal” temperatures and nutrient levels. Fermentations were carried out at 15°C, 25°C, and 35°C in a defined high-sugar medium using three Saccharomyces cerevisiae strains with diverse fermentation characteristics. The lipid composition of these strains was analyzed at two fermentation stages, when ethanol levels were low early in stationary phase and in late stationary phase at high ethanol concentrations. Several lipids exhibited dramatic differences in membrane concentration in a temperature-dependent manner. Principal component analysis (PCA) was used as a tool to elucidate correlations between specific lipid species and fermentation temperature for each yeast strain. Fermentations carried out at 35°C exhibited very high concentrations of several phosphatidylinositol species, whereas at 15°C these yeast strains exhibited higher levels of phosphatidylethanolamine and phosphatidylcholine species with medium-chain fatty acids. Furthermore, membrane concentrations of ergosterol were highest in the yeast strain that experienced stuck fermentations at all three temperatures. Fluorescence anisotropy measurements of yeast cell membrane fluidity during fermentation were carried out using the lipophilic fluorophore diphenylhexatriene. These measurements demonstrate that the changes in the lipid composition of these yeast strains across the range of fermentation temperatures used in this study did not significantly affect cell membrane fluidity. However, the results from this study indicate that fermenting S. cerevisiae modulates its membrane lipid composition in a temperature-dependent manner. PMID:23811519

Brassinosteroid signaling-dependent root responses to prolonged elevated ambient temperature.

PubMed

Martins, Sara; Montiel-Jorda, Alvaro; Cayrel, Anne; Huguet, Stéphanie; Roux, Christine Paysant-Le; Ljung, Karin; Vert, Grégory

2017-08-21

Due to their sessile nature, plants have to cope with and adjust to their fluctuating environment. Temperature elevation stimulates the growth of Arabidopsis aerial parts. This process is mediated by increased biosynthesis of the growth-promoting hormone auxin. How plant roots respond to elevated ambient temperature is however still elusive. Here we present strong evidence that temperature elevation impinges on brassinosteroid hormone signaling to alter root growth. We show that elevated temperature leads to increased root elongation, independently of auxin or factors known to drive temperature-mediated shoot growth. We further demonstrate that brassinosteroid signaling regulates root responses to elevated ambient temperature. Increased growth temperature specifically impacts on the level of the brassinosteroid receptor BRI1 to downregulate brassinosteroid signaling and mediate root elongation. Our results establish that BRI1 integrates temperature and brassinosteroid signaling to regulate root growth upon long-term changes in environmental conditions associated with global warming.Moderate heat stimulates the growth of Arabidopsis shoots in an auxin-dependent manner. Here, Martins et al. show that elevated ambient temperature modifies root growth by reducing the BRI1 brassinosteroid-receptor protein level and downregulating brassinosteroid signaling.

Semi-empirical anzatz for Helmholtz free energy calculation: Thermal properties of silver along shock Hugoniot

NASA Astrophysics Data System (ADS)

Joshi, R. H.; Thakore, B. Y.; Bhatt, N. K.; Vyas, P. R.; Jani, A. R.

2018-02-01

A density functional theory along with electronic contribution is used to compute quasiharmonic total energy for silver, whereas explicit phonon anharmonic contribution is added through perturbative term in temperature. Within the Mie-Grüneisen approach, we propose a consistent computational scheme for calculating various thermophysical properties of a substance, in which the required Grüneisen parameter γth is calculated from the knowledge of binding energy. The present study demonstrates that no separate relation for volume dependence for γth is needed, and complete thermodynamics under simultaneous high-temperature and high-pressure condition can be derived in a consistent manner. We have calculated static and dynamic equation of states and some important thermodynamic properties along the shock Hugoniot. A careful examination of temperature dependence of Grüneisen parameter reveals the importance of temperature-effect on various thermal properties.

Fracture Mechanisms For SiC Fibers And SiC/SiC Composites Under Stress-Rupture Conditions at High Temperatures

NASA Technical Reports Server (NTRS)

DiCarlo, James A.; Yun, Hee Mann; Hurst, Janet B.; Viterna, L. (Technical Monitor)

2002-01-01

The successful application of SiC/SiC ceramic matrix composites as high-temperature structural materials depends strongly on maximizing the fracture or rupture life of the load-bearing fiber and matrix constituents. Using high-temperature data measured under stress-rupture test conditions, this study examines in a mechanistic manner the effects of various intrinsic and extrinsic factors on the creep and fracture behavior of a variety of SiC fiber types. It is shown that although some fiber types fracture during a large primary creep stage, the fiber creep rate just prior to fracture plays a key role in determining fiber rupture time (Monkman-Grant theory). If it is assumed that SiC matrices rupture in a similar manner as fibers with the same microstructures, one can develop simple mechanistic models to analyze and optimize the stress-rupture behavior of SiC/SiC composites for applied stresses that are initially below matrix cracking.

Assessing the Temperature Dependence of Narrow-Band Raman Water Vapor Lidar Measurements: A Practical Approach

NASA Technical Reports Server (NTRS)

Whiteman, David N.; Venable, Demetrius D.; Walker, Monique; Cardirola, Martin; Sakai, Tetsu; Veselovskii, Igor

2013-01-01

Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author.

A review of recent measurements of optical and thermal properties of α-mercuric iodide

NASA Astrophysics Data System (ADS)

Burger, A.; Morgan, S. H.; Silberman, E.; Nason, D.; Cheng, A. Y.

1992-11-01

The band gap energy of α-mercuric iodide was measured recently at elevated temperatures using optical absorption and reflection methods. In addition, reflection spectral measurements indicate that the temperature dependence of the exciton peak can provide a means of measuring, in a nondisturbing and remote manner, the local surface temperature of an α-mercuric iodide crystal during its growth from the vapor. Recent measurements of the thermal diffusivity and thermal expansion tensors have confirmed the anisotropy of this material and have implications for growth morphology and the generation of lattice defects.

A Comparison of Simple Methods to Incorporate Material Temperature Dependency in the Green's Function Method for Estimating Transient Thermal Stresses in Thick-Walled Power Plant Components.

PubMed

Rouse, James; Hyde, Christopher

2016-01-06

The threat of thermal fatigue is an increasing concern for thermal power plant operators due to the increasing tendency to adopt "two-shifting" operating procedures. Thermal plants are likely to remain part of the energy portfolio for the foreseeable future and are under societal pressures to generate in a highly flexible and efficient manner. The Green's function method offers a flexible approach to determine reference elastic solutions for transient thermal stress problems. In order to simplify integration, it is often assumed that Green's functions (derived from finite element unit temperature step solutions) are temperature independent (this is not the case due to the temperature dependency of material parameters). The present work offers a simple method to approximate a material's temperature dependency using multiple reference unit solutions and an interpolation procedure. Thermal stress histories are predicted and compared for realistic temperature cycles using distinct techniques. The proposed interpolation method generally performs as well as (if not better) than the optimum single Green's function or the previously-suggested weighting function technique (particularly for large temperature increments). Coefficients of determination are typically above 0 . 96 , and peak stress differences between true and predicted datasets are always less than 10 MPa.

Temperature-dependent elastic properties of brain tissues measured with the shear wave elastography method.

PubMed

Liu, Yan-Lin; Li, Guo-Yang; He, Ping; Mao, Ze-Qi; Cao, Yanping

2017-01-01

Determining the mechanical properties of brain tissues is essential in such cases as the surgery planning and surgical training using virtual reality based simulators, trauma research and the diagnosis of some diseases that alter the elastic properties of brain tissues. Here, we suggest a protocol to measure the temperature-dependent elastic properties of brain tissues in physiological saline using the shear wave elastography method. Experiments have been conducted on six porcine brains. Our results show that the shear moduli of brain tissues decrease approximately linearly with a slope of -0.041±0.006kPa/°C when the temperature T increases from room temperature (~23°C) to body temperature (~37°C). A case study has been further conducted which shows that the shear moduli are insensitive to the temperature variation when T is in the range of 37 to 43°C and will increase when T is higher than 43°C. With the present experimental setup, temperature-dependent elastic properties of brain tissues can be measured in a simulated physiological environment and a non-destructive manner. Thus the method suggested here offers a unique tool for the mechanical characterization of brain tissues with potential applications in brain biomechanics research. Copyright © 2016 Elsevier Ltd. All rights reserved.

Solar simulators vs outdoor module performance in the Negev Desert

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

Faiman, D

The power output of photovoltaic cells depends on the intensity of the incoming light, its spectral content and the cell temperature. In order to be able to predict the performance of a pv system, therefore, it is of paramount importance to be able to quantify cell performance in a reproducible manner. The standard laboratory technique for this purpose is to employ a solar simulator and a calibrated reference cell. Such a setup enables module performance to be assessed under constant, standard, illumination and temperature conditions. However, this technique has three inherent weaknesses.

Temperature Dependent Electron Transport Properties of Gold Nanoparticles and Composites: Scanning Tunneling Spectroscopy Investigations.

PubMed

Patil, Sumati; Datar, Suwarna; Dharmadhikari, C V

2018-03-01

Scanning tunneling spectroscopy (STS) is used for investigating variations in electronic properties of gold nanoparticles (AuNPs) and its composite with urethane-methacrylate comb polymer (UMCP) as function of temperature. Films are prepared by drop casting AuNPs and UMCP in desired manner on silicon substrates. Samples are further analyzed for morphology under scanning electron microscopy (SEM) and atomic force microscopy (AFM). STS measurements performed in temperature range of 33 °C to 142 °C show systematic variation in current versus voltage (I-V) curves, exhibiting semiconducting to metallic transition/Schottky behavior for different samples, depending upon preparation method and as function of temperature. During current versus time (I-t) measurement for AuNPs, random telegraphic noise is observed at room temperature. Random switching of tunneling current between two discrete levels is observed for this sample. Power spectra derived from I-t show 1/f2 dependence. Statistical analysis of fluctuations shows exponential behavior with time width τ ≈ 7 ms. Local density of states (LDOS) plots derived from I-V curves of each sample show systematic shift in valance/conduction band edge towards/away from Fermi level, with respect to increase in temperature. Schottky emission is best fitted electron emission mechanism for all samples over certain range of bias voltage. Schottky plots are used to calculate barrier heights and temperature dependent measurements helped in measuring activation energies for electron transport in all samples.

Trace-element partition coefficients in the calcite-water system and their paleoclimatic significance in cave studies

NASA Astrophysics Data System (ADS)

Gascoyne, Melvyn

1983-02-01

Speleothems (stalactites, stalagmites) formed in limestone caves have been found to contain much information on the timing and intensity of past climates, from analysis of their U, Th, 13C and 18O contents. Because the incorporation of certain trace elements (e.g., Mg, Mn and Zn) in calcite is known to be temperature-dependent, it may be possible to use variations in trace-metal content of fossil speleothems as an alternative paleotem-perature indicator. Using specially developed ion-exchange sampling techniques, analysis of trace-metal content of seepage water and associated fresh calcite deposits in caves in Vancouver Island and Jamaica shows that Mg is distributed between phases in a consistent manner within the temperature regimes of the caves (7° and 23°C, respectively). Average values of the distribution coefficient for Mg are respectively 0.017 and 0.045 at these temperatures. These results indicate that the Mg content of calcite varies directly with temperature and in a sufficiently pronounced manner that a 1°C rise in depositional temperature of a speleothem containing 500 ppm Mg, at ˜10°C, would be seen as an increase of ˜35ppm Mg — a readily determinable shift. Other factors affecting Mg content of a speleothem are considered.

Apoptotic effects on cultured cells of atmospheric-pressure plasma produced using various gases

NASA Astrophysics Data System (ADS)

Tominami, Kanako; Kanetaka, Hiroyasu; Kudo, Tada-aki; Sasaki, Shota; Kaneko, Toshiro

2016-01-01

This study investigated the effects of low-temperature atmospheric-pressure plasma on various cells such as rat fibroblastic Rat-1 cell line, rat neuroblastoma-like PC12 cell line, and rat macrophage-like NR8383 cell line. The plasma was irradiated directly to a culture medium containing plated cells for 0-20 s. The applied voltage, excitation frequency, and argon or helium gas flow were, respectively, 3-6 kV, 10 kHz, and 3 L/min. Cell viability and apoptotic activity were evaluated using annexin-V/propidium iodide staining. Results showed that the low-temperature atmospheric-pressure plasma irradiation promoted cell death in a discharge-voltage-dependent and irradiation-time-dependent manner. Furthermore, different effects are produced depending on the cell type. Moreover, entirely different mechanisms might be responsible for the induction of apoptosis in cells by helium and argon plasma.

A thermodynamic approach to model the caloric properties of semicrystalline polymers

NASA Astrophysics Data System (ADS)

Lion, Alexander; Johlitz, Michael

2016-05-01

It is well known that the crystallisation and melting behaviour of semicrystalline polymers depends in a pronounced manner on the temperature history. If the polymer is in the liquid state above the melting point, and the temperature is reduced to a level below the glass transition, the final degree of crystallinity, the amount of the rigid amorphous phase and the configurational state of the mobile amorphous phase strongly depend on the cooling rate. If the temperature is increased afterwards, the extents of cold crystallisation and melting are functions of the heating rate. Since crystalline and amorphous phases exhibit different densities, the specific volume depends also on the temperature history. In this article, a thermodynamically based phenomenological approach is developed which allows for the constitutive representation of these phenomena in the time domain. The degree of crystallinity and the configuration of the amorphous phase are represented by two internal state variables whose evolution equations are formulated under consideration of the second law of thermodynamics. The model for the specific Gibbs free energy takes the chemical potentials of the different phases and the mixture entropy into account. For simplification, it is assumed that the amount of the rigid amorphous phase is proportional to the degree of crystallinity. An essential outcome of the model is an equation in closed form for the equilibrium degree of crystallinity in dependence on pressure and temperature. Numerical simulations demonstrate that the process dependences of crystallisation and melting under consideration of the glass transition are represented.

The Nuclear Receptor Rev-erbα Controls Circadian Thermogenic Plasticity

PubMed Central

Gerhart-Hines, Zachary; Everett, Logan J.; Loro, Emanuele; Briggs, Erika R.; Bugge, Anne; Hou, Catherine; Ferrara, Christine; Seale, Patrick; Pryma, Daniel A.; Khurana, Tejvir S.; Lazar, Mitchell A.

2013-01-01

Circadian oscillation of body temperature is a basic, evolutionary-conserved feature of mammalian biology1. Additionally, homeostatic pathways allow organisms to protect their core temperatures in response to cold exposure2. However, the mechanism responsible for coordinating daily body temperature rhythm and adaptability to environmental challenges is unknown. Here we show that the nuclear receptor Rev-erbα, a powerful transcriptional repressor, links circadian and thermogenic networks through the regulation of brown adipose tissue (BAT) function. Mice exposed to cold fare dramatically better at 5 AM (Zeitgeber time 22) when Rev-erbα is barely expressed than at 5 PM (ZT10) when Rev-erbα is abundant. Deletion of Rev-erbα markedly improves cold tolerance at 5 PM, indicating that overcoming Rev-erbα-dependent repression is a fundamental feature of the thermogenic response to cold. Physiological induction of uncoupling protein 1 (UCP1) by cold temperatures is preceded by rapid down-regulation of Rev-erbα in BAT. Rev-erbα represses UCP1 in a brown adipose cell-autonomous manner and BAT UCP1 levels are high in Rev-erbα-null mice even at thermoneutrality. Genetic loss of Rev-erbα also abolishes normal rhythms of body temperature and BAT activity. Thus, Rev-erbα acts as a thermogenic focal point required for establishing and maintaining body temperature rhythm in a manner that is adaptable to environmental demands. PMID:24162845

Anomalous frequency and temperature-dependent scattering and Hund's coupling in the almost quantum critical heavy-fermion system CeFe2Ge2

NASA Astrophysics Data System (ADS)

Bossé, G.; Pan, LiDong; Li, Yize S.; Greene, L. H.; Eckstein, J.; Armitage, N. P.

2016-02-01

We present THz range optical conductivity data of a thin film of the near quantum critical heavy-fermion compound CeFe2Ge2 . Our complex conductivity measurements find a deviation from conventional Drude-like transport in a temperature range previously reported to exhibit unconventional behavior. We calculate the frequency-dependent effective mass and scattering rate using an extended Drude model analysis. We find the inelastic scattering rate can be described by a temperature-dependent power law ωn (T ), where n (T ) approaches ˜1.0 ±0.2 at 1.5 K. This is compared to the ρ ˜T1.5 behavior claimed in dc resistivity data and the ρ ˜T2 expected from Fermi-liquid theory. In addition to a low-temperature mass renormalization, we find an anomalous mass renormalization that persists to high temperature. We attribute this to a Hund's coupling in the Fe states in a manner similar to that recently proposed in the ferropnictides. CeFe2Ge2 appears to be a very interesting system where one may study the interplay between the usual 4 f lattice Kondo effect and this Hund's enhanced Kondo effect in the 3 d states.

Hydrogen fermentation properties of undiluted cow dung.

PubMed

Yokoyama, Hiroshi; Waki, Miyoko; Ogino, Akifumi; Ohmori, Hideyuki; Tanaka, Yasuo

2007-07-01

Anaerobic treatment of undiluted cow dung (15% total solids), so-called dry fermentation, produced hydrogen (743 ml-H(2)/kg-cow dung) at an optimum temperature of 60 degrees C, with butyrate and acetate formation. The hydrogen production was inhibited by the addition of NH(4)(+) in a dose-dependent manner. A bacterium with similarity to Clostridium cellulosi was detected in the fermented dung by a 16S rDNA analysis.

Diode laser measurements of linestrength and temperature-dependent lineshape parameters of H2O-, CO2-, and N2-perturbed H2O transitions near 2474 and 2482 nm

NASA Astrophysics Data System (ADS)

Goldenstein, Christopher S.; Jeffries, Jay B.; Hanson, Ronald K.

2013-11-01

Absorption lineshapes for two unresolved H2O doublets near 4029.52 and 4041.92 cm-1 were measured at high-resolution in a heated static cell using two distributed-feedback diode lasers. Measurements were acquired for H2O, CO2, and N2 perturbers over a temperature and pressure range of 650-1325 K and 2-760 Torr, respectively. Strong collisional narrowing effects were observed in CO2 and N2, but not in pure H2O. The Galatry profile was used to infer collisional-broadening and -narrowing coefficients and their respective temperature dependence for CO2 and N2 perturbers. The collisional-broadening and -narrowing coefficients for CO2 perturbers were found to decrease with increasing temperature in a similar manner. For N2 perturbers, the collisional-broadening coefficients increased with temperature while the collisional-narrowing coefficients decreased with increasing temperature. Self-broadening coefficients were inferred from Voigt profile fits and are compared with HITEMP 2010. The linestrengths of 17 H2O transitions are also reported.

Non-Fermi Liquid Behavior and Continuously Tunable Resistivity Exponents in the Anderson-Hubbard Model at Finite Temperature

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

Patel, Niravkumar D.; Mukherjee, Anamitra; Kaushal, Nitin

Here, we employ a recently developed computational many-body technique to study for the first time the half-filled Anderson-Hubbard model at finite temperature and arbitrary correlation U and disorder V strengths. Interestingly, the narrow zero temperature metallic range induced by disorder from the Mott insulator expands with increasing temperature in a manner resembling a quantum critical point. Our study of the resistivity temperature scaling T α for this metal reveals non-Fermi liquid characteristics. Moreover, a continuous dependence of α on U and V from linear to nearly quadratic is observed. We argue that these exotic results arise from a systematic changemore » with U and V of the “effective” disorder, a combination of quenched disorder and intrinsic localized spins.« less

Effects of kainic acid on rat body temperature: unmasking by dizocilpine.

PubMed

Ahlenius, S; Oprica, M; Eriksson, C; Winblad, B; Schultzberg, M

2002-07-01

The effects of intraperitoneal (i.p.) administration of kainic acid (KA) and dizocilpine, alone or in combination, on body temperature of freely moving rats were examined. Injection of saline or dizocilpine (3.0 or 5.0 mg/kg) was followed after an hour by injection of saline or KA (10 mg/kg) and the body temperature was measured at different time points during the first 5 h. KA alone produced an initial short-lasting hypothermia followed by a longer-lasting hyperthermic effect. Administration of dizocilpine alone produced an early increase in core temperature. Pretreatment of KA-injected rats with dizocilpine potentiated the KA-induced hypothermic effect at 30 min and dose-dependently reduced the temperature measured at 1 h after KA-injection without influencing the ensuing hyperthermia.These data suggest that the KA-induced changes in body temperature do not necessarily involve the activation of NMDA-receptors as opposed to KA-induced behavioural changes that are blocked by dizocilpine in a dose-dependent manner. It is unlikely, therefore, that the KA-induced hyperthermia is a result of the KA-induced seizure motor activity. Furthermore, our findings indicate that KA-induced changes in core temperature may be used as a criterion of drug-responsiveness when the behavioural changes are blocked, e.g. with dizocilpine.

High-frequency sarcomeric auto-oscillations induced by heating in living neonatal cardiomyocytes of the rat

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

Shintani, Seine A.; Oyama, Kotaro; Fukuda, Norio, E-mail: noriof@jikei.ac.jp

2015-02-06

Highlights: • We tested the effects of infra-red laser irradiation on cardiac sarcomere dynamics. • A rise in temperature (>∼38 °C) induced high-frequency sarcomeric auto-oscillations. • These oscillations occurred with and without blockade of intracellular Ca{sup 2+} stores. • Cardiac sarcomeres can play a role as a temperature-dependent rhythm generator. - Abstract: In the present study, we investigated the effects of infra-red laser irradiation on sarcomere dynamics in living neonatal cardiomyocytes of the rat. A rapid increase in temperature to >∼38 °C induced [Ca{sup 2+}]{sub i}-independent high-frequency (∼5–10 Hz) sarcomeric auto-oscillations (Hyperthermal Sarcomeric Oscillations; HSOs). In myocytes with the intactmore » sarcoplasmic reticular functions, HSOs coexisted with [Ca{sup 2+}]{sub i}-dependent spontaneous beating in the same sarcomeres, with markedly varying frequencies (∼10 and ∼1 Hz for the former and latter, respectively). HSOs likewise occurred following blockade of the sarcoplasmic reticular functions, with the amplitude becoming larger and the frequency lower in a time-dependent manner. The present findings suggest that in the mammalian heart, sarcomeres spontaneously oscillate at higher frequencies than the sinus rhythm at temperatures slightly above the physiologically relevant levels.« less

Modeling of surface temperature effects on mixed material migration in NSTX-U

NASA Astrophysics Data System (ADS)

Nichols, J. H.; Jaworski, M. A.; Schmid, K.

2016-10-01

NSTX-U will initially operate with graphite walls, periodically coated with thin lithium films to improve plasma performance. However, the spatial and temporal evolution of these films during and after plasma exposure is poorly understood. The WallDYN global mixed-material surface evolution model has recently been applied to the NSTX-U geometry to simulate the evolution of poloidally inhomogenous mixed C/Li/O plasma-facing surfaces. The WallDYN model couples local erosion and deposition processes with plasma impurity transport in a non-iterative, self-consistent manner that maintains overall material balance. Temperature-dependent sputtering of lithium has been added to WallDYN, utilizing an adatom sputtering model developed from test stand experimental data. Additionally, a simplified temperature-dependent diffusion model has been added to WallDYN so as to capture the intercalation of lithium into a graphite bulk matrix. The sensitivity of global lithium migration patterns to changes in surface temperature magnitude and distribution will be examined. The effect of intra-discharge increases in surface temperature due to plasma heating, such as those observed during NSTX Liquid Lithium Divertor experiments, will also be examined. Work supported by US DOE contract DE-AC02-09CH11466.

Cryptochrome 1 interacts with PIF4 to regulate high temperature-mediated hypocotyl elongation in response to blue light.

PubMed

Ma, Dingbang; Li, Xu; Guo, Yongxia; Chu, Jingfang; Fang, Shuang; Yan, Cunyu; Noel, Joseph P; Liu, Hongtao

2016-01-05

Cryptochrome 1 (CRY1) is a blue light receptor that mediates primarily blue-light inhibition of hypocotyl elongation. Very little is known of the mechanisms by which CRY1 affects growth. Blue light and temperature are two key environmental signals that profoundly affect plant growth and development, but how these two abiotic factors integrate remains largely unknown. Here, we show that blue light represses high temperature-mediated hypocotyl elongation via CRY1. Furthermore, CRY1 interacts directly with PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) in a blue light-dependent manner to repress the transcription activity of PIF4. CRY1 represses auxin biosynthesis in response to elevated temperature through PIF4. Our results indicate that CRY1 signal by modulating PIF4 activity, and that multiple plant photoreceptors [CRY1 and PHYTOCHROME B (PHYB)] and ambient temperature can mediate morphological responses through the same signaling component-PIF4.

Mapping Sensory Spots for Moderate Temperatures on the Back of Hand.

PubMed

Yang, Fan; Chen, Guixu; Zhou, Sikai; Han, Danhong; Xu, Jingjing; Xu, Shengyong

2017-12-04

Thermosensation with thermoreceptors plays an important role in maintaining body temperature at an optimal state and avoiding potential damage caused by harmful hot or cold environmental temperatures. In this work, the locations of sensory spots for sensing moderate temperatures of 40-50 °C on the back of the hands of young Chinese people were mapped in a blind-test manner with a thermal probe of 1.0 mm spatial resolution. The number of sensory spots increased along with the testing temperature; however, the surface density of sensory spots was remarkably lower than those reported previously. The locations of the spots were irregularly distributed and subject-dependent. Even for the same subject, the number and location of sensory spots were unbalanced and asymmetric between the left and right hands. The results may offer valuable information for designing artificial electronic skin and wearable devices, as well as for clinical applications.

Methane spectral line widths and shifts, and dependences on physical parameters

NASA Technical Reports Server (NTRS)

Fox, K.; Quillen, D. T.; Jennings, D. E.; Wagner, J.; Plymate, C.

1991-01-01

A detailed report of the recent high-resolution spectroscopic research on widths and shifts measured for a strong infrared-active fundamental of methane is presented. They were measured in collision with several rare gases and diatomic molecules, in the vibrational-rotational fundamental near 3000/cm. These measurements were made at an ambient temperature of 294 K over a range of pressures from 100 to 700 torr. The measurements are discussed in a preliminary but detailed and quantitative manner with reference to masses, polarizabilities, and quadrupole moments. Some functional dependences on these physical parameters are considered. The present data are useful for studies of corresponding planetary spectra.

Indoor visible mold and mold odor are associated with new-onset childhood wheeze in a dose-dependent manner.

PubMed

Shorter, Caroline; Crane, Julian; Pierse, Nevil; Barnes, Phillipa; Kang, Janice; Wickens, Kristin; Douwes, Jeroen; Stanley, Thorsten; Täubel, Martin; Hyvärinen, Anne; Howden-Chapman, Philippa

2018-01-01

Evidence is accumulating that indoor dampness and mold are associated with the development of asthma. The underlying mechanisms remain unknown. New Zealand has high rates of both asthma and indoor mold and is ideally placed to investigate this. We conducted an incident case-control study involving 150 children with new-onset wheeze, aged between 1 and 7 years, each matched to two control children with no history of wheezing. Each participant's home was assessed for moisture damage, condensation, and mold growth by researchers, an independent building assessor and parents. Repeated measures of temperature and humidity were made, and electrostatic dust cloths were used to collect airborne microbes. Cloths were analyzed using qPCR. Children were skin prick tested for aeroallergens to establish atopy. Strong positive associations were found between observations of visible mold and new-onset wheezing in children (adjusted odds ratios ranged between 1.30 and 3.56; P ≤ .05). Visible mold and mold odor were consistently associated with new-onset wheezing in a dose-dependent manner. Measurements of qPCR microbial levels, temperature, and humidity were not associated with new-onset wheezing. The association between mold and new-onset wheeze was not modified by atopic status, suggesting a non-allergic association. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sfp1 and Rtg3 reciprocally modulate carbon source‐conditional stress adaptation in the pathogenic yeast Candida albicans

PubMed Central

Kastora, Stavroula L.; Herrero‐de‐Dios, Carmen; Avelar, Gabriela M.; Munro, Carol A.

2017-01-01

Summary The pathogenicity of the clinically important yeast, Candida albicans, is dependent on robust responses to host‐imposed stresses. These stress responses have generally been dissected in vitro at 30°C on artificial growth media that do not mimic host niches. Yet host inputs, such as changes in carbon source or temperature, are known to affect C. albicans stress adaptation. Therefore, we performed screens to identify novel regulators that promote stress resistance during growth on a physiologically relevant carboxylic acid and at elevated temperatures. These screens revealed that, under these ‘non‐standard’ growth conditions, numerous uncharacterised regulators are required for stress resistance in addition to the classical Hog1, Cap1 and Cta4 stress pathways. In particular, two transcription factors (Sfp1 and Rtg3) promote stress resistance in a reciprocal, carbon source‐conditional manner. SFP1 is induced in stressed glucose‐grown cells, whereas RTG3 is upregulated in stressed lactate‐grown cells. Rtg3 and Sfp1 regulate the expression of key stress genes such as CTA4, CAP1 and HOG1 in a carbon source‐dependent manner. These mechanisms underlie the stress sensitivity of C. albicans sfp1 cells during growth on glucose, and rtg3 cells on lactate. The data suggest that C. albicans exploits environmentally contingent regulatory mechanisms to retain stress resistance during host colonisation. PMID:28574606

Difference and similarity of dielectric relaxation processes among polyols

NASA Astrophysics Data System (ADS)

Minoguchi, Ayumi; Kitai, Kei; Nozaki, Ryusuke

2003-09-01

Complex permittivity measurements were performed on sorbitol, xylitol, and sorbitol-xylitol mixture in the supercooled liquid state in an extremely wide frequency range from 10 μHz to 500 MHz at temperatures near and above the glass transition temperature. We determined detailed behavior of the relaxation parameters such as relaxation frequency and broadening against temperature not only for the α process but also for the β process above the glass transition temperature, to the best of our knowledge, for the first time. Since supercooled liquids are in the quasi-equilibrium state, the behavior of all the relaxation parameters for the β process can be compared among the polyols as well as those for the α process. The relaxation frequencies of the α processes follow the Vogel-Fulcher-Tammann manner and the loci in the Arrhenius diagram are different corresponding to the difference of the glass transition temperatures. On the other hand, the relaxation frequencies of the β processes, which are often called as the Johari-Goldstein processes, follow the Arrhenius-type temperature dependence. The relaxation parameters for the β process are quite similar among the polyols at temperatures below the αβ merging temperature, TM. However, they show anomalous behavior near TM, which depends on the molecular size of materials. These results suggest that the origin of the β process is essentially the same among the polyols.

Coping with thermal challenges: physiological adaptations to environmental temperatures.

PubMed

Tattersall, Glenn J; Sinclair, Brent J; Withers, Philip C; Fields, Peter A; Seebacher, Frank; Cooper, Christine E; Maloney, Shane K

2012-07-01

Temperature profoundly influences physiological responses in animals, primarily due to the effects on biochemical reaction rates. Since physiological responses are often exemplified by their rate dependency (e.g., rate of blood flow, rate of metabolism, rate of heat production, and rate of ion pumping), the study of temperature adaptations has a long history in comparative and evolutionary physiology. Animals may either defend a fairly constant temperature by recruiting biochemical mechanisms of heat production and utilizing physiological responses geared toward modifying heat loss and heat gain from the environment, or utilize biochemical modifications to allow for physiological adjustments to temperature. Biochemical adaptations to temperature involve alterations in protein structure that compromise the effects of increased temperatures on improving catalytic enzyme function with the detrimental influences of higher temperature on protein stability. Temperature has acted to shape the responses of animal proteins in manners that generally preserve turnover rates at animals' normal, or optimal, body temperatures. Physiological responses to cold and warmth differ depending on whether animals maintain elevated body temperatures (endothermic) or exhibit minimal internal heat production (ectothermic). In both cases, however, these mechanisms involve regulated neural and hormonal over heat flow to the body or heat flow within the body. Examples of biochemical responses to temperature in endotherms involve metabolic uncoupling mechanisms that decrease metabolic efficiency with the outcome of producing heat, whereas ectothermic adaptations to temperature are best exemplified by the numerous mechanisms that allow for the tolerance or avoidance of ice crystal formation at temperatures below 0°C. 2012 American Physiological Society. Compr Physiol 2:2037-2061, 2012.

Feverlike Temperature is a Virulence Regulatory Cue Controlling the Motility and Host Cell Entry of Typhoidal Salmonella.

PubMed

Elhadad, Dana; McClelland, Michael; Rahav, Galia; Gal-Mor, Ohad

2015-07-01

Human infection with typhoidal Salmonella serovars causes a febrile systemic disease, termed enteric fever. Here we establish that in response to a temperature equivalent to fever (39 °C-42 °C) Salmonella enterica serovars Typhi, Paratyphi A, and Sendai significantly attenuate their motility, epithelial cell invasion, and uptake by macrophages. Under these feverlike conditions, the residual epithelial cell invasion of S. Paratyphi A occurs in a type III secretion system (T3SS) 1-independent manner and results in restrained disruption of epithelium integrity. The impaired motility and invasion are associated with down-regulation of T3SS-1 genes and class II and III (but not I) of the flagella-chemotaxis regulon. In contrast, we demonstrate up-regulation of particular Salmonella pathogenicity island 2 genes (especially spiC) and increased intraepithelial growth in a T3SS-2-dependent manner. These results indicate that elevated physiological temperature is a novel cue controlling virulence phenotypes in typhoidal serovars, which is likely to play a role in the distinct clinical manifestations elicited by typhoidal and nontyphoidal salmonellae. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Large scale production of densified hydrogen to the triple point and below

NASA Astrophysics Data System (ADS)

Swanger, A. M.; Notardonato, W. U.; E Fesmire, J.; Jumper, K. M.; Johnson, W. L.; Tomsik, T. M.

2017-12-01

Recent demonstration of advanced liquid hydrogen storage techniques using Integrated Refrigeration and Storage technology at NASA Kennedy Space Center led to the production of large quantities of densified liquid and slush hydrogen in a 125,000 L tank. Production of densified hydrogen was performed at three different liquid levels and LH2 temperatures were measured by twenty silicon diode temperature sensors. Overall densification performance of the system is explored, and solid mass fractions are calculated. Experimental data reveal hydrogen temperatures dropped well below the triple point during testing, and were continuing to trend downward prior to system shutdown. Sub-triple point temperatures were seen to evolve in a time dependent manner along the length of the horizontal, cylindrical vessel. The phenomenon, observed at two fill levels, is detailed herein. The implications of using IRAS for energy storage, propellant densification, and future cryofuel systems are discussed.

Large Scale Production of Densified Hydrogen to the Triple Point and Below

NASA Technical Reports Server (NTRS)

Swanger, A. M.; Notardonato, W. U.; Fesmire, J. E.; Jumper, K. M.; Johnson, W. L.; Tomsik, T. M.

2017-01-01

Recent demonstration of advanced liquid hydrogen storage techniques using Integrated Refrigeration and Storage technology at NASA Kennedy Space Center led to the production of large quantities of densified liquid and slush hydrogen in a 125,000 L tank. Production of densified hydrogen was performed at three different liquid levels and LH2 temperatures were measured by twenty silicon diode temperature sensors. Overall densification performance of the system is explored, and solid mass fractions are calculated. Experimental data reveal hydrogen temperatures dropped well below the triple point during testing, and were continuing to trend downward prior to system shutdown. Sub-triple point temperatures were seen to evolve in a time dependent manner along the length of the horizontal, cylindrical vessel. The phenomenon, observed at two fill levels, is detailed herein. The implications of using IRAS for energy storage, propellant densification, and future cryofuel systems are discussed.

Establishment of Tools for Neurogenetic Analysis of Sexual Behavior in the Silkmoth, Bombyx mori

PubMed Central

Kiya, Taketoshi; Morishita, Koudai; Uchino, Keiro; Iwami, Masafumi; Sezutsu, Hideki

2014-01-01

Background Silkmoth, Bombyx mori, is an ideal model insect for investigating the neural mechanisms underlying sex pheromone-induced innate behavior. Although transgenic techniques and the GAL4/UAS system are well established in the silkmoth, genetic tools useful for investigating brain function at the neural circuit level have been lacking. Results In the present study, we established silkmoth strains in which we could visualize neural projections (UAS-mCD8GFP) and cell nucleus positions (UAS-GFP.nls), and manipulate neural excitability by thermal stimulation (UAS-dTrpA1). In these strains, neural projections and nucleus position were reliably labeled with green fluorescent protein in a GAL4-dependent manner. Further, the behavior of silkworm larvae and adults could be controlled by GAL4-dependent misexpression of dTrpA1. Ubiquitous dTrpA1 misexpression led both silkmoth larvae and adults to exhibit seizure-like phenotypes in a heat stimulation-dependent manner. Furthermore, dTrpA1 misexpression in the sex pheromone receptor neurons of male silkmoths allowed us to control male sexual behavior by changing the temperature. Thermally stimulated male silkmoths exhibited full sexual behavior, including wing-flapping, orientation, and attempted copulation, and precisely approached a thermal source in a manner similar to male silkmoths stimulated with the sex pheromone. Conclusion These findings indicate that a thermogenetic approach using dTrpA1 is feasible in Lepidopteran insects and thermogenetic analysis of innate behavior is applicable in the silkmoth. These tools are essential for elucidating the relationships between neural circuits and function using neurogenetic methods. PMID:25396742

Establishment of tools for neurogenetic analysis of sexual behavior in the silkmoth, Bombyx mori.

PubMed

Kiya, Taketoshi; Morishita, Koudai; Uchino, Keiro; Iwami, Masafumi; Sezutsu, Hideki

2014-01-01

Silkmoth, Bombyx mori, is an ideal model insect for investigating the neural mechanisms underlying sex pheromone-induced innate behavior. Although transgenic techniques and the GAL4/UAS system are well established in the silkmoth, genetic tools useful for investigating brain function at the neural circuit level have been lacking. In the present study, we established silkmoth strains in which we could visualize neural projections (UAS-mCD8GFP) and cell nucleus positions (UAS-GFP.nls), and manipulate neural excitability by thermal stimulation (UAS-dTrpA1). In these strains, neural projections and nucleus position were reliably labeled with green fluorescent protein in a GAL4-dependent manner. Further, the behavior of silkworm larvae and adults could be controlled by GAL4-dependent misexpression of dTrpA1. Ubiquitous dTrpA1 misexpression led both silkmoth larvae and adults to exhibit seizure-like phenotypes in a heat stimulation-dependent manner. Furthermore, dTrpA1 misexpression in the sex pheromone receptor neurons of male silkmoths allowed us to control male sexual behavior by changing the temperature. Thermally stimulated male silkmoths exhibited full sexual behavior, including wing-flapping, orientation, and attempted copulation, and precisely approached a thermal source in a manner similar to male silkmoths stimulated with the sex pheromone. These findings indicate that a thermogenetic approach using dTrpA1 is feasible in Lepidopteran insects and thermogenetic analysis of innate behavior is applicable in the silkmoth. These tools are essential for elucidating the relationships between neural circuits and function using neurogenetic methods.

Influences of the manufacturing process chain design on the near surface condition and the resulting fatigue behaviour of quenched and tempered SAE 4140

NASA Astrophysics Data System (ADS)

Klein, M.; Eifler, D.

2010-07-01

To analyse interactions between single steps of process chains, variations in material properties, especially the microstructure and the resulting mechanical properties, specimens with tension screw geometry were manufactured with five process chains. The different process chains as well as their parameters influence the near surface condition and consequently the fatigue behaviour in a characteristic manner. The cyclic deformation behaviour of these specimens can be benchmarked equivalently with conventional strain measurements as well as with high-precision temperature and electrical resistance measurements. The development of temperature-values provides substantial information on cyclic load dependent changes in the microstructure.

Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137

PubMed Central

Powell, Ryan J.

2013-01-01

Algal biofuels represent one of the most promising means of sustainably replacing liquid fuels. However, significant challenges remain before alga-based fuels become competitive with fossil fuels. One of the largest challenges is the ability to harvest the algae in an economical and low-energy manner. In this article, we describe the isolation of a bacterial strain, Bacillus sp. strain RP1137, which can rapidly aggregate several algae that are candidates for biofuel production, including a Nannochloropsis sp. This bacterium aggregates algae in a pH-dependent and reversible manner and retains its aggregation ability after paraformaldehyde fixation, opening the possibility for reuse of the cells. The optimal ratio of bacteria to algae is described, as is the robustness of aggregation at different salinities and temperatures. Aggregation is dependent on the presence of calcium or magnesium ions. The efficiency of aggregation of Nannochloropsis oceanica IMET1 is between 70 and 95% and is comparable to that obtained by other means of harvest; however, the rate of harvest is fast, with aggregates forming in 30 s. PMID:23892750

Diffusive and subdiffusive dynamics of indoor microclimate: a time series modeling.

PubMed

Maciejewska, Monika; Szczurek, Andrzej; Sikora, Grzegorz; Wyłomańska, Agnieszka

2012-09-01

The indoor microclimate is an issue in modern society, where people spend about 90% of their time indoors. Temperature and relative humidity are commonly used for its evaluation. In this context, the two parameters are usually considered as behaving in the same manner, just inversely correlated. This opinion comes from observation of the deterministic components of temperature and humidity time series. We focus on the dynamics and the dependency structure of the time series of these parameters, without deterministic components. Here we apply the mean square displacement, the autoregressive integrated moving average (ARIMA), and the methodology for studying anomalous diffusion. The analyzed data originated from five monitoring locations inside a modern office building, covering a period of nearly one week. It was found that the temperature data exhibited a transition between diffusive and subdiffusive behavior, when the building occupancy pattern changed from the weekday to the weekend pattern. At the same time the relative humidity consistently showed diffusive character. Also the structures of the dependencies of the temperature and humidity data sets were different, as shown by the different structures of the ARIMA models which were found appropriate. In the space domain, the dynamics and dependency structure of the particular parameter were preserved. This work proposes an approach to describe the very complex conditions of indoor air and it contributes to the improvement of the representative character of microclimate monitoring.

Robust random telegraph conductivity noise in single crystals of the ferromagnetic insulating manganite La0.86Ca0.14MnO3

NASA Astrophysics Data System (ADS)

Przybytek, J.; Fink-Finowicki, J.; Puźniak, R.; Shames, A.; Markovich, V.; Mogilyansky, D.; Jung, G.

2017-03-01

Robust random telegraph conductivity fluctuations have been observed in La0.86Ca0.14MnO3 manganite single crystals. At room temperatures, the spectra of conductivity fluctuations are featureless and follow a 1 /f shape in the entire experimental frequency and bias range. Upon lowering the temperature, clear Lorentzian bias-dependent excess noise appears on the 1 /f background and eventually dominates the spectral behavior. In the time domain, fully developed Lorentzian noise appears as pronounced two-level random telegraph noise with a thermally activated switching rate, which does not depend on bias current and applied magnetic field. The telegraph noise is very robust and persists in the exceptionally wide temperature range of more than 50 K. The amplitude of the telegraph noise decreases exponentially with increasing bias current in exactly the same manner as the sample resistance increases with the current, pointing out the dynamic current redistribution between percolation paths dominated by phase-separated clusters with different conductivity as a possible origin of two-level conductivity fluctuations.

Acoustic near-field characteristics of a conical, premixed flame

NASA Astrophysics Data System (ADS)

Lee, Doh-Hyoung; Lieuwen, Tim C.

2003-01-01

The occurrence of self-excited pressure oscillations routinely plagues the development of combustion systems. These oscillations are often driven by interactions between the flame and acoustic perturbations. This study was performed to characterize the structure of the acoustic field in the near field of the flame and the manner in which it is influenced by oscillation frequency, combustor geometry, flame length and temperature ratio. The results of these calculations indicate that the acoustic velocity has primarily one- and two-dimensional features near the flame tip and base, respectively. The magnitude of the radial velocity components increases with temperature ratio across the flame, while their axial extent increases with frequency. However, the acoustic pressure has primarily one-dimensional characteristics. They also show that the acoustic field structure exhibits only moderate dependencies upon area expansion and flame temperature ratio for values typical of practical systems. Finally, they show that the local characteristics of the acoustic field, as well as the overall plane-wave reflection coefficient, exhibit a decreasing dependence upon the flame length as the area expansion ratio increases.

Acoustic near-field characteristics of a conical, premixed flame.

PubMed

Lee, Doh-Hyoung; Lieuwen, Tim C

2003-01-01

The occurrence of self-excited pressure oscillations routinely plagues the development of combustion systems. These oscillations are often driven by interactions between the flame and acoustic perturbations. This study was performed to characterize the structure of the acoustic field in the near field of the flame and the manner in which it is influenced by oscillation frequency, combustor geometry, flame length and temperature ratio. The results of these calculations indicate that the acoustic velocity has primarily one- and two-dimensional features near the flame tip and base, respectively. The magnitude of the radial velocity components increases with temperature ratio across the flame, while their axial extent increases with frequency. However, the acoustic pressure has primarily one-dimensional characteristics. They also show that the acoustic field structure exhibits only moderate dependencies upon area expansion and flame temperature ratio for values typical of practical systems. Finally, they show that the local characteristics of the acoustic field, as well as the overall plane-wave reflection coefficient, exhibit a decreasing dependence upon the flame length as the area expansion ratio increases.

Structural and biochemical studies on Vibrio cholerae Hsp31 reveals a novel dimeric form and Glutathione-independent Glyoxalase activity

PubMed Central

Dey, Sanjay

2017-01-01

Vibrio cholerae experiences a highly hostile environment at human intestine which triggers the induction of various heat shock genes. The hchA gene product of V. cholerae O395, referred to a hypothetical intracellular protease/amidase VcHsp31, is one such stress-inducible homodimeric protein. Our current study demonstrates that VcHsp31 is endowed with molecular chaperone, amidopeptidase and robust methylglyoxalase activities. Through site directed mutagenesis coupled with biochemical assays on VcHsp31, we have confirmed the role of residues in the vicinity of the active site towards amidopeptidase and methylglyoxalase activities. VcHsp31 suppresses the aggregation of insulin in vitro in a dose dependent manner. Through crystal structures of VcHsp31 and its mutants, grown at various temperatures, we demonstrate that VcHsp31 acquires two (Type-I and Type-II) dimeric forms. Type-I dimer is similar to EcHsp31 where two VcHsp31 monomers associate in eclipsed manner through several intersubunit hydrogen bonds involving their P-domains. Type-II dimer is a novel dimeric organization, where some of the intersubunit hydrogen bonds are abrogated and each monomer swings out in the opposite directions centering at their P-domains, like twisting of wet cloth. Normal mode analysis (NMA) of Type-I dimer shows similar movement of the individual monomers. Upon swinging, a dimeric surface of ~400Å2, mostly hydrophobic in nature, is uncovered which might bind partially unfolded protein substrates. We propose that, in solution, VcHsp31 remains as an equilibrium mixture of both the dimers. With increase in temperature, transformation to Type-II form having more exposed hydrophobic surface, occurs progressively accounting for the temperature dependent increase of chaperone activity of VcHsp31. PMID:28235098

Picosecond-Resolved Fluorescent Probes at Functionally Distinct Tryptophans within a Thermophilic Alcohol Dehydrogenase: Relationship of Temperature-Dependent Changes in Fluorescence to Catalysis

PubMed Central

2015-01-01

Two single-tryptophan variants were generated in a thermophilic alcohol dehydrogenase with the goal of correlating temperature-dependent changes in local fluorescence with the previously demonstrated catalytic break at ca. 30 °C (Kohen et al., Nature1999, 399, 496). One tryptophan variant, W87in, resides at the active site within van der Waals contact of bound alcohol substrate; the other variant, W167in, is a remote-site surface reporter located >25 Å from the active site. Picosecond-resolved fluorescence measurements were used to analyze fluorescence lifetimes, time-dependent Stokes shifts, and the extent of collisional quenching at Trp87 and Trp167 as a function of temperature. A subnanosecond fluorescence decay rate constant has been detected for W87in that is ascribed to the proximity of the active site Zn2+ and shows a break in behavior at 30 °C. For the remainder of the reported lifetime measurements, there is no detectable break between 10 and 50 °C, in contrast with previously reported hydrogen/deuterium exchange experiments that revealed a temperature-dependent break analogous to catalysis (Liang et al., Proc. Natl. Acad. Sci. U.S.A. 2004, 101, 9556). We conclude that the motions that lead to the rigidification of ht-ADH below 30 °C are likely to be dominated by global processes slower than the picosecond to nanosecond motions measured herein. In the case of collisional quenching of fluorescence by acrylamide, W87in and W167in behave in a similar manner that resembles free tryptophan in water. Stokes shift measurements, by contrast, show distinctive behaviors in which the active-site tryptophan relaxation is highly temperature-dependent, whereas the solvent-exposed tryptophan’s dynamics are temperature-independent. These data are concluded to reflect a significantly constrained environment surrounding the active site Trp87 that both increases the magnitude of the Stokes shift and its temperature-dependence. The results are discussed in the context of spatially distinct differences in enthalpic barriers for protein conformational sampling that may be related to catalysis. PMID:24892947

Negative differential transconductance in silicon quantum well metal-oxide-semiconductor field effect/bipolar hybrid transistors

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

Naquin, Clint; Lee, Mark; Edwards, Hal

2014-11-24

Introducing explicit quantum transport into Si transistors in a manner amenable to industrial fabrication has proven challenging. Hybrid field-effect/bipolar Si transistors fabricated on an industrial 45 nm process line are shown to demonstrate explicit quantum transport signatures. These transistors incorporate a lateral ion implantation-defined quantum well (QW) whose potential depth is controlled by a gate voltage (V{sub G}). Quantum transport in the form of negative differential transconductance (NDTC) is observed to temperatures >200 K. The NDTC is tied to a non-monotonic dependence of bipolar current gain on V{sub G} that reduces drain-source current through the QW. These devices establish the feasibility ofmore » exploiting quantum transport to transform the performance horizons of Si devices fabricated in an industrially scalable manner.« less

Quantitative observations of hydrogen-induced, slow crack growth in a low alloy steel

NASA Technical Reports Server (NTRS)

Nelson, H. G.; Williams, D. P.

1973-01-01

Hydrogen-induced slow crack growth, da/dt, was studied in AISI-SAE 4130 low alloy steel in gaseous hydrogen and distilled water environments as a function of applied stress intensity, K, at various temperatures, hydrogen pressures, and alloy strength levels. At low values of K, da/dt was found to exhibit a strong exponential K dependence (Stage 1 growth) in both hydrogen and water. At intermediate values of K, da/dt exhibited a small but finite K dependence (Stage 2), with the Stage 2 slope being greater in hydrogen than in water. In hydrogen, at a constant K, (da/dt) sub 2 varied inversely with alloy strength level and varied essentially in the same complex manner with temperature and hydrogen pressure as noted previously. The results of this study provide support for most of the qualitative predictions of the lattice decohesion theory as recently modified by Oriani. The lack of quantitative agreement between data and theory and the inability of theory to explain the observed pressure dependence of slow crack growth are mentioned and possible rationalizations to account for these differences are presented.

Cryptochrome 1 interacts with PIF4 to regulate high temperature-mediated hypocotyl elongation in response to blue light

PubMed Central

Ma, Dingbang; Li, Xu; Guo, Yongxia; Chu, Jingfang; Fang, Shuang; Yan, Cunyu; Noel, Joseph P.; Liu, Hongtao

2016-01-01

Cryptochrome 1 (CRY1) is a blue light receptor that mediates primarily blue-light inhibition of hypocotyl elongation. Very little is known of the mechanisms by which CRY1 affects growth. Blue light and temperature are two key environmental signals that profoundly affect plant growth and development, but how these two abiotic factors integrate remains largely unknown. Here, we show that blue light represses high temperature-mediated hypocotyl elongation via CRY1. Furthermore, CRY1 interacts directly with PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) in a blue light-dependent manner to repress the transcription activity of PIF4. CRY1 represses auxin biosynthesis in response to elevated temperature through PIF4. Our results indicate that CRY1 signal by modulating PIF4 activity, and that multiple plant photoreceptors [CRY1 and PHYTOCHROME B (PHYB)] and ambient temperature can mediate morphological responses through the same signaling component—PIF4. PMID:26699514

Complementary Response of Static Spin-Stripe Order and Superconductivity to Nonmagnetic Impurities in Cuprates

DOE PAGES

Guguchia, Z.; Roessli, B.; Khasanov, R.; ...

2017-08-22

Here, we report muon-spin rotation and neutron-scattering experiments on nonmagnetic Zn impurity effects on the static spin-stripe order and superconductivity of the La214 cuprates. Remarkably, it was found that, for samples with hole doping x≈1/8, the spin-stripe ordering temperature T so decreases linearly with Zn doping y and disappears at y≈4%, demonstrating a high sensitivity of static spin-stripe order to impurities within a CuO 2 plane. Moreover, Tso is suppressed by Zn in the same manner as the superconducting transition temperature Tc for samples near optimal hole doping. This surprisingly similar sensitivity suggests that the spin-stripe order is dependent onmore » intertwining with superconducting correlations.« less

Complementary Response of Static Spin-Stripe Order and Superconductivity to Nonmagnetic Impurities in Cuprates

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

Guguchia, Z.; Roessli, B.; Khasanov, R.

Here, we report muon-spin rotation and neutron-scattering experiments on nonmagnetic Zn impurity effects on the static spin-stripe order and superconductivity of the La214 cuprates. Remarkably, it was found that, for samples with hole doping x≈1/8, the spin-stripe ordering temperature T so decreases linearly with Zn doping y and disappears at y≈4%, demonstrating a high sensitivity of static spin-stripe order to impurities within a CuO 2 plane. Moreover, Tso is suppressed by Zn in the same manner as the superconducting transition temperature Tc for samples near optimal hole doping. This surprisingly similar sensitivity suggests that the spin-stripe order is dependent onmore » intertwining with superconducting correlations.« less

Single-backscattering and quasi-single-backscattering of low energy ions from a cold nickel surface: contribution to the ICISS method

NASA Astrophysics Data System (ADS)

Soszka, W.

1992-09-01

Energy spectra of 5 keV Ne+ and He+ ions backscattered from the cold (100) nickel surface for chosen values of the incidence angles were measured. It was found that the occurrence of the isotope structure of the so-called "single-scattering" peak as well as its position on the energy scale depend on the incidence angle and the target temperature. In comparison to the case of room temperature the "ICISS curve" (the intensity of the single-scattering peak versus the incidence angle) at low temperatures increases up to relatively large angles. The curve in its part shows some structure which is not observed at room temperatures. It has been shown [E.S. Parilis et al., Atomic Collisions in Gases and on Solid Surfaces (FAN, Tashkent, 1988) in Russian] that the doubly scattered ions can have the same energy and exit angle as the singly scattered ions and both components create the quasi-single-scattering peak. The double-scattering component depends in a complex manner on the incidence angle and the target temperature. It is shown that at low temperatures (below 80 K) the intensity of the single-scattering component decreases (a decrease of thermal cross section), and the intensity of the double-scattering component relatively increases. This determines the behaviour of the ICISS curve, which, for low temperatures and light projectiles cannot be treated as a real ICISS curve.

An apple NAC transcription factor negatively regulates cold tolerance via CBF-dependent pathway.

PubMed

An, Jian-Ping; Li, Rui; Qu, Feng-Jia; You, Chun-Xiang; Wang, Xiao-Fei; Hao, Yu-Jin

2018-02-01

Cold stress is an adverse stimulus that affects plant growth and development, and the C-repeat binding factor (CBF) cold-regulatory cascade has been regarded as a master regulator in the plant response to cold stress. Here, we showed that a NAC transcription factor modulated low-temperature tolerance. MdNAC029/MdNAP, an apple NAC gene was isolated and its role in regulating cold tolerance was investigated. MdNAC029 was responsive to low-temperature treatment, and over-expression of MdNAC029 reduced cold tolerance in apple calli and Arabidopsis. Furthermore, EMSA assays and transient expression assays demonstrated that MdNAC029 directly repressed the expression of MdCBF1 and MdCBF4 by binding to their promoters. Taken together, our data suggest that MdNAC029 functions as a negative regulator in regulating plant cold tolerance in a CBF-dependent manner, providing a deeper understanding of NAC transcription-factor-mediated cold tolerance. Copyright © 2017 Elsevier GmbH. All rights reserved.

Gold ink coating of thermocouple sheaths

DOEpatents

Ruhl, H. Kenneth

1992-01-01

A method is provided for applying a gold ink coating to a thermocouple sheath which includes the steps of electropolishing and oxidizing the surface of the thermocouple sheath, then dipping the sheath into liquid gold ink, and finally heat curing the coating. The gold coating applied in this manner is highly reflective and does not degrade when used for an extended period of time in an environment having a temperature over 1000.degree. F. Depending on the application, a portion of the gold coating covering the tip of the thermocouple sheath is removed by abrasion.

Effects of Solvent and Temperature on Free Radical Formation in Electronic Cigarette Aerosols.

PubMed

Bitzer, Zachary T; Goel, Reema; Reilly, Samantha M; Foulds, Jonathan; Muscat, Joshua; Elias, Ryan J; Richie, John P

2018-01-16

The ever-evolving market of electronic cigarettes (e-cigarettes) presents a challenge for analyzing and characterizing the harmful products they can produce. Earlier we reported that e-cigarette aerosols can deliver high levels of reactive free radicals; however, there are few data characterizing the production of these potentially harmful oxidants. Thus, we have performed a detailed analysis of the different parameters affecting the production of free radical by e-cigarettes. Using a temperature-controlled e-cigarette device and a novel mechanism for reliably simulating e-cigarette usage conditions, including coil activation and puff flow, we analyzed the effects of temperature, wattage, and e-liquid solvent composition of propylene glycol (PG) and glycerol (GLY) on radical production. Free radicals in e-cigarette aerosols were spin-trapped and analyzed using electron paramagnetic resonance. Free radical production increased in a temperature-dependent manner, showing a nearly 2-fold increase between 100 and 300 °C under constant-temperature conditions. Free radical production under constant wattage showed an even greater increase when going from 10 to 50 W due, in part, to higher coil temperatures compared to constant-temperature conditions. The e-liquid PG content also heavily influenced free radical production, showing a nearly 3-fold increase upon comparison of ratios of 0:100 (PG:GLY) and 100:0 (PG:GLY). Increases in PG content were also associated with increases in aerosol-induced oxidation of biologically relevant lipids. These results demonstrate that the production of reactive free radicals in e-cigarette aerosols is highly solvent dependent and increases with an increase in temperature. Radical production was somewhat dependent on aerosol production at higher temperatures; however, disproportionately high levels of free radicals were observed at ≥100 °C despite limited aerosol production. Overall, these findings suggest that e-cigarettes can be designed to minimize exposure to these potentially harmful products.

Novel HCN2 mutation contributes to febrile seizures by shifting the channel's kinetics in a temperature-dependent manner.

PubMed

Nakamura, Yuki; Shi, Xiuyu; Numata, Tomohiro; Mori, Yasuo; Inoue, Ryuji; Lossin, Christoph; Baram, Tallie Z; Hirose, Shinichi

2013-01-01

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel-mediated currents, known as I h, are involved in the control of rhythmic activity in neuronal circuits and in determining neuronal properties including the resting membrane potential. Recent studies have shown that HCN channels play a role in seizure susceptibility and in absence and limbic epilepsy including temporal lobe epilepsy following long febrile seizures (FS). This study focused on the potential contributions of abnormalities in the HCN2 isoform and their role in FS. A novel heterozygous missense mutation in HCN2 exon 1 leading to p.S126L was identified in two unrelated patients with FS. The mutation was inherited from the mother who had suffered from FS in a pedigree. To determine the effect of this substitution we conducted whole-cell patch clamp electrophysiology. We found that mutant channels had elevated sensitivity to temperature. More specifically, they displayed faster kinetics at higher temperature. Kinetic shift by change of temperature sensitivity rather than the shift of voltage dependence led to increased availability of I h in conditions promoting FS. Responses to cyclic AMP did not differ between wildtype and mutant channels. Thus, mutant HCN2 channels cause significant cAMP-independent enhanced availability of I h during high temperatures, which may contribute to hyperthermia-induced neuronal hyperexcitability in some individuals with FS.

Is age-dependent, ketamine-induced apoptosis in the rat somatosensory cortex influenced by temperature?

PubMed Central

Gutierrez, Silvia; Carnes, Ansley; Finucane, Beth; Oelsner, Gabrielle Musci William; Hicks, Lucretia; Russell, Gregory B.; Liu, Chun; Turner, Christopher P.

2010-01-01

General anesthetics have long been thought to be relatively safe but recent clinical studies have revealed that exposure of very young children (4 years or less) to agents that act by blocking the N-methyl-D-aspartate receptor (NMDAR) can lead to cognitive deficits as they mature. In rodent and non-human primate studies, blockade of this receptor during the perinatal period leads to a number of molecular, cellular and behavioral pathologies. Despite the overwhelming evidence from such studies, doubt remains as to their clinical relevance. A key issue is whether the primary injury (apoptotic cell death) is specific to receptor blockade or due to non-specific, patho-physiological changes. Principal to this argument is that loss of core body temperature following NMDAR blockade could explain why injury is observed hours later. We therefore examined the neurotoxicity of the general anesthetic ketamine in P7, P14 and P21 rats while monitoring core body temperature. We found that, at P7, ketamine induced the pro-apoptotic enzyme activated caspase-3 in a dose-dependent manner. As expected, injury was greatly diminished by P14 and absent by P21. However, contrary to expectations, we found that core body temperature was not a factor in determining injury. Our data imply that injury is directly related to receptor blockade and is unlikely to be overcome by artificially changing core body temperature. PMID:20298758

Oolong tea prevents cardiomyocyte loss against hypoxia by attenuating p-JNK mediated hypertrophy and enhancing P-IGF1R, p-akt, and p-Badser136 activity and by fortifying NRF2 antioxidation system.

PubMed

Shibu, Marthandam Asokan; Kuo, Chia-Hua; Chen, Bih-Cheng; Ju, Da-Tong; Chen, Ray-Jade; Lai, Chao-Hung; Huang, Pei-Jane; Viswanadha, Vijaya Padma; Kuo, Wei-Wen; Huang, Chih-Yang

2018-02-01

Tea, the most widely consumed natural beverage has been associated with reduced mortality risk from cardiovascular disease. Oolong tea is a partially fermented tea containing high levels of catechins, their degree of oxidation varies between 20%-80% causing differences in their active metabolites. In this study we examined the effect of oolong tea extract (OTE) obtained by oxidation at low-temperature for short-time against hypoxic injury and found that oolong tea provides cyto-protective effects by suppressing the JNK mediated hypertrophic effects and by enhancing the innate antioxidant mechanisms in neonatal cardiomyocytes and in H9c2 cells. OTE effectively attenuates 24 h hypoxia-triggered cardiomyocyte loss by suppressing caspase-3-cleavage and apoptosis in a dose-dependent manner. OTE also enhances the IGFIR/p-Akt associated survival-mechanism involving the elevation of p-Bad ser136 in a dose-dependent manner to aid cellular adaptations against hypoxic challenge. The results show the effects and mechanism of Oolong tea to provide cardio-protective benefits during hypoxic conditions. © 2017 Wiley Periodicals, Inc.

Temperature control of the ultra-short laser pulse compression in a one-dimensional photonic band gap structure with nematic liquid crystal as a defect layer

NASA Astrophysics Data System (ADS)

Shiri, Ramin; Safari, Ebrahim; Bananej, Alireza

2018-04-01

We investigate numerically the controllable chirped pulse compression in a one-dimensional photonic structure containing a nematic liquid crystal defect layer using the temperature dependent refractive index of the liquid crystal. We consider the structure under irradiation by near-infrared ultra-short laser pulses polarized parallel to the liquid crystal director at a normal angle of incidence. It is found that the dispersion behaviour and consequently the compression ability of the system can be changed in a controlled manner due to the variation in the defect temperature. When the temperature increased from 290 to 305 K, the transmitted pulse duration decreased from 75 to 42 fs in the middle of the structure, correspondingly. As a result, a novel low-loss tunable pulse compressor with a really compact size and high compression factor is achieved. The so-called transfer matrix method is utilized for numerical simulations of the band structure and reflection/transmission spectra of the structure under investigation.

Assembly properties of the Bacillus subtilis actin, MreB.

PubMed

Mayer, Joshua A; Amann, Kurt J

2009-02-01

The bacterial actin MreB has been implicated in a variety of cellular roles including cell shape determination, cell wall synthesis, chromosome condensation and segregation, and the establishment and maintenance of cell polarity. Toward elucidating a clearer understanding of how MreB functions inside the bacterial cell, we investigated biochemically the polymerization of MreB from Bacillus subtilis. Light scattering and sedimentation assays revealed pH-, ionic-, cationic-, and temperature-dependent behavior. B. subtilis MreB polymerizes in the presence of millimolar divalent cations in a protein concentration-dependent manner. Polymerization is favored by decreasing pH and inhibited by monovalent salts and low temperatures. Although B. subtilis MreB binds and hydrolyzes both ATP and GTP, it does not require a bound nucleotide for assembly and polymerizes indistinguishably regardless of the nucleotide species bound, with a critical concentration of approximately 900 nM. A number of the presently reported properties of B. subtilis MreB differ significantly from those of T. maritima MreB1 (Bean and Amann [2008]: Biochemistry 47: 826-835), including the nucleotide requirements and temperature and ionic effects on polymerization state. These observations collectively suggest that additional factors interact with MreB to account for its complex dynamic behavior in cells.

Modifying the baricity of local anesthetics for spinal anesthesia by temperature adjustment: model calculations.

PubMed

Heller, Axel R; Zimmermann, Katrin; Seele, Kristin; Rössel, Thomas; Koch, Thea; Litz, Rainer J

2006-08-01

Although local anesthetics (LAs) are hyperbaric at room temperature, density drops within minutes after administration into the subarachnoid space. LAs become hypobaric and therefore may cranially ascend during spinal anesthesia in an uncontrolled manner. The authors hypothesized that temperature and density of LA solutions have a nonlinear relation that may be described by a polynomial equation, and that conversion of this equation may provide the temperature at which individual LAs are isobaric. Density of cerebrospinal fluid was measured using a vibrating tube densitometer. Temperature-dependent density data were obtained from all LAs commonly used for spinal anesthesia, at least in triplicate at 5 degrees, 20 degrees, 30 degrees, and 37 degrees C. The hypothesis was tested by fitting the obtained data into polynomial mathematical models allowing calculations of substance-specific isobaric temperatures. Cerebrospinal fluid at 37 degrees C had a density of 1.000646 +/- 0.000086 g/ml. Three groups of local anesthetics with similar temperature (T, degrees C)-dependent density (rho) characteristics were identified: articaine and mepivacaine, rho1(T) = 1.008-5.36 E-06 T2 (heavy LAs, isobaric at body temperature); L-bupivacaine, rho2(T) = 1.007-5.46 E-06 T2 (intermediate LA, less hypobaric than saline); bupivacaine, ropivacaine, prilocaine, and lidocaine, rho3(T) = 1.0063-5.0 E-06 T (light LAs, more hypobaric than saline). Isobaric temperatures (degrees C) were as follows: 5 mg/ml bupivacaine, 35.1; 5 mg/ml L-bupivacaine, 37.0; 5 mg/ml ropivacaine, 35.1; 20 mg/ml articaine, 39.4. Sophisticated measurements and mathematic models now allow calculation of the ideal injection temperature of LAs and, thus, even better control of LA distribution within the cerebrospinal fluid. The given formulae allow the adaptation on subpopulations with varying cerebrospinal fluid density.

Trypanosoma cruzi, Etiological Agent of Chagas Disease, Is Virulent to Its Triatomine Vector Rhodnius prolixus in a Temperature-Dependent Manner

PubMed Central

Elliot, Simon L.; Rodrigues, Juliana de O.; Lorenzo, Marcelo G.; Martins-Filho, Olindo A.; Guarneri, Alessandra A.

2015-01-01

It is often assumed that parasites are not virulent to their vectors. Nevertheless, parasites commonly exploit their vectors (nutritionally for example) so these can be considered a form of host. Trypanosoma cruzi, a protozoan found in mammals and triatomine bugs in the Americas, is the etiological agent of Chagas disease that affects man and domestic animals. While it has long been considered avirulent to its vectors, a few reports have indicated that it can affect triatomine fecundity. We tested whether infection imposed a temperature-dependent cost on triatomine fitness. We held infected insects at four temperatures between 21 and 30°C and measured T. cruzi growth in vitro at the same temperatures in parallel. Trypanosoma cruzi infection caused a considerable delay in the time the insects took to moult (against a background effect of temperature accelerating moult irrespective of infection status). Trypanosoma cruzi also reduced the insects’ survival, but only at the intermediate temperatures of 24 and 27°C (against a background of increased mortality with increasing temperatures). Meanwhile, in vitro growth of T. cruzi increased with temperature. Our results demonstrate virulence of a protozoan agent of human disease to its insect vector under these conditions. It is of particular note that parasite-induced mortality was greatest over the range of temperatures normally preferred by these insects, probably implying adaptation of the parasite to perform well at these temperatures. Therefore we propose that triggering this delay in moulting is adaptive for the parasites, as it will delay the next bloodmeal taken by the bug, thus allowing the parasites time to develop and reach the insect rectum in order to make transmission to a new vertebrate host possible. PMID:25793495

Population Dynamics of Viral Inactivation

NASA Astrophysics Data System (ADS)

Freeman, Krista; Li, Dong; Behrens, Manja; Streletzky, Kiril; Olsson, Ulf; Evilevitch, Alex

We have investigated the population dynamics of viral inactivation in vitrousing time-resolved cryo electron microscopy combined with light and X-ray scattering techniques. Using bacteriophage λ as a model system for pressurized double-stranded DNA viruses, we found that virions incubated with their cell receptor eject their genome in a stochastic triggering process. The triggering of DNA ejection occurs in a non synchronized manner after the receptor addition, resulting in an exponential decay of the number of genome-filled viruses with time. We have explored the characteristic time constant of this triggering process at different temperatures, salt conditions, and packaged genome lengths. Furthermore, using the temperature dependence we determined an activation energy for DNA ejections. The dependences of the time constant and activation energy on internal DNA pressure, affected by salt conditions and encapsidated genome length, suggest that the triggering process is directly dependent on the conformational state of the encapsidated DNA. The results of this work provide insight into how the in vivo kinetics of the spread of viral infection are influenced by intra- and extra cellular environmental conditions. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1252522.

Marangoni convection in Casson liquid flow due to an infinite disk with exponential space dependent heat source and cross-diffusion effects

NASA Astrophysics Data System (ADS)

Mahanthesh, B.; Gireesha, B. J.; Shashikumar, N. S.; Hayat, T.; Alsaedi, A.

2018-06-01

Present work aims to investigate the features of the exponential space dependent heat source (ESHS) and cross-diffusion effects in Marangoni convective heat mass transfer flow due to an infinite disk. Flow analysis is comprised with magnetohydrodynamics (MHD). The effects of Joule heating, viscous dissipation and solar radiation are also utilized. The thermal and solute field on the disk surface varies in a quadratic manner. The ordinary differential equations have been obtained by utilizing Von Kármán transformations. The resulting problem under consideration is solved numerically via Runge-Kutta-Fehlberg based shooting scheme. The effects of involved pertinent flow parameters are explored by graphical illustrations. Results point out that the ESHS effect dominates thermal dependent heat source effect on thermal boundary layer growth. The concentration and temperature distributions and their associated layer thicknesses are enhanced by Marangoni effect.

Stark shift of impurity doped quantum dots: Role of noise

NASA Astrophysics Data System (ADS)

Arif, Sk. Md.; Bera, Aindrila; Ghosh, Anuja; Ghosh, Manas

2018-02-01

Present study makes a punctilious investigation of the profiles of Stark shift (SS) of doped GaAs quantum dot (QD) under the supervision of Gaussian white noise. A few physical parameters have been varied and the consequent variations in the SS profiles have been monitored. The said physical parameters comprise of magnetic field, confinement potential, dopant location, dopant potential, noise strength, aluminium concentration (only for AlxGa1-x As alloy QD), position-dependent effective mass (PDEM), position-dependent dielectric screening function (PDDSF), anisotropy, hydrostatic pressure (HP) and temperature. The SS profiles unfurl interesting features that heavily depend upon the particular physical quantity concerned, presence/absence of noise and the manner (additive/multiplicative) noise enters the system. The study highlights feasible means of maximizing SS of doped QD in presence of noise by suitable adjustment of several control parameters. The study deems importance in view of technological applications of QD devices where noise plays some prominent role.

Large Scale Production of Densified Hydrogen Using Integrated Refrigeration and Storage

NASA Technical Reports Server (NTRS)

Notardonato, William U.; Swanger, Adam Michael; Jumper, Kevin M.; Fesmire, James E.; Tomsik, Thomas M.; Johnson, Wesley L.

2017-01-01

Recent demonstration of advanced liquid hydrogen storage techniques using Integrated Refrigeration and Storage (IRAS) technology at NASA Kennedy Space Center led to the production of large quantities of solid densified liquid and slush hydrogen in a 125,000 L tank. Production of densified hydrogen was performed at three different liquid levels and LH2 temperatures were measured by twenty silicon diode temperature sensors. System energy balances and solid mass fractions are calculated. Experimental data reveal hydrogen temperatures dropped well below the triple point during testing (up to 1 K), and were continuing to trend downward prior to system shutdown. Sub-triple point temperatures were seen to evolve in a time dependent manner along the length of the horizontal, cylindrical vessel. Twenty silicon diode temperature sensors were recorded over approximately one month for testing at two different fill levels (33 67). The phenomenon, observed at both two fill levels, is described and presented detailed and explained herein., and The implications of using IRAS for energy storage, propellant densification, and future cryofuel systems are discussed.

Four kingdoms on glacier ice: convergent energetic processes boost energy levels as temperatures fall.

PubMed Central

Napolitano, Michael J; Shain, Daniel H

2004-01-01

A diverse group of glacially obligate organisms coexist on temperate glaciers between Washington State and Alaska. A fundamental challenge for these and other cold-adapted species is the necessity to maintain an energy flux capable of sustaining life at low physiological temperatures. We show here that ice-adapted psychrophiles from four kingdoms (Animalia, Eubacteria, Fungi, Protista) respond to temperature fluctuations in a similar manner; namely, ATP levels and the total adenylate pool increase as temperatures fall (within their viable temperature limits, respectively), yet growth rate increases with temperature. By contrast, mesophilic representatives of each kingdom respond in an opposite manner (i.e. adenylates increase with temperature). These observations suggest that elevated adenylate levels in psychrophiles may offset inherent reductions in molecular diffusion at low physiological temperatures. PMID:15503992

Fractionation of lithium isotopes in magmatic systems as a natural consequence of cooling

NASA Astrophysics Data System (ADS)

Gallagher, Kerry; Elliott, Tim

2009-02-01

High-temperature, diffusive fractionation has been invoked to account for striking Li isotopic variability recently observed within individual phenocrysts and xenolith minerals. It has been argued that chemical potential gradients required to drive such diffusion arise from changes in Li partitioning between coexisting phases during cooling. If so, Li isotopic zoning should be a common occurrence but the role of temperature-dependent partition coefficients in generating Li isotopic variability remains to be tested in a quantitative manner. Here we consider a basic scenario of a phenocryst in a cooling lava, using simple parameterisations of the temperature dependence of Li partitioning and diffusivity in clinopyroxene. Our model initially produces an asymmetric isotope profile across the crystal with a δ7Li minimum that remains close to the edge of a crystal. Such a distinctive shape mimics Li isotopic profiles documented in some olivine and clinopyroxene phenocrysts, which have isotopically normal cores but anomalously light rims. The temperature dependence of both the diffusivity and the partition coefficient of Li are key factors in generating this form of diffusion profile. Continued diffusion leads to an inversion in the sense of isotopic change between core and rim and results in the whole phenocryst attaining markedly light isotopic values. Our calculations show that significant Li isotopic zoning can occur as a natural consequence of cooling magmatic systems. Crystals that have experienced more complex thermal histories (e.g. re-entrained cumulates versus true phenocrysts) will therefore exhibit contrasting isotopic profiles and, as such, these data may be useful for tracing sub-volcanic processes.

Reference Correlation for the Viscosity of Ammonia from the Triple Point to 725 K and up to 50 MPa

NASA Astrophysics Data System (ADS)

Monogenidou, S. A.; Assael, M. J.; Huber, M. L.

2018-06-01

This paper presents a new wide-ranging correlation for the viscosity of ammonia based on critically evaluated experimental data. The correlation is designed to be used with a recently developed equation of state, and it is valid from the triple point to 725 K at pressures up to 50 MPa. The estimated uncertainty varies depending on the temperature and pressure, from 0.6% to 5%. The correlation behaves in a physically reasonable manner when extrapolated to 100 MPa; however, care should be taken when using the correlation outside of the validated range.

Theoretical analysis of non-linear Joule heating effects over an electro-thermal patterned flow

NASA Astrophysics Data System (ADS)

Sanchez, Salvador; Ascanio, Gabriel; Mendez, Federico; Bautista, Oscar

2017-11-01

In this work, non-linear Joule heating effects for electro-thermal patterned flows driven inside of a slit microchannel are analyzed. Here, the movement of fluids is controlled by placing electro-thermal forces, which are generated through an imposed longitudinal electric field, E0, and the wall electric potential produced by electrodes inserted along the surface of the microchannel wall, ζ. For this analysis, viscosity and electrical conductivity of fluids are included as known functions, which depend on the temperature; therefore, in order to determine the flow, temperature and electric potential fields together with its simultaneous interactions, the equations of continuity, momentum, energy, charges distribution and electrical current have to be solved in a coupled manner. The main results obtained in the study reveal that with the presence of thermal gradients along of the microchannel, local electro-thermal forces, Fχ, are affected in a sensible manner, and consequently, the flow field is modified substantially, causing the interruption or intensification of recirculations along of the microchannel. This work was supported by the Fondo SEP-CONACYT through research Grants No. 220900 and 20171181 from SIP-IPN. F. Mendez acknowledges support from PAPIIT-UNAM under Contract Number IN112215. S. Sanchez thanks to DGAPA-UNAM for the postdoctoral fellowship.

Transverse transport of Fe3O4-H2O with viscosity variation under pure internal heating

NASA Astrophysics Data System (ADS)

Mehmood, Rashid; Tabassum, R.

2018-05-01

Smart fluids are the fluids whose properties can be changed by applying an electric or a magnetic field. Such type of fluid finds tremendous applications in electronic devices, semi-active dampers, magnetic resonance imaging, in space craft propulsion and many more. This communication addresses water based magneto ferrofluid striking at a stretching surface in an oblique manner. In order to present physically realistic analysis, viscosity is assumed to be dependent upon temperature as well as volume fraction of magnetite nanoparticle. The flow governing problem is altered into nonlinear coupled system of ordinary differential equations via scaling transformation which is then solved numerically by means of Runge-kutta Fehlberg scheme. Impact of sundry parameters such as magnetic field parameter, nanoparticle volume fraction, heat generation parameter and variable viscosity parameter on velocity and temperature profile of magneto ferrofluid is presented graphically and discussed in a physical manner. Practical measures of interest namely skin friction and heat flux at the surface are computed. Streamline patterns are traced out to examine the flow pattern. It is found that skin friction and rate of heat transfer at the wall enhances by strengthening the applied magnetic field. Local heat flux can also be enhanced with increasing the volume fraction of magnetite nanoparticles.

Elevating body temperature enhances hematopoiesis and neutrophil recovery after total body irradiation in an IL-1-, IL-17-, and G-CSF-dependent manner.

PubMed

Capitano, Maegan L; Nemeth, Michael J; Mace, Thomas A; Salisbury-Ruf, Christi; Segal, Brahm H; McCarthy, Philip L; Repasky, Elizabeth A

2012-09-27

Neutropenia is a common side effect of cytotoxic chemotherapy and radiation, increasing the risk of infection in these patients. Here we examined the impact of body temperature on neutrophil recovery in the blood and bone marrow after total body irradiation (TBI). Mice were exposed to either 3 or 6 Gy TBI followed by a mild heat treatment that temporarily raised core body temperature to approximately 39.5°C. Neutrophil recovery was then compared with control mice that received either TBI alone heat treatment alone. Mice that received both TBI and heat treatment exhibited a significant increase in the rate of neutrophil recovery in the blood and an increase in the number of marrow hematopoietic stem cells and neutrophil progenitors compared with that seen in mice that received either TBI or heat alone. The combination treatment also increased G-CSF concentrations in the serum, bone marrow, and intestinal tissue and IL-17, IL-1β, and IL-1α concentrations in the intestinal tissue after TBI. Neutralizing G-CSF or inhibiting IL-17 or IL-1 signaling significantly blocked the thermally mediated increase in neutrophil numbers. These findings suggest that a physiologically relevant increase in body temperature can accelerate recovery from neutropenia after TBI through a G-CSF-, IL-17-, and IL-1-dependent mechanism.

Elevating body temperature enhances hematopoiesis and neutrophil recovery after total body irradiation in an IL-1–, IL-17–, and G-CSF–dependent manner

PubMed Central

Capitano, Maegan L.; Nemeth, Michael J.; Mace, Thomas A.; Salisbury-Ruf, Christi; Segal, Brahm H.; McCarthy, Philip L.

2012-01-01

Neutropenia is a common side effect of cytotoxic chemotherapy and radiation, increasing the risk of infection in these patients. Here we examined the impact of body temperature on neutrophil recovery in the blood and bone marrow after total body irradiation (TBI). Mice were exposed to either 3 or 6 Gy TBI followed by a mild heat treatment that temporarily raised core body temperature to approximately 39.5°C. Neutrophil recovery was then compared with control mice that received either TBI alone heat treatment alone. Mice that received both TBI and heat treatment exhibited a significant increase in the rate of neutrophil recovery in the blood and an increase in the number of marrow hematopoietic stem cells and neutrophil progenitors compared with that seen in mice that received either TBI or heat alone. The combination treatment also increased G-CSF concentrations in the serum, bone marrow, and intestinal tissue and IL-17, IL-1β, and IL-1α concentrations in the intestinal tissue after TBI. Neutralizing G-CSF or inhibiting IL-17 or IL-1 signaling significantly blocked the thermally mediated increase in neutrophil numbers. These findings suggest that a physiologically relevant increase in body temperature can accelerate recovery from neutropenia after TBI through a G-CSF–, IL-17–, and IL-1–dependent mechanism. PMID:22806894

Sensing the heat with TRPM3.

PubMed

Vriens, Joris; Voets, Thomas

2018-05-01

Heat sensation, the ability to detect warm and noxious temperatures, is an ancient and indispensable sensory process. Noxious temperatures can have detrimental effects on the physiology and integrity of cells, and therefore, the detection of environmental hot temperatures is absolutely crucial for survival. Temperature-sensitive ion channels, which conduct ions in a highly temperature-dependent manner, have been put forward as molecular thermometers expressed at the endings of sensory neurons. In particular, several temperature-sensitive members of the transient receptor potential (TRP) superfamily of ion channels have been identified, and a multitude of in vivo studies have shown that the capsaicin-sensitive TRPV1 channel plays a key role as a noxious heat sensor. However, Trpv1-deficient mice display a residual heat sensitivity suggesting the existence of additional heat sensor(s). In this chapter, we provide evidence for the role of the non-selective calcium-permeable TRPM3 ion channel as an additional heat sensor that acts independently of TRPV1, and give an update of the modulation of this channel by various molecular mechanisms. Finally, we compare antagonists of TRPM3 to specific blockers of TRPV1 as potential analgesic drugs to treat pathological pain.

Characterization of phycocyanin from Spirulina fusiformis and its thermal stability

NASA Astrophysics Data System (ADS)

Munawaroh, H. S. H.; Darojatun, K.; Gumilar, G. G.; Aisyah, S.; Wulandari, A. P.

2018-05-01

Microalgae have some pigments which are potential to be used as functional colorant for foods and cosmetics industries. Here, Spirulina fusiformis is one of the major sources of a blue pigment phycocyanin which has commercial and biotechnological value for biomedical research, as well as a natural colorant for food and cosmetic industries. This study aims at investigating the characteristic of isolated C-phycocyanin from Spirulina fusiformis and its stability under different temperature. A food grade phycocyanin with purity of 2.0 (A620/A280) was obtained successfully from Spirulina fusiformis cultured in seawater-based modified medium and purified by ammonium sulfate precipitation. No significant changes were observed in the spectrum absorbance of C-phycocyanin at temperature up to 60°C over 30 minutes of incubation, and was observed to significantly denaturation at 70°C and higher temperature. Incubation of the pigment at relatively high temperature resulted in a decrease in the spectrum intensities of the C-phycocyanin in a temperature-dependent manner. Taken together, our results suggest that the optimal condition for preserving the stability of food grade phycocyanin isolated from Spirulina fusiformis is taking it at low temperature.

Mechanophysical Stimulations of Mucin Secretion in Cultures of Nasal Epithelial Cells

PubMed Central

Even-Tzur Davidovich, Nurit; Kloog, Yoel; Wolf, Michael; Elad, David

2011-01-01

Nasal epithelial cells secret mucins and are exposed in vivo to airflow-induced mechanophysical stresses, including wall shear stress (WSS), temperature, and humidity. In this work, human nasal epithelial cells cultured under air-liquid interface conditions were subjected to fields of airflow-induced oscillatory WSS at different temperature and humidity conditions. Changes in mucin secretion due to WSS were measured and the role of the cytoskeleton in mucin secretion was explored. Mucin secretion significantly increased in response to WSS in a magnitude-dependent manner with respect to static cultures and independently of the airflow temperature and humidity. In static cultures, mucin secretion decreased at high humidity with or without elevation of the temperature with respect to cultures at a comfortable climate. In cultures exposed to WSS, mucin secretion increased at high temperature with respect to cultures at comfortable climate conditions. The polymerization of actin microfilaments was shown to increase mucin secretion under WSS, whereas the dynamics of microtubule polymerization did not affect secretion. In conclusion, the data in this study show that mucin secretion is sensitive to oscillatory WSS as well as high temperature and humidity conditions. PMID:21689518

Low-temperature plasma-induced antiproliferative effects on multi-cellular tumor spheroids

NASA Astrophysics Data System (ADS)

Plewa, Joseph-Marie; Yousfi, Mohammed; Frongia, Céline; Eichwald, Olivier; Ducommun, Bernard; Merbahi, Nofel; Lobjois, Valérie

2014-04-01

Biomedical applications of low-temperature plasmas are of growing interest, especially in the field of plasma-induced anti-tumor effects. The present work is aimed at investigating the regionalized antiproliferative effects of low-temperature plasmas on a multicellular tumor spheroid (MCTS), a model that mimics the 3D organization and regionalization of a microtumor region. We report that a low-temperature plasma jet, using helium flow in open air, inhibits HCT116 colon carcinoma MCTS growth in a dose-dependent manner. This growth inhibition is associated with the loss of Ki67, and the regionalized accumulation of DNA damage detected by histone H2AX phosphorylation. This regionalized genotoxic effect leads to massive cell death and loss of the MCTS proliferative region. The use of reactive oxygen species (ROS), scavenger N-acetyl cysteine (NAC) and plasma-conditioned media demonstrate that the ROS generated in the media after exposure to low-temperature plasma play a major role in these observed effects. These findings strengthen the interest in the use of MCTS for the evaluation of antiproliferative strategies, and open new perspectives for studies dedicated to demonstrate the potential of low-temperature plasma in cancer therapy.

Nonlinear viscoelastic characterization of polymer materials using a dynamic-mechanical methodology

NASA Technical Reports Server (NTRS)

Strganac, Thomas W.; Payne, Debbie Flowers; Biskup, Bruce A.; Letton, Alan

1995-01-01

Polymer materials retrieved from LDEF exhibit nonlinear constitutive behavior; thus the authors present a method to characterize nonlinear viscoelastic behavior using measurements from dynamic (oscillatory) mechanical tests. Frequency-derived measurements are transformed into time-domain properties providing the capability to predict long term material performance without a lengthy experimentation program. Results are presented for thin-film high-performance polymer materials used in the fabrication of high-altitude scientific balloons. Predictions based upon a linear test and analysis approach are shown to deteriorate for moderate to high stress levels expected for extended applications. Tests verify that nonlinear viscoelastic response is induced by large stresses. Hence, an approach is developed in which the stress-dependent behavior is examined in a manner analogous to modeling temperature-dependent behavior with time-temperature correspondence and superposition principles. The development leads to time-stress correspondence and superposition of measurements obtained through dynamic mechanical tests. Predictions of material behavior using measurements based upon linear and nonlinear approaches are compared with experimental results obtained from traditional creep tests. Excellent agreement is shown for the nonlinear model.

Effect of Doping on Surface Reactivity and Conduction Mechanism in Sm-doped CeO2 Thin Films

DOE PAGES

Yang, Nan; Belianinov, Alex; Strelcov, Evgheni; ...

2014-11-21

Scanning probe microscopy measurements show irreversible surface electrochemistry in Sm-doped CeO2 thin films, which depends on humidity, temperature and doping concentration. A systematic study by electrochemical strain microscopy (ESM) in samples with two different Sm content and in several working conditions allows disclosing the microscopic mechanism underlying the difference in water adsorption and splitting with subsequent proton liberation. We measure the behavior of the hysteresis loops by changing temperature and humidity, both in standard ESM configuration and using the first order reversal curve (FORC) method. Complementing our study with spectroscopic measurements by hard x-ray photoemission spectroscopy we find that watermore » incorporation is favored until the doping with Sm is too high to allow the presence of Ce3+. The influence of doping on the surface reactivity and conduction mechanism clearly emerges from all of our experimental results. We find that at lower Sm concentration proton conduction is prevalent, featured by lower activation energy and higher mobility. Defect concentrations determine the type of the prevalent charge carrier in a doping dependent manner.« less

Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine

PubMed Central

Yang, Jiang-Ning; Chen, Jiang-Fan; Fredholm, Bertil B.

2009-01-01

Heart rate (HR), body temperature (Temp), locomotor activity (LA), and oxygen consumption (O2C) were studied in awake mice lacking one or both of the adenosine A1 or A2A receptors (A1R or A2AR, respectively) using telemetry and respirometry, before and after caffeine administration. All parameters were lower during day than night and higher in females than males. When compared with wild-type (WT) littermates, HR was higher in male A1R knockout (A1RKO) mice but lower in A2ARKO mice and intermediate in A1-A2AR double KO mice. A single dose of an unselective β-blocker (timolol; 1 mg/kg) abolished the HR differences between these genotypes. Deletion of A1Rs had little effect on Temp, whereas deletion of A2ARs increased it in females and decreased it in males. A1-A2ARKO mice had lower Temp than WT mice. LA was unaltered in A1RKO mice and lower in A2ARKO and A1-A2ARKO mice than in WT mice. Caffeine injection increased LA but only in mice expressing A2AR. Caffeine ingestion also increased LA in an A2AR-dependent manner in male mice. Caffeine ingestion significantly increased O2C in WT mice, but less in the different KO mice. Injection of 30 mg/kg caffeine decreased Temp, especially in KO mice, and hence in a manner unrelated to A1R or A2AR blockade. Selective A2B antagonism had little or no effect. Thus A1R and A2AR influence HR, Temp, LA, and O2C in mice in a sex-dependent manner, indicating effects of endogenous adenosine. The A2AR plays an important role in the modulation of O2C and LA by acute and chronic caffeine administration. There is also evidence for effects of higher doses of caffeine being independent of both A1R and A2AR. PMID:19218506

A two phase Mach number description of the equilibrium flow of nitrogen in ducts

NASA Technical Reports Server (NTRS)

Bursik, J. W.; Hall, R. M.; Adcock, J. B.

1979-01-01

Some additional thermodynamic properties of the usual two-phase form which is linear in the moisture fraction are derived which are useful in the analysis of many kinds of duct flow. The method used is based on knowledge of the vapor pressure and Gibbs function as functions of temperature. With these, additional two-phase functions linear in moisture fraction are generated, which ultimately reveal that the squared ratio of mixture specific volume to mixture sound speed depends on liquid mass fraction and temperature in the same manner as do many weighted mean two-phase properties. This leads to a simple method of calculating two-phase Mach numbers for various duct flows. The matching of one- and two-phase flows at a saturated vapor point with discontinuous Mach number is also discussed.

Effects of Δ9-THC and cannabidiol vapor inhalation in male and female rats.

PubMed

Javadi-Paydar, Mehrak; Nguyen, Jacques D; Kerr, Tony M; Grant, Yanabel; Vandewater, Sophia A; Cole, Maury; Taffe, Michael A

2018-06-16

Previous studies report sex differences in some, but not all, responses to cannabinoids in rats. The majority of studies use parenteral injection; however, most human use is via smoke inhalation and, increasingly, vapor inhalation. To compare thermoregulatory and locomotor responses to inhaled ∆ 9 -tetrahydrocannabinol (THC), cannabidiol (CBD), and their combination using an e-cigarette-based model in male and female rats METHODS: Male and female Wistar rats were implanted with radiotelemetry devices for the assessment of body temperature and locomotor activity. Animals were then exposed to THC or CBD vapor using a propylene glycol (PG) vehicle. THC dose was adjusted via the concentration in the vehicle (12.5-200 mg/mL) and the CBD (100, 400 mg/mL) dose was also adjusted by varying the inhalation duration (10-40 min). Anti-nociception was evaluated using a tail-withdrawal assay following vapor inhalation. Plasma samples obtained following inhalation in different groups of rats were compared for THC content. THC inhalation reduced body temperature and increased tail-withdrawal latency in both sexes equivalently and in a concentration-dependent manner. Female temperature, activity, and tail-withdrawal responses to THC did not differ between estrus and diestrus. CBD inhalation alone induced modest hypothermia and suppressed locomotor activity in both males and females. Co-administration of THC with CBD, in a 1:4 ratio, significantly decreased temperature and activity in an approximately additive manner and to similar extent in each sex. Plasma THC varied with the concentration in the PG vehicle but did not differ across rat sex. In summary, the inhalation of THC or CBD, alone and in combination, produces approximately equivalent effects in male and female rats. This confirms the efficacy of the e-cigarette-based method of THC delivery in female rats.

The Anti-inflammatory Drug Indomethacin Alters Nanoclustering in Synthetic and Cell Plasma Membranes*

PubMed Central

Zhou, Yong; Plowman, Sarah J.; Lichtenberger, Lenard M.; Hancock, John F.

2010-01-01

The nonsteroidal anti-inflammatory drug indomethacin exhibits diverse biological effects, many of which have no clear molecular mechanism. Membrane-bound receptors and enzymes are sensitive to their phospholipid microenvironment. Amphipathic indomethacin could therefore potentially modulate cell signaling by changing membrane properties. Here we examined the effect of indomethacin on membrane lateral heterogeneity. Fluorescence lifetime imaging of cells expressing lipid-anchored probes revealed that treatment of BHK cells with therapeutic levels of indomethacin enhances cholesterol-dependent nanoclustering, but not cholesterol-independent nanoclustering. Immuno-electron microscopy and quantitative spatial mapping of intact plasma membrane sheets similarly showed a selective effect of indomethacin on promoting cholesterol-dependent, but not cholesterol-independent, nanoclustering. To further evaluate the biophysical effects of indomethacin, we measured fluorescence polarization of the phase-sensitive probe Laurdan and FRET between phase-partitioning probes in model bilayers. Therapeutic levels of indomethacin enhanced phase seperation in DPPC/DOPC/Chol (1:1:1) and DPPC/Chol membranes in a temperature-dependent manner, but had minimal effect on the phase behavior of pure DOPC at any temperature. Taken together, the imaging results on intact epithelial cells and the biophysical assays of model membranes suggest that indomethacin can enhance phase separation and stabilize cholesterol-dependent nanoclusters in biological membranes. These effects on membrane lateral heterogeneity may have significant consequences for cell signaling cascades that are assembled on the plasma membrane. PMID:20826816

Activation of TRPV2 negatively regulates the differentiation of mouse brown adipocytes.

PubMed

Sun, Wuping; Uchida, Kunitoshi; Takahashi, Nobuyuki; Iwata, Yuko; Wakabayashi, Shigeo; Goto, Tsuyoshi; Kawada, Teruo; Tominaga, Makoto

2016-09-01

Transient receptor potential vanilloid 2 (TRPV2) acts as a Ca(2+)-permeable non-selective cation channel that has been reported to be sensitive to temperature, mechanical force, and some chemicals. We recently showed that TRPV2 is critical for maintenance of the thermogenic function of brown adipose tissue in mice. However, the involvement of TRPV2 in the differentiation of brown adipocytes remains unexplored. We found that the expression of TRPV2 was dramatically increased during the differentiation of brown adipocytes. Non-selective TRPV2 agonists (2-aminoethoxydiphenyl borate and lysophosphatidylcholine) inhibited the differentiation of brown adipocytes in a dose-dependent manner during the early stage of differentiation of brown adipocytes. The inhibition was rescued by a TRPV2-selective antagonist, SKF96365 (SKF). Mechanical force, which activates TRPV2, also inhibited the differentiation of brown adipocytes in a strength-dependent manner, and the effect was reversed by SKF. In addition, the inhibition of adipocyte differentiation by either TRPV2 ligand or mechanical stimulation was significantly smaller in the cells from TRPV2KO mice. Moreover, calcineurin inhibitors, cyclosporine A and FK506, partially reversed TRPV2 activation-induced inhibition of brown adipocyte differentiation. Thus, we conclude that TRPV2 might be involved in the modulation of brown adipocyte differentiation partially via a calcineurin pathway.

Metal organic framework Cu9Cl2(cpa)6 as tunable molecular magnet

NASA Astrophysics Data System (ADS)

Hamilton, Heather S. C.; Farmer, William M.; Skinner, Samuel F.; ter Haar, Leonard W.

2018-05-01

Chemical modifications of the magnetic metal organic framework (MOF) Cu9X2(cpa)6.42H2O (X = F, Cl, Br; cpa = anion of 2-carboxypentonicacid) have been investigated as a means of modifying, in a tunable manner, the magnetism of this 2-D material best described as a triangles-in-triangles (TIT) or triangulated-Kagomé-latttice (TKL). Since numerous theoretical studies have already attempted to describe the enigmatic ground state of this Heisenberg lattice, tunable chemical modifications should provide an excellent opportunity to expand this class of materials for studies concerning fundamental physics of frustrated spins, and applications such as adiabatic demagnetization refrigeration (ADR) that depend on the magnetocaloric effect (MCE). The chemical modification investigated is the intercalation of d- and f-orbital ions into the voids of the framework (channels of nearly 20 Å diameter). Magnetic measurements in the temperature range 1.8 - 300 K confirm signature features of TKL magnetism in intercalated samples persist, specifically: i) large negative Weiss constant (θCW); ii) absence of a phase transition down to 1.8 K; iii) minimum in χMT; iv) low temperature χMT values increasingly divergent at low fields indicating net ferromagnetic correlations; and, v) increasing field dependence of magnetization at low temperatures suggestive of intermediate plateaus, or ferrimagnetism, not saturation.

EUCLIA—Exploring the UV/Optical Continuum Lag in Active Galactic Nuclei. I. A Model without Light Echoing

NASA Astrophysics Data System (ADS)

Cai, Zhen-Yi; Wang, Jun-Xian; Zhu, Fei-Fan; Sun, Mou-Yuan; Gu, Wei-Min; Cao, Xin-Wu; Yuan, Feng

2018-03-01

The tight interband correlation and the lag–wavelength relation among UV/optical continua of active galactic nuclei have been firmly established. They are usually understood within the widespread reprocessing scenario; however, the implied interband lags are generally too small. Furthermore, it is challenged by new evidence, such as that the X-ray reprocessing yields too much high-frequency UV/optical variation and that it fails to reproduce the observed timescale-dependent color variations among the Swift light curves of NGC 5548. In a different manner, we demonstrate that an upgraded inhomogeneous accretion disk model, whose local independent temperature fluctuations are subject to a speculated common large-scale temperature fluctuation, can intrinsically generate the tight interband correlation and lag across the UV/optical and be in nice agreement with several observational properties of NGC 5548, including the timescale-dependent color variation. The emergent lag is a result of the differential regression capability of local temperature fluctuations when responding to the large-scale fluctuation. An average speed of propagations as large as ≳15% of the speed of light may be required by this common fluctuation. Several potential physical mechanisms for such propagations are discussed. Our interesting phenomenological scenario may shed new light on comprehending the UV/optical continuum variations of active galactic nuclei.

Development of a novel method to determine the concentration of heavy metal cations: application of the specific interaction between heavy metal cation and mismatch DNA base pair.

PubMed

Kozasa, Tetsuo; Miyakawa, Yukako; Fukushi, Miyako; Ono, Akira; Torigoe, Hidetaka

2009-01-01

We have already found that Hg(II) cation specifically binds to T:T mismatch base pair in heteroduplex DNA, which increases the melting temperature of heteroduplex DNA involving T:T mismatch base pair by about 4 degrees C. We have also found that Ag(I) cation specifically binds to C:C mismatch base pair in heteroduplex DNA, which increases the melting temperature of heteroduplex DNA involving C:C mismatch base pair by about 4 degrees C. Using the specific interaction, we developed a novel sensor to determine the concentration of each of Hg(II) and Ag(I) cation. The sensor is composed of a dye-labelled T-rich or C-rich DNA oligonucleotide, F2T6W2D: 5'-Fam-T(2)CT(2)CT(2)C(4)T(2)GT(2)GT(2)-Dabcyl-3' or F2C6W2D: 5'-Fam-C(2)TC(2)TC(2)T(4)C(2)AC(2)AC(2)-Dabcyl-3', where 6-carboxyfluorescein (Fam) is a fluorophore and Dabcyl is a quencher. The addition of Hg(II) cation decreased the intensity of Fam emission of F2T6W2D at 520 nm in a concentration-dependent manner. Also, the addition of Ag(I) cation decreased the intensity of Fam emission of F2C6W2D at 520 nm in a concentration-dependent manner. We conclude that, using the novel sensor developed in this study, the concentration of each of Hg(II) and Ag(I) cation can be determined from the intensity of Fam emission at 520 nm.

Influence of chemistry, interfacial width, and non-isothermal conditions on spatially heterogeneous activated relaxation and elasticity in glass-forming free standing films

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

Mirigian, Stephen; Schweizer, Kenneth S.

Here, we employ the Elastically Collective Nonlinear Langevin Equation (ECNLE) theory of activated relaxation to study several questions in free standing thin films of glass-forming molecular and polymer liquids. The influence of non-universal chemical aspects on dynamical confinement effects is found to be relatively weak, but with the caveat that for the systems examined, the bulk ECNLE polymer theory does not predict widely varying fragilities. Allowing the film model to have a realistic vapor interfacial width significantly enhances the reduction of the film-averaged glass transition temperature, T g, in a manner that depends on whether a dynamic or pseudo-thermodynamic averagingmore » of the spatial mobility gradient is adopted. The nature of film thickness effects on the spatial profiles of the alpha relaxation time and elastic modulus is studied under non-isothermal conditions and contrasted with the corresponding isothermal behavior. Modest differences are found if a film-thickness dependent T g is defined in a dynamical manner. But, adopting a pseudo-thermodynamic measure of T g leads to a qualitatively new form of the alpha relaxation time gradient where highly mobile layers near the film surface coexist with strongly vitrified regions in the film interior. Consequently, the film-averaged shear modulus can increase with decreasing film thickness, despite the T g reduction and presence of a mobile surface layer. Such a behavior stands in qualitative contrast to the predicted mechanical softening under isothermal conditions. Spatial gradients of the elastic modulus are studied as a function of temperature, film thickness, probing frequency, and experimental protocol, and a rich behavior is found.« less

Influence of chemistry, interfacial width, and non-isothermal conditions on spatially heterogeneous activated relaxation and elasticity in glass-forming free standing films

DOE PAGES

Mirigian, Stephen; Schweizer, Kenneth S.

2017-02-02

Here, we employ the Elastically Collective Nonlinear Langevin Equation (ECNLE) theory of activated relaxation to study several questions in free standing thin films of glass-forming molecular and polymer liquids. The influence of non-universal chemical aspects on dynamical confinement effects is found to be relatively weak, but with the caveat that for the systems examined, the bulk ECNLE polymer theory does not predict widely varying fragilities. Allowing the film model to have a realistic vapor interfacial width significantly enhances the reduction of the film-averaged glass transition temperature, T g, in a manner that depends on whether a dynamic or pseudo-thermodynamic averagingmore » of the spatial mobility gradient is adopted. The nature of film thickness effects on the spatial profiles of the alpha relaxation time and elastic modulus is studied under non-isothermal conditions and contrasted with the corresponding isothermal behavior. Modest differences are found if a film-thickness dependent T g is defined in a dynamical manner. But, adopting a pseudo-thermodynamic measure of T g leads to a qualitatively new form of the alpha relaxation time gradient where highly mobile layers near the film surface coexist with strongly vitrified regions in the film interior. Consequently, the film-averaged shear modulus can increase with decreasing film thickness, despite the T g reduction and presence of a mobile surface layer. Such a behavior stands in qualitative contrast to the predicted mechanical softening under isothermal conditions. Spatial gradients of the elastic modulus are studied as a function of temperature, film thickness, probing frequency, and experimental protocol, and a rich behavior is found.« less

Superconductivity in an almost localized Fermi liquid of quasiparticles with spin-dependent masses and effective-field induced by electron correlations

NASA Astrophysics Data System (ADS)

Kaczmarczyk, Jan; Spałek, Jozef

2009-06-01

Paired state of nonstandard quasiparticles is analyzed in detail in two model situations. Namely, we consider the Cooper-pair bound state and the condensed phase of an almost localized Fermi liquid composed of quasiparticles in a narrow band with the spin-dependent masses and an effective field, both introduced earlier and induced by strong electronic correlations. Each of these novel characteristics is calculated in a self-consistent manner. We analyze the bound states as a function of Cooper-pair momentum |Q| in applied magnetic field in the strongly Pauli limiting case (i.e., when the orbital effects of applied magnetic field are disregarded). The spin-direction dependence of the effective mass makes the quasiparticles comprising Cooper-pair spin distinguishable in the quantum-mechanical sense, whereas the condensed gas of pairs may still be regarded as composed of identical entities. The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) condensed phase of moving pairs is by far more robust in the applied field for the case with spin-dependent masses than in the situation with equal masses of quasiparticles. Relative stability of the Bardeen-Cooper-Schrieffer vs FFLO phase is analyzed in detail on temperature-applied field plane. Although our calculations are carried out for a model situation, we can conclude that the spin-dependent masses should play an important role in stabilizing high-field low-temperature unconventional superconducting phases (FFLO, for instance) in systems such as CeCoIn5 , organic metals, and possibly others.

Performance and emission characteristics of swirl-can combustors to near-stoichiometric fuel-air ratio

NASA Technical Reports Server (NTRS)

Diehl, L. A.; Trout, A. M.

1976-01-01

Emissions and performance characteristics were determined for two full annular swirl-can combustors operated to near stoichiometric fuel-air ratio. Test condition variations were as follows: combustor inlet-air temperatures, 589, 756, 839, and 894 K; reference velocities, 24 to 37 meters per second; inlet pressure, 62 newtons per square centimeter; and fuel-air ratios, 0.015 to 0.065. The combustor average exit temperature and combustor efficiency were calculated from the combustor exhaust gas composition. For fuel-air ratios greater than 0.04, the combustion efficiency decreased with increasing fuel-air ratios in a near-linear manner. Increasing the combustor inlet air temperature tended to offset this decrease. Maximum oxides of nitrogen emission indices occurred at intermediate fuel-air ratios and were dependent on combustor design. Carbon monoxide levels were extremely high and were the primary cause of poor combustion efficiency at the higher fuel-air ratios. Unburned hydrocarbons were low for all test conditions. For high fuel-air ratios SAE smoke numbers greater than 25 were produced, except at the highest inlet-air temperatures.

Role of thyroidal and testicular hormones in regulation of tissue respiration in male air-breathing fish, Clarias batrachus (Linn.).

PubMed

Lynshiang, D S; Gupta, B B

2000-07-01

In vivo and in vitro effects of thyroidal hormones (MIT, DIT, T3, T4), propyl thiouracil (PTU), testosterone and cyproterone acetate were studied on the rate of tissue (liver, muscle, kidney and brain) respiration of adult male C. batrachus during winter and summer/rainy seasons. Monoiodotyrosine (MIT) and diiodothyrosine (DIT) increased the respiratory rate in a dose-dependent and temperature-independent manner. Triiodothyronine (T3) and thyroxine (T4) stimulated tissue respiration during summer/rainy months but not during winter. PTU decreased tissue respiration during summer/rainy season and also at simulated low temperature. Testosterone invariably stimulated the rate of respiration of the tissues, while in vivo treatment with cyproterone acetate significantly decreased the metabolic rate of all the tissues. The findings suggest that in C. batrachus MIT and DIT may be more important than T3 and T4 at low temperature, endogenous thyroid hormones are involved indirectly in energy metabolism even during winter/at low temperature and testicular hormones are actively involved in the respiration.

Cardiorespiratory performance during prolonged swimming tests with salmonids: a perspective on temperature effects and potential analytical pitfalls.

PubMed

Farrell, A P

2007-11-29

A prolonged swimming trial is the most common approach in studying steady-state changes in oxygen uptake, cardiac output and tissue oxygen extraction as a function of swimming speed in salmonids. The data generated by these sorts of studies are used here to support the idea that a maximum oxygen uptake is reached during a critical swimming speed test. Maximum oxygen uptake has a temperature optimum. Potential explanations are advanced to explain why maximum aerobic performance falls off at high temperature. The valuable information provided by critical swimming tests can be confounded by non-steady-state swimming behaviours, which typically occur with increasing frequency as salmonids approach fatigue. Two major concerns are noted. Foremost, measurements of oxygen uptake during swimming can considerably underestimate the true cost of transport near critical swimming speed, apparently in a temperature-dependent manner. Second, based on a comparison with voluntary swimming ascents in a raceway, forced swimming trials in a swim tunnel respirometer may underestimate critical swimming speed, possibly because fish in a swim tunnel respirometer are unable to sustain a ground speed.

Infralimbic cortex controls core body temperature in a histamine dependent manner.

PubMed

Riveros, M E; Perdomo, G; Torrealba, F

2014-04-10

An increase in body temperature accelerates biochemical reactions and behavioral and physiological responses. A mechanism to actively increase body temperature would be beneficial during motivated behaviors. The prefrontal cortex is implicated in organizing motivated behavior; the infralimbic cortex, a subregion of the medial prefrontal cortex, has the necessary connectivity to serve the role of initiating such thermogenic mechanism at the beginning of the appetitive phase of motivated behavior; further, this cortex is active during motivated behavior and its disinhibition produces a marked behavioral and vegetative arousal increase, together with increases in histamine levels. We wanted to explore if this arousal was related to histaminergic activation after pharmacological infralimbic disinhibition and during the appetitive phase of motivated behavior. We measured core temperature and motor activity in response to picrotoxin injection in the infralimbic cortex, as well as during food-related appetitive behavior, evoked by enticing hungry rats with food. Pretreatment with the H1 receptor antagonist pyrilamine decreased thermal response to picrotoxin and enticement and completely blunted motor response to enticement. Motor and temperature responses to enticement were also completely abolished by infralimbic cortex inhibition with muscimol. To assess if this histamine dependent temperature increase was produced by an active sympathetic mediated thermogenic mechanism or was just a consequence of increased locomotor activity, we injected propranolol (i.p.), a β adrenergic receptor blocker, before picrotoxin injection into the infralimbic cortex. Propranolol reduced the temperature increase without affecting locomotor activity. Altogether, these results suggest that infralimbic activation is necessary for appetitive behavior by inducing a motor and a vegetative arousal increase mediated by central histamine. Copyright © 2014 Elsevier Inc. All rights reserved.

Warmer weather as a risk factor for hospitalisations due to urinary tract infections.

PubMed

Simmering, J E; Cavanaugh, J E; Polgreen, L A; Polgreen, P M

2018-02-01

The incidence of urinary tract infections (UTIs) is seasonal, and this seasonality may be explained by changes in weather, specifically, temperature. Using data from the Nationwide Inpatient Sample, we identified the geographic location for 581 813 hospital admissions with the primary diagnosis of a UTI and 56 630 773 non-UTI hospitalisations in the United States. Next, we used data from the National Climatic Data Center to estimate the monthly average temperature for each location. Using a case-control design, we modelled the odds of a hospital admission having a primary diagnosis of UTI as a function of demographics, payer, location, patient severity, admission month, year and the average temperature for the admission month. We found, after controlling for patient factors and month of admission, the odds of a UTI diagnosis increased with higher temperatures in a dose-dependent manner. For example, relative to months with average temperatures of 5-7.5 °C, an admission in a month with an average temperature of 27.5-30 °C has 20% higher odds of a primary diagnosis of UTI. However, in months with extremely high average temperatures (above 30 °C), the odds of a UTI admissions decrease, perhaps due to changes in behaviour. Thus, at a population level, UTI-related hospitalisations are associated with warmer weather.

Functional Analysis of a Type-I Ribosome Inactivating Protein Balsamin from Momordica balsamina with Anti-Microbial and DNase Activity.

PubMed

Ajji, Parminder Kaur; Walder, Ken; Puri, Munish

2016-09-01

Ribosome inactivating proteins (RIPs) have received considerable attention in biomedical research because of their unique activities towards tumor and virus-infected cells. We extracted balsamin, a type-I RIP, from Momordica balsamina. In the present study, a detailed investigation on DNase activity, antioxidant capacity and antibacterial activity was conducted using purified balsamin. DNase-like activity of balsamin towards plasmid DNA was pH, incubation time and temperature dependent. Moreover, the presence of Mg(2+) (10-50 mM) influenced the DNA cleavage activity. Balsamin also demonstrated reducing power and a capacity to scavenge free radicals in a dose dependent manner. Furthermore, the protein exhibited antibacterial activity against Staphylococcus aureus, Salmonella enterica, Staphylococcus epidermidis and Escherichia coli, which suggests potential utility of balsamin as a nutraceutical.

Effects of Temperature on Polymer/Carbon Chemical Sensors

NASA Technical Reports Server (NTRS)

Manfireda, Allison; Lara, Liana; Homer, Margie; Yen, Shiao-Pin; Kisor, Adam; Ryan, Margaret; Zhou, Hanying; Shevade, Abhijit; James, Lim; Manatt, Kenneth

2009-01-01

Experiments were conducted on the effects of temperature, polymer molecular weight, and carbon loading on the electrical resistances of polymer/carbon-black composite films. The experiment were performed in a continuing effort to develop such films as part of the JPL Electronic Nose (ENose), that would be used to detect, identify, and quantify parts-per-million (ppm) concentration levels of airborne chemicals in the space shuttle/space station environments. The polymers used in this study were three formulations of poly(ethylene oxide) [PEO] that had molecular weights of 20 kilodaltons, 600 kilodaltons, and 1 megadalton, respectively. The results of one set of experiments showed a correlation between the polymer molecular weight and the percolation threshold. In a second set of experiments, differences among the temperature dependences of resistance were observed for different carbon loadings; these differences could be explained by a change in the conduction mechanism. In a third set of experiments, the responses of six different polymer/carbon composite sensors to three analytes (water vapor, methanol, methane) were measured as a function of temperature (28 to 36 C). For a given concentration of each analyte, the response of each sensor decreased with increasing temperature, in a manner different from those of the other sensors.

Parametric Methods for Determining the Characteristics of Long-Term Metal Strength

NASA Astrophysics Data System (ADS)

Nikitin, V. I.; Rybnikov, A. I.

2018-06-01

A large number of parametric methods were proposed to calculate the characteristics of the long-term strength of metals. All of them are based on the fact that temperature and time are mutually compensating factors in the processes of metal degradation at high temperature under the action of a constant stress. The analysis of the well-known Larson-Miller, Dorn-Shcherby, Menson-Haferd, Graham-Wallace, and Trunin parametric equations is performed. The widely used Larson-Miller parameter was subjected to a detailed analysis. The application of this parameter to the calculation of ultimate long-term strength for steels and alloys is substantiated provided that the laws of exponential dependence on temperature and power dependence on strength for the heat resistance are observed. It is established that the coefficient C in the Larson- Miller equation is a characteristic of the heat resistance and is different for each material. Therefore, the use of a universal constant C = 20 in parametric calculations, as well as an a priori presetting of numerical C values for each individual group of materials, is unacceptable. It is shown in what manner it is possible to determine an exact value of coefficient C for any material of interest as well as to obtain coefficient C depending on stress in case such a dependence is manifested. At present, the calculation of long-term strength characteristics can be performed to a sufficient accuracy using Larson-Miller's parameter and its refinements described therein as well as on the condition that a linear law in logσ- P dependence is observed and calculations in the interpolation range is performed. The use of the presented recommendations makes it possible to obtain a linear parametric logσ- P dependence, which makes it possible to determine to a sufficient accuracy the values of ultimate long-term strength for different materials.

Fracture Properties of Polystyrene Aggregate Concrete after Exposure to High Temperatures

PubMed Central

Tang, Waiching; Cui, Hongzhi; Tahmasbi, Soheil

2016-01-01

This paper mainly reports an experimental investigation on the residual mechanical and fracture properties of polystyrene aggregate concrete (PAC) after exposure to high temperatures up to 800 degrees Celsius. The fracture properties namely, the critical stress intensity factor (KICS), the critical crack tip opening displacement (CTODC) for the Two-Parameter Model, and the fracture energy (GF) for the Fictitious Crack Model were examined using the three-point bending notched beam test, according to the RILEM recommendations. The effects of polystyrene aggregate (PA) content and temperature levels on the fracture and mechanical properties of concrete were investigated. The results showed that the mechanical properties of PAC significantly decreased with increase in temperature level and the extent of which depended on the PA content in the mixture. However, at a very high temperature of 800 °C, all samples showed 80 percent reduction in modulus of elasticity compared to room temperature, regardless of the level of PA content. Fracture properties of control concrete (C) and PAC were influenced by temperature in a similar manner. Increasing temperature from 25 °C to 500 °C caused almost 50% reduction of the fracture energy for all samples while 30% increase in fracture energy was occurred when the temperature increased from 500 °C to 800 °C. It was found that adding more PA content in the mixture lead to a more ductile behaviour of concrete. PMID:28773752

Pressure-Induced Phase Transitions in GeTe-Rich Ge-Sb-Te Alloys across the Rhombohedral-to-Cubic Transitions.

PubMed

Krbal, Milos; Bartak, Jaroslav; Kolar, Jakub; Prytuliak, Anastasiia; Kolobov, Alexander V; Fons, Paul; Bezacier, Lucile; Hanfland, Michael; Tominaga, Junji

2017-07-17

We demonstrate that pressure-induced amorphization in Ge-Sb-Te alloys across the ferroelectric-paraelectric transition can be represented as a mixture of coherently distorted rhombohedral Ge 8 Sb 2 Te 11 and randomly distorted cubic Ge 4 Sb 2 Te 7 and high-temperature Ge 8 Sb 2 Te 11 phases. While coherent distortion in Ge 8 Sb 2 Te 11 does not prevent the crystalline state from collapsing into its amorphous counterpart in a similar manner to pure GeTe, the pressure-amorphized Ge 8 Sb 2 Te 11 phase begins to revert to the crystalline cubic phase at ∼9 GPa in contrast to Ge 4 Sb 2 Te 7 , which remains amorphous under ambient conditions when gradually decompressed from 40 GPa. Moreover, experimentally, it was observed that pressure-induced amorphization in Ge 8 Sb 2 Te 11 is a temperature-dependent process. Ge 8 Sb 2 Te 11 transforms into the amorphous phase at ∼27.5 and 25.2 GPa at room temperature and 408 K, respectively, and completely amorphizes at 32 GPa at 408 K, while some crystalline texture could be seen until 38 GPa (the last measurement point) at room temperature. To understand the origins of the temperature dependence of the pressure-induced amorphization process, density functional theory calculations were performed for compositions along the (GeTe) x - (Sb 2 Te 3 ) 1-x tie line under large hydrostatic pressures. The calculated results agreed well with the experimental data.

Sweet Polymers: Poly(2-ethyl-2-oxazoline) Glycopolymers by Reductive Amination.

PubMed

Mees, Maarten A; Effenberg, Christiane; Appelhans, Dietmar; Hoogenboom, Richard

2016-12-12

Carbohydrates are important in signaling, energy storage, and metabolism. Depending on their function, carbohydrates can be part of larger structures, such as glycoproteins, glycolipids, or other functionalities (glycoside). To this end, polymers can act as carriers of carbohydrates in so-called glycopolymers, which mimic the multivalent carbohydrate functionalities. We chose a biocompatible poly(2-ethyl-2-oxazoline) (PEtOx) as the basis for making glycopolymers. Via the partial hydrolysis of PEtOx, a copolymer of PEtOx and polyethylenimine (PEI) was obtained; the subsequent reductive amination with the linear forms of glucose and maltose yielded the glycopolymers. The ratios of PEtOx and carbohydrates were varied systematically, and the solution behaviors of the resulting glycoconjugates are discussed. Dynamic light scattering (DLS) revealed that, depending on the carbohydrate ratio, the glycopolymers were either fully water-soluble or formed agglomerates in a temperature-dependent manner. Finally, these polymers were tested for their biological availability by studying their lectin binding ability with Concanavalin A.

Effect of alternating day and night temperature on short day-induced bud set and subsequent bud burst in long days in Norway spruce

PubMed Central

Olsen, Jorunn E.; Lee, YeonKyeong; Junttila, Olavi

2014-01-01

Young seedlings of the conifer Norway spruce exhibit short day (SD)-induced cessation of apical growth and bud set. Although different, constant temperatures under SD are known to modulate timing of bud set and depth of dormancy with development of deeper dormancy under higher compared to lower temperature, systematic studies of effects of alternating day (DT) and night temperatures (NT) are limited. To shed light on this, seedlings of different provenances of Norway spruce were exposed to a wide range of DT-NT combinations during bud development, followed by transfer to forcing conditions of long days (LD) and 18°C, directly or after different periods of chilling. Although no specific effect of alternating DT/NT was found, the results demonstrate that the effects of DT under SD on bud set and subsequent bud break are significantly modified by NT in a complex way. The effects on bud break persisted after chilling. Since time to bud set correlated with the daily mean temperature under SD at DTs of 18 and 21°C, but not a DT of 15°C, time to bud set apparently also depend on the specific DT, implying that the effect of NT depends on the actual DT. Although higher temperature under SD generally results in later bud break after transfer to forcing conditions, the fastest bud flush was observed at intermediate NTs. This might be due to a bud break-hastening chilling effect of intermediate compared to higher temperatures, and delayed bud development to a stage where bud burst can occur, under lower temperatures. Also, time to bud burst in un-chilled seedlings decreased with increasing SD-duration, suggesting that bud development must reach a certain stage before the processes leading to bud burst are initiated. The present results also indicate that low temperature during bud development had a larger effect on the most southern compared to the most northern provenance studied. Decreasing time to bud burst was observed with increasing northern latitude of origin in un-chilled as well as chilled plants. In conclusion, being a highly temperature-dependent process, bud development is strongly delayed by low temperature, and the effects of DT is significantly modified by NT in a complex manner. PMID:25538722

Investigating the synthesis of ligated metal clusters in solution using a flow reactor and electrospray ionization mass spectrometry.

PubMed

Olivares, Astrid; Laskin, Julia; Johnson, Grant E

2014-09-18

The scalable synthesis of ligated subnanometer metal clusters containing an exact number of atoms is of interest due to the highly size-dependent catalytic, electronic, and optical properties of these species. While significant research has been conducted on the batch preparation of clusters through reduction synthesis in solution, the processes of metal complex reduction as well as cluster nucleation, growth, and postreduction etching are still not well understood. Herein, we demonstrate a prototype temperature-controlled flow reactor for qualitatively studying cluster formation in solution at steady-state conditions. Employing this technique, methanol solutions of a chloro(triphenylphosphine)gold precursor, 1,4-bis(diphenylphosphino)butane capping ligand, and borane-tert-butylamine reducing agent were combined in a mixing tee and introduced into a heated capillary with a known length. In this manner, the temperature dependence of the relative abundance of different ionic reactants, intermediates, and products synthesized in real time was characterized qualitatively using online mass spectrometry. A wide distribution of doubly and triply charged cationic gold clusters was observed as well as smaller singly charged organometallic complexes. The results demonstrate that temperature plays a crucial role in determining the relative population of cationic gold clusters and, in general, that higher temperature promotes the formation of doubly charged clusters and singly charged organometallic complexes while reducing the abundance of triply charged species. Moreover, the distribution of clusters observed at elevated temperatures is found to be consistent with that obtained at longer reaction times at room temperature, thereby demonstrating that heating may be used to access cluster distributions characteristic of different stages of batch reduction synthesis in solution.

Singular ferromagnetic susceptibility of the transverse-field Ising antiferromagnet on the triangular lattice

NASA Astrophysics Data System (ADS)

Biswas, Sounak; Damle, Kedar

2018-02-01

A transverse magnetic field Γ is known to induce antiferromagnetic three-sublattice order of the Ising spins σz in the triangular lattice Ising antiferromagnet at low enough temperature. This low-temperature order is known to melt on heating in a two-step manner, with a power-law ordered intermediate temperature phase characterized by power-law correlations at the three-sublattice wave vector Q : <σz(R ⃗) σz(0 ) > ˜cos(Q .R ⃗) /|R⃗| η (T ) with the temperature-dependent power-law exponent η (T )∈(1 /9 ,1 /4 ) . Here, we use a quantum cluster algorithm to study the ferromagnetic easy-axis susceptibility χu(L ) of an L ×L sample in this power-law ordered phase. Our numerical results are consistent with a recent prediction of a singular L dependence χu(L ) ˜L2 -9 η when η (T ) is in the range (1 /9 ,2 /9 ) . This finite-size result implies, via standard scaling arguments, that the ferromagnetic susceptibility χu(B ) to a uniform field B along the easy axis is singular at intermediate temperatures in the small B limit, χu(B ) ˜|B| -4/-18 η 4 -9 η for η (T )∈(1 /9 ,2 /9 ) , although there is no ferromagnetic long-range order in the low temperature state. Additionally we establish similar two-step melting behavior (via a study of the order parameter susceptibility χQ) in the case of the ferrimagnetic three-sublattice ordered phase which is stabilized by ferromagnetic next-neighbor couplings (J2) and confirm that the ferromagnetic susceptibility obeys the predicted singular form in the associated power-law ordered phase.

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

Chlistunoff, Jerzy; Pivovar, Bryan

In this paper, the oxygen reduction reaction (ORR) at the interface between platinum and Nafion 1100 equivalent weight was studied as a function of temperature (20–80 °C), humidity (10–100%), scan rate, the manner in which Nafion film was deposited, and the state of the Pt surface using ultramicroelectrodes employing cyclic voltammetry and chronoamperometry. ORR on smooth electrodes was strongly inhibited under specific conditions dependent on temperature, humidity, and scan rate. From the data presented, we postulate that dynamic changes in the molecular structure of the ionomer at the platinum interface result in differences in ORR voltammetry for films prepared andmore » equilibrated under different conditions. The lack of similar changes for rough, platinized electrodes has been attributed to differences in initial ionomer structure and a higher energy barrier for ionomer restructuring. Finally, these model system studies yield insight into the ionomer-catalyst interface of particular interest for polymer electrolyte fuel cells.« less

Glutathione is a highly efficient thermostabilizer of poliovirus Sabin strains.

PubMed

Abdelnabi, Rana; Delang, Leen; Neyts, Johan

2017-03-07

Glutathione (GSH) is the most abundant thiol peptide in animal cells and has a critical role in antioxidation. GSH was reported to be essential for stabilization of some enteroviruses, including poliovirus (PV), during viral morphogenesis. Here, we explored the potential use of GSH as a thermostabilizer of oral poliomyelitis vaccine (OPV) formulations. GSH significantly protected the three types of PV from heat-inactivation in a concentration-dependent manner. At a GSH concentration of 20mM, nearly complete protection was observed against heating temperatures up to 53°C for 2min.GSH also markedly protected PV1 from heat-inactivation and this up to 6 h at temperatures of 44°C and 46°C and 3 h at 48°C. The fact that GSH is naturally present at high concentration in the human body makes it an efficient candidate stabilizer for OPV formulations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rainbow Rindler metric and Unruh effect

NASA Astrophysics Data System (ADS)

Yadav, Gaurav; Komal, Baby; Majhi, Bibhas Ranjan

2017-11-01

The energy of a particle moving on a space-time, in principle, can affect the background metric. The modifications to it depend on the ratio of energy of the particle and the Planck energy, known as rainbow gravity. Here, we find the explicit expressions for the coordinate transformations from rainbow Minkowski space-time to accelerated frame. The corresponding metric is also obtained which we call as rainbow Rindler metric. So far we are aware of that no body has done it in a concrete manner. Here, this is found from the first principle and hence all the parameters are properly identified. The advantage of this is that the calculated Unruh temperature is compatible with the Hawking temperature of the rainbow black hole horizon, obtained earlier. Since the accelerated frame has several importance in revealing various properties of gravity, we believe that the present result will not only fill that gap, but also help to explore different aspects of rainbow gravity paradigm.

Redox State of Cytochromes in Frozen Yeast Cells Probed by Resonance Raman Spectroscopy.

PubMed

Okotrub, Konstantin A; Surovtsev, Nikolay V

2015-12-01

Cryopreservation is a well-established technique used for the long-term storage of biological materials whose biological activity is effectively stopped under low temperatures (suspended animation). Since most biological methods do not work in a low-temperature frozen environment, the mechanism and details of the depression of cellular activity in the frozen state remain largely uncharacterized. In this work, we propose, to our knowledge, a new approach to study the downregulation of the redox activity of cytochromes b and c in freezing yeast cells in a contactless, label-free manner. Our approach is based on cytochrome photobleaching effects observed in the resonance Raman spectra of live cells. Photoinduced and native redox reactions that contributed to the photobleaching rate were studied over a wide temperature range (from -173 to +25 °C). We found that ice formation influences both the rate of cytochrome redox reactions and the balance between the reduced and oxidized cytochromes. We demonstrate that the temperature dependence of native redox reaction rates can be well described by the thermal activation law with an apparent energy of 32.5 kJ/mol, showing that the redox reaction rate is ∼10(15) times slower at liquid nitrogen temperature than at room temperature. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Naltrexone-sensitive analgesia following exposure of mice to 2450-MHz radiofrequency radiation (RFR)

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

Maillefer, R.H.; Quock, R.M.

1991-03-11

This study was conducted to determine whether exposure to RFR might induce sufficient thermal stress to activate endogenous opioid mechanisms and induce analgesia. Male Swiss Webster mice, 20-25 g, were exposed to 10, 15 or 20 mV/cm{sup 2} RFR in a 2,450-MHz waveguide system for 10 min, then tested in the abdominal constriction paradigm. Specific absorption rates (SAR) were 23.7 W/kg at 10 mW/cm{sup 2}, 34.6 W/kg at 15 mW/cm{sup 2} and 45.5 W/kg at 20 mW/cm{sup 2}. Confinement in the exposure chamber alone did not appreciably alter body temperature but did appear to induce a stress-associated analgesia that wasmore » insensitive to the opioid receptor blocker naltrexone. Exposure of confined mice to RFR elevated body temperature and further increased analgesia in SAR-dependent manner. The high-SAR RFR-induced analgesia, but not the hyperthermia, was reduced by naltrexone. These findings suggest that (1) RFR produces SAR-dependent hyperthermia and analgesia and (2) RFR-induced analgesia is mediated by opioid mechanisms while confinement-induced analgesia involves non-opioid mechanisms.« less

Protective role of Delphinium denudatum (Jadwar) against morphine induced tolerance and dependence in mice.

PubMed

Zafar, S; Ahmad, M A; Siddiqui, T A

2001-11-01

Chronic treatment with Delphinium denudatum (Dd) (Jadwar) (family: Ranunculaceae, 200-1600 mg/kg) suppressed morphine withdrawal jumps in a dose-dependent manner, a sign of the development of dependence to opiate as assessed by naloxone (2 mg/kg) precipitation withdrawal on day 10 of testing in mice. Repeated administration of Dd (200-1600 mg/kg) for 9 days attenuated the development of tolerance to the analgesic effect of morphine (10 mg/kg), also produces significant change in tail-flick latency from the saline pretreated group in a dose-dependent manner.

Brownian motion in inhomogeneous suspensions.

PubMed

Yang, Mingcheng; Ripoll, Marisol

2013-06-01

The Langevin description of Brownian motion in inhomogeneous suspensions is here revisited. Inhomogeneous suspensions are characterized by a position-dependent friction coefficient, which can significantly influence the dynamics of the suspended particles. Outstanding examples are suspensions in confinement or in the presence of a temperature gradient. The Langevin approach in inhomogeneous systems encounters a fundamental difficulty related to the interpretation of the multiplicative noise induced by the position-dependent friction. We show that the so-called Ito-Stratonovich dilemma is originated by the violation of the macroscopic force balance condition in the traditional procedure of eliminating the fast variables. Repairing this deficit, we rederive the extended overdamped Langevin equation directly from the infradamped Langevin equation. This is without invoking the Fokker-Planck formalism, such that the self-completeness of the Langevin framework is restored. Furthermore, we derive the generalized forms of the drift-force relation and the Smoluchowski equation for inhomogeneous suspensions in a straightforward manner.

The influence of hypoxia on the thermal sensitivity of skin colouration in the bearded dragon, Pogona vitticeps.

PubMed

de Velasco, Jesus Barraza; Tattersall, Glenn J

2008-09-01

One physiological mechanism used by reptiles to remain within thermal optima is their ability to reversibly alter skin colour, imparting changes in overall reflectance, and influencing the rate of heat gain from incident radiation. The ability to lighten or darken their skin is caused by the movement of pigment within the dermal chromatophore cells. Additionally, lizards, as ectotherms, significantly lower their preferred body temperatures when experiencing stressors such as hypoxia. This decrease in preferred temperature has been proposed to be the result of a downward adjustment of the thermal set-point, the temperature around which the body temperature is typically defended. We tested the hypothesis that lightening of the skin in lizards would be modified by hypoxia in a manner consistent with the known reduction in preferred temperatures. Skin colouration values of the dorsal skin of bearded dragons were analysed at three different levels of oxygen (20.8, 9.9 and 4.9 kPa) and at temperatures spanning the preferred temperature range (30, 32, 34, 36, 38 and 40 C). Hypoxic lizards lightened their skin at lower ambient temperatures more than normoxic ones, and in an oxygen-dependent fashion. The orchestrated adjustment of skin reflectance suggests that this physiological trait is being regulated at a new and lower set-point. Evidence from this study demonstrates that skin colouration plays a role in body temperature regulation and that the reduction in temperature set-point so prevalent in hypoxia is also manifested in this physiological trait.

Effects of environmentally relevant concentrations of atrazine on gonadal development of snapping turtles (Chelydra serpentina).

PubMed

de Solla, Shane R; Martin, Pamela A; Fernie, Kimberly J; Park, Brad J; Mayne, Gregory

2006-02-01

The herbicide atrazine has been suspected of affecting sexual development by inducing aromatase, resulting in the increased conversion of androgens to estrogens. We used snapping turtles (Chelydra serpentina), a species in which sex is dependent on the production of estrogen through aromatase activity in a temperature-dependent manner, to investigate if environmentally relevant exposures to atrazine affected gonadal development. Eggs were incubated in soil to which atrazine was applied at a typical field application rate (3.1 L/ha), 10-fold this rate (31 L/ha), and a control rate (no atrazine) for the duration of embryonic development. The incubation temperature (25 degrees C) was selected to produce only males. Although some males with testicular oocytes and females were produced in the atrazine-treated groups (3.3-3.7%) but not in the control group, no statistical differences were found among treatments. Furthermore, snapping turtle eggs collected from natural nests in a corn field were incubated at the pivotal temperature (27.5 degrees C) at which both males and females normally would be produced, and some males had oocytes in the testes (15.4%). The presence of low numbers of males with oocytes may be a natural phenomenon, and we have limited evidence to suggest that the presence of normal males with oocytes may represent a feminizing effect of atrazine. Histological examination of the thyroid gland revealed no effect on thyroid morphology.

Fracture Properties of Polystyrene Aggregate Concrete after Exposure to High Temperatures.

PubMed

Tang, Waiching; Cui, Hongzhi; Tahmasbi, Soheil

2016-07-28

This paper mainly reports an experimental investigation on the residual mechanical and fracture properties of polystyrene aggregate concrete (PAC) after exposure to high temperatures up to 800 degrees Celsius. The fracture properties namely, the critical stress intensity factor ( K I C S ), the critical crack tip opening displacement ( CTOD C ) for the Two-Parameter Model, and the fracture energy ( G F ) for the Fictitious Crack Model were examined using the three-point bending notched beam test, according to the RILEM recommendations. The effects of polystyrene aggregate (PA) content and temperature levels on the fracture and mechanical properties of concrete were investigated. The results showed that the mechanical properties of PAC significantly decreased with increase in temperature level and the extent of which depended on the PA content in the mixture. However, at a very high temperature of 800 °C, all samples showed 80 percent reduction in modulus of elasticity compared to room temperature, regardless of the level of PA content. Fracture properties of control concrete (C) and PAC were influenced by temperature in a similar manner. Increasing temperature from 25 °C to 500 °C caused almost 50% reduction of the fracture energy for all samples while 30% increase in fracture energy was occurred when the temperature increased from 500 °C to 800 °C. It was found that adding more PA content in the mixture lead to a more ductile behaviour of concrete.

Effect of ambient temperature on the proliferation of brown adipocyte progenitors and endothelial cells during postnatal BAT development in Syrian hamsters.

PubMed

Nagaya, Kazuki; Okamatsu-Ogura, Yuko; Nio-Kobayashi, Junko; Nakagiri, Shohei; Tsubota, Ayumi; Kimura, Kazuhiro

2018-04-02

In Syrian hamsters, brown adipose tissue (BAT) develops postnatally through the proliferation and differentiation of brown adipocyte progenitors. In the study reported here, we investigated how ambient temperature influenced BAT formation in neonatal hamsters. In both hamsters raised at 23 or 30 °C, the interscapular fat changed from white to brown coloration in an age-dependent manner and acquired the typical morphological features of BAT by day 16. However, the expression of uncoupling protein 1, a brown adipocyte marker, and of vascular endothelial growth factor α were lower in the group raised at 30 °C than in that raised at 23 °C. Immunofluorescent staining revealed that the proportion of Ki67-expressing progenitors and endothelial cells was lower in the 30 °C group than in the 23 °C group. These results indicate that warm ambient temperature suppresses the proliferation of brown adipocyte progenitors and endothelial cells and negatively affects the postnatal development of BAT in Syrian hamsters.

Measurement of magnetic property of FePt granular media at near Curie temperature

NASA Astrophysics Data System (ADS)

Yang, H. Z.; Chen, Y. J.; Leong, S. H.; An, C. W.; Ye, K. D.; Hu, J. F.

2017-02-01

The characterization of the magnetic switching behavior of heat assisted magnetic recording (HAMR) media at near Curie temperature (Tc) is important for high density recording. In this study, we measured the magnetic property of FePt granular media (with room temperature coercivity 25 kOe) at near Tc with a home built HAMR testing instrument. The local area of HAMR media is heated to near Tc by a flat-top optical heating beam. The magnetic property in the heated area was in-situ measured by a magneto-optic Kerr effect (MOKE) testing beam. The switching field distribution (SFD) and coercive field (Hc) of the FePt granular media and their dependence on the optical heating power at near Tc were studied. We measured the DC demagnetization (DCD) signal with pulsed laser heating at different optical powers. We also measured the Tc distribution of the media by measuring the AC magnetic signal as a function of optical heating power. In a summary, we studied the SFD, Hc of the HAMR media at near Tc in a static manner. The present methodology will facilitate the HAMR media testing.

3D printed sample holder for in-operando EPR spectroscopy on high temperature polymer electrolyte fuel cells

NASA Astrophysics Data System (ADS)

Niemöller, Arvid; Jakes, Peter; Kayser, Steffen; Lin, Yu; Lehnert, Werner; Granwehr, Josef

2016-08-01

Electrochemical cells contain electrically conductive components, which causes various problems if such a cell is analyzed during operation in an EPR resonator. The optimum cell design strongly depends on the application and it is necessary to make certain compromises that need to be individually arranged. Rapid prototyping presents a straightforward option to implement a variable cell design that can be easily adapted to changing requirements. In this communication, it is demonstrated that sample containers produced by 3D printing are suitable for EPR applications, with a particular emphasis on electrochemical applications. The housing of a high temperature polymer electrolyte fuel cell (HT-PEFC) with a phosphoric acid doped polybenzimidazole membrane was prepared from polycarbonate by 3D printing. Using a custom glass Dewar, this fuel cell could be operated at temperatures up to 140 °C in a standard EPR cavity. The carbon-based gas diffusion layer showed an EPR signal with a characteristic Dysonian line shape, whose evolution could be monitored in-operando in a non-invasive manner.

3D printed sample holder for in-operando EPR spectroscopy on high temperature polymer electrolyte fuel cells.

PubMed

Niemöller, Arvid; Jakes, Peter; Kayser, Steffen; Lin, Yu; Lehnert, Werner; Granwehr, Josef

2016-08-01

Electrochemical cells contain electrically conductive components, which causes various problems if such a cell is analyzed during operation in an EPR resonator. The optimum cell design strongly depends on the application and it is necessary to make certain compromises that need to be individually arranged. Rapid prototyping presents a straightforward option to implement a variable cell design that can be easily adapted to changing requirements. In this communication, it is demonstrated that sample containers produced by 3D printing are suitable for EPR applications, with a particular emphasis on electrochemical applications. The housing of a high temperature polymer electrolyte fuel cell (HT-PEFC) with a phosphoric acid doped polybenzimidazole membrane was prepared from polycarbonate by 3D printing. Using a custom glass Dewar, this fuel cell could be operated at temperatures up to 140°C in a standard EPR cavity. The carbon-based gas diffusion layer showed an EPR signal with a characteristic Dysonian line shape, whose evolution could be monitored in-operando in a non-invasive manner. Copyright © 2016. Published by Elsevier Inc.

Single crystal plastic behavior of a single-phase, face-center-cubic-structured, equiatomic FeNiCrCo alloy

DOE PAGES

Wu, Zhenggang; Gao, Y. F.; Bei, Hongbin

2015-07-25

To understand the fundamental deformation mechanisms of compositionally complex alloys, single crystals of a multi-component equiatomic FeNiCoCr alloy with face-centered cubic (FCC) structure were grown for mechanical studies. Similarly to typical FCC pure metals, slip trace analyses indicate that dislocation slips take place on (1 1 1) planes along [11¯0] directions. The critical resolved shear stress (CRSS) obeys the Schmid law at both 77 and 293 K, and tension–compression asymmetry is not observed. Although this material slips in a normal FCC manner both at 293 and 77 K, compared to typical FCC metals the CRSS’s strong temperature dependence is abnormal.

Physiological roles of A1 and A2A adenosine receptors in regulating heart rate, body temperature, and locomotion as revealed using knockout mice and caffeine.

PubMed

Yang, Jiang-Ning; Chen, Jiang-Fan; Fredholm, Bertil B

2009-04-01

Heart rate (HR), body temperature (Temp), locomotor activity (LA), and oxygen consumption (O(2)C) were studied in awake mice lacking one or both of the adenosine A(1) or A(2A) receptors (A(1)R or A(2A)R, respectively) using telemetry and respirometry, before and after caffeine administration. All parameters were lower during day than night and higher in females than males. When compared with wild-type (WT) littermates, HR was higher in male A(1)R knockout (A(1)RKO) mice but lower in A(2A)RKO mice and intermediate in A(1)-A(2A)R double KO mice. A single dose of an unselective beta-blocker (timolol; 1 mg/kg) abolished the HR differences between these genotypes. Deletion of A(1)Rs had little effect on Temp, whereas deletion of A(2A)Rs increased it in females and decreased it in males. A(1)-A(2A)RKO mice had lower Temp than WT mice. LA was unaltered in A(1)RKO mice and lower in A(2A)RKO and A(1)-A(2A)RKO mice than in WT mice. Caffeine injection increased LA but only in mice expressing A(2A)R. Caffeine ingestion also increased LA in an A(2A)R-dependent manner in male mice. Caffeine ingestion significantly increased O(2)C in WT mice, but less in the different KO mice. Injection of 30 mg/kg caffeine decreased Temp, especially in KO mice, and hence in a manner unrelated to A(1)R or A(2A)R blockade. Selective A(2B) antagonism had little or no effect. Thus A(1)R and A(2A)R influence HR, Temp, LA, and O(2)C in mice in a sex-dependent manner, indicating effects of endogenous adenosine. The A(2A)R plays an important role in the modulation of O(2)C and LA by acute and chronic caffeine administration. There is also evidence for effects of higher doses of caffeine being independent of both A(1)R and A(2A)R.

Influence of Light and Temperature on Monoterpene Emission Rates from Slash Pine

PubMed Central

Tingey, David T.; Manning, Marybeth; Grothaus, Louis C.; Burns, Walter F.

1980-01-01

There is a growing awareness of vegetation's role as a source of potentially reactive hydrocarbons that may serve as photochemical oxidant precursors. This study assessed the influence of light and temperature, independently, on monoterpene emissions from slash pine (Pinus elliottii Engelm.). Plants were preconditioned in a growth chamber, then transferred to an environmentally controlled gas exchange chamber. Samples of the chamber atmosphere were collected; the monoterpenes were concentrated cryogenically and measured by gas chromatography. Five monoterpenes (α-pinene, β-pinene, myrcene, limonene, and β-phellandrene) were present in the vapor phase surrounding the plants in sufficient quantity for reliable measurement. Light did not directly influence monoterpene emission rates since the emissions were similar in both the dark and at various light intensities. Monoterpene emission rates increased exponentially with temperature (i. e. emissions depend on temperature in a log-linear manner). The summed emissions of the five monoterpenes ranged from 3 to 21 micrograms C per gram dry weight per hour as temperature was increased from 20 to 46 C. Initially, emission rates from heat-stressed needles were similar to healthy needles, but rates decreased 11% per day. Daily carbon loss through monoterpene emissions accounted for approximately 0.4% of the carbon fixed during photosynthesis. PMID:16661285

Influence of light and temperature on monoterpene emission rates from slash pine.

PubMed

Tingey, D T; Manning, M; Grothaus, L C; Burns, W F

1980-05-01

There is a growing awareness of vegetation's role as a source of potentially reactive hydrocarbons that may serve as photochemical oxidant precursors. This study assessed the influence of light and temperature, independently, on monoterpene emissions from slash pine (Pinus elliottii Engelm.). Plants were preconditioned in a growth chamber, then transferred to an environmentally controlled gas exchange chamber. Samples of the chamber atmosphere were collected; the monoterpenes were concentrated cryogenically and measured by gas chromatography. Five monoterpenes (alpha-pinene, beta-pinene, myrcene, limonene, and beta-phellandrene) were present in the vapor phase surrounding the plants in sufficient quantity for reliable measurement. Light did not directly influence monoterpene emission rates since the emissions were similar in both the dark and at various light intensities. Monoterpene emission rates increased exponentially with temperature (i. e. emissions depend on temperature in a log-linear manner). The summed emissions of the five monoterpenes ranged from 3 to 21 micrograms C per gram dry weight per hour as temperature was increased from 20 to 46 C. Initially, emission rates from heat-stressed needles were similar to healthy needles, but rates decreased 11% per day. Daily carbon loss through monoterpene emissions accounted for approximately 0.4% of the carbon fixed during photosynthesis.

Transition Helmholtz free energy, entropy, and heat capacity of free-standing smectic films in water: A mean-field treatment

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

Śliwa, Izabela, E-mail: izasliwa@ifmpan.poznan.pl; Zakharov, A. V., E-mail: alexandre.zakharov@yahoo.ca

Using the extended McMillan's mean field approach with anisotropic forces a study of both the structural and thermodynamic properties of free-standing smectic film (FSSF) in water on heating to the isotropic temperature is carried out numerically. By solving the self-consistent nonlinear equations for the order parameters, we obtained that the smectic-A-isotropic (AI) transition occurs through the series of layer-thinning transitions causing the films to thin in the stepwise manner as the temperature is increased above the bulk smectic-A-isotropic temperature T{sub AI}(bulk). With enhanced pair interactions in the bounding layers, the smectic-isotropic transition corresponds to smectic melting of the central layers.more » The effects of surface “enhanced” pair interactions in the bounding layers and of film thickness on the orientational and translational order parameters, the Helmholtz free energy and entropy, as well as the temperature dependence of the heat capacity of FSSFs, have also been investigated. Reasonable agreement between the theoretically predicted and the experimentally obtained – by means of optical microscopy and ellipsometry techniques – data of the temperature when the thin decylcyanobiphenyl smectic film immersing in water ruptures has been obtained.« less

The impact of exercise-induced core body temperature elevations on coagulation responses.

PubMed

Veltmeijer, Matthijs T W; Eijsvogels, Thijs M H; Barteling, Wideke; Verbeek-Knobbe, Kitty; van Heerde, Waander L; Hopman, Maria T E

2017-02-01

Exercise induces changes in haemostatic parameters and core body temperature (CBT). We aimed to assess whether exercise-induced elevations in CBT induce pro-thrombotic changes in a dose-dependent manner. Observational study. CBT and haemostatic responses were measured in 62 participants of a 15-km road race at baseline and immediately after finishing. As haemostasis assays are routinely performed at 37°C, we corrected the assay temperature for the individual's actual CBT at baseline and finish in a subgroup of n=25. All subjects (44±11 years, 69% male) completed the race at a speed of 12.1±1.8km/h. CBT increased significantly from 37.6±0.4°C to 39.4±0.8°C (p<0.001). Post-exercise, haemostatic activity was increased, as expressed by accelerated thrombin generation and an attenuated plasmin response. Synchronizing assay temperature to the subjects' actual CBT resulted in additional differences and stronger acceleration of thrombin generation parameters. This study demonstrates that exercise induces a prothrombotic state, which might be partially dependent on the magnitude of the exercise-induced CBT rise. Synchronizing the assay temperature to approximate the subject's CBT is essential to obtain more accurate insight in the haemostatic balance during thermoregulatory challenging situations. Finally, this study shows that short-lasting exposure to a CBT of 41.2°C does not result in clinical symptoms of severe coagulation. We therefore hypothesize that prolonged exposure to a high CBT or an individual-specific CBT threshold needs to be exceeded before derailment of the haemostatic balance occurs. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

The epigenetic memory of temperature during embryogenesis modifies the expression of bud burst-related genes in Norway spruce epitypes.

PubMed

Carneros, Elena; Yakovlev, Igor; Viejo, Marcos; Olsen, Jorunn E; Fossdal, Carl Gunnar

2017-09-01

Epigenetic memory affects the timing of bud burst phenology and the expression of bud burst-related genes in genetically identical Norway spruce epitypes in a manner usually associated with ecotypes. In Norway spruce, a temperature-dependent epigenetic memory established during embryogenesis affects the timing of bud burst and bud set in a reproducible and predictable manner. We hypothesize that the clinal variation in these phenological traits, which is associated with adaptation to growth under frost-free conditions, has an epigenetic component. In Norway spruce, dehydrins (DHNs) have been associated with extreme frost tolerance. DHN transcript levels decrease gradually prior to flushing, a time when trees are highly sensitive to frost. Furthermore, EARLY BUD BREAK 1 genes (EBB1) and the FT-TFL1-LIKE 2-gene (PaFTL2) were previously suggested to be implied in control of bud phenology. Here we report an analysis of transcript levels of 12 DHNs, 3 EBB1 genes and FTL2 in epitypes of the same genotype generated at different epitype-inducing temperatures, before and during spring bud burst. Earlier flushing of epitypes originating from embryos developed at 18 °C as compared to 28 °C, was associated with differential expression of these genes between epitypes and between buds and last year's needles. The majority of these genes showed significantly different expressions between epitypes in at least one time point. The general trend in DHN expression pattern in buds showed the expected reduction in transcript levels when approaching flushing, whereas, surprisingly, transcript levels peaked later in needles, mainly at the moment of bud burst. Collectively, our results demonstrate that the epigenetic memory of temperature during embryogenesis affects bud burst phenology and expression of the bud burst-related DHN, EBB1 and FTL2 genes in genetically identical Norway spruce epitypes.

Season-dependent effects of photoperiod and temperature on circadian rhythm of arylalkylamine N-acetyltransferase2 gene expression in pineal organ of an air-breathing catfish, Clarias gariepinus.

PubMed

Singh, Kshetrimayum Manisana; Saha, Saurav; Gupta, Braj Bansh Prasad

2017-08-01

Arylalkylamine N-acetyltransferase (AANAT) activity, aanat gene expression and melatonin production have been reported to exhibit prominent circadian rhythm in the pineal organ of most species of fish. Three types of aanat genes are expressed in fish, but the fish pineal organ predominantly expresses aanat2 gene. Increase and decrease in daylength is invariably associated with increase and decrease in temperature, respectively. But so far no attempt has been made to delineate the role of photoperiod and temperature in regulation of the circadian rhythm of aanat2 gene expression in the pineal organ of any fish with special reference to seasons. Therefore, we studied effects of various lighting regimes (12L-12D, 16L-8D, 8L-16D, LL and DD) at a constant temperature (25°C) and effects of different temperatures (15°, 25° and 35°C) under a common photoperiod 12L-12D on circadian rhythm of aanat2 gene expression in the pineal organ of Clarias gariepinus during summer and winter seasons. Aanat2 gene expression in fish pineal organ was studied by measuring aanat2 mRNA levels using Real-Time PCR. Our findings indicate that the pineal organ of C. gariepinus exhibits a prominent circadian rhythm of aanat2 gene expression irrespective of photoperiods, temperatures and seasons, and the circadian rhythm of aanat2 gene expression responds differently to different photoperiods and temperatures in a season-dependent manner. Existence of circadian rhythm of aanat2 gene expression in pineal organs maintained in vitro under 12L-12D and DD conditions as well as a free running rhythm of the gene expression in pineal organ of the fish maintained under LL and DD conditions suggest that the fish pineal organ possesses an endogenous circadian oscillator, which is entrained by light-dark cycle. Copyright © 2017 Elsevier B.V. All rights reserved.

Interaction of plant chimeric calcium/calmodulin-dependent protein kinase with a homolog of eukaryotic elongation factor-1alpha

NASA Technical Reports Server (NTRS)

Wang, W.; Poovaiah, B. W.

1999-01-01

A chimeric Ca2+/calmodulin-dependent protein kinase (CCaMK) was previously cloned and characterized in this laboratory. To investigate the biological functions of CCaMK, the yeast two-hybrid system was used to isolate genes encoding proteins that interact with CCaMK. One of the cDNA clones obtained from the screening (LlEF-1alpha1) has high similarity with the eukaryotic elongation factor-1alpha (EF-1alpha). CCaMK phosphorylated LlEF-1alpha1 in a Ca2+/calmodulin-dependent manner. The phosphorylation site for CCaMK (Thr-257) was identified by site-directed mutagenesis. Interestingly, Thr-257 is located in the putative tRNA-binding region of LlEF-1alpha1. An isoform of Ca2+-dependent protein kinase (CDPK) phosphorylated multiple sites of LlEF-1alpha1 in a Ca2+-dependent but calmodulin-independent manner. Unlike CDPK, CCaMK phosphorylated only one site, and this site is different from CDPK phosphorylation sites. This suggests that the phosphorylation of EF-1alpha by these two kinases may have different functional significance. Although the phosphorylation of LlEF-1alpha1 by CCaMK is Ca2+/calmodulin-dependent, in vitro binding assays revealed that CCaMK binds to LlEF-1alpha1 in a Ca2+-independent manner. This was further substantiated by coimmunoprecipitation of CCaMK and EF-1alpha using the protein extract from lily anthers. Dissociation of CCaMK from EF-1alpha by Ca2+ and phosphorylation of EF-1alpha by CCaMK in a Ca2+/calmodulin-dependent manner suggests that these interactions may play a role in regulating the biological functions of EF-1alpha.

Cadmium induces histopathological injuries and ultrastructural changes in the liver of freshwater turtle (Chinemys reevesii).

PubMed

Huo, Junfeng; Dong, Aiguo; Wang, Yonghui; Lee, Shaochin; Ma, Cungen; Wang, Lan

2017-11-01

The study investigated the histopathological and ultrastructural lesions of liver of freshwater turtle Chinemys reevesii exposed to Cadmium (Cd). The animals were exposed to 0 mg kg -1 (0.85% normal saline (NS)), 7.5 mg kg -1 , 15 mg kg -1 , 30 mg kg -1 Cd chloride separately by intraperitoneal injection. Liver samples were collected for examination of lesions under light and electronic microscopes. Results showed that liver tissues from Cd -treated animals presented various degrees of histopathological lesions. Liver cells showed swollen, degeneration and necrosis with dose-dependent manner. Under electronic microscope, nucleus, mitochondria and rough endoplasmic reticulum presented various degrees of lesions with dose-dependent manner. In conclusion, Cd has significant toxicity on liver tissue of the freshwater turtle, which occurs in a dose-dependent manner. Copyright © 2017 Elsevier Ltd. All rights reserved.

Follicle-stimulating hormone (FSH) unmasks specific high affinity FSH-binding sites in cell-free membrane preparations of porcine granulosa cells

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

Ford, K.A.; LaBarbera, A.R.

1988-11-01

The purpose of these studies was to determine whether changes in FSH receptors correlated with FSH-induced attenuation of FSH-responsive adenylyl cyclase in immature porcine granulosa cells. Cells were incubated with FSH (1-1000 ng/ml) for up to 24 h, treated with acidified medium (pH 3.5) to remove FSH bound to cells, and incubated with (125I)iodo-porcine FSH to quantify FSH-binding sites. FSH increased binding of FSH in a time-, temperature-, and FSH concentration-dependent manner. FSH (200 ng/ml) increased binding approximately 4-fold within 16 h. Analysis of equilibrium saturation binding data indicated that the increase in binding sites reflected a 2.3-fold increase inmore » receptor number and a 5.4-fold increase in apparent affinity. The increase in binding did not appear to be due to 1) a decrease in receptor turnover, since the basal rate of turnover appeared to be very slow; 2) an increase in receptor synthesis, since agents that inhibit protein synthesis and glycosylation did not block the increase in binding; or 3) an increase in intracellular receptors, since agents that inhibit cytoskeletal components had no effect. Agents that increase intracellular cAMP did not affect FSH binding. The increase in binding appeared to result from unmasking of cryptic FSH-binding sites, since FSH increased binding in cell-free membrane preparations to the same extent as in cells. Unmasking of cryptic sites was hormone specific, and the sites bound FSH specifically. Unmasking of sites was reversible in a time- and temperature-dependent manner after removal of bound FSH. The similarity between the FSH dose-response relationships for unmasking of FSH-binding sites and attenuation of FSH-responsive cAMP production suggests that the two processes are functionally linked.« less

Impact of screw and edge dislocations on the thermal conductivity of individual nanowires and bulk GaN: a molecular dynamics study.

PubMed

Termentzidis, Konstantinos; Isaiev, Mykola; Salnikova, Anastasiia; Belabbas, Imad; Lacroix, David; Kioseoglou, Joseph

2018-02-14

We report the thermal transport properties of wurtzite GaN in the presence of dislocations using molecular dynamics simulations. A variety of isolated dislocations in a nanowire configuration are analyzed and found to considerably reduce the thermal conductivity while impacting its temperature dependence in a different manner. Isolated screw dislocations reduce the thermal conductivity by a factor of two, while the influence of edge dislocations is less pronounced. The relative reduction of thermal conductivity is correlated with the strain energy of each of the five studied types of dislocations and the nature of the bonds around the dislocation core. The temperature dependence of the thermal conductivity follows a physical law described by a T -1 variation in combination with an exponent factor that depends on the material's nature, type and the structural characteristics of the dislocation core. Furthermore, the impact of the dislocation density on the thermal conductivity of bulk GaN is examined. The variation and absolute values of the total thermal conductivity as a function of the dislocation density are similar for defected systems with both screw and edge dislocations. Nevertheless, we reveal that the thermal conductivity tensors along the parallel and perpendicular directions to the dislocation lines are different. The discrepancy of the anisotropy of the thermal conductivity grows with increasing density of dislocations and it is more pronounced for the systems with edge dislocations. Besides the fundamental insights of the presented results, these could also be used for the identification of the type of dislocations when one experimentally obtains the evolution of thermal conductivity with temperature since each type of dislocation has a different signature, or one could extract the density of dislocations with a simple measurement of thermal anisotropy.

Temperature-Dependent Expression of phzM and Its Regulatory Genes lasI and ptsP in Rhizosphere Isolate Pseudomonas sp. Strain M18▿

PubMed Central

Huang, Jiaofang; Xu, Yuquan; Zhang, Hongyan; Li, Yaqian; Huang, Xianqing; Ren, Bin; Zhang, Xuehong

2009-01-01

Pseudomonas sp. strain M18, an effective biological control agent isolated from the melon rhizosphere, has a genetic background similar to that of the opportunistic human pathogen Pseudomonas aeruginosa PAO1. However, the predominant phenazine produced by strain M18 is phenazine-1-carboxylic acid (PCA) rather than pyocyanin (PYO); the quantitative ratio of PCA to PYO is 105 to 1 at 28°C in strain M18, while the ratio is 1 to 2 at 37°C in strain PAO1. We first provided evidence that the differential production of the two phenazines in strains M18 and PAO1 is related to the temperature-dependent and strain-specific expression patterns of phzM, a gene involved in the conversion of PCA to PYO. Transcriptional levels of phzM were measured by quantitative real-time PCR, and the activities of both transcriptional and translational phzM′-′lacZ fusions were determined in strains M18 and PAO1, respectively. Using lasI::Gm and ptsP::Gm inactivation M18 mutants, we further show that expression of the phzM gene is positively regulated by the quorum-sensing protein LasI and negatively regulated by the phosphoenolpyruvate phosphotransferase protein PtsP. Surprisingly, the lasI and ptsP regulatory genes were also expressed in a temperature-dependent and strain-specific manner. The differential production of the phenazines PCA and PYO by strains M18 and PAO1 may be a consequence of selective pressure imposed on P. aeruginosa PAO1 and its relative M18 in the two different niches over a long evolutionary process. PMID:19717631

Method for reducing nitrogen oxides in combustion effluents

DOEpatents

Zauderer, Bert

2000-01-01

Method for reducing nitrogen oxides (NO.sub.x) in the gas stream from the combustion of fossil fuels is disclosed. In a narrow gas temperature zone, NO.sub.x is converted to nitrogen by reaction with urea or ammonia with negligible remaining ammonia and other reaction pollutants. Specially designed injectors are used to introduce air atomized water droplets containing dissolved urea or ammonia into the gaseous combustion products in a manner that widely disperses the droplets exclusively in the optimum reaction temperature zone. The injector operates in a manner that forms droplet of a size that results in their vaporization exclusively in this optimum NO.sub.x -urea/ammonia reaction temperature zone. Also disclosed is a design of a system to effectively accomplish this injection.

41 CFR 102-74.185 - What heating and cooling policy must Federal agencies follow in Federal facilities?

Code of Federal Regulations, 2010 CFR

2010-07-01

... overall energy efficient and economical manner; (b) Maintain temperatures to maximize customer satisfaction by conforming to local commercial equivalent temperature levels and operating practices; (c) Set...

Infrared Imaging of Nitric Oxide-Mediated Blood Flow in Human Sickle Cell Disease

PubMed Central

Gorbach, Alexander M.; Ackerman, Hans C.; Liu, Wei-Min; Meyer, Joseph M.; Littel, Patricia L.; Seamon, Catherine; Footman, Eleni; Chi, Amy; Zorca, Suzana; Krajewski, Megan L.; Cuttica, Michael J.; Machado, Roberto F.; Cannon, Richard O.; Kato, Gregory J.

2012-01-01

Vascular dysfunction is an important pathophysiologic manifestation of sickle cell disease (SCD), a condition that increases risk of pulmonary hypertension and stroke. We hypothesized that infrared (IR) imaging would detect changes in cutaneous blood flow reflective of vascular function. We performed IR imaging and conventional strain gauge plethysmography in twenty-five adults with SCD at baseline and during intra-arterial infusions of an endothelium-dependent vasodilator acetylcholine (ACh), an endothelium-independent vasodilator sodium nitroprusside (SNP), and a NOS inhibitor L-NMMA. Skin temperature measured by IR imaging increased in a dose-dependent manner to graded infusions of ACh (+1.1° C, p < 0.0001) and SNP (+0.9° C, p < 0.0001), and correlated with dose-dependent increases in forearm blood flow (ACh: +19.9 mL/min/100mL, p < 0.0001; rs = 0.57, p = 0.003; SNP: +8.6 mL/min/100mL, p < 0.0001; r = 0.70, p = 0.0002). Although IR measurement of skin temperature accurately reflected agonist-induced increases in blood flow, it was less sensitive to decreases in blood flow caused by NOS inhibition. Baseline forearm skin temperature measured by IR imaging correlated significantly with baseline forearm blood flow (31.8±0.2° C, 6.0±0.4 mL/min/100mL; r = 0.58, p = 0.003), and appeared to represent a novel biomarker of vascular function. It predicted a blunted blood flow response to SNP (r = −0.61, p = 0.002), and was independently associated with a marker of pulmonary artery pressure, as well as hemoglobin level, diastolic blood pressure, homocysteine, and cholesterol (R2 = 0.84, p < 0.0001 for the model). IR imaging of agonist-stimulated cutaneous blood flow represents a less cumbersome alternative to plethysmography methodology. Measurement of baseline skin temperature by IR imaging may be a useful new marker of vascular risk in adults with SCD. PMID:22784510

Simulation of Field Dependence of Critical Current Densities of Bulk High Tc Superconducting Materials regarding Thermally Activated Flux Motion

NASA Astrophysics Data System (ADS)

Santosh, M.; Naik, S. Pavan Kumar; Koblischka, M. R.

2017-07-01

In the upcoming generation, bulk high temperature superconductors (HTS) will play a crucial and a promising role in numerous industrial applications ranging from Maglev trains to magnetic resonance imaging, etc. Especially, the bulk HTS as permanent magnets are suitable due to the fact that they can trap magnetic fields being several orders of magnitude higher than those of the best hard ferromagnets. The bulk HTS LREBa2Cu3O7-δ (LREBCO or LRE-123, LRE: Y, Gd, etc.,) materials could obtain very powerful compact superconducting super-magnets, which can be operated at the cheaper liquid nitrogen temperature or below due to higher critical temperatures (i.e., ∼90 K). As a result, the new advanced technology can be utilized in a more attractive manner for a variety of technological and medical applications which have the capacity to revolutionize the field. An understanding of the magnetic field dependence of the critical current density (J c(H)) is important to develop better adapted materials. To achieve this goal, a variety of Jc (H) behaviours of bulk LREBCO samples were modelled regarding thermally activated flux motion. In essence, the Jc (H) curves follows a certain criterion where an exponential model is applied. However, to fit the complete Jc (H) curve of the LRE-123 samples an unique model is necessary to explain the behavior at low and high fields. The modelling of the various superconducting materials could be understood in terms of the pinning mechanisms.

Investigation into Formation of Lipid Hydroperoxides from Membrane Lipids in Escherichia coli O157:H7 following Exposure to Hot Water.

PubMed

Cálix-Lara, Thelma F; Kirsch, Katie R; Hardin, Margaret D; Castillo, Alejandro; Smith, Stephen B; Taylor, Thomas M

2015-06-01

Although studies have shown antimicrobial treatments consisting of hot water sprays alone or paired with lactic acid rinses are effective for reducing Escherichia coli O157:H7 loads on beef carcass surfaces, the mechanisms by which these interventions inactivate bacterial pathogens are still poorly understood. It was hypothesized that E. coli O157:H7 exposure to hot water in vitro at rising temperatures for longer time periods would result in increasing deterioration of bacterial outer membrane lipids, sensitizing the pathogen to subsequent lactic acid application. Cocktails of E. coli O157:H7 strains were subjected to hot water at 25 (control) 65, 75, or 85 °C incrementally up to 60 s, after which surviving cells were enumerated by plating. Formation of lipid hydroperoxides from bacterial membranes and cytoplasmic accumulation of L-lactic acid was quantified spectrophotometrically. Inactivation of E. coli O157:H7 proceeded in a hot water exposure duration- and temperature-dependent manner, with populations being reduced to nondetectable numbers following heating of cells in 85 °C water for 30 and 60 s (P < 0.05). Lipid hydroperoxide formation was not observed to be dependent upon increasing water temperature or exposure period. The data suggest that hot water application prior to organic acid application may function to increase the sensitivity of E. coli O157:H7 cells by degrading membrane lipids.

Anti-inflammatory activity of 6-hydroxy-2,7-dimethoxy-1,4-henanthraquinone from tuberous roots of yam (Dioscorea batatas) through inhibition of prostaglandin D₂ and leukotriene C₄ production in mouse bone marrow-derived mast cells.

PubMed

Jin, Meihua; Lu, Yue; Yang, Ju Hye; Jo, Tae Hyung; Park, Young In; Lee, Chong-Kil; Park, Sang-Jo; Son, Kun Ho; Chang, Hyeun Wook

2011-09-01

6-Hydroxy-2,7-dimethoxy-1,4-phenanthraquinone (PAQ) isolated from the tuberous roots of Yam (Dioscorea batatas) inhibited cyclooxygenase-2 (COX-2) and cyclooxygenase-1 (COX-1) dependent prostaglandin D(2) (PGD(2)) generation in mouse bone marrow-derived mast cells in a concentration-dependent manner with IC(50) values of 0.08 μM and 0.27 μM, respectively. In the Western blotting with specific anti-COX-2 antibodies, the decrease of the quantity of PGD(2) was accompanied by a decrease in the COX-2 protein level. But PAQ did not affect COX-1 protein level. In addition, this compound inhibited 5-lipoxygenase (5-LOX) dependent production of leukotriene C(4) in a dose-dependent manner, with an IC(50) of 0.032 μM. These results demonstrate that PAQ has a dual COX-2/5-LOX inhibitory activity. This compound also inhibited the degranulation reaction in a dose-dependent manner with an IC(50) of 2.7 μM. Thus, these results suggest that PAQ may be useful in regulating mast cell-mediated inflammatory diseases.

Double-stranded RNA interferes in a sequence-specific manner with the infection of representative members of the two viroid families

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

Carbonell, Alberto; Martinez de Alba, Angel-Emilio; Flores, Ricardo

2008-02-05

Infection by viroids, non-protein-coding circular RNAs, occurs with the accumulation of 21-24 nt viroid-derived small RNAs (vd-sRNAs) with characteristic properties of small interfering RNAs (siRNAs) associated to RNA silencing. The vd-sRNAs most likely derive from dicer-like (DCL) enzymes acting on viroid-specific dsRNA, the key elicitor of RNA silencing, or on the highly structured genomic RNA. Previously, viral dsRNAs delivered mechanically or agroinoculated have been shown to interfere with virus infection in a sequence-specific manner. Here, we report similar results with members of the two families of nuclear- and chloroplast-replicating viroids. Moreover, homologous vd-sRNAs co-delivered mechanically also interfered with one ofmore » the viroids examined. The interference was sequence-specific, temperature-dependent and, in some cases, also dependent on the dose of the co-inoculated dsRNA or vd-sRNAs. The sequence-specific nature of these effects suggests the involvement of the RNA induced silencing complex (RISC), which provides sequence specificity to RNA silencing machinery. Therefore, viroid titer in natural infections might be regulated by the concerted action of DCL and RISC. Viroids could have evolved their secondary structure as a compromise between resistance to DCL and RISC, which act preferentially against RNAs with compact and relaxed secondary structures, respectively. In addition, compartmentation, association with proteins or active replication might also help viroids to elude their host RNA silencing machinery.« less

The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus.

PubMed

Kawai, Nobuhiro; Sakai, Noriaki; Okuro, Masashi; Karakawa, Sachie; Tsuneyoshi, Yosuke; Kawasaki, Noriko; Takeda, Tomoko; Bannai, Makoto; Nishino, Seiji

2015-05-01

The use of glycine as a therapeutic option for improving sleep quality is a novel and safe approach. However, despite clinical evidence of its efficacy, the details of its mechanism remain poorly understood. In this study, we investigated the site of action and sleep-promoting mechanisms of glycine in rats. In acute sleep disturbance, oral administration of glycine-induced non-rapid eye movement (REM) sleep and shortened NREM sleep latency with a simultaneous decrease in core temperature. Oral and intracerebroventricular injection of glycine elevated cutaneous blood flow (CBF) at the plantar surface in a dose-dependent manner, resulting in heat loss. Pretreatment with N-methyl-D-aspartate (NMDA) receptor antagonists AP5 and CGP78608 but not the glycine receptor antagonist strychnine inhibited the CBF increase caused by glycine injection into the brain. Induction of c-Fos expression was observed in the hypothalamic nuclei, including the medial preoptic area (MPO) and the suprachiasmatic nucleus (SCN) shell after glycine administration. Bilateral microinjection of glycine into the SCN elevated CBF in a dose-dependent manner, whereas no effect was observed when glycine was injected into the MPO and dorsal subparaventricular zone. In addition, microinjection of D-serine into the SCN also increased CBF, whereas these effects were blocked in the presence of L-701324. SCN ablation completely abolished the sleep-promoting and hypothermic effects of glycine. These data suggest that exogenous glycine promotes sleep via peripheral vasodilatation through the activation of NMDA receptors in the SCN shell.

Seasonal shifts in sex ratios are mediated by maternal effects and fluctuating incubation temperatures.

PubMed

Carter, Amanda W; Bowden, Rachel M; Paitz, Ryan T

2017-04-01

Sex-specific maternal effects can be adaptive sources of phenotypic plasticity. Reptiles with temperature-dependent sex determination (TSD) are a powerful system to investigate such maternal effects because offspring phenotype, including sex, can be sensitive to maternal influences such as oestrogens and incubation temperatures.In red-eared slider turtles ( Trachemys scripta ), concentrations of maternally derived oestrogens and incubation temperatures increase across the nesting season; we wanted to determine if sex ratios shift in a seasonally concordant manner, creating the potential for sex-specific maternal effects, and to define the sex ratio reaction norms under fluctuating temperatures across the nesting season.Eggs from early and late season clutches were incubated under a range of thermally fluctuating temperatures, maternally derived oestradiol concentrations were quantified via radioimmunoassay, and hatchling sex was identified. We found that late season eggs had higher maternal oestrogen concentrations and were more likely to produce female hatchlings. The sex ratio reaction norm curves systematically varied with season, such that with even a slight increase in temperature (0.5°C), late season eggs produced up to 49% more females than early season eggs.We found a seasonal shift in sex ratios which creates the potential for sex-specific phenotypic matches across the nesting season driven by maternal effects. We also describe, for the first time, systematic variation in the sex ratio reaction norm curve within a single population in a species with TSD.

Local-structure change rendered by electronic localization-delocalization transition in cerium-based metallic glasses

NASA Astrophysics Data System (ADS)

Luo, Qiang; Schwarz, Björn; Swarbrick, Janine C.; Bednarčik, Jozef; Zhu, Yingcai; Tang, Meibo; Zheng, Lirong; Li, Ran; Shen, Jun; Eckert, Jürgen

2018-02-01

With increasing temperature, metallic glasses (MGs) undergo first glass transition without pronounced structural change and then crystallization with distinct variation in structure and properties. The present study shows a structural change of short-range order induced by an electron-delocalization transition, along with an unusual large-volume shrinkage in Ce-based MGs. An f -electron localization-delocalization transition with thermal hysteresis is observed from the temperature dependence of x-ray absorption spectroscopy and resonant inelastic x-ray scattering spectra, indicating an inheritance of the 4 f configuration of pure Ce. However, the delocalization transition becomes broadened due to the local structural heterogeneity and related fluctuation of 4 f levels in the Ce-based MGs. The amorphous structure regulated 4 f delocalization of Ce leads to bond shortening and abnormal structure change of the topological and chemical short-range orders. Due to the hierarchical bonding nature, the structure should change in a similar manner on different length scales (but not isostructurally like the Ce metal) in Ce-based MGs.

Freezing and melting water in lamellar structures.

PubMed Central

Gleeson, J T; Erramilli, S; Gruner, S M

1994-01-01

The manner in which ice forms in lamellar suspensions of dielaidoylphosphatidylethanolamine, dielaidoylphosphatidylcholine, and dioleoylphosphatidylcholine in water depends strongly on the water fraction. For weight fractions between 15 and 9%, the freezing and melting temperatures are significantly depressed below 0 degree C. The ice exhibits a continuous melting transition spanning as much as 20 degrees C. When the water weight fraction is below 9%, ice never forms at temperatures as low as -40 degrees C. We show that when water contained in a lamellar lipid suspension freezes, the ice is not found between the bilayers; it exists as pools of crystalline ice in equilibrium with the bound water associated with the polar lipid headgroups. We have used this effect, together with the known chemical potential of ice, to measure hydration forces between lipid bilayers. We find exponentially decaying hydration repulsion when the bilayers are less than about 7 A apart. For larger separations, we find significant deviations from single exponential decay. PMID:7948683

Thermal control of low-pressure fractionation processes. [in basaltic magma solidification

NASA Technical Reports Server (NTRS)

Usselman, T. M.; Hodge, D. S.

1978-01-01

Thermal models detailing the solidification paths for shallow basaltic magma chambers (both open and closed systems) were calculated using finite-difference techniques. The total solidification time for closed chambers are comparable to previously published calculations; however, the temperature-time paths are not. These paths are dependent on the phase relations and the crystallinity of the system, because both affect the manner in which the latent heat of crystallization is distributed. In open systems, where a chamber would be periodically replenished with additional parental liquid, calculations indicate that the possibility is strong that a steady-state temperature interval is achieved near a major phase boundary. In these cases it is straightforward to analyze fractionation models of the basaltic liquid evolution and their corresponding cumulate sequences. This steady thermal fractionating state can be invoked to explain large amounts of erupted basalts of similar composition over long time periods from the same volcanic center and some rhythmically layered basic cumulate sequences.

Optical and Chemical Characterization of Aerosols Produced from Cooked Meats

NASA Astrophysics Data System (ADS)

Niedziela, R. F.; Foreman, E.; Blanc, L. E.

2011-12-01

Cooking processes can release a variety compounds into the air immediately above a cooking surface. The distribution of compounds will largely depend on the type of food that is being processed and the temperatures at which the food is prepared. High temperatures release compounds from foods like meats and carry them away from the preparation surface into cooler regions where condensation into particles can occur. Aerosols formed in this manner can impact air quality, particularly in urban areas where the amount of food preparation is high. Reported here are the results of laboratory experiments designed to optically and chemically characterize aerosols derived from cooking several types of meats including ground beef, salmon, chicken, and pork both in an inert atmosphere and in synthetic air. The laboratory-generated aerosols are studied using a laminar flow cell that is configured to accommodate simultaneous optical characterization in the mid-infrared and collection of particles for subsequent chemical analysis by gas chromatography. Preliminary optical results in the visible and ultra-violet will also be presented.

The effect of feed moisture and temperature on tannin content, antioxidant and antimicrobial activities of extruded chestnuts.

PubMed

Obiang-Obounou, Brice Wilfried; Ryu, Gi Hyung

2013-12-15

This study focuses on the effect of extrusion processing on tannin reduction, phenolic content, flavonoid content, antioxidant and anitimicrobial activity. Extrusion temperature (120 and 140 °C) and feed moisture (25% and 28%) were used on the tannin content, antioxidant and antimicrobial activities. Extrusion cooking reduced tannin content up to 78%, and improved antioxidant activity from 12.89% to 21.17% in a concentration dependant manner without affecting its antimicrobial activity that varied from 250 to 500 mg. The time-kill assay confirmed the ability of extruded chestnut to reduce Pseudomonas aeruginosa count below detectable limit that reduced the original inoculum by 3log10 CFU/mL. Overall, the results showed that extrusion cooking might serve as a tool for tannin reduction and could improve the antioxidant and antimicrobial properties of chestnut, which might be helpful for chestnut related products in the food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Catastrophic desert formation in Daisyworld.

PubMed

Ackland, Graeme J; Clark, Michael A; Lenton, Timothy M

2003-07-07

Feedback between life and its environment is ubiquitous but the strength of coupling and its global implications remain hotly debated. Abrupt changes in the abundance of life for small changes in forcing provide one indicator of regulation, for example, when vegetation-climate feedback collapses in the formation of a desert. Here we use a two-dimensional "Daisyworld" model with curvature to show that catastrophic collapse of life under gradual forcing provides a testable indicator of environmental feedback. When solar luminosity increases to a critical value, a desert forms across a wide band of the planet. The scale of collapse depends on the strength of feedback. The efficiency of temperature regulation is limited by mutation rate in an analogous manner to the limitation of adaptive fitness in evolutionary theories. The final state of the system emerging from single-site rules can be described by two global quantities: optimization of temperature regulation and maximization of diversity, which are mathematically analogous to energy and entropy in thermodynamics.

Magnetic BiMn-α phase synthesis prediction: First-principles calculation, thermodynamic modeling and nonequilibrium chemical partitioning

DOE PAGES

Zhou, S. H.; Liu, C.; Yao, Y. X.; ...

2016-04-29

BiMn-α is promising permanent magnet. Due to its peritectic formation feature, there is a synthetic challenge to produce single BiMn-α phase. The objective of this study is to assess driving force for crystalline phase pathways under far-from-equilibrium conditions. First-principles calculations with Hubbard U correction are performed to provide a robust description of the thermodynamic behavior. The energetics associated with various degrees of the chemical partitioning are quantified to predict temperature, magnetic field, and time dependence of the phase selection. By assessing the phase transformation under the influence of the chemical partitioning, temperatures, and cooling rate from our calculations, we suggestmore » that it is possible to synthesize the magnetic BiMn-α compound in a congruent manner by rapid solidification. The external magnetic field enhances the stability of the BiMn-α phase. In conclusion, the compositions of the initial compounds from these highly driven liquids can be far from equilibrium.« less

Effects of ionomer morphology on oxygen reduction on Pt

DOE PAGES

Chlistunoff, Jerzy; Pivovar, Bryan

2015-05-21

In this paper, the oxygen reduction reaction (ORR) at the interface between platinum and Nafion 1100 equivalent weight was studied as a function of temperature (20–80 °C), humidity (10–100%), scan rate, the manner in which Nafion film was deposited, and the state of the Pt surface using ultramicroelectrodes employing cyclic voltammetry and chronoamperometry. ORR on smooth electrodes was strongly inhibited under specific conditions dependent on temperature, humidity, and scan rate. From the data presented, we postulate that dynamic changes in the molecular structure of the ionomer at the platinum interface result in differences in ORR voltammetry for films prepared andmore » equilibrated under different conditions. The lack of similar changes for rough, platinized electrodes has been attributed to differences in initial ionomer structure and a higher energy barrier for ionomer restructuring. Finally, these model system studies yield insight into the ionomer-catalyst interface of particular interest for polymer electrolyte fuel cells.« less

Melatonin in concentrated ethanol and ethanol alone attenuate methamphetamine-induced dopamine depletions in C57BL/6J mice.

PubMed

Yu, L; Cherng, C-F G; Chen, C

2002-12-01

The present study aimed to investigate the protective effects of melatonin, ethanol and temperature changes on methamphetamine-induced neurotoxicity in both sexes of mice. Mice exhibited a similar degree of striatal dopamine depletion when methamphetamine was administered during the light and dark cycles. Moreover, 10 mg/kg, but not 5 mg/kg, of methamphetamine, significantly increased body temperature even though dopamine depletions were observed following both doses. Melatonin (80 mg/kg) dissolved in 30% (v/v) ethanol and 30% ethanol alone exerted a moderate to full protection against methamphetamine-induced dopamine depletions in both sexes of mice, whereas the same dose of melatonin in 3% ethanol exerted no protective effect. Furthermore, ethanol attenuated methamphetamine-induced dopamine depletions in a dose-dependent manner with the exception of high efficacy of ethanol at low doses. Finally, the protective effects of ethanol were not blocked by bicuculline. Together, we conclude that ethanol may protect mice against methamphetamine-induced dopamine depletion probably via non-GABAA receptor activation.

Chemical partitioning for the Co--Pr system: First-principles, experiments and energetic calculations to investigate the hard magnetic phase

DOE PAGES

Zhou, S. H.; Kramer, M. J.; Meng, F. Q.; ...

2015-11-14

Co 5Pr-D2 d is promising permanent magnet. Due to its peritectic formation feature, there is a synthetic challenge to produce single Co 5Pr-D2 d phase. The object of our study is to assess thermodynamic pathways for crystalline phases under far-from-equilibrium conditions by combining first-principles calculations and experimental measurements into a robust description of the thermodynamic behavior. The energetic calculations, temperature and time dependent phase selections are predicted under varying degrees of chemical partitioning. Our calculation to assess the chemical partitioning-temperatures indicates that the major magnetic compounds: Co 17Pr 2-α, Co 5Pr-D2 d, Co 19Pr 5-β, and Co 7Pr 2-χ formmore » from a congruent manner to eutectic reactions with decreasing cooling rate. The compositions of the compounds from these highly driven liquids can be far from equilibrium.« less

Suppression of the sonic heat transfer limit in high-temperature heat pipes

NASA Astrophysics Data System (ADS)

Dobran, Flavio

1989-08-01

The design of high-performance heat pipes requires optimization of heat transfer surfaces and liquid and vapor flow channels to suppress the heat transfer operating limits. In the paper an analytical model of the vapor flow in high-temperature heat pipes is presented, showing that the axial heat transport capacity limited by the sonic heat transfer limit depends on the working fluid, vapor flow area, manner of liquid evaporation into the vapor core of the evaporator, and lengths of the evaporator and adiabatic regions. Limited comparisons of the model predictions with data of the sonic heat transfer limits are shown to be very reasonable, giving credibility to the proposed analytical approach to determine the effect of various parameters on the axial heat transport capacity. Large axial heat transfer rates can be achieved with large vapor flow cross-sectional areas, small lengths of evaporator and adiabatic regions or a vapor flow area increase in these regions, and liquid evaporation in the evaporator normal to the main flow.

Correlation of shear and dielectric ion viscosity of dental resins - Influence of composition, temperature and filler content.

PubMed

Steinhaus, Johannes; Hausnerova, Berenika; Haenel, Thomas; Selig, Daniela; Duvenbeck, Fabian; Moeginger, Bernhard

2016-07-01

Shear viscosity and ion viscosity of uncured visible light-curing (VLC) resins and resin based composites (RBC) are correlated with respect to the resin composition, temperature and filler content to check where Dielectric Analysis (DEA) investigations of VLC RBC generate similar results as viscosity measurements. Mixtures of bisphenol A glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) as well as the pure resins were investigated and compared with two commercial VLC dental resins and RBCs (VOCO, Arabesk Top and Grandio). Shear viscosity data was obtained using a Haake Mars III, Thermo Scientific. Ion viscosity measurements performed by a dielectric cure analyzer (DEA 231/1 Epsilon with Mini IDEX-Sensor, Netzsch-Gerätebau). Shear viscosity depends reciprocally on the mobility of molecules, whereas the ion viscosity also depends on the ion concentration as it is affected by both ion concentration and mixture viscosity. Except of pure TEGDMA, shear and ion viscosities depend on the resin composition qualitatively in a similar manner. Furthermore, shear and ion viscosities of the commercial VLC dental resins and composites exhibited the same temperature dependency regardless of filler content. Application of typical rheological models (Kitano and Quemada) revealed that ion viscosity measurements can be described with respect to filler contents of up to 30vol.%. Rheological behavior of a VLC RBC can be characterized by DEA under the condition that the ion concentration is kept constant. Both methods address the same physical phenomenon - motion of molecules. The proposed relations allows for calculating the viscosity of any Bis-GMA-TEGDMA mixture on the base of the viscosities of the pure components. This study demonstrated the applicability of DEA investigations of VLC RBCs with respect to quality assurance purposes. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Yeast multistress resistance and lag-phase characterisation during wine fermentation.

PubMed

Ferreira, David; Galeote, Virginie; Sanchez, Isabelle; Legras, Jean-Luc; Ortiz-Julien, Anne; Dequin, Sylvie

2017-09-01

Saccharomyces cerevisiae has been used to perform wine fermentation for several millennia due to its endurance and unmatched qualities. Nevertheless, at the moment of inoculation, wine yeasts must cope with specific stress factors that still challenge wine makers by slowing down or compromising the fermentation process. To better assess the role of genetic and environmental factors that govern multistress resistance during the wine fermentation lag phase, we used a factorial plan to characterise the individual and combined impact of relevant stress factors on eight S. cerevisiae and two non-S. cerevisiae wine yeast strains that are currently commercialised. The S. cerevisiae strains are very genetically diverse, belonging to the wine and flor groups, and frequently contain a previously described XVIVIII translocation that confers increased resistance to sulphites. We found that low temperature and osmotic stress substantially affected all strains, promoting considerably extended lag phases. SO2 addition had a partially temperature-dependent effect, whereas low phytosterol and thiamine concentrations impacted the lag phase in a strain-dependent manner. No major synergic effects of multistress were detected. The diversity of lag-phase durations and stress responses observed among wine strains offer new insights to better control this critical step of fermentation. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Npvf: Hypothalamic Biomarker of Ambient Temperature Independent of Nutritional Status

PubMed Central

Jaroslawska, Julia; Chabowska-Kita, Agnieszka; Kaczmarek, Monika M.; Kozak, Leslie P.

2015-01-01

The mechanism by which mice, exposed to the cold, mobilize endogenous or exogenous fuel sources for heat production is unknown. To address this issue we carried out experiments using 3 models of obesity in mice: C57BL/6J+/+ (wild-type B6) mice with variable susceptibility to obesity in response to being fed a high-fat diet (HFD), B6. Ucp1-/- mice with variable diet-induced obesity (DIO) and a deficiency in brown fat thermogenesis and B6. Lep-/- with defects in thermogenesis, fat mobilization and hyperphagia. Mice were exposed to the cold and monitored for changes in food intake and body composition to determine their energy balance phenotype. Upon cold exposure wild-type B6 and Ucp1-/- mice with diet-induced obesity burned endogenous fat in direct proportion to their fat reserves and changes in food intake were inversely related to fat mass, whereas leptin-deficient and lean wild-type B6 mice fed a chow diet depended on increased food intake to fuel thermogenesis. Analysis of gene expression in the hypothalamus to uncover a central regulatory mechanism revealed suppression of the Npvf gene in a manner that depends on the reduced ambient temperature and degree of exposure to the cold, but not on adiposity, leptin levels, food intake or functional brown fat. PMID:26070086

High Ambient Temperature Represses Anthocyanin Biosynthesis through Degradation of HY5

PubMed Central

Kim, Sara; Hwang, Geonhee; Lee, Seulgi; Zhu, Jia-Ying; Paik, Inyup; Nguyen, Thom Thi; Kim, Jungmook; Oh, Eunkyoo

2017-01-01

Anthocyanins are flavonoid compounds that protect plant tissues from many environmental stresses including high light irradiance, freezing temperatures, and pathogen infection. Regulation of anthocyanin biosynthesis is intimately associated with environmental changes to enhance plant survival under stressful environmental conditions. Various factors, such as UV, visible light, cold, osmotic stress, and pathogen infection, can induce anthocyanin biosynthesis. In contrast, high temperatures are known to reduce anthocyanin accumulation in many plant species, even drastically in the skin of fruits such as grape berries and apples. However, the mechanisms by which high temperatures regulate anthocyanin biosynthesis in Arabidopsis thaliana remain largely unknown. Here, we show that high ambient temperatures repress anthocyanin biosynthesis through the E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) and the positive regulator of anthocyanin biosynthesis ELONGATED HYPOCOTYL5 (HY5). We show that an increase in ambient temperature decreases expression of genes required in both the early and late steps of the anthocyanin biosynthesis pathway in Arabidopsis seedlings. As a result, seedlings grown at a high temperature (28°C) accumulate less anthocyanin pigment than those grown at a low temperature (17°C). We further show that high temperature induces the degradation of the HY5 protein in a COP1 activity-dependent manner. In agreement with this finding, anthocyanin biosynthesis and accumulation do not respond to ambient temperature changes in cop1 and hy5 mutant plants. The degradation of HY5 derepresses the expression of MYBL2, which partially mediates the high temperature repression of anthocyanin biosynthesis. Overall, our study demonstrates that high ambient temperatures repress anthocyanin biosynthesis through a COP1-HY5 signaling module. PMID:29104579

Tobacco components stimulate Akt-dependent proliferation and NFkappaB-dependent survival in lung cancer cells.

PubMed

Tsurutani, Junji; Castillo, S Sianna; Brognard, John; Granville, Courtney A; Zhang, Chunyu; Gills, Joell J; Sayyah, Jacqueline; Dennis, Phillip A

2005-07-01

Retrospective studies have shown that patients with tobacco-related cancers who continue to smoke after their diagnoses have lower response rates and shorter median survival compared with patients who stop smoking. To provide insight into the biologic basis for these clinical observations, we tested whether two tobacco components, nicotine or the tobacco-specific carcinogen, 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), could activate the Akt pathway and increase lung cancer cell proliferation and survival. Nicotine or NNK, rapidly and potently, activated Akt in non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC) cells. Nicotinic activation of Akt increased phosphorylation of multiple downstream substrates of Akt in a time-dependent manner, including GSK-3, FKHR, tuberin, mTOR and S6K1. Since nicotine or NNK bind to cell surface nicotinic acetylcholine receptors (nAchR), we used RT-PCR to assess expression of nine alpha and three beta nAchR subunits in five NSCLC cell lines and two types of primary lung epithelial cells. NSCLC cells express multiple nAchR subunits in a cell line-specific manner. Agonists of alpha3/alpha4 or alpha7 subunits activated Akt in a time-dependent manner, suggesting that tobacco components utilize these subunits to activate Akt. Cellular outcomes after nicotine or NNK administration were also assessed. Nicotine or NNK increased proliferation of NSCLC cells in an Akt-dependent manner that was closely linked with changes in cyclin D1 expression. Despite similar induction of proliferation, only nicotine decreased apoptosis caused by serum deprivation and/or chemotherapy. Protection conferred by nicotine was NFkappaB-dependent. Collectively, these results identify tobacco component-induced, Akt-dependent proliferation and NFkappaB-dependent survival as cellular processes that could underlie the detrimental effects of smoking in cancer patients.

Ultrathin Injectable Sensors of Temperature, Thermal Conductivity, and Heat Capacity for Cardiac Ablation Monitoring

PubMed Central

Koh, Ahyeon; Gutbrod, Sarah R.; Meyers, Jason D.; Lu, Chaofeng; Webb, Richard Chad; Shin, Gunchul; Li, Yuhang; Kang, Seung-Kyun; Huang, Yonggang

2016-01-01

Knowledge of the distributions of temperature in cardiac tissue during and after ablation is important in advancing a basic understanding of this process, and for improving its efficacy in treating arrhythmias. Technologies that enable real-time temperature detection and thermal characterization in the transmural direction can help to predict the depths and sizes of lesion that form. Herein, materials and designs for an injectable device platform that supports precision sensors of temperature and thermal transport properties distributed along the length of an ultrathin and flexible needle-type polymer substrate are introduced. The resulting system can insert into the myocardial tissue, in a minimally invasive manner, to monitor both radiofrequency ablation and cryoablation, in a manner that has no measurable effects on the natural mechanical motions of the heart. The measurement results exhibit excellent agreement with thermal simulations, thereby providing improved insights into lesion transmurality. PMID:26648177

The development of performance, interference, sharing and coordination criteria

NASA Technical Reports Server (NTRS)

Tillotson, Tom

1986-01-01

The criteria for sharing and coordination between the Earth Exploration Satellite service and other radio services is not fully developed at this time. The purpose is to develop a plan showing how the necessary criteria might be developed. Some criteria does exist in the form of general restrictions, protection criteria, and coordination procedures for space and terrestrial services sharing the same bands. Determining suitable criteria for EES bands depends on the use of the band and the shared services. For example the criteria developed for EES passive sensing band will be developed in a manner different than for a telemetry band. In either case the resultant criteria will be related to, and can be referenced from the system noise power or equivalent noise temperature.

GFP tagging sheds light on protein translocation: implications for key methods in cell biology.

PubMed

Deponte, Marcel

2012-04-01

Green fluorescent protein (GFP) is a powerful tool for studying gene expression, protein localization, protein-protein interactions, calcium concentrations, and redox potentials owing to its intrinsic fluorescence. However, GFP not only contains a chromophore but is also tightly folded in a temperature-dependent manner. The latter property of GFP has recently been exploited (1) to characterize the translocase of the outer mitochondrial membrane and (2) to discriminate between protein transport across and into biomembranes in vivo. I therefore suggest that GFP could be a valuable tool for the general analysis of protein transport machineries and pathways in a variety of organisms. Moreover, results from such studies could be important for the interpretation and optimization of classical experiments using GFP tagging.

CARRIER-LATTICE RELAXATION FOR BROADENING EPR LINEWIDTH IN Nd0.55Sr0.45MnO3

NASA Astrophysics Data System (ADS)

Fan, Jiyu; Zhang, Xiyuan; Tong, Wei; Zhang, Lei; Zhang, Weichun; Zhu, Yan; Shi, Yangguang; Hu, Dazhi; Hong, Bo; Ying, Yao; Ling, Langsheng; Pi, Li; Zhang, Yuheng

2013-12-01

In this paper, we report the electron paramagnetic resonance (EPR) study of perovskite manganite Nd0.55Sr0.45MnO3. Experimental data reveal that the EPR linewidth broadens with a quasilinear manner up to 480 K. The broadening of the EPR linewidth can be understood in terms of the shortening of carrier-lattice relaxation time due to the occurrence of strong carrier-phonon interactions. Two same activation energies obtained respectively from the temperature dependence of EPR intensity and resistivity indicate that the linewidth variation is correlated to the small polaron hopping. Therefore, the carrier-lattice coupling play a major role for deciding its magnetism in the present system.

Comment on ``The application of the thermodynamic perturbation theory to study the hydrophobic hydration'' [J. Chem. Phys. 139, 024101 (2013)

NASA Astrophysics Data System (ADS)

Graziano, Giuseppe

2013-09-01

It is shown that the behaviour of the hydration thermodynamic functions obtained in the 3D Mercedes-Benz model of water by Mohoric et al. [J. Chem. Phys. 139, 024101 (2013)] is not qualitatively correct with respect to experimental data for a solute whose diameter is 1.5-fold larger than that of a water molecule. It is also pointed out that the failure is due to the fact that the used 3D Mercedes-Benz model of water [A. Bizjak, T. Urbic, V. Vlachy, and K. A. Dill, J. Chem. Phys. 131, 194504 (2009)] does not reproduce in a quantitatively correct manner the peculiar temperature dependence of water density.

Ligand Binding Analysis and Screening by Chemical Denaturation Shift

PubMed Central

Sch n, Arne; Brown, Richard K.; Hutchins, Burleigh M.; Freire, Ernesto

2013-01-01

The identification of small molecule ligands is an important first step in drug development, especially drugs that target proteins with no intrinsic activity. Towards this goal, it is important to have access to technologies that are able to measure binding affinities for a large number of potential ligands in a fast and accurate way. Since ligand binding stabilizes the protein structure in a manner dependent on concentration and binding affinity, the magnitude of the protein stabilization effect elicited by binding can be used to identify and characterize ligands. For example, the shift in protein denaturation temperature (Tm shift) has become a popular approach to identify potential ligands. However, Tm shifts cannot be readily transformed into binding affinities and the ligand rank order obtained at denaturation temperatures (60°C or higher) does not necessarily coincide with the rank order at physiological temperature. An alternative approach is the use of chemical denaturation, which can be implemented at any temperature. Chemical denaturation shifts allow accurate determination of binding affinities with a surprisingly wide dynamic range (high micromolar to sub nanomolar) and in situations in which binding changes the cooperativity of the unfolding transition. In this paper we develop the basic analytical equations and provide several experimental examples. PMID:23994566

Ligand binding analysis and screening by chemical denaturation shift.

PubMed

Schön, Arne; Brown, Richard K; Hutchins, Burleigh M; Freire, Ernesto

2013-12-01

The identification of small molecule ligands is an important first step in drug development, especially drugs that target proteins with no intrinsic activity. Toward this goal, it is important to have access to technologies that are able to measure binding affinities for a large number of potential ligands in a fast and accurate way. Because ligand binding stabilizes the protein structure in a manner dependent on concentration and binding affinity, the magnitude of the protein stabilization effect elicited by binding can be used to identify and characterize ligands. For example, the shift in protein denaturation temperature (Tm shift) has become a popular approach to identify potential ligands. However, Tm shifts cannot be readily transformed into binding affinities, and the ligand rank order obtained at denaturation temperatures (≥60°C) does not necessarily coincide with the rank order at physiological temperature. An alternative approach is the use of chemical denaturation, which can be implemented at any temperature. Chemical denaturation shifts allow accurate determination of binding affinities with a surprisingly wide dynamic range (high micromolar to sub nanomolar) and in situations where binding changes the cooperativity of the unfolding transition. In this article, we develop the basic analytical equations and provide several experimental examples. Copyright © 2013 Elsevier Inc. All rights reserved.

Ulex europaeus agglutinin II (UEA-II) is a novel, potent inhibitor of complement activation.

PubMed

Lekowski, R; Collard, C D; Reenstra, W R; Stahl, G L

2001-02-01

Complement is an important mediator of vascular injury following oxidative stress. We recently demonstrated that complement activation following endothelial oxidative stress is mediated by mannose-binding lectin (MBL) and activation of the lectin complement pathway. Here, we investigated whether nine plant lectins which have a binding profile similar to that of MBL competitively inhibit MBL deposition and subsequent complement activation following human umbilical vein endothelial cell (HUVEC) oxidative stress. HUVEC oxidative stress (1% O(2), 24 hr) significantly increased Ulex europaeus agglutinin II (UEA-II) binding by 72 +/- 9% compared to normoxic cells. UEA-II inhibited MBL binding to HUVEC in a concentration-dependent manner following oxidative stress. Further, MBL inhibited UEA-II binding to HUVEC in a concentration-dependent manner following oxidative stress, suggesting a common ligand. UEA-II (< or = 100 micromol/L) did not attenuate the hemolytic activity, nor did it inhibit C3a des Arg formation from alternative or classical complement pathway-specific hemolytic assays. C3 deposition (measured by ELISA) following HUVEC oxidative stress was inhibited by UEA-II in a concentration-dependent manner (IC(50) = 10 pmol/L). UEA-II inhibited C3 and MBL co-localization (confocal microscopy) in a concentration-dependent manner on HUVEC following oxidative stress (IC(50) approximately 1 pmol/L). Finally, UEA-II significantly inhibited complement-dependent neutrophil chemotaxis, but failed to inhibit fMLP-mediated chemotaxis, following endothelial oxidative stress. These data demonstrate that UEA-II is a novel, potent inhibitor of human MBL deposition and complement activation following human endothelial oxidative stress.

Ulex europaeus agglutinin II (UEA-II) is a novel, potent inhibitor of complement activation

PubMed Central

Lekowski, Robert; Collard, Charles D.; Reenstra, Wende R.; Stahl, Gregory L.

2001-01-01

Complement is an important mediator of vascular injury following oxidative stress. We recently demonstrated that complement activation following endothelial oxidative stress is mediated by mannose-binding lectin (MBL) and activation of the lectin complement pathway. Here, we investigated whether nine plant lectins which have a binding profile similar to that of MBL competitively inhibit MBL deposition and subsequent complement activation following human umbilical vein endothelial cell (HUVEC) oxidative stress. HUVEC oxidative stress (1% O2, 24 hr) significantly increased Ulex europaeus agglutinin II (UEA-II) binding by 72 ± 9% compared to normoxic cells. UEA-II inhibited MBL binding to HUVEC in a concentration-dependent manner following oxidative stress. Further, MBL inhibited UEA-II binding to HUVEC in a concentration-dependent manner following oxidative stress, suggesting a common ligand. UEA-II (≤ 100 μmol/L) did not attenuate the hemolytic activity, nor did it inhibit C3a des Arg formation from alternative or classical complement pathway-specific hemolytic assays. C3 deposition (measured by ELISA) following HUVEC oxidative stress was inhibited by UEA-II in a concentration-dependent manner (IC50 = 10 pmol/L). UEA-II inhibited C3 and MBL co-localization (confocal microscopy) in a concentration-dependent manner on HUVEC following oxidative stress (IC50 ≈ 1 pmol/L). Finally, UEA-II significantly inhibited complement-dependent neutrophil chemotaxis, but failed to inhibit fMLP-mediated chemotaxis, following endothelial oxidative stress. These data demonstrate that UEA-II is a novel, potent inhibitor of human MBL deposition and complement activation following human endothelial oxidative stress. PMID:11266613

41 CFR 102-74.185 - What heating and cooling policy must Federal agencies follow in Federal facilities?

Code of Federal Regulations, 2011 CFR

2011-01-01

... overall energy efficient and economical manner; (b) Maintain temperatures to maximize customer satisfaction by conforming to local commercial equivalent temperature levels and operating practices; (c) Set...-conditioning during non-working hours, except as necessary to return space temperatures to a suitable level for...

Two-Dimensional Ordering of Solute Nanoclusters at a Close-Packed Stacking Fault: Modeling and Experimental Analysis

PubMed Central

Kimizuka, Hajime; Kurokawa, Shu; Yamaguchi, Akihiro; Sakai, Akira; Ogata, Shigenobu

2014-01-01

Predicting the equilibrium ordered structures at internal interfaces, especially in the case of nanometer-scale chemical heterogeneities, is an ongoing challenge in materials science. In this study, we established an ab-initio coarse-grained modeling technique for describing the phase-like behavior of a close-packed stacking-fault-type interface containing solute nanoclusters, which undergo a two-dimensional disorder-order transition, depending on the temperature and composition. Notably, this approach can predict the two-dimensional medium-range ordering in the nanocluster arrays realized in Mg-based alloys, in a manner consistent with scanning tunneling microscopy-based measurements. We predicted that the repulsively interacting solute-cluster system undergoes a continuous evolution into a highly ordered densely packed morphology while maintaining a high degree of six-fold orientational order, which is attributable mainly to an entropic effect. The uncovered interaction-dependent ordering properties may be useful for the design of nanostructured materials utilizing the self-organization of two-dimensional nanocluster arrays in the close-packed interfaces. PMID:25471232

Binding mechanism of PicoGreen to DNA characterized by magnetic tweezers and fluorescence spectroscopy.

PubMed

Wang, Ying; Schellenberg, Helene; Walhorn, Volker; Toensing, Katja; Anselmetti, Dario

2017-09-01

Fluorescent dyes are broadly used in many biotechnological applications to detect and visualize DNA molecules. However, their binding to DNA alters the structural and nanomechanical properties of DNA and, thus, interferes with associated biological processes. In this work we employed magnetic tweezers and fluorescence spectroscopy to investigate the binding of PicoGreen to DNA at room temperature in a concentration-dependent manner. PicoGreen is an ultrasensitive quinolinium nucleic acid stain exhibiting hardly any background signal from unbound dye molecules. By means of stretching and overwinding single, torsionally constrained, nick-free double-stranded DNA molecules, we acquired force-extension and supercoiling curves which allow quantifying DNA contour length, persistence length and other thermodynamical binding parameters, respectively. The results of our magnetic tweezers single-molecule binding study were well supported through analyzing the fluorescent spectra of stained DNA. On the basis of our work, we could identify a concentration-dependent bimodal binding behavior, where, apparently, PicoGreen associates to DNA as an intercalator and minor-groove binder simultaneously.

Nelumbo nucifera leaves extracts inhibit mouse airway smooth muscle contraction.

PubMed

Yang, Xiao; Xue, Lu; Zhao, Qingyang; Cai, Congli; Liu, Qing-Hua; Shen, Jinhua

2017-03-20

Alkaloids extracted from lotus leaves (AELL) can relax vascular smooth muscle. However, whether AELL has a similar relaxant role on airway smooth muscle (ASM) remains unknown. This study aimed to explore the relaxant property of AELL on ASM and the underlying mechanism. Alkaloids were extracted from dried lotus leaves using the high temperature rotary evaporation extraction method. The effects of AELL on mouse ASM tension were studied using force measuring and patch-clamp techniques. It was found that AELL inhibited the high K + or acetylcholine chloride (ACh)-induced precontraction of mouse tracheal rings by 64.8 ± 2.9%, or 48.8 ± 4.7%, respectively. The inhibition was statistically significant and performed in a dose-dependent manner. Furthermore, AELL-induced smooth muscle relaxation was partially mediated by blocking voltage-dependent Ca 2+ channels (VDCC) and non-selective cation channels (NSCC). AELL, which plays a relaxant role in ASM, might be a new complementary treatment to treat abnormal contractions of the trachea and asthma.

Pb2+ Modulates Ca2+ Membrane Permeability In Paramecium

NASA Astrophysics Data System (ADS)

Bernal-Martínez, Juan; Ortega Soto, Arturo

2004-09-01

Intracellular recording experiments in current clamp configuration were done to evaluate whether Pb2+ modulates ionic membrane permeability in the fresh water Paramecium tetraurelia. It was found that Pb2+ triggers in a dose-dependent manner, a burst of spontaneous action potentials followed by a robust and sustained after hyper-polarization. In addition, Pb2+ increased the frequency of firing the spontaneous Ca2+-Action Potential and also, the duration of Ca2+-Action Potential, in a dose and reversibly-dependent manner. These results suggest that Pb2+ increases calcium membrane permeability of Paramecium and probably activates a calcium-dependent-potassium conductance in the ciliate.

Treponema pallidum 3-Phosphoglycerate Mutase Is a Heat-Labile Enzyme That May Limit the Maximum Growth Temperature for the Spirochete

PubMed Central

Benoit, Stéphane; Posey, James E.; Chenoweth, Matthew R.; Gherardini, Frank C.

2001-01-01

In the causative agent of syphilis, Treponema pallidum, the gene encoding 3-phosphoglycerate mutase, gpm, is part of a six-gene operon (tro operon) that is regulated by the Mn-dependent repressor TroR. Since substrate-level phosphorylation via the Embden-Meyerhof pathway is the principal way to generate ATP in T. pallidum and Gpm is a key enzyme in this pathway, Mn could exert a regulatory effect on central metabolism in this bacterium. To study this, T. pallidum gpm was cloned, Gpm was purified from Escherichia coli, and antiserum against the recombinant protein was raised. Immunoblots indicated that Gpm was expressed in freshly extracted infective T. pallidum. Enzyme assays indicated that Gpm did not require Mn2+ while 2,3-diphosphoglycerate (DPG) was required for maximum activity. Consistent with these observations, Mn did not copurify with Gpm. The purified Gpm was stable for more than 4 h at 25°C, retained only 50% activity after incubation for 20 min at 34°C or 10 min at 37°C, and was completely inactive after 10 min at 42°C. The temperature effect was attenuated when 1 mM DPG was added to the assay mixture. The recombinant Gpm from pSLB2 complemented E. coli strain PL225 (gpm) and restored growth on minimal glucose medium in a temperature-dependent manner. Increasing the temperature of cultures of E. coli PL225 harboring pSLB2 from 34 to 42°C resulted in a 7- to 11-h period in which no growth occurred (compared to wild-type E. coli). These data suggest that biochemical properties of Gpm could be one contributing factor to the heat sensitivity of T. pallidum. PMID:11466272

Non-isothermal electro-osmotic flow in a microchannel with charge-modulated surfaces

NASA Astrophysics Data System (ADS)

Bautista, Oscar; Sanchez, Salvador; Mendez, Federico

2015-11-01

In this work, we present an theoretical analysis of a nonisothermal electro-osmotic flow of a Newtonian fluid over charge-modulated surfaces in a microchannel. Here, the heating in the microchannel is due to the Joule effect caused by the imposition of an external electric field. The study is conducted through the use of perturbation techniques and is validated by means of numerical simulations. We consider that both, viscosity and electrical conductivity of the fluid are temperature-dependent; therefore, in order to determine the heat transfer process and the corresponding effects on the flow field, the governing equations of continuity, momentum, energy and electric potential have to be solved in a coupled manner. The principal obtained results evidence that the flow patterns are perturbed in a noticeable manner in comparison with the isothernal case. Our results may be used for increasing microfluidics mixing by conjugating thermal effects with the use of charge-modulated surfaces. This work has been supported by the research grants no. 220900 of Consejo Nacional de Ciencia y Tecnología (CONACYT) and 20150919 of SIP-IPN at Mexico. F. Méndez acknowledges also the economical support of PAPIIT-UNAM under contract number IN112215.

Symmetry control using beam phasing in ~0.2 NIF scale high temperature Hohlraum experiment on OMEGA

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

Delamater, Norman D; Wilson, Goug C; Kyrala, George A

2009-01-01

Results are shown from recent experiments at the Omega laser facility, using 40 Omega beams driving the hohlraum with 3 cones from each side and up to 19.5 kJ of laser energy. Beam phasing is achieved by decreasing the energy separately in each of the three cones, by 3 kJ, for a total drive energy of 16.5kJ. This results in a more asymmetric drive, which will vary the shape of the imploded symmetry capsule core from round to oblate or prolate in a systematic and controlled manner. These results would be the first demonstration of beam phasing for implosions inmore » such 'high temperature' (275 eV) hohlraums at Omega. Dante measurements confirmed the predicted peak drive temperatures of 275 eV. Implosion core time dependent x-ray images were obtained from framing camera data which show the expected change in symmetry due to beam phasing and which also agree well with post processed hydro code calculations. Time resolved hard x-ray data has been obtained and it was found that the hard x-rays are correlated mainly with the low angle 21{sup o} degree cone.« less

Aerobic function in mitochondria persists beyond death by heat stress in insects.

PubMed

Heinrich, Erica C; Gray, Emilie M; Ossher, Ashley; Meigher, Stephen; Grun, Felix; Bradley, Timothy J

2017-10-01

The critical thermal maximum (CT max ) of insects can be determined using flow-through thermolimit respirometry. It has been demonstrated that respiratory patterns cease and insects do not recover once the CT max temperature has been reached. However, if high temperatures are maintained following the CT max , researchers have observed a curious phenomenon whereby the insect body releases a large burst of carbon dioxide at a rate and magnitude that often exceed that of the live insect. This carbon dioxide release has been termed the post-mortal peak (PMP). We demonstrate here that the PMP is observed only at high temperatures, is oxygen-dependent, is prevented by cyanide exposure, and is associated with concomitant consumption of oxygen. We conclude that the PMP derives from highly active, aerobic metabolism in the mitochondria. The insect tracheal system contains air-filled tubes that reach deep into the tissues and allow mitochondria access to oxygen even upon organismal death. This unique condition permits the investigation of mitochondrial function during thermal failure in a manner that cannot be achieved using vertebrate organisms or in vitro preparations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth promotion effect of steelmaking slag on Spirulina platensis

NASA Astrophysics Data System (ADS)

Nogami, R.; Tam, L. T.; Anh, H. T. L.; Quynh, H. T. H.; Thom, L. T.; Nhat, P. V.; Thu, N. T. H.; Hong, D. D.; Wakisaka, M.

2016-04-01

A growth promotion effect of steelmaking slag on Spirulina platensis M135 was investigated. The growth promotion effect was obtained that was 1.27 times greater than that obtained by the control by adding 500 mg L-1 of steelmaking slag and culturing for 60 days. The lipid content decreased in a concentration-dependent manner with steelmaking slag, whereas the carbohydrate content remained constant. The protein content of S. platensis M135 increased in a concentration-dependent manner with steelmaking slag when cultured at day 45. The superoxide dismutase activity of S. platensis M135 exhibited a decreasing trend in a time-dependent manner and an increasing trend in the control. The superoxide dismutase activity was lower than that of the control at day 1 but was higher at day 30. No genetic damage was observed up to 500 mg L-1 of steelmaking slag at 30 days of culture. Recovery from genetic damage was observed at 1,000 mg L-1 of steelmaking slag but not at higher concentrations.

Geraniol attenuates α-synuclein expression and neuromuscular impairment through increase dopamine content in MPTP intoxicated mice by dose dependent manner.

PubMed

Rekha, Karamkolly R; Selvakumar, Govindasamy P; Santha, Karunanithi; Inmozhi Sivakamasundari, Ramu

2013-11-01

Parkinson's disease (PD) is characterized by progressive loss of dopamine (DA) neurons in the nigrostriatal system and by the presence of Lewy bodies (LB), proteinaceous inclusions mainly composed of filamentous α-synuclein (α-Syn) aggregates. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was adopted to generate PD models in C57BL/6 mice. In the present study, we investigated the effect of geraniol (GE) against α-Syn aggregation on MPTP induced mouse model of PD in dose dependant manner. When pretreatment of GE improved neuromuscular impairment, TH expressions and decreases α-Syn expressions in MPTP intoxicated PD mice by dose dependent manner. In addition, we confirmed that sub-chronic administration of MPTP in mice leads to permanent neuromuscular deficits and depletion of dopamine and its metabolites. Our results suggest that GE is beneficial for the treatment of PD associated with neuromuscular disability and LB aggregation. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

The readily releasable pool of vesicles in chromaffin cells is replenished in a temperature-dependent manner and transiently overfills at 37 degrees C.

PubMed

Dinkelacker, V; Voets, T; Neher, E; Moser, T

2000-11-15

Maturation of exocytic vesicles to the release-ready state is regulated by several factors, including intracellular calcium concentration ([Ca(2+)](int)) and the state of protein phosphorylation. Here we investigated the effects of temperature on the recovery from depletion of the readily releasable pool (RRP) of vesicles in adrenal chromaffin cells. Exocytosis and [Ca(2+)](int) were monitored by combined membrane capacitance and fura-2 measurements. At higher temperatures, a faster pool refilling and a larger RRP size were observed. The time constants of the recovery from depletion ranged from 3.6 to 1.1 sec (22 and 37 degrees C, respectively) yielding a Q(10) of 2.3. The changes of the Ca(2+) signal between the different temperatures could not account for the differences in recovery kinetics. At 32 and 37 degrees C, we observed a transient overfilling of the RRP after pool depletion, which stands in clear contrast to the sustained secretory depression seen at lower temperatures. The overshoot in RRP size was very prominent in cells with lower basal [Ca(2+)](int), hence with a large difference between prestimulus and poststimulus [Ca(2+)](int). In cells with higher basal [Ca(2+)](int), the pool was larger under steady-state conditions but showed less overfilling on stimulation. We conclude that vesicle maturation is markedly accelerated at physiological temperature, thus allowing for a rapid adaptation of the pool size to the relatively short-lived Ca(2+) transient.

Structural analysis of Ca²⁺ dependent and Ca²⁺ independent type II antifreeze proteins: a comparative molecular dynamics simulation study.

PubMed

Kundu, Sangeeta; Roy, Debjani

2012-09-01

Comparative molecular dynamics simulations of Ca²⁺ dependent psychrophilic type II antifreeze protein (AFP) from herring (Clupea harengus) (hAFP) and Ca²⁺ dependent type II antifreeze protein from long snout poacher (Brachyopsis rostratus) (lpAFP) have been performed for 10 ns each at five different temperatures. We have tried to investigate whether the Ca²⁺ dependent protein obtains any advantage in nature over the independent one. To this end the dynamic properties of these two proteins have been compared in terms of secondary structure content, molecular flexibility, solvent accessibility, intra molecular hydrogen bonds and protein-solvent interactions. At 298 and 373 K the flexibility of the Ca²⁺ independent molecule is higher which indicates that Ca²⁺ could contribute to stabilize the structure. The thermal unfolding pathways of the two proteins have also been monitored. The rate of unfolding is similar up to 373 K, beyond that hAFP shows faster unfolding than lpAFP. The essential subspaces explored by the simulations of hAFP and lpAFP at different temperatures are significantly different as revealed from principal component analysis. Our results may help in understanding the role of Ca²⁺ for hAFP to express antifreeze activity. Furthermore our study may also help in elucidating the molecular basis of thermostability of two structurally similar proteins, which perform the same function in different manner, one in presence of Ca²⁺, and the other in absence of the same. Copyright © 2012 Elsevier Inc. All rights reserved.

Explaining observed red and blue-shifts using multi-stranded coronal loops

NASA Astrophysics Data System (ADS)

Regnier, S.; Walsh, R. W.; Pearson, J.

2012-03-01

Magnetic plasma loops have been termed the building blocks of the solar atmosphere. However, it must be recognised that if the range of loop structures we can observe do consist of many ''sub-resolution'' elements, then current one-dimensional hydrodynamic models are really only applicable to an individual plasma element or strand. Thus a loop should be viewed is an amalgamation of these strands. They could operate in thermal isolation from one another with a wide range of temperatures occurring across the structural elements. This scenario could occur when the energy release mechanism consists of localised, discrete bursts of energy that are due to small scale reconnection sites within the coronal magnetic field- the nanoflare coronal heating mechanism. These energy bursts occur in a time-dependent manner, distributed along the loop/strand length, giving a heating function that depends on space and time. An important observational discovery with the Hinode/EIS spectrometer is the existence of red and blue-shifts in coronal loops depending on the location of the footpoints (inner or outer parts of the active region), and the temperature of the emission line in which the Doppler shifts are measured. Based on the multi-stranded model developed by Sarkar and Walsh (2008, ApJ, 683, 516), we show that red and blue-shifts exist in different simulated Hinode/EIS passbands: cooler lines (OV-SiVII) being dominated by red-shifts, whilst hotter lines (FeXV-CaXVII) are a combination of both. The distribution of blue-shifts depends on the energy input and not so much on the heating location. Characteristic Doppler shifts generated fit well with observed values. We also simulate the Hinode/EIS rasters to closely compare our simulation with the observations. Even if not statistically significant, loops can have footpoints with opposite Doppler shifts.

Environmental cold exposure increases blood flow and affects pain sensitivity in the knee joints of CFA-induced arthritic mice in a TRPA1-dependent manner.

PubMed

Fernandes, Elizabeth S; Russell, Fiona A; Alawi, Khadija M; Sand, Claire; Liang, Lihuan; Salamon, Robin; Bodkin, Jennifer V; Aubdool, Aisah A; Arno, Matthew; Gentry, Clive; Smillie, Sarah-Jane; Bevan, Stuart; Keeble, Julie E; Malcangio, Marzia; Brain, Susan D

2016-01-11

The effect of cold temperature on arthritis symptoms is unclear. The aim of this study was to investigate how environmental cold affects pain and blood flow in mono-arthritic mice, and examine a role for transient receptor potential ankyrin 1 (TRPA1), a ligand-gated cation channel that can act as a cold sensor. Mono-arthritis was induced by unilateral intra-articular injection of complete Freund's adjuvant (CFA) in CD1 mice, and in mice either lacking TRPA1 (TRPA1 KO) or respective wildtypes (WT). Two weeks later, nociception and joint blood flow were measured following exposure to 10 °C (1 h) or room temperature (RT). Primary mechanical hyperalgesia in the knee was measured by pressure application apparatus; secondary mechanical hyperalgesia by automated von Frey system; thermal hyperalgesia by Hargreaves technique, and weight bearing by the incapacitance test. Joint blood flow was recorded by full-field laser perfusion imager (FLPI) and using clearance of (99m)Technetium. Blood flow was assessed after pretreatment with antagonists of either TRPA1 (HC-030031), substance P neurokinin 1 (NK1) receptors (SR140333) or calcitonin gene-related peptide (CGRP) (CGRP8-37). TRPA1, TAC-1 and CGRP mRNA levels were examined in dorsal root ganglia, synovial membrane and patellar cartilage samples. Cold exposure caused bilateral primary mechanical hyperalgesia 2 weeks after CFA injection, in a TRPA1-dependent manner. In animals maintained at RT, clearance techniques and FLPI showed that CFA-treated joints exhibited lower blood flow than saline-treated joints. In cold-exposed animals, this reduction in blood flow disappears, and increased blood flow in the CFA-treated joint is observed using FLPI. Cold-induced increased blood flow in CFA-treated joints was blocked by HC-030031 and not observed in TRPA1 KOs. Cold exposure increased TRPA1 mRNA levels in patellar cartilage, whilst reducing it in synovial membranes from CFA-treated joints. We provide evidence that environmental cold exposure enhances pain and increases blood flow in a mono-arthritis model. These changes are dependent on TRPA1. Thus, TRPA1 may act locally within the joint to influence blood flow via sensory nerves, in addition to its established nociceptive actions.

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

Onopiuk, Marta; Wierzbicka, Katarzyna; Brutkowski, Wojciech

Activation of T-cells triggers store-operated Ca{sup 2+} entry, which begins a signaling cascade leading to induction of appropriate gene expression and eventually lymphocyte proliferation and differentiation. The simultaneous enhancement of Fas ligand gene expression in activated cells allows the immune response to be limited by committing the activated cells to apoptosis. In apoptotic cells the store-operated calcium entry is significantly inhibited. It has been documented that moderate activation of Fas receptor may cause reversible inhibition of store-operated channels by ceramide released from hydrolyzed sphingomyelin. Here we show that activation of Fas receptor in T-cells results in caspase-dependent decrease of cellularmore » STIM1 and Orai1 protein content. This effect may be responsible for the substantial inhibition of Ca{sup 2+} entry into Jurkat cells undergoing apoptosis. In turn, this inhibition might prevent overloading of cells with calcium and protect them against necrosis. -- Research highlights: {yields} Fas activation reduces STIM1 and Orai1 protein content in caspase dependent manner. {yields} Fas activation partially reduces mitochondrial potential in caspase dependent manner. {yields} Fas stimulation inhibits of store-operated Ca{sup 2+} entry in caspase dependent manner. {yields} Inhibition of Ca{sup 2+} entry in apoptotic cells may protect them from secondary necrosis.« less

Nanoscale steady-state temperature gradients within polymer nanocomposites undergoing continuous-wave photothermal heating from gold nanorods.

PubMed

Maity, Somsubhra; Wu, Wei-Chen; Tracy, Joseph B; Clarke, Laura I; Bochinski, Jason R

2017-08-17

Anisotropically-shaped metal nanoparticles act as nanoscale heaters via excitation of a localized surface plasmon resonance, utilizing a photothermal effect which converts the optical energy into local heat. Steady-state temperatures within a polymer matrix embedded with gold nanorods undergoing photothermal heating using continuous-wave excitation are measured in the immediate spatial vicinity of the nanoparticle (referred to as the local temperature) from observing the rate of physical rotation of the asymmetric nanoparticles within the locally created polymer melt. Average temperatures across the entire (mostly solid) sample (referred to as the global temperature) are simultaneously observed using a fluorescence method from randomly dispersed molecular emitters. Comparing these two independent measurements in films having varying concentrations of nanorods reveals the interplay between the local and global temperatures, clearly demonstrating the capability of these material samples to sustain large steady-state spatial temperature gradients when experiencing continuous-wave excitation photothermal heating. These results are discussed quantitatively. Illustrative imaging studies of nanofibers under photothermal heating also support the presence of a large temperature gradient. Photothermal heating in this manner has potential utility in creating unique thermal processing conditions for outcomes such as driving chemical reactions, inducing crystallinity changes, or enhancing degradation processes in a manner unachievable by conventional heating methods.

Rethinking cell-cycle-dependent gene expression in Schizosaccharomyces pombe.

PubMed

Cooper, Stephen

2017-11-01

Three studies of gene expression during the division cycle of Schizosaccharomyces pombe led to the proposal that a large number of genes are expressed at particular times during the S. pombe cell cycle. Yet only a small fraction of genes proposed to be expressed in a cell-cycle-dependent manner are reproducible in all three published studies. In addition to reproducibility problems, questions about expression amplitudes, cell-cycle timing of expression, synchronization artifacts, and the problem with methods for synchronizing cells must be considered. These problems and complications prompt the idea that caution should be used before accepting the conclusion that there are a large number of genes expressed in a cell-cycle-dependent manner in S. pombe.

A timecourse analysis of systemic and gonadal effects of temperature on sexual development of the red-eared slider turtle Trachemys scripta elegans.

PubMed

Czerwinski, Michael; Natarajan, Anirudh; Barske, Lindsey; Looger, Loren L; Capel, Blanche

2016-12-01

Temperature dependent sex determination (TSD) is the process by which the environmental temperature experienced during embryogenesis influences the sex of an organism, as in the red-eared slider turtle Trachemys scripta elegans. In accord with current paradigms of vertebrate sex determination, temperature is believed to exert its effects on sexual development in T. scripta entirely within the middle third of development, when the gonad is forming. However, whether temperature regulates the transcriptome in T. scripta early embryos in a manner that could influence secondary sex characteristics or establish a pro-male or pro-female environment has not been investigated. In addition, apart from a handful of candidate genes, very little is known about potential similarities between the expression cascade during TSD and the genetic cascade that drives mammalian sex determination. Here, we conducted an unbiased transcriptome-wide analysis of the effects of male- and female-promoting temperatures on the turtle embryo prior to gonad formation, and on the gonad during the temperature sensitive period. We found sexually dimorphic expression reflecting differences in steroidogenic enzymes and brain development prior to gonad formation. Within the gonad, we mapped a cascade of differential expression similar to the genetic cascade established in mammals. Using a Hidden Markov Model based clustering approach, we identified groups of genes that show heterochronic shifts between M. musculus and T. scripta. We propose a model in which multiple factors influenced by temperature accumulate during early gonadogenesis, and converge on the antagonistic regulation of aromatase to canalize sex determination near the end of the temperature sensitive window of development. Copyright © 2016 Elsevier Inc. All rights reserved.

Seasonal photosynthetic responses of European oaks to drought and elevated daytime temperature.

PubMed

Arend, M; Brem, A; Kuster, T M; Günthardt-Goerg, M S

2013-01-01

Oaks are commonly considered as drought- and heat-tolerant trees that might benefit from a warmer and drier climate. Their tolerance to drought has been frequently studied in the past, whereas studies dealing with elevated temperature or its combination with drought are very limited in number. In this study we investigated seasonal photosynthetic patterns in three European oak species (Quercus robur, Q. petraea, Q. pubescens) exposed in lysimeter-based open-top chambers (OTC) to elevated daytime temperature, drought and their combination. Stomatal and non-stomatal traits of photosynthesis were followed over an entire growing season and related to changes in daytime temperature, soil moisture and pre-dawn leaf water potential (Ψ(PD) ). Elevated daytime temperature enhanced net photosynthesis (P(N) ) in a season-dependent manner, with higher mid-summer rates than in controls exposed to ambient temperature. Drought imposed in early and mid-summer reduced the soil moisture content and caused a gradual decline in Ψ(PD) , stomatal conductance (g(S) ) and P(N) . Drought effects on Ψ(PD) and P(N) were exacerbated when drought was combined with elevated daytime temperature. In general, P(N) tended to be more affected by low soil moisture content or low Ψ(PD) in Q. robur than in Q. petraea and Q. pubescens. Non-stomatal limitations may have contributed to the drought-induced decline of P(N) in Q. robur, as indicated by a down-regulation of PSII photochemistry (F(V) /F(M) ) and decreased chlorophyll content. Taken together, our findings show that European oaks may benefit from elevated temperature, but detrimental effects can be expected when elevated temperature occurs simultaneously with drought. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effect of temperature on life history parameters of adult Culicoides sonorensis (Diptera: Ceratopogonidae) in relation to geographic origin and vectorial capacity for bluetongue virus.

PubMed

Lysyk, T J; Danyk, T

2007-09-01

The effect of temperature on survival, oviposition, gonotrophic development, and a life history factor of vectorial capacity were examined in adult Culicoides sonorensis (Wirth & Jones) (Diptera: Ceratopogonidae) that originated from two geographic locations. Flies originating from the United States (Colorado) had slightly reduced survival after a bloodmeal compared with wild flies collected in southern Alberta (AB), Canada. Survival of AB flies declined in a curvilinear manner with temperature, whereas survival of U.S. flies showed a linear response to temperature. The survivorship curve of the AB flies more closely followed a Weibull distribution than an exponential, indicating survival was age-dependent. Survivorship of the U.S. flies followed an exponential distribution. Females from both sources laid similar numbers of eggs throughout their life. The first eggs were laid by females from both sources at 31.9 degree-day (DD)9.3. Dissections of blood-fed flies reared at various temperatures indicated that flies from both sources were 90% gravid at 32 DD9.3. Relationships among temperature and life history components of vectorial capacity were similar among flies from the two sources and indicated that vectorial capacity would be approximately 1.8-2.6-fold greater in a southern U.S. climate compared with southwestern Canada due solely to the effects of temperature on the life history of C. sonorensis. Using life history estimates derived from Weibull model had little effect on estimating vectorial capacity, whereas using estimates derived from the exponential model slightly overestimated vectorial capacity.

Mechanical properties and fractal analysis of the surface texture of sputtered hydroxyapatite coatings

NASA Astrophysics Data System (ADS)

Bramowicz, Miroslaw; Braic, Laurentiu; Azem, Funda Ak; Kulesza, Slawomir; Birlik, Isil; Vladescu, Alina

2016-08-01

This aim of this work is to establish a relationship between the surface morphology and mechanical properties of hydroxyapatite coatings prepared using RF magnetron sputtering at temperatures in the range from 400 to 800 °C. The topography of the samples was scanned using atomic force microscopy, and the obtained 3D maps were analyzed using fractal methods to derive the spatial characteristics of the surfaces. X-ray photoelectron spectroscopy revealed the strong influence of the deposition temperature on the Ca/P ratio in the growing films. The coatings deposited at 600-800 °C exhibited a Ca/P ratio between 1.63 and 1.69, close to the stoichiometric hydroxyapatite (Ca/P = 1.67), which is crucial for proper osseointegration. Fourier-transform infrared spectroscopy showed that the intensity of phosphate absorption bands increased with increasing substrate temperature. Each sample exhibited well defined and sharp hydroxyapatite band at 566 cm-1, although more pronounced for the coatings deposited above 500 °C. Both the hardness and elastic modulus of the coated samples decrease with increasing deposition temperature. The surface morphology strongly depends on the deposition temperature. The sample deposited at 400 °C exhibits circular cavities dug in an otherwise flat surface. At higher deposition temperatures, these cavities increase in size and start to overlap each other so that at 500 °C the surface is composed of closely packed peaks and ridges. At that point, the characteristics of the surface turns from the dominance of cavities to grains of similar size, and develops in a similar manner at higher temperatures.

Inhibition of Estrogen-Induced Growth of Breast Cancer by Targeting Mitrochondrial Oxidants

DTIC Science & Technology

2007-04-01

expected estradiol induced oxidants production in MCF-7 cells in dose dependent manner (Fig. 1). 0 50 100 150 200 250 300 DMSO 100pg 10ng 100ng...dose dependent manner. This is in agreement with previous findings (Foster et al., 2001). 0 50 100 150 200 250 300 DMSO 100pg/ml 10ng/ml 100ng/ml C...significantly inhibited E2-induced cell growth by as much as 50 % after a 72 h treatment. The reduction of E2-induced cell growth observed with NAC and

Simulation of Crack Propagation in Engine Rotating Components under Variable Amplitude Loading

NASA Technical Reports Server (NTRS)

Bonacuse, P. J.; Ghosn, L. J.; Telesman, J.; Calomino, A. M.; Kantzos, P.

1998-01-01

The crack propagation life of tested specimens has been repeatedly shown to strongly depend on the loading history. Overloads and extended stress holds at temperature can either retard or accelerate the crack growth rate. Therefore, to accurately predict the crack propagation life of an actual component, it is essential to approximate the true loading history. In military rotorcraft engine applications, the loading profile (stress amplitudes, temperature, and number of excursions) can vary significantly depending on the type of mission flown. To accurately assess the durability of a fleet of engines, the crack propagation life distribution of a specific component should account for the variability in the missions performed (proportion of missions flown and sequence). In this report, analytical and experimental studies are described that calibrate/validate the crack propagation prediction capability ]or a disk alloy under variable amplitude loading. A crack closure based model was adopted to analytically predict the load interaction effects. Furthermore, a methodology has been developed to realistically simulate the actual mission mix loading on a fleet of engines over their lifetime. A sequence of missions is randomly selected and the number of repeats of each mission in the sequence is determined assuming a Poisson distributed random variable with a given mean occurrence rate. Multiple realizations of random mission histories are generated in this manner and are used to produce stress, temperature, and time points for fracture mechanics calculations. The result is a cumulative distribution of crack propagation lives for a given, life limiting, component location. This information can be used to determine a safe retirement life or inspection interval for the given location.

Ultrathin Injectable Sensors of Temperature, Thermal Conductivity, and Heat Capacity for Cardiac Ablation Monitoring.

PubMed

Koh, Ahyeon; Gutbrod, Sarah R; Meyers, Jason D; Lu, Chaofeng; Webb, Richard Chad; Shin, Gunchul; Li, Yuhang; Kang, Seung-Kyun; Huang, Yonggang; Efimov, Igor R; Rogers, John A

2016-02-04

Knowledge of the distributions of temperature in cardiac tissue during and after ablation is important in advancing a basic understanding of this process, and for improving its efficacy in treating arrhythmias. Technologies that enable real-time temperature detection and thermal characterization in the transmural direction can help to predict the depths and sizes of lesion that form. Herein, materials and designs for an injectable device platform that supports precision sensors of temperature and thermal transport properties distributed along the length of an ultrathin and flexible needle-type polymer substrate are introduced. The resulting system can insert into the myocardial tissue, in a minimally invasive manner, to monitor both radiofrequency ablation and cryoablation, in a manner that has no measurable effects on the natural mechanical motions of the heart. The measurement results exhibit excellent agreement with thermal simulations, thereby providing improved insights into lesion transmurality. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization and antioxidant activities of marine pepsin soluble collagen from the skin of yellow goosefish Lophius litulon

NASA Astrophysics Data System (ADS)

Zheng, Bin; Xiang, Xingwei; Zhou, Yufang; Yang, Huicheng; Luo, Hongyu; Liao, Miaofei; Wen, Zhengshun

2017-05-01

Characteristics and antioxidant activities of pepsin-soluble collagen (PSC) from yellow goosefish ( Lophius litulon) skins were investigated. PSC was characterized as a type I collagen, and its imino acid content was 193 residues/1 000 residues. PSC's denaturation temperature was 17.56°C and Fourier transform infrared spectra confirmed the presence of triple helices. Solubility analysis showed good solubility at acidic pH (1-6) or low NaCl concentrations (≤2%). PSC showed scavenging activity against hydroxyl radicals and superoxide anions in a concentration-dependent manner. Furthermore, PSC could protect D-galactose-induced skin aging by significantly controlling malondialdehyde formation and improving the activity of superoxide dismutase, glutathione peroxidase, catalase, glutathione, and hydroxyproline. PSC may be a promising antioxidant in appropriate applications.

OPERATIONAL CHARACTERISTICS OF THE ARMOUR FISSION GAS GAMMA FACILITY

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

Terrell, C.W.; McElroy, W.N.

1958-10-31

As the reactor power level is changed frequently, the radiation levels in the gamma facility fluctuate. Data are presented to show the power dependency of the gamma dose rate and the manner of growth and decay. Additional data show the dependercy of the equilibrium gamma activity on the foel temperature and total system pressure. The final phase of the work is directed toward determining an average gamma energy by attenuation measurements with various thicknesses of several materials. The neutrou flux associated with the gas phase activity is determined by foil measurement. From the measurements of dose rate and average gammamore » energy, calculations to determine the number of curies of gas phase decay gamma activity per watt of reactor power are presented. (auth)« less

Seasonal and inter-annual variation in ecosystem scale methane emission from a boreal fen

NASA Astrophysics Data System (ADS)

Rinne, Janne; Li, Xuefei; Raivonen, Maarit; Peltola, Olli; Sallantaus, Tapani; Haapanala, Sami; Smolander, Sampo; Alekseychik, Pavel; Aurela, Mika; Korrensalo, Aino; Mammarella, Ivan; Tuittila, Eeva-Stiina; Vesala, Timo

2016-04-01

Northern wetlands are one of the major sources of atmospheric methane. We have measured ecosystem scale methane emissions from a boreal fen continuously since 2005. The site is an oligotrophic fen in boreal vegetation zone situated in Siikaneva wetland complex in Southern Finland. The mean annual temperature in the area is 3.3°C and total annual precipitation 710 mm. We have conducted the methane emission measurements by the eddy covariance method. Additionally we have measured fluxes of carbon dioxide, water vapor, and sensible heat together with a suite of other environmental parameters. We have analyzed this data alongside with a model run with University of Helsinki methane model. The measured fluxes show generally highest methane emission in late summers coinciding with the highest temperatures in saturated peat zone. During winters the fluxes show small but detectable emission despite the snow and ice cover on the fen. More than 90% of the annual methane emission occurs in snow-free period. The methane emission and peat temperature are connected in exponential manner in seasonal scales, but methane emission does not show the expected behavior with water table. The lack of water table position dependence also contrasts with the spatial variation across microtopography. There is no systematic variation in sub-diurnal time scale. The general seasonal cycle in methane emission is captured well with the methane model. We will show how well the model reproduces the temperature and water table position dependencies observed. The annual methane emission is typically around 10 gC m-2. This is a significant part of the total carbon exchange between the fen and the atmosphere and about twice the estimated carbon loss by leaching from the fen area. The inter-annual variability in the methane emission is modest. The June-September methane emissions from different years, comprising most of the annual emission, correlates positively with peat temperature, but not with water table position.

Temperature measurement method using temperature coefficient timing for resistive or capacitive sensors

DOEpatents

Britton, Jr., Charles L.; Ericson, M. Nance

1999-01-01

A method and apparatus for temperature measurement especially suited for low cost, low power, moderate accuracy implementation. It uses a sensor whose resistance varies in a known manner, either linearly or nonlinearly, with temperature, and produces a digital output which is proportional to the temperature of the sensor. The method is based on performing a zero-crossing time measurement of a step input signal that is double differentiated using two differentiators functioning as respective first and second time constants; one temperature stable, and the other varying with the sensor temperature.

The Sleep-Promoting and Hypothermic Effects of Glycine are Mediated by NMDA Receptors in the Suprachiasmatic Nucleus

PubMed Central

Kawai, Nobuhiro; Sakai, Noriaki; Okuro, Masashi; Karakawa, Sachie; Tsuneyoshi, Yosuke; Kawasaki, Noriko; Takeda, Tomoko; Bannai, Makoto; Nishino, Seiji

2015-01-01

The use of glycine as a therapeutic option for improving sleep quality is a novel and safe approach. However, despite clinical evidence of its efficacy, the details of its mechanism remain poorly understood. In this study, we investigated the site of action and sleep-promoting mechanisms of glycine in rats. In acute sleep disturbance, oral administration of glycine-induced non-rapid eye movement (REM) sleep and shortened NREM sleep latency with a simultaneous decrease in core temperature. Oral and intracerebroventricular injection of glycine elevated cutaneous blood flow (CBF) at the plantar surface in a dose-dependent manner, resulting in heat loss. Pretreatment with N-methyl-D-aspartate (NMDA) receptor antagonists AP5 and CGP78608 but not the glycine receptor antagonist strychnine inhibited the CBF increase caused by glycine injection into the brain. Induction of c-Fos expression was observed in the hypothalamic nuclei, including the medial preoptic area (MPO) and the suprachiasmatic nucleus (SCN) shell after glycine administration. Bilateral microinjection of glycine into the SCN elevated CBF in a dose-dependent manner, whereas no effect was observed when glycine was injected into the MPO and dorsal subparaventricular zone. In addition, microinjection of D-serine into the SCN also increased CBF, whereas these effects were blocked in the presence of L-701324. SCN ablation completely abolished the sleep-promoting and hypothermic effects of glycine. These data suggest that exogenous glycine promotes sleep via peripheral vasodilatation through the activation of NMDA receptors in the SCN shell. PMID:25533534

Altered pharmacology of native rodent spinal cord TRPV1 after phosphorylation

PubMed Central

Mogg, AJ; Mill, CEJ; Folly, EA; Beattie, RE; Blanco, MJ; Beck, JP; Broad, LM

2013-01-01

Background and Purpose Evidence suggests that phosphorylation of TRPV1 is an important component underlying its aberrant activation in pathological pain states. To date, the detailed pharmacology of diverse TRPV1 receptor agonists and antagonists has yet to be reported for native TRPV1 under phosphorylating conditions. Our goal was to optimize a relatively high-throughput methodology to allow pharmacological characterization of the native TRPV1 receptor using a spinal cord neuropeptide release assay under naive and phosphorylating states. Experimental Approach Herein, we describe characterization of rodent TRPV1 by measurement of CGRP release from acutely isolated lumbar (L1-L6) spinal cord using a 96-well technique that combines use of native, adult tissue with quantitation of CGRP release by elisa. Key Results We have studied a diverse panel of TRPV1 agonists and antagonists under basal and phosphorylating conditions. We show that TRPV1-mediated CGRP release is evoked, in a temperature-dependent manner, by a PKC activator, phorbol 12,13-dibutyrate (PDBu); and that treatment with PDBu increases the potency and efficacy of known TRPV1 chemical agonists, in an agonist-specific manner. We also show that the pharmacological profile of diverse TRPV1 antagonists is dependent on whether the stimulus is PDBu or capsaicin. Of note, HPPB was identified as an antagonist of capsaicin-evoked, but a potentiator of PDBu-evoked, CGRP release. Conclusions and Implications Our findings indicate that both TRPV1 agonist and antagonist profiles can be differentially altered by PKC activation. These findings may offer new insights for targeting TRPV1 in pain states. PMID:23062150

Association Between Fungal Contamination and Eye Bank-Prepared Endothelial Keratoplasty Tissue: Temperature-Dependent Risk Factors and Antifungal Supplementation of Optisol-Gentamicin and Streptomycin.

PubMed

Brothers, Kimberly M; Shanks, Robert M Q; Hurlbert, Susan; Kowalski, Regis P; Tu, Elmer Y

2017-11-01

Fungal contamination and infection from donor tissues processed for endothelial keratoplasty is a growing concern, prompting analysis of donor tissues after processing. To determine whether eyebank-processed endothelial keratoplasty tissue is at higher risk of contamination than unprocessed tissue and to model eyebank processing with regard to room temperature exposure on Candida growth in optisol-gentamicin and streptomycin (GS) with and without antifungal supplementation. An examination of the 2013 Eversight Eyebank Study follow-up database for risk factors associated with post-keratoplasty infection identified an increased risk of positive fungal rim culture results in tissue processed for endothelial keratoplasty vs unprocessed tissue. Processing steps at room temperature were hypothesized as a potential risk factor for promotion of fungal growth between these 2 processes. Candida albicans, Candida glabrata, and Candida parapsilosis endophthalmitis isolates were each inoculated into optisol-GS and subjected to 2 different room temperature incubation regimens reflective of current corneal tissue handling protocols. Eversight Eyebank Study outcomes and measures were follow-up inquiries from 6592 corneal transplants. Efficacy study outcomes and measures were fungal colony-forming units from inoculated vials of optisol-GS taken at 2 different processing temperatures. Donor rim culture results were 3 times more likely to be positive for fungi in endothelial keratoplasty-processed eyes (1.14%) than for other uses (0.37%) (difference, 0.77%; 95% CI, 0.17-.1.37) (P = .009). In vitro, increased room temperature incubation of optisol-GS increased growth of Candida species over time. The addition of caspofungin and voriconazole decreased growth of Candida in a species-dependent manner. Detectable Candida growth in donor rim cultures, associated with a higher rate of post keratoplasty infection, is seen in endothelial keratoplasty tissue vs other uses at the time of transplantation, likely owing in part to eyebank preparation processes extending the time of tissue warming. Reduced room temperature incubation and the addition of antifungal agents decreased growth of Candida species in optisol-GS and should be further explored to reduce the risk of infection.

Elevated temperature strain gages

NASA Technical Reports Server (NTRS)

Brittain, J. O.; Geslin, D.; Lei, J. F.

1985-01-01

Materials were evaluated that could be used in manufacturing electrical resistance strain gages for static strain measurements at temperatures at or above 1273 K. Strain gage materials must have a characteristic response to strain, temperature and time that is reproducible or that varies in a predictable manner within specified limits. Several metallic alloys were evaluated, as well as a series of transition metal carbides, nitrides and silicides.

A forskolin derivative, colforsin daropate hydrochloride, inhibits rat mesangial cell mitogenesis via the cyclic AMP pathway.

PubMed

Ogata, Junichi; Minami, Kouichiro; Segawa, Kayoko; Yamamoto, Chieko; Kim, Sung-Teh; Shigematsu, Akio

2003-11-01

A forskolin derivative, colforsin daropate hydrochloride (CDH), has been introduced as an inotropic agent that acts directly on adenylate cyclase to increase intracellular cyclic AMP (cAMP) levels and ventricular contractility, resulting in positive inotropic activity. We investigated the effects of CDH on rat mesangial cell (MC) proliferation. CDH (10(-7)-10(-5) mol/l) inhibited [(3)H]thymidine incorporation into cultured rat MCs in a concentration-dependent manner. CDH (10(-7)-10(-5) mol/l) also decreased cell numbers in a similar manner, and stimulated cAMP accumulation in MCs in a concentration-dependent manner. A protein kinase A inhibitor, H-89, abolished the inhibitory effects of CDH on MC mitogenesis. These findings suggest that CDH would inhibit the proliferation of rat MCs via the cAMP pathway. Copyright 2003 S. Karger AG, Basel

Antioxidant activities of saponins extracted from Radix Trichosanthis: an in vivo and in vitro evaluation

PubMed Central

2014-01-01

Background Radix Trichosanthis (RT), the dry root tuber of Trichosanthis kirilowii Maxim (Cucurbitaceae), is a traditional Chinese medicine. Although a wide range of saponin pharmacological properties has been identified, to our knowledge, this may be the first report to investigate the crude saponins from RT. The purpose of this study was to delineate the antioxidant activity both in vitro and in vivo by using ethyl acetate (EtOAc), n-butanol, and the mixture of n-butanol and EtOAc fractions. Methods In vitro antioxidant activity was detected by using DPPH free radical, hydrogen peroxide scavenging, and reducing power assays. After pretreatment with different fractions saponins at 2 mg/kg/d and 3 mg/kg/d of crude drug, respectively, an established CCl4 induced acute cytotoxicity model was used to evaluate the in vivo antioxidant potential by detection of superoxide dismutase (SOD), malonaldehyde (MDA), lactate dehydrogenase (LDH), and total antioxidant capacity (T-AOC) levels. Results The in vitro assay showed that the antioxidant activity of all the three fractions was promising. The reducing power of the EtOAc and the mixture of n-butanol and EtOAc extracts increased in a dose dependent manner. However, both the n-butanol and the mixture of n-butanol and EtOAc fractions in low dose exhibited in a time dependent manner with prolonged reaction time. As for hydrogen peroxide scavenging capability, the n-butanol fraction mainly demonstrated a time dependent manner, whereas EtOAc fraction showed a dose dependent manner. However, in case of in vivo assay, an increase of SOD and T-AOC and decrease of MDA and LDH levels were only observed in n-butanol (2 mg/kg/d of crude drug) extracts pretreatment group. Conclusions RT saponins in n-butanol fraction might be a potential antioxidant candidate, as CCl4-induced oxidative stress has been found to be alleviated, which may be associated with the time dependent manner of n-butanol saponins in a low dose. Further studies will be needed to investigate the active individual components in n-butanol extract, in vivo antioxidant activities and antioxidant mechanisms. PMID:24597831

Quasiparticle properties at microwave frequencies in the underdoped YBa2Cu3O7-δ thin films

NASA Astrophysics Data System (ADS)

Hsing, Lai

2004-03-01

Microstrip ring resonators with quality factor (Q) over 10^4 at temperature 5 K were fabricated using the double-side YBa_2Cu_3O_7-δ (YBCO) films deposited on LaAlO3 (LAO) substrates. By placing a narrow gap in the ring resonator, the original fundamental resonating mode (3.61 GHz) splits into two modes (1.80 GHz and 5.33 GHz) with distinct resonating frequencies. The samples allow us to determine the temperature and the frequency dependences of penetration depth and microwave conductivity for various underdoped-cuprates by using Drude formula and the modified two-fluid model. The natures of the order parameter of high-Tc superconductivity in the underdoped cases are shown to be of d-wave type in an exact manner. In particular, the Fermi-liquid correction factor α ^2 and the vertex correction factor β from the model, proposed by Wen and Lee, can be estimated that α ^2 is doping independent in the underdoped regime and β decreases as oxygen content is decreasing in our experiment data. All these results are independent of frequencies as well. The results reveal that the interaction between quasiparticles is insensitive dependence of the impurity concentrations due to oxygen deficiency on the CuO chain and the impurity potential for forward scattering approaches the same as back scattering with more oxygen deficiency.

CD86 and beta2-adrenergic receptor signaling pathways, respectively, increase Oct-2 and OCA-B Expression and binding to the 3'-IgH enhancer in B cells.

PubMed

Podojil, Joseph R; Kin, Nicholas W; Sanders, Virginia M

2004-05-28

Stimulation of CD86 (formerly known as B7-2) and/or the beta2-adrenergic receptor on a CD40 ligand/interleukin-4-activated B cell increased the rate of mature IgG1 transcription. To identify the mechanism responsible for this effect, we determined whether CD86 and/or beta2-adrenergic receptor stimulation regulated transcription factor expression and binding to the 3'-IgH enhancer in vitro and in vivo. We showed that CD86 stimulation increased the nuclear localization of NF-kappaB1 (p50) and phosphorylated RelA (p65) and increased Oct-2 expression and binding to the 3'-IgH enhancer, in a protein kinase C-dependent manner. These effects were lost when CD86-deficient or NF-kappaB1-deficient B cells were used. CD86 stimulation also increased the level of IkappaB-alpha phosphorylation but in a protein kinase C-independent manner. Beta2-adrenergic receptor stimulation increased CREB phosphorylation, OCA-B expression, and OCA-B binding to the 3'-IgH enhancer in a protein kinase A-dependent manner, an effect lost when beta2-adrenergic receptor-deficient B cells were used. Also, the beta2-adrenergic receptor-induced increase in the level of mature IgG1 transcript was lost when OCA-B-deficient B cells were used. These data are the first to show that CD86 stimulation up-regulates the expression of the transcription factor Oct-2 in a protein kinase C- and NF-kappaB1-dependent manner, and that beta2-adrenergic receptor stimulation up-regulates the expression of the coactivator OCA-B in a protein kinase A-dependent manner to cooperate with Oct-2 binding to the 3'-IgH enhancer.

Evidence for a possible neurotransmitter/neuromodulator role of tyramine on the locust oviducts.

PubMed

Donini, Andrew; Lange, Angela B

2004-04-01

Visualization of the tyraminergic innervation of the oviducts was demonstrated by immunohistochemistry, and the presence of tyramine was confirmed using high-performance liquid chromatography coupled to electrochemical detection. Oviducts incubated in high-potassium saline released tyramine in a calcium-dependent manner. Stimulation of the oviducal nerves also resulted in tyramine release, suggesting that tyramine might function as a neurotransmitter/neuromodulator at the locust oviducts. Tyramine decreased the basal tension, and also attenuated proctolin-induced contractions in a dose-dependent manner over a range of doses between 10(-7) and 10(-4) M. Low concentrations of tyramine attenuated forskolin-stimulated cyclic AMP levels in a dose-dependent manner. This effect was not blocked by yohimbine. High concentrations of tyramine increased basal cyclic AMP levels of locust oviducts in a dose-dependent manner; however, the increases in cyclic AMP were only evident at the highest concentrations tested, 5 x 10(-5) and 10(-4) M tyramine. The tyramine-induced increase in cyclic AMP shared a similar pharmacological profile with the octopamine-induced increase in cyclic AMP. Tyramine increased the amplitude of excitatory junction potentials at low concentrations while hyperpolarizing the membrane potential by 2-5 mV. A further increase in the amplitude of the excitatory junction potentials and the occurrence of an active response was seen upon washing tyramine from the preparation. These results suggest that tyramine can activate at least three different endogenous receptors on the locust oviducts a putative tyramine receptor at low concentrations, a different tyramine receptor to inhibit muscle contraction, and an octopamine receptor at high concentrations.

Differential effects of sporulation temperature on the high pressure resistance of Clostridium botulinum type E spores and the interconnection with sporulation medium cation contents.

PubMed

Lenz, Christian A; Vogel, Rudi F

2015-04-01

High pressure thermal (HPT) processing can be used to improve traditional preservation methods and increase food safety and durability, whereas quality related characteristics can be largely maintained. Clostridium (C.) botulinum type E is a non-proteolytic, psychrotrophic, toxin-producing spore former, commonly associated with aquatic environments in temperate regions of the northern hemisphere. Sporulation in nature is likely to occur under varying conditions including temperature and nutrient availability, which might affect resistance properties of resulting spores. In our study, we determined the effect of sporulation temperature (13-38 °C) on the resistance of three Clostridium botulinum type E strains to differently intense HPT treatments (200 MPa at 40 and 80 °C, and 800 MPa at 40 and 80 °C). Furthermore, the effect of cations on sporulation temperature-mediated alterations in HHP resistance was investigated. Results indicate that low and high sporulation temperatures can increase and decrease sporal HPT resistance, respectively, in a treatment-dependent (pressure level, treatment temperature) manner, whereas the trends observed are largely unaffected by pressure dwells (1 s-10 min). Furthermore, results show that the cation content of the sporulation medium (Ca(2+), Mg(2+), Mn(2+)) marginally influences and partially counteracts effects on the HPT resistance of spores grown at low and elevated temperatures, respectively. This suggests that sporulation temperature and medium cations provoke changes in some common spore resistance structures. Sporulation conditions can markedly affect spore resistance properties and, thus, should be considered for the experimental setup of worst case studies aiming to evaluate the effectiveness of food processes in terms of the inactivation of C. botulinum type E spores. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of Loading Frequency on Fatigue Behavior, Residual Stress, and Microstructure of Deep-Rolled Stainless Steel AISI 304 at Elevated Temperatures

NASA Astrophysics Data System (ADS)

Nikitin, I.; Juijerm, P.

2018-02-01

The effects of loading frequency on the fatigue behavior of non-deep-rolled (NDR) and deep-rolled (DR) austenitic stainless steel AISI 304 were systematically clarified at elevated temperatures, especially at temperatures exhibiting the dynamic strain aging (DSA) phenomena. Tension-compression fatigue tests were performed isothermally at temperatures of 573 K and 773 K (300 °C and 500 °C) with different loading frequencies of 5, 0.5, 0.05, and 0.005 Hz. For the DR condition, the residual stresses and work-hardening states will be presented. It was found that DSA would be detected at appropriate temperatures and deformation rates. The cyclic deformation curves and the fatigue lives of the investigated austenitic stainless steel AISI 304 are considerably affected by the DSA, especially on the DR condition having high dislocation densities at the surface and in near-surface regions. In the temperature range of the DSA, residual stresses and work-hardening states of the DR condition seem to be stabilized. The microstructural alterations were investigated by transmission electron microscopy (TEM). At an appropriate temperature with low loading frequency, the plastic deformation mechanism shifted from a wavy slip manner to a planar slip manner in the DSA regimes, whereas the dislocation movements were obstructed.

Effect of ammonium metavanadate on the murine immune response

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

Cohen, M.D.; Wei, C.I.; Tan, H.

1986-01-01

Female B/sub 6/C/sub 3/F/sub 1/ mice were exposed to ammonium metavanadate (NH/sub 4/VO/sub 3/) by intraperitoneal injection every 3 d at 2.5, 5.0, or 10 mg V/kg for 3, 6, or 9 w and were then assayed for alterations in immunoresponsiveness. Resistance to Escherichia coli endotoxin lethality increased in a dose-dependent manner up to 6 w of exposure, while resistance to viable gram-positive Listeria lethality was depressed in a dose-dependent manner. Comparison of LD20 values indicated a 250-fold decrease in resistance to Listeria at the lowest vanadium exposure and a 40% increase in resistance to endotoxin after the highest vanadiummore » exposure. Peritoneal macrophage phagocytic capacities were decreased in a dose-dependent manner, but viabilities remained unaffected. Rosetting capacity of splenic lymphocytes was increased following vanadium exposure. Liver and splenic enlargement was observed, and examination of splenic tissue indicated enhanced formation of megakaryocytes and red blood cell precursors. Subchronic exposure to vanadium may thus disrupt the normal function of the immune system.« less

Experimental Characterization and Material Modelling of an AZ31 Magnesium Sheet Alloy at Elevated Temperatures under Consideration of the Tension-Compression Asymmetry

NASA Astrophysics Data System (ADS)

Behrens, B.-A.; Bouguecha, A.; Bonk, C.; Dykiert, M.

2017-09-01

Magnesium sheet alloys have a great potential as a construction material in the aerospace and automotive industry. However, the current state of research regarding temperature dependent material parameters for the description of the plastic behaviour of magnesium sheet alloys is scarce in literature and accurate statements concerning yield criteria and appropriate characterization tests to describe the plastic behaviour of a magnesium sheet alloy at elevated temperatures in deep drawing processes are to define. Hence, in this paper the plastic behaviour of the well-established magnesium sheet alloy AZ31 has been characterized by means of convenient mechanical tests (e. g. tension, compression and biaxial tests) at temperatures between 180 and 230 °C. In this manner, anisotropic and hardening behaviour as well as differences between the tension-compression asymmetry of the yield locus have been estimated. Furthermore, using the evaluated data from the above mentioned tests, two different yield criteria have been parametrized; the commonly used Hill’48 and an orthotropic yield criterion, CPB2006, which was developed especially for materials with hexagonal close packed lattice structure and is able to describe an asymmetrical yielding behaviour regarding tensile and compressive stress states. Numerical simulations have been finally carried out with both yield functions in order to assess the accuracy of the material models.

Antibodies enhance CXCL10 production during RSV infection of infant and adult immune cells.

PubMed

Vissers, Marloes; Schreurs, Inge; Jans, Jop; Heldens, Jacco; de Groot, Ronald; de Jonge, Marien I; Ferwerda, Gerben

2015-12-01

Respiratory syncytial virus (RSV) bronchiolitis is a major burden in infants below three months of age, when the primary immune response is mainly dependent on innate immunity and maternal antibodies. We investigated the influence of antibodies on innate immunity during RSV infection. PBMCs from infants and adults were stimulated with live RSV and inactivated RSV in combination with antibody-containing and antibody-depleted serum. The immune response was determined by transcriptome analysis and chemokine levels were measured using ELISA and flow cytometry. Microarray data showed that CXCL10 gene transcription was RSV dependent, whereas CXCL11 and IFNα were upregulated in an antibody-dependent manner. Although the presence of antibodies reduces RSV infection rate, it enhances the innate immune response. In adult immune cells, antibodies enhance CXCL10, CXCL11, IFNα and IFNγ production in response to RSV infection. Contrary, in infant immune cells only CXCL10 was enhanced in an antibody-dependent manner. Monocytes are the main source of CXCL10 and they produce CXCL10 in both an antibody- and virus-dependent manner. This study shows that antibodies enhance CXCL10 production in infant immune cells. CXCL10 has been implicated in exuberating the inflammatory response during viral infections and antibodies could therefore play a role in the pathogenesis of RSV infections. Copyright © 2015 Elsevier Ltd. All rights reserved.

Europa Lander Material Selection Considerations

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

Tappan, Alexander S.; Heller, Mellisa

2017-01-10

Energetic materials (EMs, explosives, pyrotechnics, propellants) provide high-power output of high temperature reaction products. These products can be solid, liquid, or gaseous during reaction or after the products have equilibrated with the surroundings. For example, high explosives typically consist of carbon, hydrogen, nitrogen, and oxygen bonded within a single molecule, and produce almost exclusively gaseous products. Conversely, intermetallics consist of physical mixtures of metals and metalloids, and produce almost exclusively condensed products. Other materials such as pyrotechnics and propellants have intermediate behavior. All energetic materials react in a self-propagating manner that after ignition, does not necessarily require energy input frommore » the surroundings. The range of reaction velocities can range from mm/s for intermetallics, to km/s for high explosives. Energetic material selection depends on numerous requirements specific to the needs of a system. High explosives are used for applications where high pressure gases are necessary for pushing or fracturing materials (e.g., rock, metal) or creating shock waves or air blast. Propellants are used to produce moderate-pressure, high-temperature products without a shock wave. Pyrotechnics are used to produce numerous effects including: high-temperature products, gases, light, smoke, sound, and others. Thermites are used to produce heat, high-temperature products, materials, and other effects that require condensed products. Intermetallics are used to produce high-temperature condensed products and materials, with very little gas production. Numerous categories of energetic materials exist with overlapping definitions, effects, and properties.« less

Catalysts based on PdO_ZrO2 in the hydrodechlorination reaction of chlorobenzene

NASA Astrophysics Data System (ADS)

Otroshchenko, T. P.; Turakulova, A. O.; Lokteva, E. S.; Golubina, E. V.; Lunin, V. V.

2015-07-01

The possibility of using mixed oxides of palladium and zirconium obtained with biotemplates (cellulose and wood pulp) as the precursor of catalysts for the hydrodechlorination of chlorobenzene is analyzed. The properties of the samples are studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmet-Teller (BET) method, and temperature-programmed reduction (TPR). They are then compared to the properties of a supported analogue. The biomorphic precursors are characterized by high porosity and include micropores, mesopores, and macropores; the results from TPR reveal the presence in the precursors of several forms of PdO that differ by reduction temperature. It is shown that the distribution of palladium in the catalysts obtained by reducing the precursors with hydrogen depends on the method used in synthesizing the precursor. It is shown that the studied catalysts ensure 100% conversion of chlorobenzene at temperatures of 100 to 250°C. It is established that cyclohexane is the principal product in the presence of the supported catalyst across the range of temperatures, while cyclohexane and benzene are detected among the products in the presence of biomorphous samples at temperatures above 130°C. The effect the presence of an admixture of alkaline and alkaline-earth metals in the catalyst has on the selectivity of the process is noted. It is established that the catalysts operate in a stable manner for at least 27 h of use under experimental conditions.

Flow-through PCR on a 3D qiandu-shaped polydimethylsiloxane (PDMS) microdevice employing a single heater: toward microscale multiplex PCR.

PubMed

Wu, Wenming; Loan, Kieu The Loan; Lee, Nae Yoon

2012-05-07

Consistent temperature control in an on-chip flow-through polymerase chain reaction (PCR) employing two or more heaters is one of the main obstacles for device miniaturization and integration when realizing micro total analysis systems (μTAS), and also leads to operational complexity. In this study, we propose a qiandu (right triangular prism)-shaped polydimethylsiloxane (PDMS) microdevice with serpentine microchannels fabricated on its slanted plane, and apply the device for an on-chip flow-through PCR employing a single heater. The inclined nature of the qiandu-shaped microdevice enables the formation of a surface temperature gradient along the slanted plane of the microdevice in a height-dependent manner by the use of a single heater, and enables liquid to traverse over wide ranges of temperatures, including the three temperature zones--denaturation, annealing, and extension temperatures--required in a typical PCR. The feasibility of the qiandu-shaped PDMS microdevice as a versatile platform for performing a flow-through PCR was examined by employing multiple templates and varying the inclination angle of the device. In addition, the potential of performing a multiplex PCR using a single qiandu-shaped PDMS microdevice was explored. A 409 bp long gene fragment effective as a marker for diagnosing lung cancer and a 230 bp long gene fragment from a plasmid vector were simultaneously amplified in less than 25 min on a single microdevice, paving the way for a microscale, multiplex PCR on a single device employing a single heater.

Dielectric maximum temperature non-monotonic behavior in unaxial Sr0.75Ba0.25Nb2O6 relaxor seen via acoustic emission

NASA Astrophysics Data System (ADS)

Dul'kin, E.; Kojima, S.; Roth, M.

2011-08-01

[100] oriented Sr0.75Ba0.25Nb2O6 relaxor crystals have been studied by means of acoustic emission (AE) over a wide 20-400 °C temperature range. Both the Burns temperature, Td = 350 °C, and the intermediate temperature, T* = 183°C, and the susceptibility maximum temperature, Tm (59 °C on heating and 47 °C on cooling), have been successfully detected. Dependent upon the external electric field, the Tm exhibits a local minimum near 0.25 kV/cm accompanied by pronounced AE maximum in a manner which had recently been detected in Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 by Dul'kin et al. [Appl. Phys. Lett. 94, 252904 (2009)] and in Pb(Sc1/2Ta1/2)O3 by Dul'kin et al. [Phys. Rev. B 82, 180101(R) (2010)], whereas the T* increases monotonically, similar to that which had recently been revealed in BaTiO3 by Dul'kin et al. [Appl. Phys. Lett. 97, 032903 (2010)] with a rate of 7.5 K cm/kV. An observed Tm behavior is discussed from the point of view of the existence of the random electric field components along the [100] direction in Sr0.75Ba0.25Nb2O6 crystals.

Archaeal Genome Organization and Stress Responses: Implications for the Origin and Evolution of Cellular Life

NASA Astrophysics Data System (ADS)

Musgrave, David; Zhang, Xiaoying; Dinger, Marcel

2002-08-01

For DNA to be used as an informational molecule it must exist in the cell on the edge of stability because all genomic processes require local controlled melting. This presents mechanistic opportunities and problems for genomic DNA from hyperthermophilic organisms, whose unpackaged DNA could melt at optimal temperatures for growth. Hyperthermophiles are suggested to employ the novel positively supercoiling topoisomerase enzyme reverse gyrase (RG) to form positively supercoiled DNA that is intrinsically resistant to thermal denaturation. RG is presently the only archaeal gene that is uniquely found in hyperthermophiles and therefore is central to hypotheses suggesting a hypothermophilic origin of life. However, the suggestion that RG has evolved by the fusion of two pre-existing enzymes has led to hypotheses for a lower temperature for the origin of life. In addition to the action of topoisomerases, DNA packaging and the intracellular ionic environment can also manipulate DNA topology significantly. In the Euryarchaeota, nucleosomes containing minimal histones can adopt two alternate DNA topologies in a salt-dependent manner. From this we hypothesize that since internal salt concentrations are increased following an increase in temperature, the genomic effects of temperature fluctuations could also be accommodated by changes in nucleosome organization. In addition, stress-induced changes in the nucleoid proteins could also play a role in maintaining the genome in the optimal topological state in changing environments. The function of these systems could therefore be central to temperature adaptation and thus be implicated in origin of life scenarios involving hyperthermophiles.

Microscopic heat pulses induce contraction of cardiomyocytes without calcium transients

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

Oyama, Kotaro; Mizuno, Akari; Shintani, Seine A.

Highlights: Black-Right-Pointing-Pointer Infra-red laser beam generates microscopic heat pulses. Black-Right-Pointing-Pointer Heat pulses induce contraction of cardiomyocytes. Black-Right-Pointing-Pointer Ca{sup 2+} transients during the contraction were not detected. Black-Right-Pointing-Pointer Skinned cardiomyocytes in free Ca{sup 2+} solution also contracted. Black-Right-Pointing-Pointer Heat pulses regulated the contractions without Ca{sup 2+} dynamics. -- Abstract: It was recently demonstrated that laser irradiation can control the beating of cardiomyocytes and hearts, however, the precise mechanism remains to be clarified. Among the effects induced by laser irradiation on biological tissues, temperature change is one possible effect which can alter physiological functions. Therefore, we investigated the mechanism by which heatmore » pulses, produced by infra-red laser light under an optical microscope, induce contractions of cardiomyocytes. Here we show that microscopic heat pulses induce contraction of rat adult cardiomyocytes. The temperature increase, {Delta}T, required for inducing contraction of cardiomyocytes was dependent upon the ambient temperature; that is, {Delta}T at physiological temperature was lower than that at room temperature. Ca{sup 2+} transients, which are usually coupled to contraction, were not detected. We confirmed that the contractions of skinned cardiomyocytes were induced by the heat pulses even in free Ca{sup 2+} solution. This heat pulse-induced Ca{sup 2+}-decoupled contraction technique has the potential to stimulate heart and skeletal muscles in a manner different from the conventional electrical stimulations.« less

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.

[Cellular uptake of TPS-L-carnitine synthesised as transporter-based renal targeting prodrug].

PubMed

Li, Li; Zhu, Di; Sun, Xun

2012-11-01

To synthesize transporter-based renal targeting prodrug TPS-L-Carnitine and to determine its cellular uptake in vitro. Triptolide (TP) was conjugated with L-carnitine using succinate as the linker to form TPS-L-Carnitine, which could be specifically recognized by OCTN2, a cationic transporter with high affinity to L-Carnitine and is highly expressed on the apical membrane of renal proximal tubule cells. Cellular uptake assays of the prodrug and its parent drug were performed on HK-2 cells, a human proximal tubule cell line, in different temperature, concentration and in the presence of competitive inhibitors. TPS-L-Carnitine was taken up into HK-2 cells in a saturable and temperature- and concentration-dependent manner. The uptake process could be inhibited by the competitive inhibitors. The uptake of TPS-L-Carnitine was significantly higher than that of TP at 37 degrees C in the same drug concentration. TPS-L-Carnitine was taken through endocytosis mediated by transporter. TPS-L-Carnitine provides a good renal targeting property and lays the foundation for further studies in vivo.

Hydrolysis of Glycosidic Flavonoids during the Preparation of Danggui Buxue Tang: An Outcome of Moderate Boiling of Chinese Herbal Mixture

PubMed Central

Zhang, Wendy Li; Chen, Jian-Ping; Lam, Kelly Yin-Ching; Zhan, Janis Ya-Xian; Yao, Ping; Dong, Tina Ting-Xia; Tsim, Karl Wah-Keung

2014-01-01

Chemical change during boiling of herbal mixture is a puzzle. By using Danggui Buxue Tang (DBT), a herbal decoction that contains Astragali Radix (AR) and Angelicae Sinensis Radix (ASR), we developed a model in analyzing the hydrolysis of flavonoid glycosides during the boiling of herbal mixture in water. A proper preparation of DBT is of great benefit to the complete extraction of bioactive ingredients. Boiling of DBT in water increased the solubility of AR-derived astragaloside IV, calycosin, formononetin, calycosin-7-O-β-D-glucoside, and ononin in a time- and temperature-dependent manner: the amounts of these chemicals reached a peak at 2 h. The glycosidic resides of AR, calycosin-7-O-β-D-glucoside, and ononin could be hydrolyzed during the moderate boiling process to form calycosin and formononetin, respectively. The hydrolysis efficiency was strongly affected by pH, temperature, and amount of herbs. Interestingly, the preheated herbs were not able to show this hydrolytic activity. The current results supported the rationality of ancient preparation of DBT in boiling water by moderate heat. PMID:24744813

Pressure Induced Phase Transformations of Silica Polymorphs and Glasses

NASA Astrophysics Data System (ADS)

Cagin, Tahir; Demiralp, Ersan; Goddard, William A., III

1998-03-01

Silica, SiO_2, is one of the most widely studied substance, and it has some complex and unusual properties. We have used a recently developed 2-body interaction force field (E. Demiralp, T. Cagin, W.A. Goddard, III, unpublished.) to study the structural phase transformations in silica under various pressure loading conditions. The specific transformations we studied are α-quartz to stishovite, coesite to stishovite and fused glass to stishovite-like dense, a dominantly six-coordinated glassy phase. Molecular dynamics simulations are performed under the constant loading rates ranging from 0.1 GPa/ps to 2.0 GPa/ps, pressures upto 100 GPa and at temperatures 300, 500, 700 and 900 K. We observe the crystal to crystal transformations to occur reconstructively, whereas it occurs in a smooth and displacive manner from glass to a stishovite-like phase confirming earlier conjectures. (E.M. Stolper and T.J. Ahrens, Geophys. Res. Let.) 14, 1231 (1987). To elucidate the shock loading experiments, we studied the dependence of transition pressure on the loading rate and the temperature. To assess the hysterisis effect we also studied the unloading behavior of each transformation.

Trypsin from the pyloric caeca of bluefish (Pomatomus saltatrix).

PubMed

Klomklao, Sappasith; Benjakul, Soottawat; Visessanguan, Wonnop; Kishimura, Hideki; Simpson, Benjamin K

2007-12-01

Trypsin was purified from the pyloric caeca of bluefish (Pomatomus saltatrix) by ammonium sulfate precipitation, acetone precipitation and soybean trypsin inhibitor-Sepharose 4B affinity chromatography. Bluefish trypsin migrated as a single band using both sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and native-PAGE and had a molecular mass of 28 kDa. The optima pH and temperature for the hydrolysis of benzoyl-dl-arginine-p-nitroanilide (BAPNA) were 9.5 and 55 degrees C, respectively. The enzyme was stable over a broad pH range (7 to 12), but was unstable at acidic pH, and at temperatures greater than 40 degrees C. The enzyme was inhibited by specific trypsin inhibitors: soybean trypsin inhibitor (SBTI), N-p-tosyl-l-lysine chloromethyl ketone (TLCK) and the serine protease inhibitor phenylmethyl sulfonylfluoride (PMSF). CaCl2 partially protected trypsin against activity loss at 40 degrees C, but NaCl (0 to 30%) decreased the activity in a concentration dependent manner. The N-terminal amino acid sequence of trypsin was determined as IVGGYECKPKSAPVQVSLNL and was highly homologous to other known vertebrate trypsins.

Plasma rate coefficients for electron-impact ionization of Xeq+ ions (q = 8, …, 17)

NASA Astrophysics Data System (ADS)

Borovik, A., Jr.; Gharaibeh, M. F.; Schippers, S.; Müller, A.

2015-02-01

Plasma rate coefficients (PRCs) for electron-impact single ionization of ground-state Xeq+ ions (q=8,\\ldots ,17) in the temperature range 2 × 105 - 2 × 107 K have been derived from a combination of experimental cross-section data and results of distorted-wave calculations. For Xe8+ and Xe9+ new measurements were performed and thoroughly analyzed with respect to the contributions from different ionization mechanisms and the effects of long-lived excited states in the parent ion beams that had been employed in the experiments. In the same manner, previously published experimental data for the higher charge states were analyzed to extract the ground-configuration ionization cross sections and to derive the associated PRCs. The resulting temperature-dependent PRC functions were parameterized and the associated parameters are provided in tabular form. With the exception of Xe8+ the absolute uncertainties of the inferred rate coefficients are estimated to be +/- 10%. For Xe8+ the uncertainties are +/- 25% due to the necessary correction for strong metastable-ion contributions to the measured cross sections.

Comparative evaluation of maceration and ultrasonic-assisted extraction of phenolic compounds from fresh olives.

PubMed

Deng, Junlin; Xu, Zhou; Xiang, Chunrong; Liu, Jing; Zhou, Lijun; Li, Tian; Yang, Zeshen; Ding, Chunbang

2017-07-01

Ultrasonic-assisted extraction (UAE) and maceration extraction (ME) were optimized using response surface methodology (RSM) for total phenolic compounds (TPC) from fresh olives. The main phenolic compounds and antioxidant activity of TPC were also investigated. The optimized result for UAE was 22mL/g of liquid-solid ratio, 47°C of extraction temperature and 30min of extraction time, 7.01mg/g of yielding, and for ME was 24mL/g of liquid-solid ratio, 50°C of extraction temperature and 4.7h of extraction time, 5.18mg/g of yielding. The HPLC analysis revealed that the extracts by UAE and ME possessed 14 main phenolic compounds, and UAE exhibited more amounts of all phenols than ME. The most abundant phenolic compounds in olive extracts were hydroxytyrosol, oleuropein and rutin. Both extracts showed excellent antioxidant activity in a dose-dependent manner. Taken together, UAE could effectively increase the yield of phenolic compounds from olives. In addition these phenolic compounds could be used as a potential source of natural antioxidants. Copyright © 2017 Elsevier B.V. All rights reserved.

[Are simple time lags responsible for cyclic variation of population density? : A comparison of laboratory population dynamics of Brachionus calyciflorus pallas (rotatoria) with computer simulations].

PubMed

Halbach, Udo; Burkhardt, Heinz Jürgen

1972-09-01

Laboratory populations of the rotifer Brachionus calyciflorus were cultured at different temperatures (25, 20, 15°C) but otherwise at constant conditions. The population densities showed relatively constant oscillations (Figs. 1 to 3A-C). Amplitudes and frequencies of the oscillations were positively correlated with temperature (Table 1). A test was made, whether the logistic growth function with simple time lag is able to describe the population curves. There are strong similarities between the simulations (Figs. 1-3E) and the real population dynamics if minor adjustments of the empirically determined parameters are made. There-fore it is suggested that time lags are responsible for the observed oscillations. However, the actual time lags probably do not act in the simple manner of the model, because birth and death rates react with different time lags, and both parameters are dependent on individual age and population density. A more complex model, which incorporates these modifications, should lead to a more realistic description of the observed oscillations.

HtrA Is Important for Stress Resistance and Virulence in Haemophilus parasuis

PubMed Central

Zhang, Luhua; Li, Ying; Wen, Yiping; Lau, Gee W.; Huang, Xiaobo; Wu, Rui; Yan, Qigui; Huang, Yong; Zhao, Qin; Ma, Xiaoping

2016-01-01

Haemophilus parasuis is an opportunistic pathogen that causes Glässer's disease in swine, with polyserositis, meningitis, and arthritis. The high-temperature requirement A (HtrA)-like protease, which is involved in protein quality control, has been reported to be a virulence factor in many pathogens. In this study, we showed that HtrA of H. parasuis (HpHtrA) exhibited both chaperone and protease activities. Finally, nickel import ATP-binding protein (NikE), periplasmic dipeptide transport protein (DppA), and outer membrane protein A (OmpA) were identified as proteolytic substrates for HpHtrA. The protease activity reached its maximum at 40°C in a time-dependent manner. Disruption of the htrA gene from strain SC1401 affected tolerance to temperature stress and resistance to complement-mediated killing. Furthermore, increased autoagglutination and biofilm formation were detected in the htrA mutant. In addition, the htrA mutant was significantly attenuated in virulence in the murine model of infection. Together, these data demonstrate that HpHtrA plays an important role in the virulence of H. parasuis. PMID:27217419

HtrA Is Important for Stress Resistance and Virulence in Haemophilus parasuis.

PubMed

Zhang, Luhua; Li, Ying; Wen, Yiping; Lau, Gee W; Huang, Xiaobo; Wu, Rui; Yan, Qigui; Huang, Yong; Zhao, Qin; Ma, Xiaoping; Wen, Xintian; Cao, Sanjie

2016-08-01

Haemophilus parasuis is an opportunistic pathogen that causes Glässer's disease in swine, with polyserositis, meningitis, and arthritis. The high-temperature requirement A (HtrA)-like protease, which is involved in protein quality control, has been reported to be a virulence factor in many pathogens. In this study, we showed that HtrA of H. parasuis (HpHtrA) exhibited both chaperone and protease activities. Finally, nickel import ATP-binding protein (NikE), periplasmic dipeptide transport protein (DppA), and outer membrane protein A (OmpA) were identified as proteolytic substrates for HpHtrA. The protease activity reached its maximum at 40°C in a time-dependent manner. Disruption of the htrA gene from strain SC1401 affected tolerance to temperature stress and resistance to complement-mediated killing. Furthermore, increased autoagglutination and biofilm formation were detected in the htrA mutant. In addition, the htrA mutant was significantly attenuated in virulence in the murine model of infection. Together, these data demonstrate that HpHtrA plays an important role in the virulence of H. parasuis. Copyright © 2016 Zhang et al.

Inhibition of gamma-radiation induced DNA damage in plasmid pBR322 by TMG, a water-soluble derivative of vitamin E.

PubMed

Rajagopalan, Rema; Wani, Khalida; Huilgol, Nagaraj G; Kagiya, Tsutomu V; Nair, Cherupally K Krishnan

2002-06-01

Alpha-tocopherol monoglucoside (TMG), a water-soluble derivative of alpha-tocopherol, has been examined for its ability to protect DNA against radiation-induced strand breaks. Gamma radiation, up to a dose of 6 Gy (dose rate, 0.7 Gy/minute), induced a dose-dependent increase in single strand breaks (SSBs) in plasmid pBR322 DNA. TMG inhibited the formation of gamma-radiation induced DNA single strand breaks (SSBs) in a concentration-dependent manner; 500 microM of TMG protected the single strand breaks completely. It also protected thymine glycol formation induced by gamma-radiation in a dose-dependent manner, based on an estimation of thymine glycol by HPLC.

OBSERVATIONS OF SIMILARITY THEORY STABILITY CORRECTION TERMS FOR MOMENTUM AND TEMPERATURE, OVER AGRICULTURAL FIELDS AND FORESTS.

EPA Science Inventory

Many observations of temperature and wind speed profiles have been taken over "ideal" terrain and analyzed to develop the stability correction terms which are commonly used in the application of similarity theory. Fewer observations have been taken and analyzed in this manner ov...

Transport properties of silicon complementary-metal-oxide semiconductor quantum well field-effect transistors

NASA Astrophysics Data System (ADS)

Naquin, Clint Alan

Introducing explicit quantum transport into silicon (Si) transistors in a manner compatible with industrial fabrication has proven challenging, yet has the potential to transform the performance horizons of large scale integrated Si devices and circuits. Explicit quantum transport as evidenced by negative differential transconductances (NDTCs) has been observed in a set of quantum well (QW) n-channel metal-oxide-semiconductor (NMOS) transistors fabricated using industrial silicon complementary MOS processing. The QW potential was formed via lateral ion implantation doping on a commercial 45 nm technology node process line, and measurements of the transfer characteristics show NDTCs up to room temperature. Detailed gate length and temperature dependence characteristics of the NDTCs in these devices have been measured. Gate length dependence of NDTCs shows a correlation of the interface channel length with the number of NDTCs formed as well as with the gate voltage (VG) spacing between NDTCs. The VG spacing between multiple NDTCs suggests a quasi-parabolic QW potential profile. The temperature dependence is consistent with partial freeze-out of carrier concentration against a degenerately doped background. A folding amplifier frequency multiplier circuit using a single QW NMOS transistor to generate a folded current-voltage transfer function via a NDTC was demonstrated. Time domain data shows frequency doubling in the kHz range at room temperature, and Fourier analysis confirms that the output is dominated by the second harmonic of the input. De-embedding the circuit response characteristics from parasitic cable and contact impedances suggests that in the absence of parasitics the doubling bandwidth could be as high as 10 GHz in a monolithic integrated circuit, limited by the transresistance magnitude of the QW NMOS. This is the first example of a QW device fabricated by mainstream Si CMOS technology being used in a circuit application and establishes the feasibility of scalable CMOS circuits that exploit explicit quantum transport. Ongoing quantum transport simulations based off of the spatial dopant distribution suggests a quasi-parabolic potential profile. Energy spacings between resonant transmission states are not consistent with experimental data, suggesting that either the assumed transport model is incomplete, or scattering mechanisms significantly mix the quasi-bound states and broaden the energy spacings.

Circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, feeding and activity in rats.

PubMed

Kamerman, Peter; Mitchell, Duncan; Laburn, Helen

2002-02-01

We have investigated whether there is circadian variation in the effects of nitric oxide synthase inhibitors on body temperature, physical activity and feeding. We used nocturnally active Sprague-Dawley rats, housed at approximately 24 degrees C with a 12:12 h light:dark cycle (lights on 07:00 hours) and provided with food and water ad libitum. Nitric oxide synthesis was inhibited by intraperitoneal injection of the unspecific nitric oxide synthase inhibitor N-nitro- L-arginine methyl ester ( L-NAME, 100, 50, 25, 10 mg/kg), or the relatively selective inducible nitric oxide synthase inhibitor aminoguanidine (100, 50 mg/kg), during the day ( approximately 09:00 hours) or night ( approximately 21:00 hours). Body temperature and physical activity were measured using radiotelemetry, while food intake was calculated by weighing each animal's food before as well as 12 and 24 h after each injection. We found that daytime injection of L-NAME and aminoguanidine had no effect on daytime body temperature. However, daytime injection of both drugs did decrease nocturnal food intake ( P<0.05) and activity ( P<0.05). When injected at night, L-NAME reduced night-time body temperature ( P<0.01), activity ( P<0.05) and food intake ( P<0.05) in a dose-dependent manner, but night-time injection of aminoguanidine inhibited only night-time activity ( P<0.05). The effects of nitric oxide synthase inhibition on body temperature, feeding and activity therefore are primarily a consequence of inhibiting constitutively expressed nitric oxide synthase, and are subject to circadian variation.

Arginine vasopressin antagonizes the effects of prostaglandin E2 on the spontaneous activity of warm-sensitive and temperature-insensitive neurons in the medial preoptic area in rats.

PubMed

Xu, Jian-Hui; Hou, Xiao-Yu; Tang, Yu; Luo, Rong; Zhang, Jie; Liu, Chang; Yang, Yong-Lu

2018-01-01

Arginine vasopressin (AVP) plays an important role in thermoregulation and antipyresis. We have demonstrated that AVP could change the spontaneous activity of thermosensitive and temperature insensitive neurons in the preoptic area. However, whether AVP influences the effects of prostaglandin E 2 (PGE 2 ) on the spontaneous activity of neurons in the medial preoptic area (MPO) remains unclear. Our experiment showed that PGE 2 decreased the spontaneous activity of warm-sensitive neurons, and increased that of low-slope temperature-insensitive neurons in the MPO. AVP attenuated the inhibitory effect of PGE 2 on warm-sensitive neurons, and reversed the excitatory effect of PGE 2 on low-slope temperature-insensitive neurons, demonstrating that AVP antagonized the effects of PGE 2 on the spontaneous activity of these neurons. The effect of AVP was suppressed by an AVP V 1a receptor antagonist, suggesting that V 1a receptor mediated the action of AVP. We also demonstrated that AVP attenuated the PGE 2 -induced decrease in the prepotential's rate of rise in warm-sensitive neurons and the PGE 2 -induced increase in that in low-slope temperature-insensitive neurons through the V 1a receptor. Together, these data indicated that AVP antagonized the PGE 2 -induced change in the spontaneous activity of warm-sensitive and low-slope temperature-insensitive neurons in the MPO partly by reducing the PGE 2 -induced change in the prepotential of these neurons in a V 1a receptor-dependent manner. Copyright © 2017 Elsevier B.V. All rights reserved.

Persistent effects of incubation temperature on muscle development in larval haddock (Melanogrammus aeglefinus L.).

PubMed

Martell, D John; Kieffer, James D

2007-04-01

Muscle development and growth were investigated in haddock larvae (Melanogrammus aeglefinus L.) incubated under controlled temperatures (4, 6, 8 degrees C) and reared post-hatch through yolk-dependent and exogenous-feeding stages in a 6 degrees C post-hatch environment. Changes in cell number and size in superficial and deep myotomes within the epaxial muscle were investigated for 28 days following hatch. Distinct and significant differences in muscle cellularity following separate developmental strategies were observed in superficial and deep myotomes. The number of superficial myofibres increased with time and, although not in a manner proportional to temperature during the first 21 days post hatch (d.p.h.), there was observed a trend during the final 7 days of greater mean cell size that was strongly associated with increased temperature. In addition, there was an apparent correspondence between increased temperature and increased size between 21 and 28 d.p.h. Among all temperature groups the superficial myotome not only demonstrated a consistent unimodal myofibre-size distribution but one that increased in range proportional to temperature. In the deep muscle, myotomes from higher incubation temperatures had a broader range of fibre sizes and greater numbers of myofibres. The onset of a proliferative event, characterized by a significant recruitment of new smaller myofibres and a bimodal distribution of cell sizes, was directly proportional to incubation temperature such that it occurred at 14 d.p.h. at 8 degrees C but not until 28 d.p.h. at 4 degrees C. The magnitude of that recruitment was also directly proportional to temperature. Following hatch, those embryos from the greatest temperature groups had the largest mean deep muscle size but, as a result of the proliferative event, had the smallest-sized cells 28 days later. The muscle developmental and growth strategy as indicated by sequential changes in cellularity and cell-size distributions between myotomes in response to temperature are also discussed in light of whole animal growth and development.

Temperature and population density: interactional effects of environmental factors on phenotypic plasticity, immune defenses, and disease resistance in an insect pest.

PubMed

Silva, Farley W S; Elliot, Simon L

2016-06-01

Temperature and crowding are key environmental factors mediating the transmission and epizooty of infectious disease in ectotherm animals. The host physiology may be altered in a temperature-dependent manner and thus affects the pathogen development and course of diseases within an individual and host population, or the transmission rates (or infectivity) of pathogens shift linearly with the host population density. To our understanding, the knowledge of interactive and synergistic effects of temperature and population density on the host-pathogen system is limited. Here, we tested the interactional effects of these environmental factors on phenotypic plasticity, immune defenses, and disease resistance in the velvetbean caterpillar Anticarsia gemmatalis . Upon egg hatching, caterpillars were reared in thermostat-controlled chambers in a 2 × 4 factorial design: density (1 or 8 caterpillars/pot) and temperature (20, 24, 28, or 32°C). Of the immune defenses assessed, encapsulation response was directly affected by none of the environmental factors; capsule melanization increased with temperature in both lone- and group-reared caterpillars, although the lone-reared ones presented the most evident response, and hemocyte numbers decreased with temperature regardless of the population density. Temperature, but not population density, affected considerably the time from inoculation to death of velvetbean caterpillar. Thus, velvetbean caterpillars succumbed to Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) more quickly at higher temperatures than at lower temperatures. As hypothesized, temperature likely affected caterpillars' movement rates, and thus the contact between conspecifics, which in turn affected the phenotypic expression of group-reared caterpillars. Our results suggest that environmental factors, mainly temperature, strongly affect both the course of disease in velvetbean caterpillar population and its defenses against pathogens. As a soybean pest, velvetbean caterpillar may increase its damage on soybean fields under a scenario of global warming as caterpillars may reach the developmental resistance faster, and thus decrease their susceptibility to biological control by AgMNPV.

Temperature measurement method using temperature coefficient timing for resistive or capacitive sensors

DOEpatents

Britton, C.L. Jr.; Ericson, M.N.

1999-01-19

A method and apparatus for temperature measurement especially suited for low cost, low power, moderate accuracy implementation. It uses a sensor whose resistance varies in a known manner, either linearly or nonlinearly, with temperature, and produces a digital output which is proportional to the temperature of the sensor. The method is based on performing a zero-crossing time measurement of a step input signal that is double differentiated using two differentiators functioning as respective first and second time constants; one temperature stable, and the other varying with the sensor temperature. 5 figs.

Actin cytoskeleton as a putative target of the neem limonoid Azadirachtin A.

PubMed

Anuradha, Aritakula; Annadurai, Ramaswamy S; Shashidhara, L S

2007-06-01

Limonoids isolated from the Indian neem tree (Azadirachta indica) have been gaining global acceptance in agricultural applications and in contemporary medicine for their myriad but discrete properties. However, their mode of action is still not very well understood. We have studied the mode of action of Azadirachtin A, the major limonoid of neem seed extracts, using Drosophila melanogaster as the model system. Azadirachtin A induces moderate-to-severe phenotypes in different tissues in a dose-dependent manner. At the cellular level, Azadirachtin A induces depolymerization of Actin leading to arrest of cells and subsequently apoptosis in a caspase-independent manner. Azadirachtin A-induced phenotypes were rescued by the over-expression of Cyclin E in a tissue-dependent manner. Cyclin E, which caused global rescue of Azadirachtin A-induced phenotypes, also effected rearrangement of the actin filaments. These results suggest that probably actin is a target of Azadirachtin A activity.

Olivine anisotropy suggests Gutenberg discontinuity is not the base of the lithosphere

PubMed Central

Qi, Chao; Warren, Jessica M.

2016-01-01

Tectonic plates are a key feature of Earth’s structure, and their behavior and dynamics are fundamental drivers in a wide range of large-scale processes. The operation of plate tectonics, in general, depends intimately on the manner in which lithospheric plates couple to the convecting interior. Current debate centers on whether the transition from rigid lithosphere to flowing asthenosphere relates to increases in temperature or to changes in composition such as the presence of a small amount of melt or an increase in water content below a specified depth. Thus, the manner in which the rigid lithosphere couples to the flowing asthenosphere is currently unclear. Here we present results from laboratory-based torsion experiments on olivine aggregates with and without melt, yielding an improved database describing the crystallographic alignment of olivine grains. We combine this database with a flow model for oceanic upper mantle to predict the structure of the seismic anisotropy beneath ocean basins. Agreement between our model and seismological observations supports the view that the base of the lithosphere is thermally controlled. This model additionally supports the idea that discontinuities in velocity and anisotropy, often assumed to be the base of the lithosphere, are, instead, intralithospheric features reflecting a compositional boundary established at midocean ridges, not a rheological boundary. PMID:27606485

Olivine anisotropy suggests Gutenberg discontinuity is not the base of the lithosphere.

PubMed

Hansen, Lars N; Qi, Chao; Warren, Jessica M

2016-09-20

Tectonic plates are a key feature of Earth's structure, and their behavior and dynamics are fundamental drivers in a wide range of large-scale processes. The operation of plate tectonics, in general, depends intimately on the manner in which lithospheric plates couple to the convecting interior. Current debate centers on whether the transition from rigid lithosphere to flowing asthenosphere relates to increases in temperature or to changes in composition such as the presence of a small amount of melt or an increase in water content below a specified depth. Thus, the manner in which the rigid lithosphere couples to the flowing asthenosphere is currently unclear. Here we present results from laboratory-based torsion experiments on olivine aggregates with and without melt, yielding an improved database describing the crystallographic alignment of olivine grains. We combine this database with a flow model for oceanic upper mantle to predict the structure of the seismic anisotropy beneath ocean basins. Agreement between our model and seismological observations supports the view that the base of the lithosphere is thermally controlled. This model additionally supports the idea that discontinuities in velocity and anisotropy, often assumed to be the base of the lithosphere, are, instead, intralithospheric features reflecting a compositional boundary established at midocean ridges, not a rheological boundary.

Expression of Inapproptriate Cadherins in Human Breast Carcinomas

DTIC Science & Technology

2000-08-01

fibroblast growth factor receptor signaling. * We showed that cadherin 11 acts in a manner... fibroblast growth factor receptor signaling; and that cadherin 11 promotes epithelial cell motility in a manner similar to N-cadherin. 28 N-Cadherin...levels of E-cadherin; and that N- cadherin-dependent motility may be mediated by fibroblast growth factor receptor signaling. 14. SUBJECT TERMS

The contribution of inositol 1,4,5-trisphosphate and ryanodine receptors to agonist-induced Ca(2+) signaling of airway smooth muscle cells.

PubMed

Bai, Yan; Edelmann, Martin; Sanderson, Michael J

2009-08-01

The relative contribution of inositol 1,4,5-trisphosphate (IP(3)) receptors (IP(3)Rs) and ryanodine receptors (RyRs) to agonist-induced Ca(2+) signaling in mouse airway smooth muscle cells (SMCs) was investigated in lung slices with phase-contrast or laser scanning microscopy. At room temperature (RT), methacholine (MCh) or 5-hydroxytryptamine (5-HT) induced Ca(2+) oscillations and an associated contraction in small airway SMCs. The subsequent exposure to an IP(3)R antagonist, 2-aminoethoxydiphenyl borate (2-APB), inhibited the Ca(2+) oscillations and induced airway relaxation in a concentration-dependent manner. 2-APB also inhibited Ca(2+) waves generated by the photolytic release of IP(3). However, the RyR antagonist ryanodine had no significant effect, at any concentration, on airway contraction or agonist- or IP(3)-induced Ca(2+) oscillations or Ca(2+) wave propagation. By contrast, a second RyR antagonist, tetracaine, relaxed agonist-contracted airways and inhibited agonist-induced Ca(2+) oscillations in a concentration-dependent manner. However, tetracaine did not affect IP(3)-induced Ca(2+) release or wave propagation nor the Ca(2+) content of SMC Ca(2+) stores as evaluated by Ca(2+)-release induced by caffeine. Conversely, both ryanodine and tetracaine completely blocked agonist-independent slow Ca(2+) oscillations induced by KCl. The inhibitory effects of 2-APB and absence of an effect of ryanodine on MCh-induced airway contraction or Ca(2+) oscillations of SMCs were also observed at 37 degrees C. In Ca(2+)-permeable SMCs, tetracaine inhibited agonist-induced contraction without affecting intracellular Ca(2+) levels indicating that relaxation also resulted from a reduction in Ca(2+) sensitivity. These results indicate that agonist-induced Ca(2+) oscillations in mouse small airway SMCs are primary mediated via IP(3)Rs and that tetracaine induces relaxation by both decreasing Ca(2+) sensitivity and inhibiting agonist-induced Ca(2+) oscillations via an IP(3)-dependent mechanism.

Neurokinin B administration induces hot flushes in women.

PubMed

Jayasena, Channa N; Comninos, Alexander N; Stefanopoulou, Evgenia; Buckley, Adam; Narayanaswamy, Shakunthala; Izzi-Engbeaya, Chioma; Abbara, Ali; Ratnasabapathy, Risheka; Mogford, Julianne; Ng, Noel; Sarang, Zubair; Ghatei, Mohammad A; Bloom, Stephen R; Hunter, Myra S; Dhillo, Waljit S

2015-02-16

Neurokinin B (NKB) is a hypothalamic neuropeptide binding preferentially to the neurokinin 3 receptor. Expression of the gene encoding NKB is elevated in postmenopausal women. Furthermore, rodent studies suggest that NKB signalling may mediate menopausal hot flushes. However, the effects of NKB administration on hot flushes have not been investigated in humans. To address this, we performed a randomised, double-blinded, placebo-controlled, 2-way cross-over study. Ten healthy women were admitted to a temperature and humidity-controlled research unit. Participants received 30 minute intravenous infusions of NKB and vehicle in random order. Symptoms, heart rate, blood pressure, sweating and skin temperature were compared between NKB and vehicle in a double-blinded manner. Eight of ten participants experienced flushing during NKB infusion with none experiencing flushing during vehicle infusion (P = 0.0007). Significant elevations in heart rate (P = 0.0106 vs. pre-symptoms), and skin temperature measured using skin probe (P = 0.0258 vs. pre-symptoms) and thermal imaging (P = 0.0491 vs. pre-symptoms) characteristic of menopausal flushing were observed during hot flush episodes. Our findings provide evidence that NKB administration can cause hot flushes in women. Further studies are required to determine if pharmacological blockade of NKB signalling could inhibit hot flushes during the menopause and during treatment for sex-steroid dependent cancers.

Life-span extension by a metacaspase in the yeast Saccharomyces cerevisiae.

PubMed

Hill, Sandra Malmgren; Hao, Xinxin; Liu, Beidong; Nyström, Thomas

2014-06-20

Single-cell species harbor ancestral structural homologs of caspase proteases, although the evolutionary benefit of such apoptosis-related proteins in unicellular organisms is unclear. Here, we found that the yeast metacaspase Mca1 is recruited to the insoluble protein deposit (IPOD) and juxtanuclear quality-control compartment (JUNQ) during aging and proteostatic stress. Elevating MCA1 expression counteracted accumulation of unfolded proteins and aggregates and extended life span in a heat shock protein Hsp104 disaggregase- and proteasome-dependent manner. Consistent with a role in protein quality control, genetic interaction analysis revealed that MCA1 buffers against deficiencies in the Hsp40 chaperone YDJ1 in a caspase cysteine-dependent manner. Life-span extension and aggregate management by Mca1 was only partly dependent on its conserved catalytic cysteine, which suggests that Mca1 harbors both caspase-dependent and independent functions related to life-span control. Copyright © 2014, American Association for the Advancement of Science.

Effects of calcium on hepatocyte iron uptake from transferrin, iron-pyrophosphate and iron-ascorbate.

PubMed

Nilsen, T

1991-10-16

Calcium stimulates hepatocyte iron uptake from transferrin, ferric-iron-pyrophosphate and ferrous-iron-ascorbate. Maximal stimulation of iron uptake is observed at 1-1.5 mM of extra-cellular calcium and the effect is reversible and immediate. Neither the receptor affinity for transferrin, nor the total amounts of transferrin associated with the cells or the rate of transferrin endocytosis are significantly affected by calcium. In the presence of calcium the rate of iron uptake of non-transferrin bound iron increases abruptly at approximate 17 degrees C and 27 degrees C and as assessed by Arrhenius plots, the activation energy is reduced in a calcium dependent manner at approx. 27 degrees C. At a similar temperature, i.e., between 25 degrees C and 28 degrees C, calcium increases the rates of cellular iron uptake from transferrin in a way that is not reflected in the rate of transferrin endocytosis. By the results of this study it is concluded that calcium increases iron transport across the plasma membrane by a mechanism dependent on membrane fluidity.

ZapE Is a Novel Cell Division Protein Interacting with FtsZ and Modulating the Z-Ring Dynamics

PubMed Central

Marteyn, Benoit S.; Karimova, Gouzel; Fenton, Andrew K.; Gazi, Anastasia D.; West, Nicholas; Touqui, Lhousseine; Prevost, Marie-Christine; Betton, Jean-Michel; Poyraz, Oemer; Ladant, Daniel; Gerdes, Kenn; Sansonetti, Philippe J.; Tang, Christoph M.

2014-01-01

ABSTRACT Bacterial cell division requires the formation of a mature divisome complex positioned at the midcell. The localization of the divisome complex is determined by the correct positioning, assembly, and constriction of the FtsZ ring (Z-ring). Z-ring constriction control remains poorly understood and (to some extent) controversial, probably due to the fact that this phenomenon is transient and controlled by numerous factors. Here, we characterize ZapE, a novel ATPase found in Gram-negative bacteria, which is required for growth under conditions of low oxygen, while loss of zapE results in temperature-dependent elongation of cell shape. We found that ZapE is recruited to the Z-ring during late stages of the cell division process and correlates with constriction of the Z-ring. Overexpression or inactivation of zapE leads to elongation of Escherichia coli and affects the dynamics of the Z-ring during division. In vitro, ZapE destabilizes FtsZ polymers in an ATP-dependent manner. PMID:24595368

High molecular weight transglutaminase inhibitor produced by a microorganism (Streptomyces lavendulae Y-200).

PubMed

Ikura, K; Minami, K; Otomo, C; Hashimoto, H; Natsuka, S; Oda, K; Nakanishi, K

2000-01-01

Transglutaminases catalyze the cross-linking and amine incorporation of proteins, and are implicated in various biological phenomena such as blood clotting, wound healing, apoptosis, and cell differentiation. Streptomyces lavendulae Y-200, isolated from soil, produced a substance that inhibited transglutaminases. The inhibitory substance was purified from the cultured medium by procedures of acid precipitation, deoxyribonuclease treatment, and gel filtration chromatography. The partially purified sample was dark brown. The inhibitory activity was stable under acidic, alkaline, and high temperature conditions, and resistant to the treatment with proteinases such as trypsin and Pronase. The molecular weight of the inhibitory substance was estimated to be between 10(4) and 10(5) from its permeability through ultrafilter membranes. The acid hydrolysate of the inhibitory substance contained amino acids and sugars. The inhibitory substance inhibited both calcium-dependent and calcium-independent transglutaminases in a competitive manner with a glutamine substrate. The extent of inhibition caused by the calcium-dependent transglutaminase increased with increasing calcium concentration. The results obtained here may help identify a novel regulatory substance of transglutaminase in biological systems.

Plant Pathogenic Microbial Communication Affected by Elevated Temperature in Pectobacterium carotovorum subsp. carotovorum.

PubMed

Saha, N D; Chaudhary, A; Singh, S D; Singh, D; Walia, S; Das, T K

2015-11-01

Gram-negative plant pathogenic bacteria regulate specific gene expression in a population density-dependent manner by sensing level of Acyl-Homoserine Lactone (HSL) molecules which they produce and liberate to the environment, called Quorum Sensing (QS). The production of virulence factors (extracellular enzyme viz. cellulase, pectinase, etc.) in Pectobacterium carotovorum subsp. carotovorum (Pcc) is under strong regulation of QS. The QS signal molecule, N-(3-oxohexanoyl)-L-Homoserine Lactone (OHHL) was found as the central regulatory system for the virulence factor production in Pcc and is also under strict regulation of external environmental temperature. Under seven different incubation temperatures (24, 26, 28, 30, 33, 35, and 37 °C) in laboratory condition, highest amount of OHHL (804 violacein unit) and highest (79 %) Disease Severity Index (DSI) were measured at 33 °C. The OHHL production kinetics showed accumulation of highest concentration of OHHL at late log phase of the growth but diminution in the concentration occurred during stationary phase onwards to death phase. At higher temperature (35 and 37 °C) exposure, OHHL was not at detectable range. The effect of temperature on virulence factor production is the concomitant effect of HSL production and degradation which justifies less disease severity index in cross-inoculated tomato fruits incubated at 35 and 37 °C. The nondetection of the OHHL in the elevated temperature may because of degradation as these signal molecules are quite sensitive and prone to get degraded under different physical factors. This result provides the rationale behind the highest disease severity up to certain elevated temperature and leaves opportunities for investigation on mutation, co-evolution of superior plant pathogen with more stable HSL signals-mediated pathogenesis under global warming context.

Sealing Materials for Use in Vacuum at High Temperatures

NASA Technical Reports Server (NTRS)

Pettit, Donald R.; Camarda, Charles J.; Lee Vaughn, Wallace

2012-01-01

Sealing materials that can be applied and left in place in vacuum over a wide range of temperatures (especially temperatures of a few thousand degrees Celsius) have been conceived and investigated for potential utility in repairing thermal-protection tiles on the space shuttles in orbit before returning to Earth. These materials are also adaptable to numerous terrestrial applications that involve vacuum processing and/or repair of structures that must withstand high temperatures. These materials can be formulated to have mechanical handling characteristics ranging from almost freely flowing liquid-like consistency through paste-like consistency to stiff puttylike consistency, and to retain these characteristics in vacuum until heated to high curing temperatures. A sealing material of this type can be formulated to be used in any of several different ways for example, to be impregnated into a high-temperature-fabric patch, impregnated into a high-temperature-fabric gasket for sealing a patch, applied under a patch, or applied alone in the manner of putty or wallboard compound. The sealing material must be formulated to be compatible with, and adhere to, the structural material(s) to be repaired. In general, the material consists of a vacuum-compatible liquid containing one or more dissolved compound(s) and/or mixed with suspended solid particles. Depending on the intended application, the liquid can be chosen to be of a compound that can remain in place in vacuum for a time long enough to be useful, and/or to evaporate or decompose in a controlled way to leave a useful solid residue behind. The evaporation rate is determined by proper choice of vapor pressure, application of heat, and/or application of ultraviolet light or other optical radiation. The liquid chosen for the original space shuttle application is a commercial silicone vacuum-pump oil.

A spectrum of exercise training reduces soluble Aβ in a dose-dependent manner in a mouse model of Alzheimer's disease.

PubMed

Moore, Kaitlin M; Girens, Renee E; Larson, Sara K; Jones, Maria R; Restivo, Jessica L; Holtzman, David M; Cirrito, John R; Yuede, Carla M; Zimmerman, Scott D; Timson, Benjamin F

2016-01-01

Physical activity has long been hypothesized to influence the risk and pathology of Alzheimer's disease. However, the amount of physical activity necessary for these benefits is unclear. We examined the effects of three months of low and high intensity exercise training on soluble Aβ40 and Aβ42 levels in extracellular enriched fractions from the cortex and hippocampus of young Tg2576 mice. Low (LOW) and high (HI) intensity exercise training animals ran at speeds of 15m/min on a level treadmill and 32 m/min at a 10% grade, respectively for 60 min per day, five days per week, from three to six months of age. Sedentary mice (SED) were placed on a level, non-moving, treadmill for the same duration. Soleus muscle citrate synthase activity increased by 39% in the LOW group relative to SED, and by 71% in the HI group relative to LOW, indicating an exercise training effect in these mice. Soluble Aβ40 concentrations decreased significantly in an exercise training dose-dependent manner in the cortex. In the hippocampus, concentrations were decreased significantly in the HI group relative to LOW and SED. Soluble Aβ42 levels also decreased significantly in an exercise training dose-dependent manner in both the cortex and hippocampus. Five proteins involved in Aβ clearance (neprilysin, IDE, MMP9, LRP1 and HSP70) were elevated by exercise training with its intensity playing a role in each case. Our data demonstrate that exercise training reduces extracellular soluble Aβ in the brains of Tg2576 mice in a dose-dependent manner through an up-regulation of Aβ clearance. Copyright © 2015 Elsevier Inc. All rights reserved.

Repeated restraint stress enhances cue-elicited conditioned freezing and impairs acquisition of extinction in an age-dependent manner

PubMed Central

Zhang, Wei; Rosenkranz, J. Amiel

2013-01-01

Affective disorders are believed to involve dysfunction within the amygdala, a key structure for processing emotional information. Chronic stress may contribute to affective disorders such as depression and anxiety via its effects on the amygdala. Previous research has shown that chronic stress increases amygdala neuronal activity in an age-dependent manner. However, whether these distinct changes in amgydala neuronal activity are accompanied by age-dependent changes in amygdala-dependent affective behavior is unclear. In this study, we investigated how chronic stress impacts amgydala-dependent auditory fear conditioning in adolescent and adult rats in a repeated restraint model. We found that repeated restraint enhanced conditioned freezing in both adolescent and adult rats. But repeated restraint led to impaired acquisition of fear extinction only in adolescent rats. Along with previous findings, these results suggest that chronic stress may precipitate affective disorders via differential mechanisms, with different outcomes at different ages. PMID:23538069

Synthesis of cytochrome C oxidase 2: a p53-dependent metabolic regulator that promotes respiratory function and protects glioma and colon cancer cells from hypoxia-induced cell death.

PubMed

Wanka, C; Brucker, D P; Bähr, O; Ronellenfitsch, M; Weller, M; Steinbach, J P; Rieger, J

2012-08-16

P53 has an important role in the processing of starvation signals. P53-dependent molecular mediators of the Warburg effect reduce glucose consumption and promote mitochondrial function. We therefore hypothesized that the retention of wild-type p53 characteristic of primary glioblastomas limits metabolic demands induced by deregulated signal transduction in the presence of hypoxia and nutrient depletion. Here we report that short hairpin RNA-mediated gene suppression of wild-type p53 or ectopic expression of mutant temperature-sensitive dominant-negative p53(V135A) increased glucose consumption and lactate production, decreased oxygen consumption and enhanced hypoxia-induced cell death in p53 wild-type human glioblastoma cells. Similarly, genetic knockout of p53 in HCT116 colon carcinoma cells resulted in reduced respiration and hypersensitivity towards hypoxia-induced cell death. Further, wild-type p53 gene silencing reduced the expression of synthesis of cytochrome c oxidase 2 (SCO2), an effector necessary for respiratory chain function. An SCO2 transgene reverted the metabolic phenotype and restored resistance towards hypoxia in p53-depleted and p53 mutant glioma cells in a rotenone-sensitive manner, demonstrating that this effect was dependent on intact oxidative phosphorylation. Supplementation with methyl-pyruvate, a mitochondrial substrate, rescued p53 wild-type but not p53 mutant cells from hypoxic cell death, demonstrating a p53-mediated selective aptitude to metabolize mitochondrial substrates. Further, SCO2 gene silencing in p53 wild-type glioma cells sensitized these cells towards hypoxia. Finally, lentiviral gene suppression of SCO2 significantly enhanced tumor necrosis in a subcutaneous HCT116 xenograft tumor model, compatible with impaired energy metabolism in these cells. These findings demonstrate that glioma and colon cancer cells with p53 wild-type status can skew the Warburg effect and thereby reduce their vulnerability towards tumor hypoxia in an SCO2-dependent manner. Targeting SCO2 may therefore represent a valuable strategy to enhance sensitivity towards hypoxia and may complement strategies targeting glucose metabolism.

Uncertainty evaluation of thickness and warp of a silicon wafer measured by a spectrally resolved interferometer

NASA Astrophysics Data System (ADS)

Praba Drijarkara, Agustinus; Gergiso Gebrie, Tadesse; Lee, Jae Yong; Kang, Chu-Shik

2018-06-01

Evaluation of uncertainty of thickness and gravity-compensated warp of a silicon wafer measured by a spectrally resolved interferometer is presented. The evaluation is performed in a rigorous manner, by analysing the propagation of uncertainty from the input quantities through all the steps of measurement functions, in accordance with the ISO Guide to the Expression of Uncertainty in Measurement. In the evaluation, correlation between input quantities as well as uncertainty attributed to thermal effect, which were not included in earlier publications, are taken into account. The temperature dependence of the group refractive index of silicon was found to be nonlinear and varies widely within a wafer and also between different wafers. The uncertainty evaluation described here can be applied to other spectral interferometry applications based on similar principles.

Supercritical Fluid Extraction of Bioactive Compounds from Plant Materials.

PubMed

Wrona, Olga; Rafińska, Katarzyna; Możeński, Cezary; Buszewski, Bogusław

2017-11-01

There has been growing interest in the application of supercritical solvents over the last several years, many of the applications industrial in nature. The purpose of plant material extraction is to obtain large amounts of extract rich in the desired active compounds in a time-sensitive and cost-effective manner. The productivity and profitability of a supercritical fluid extraction (SFE) process largely depends on the selection of process parameters, which are elaborated upon in this paper. Carbon dioxide (CO2) is the most desirable solvent for the supercritical extraction of natural products. Its near-ambient critical temperature makes it suitable for the extraction of thermolabile components without degradation. A new approach has been adopted for SFE in which the solubility of nonpolar supercritical CO2 can be enhanced by the addition of small amounts of cosolvent.

Conceptual design of a divertor Thomson scattering diagnostic for NSTX-U

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

McLean, A. G., E-mail: mclean@fusion.gat.com; Soukhanovskii, V. A.; Allen, S. L.

2014-11-15

A conceptual design for a divertor Thomson scattering (DTS) diagnostic has been developed for the NSTX-U device to operate in parallel with the existing multipoint Thomson scattering system. Higher projected peak heat flux in NSTX-U will necessitate application of advanced magnetics geometries and divertor detachment. Interpretation and modeling of these divertor scenarios will depend heavily on local measurement of electron temperature, T{sub e}, and density, n{sub e}, which DTS provides in a passive manner. The DTS design for NSTX-U adopts major elements from the successful DIII-D DTS system including 7-channel polychromators measuring T{sub e} to 0.5 eV. If implemented onmore » NSTX-U, the divertor TS system would provide an invaluable diagnostic for the boundary program to characterize the edge plasma.« less

Chromatic Image Analysis For Quantitative Thermal Mapping

NASA Technical Reports Server (NTRS)

Buck, Gregory M.

1995-01-01

Chromatic image analysis system (CIAS) developed for use in noncontact measurements of temperatures on aerothermodynamic models in hypersonic wind tunnels. Based on concept of temperature coupled to shift in color spectrum for optical measurement. Video camera images fluorescence emitted by phosphor-coated model at two wavelengths. Temperature map of model then computed from relative brightnesses in video images of model at those wavelengths. Eliminates need for intrusive, time-consuming, contact temperature measurements by gauges, making it possible to map temperatures on complex surfaces in timely manner and at reduced cost.

One-step grafting of temperature-and pH-sensitive (N-vinylcaprolactam-co-4-vinylpyridine) onto silicone rubber for drug delivery

PubMed Central

Pino-Ramos, Victor H.; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

2017-01-01

Abstract A one-step method was implemented to graft N-vinylcaprolactam (NVCL) and 4-vinylpyridine (4VP) onto silicone rubber (SR) films using gamma radiation in order to endow the silicone surface with temperature- and pH-responsiveness, and give it the ability to host and release diclofenac in a controlled manner and thus prevent bacterial adhesion. The effects of radiation conditions (e.g., dose and monomers concentration) on the grafting percentage were evaluated, and the modified films were characterized by means of FTIR-ATR, Raman spectroscopy, calorimetry techniques (DSC and TGA) and contact angle measurements. The films responsiveness to stimuli was evaluated by recording the swelling degree of pristine and modified SR in buffer solutions (critical pH point) and as a function of changes in temperature (Upper Critical Solution Temperature, UCST). The graft copolymers of SR-g-(NVCL-co-4VP) showed good cytocompatibility against fibroblast cells for prolonged times, could host diclofenac and release it in a sustained manner for up to 24 h, and exhibited bacteriostatic activity when challenged against Escherichia coli. PMID:29491777

Immunostimulatory Activity of Opuntia ficus-indica var. Saboten Cladodes Fermented by Lactobacillus plantarum and Bacillus subtilis in RAW 264.7 Macrophages.

PubMed

Hwang, Joon-Ho; Lim, Sang-Bin

2017-02-01

To increase the functionality of Opuntia ficus-indica var. saboten cladodes, it was fermented by Lactobacillus plantarum and Bacillus subtilis. Eighty percent methanol extracts were investigated for their effects on nitric oxide (NO) production, cytokine secretion, nuclear factor-κB (NF-κB) activity, and mitogen-activated protein kinase (MAPK) phosphorylation in RAW 264.7 cells. Methanol extracts of L. plantarum culture medium (LPCME) and B. subtilis culture medium (BSCME) did not affect lipopolysaccharide (LPS)-induced NO production but, at 500 μg/mL, increased interferon (IFN)-γ-induced NO production by 55.2 and 66.5 μM, respectively, in RAW 264.7 cells. In RAW 264.7 cells not treated with LPS and IFN-γ, LPCME did not affect NO production, but BSCME increased NO production significantly in a dose-dependent manner. In addition, BSCME induced the expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in RAW 264.7 cells in a dose-dependent manner. BSCME at 500 μg/mL increased TNF-α and IL-1β mRNA levels by 83.8% and 82.2%, respectively. BSCME increased NF-κB-dependent luciferase activity in a dose-dependent manner; 500 μg/mL BSCME increased activity 9.1-fold compared with the control. BSCME induced the phosphorylation of p38, c-JUN NH 2 -terminal protein kinase (JNK), and extracellular signal-regulated kinase (ERK) in a dose-dependent manner, but did not affect total ERK levels. In conclusion, BSCME exerted immunostimulatory effects, which were mediated by MAPK phosphorylation and NF-κB activation, resulting in increased TNF-α and IL-1β gene expression in RAW 264.7 macrophages. Therefore, BSCM shows promise for use as an immunostimulatory therapeutic.

Can supine recovery mitigate the exercise intensity dependent attenuation of post-exercise heat loss responses?

PubMed

Kenny, Glen P; Gagnon, Daniel; Jay, Ollie; McInnis, Natalie H; Journeay, W Shane; Reardon, Francis D

2008-08-01

Cutaneous vascular conductance (CVC) and sweat rate are subject to non-thermal baroreflex-mediated attenuation post-exercise. Various recovery modalities have been effective in attenuating these decreases in CVC and sweat rate post-exercise. However, the interaction of recovery posture and preceding exercise intensity on post-exercise thermoregulation remains unresolved. We evaluated the combined effect of supine recovery and exercise intensity on post-exercise cardiovascular and thermal responses relative to an upright seated posture. Seven females performed 15 min of cycling ergometry at low- (LIE, 55% maximal oxygen consumption) or high-(HIE, 85% maximal oxygen consumption) intensity followed by 60 min of recovery in either an upright seated or supine posture. Esophageal temperature, CVC, sweat rate, cardiac output, stroke volume, heart rate, total peripheral resistance, and mean arterial pressure (MAP) were measured at baseline, at end-exercise, and at 2, 5, 12, 20, and every 10 min thereafter until the end of recovery. MAP and stroke volume were maintained during supine recovery to a greater extent relative to an upright seated recovery following HIE (p

On Noether's Theorem for the Invariant of the Time-Dependent Harmonic Oscillator

ERIC Educational Resources Information Center

Abe, Sumiyoshi; Itto, Yuichi; Matsunaga, Mamoru

2009-01-01

The time-dependent oscillator describing parametric oscillation, the concept of invariant and Noether's theorem are important issues in physics education. Here, it is shown how they can be interconnected in a simple and unified manner.

Effects of haloperidol on Kv4.3 potassium channels.

PubMed

Lee, Hong Joon; Sung, Ki-Wug; Hahn, Sang June

2014-10-05

Haloperidol is commonly used in clinical practice to treat acute and chronic psychosis, but it also has been associated with adverse cardiovascular events. We investigated the effects of haloperidol on Kv4.3 currents stably expressed in CHO cells using a whole-cell patch-clamp technique. Haloperidol did not significantly inhibit the peak amplitude of Kv4.3, but accelerated the decay rate of inactivation of Kv4.3 in a concentration-dependent manner. Thus, the effects of haloperidol on Kv4.3 were estimated from the integral of the Kv4.3 currents during the depolarization pulse. The Kv4.3 was decreased by haloperidol in a concentration-dependent manner with an IC50 value of 3.6 μM. Haloperidol accelerated the decay rate of Kv4.3 inactivation and activation kinetics in a concentration-dependent manner, thereby decreasing the time-to-peak. Haloperidol shifted the voltage dependence of the steady-state activation and inactivation of Kv4.3 in a hyperpolarizing direction. Haloperidol also caused an acceleration of the closed-state inactivation of Kv4.3. Haloperidol produced a use-dependent block of Kv4.3, which was accompanied by a slowing of recovery from the inactivation of Kv4.3. These results suggest that haloperidol blocks Kv4.3 by both interacting with the open state of Kv4.3 channels during depolarization and accelerating the closed-state inactivation at subthreshold membrane potentials. Copyright © 2014 Elsevier B.V. All rights reserved.

L-carnosine affects the growth of Saccharomyces cerevisiae in a metabolism-dependent manner.

PubMed

Cartwright, Stephanie P; Bill, Roslyn M; Hipkiss, Alan R

2012-01-01

The dipeptide L-carnosine (β-alanyl-L-histidine) has been described as enigmatic: it inhibits growth of cancer cells but delays senescence in cultured human fibroblasts and extends the lifespan of male fruit flies. In an attempt to understand these observations, the effects of L-carnosine on the model eukaryote, Saccharomyces cerevisiae, were examined on account of its unique metabolic properties; S. cerevisiae can respire aerobically, but like some tumor cells, it can also exhibit a metabolism in which aerobic respiration is down regulated. L-Carnosine exhibited both inhibitory and stimulatory effects on yeast cells, dependent upon the carbon source in the growth medium. When yeast cells were not reliant on oxidative phosphorylation for energy generation (e.g. when grown on a fermentable carbon source such as 2% glucose), 10-30 mM L-carnosine slowed growth rates in a dose-dependent manner and increased cell death by up to 17%. In contrast, in media containing a non-fermentable carbon source in which yeast are dependent on aerobic respiration (e.g. 2% glycerol), L-carnosine did not provoke cell death. This latter observation was confirmed in the respiratory yeast, Pichia pastoris. Moreover, when deletion strains in the yeast nutrient-sensing pathway were treated with L-carnosine, the cells showed resistance to its inhibitory effects. These findings suggest that L-carnosine affects cells in a metabolism-dependent manner and provide a rationale for its effects on different cell types.

Primary alcohols activate human TRPA1 channel in a carbon chain length-dependent manner.

PubMed

Komatsu, Tomoko; Uchida, Kunitoshi; Fujita, Fumitaka; Zhou, Yiming; Tominaga, Makoto

2012-04-01

Transient receptor potential ankyrin 1 (TRPA1) is a calcium-permeable non-selective cation channel that is mainly expressed in primary nociceptive neurons. TRPA1 is activated by a variety of noxious stimuli, including cold temperatures, pungent compounds such as mustard oil and cinnamaldehyde, and intracellular alkalization. Here, we show that primary alcohols, which have been reported to cause skin, eye or nasal irritation, activate human TRPA1 (hTRPA1). We measured intracellular Ca(2+) changes in HEK293 cells expressing hTRPA1 induced by 1 mM primary alcohols. Higher alcohols (1-butanol to 1-octanol) showed Ca(2+) increases proportional to the carbon chain length. In whole-cell patch-clamp recordings, higher alcohols (1-hexanol to 1-octanol) activated hTRPA1 and the potency increased with the carbon chain length. Higher alcohols evoked single-channel opening of hTRPA1 in an inside-out configuration. In addition, cysteine at 665 in the N terminus and histidine at 983 in the C terminus were important for hTRPA1 activation by primary alcohols. Furthermore, straight-chain secondary alcohols increased intracellular Ca(2+) concentrations in HEK293 cells expressing hTRPA1, and both primary and secondary alcohols showed hTRPA1 activation activities that correlated highly with their octanol/water partition coefficients. On the other hand, mouse TRPA1 did not show a strong response to 1-hexanol or 1-octanol, nor did these alcohols evoke significant pain in mice. We conclude that primary and secondary alcohols activate hTRPA1 in a carbon chain length-dependent manner. TRPA1 could be a sensor of alcohols inducing skin, eye and nasal irritation in human.

The potential use of physical resilience to predict healthy aging.

PubMed

Schorr, Anna; Carter, Christy; Ladiges, Warren

2018-01-01

Physical resilience is the ability of an organism to respond to stressors that acutely disrupt normal physiological homeostasis. By definition, resilience decreases with increasing age, while frailty, defined as a decline in tissue function, increases with increasing age. Assessment of resilience could therefore be an informative early paradigm to predict healthy aging compared to frailty, which measures late life dysfunction. Parameters for resilience in the laboratory mouse are not yet well defined, and no single standardized stress test exists. Since aging involves multiple genetic pathways, integrative responses involving multiple tissues, organs, and activities need to be measured to reveal the overall resilience status, suggesting a battery of stress tests, rather than a single all-encompassing one, would be most informative. Three simple, reliable, and inexpensive stressors are described in this review that could be used as a panel to determine levels of resilience. Brief cold water immersion allows a recovery time to normothermia as an indicator of resilience to hypothermia, i.e. the quicker the return to normal body temperature, the more robust the resilience. Sleep deprivation (SD) impairs remote memory in aged mice, and has detrimental effects on glucose metabolism. Cyclophosphamide (CYP) targets white blood cells, especially myeloid cells resulting in neutropenia with a rebound neutrophilia in an age-dependent manner. Thus a strong neutrophilic response indicates resilience. In conclusion, resilience promises to be an especially useful measurement of biological age, i.e. how fast a particular organ or tissue ages. The three stressors, cold, SD, and CYP, are applicable to human medicine and aging because they represent clinically relevant stress conditions that have effects in an age-dependent manner. They are thus an attractive perturbation for resilience testing in mice to measure the effectiveness of interventions that target basic aging processes.

Retinohypothalamic Tract Synapses in the Rat Suprachiasmatic Nucleus Demonstrate Short-Term Synaptic Plasticity

PubMed Central

Moldavan, Mykhaylo G.

2010-01-01

The master circadian pacemaker located in the suprachiasmatic nucleus (SCN) is entrained by light intensity–dependent signals transmitted via the retinohypothalamic tract (RHT). Short-term plasticity at glutamatergic RHT–SCN synapses was studied using stimulus frequencies that simulated the firing of light sensitive retinal ganglion cells. The evoked excitatory postsynaptic current (eEPSC) was recorded from SCN neurons located in hypothalamic brain slices. The eEPSC amplitude was stable during 0.08 Hz stimulation and exhibited frequency-dependent short-term synaptic depression (SD) during 0.5 to 100 Hz stimulus trains in 95 of 99 (96%) recorded neurons. During SD the steady-state eEPSC amplitude decreased, whereas the cumulative charge transfer increased in a frequency-dependent manner and saturated at 20 Hz. SD was similar during subjective day and night and decreased with increasing temperature. Paired-pulse stimulation (PPS) and voltage-dependent Ca2+ channel (VDCC) blockers were used to characterize a presynaptic release mechanism. Facilitation was present in 30% and depression in 70% of studied neurons during PPS. Synaptic transmission was reduced by blocking both N- and P/Q-type presynaptic VDCCs, but only the N-type channel blocker significantly relieved SD. Aniracetam inhibited AMPA receptor desensitization but did not alter SD. Thus we concluded that SD is the principal form of short-term plasticity at RHT synapses, which presynaptically and frequency-dependently attenuates light-induced glutamatergic RHT synaptic transmission protecting SCN neurons against excessive excitation. PMID:20220078

TALE activators regulate gene expression in a position- and strand-dependent manner in mammalian cells.

PubMed

Uhde-Stone, Claudia; Cheung, Edna; Lu, Biao

2014-01-24

Transcription activator-like effectors (TALEs) are a class of transcription factors that are readily programmable to regulate gene expression. Despite their growing popularity, little is known about binding site parameters that influence TALE-mediated gene activation in mammalian cells. We demonstrate that TALE activators modulate gene expression in mammalian cells in a position- and strand-dependent manner. To study the effects of binding site location, we engineered TALEs customized to recognize specific DNA sequences located in either the promoter or the transcribed region of reporter genes. We found that TALE activators robustly activated reporter genes when their binding sites were located within the promoter region. In contrast, TALE activators inhibited the expression of reporter genes when their binding sites were located on the sense strand of the transcribed region. Notably, this repression was independent of the effector domain utilized, suggesting a simple blockage mechanism. We conclude that TALE activators in mammalian cells regulate genes in a position- and strand-dependent manner that is substantially different from gene activation by native TALEs in plants. These findings have implications for optimizing the design of custom TALEs for genetic manipulation in mammalian cells. Copyright © 2013 Elsevier Inc. All rights reserved.

ERβ1 inhibits the migration and invasion of breast cancer cells through upregulation of E-cadherin in a Id1-dependent manner

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

Zhou, Yan; Ming, Jia; Xu, Yan

2015-02-06

Highlights: • Expression of ERβ1 was positively correlated with E-cadherin in breast cancer cell. • ERβ1 upregulates E-cadherin expression in breast cancer cell lines. • ERβ1 upregulates E-cadherin expression in a Id1-dependent manner. - Abstract: ERβ1 is a member of the nuclear receptor superfamily of ligand-regulated transcription factors. It plays an important role in regulating the progression of breast cancer. However, the mechanisms of ERβ1 in tumorigenesis, metastasis and prognosis are still not fully clear. In this study, we showed that the expression of ERβ1 was positively correlated with E-cadherin expression in breast cancer cell lines. In addition, we foundmore » that ERβ1 upregulates E-cadherin expression in breast cancer cell lines. Furthermore, we also found that ERβ1 inhibits the migration and invasion of breast cancer cells and upregulated E-cadherin expression in a Id1-dependent manner. Taken together, our study provides further understanding of the molecular mechanism of ERβ1 in tumor metastasis and suggests the feasibility of developing novel therapeutic approaches to target Id1 to inhibit breast cancer metastasis.« less

Root Zone Respiration on Hydroponically Grown Wheat Plant Systems

NASA Technical Reports Server (NTRS)

Soler-Crespo, R. A.; Monje, O. A.

2010-01-01

Root respiration is a biological phenomenon that controls plant growth and physiological development during a plant's lifespan. This process is dependent on the availability of oxygen in the system where the plant is located. In hydroponic systems, where plants are submerged in a solution containing vital nutrients but no type of soil, the availability of oxygen arises from the dissolved oxygen concentration in the solution. This oxygen concentration is dependent on the , gas-liquid interface formed on the upper surface of the liquid, as given by Henry's Law, depending on pressure and temperature conditions. Respiration rates of the plants rise as biomass and root zone increase with age. The respiration rate of Apogee wheat plants (Triticum aestivum) was measured as a function of light intensity (catalytic for photosynthesis) and CO2 concentration to determine their effect on respiration rates. To determine their effects on respiration rate and plant growth microbial communities were introduced into the system, by Innoculum. Surfactants were introduced, simulating gray-water usage in space, as another factor to determine their effect on chemical oxygen demand of microbials and on respiration rates of the plants. It is expected to see small effects from changes in CO2 concentration or light levels, and to see root respiration decrease in an exponential manner with plant age and microbial activity.

On the mechanism for PPAR agonists to enhance ABCA1 gene expression

PubMed Central

Ogata, Masaki; Tsujita, Maki; Hossain, Mohammad Anwar; Akita, Nobukatsu; Gonzalez, Frank J.; Staels, Bart; Suzuki, Shogo; Fukutomi, Tatsuya; Kimura, Genjiro; Yokoyama, Shinji

2009-01-01

Expression of ATP binding cassette transporter A1 (ABCA1), a major regulator of high density lipoprotein (HDL) biogenesis, is known to be up-regulated by the transcription factor liver X receptor (LXR) α, and expression is further enhanced by activation of the peroxisome proliferator activated receptors (PPARs). We investigated this complex regulatory network using specific PPAR agonists: four fibrates (fenofibrate, bezafibrate, gemfibrozil and LY518674), a PPAR δ agonist (GW501516) and a PPAR γ agonist (pioglitazone). All of these compounds increased the expression of LXRs, PPARs and ABCA1 mRNAs, and associated apoA-I-mediated lipid release in THP-1 macrophage, WI38 fibroblast and mouse fibroblast. When mouse fibroblasts lacking expression of PPAR α were examined, the effects of fenofibrate and LY518674 were markedly diminished while induction by other ligands were retained. The PPAR α promoter was activated by all of these compounds in an LXR α-dependent manner, and partially in a PPAR α-dependent manner, in mouse fibroblast. The LXR responsive element (LXRE)-luciferase activity was enhanced by all the compounds in an LXR α-dependent manner in mouse fibroblast. This activation was exclusively PPAR α-dependent by fenofibrate and LY518674, but nonexclusively by the others. We conclude that PPARs and LXRs are involved in the regulation of ABCA1 expression and HDL biogenesis in a cooperative signal transduction pathway. PMID:19201410

Regulation of alternative splicing by the circadian clock and food related cues

PubMed Central

2012-01-01

Background The circadian clock orchestrates daily rhythms in metabolism, physiology and behaviour that allow organisms to anticipate regular changes in their environment, increasing their adaptation. Such circadian phenotypes are underpinned by daily rhythms in gene expression. Little is known, however, about the contribution of post-transcriptional processes, particularly alternative splicing. Results Using Affymetrix mouse exon-arrays, we identified exons with circadian alternative splicing in the liver. Validated circadian exons were regulated in a tissue-dependent manner and were present in genes with circadian transcript abundance. Furthermore, an analysis of circadian mutant Vipr2-/- mice revealed the existence of distinct physiological pathways controlling circadian alternative splicing and RNA binding protein expression, with contrasting dependence on Vipr2-mediated physiological signals. This view was corroborated by the analysis of the effect of fasting on circadian alternative splicing. Feeding is an important circadian stimulus, and we found that fasting both modulates hepatic circadian alternative splicing in an exon-dependent manner and changes the temporal relationship with transcript-level expression. Conclusions The circadian clock regulates alternative splicing in a manner that is both tissue-dependent and concurrent with circadian transcript abundance. This adds a novel temporal dimension to the regulation of mammalian alternative splicing. Moreover, our results demonstrate that circadian alternative splicing is regulated by the interaction between distinct physiological cues, and illustrates the capability of single genes to integrate circadian signals at different levels of regulation. PMID:22721557

Non-specific actions of the non-peptide tachykinin receptor antagonists, CP-96,345, RP 67580 and SR 48968, on neurotransmission.

PubMed Central

Wang, Z. Y.; Tung, S. R.; Strichartz, G. R.; Håkanson, R.

1994-01-01

1. Three non-peptide tachykinin receptor antagonists, CP-96,345, RP 67580 and SR 48968, were found to inhibit the electrically-evoked, tachykinin-mediated contractile responses of the rabbit iris sphincter in a concentration-dependent fashion; the pIC50 values were 5.6 +/- 0.01, 5.4 +/- 0.07 and 4.8 +/- 0.03, respectively. 2. These antagonists also inhibited the electrically-evoked, parasympathetic response of the rabbit iris sphincter and the sympathetic response of the guinea-pig vas deferens in a concentration-dependent manner; the pIC50 values were 0.3-1.2 log units lower than those recorded for the tachykinin-mediated responses. 3. Two local anaesthetics, bupivacaine and oxybuprocaine, were also found to inhibit the tachykinin-mediated, cholinergic and sympathetic contractile responses in these tissues in a concentration-dependent manner; the concentration ranges for producing the inhibition were similar to those of the non-peptide tachykinin receptor antagonists. 4. On the sciatic nerves of frogs, the tachykinin receptor antagonists inhibited action potentials in a concentration-dependent manner; the potency of the three drugs was similar to that of bupivacaine. 5. Our results suggest that, in addition to blocking tachykinin receptors, the non-peptide tachykinin receptor antagonists, CP-96,345, RP 67580 and SR 48968, may exert non-specific inhibitory effects on neurotransmission. PMID:8012694

New insight into mitochondrial changes in vascular endothelial cells irradiated by gamma ray.

PubMed

Hu, Shunying; Gao, Yajing; Zhou, Hao; Kong, Fanxuan; Xiao, Fengjun; Zhou, Pingkun; Chen, Yundai

2017-05-01

To investigate alterations of mitochondria in irradiated endothelial cells to further elucidate the mechanism underlying radiation-induced heart disease. Experiments were performed using human umbilical vein endothelial cells (HUVECs). HUVECs were irradiated with single gamma ray dose of 0, 5, 10 and 20 Gy, respectively. Apoptosis was assessed by flow cytometry at 24, 48 and 72 h post-irradiation, respectively. The intracellular reactive oxygen species (ROS) was measured with 2',7'-dichlorofluorescein-diacetate (DCFH-DA) at 24 h post-irradiation. Mitochondrial membrane potential (ΔΨm) by JC-1 and the opening of mitochondrial permeability transition pore (mPTP) by a calcein-cobalt quenching method were detected at 24 h post-irradiation in order to measure changes of mitochondria induced by gamma ray irradiation. Gamma ray irradiation increased HUVECs apoptosis in a dose-dependent and time-dependent manner. Irradiation also promoted ROS production in HUVECs in a dose-dependent manner. At 24 h post-irradiation, the results showed that irradiation decreases ΔΨm, however, paradoxically, flow cytometry showed green fluorescence instensity higher in irradiated HUVECs than in control HUVECs in an irradiation dose-dependent manner which indicated gamma ray irradiation inhibited mPTP opening in HUVECs. Gamma ray irradiation induces apoptosis and ROS production of endothelial cells, and decreases ΔΨm meanwhile contradictorily inhibiting the opening of mPTP.

Iron alters cell survival in a mitochondria-dependent pathway in ovarian cancer cells

PubMed Central

Bauckman, Kyle; Haller, Edward; Taran, Nicholas; Rockfield, Stephanie; Ruiz-Rivera, Abigail; Nanjundan, Meera

2015-01-01

The role of iron in the development of cancer remains unclear. We previously reported that iron reduces cell survival in a Ras/mitogen-activated protein kinase (MAPK)-dependent manner in ovarian cells; however, the underlying downstream pathway leading to reduced survival was unclear. Although levels of intracellular iron, ferritin/CD71 protein and reactive oxygen species did not correlate with iron-induced cell survival changes, we identified mitochondrial damage (via TEM) and reduced expression of outer mitochondrial membrane proteins (translocase of outer membrane: TOM20 and TOM70) in cell lines sensitive to iron. Interestingly, Ru360 (an inhibitor of the mitochondrial calcium uniporter) reversed mitochondrial changes and restored cell survival in HEY ovarian carcinoma cells treated with iron. Further, cells treated with Ru360 and iron also had reduced autophagic punctae with increased lysosomal numbers, implying cross-talk between these compartments. Mitochondrial changes were dependent on activation of the Ras/MAPK pathway since treatment with a MAPK inhibitor restored expression of TOM20/TOM70 proteins. Although glutathione antioxidant levels were reduced in HEY treated with iron, extracellular glutamate levels were unaltered. Strikingly, oxalomalate (inhibitor of aconitase, involved in glutamate production) reversed iron-induced responses in a similar manner to Ru360. Collectively, our results implicate iron in modulating cell survival in a mitochondria-dependent manner in ovarian cancer cells. PMID:25697096

Effect of Simulated Climate Warming on the Ectomycorrhizal Fungal Community of Boreal and Temperate Host Species Growing Near Their Shared Ecotonal Range Limits.

PubMed

Mucha, Joanna; Peay, Kabir G; Smith, Dylan P; Reich, Peter B; Stefański, Artur; Hobbie, Sarah E

2018-02-01

Ectomycorrhizal (ECM) fungi can influence the establishment and performance of host species by increasing nutrient and water absorption. Therefore, understanding the response of ECM fungi to expected changes in the global climate is crucial for predicting potential changes in the composition and productivity of forests. While anthropogenic activity has, and will continue to, cause global temperature increases, few studies have investigated how increases in temperature will affect the community composition of ectomycorrhizal fungi. The effects of global warming are expected to be particularly strong at biome boundaries and in the northern latitudes. In the present study, we analyzed the effects of experimental manipulations of temperature and canopy structure (open vs. closed) on ectomycorrhizal fungi identified from roots of host seedlings through 454 pyrosequencing. The ecotonal boundary site selected for the study was between the southern boreal and temperate forests in northern Minnesota, USA, which is the southern limit range for Picea glauca and Betula papyrifera and the northern one for Pinus strobus and Quercus rubra. Manipulations that increased air and soil temperature by 1.7 and 3.4 °C above ambient temperatures, respectively, did not change ECM richness but did alter the composition of the ECM community in a manner dependent on host and canopy structure. The prediction that colonization of boreal tree species with ECM symbionts characteristic of temperate species would occur was not substantiated. Overall, only a small proportion of the ECM community appears to be strongly sensitive to warming.

A Simulated Heat Wave Has Diverse Effects on Immune Function and Oxidative Physiology in the Corn Snake (Pantherophis guttatus).

PubMed

Stahlschmidt, Z R; French, S S; Ahn, A; Webb, A; Butler, M W

Animals will continue to encounter increasingly warm environments, including more frequent and intense heat waves. Yet the physiological consequences of heat waves remain equivocal, potentially because of variation in adaptive plasticity (reversible acclimation) and/or aspects of experimental design. Thus, we measured a suite of physiological variables in the corn snake (Pantherophis guttatus) after exposure to field-parameterized, fluctuating temperature regimes (moderate temperature and heat wave treatments) to address two hypotheses: (1) a heat wave causes physiological stress, and (2) thermal performance of immune function exhibits adaptive plasticity in response to a heat wave. We found little support for our first hypothesis because a simulated heat wave had a negative effect on body mass, but it also reduced oxidative damage and did not affect peak performance of three immune metrics. Likewise, we found only partial support for our second hypothesis. After exposure to a simulated heat wave, P. guttatus exhibited greater performance breadth and reduced temperature specialization (the standardized difference between peak performance and performance breadth) for only one of three immune metrics and did so in a sex-dependent manner. Further, a simulated heat wave did not elicit greater performance of any immune metric at higher temperatures. Yet a heat wave likely reduced innate immune function in P. guttatus because each metric of innate immune performance in this species (as in most vertebrates) was lower at elevated temperatures. Together with previous research, our study indicates that a heat wave may have complex, modest, and even positive physiological effects in some taxa.

pH and temperature dual-sensitive liposome gel based on novel cleavable mPEG-Hz-CHEMS polymeric vaginal delivery system

PubMed Central

Chen, Daquan; Sun, Kaoxiang; Mu, Hongjie; Tang, Mingtan; Liang, Rongcai; Wang, Aiping; Zhou, Shasha; Sun, Haijun; Zhao, Feng; Yao, Jianwen; Liu, Wanhui

2012-01-01

Background In this study, a pH and temperature dual-sensitive liposome gel based on a novel cleavable hydrazone-based pH-sensitive methoxy polyethylene glycol 2000-hydrazone-cholesteryl hemisuccinate (mPEG-Hz-CHEMS) polymer was used for vaginal administration. Methods The pH-sensitive, cleavable mPEG-Hz-CHEMS was designed as a modified pH-sensitive liposome that would selectively degrade under locally acidic vaginal conditions. The novel pH-sensitive liposome was engineered to form a thermogel at body temperature and to degrade in an acidic environment. Results A dual-sensitive liposome gel with a high encapsulation efficiency of arctigenin was formed and improved the solubility of arctigenin characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dual-sensitive liposome gel with a sol-gel transition at body temperature was degraded in a pH-dependent manner, and was stable for a long period of time at neutral and basic pH, but cleavable under acidic conditions (pH 5.0). Arctigenin encapsulated in a dual-sensitive liposome gel was more stable and less toxic than arctigenin loaded into pH-sensitive liposomes. In vitro drug release results indicated that dual-sensitive liposome gels showed constant release of arctigenin over 3 days, but showed sustained release of arctigenin in buffers at pH 7.4 and pH 9.0. Conclusion This research has shed some light on a pH and temperature dual-sensitive liposome gel using a cleavable mPEG-Hz-CHEMS polymer for vaginal delivery. PMID:22679372

Mechanical Characterization of Thermomechanical Matrix Residual Stresses Incurred During MMC Processing

NASA Technical Reports Server (NTRS)

Castelli, Michael G.

1998-01-01

In recent years, much effort has been spent examining the residual stress-strain states of advanced composites. Such examinations are motivated by a number of significant concerns that affect composite development, processing, and analysis. The room-temperature residual stress states incurred in many advanced composite systems are often quite large and can introduce damage even prior to the first external mechanical loading of the material. These stresses, which are induced during the cooldown following high-temperature consolidation, result from the coefficient of thermal expansion mismatch between the fiber and matrix. Experimental techniques commonly used to evaluate composite internal residual stress states are non-mechanical in nature and generally include forms of x-ray and neutron diffraction. Such approaches are usually complex, involving a number of assumptions and limitations associated with a wide range of issues, including the depth of penetration, the volume of material being assessed, and erroneous effects associated with oriented grains. Furthermore, and more important to the present research, these techniques can assess only "single time" stress in the composite. That is, little, if any, information is obtained that addresses the time-dependent point at which internal stresses begin to accumulate, the manner in which the accumulation occurs, and the presiding relationships between thermoelastic, thermoplastic, and thermoviscous behaviors. To address these critical issues, researchers at the NASA Lewis Research Center developed and implemented an innovative mechanical test technique to examine in real time, the time-dependent thermomechanical stress behavior of a matrix alloy as it went through a consolidation cycle.

Effects of temperature on consumer-resource interactions.

PubMed

Amarasekare, Priyanga

2015-05-01

Understanding how temperature variation influences the negative (e.g. self-limitation) and positive (e.g. saturating functional responses) feedback processes that characterize consumer-resource interactions is an important research priority. Previous work on this topic has yielded conflicting outcomes with some studies predicting that warming should increase consumer-resource oscillations and others predicting that warming should decrease consumer-resource oscillations. Here, I develop a consumer-resource model that both synthesizes previous findings in a common framework and yields novel insights about temperature effects on consumer-resource dynamics. I report three key findings. First, when the resource species' birth rate exhibits a unimodal temperature response, as demonstrated by a large number of empirical studies, the temperature range over which the consumer-resource interaction can persist is determined by the lower and upper temperature limits to the resource species' reproduction. This contrasts with the predictions of previous studies, which assume that the birth rate exhibits a monotonic temperature response, that consumer extinction is determined by temperature effects on consumer species' traits, rather than the resource species' traits. Secondly, the comparative analysis I have conducted shows that whether warming leads to an increase or decrease in consumer-resource oscillations depends on the manner in which temperature affects intraspecific competition. When the strength of self-limitation increases monotonically with temperature, warming causes a decrease in consumer-resource oscillations. However, if self-limitation is strongest at temperatures physiologically optimal for reproduction, a scenario previously unanalysed by theory but amply substantiated by empirical data, warming can cause an increase in consumer-resource oscillations. Thirdly, the model yields testable comparative predictions about consumer-resource dynamics under alternative hypotheses for how temperature affects competitive and resource acquisition traits. Importantly, it does so through empirically quantifiable metrics for predicting temperature effects on consumer viability and consumer-resource oscillations, which obviates the need for parameterizing complex dynamical models. Tests of these metrics with empirical data on a host-parasitoid interaction yield realistic estimates of temperature limits for consumer persistence and the propensity for consumer-resource oscillations, highlighting their utility in predicting temperature effects, particularly warming, on consumer-resource interactions in both natural and agricultural settings. © 2014 The Author. Journal of Animal Ecology © 2014 British Ecological Society.

Alginate-Encapsulation for the Improved Hypothermic Preservation of Human Adipose-Derived Stem Cells.

PubMed

Swioklo, Stephen; Constantinescu, Andrei; Connon, Che J

2016-03-01

Despite considerable progress within the cell therapy industry, unmet bioprocessing and logistical challenges associated with the storage and distribution of cells between sites of manufacture and the clinic exist. We examined whether hypothermic (4°C-23°C) preservation of human adipose-derived stem cells could be improved through their encapsulation in 1.2% calcium alginate. Alginate encapsulation improved the recovery of viable cells after 72 hours of storage. Viable cell recovery was highly temperature-dependent, with an optimum temperature of 15°C. At this temperature, alginate encapsulation preserved the ability for recovered cells to attach to tissue culture plastic on rewarming, further increasing its effect on total cell recovery. On attachment, the cells were phenotypically normal, displayed normal growth kinetics, and maintained their capacity for trilineage differentiation. The number of cells encapsulated (up to 2 × 10(6) cells per milliliter) did not affect viable cell recovery nor did storage of encapsulated cells in a xeno-free, serum-free,current Good Manufacturing Practice-grade medium. We present a simple, low-cost system capable of enhancing the preservation of human adipose-derived stem cells stored at hypothermic temperatures, while maintaining their normal function. The storage of cells in this manner has great potential for extending the time windows for quality assurance and efficacy testing, distribution between the sites of manufacture and the clinic, and reducing the wastage associated with the limited shelf life of cells stored in their liquid state. ©AlphaMed Press.

Superfluid density and condensate fraction in the BCS-BEC crossover regime at finite temperatures

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

Fukushima, N.; Ohashi, Y.; Faculty of Science and Technology, Keio University, Hiyoshi, Yokohama 223

2007-03-15

The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density {rho}{sub s} in the BCS-BEC crossover regime of a uniform superfluid Fermi gas at finite temperatures. We include strong-coupling or fluctuation effects on these quantities within a Gaussian approximation. We also incorporate the same fluctuation effects into the BCS single-particle excitations described by the superfluid order parameter {delta} and Fermi chemical potential {mu}, using the Nozieres-Schmitt-Rink approximation. This treatment is shown to be necessary for consistent treatment of {rho}{sub s} over themore » entire BCS-BEC crossover. We also calculate the condensate fraction N{sub c} as a function of the temperature, a quantity which is quite different from the superfluid density {rho}{sub s}. We show that the mean-field expression for the condensate fraction N{sub c} is a good approximation even in the strong-coupling BEC regime. Our numerical results show how {rho}{sub s} and N{sub c} depend on temperature, from the weak-coupling BCS region to the BEC region of tightly bound Cooper pair molecules. In a companion paper [Phys. Rev. A 74, 063626 (2006)], we derive an equivalent expression for {rho}{sub s} from the thermodynamic potential, which exhibits the role of the pairing fluctuations in a more explicit manner.« less

Temperature determines size and direction of effects of elevated CO2 and nitrogen form on yield quantity and quality of Chinese cabbage.

PubMed

Reich, M; van den Meerakker, A N; Parmar, S; Hawkesford, M J; De Kok, L J

2016-01-01

Rising atmospheric CO2 concentrations (e[CO2 ]) are presumed to have a significant impact on plant growth and yield and also on mineral nutrient composition, and therefore, on nutritional quality of crops and vegetables. To assess the relevance of these effects in future agroecosystems it is important to understand how e[CO2 ] interacts with other environmental factors. In the present study, we examined the interactive effects of e[CO2 ] with temperature and the form in which nitrogen is supplied (nitrate or ammonium nitrate) on growth, amino acid content and mineral nutrient composition of Chinese cabbage (Brassica pekinensis Rupr.), a crop characterised by its high nutritional value and increasing relevance for human nutrition in many developing countries. Higher temperature, ammonium nitrate and e[CO2 ] had a positive impact on net photosynthesis and growth. A stimulating effect of e[CO2 ] on growth was only observed if the temperature was high (21/18 °C, day/night), and an interaction of e[CO2 ] with N form was only observed if the temperature was ambient (15/12 °C, day/night). Mineral nutrient composition was affected in a complex manner by all three factors and their interaction. These results demonstrate how much the effect of e[CO2 ] on mineral quality of crops depends on other environmental factors. Changes in temperature, adapting N fertilisation and the oxidation state of N have the potential to counteract the mineral depletion caused by e[CO2 ]. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Sliding temperatures of ice skates

NASA Astrophysics Data System (ADS)

Colbeck, S. C.; Najarian, L.; Smith, H. B.

1997-06-01

The two theories developed to explain the low friction of ice, pressure melting and frictional heating, require opposite temperature shifts at the ice-skate interface. The arguments against pressure melting are strong, but only theoretical. A set of direct temperature measurements shows that frictional heating is the dominant mechanism because temperature behaves in the manner predicted by the theory of frictional heating. Like snow skis, ice skates are warmed by sliding and then cool when the sliding stops. The temperature increases with speed and with thermal insulation. The sliding leaves a warm track on the ice surface behind the skate and the skate sprays warm ejecta.

Implications from Meteoric and Volcanic Infrasound Measured in the Netherlands

NASA Astrophysics Data System (ADS)

Evers, L.

2003-12-01

Infrasound observations started in the Netherlands in 1986. Since then, several array configurations and instruments have been developed, tested and made operational. Currently, three infrasound arrays are continuously measuring infrasound with in-house developed microbarometers. The array apertures vary from 30 to 1500 meters and the number of instruments from 6 to 16 microbarometers. The inter-array distance ranges from 50 up to 150 km. This dense network of infrasound arrays is used to distinguish between earthquakes and sources in the atmosphere. Sonic booms, for example, can be experienced in the same manner as small (gas induced) earthquakes. Furthermore, Comprehensive Nuclear-Test-Ban Treaty (CTBT) related research is done. Meteors are one of the few natural impulsive sources generating energy in kT TNT equivalent range. Therefore, the study of meteors is essential to the CTBT where infrasound is applied as monitoring technique. Studies of meteors in the Netherlands have shown the capability of infrasound to trace a meteor through the stratosphere. The propagation of infrasound is in first order dependent on the wind and temperature structure of the atmosphere. The meteor's path could be reconstructed by using ECMWF atmospheric models for wind and temperature. The results were compared to visual observations, confirming the location, direction and reported origin time. The accuracy of the localization mainly depends on the applied atmospheric model and array resolution. Successfully applying infrasound depends on the array configuration that should be based on the -frequency depend- spatial coherence of the signals of interest. The array aperture and inter-element distance will play a decisive role in detecting low signal-to-noise ratios. This is shown by results from studies on volcanic infrasound from Mt. Etna (Italy) detected in the Netherlands. Sub-array processing on the 16 element array revealed an increased detectability of infrasound for small aperture, 800 m, arrays, compared to large aperture, 1500 m, arrays.

NRIP enhances HPV gene expression via interaction with either GR or E2

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

Chang, Szu-Wei; Lu, Pei-Yu; Guo, Jih-Huong

We previously identified a gene, nuclear receptor-interaction protein (NRIP), which functions as a transcription cofactor in glucocorticoid receptor (GR) and human papillomavirus E2 (HPV E2)-driven gene expression. Here, we comprehensively evaluated the role of NRIP in HPV-16 gene expression. NRIP acts as a transcription cofactor to enhance GR-regulated HPV-16 gene expression in the presence of hormone. NRIP also can form complex with E2 that caused NRIP-induced HPV gene expression via E2-binding sites in a hormone-independent manner. Furthermore, NRIP can associate with GR and E2 to form tri-protein complex to activate HPV gene expression via GRE, not the E2-binding site, inmore » a hormone-dependent manner. These results indicate that NRIP and GR are viral E2-binding proteins and that NRIP regulates HPV gene expression via GRE and/or E2 binding site in the HPV promoter in a hormone-dependent or independent manner, respectively.« less

Arginase inhibition reduces interleukin-1β-stimulated vascular smooth muscle cell proliferation by increasing nitric oxide synthase-dependent nitric oxide production

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

Yoon, Jeongyeon; Ryoo, Sungwoo, E-mail: ryoosw08@kangwon.ac.kr

2013-06-07

Highlights: •Arginase inhibition suppressed proliferation of IL-1β-stimulated VSMCs in dose-dependent manner. •NO production from IL-1β-induced iNOS expression was augmented by arginase inhibition, reducing VSMC proliferation. •Incubation with cGMP analogues abolished IL-1β-dependent proliferation of VSMCs. -- Abstract: We investigated whether arginase inhibition suppressed interleukin (IL)-1β-stimulated proliferation in vascular smooth muscle cells (VSMCs) and the possible mechanisms involved. IL-1β stimulation increased VSMC proliferation, while the arginase inhibitor BEC and transfection of the antisense (AS) oligonucleotide against arginase I decreased VSMC proliferation and was associated with increased protein content of the cell cycle regulator p21Waf1/Cip1. IL-1β incubation induced inducible nitric oxide synthase (iNOS)more » mRNA expression and protein levels in a dose-dependent manner, but did not affect arginase I and II expression. Consistent with this data, IL-1β stimulation resulted in increase in NO production that was significantly augmented by arginase inhibition. The specific iNOS inhibitor 1400W abolished IL-1β-mediated NO production and further accentuated IL-1β-stimulated cell proliferation. Incubation with NO donors GSNO and DETA/NO in the presence of IL-1β abolished VSMCs proliferation and increased p21Waf1/Cip1 protein content. Furthermore, incubation with the cGMP analogue 8-Br-cGMP prevented IL-1β-induced VSMCs proliferation. In conclusion, arginase inhibition augmented iNOS-dependent NO production that resulted in suppression of IL-1β-induced VSMCs proliferation in a cGMP-dependent manner.« less

The calmodulin inhibitor CGS 9343B inhibits voltage-dependent K{sup +} channels in rabbit coronary arterial smooth muscle cells

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

Li, Hongliang; Hong, Da Hye; Kim, Han Sol

We investigated the effects of the calmodulin inhibitor CGS 9343B on voltage-dependent K{sup +} (Kv) channels using whole-cell patch clamp technique in freshly isolated rabbit coronary arterial smooth muscle cells. CGS 9343B inhibited Kv currents in a concentration-dependent manner, with a half-maximal inhibitory concentration (IC{sub 50}) value of 0.81 μM. The decay rate of Kv channel inactivation was accelerated by CGS 9343B. The rate constants of association and dissociation for CGS 9343B were 2.77 ± 0.04 μM{sup −1} s{sup −1} and 2.55 ± 1.50 s{sup −1}, respectively. CGS 9343B did not affect the steady-state activation curve, but shifted the inactivationmore » curve toward to a more negative potential. Train pulses (1 or 2 Hz) application progressively increased the CGS 9343B-induced Kv channel inhibition. In addition, the inactivation recovery time constant was increased in the presence of CGS 9343B, suggesting that CGS 9343B-induced inhibition of Kv channel was use-dependent. Another calmodulin inhibitor, W-13, did not affect Kv currents, and did not change the inhibitory effect of CGS 9343B on Kv current. Our results demonstrated that CGS 9343B inhibited Kv currents in a state-, time-, and use-dependent manner, independent of calmodulin inhibition. - Highlights: • We investigated the effects of CGS 9394B on Kv channels. • CGS 9394B inhibited Kv current in a state-, time-, and use-dependent manner. • Caution is required when using CGS 9394B in vascular function studies.« less

Characterization of the interaction between the heavy and light chains of bovine factor Va.

PubMed

Walker, F J

1992-10-05

Bovine factor Va has been previously been shown to consist of heavy (M(r) = 94,000) and light chains (M(r) = 81,000), that interact in a manner dependent upon the presence of either calcium or manganese ions. In an attempt to understand the mechanism of subunit interaction we have studied the effects of temperature and ions on factor Va stability. The rates of formation of factor Va from isolated chains and dissociation were temperature-dependent with an energy of activation of 6.2 and 1.3 kcal mol-1, respectively. The yield of factor Va from isolated chains was inversely related to the amount of time the chains were incubated at 4 degrees C. Incubation of individual chains revealed that the heavy chain is cold-labile, an effect that is reversible. Manganese ion was observed to prevent the conversion to the inactive form. High salt tends to stabilize the two-chain structure of factor Va, but is inhibitory to its formation from isolated chains. High concentrations of either manganese or calcium ions also inhibited reconstitution of activity. The light chain, in particular, was sensitive to the presence of manganese or calcium ion. Heavy chain that had been cleaved by activated protein C had a weakened interaction with the light chain, and the resulting complex had no procoagulant activity. Cooling of the heavy chain to 4 degrees C enhanced its intrinsic fluorescence. Manganese ion prevented some of this enhancement. The heavy chain fluorescence returned to the room temperature value with a half-life of approximately 10 min. In the presence of manganese ion relaxation was accelerated. The intrinsic fluorescence of activated protein C-cleaved heavy chain was not increased when the temperature was decreased. These data suggest that the heavy chain can exist in two forms. Elevated temperature converts it to a form that can bind ions and have a productive interaction with the light chain. However, conditions that prevent the heavy chain from combining with the light chain also stabilize the two subunit structure, suggesting that the high affinity of the complex is due to conformational changes that occur after chain interaction.

Tangeretin, a citrus polymethoxyflavonoid, induces apoptosis of human gastric cancer AGS cells through extrinsic and intrinsic signaling pathways.

PubMed

Dong, Yang; Cao, Aili; Shi, Jianrong; Yin, Peihao; Wang, Li; Ji, Guang; Xie, Jianqun; Wu, Dazheng

2014-04-01

Tangeretin, a natural polymethoxyflavone present in citrus peel oil, is known to have anticancer activities in breast cancer, colorectal carcinoma and lung carcinoma, yet, the underlying mechanisms of tangeretin in human gastric cancer AGS cells have not been investigated to date. In the present study, the apoptotic mechanisms of tangeretin in AGS cells were explored. It was observed that tangeretin increased the apoptotic rates of AGS cells following treatment with tangeretin for 48 h in a dose-dependent manner by Annexin V-FITC and PI double staining. In addition, characteristic apoptotic morphology such as nuclear shrinkage and apoptotic bodies was observed after Hoechst 33258 staining. Flow cytometric assay showed that treatment of AGS cells with tangeretin decreased the mitochondrial membrane potential (MMP) in a dose-dependent manner, which indicated that mitochondrial dysfunction was involved in the tangeretin-induced apoptosis. Caspase-3, -8 and -9 activities were increased by tangeretin in a dose-dependent manner. Western blotting showed that the protein levels of pro-apoptotic proteins including cleaved caspase-3, cleaved caspase-8, cleaved caspase-9, Bax, Bid, tBid, p53, p21/cip1, Fas and FasL were significantly upregulated by tangeretin. In addition, PFT-α (a p53 inhibitor) reduced the apoptotic rates and the expression of p53, p21, caspase-3 and caspase-9 induced by tangeretin, indicating that tangeretin-induced apoptosis was p53-dependent. In conclusion, these results suggest that tangeretin induces the apoptosis of AGS cells mainly through p53-dependent mitochondrial dysfunction and the Fas/FasL-mediated extrinsic pathway.

Brevicoryne brassicae aphids interfere with transcriptome responses of Arabidopsis thaliana to feeding by Plutella xylostella caterpillars in a density-dependent manner.

PubMed

Kroes, Anneke; Broekgaarden, Colette; Castellanos Uribe, Marcos; May, Sean; van Loon, Joop J A; Dicke, Marcel

2017-01-01

Plants are commonly attacked by multiple herbivorous species. Yet, little is known about transcriptional patterns underlying plant responses to multiple insect attackers feeding simultaneously. Here, we assessed transcriptomic responses of Arabidopsis thaliana plants to simultaneous feeding by Plutella xylostella caterpillars and Brevicoryne brassicae aphids in comparison to plants infested by P. xylostella caterpillars alone, using microarray analysis. We particularly investigated how aphid feeding interferes with the transcriptomic response to P. xylostella caterpillars and whether this interference is dependent on aphid density and time since aphid attack. Various JA-responsive genes were up-regulated in response to feeding by P. xylostella caterpillars. The additional presence of aphids, both at low and high densities, clearly affected the transcriptional plant response to caterpillars. Interestingly, some important modulators of plant defense signalling, including WRKY transcription factor genes and ABA-dependent genes, were differentially induced in response to simultaneous aphid feeding at low or high density compared with responses to P. xylostella caterpillars feeding alone. Furthermore, aphids affected the P. xylostella-induced transcriptomic response in a density-dependent manner, which caused an acceleration in plant response against dual insect attack at high aphid density compared to dual insect attack at low aphid density. In conclusion, our study provides evidence that aphids influence the caterpillar-induced transcriptional response of A. thaliana in a density-dependent manner. It highlights the importance of addressing insect density to understand how plant responses to single attackers interfere with responses to other attackers and thus underlines the importance of the dynamics of transcriptional plant responses to multiple herbivory.

Parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner.

PubMed

Otani, Koichi; Suzuki, Akihito; Matsumoto, Yoshihiko; Shibuya, Naoshi; Sadahiro, Ryoichi; Enokido, Masanori

2013-12-24

It has been suggested that dysfunctional attitudes, cognitive vulnerability to depression, have developmental origins. The present study examined the effects of parental rearing on dysfunctional attitudes in three areas of life with special attention to gender specificity. The subjects were 665 Japanese healthy volunteers. Dysfunctional attitudes were assessed by the 24-item Dysfunctional Attitude Scale, which has the Achievement, Dependency and Self-control subscales. Perceived parental rearing was assessed by the Parental Bonding Instrument, which has the Care and Protection subscales. Higher scores of the Achievement (β = 0.293, p < 0.01) and Dependency (β = 0.224, p < 0.05) subscales were correlated with higher scores of the Protection subscale in the combination of mother and daughter, but not in other combinations of parents and recipients. Scores of the Self-control subscale were not correlated with paternal or maternal rearing scores. The present study suggests that parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner.

Thermally Tunable Hydrogels Displaying Angle-Independent Structural Colors.

PubMed

Ohtsuka, Yumiko; Seki, Takahiro; Takeoka, Yukikazu

2015-12-14

We report the preparation of thermally tunable hydrogels displaying angle-independent structural colors. The porous structures were formed with short-range order using colloidal amorphous array templates and a small amount of carbon black (CB). The resultant porous hydrogels prepared using colloidal amorphous arrays without CB appeared white, whereas the hydrogels with CB revealed bright structural colors. The brightly colored hydrogels rapidly changed hues in a reversible manner, and the hues varied widely depending on the water temperature. Moreover, the structural colors were angle-independent under diffusive lighting because of the isotropic nanostructure generated from the colloidal amorphous arrays. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

The Effects of Orbital Spaceflight on Human Osteoblastic Cell Physiology and Gene Expression

NASA Technical Reports Server (NTRS)

Turner, R. T.

1999-01-01

The purpose of the proposed study is to establish whether changes in gravitational loading have a direct effect on osteoblasts to regulate TGF-6 expression. The effects of spaceflight and reloading on TGF-B MRNA and peptide levels will be studied in a newly developed line of immortalized human fetal osteoblasts (HFOB) transfected with an SV-40 temperature dependent mutant to generate proliferating, undifferentiated hFOB cells at 33-34 C and a non-proliferating, differentiated HFOB cells at 37-39'C. Unlike previous cell culture models, HFOB cells have unlimited proliferative capacity yet can be precisely regulated to differentiate into mature cells which express mature osteoblast function. If isolated osteoblasts respond to changes in mechanical loading in a manner similar to their response in animals, the cell system could provide a powerful model to investigate the signal transduction pathway for gravitational loading.

The Ionotropic Receptors IR21a and IR25a mediate cool sensing in Drosophila.

PubMed

Ni, Lina; Klein, Mason; Svec, Kathryn V; Budelli, Gonzalo; Chang, Elaine C; Ferrer, Anggie J; Benton, Richard; Samuel, Aravinthan Dt; Garrity, Paul A

2016-04-29

Animals rely on highly sensitive thermoreceptors to seek out optimal temperatures, but the molecular mechanisms of thermosensing are not well understood. The Dorsal Organ Cool Cells (DOCCs) of the Drosophila larva are a set of exceptionally thermosensitive neurons critical for larval cool avoidance. Here, we show that DOCC cool-sensing is mediated by Ionotropic Receptors (IRs), a family of sensory receptors widely studied in invertebrate chemical sensing. We find that two IRs, IR21a and IR25a, are required to mediate DOCC responses to cooling and are required for cool avoidance behavior. Furthermore, we find that ectopic expression of IR21a can confer cool-responsiveness in an Ir25a-dependent manner, suggesting an instructive role for IR21a in thermosensing. Together, these data show that IR family receptors can function together to mediate thermosensation of exquisite sensitivity.

Finite Element Modeling and Analysis of Powder Stream in Low Pressure Cold Spray Process

NASA Astrophysics Data System (ADS)

Goyal, Tarun; Walia, Ravinderjit Singh; Sharma, Prince; Sidhu, Tejinder Singh

2016-07-01

Low pressure cold gas dynamic spray (LPCGDS) is a coating process that utilize low pressure gas (5-10 bars instead of 25-30 bars) and the radial injection of powder instead of axial injection with the particle range (1-50 μm). In the LPCGDS process, pressurized compressed gas is accelerated to the critical velocity, which depends on length of the divergent section of nozzle, the propellant gas and particle characteristics, and the diameters ratio of the inlet and outer diameters. This paper presents finite element modeling (FEM) of powder stream in supersonic nozzle wherein adiabatic gas flow and expansion of gas occurs in uniform manner and the same is used to evaluate the resultant temperature and velocity contours during coating process. FEM analyses were performed using commercial finite volume package, ANSYS CFD FLUENT. The results are helpful to predict the characteristics of powder stream at the exit of the supersonic nozzle.

Pathway-engineering for highly-aligned block copolymer arrays.

PubMed

Choo, Youngwoo; Majewski, Paweł W; Fukuto, Masafumi; Osuji, Chinedum O; Yager, Kevin G

2017-12-21

While the ultimate driving force in self-assembly is energy minimization and the corresponding evolution towards equilibrium, kinetic effects can also play a very strong role. These kinetic effects, such as trapping in metastable states, slow coarsening kinetics, and pathway-dependent assembly, are often viewed as complications to be overcome. Here, we instead exploit these effects to engineer a desired final nano-structure in a block copolymer thin film, by selecting a particular ordering pathway through the self-assembly energy landscape. In particular, we combine photothermal shearing with high-temperature annealing to yield hexagonal arrays of block copolymer cylinders that are aligned in a single prescribed direction over macroscopic sample dimensions. Photothermal shearing is first used to generate a highly-aligned horizontal cylinder state, with subsequent thermal processing used to reorient the morphology to the vertical cylinder state in a templated manner. Finally, we demonstrate the successful transfer of engineered morphologies into inorganic replicas.

Diagnosing the Internal Architecture of Zeolite Ferrierite

PubMed Central

Schmidt, Joel E.; Hendriks, Frank C.; Lutz, Martin; Post, L. Christiaan; Fu, Donglong

2017-01-01

Abstract Large crystals of zeolite ferrierite (FER) are important model systems for spatially resolved catalysis and diffusion studies, though there is considerable variation in crystal habit depending on the chemical composition and employed synthesis conditions. A synergistic combination of techniques has been applied, including single crystal X‐ray diffraction, high‐temperature in situ confocal fluorescence microscopy, fluorescent probe molecules, wide‐field microscopy and atomic force microscopy to unravel the internal architecture of three distinct FER zeolites. Pyrolyzed template species can be used as markers for the 8‐membered ring direction as they are trapped in the terraced roof of the FER crystals. This happens as the materials grow in a layer‐by‐layer, defect‐free manner normal to the large crystal surface, and leads to a facile method to diagnose the pore system orientation, which avoids tedious single crystal X‐ray diffraction experiments. PMID:28809081

Partial purification and characterization of cysteine proteinase inhibitor from chicken plasma.

PubMed

Rawdkuen, Saroat; Benjakul, Soottawat; Visessanguan, Wonnop; Lanier, Tyre C

2006-08-01

A high-molecular-weight cysteine proteinase inhibitor (CPI) was purified from chicken (Gallus gallus) plasma using polyethylene glycol (PEG) fractionation and affinity chromatography on carboxymethyl-papain-Sepharose-4B. The CPI was purified 96.8-fold with a yield of 28.9%. Based on inhibitory activity staining for papain, CPI was shown to have an apparent molecular mass of 122 kDa. No inhibitory activity was obtained under reducing condition, indicating that CPI from chicken plasma was stabilized by disulfide bonds. CPI was stable in temperature ranges from 40 to 70 degrees C for 10 min; however, more than 50% of the inhibitory activity towards papain was lost within 30 min of heating at 90 degrees C. CPI was stable in the presence of salt up to 3%. The purified CPI exhibited the inhibitory activity toward autolysis of arrowtooth flounder (Atheresthes stomias) and Pacific whiting (Merluccius productus) natural actomyosin (NAM) in a concentration-dependent manner.

Disinfection potential of electrolyzed solutions containing sodium chloride at low concentrations.

PubMed

Morita, C; Sano, K; Morimatsu, S; Kiura, H; Goto, T; Kohno, T; Hong, W U; Miyoshi, H; Iwasawa, A; Nakamura, Y; Tagawa, M; Yokosuka, O; Saisho, H; Maeda, T; Katsuoka, Y

2000-03-01

Electrolyzed products of sodium chloride solution were examined for their disinfection potential against hepatitis B virus (HBV) and human immunodeficiency virus (HIV) in vitro. Electrolysis of 0.05% NaCl in tap water was carried out for 45 min at room temperature using a 3 A electric current in separate wells installed with positive and negative electrodes. The electrolyzed products were obtained from the positive well. The oxidation reduction potential (ORP), pH and free chlorine content of the product were 1053 mV, pH 2.34 and 4.20 ppm, respectively. The products modified the antigenicity of the surface protein of HBV as well as the infectivity of HIV in time- and concentration-dependent manner. Although the inactivating potential was decreased by the addition of contaminating protein, recycling of the product or continuous addition of fresh product may restore the complete disinfection against bloodborne pathogens.

Optimizing Host-Pathogen In-Flight Assays for C.Elegans and Methicillin-Resistant Staphylococcus Aureus

NASA Astrophysics Data System (ADS)

Hammond, Timothy G.; Birdsall, Holly H.; Hammond, Jeffrey S.; Allen, Patricia L.

2013-02-01

This study addresses controls for an assay of bacterial virulence that has been optimized for space flight studies. Caenorhabditis elegans (C. elegans) worms ingest microorganisms, but are also killed by virulent bacteria. Virulence is assessed by the number of bacteria surviving in co-culture with C. elegans , as measured by optical density at 620 nm. Co -cultures of Methicillin-resistant Staphylococcus aureus (MRSA) with C. elegans have a higher OD620 than MRSA grown alone, which could reflect debris from dead worms and/or enhanced growth of the MRSA in response to worm-derived factors. The use of media conditioned by pre-incubation with worms demonstrated the presence of temperature-stable factors that change MRSA growth in a strain-dependent manner. Some sources of deionized water contain an undefined antibacterial activity present in conditioned, but not fresh untreated media.

A Coarse-Grained Protein Model in a Water-like Solvent

NASA Astrophysics Data System (ADS)

Sharma, Sumit; Kumar, Sanat K.; Buldyrev, Sergey V.; Debenedetti, Pablo G.; Rossky, Peter J.; Stanley, H. Eugene

2013-05-01

Simulations employing an explicit atom description of proteins in solvent can be computationally expensive. On the other hand, coarse-grained protein models in implicit solvent miss essential features of the hydrophobic effect, especially its temperature dependence, and have limited ability to capture the kinetics of protein folding. We propose a free space two-letter protein (``H-P'') model in a simple, but qualitatively accurate description for water, the Jagla model, which coarse-grains water into an isotropically interacting sphere. Using Monte Carlo simulations, we design protein-like sequences that can undergo a collapse, exposing the ``Jagla-philic'' monomers to the solvent, while maintaining a ``hydrophobic'' core. This protein-like model manifests heat and cold denaturation in a manner that is reminiscent of proteins. While this protein-like model lacks the details that would introduce secondary structure formation, we believe that these ideas represent a first step in developing a useful, but computationally expedient, means of modeling proteins.

Evaluation of the effects of a plasma activated medium on cancer cells

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

Mohades, S.; Laroussi, M., E-mail: mlarouss@odu.edu; Sears, J.

2015-12-15

The interaction of low temperature plasma with liquids is a relevant topic of study to the field of plasma medicine. This is because cells and tissues are normally surrounded or covered by biological fluids. Therefore, the chemistry induced by the plasma in the aqueous state becomes crucial and usually dictates the biological outcomes. This process became even more important after the discovery that plasma activated media can be useful in killing various cancer cell lines. Here, we report on the measurements of concentrations of hydrogen peroxide, a species known to have strong biological effects, produced by application of plasma tomore » a minimum essential culture medium. The activated medium is then used to treat SCaBER cancer cells. Results indicate that the plasma activated medium can kill the cancer cells in a dose dependent manner, retain its killing effect for several hours, and is as effective as apoptosis inducing drugs.« less

Glycation of β-lactoglobulin and antiglycation by genistein in different reactive carbonyl model systems.

PubMed

Kong, Yanghui; Li, Xiaoming; Zheng, Tiesong; Lv, Lishuang

2015-09-15

Advanced glycation end products (AGEs), which are formed in β-lactoglobulin (β-lg) glycation systems via the Maillard reaction, have been implicated in diabetes-related long-term complications. In the present study, we found that reaction conditions, including temperature, time, pH, reactant type and molar ratio of beta-lg to a sugar/MGO/GO, can significantly affect the formation of AGEs. Using SDS-PAGE, we further demonstrated that genistein, a natural isoflavone found in a number of plants including soybeans and kudzu, can efficiently inhibit cross-links of the glycated β-lg, and suppress the formation AGEs in a dose-dependent manner by trapping reactive dicarbonyl compounds. The products formed from genistein and methylglyoxal (MGO) in the β-lg-MGO assay were analyzed using LC/MS. Both mono-MGO and di-MGO adducts of genistein were detected with this method. Copyright © 2015 Elsevier Ltd. All rights reserved.

Kinetics and evolved gas analysis for pyrolysis of food processing wastes using TGA/MS/FT-IR.

PubMed

Özsin, Gamzenur; Pütün, Ayşe Eren

2017-06-01

The objective of this study was to identify the pyrolysis of different bio-waste produced by food processing industry in a comprehensible manner. For this purpose, pyrolysis behaviors of chestnut shells (CNS), cherry stones (CS) and grape seeds (GS) were investigated by thermogravimetric analysis (TGA) combined with a Fourier-transform infrared (FT-IR) spectrometer and a mass spectrometer (MS). In order to make available theoretical groundwork for biomass pyrolysis, activation energies were calculated with the help of four different model-free kinetic methods. The results are attributed to the complex reaction schemes which imply parallel, competitive and complex reactions during pyrolysis. During pyrolysis, the evolution of volatiles was also characterized by FT-IR and MS. The main evolved gases were determined as H 2 O, CO 2 and hydrocarbons such as CH 4 and temperature dependent profiles of the species were obtained. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inactivation of Clostridium difficile spores by microwave irradiation.

PubMed

Ojha, Suvash Chandra; Chankhamhaengdecha, Surang; Singhakaew, Sombat; Ounjai, Puey; Janvilisri, Tavan

2016-04-01

Spores are a potent agent for Clostridium difficile transmission. Therefore, factors inhibiting spores have been of continued interest. In the present study, we investigated the influence of microwave irradiation in addition to conductive heating for C. difficile spore inactivation in aqueous suspension. The spores of 15 C. difficile isolates from different host origins were exposed to conductive heating and microwave irradiation. The complete inhibition of spore viability at 10(7) CFU/ml was encountered following microwave treatment at 800 W for 60 s, but was not observed in the conductive-heated spores at the same time-temperature exposure. The distinct patterns of ultrastructural alterations following microwave and conductive heat treatment were observed and the degree of damages by microwave was in the exposure time-dependent manner. Microwave would therefore be a simple and time-efficient tool to inactivate C. difficile spores, thus reducing the risk of C. difficile transmission. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electronic spin transport in gate-tunable black phosphorus spin valves

NASA Astrophysics Data System (ADS)

Liu, Jiawei; Avsar, Ahmet; Tan, Jun You; Oezyilmaz, Barbaros

High charge mobility, the electric field effect and small spin-orbit coupling make semiconducting black phosphorus (BP) a promising material for spintronics device applications requiring long spin distance spin communication with all rectification and amplification actions. Towards this, we study the all electrical spin injection, transport and detection under non-local spin valve geometry in fully encapsulated ultra-thin BP devices. We observe spin relaxation times as high as 4 ns, with spin relaxation lengths exceeding 6 μm. These values are an order of magnitude higher than what have been measured in typical graphene spin valve devices. Moreover, the spin transport depends strongly on charge carrier concentration and can be manipulated in a spin transistor-like manner by controlling electric field. This behaviour persists even at room temperature. Finally, we will show that similar to its electrical and optical properties, spin transport property is also strongly anisotropic.

Oxygen consumption and body temperature of active and resting honeybees.

PubMed

Stabentheiner, Auton; Vollmann, Jutta; Kovac, Helmut; Crailsheim, Karl

2003-09-01

We measured the energy turnover (oxygen consumption) of honeybees (Apis mellifera carnica), which were free to move within Warburg vessels. Oxygen consumption of active bees varied widely depending on ambient temperature and level of activity, but did not differ between foragers (>18 d) and middle-aged hive bees (7-10 d). In highly active bees, which were in an endothermic state ready for flight, it decreased almost linearly, from a maximum of 131.4 microl O(2) min(-1) at 15 degrees C ambient temperature to 81.1 microl min(-1) at 25 degrees C, and reached a minimum of 29.9 microl min(-1) at 40 degrees C. In bees with low activity, it decreased from 89.3 microl O(2) min(-1) at 15 degrees C to 47.9 microl min(-1) at 25 degrees C and 14.7 microl min(-1) at 40 degrees C. Thermographic measurements of body temperature showed that with increasing activity, the bees invested more energy to regulate the thorax temperature at increasingly higher levels (38.8-41.2 degrees C in highly active bees) and were more accurate. Resting metabolism was determined in young bees of 1-7 h age, which are not yet capable of endothermic heat production with their flight muscles. Their energy turnover increased from 0.21 microl O(2) min(-1) at 10 degrees C to 0.38 microl min(-1) at 15 degrees C, 1.12 microl min(-1) at 25 degrees C, and 3.03 microl min(-1) at 40 degrees C. At 15, 25 and 40 degrees C, this was 343, 73 and 10 times below the values of the highly active bees, respectively. The Q(10) value of the resting bees, however, was not constant but varied in a U-shaped manner with ambient temperature. It decreased from 4.24 in the temperature range 11-21 degrees C to 1.35 in the range 21-31 degrees C, and increased again to 2.49 in the range 30-40 degrees C. We conclude that attempts to describe the temperature dependence of the resting metabolism of honeybees by Q(10) values can lead to considerable errors if the measurements are performed at only two temperatures. An acceptable approximation can be derived by calculation of an interpolated Q(10) according to the exponential function (V(O(2))=0.151 x 1.0784(T(a))) (interpolated Q(10)=2.12).

Metabolic efficiency in yeast Saccharomyces cerevisiae in relation to temperature dependent growth and biomass yield.

PubMed

Zakhartsev, Maksim; Yang, Xuelian; Reuss, Matthias; Pörtner, Hans Otto

2015-08-01

Canonized view on temperature effects on growth rate of microorganisms is based on assumption of protein denaturation, which is not confirmed experimentally so far. We develop an alternative concept, which is based on view that limits of thermal tolerance are based on imbalance of cellular energy allocation. Therefore, we investigated growth suppression of yeast Saccharomyces cerevisiae in the supraoptimal temperature range (30-40°C), i.e. above optimal temperature (Topt). The maximal specific growth rate (μmax) of biomass, its concentration and yield on glucose (Yx/glc) were measured across the whole thermal window (5-40°C) of the yeast in batch anaerobic growth on glucose. Specific rate of glucose consumption, specific rate of glucose consumption for maintenance (mglc), true biomass yield on glucose (Yx/glc(true)), fractional conservation of substrate carbon in product and ATP yield on glucose (Yatp/glc) were estimated from the experimental data. There was a negative linear relationship between ATP, ADP and AMP concentrations and specific growth rate at any growth conditions, whilst the energy charge was always high (~0.83). There were two temperature regions where mglc differed 12-fold, which points to the existence of a 'low' (within 5-31°C) and a 'high' (within 33-40°C) metabolic mode regarding maintenance requirements. The rise from the low to high mode occurred at 31-32°C in step-wise manner and it was accompanied with onset of suppression of μmax. High mglc at supraoptimal temperatures indicates a significant reduction of scope for growth, due to high maintenance cost. Analysis of temperature dependencies of product formation efficiency and Yatp/glc revealed that the efficiency of energy metabolism approaches its lower limit at 26-31°C. This limit is reflected in the predetermined combination of Yx/glc(true), elemental biomass composition and degree of reduction of the growth substrate. Approaching the limit implies a reduction of the safety margin of metabolic efficiency. We hypothesize that a temperature increase above Topt (e.g. >31°C) triggers both an increment in mglc and suppression of μmax, which together contribute to an upshift of Yatp/glc from the lower limit and thus compensate for the loss of the safety margin. This trade-off allows adding 10 more degrees to Topt and extends the thermal window up to 40°C, sustaining survival and reproduction in supraoptimal temperatures. Deeper understanding of the limits of thermal tolerance can be practically exploited in biotechnological applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

New Gravity Wave Treatments for GISS Climate Models

NASA Technical Reports Server (NTRS)

Geller, Marvin A.; Zhou, Tiehan; Ruedy, Reto; Aleinov, Igor; Nazarenko, Larissa; Tausnev, Nikolai L.; Sun, Shan; Kelley, Maxwell; Cheng, Ye

2011-01-01

Previous versions of GISS climate models have either used formulations of Rayleigh drag to represent unresolved gravity wave interactions with the model-resolved flow or have included a rather complicated treatment of unresolved gravity waves that, while being climate interactive, involved the specification of a relatively large number of parameters that were not well constrained by observations and also was computationally very expensive. Here, the authors introduce a relatively simple and computationally efficient specification of unresolved orographic and nonorographic gravity waves and their interaction with the resolved flow. Comparisons of the GISS model winds and temperatures with no gravity wave parameterization; with only orographic gravity wave parameterization; and with both orographic and nonorographic gravity wave parameterizations are shown to illustrate how the zonal mean winds and temperatures converge toward observations. The authors also show that the specifications of orographic and nonorographic gravity waves must be different in the Northern and Southern Hemispheres. Then results are presented where the nonorographic gravity wave sources are specified to represent sources from convection in the intertropical convergence zone and spontaneous emission from jet imbalances. Finally, a strategy to include these effects in a climate-dependent manner is suggested.

Graphene and temperature controlled butterfly shape in permittivity-field loops of ferroelectric polymer nanocomposites

NASA Astrophysics Data System (ADS)

Adohi, B. J. P.; Brosseau, C.; Laur, V.; Haidar, B.

2017-01-01

We report on the field-dependent polarization of graphene (GE) filled poly[vinylidene fluoride-co-trifluoroethylene] P(VDF-TrFE) nanostructures fabricated by mechanical melt mixing. This study shows an increase in effective permittivity of these nanomaterials on increasing the GE loading in a manner that is consistent with standard mixing law. Detailed characterization of the unsaturated ferroelectric hysteresis, as well as the butterfly shape of the effective permittivity versus electric bias, of the samples are presented. For GE content set to 9.1 wt. % in the samples containing 50/50 wt. % (VDF/TrFE), the maximum polarization increases by 260% with respect to that of the neat polymer matrix. With a higher VDF content, 73 wt. %, the coercive field remains constant over the range of GE content explored. Additionally, our results highlight the strong impact of the GE loading and temperature on the butterfly shape in permittivity-field loops of these nanocomposites. The experimental findings are consistent with theoretical predictions of the modified Johnson's model [Narayanan et al., Appl. Phys. Lett. 100, 022907 (2012)]. Our findings can open avenues for interplay between conductive nanofillers and ferroelectricity in soft nanomaterials with controlled phase transitions.

Role of the Charge-Transfer State in Reduced Langevin Recombination in Organic Solar Cells: A Theoretical Study

PubMed Central

2015-01-01

Reduced Langevin recombination has been observed in organic solar cells (OSCs) for many years, but its origin is still unclear. A recent work by Burke et al. (Adv. Energy Mater.2015, 5, 1500123-1) was inspired by this reduced Langevin recombination, and they proposed an equilibrium model of charge-transfer (CT) states that correlates the open-circuit voltage of OSCs with experimentally available device parameters. In this work, we extend Burke et al.’s CT model further and for the first time directly correlate the reduced Langevin recombination with the energetic and dynamic behavior of the CT state. Recombination through CT states leads in a straightforward manner to a decrease in the Langevin reduction factor with increasing temperature, without explicit consideration of the temperature dependence of the mobility. To verify the correlation between the CT states and reduced Langevin recombination, we incorporated this CT model and the reduced Langevin model into drift-diffusion simulations of a bilayer OSC. The simulations not only successfully reproduced realistic current–voltage (J–V) characteristics of the bilayer OSC, but also demonstrate that the two models consistently lead to same value of the apparent Langevin reduction factor. PMID:26640611

In situ investigation of explosive crystallization in a-Ge: Experimental determination of the interface response function using dynamic transmission electron microscopy

NASA Astrophysics Data System (ADS)

Nikolova, Liliya; Stern, Mark J.; MacLeod, Jennifer M.; Reed, Bryan W.; Ibrahim, Heide; Campbell, Geoffrey H.; Rosei, Federico; LaGrange, Thomas; Siwick, Bradley J.

2014-09-01

The crystallization of amorphous semiconductors is a strongly exothermic process. Once initiated the release of latent heat can be sufficient to drive a self-sustaining crystallization front through the material in a manner that has been described as explosive. Here, we perform a quantitative in situ study of explosive crystallization in amorphous germanium using dynamic transmission electron microscopy. Direct observations of the speed of the explosive crystallization front as it evolves along a laser-imprinted temperature gradient are used to experimentally determine the complete interface response function (i.e., the temperature-dependent front propagation speed) for this process, which reaches a peak of 16 m/s. Fitting to the Frenkel-Wilson kinetic law demonstrates that the diffusivity of the material locally/immediately in advance of the explosive crystallization front is inconsistent with those of a liquid phase. This result suggests a modification to the liquid-mediated mechanism commonly used to describe this process that replaces the phase change at the leading amorphous-liquid interface with a change in bonding character (from covalent to metallic) occurring in the hot amorphous material.

An analysis of laminar free-convection flow and heat transfer about a flat plate paralled to the direction of the generating body force

NASA Technical Reports Server (NTRS)

Ostrach, Simon

1953-01-01

The free-convection flow and heat transfer (generated by a body force) about a flat plate parallel to the direction of the body force are formally analyzed and the type of flow is found to be dependent on the Grashof number alone. For large Grashof numbers (which are of interest in aeronautics), the flow is of the boundary-layer type and the problem is reduced in a formal manner, which is analogous to Prandtl's forced-flow boundary-layer theory, to the simultaneous solution of two ordinary differential equations subject to the proper boundary conditions. Velocity and temperature distributions for Prandtl numbers of 0.01, 0.72, 0.733, 1, 1, 10, 100, and 1000 are computed, and it is shown that velocities and Nusselt numbers of the order of magnitude of those encountered in forced-convection flows may be obtained in free-convection flows. The theoretical and experimental velocity and temperature distributions are in good agreement. A flow and a heat-transfer parameter, from which the important physical quantities such as shear stress and heat-transfer rate can be computed, are derived as functions of Prandtl number alone.

Physical properties of YBa 2Cu 3O 7- δ thin films using microstrip ring resonators technique

NASA Astrophysics Data System (ADS)

Lai, L. S.; Zeng, H. K.; Juang, J. Y.; Wu, K. H.; Uen, T. M.; Lin, J. Y.; Gou, Y. S.

2006-09-01

Microstrip ring resonators with quality factor ( Q) over 10 4 at temperature 5 K, were fabricated using the double-side YBa 2Cu 3O 7- δ (YBCO) epitaxial films deposited on LaAlO 3 (LAO) substrates. By placing a narrow gap in the ring resonator, we observed that the original fundamental resonating mode (resonance frequency f = 3.61 GHz) splits into a dual-mode with different resonating frequencies ( f = 1.80 GHz and f = 5.33 GHz). These two kinds of the resonator allow us to determine the temperature and frequency dependences of the magnetic penetration depth λ( T, f) and the surface loss. Several salient features of the above findings related to the nature of low-lying excitations for high- Tc superconductivity as a function of oxygen content will be elucidated. In particular, the current models, suggested by Wen and Lee, will be examined in a quantitative manner. It allows us to give a justification of quasiparticle as Fermi-liquid in the superconducting state. In addition, an equivalent inductance circuit model is suggested to account for the occurrence of the dual-mode resonance.

New Gravity Wave Treatments for GISS Climate Models

NASA Technical Reports Server (NTRS)

Geller, Marvin A.; Zhou, Tiehan; Ruedy, Reto; Aleinov, Igor; Nazarenko, Larissa; Tausnev, Nikolai L.; Sun, Shan; Kelley, Maxwell; Cheng, Ye

2010-01-01

Previous versions of GISS climate models have either used formulations of Rayleigh drag to represent unresolved gravity wave interactions with the model resolved flow or have included a rather complicated treatment of unresolved gravity waves that, while being climate interactive, involved the specification of a relatively large number of parameters that were not well constrained by observations and also was computationally very expensive. Here, we introduce a relatively simple and computationally efficient specification of unresolved orographic and non-orographic gravity waves and their interaction with the resolved flow. We show comparisons of the GISS model winds and temperatures with no gravity wave parametrization; with only orographic gravity wave parameterization; and with both orographic and non-orographic gravity wave parameterizations to illustrate how the zonal mean winds and temperatures converge toward observations. We also show that the specifications of orographic and nonorographic gravity waves must be different in the Northern and Southern Hemispheres. We then show results where the non-orographic gravity wave sources are specified to represent sources from convection in the Intertropical Convergence Zone and spontaneous emission from jet imbalances. Finally, we suggest a strategy to include these effects in a climate dependent manner.

LipL53, a temperature regulated protein from Leptospira interrogans that binds to extracellular matrix molecules.

PubMed

Oliveira, Tatiane R; Longhi, Mariana T; Gonçales, Amane P; de Morais, Zenaide M; Vasconcellos, Silvio A; Nascimento, Ana L T O

2010-03-01

The regulation of gene expression by environmental signals, such as temperature and osmolarity, has been correlated with virulence. In this study, we characterize the protein LipL53 from Leptospira interrogans, previously shown to react with serum sample of individual diagnosed with leptospirosis and to be up-regulated by shift to physiological osmolarity. The recombinant protein was expressed in Escherichia coli system, in insoluble form, recovered by urea solubilization and further refolded by decreasing the denaturing agent concentration during the purification procedure. The secondary structure content of the recombinant LipL53, as assessed by circular dichroism, showed a mixture of beta-strands and alpha-helix. The presence of LipL53 transcript at 28 degrees C was only detected within the virulent strains. However, upon shifted of attenuated cultures of pathogenic strains from 28 degrees C to 37 degrees C and to 39 degrees C, this transcript could also be observed. LipL53 binds laminin, collagen IV, cellular and plasma fibronectin in dose-dependent and saturable manner. Animal challenge studies showed that LipL53, although immunogenic, elicited only partial protection in hamsters. LipL53 is probably surface exposed as seen through immunofluorescence confocal microscopy. Our results suggest that LipL53 is a novel temperature regulated adhesin of L. interrogans that may be relevant in the leptospiral pathogenesis. Copyright 2009 Elsevier Masson SAS. All rights reserved.

Self-consistent phonons revisited. I. The role of thermal versus quantum fluctuations on structural transitions in large Lennard-Jones clusters.

PubMed

Georgescu, Ionuţ; Mandelshtam, Vladimir A

2012-10-14

The theory of self-consistent phonons (SCP) was originally developed to address the anharmonic effects in condensed matter systems. The method seeks a harmonic, temperature-dependent Hamiltonian that provides the "best fit" for the physical Hamiltonian, the "best fit" being defined as the one that optimizes the Helmholtz free energy at a fixed temperature. The present developments provide a scalable O(N) unified framework that accounts for anharmonic effects in a many-body system, when it is probed by either thermal (ℏ → 0) or quantum fluctuations (T → 0). In these important limits, the solution of the nonlinear SCP equations can be reached in a manner that requires only the multiplication of 3N × 3N matrices, with no need of diagonalization. For short range potentials, such as Lennard-Jones, the Hessian, and other related matrices are highly sparse, so that the scaling of the matrix multiplications can be reduced from O(N(3)) to ~O(N). We investigate the role of quantum effects by continuously varying the de-Boer quantum delocalization parameter Λ and report the N-Λ (T = 0), and also the classical N-T (Λ = 0) phase diagrams for sizes up to N ~ 10(4). Our results demonstrate that the harmonic approximation becomes inadequate already for such weakly quantum systems as neon clusters, or for classical systems much below the melting temperatures.

The behavioral energetics of New Zealand's bats: Daily torpor and hibernation, a continuum.

PubMed

McNab, Brian K; O'Donnell, Colin

2018-05-07

We examine the impact of behavior on the short-term energy expenditures of the only terrestrial mammals endemic to New Zealand, two bats, the long-tailed (Chalinolobus tuberculatus, family Vespertilionidae), and the lesser short-tailed (Mystacina tuberculata, family Mystacinidae). Vespertilionidae has a world-wide distribution. Mystacinidae is restricted to New Zealand, although related to five neotropical families and one in Madagascar reflecting a shared Gondwanan origin of their Noctilionoidea superfamily. Both species have highly variable body temperatures and rates of metabolism. They feed on flying insects, which requires them to be torpid in shelters during cold, wet periods. In dry weather Mystacina is active in winter at ambient temperatures as low as -1.0 °C, foraging for terrestrial invertebrates in leaf litter, even in the presence of snow, and consuming fruit, nectar, and pollen from endemic plants that bloom in winter. The behavior of Mystacina expands its presence in a cool, wet, temperate forest in a manner unlike any other bat, another example of the distinctive characteristics of the endemic New Zealand fauna. The use of torpor generally depends on a series of factors, including body mass, ambient temperature, latitude, reproductive cycle, sociality, and fat deposits. These factors result in a diversity of responses that range along a continuum from short-term torpor to hibernation. Copyright © 2018. Published by Elsevier Inc.

Temperature and Light modulate the trans-delta3-hexadecenoic acid content of phosphatidylglycerol: light-harvesting complex II organization and non-photochemical quenching.

PubMed

Gray, Gordon R; Ivanov, Alexander G; Król, Marianna; Williams, John P; Kahn, Mobashoher U; Myscich, Elizabeth G; Huner, Norman P A

2005-08-01

The interaction of light and temperature in the modulation of the trans-delta3-hexadecenoic acid (trans-16:1) content of phosphatidylglycerol (PG) in winter rye (Secale cereale L.) was assessed and related to the organization of light-harvesting complex II (LHCII). Increasing the growth irradiance from 50 to 800 micromol m(-2) s(-1) at 20 degrees C resulted in a 1.8-fold increase in the trans-16:1 content in PG which favoured a greater preponderance of oligomeric LHCII, measured in vitro as the ratio of oligomer : monomer. Similar irradiance-dependent increases were observed during growth at 5 degrees C; however, 1.4-fold lower trans-16:1 contents and lower LHCII oligomer : monomer ratios were observed compared with growth at 20 degrees C and the same irradiance. These trends were also observed under natural field conditions. Thus, the accumulation of trans-16:1, as well as the organization of LHCII are modulated by both growth irradiance and growth temperature in an independent but additive manner. We also examined how changes in the supramolecular organization of LHCII affected the capacity for non-photochemical quenching (q(N)) and photoprotection via antenna quenching (q(O)). While q(O) was positively correlated with q(N), there was no correlation with either LHCII organization or xanthophyll cycle activity under the steady-state growth conditions examined.

A Unique cis-Encoded Small Noncoding RNA Is Regulating Legionella pneumophila Hfq Expression in a Life Cycle-Dependent Manner.

PubMed

Oliva, Giulia; Sahr, Tobias; Rolando, Monica; Knoth, Maike; Buchrieser, Carmen

2017-01-10

Legionella pneumophila is an environmental bacterium that parasitizes protozoa, but it may also infect humans, thereby causing a severe pneumonia called Legionnaires' disease. To cycle between the environment and a eukaryotic host, L. pneumophila is regulating the expression of virulence factors in a life cycle-dependent manner: replicating bacteria do not express virulence factors, whereas transmissive bacteria are highly motile and infective. Here we show that Hfq is an important regulator in this network. Hfq is highly expressed in transmissive bacteria but is expressed at very low levels in replicating bacteria. A L. pneumophila hfq deletion mutant exhibits reduced abilities to infect and multiply in Acanthamoeba castellanii at environmental temperatures. The life cycle-dependent regulation of Hfq expression depends on a unique cis-encoded small RNA named Anti-hfq that is transcribed antisense of the hfq transcript and overlaps its 5' untranslated region. The Anti-hfq sRNA is highly expressed only in replicating L. pneumophila where it regulates hfq expression through binding to the complementary regions of the hfq transcripts. This results in reduced Hfq protein levels in exponentially growing cells. Both the small noncoding RNA (sRNA) and hfq mRNA are bound and stabilized by the Hfq protein, likely leading to the cleavage of the RNA duplex by the endoribonuclease RNase III. In contrast, after the switch to transmissive bacteria, the sRNA is not expressed, allowing now an efficient expression of the hfq gene and consequently Hfq. Our results place Hfq and its newly identified sRNA anti-hfq in the center of the regulatory network governing L. pneumophila differentiation from nonvirulent to virulent bacteria. The abilities of L. pneumophila to replicate intracellularly and to cause disease depend on its capacity to adapt to different extra- and intracellular environmental conditions. Therefore, a timely and fine-tuned expression of virulence factors and adaptation traits is crucial. Yet, the regulatory circuits governing the life cycle of L. pneumophila from replicating to virulent bacteria are only partly uncovered. Here we show that the life cycle-dependent regulation of the RNA chaperone Hfq relies on a small regulatory RNA encoded antisense to the hfq-encoding gene through a base pairing mechanism. Furthermore, Hfq regulates its own expression in an autoregulatory loop. The discovery of this RNA regulatory mechanism in L. pneumophila is an important step forward in the understanding of how the switch from inoffensive, replicating to highly virulent, transmissive L. pneumophila is regulated. Copyright © 2017 Oliva et al.

MR-ARFI-based method for the quantitative measurement of tissue elasticity: application for monitoring HIFU therapy

NASA Astrophysics Data System (ADS)

Vappou, Jonathan; Bour, Pierre; Marquet, Fabrice; Ozenne, Valery; Quesson, Bruno

2018-05-01

Monitoring thermal therapies through medical imaging is essential in order to ensure that they are safe, efficient and reliable. In this paper, we propose a new approach, halfway between MR acoustic radiation force imaging (MR-ARFI) and MR elastography (MRE), allowing for the quantitative measurement of the elastic modulus of tissue in a highly localized manner. It relies on the simulation of the MR-ARFI profile, which depends on tissue biomechanical properties, and on the identification of tissue elasticity through the fitting of experimental displacement images measured using rapid MR-ARFI. This method was specifically developed to monitor MR-guided high intensity focused ultrasound (MRgHIFU) therapy. Elasticity changes were followed during HIFU ablations (N  =  6) performed ex vivo in porcine muscle samples, and were compared to temperature changes measured by MR-thermometry. Shear modulus was found to increase consistently and steadily a few seconds after the heating started, and such changes were found to be irreversible. The shear modulus was found to increase from 1.49  ±  0.48 kPa (before ablation) to 3.69  ±  0.93 kPa (after ablation and cooling). Thanks to its ability to perform quantitative elasticity measurements in a highly localized manner around the focal spot, this method proved to be particularly attractive for monitoring HIFU ablations.

Rhythm Defects Caused by Newly Engineered Null Mutations in Drosophila's cryptochrome Gene

PubMed Central

Dolezelova, Eva; Dolezel, David; Hall, Jeffrey C.

2007-01-01

Much of the knowledge about cryptochrome function in Drosophila stems from analyzing the cryb mutant. Several features of this variant's light responsiveness imply either that CRYb retains circadian-photoreceptive capacities or that additional CRY-independent light-input routes subserve these processes. Potentially to resolve these issues, we generated cry knock-out mutants (cry0's) by gene replacement. They behaved in an anomalously rhythmic manner in constant light (LL). However, cry0 flies frequently exhibited two separate circadian components in LL, not observed in most previous cryb analyses. Temperature-dependent circadian phenotypes exhibited by cry0 flies suggest that CRY is involved in core pacemaking. Further locomotor experiments combined cry0 with an externally blinding mutation (norpAP24), which caused the most severe decrements of circadian photoreception observed so far. cryb cultures were shown previously to exhibit either aperiodic or rhythmic eclosion in separate studies. We found cry0 to eclose in a solidly periodic manner in light:dark cycles or constant darkness. Furthermore, both cry0 and cryb eclosed rhythmically in LL. These findings indicate that the novel cry0 type causes more profound defects than does the cryb mutation, implying that CRYb retains residual activity. Because some norpAP24 cry0 individuals can resynchronize to novel photic regimes, an as-yet undetermined light-input route exists in Drosophila. PMID:17720919

Daucosterol inhibits cancer cell proliferation by inducing autophagy through reactive oxygen species-dependent manner.

PubMed

Zhao, Chuanke; She, Tiantian; Wang, Lixin; Su, Yahui; Qu, Like; Gao, Yujing; Xu, Shuo; Cai, Shaoqing; Shou, Chengchao

2015-09-15

This study aims to evaluate the anti-cancer effect of daucosterol and explore its possible mechanism. MTT and colony formation assay were performed to determine the effect of daucosterol on cancer cell proliferation in vitro. H22 allograft model was used for the assessment of its anti-cancer activity in vivo. Intracellular generation of reactive oxygen species (ROS) was measured using DCFH-DA probe with flow cytometry system and a laser scanning confocal microscope. LC3 (microtubule-associated protein 1 light chain 3)-II conversion was monitored with immunofluorescence and immunoblotting to demonstrate daucosterol-induced autophagy. We found that daucosterol inhibits the proliferation of human breast cancer cell line MCF-7 and gastric cancer cell lines MGC803, BGC823 and AGS in a dose-dependent manner. Furthermore, daucosterol inhibits murine hepatoma H22 cell growth in ICR mice. Daucosterol treatment induces intracellular ROS generation and autophagy, but not apoptotic cell death. Treatment with ROS scavenger GSH (reduced glutathione), NAC (N-acetyl-l-cysteine) or autophagy inhibitor 3-Methyladenine (3-MA) counteracted daucosterol-induced autophagy and growth inhibition in BGC823 and MCF-7 cancer cells. Daucosterol inhibits cancer cell proliferation by inducing autophagy through ROS-dependent manner and could be potentially developed as an anti-cancer agent. Copyright © 2015 Elsevier Inc. All rights reserved.

The contractile ring coordinates curvature-dependent septum assembly during fission yeast cytokinesis

PubMed Central

Zhou, Zhou; Munteanu, Emilia Laura; He, Jun; Ursell, Tristan; Bathe, Mark; Huang, Kerwyn Casey; Chang, Fred

2015-01-01

The functions of the actin-myosin–based contractile ring in cytokinesis remain to be elucidated. Recent findings show that in the fission yeast Schizosaccharomyces pombe, cleavage furrow ingression is driven by polymerization of cell wall fibers outside the plasma membrane, not by the contractile ring. Here we show that one function of the ring is to spatially coordinate septum cell wall assembly. We develop an improved method for live-cell imaging of the division apparatus by orienting the rod-shaped cells vertically using microfabricated wells. We observe that the septum hole and ring are circular and centered in wild-type cells and that in the absence of a functional ring, the septum continues to ingress but in a disorganized and asymmetric manner. By manipulating the cleavage furrow into different shapes, we show that the ring promotes local septum growth in a curvature-dependent manner, allowing even a misshapen septum to grow into a more regular shape. This curvature-dependent growth suggests a model in which contractile forces of the ring shape the septum cell wall by stimulating the cell wall machinery in a mechanosensitive manner. Mechanical regulation of the cell wall assembly may have general relevance to the morphogenesis of walled cells. PMID:25355954

Effects of celecoxib on cell apoptosis and Fas, FasL and Bcl-2 expression in a BGC-823 human gastric cancer cell line.

PubMed

Li, Qian; Peng, Jie; Liu, Ting; Zhang, Guiying

2017-09-01

Fas, which is an apoptotic-related protein, has an important role in cell apoptosis. Fas ligand (FasL) binds to Fas and activates apoptosis signal transduction. We previously demonstrated that the efficiency of celecoxib inhibited the proliferation and apoptosis of HT-29 colon cancer cell line. The BGC823 cell line was used as an experimental model to evaluate the potential role of celecoxib on gastric cancer cell apoptosis. Inhibitory effects of celecoxib on cell viability were determined by MTT assay. Cell apoptosis was evaluated by flow cytometric analysis and laser confocal microscopy. The results of the present study demonstrated that celecoxib inhibited the viability of BGC823 cells in a concentration- and time-dependent manner. Furthermore, the effect of BGC823 cells apoptosis was increased in a concentration-dependent manner. Western blotting was used to determine the protein expression levels of Fas, FasL, and B-cell lymphoma-2 (Bcl-2). During the celecoxib-induced apoptosis of BGC823 cells, celecoxib upregulated Fas expression and downregulated FasL and Bcl-2 expression in a concentration-dependent manner. These results suggest that celecoxib inhibited the growth and induced apoptosis of BGC823 gastric cancer cells by regulating the protein expression of Fas, FasL and Bcl-2.

ROS-mediated platelet generation: a microenvironment-dependent manner for megakaryocyte proliferation, differentiation, and maturation

PubMed Central

Chen, S; Su, Y; Wang, J

2013-01-01

Platelets have an important role in the body because of their manifold functions in haemostasis, thrombosis, and inflammation. Platelets are produced by megakaryocytes (MKs) that are differentiated from haematopoietic stem cells via several consecutive stages, including MK lineage commitment, MK progenitor proliferation, MK differentiation and maturation, cell apoptosis, and platelet release. During differentiation, the cells migrate from the osteoblastic niche to the vascular niche in the bone marrow, which is accompanied by reactive oxygen species (ROS)-dependent oxidation state changes in the microenvironment, suggesting that ROS can distinctly influence platelet generation and function in a microenvironment-dependent manner. The objective of this review is to reveal the role of ROS in regulating MK proliferation, differentiation, maturation, and platelet activation, thereby providing new insight into the mechanism of platelet generation, which may lead to the development of new therapeutic agents for thrombocytopenia and/or thrombosis. PMID:23846224

Nanoparticles modulate autophagic effect in a dispersity-dependent manner

NASA Astrophysics Data System (ADS)

Huang, Dengtong; Zhou, Hualu; Gao, Jinhao

2015-09-01

Autophagy plays a key role in human health and disease, especially in cancer and neurodegeneration. Many autophagy regulators are developed for therapy. Diverse nanomaterials have been reported to induce autophagy. However, the underlying mechanisms and universal rules remain unclear. Here, for the first time, we show a reliable and general mechanism by which nanoparticles induce autophagy and then successfully modulate autophagy via tuning their dispersity. Various well-designed univariate experiments demonstrate that nanomaterials induce autophagy in a dispersity-dependent manner. Aggregated nanoparticles induce significant autophagic effect in comparison with well-dispersed nanoparticles. As the highly stable nanoparticles may block autophagic degradation in autolysosomes, endocytosis and intracellular accumulation of nanoparticles can be responsible for this interesting phenomenon. Our results suggest dispersity-dependent autophagic effect as a common cellular response to nanoparticles, reveal the relationship between properties of nanoparticles and autophagy, and offer a new alternative way to modulate autophagy.

Surface Temperature Prediction of a Bridge for Tactical Decision Aide Modelling

DTIC Science & Technology

1988-01-01

Roadway And Piling Surface Temperature Predictions (No Radiosity Incident on Lower Surface) Compared to Temperature Estimates...Heat gained from water = Heat lost by long wave radiosity radiation. Algebraically, with the conduction term expressed in the same manner as for...5 10 15 20 LOCAL TIME (hrs.) Figure 8. Effect of No Radiosity Incident on Lower Surface. 37 U 8a M OT U% 60-- 0- o.. 20- 0- 1 T I I 5 10 15 20 LOCAL

Platelet-derived growth factor regulates K-Cl cotransport in vascular smooth muscle cells.

PubMed

Zhang, Jing; Lauf, Peter K; Adragna, Norma C

2003-03-01

Platelet-derived growth factor (PDGF), a potent serum mitogen for vascular smooth muscle cells (VSMCs), plays an important role in membrane transport regulation and in atherosclerosis. K-Cl cotransport (K-Cl COT/KCC), the coupled-movement of K and Cl, is involved in ion homeostasis. VSMCs possess K-Cl COT activity and the KCC1 and KCC3 isoforms. Here, we report on the effect of PDGF on K-Cl COT activity and mRNA expression in primary cultures of rat VSMCs. K-Cl COT was determined as the Cl-dependent Rb influx and mRNA expression by semiquantitative RT-PCR. Twenty four-hour serum deprivation inhibited basal K-Cl COT activity. Addition of PDGF increased total protein content and K-Cl COT activity in a time-dependent manner. PDGF activated K-Cl COT in a dose-dependent manner, both acutely (10 min) and chronically (12 h). AG-1296, a selective inhibitor of the PDGF receptor tyrosine kinase, abolished these effects. Actinomycin D and cycloheximide had no effect on the acute PDGF activation of K-Cl COT, suggesting posttranslational regulation by the drug. Furthermore, PDGF increased KCC1 and decreased KCC3 mRNA expression in a time-dependent manner. These results indicate that chronic activation of K-Cl COT activity by PDGF may involve regulation of the two KCC mRNA isoforms, with KCC1 playing a dominant role in the mechanism of PDGF-mediated activation.

Flavonoids and Tannins from Smilax china L. Rhizome Induce Apoptosis Via Mitochondrial Pathway and MDM2-p53 Signaling in Human Lung Adenocarcinoma Cells.

PubMed

Fu, San; Yang, Yanfang; Liu, Dan; Luo, Yan; Ye, Xiaochuan; Liu, Yanwen; Chen, Xin; Wang, Song; Wu, Hezhen; Wang, Yuhang; Hu, Qiwei; You, Pengtao

2017-01-01

In vitro evidence indicates that Smilax china L. rhizome (SCR) can inhibit cell proliferation. Therefore, in the present study, we analyzed the effects in vitro of SCR extracts on human lung adenocarcinoma A549 cells. Our results showed that A549 cell growth was inhibited in a dose- and time-dependent manner after treatment with SCR extracts. Total flavonoids and total tannins from SCR induced A549 apoptosis in a dose-dependent manner, as shown by our flow cytometry analysis, which was consistent with the alterations in nuclear morphology we observed. In addition, the total apoptotic rate induced by total tannins was higher than the rate induced by total flavonoids at the same dose. Cleaved-caspase-3 protein levels in A549 cells after treatment with total flavonoids or total tannins were increased in a dose-dependent manner, followed by the activation of caspase-8 and caspase-9, finally triggering to PARP cleavage. Furthermore, total flavonoids and total tannins increased the expression of Bax, decreased the expression of Bcl-2, and promoted cytochrome [Formula: see text] release. Moreover, MDM2 and p-MDM2 proteins were decreased, while p53 and p-p53 proteins were increased, both in a dose-dependent manner, after A549 treatment with total flavonoids and total tannins. Finally, cleaved-caspase-3 protein levels in the total flavonoids or total tannins-treated H1299 (p53 null) and p53-knockdown A549 cells were increased. Our results indicated that total flavonoids and total tannins from SCR exerted a remarkable effect in reducing A549 growth through their action on mitochondrial pathway and disruption of MDM2-p53 balance. Hence, our findings demonstrated a potential application of total flavonoids and total tannins from SCR in the treatment of human lung adenocarcinoma.

AtPP2CG1, a protein phosphatase 2C, positively regulates salt tolerance of Arabidopsis in abscisic acid-dependent manner

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

Liu, Xin, E-mail: fangfei6073@126.com; Zhu, Yanming, E-mail: ymzhu2001@neau.edu.cn; Zhai, Hong, E-mail: Zhai.h@neigaehrb.ac.cn

2012-06-15

Highlights: Black-Right-Pointing-Pointer AtPP2CG1 positively regulates salt tolerance in ABA-dependent manner. Black-Right-Pointing-Pointer AtPP2CG1 up-regulates the expression of marker genes in different pathways. Black-Right-Pointing-Pointer AtPP2CG1 expresses in the vascular system and trichomes of Arabidopsis. -- Abstract: AtPP2CG1 (Arabidopsis thaliana protein phosphatase 2C G Group 1) was predicted as an abiotic stress candidate gene by bioinformatic analysis in our previous study. The gene encodes a putative protein phosphatase 2C that belongs to Group G of PP2C. There is no report of Group G genes involved in abiotic stress so far. Real-time RT-PCR analysis showed that AtPP2CG1 expression was induced by salt, drought, andmore » abscisic acid (ABA) treatment. The expression levels of AtPP2CG1 in the ABA synthesis-deficient mutant abi2-3 were much lower than that in WT plants under salt stress suggesting that the expression of AtPP2CG1 acts in an ABA-dependent manner. Over-expression of AtPP2CG1 led to enhanced salt tolerance, whereas its loss of function caused decreased salt tolerance. These results indicate that AtPP2CG1 positively regulates salt stress in an ABA-dependent manner. Under salt treatment, AtPP2CG1 up-regulated the expression levels of stress-responsive genes, including RD29A, RD29B, DREB2A and KIN1. GUS activity was detected in roots, leaves, stems, flower, and trichomes of AtPP2CG1 promoter-GUS transgenic plants. AtPP2CG1 protein was localized in nucleus and cytoplasm via AtPP2CG1:eGFP and YFP:AtPP2CG1 fusion approaches.« less

Glucose and insulin do not decrease in a dose-dependent manner after increasing doses of mixed fibers that are consumed in muffins for breakfast.

PubMed

Willis, Holly J; Thomas, William; Eldridge, Alison L; Harkness, Laura; Green, Hilary; Slavin, Joanne L

2011-01-01

Conventional wisdom suggests that fiber consumption leads to lower postprandial glucose and insulin response. We hypothesized that increasing doses of mixed, viscous fiber would lower glucose and insulin levels in a dose-dependent manner. Healthy men (n = 10) and women (n = 10) with a body mass index of 24 ± 2 (mean ± SEM) participated in this double-blind, crossover study. On 4 separate visits, fasting subjects consumed an approximately 2093 kJ (500 calorie) muffin with 0, 4, 8, or 12 g of mixed fibers. Blood was drawn to measure glucose and insulin at regular intervals throughout a 3-hour test period. Area under the curve (AUC) glucose was significantly lower after 0 g of fiber than after 4, 8, or 12 g of fiber (arbitrary AUC units ± SEM: 25.3 ± 5.2 vs 44.6 ± 7.7, 49.7 ± 7.9, 51.5 ± 6.6, respectively; P < .006). Area under the curve glucose increased with increasing fiber doses (P for trend = .0003). Area under the curve insulin was higher after the 4-g dose than after the 0-, 8-, and 12-g doses (arbitrary AUC units ± SEM: 84.4 ± 8.0 vs 60.1 ± 6.5, 69.4 ± 8.7, 69.7 ± 8.5, respectively; P < .05); it did not change in a dose-dependent manner. Area under the curve glucose and AUC insulin did not correlate with each other. Glucose and insulin did not decrease in a dose-dependent manner after 0, 4, 8, and 12 g of mixed fibers were consumed in muffins for breakfast. The lack of differences was largely based on the individual variation in glucose response. Caution should be used when making general claims about the expected impact of fiber on glucose and insulin levels. Copyright © 2011 Elsevier Inc. All rights reserved.

The periplasmic domain of Escherichia coli outer membrane protein A can undergo a localized temperature dependent structural transition.

PubMed

Ishida, Hiroaki; Garcia-Herrero, Alicia; Vogel, Hans J

2014-12-01

Gram-negative bacteria such as Escherichia coli are surrounded by two membranes with a thin peptidoglycan (PG)-layer located in between them in the periplasmic space. The outer membrane protein A (OmpA) is a 325-residue protein and it is the major protein component of the outer membrane of E. coli. Previous structure determinations have focused on the N-terminal fragment (residues 1-171) of OmpA, which forms an eight stranded transmembrane β-barrel in the outer membrane. Consequently it was suggested that OmpA is composed of two independently folded domains in which the N-terminal β-barrel traverses the outer membrane and the C-terminal domain (residues 180-325) adopts a folded structure in the periplasmic space. However, some reports have proposed that full-length OmpA can instead refold in a temperature dependent manner into a single domain forming a larger transmembrane pore. Here, we have determined the NMR solution structure of the C-terminal periplasmic domain of E. coli OmpA (OmpA(180-325)). Our structure reveals that the C-terminal domain folds independently into a stable globular structure that is homologous to the previously reported PG-associated domain of Neisseria meningitides RmpM. Our results lend credence to the two domain structure model and a PG-binding function for OmpA, and we could indeed localize the PG-binding site on the protein through NMR chemical shift perturbation experiments. On the other hand, we found no evidence for binding of OmpA(180-325) with the TonB protein. In addition, we have also expressed and purified full-length OmpA (OmpA(1-325)) to study the structure of the full-length protein in micelles and nanodiscs by NMR spectroscopy. In both membrane mimetic environments, the recombinant OmpA maintains its two domain structure that is connected through a flexible linker. A series of temperature-dependent HSQC experiments and relaxation dispersion NMR experiments detected structural destabilization in the bulge region of the periplasmic domain of OmpA above physiological temperatures, which may induce dimerization and play a role in triggering the previously reported larger pore formation. Copyright © 2014 Elsevier B.V. All rights reserved.

Differential scanning calorimetric and Fourier transform infrared spectroscopic studies of the effects of cholesterol on the thermotropic phase behavior and organization of a homologous series of linear saturated phosphatidylserine bilayer membranes.

PubMed Central

McMullen, T P; Lewis, R N; McElhaney, R N

2000-01-01

We have examined the effects of cholesterol on the thermotropic phase behavior and organization of aqueous dispersions of a homologous series of linear disaturated phosphatidylserines by high-sensitivity differential scanning calorimetry and Fourier transform infrared spectroscopy. We find that the incorporation of increasing quantities of cholesterol progressively reduces the temperature, enthalpy, and cooperativity of the gel-to-liquid-crystalline phase transition of the host phosphatidylserine bilayer, such that a cooperative chain-melting phase transition is completely or almost completely abolished at 50 mol % cholesterol, in contrast to the results of previous studies. We are also unable to detect the presence of a separate anhydrous cholesterol or cholesterol monohydrate phase in our binary mixtures, again in contrast to previous reports. We further show that the magnitude of the reduction in the phase transition temperature induced by cholesterol addition is independent of the hydrocarbon chain length of the phosphatidylserine studied. This result contrasts with our previous results with phosphatidylcholine bilayers, where we found that cholesterol increases or decreases the phase transition temperature in a chain length-dependent manner (1993. Biochemistry, 32:516-522), but is in agreement with our previous results for phosphatidylethanolamine bilayers, where no hydrocarbon chain length-dependent effects were observed (1999. Biochim. Biophys. Acta, 1416:119-234). However, the reduction in the phase transition temperature by cholesterol is of greater magnitude in phosphatidylethanolamine as compared to phosphatidylserine bilayers. We also show that the addition of cholesterol facilitates the formation of the lamellar crystalline phase in phosphatidylserine bilayers, as it does in phosphatidylethanolamine bilayers, whereas the formation of such phases in phosphatidylcholine bilayers is inhibited by the presence of cholesterol. We ascribe the limited miscibility of cholesterol in phosphatidylserine bilayers reported previously to a fractional crystallization of the cholesterol and phospholipid phases during the removal of organic solvent from the binary mixture before the hydration of the sample. In general, the results of our studies to date indicate that the magnitude of the effect of cholesterol on the thermotropic phase behavior of the host phospholipid bilayer, and its miscibility in phospholipid dispersions generally, depend on the strength of the attractive interactions between the polar headgroups and the hydrocarbon chains of the phospholipid molecule, and not on the charge of the polar headgroups per se. PMID:11023909

Condensation-evaporator nanoparticle charger

DOEpatents

Hering, Susanne Vera; Spielman, Steven Russel; Lewis, Gregory Stephen

2017-02-28

A particle charging method and apparatus are provided. An ion source is applied to a particle laden flow. The flow is introduced into a container in a laminar manner. The container has at least a first section, a second section and a third section. The first section includes wetted walls at a first temperature. A second section adjacent to the first section has wetted walls at a second temperature T2 greater than the first temperature T1. A third section adjacent to the second section has dry walls provided at a temperature T3 equal to or greater than T2. Additional water removal and temperature conditioning sections may be provided.

Effect of primycin on growth-arrested cultures and cell integrity of Staphylococcus aureus.

PubMed

Feiszt, Péter; Schneider, György; Emődy, Levente

2017-06-01

Bactericidal effect against non-dividing bacteria is a very advantageous, but rare characteristic among antimicrobial agents, mostly possessed by those affecting the cell membrane. These kinds of agents can kill bacterial cells without lysis. We assessed these characteristics on primycin, a topical anti-staphylococcal agent highly effective against prevalent multiresistant strains, as it also acts on the cell membrane. In time-kill studies, primycin preserved its bactericidal activity against growth-arrested Staphylococcus aureus cultures. The bactericidal action was slower against growth-arrested cultures compared to the exponentially growing ones to different extents depending on the manner of arrest. The bactericidal effect was less influenced by stringent response and by protein synthesis inhibition, proving that it does not depend on metabolic activity. In contrast, uncoupling of the membrane potential predominantly slowed, and low temperature almost stopped killing of bacteria. In consideration of published data, these facts suggest that the antibacterial action of primycin involves disrupting of the membrane potential, and is predominantly influenced by the membrane fluidity. Optical density measurements and transmission electron microscopy verified that primycin kills bacterial cells without lysis. These results reveal favorable characteristics of primycin and point to, and broaden the knowledge on its membrane-targeted effect.

In Situ Forming Polymeric Drug Delivery Systems

PubMed Central

Madan, M.; Bajaj, A.; Lewis, S.; Udupa, N.; Baig, J. A.

2009-01-01

In situ forming polymeric formulations are drug delivery systems that are in sol form before administration in the body, but once administered, undergo gelation in situ, to form a gel. The formation of gels depends on factors like temperature modulation, pH change, presence of ions and ultra violet irradiation, from which the drug gets released in a sustained and controlled manner. Various polymers that are used for the formulation of in situ gels include gellan gum, alginic acid, xyloglucan, pectin, chitosan, poly(DL-lactic acid), poly(DL-lactide-co-glycolide) and poly-caprolactone. The choice of solvents like water, dimethylsulphoxide, N-methyl pyrrolidone, triacetin and 2-pyrrolidone for these formulations depends on the solubility of polymer used. Mainly in situ gels are administered by oral, ocular, rectal, vaginal, injectable and intraperitoneal routes. The in situ gel forming polymeric formulations offer several advantages like sustained and prolonged action in comparison to conventional drug delivery systems. The article presents a detailed review of these types of polymeric systems, their evaluation, advancements and their commercial formulations. From a manufacturing point of view, the production of such devices is less complex and thus lowers the investment and manufacturing cost. PMID:20490289

Exploration of dynamic dipole polarizability of impurity doped quantum dots in presence of noise

NASA Astrophysics Data System (ADS)

Ghosh, Anuja; Bera, Aindrila; Saha, Surajit; Arif, Sk. Md.; Ghosh, Manas

2018-02-01

Present study strives to perform a rigorous exploration of dynamic dipole polarizability (DDP) of GaAs quantum dot (QD) containing dopant with special reference to influence of Gaussian white noise. Several physical quantities have been varied over a range to observe the modulations of the DDP profiles. Aforesaid physical quantities include magnetic field, confinement potential, dopant location, dopant potential, noise strength, aluminium concentration (only for Alx Ga1 - x As alloy QD), position-dependent effective mass (PDEM), position-dependent dielectric screening function (PDDSF), anisotropy, hydrostatic pressure (HP) and temperature. The DDP profiles reveal noticeable characteristics governed by the particular physical quantity involved, presence/absence of noise, the manner (additive/multiplicative) noise is applied to the system and the incoming photon frequency. As a general observation we have found that additive noise causing greater deviation of the DDP profile from noise-free state than its multiplicative neighbor. The study highlights viable means of harnessing DDP of doped QD under the governance of noise by appropriate adjustment of several relevant factors. The study merits importance in the light of technological applications of QD-based devices where noise appears as an integral component.

Magnetoelastic couplings in the distorted diamond-chain compound azurite

NASA Astrophysics Data System (ADS)

Cong, Pham Thanh; Wolf, Bernd; Manna, Rudra Sekhar; Tutsch, Ulrich; de Souza, Mariano; Brühl, Andreas; Lang, Michael

2014-05-01

We present results of ultrasonic measurements on a single crystal of the distorted diamond-chain compound azurite Cu3(CO3)2(OH)2. Pronounced elastic anomalies are observed in the temperature dependence of the longitudinal elastic mode c22 which can be assigned to the relevant magnetic interactions in the system and their couplings to the lattice degrees of freedom. From a semiquantitative analysis of the magnetic contribution to c22 the magnetoelastic coupling G =∂J2/∂ɛb can be estimated, where J2 is the intradimer coupling constant and ɛb the strain along the intrachain b axis. We find an exceptionally large coupling constant of |G |˜ 3650 K highlighting an extraordinarily strong sensitivity of J2 against changes of the b-axis lattice parameter. These results are complemented by measurements of the hydrostatic pressure dependence of J2 by means of thermal expansion and magnetic susceptibility measurements performed both at ambient and finite hydrostatic pressure. We propose that a structural peculiarity of this compound, in which Cu2O6 dimer units are incorporated in an unusually stretched manner, is responsible for the anomalously large magnetoelastic coupling.

Intrapopulation Genome Size Variation in D. melanogaster Reflects Life History Variation and Plasticity

PubMed Central

Ellis, Lisa L.; Huang, Wen; Quinn, Andrew M.; Ahuja, Astha; Alfrejd, Ben; Gomez, Francisco E.; Hjelmen, Carl E.; Moore, Kristi L.; Mackay, Trudy F. C.; Johnston, J. Spencer; Tarone, Aaron M.

2014-01-01

We determined female genome sizes using flow cytometry for 211 Drosophila melanogaster sequenced inbred strains from the Drosophila Genetic Reference Panel, and found significant conspecific and intrapopulation variation in genome size. We also compared several life history traits for 25 lines with large and 25 lines with small genomes in three thermal environments, and found that genome size as well as genome size by temperature interactions significantly correlated with survival to pupation and adulthood, time to pupation, female pupal mass, and female eclosion rates. Genome size accounted for up to 23% of the variation in developmental phenotypes, but the contribution of genome size to variation in life history traits was plastic and varied according to the thermal environment. Expression data implicate differences in metabolism that correspond to genome size variation. These results indicate that significant genome size variation exists within D. melanogaster and this variation may impact the evolutionary ecology of the species. Genome size variation accounts for a significant portion of life history variation in an environmentally dependent manner, suggesting that potential fitness effects associated with genome size variation also depend on environmental conditions. PMID:25057905

In C. elegans, high levels of dsRNA allow RNAi in the absence of RDE-4.

PubMed

Habig, Jeffrey W; Aruscavage, P Joseph; Bass, Brenda L

2008-01-01

C. elegans Dicer requires an accessory double-stranded RNA binding protein, RDE-4, to enact the first step of RNA interference, the cleavage of dsRNA to produce siRNA. While RDE-4 is typically essential for RNAi, we report that in the presence of high concentrations of trigger dsRNA, rde-4 deficient animals are capable of silencing a transgene. By multiple criteria the silencing occurs by the canonical RNAi pathway. For example, silencing is RDE-1 dependent and exhibits a decrease in the targeted mRNA in response to an increase in siRNA. We also find that high concentrations of dsRNA trigger lead to increased accumulation of primary siRNAs, consistent with the existence of a rate-limiting step during the conversion of primary to secondary siRNAs. Our studies also revealed that transgene silencing occurs at low levels in the soma, even in the presence of ADARs, and that at least some siRNAs accumulate in a temperature-dependent manner. We conclude that an RNAi response varies with different conditions, and this may allow an organism to tailor a response to specific environmental signals.

In C. elegans, High Levels of dsRNA Allow RNAi in the Absence of RDE-4

PubMed Central

Habig, Jeffrey W.; Aruscavage, P. Joseph; Bass, Brenda L.

2008-01-01

C. elegans Dicer requires an accessory double-stranded RNA binding protein, RDE-4, to enact the first step of RNA interference, the cleavage of dsRNA to produce siRNA. While RDE-4 is typically essential for RNAi, we report that in the presence of high concentrations of trigger dsRNA, rde-4 deficient animals are capable of silencing a transgene. By multiple criteria the silencing occurs by the canonical RNAi pathway. For example, silencing is RDE-1 dependent and exhibits a decrease in the targeted mRNA in response to an increase in siRNA. We also find that high concentrations of dsRNA trigger lead to increased accumulation of primary siRNAs, consistent with the existence of a rate-limiting step during the conversion of primary to secondary siRNAs. Our studies also revealed that transgene silencing occurs at low levels in the soma, even in the presence of ADARs, and that at least some siRNAs accumulate in a temperature-dependent manner. We conclude that an RNAi response varies with different conditions, and this may allow an organism to tailor a response to specific environmental signals. PMID:19112503

Characterization of insulin-like growth factor I receptor on human erythrocytes.

PubMed

Hizuka, N; Takano, K; Tanaka, I; Honda, N; Tsushima, T; Shizume, K

1985-12-01

[125I]Insulin-like growth factor I (IGF-I) specifically bound to erythrocytes; the binding was saturable, and time and temperature dependent. Steady state binding was reached at 16 h at 4 C, and specific binding averaged 14.3 +/- 0.7% (+/- SEM) at a concentration of 3.6 X 10(9) cells/ml in seven normal subjects. [125I]IGF-I binding to the cells was displaced by unlabeled IGF-I in a dose-dependent manner. Scatchard analysis indicated a linear plot, and Ka and number of binding sites/cell were 1.43 +/- 0.07 X 10(9) M-1 and 20.7 +/- 2.2, respectively. Compared to IGF-I, the relative potencies of multiplication-stimulating activity and insulin for displacing [125I]IGF-I binding were 20% and 1%, respectively. [125I]IGF-I binding to erythrocytes from patients with acromegaly was lower than binding to cells from pituitary dwarfs. An inverse correlation between plasma IGF-I level and the number of IGF-I-binding sites per cell was found (r = -0.75; P less than 0.005). These results demonstrate that [125I]IGF-I binding to erythrocytes can be used for clinical measurement of the IGF-I receptor.

The descent into glass formation in polymer fluids.

PubMed

Freed, Karl F

2011-03-15

Glassy materials have been fundamental to technology since the dawn of civilization and remain so to this day: novel glassy systems are currently being developed for applications in energy storage, electronics, food, drugs, and more. Glass-forming fluids exhibit a universal set of transitions beginning at temperatures often in excess of twice the glass transition temperature T(g) and extending down to T(g), below which relaxation becomes so slow that systems no longer equilibrate on experimental time scales. Despite the technological importance of glasses, no prior theory explains this universal behavior nor describes the huge variations in the properties of glass-forming fluids that result from differences in molecular structure. Not surprisingly, the glass transition is currently regarded by many as the deepest unsolved problem in solid state theory. In this Account, we describe our recently developed theory of glass formation in polymer fluids. Our theory explains the origin of four universal characteristic temperatures of glass formation and their dependence on monomer-monomer van der Waals energies, conformational energies, and pressure and, perhaps most importantly, on molecular details, such as monomer structure, molecular weight, size of side groups, and so forth. The theory also provides a molecular explanation for fragility, a parameter that quantifies the rate of change with temperature of the viscosity and other dynamic mechanical properties at T(g). The fragility reflects the fluid's thermal sensitivity and determines the manner in which glass-formers can be processed, such as by extrusion, casting, or inkjet spotting. Specifically, the theory describes the change in thermodynamic properties and fragility of polymer glasses with variations in the monomer structure, the rigidity of the backbone and side groups, the cohesive energy, and so forth. The dependence of the structural relaxation time at lower temperatures emerges from the theory as the Vogel-Fulcher equation, whereas pressure and concentration analogs of the Vogel-Fulcher expression follow naturally from the theory with no additional assumptions. The computed dependence of T(g) and fragility on the length of the side group in poly(α-olefins) agrees quite well with observed trends, demonstrating that the theory can be utilized, for instance, to guide the tailoring of T(g) and the fragility of glass-forming polymer fluids in the fabrication of new materials. Our calculations also elucidate the molecular characteristics of small-molecule diluents that promote antiplasticization, a lowering of T(g) and a toughening of the material. © 2011 American Chemical Society

Advanced modelling of the transport phenomena across horizontal clothing microclimates with natural convection.

PubMed

Mayor, T S; Couto, S; Psikuta, A; Rossi, R M

2015-12-01

The ability of clothing to provide protection against external environments is critical for wearer's safety and thermal comfort. It is a function of several factors, such as external environmental conditions, clothing properties and activity level. These factors determine the characteristics of the different microclimates existing inside the clothing which, ultimately, have a key role in the transport processes occurring across clothing. As an effort to understand the effect of transport phenomena in clothing microclimates on the overall heat transport across clothing structures, a numerical approach was used to study the buoyancy-driven heat transfer across horizontal air layers trapped inside air impermeable clothing. The study included both the internal flow occurring inside the microclimate and the external flow occurring outside the clothing layer, in order to analyze the interdependency of these flows in the way heat is transported to/from the body. Two-dimensional simulations were conducted considering different values of microclimate thickness (8, 25 and 52 mm), external air temperature (10, 20 and 30 °C), external air velocity (0.5, 1 and 3 m s(-1)) and emissivity of the clothing inner surface (0.05 and 0.95), which implied Rayleigh numbers in the microclimate spanning 4 orders of magnitude (9 × 10(2)-3 × 10(5)). The convective heat transfer coefficients obtained along the clothing were found to strongly depend on the transport phenomena in the microclimate, in particular when natural convection is the most important transport mechanism. In such scenario, convective coefficients were found to vary in wavy-like manner, depending on the position of the flow vortices in the microclimate. These observations clearly differ from data in the literature for the case of air flow over flat-heated surfaces with constant temperature (which shows monotonic variations of the convective heat transfer coefficients, along the length of the surface). The flow patterns and temperature fields in the microclimates were found to strongly depend on the characteristics of the external boundary layer forming along the clothing and on the distribution of temperature in the clothing. The local heat transfer rates obtained in the microclimate are in marked contrast with those found in the literature for enclosures with constant-temperature active walls. These results stress the importance of coupling the calculation of the internal and the external flows and of the heat transfer convective and radiative components, when analyzing the way heat is transported to/from the body.

Surface properties of functional polymer systems

NASA Astrophysics Data System (ADS)

Wong, Derek

Polymer surface modification typically involves blending with other polymers or chemical modification of the parent polymer. Such strategies inevitably result in polymer systems that are spatially and chemically heterogeneous, and which exhibit the phenomenon of surface segregation. This work investigates the effects of chain architecture on the surface segregation behavior of such functionally modified polymers using a series of end- and center-fluorinated poly(D,L-lactide). Surface segregation of the fluorinated functional groups was observed in both chain architectures via AMPS and water contact angle. Higher surface segregation was noted for functional groups located at the chain end as opposed to those in the middle of the chain. A self-consistent mean-field lattice theory was used to model the composition depth profiles of functional groups and excellent agreement was found between the model predictions and the experimental AMPS data in both chain architectures. Polymer properties are also in general dependent on both time and temperature, and exhibit a range of relaxation times in response to environmental stimuli. This behavior arises from the characteristic frequencies of molecular motions of the polymer chain and the interrelationship between time and temperature has been widely established for polymer bulk properties. There is evidence that surface properties also respond in a manner that is time and temperature dependent and that this dependence may not be the same as that observed for bulk properties. AMPS and water contact angle experiments were used to investigate the surface reorganization behavior of functional groups using a series of anionically synthesized end-fluorinated and end-carboxylated poly(styrene). It was found that both types of functional end-groups reorganized upon a change in the polarity of the surface environment in order to minimize the surface free energy. ADXPS and contact angle results suggest that the reorganization depth was confined to the top 2--3 nm of the surface. Contact angle results showed also that the reorganization process proceeded as a function of (time) 1/2, indicating that it is likely diffusion controlled. The magnitudes of the activation energies determined from the experimental data according to the Arhenius equation, suggest that the process is possibly correlated with known bulk beta and gamma relaxations in the polymer.

Effects of counterion size and backbone rigidity on the dynamics of ionic polymer melts and glasses

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

Fu, Yao; Bocharova, Vera; Ma, Mengze

Backbone rigidity, counterion size and the static dielectric constant affect the glass transition temperature, segmental relaxation time and decoupling between counterion and segmental dynamics in significant manners.

Differential effects of temperature and glucose on glycogenolytic enzymes in tissues of rainbow trout (Oncorhynchus mykiss).

PubMed

Bolinger, Mark T; Rodnick, Kenneth J

2014-05-01

The pathways and regulatory mechanisms of glycogenolysis remain relatively unexplored in non-mammalian vertebrates, especially poikilotherms. We studied the temperature sensitivity and inhibition of glycogenolytic enzymes in liver, ventricle, and white muscle of rainbow trout acclimated to 14 °C. Glycogen phosphorylase (GP) and acid α-glucosidase (GAA) activities were measured in homogenates of tissues at physiological temperatures (4, 14, and 24 °C), and in the presence of allosteric inhibitor, glucose. Higher GP versus GAA activity in all three tissues suggested a predominance of phosphorolytic glycogenolysis over the lysosomal glucosidic pathway. GP activities at 14 °C were ~2-fold higher in the ventricle and white muscle versus the liver and selectively increased by AMP in striated muscle. Conversely, the activities of GAA and lysosomal marker acid phosphatase were 8- to 10-fold higher in the liver compared with the ventricle and white muscle. Thermal sensitivity (Q10) was increased for GP in all tissues below 14 °C and decreased in striated muscle in the absence of AMP above 14 °C. GAA had lower Q10 values than GP below 14 °C, and, unlike GP, Q10s for GAA were not different between tissues or affected by temperature. Both GP (in the absence of AMP) and GAA were inhibited by glucose in a dose-dependent manner, with the lowest IC50 values observed in the white muscle (1.4 and 6.3 mM, respectively). In conclusion, despite comparatively low kinetic potential, lysosomal GAA might facilitate glycogenolysis at colder body temperatures in striated muscle and intracellular glucose could limit phosphorolytic and glucosidic glycogenolysis in multiple tissues of the rainbow trout. Copyright © 2014 Elsevier Inc. All rights reserved.

Structural changes and fluctuations of proteins. I. A statistical thermodynamic model.

PubMed

Ikegami, A

1977-01-01

A general theory of the structural changes and fluctuations of proteins has been proposed based on statistical thermodynamic considerations at the chain level. The "structure" of protein was assumed to be characterized by the state of secondary bonds between unique pairs of specific sites on peptide chains. Every secondary bond changes between the bonded and unbonded states by thermal agitation and the "structure" is continuously fluctuating. The free energy of the "structural state" that is defined by the fraction of secondary bonds in the bonded state has been expressed by the bond energy, the cooperative interaction between bonds, the mixing entropy of bonds, and the entropy of polypeptide chains. The most probable "structural state" can be simply determined by graphical analysis and the effect of temperature or solvent composition on it is discussed. The temperature dependence of the free energy, the probability distribution of structural states and the specific heat have been calculted for two examples of structural change. The theory predicts two different types of structural changes from the ordered to disorderd state, a "structured transition" and a "gradual structural change" with rising temperature. In the "structural transition", the probability distribution has two maxima in the temperature range of transition. In the "gradual structural change", the probabilty distribution has only one maximum during the change. A considerable fraction of secondary bonds is in the unbounded state and is always fluctuating even in the ordered state at room temperature. Such structural flucutations in a single protein molecule have been discussed quantitatively. The theory is extended to include small molecules which bind to the protein molecule and affect the structural state. The changes of structural state caused by specific and non-specific binding and allosteric effects are explained in a unified manner.

Ice age fish in a warming world: minimal variation in thermal acclimation capacity among lake trout (Salvelinus namaycush) populations

PubMed Central

Kelly, Nicholas I.; Burness, Gary; McDermid, Jenni L.; Wilson, Chris C.

2014-01-01

In the face of climate change, the persistence of cold-adapted species will depend on their adaptive capacity for physiological traits within and among populations. The lake trout (Salvelinus namaycush) is a cold-adapted salmonid and a relict from the last ice age that is well suited as a model species for studying the predicted effects of climate change on coldwater fishes. We investigated the thermal acclimation capacity of upper temperature resistance and metabolism of lake trout from four populations across four acclimation temperatures. Individuals were reared from egg fertilization onward in a common environment and, at 2 years of age, were acclimated to 8, 11, 15 or 19°C. Although one population had a slightly higher maximal metabolic rate (MMR), higher metabolic scope for activity and faster metabolic recovery across all temperatures, there was no interpopulation variation for critical thermal maximum (CTM) or routine metabolic rate (RMR) or for the thermal acclimation capacity of CTM, RMR, MMR or metabolic scope. Across the four acclimation temperatures, there was a 3°C maximal increase in CTM and 3-fold increase in RMR for all populations. Above 15°C, a decline in MMR and increase in RMR resulted in sharply reduced metabolic scope for all populations acclimated at 19°C. Together, these data suggest there is limited variation among lake trout populations in thermal physiology or capacity for thermal acclimatization, and that climate change may impact lake trout populations in a similar manner across a wide geographical range. Understanding the effect of elevated temperatures on the thermal physiology of this economically and ecologically important cold-adapted species will help inform management and conservation strategies for the long-term sustainability of lake trout populations. PMID:27293646

Molecular stress-inducing compounds increase osteoclast formation in a heat shock factor 1 protein-dependent manner.

PubMed

Chai, Ryan C; Kouspou, Michelle M; Lang, Benjamin J; Nguyen, Chau H; van der Kraan, A Gabrielle J; Vieusseux, Jessica L; Lim, Reece C; Gillespie, Matthew T; Benjamin, Ivor J; Quinn, Julian M W; Price, John T

2014-05-09

Many anticancer therapeutic agents cause bone loss, which increases the risk of fractures that severely reduce quality of life. Thus, in drug development, it is critical to identify and understand such effects. Anticancer therapeutic and HSP90 inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) causes bone loss by increasing osteoclast formation, but the mechanism underlying this is not understood. 17-AAG activates heat shock factor 1 (Hsf1), the master transcriptional regulator of heat shock/cell stress responses, which may be involved in this negative action of 17-AAG upon bone. Using mouse bone marrow and RAW264.7 osteoclast differentiation models we found that HSP90 inhibitors that induced a heat shock response also enhanced osteoclast formation, whereas HSP90 inhibitors that did not (including coumermycin A1 and novobiocin) did not affect osteoclast formation. Pharmacological inhibition or shRNAmir knockdown of Hsf1 in RAW264.7 cells as well as the use of Hsf1 null mouse bone marrow cells demonstrated that 17-AAG-enhanced osteoclast formation was Hsf1-dependent. Moreover, ectopic overexpression of Hsf1 enhanced 17-AAG effects upon osteoclast formation. Consistent with these findings, protein levels of the essential osteoclast transcription factor microphthalmia-associated transcription factor were increased by 17-AAG in an Hsf1-dependent manner. In addition to HSP90 inhibitors, we also identified that other agents that induced cellular stress, such as ethanol, doxorubicin, and methotrexate, also directly increased osteoclast formation, potentially in an Hsf1-dependent manner. These results, therefore, indicate that cellular stress can enhance osteoclast differentiation via Hsf1-dependent mechanisms and may significantly contribute to pathological and therapeutic related bone loss.

Chloride Fluxes in Isolated Dialyzed Barnacle Muscle Fibers

PubMed Central

DiPolo, R.

1972-01-01

Chloride outflux and influx has been studied in single isolated muscle fibers from the giant barnacle under constant internal composition by means of a dialysis perfusion technique. Membrane potential was continually recorded. The chloride outfluxes and influxes were 143 and 144 pmoles/cm2-sec (mean resting potential: 58 mv, temperature: 22°–24°C) with internal and external chloride concentrations of 30 and 541 mM, respectively. The chloride conductance calculated from tracer measurements using constant field assumptions is about fourfold greater than that calculated from published electrical data. Replacing 97% of the external chloride ions by propionate reduces the chloride efflux by 51%. Nitrate ions applied either to the internal or external surface of the membrane slows the chloride efflux. The external pH dependence of the chloride efflux follows the external pH dependence of the membrane conductance, in the range pH 3.9–4.7, increasing with decreasing pH. In the range pH 5–9, the chloride efflux increased with increasing pH, in a manner similar to that observed in frog muscle fibers. The titration curve for internal pH changes in the range 4.0–7.0 was quantitatively much different from that for external pH change, indicating significant asymmetry in the internal and external pH dependence of the chloride efflux. PMID:5074810

Absorption of resveratrol by vascular endothelial cells through passive diffusion and an SGLT1-mediated pathway.

PubMed

Chen, Ming-liang; Yi, Long; Jin, Xin; Xie, Qi; Zhang, Ting; Zhou, Xi; Chang, Hui; Fu, Yu-jie; Zhu, Jun-dong; Zhang, Qian-yong; Mi, Man-tian

2013-11-01

Resveratrol is a natural polyphenol that exerts potent effects to suppress atherosclerosis. However, its low concentration in plasma has placed this role in doubt. Thus, resveratrol effects might be dependent on its transport into vascular endothelium, a question not previously addressed in spite of its obvious and fundamental importance. Via high-performance liquid chromatography and liquid chromatography/mass spectrometry, we found that resveratrol was absorbed by human umbilical vein endothelial cells in a temperature-, concentration- and time-dependent manner, suggesting the involvement of passive diffusion and active transport. As determined by confocal laser scanning microscopy, resveratrol primarily distributed throughout the cytoplasm. Furthermore, resveratrol absorption was modulated by serum proteins and sodium-dependent glucose transporter 1 (SGLT1) yet inhibited by glucose (an SGLT1 substrate) and phlorizin (an SGLT1 selective inhibitor), as well as SGLT1 siRNA transfection. Additionally, Sprague-Dawley rats were intragastrically administrated with 100mg/kg of resveratrol and the concentration of resveratrol in blood vessels declined more slowly up to 24h compared to that in the blood. Our results suggested that resveratrol uptake by vascular endothelial cells involved both passive diffusion and an SGLT1-mediated process, at least partially. Moreover, the intracellular resveratrol pool may be more important than the serum level in vivo. These provide new insights into the cardiovascular benefits of resveratrol. Copyright © 2013 Elsevier Inc. All rights reserved.

ADP-ribosylation factor arf6p may function as a molecular switch of new end take off in fission yeast

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

Fujita, Atsushi

2008-02-01

Small GTPases act as molecular switches in a wide variety of cellular processes. In fission yeast Schizosaccharomyces pombe, the directions of cell growth change from a monopolar manner to a bipolar manner, which is known as 'New End Take Off' (NETO). Here I report the identification of a gene, arf6{sup +}, encoding an ADP-ribosylation factor small GTPase, that may be essential for NETO. arf6{delta} cells completely fail to undergo NETO. arf6p localizes at both cell ends and presumptive septa in a cell-cycle dependent manner. And its polarized localization is not dependent on microtubules, actin cytoskeletons and some NETO factors (bud6p,more » for3p, tea1p, tea3p, and tea4p). Notably, overexpression of a fast GDP/GTP-cycling mutant of arf6p can advance the timing of NETO. These findings suggest that arf6p functions as a molecular switch for the activation of NETO in fission yeast.« less

Toxicity evaluation of pH dependent stable Achyranthes aspera herbal gold nanoparticles

NASA Astrophysics Data System (ADS)

Tripathi, Alok; Kumari, Sarika; Kumar, Arvind

2016-01-01

Nanoparticles have gained substantial attention for the control of various diseases. However, any adverse effect of herbal gold nanoparticles (HGNPs) on animals including human being has not been investigated in details. The objectives of current study are to assess the cytotoxicity of HGNPs synthesized by using leaf extract of Achyranthes aspera, and long epoch stability. The protocol deals with stability of HGNPs in pH dependent manner. Visually, HGNPs formation is characterized by colour change of extract from dark brown to dark purple after adding gold chloride solution (1 mM). The 100 μg/ml HGNPs concentration has been found nontoxic to the cultured spleenocyte cells. Spectrophotometric analysis of nanoparticles solution gave a peak at 540 nm which corresponds to surface plasmon resonance absorption band. As per scanning electron microscopy and Transmission electron microscopy (TEM), size of HGNPs are in the range of 50-80 nm (average size 70 nm) with spherical morphology. TEM-selected area electron diffraction observation showed hexagonal texture. HGNPs showed substantial stability at higher temperature (85 °C), pH 10 and salt concentration (5 M). The zeta potential value of HGNPs is -35.9 mV at temperature 25 °C, pH 10 showing its good quality with better stability in comparison to pH 6 and pH 7. The findings advocate that the protocol for the synthesis of HGNPs is easy and quick with good quality and long epoch stability at pH 10. Moreover, non-toxic dose could be widely applicable for human health as a potential nano-medicine in the future to cure diseases.

Galleria mellonella as an in vivo model for assessing the efficacy of antimicrobial agents against Enterobacter cloacae infection.

PubMed

Yang, Hai-Fei; Pan, Ai-Jun; Hu, Li-Fen; Liu, Yan-Yan; Cheng, Jun; Ye, Ying; Li, Jia-Bin

2017-02-01

Enterobacter cloacae is a well-recognized nosocomial pathogen. Use of a rapid, in vivo infection model for E. cloacae that can determine the efficacy of antibiotic therapies could help facilitate screening for new treatments. Nonmammalian model systems of infection, such as Galleria mellonella, have significant logistical and ethical advantages over mammalian models. We utilized G. mellonella larvae to determine the utility of this infection model to study antibacterial efficacy. G. mellonella killing with heat-killed or live clinical isolates (E. cloacae GN1059 and GN0791) was tested. We also investigated the effect of postinoculation incubation temperature on the survival of infected larvae. The protection of administration of antibiotics to infected larvae was investigated. Finally, we determined the G. mellonella hemolymph burden of E. cloacae after administration of different antibiotics. With live bacterial inocula, G. mellonella killing was significantly dependent on the number of E. cloacae cells injected in a dose-dependent manner. Further, we observed that survival was reduced with increasing the postinoculation temperature. Treatment of a lethal E. cloacae infection with antibiotics that had in vitro activity significantly prolonged the survival of larvae compared with treatment with antibiotics to which the bacteria were resistant. The therapeutic benefit arising from administration of antibiotic correlated with a reduced burden of E. cloacae cells in the hemolymph. The G. mellonella infection model has the potential to be used to facilitate the in vivo study of host-pathogen interactions in E. cloacae and the efficacy of antibacterial agents. Copyright © 2014. Published by Elsevier B.V.

White and blue light induce reduction in susceptibility to minocycline and tigecycline in Acinetobacter spp. and other bacteria of clinical importance.

PubMed

Ramírez, María Soledad; Traglia, German Matías; Pérez, Jorgelina Fernanda; Müller, Gabriela Leticia; Martínez, María Florencia; Golic, Adrián Ezequiel; Mussi, María Alejandra

2015-05-01

Minocycline (MIN) and tigecycline (TIG) are antibiotics currently used for treatment of multidrug-resistant nosocomial pathogens. In this work, we show that blue light, as well as white light, modulates susceptibility to these antibiotics in a temperature-dependent manner. The modulation of susceptibility by light depends on the content of iron; an increase in iron results in a reduction in antibiotic susceptibility both under light and in the dark, though the effect is more pronounced in the latter condition. We further provide insights into the mechanism by showing that reduction in susceptibility to MIN and TIG induced by light is likely triggered by the generation of (1)O2, which, by a yet unknown mechanism, would ultimately lead to the activation of resistance genes such as those coding for the efflux pump AdeABC. The clinical relevance of these results may lie in surface-exposed wound infections, given the exposure to light in addition to the relatively low temperatures recorded in this type of lesion. We further show that the modulation of antibiotic susceptibility occurs not only in Acinetobacter baumannii but also in other micro-organisms of clinical relevance such as Escherichia coli and Staphylococcus aureus. Overall, our findings allow us to suggest that MIN and TIG antibiotic treatments may be improved by the inclusion of an iron chelator, in addition to keeping the wounds in the dark, a condition that would increase the effectiveness in the control of infections involving these micro-organisms. © 2015 The Authors.

DPY-17 and MUA-3 Interact for Connective Tissue-Like Tissue Integrity in Caenorhabditis elegans: A Model for Marfan Syndrome.

PubMed

Fotopoulos, Pauline; Kim, Jeongho; Hyun, Moonjung; Qamari, Waiss; Lee, Inhwan; You, Young-Jai

2015-04-27

mua-3 is a Caenorhabditis elegans homolog of the mammalian fibrillin1, a monogenic cause of Marfan syndrome. We identified a new mutation of mua-3 that carries an in-frame deletion of 131 amino acids in the extracellular domain, which allows the mutants to survive in a temperature-dependent manner; at the permissive temperature, the mutants grow normally without obvious phenotypes, but at the nonpermissive temperature, more than 90% die during the L4 molt due to internal organ detachment. Using the temperature-sensitive lethality, we performed unbiased genetic screens to isolate suppressors to find genetic interactors of MUA-3. From two independent screens, we isolated mutations in dpy-17 as a suppressor. RNAi of dpy-17 in mua-3 rescued the lethality, confirming dpy-17 is a suppressor. dpy-17 encodes a collagen known to genetically interact with dpy-31, a BMP-1/Tolloid-like metalloprotease required for TGFβ activation in mammals. Human fibrillin1 mutants fail to sequester TGFβ2 leading to excess TGFβ signaling, which in turn contributes to Marfan syndrome or Marfan-related syndrome. Consistent with that, RNAi of dbl-1, a TGFβ homolog, modestly rescued the lethality of mua-3 mutants, suggesting a potentially conserved interaction between MUA-3 and a TGFβ pathway in C. elegans. Our work provides genetic evidence of the interaction between TGFβ and a fibrillin homolog, and thus provides a simple yet powerful genetic model to study TGFβ function in development of Marfan pathology. Copyright © 2015 Fotopoulos et al.

Cadmium and high temperature effects on brain and behaviour of Lymantria dispar L. caterpillars originating from polluted and less-polluted forests.

PubMed

Perić-Mataruga, Vesna; Petković, Branka; Ilijin, Larisa; Mrdaković, Marija; Dronjak Čučaković, Slađana; Todorović, Dajana; Vlahović, Milena

2017-10-01

Insects brain as a part of nervous system is the first-line of fast stress response that integrate stress signals to regulate all aspects of insect physiology and behaviour. The cadmium (Cd) bioaccumulation factor (BF), activity of the neurotoxicity biomarker acetylcholinesterase (AChE), dopamine content, expression and amount of Hsp70 in the brain and locomotor activity were evaluated in the 4th instar of Lymantria dispar L. caterpillars fed a Cd supplemented diet and reared in an optimal temperature regime (23 °C) and/or exposed to high temperature (28 °C). The insects originated from two forests, one close to "Nikola Tesla" thermoelectric power plant, Obrenovac (polluted population), and the other Kosmaj mountain (less-polluted population, far from any industrial region). The Cd BF was higher in the less-polluted than in the polluted population especially at the high ambient temperature. AChE activity and dopamine content were changed in the brains of L. dispar from both populations in the same manner. Hsp70 concentration in caterpillar brains showed opposite trends, a decrease in the less-polluted and an increase in the polluted population. Locomotor activity was modified in both Lymantria dispar populations, but the pattern of changes depended on the stressors and their combined effect. ACh activity and dopamine content are sensitive parameters to Cd exposure, regardless of pollutant experience, and might be promising biomarkers in monitoring forest ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Activation of Neurokinin 3 Receptors in the Median Preoptic Nucleus Decreases Core Temperature in the Rat

PubMed Central

Dacks, Penny A.; Krajewski, Sally J.

2011-01-01

Estrogens have pronounced effects on thermoregulation, as illustrated by the occurrence of hot flushes secondary to estrogen withdrawal in menopausal women. Because neurokinin B (NKB) gene expression is markedly increased in the infundibular (arcuate) nucleus of postmenopausal women, and is modulated by estrogen withdrawal and replacement in multiple species, we have hypothesized that NKB neurons could play a role in the generation of flushes. There is no information, however, on whether the primary NKB receptor [neurokinin 3 receptor (NK3R)] modulates body temperature in any species. Here, we determine the effects of microinfusion of a selective NK3R agonist (senktide) into the rat median preoptic nucleus (MnPO), an important site in the heat-defense pathway. Senktide microinfusion into the rat MnPO decreased core temperature in a dose-dependent manner. The hypothermia induced by senktide was similar in ovariectomized rats with and without 17β-estradiol replacement. The hypothermic effect of senktide was prolonged in rats exposed to an ambient temperature of 29.0 C, compared with 21.5 C. Senktide microinfusion also altered tail skin vasomotion in rats exposed to an ambient temperature of 29.0 but not 21.5 C. Comparisons of the effects of senktide at different ambient temperatures indicated that the hypothermia was not secondary to thermoregulatory failure or a reduction in cold-induced thermogenesis. Other than a very mild increase in drinking, senktide microinfusion did not affect behavior. Terminal fluorescent dextran microinfusion showed targeting of the MnPO and adjacent septum, and immunohistochemical studies revealed that senktide induced a marked increase in Fos-activation in the MnPO. Because MnPO neurons expressed NK3R-immunoreactivity, the induction of MnPO Fos by senktide is likely a direct effect. By demonstrating that NK3R activation in the MnPO modulates body temperature, these studies support the hypothesis that hypothalamic NKB neurons could be involved in the generation of menopausal flushes. PMID:22028440

Phloretin Inhibits Platelet-derived Growth Factor-BB-induced Rat Aortic Smooth Muscle Cell Proliferation, Migration, and Neointimal Formation After Carotid Injury.

PubMed

Wang, Dong; Wang, Qingjie; Yan, Gaoliang; Qiao, Yong; Tang, Chengchun

2015-05-01

Abnormal vascular smooth muscle cell proliferation and migration are key factors in many cardiovascular diseases. Here, we investigated the effects of phloretin on platelet-derived growth factor homodimer (PDGF-BB)-induced rat aortic smooth muscle cell (RASMC) proliferation, migration, and neointimal formation after carotid injury. Phloretin significantly inhibited the PDGF-BB-stimulated RASMC proliferation in a concentration-dependent manner (10-100 μM). Also, PDGF-BB-stimulated RASMC migration was inhibited by phloretin at 50 μM. Pretreating RASMC with phloretin dose-dependently inhibited PDGF-BB-induced Akt and p38 mitogen-activated protein kinases activation. Furthermore, phloretin increased p27 and decreased cyclin-dependent kinase 2, CDK4 expression, and p-Rb activation in PDGF-BB-stimulated RASMC in a concentration-dependent manner (10-50 μM). PDGF-BB-induced cell adhesion molecules and matrix metalloproteinase-9 expression were blocked by phloretin at 50 μM. Preincubation with phloretin dose-dependently reduced the intracellular reactive oxygen species production. In vivo study showed that phloretin (20 mg/kg) significantly reduced neointimal formation 14 days after carotid injury in rats. Thus, phloretin may have potential as a treatment against atherosclerosis and restenosis after vascular injury.

Managing grazing of riparian areas in the Intermountain Region

Treesearch

Warren P. Clary; Bert F. Webster

1989-01-01

Concern about livestock grazing in riparian habitats and its effect upon riparian-dependent resources has resulted in numerous controversies about the appropriate management approach. This document provides guidance for grazing of riparian areas in a manner that should reduce both nonpoint source pollution and potential grazing impacts on other riparian-dependent...

HDAC Inhibition Modulates Hippocampus-Dependent Long-Term Memory for Object Location in a CBP-Dependent Manner

ERIC Educational Resources Information Center

Haettig, Jakob; Stefanko, Daniel P.; Multani, Monica L.; Figueroa, Dario X.; McQuown, Susan C.; Wood, Marcelo A.

2011-01-01

Transcription of genes required for long-term memory not only involves transcription factors, but also enzymatic protein complexes that modify chromatin structure. Chromatin-modifying enzymes, such as the histone acetyltransferase (HAT) CREB (cyclic-AMP response element binding) binding protein (CBP), are pivotal for the transcriptional regulation…

Exogenous fatty acids and niacin on acute prostaglandin D2 production in human myeloid cells.

PubMed

Montserrat-de la Paz, Sergio; Bermudez, Beatriz; Lopez, Sergio; Naranjo, Maria C; Romero, Yolanda; Bando-Hidalgo, Maria J; Abia, Rocio; Muriana, Francisco J G

2017-01-01

Niacin activates HCA 2 receptor that results in the release of PGD 2 . However, little is known on PGD 2 -producing cells and the role of fatty acids. Notably M-CSF macrophages exhibited a timely dependent PGD 2 production upon niacin challenge. Short pretreatment of M-CSF macrophages with autologous postprandial TRLs induced the down-regulation of HCA 2 gene and up-regulation of genes encoding COX1 and COX2 enzymes in a fatty acid-dependent manner. These effects were paralleled by a higher PGD 2 production with postprandial TRL-SFAs. The niacin-mediated transcriptional activity of all genes involved in PGD 2 biosynthesis was desensitized in a time-dependent manner by postprandial TRLs, leading to a decreased PGD 2 release. In vivo, the net excursions of PGD 2 in plasma followed similar fatty acid-dependent patterns as those found for PGD 2 release in vitro. The predominant fatty acid class in the diet acutely modulates PGD 2 biosynthetic pathway both in vitro and in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

Parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner

PubMed Central

2013-01-01

Background It has been suggested that dysfunctional attitudes, cognitive vulnerability to depression, have developmental origins. The present study examined the effects of parental rearing on dysfunctional attitudes in three areas of life with special attention to gender specificity. Methods The subjects were 665 Japanese healthy volunteers. Dysfunctional attitudes were assessed by the 24-item Dysfunctional Attitude Scale, which has the Achievement, Dependency and Self-control subscales. Perceived parental rearing was assessed by the Parental Bonding Instrument, which has the Care and Protection subscales. Results Higher scores of the Achievement (β = 0.293, p < 0.01) and Dependency (β = 0.224, p < 0.05) subscales were correlated with higher scores of the Protection subscale in the combination of mother and daughter, but not in other combinations of parents and recipients. Scores of the Self-control subscale were not correlated with paternal or maternal rearing scores. Conclusions The present study suggests that parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner. PMID:24365104

3-D model-based Bayesian classification

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

Soenneland, L.; Tenneboe, P.; Gehrmann, T.

1994-12-31

The challenging task of the interpreter is to integrate different pieces of information and combine them into an earth model. The sophistication level of this earth model might vary from the simplest geometrical description to the most complex set of reservoir parameters related to the geometrical description. Obviously the sophistication level also depend on the completeness of the available information. The authors describe the interpreter`s task as a mapping between the observation space and the model space. The information available to the interpreter exists in observation space and the task is to infer a model in model-space. It is well-knownmore » that this inversion problem is non-unique. Therefore any attempt to find a solution depend son constraints being added in some manner. The solution will obviously depend on which constraints are introduced and it would be desirable to allow the interpreter to modify the constraints in a problem-dependent manner. They will present a probabilistic framework that gives the interpreter the tools to integrate the different types of information and produce constrained solutions. The constraints can be adapted to the problem at hand.« less

Spermidine promotes stress resistance in Drosophila melanogaster through autophagy-dependent and -independent pathways.

PubMed

Minois, N; Carmona-Gutierrez, D; Bauer, M A; Rockenfeller, P; Eisenberg, T; Brandhorst, S; Sigrist, S J; Kroemer, G; Madeo, F

2012-10-11

The naturally occurring polyamine spermidine (Spd) has recently been shown to promote longevity across species in an autophagy-dependent manner. Here, we demonstrate that Spd improves both survival and locomotor activity of the fruit fly Drosophila melanogaster upon exposure to the superoxide generator and neurotoxic agent paraquat. Although survival to a high paraquat concentration (20 mM) was specifically increased in female flies only, locomotor activity and survival could be rescued in both male and female animals when exposed to lower paraquat levels (5 mM). These effects are dependent on the autophagic machinery, as Spd failed to confer resistance to paraquat-induced toxicity and locomotor impairment in flies deleted for the essential autophagic regulator ATG7 (autophagy-related gene 7). Spd treatment did also protect against mild doses of another oxidative stressor, hydrogen peroxide, but in this case in an autophagy-independent manner. Altogether, this study establishes that the protective effects of Spd can be exerted through different pathways that depending on the oxidative stress scenario do or do not involve autophagy.

Dengue Virus Modulates the Unfolded Protein Response in a Time-dependent Manner*

PubMed Central

Peña, José; Harris, Eva

2011-01-01

Flaviviruses, such as dengue virus (DENV), depend on the host endoplasmic reticulum for translation, replication, and packaging of their genomes. Here we report that DENV-2 infection modulates the unfolded protein response in a time-dependent manner. We show that early DENV-2 infection triggers and then suppresses PERK-mediated eIF2α phosphorylation and that in mid and late DENV-2 infection, the IRE1-XBP1 and ATF6 pathways are activated, respectively. Activation of IRE1-XBP1 correlated with induction of downstream targets GRP78, CHOP, and GADD34. Furthermore, induction of CHOP did not induce apoptotic markers, such as suppression of anti-apoptotic protein Bcl-2, activation of caspase-9 or caspase-3, and cleavage of poly(ADP-ribose) polymerase. Finally, we show that DENV-2 replication is affected in PERK−/− and IRE1−/− mouse embryo fibroblasts when compared with wild-type mouse embryo fibroblasts. These results demonstrate that time-dependent activation of the unfolded protein response by DENV-2 can override inhibition of translation, prevent apoptosis, and prolong the viral life cycle. PMID:21385877

Single-residue molecular switch for high-temperature dependence of vanilloid receptor TRPV3

PubMed Central

Liu, Beiying; Qin, Feng

2017-01-01

Thermal transient receptor potential (TRP) channels, a group of ion channels from the transient receptor potential family, play important functions in pain and thermal sensation. These channels are directly activated by temperature and possess strong temperature dependence. Furthermore, their temperature sensitivity can be highly dynamic and use-dependent. For example, the vanilloid receptor transient receptor potential 3 (TRPV3), which has been implicated as a warmth detector, becomes responsive to warm temperatures only after intensive stimulation. Upon initial activation, the channel exhibits a high-temperature threshold in the noxious temperature range above 50 °C. This use dependence of heat sensitivity thus provides a mechanism for sensitization of thermal channels. However, how the channels acquire the use dependence remains unknown. Here, by comparative studies of chimeric channels between use-dependent and use-independent homologs, we have determined the molecular basis that underlies the use dependence of temperature sensitivity of TRPV3. Remarkably, the restoration of a single residue that is apparently missing in the use-dependent homologs could largely eliminate the use dependence of heat sensitivity of TRPV3. The location of the region suggests a mechanism of temperature-dependent gating of thermal TRP channels involving an intracellular region assembled around the TRP domain. PMID:28154143

Fluidized Bed Boiler Assessment for Navy Applications

DTIC Science & Technology

1986-11-01

rather than removing it from the flue gas later with "scrubbing" devices. Intro- duction of limestone in the bed will reduce SO emissions; two...boiler in a satisfactory manner, the bed level, combustion temperature, and the flue gas composition and temperature should be continuously monitored...The flue gas composition should be c^-ɝely monitored for pollutants and combustion efficiency. EVOLUTION OF FBC BOILERS The performance of FBC

Molecular Simulation Studies of Covalently and Ionically Grafted Nanoparticles

NASA Astrophysics Data System (ADS)

Hong, Bingbing

Solvent-free covalently- or ionically-grafted nanoparticles (CGNs and IGNs) are a new class of organic-inorganic hybrid composite materials exhibiting fluid-like behaviors around room temperature. With similar structures to prior systems, e.g. nanocomposites, neutral or charged colloids, ionic liquids, etc, CGNs and IGNs inherit the functionality of inorganic nanopariticles, the facile processibility of polymers, as well as conductivity and nonvolatility from their constituent materials. In spite of the extensive prior experimental research having covered synthesis and measurements of thermal and dynamic properties, little progress in understanding of these new materials at the molecular level has been achieved, because of the lack of simulation work in this new area. Atomistic and coarse-grained molecular dynamics simulations have been performed in this thesis to investigate the thermodynamics, structure, and dynamics of these systems and to seek predictive methods predictable for their properties. Starting from poly(ethylene oxide) oligomers (PEO) melts, we established atomistic models based on united-atom representations of methylene. The Green-Kubo and Einstein-Helfand formulas were used to calculate the transport properties. The simulations generate densities, viscosities, diffusivities, in good agreement with experimental data. The chain-length dependence of the transport properties suggests that neither Rouse nor reptation models are applicable in the short-chain regime investigated. Coupled with thermodynamic integration methods, the models give good predictions of pressure-composition-density relations for CO 2 + PEO oligomers. Water effects on the Henry's constant of CO 2 in PEO have also been investigated. The dependence of the calculated Henry's constants on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length. CGNs are modeled by the inclusion of solid-sphere nanoparticles into the atomistic oligomers. The calculated viscosities from Green-Kubo relationships and temperature extrapolation are of the same order of magnitude as experimental values, but show a smaller activation energy relative to real CGNs systems. Grafted systems have higher viscosities, smaller diffusion coefficients, and slower chain dynamics than the ungrafted counterparts - nanocomposites - at high temperatures. At lower temperatures, grafted systems exhibit faster dynamics for both nanoparticles and chains relative to ungrafted systems, because of lower aggregation of nanoparticles and enhanced correlations between nanoparticles and chains. This agrees with the experimental observation that the new materials have liquid-like behavior in the absence of a solvent. To lower the simulated temperatures into the experimental range, we established a coarse-grained CGNs model by matching structural distribution functions to atomistic simulation data. In contrast with linear polymer systems, for which coarse-graining always accelerate dynamics, coarse-graining of grafted nanoparticles can either accelerate or slowdown the core motions, depending on the length of the grafted chains. This can be qualitatively predicted by a simple transition-state theory. Similar atomistic models to CGNs were developed for IGNs, with ammonium counterions described by an explicit-hydrogen way; these were in turn compared with "generic" coarse-grained IGNs. The elimination of chemical details in the coarse-grained models does not bring in qualitative changes to the radial distribution functions and diffusion of atomistic IGNs, but saves considerable simulation resources and make simulations near room temperatures affordable. The chain counterions in both atomistic and coarse-grained models are mobile, moving from site to site and from nanoparticle to nanoparticle. At the same temperature and the same core volume fractions, the nanoparticle diffusivities in coarse-grained IGNs are slower by a factor ten than the cores of CGNs. The coarse-grained IGNs models are later used to investigate the system dynamics through analysis of the dependence on temperature and structural parameters of the transport properties (self-diffusion coefficients, viscosities and conductivities). Further, migration kinetics of oligomeric counterions is analyzed in a manner analogous to unimer exchange between micellar aggregates. The counterion migrations follow the "double-core" mechanism and are kinetically controlled by neighboring-core collisions. (Abstract shortened by UMI.)

Adenosine triphosphate regulates the activity of guinea pig Cav1.2 channel by direct binding to the channel in a dose-dependent manner.

PubMed

Feng, Rui; Xu, Jianjun; Minobe, Etsuko; Kameyama, Asako; Yang, Lei; Yu, Lifeng; Hao, Liying; Kameyama, Masaki

2014-05-01

The present study is to investigate the mechanism by which ATP regulates Cav1.2 channel activity. Ventricular tissue was obtained from adult guinea pig hearts using collagenase. Ca(2+) channel activity was monitored using the patch-clamp technique. Proteins were purified using wheat germ agglutinin-Sepharose, and the concentration was determined using the Coomassie brilliant blue technique. ATP binding to the Cav1.2 channel was examined using the photoaffinity method. EDA-ATP-biotin maintains Ca(2+) channel activity in inside-out membrane patches. ATP directly bound to the Cav1.2 channel in a dose-dependent manner, and at least two molecules of ATP bound to one molecule of the Cav1.2 channel. Low levels of calmodulin (CaM) increased ATP binding to the Cav1.2 channel, but higher levels of CaM decreased ATP binding to the Cav1.2 channel. In addition, Ca(2+) was another regulator for ATP binding to the Cav1.2 channel. Furthermore, ATP bound to GST-fusion peptides of NH2-terminal region (amino acids 6-140) and proximal COOH-terminal region (amino acids 1,509-1,789) of the main subunit (α1C) of the Cav1.2 channel. Our data suggest that ATP might regulate Cav1.2 channel activity by directly binding to the Cav1.2 channel in a dose-dependent manner. In addition, the ATP-binding effect to the Cav1.2 channel was both CaM- and Ca(2+) dependent.

The Development of a Viral Mediated CRISPR/Cas9 System with Doxycycline Dependent gRNA Expression for Inducible In vitro and In vivo Genome Editing

PubMed Central

de Solis, Christopher A.; Ho, Anthony; Holehonnur, Roopashri; Ploski, Jonathan E.

2016-01-01

The RNA-guided Cas9 nuclease, from the type II prokaryotic Clustered Regularly Interspersed Short Palindromic Repeats (CRISPR) adaptive immune system, has been adapted and utilized by scientists to edit the genomes of eukaryotic cells. Here, we report the development of a viral mediated CRISPR/Cas9 system that can be rendered inducible utilizing doxycycline (Dox) and can be delivered to cells in vitro and in vivo utilizing adeno-associated virus (AAV). Specifically, we developed an inducible gRNA (gRNAi) AAV vector that is designed to express the gRNA from a H1/TO promoter. This AAV vector is also designed to express the Tet repressor (TetR) to regulate the expression of the gRNAi in a Dox dependent manner. We show that H1/TO promoters of varying length and a U6/TO promoter can edit DNA with similar efficiency in vitro, in a Dox dependent manner. We also demonstrate that our inducible gRNAi vector can be used to edit the genomes of neurons in vivo within the mouse brain in a Dox dependent manner. Genome editing can be induced in vivo with this system by supplying animals Dox containing food for as little as 1 day. This system might be cross compatible with many existing S. pyogenes Cas9 systems (i.e., Cas9 mouse, CRISPRi, etc.), and therefore it likely can be used to render these systems inducible as well. PMID:27587996

Efficacy and safety of tranexamic acid as an emetic in dogs.

PubMed

Kakiuchi, Hitoshi; Kawarai-Shimamura, Asako; Fujii, Yoko; Aoki, Takuma; Yoshiike, Masaki; Arai, Hayato; Nakamura, Atsushi; Orito, Kensuke

2014-12-01

To determine dose dependency of tranexamic acid-induced emesis and the time course of the antifibrinolytic potency of tranexamic acid in dogs. 10 Beagles. In a dose-escalating experiment, ascending doses of tranexamic acid (10, 20, and 30 mg/kg, IV) were administered at 5-minute intervals until vomiting was observed. In a separate single-dose experiment, ascending doses of tranexamic acid (20, 30, 40, and 50 mg/kg, IV) were administered at 1-week intervals until vomiting was observed. Time to onset of vomiting and number of vomiting episodes were measured in both experiments. In a coagulation experiment, a single 50 mg/kg bolus of tranexamic acid was administered, and blood was obtained 1 hour before and 20 minutes, 3 hours, and 24 hours after administration. Antifibrinolytic potency of tranexamic acid was evaluated by use of a modified rotational thromboelastography method. Tranexamic acid induced vomiting in a dose-dependent manner. Vomiting frequency was ≤ 2 episodes, and vomiting concluded ≤ 250 seconds after administration. Antifibrinolytic potency of tranexamic acid was significantly higher at 20 minutes following administration, but not different by 24 hours, when compared with the potency measured before administration. No adverse effects were observed in any experiment. IV administration of tranexamic acid induced emesis in a dose-dependent manner. The antifibrinolytic potency of tranexamic acid decreased in a time-dependent manner and was resolved ≤ 24 hours after administration. Further studies are warranted to investigate the emetic and other adverse effects of tranexamic acid in dogs of various breeds and ages.

Impact Properties at Different Temperatures of Flush-Riveted Joints for Aircraft Manufactured by Various Riveting Methods

DTIC Science & Technology

1945-09-01

available. Also, very little work appears to have been reported on the effect of heat treatment on the lowt* HACA ABB Ho. 6T07 13 temperature impact...rivets in 24S-T aluminum-alloy sheet. II. Treatment . The 8amples were mounted and ground and polished in the usual manner. Etching was done by...had been subjected to the low temperature 16 NACA ABB So. 6T07 treatment , and this hold for the specimens which had been at 70° 7 for 38 hours after

[Effect of chloride ion on corrosion of two commonly used dental alloys].

PubMed

Chen, Lei; Zhang, Weidan; Zhang, Yuanyuan

2014-11-01

To investigate the eff ect of chloride concentration on the corrosion of Co-Cr alloy and pure Ti in a simulated oral environment. The electrochemical corrosion tests of pure Ti and Co-Cr alloy were carried out in neutral artificial saliva solutions with different NaCl concentrations (0.9%, 2.0%, and 3.0%). Th e morphologies of corroded surface for pure Ti and Co-Cr alloy were observed by scanning electron microscope (SEM). Th e changes in the self-corrosion potentials (Ecorr) for pure Ti and Co-Cr alloy in three kinds of artificial saliva solutions was not obvious. However, the self-corrosion current densities (Icorr) of pure Ti were much lower than those of Co-Cr. The Icorr of Co-Cr alloy increased in a concentration-dependent manner of NaCl, whereas the breakdown potential (Eb) of Co-Cr alloy decreased in a concentration-dependent manner. Th e potential ranged for the breakdown of oxide film (Ev) was shortened in a concentration-dependent manner of NaCl. There was no obvious difference in the Icorr of pure Ti with different concentrations of NaCl. The breakdown potential was not seen according to the polarization curves. In a certain range, the increase of the concentration of Cl- leads to accelerate the corrosion behavior of Co-Cr alloy, but it does not affect pure Ti.

Aldosterone concentrations in saliva reflect the duration and severity of depressive episode in a sex dependent manner.

PubMed

Segeda, V; Izakova, L; Hlavacova, N; Bednarova, A; Jezova, D

2017-08-01

Evidence is accumulating that aldosterone may exert central actions and influence mental functions. The aim of the present study was to test the hypothesis that major depressive disorder affects the diurnal variation of salivary aldosterone and that aldosterone concentrations reflect the duration and severity of the depressive episode in a sex dependent manner. The sample consisted of 60 patients (37 postmenopausal women, 23 men) with major depressive disorder. Patients were examined two times, in acute depressive episode (admission to the hospital) and after reaching clinical remission (discharge). The samples of saliva were taken by the patients themselves twice a day (8.00-9.00 h in the morning and in the evening). Aldosterone concentrations were significantly higher in women compared to men and were significantly higher at the time of admission to the hospital compared to those at the discharge. Morning but not evening salivary aldosterone concentrations reflected the length of the depressive episode in women as well as the severity of the disorder in both sexes. Moreover, the patients with depression failed to exert known daily rhythmicity of aldosterone release. The present study brings several pieces of evidence suggesting the association of aldosterone with the pathophysiology of depression. Salivary aldosterone concentrations appear to reflect the outcome, the duration and the severity of the depressive episode in a sex dependent manner. Copyright © 2017 Elsevier Ltd. All rights reserved.

Calcium signals and caspase-12 participated in paraoxon-induced apoptosis in EL4 cells.

PubMed

Li, Lan; Cao, Zhiheng; Jia, Pengfei; Wang, Ziren

2010-04-01

In order to investigate whether calcium signals participate in paraoxon (POX)-induced apoptosis in EL4 cells, real-time laser scanning confocal microscopy (LSCM) was used to detect Ca(2+) changes during the POX application. Apoptotic rates of EL4 cells and caspase-12 expression were also evaluated. POX (1-10nM) increased intracellular calcium concentration ([Ca(2+)]i) in EL4 cells in a dose-dependent manner at early stage (0-2h) of POX application, and apoptotic rates of EL4 cells after treatment with POX for 16h were also increased in a dose-dependent manner. Pre-treatment with EGTA, heparin or procaine attenuated POX-induced [Ca(2+)]i elevation and apoptosis. Additionally, POX up-regulated caspase-12 expression in a dose-dependent manner, and pre-treatment with EGTA, heparin or procaine significantly inhibited POX-induced increase of caspase-12 expression. Our results suggested that POX induced [Ca(2+)]i elevation in EL4 cells at the early stage of POX-induced apoptosis, which might involve Ca(2+) efflux from the endoplasmic reticulum (ER) and Ca(2+) influx from extracellular medium. Calcium signals and caspase-12 were important upstream messengers in POX-induced apoptosis in EL4 cells. The ER-associated pathway possibly operated in this apoptosis. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Hedonic sensitivity to low-dose ketamine is modulated by gonadal hormones in a sex-dependent manner

PubMed Central

Saland, Samantha K.; Schoepfer, Kristin J.; Kabbaj, Mohamed

2016-01-01

We recently reported a greater sensitivity of female rats to rapid antidepressant-like effects of ketamine compared to male rats, and that ovarian-derived estradiol (E2) and progesterone (P4) are essential for this response. However, to what extent testosterone may also contribute, and whether duration of response to ketamine is modulated in a sex- and hormone-dependent manner remains unclear. To explore this, we systematically investigated the influence of testosterone, estradiol and progesterone on initiation and maintenance of hedonic response to low-dose ketamine (2.5 mg/kg) in intact and gonadectomized male and female rats. Ketamine induced a sustained increase in sucrose preference of female, but not male, rats in an E2P4-dependent manner. Whereas testosterone failed to alter male treatment response, concurrent administration of P4 alone in intact males enhanced hedonic response low-dose ketamine. Treatment responsiveness in female rats only was associated with greater hippocampal BDNF levels, but not activation of key downstream signaling effectors. We provide novel evidence supporting activational roles for ovarian-, but not testicular-, derived hormones in mediating hedonic sensitivity to low-dose ketamine in female and male rats, respectively. Organizational differences may, in part, account for the persistence of sex differences following gonadectomy and selective involvement of BDNF in treatment response. PMID:26888470

Oxytocin prevents cartilage matrix destruction via regulating matrix metalloproteinases.

PubMed

Wu, Yixin; Wu, Tongyu; Xu, Binbin; Xu, Xiaoyan; Chen, Honggan; Li, Xiyao

2017-05-06

Degradation of the extracellular matrix type II Collagen (Col II) induced by proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) is an important hallmark of Osteoarthritis (OA). Oxytocin (OT) is a well-known neurohypophysical hormone that is synthesized in the paraventricular (PVN) and supraoptic nuclei (SON) of the hypothalamus. In this study, we have found that oxytocin receptor (OTR) was expressed in human primary chondrocytes, and the expression of which was reduced in chondrocytes from OA patients and in response to TNF-α treatment in a dose dependent manner. Notably, it was shown that TNF-α -induced degradation of Col II was restored by treatment with OT in a dose-dependent manner. In addition, TNF-α treatment (10 ng/mL) highly elevated the expression of MMP-1 and MMP-13 in SW1353 chondrocytes, which were reversed by OT in a dose dependent manner at both gene and protein expression levels. In addition, it was demonstrated that the JAK2/STAT1 pathway was involved in the restoration effects of OT in the degradation of Col II. Lastly, knockdown of OTR abolished the inhibitory effects of OT on the degradation of col II and the induction of MMP-1 and MMP-13 expression, suggesting the involvement of OTR. Our study implied the therapeutic potential of OT for cartilage degradation. Copyright © 2017 Elsevier Inc. All rights reserved.

Neuron-derived orphan receptor 1 promoted human pulmonary artery smooth muscle cells proliferation.

PubMed

Wang, Chang-Guo; Lei, Wei; Li, Chang; Zeng, Da-Xiong; Huang, Jian-An

2015-05-01

As a transcription factor of the nuclear receptor superfamily, neuron-derived orphan receptor 1 (NOR1) is induced rapidly in response to various extracellular stimuli. But, it is still unclear its role in pulmonary artery smooth muscle cells proliferation. Human PASMCs were cultured in vitro and stimulated by serum. The special antisense oligodeoxynucleotides (AS-ODNs) were used to knockdown human NOR1 gene expression. Real-time PCR and Western-blot were used to evaluate the gene expression and protein levels. Fetal bovine serum (FBS) induced human PASMCs proliferation in a dose dependent manner. Furthermore, FBS promoted NOR1 gene expression in a dose dependent manner and a time dependent manner. 10% FBS induced a maximal NOR1 mRNA levels at 2 h. FBS also induced a significant higher NOR1 protein levels as compared with control. The NOR1 over-expressed plasmid significantly promoted DNA synthesis and cells proliferation. Moreover, the special AS-ODNs against human NOR1 not only prevented NOR1 expression but also inhibited DNA synthesis and cells proliferation significantly. The NOR1 over-expression plasmid could up-regulate cyclin D1 expression markedly, but the AS-ODNs inhibited cyclin D1 expression significantly. So, we concluded that NOR1 could promote human PASMCs proliferation. Cyclin D1 might be involved in this process.

Effect of tributyltin on testicular development in Sebastiscus marmoratus and the mechanism involved.

PubMed

Zhang, Jiliang; Zuo, Zhenghong; He, Chengyong; Cai, Jiali; Wang, Yuqing; Chen, Yixin; Wang, Chonggang

2009-07-01

Organotin compounds, such as tributyltin (TBT), that have been used as antifouling biocides can induce masculinization in female mollusks. However, few studies addressing the effects of TBT on fishes have been reported. The present study was conducted to investigate the effects of TBT at environmentally relevant concentrations (1, 10, and 100 ng/L) on testicular development in Sebastiscus marmoratus and to gain insight into its mechanism of action. After exposure for 48 d, the gonadosomatic index had decreased in a dose-dependent manner. Although the testosterone levels in the testes were elevated and the 17beta-estradiol levels were decreased, spermatogenesis was suppressed. Moreover, gamma-glutamyl transpeptidase activity (which is used as a Sertoli cell marker) was decreased in a dose-dependent manner after TBT exposure, and serious interstitial fibrosis was observed in the interlobular septa of the testes in the 100 ng/L TBT test group. Increases in the retinoid X receptors and peroxisome proliferator activated receptor gamma expression and the progressive enlargement of lipid droplets in the testes were observed after TBT exposure. Estrogen receptor alpha levels in the testes of the fish exposed to TBT decreased in a dose-dependent manner. The reduction of estrogen receptor alpha mRNA resulted from the decrease of 17beta-estradiol levels, and the progressive enlargement of lipid droplets may have contributed to the dysfunction of the Sertoli cells, which then disrupted spermatogenesis.

Oxymatrine inhibits the proliferation of prostate cancer cells in vitro and in vivo

PubMed Central

WU, CUNZAO; HUANG, WEIPING; GUO, YONG; XIA, PENG; SUN, XIANBIN; PAN, XIAODONG; HU, WEILIE

2015-01-01

Oxymatrine is an alkaloid, which is derived from the traditional Chinese herb, Sophora flavescens Aiton. Oxymatrine has been shown to exhibit anti-inflammatory, antiviral, and anticancer properties. The present study aimed to investigate the anticancer effects of oxymatrine in human prostate cancer cells, and the underlying molecular mechanisms of these effects. An MTT assay demonstrated that oxymatrine significantly inhibited the proliferation of prostate cancer cells in a time- and dose-dependent manner. In addition, flow cytometry and a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling assay suggested that oxymatrine treatment may induce prostate cancer cell apoptosis in a dose-dependent manner. Furthermore, western blot analysis demonstrated a significant increase in the expression of p53 and bax, and a significant decrease in that of Bcl-2, in prostrate cancer cells in a dose-dependent manner. In vivo analysis demonstrated that oxymatrine inhibited tumor growth following subcutaneous inoculation of prostate cancer cells into nude mice. The results of the present study suggested that the antitumor properties of oxymatrine, may be associated with the inhibition of cell proliferation, and induction of apoptosis, via the regulation of apoptosis-associated gene expression. Therefore, the results may provide a novel approach for the development of prostate cancer therapy using oxymatrine, which is derived from the traditional Chinese herb, Sophora flavescens. PMID:25672672

Phenformin activates the unfolded protein response in an AMP-activated protein kinase (AMPK)-dependent manner.

PubMed

Yang, Liu; Sha, Haibo; Davisson, Robin L; Qi, Ling

2013-05-10

The cross-talk between UPR activation and metabolic stress remains largely unclear. Phenformin treatment activates the IRE1α and PERK pathways in an AMPK-dependent manner. AMPK is required for phenformin-mediated IRE1α and PERK activation. Our findings demonstrate the cross-talk between UPR and metabolic signals. Activation of the unfolded protein response (UPR) is associated with the disruption of endoplasmic reticulum (ER) homeostasis and has been implicated in the pathogenesis of many human metabolic diseases, including obesity and type 2 diabetes. However, the nature of the signals activating UPR under these conditions remains largely unknown. Using a method that we recently optimized to directly measure UPR sensor activation, we screened the effect of various metabolic drugs on UPR activation and show that the anti-diabetic drug phenformin activates UPR sensors IRE1α and pancreatic endoplasmic reticulum kinase (PERK) in both an ER-dependent and ER-independent manner. Mechanistically, AMP-activated protein kinase (AMPK) activation is required but not sufficient to initiate phenformin-mediated IRE1α and PERK activation, suggesting the involvement of additional factor(s). Interestingly, activation of the IRE1α (but not PERK) pathway is partially responsible for the cytotoxic effect of phenformin. Together, our data show the existence of a non-canonical UPR whose activation requires the cytosolic kinase AMPK, adding another layer of complexity to UPR activation upon metabolic stress.

[Effects of sinensetin on proliferation and apoptosis of human gastric cancer AGS cells].

PubMed

Dong, Yang; Ji, Guang; Cao, Aili; Shi, Jianrong; Shi, Hailian; Xie, Jianqun; Wu, Dazheng

2011-03-01

To study the effects and mechanisms of sinensetin on proliferation and apoptosis of human AGS gastric cancer cells. MTT assay was used to detect the growth inhibition rates of human AGS gastric cancer cells treated with sinsesectin in different concentrations and times. The cell cycle distribution was measured by flow cytometry. The apoptosis was examined by Annexin-FITC/PI staining and DNA fragment analysis. The apoptosis morphology was observed by inverted fluorescence microscope after Hoechst 33342 staining. The protein expressions of p21 and p53 were detected by western blot. MTT assay showed that sinensetin inhibited the growth of AGS gastric cancer cells in a dose- and time-dependent manner. Sinensetin blocked AGS cells in G2/ M and increased the apoptosis rates of AGS cells in a dose-dependent manner. DNA ladder was observed in cells treated with 60 micromol x L(-1) sinensetin for 48 h. The typical apoptotic morphological changes including cell nucleus shrinkage, chromatin condensation and apoptotic bodies were observed when treated with different dose of sinensetin. Western blot showed that sinensetin increased expressions of p53 and p21 in a dose-dependent manner. Sinensetin could inhibit human AGS gastric cancer cells proliferation and induce cell cycle block in G2/M phase and apoptosis. The up regulation of p53 and p21 protein might be one of the mechanisms.

Dexamethasone Enhances 1α,25-Dihydroxyvitamin D3 Effects by Increasing Vitamin D Receptor Transcription*

PubMed Central

Hidalgo, Alejandro A.; Deeb, Kristin K.; Pike, J. Wesley; Johnson, Candace S.; Trump, Donald L.

2011-01-01

Calcitriol, the active form of vitamin D, in combination with the glucocorticoid dexamethasone (Dex) has been shown to increase the antitumor effects of calcitriol in squamous cell carcinoma. In this study we found that pretreatment with Dex potentiates calcitriol effects by inhibiting cell growth and increasing vitamin D receptor (VDR) and VDR-mediated transcription. Treatment with actinomycin D inhibits Vdr mRNA synthesis, indicating that Dex regulates VDR expression at transcriptional level. Real time PCR shows that treatment with Dex increases Vdr transcripts in a time- and a dose-dependent manner, indicating that Dex directly regulates expression of Vdr. RU486, an inhibitor of glucocorticoids, inhibits Dex-induced Vdr expression. In addition, the silencing of glucocorticoid receptor (GR) abolishes the induction of Vdr by Dex, indicating that Dex increases Vdr transcripts in a GR-dependent manner. A fragment located 5.2 kb upstream of Vdr transcription start site containing two putative glucocorticoid response elements (GREs) was evaluated using a luciferase-based reporter assay. Treatment with 100 nm Dex induces transcription of luciferase driven by the fragment. Deletion of the GRE distal to transcription start site was sufficient to abolish Dex induction of luciferase. Also, chromatin immunoprecipitation reveals recruitment of GR to distal GRE with Dex treatment. We conclude that Dex increases VDR and vitamin D effects by increasing Vdr de novo transcription in a GR-dependent manner. PMID:21868377

Transformation process for production of ultrahigh carbon steels and new alloys

DOEpatents

Strum, M.J.; Goldberg, A.; Sherby, O.D.; Landingham, R.L.

1995-08-29

Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50 C above the A{sub 1} transformation temperature, soaking the steel above the A{sub 1} temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature. 9 figs.

Transformation process for production of ultrahigh carbon steels and new alloys

DOEpatents

Strum, Michael J.; Goldberg, Alfred; Sherby, Oleg D.; Landingham, Richard L.

1995-01-01

Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50.degree. C. above the A.sub.1 transformation temperature, soaking the steel above the A.sub.1 temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature.

Mechanical Properties of LaRC(tm) SI Polymer for a Range of Molecular Weights

NASA Technical Reports Server (NTRS)

Whitley, Karen S.; Gates, Thomas S.; Hinkley, Jeffrey A.; Nicholson, Lee M.

2000-01-01

Mechanical testing of an advanced polyimide resin (LaRC(tm)-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. Elastic and inelastic properties were characterized as a function of molecular weight and test temperature. It was shown that notched tensile strength is a strong function of both temperature and molecular weight, whereas stiffness is only a strong function of temperature. The combined analysis of calculated yield stress and notched tensile strength indicated that low molecular weight materials tended to fail in a brittle manner, whereas high molecular weight materials exhibited ductile failure. The microphotographs of the failure surfaces also supported these findings.

Social defeat promotes a reactive endothelium in a brain region-dependent manner with increased expression of key adhesion molecules, selectins and chemokines associated with the recruitment of myeloid cells to the brain.

PubMed

Sawicki, C M; McKim, D B; Wohleb, E S; Jarrett, B L; Reader, B F; Norden, D M; Godbout, J P; Sheridan, J F

2015-08-27

Repeated social defeat (RSD) in mice causes myeloid cell trafficking to the brain that contributes to the development of prolonged anxiety-like behavior. Myeloid cell recruitment following RSD occurs in regions where neuronal and microglia activation is observed. Thus, we hypothesized that crosstalk between neurons, microglia, and endothelial cells contributes to brain myeloid cell trafficking via chemokine signaling and vascular adhesion molecules. Here we show that social defeat caused an exposure- and brain region-dependent increase in several key adhesion molecules and chemokines involved in the recruitment of myeloid cells. For example, RSD induced distinct patterns of adhesion molecule expression that may explain brain region-dependent myeloid cell trafficking. VCAM-1 and ICAM-1 mRNA expression were increased in an exposure-dependent manner. Furthermore, RSD-induced VCAM-1 and ICAM-1 protein expression were localized to the vasculature of brain regions implicated in fear and anxiety responses, which spatially corresponded to previously reported patterns of myeloid cell trafficking. Next, mRNA expression of additional adhesion molecules (E- and P-selectin, PECAM-1) and chemokines (CXCL1, CXCL2, CXCL12, CCL2) were determined in the brain. Social defeat induced an exposure-dependent increase in mRNA levels of E-selectin, CXCL1, and CXCL2 that increased with additional days of social defeat. While CXCL12 was unaffected by RSD, CCL2 expression was increased by six days of social defeat. Last, comparison between enriched CD11b(+) cells (microglia/macrophages) and enriched GLAST-1(+)/CD11b(-) cells (astrocytes) revealed RSD increased mRNA expression of IL-1β, CCL2, and CXCL2 in microglia/macrophages but not in astrocytes. Collectively, these data indicate that key mediators of leukocyte recruitment were increased in the brain vasculature following RSD in an exposure- and brain region-dependent manner. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Social defeat promotes a reactive endothelium in a brain region-dependent manner with increased expression of key adhesion molecules, selectins and chemokines associated with the recruitment of myeloid cells to the brain

PubMed Central

Sawicki, Caroline M.; McKim, Daniel B.; Wohleb, Eric S.; Jarrett, Brant L.; Reader, Brenda F.; Norden, Diana M.; Godbout, Jonathan P.; Sheridan, John F.

2014-01-01

Repeated social defeat (RSD) in mice causes myeloid cell trafficking to the brain that contributes to the development of prolonged anxiety-like behavior. Myeloid cell recruitment following RSD occurs in regions where neuronal and microglia activation is observed. Thus, we hypothesized that crosstalk between neurons, microglia, and endothelial cells contributes to brain-myeloid cell trafficking via chemokine signaling and vascular adhesion molecules. Here we show that social defeat caused an exposure- and brain region-dependent increase in several key adhesion molecules and chemokines involved in the recruitment of myeloid cells. For example, RSD induced distinct patterns of adhesion molecule expression that may explain brain region-dependent myeloid cell trafficking. VCAM-1 and ICAM-1 mRNA expression were increased in an exposure-dependent manner. Furthermore, RSD-induced VCAM-1 and ICAM-1 protein expression were localized to the vasculature of brain regions implicated in fear and anxiety responses, which spatially corresponded to previously reported patterns of myeloid cell trafficking. Next, mRNA expression of additional adhesion molecules (E- and P-selectin, PECAM-1) and chemokines (CXCL1, CXCL2, CXCL12, CCL2) were determined in the brain. Social defeat induced an exposure-dependent increase in mRNA levels of E-selectin, CXCL1, and CXCL2 that increased with additional days of social defeat. While CXCL12 was unaffected by RSD, CCL2 expression was increased by six days of social defeat. Last, comparison between enriched CD11b+ cells (microglia/macrophages) and enriched GLAST-1+/CD11b− cells (astrocytes) revealed RSD increased mRNA expression of IL-1β, CCL2, and CXCL2 in microglia/macrophages but not in astrocytes. Collectively, these data indicate that key mediators of leukocyte recruitment were increased in the brain vasculature following RSD in an exposure- and brain-region dependent manner. PMID:25445193

Temperature effect on refractive index sensing performance of a U-shape tapered plastic optical fiber

NASA Astrophysics Data System (ADS)

Teng, Chuanxin; Yu, Fangda; Jing, Ning; Zheng, Jie

2016-11-01

The temperature dependence of a refractive index (RI) sensing probe based on a U-shape tapered plastic optical fiber (POF) was investigated experimentally. The changes in light propagation loss in the probe induced by temperature are of the same order of magnitude as those induced by measured RI changes. The temperature dependence loss and temperature dependence RI deviation of the sensing probe were measured (at the wavelength of 635 nm) in temperature of 10-60 °C. By extracting pure temperature dependence of the sensing probe alone, the influence of temperature to the sensor was characterized.

The influence of temperature to a refractive index sensor based on a macro-bending tapered plastic optical fiber

NASA Astrophysics Data System (ADS)

Teng, Chuan-xin; Yu, Fang-da; Jing, Ning; Zheng, Jie

2016-09-01

The temperature influence to a refractive index (RI) sensor based on a macro-bending tapered plastic optical fiber (POF) was investigated experimentally. The total temperature dependence loss (TDLtotal) and total temperature dependence RI deviation (TDRtotal) were measured at different temperature (10-60 °C) over an RI range of 1.33-1.41. The temperature dependence RI deviation of the sensor itself was obtained by subtracting the temperature dependence RI of measured liquid from TDRtotal. Therefore, the influence of temperature variation to the sensor was characterized and corrected.

Application of continuous monitoring of honeybee colonies

USDA-ARS?s Scientific Manuscript database

Monitoring physical variables associated with honey bee colonies, including weight, temperature, humidity, respiratory gases, vibration, acoustics and forager traffic, in a continuous manner is becoming feasible for most researchers as the cost and size of electronic sensors and dataloggers decrease...

Ferrihydrite Alteration to Magnetite, Maghemite and Hematite; Implications for Iron Oxides on Mars

NASA Technical Reports Server (NTRS)

Zent, A. P.; Bishop, J. L.; Mancinelli, R. L.; Olsen, M.; Wagner, P. A.

2000-01-01

Synthetic ferrihydrites have been altered to form magnetite, maghemite and hematite through low-temperature heating experiments (some with an organic reductant). Maghemite formed in this manner could become an indicator for Astrobiology on Mars.

Polycrystalline elastic moduli of a high-entropy alloy at cryogenic temperatures

DOE PAGES

Haglund, A.; Koehler, M.; Catoor, D.; ...

2014-12-05

A FCC high-entropy alloy (HEA) that exhibits strong temperature dependence of strength at low homologous temperatures in sharp contrast to pure FCC metals like Ni that show weak temperature dependence is CrMnCoFeNi. In order to understand this behavior, elastic constants were determined as a function of temperature. From 300 K down to 55 K, the shear modulus (G) of the HEA changes by only 8%, increasing from 80 to 86 GPa. Moreover, this temperature dependence is weaker than that of FCC Ni, whose G increases by 12% (81–91 GPa). Therefore, the uncharacteristic temperature-dependence of the strength of the HEA ismore » not due to the temperature dependence of its shear modulus.« less

Fracture mechanisms in multilayer phosphorene assemblies: from brittle to ductile.

PubMed

Liu, Ning; Hong, Jiawang; Zeng, Xiaowei; Pidaparti, Ramana; Wang, Xianqiao

2017-05-24

The outstanding mechanical performance of nacre has stimulated numerous studies on the design of artificial nacres. Phosphorene, a new two-dimensional (2D) material, has a crystalline in-plane structure and non-bonded interaction between adjacent flakes. Therefore, multi-layer phosphorene assemblies (MLPs), in which phosphorene flakes are piled up in a staggered manner, may exhibit outstanding mechanical performance, especially exceptional toughness. Therefore, molecular dynamics simulations are performed to study the dependence of the mechanical properties on the overlap distance between adjacent phosphorene layers and the number of phosphorene flakes per layer. The results indicate that when the flake number is equal to 1, a transition of fracture patterns is observed by increasing the overlap distance, from a ductile failure controlled by interfacial friction to a brittle failure dominated by the breakage of covalent bonds inside phosphorene flakes. Moreover, the failure pattern can be tuned by changing the number of flakes in each phosphorene layer. The results imply that the ultimate strength follows a power law with the exponent -0.5 in terms of the flake number, which is in good agreement with our analytical model. Furthermore, the flake number in each phosphorene layer is optimized as 2 when the temperature is 1 K in order to potentially achieve both high toughness and strength. Moreover, our results regarding the relations between mechanical performance and overlap distance can be explained well using a shear-lag model. However, it should be pointed out that increasing the temperature of MLPs could cause the transition of fracture patterns from ductile to brittle. Therefore, the optimal flake number depends heavily on temperature to achieve both its outstanding strength and toughness. Overall, our findings unveil the fundamental mechanism at the nanoscale for MLPs as well as provide a method to design phosphorene-based structures with targeted properties via tunable overlap distance and flake number in phosphorene layers.

Iron modulates cell survival in a Ras- and MAPK-dependent manner in ovarian cells

PubMed Central

Bauckman, K A; Haller, E; Flores, I; Nanjundan, M

2013-01-01

Ovarian cancer is a leading cause of cancer death in women in the United States. While the majority of ovarian cancers are serous, some rarer subtypes (i.e. clear cell) are often associated with endometriosis, a benign gynecological disease. Iron is rich in the cyst fluid of endometriosis-associated ovarian cancers and induces persistent oxidative stress. The role of iron, an essential nutrient involved in multiple cellular functions, in normal ovarian cell survival and ovarian cancer remains unclear. Iron, presented as ferric ammonium citrate (FAC), dramatically inhibits cell survival in ovarian cancer cell types associated with Ras mutations, while it is without effect in immortalized normal ovarian surface epithelial (T80) and endometriotic epithelial cells (lacking Ras mutations). Interestingly, FAC induced changes in cytoplasmic vacuolation concurrently with increases in LC3-II levels (an autophagy marker); these changes occurred in an ATG5/ATG7-dependent, beclin-1/hVps34-independent, and Ras-independent manner. Knockdown of autophagy mediators in HEY ovarian cancer cells reversed FAC-induced LC3-II levels, but there was little effect on reversing the cell death response. Intriguingly, transmission electron microscopy of FAC-treated T80 cells demonstrated abundant lysosomes (confirmed using Lysotracker) rich in iron particles, which occurred in a Ras-independent manner. Although the mitogen-activated protein kinase (MAPK) inhibitor, U0126, reversed FAC-induced LC3-II/autophagic punctae and lysosomes in a Ras-independent manner, it was remarkable that U0126 reversed cell death in malignant ovarian cells associated with Ras mutations. Moreover, FAC increased heme oxygenase-1 expression in H-Ras-overexpressing T80 cells, which was associated with increased cell death when overexpressed in T80 cells. Disruption of intracellular iron levels, via chelation of intracellular iron (deferoxamine), was also detrimental to malignant ovarian cell survival; thus, homeostatic intracellular iron levels are essential for cell survival. Collectively, our results implicate iron in modulating cell death in a Ras- and MAPK-dependent manner in ovarian cancer cells. PMID:23598404

Low temperature and high pressure thermoelastic and crystallographic properties of SrZrO3 perovskite in the Pbnm phase

NASA Astrophysics Data System (ADS)

Knight, Kevin S.; Bull, Craig L.

2016-12-01

The thermoelastic and structural properties of SrZrO3 perovskite in the Pnma (Pbnm) phase have been studied using neutron powder diffraction at 82 temperatures between 11 K and 406 K at ambient pressure, and at sixteen pressures between 0.07 and 6.7 GPa at ambient temperature. The bulk modulus, derived by fitting the equation of state to a second order Birch-Murnaghan equation-of-state, 157(5) GPa, is in excellent agreement with that deduced in a recent resonant ultrasound investigation. Experimental axial compressional moduli are in agreement with those calculated from the elastic stiffness coefficients derived by ab-initio calculation, although the experimental bulk modulus is significantly softer than that calculated. Following low temperature saturation for temperatures less than 40 K, the unit cell monotonically increases with a predicted high temperature limit in the volume expansivity of ∼2.65 × 10-5 K-1. Axial linear thermal expansion coefficients are found to be in the order αb < αc < αa for all temperatures greater than 20 K with the b axis indicating a weak, low temperature negative expansion coefficient at low temperatures. The thermoelastic properties of SrZrO3 can be approximated by a two-term Debye model for the phonon density of states with Debye temperatures of 238(4) K and 713(6) K derived in a self-consistent manner by simultaneously fitting the isochoric heat capacity and the unit cell volume. Atomic displacement parameters have been fitted to a modified Debye model in which the zero-point term is an additional refinable variable and shows the cations and anions have well separated Debye temperatures, mirroring the need for two Debye-like distributions in the vibrational density of states. The temperature dependence of the crystal structure is presented in terms of the amplitudes of the seven symmetry-adapted basis vectors of the aristotype phase that are consistent with space group Pbnm, thus permitting a direct measure of the order parameter evolution in SrZrO3. The temperature variation of the in-phase tilt, which is lost at the phase transition at 973 K, is consistent with tricritical behaviour, in agreement with published results based on high temperature crystallographic data.

Field significance of performance measures in the context of regional climate model evaluation. Part 1: temperature

NASA Astrophysics Data System (ADS)

Ivanov, Martin; Warrach-Sagi, Kirsten; Wulfmeyer, Volker

2018-04-01

A new approach for rigorous spatial analysis of the downscaling performance of regional climate model (RCM) simulations is introduced. It is based on a multiple comparison of the local tests at the grid cells and is also known as "field" or "global" significance. New performance measures for estimating the added value of downscaled data relative to the large-scale forcing fields are developed. The methodology is exemplarily applied to a standard EURO-CORDEX hindcast simulation with the Weather Research and Forecasting (WRF) model coupled with the land surface model NOAH at 0.11 ∘ grid resolution. Monthly temperature climatology for the 1990-2009 period is analysed for Germany for winter and summer in comparison with high-resolution gridded observations from the German Weather Service. The field significance test controls the proportion of falsely rejected local tests in a meaningful way and is robust to spatial dependence. Hence, the spatial patterns of the statistically significant local tests are also meaningful. We interpret them from a process-oriented perspective. In winter and in most regions in summer, the downscaled distributions are statistically indistinguishable from the observed ones. A systematic cold summer bias occurs in deep river valleys due to overestimated elevations, in coastal areas due probably to enhanced sea breeze circulation, and over large lakes due to the interpolation of water temperatures. Urban areas in concave topography forms have a warm summer bias due to the strong heat islands, not reflected in the observations. WRF-NOAH generates appropriate fine-scale features in the monthly temperature field over regions of complex topography, but over spatially homogeneous areas even small biases can lead to significant deteriorations relative to the driving reanalysis. As the added value of global climate model (GCM)-driven simulations cannot be smaller than this perfect-boundary estimate, this work demonstrates in a rigorous manner the clear additional value of dynamical downscaling over global climate simulations. The evaluation methodology has a broad spectrum of applicability as it is distribution-free, robust to spatial dependence, and accounts for time series structure.

Rational design of an improved tissue-engineered vascular graft: determining the optimal cell dose and incubation time.

PubMed

Lee, Yong-Ung; Mahler, Nathan; Best, Cameron A; Tara, Shuhei; Sugiura, Tadahisa; Lee, Avione Y; Yi, Tai; Hibino, Narutoshi; Shinoka, Toshiharu; Breuer, Christopher

2016-03-01

We investigated the effect of cell seeding dose and incubation time on tissue-engineered vascular graft (TEVG) patency. Various doses of bone marrow-derived mononuclear cells (BM-MNCs) were seeded onto TEVGs, incubated for 0 or 12 h, and implanted in C57BL/6 mice. Different doses of human BM-MNCs were seeded onto TEVGs and measured for cell attachment. The incubation time showed no significant effect on TEVG patency. However, TEVG patency was significantly increased in a dose-dependent manner. In the human graft, more bone marrow used for seeding resulted in increased cell attachment in a dose-dependent manner. Increasing the BM-MNC dose and reducing incubation time is a viable strategy for improving the performance and utility of the graft.

Oily fraction of Semecarpus anacardium Linn nuts involves protein kinase C activation for its pro-inflammatory response.

PubMed

Tripathi, Yamini B; Pandey, Nidhi; Tripathi, Deepshikha; Tripathi, Pratibha

2010-12-01

The oily fraction (non polar fraction-NPF) of S. anacardium (SA) significantly increased the expression of protein kinase C-delta (PKC-delta) in macrophages in concentration dependent manner, which was similar to phorbol myristate acetate (PMA) response. Further, H-7 (1-(5-isoquinolinesulphonyl)-2-methylpiperazine), an inhibitor of PKC significantly inhibited this NPF mediated response in a concentration dependent manner. In the post treatment kinetics, H-7 showed this inhibition only up to 6 min post NPF/PMA addition, but in similar condition, quercetin, a flavone with reported antioxidant property, showed this inhibition only up to 2 min. The results clearly suggest that oily fraction of SA nuts enhances the expression of PKC protein, which may be responsible for its reported pro-inflammatory property.

Dolphin natures, human virtues: MacIntyre and ethical naturalism.

PubMed

Glackin, Shane Nicholas

2008-09-01

Can biological facts explain human morality? Aristotelian 'virtue' ethics has traditionally assumed so. In recent years Alasdair MacIntyre has reintroduced a form of Aristotle's 'metaphysical biology' into his ethics. He argues that the ethological study of dependence and rationality in other species--dolphins in particular--sheds light on how those same traits in the typical lives of humans give rise to the moral virtues. However, some goal-oriented dolphin behaviour appears both dependent and rational in the precise manner which impresses MacIntyre, yet anything but ethically 'virtuous'. More damningly, dolphin ethologists consistently refuse to evaluate such behaviour in the manner MacIntyre claims is appropriate to moral judgement. In light of this, I argue that virtues--insofar as they name a biological or ethological category--do not name a morally significant one.

Antiviral effect of lithium chloride on infection of cells by canine parvovirus.

PubMed

Zhou, Pei; Fu, Xinliang; Yan, Zhongshan; Fang, Bo; Huang, San; Fu, Cheng; Hong, Malin; Li, Shoujun

2015-11-01

Canine parvovirus type 2 causes significant viral disease in dogs, with high morbidity, high infectivity, and high mortality. Lithium chloride is a potential antiviral drug for viruses. We determined the antiviral effect of Lithium Chloride on canine parvovirus type 2 in feline kidney cells. The viral DNA and proteins of canine parvovirus were suppressed in a dose-dependent manner by lithium chloride. Further investigation verified that viral entry into cells was inhibited in a dose-dependent manner by lithium chloride. These results indicated that lithium chloride could be a potential antiviral drug for curing dogs with canine parvovirus infection. The specific steps of canine parvovirus entry into cells that are affected by lithium chloride and its antiviral effect in vivo should be explored in future studies.

[The anti-tumour effect of Wuxing soup and its mechanism in inducing apoptosis of tumour cells mediated by calcium].

PubMed

Mo, Fei; Hu, Jing-Ying; Gan, Yu; Zhao, Yang-Xing; Zhao, Xin-Tai

2008-09-01

To confirm the anti-cancer effect and mechanism of Wuxing soup. Inhibition of cellular growth under Wuxing soup treatment was observed by MTT; Apoptosis was detected by gel electrophoresis, transmission electron microscopy and FACS; The concentration of calcium was measured by fluorescence probe. After SGC-7901 cell being treated by Wuxing soup, it showed that: 1) Wuxing soup could specifically inhibit cancer cells proliferation in a time and dose dependent manner; 2) Typical apoptotic morphological changes and DNA ladder of SGC-7901 cells were observed; 3) calcium inhibitor Bapta AM could reduce the apoptotic rate and protect SGC-7901 cells in a dose dependent manner. Wuxing soup has an effective inhibition on cancer cells, and can induce SGC-7901 cells to apoptosis by calcium.

Regression Analysis and Calibration Recommendations for the Characterization of Balance Temperature Effects

NASA Technical Reports Server (NTRS)

Ulbrich, N.; Volden, T.

2018-01-01

Analysis and use of temperature-dependent wind tunnel strain-gage balance calibration data are discussed in the paper. First, three different methods are presented and compared that may be used to process temperature-dependent strain-gage balance data. The first method uses an extended set of independent variables in order to process the data and predict balance loads. The second method applies an extended load iteration equation during the analysis of balance calibration data. The third method uses temperature-dependent sensitivities for the data analysis. Physical interpretations of the most important temperature-dependent regression model terms are provided that relate temperature compensation imperfections and the temperature-dependent nature of the gage factor to sets of regression model terms. Finally, balance calibration recommendations are listed so that temperature-dependent calibration data can be obtained and successfully processed using the reviewed analysis methods.

Selecting Temperature for Protein Crystallization Screens Using the Temperature Dependence of the Second Virial Coefficient

PubMed Central

Liu, Jun; Yin, Da-Chuan; Guo, Yun-Zhu; Wang, Xi-Kai; Xie, Si-Xiao; Lu, Qin-Qin; Liu, Yong-Ming

2011-01-01

Protein crystals usually grow at a preferable temperature which is however not known for a new protein. This paper reports a new approach for determination of favorable crystallization temperature, which can be adopted to facilitate the crystallization screening process. By taking advantage of the correlation between the temperature dependence of the second virial coefficient (B 22) and the solubility of protein, we measured the temperature dependence of B 22 to predict the temperature dependence of the solubility. Using information about solubility versus temperature, a preferred crystallization temperature can be proposed. If B 22 is a positive function of the temperature, a lower crystallization temperature is recommended; if B 22 shows opposite behavior with respect to the temperature, a higher crystallization temperature is preferred. Otherwise, any temperature in the tested range can be used. PMID:21479212

Human stem cell–derived astrocytes replicate human prions in a PRNP genotype–dependent manner

PubMed Central

Krejciova, Zuzana; Alibhai, James; Zhao, Chen; Rzechorzek, Nina M.; Ullian, Erik M.; Manson, Jean

2017-01-01

Prions are infectious agents that cause neurodegenerative diseases such as Creutzfeldt–Jakob disease (CJD). The absence of a human cell culture model that replicates human prions has hampered prion disease research for decades. In this paper, we show that astrocytes derived from human induced pluripotent stem cells (iPSCs) support the replication of prions from brain samples of CJD patients. For experimental exposure of astrocytes to variant CJD (vCJD), the kinetics of prion replication occur in a prion protein codon 129 genotype–dependent manner, reflecting the genotype-dependent susceptibility to clinical vCJD found in patients. Furthermore, iPSC-derived astrocytes can replicate prions associated with the major sporadic CJD strains found in human patients. Lastly, we demonstrate the subpassage of prions from infected to naive astrocyte cultures, indicating the generation of prion infectivity in vitro. Our study addresses a long-standing gap in the repertoire of human prion disease research, providing a new in vitro system for accelerated mechanistic studies and drug discovery. PMID:29141869

A Butter Aroma Recombinate Activates Human Class-I Odorant Receptors.

PubMed

Geithe, Christiane; Andersen, Gaby; Malki, Agne; Krautwurst, Dietmar

2015-11-04

With ∼400 olfactory G protein-coupled receptors (GPCR), humans sensitively perceive ∼230 key aroma compounds as best natural agonists of ∼10000 food volatiles. An understanding of odorant coding, thus, critically depends on the knowledge about interactions of key food aroma chemicals and their mixtures with their cognate receptors. Genetically designed test cell systems enable the screening, deorphaning, and characterization of single odorant receptors (OR). This study shows for the food aroma-specific and quantitative butter aroma recombinate, and its single components, specific in vitro class-I OR activity patterns, as well as the activation of selected OR in a concentration-dependent manner. Recently, chemosensory receptors, especially class-I OR, were demonstrated to be expressed on blood leukocytes, which may encounter foodborne aroma compounds postprandially. This study shows that butter aroma recombinate induced chemotaxis of isolated human neutrophils in a defined gradient, and in a concentration-dependent and pertussis toxin-sensitive manner, suggesting at least a GPCR-mediated activation of blood leukocytes by key food odorants.

Uncaria rhynchophylla induces angiogenesis in vitro and in vivo.

PubMed

Choi, Do-Young; Huh, Jeong-Eun; Lee, Jae-Dong; Cho, Eun-Mi; Baek, Yong-Hyeon; Yang, Ha-Ru; Cho, Yoon-Je; Kim, Kang-Il; Kim, Deog-Yoon; Park, Dong-Suk

2005-12-01

Angiogenesis consists of the proliferation, migration, and differentiation of endothelial cells, and angiogenic factors and matrix protein interactions modulate this process. The aim of this study was to determine the angiogenic properties of Uncaria rhynchophylla. Uncaria rhynchophylla significantly enhanced human umbilical vein endothelial cells (HUVECs) proliferation in a dose-dependent manner. Neutralization of vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) by monoclonal antibody suppressed the Uncaria rhynchophylla stimulatory effect on proliferation. In addition, Uncaria rhynchophylla significantly increased chemotactic-migration on gelatin and tubular structures on Matrigel of HUVECs in a dose-dependent manner. Interestingly, Uncaria rhynchophylla dose-dependently increased VEGF, and bFGF gene expression and protein secretion of HUVEC. The angiogenic activity of Uncaria rhynchophylla was confirmed using an in vivo Matrigel angiogenesis model, showing promotion of blood vessel formation. These results suggest that Uncaria rhynchophylla could potentially used to accelerate vascular wound healing or to promote the growth of collateral blood vessel in ischemic tissues.

Temperature dependence of tris(2,2'-bipyridine) ruthenium (II) device characteristics

NASA Astrophysics Data System (ADS)

Slinker, Jason D.; Malliaras, George G.; Flores-Torres, Samuel; Abruña, Héctor D.; Chunwachirasiri, Withoon; Winokur, Michael J.

2004-04-01

We have investigated the temperature dependence of the current, radiance, and efficiency from electroluminescent devices based on [Ru(bpy)3]2+(PF6-)2, where bpy is 2,2'-bipyridine. We find that the current increases monotonically with temperature from 200 to 380 K, while the radiance reaches a maximum near room temperature. For temperatures greater than room temperature, an irreversible, current-induced degradation occurs with thermal cycling that diminishes both the radiance and the photoluminescence (PL) quantum yield, but does not affect the current. The temperature dependence of the external quantum efficiency is fully accounted for by the dependence of the PL quantum yield as measured from the emissive area of the device. This implies that the contacts remain ohmic throughout the temperature range investigated. The quenching of the PL with temperature was attributed to thermal activation to a nonradiative d-d transition. The temperature dependence of the current shows a complex behavior in which transport appears to be thermally activated, with distinct low-temperature and high-temperature regimes.

Relative Influence of Intrinsic and Extrinsic Factors on the Metal-Insulator Transition of VO2 Nanowires

NASA Astrophysics Data System (ADS)

Kim, In Soo

The influence of stoichiometry on the metal-insulator transition of vanadium dioxide (VO2) nanowires was investigated using Raman spectroscopy. Controlled reduction of nominally strain-free suspended VO2 nanowires was conducted by rapid thermal annealing (RTA). The deficiency in oxygen assisted in the unprecedented suppression of the metallic (R) phase to temperatures as low as 103 K through generation of free electrons. In a complementary manner, oxygen-rich conditions stabilized the metastable monoclinic (M2) and triclinic (T) phases. A pseudo-phase diagram with dimensions of temperature and stoichiometry was established, highlighting the accessibility of new phases in the nanowire geometry. Detection of the dynamic elastic response across the metal-insulator transition in suspended VO2 nanowires was enabled by fiber-coupled polarization dependent interferometry. Dual-beam Raman spectroscopy was developed to determine the local domain/phase structure of VO2 nanowires, which allowed for accurate modeling using COMSOL finite element analysis (FEA). The Young's moduli of the single crystal insulating (M1) and metallic (R) phases without artifacts were determined for the first time. The sources of dissipation were identified as clamping losses, structural losses, thermoelastic damping, and domain wall motion. While contribution of thermoelastic damping was found to be dominant in the terminal phases, extraordinary dissipation was observed upon formation and movement of domain walls. Finally, it was shown that creation of local defects could lead to new classes of tunable sensors with a discrete and programmable frequency response with temperature.

The Influence of Prior Modes of Growth, Temperature, Medium, and Substrate Surface on Biofilm Formation by Antibiotic-Resistant Campylobacter jejuni.

PubMed

Teh, Amy Huei Teen; Lee, Sui Mae; Dykes, Gary A

2016-12-01

Campylobacter jejuni is one of the most common causes of bacterial gastrointestinal food-borne infection worldwide. It has been suggested that biofilm formation may play a role in survival of these bacteria in the environment. In this study, the influence of prior modes of growth (planktonic or sessile), temperatures (37 and 42 °C), and nutrient conditions (nutrient broth and Mueller-Hinton broth) on biofilm formation by eight C. jejuni strains with different antibiotic resistance profiles was examined. The ability of these strains to form biofilm on different abiotic surfaces (stainless steel, glass, and polystyrene) as well as factors potentially associated with biofilm formation (bacterial surface hydrophobicity, auto-aggregation, and initial attachment) was also determined. The results showed that cells grown as sessile culture generally have a greater ability to form biofilm (P < 0.05) compared to their planktonic counterparts. Biofilm was also greater (P < 0.05) in lower nutrient media, while growth at different temperatures affects biofilm formation in a strain-dependent manner. The strains were able to attach and form biofilms on different abiotic surfaces, but none of them demonstrated strong, complex, or structured biofilm formation. There were no clear trends between the bacterial surface hydrophobicity, auto-aggregation, attachment, and biofilm formation by the strains. This finding suggests that environmental factors did affect biofilm formation by C. jejuni, and they are more likely to persist in the environment in the form of mixed-species rather than monospecies biofilms.

Enlightening the ultrahigh electrical conductivities of doped double-wall carbon nanotube fibers by Raman spectroscopy and first-principles calculations.

PubMed

Tristant, Damien; Zubair, Ahmed; Puech, Pascal; Neumayer, Frédéric; Moyano, Sébastien; Headrick, Robert J; Tsentalovich, Dmitri E; Young, Colin C; Gerber, Iann C; Pasquali, Matteo; Kono, Junichiro; Leotin, Jean

2016-12-01

Highly aligned, packed, and doped carbon nanotube (CNT) fibers with electrical conductivities approaching that of copper have recently become available. These fibers are promising for high-power electrical applications that require light-weight, high current-carrying capacity cables. However, a microscopic understanding of how doping affects the electrical conductance of such CNT fibers in a quantitative manner has been lacking. Here, we performed Raman spectroscopy measurements combined with first-principles calculations to determine the position of the average Fermi energy and to obtain the temperature of chlorosulfonic-acid-doped double-wall CNT fibers under high current. Due to the unique way in which double-wall CNT Raman spectra depend on doping, it is possible to use Raman data to determine the doping level quantitatively. The correspondence between the Fermi level shift and the carbon charge transfer is derived from a tight-binding model and validated by several calculations. For the doped fiber, we were able to associate an average Fermi energy shift of ∼-0.7 eV with a conductance increase by a factor of ∼5. Furthermore, since current induces heating, local temperature determination is possible. Through the Stokes-to-anti-Stokes intensity ratio of the G-band peaks, we estimated a temperature rise at the fiber surface of ∼135 K at a current density of 2.27 × 10 8 A m -2 identical to that from the G-band shift, suggesting that thermalization between CNTs is well achieved.

Statistics and topology of the COBE differential microwave radiometer first-year sky maps

NASA Technical Reports Server (NTRS)

Smoot, G. F.; Tenorio, L.; Banday, A. J.; Kogut, A.; Wright, E. L.; Hinshaw, G.; Bennett, C. L.

1994-01-01

We use statistical and topological quantities to test the Cosmic Background Explorer (COBE) Differential Microwave Radiometer (DMR) first-year sky maps against the hypothesis that the observed temperature fluctuations reflect Gaussian initial density perturbations with random phases. Recent papers discuss specific quantities as discriminators between Gaussian and non-Gaussian behavior, but the treatment of instrumental noise on the data is largely ignored. The presence of noise in the data biases many statistical quantities in a manner dependent on both the noise properties and the unknown cosmic microwave background temperature field. Appropriate weighting schemes can minimize this effect, but it cannot be completely eliminated. Analytic expressions are presented for these biases, and Monte Carlo simulations are used to assess the best strategy for determining cosmologically interesting information from noisy data. The genus is a robust discriminator that can be used to estimate the power-law quadrupole-normalized amplitude, Q(sub rms-PS), independently of the two-point correlation function. The genus of the DMR data is consistent with Gaussian initial fluctuations with Q(sub rms-PS) = (15.7 +/- 2.2) - (6.6 +/- 0.3)(n - 1) micro-K, where n is the power-law index. Fitting the rms temperature variations at various smoothing angles gives Q(sub rms-PS) = 13.2 +/- 2.5 micro-K and n = 1.7(sup (+0.3) sub (-0.6)). While consistent with Gaussian fluctuations, the first year data are only sufficient to rule out strongly non-Gaussian distributions of fluctuations.

D-Dimensional Dirac Equation for Energy-Dependent Pseudoharmonic and Mie-type Potentials via SUSYQM

NASA Astrophysics Data System (ADS)

A. N., Ikot; Hassanabadi, H.; Maghsoodi, E.; Zarrinkamar, S.

2014-04-01

We investigate the approximate solution of the Dirac equation for energy-dependent pseudoharmonic and Mie-type potentials under the pseudospin and spin symmetries using the supersymmetry quantum mechanics. We obtain the bound-state energy equation in an analytical manner and comment on the system behavior via various figures and tables.

Dynamical role of predators in population cycles of a forest insect: an experimental test.

Treesearch

P. Turchin; A.D. Taylor; J.D. Reeve

1999-01-01

Population cycles occur frequently in forest insects.Time-series analysis of fluctuations in one such insect, the southern pine beetle (Dendroctonus frontalis), suggests that beetle dynamics are dominated by an ecological process acting in a delayed density-dependent manner.The hypothesis that delayed density-dependence in this insect results from its interaction with...

Principles of Experience-Dependent Neural Plasticity: Implications for Rehabilitation after Brain Damage

ERIC Educational Resources Information Center

Kleim, Jeffrey A.; Jones, Theresa A.

2008-01-01

Purpose: This paper reviews 10 principles of experience-dependent neural plasticity and considerations in applying them to the damaged brain. Method: Neuroscience research using a variety of models of learning, neurological disease, and trauma are reviewed from the perspective of basic neuroscientists but in a manner intended to be useful for the…

40 CFR 230.6 - Adaptability.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) The manner in which these Guidelines are used depends on the physical, biological, and chemical nature... making determinations as to the relevance of any portion(s) of the Guidelines and conducting further...

40 CFR 230.6 - Adaptability.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) The manner in which these Guidelines are used depends on the physical, biological, and chemical nature... making determinations as to the relevance of any portion(s) of the Guidelines and conducting further...

40 CFR 230.6 - Adaptability.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) The manner in which these Guidelines are used depends on the physical, biological, and chemical nature... making determinations as to the relevance of any portion(s) of the Guidelines and conducting further...

Interactions between benzylamiloride and fura-2: studies in vitro and in cardiac myocytes.

PubMed

Hudson, C A; Rojas, J D; Sarvazyan, N; Wesson, D E; Martínez-Zaguilán, R

1998-08-01

Amiloride derivatives are commonly used inhibitors of Na+/H+- and Na+/Ca2+-exchange. Because they are fluorescent molecules the use of benzylamiloride (BZA), an inhibitor of Na+/Ca2+ exchange, in conjunction with Fura-2, a commonly used fluorescent Ca2+ indicator, might complicate interpretation of fluorescence data obtained. In vitro data show that BZA decreases the Fura-2 fluorescence at all useful wavelengths in a concentration-dependent manner. The Fura-2 ratio 340/380 (used to estimate intracellular Ca2+ ([Ca2+]in)) also decreased with increasing BZA concentrations. The Stern-Volmer relation suggests that this phenomenon is due to either static or dynamic quenching. Varying temperatures from 4 to 37 degreesC did not alter Stern-Volmer constants, consistent instead with fluorescence resonance energy transfer (FRET). The in situ relevance of these interactions was evaluated in adult rat cardiac myocytes which exhibit Na+/Ca2+ exchange reflected by rapid [Ca2+]in increase following Na+ removal. Pretreatment with BZA >/= 25 microM decreased the magnitude of Fura-2 changes induced by Na+ removal. Analysis of the individual Fura-2 useful wavelengths indicated that >/= 25 microM BZA altered the Fura-2 signal in a manner consistent with the quenching effects noted in vitro. Together, these data show that BZA interacts with Fura-2 in vitro and in situ and suggest caution when interpreting Fura-2 fluorescence data derived in conjunction with BZA. Copyright 1998 Academic Press.

Agonist-mediated activation of Bombyx mori diapause hormone receptor signals to extracellular signal-regulated kinases 1 and 2 through Gq-PLC-PKC-dependent cascade.

PubMed

Jiang, Xue; Yang, Jingwen; Shen, Zhangfei; Chen, Yajie; Shi, Liangen; Zhou, Naiming

2016-08-01

Diapause is a developmental strategy adopted by insects to survive in challenging environments such as the low temperatures of a winter. This unique process is regulated by diapause hormone (DH), which is a neuropeptide hormone that induces egg diapause in Bombyx mori and is involved in terminating pupal diapause in heliothis moths. An G protein-coupled receptor from the silkworm, B. mori, has been identified as a specific cell surface receptor for DH. However, the detailed information on the DH-DHR system and its mechanism(s) involved in the induction of embryonic diapause remains unknown. Here, we combined functional assays with various specific inhibitors to elucidate the DHR-mediated signaling pathways. Upon activation by DH, B. mori DHR is coupled to the Gq protein, leading to a significant increase of intracellular Ca(2+) and cAMP response element-driven luciferase activity in an UBO-QIC, a specific Gq inhibitor, sensitive manner. B. mori DHR elicited ERK1/2 phosphorylation in a dose- and time-dependent manner in response to DH. This effect was almost completely inhibited by co-incubation with UBO-QIC and was also significantly suppressed by PLC inhibitor U73122, PKC inhibitors Gö6983 and the Ca(2+) chelator EGTA. Moreover, DHR-induced activation of ERK1/2 was significantly attenuated by treatment with the Gβγ specific inhibitors gallein and M119K and the PI3K specific inhibitor Wortmannin, but not by the Src specific inhibitor PP2. Our data also demonstrates that the EGFR-transactivation pathway is not involved in the DHR-mediated ERK1/2 phosphorylation. Future efforts are needed to clarify the role of the ERK1/2 signaling pathway in the DH-mediated induction of B. mori embryonic diapause. Copyright © 2016 Elsevier Ltd. All rights reserved.

Trehalose acts as a uridine 5'-diphosphoglucose-competitive inhibitor of trehalose 6-phosphate synthase in Corynebacterium glutamicum.

PubMed

Oide, Shinichi; Inui, Masayuki

2017-12-01

Trehalose is a compatible solute widely distributed in nature. The most prevalent pathway for its synthesis starts from condensation of glucose 6-phosphate (Glc6P) and uridine 5'-diphosphoglucose (UDP-Glc) catalyzed by trehalose 6-phosphate synthase (TPS). A previous laboratory evolution experiment with the bacterium Corynebacterium glutamicum generated strains adapted to supraoptimal temperatures, and the R328H substitution of the TPS encoded by otsA was shown to be associated with thermotolerance acquired by the evolved strains. In this study, we found that the OtsA:R328H substitution promotes both intra- and extracellular trehalose accumulation and demonstrated that build-up of intracellular trehalose accounts for the OtsA R 328H -dependent thermotolerance, using the mycobacterial trehalose-specific transporter. Counterintuitively, characterization of the recombinant OtsA proteins revealed that the mutation downshifts the temperature optimum of OtsA. A search for the molecular basis of OtsA R 328H -dependent enhancement of trehalose synthesis led to the unexpected findings that trehalose is an effective inhibitor of OtsA and that OtsA R 328H is highly tolerant to the trehalose-mediated inhibition. The only available report on such feedback regulation of TPS is for the silk moth from over 50 years ago [Murphy TA and Wyatt GR (1965) J Biol Chem 240, 1500-1508]. While trehalose acts as a Glc6P-competitive inhibitor in the silk moth, the disaccharide was found to inhibit OtsA in a UDP-Glc-competitive manner in C. glutamicum, suggesting independent origins of the negative feedback regulations found for the two species. We showed that overexpression of the wild-type OtsA counteracts the trehalose-dependent regulation and restores the evolved strain-like phenotype to the isogenic wild-type otsA revertant, demonstrating that thermotolerance conferred by OtsA R 328H is attributable to its feedback-resistant property. © 2017 Federation of European Biochemical Societies.

Estimation of mortality for stage-structured zooplankton populations: What is to be done?

NASA Astrophysics Data System (ADS)

Ohman, Mark D.

2012-05-01

Estimation of zooplankton mortality rates in field populations is a challenging task that some contend is inherently intractable. This paper examines several of the objections that are commonly raised to efforts to estimate mortality. We find that there are circumstances in the field where it is possible to sequentially sample the same population and to resolve biologically caused mortality, albeit with error. Precision can be improved with sampling directed by knowledge of the physical structure of the water column, combined with adequate sample replication. Intercalibration of sampling methods can make it possible to sample across the life history in a quantitative manner. Rates of development can be constrained by laboratory-based estimates of stage durations from temperature- and food-dependent functions, mesocosm studies of molting rates, or approximation of development rates from growth rates, combined with the vertical distributions of organisms in relation to food and temperature gradients. Careful design of field studies guided by the assumptions of specific estimation models can lead to satisfactory mortality estimates, but model uncertainty also needs to be quantified. We highlight additional issues requiring attention to further advance the field, including the need for linked cooperative studies of the rates and causes of mortality of co-occurring holozooplankton and ichthyoplankton.

Factors Controlling Stress Rupture of Fiber-Reinforced Ceramic Composites

NASA Technical Reports Server (NTRS)

DiCarlo, J. A.; Yun, H. M.

1999-01-01

The successful application of fiber-reinforced ceramic matrix composites (CMC) depends strongly on maximizing material rupture life over a wide range of temperatures and applied stresses. The objective of this paper is to examine the various intrinsic and extrinsic factors that control the high-temperature stress rupture of CMC for stresses below and above those required for cracking of the 0 C plies (Regions I and II, respectively). Using creep-rupture results for a variety of ceramic fibers and rupture data for CMC reinforced by these fibers, it is shown that in those cases where the matrix carries little structural load, CMC rupture conditions can be predicted very well from the fiber behavior measured under the appropriate test environment. As such, one can then examine the intrinsic characteristics of the fibers in order to develop design guidelines for selecting fibers and fiber microstructures in order to maximize CMC rupture life. For those cases where the fiber interfacial coatings are unstable in the test environment, CMC lives are generally worse than those predicted by fiber behavior alone. For those cases where the matrix can support structural load, CMC life can even be greater provided matrix creep behavior is properly controlled. Thus the achievement of long CMC rupture life requires understanding and optimizing the behavior of all constituents in the proper manner.

Optimization for ultrasound-assisted extraction of polysaccharides with chemical composition and antioxidant activity from the Artemisia sphaerocephala Krasch seeds.

PubMed

Zheng, Quan; Ren, Daoyuan; Yang, Nana; Yang, Xingbin

2016-10-01

Artemisia sphaerocephala Krasch seeds polysaccharides have been reported to have a variety of important biological activities. However, effective extraction of Artemisia sphaerocephala Krasch seeds polysaccharides is still an unsolved issue. In this study, the orthogonal rotatable central composite design was employed to optimize ultrasound-assisted extraction conditions of Artemisia sphaerocephala Krasch seeds polysaccharides. Based on a single-factor analysis method, ultrasonic power, extraction time, solid-liquid ratio and extraction temperature were shown to significantly affect the yield of polysaccharides extracted from the A. sphaerocephala Krasch seeds. The optimal conditions for extraction of Artemisia sphaerocephala Krasch seeds polysaccharides were determined as following: ultrasonic power 243W, extraction time 125min, solid-liquid ratio 64:1 and extraction temperature 64°C, where the experimental yield was 14.78%, which was well matched with the predicted value of 14.81%. Furthermore, ASKP was identified as a typical heteropolysaccharide with d-galacturonic acid (38.8%) d-galactose (20.2%) and d-xylose (15.5%) being the main constitutive monosaccharides. Moreover, Artemisia sphaerocephala Krasch seeds polysaccharides exhibited high total reducing power and considerable scavenging activities on DPPH, hydroxyl and superoxide radicals, in a concentration-dependent manner in vitro. Copyright © 2016 Elsevier B.V. All rights reserved.

3D Printed Reversible Shape Changing Components with Stimuli Responsive Materials

PubMed Central

Mao, Yiqi; Ding, Zhen; Yuan, Chao; Ai, Shigang; Isakov, Michael; Wu, Jiangtao; Wang, Tiejun; Dunn, Martin L.; Qi, H. Jerry

2016-01-01

The creation of reversibly-actuating components that alter their shapes in a controllable manner in response to environmental stimuli is a grand challenge in active materials, structures, and robotics. Here we demonstrate a new reversible shape-changing component design concept enabled by 3D printing two stimuli responsive polymers—shape memory polymers and hydrogels—in prescribed 3D architectures. This approach uses the swelling of a hydrogel as the driving force for the shape change, and the temperature-dependent modulus of a shape memory polymer to regulate the time of such shape change. Controlling the temperature and aqueous environment allows switching between two stable configurations – the structures are relatively stiff and can carry load in each – without any mechanical loading and unloading. Specific shape changing scenarios, e.g., based on bending, or twisting in prescribed directions, are enabled via the controlled interplay between the active materials and the 3D printed architectures. The physical phenomena are complex and nonintuitive, and so to help understand the interplay of geometric, material, and environmental stimuli parameters we develop 3D nonlinear finite element models. Finally, we create several 2D and 3D shape changing components that demonstrate the role of key parameters and illustrate the broad application potential of the proposed approach. PMID:27109063

Low temperature heat treatments of AA5754-Ti6Al4V dissimilar laser welds: Microstructure evolution and mechanical properties

NASA Astrophysics Data System (ADS)

Leo, P.; D'Ostuni, S.; Casalino, G.

2018-03-01

This paper presents the effects of the post welding heat treatments (PWHT) performed at 350 °C and 450 °C on the microstructure evolution and mechanical properties of AA5754 and Ti6Al4V dissimilar laser welds. The microstructure and tensile properties of the welds before and after low temperature treatment were analyzed. The off-set welding technique was applied to limit the formation of brittle intermetallic compounds during the welding process. The laser beam was directed onto the titanium side at a small distance from the aluminum edge. The keyhole formed and the full penetration was reached in the titanium side of the weld. Thereafter, the aluminum side melted as the heat that formed the keyhole transferred from the titanium fused zone. Two different energy lines (32 J/mm and 76 J/mm) were used. In this manner, a fused and a heat affected zones was revealed on both sides of the weld. Several intermetallic compounds formed in the intermetallic layer between the two metals. The thickness and the composition of the intermetallic layer depended on the welding parameters and the post welding heat treatment. The hardness and tensile properties of the welds before and after the post welding heat treatment were measured and analyzed.

Gonadotrophic cells and gonadal sex differentiation in medaka: Characterization of several northern and southern strains.

PubMed

Horie, Yoshifumi; Kobayashi, Tohru

2015-07-01

Gonadotropins play an important role in gametogenesis and reproduction in vertebrates. Their localization in the pituitary during gonadal sex differentiation has been studied mainly in southern (Oryzias latipes) strains of medaka fish, with that in northern medaka (O. sakaizumii) remaining poorly understood. Hence, in this study, we characterized gonadal differentiation and gonadotrophic cells during sex differentiation in two northern strains (HNI and Kaga) and two southern strains (Hd-rR and d-rR/Tokyo). All strains exhibited similar sex differentiation at hatching, such as (1) sex difference in germ cell number (XX > XY), and (2) the transition of XX germ cells into meiosis, and (3) presence of glycoprotein-α (Gpa)-positive cells. However, follicle-stimulating hormone-β (Fshb)-positive cells were first detected in the pituitary 1 day post-hatching in HNI. Exposure to high-temperature conditions and to cortisol in a dose dependent manner resulted in the localization of Fshb cells in the pituitary at hatching. This study demonstrates differences in gonadotropin subunit expression between northern and southern strains of medaka, and suggests that Fsh is not involved in early gonadal sex differentiation, such as the sex difference in germ cell number, and that high-temperature induce Fshb expression via cortisol production in medaka. © 2015 Wiley Periodicals, Inc.

Imaging the distribution of sodium dodecyl sulfate in skin by confocal Raman and infrared microspectroscopy.

PubMed

Mao, G; Flach, C R; Mendelsohn, R; Walters, R M

2012-08-01

To image SDS distribution across different skin regions, to compare the permeability difference between porcine and human skin, and to evaluate the interaction between SDS and skin. Full thickness porcine and human skin was treated with acyl chain perdeuterated SDS (SDS-d(25)) at room temperature and at 34 °C for 3, 24 and 40 h. SDS distribution in skin was monitored by confocal Raman and IR microspectroscopic imaging. Permeation profiles of SDS-d(25) in skin were derived from the band intensities of the CD(2) stretching vibrations. The interaction between SDS and skin was monitored through the CH(2) and CD(2) stretching frequencies and the Amide I and II spectral region. SDS-d(25) penetrates both porcine and human skin in a time and temperature-dependent manner, with slightly higher permeability through the stratum corneum (SC) in porcine skin. When SDS permeates into the SC, its chains are more ordered compared to SDS micelles. The secondary structure of keratin in the SC is not affected by SDS-d(25). The spatial distribution of SDS-d(25) in skin was obtained for the first time. Infrared microscopic imaging provides unique opportunities to measure concentration profiles of exogenous materials in skin and offers insights to interaction between permeants and skin.

Conjugal Transfer of the Pathogenicity Island ROD21 in Salmonella enterica serovar Enteritidis Depends on Environmental Conditions

PubMed Central

Salazar-Echegarai, Francisco J.; Tobar, Hugo E.; Nieto, Pamela A.; Riedel, Claudia A.; Bueno, Susan M.

2014-01-01

Unstable pathogenicity islands are chromosomal elements that can be transferred from one bacterium to another. Salmonella enterica serovar Enteritidis (S. Enteritidis) is a pathogenic bacterium containing such unstable pathogenicity islands. One of them, denominated ROD21, is 26.5 kb in size and capable of excising from the chromosome in certain culture conditions, as well as during bacterial infection of phagocytic cells. In this study we have evaluated whether ROD21 can be effectively transferred from one bacterium to another. We generated a donor and several recipient strains of S. Enteritidis to carry out transfer assays in liquid LB medium. These assays showed that ROD21 is effectively transferred from donor to recipient strains of S. Enteritidis and S. Typhimurium. When Escherichia coli was used as the recipient strain, ROD21 transfer failed to be observed. Subsequently, we showed that a conjugative process was required for the transfer of the island and that changes in temperature and pH increased the transfer frequency between Salmonella strains. Our data indicate that ROD21 is an unstable pathogenicity island that can be transferred by conjugation in a species-specific manner between Salmonellae. Further, ROD21 transfer frequency increases in response to environmental changes, such as pH and temperature. PMID:24705125

Activated dynamics in dense fluids of attractive nonspherical particles. II. Elasticity, barriers, relaxation, fragility, and self-diffusion

NASA Astrophysics Data System (ADS)

Tripathy, Mukta; Schweizer, Kenneth S.

2011-04-01

In paper II of this series we apply the center-of-mass version of Nonlinear Langevin Equation theory to study how short-range attractive interactions influence the elastic shear modulus, transient localization length, activated dynamics, and kinetic arrest of a variety of nonspherical particle dense fluids (and the spherical analog) as a function of volume fraction and attraction strength. The activation barrier (roughly the natural logarithm of the dimensionless relaxation time) is predicted to be a rich function of particle shape, volume fraction, and attraction strength, and the dynamic fragility varies significantly with particle shape. At fixed volume fraction, the barrier grows in a parabolic manner with inverse temperature nondimensionalized by an onset value, analogous to what has been established for thermal glass-forming liquids. Kinetic arrest boundaries lie at significantly higher volume fractions and attraction strengths relative to their dynamic crossover analogs, but their particle shape dependence remains the same. A limited universality of barrier heights is found based on the concept of an effective mean-square confining force. The mean hopping time and self-diffusion constant in the attractive glass region of the nonequilibrium phase diagram is predicted to vary nonmonotonically with attraction strength or inverse temperature, qualitatively consistent with recent computer simulations and colloid experiments.

Identification and characterization of an Apis cerana cerana Delta class glutathione S-transferase gene ( AccGSTD) in response to thermal stress

NASA Astrophysics Data System (ADS)

Yan, Huiru; Jia, Haihong; Wang, Xiuling; Gao, Hongru; Guo, Xingqi; Xu, Baohua

2013-02-01

Glutathione S-transferases (GSTs) are members of a multifunctional enzyme super family that plays a pivotal role in both insecticide resistance and protection against oxidative stress. In this study, we identified a single-copy gene, AccGSTD, as being a Delta class GST in the Chinese honey bee ( Apis cerana cerana). A predicted antioxidant response element, CREB, was found in the 1,492-bp 5'-flanking region, suggesting that AccGSTD may be involved in oxidative stress response pathways. Real-time PCR and immunolocalization studies demonstrated that AccGSTD exhibited both developmental- and tissue-specific expression patterns. During development, AccGSTD transcript was increased in adults. The AccGSTD expression level was the highest in the honey bee brain. Thermal stress experiments demonstrated that AccGSTD could be significantly upregulated by temperature changes in a time-dependent manner. It is hypothesized that high expression levels might be due to the increased levels of oxidative stress caused by the temperature challenges. Additionally, functional assays of the recombinant AccGSTD protein revealed that AccGSTD has the capability to protect DNA from oxidative damage. Taken together, these data suggest that AccGSTD may be responsible for antioxidant defense in adult honey bees.

3D Printed Reversible Shape Changing Components with Stimuli Responsive Materials

NASA Astrophysics Data System (ADS)

Mao, Yiqi; Ding, Zhen; Yuan, Chao; Ai, Shigang; Isakov, Michael; Wu, Jiangtao; Wang, Tiejun; Dunn, Martin L.; Qi, H. Jerry

2016-04-01

The creation of reversibly-actuating components that alter their shapes in a controllable manner in response to environmental stimuli is a grand challenge in active materials, structures, and robotics. Here we demonstrate a new reversible shape-changing component design concept enabled by 3D printing two stimuli responsive polymers—shape memory polymers and hydrogels—in prescribed 3D architectures. This approach uses the swelling of a hydrogel as the driving force for the shape change, and the temperature-dependent modulus of a shape memory polymer to regulate the time of such shape change. Controlling the temperature and aqueous environment allows switching between two stable configurations - the structures are relatively stiff and can carry load in each - without any mechanical loading and unloading. Specific shape changing scenarios, e.g., based on bending, or twisting in prescribed directions, are enabled via the controlled interplay between the active materials and the 3D printed architectures. The physical phenomena are complex and nonintuitive, and so to help understand the interplay of geometric, material, and environmental stimuli parameters we develop 3D nonlinear finite element models. Finally, we create several 2D and 3D shape changing components that demonstrate the role of key parameters and illustrate the broad application potential of the proposed approach.

ClpC regulates the fate of a sporulation initiation sigma factor, sigmaH protein, in Bacillus subtilis at elevated temperatures.

PubMed

Nanamiya, H; Ohashi, Y; Asai, K; Moriya, S; Ogasawara, N; Fujita, M; Sadaie, Y; Kawamura, F

1998-07-01

Using a strain carrying a clpC-bgaB transcriptional fusion at the amyE locus, we found that the expression of a clpC operon was induced at the end of exponential growth in a sigmaB-independent manner and ceased around T3.5 in the wild type but not in a spo0H mutant. This suggests that some gene product(s) whose expression is dependent on sigmaH function is required for the turn-off of clpC transcription during an early stage of sporulation. A clpC deletion mutant showed a temperature-sensitive sporulation phenotype and exhibited an abnormally large accumulation of sigmaH in the cell at 45 degrees C after T2, at which time the sigmaH level in the wild type had begun to decrease. These results, together with the fact that spo0H transcription in the clpC deletion mutant was similar to that of the wild type, suggested that ClpC may be responsible for the degradation of sigmaH after the accomplishment of its role in sporulation. Moreover, as expected from these results, overproduction of Spo0A was also observed after the initiation of sporulation in the clpC deletion mutant at 45 degrees C.

Effects of rosuvastatin on the production and activation of matrix metalloproteinase-2 and migration of cultured rat vascular smooth muscle cells induced by homocysteine.

PubMed

Shi, Ya-fei; Chi, Ju-fang; Tang, Wei-liang; Xu, Fu-kang; Liu, Long-bin; Ji, Zheng; Lv, Hai-tao; Guo, Hang-yuan

2013-08-01

To test the influence of homocysteine on the production and activation of matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of matrix metalloproteinase-2 (TIMP-2) and on cell migration of cultured rat vascular smooth muscle cells (VSMCs). Also, to explore whether rosuvastatin can alter the abnormal secretion and activation of MMP-2 and TIMP-2 and migration of VSMCs induced by homocysteine. Rat VSMCs were incubated with different concentrations of homocysteine (50-5000 μmol/L). Western blotting and gelatin zymography were used to investigate the expressions and activities of MMP-2 and TIMP-2 in VSMCs in culture medium when induced with homocysteine for 24, 48, and 72 h. Transwell chambers were employed to test the migratory ability of VSMCs when incubated with homocysteine for 48 h. Different concentrations of rosuvastatin (10(-9)-10(-5) mol/L) were added when VSMCs were induced with 1000 μmol/L homocysteine. The expressions and activities of MMP-2 and TIMP-2 were examined after incubating for 24, 48, and 72 h, and the migration of VSMCs was also examined after incubating for 48 h. Homocysteine (50-1000 μmol/L) increased the production and activation of MMP-2 and expression of TIMP-2 in a dose-dependent manner. However, when incubated with 5000 μmol/L homocysteine, the expression of MMP-2 was up-regulated, but its activity was down-regulated. Increased homocysteine-induced production and activation of MMP-2 were reduced by rosuvastatin in a dose-dependent manner whereas secretion of TIMP-2 was not significantly altered by rosuvastatin. Homocysteine (50-5000 μmol/L) stimulated the migration of VSMCs in a dose-dependent manner, but this effect was eliminated by rosuvastatin. Homocysteine (50-1000 μmol/L) significantly increased the production and activation of MMP-2, the expression of TIMP-2, and the migration of VSMCs in a dose-dependent manner. Additional extracellular rosuvastatin can decrease the excessive expression and activation of MMP-2 and abnormal migration of VSMCs induced by homocysteine.

A Programmable Optical Stimulator for the Drosophila Eye.

PubMed

Chen, Xinping; Leon-Salas, Walter D; Zigon, Taylor; Ready, Donald F; Weake, Vikki M

2017-10-01

A programmable optical stimulator for Drosophila eyes is presented. The target application of the stimulator is to induce retinal degeneration in fly photoreceptor cells by exposing them to light in a controlled manner. The goal of this work is to obtain a reproducible system for studying age-related changes in susceptibility to environmental ocular stress. The stimulator uses light emitting diodes and an embedded computer to control illuminance, color (blue or red) and duration in two independent chambers. Further, the stimulator is equipped with per-chamber light and temperature sensors and a fan to monitor light intensity and to control temperature. An ON/OFF temperature control implemented on the embedded computer keeps the temperature from reaching levels that will induce the heat shock stress response in the flies. A custom enclosure was fabricated to house the electronic components of the stimulator. The enclosure provides a light-impermeable environment that allows air flow and lets users easily load and unload fly vials. Characterization results show that the fabricated stimulator can produce light at illuminances ranging from 0 to 16000 lux and power density levels from 0 to 7.2 mW/cm 2 for blue light. For red light the maximum illuminance is 8000 lux which corresponds to a power density of 3.54 mW/cm 2 . The fans and the ON/OFF temperature control are able to keep the temperature inside the chambers below 28.17°C. Experiments with white-eye male flies were performed to assess the ability of the fabricated simulator to induce blue light-dependent retinal degeneration. Retinal degeneration is observed in flies exposed to 8 hours of blue light at 7949 lux. Flies in a control experiment with no light exposure show no retinal degeneration. Flies exposed to red light for the similar duration and light intensity (8 hours and 7994 lux) do not show retinal degeneration either. Hence, the fabricated stimulator can be used to create environmental ocular stress using blue light.

The temperature dependence of optical properties of tungsten in the visible and near-infrared domains: an experimental and theoretical study

NASA Astrophysics Data System (ADS)

Minissale, Marco; Pardanaud, Cedric; Bisson, Régis; Gallais, Laurent

2017-11-01

The knowledge of optical properties of tungsten at high temperatures is of crucial importance in fields such as nuclear fusion and aerospace applications. The optical properties of tungsten are well known at room temperature, but little has been done at temperatures between 300 K and 1000 K in the visible and near-infrared domains. Here, we investigate the temperature dependence of tungsten reflectivity from the ambient to high temperatures (<1000 K) in the 500-1050 nm spectral range, a region where interband transitions make a strong contribution. Experimental measurements, performed via a spectroscopic system coupled with laser remote heating, show that tungsten’s reflectivity increases with temperature and wavelength. We have described these dependences through a Fresnel and two Lorentz-Drude models. The Fresnel model accurately reproduces the experimental curve at a given temperature, but it is able to simulate the temperature dependency of reflectivity only thanks to an ad hoc choice of temperature formulae for the refractive indexes. Thus, a less empirical approach, based on Lorentz-Drude models, is preferred to describe the interaction of light and charge carriers in the solid. The first Lorentz-Drude model, which includes a temperature dependency on intraband transitions, fits experimental results only qualitatively. The second Lorentz-Drude model includes in addition a temperature dependency on interband transitions. It is able to reproduce the experimental results quantitatively, highlighting a non-trivial dependence of interband transitions as a function of temperature. Eventually, we use these temperature dependent Lorentz-Drude models to evaluate the total emissivity of tungsten from 300 K to 3500 K, and we compare our experimental and theoretical findings with previous results.

Investigation of moisture-induced embrittlement of iron aluminides. Interim report

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

Castagna, A.; Stoloff, N.S.

Alloy FA-129 undergoes an increase in crack propagation rate and a loss of fracture toughness in moisture-bearing and hydrogen gas environments. A similar effect is seen on ductility of FA-129 in tensile tests. The embrittling effect in air is attributed to oxidation of aluminum in the alloy by water vapor to produce Al{sub 2}O{sub 3} and hydrogen gas. Alloy FAP-Y, which is disordered and contains only 16 a%Al is embrittled by hydrogen gas in a manner similar to that of FA-129. However, laboratory air had little effect on the crack growth rates, fracture toughness, or tensile ductility. The lower aluminummore » content apparently is insufficient to induce the Al-H{sub 2}O reaction. TEM and SEM analyses of microstructure and fracture surfaces were consistent with the change in fracture toughness with order and environment. Testing at elevated temperatures reduces crack growth rates in FA-129, and increases fracture toughness and ductility. This is consistent with the well documented peak in hydrogen embrittlement in structural alloys at or near room temperature. Elevated temperature affects the degree of embrittlement in a complex manner, possibly changing the rates of several of the processes involved.« less

Molecular players involved in temperature-dependent sex determination and sex differentiation in Teleost fish

PubMed Central

2014-01-01

The molecular mechanisms that underlie sex determination and differentiation are conserved and diversified. In fish species, temperature-dependent sex determination and differentiation seem to be ubiquitous and molecular players involved in these mechanisms may be conserved. Although how the ambient temperature transduces signals to the undifferentiated gonads remains to be elucidated, the genes downstream in the sex differentiation pathway are shared between sex-determining mechanisms. In this paper, we review recent advances on the molecular players that participate in the sex determination and differentiation in fish species, by putting emphasis on temperature-dependent sex determination and differentiation, which include temperature-dependent sex determination and genetic sex determination plus temperature effects. Application of temperature-dependent sex differentiation in farmed fish and the consequences of temperature-induced sex reversal are discussed. PMID:24735220

Vertical resolving power of a satellite temperature sounding system

NASA Technical Reports Server (NTRS)

Thompson, O. E.

1979-01-01

The paper examines the vertical resolving power of satellite temperature retrieval systems. Attention is given to sounding instrument proposed by Kaplan, et al., (1977) which has been conceived to have greatly improved vertical resolving capabilities. Two types of tests are reported. The first, based on the work of Conrath (1972), involves a theoretical assessment of the manner by which the ambient temperature profile is averaged over height in order to produce an estimate of temperature at a given level. The second test is empirical involving the actual retrieval of temperature signals superimposed on a standard atmosphere with an emphasis on determining the minimum separation of the signals for which the sounder system is still capable of distinguishing individual signals.

Rare Earth Doped High Temperature Ceramic Selective Emitters

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Pal, AnnaMarie; Patton, Martin O.; Jenkins, Phillip P.

1999-01-01

As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study develops a spectral emittance model for films of rare earth containing materials. Although there are several possible rare earth doped high temperature materials, this study was confined to rare earth aluminum garnets. Good agreement between experimental and theoretical spectral emittances was found for erbium, thulium and erbium-holmium aluminum garnets. Spectral emittances of these films are sensitive to temperature differences across the film. Emitter efficiency is also a sensitive function of temperature. For thulium aluminum garnet the efficiency is 0.38 at 1700 K but only 0.19 at 1262 K.

PARTICLE ACCELERATOR AND METHOD OF CONTROLLING THE TEMPERATURE THEREOF

DOEpatents

Neal, R.B.; Gallagher, W.J.

1960-10-11

A method and means for controlling the temperature of a particle accelerator and more particularly to the maintenance of a constant and uniform temperature throughout a particle accelerator is offered. The novel feature of the invention resides in the provision of two individual heating applications to the accelerator structure. The first heating application provided is substantially a duplication of the accelerator heat created from energization, this first application being employed only when the accelerator is de-energized thereby maintaining the accelerator temperature constant with regard to time whether the accelerator is energized or not. The second heating application provided is designed to add to either the first application or energization heat in a manner to create the same uniform temperature throughout all portions of the accelerator.

Genotoxicity of dill (Anethum graveolens L.), peppermint (Menthaxpiperita L.) and pine (Pinus sylvestris L.) essential oils in human lymphocytes and Drosophila melanogaster.

PubMed

Lazutka, J R; Mierauskiene, J; Slapsyte, G; Dedonyte, V

2001-05-01

Genotoxic properties of the essential oils extracted from dill (Anethum graveolens L.) herb and seeds, peppermint (Menthaxpiperita L.) herb and pine (Pinus sylvestris L.) needles were studied using chromosome aberration (CA) and sister chromatid exchange (SCE) tests in human lymphocytes in vitro, and Drosophila melanogaster somatic mutation and recombination test (SMART) in vivo. In the CA test, the most active essential oil was from dill seeds, then followed essential oils from dill herb, peppermint herb and pine needles, respectively. In the SCE test, the most active essential oils were from dill herb and seeds followed by essential oils from pine needles and peppermint herb. Essential oils from dill herb and seeds and pine needles induced CA and SCE in a clear dose-dependent manner, while peppermint essential oil induced SCE in a dose-independent manner. All essential oils were cytotoxic for human lymphocytes. In the SMART test, a dose-dependent increase in mutation frequency was observed for essential oils from pine and dill herb. Peppermint essential oil induced mutations in a dose-independent manner. Essential oil from dill seeds was almost inactive in the SMART test.

Phosphoproteomics analyses show subnetwork systems in T-cell receptor signaling.

PubMed

Hatano, Atsushi; Matsumoto, Masaki; Nakayama, Keiichi I

2016-10-01

A key issue in the study of signal transduction is how multiple signaling pathways are systematically integrated into the cell. We have now performed multiple phosphoproteomics analyses focused on the dynamics of the T-cell receptor (TCR) signaling network and its subsystem mediated by the Ca 2+ signaling pathway. Integration of these phosphoproteomics data sets and extraction of components of the TCR signaling network dependent on Ca 2+ signaling showed unexpected phosphorylation kinetics for candidate substrates of the Ca 2+ -dependent phosphatase calcineurin (CN) during TCR stimulation. Detailed characterization of the TCR-induced phosphorylation of a novel CN substrate, Itpkb, showed that phosphorylation of this protein is regulated by both CN and the mitogen-activated protein kinase Erk in a competitive manner. Phosphorylation of additional CN substrates was also found to be regulated by Erk and CN in a similar manner. The combination of multiple phosphoproteomics approaches thus showed two major subsystems mediated by Erk and CN in the TCR signaling network, with these subsystems regulating the phosphorylation of a group of proteins in a competitive manner. © 2016 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

Adiponectin inhibits leptin-induced oncogenic signalling in oesophageal cancer cells by activation of PTP1B.

PubMed

Beales, Ian L P; Garcia-Morales, Carla; Ogunwobi, Olorunseun O; Mutungi, Gabriel

2014-01-25

Obesity is characterised by hyperleptinaemia and hypoadiponectinaemia and these metabolic abnormalities may contribute to the progression of several obesity-associated cancers including oesophageal adenocarcinoma (OAC). We have examined the effects of leptin and adiponectin on OE33 OAC cells. Leptin stimulated proliferation, invasion and migration and inhibited apoptosis in a STAT3-dependant manner. Leptin-stimulated MMP-2 secretion in a partly STAT3-dependent manner and MMP-9 secretion via a STAT3-independent pathway. Adiponectin inhibited leptin-induced proliferation, migration, invasion, MMP secretion and reduced the anti-apoptotic effects: these effects of adiponectin were ameliorated by both a non-specific tyrosine phosphatase inhibitor and a specific PTP1B inhibitor. Adiponectin reduced leptin-stimulated JAK2 activation and STAT3 transcriptional activity in a PTP1B-sensitive manner and adiponectin increased both PTP1B protein and activity. We conclude that adiponectin restrains leptin-induced signalling and pro-carcinogenic behaviour by inhibiting the early events in leptin-induced signal transduction by activating PTP1B. Relative adiponectin deficiency in obesity may contribute to the promotion of OAC. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Host- and stage-dependent secretome of the arbuscular mycorrhizal fungus Rhizophagus irregularis.

PubMed

Zeng, Tian; Holmer, Rens; Hontelez, Jan; Te Lintel-Hekkert, Bas; Marufu, Lucky; de Zeeuw, Thijs; Wu, Fangyuan; Schijlen, Elio; Bisseling, Ton; Limpens, Erik

2018-05-01

Arbuscular mycorrhizal fungi form the most wide-spread endosymbiosis with plants. There is very little host specificity in this interaction, however host preferences as well as varying symbiotic efficiencies have been observed. We hypothesize that secreted proteins (SPs) may act as fungal effectors to control symbiotic efficiency in a host-dependent manner. Therefore, we studied whether arbuscular mycorrhizal (AM) fungi adjust their secretome in a host- and stage-dependent manner to contribute to their extremely wide host range. We investigated the expression of SP-encoding genes of Rhizophagus irregularis in three evolutionary distantly related plant species, Medicago truncatula, Nicotiana benthamiana and Allium schoenoprasum. In addition we used laser microdissection in combination with RNA-seq to study SP expression at different stages of the interaction in Medicago. Our data indicate that most expressed SPs show roughly equal expression levels in the interaction with all three host plants. In addition, a subset shows significant differential expression depending on the host plant. Furthermore, SP expression is controlled locally in the hyphal network in response to host-dependent cues. Overall, this study presents a comprehensive analysis of the R. irregularis secretome, which now offers a solid basis to direct functional studies on the role of fungal SPs in AM symbiosis. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

Leucine facilitates insulin signaling through a Gαi protein-dependent signaling pathway in hepatocytes.

PubMed

Yang, Xuefeng; Mei, Shuang; Wang, Xiaolei; Li, Xiang; Liu, Rui; Ma, Yan; Hao, Liping; Yao, Ping; Liu, Liegang; Sun, Xiufa; Gu, Haihua; Liu, Zhenqi; Cao, Wenhong

2013-03-29

In this study, we addressed the direct effect of leucine on insulin signaling. In investigating the associated mechanisms, we found that leucine itself does not activate the classical Akt- or ERK1/2 MAP kinase-dependent signaling pathways but can facilitate the insulin-induced phosphorylations of Akt(473) and ERK1/2 in a time- and dose-dependent manner in cultured hepatocytes. The leucine-facilitated insulin-induced phosphorylation of Akt at residue 473 was not affected by knocking down the key component of mTORC1 or -2 complexes but was blocked by inhibition of c-Src (PP2), PI3K (LY294002), Gαi protein (pertussis toxin or siRNA against Gαi1 gene, or β-arrestin 2 (siRNA)). Similarly, the leucine-facilitated insulin activation of ERK1/2 was also blunted by pertussis toxin. We further show that leucine facilitated the insulin-mediated suppression of glucose production and expression of key gluconeogenic genes in a Gαi1 protein-dependent manner in cultured primary hepatocytes. Together, these results show that leucine can directly facilitate insulin signaling through a Gαi protein-dependent intracellular signaling pathway. This is the first evidence showing that macronutrients like amino acid leucine can facilitate insulin signaling through G proteins directly.

Leucine Facilitates Insulin Signaling through a Gαi Protein-dependent Signaling Pathway in Hepatocytes*

PubMed Central

Yang, Xuefeng; Mei, Shuang; Wang, Xiaolei; Li, Xiang; Liu, Rui; Ma, Yan; Hao, Liping; Yao, Ping; Liu, Liegang; Sun, Xiufa; Gu, Haihua; Liu, Zhenqi; Cao, Wenhong

2013-01-01

In this study, we addressed the direct effect of leucine on insulin signaling. In investigating the associated mechanisms, we found that leucine itself does not activate the classical Akt- or ERK1/2 MAP kinase-dependent signaling pathways but can facilitate the insulin-induced phosphorylations of Akt473 and ERK1/2 in a time- and dose-dependent manner in cultured hepatocytes. The leucine-facilitated insulin-induced phosphorylation of Akt at residue 473 was not affected by knocking down the key component of mTORC1 or -2 complexes but was blocked by inhibition of c-Src (PP2), PI3K (LY294002), Gαi protein (pertussis toxin or siRNA against Gαi1 gene, or β-arrestin 2 (siRNA)). Similarly, the leucine-facilitated insulin activation of ERK1/2 was also blunted by pertussis toxin. We further show that leucine facilitated the insulin-mediated suppression of glucose production and expression of key gluconeogenic genes in a Gαi1 protein-dependent manner in cultured primary hepatocytes. Together, these results show that leucine can directly facilitate insulin signaling through a Gαi protein-dependent intracellular signaling pathway. This is the first evidence showing that macronutrients like amino acid leucine can facilitate insulin signaling through G proteins directly. PMID:23404499

Hydrothermal carbonization of livestock mortality for the reduction of pathogens and microbially-derived DNA

USDA-ARS?s Scientific Manuscript database

Hydrothermal carbonization (HTC), utilizing high temperature and pressure, has the potential to treat agricultural waste and inactivate pathogens, antibiotic resistance genes (ARG), and contaminants of emerging concern (CEC) in an environmentally and economically friendly manner. Livestock mortality...

9 CFR 318.307 - Record review and maintenance.

Code of Federal Regulations, 2013 CFR

2013-01-01

... temperature/time recording devices shall be identified by production date, container code, processing vessel... made available to Program employees for review. (b) Automated process monitoring and recordkeeping. Automated process monitoring and recordkeeping systems shall be designed and operated in a manner that will...

9 CFR 318.307 - Record review and maintenance.

Code of Federal Regulations, 2012 CFR

2012-01-01

... temperature/time recording devices shall be identified by production date, container code, processing vessel... made available to Program employees for review. (b) Automated process monitoring and recordkeeping. Automated process monitoring and recordkeeping systems shall be designed and operated in a manner that will...

9 CFR 318.307 - Record review and maintenance.

Code of Federal Regulations, 2014 CFR

2014-01-01

... temperature/time recording devices shall be identified by production date, container code, processing vessel... made available to Program employees for review. (b) Automated process monitoring and recordkeeping. Automated process monitoring and recordkeeping systems shall be designed and operated in a manner that will...

9 CFR 318.307 - Record review and maintenance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... temperature/time recording devices shall be identified by production date, container code, processing vessel... made available to Program employees for review. (b) Automated process monitoring and recordkeeping. Automated process monitoring and recordkeeping systems shall be designed and operated in a manner that will...

9 CFR 318.307 - Record review and maintenance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... temperature/time recording devices shall be identified by production date, container code, processing vessel... made available to Program employees for review. (b) Automated process monitoring and recordkeeping. Automated process monitoring and recordkeeping systems shall be designed and operated in a manner that will...

49 CFR 238.231 - Brake system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... section, “unattended equipment” means equipment left standing and unmanned in such a manner that the brake... wheels or disc rotor surface temperatures exceeding the manufacturer's recommendation. (k) For new... equipment operating speeds. A new simulation is required prior to implementing a change in operating...

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.

Theoretical temperature-dependent branching ratios and laser thresholds of the 3F4 to 3H6 levels of Tm(3+) in ten garnets

NASA Technical Reports Server (NTRS)

Filer, Elizabeth D.; Barnes, Norman P.; Morrison, Clyde A.

1991-01-01

The calculated energy levels, the branching ratios, and the estimated thresholds for thulium operating on the 3F4 to 3H6 transitions are reported. Garnet materials with the general formula A3B2C3O12 are evaluated. Calculations are performed for the A side under the assumption of D2 symmetry. X-ray data available in the literature are used to evaluate the crystal-field components, A sub nm. Even-n components are employed to calculate the crystal-field splittings within the manifold. Thermal occupation factors are determined in a straightforward manner using a Boltzmann distribution for the respective manifolds. Odd-n components are applied to calculate the transition probabilities for electric field transitions. It is determined that the magnetic dipole contributions to the transition probability are comparable to the electric dipole contributions in some cases. Thresholds as a function of the density of thulium atoms are calculated.

Adhesive Leaf Created by a Corona Discharge.

PubMed

Lee, Wonseok; Son, Jongsang; Kim, Seonghyun; Yang, Dongmin; Choi, Seungyeop; Watanabe, Rodrigo Akira; Hwang, Kyo Seon; Lee, Sang Woo; Lee, Gyudo; Yoon, Dae Sung

2018-01-29

Here, we report a new concept of both the adhesive manner and material, named "adhesive leaf (AL)," based on the leaf of the plant Heteropanax fragrans. The treatment of the corona discharge on the leaf surface can cause the nano-/microdestruction of the leaf epidermis, resulting in an outward release of sap. The glucose-containing sap provided the AL with a unique ability to stick to various substrates such as steel, polypropylene, and glass. Moreover, we reveal that the AL adhesion strength depends on the AL size, as well as the corona-discharge intensity. Conventional adhesives, such as glue and bond, lose their adhesive property and leave dirty residues upon the removal of the attached material. Unlike the conventional methods, the AL is advantageous as it can be repeatedly attached and detached thoroughly until the sap liquid is exhausted; its adhesive ability is maintained for at least three weeks at room temperature. Our findings shed light on a new concept of a biodegradable adhesive material that is created by a simple surface treatment.

Magnetic and neutron diffraction study on quaternary oxides MTeMoO6 (M = Mn and Zn)

NASA Astrophysics Data System (ADS)

Doi, Yoshihiro; Suzuki, Ryo; Hinatsu, Yukio; Ohoyama, Kenji

2009-01-01

Crystal structures and magnetic properties of quaternary oxides MTeMoO6 (M = Mn and Zn) were investigated. From the Rietveld analyses for the powder x-ray and neutron diffraction measurements, their detailed structures have been determined. Both compounds have orthorhombic structure with space group P 21212 and a charge configuration of M2+Te4+Mo6+O6. ZnTeMoO6 shows diamagnetic behavior. In this structure, M ions are arranged in a square-planar manner. The temperature dependence of the magnetic susceptibility for MnTeMoO6 shows a broad peak at ~33 K, which is due to a two-dimensional characteristic of the magnetic interaction. In addition, this compound shows an antiferromagnetic transition at 20 K. The magnetic structure was determined by the powder neutron diffraction measurement at 3.3 K. The magnetic moments of Mn2+ ions (4.45 μB) order in a collinear antiferromagnetic arrangement along the b axis.

Epitaxy: Programmable Atom Equivalents Versus Atoms

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

Wang, Mary X.; Seo, Soyoung E.; Gabrys, Paul A.

The programmability of DNA makes it an attractive structure-directing ligand for the assembly of nanoparticle superlattices in a manner that mimics many aspects of atomic crystallization. However, the synthesis of multilayer single crystals of defined size remains a challenge. Though previous studies considered lattice mismatch as the major limiting factor for multilayer assembly, thin film growth depends on many interlinked variables. Here, a more comprehensive approach is taken to study fundamental elements, such as the growth temperature and the thermodynamics of interfacial energetics, to achieve epitaxial growth of nanoparticle thin films. Under optimized equilibrium conditions, single crystal, multilayer thin filmsmore » can be synthesized over 500 × 500 μm2 areas on lithographically patterned templates. Importantly, these superlattices follow the same patterns of crystal growth demonstrated in thin film atomic deposition, allowing for these processes to be understood in the context of well-studied atomic epitaxy, and potentially enabling a nanoscale model to study fundamental crystallization processes.« less

In vitro pharmacokinetics of phosphorothioate antisense oligonucleotides.

PubMed

Crooke, R M; Graham, M J; Cooke, M E; Crooke, S T

1995-10-01

ISIS 2105 (Afovirsen), a 20-mer phosphorothioate oligonucleotide that inhibits the production of a gene product essential to the growth of human papillomavirus, is in phase II clinical trials for the treatment of genital warts induced by human papillomavirus-6 and human papillomavirus-11. The uptake, subcellular distribution and metabolism of ISIS 2105 and three other similar length phosphorothioates have been studied in a variety of cell lines. Our experiments indicated that ISIS 2105 and other phosphorothioates are internalized and distributed in a time-, temperature-, concentration-, sequence- and cell line-dependent manner. Cell association was also influenced by the tissue culture medium. Several different analytical techniques revealed that phosphorothioates were more rapidly degraded in vitro than previously reported. These data suggest that phosphorothioate oligonucleotide uptake and stability observed in tissue culture can vary as a function of cellular assay conditions and analytical methods used. Comparison of these results with those obtained in vivo suggests that the pharmacokinetic behavior of this class of compounds cannot necessarily be predicted from in vitro studies.

The Ionotropic Receptors IR21a and IR25a mediate cool sensing in Drosophila

PubMed Central

Ni, Lina; Klein, Mason; Svec, Kathryn V; Budelli, Gonzalo; Chang, Elaine C; Ferrer, Anggie J; Benton, Richard; Samuel, Aravinthan DT; Garrity, Paul A

2016-01-01

Animals rely on highly sensitive thermoreceptors to seek out optimal temperatures, but the molecular mechanisms of thermosensing are not well understood. The Dorsal Organ Cool Cells (DOCCs) of the Drosophila larva are a set of exceptionally thermosensitive neurons critical for larval cool avoidance. Here, we show that DOCC cool-sensing is mediated by Ionotropic Receptors (IRs), a family of sensory receptors widely studied in invertebrate chemical sensing. We find that two IRs, IR21a and IR25a, are required to mediate DOCC responses to cooling and are required for cool avoidance behavior. Furthermore, we find that ectopic expression of IR21a can confer cool-responsiveness in an Ir25a-dependent manner, suggesting an instructive role for IR21a in thermosensing. Together, these data show that IR family receptors can function together to mediate thermosensation of exquisite sensitivity. DOI: http://dx.doi.org/10.7554/eLife.13254.001 PMID:27126188

Development of a flameproof elastic elastomeric fiber

NASA Technical Reports Server (NTRS)

Howarth, J. T.; Nilgrom, J.; Massucco, A.; Sheth, S. G.; Dawn, F. S.

1971-01-01

Various flexible polyurethane structures containing halogen were synthesized from polyesters derived from aliphatic or aromatic polyols and dibasic acids. Aliphatic halide structures could not be used because they are unstable at the required reaction temperatures, giving of hydrogen halide which hydrolyzes the ester linkages. In contract, halogen-containing aromatic polyols were stable and satisfactory products were made. The most promising composition, a brominated neopentyl glycol capped with toluene disocyanate, was used as a conventional diisocyanate, in conjunction with hydroxy-terminated polyethers or polyesters to form elastomeric urethanes containing about 10% bromine with weight. Products made in this manner will not burn in air, have an oxygen index value of about 25, and have tensile strength values of about 5,000 psi at 450% elongation. The most efficient additives for imparting flame retardancy to Spandex urethanes are aromatic halides and the most effective of these are the bromide compounds. Various levels of flame retardancy have been achieved depending on the levels of additives used.

Heat-induced Irreversible Denaturation of the Camelid Single Domain VHH Antibody Is Governed by Chemical Modifications

PubMed Central

Akazawa-Ogawa, Yoko; Takashima, Mizuki; Lee, Young-Ho; Ikegami, Takahisa; Goto, Yuji; Uegaki, Koichi; Hagihara, Yoshihisa

2014-01-01

The variable domain of camelid heavy chain antibody (VHH) is highly heat-resistant and is therefore ideal for many applications. Although understanding the process of heat-induced irreversible denaturation is essential to improve the efficacy of VHH, its inactivation mechanism remains unclear. Here, we showed that chemical modifications predominantly governed the irreversible denaturation of VHH at high temperatures. After heat treatment, the activity of VHH was dependent only on the incubation time at 90 °C and was insensitive to the number of heating (90 °C)-cooling (20 °C) cycles, indicating a negligible role for folding/unfolding intermediates on permanent denaturation. The residual activity was independent of concentration; therefore, VHH lost its activity in a unimolecular manner, not by aggregation. A VHH mutant lacking Asn, which is susceptible to chemical modifications, had significantly higher heat resistance than did the wild-type protein, indicating the importance of chemical modifications to VHH denaturation. PMID:24739391

Controlled release of therapeutics using interpenetrating polymeric networks.

PubMed

Aminabhavi, Tejraj M; Nadagouda, Mallikarjuna N; More, Uttam A; Joshi, Shrinivas D; Kulkarni, Venkatrao H; Noolvi, Malleshappa N; Kulkarni, Padmakar V

2015-04-01

The ever-increasing developments in pharmaceutical formulations have led to the widespread use of biodegradable polymers in various forms and configurations. In particular, interpenetrating network (IPN) and semi-IPN polymer structures that are capable of releasing drugs in a controlled manner have gained much wider importance in recent years. Recently, IPNs and semi-IPNs have emerged as innovative materials of choice in controlled release (CR) of drugs as the release from these systems depends on pH of the media and temperature in addition to the nature of the system. These networks can be prepared as smart hydrogels following chemical or physical crosslinking methods to show remarkable drug release patterns compared to single polymer systems. A large number of IPNs and semi-IPNs have been reported in the literature. The present review is focused on the preparation methods and their CR properties with reference to anticancer, anti-asthmatic, antibiotic, anti-inflammatory, anti-tuberculosis and antihypertensive drugs, as majority of these drugs have been reported to be the ideal choices for using IPNs and semi-IPNs.

Attenuation of methamphetamine-induced nigrostriatal dopaminergic neurotoxicity in mice by lipopolysaccharide pretreatment.

PubMed

Lin, Yin Chiu; Kuo, Yu-Min; Liao, Pao-Chi; Cherng, Chianfang G; Su, Su-Wen; Yu, Lung

2007-04-30

Immunological activation has been proposed to play a role in methamphetamine-induced dopaminergic terminal damage. In this study, we examined the roles of lipopolysaccharide, a pro-inflammatory and inflammatory factor, treatment in modulating the methamphetamine-induced nigrostriatal dopamine neurotoxicity. Lipopolysaccharide pretreatment did not affect the basal body temperature or methamphetamine-elicited hyperthermia three days later. Such systemic lipopolysaccharide treatment mitigated methamphetamine-induced striatal dopamine and 3,4-dihydroxyphenylacetic acid depletions in a dose-dependent manner. As the most potent dose (1 mg/kg) of lipopolysaccharide was administered two weeks, one day before or after the methamphetamine dosing regimen, methamphetamine-induced striatal dopamine and 3,4-dihydroxyphenylacetic acid depletions remained unaltered. Moreover, systemic lipopolysaccharide pretreatment (1 mg/kg) attenuated local methamphetamine infusion-produced dopamine and 3,4-dihydroxyphenylacetic acid depletions in the striatum, indicating that the protective effect of lipopolysaccharide is less likely due to interrupted peripheral distribution or metabolism of methamphetamine. We concluded a critical time window for systemic lipopolysaccharide pretreatment in exerting effective protection against methamphetamine-induced nigrostriatal dopamine neurotoxicity.

Metal chelate affinity precipitation of RNA and purification of plasmid DNA

NASA Technical Reports Server (NTRS)

Balan, Sindhu; Murphy, Jason; Galaev, Igor; Kumar, Ashok; Fox, George E.; Mattiasson, Bo; Willson, Richard C.

2003-01-01

The affinity of metal chelates for amino acids, such as histidine, is widely used in purifying proteins, most notably through six-histidine 'tails'. We have found that metal affinity interactions can also be applied to separation of single-stranded nucleic acids through interactions involving exposed purines. Here we describe a metal affinity precipitation method to resolve RNA from linear and plasmid DNA. A copper-charged copolymer of N-isopropyl acrylamide (NIPAM) and vinyl imidazole (VI) is used to purify plasmid from an alkaline lysate of E. coli. The NIPAM units confer reversible solubility on the copolymer while the imidazole chelates metal ions in a manner accessible to interaction with soluble ligands. RNA was separated from the plasmid by precipitation along with the polymer in the presence of 800 mM NaCl. Bound RNA could be recovered by elution with imidazole and separated from copolymer by a second precipitation step. RNA binding showed a strong dependence on temperature and on the type of buffer used.

Disruption of Phosphatidylcholine Monolayers and Bilayers by Perfluorobutane Sulfonate

PubMed Central

Oldham, E. Davis; Xie, Wei; Farnoud, Amir M.; Fiegel, Jennifer; Lehmler, Hans-Joachim

2012-01-01

Perfluoroalkyl acids (PFAAs) are persistent environmental contaminants resistant to biological and chemical degradation due to the presence of carbon-fluorine bonds. These compounds exhibit developmental toxicity in vitro and in vivo. The mechanisms of toxicity may involve partitioning into lipid bilayers. We investigated the interaction between perfluorobutane sulfonate (PFBS), an emerging PFAA, and model phosphatidylcholine (PC) lipid assemblies (i.e., dimyristoyl-, dipalmitoyl- and distearylphosphatidylcholine) using fluorescence anisotropy and Langmuir monolayer techniques. PFBS decreased the transition temperature and transition width of PC bilayers. The apparent membrane partition coefficients ranged from 4.9 × 102 to 8.2 × 102. The effects on each PC were comparable. The limiting molecular area of PC monolayers increased and the surface pressure at collapse decreased in a concentration-dependent manner. The compressibility of all three PCs was decreased by PFBS. In summary, PFBS disrupted different model lipid assemblies indicating potential for PFBS to be a human toxicant. However the effects of PFBS are not as pronounced as those seen with longer chain PFAAs. PMID:22834732

A new model for in situ nitrogen incorporation into 4H-SiC during epitaxy

PubMed Central

Ferro, Gabriel; Chaussende, Didier

2017-01-01

Nitrogen doping of 4H-SiC during vapor phase epitaxy is still lacking of a general model explaining the apparently contradictory trends obtained by different teams. In this paper, the evolutions of nitrogen incorporation (on both polar Si and C faces) as a function of the main growth parameters (C/Si ratio, temperature, pressure and growth rate) are reviewed and explained using a model based on surface exchanges between the gas phase and the uppermost 4H-SiC atomic layers. In this model, N incorporation is driven mainly by the transient formation of C vacancies, due to H2 etching, at the surface or near the surface. It is shown that all the growth parameters are influencing the probability of C vacancies formation in a similar manner as they do for N incorporation. The surface exchange model proposes a new framework for explaining the experimental results even beyond the commonly accepted reactor type dependency. PMID:28211528

Antiviral effects of artesunate on polyomavirus BK replication in primary human kidney cells.

PubMed

Sharma, Biswa Nath; Marschall, Manfred; Henriksen, Stian; Rinaldo, Christine Hanssen

2014-01-01

Polyomavirus BK (BKV) causes polyomavirus-associated nephropathy (PyVAN) and hemorrhagic cystitis (PyVHC) in renal and bone marrow transplant patients, respectively. Antiviral drugs with targeted activity against BKV are lacking. Since the antimalarial drug artesunate was recently demonstrated to have antiviral activity, the possible effects of artesunate on BKV replication in human primary renal proximal tubular epithelial cells (RPTECs), the host cells in PyVAN, were explored. At 2 h postinfection (hpi), RPTECs were treated with artesunate at concentrations ranging from 0.3 to 80 μM. After one viral replication cycle (approximately 72 hpi), the loads of extracellular BKV DNA, reflecting viral progeny production, were reduced in a concentration-dependent manner. Artesunate at 10 μM reduced the extracellular BKV load by 65%; early large T antigen mRNA and protein expression by 30% and 75%, respectively; DNA replication by 73%; and late VP1 mRNA and protein expression by 47% and 64%, respectively. Importantly, the proliferation of RPTECs was also inhibited in a concentration-dependent manner. At 72 hpi, artesunate at 10 μM reduced cellular DNA replication by 68% and total metabolic activity by 47%. Cell impedance and lactate dehydrogenase measurements indicated a cytostatic but not a cytotoxic mechanism. Flow cytometry and 5-ethynyl-2'-deoxyuridine incorporation revealed a decreased number of cells in S phase and suggested cell cycle arrest in G0 or G2 phase. Both the antiproliferative and antiviral effects of artesunate at 10 μM were reversible. Thus, artesunate inhibits BKV replication in RPTECs in a concentration-dependent manner by inhibiting BKV gene expression and genome replication. The antiviral mechanism appears to be closely connected to cytostatic effects on the host cell, underscoring the dependence of BKV on host cell proliferative functions.

Antiviral Effects of Artesunate on Polyomavirus BK Replication in Primary Human Kidney Cells

PubMed Central

Sharma, Biswa Nath; Marschall, Manfred; Henriksen, Stian

2014-01-01

Polyomavirus BK (BKV) causes polyomavirus-associated nephropathy (PyVAN) and hemorrhagic cystitis (PyVHC) in renal and bone marrow transplant patients, respectively. Antiviral drugs with targeted activity against BKV are lacking. Since the antimalarial drug artesunate was recently demonstrated to have antiviral activity, the possible effects of artesunate on BKV replication in human primary renal proximal tubular epithelial cells (RPTECs), the host cells in PyVAN, were explored. At 2 h postinfection (hpi), RPTECs were treated with artesunate at concentrations ranging from 0.3 to 80 μM. After one viral replication cycle (approximately 72 hpi), the loads of extracellular BKV DNA, reflecting viral progeny production, were reduced in a concentration-dependent manner. Artesunate at 10 μM reduced the extracellular BKV load by 65%; early large T antigen mRNA and protein expression by 30% and 75%, respectively; DNA replication by 73%; and late VP1 mRNA and protein expression by 47% and 64%, respectively. Importantly, the proliferation of RPTECs was also inhibited in a concentration-dependent manner. At 72 hpi, artesunate at 10 μM reduced cellular DNA replication by 68% and total metabolic activity by 47%. Cell impedance and lactate dehydrogenase measurements indicated a cytostatic but not a cytotoxic mechanism. Flow cytometry and 5-ethynyl-2′-deoxyuridine incorporation revealed a decreased number of cells in S phase and suggested cell cycle arrest in G0 or G2 phase. Both the antiproliferative and antiviral effects of artesunate at 10 μM were reversible. Thus, artesunate inhibits BKV replication in RPTECs in a concentration-dependent manner by inhibiting BKV gene expression and genome replication. The antiviral mechanism appears to be closely connected to cytostatic effects on the host cell, underscoring the dependence of BKV on host cell proliferative functions. PMID:24145549

Long-term treatment with green tea polyphenols modifies the gut microbiome of female sprague-dawley rats.

PubMed

Wang, Jincheng; Tang, Lili; Zhou, Hongyuan; Zhou, Jun; Glenn, Travis C; Shen, Chwan-Li; Wang, Jia-Sheng

2018-06-01

Green tea polyphenols (GTP) have been shown to exert a spectrum of health benefits to animals and humans. It is plausible that the beneficial effects of GTP are a result of its interaction with the gut microbiota. This study evaluated the effect of long-term treatment with GTP on the gut microbiota of experimental rats and the potential linkage between changes of the gut microbiota with the beneficial effects of GTP. Six-month-old Sprague-Dawley rats were randomly allocated into three dosing regimens (0, 0.5%, and 1.5% of GTP) and followed for 6 months. At the end of month 3 or month 6, half of the animals from each group were sacrificed and their colon contents were collected for microbiome analysis using 16S ribosomal RNA and shotgun metagenomic community sequencing. GTP treatment significantly decreased the biodiversity and modified the microbial community in a dose-dependent manner; similar patterns were observed at both sampling times. Multiple operational taxonomic units and phylotypes were modified: the phylotypes Bacteroidetes and Oscillospira, previously linked to the lean phenotype in human and animal studies, were enriched; and Peptostreptococcaceae previously linked to colorectal cancer phenotype was depleted in GTP treated groups in a dose-dependent manner. Several microbial gene orthologs were modified, among which genes related to energy production and conversion were consistently enriched in samples from month 6 in a dose-dependent manner. This study showed that long-term treatment with GTP induced a dose-dependent modification of the gut microbiome in experimental rats, which might be linked to beneficial effects of GTP. Copyright © 2018 Elsevier Inc. All rights reserved.

Hydrostatic Compress Force Enhances the Viability and Decreases the Apoptosis of Condylar Chondrocytes through Integrin-FAK-ERK/PI3K Pathway.

PubMed

Ma, Dandan; Kou, Xiaoxing; Jin, Jing; Xu, Taotao; Wu, Mengjie; Deng, Liquan; Fu, Lusi; Liu, Yi; Wu, Gang; Lu, Haiping

2016-11-07

Reduced mechanical stimuli in many pathological cases, such as hemimastication and limited masticatory movements, can significantly affect the metabolic activity of mandibular condylar chondrocytes and the growth of mandibles. However, the molecular mechanisms for these phenomena remain unclear. In this study, we hypothesized that integrin-focal adhesion kinase (FAK)-ERK (extracellular signal-regulated kinase)/PI3K (phosphatidylinositol-3-kinase) signaling pathway mediated the cellular response of condylar chondrocytes to mechanical loading. Primary condylar chondrocytes were exposed to hydrostatic compressive forces (HCFs) of different magnitudes (0, 50, 100, 150, 200, and 250 kPa) for 2 h. We measured the viability, morphology, and apoptosis of the chondrocytes with different treatments as well as the gene, protein expression, and phosphorylation of mechanosensitivity-related molecules, such as integrin α2, integrin α5, integrin β1, FAK, ERK, and PI3K. HCFs could significantly increase the viability and surface area of condylar chondrocytes and decrease their apoptosis in a dose-dependent manner. HCF of 250 kPa resulted in a 1.51 ± 0.02-fold increase of cell viability and reduced the ratio of apoptotic cells from 18.10% ± 0.56% to 7.30% ± 1.43%. HCFs could significantly enhance the mRNA and protein expression of integrin α2, integrin α5, and integrin β1 in a dose-dependent manner, but not ERK1, ERK2, or PI3K. Instead, HCF could significantly increase phosphorylation levels of FAK, ERK1/2, and PI3K in a dose-dependent manner. Cilengitide, the potent integrin inhibitor, could dose-dependently block such effects of HCFs. HCFs enhances the viability and decreases the apoptosis of condylar chondrocytes through the integrin-FAK-ERK/PI3K pathway.

Hydrostatic Compress Force Enhances the Viability and Decreases the Apoptosis of Condylar Chondrocytes through Integrin-FAK-ERK/PI3K Pathway

PubMed Central

Ma, Dandan; Kou, Xiaoxing; Jin, Jing; Xu, Taotao; Wu, Mengjie; Deng, Liquan; Fu, Lusi; Liu, Yi; Wu, Gang; Lu, Haiping

2016-01-01

Reduced mechanical stimuli in many pathological cases, such as hemimastication and limited masticatory movements, can significantly affect the metabolic activity of mandibular condylar chondrocytes and the growth of mandibles. However, the molecular mechanisms for these phenomena remain unclear. In this study, we hypothesized that integrin-focal adhesion kinase (FAK)-ERK (extracellular signal–regulated kinase)/PI3K (phosphatidylinositol-3-kinase) signaling pathway mediated the cellular response of condylar chondrocytes to mechanical loading. Primary condylar chondrocytes were exposed to hydrostatic compressive forces (HCFs) of different magnitudes (0, 50, 100, 150, 200, and 250 kPa) for 2 h. We measured the viability, morphology, and apoptosis of the chondrocytes with different treatments as well as the gene, protein expression, and phosphorylation of mechanosensitivity-related molecules, such as integrin α2, integrin α5, integrin β1, FAK, ERK, and PI3K. HCFs could significantly increase the viability and surface area of condylar chondrocytes and decrease their apoptosis in a dose-dependent manner. HCF of 250 kPa resulted in a 1.51 ± 0.02-fold increase of cell viability and reduced the ratio of apoptotic cells from 18.10% ± 0.56% to 7.30% ± 1.43%. HCFs could significantly enhance the mRNA and protein expression of integrin α2, integrin α5, and integrin β1 in a dose-dependent manner, but not ERK1, ERK2, or PI3K. Instead, HCF could significantly increase phosphorylation levels of FAK, ERK1/2, and PI3K in a dose-dependent manner. Cilengitide, the potent integrin inhibitor, could dose-dependently block such effects of HCFs. HCFs enhances the viability and decreases the apoptosis of condylar chondrocytes through the integrin-FAK-ERK/PI3K pathway. PMID:27827993

Harman induces CYP1A1 enzyme through an aryl hydrocarbon receptor mechanism

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

El Gendy, Mohamed A.M.; El-Kadi, Ayman O.S., E-mail: aelkadi@pharmacy.ualberta.c

Harman is a common compound in several foods, plants and beverages. Numerous studies have demonstrated its mutagenic, co-mutagenic and carcinogenic effects; however, the exact mechanism has not been fully identified. Aryl hydrocarbon receptor (AhR) is a transcription factor regulating the expression of the carcinogen-activating enzyme; cytochrome P450 1A1 (CYP1A1). In the present study, we examined the ability of harman to induce AhR-mediated signal transduction in human and rat hepatoma cells; HepG2 and H4IIE cells. Our results showed that harman significantly induced CYP1A1 mRNA in a time- and concentration-dependent manner. Similarly, harman significantly induced CYP1A1 at protein and activity levels inmore » a concentration-dependent manner. Moreover, the AhR antagonist, resveratrol, inhibited the increase in CYP1A1 activity by harman. The RNA polymerase inhibitor, actinomycin D, completely abolished the CYP1A1 mRNA induction by harman, indicating a transcriptional activation. The role of AhR in CYP1A1 induction by harman was confirmed by using siRNA specific for human AhR. The ability of harman to induce CYP1A1 was strongly correlated with its ability to stimulate AhR-dependent luciferase activity and electrophoretic mobility shift assay. At post-transcriptional and post-translational levels, harman did not affect the stability of CYP1A1 at the mRNA and the protein levels, excluding other mechanisms participating in the obtained effects. We concluded that harman can directly induce CYP1A1 gene expression in an AhR-dependent manner and may represent a novel mechanism by which harman promotes mutagenicity, co-mutagenicity and carcinogenicity.« less

Aluminium oxide nanoparticles induced morphological changes, cytotoxicity and oxidative stress in Chinook salmon (CHSE-214) cells.

PubMed

Srikanth, Koigoora; Mahajan, Amit; Pereira, Eduarda; Duarte, Armando Costa; Venkateswara Rao, Janapala

2015-10-01

Aluminium oxide nanoparticles (Al2 O3 NPs) are increasingly used in diverse applications that has raised concern about their safety. Recent studies suggested that Al2 O3 NPs induced oxidative stress may be the cause of toxicity in algae, Ceriodaphnia dubia, Caenorhabditis elegans and Danio rerio. However, there is paucity on the toxicity of Al2 O3 NPs on fish cell lines. The current study was aimed to investigate Al2 O3 NPs induced cytotoxicity, oxidative stress and morphological abnormality of Chinnok salmon cells (CHSE-214). A dose-dependent decline in cell viability was observed in CHSE-214 cells exposed to Al2 O3 NPs. Oxidative stress induced by Al2 O3 NPs in CHSE-214 cells has resulted in the significant reduction of superoxide dismutase, catalase and glutathione in a dose-dependent manner. However, a significant increase in glutathione sulfo-transferase and lipid peroxidation was observed in CHSE-214 cells exposed to Al2 O3 NPs in a dose-dependent manner. Significant morphological changes in CHSE-214 cells were observed when exposed to Al2 O3 NPs at 6, 12 and 24 h. The cells started to detach and appear spherical at 6 h followed by loss of cellular contents resulting in the shrinking of the cells. At 24 h, the cells started to disintegrate and resulted in cell death. Our data demonstrate that Al2 O3 NPs induce cytotoxicity and oxidative stress in a dose-dependent manner in CHSE-214 cells. Thus, our current work may serve as a base-line study for future evaluation of toxicity studies using CHSE-214 cells. Copyright © 2015 John Wiley & Sons, Ltd.

Anti-inflammatory and PPAR transactivational properties of flavonoids from the roots of Sophora flavescens.

PubMed

Quang, Tran Hong; Ngan, Nguyen Thi Thanh; Minh, Chau Van; Kiem, Phan Van; Tai, Bui Huu; Nhiem, Nguyen Xuan; Thao, Nguyen Phuong; Luyen, Bui Thi Thuy; Yang, Seo Young; Kim, Young Ho

2013-09-01

Anti-inflammatory and peroxisome proliferator-activated receptors (PPARs) transactivational effects of nine compounds (1 - 9) from the roots of Sophora flavescens were evaluated using NF-κB-luciferase, reverse transcriptase polymerase chain reaction, peroxisome proliferator response element (PPRE)-luciferase, and GAL-4-PPAR chimera assays. Compounds 4 and 8 significantly inhibited TNFα-induced NF-κB transcriptional activity in HepG2 cells in a dose-dependent manner, with IC₅₀ values of 4.0 and 4.4 μM, respectively. Furthermore, the transcriptional inhibitory function of these compounds was confirmed by a decrease in cyclooxgenase 2 and inducible nitric oxide synthase gene expression levels in HepG2 cells. Compounds 1, 3, 5, 6, 8, and 9 significantly activated the transcription of PPARs in a dose-dependent manner, with EC₅₀ values ranging from 1.1 to 13.0 μM. Compounds 1, 3, 5, 6, 8, and 9 exhibited dose-dependent PPARα transactivational activity, with EC₅₀ values in a range of 0.9 - 16.0 μM. Compounds 1, 3, 8, and 9 also significantly upregulated PPARγ activity in a dose-dependent manner, with EC₅₀ values of 10.5, 6.6, 15.7, and 1.6 μM, whereas compounds 1, 8, and 9 demonstrated transactivational PPARβ(δ) effects with EC₅₀ values of 11.4, 10.3, and 1.5 μM, respectively. These results provide a scientific rationale for the use of the roots of S. flavescens and warrant further studies to develop new agents for the prevention and treatment of inflammatory and metabolic diseases. Copyright © 2012 John Wiley & Sons, Ltd.

Strings on a Violin: Location Dependence of Frequency Tuning in Active Dendrites.

PubMed

Das, Anindita; Rathour, Rahul K; Narayanan, Rishikesh

2017-01-01

Strings on a violin are tuned to generate distinct sound frequencies in a manner that is firmly dependent on finger location along the fingerboard. Sound frequencies emerging from different violins could be very different based on their architecture, the nature of strings and their tuning. Analogously, active neuronal dendrites, dendrites endowed with active channel conductances, are tuned to distinct input frequencies in a manner that is dependent on the dendritic location of the synaptic inputs. Further, disparate channel expression profiles and differences in morphological characteristics could result in dendrites on different neurons of the same subtype tuned to distinct frequency ranges. Alternately, similar location-dependence along dendritic structures could be achieved through disparate combinations of channel profiles and morphological characteristics, leading to degeneracy in active dendritic spectral tuning. Akin to strings on a violin being tuned to different frequencies than those on a viola or a cello, different neuronal subtypes exhibit distinct channel profiles and disparate morphological characteristics endowing each neuronal subtype with unique location-dependent frequency selectivity. Finally, similar to the tunability of musical instruments to elicit distinct location-dependent sounds, neuronal frequency selectivity and its location-dependence are tunable through activity-dependent plasticity of ion channels and morphology. In this morceau, we explore the origins of neuronal frequency selectivity, and survey the literature on the mechanisms behind the emergence of location-dependence in distinct forms of frequency tuning. As a coda to this composition, we present some future directions for this exciting convergence of biophysical mechanisms that endow a neuron with frequency multiplexing capabilities.

Angiotensin II stimulates calcium-dependent activation of c-Jun N-terminal kinase.

PubMed Central

Zohn, I E; Yu, H; Li, X; Cox, A D; Earp, H S

1995-01-01

In GN4 rat liver epithelial cells, angiotensin II (Ang II) and other agonists which activate phospholipase C stimulate tyrosine kinase activity in a calcium-dependent, protein kinase C (PKC)-independent manner. Since Ang II also produces a proliferative response in these cells, we investigated downstream signaling elements traditionally linked to growth control by tyrosine kinases. First, Ang II, like epidermal growth factor (EGF), stimulated AP-1 binding activity in a PKC-independent manner. Because increases in AP-1 can reflect induction of c-Jun and c-Fos, we examined the activity of the mitogen-activated protein (MAP) kinase family members Erk-1 and -2 and the c-Jun N-terminal kinase (JNK), which are known to influence c-Jun and c-Fos transcription. Ang II stimulated MAP kinase (MAPK) activity but only approximately 50% as effectively as EGF; again, these effects were independent of PKC. Ang II also produced a 50- to 200-fold activation of JNK in a PKC-independent manner. Unlike its smaller effect on MAPK, Ang II was approximately four- to sixfold more potent in activating JNK than EGF was. Although others had reported a lack of calcium ionophore-stimulated JNK activity in lymphocytes and several other cell lines, we examined the role of calcium in GN4 cells. The following results suggest that JNK activation in rat liver epithelial cells is at least partially Ca(2+) dependent: (i) norepinephrine and vasopressin hormones that increase inositol 1,4,5-triphosphate stimulated JNK; (ii) both thapsigargin, a compound that produces an intracellular Ca(2+) signal, and Ca(2+) ionophores stimulated a dramatic increase in JNK activity (up to 200-fold); (iii) extracellular Ca(2+) chelation with ethylene glycol tetraacetic acid (EGTA) inhibited JNK activation by ionophore and intracellular chelation with 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl-ester (BAPTA-AM) partially inhibited JNK activation by Ang II or thapsigargin; and (iv) JNK activation by Ang II was inhibited by pretreatment of cells with thapsigargin and EGTA, a procedure which depletes intracellular Ca(2+) stores. JNK activation following Ang II stimulation did not involve calmodulin; either W-7 nor calmidizolium, in concentrations sufficient to inhibit Ca(2+)/calmodulin-dependent kinase II, blocked JNK activation by Ang II. In contrast, genistein, in concentrations sufficient to inhibit Ca(2+)-dependent tyrosine phosphorylation, prevented Ang II and thapsigargin-induced JNK activation. In summary, in GN4 rat liver epithelial cells, Ang II stimulates JNK via a novel Ca(2+)-dependent pathway. The inhibition by genistein suggest that Ca(2+)-dependent tyrosine phosphorylation may modulate the JNK pathway in a cell type-specific manner, particularly in cells with a readily detectable Ca(2+)-regulated tyrosine kinase. PMID:7565768

Liquid level, void fraction, and superheated steam sensor for nuclear reactor cores

DOEpatents

Tokarz, Richard D.

1983-01-01

An apparatus for detecting nominal phase conditions of coolant in a reactor vessel comprising one or more lengths of tubing each leading from a location being monitored to a closed outer end exterior of the vessel. Temperature is sensed at the open end of each length of tubing. Pressure within the tubing is also sensed. Both measurements are directed to an analyzer which compares the measured temperature to the known saturated temperature of the coolant at the measured pressure. In this manner, the nominal phase conditions of the coolant are constantly monitored.

Temperature distribution of a hot water storage tank in a simulated solar heating and cooling system

NASA Technical Reports Server (NTRS)

Namkoong, D.

1976-01-01

A 2,300-liter hot water storage tank was studied under conditions simulating a solar heating and cooling system. The initial condition of the tank, ranging from 37 C at the bottom to 94 C at the top, represented a condition midway through the start-up period of the system. During the five-day test period, the water in the tank gradually rose in temperature but in a manner that diminished its temperature stratification. Stratification was found not to be an important factor in the operation of the particular solar system studied.

Temperature changes induced by 809-nm GaAlAs laser at the implant-bone interface during simulated surface decontamination.

PubMed

Kreisler, Matthias; Al Haj, Haitham; D'Hoedt, Bernd

2003-02-01

The aim of the study was to investigate temperature changes at the implant-bone interface during simulated implant surface decontamination with a 809-nm gallium-aluminium-arsenid (GaAlAs) semiconductor laser. Stepped cylinder implants with a diameter of 3.8 mm and a length of 11 mm with two different surfaces (sand-blasted and acid etched, and hydroxyapatite-coated) were inserted into bone blocks cut from freshly resected pig femurs. Access holes of 0.5 mm were drilled into the bone, to allow K-type thermocouples to contact periimplant bone in different parts of the cavity. An artificial periimplant bone defect provided access for laser irradiation in the coronal third. A 600-micrometer optic fiber was used at a distance of 0.5 mm from the implant surface. Power output varied between 0.5 and 2.5 W in the continuous wave mode. The bone block was placed into a 37 degrees C water bath in order to simulate in vivo thermal conductivity and diffusitivity of heat. Temperature elevations during irradiation were registered for a period of 120 s. In mean, the critical threshold of 47 degrees C was exceeded after 9.0 s at 2.5 W, 12.5 s at 2.0 W, 18.0 s at 1.5 W and 30.5 s at 1.0 W. Surface characteristics did not have a significant effect on temperature elevations. In an energy-dependent manner, implant surface decontamination with an 809-nm GaAlAs laser must be limited in time to allow the implant and bone to cool down. Clinical guidelines are presented to avoid tissue damage.