Growth mechanism changes in pseudo-dewetted monolayer poly(ethylene oxide) crystallization
NASA Astrophysics Data System (ADS)
Zhu, Dun-Shen; Chen, Er-Qiang; Shi, An-Chang; Cheng, Stephen
2006-03-01
Crystal growth mechanism changes have been observed in pseudo-dewetted monolayers of low molecular weight (LMW) (PEO) on freshly cleaved hydrophilic mica surfaces [HPEO(4250) which have -OH groups at both ends and MHPEO(4700) which has one -OH and one -OCH3 as end groups]. X-ray scattering reflectivity measurements show a wetted monolayer of molten PEO with a thickness of ˜ 4.5 nm on the mica surface. Non-adsorbed PEO droplets sit on top of the wetted monolayer. A two-step process for PEO single crystal growth under isothermal conditions was identified utilizing in-situ atomic force microscopy at different crystallization temperatures (Tx). In the first step, the crystal grows within the droplet which supplies the molten PEO that participates in the crystal formation. In this second-step, the wetted monolayer at the growth front is depleted by about 1.5 - 2.5 nm. The growing crystal lateral sizes obey a power law of t^α (t: time). At a high Tx of 63 C for MHPEO(4700), the growth behavior obeys r t (α = 1). While in the case of HPEO(4250), its growth behavior follows r t^0.5 (α = 0.5) in the whole Tx range. With decreasing Tx, the growth of MHPEO(4700) falls into a scaling law of r t^α (0.5 < α < 1).
NASA Astrophysics Data System (ADS)
Stemshorn, Andrew K.; Vohra, Yogesh K.; Smith, Spencer J.
2018-06-01
Changes in bulk crystallization behavior following devitrification at high pressure are investigated for a Fe78B13Si9 composition metallic glass using in-situ energy dispersive x-ray powder diffraction. Crystallization with time was evaluated for a series of measurements to a maximum pressure of 5.63 ± 0.15 GPa for the Fe78B13Si9 glass. Pressure was found to strongly affect onset bulk crystallization temperature Tx. Crystallization at each pressure was found to progress in two stages. In the first stage, α-Fe precipitates and in the second Fe2B forms while α-Fe continues to crystallize. Complementary high pressure room temperature studies were conducted.
Shrinking water's no man's land by lifting its low-temperature boundary
NASA Astrophysics Data System (ADS)
Seidl, Markus; Fayter, Alice; Stern, Josef N.; Zifferer, Gerhard; Loerting, Thomas
2015-04-01
Investigation of the properties and phase behavior of noncrystalline water is hampered by rapid crystallization in the so-called "no man's land." We here show that it is possible to shrink the no man's land by lifting its low-temperature boundary, i.e., the pressure-dependent crystallization temperature Tx(p ) . In particular, we investigate two types of high-density amorphous ice (HDA) in the pressure range of 0.10 -0.50 GPa and show that the commonly studied unannealed state, uHDA, is up to 11 K less stable against crystallization than a pressure-annealed state called eHDA. We interpret this finding based on our previously established microscopic picture of uHDA and eHDA, respectively [M. Seidl et al., Phys. Rev. B 88, 174105 (2013), 10.1103/PhysRevB.88.174105]. In this picture the glassy uHDA matrix contains ice Ih-like nanocrystals, which simply grow upon heating uHDA at pressures ≤0.20 GPa . By contrast, they experience a polymorphic phase transition followed by subsequent crystal growth at higher pressures. In comparison, upon heating purely glassy eHDA, ice nuclei of a critical size have to form in the first step of crystallization, resulting in a lifted Tx(p ) . Accordingly, utilizing eHDA enables the study of amorphous ice at significantly higher temperatures at which we regard it to be in the ultraviscous liquid state. This will boost experiments aiming at investigating the proposed liquid-liquid phase transition.
Temperature Effects in the ATIC BGO Calorimeter
NASA Technical Reports Server (NTRS)
Isbert, J.; Adams, J. H.; Ahn, H.; Bashindzhagyan, G.; Batkov, K.; Chang, J.; Christl, M. J.; Fazely, A.; Ganel, O.; Gunasigha, R.
2006-01-01
The Advanced Thin Ionization Calorimeter (ATIC) Balloon Experiment contains a segmented calorimeter composed of 320 individual BGO crystals (18 radiation lengths deep) to determine the particle energy. Like all inorganic scintillation crystals the light output of BGO depends not only on the energy deposited by particles but also on the temperature of the crystal. ATIC had successful flights in 2000/2001 and 2002/2003 from McMurdo, Antarctica. The temperature of balloon instruments varies during their flights at altitude due to sun angle variations and differences in albedo from the ground and is monitored and recorded. In order to determine the temperature sensitivity of the ATIC calorimeter it was temperature cycled in the thermal vacuum chamber at the CSBF in Palestine, TX. The temperature dependence is derived from the pulse height response to cosmic ray muons at various temperatures.
Crystallization Behavior of A Bulk Amorphous Mg62Cu26Y12 Alloy
NASA Astrophysics Data System (ADS)
Wu, Shyue-Sheng; Chin, Tsung-Shune; Su, Kuo-Chang
1994-07-01
The crystallization temperature, the associated activation energy and the crystallized structure of a bulk amorphous Mg62Cu26Y12 alloy with a diameter of 2.5 mm were studied. It possesses a one-step crystallization behavior. The crystallization reaction was found to be represented by: AM(MG62Cu26Y12)→Mg2Cu+MgY+CuY+Mg, ( Tx=188°C, Eac=134 kJ/mol) where AM represents the amorphous state, T x the crystallization temperature at an infinitesimal heating rate, and E ac the associated activation energy. The amount of crystalline phases were found to be Mg2Cu:MgY:CuY=76:17:7. The Mg phase is identifiable only by high resolution electron microscopy, not by X-ray diffraction. The crystallization leads to a sharp rise in electrical resistivity which is reversed to those of iron-based amorphous alloys.
NASA Astrophysics Data System (ADS)
Souri, Dariush
2015-01-01
Ternary tellurate glasses of the form xSb-(60-x)V2O5-40TeO2 (0≤x≤15 in mol%) were prepared by using the usual melt quenching method. Differential scanning calorimetry (DSC) at different heating rates (φ) was used to thermal analyze and to gain more insight in to the thermal stability, glass forming tendency and so calorimetric behavior of the present glasses. The glass transition temperature (Tg), the temperature corresponding to the onset of crystallization (Tx) and also the crystallization temperature (TCr) were obtained at different heating rates, to estimate the key kinetic parameter of activation energy of crystallization (ΔE) by using different empirical formulas. Also some other thermal parameters such as thermal stability and glass forming tendency were determined. It was found that Tg, Tx and TCr increase with increase in Sb content and also with increase in heating rate. Moreover, Makishima-Makenzie's theory was employed to evaluate the Poisson's ratio and elastic moduli, indicating a strong relation between elastic properties and the structure of glass. From the mechanical and thermal data and also the values of oxygen molar volume (
NASA Astrophysics Data System (ADS)
Singh, Ashish Kumar
Fe-based amorphous alloys are gaining increasing attention due to their exceptional wear and corrosion resistance for potential structural applications. Two major challenges that are hindering the commercialization of these amorphous alloys are difficulty in processing of bulk shapes (diameter > 10 mm) and lack of ductility. Spark plasma sintering (SPS) is evolving as a promising technique for processing bulk shapes of amorphous and nanocrystalline materials. The objective of this work is to investigate densification behavior, nanocrystallization, and mechanical properties of SPS sintered Fe-based amorphous alloys of composition Fe48Cr15Mo14Y2C15B6. SPS processing was performed in three distinct temperature ranges of amorphous alloys: (a) below glass transition temperature (Tg), (b) between Tg and crystallization temperature (Tx), and (c) above Tx. Punch displacement data obtained during SPS sintering was correlated with the SPS processing parameters such as temperature, pressure, and sintering time. Powder rearrangement, plastic deformation below T g, and viscous flow of the material between Tg and Tx were observed as the main densification stages during SPS sintering. Micro-scale temperature distributions at the point of contact and macro-scale temperature distribution throughout the sample during SPS of amorphous alloys were modeled. The bulk amorphous alloys are expected to undergo structural relaxation and nanocrystallization during SPS sintering. X-ray diffraction (XRD), small angle neutron scattering (SANS), and transmission electron microscopy (TEM) was performed to investigate the evolution of nanocrystallites in SPS sintered Fe-based bulk amorphous alloys. The SANS analysis showed significant scattering for the samples sintered in the supercooled region indicating local structural and compositional changes with the profuse nucleation of nano-clusters (~4 nm). Compression tests and microhardness were performed on the samples sintered at different temperatures ranging from 570 °C to 800 °C. Maximum compression strength (1.1+/-0.2 MPa) was obtained for the samples sintered in the supercooled region. Effects of crystallization on tribological behavior of sintered samples were also investigated where crystallization resulted in increase in wear resistance. Laser surface hardening of SPS sintered amorphous samples were performed. Depending on the processing parameters, the laser surface irradiation causes structural relaxation and nanocrystallization, resulting in surface hardening.
NASA Astrophysics Data System (ADS)
Nishiuchi, Kenichi; Yamada, Noboru; Kawahara, Katsumi; Kojima, Rie
2007-11-01
Reduction of the film thickness of phase-change film and the adoption of GeN- or ZrO2-based dielectric films are both effective in achieving good thermal stability in phase-change optical disks. It was experimentally confirmed that, at a heating rate of 10 °C/min, the crystallization temperature Tx of the Ge2Sb2Te5 amorphous film when sandwiched by ZnS-SiO2 films markedly increases from 162 to 197 °C, while the thickness of the Ge2Sb2Te5 film decreases from 10 to 3 nm. Tx also slightly increases when ZnS-SiO2 films are substituted for GeN-based films (from 162 to 165 °C) and ZrO2-based films (from 162 to 167 °C). At the same time, the activation energy of crystallization is 2.4 eV for both GeN- and ZrO2-based films, and is higher than 2.2 eV for ZnS-SiO2 films.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Corrêa, L. C.; Marchi-Salvador, D. P.; Cintra, A. C. O.
2006-08-01
A myotoxic Asp49-PLA{sub 2} with low catalytic activity from B. jararacussu (BthTX-II) was crystallized in the monoclinic crystal system; a complete X-ray diffraction data set was collected and a molecular-replacement solution was obtained. The oligomeric structure of BthTX-II resembles those of the Asp49-PLA{sub 2} PrTX-III and all bothropic Lys49-PLA{sub 2}s. For the first time, a complete X-ray diffraction data set has been collected from a myotoxic Asp49-phospholipase A{sub 2} (Asp49-PLA{sub 2}) with low catalytic activity (BthTX-II from Bothrops jararacussu venom) and a molecular-replacement solution has been obtained with a dimer in the asymmetric unit. The quaternary structure of BthTX-II resemblesmore » the myotoxin Asp49-PLA{sub 2} PrTX-III (piratoxin III from B. pirajai venom) and all non-catalytic and myotoxic dimeric Lys49-PLA{sub 2}s. In contrast, the oligomeric structure of BthTX-II is different from the highly catalytic and non-myotoxic BthA-I (acidic PLA{sub 2} from B. jararacussu). Thus, comparison between these structures should add insight into the catalytic and myotoxic activities of bothropic PLA{sub 2}s.« less
Ferromagnetism in UCo1-xMnxAl and UCo1-xVxAl
NASA Astrophysics Data System (ADS)
Izmaylov, M.; Rafaja, D.; Sechovský, V.; Andreev, A. V.
2002-01-01
UCoAl is an itinerant 5 f-electron metamagnet with a tiny critical field of transition B c≈0.4 T (at 1.3 K). Critical magnetic parameters of this material are strongly sensitive to chemical environment of U atoms. We present results of a pilot study of formation, crystal structure and magnetism of UCo1-xTxAl compounds for T=Mn and V, x≤0.1. All these compounds have been found to be isostructural with the parent compound. Already for x=0.01 in both systems a spontaneous magnetization M s has been observed at low temperatures. Anomalies in the AC susceptibility as a function of temperature point to T c≈28 and 25 K respectively for Mn and V doping. The ferromagnetism induced in UCo1-xTxAl compounds due to a substitution of light transition metal for Co is discussed within a model considering effects of varying 5 f-ligand hybridization on the stability of U 5 f-moment and on exchange interactions.
Tang, Dianping; Zhang, Bing; Tang, Juan; Hou, Li; Chen, Guonan
2013-07-16
A novel displacement-type quartz crystal microbalance (QCM) immunosensing strategy, based on glucose and its analogue dextran for concanavalin A (ConA) binding sites, was designed for ultrasensitive monitoring of small molecular biotoxins (brevetoxin B, PbTx-2, used as a model) with signal amplification on a graphene-functionalized sensing interface. To construct such a QCM immunosensing platform, phenoxy-functionalized dextran (DexP) was initially assembled onto the surface of graphene-coated QCM probe via the π-stacking interaction, and ConA-labeled monoclonal mouse anti-PbTx-2 capture antibody was then immobilized on the DexP-modified probe by dextran-ConA binding. Gold nanoparticle heavily functionalized with glucoamylase and bovine serum albumin-PbTx-2 (PbTx-2-BSA) conjugate was employed as the trace tag. A competitive-type immunoassay format was adopted for the online monitoring of PbTx-2 between anti-PbTx-2 antibody immobilized on the QCM probe and PbTx-2-BSA labeled on the gold nanoparticle. Accompanying the gold nanoparticle, the carried glucoamylase could hydrolyze amylopectin in glucose. The produced glucose competed with dextran for ConA and displaced the ConA-streptavidin-anti-PbTx-2 complex from the QCM probe, resulting in the frequency change. Under optimal conditions, the frequency of the QCM immunosensor was indirectly proportional to the concentration of target PbTx-2 in the sample and exhibited a dynamic range from 1.0 pg·mL(-1) to 10 ng·mL(-1) with a detection limit (LOD) of 0.6 pg·mL(-1) at the 3Sblank level. Intra- and interassay coefficients of variation were below 7.5% and 9.5%, respectively. In addition, the methodology was evaluated for analysis of PbTx-2 in 15 spiked seafood samples and showed good accordance between results obtained by the displacement-type QCM immunosensor and a commercialized enzyme-linked immunosorbent assay (ELISA) method.
Glass Transition Kinetics of 2714A amorphous alloy
NASA Astrophysics Data System (ADS)
Shanker Rao, T.; Lilly Shanker Rao, T.; Shaker, A. M.; Venkataraman, K.
2018-03-01
The present study is related to the kinetics of onset crystallization, Tx and peak crystallization Tp of cobalt based metallic glass 2714A (Co65Si15B14Fe4Ni2) using Differential Scanning Calorimetry (DSC). Non-isothermal measurements were performed at different heating rates (2, 4, 6, 8 and 10 K/min).The experimental results of the crystallization were studied by two most frequently used methods, i.e., Moynihan and Kissinger. The onset crystallization was also studied by VFT and Lasock’s approaches in addition to the above two methods. The activation energy of crystallization Ec was found to be 622.86 and 638.28 kJ/mol and Ex the activation energy of onset crystallization to be 676.34 and 688.93 kJ/mol respectively. Here Tx is used as a substitution of Tg to calculate the fragility index m of the cobalt based metallic glass in the absence of Tg. The fragility index, m which is a measure of glass forming ability (GFA) is also calculated and the value falls between 20 and 60. This indicates the studied metallic glass is an intermediate strong glass.
Magnetic penetration depth and flux dynamics in single-crystal Bi2Sr2CaCu2O8+δ
NASA Astrophysics Data System (ADS)
Harshman, D. R.; Kleiman, R. N.; Inui, M.; Espinosa, G. P.; Mitzi, D. B.; Kapitulnik, A.; Pfiz, T.; Williams, D. Ll.
1991-11-01
The muon-spin-relaxation technique has been used to study vortex dynamics in single-phase superconducting single crystals of Bi2Sr2CaCu2O8+δ (Tc~=90 K). The data indicate motional narrowing of the internal field distribution due to vortex motion (on a time scale comparable to the muon lifetime). A field-dependent lattice transition is also observed at Tx~30 K, as evidenced by the onset of an asymmetric line shape below Tx. Narrowing arising from disordering of the vortices along [001] is also discussed with reference to its effect on the measured penetration depth.
NASA Astrophysics Data System (ADS)
Oueslati, Boutheina; Camberlin, Pierre; Zoungrana, Joël; Roucou, Pascal; Diallo, Saliou
2018-02-01
The relationships between precipitation and temperature in the central Sudano-Sahelian belt are investigated by analyzing 50 years (1959-2008) of observed temperature (Tx and Tn) and rainfall variations. At daily time-scale, both Tx and Tn show a marked decrease as a response to rainfall occurrence, with a strongest departure from normal 1 day after the rainfall event (-0.5 to -2.5 °C depending on the month). The cooling is slightly larger when heavy rainfall events (>5 mm) are considered. The temperature anomalies weaken after the rainfall event, but are still significant several days later. The physical mechanisms accounting for the temperature response to precipitation are analysed. The Tx drop is accounted for by reduced incoming solar radiation associated with increased cloud cover and increased surface evaporation following surface moistening. The effect of evaporation becomes dominant a few days after the rainfall event. The reduced daytime heat storage and the subsequent sensible heat flux result in a later negative Tn anomaly. The effect of rainfall variations on temperature is significant for long-term warming trends. The rainfall decrease experienced between 1959 and 2008 accounts for a rainy season Tx increase of 0.15 to 0.3 °C, out of a total Tx increase of 1.3 to 1.5 °C. These results have strong implications on the assessment of future temperature changes. The dampening or amplifying effects of precipitation are determined by the sign of future precipitation trends. Confidence on temperature changes under global warming partly depend on the robustness of precipitation projections.
Tailoring the Crystal Structure Toward Optimal Super Conductors
2016-06-23
AFRL-AFOSR-VA-TR-2016-0210 TAILORING THE CRYSTAL STRUCTURE TOWARD OPTIMAL SUPERCONDUCTORS Emilia Morosan WILLIAM MARSH RICE UNIV HOUSTON TX Final...TAILORING THE CRYSTAL STRUCTURE TOWARD OPTIMAL SUPERCONDUCTORS 5a. CONTRACT NUMBER FA9550-11-1-0023 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...studied the properties of layered transition metal compounds in search of unconventional superconductors . The aim is to identify ground states competing
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gopolan,G.; Thwin, M.; Gopalakrishnakone, P.
Russell's viper (Vipera russelli, also known as Daboia russelli) is one of the major causes of fatal snakebites. To date, five Daboia russelli subspecies have been recognized. Daboiatoxin (DbTx) is the main lethal phospholipase A{sub 2} (PLA{sub 2}) toxin in the venom of D. russelli siamensis (Myanmar viper) and has strong neurotoxic, myotoxic and cytotoxic activities. DbTx and its homologous neurotoxins viperotoxin F from D. russelli formosensis (Taiwan viper) and vipoxin from the Bulgarian sand viper V. ammodytes meridionalis consist of complexes between a nontoxic acidic PLA2 protein and an enzymatically active basic PLA2. DbTx and viperotoxin F are presynapticmore » toxins, while vipoxin is postsynaptic. The two chains of DbTx have been separated and their PLA2 enzymatic activity has been measured using the secretory PLA2 assay kit. The enzymatic activity of DbTx chain B is reduced by 30% of its original activity by chain A in a unimolar ratio, thus indicating that DbTx chain A acts as an inhibitor. The lethal activity of the two chains has also been studied in male albino mice and chain A is less lethal than chain B. The crystal structure of DbTx has also been determined and its structural details are compared with those of the two homologues. Furthermore, an attempt is made to correlate the sequence and structural determinants of these toxins with their enzymatic activities and their pharmacological effects.« less
Resilience of rice (Oryza spp.) pollen germination and tube growth to temperature stress.
Coast, Onoriode; Murdoch, Alistair J; Ellis, Richard H; Hay, Fiona R; Jagadish, Krishna S V
2016-01-01
Resilience of rice cropping systems to potential global climate change will partly depend on the temperature tolerance of pollen germination (PG) and tube growth (PTG). Pollen germination of high temperature-susceptible Oryza glaberrima Steud. (cv. CG14) and Oryza sativa L. ssp. indica (cv. IR64) and high temperature-tolerant O. sativa ssp. aus (cv. N22), was assessed on a 5.6-45.4 °C temperature gradient system. Mean maximum PG was 85% at 27 °C with 1488 μm PTG at 25 °C. The hypothesis that in each pollen grain, the minimum temperature requirements (Tn ) and maximum temperature limits (Tx ) for germination operate independently was accepted by comparing multiplicative and subtractive probability models. The maximum temperature limit for PG in 50% of grains (Tx(50) ) was the lowest (29.8 °C) in IR64 compared with CG14 (34.3 °C) and N22 (35.6 °C). Standard deviation (sx ) of Tx was also low in IR64 (2.3 °C) suggesting that the mechanism of IR64's susceptibility to high temperatures may relate to PG. Optimum germination temperatures and thermal times for 1 mm PTG were not linked to tolerating high temperatures at anthesis. However, the parameters Tx(50) and sx in the germination model define new pragmatic criteria for successful and resilient PG, preferable to the more traditional cardinal (maximum and minimum) temperatures. © 2014 John Wiley & Sons Ltd.
Optical and spectroscopic study of erbium doped calcium borotellurite glasses
NASA Astrophysics Data System (ADS)
Gomes, J. F.; Lima, A. M. O.; Sandrini, M.; Medina, A. N.; Steimacher, A.; Pedrochi, F.; Barboza, M. J.
2017-04-01
In this study, 10CaF2 - (29.9-0.4x)CaO - (60-0.6x)B2O3 - xTeO2 - 0,1Er2O3 (x = 10, 16, 22, 30 and 50 mol %) glasses were synthesized, and their optical and spectroscopic properties were investigated. X-ray diffraction, density, glass transition temperature (Tg), crystallization temperature (Tx), refraction index, luminescence, radiative lifetime and optical absorption measurements were carried out. Molar volume (Vm), thermal stability (Tx-Tg), electronic polarizability (αm), optical bang gap energy (Eg) and Judd-Ofelt (JO) parameters Ωt (2,4,6) were also calculated. The results are discussed in terms of tellurium oxide content. The increase of TeO2 in the glasses composition increases density, refractive index and electronic polarizability. The optical band gap energy decreases varying from 3.37 to 2.71 eV for the glasses with 10 and 50 mol% of TeO2, respectively. The optical absorption coefficient spectra show characteristic bands of Er3+ ions. Furthermore, these spectra in NIR region show a decrease of hydroxyl groups as a function of TeO2 addition. Luminescence intensity and radiative lifetimes at 1530 nm show an increasing with the TeO2 content. The JO parameters of Er:CaBTeX glasses follow the trend Ω2 > Ω4 > Ω6 and the quality factor values (Ω4/Ω6) were between 1.37 and 3.07. By comparing the measured lifetime with the calculated radiative decay time, quantum efficiency was calculated. The luminescence emission intensity at 1530 nm decreases with the increase of temperature. The lifetime values show a slight trend to decrease with the temperature increase, from 300 to 420 K, for all the samples.
NASA Astrophysics Data System (ADS)
Bartoš, J.; Zgardzinska, B.; Švajdlenková, H.; Lukešová, M.; Zaleski, R.
2018-05-01
A joint study of the spin probe TEMPO dynamics by ESR and the annihilation rate of ortho-positronium by PALS in four short-and medium-sized n-alkanes is presented. In addition to the usually observed changes in both the reorientation dynamics and size of free volumes at the temperature of melting, Tm, and solid-solid phase transition, Tss, an additional coincidence between the characteristic ESR and PALS temperatures TX1fast ≅ Tb1sol < Tm, Tss was found. The phenomenological analysis of the viscosity data of n-alkanes using the power law equation indicates a presence of locally disordered regions in which the dynamic change occurs at the crossover temperature TX ≅ TX1fast ≅ Tb1sol.
Dynamics anomaly in high-density amorphous ice between 0.7 and 1.1 GPa
NASA Astrophysics Data System (ADS)
Handle, Philip H.; Loerting, Thomas
2016-02-01
We studied high-density amorphous ices between 0.004 and 1.6 GPa by isobaric in situ volumetry and by subsequent ex situ x-ray diffraction and differential scanning calorimetry at 1 bar. Our observations indicate two processes, namely, relaxation in the amorphous matrix and crystallization, taking place at well-separated time scales. For this reason, we are able to report rate constants of crystallization kX and glass-transition temperatures Tg in an unprecedented pressure range. Tg's agree within ±3 K with earlier work in the small pressure range where there is overlap. Both Tg and kX show a pressure anomaly between 0.7 and 1.1 GPa, namely, a kX minimum and a Tg maximum. This anomalous pressure dependence suggests a continuous phase transition from high- (HDA) to very-high-density amorphous ice (VHDA) and faster hydrogen bond dynamics in VHDA. We speculate this phenomenology can be rationalized by invoking the crossing of a Widom line between 0.7 and 1.1 GPa emanating from a low-lying HDA-VHDA critical point. Furthermore, we interpret the volumetric relaxation of the amorphous matrix to be accompanied by viscosity change to explain the findings such that the liquid state can be accessed prior to the crystallization temperature TX at <0.4 GPa and >0.8 GPa.
2002-07-31
Renal stones are never convenient, but they are a particular concern for astronauts who have limited access to treatment during flight. Researchers are examining how earthbound preventions for renal stone formation work in flight, ensuring missions are not ended prematurely due to this medical condition. The micrograph shows calcium oxalate crystals in urine. These small crystals can develop to form renal stones. Principal Investigator: Dr. Peggy Whitson, NASA Johnson Space Center, Houston, TX.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Marchi-Salvador, D. P.; Fernandes, C. A. H.; Amui, S. F.
2006-06-01
A non-catalytic and myotoxic Lys49-PLA{sub 2} from B. jararacussu venom was crystallized with BPB inhibitor and X-ray diffraction data were collected. Preliminary analysis indicates that the ligand is bound to the His48 residue. Structure determination may provide insights into the myotoxic and cytotoxic mechanisms of Lys49-PLA{sub 2}s. For the first time, a non-catalytic and myotoxic Lys49-PLA{sub 2} (BthTX-I from Bothrops jararacussu venom) has been crystallized with BPB inhibitor. X-ray diffraction data were collected and electron-density calculations showed that the ligand is bound to the His48 residue. BthTX-I with His48 chemically modified by BPB shows strongly reduced myotoxic and cytotoxic activities.more » This suggests a biological correlation between the modification of His48, which is associated with catalytic activity of PLA{sub 2}s, and other toxicological activities of Lys49-PLA{sub 2}s.« less
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Li, Helian; Qu, Ronghui; Li, Chao; Guo, Weilin; Han, Xuemei; He, Fang; Ma, Yibing; Xing, Baoshan
2014-07-01
Wheat straw biochars produced at 400, 600 and 800°C (BC400, BC600 and BC800) were used to selectively adsorb PAHs from soil washing effluents. For soil washing effluents contained Phenanthrene (PHE), Fluoranthene (FLU), Pyrene (PYR) and Triton X-100 (TX100), biochars at 2 (for BC800) or 6 g L(-1) (for BC400 and BC600) can remove 71.8-98.6% of PAHs while recover more than 87% of TX100. PAH removals increase with increasing biochar dose. However, excess biochar is detrimental to the recovery of surfactant. For a specific biochar dose, PAH removal and TX100 loss increase with increasing pyrolytic temperature. For BC400 and BC600, PAH removal follows the order of PHE>FLU>PYR, while the order is reversed with PYR>FLU>PHE for BC800. Biochars have much higher sorption affinity for PAHs than for TX100. It is therefore suggested that biochar is a good alternative for selective adsorption of PAHs and recovery of TX100 in soil washing process. Copyright © 2014 Elsevier Ltd. All rights reserved.
The MUSIC of galaxy clusters - II. X-ray global properties and scaling relations
NASA Astrophysics Data System (ADS)
Biffi, V.; Sembolini, F.; De Petris, M.; Valdarnini, R.; Yepes, G.; Gottlöber, S.
2014-03-01
We present the X-ray properties and scaling relations of a large sample of clusters extracted from the Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC) data set. We focus on a sub-sample of 179 clusters at redshift z ˜ 0.11, with 3.2 × 1014 h-1 M⊙ < Mvir < 2 × 1015 h-1 M⊙, complete in mass. We employed the X-ray photon simulator PHOX to obtain synthetic Chandra observations and derive observable-like global properties of the intracluster medium (ICM), as X-ray temperature (TX) and luminosity (LX). TX is found to slightly underestimate the true mass-weighted temperature, although tracing fairly well the cluster total mass. We also study the effects of TX on scaling relations with cluster intrinsic properties: total (M500 and gas Mg,500 mass; integrated Compton parameter (YSZ) of the Sunyaev-Zel'dovich (SZ) thermal effect; YX = Mg,500 TX. We confirm that YX is a very good mass proxy, with a scatter on M500-YX and YSZ-YX lower than 5 per cent. The study of scaling relations among X-ray, intrinsic and SZ properties indicates that simulated MUSIC clusters reasonably resemble the self-similar prediction, especially for correlations involving TX. The observational approach also allows for a more direct comparison with real clusters, from which we find deviations mainly due to the physical description of the ICM, affecting TX and, particularly, LX.
Naima, Z; Siro, T; Juan-Manuel, G D; Chantal, C; René, C; Jerome, D
2001-02-01
The influence of a hydrophilic carrier (PEG 6000) on the polymorphism of carbamazepine, an antiepileptic drug, was investigated in binary physical mixtures and solid dispersions by means of differential scanning calorimetry (DSC), thermal gravimetry, hot-stage microscopy (HSM), and X-ray diffractometry, respectively. This study provides also an attempt to develop a method to calculate more precisely the eutectic composition. In rather ideal physical mixtures, carbamazepine was found as monoclinic Form III. In solid dispersions, the drug was found to crystallize as trigonal Form II; a eutectic invariant in the PEG 6000-rich composition domain (6% of carbamazepine mass) was evidenced by DSC experiments and confirmed by HSM observations. In the binary phase diagram the ideal carbamazepine liquidus curve was located at temperatures higher than the respective experimental ones. This suggests that drug can be maintained in the liquid state in the temperature-mass fraction (T--x) region between the two carbamazepine liquidus curves. This indicates in turn that attractive interactions occur between carbamazepine and PEG 6000-chains. These interactions have been also claimed to prevent carbamazepine from degradation into iminostilbene (a compound resulting from the chemical degradation of carbamazepine which is postulated to be responsible for the idiosyncratic toxicity of the drug) and thought to lead to the crystallization of metastable Carbamazepine II from melt. The negative excess entropy for eutectic mixtures indicated that the drug crystals are finely dispersed in the bulk of polymer chains.
Synthesis and electrochemical performance of Ti3C2Tx with hydrothermal process
NASA Astrophysics Data System (ADS)
Wang, Libo; Zhang, Heng; Wang, Bo; Shen, Changjie; Zhang, Chuanxiang; Hu, Qianku; Zhou, Aiguo; Liu, Baozhong
2016-09-01
In this study, a simple hydrothermal method has been developed to prepare Ti3C2Tx from Ti3AlC2 as a high-performance electrode material for supercapacitors. This method is environmentally friendly and has a low level of danger. The morphology and structure of the Ti3C2Tx can be controlled by hydrothermal reaction time, temperature and NH4F amounts. The prepared Ti3C2Tx was characterized by X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and Brunauer-Emmet-Teller. The results show that the prepared Ti3C2Tx is terminated by O, OH, and F groups. The electrochemical properties of the Ti3C2Tx sample exhibit specific capacitance up to 141 Fcm-3 in 3 M KOH aqueous electrolyte, and even after 1000 cycles, no significant degradation of the volumetric capacitance was observed. These results indicate that the Ti3C2Tx material prepared by this hydrothermal method can be used in high performance supercapacitors.
Experimental Evidence of Low Density Liquid Water under Decompression
NASA Astrophysics Data System (ADS)
Shen, G.; Lin, C.; Sinogeikin, S. V.; Smith, J.
2017-12-01
Water is not only the most important substance for life, but also plays important roles in liquid science for its anomalous properties. It has been widely accepted that water's anomalies are not a result of simple thermal fluctuation, but are connected to the formation of various structural aggregates in the hydrogen bonding network. Among several proposed scenarios, one model of fluctuations between two different liquids has gradually gained traction. These two liquids are referred to as a low-density liquid (LDL) and a high-density liquid (HDL) with a coexistence line in the deeply supercooled regime at elevated pressure. The LDL-HDL transition ends with decreasing pressure at a liquid-liquid critical point (LLCP) with its Widom line extending to low pressures. Above the Widom line lies mostly HDL which is favored by entropy, while LDL, mostly lying below the Widom line, is favored by enthalpy in the tetrahedral hydrogen bonding network. The origin of water's anomalies can then be explained by the increase in structural fluctuations, as water is cooled down to deeply supercooled temperatures approaching the Widom line. Because both the LLCP and the LDL-HDL transition line lie in water's "no man's land" between the homogeneous nucleation temperature (TH, 232 K) and the crystallization temperature (TX, 150 K), the success of experiments exploring this region has been limited thus far. Using a rapid decompression technique integrated with in situ x-ray diffraction, we observe that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140-165K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. The change in crystallization rate with temperature indicates that the LDN is a LDL with its tetrahedrally-coordinated network fully developed and clearly linked to low-density amorphous ices. The observation of the tetrahedral LDL supports the two-liquid model for water including the existence of a LLCP.
NASA Astrophysics Data System (ADS)
Tam, David W.; Song, Yu; Man, Haoran; Cheung, Sky C.; Yin, Zhiping; Lu, Xingye; Wang, Weiyi; Frandsen, Benjamin A.; Liu, Lian; Gong, Zizhou; Ito, Takashi U.; Cai, Yipeng; Wilson, Murray N.; Guo, Shengli; Koshiishi, Keisuke; Tian, Wei; Hitti, Bassam; Ivanov, Alexandre; Zhao, Yang; Lynn, Jeffrey W.; Luke, Graeme M.; Berlijn, Tom; Maier, Thomas A.; Uemura, Yasutomo J.; Dai, Pengcheng
2017-02-01
We use neutron diffraction and muon spin relaxation to study the effect of in-plane uniaxial pressure on the antiferromagnetic (AF) orthorhombic phase in BaFe2As2 and its Co- and Ni-substituted members near optimal superconductivity. In the low-temperature AF ordered state, uniaxial pressure necessary to detwin the orthorhombic crystals also increases the magnetic ordered moment, reaching an 11% increase under 40 MPa for BaFe1.9Co0.1As2 , and a 15% increase for BaFe1.915Ni0.085As2 . We also observe an increase of the AF ordering temperature (TN) of about 0.25 K/MPa in all compounds, consistent with density functional theory calculations that reveal better Fermi surface nesting for itinerant electrons under uniaxial pressure. The doping dependence of the magnetic ordered moment is captured by combining dynamical mean field theory with density functional theory, suggesting that the pressure-induced moment increase near optimal superconductivity is closely related to quantum fluctuations and the nearby electronic nematic phase.
Komaromy-Hiller; von Wandruszka R
1996-01-15
The effects of temperature and Triton X-114 (TX-114) concentration on the fluorescence anisotropy of perylene were investigated before and after detergent clouding. The measured anisotropy values were used to estimate the microviscosity of the micellar interior. In the lower detergent concentration range, an anisotropy maximum was observed at the critical micelle concentration (CMC), while the values decreased in the range immediately above the CMC. This was ascribed to the micellar volume increase, which, in the case of TX-114, was not accompanied by a more ordered internal environment. A gradual decrease of anisotropy and microviscosity with increasing temperature below the cloud point was observed. At the cloud point, no abrupt changes were found to occur. Compared to detergents with more flexible hydrophobic moieties, TX-114 micelles have a relatively ordered micellar interior indicated by the microviscosity and calculated fusion energy values. In the separated micellar phase formed after clouding, the probe anisotropy increased as water was eliminated at higher temperatures.
NASA Astrophysics Data System (ADS)
Mahony, C. R.; Cannon, A. J.
2017-12-01
Climate change can drive local climates outside the range of their historical year-to-year variability, straining the adaptive capacity of ecological and human communities. We demonstrate that interactions between climate variables can produce larger and earlier departures from natural variability than is detectable in individual variables. For example, summer temperature (Tx) and precipitation (Pr) are negatively correlated in most terrestrial regions, such that interannual variability lies along an axis from warm-and-dry to cool-and-wet conditions. A climate change trend perpendicular to this axis, towards warmer-wetter conditions, can depart more quickly from the range of natural variability than a warmer-drier trend. This multivariate "departure intensification" effect is evident in all six CMIP5 models that we examined: 23% (9-34%) of the land area of each model exhibits a pronounced increase in 2σ extremesin the Tx-Pr regime relative to Tx or Pr alone. Observational data suggest that Tx-Pr correlations are sufficient to produce departure intensification in distinct regions on all continents. Departures from the historical Tx-Pr regime may produce ecological disruptions, such as in plant-pathogen interactions and human diseases, that could offset the drought mitigation benefits of increased precipitation. Our study alerts researchers and adaptation practitioners to the presence of multivariate climate change signals and compound extremes that are not detectable in individual climate variables.
Parallel transmission RF pulse design with strict temperature constraints.
Deniz, Cem M; Carluccio, Giuseppe; Collins, Christopher
2017-05-01
RF safety in parallel transmission (pTx) is generally ensured by imposing specific absorption rate (SAR) limits during pTx RF pulse design. There is increasing interest in using temperature to ensure safety in MRI. In this work, we present a local temperature correlation matrix formalism and apply it to impose strict constraints on maximum absolute temperature in pTx RF pulse design for head and hip regions. Electromagnetic field simulations were performed on the head and hip of virtual body models. Temperature correlation matrices were calculated for four different exposure durations ranging between 6 and 24 min using simulated fields and body-specific constants. Parallel transmission RF pulses were designed using either SAR or temperature constraints, and compared with each other and unconstrained RF pulse design in terms of excitation fidelity and safety. The use of temperature correlation matrices resulted in better excitation fidelity compared with the use of SAR in parallel transmission RF pulse design (for the 6 min exposure period, 8.8% versus 21.0% for the head and 28.0% versus 32.2% for the hip region). As RF exposure duration increases (from 6 min to 24 min), the benefit of using temperature correlation matrices on RF pulse design diminishes. However, the safety of the subject is always guaranteed (the maximum temperature was equal to 39°C). This trend was observed in both head and hip regions, where the perfusion rates are very different. Copyright © 2017 John Wiley & Sons, Ltd.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Suzuki, Nobuhiro; Department of Biochemistry, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602; Yamazaki, Yasuo
2008-10-01
The structures of pseudechetoxin and pseudecin suggest that both proteins bind to cyclic nucleotide-gated ion channels in a manner in which the concave surface occludes the pore entrance. Cyclic nucleotide-gated (CNG) ion channels play pivotal roles in sensory transduction by retinal photoreceptors and olfactory neurons. The elapid snake toxins pseudechetoxin (PsTx) and pseudecin (Pdc) are the only known protein blockers of CNG channels. These toxins belong to a cysteine-rich secretory protein (CRISP) family containing an N-terminal pathogenesis-related proteins of group 1 (PR-1) domain and a C-terminal cysteine-rich domain (CRD). PsTx and Pdc are highly homologous proteins, but their blocking affinitiesmore » on CNG channels are different: PsTx blocks both the olfactory and retinal channels with ∼15–30-fold higher affinity than Pdc. To gain further insights into their structure and function, the crystal structures of PsTx, Pdc and Zn{sup 2+}-bound Pdc were determined. The structures revealed that most of the amino-acid-residue differences between PsTx and Pdc are located around the concave surface formed between the PR-1 domain and the CRD, suggesting that the concave surface is functionally important for CNG-channel binding and inhibition. A structural comparison in the presence and absence of Zn{sup 2+} ion demonstrated that the concave surface can open and close owing to movement of the CRD upon Zn{sup 2+} binding. The data suggest that PsTx and Pdc occlude the pore entrance and that the dynamic motion of the concave surface facilitates interaction with the CNG channels.« less
Structural and Functional Analysis of Phytotoxin Toxoflavin-Degrading Enzyme
Kim, Myung-Il; Ma, Jun; Nagamatsu, Tomohisa; Goo, Eunhye; Kim, Hongsup; Hwang, Ingyu; Han, Jaehong; Rhee, Sangkee
2011-01-01
Pathogenic bacteria synthesize and secrete toxic low molecular weight compounds as virulence factors. These microbial toxins play essential roles in the pathogenicity of bacteria in various hosts, and are emerging as targets for antivirulence strategies. Toxoflavin, a phytotoxin produced by Burkholderia glumae BGR1, has been known to be the key factor in rice grain rot and wilt in many field crops. Recently, toxoflavin-degrading enzyme (TxDE) was identified from Paenibacillus polymyxa JH2, thereby providing a possible antivirulence strategy for toxoflavin-mediated plant diseases. Here, we report the crystal structure of TxDE in the substrate-free form and in complex with toxoflavin, along with the results of a functional analysis. The overall structure of TxDE is similar to those of the vicinal oxygen chelate superfamily of metalloenzymes, despite the lack of apparent sequence identity. The active site is located at the end of the hydrophobic channel, 9 Å in length, and contains a Mn(II) ion interacting with one histidine residue, two glutamate residues, and three water molecules in an octahedral coordination. In the complex, toxoflavin binds in the hydrophobic active site, specifically the Mn(II)-coordination shell by replacing a ligating water molecule. A functional analysis indicated that TxDE catalyzes the degradation of toxoflavin in a manner dependent on oxygen, Mn(II), and the reducing agent dithiothreitol. These results provide the structural features of TxDE and the early events in catalysis. PMID:21799856
A pain-inducing centipede toxin targets the heat activation machinery of nociceptor TRPV1
NASA Astrophysics Data System (ADS)
Yang, Shilong; Yang, Fan; Wei, Ningning; Hong, Jing; Li, Bowen; Luo, Lei; Rong, Mingqiang; Yarov-Yarovoy, Vladimir; Zheng, Jie; Wang, Kewei; Lai, Ren
2015-09-01
The capsaicin receptor TRPV1 ion channel is a polymodal nociceptor that responds to heat with exquisite sensitivity through an unknown mechanism. Here we report the identification of a novel toxin, RhTx, from the venom of the Chinese red-headed centipede that potently activates TRPV1 to produce excruciating pain. RhTx is a 27-amino-acid small peptide that forms a compact polarized molecule with very rapid binding kinetics and high affinity for TRPV1. We show that RhTx targets the channel's heat activation machinery to cause powerful heat activation at body temperature. The RhTx-TRPV1 interaction is mediated by the toxin's highly charged C terminus, which associates tightly to the charge-rich outer pore region of the channel where it can directly interact with the pore helix and turret. These findings demonstrate that RhTx binding to the outer pore can induce TRPV1 heat activation, therefore providing crucial new structural information on the heat activation machinery.
Coherent variability between seasonal temperatures and rainfalls in the Iberian Peninsula, 1951-2016
NASA Astrophysics Data System (ADS)
Rodrigo, F. S.
2018-02-01
In this work trends of seasonal mean of daily minimum (TN), maximum (TX), mean (TM) temperatures, daily range of temperature (DTR), and total seasonal rainfall (R) in 35 Iberian stations since mid-twentieth century are studied. The interest is focused on the relationships between temperature variables and rainfall, taking into account the correlation coefficients between R and the temperature variables. The negative link between rainfall and temperatures is detected in the four seasons of the year, except in western stations in winter for TN and TM, and in autumn for TN (for this variable a certain annual cycle is detected, with predominance of positive correlation in winter, negative in spring and summer, and the autumn as transition season). The role of cloud cover is confirmed in those stations with total cloud cover data. Using an average peninsular series, the relationship between nighttime temperature and rainfall related to long wave radiation is confirmed for the four seasons of the year, although in spring and summer has minor importance than in the cold half year. The relationships between R, TN, and TX are in general terms stable after a moving correlation analysis, although the negative correlation between TX and R seems be weakened in spring and autumn and reinforced in summer. The role of convective precipitation in autumn is discussed. The analysis of combined extreme indices in four representative stations shows an increase of warm and dry days, and a decrease of cold and wet days.
2012-01-01
h. Applica- tions occurred when the prevailing wind was blowing perpendicular to the collection site (Fig. 1). Sprays were conducted using a Guardian...min. Permanone 30–30 was mixed 1:2:1 with Crystal Plus 70 T light mineral oil (STE Oil Company, Inc., San Marcos, TX, USA) and ACS grade toluene and...applied at a flow rate of 192 ml/min. Scourge 18+54wasmixed at 1:0.4:0.4with Crystal Plus 70 T light mineral oil and ACS grade toluene and applied at a
Paës, Gabriel; O'Donohue, Michael J
2006-09-18
Enzymatic hydrolysis constitutes an attractive strategy for biorefining of abundant, low-cost agricultural by-products such as wheat bran and straw. However, to adopt such an approach, efficient enzymes are required, in particular xylanases. To promote heat-induced disorganization of the complex cell wall network in wheat bran and thus increase enzymatic hydrolysis, we have attempted to improve the thermoresistance of a GH-11 xylanase that is already moderately thermostable. Using a previously described engineering strategy that involves the introduction of disulphide bridges, a mutant (Tx-xyl-SS3) displaying enhanced thermostability and thermoactivity was obtained. The half life at 70 degrees C (180 min) of Tx-xyl-SS3 is 10-fold greater than that of the wild type enzyme and its specific activity is almost doubled (3500 IU mg(-1)). Despite these improvements, Tx-xyl-SS3 was unsuitable for use at significantly higher reaction temperatures (i.e. 85-95 degrees C) and thus the initial objective of this study remained unaccomplished. However, unexpectedly even at the normal hydrolytic temperature (60 degrees C), Tx-xyl-SS3 was able to solubilize 50% of the wheat bran arabinoxylans, 10 points more than the wild type enzyme in parallel reactions. The data presented here show that this improvement is not directly linked to the increase in thermostability and/or thermoactivity, but rather to other unidentified changes to physico-chemical properties that may allow Tx-xyl-SS3 to better penetrate the cell wall network in wheat bran.
Kim, Hyunsoo; Tanatar, M A; Martin, C; Blomberg, E C; Ni, Ni; Bud'ko, S L; Canfield, P C; Prozorov, R
2018-06-06
Doping evolution of the superconducting gap anisotropy was studied in single crystals of 4d-electron doped Ba(Fe 1-x Rh x ) 2 As 2 using tunnel diode resonator measurements of the temperature variation of the London penetration depth [Formula: see text]. Single crystals with doping levels representative of an underdoped regime x = 0.039 ([Formula: see text] K), close to optimal doping x = 0.057 ([Formula: see text] K) and overdoped x = 0.079 ([Formula: see text] K) and x = 0.131([Formula: see text] K) were studied. Superconducting energy gap anisotropy was characterized by the exponent, n, by fitting the data to the power-law, [Formula: see text]. The exponent n varies non-monotonically with x, increasing to a maximum n = 2.5 for x = 0.079 and rapidly decreasing towards overdoped compositions to 1.6 for x = 0.131. This behavior is qualitatively similar to the doping evolution of the superconducting gap anisotropy in other iron pnictides, including hole-doped (Ba,K)Fe 2 As 2 and 3d-electron-doped Ba(Fe,Co) 2 As 2 superconductors, finding a full gap near optimal doping and strong anisotropy toward the ends of the superconducting dome in the T-x phase diagram. The normalized superfluid density in an optimally Rh-doped sample is almost identical to the temperature-dependence in the optimally doped Ba(Fe,Co) 2 As 2 samples. Our study supports the universal superconducting gap variation with doping and [Formula: see text] pairing at least in iron based superconductors of the BaFe 2 As 2 family.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kim, Hyunsoo; Tanatar, M. A.; Martin, C.
Doping evolution of the superconducting gap anisotropy was studied in single crystals of 4d-electron doped Ba(Fe 1–xRh x) 2As 2 using tunnel diode resonator measurements of the temperature variation of the London penetration depth Δλ( T). Single crystals with doping levels representative of an underdoped regime x = 0.039 ( T c = 15.5 K), close to optimal doping x = 0.057 ( T c = 24.4 K) and overdoped x = 0.079 ( T c = 21.5 K) and x = 0.131( T c = 4.9 K) were studied. Superconducting energy gap anisotropy was characterized by the exponent, n,more » by fitting the data to the power-law, Δλ = AT n. The exponent n varies non-monotonically with x, increasing to a maximum n = 2.5 for x = 0.079 and rapidly decreasing towards overdoped compositions to 1.6 for x = 0.131. This behavior is qualitatively similar to the doping evolution of the superconducting gap anisotropy in other iron pnictides, including hole-doped (Ba,K)Fe 2As 2 and 3d-electron-doped Ba(Fe,Co) 2As 2 superconductors, finding a full gap near optimal doping and strong anisotropy toward the ends of the superconducting dome in the T-x phase diagram. The normalized superfluid density in an optimally Rh-doped sample is almost identical to the temperature-dependence in the optimally doped Ba(Fe,Co) 2As 2 samples. In conclusion, our study supports the universal superconducting gap variation with doping and pairing at least in iron based superconductors of the BaFe 2As 2 family.« less
Kim, Hyunsoo; Tanatar, M. A.; Martin, C.; ...
2018-05-08
Doping evolution of the superconducting gap anisotropy was studied in single crystals of 4d-electron doped Ba(Fe 1–xRh x) 2As 2 using tunnel diode resonator measurements of the temperature variation of the London penetration depth Δλ( T). Single crystals with doping levels representative of an underdoped regime x = 0.039 ( T c = 15.5 K), close to optimal doping x = 0.057 ( T c = 24.4 K) and overdoped x = 0.079 ( T c = 21.5 K) and x = 0.131( T c = 4.9 K) were studied. Superconducting energy gap anisotropy was characterized by the exponent, n,more » by fitting the data to the power-law, Δλ = AT n. The exponent n varies non-monotonically with x, increasing to a maximum n = 2.5 for x = 0.079 and rapidly decreasing towards overdoped compositions to 1.6 for x = 0.131. This behavior is qualitatively similar to the doping evolution of the superconducting gap anisotropy in other iron pnictides, including hole-doped (Ba,K)Fe 2As 2 and 3d-electron-doped Ba(Fe,Co) 2As 2 superconductors, finding a full gap near optimal doping and strong anisotropy toward the ends of the superconducting dome in the T-x phase diagram. The normalized superfluid density in an optimally Rh-doped sample is almost identical to the temperature-dependence in the optimally doped Ba(Fe,Co) 2As 2 samples. In conclusion, our study supports the universal superconducting gap variation with doping and pairing at least in iron based superconductors of the BaFe 2As 2 family.« less
NASA Astrophysics Data System (ADS)
Kim, Hyunsoo; Tanatar, M. A.; Martin, C.; Blomberg, E. C.; Ni, Ni; Bud’ko, S. L.; Canfield, P. C.; Prozorov, R.
2018-06-01
Doping evolution of the superconducting gap anisotropy was studied in single crystals of 4d-electron doped Ba(Fe1‑x Rh x )2As2 using tunnel diode resonator measurements of the temperature variation of the London penetration depth . Single crystals with doping levels representative of an underdoped regime x = 0.039 ( K), close to optimal doping x = 0.057 ( K) and overdoped x = 0.079 ( K) and x = 0.131( K) were studied. Superconducting energy gap anisotropy was characterized by the exponent, n, by fitting the data to the power-law, . The exponent n varies non-monotonically with x, increasing to a maximum n = 2.5 for x = 0.079 and rapidly decreasing towards overdoped compositions to 1.6 for x = 0.131. This behavior is qualitatively similar to the doping evolution of the superconducting gap anisotropy in other iron pnictides, including hole-doped (Ba,K)Fe2As2 and 3d-electron-doped Ba(Fe,Co)2As2 superconductors, finding a full gap near optimal doping and strong anisotropy toward the ends of the superconducting dome in the T-x phase diagram. The normalized superfluid density in an optimally Rh-doped sample is almost identical to the temperature-dependence in the optimally doped Ba(Fe,Co)2As2 samples. Our study supports the universal superconducting gap variation with doping and pairing at least in iron based superconductors of the BaFe2As2 family.
Advanced analysis of thermal data observed in subsurface wells unmasks the ancient climate
NASA Astrophysics Data System (ADS)
Eppelbaum, Lev; Kutasov, Izzy
2014-05-01
Conventional methods of studying the ancient climate history are associated with statistical processing of accomplished meteorological data. These investigations have focused attention on meteorological records of air temperature, which can provide information on the only last 100-200 years. Number of the records is absolutely insufficient and their areal coverage is limited, some oldest meteorological stations may have been affected by local warming connected with urban and industrial growth. At the same time significant climate changes are accompanied by the corresponding variations in the Earth's surface (soil) temperature. This effect is based on the known physical law that temperature waves at the surface propagate downward into the subsurface with an amplitude attenuation and time delay increasing with depth. Earth's temperature profiles, measured by precise temperature logging T(z) in boreholes to depth of about 80-300 meters, have a 'memory' on what has happened on the surface during approximately several last centuries. Knowledge of the past climate in archaeology is necessary not only for tracing some ancient events and more deep understanding some historical facts, but also for estimation of past harvests, analysis of some physical conditions of different constructions built in the past, and in many other fields (Eppelbaum, 2010; Eppelbaum et al., 2010). The first attempts to recover the past ground surface temperature history (GSTH) from measured T(z) profiles date back to the mid-1960s, however only after Lachenbruch et al. (1988) pointed out that the magnitude and timing of the ground surface warming in Alaska is consistent with models of the recent warming, the method became popular (Cermak et al., 1996). Let us assume that tx years ago from now the ground surface temperature started to increase (warming) or reduce (cooling). Prior to this moment the subsurface temperature is: Ta(z,t = 0) = T0a + Γ z, (1) where T0a is the mean ground surface temperature at the moment of time t = 0 years; z is the vertical depth and Γ is the geothermal gradient. It is also assumed that the host medium is homogeneous with constant thermal properties. Now the current (t = tx) subsurface temperature is (in case of warming): Tc(z,t = tx) = T0c +f (z), (2) where T0c is the current (at the time (date) of temperature logging) mean ground surface temperature; and f(z) is a function of depth that could be obtained from the field data. In some cases the value of T0c can be obtained by extrapolation of the function Tc to z = 0. However, in most cases, the value T0c can be estimated by trial and error method: Assuming an interval of values for T0c, calculating for each T0c value of the temperature profiles Tcfor various models of change in the ground surface temperature (GST) with time and, finally, finding a best match between calculated and field measured Tc profiles. In our study we found that a quadratic regression can be utilized to estimate the value of T0c = a0 (Kutasov et al., 2000): Tc(z,t = tx) = a0 + a1z +a2z2, (3) where a0, a1, and a2 are the coefficients. We will consider four different models (Eppelbaum et al., 2006). Apparently each of these models is more suitable (applicable) under concrete physical-geological conditions. In the first model we assumed that txC years ago the GSTvalue suddenly changed from T0 to T0c. The current temperature anomaly (the reduced temperature) is TR (z) = T0c + f(z) - T0 - Γ z (4) and the solution is ( ) TRC = TR = ΔT0Φ *(x) -;z- ,t = txC, 2 at (5) ΔT0 = T0c - T0, (6)
Detection of nanoscale embedded layers using laboratory specular X-ray diffraction
DOE Office of Scientific and Technical Information (OSTI.GOV)
Beekman, Matt, E-mail: matt.beekman@oit.edu; Rodriguez, Gabriel; Atkins, Ryan
Unusual specular X-ray diffraction patterns have been observed from certain thin film intergrowths of metal monochalcogenide (MX) and transition metal dichalcogenide (TX{sub 2}) structures. These patterns exhibit selective “splitting” or broadening of selected (00l) diffraction peaks, while other (00l) reflections remain relatively unaffected [Atkins et al., Chem. Mater. 24, 4594 (2012)]. Using a simplified optical model in the kinematic approximation, we illustrate that these peculiar and somewhat counterintuitive diffraction features can be understood in terms of additional layers of one of the intergrowth components, MX or TX{sub 2}, interleaved between otherwise “ideal” regions of MX-TX{sub 2} intergrowth. The interpretation ismore » in agreement with scanning transmission electron microscope imaging, which reveals the presence of such stacking “defects” in films prepared from non-ideal precursors. In principle, the effect can be employed as a simple, non-destructive laboratory probe to detect and characterize ultrathin layers of one material, e.g., 2-dimensional crystals, embedded between two slabs of a second material, effectively using the two slabs as a highly sensitive interferometer of their separation distance.« less
Effect of the storage time and temperature on phenolic compounds of sorghum grain and flour.
Oliveira, Kênia Grasielle de; Queiroz, Valéria Aparecida Vieira; Carlos, Lanamar de Almeida; Cardoso, Leandro de Morais; Pinheiro-Sant'Ana, Helena Maria; Anunciação, Pamella Cristine; Menezes, Cícero Beserra de; Silva, Ernani Clarete da; Barros, Frederico
2017-02-01
This study evaluated the effect of storage temperature (4, 25 and 40°C) and time on the color and contents of 3-deoxyanthocyanins, total anthocyanins, total phenols and tannins of sorghum stored for 180days. Two genotypes SC319 (grain and flour) and TX430 (bran and flour) were analyzed. The SC319 flour showed luteolinidin and apigeninidin contents higher than the grain and the TX430 bran had the levels of all compounds higher than the flour. The storage temperature did not affect most of the analyzed variables. The content of most of the compounds reduced during the first 60days when they became stable. At day 180, the retention of the compounds in the genotypes SC319 and TX430 ranged from 56.1-77.9% and 67.3-80.1% (3-deoxyanthocyanins), 88.4-93.8% and 84.6-96.8% (total anthocyanins) and 86.7-86.8 and 89.4-100% (phenols) respectively. The retention of tannins ranged from 56.6 to 85.3%. The color of samples remained stable for 120days. Copyright © 2016 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Avetissov, Igor; Sadovskiy, Andrei; Belov, Stanislav; Kong Khan, Chan; Mozhevitina, Elena; Sukhanova, Ekaterina; Zharikov, Eugeniy
2014-09-01
T-x diagram of LiNO3-NaNO3 quasi-binary system has been improved using an original technique based on Raman measurements of condense phase. (LiNO3)x(NaNO3)1-x solid solution single crystal has been grown at different regimes of axial vibrational control (AVC) technique. Significant difference in segregation coefficient behavior between AVC-CZ and conventional CZ grown crystals has appeared: with AVC intensity increase the segregation coefficient (SC) raises for light molecular weight elements, SC reduces for medium molecular weight elements, and SC remains practically unchangeable for heavy molecular weight elements. Effect of vibrational intensity on vibron and optical characteristics, microhardness of AVC-CZ (LiNO3)x(NaNO3)1-x solid solution single crystals has been studied. For the AVC-CZ crystals has been observed increases in microhardness as well as in optical transmission up to 10 rel% compare to conventional CZ grown crystals.
Immersion Freezing of Coal Combustion Ash Particles from the Texas Panhandle
NASA Astrophysics Data System (ADS)
Whiteside, C. L.; Tobo, Y.; Mulamba, O.; Brooks, S. D.; Mirrielees, J.; Hiranuma, N.
2017-12-01
Coal combustion aerosol particles contribute to the concentrations of ice-nucleating particles (INPs) in the atmosphere. Especially, immersion freezing can be considered as one of the most important mechanisms for INP formation in supercooled tropospheric clouds that exist at temperatures between 0°C and -38°C. The U.S. contains more than 550 operating coal-burning plants consuming 7.2 x 108 metric tons of coal (in 2016) to generate a total annual electricity of >2 billion MW-h, resulting in the emission of at least 4.9 x 105 metric tons of PM10 (particulate matter smaller than 10 µm in diameter). In Texas alone, 19 combustion plants generate 0.15 billion MW-h electricity and >2.4 x 104 metric tons of PM10. Here we present the immersion freezing behavior of combustion fly ash and bottom ash particles collected in the Texas Panhandle region. Two types of particulate samples, namely <45 µm sieved bottom ash (B_Ash_TX_PH) and <45 µm sieved fly ash (F_Ash_TX_PH), were prepared. Afterwards, their immersion freezing abilities were measured using the Cryogenic Refrigerator Applied to Freezing Test (CRAFT) system covering the heterogeneous freezing temperature down to -30 °C. The results were generated and are reported through two metrics, frozen fraction, ffrozen(T), and ice nucleation active site density per unit mass, nm(T) as a function of temperature. Our preliminary results show that an onset increase in ffrozen(T) for B_Ash_TX_PH (ffrozen) occurred as high as at -15°C, whereas the onset for F_Ash_TX_PH is at -18°C. Secondly, B_Ash_TX_PH exhibited a higher nm(-20 °C) of 105 g-1 than that of F_Ash_TX_PH ( 5 x 103 g-1). On the other hand, previous studies on different combustion ash samples have reported that the opposite trend (i.e., ice nucleation efficiency of fly ash is greater than that of bottom ash; Grawe et al., 2016, ACP; Umo et al., 2015, ACP). We will discuss possible reasons for the observed differences. In addition, the results of complementary physico-chemical analyses via X-ray diffraction technique, Raman microscopy and scanning electron microscopy on both ash types will also be presented to relate the crystallographic and chemical properties to their ice nucleation abilities.
NASA Astrophysics Data System (ADS)
Li, Xing; Chen, Haishan; Wei, Jiangfeng; Hua, Wenjian; Sun, Shanlei; Ma, Hedi; Li, Xiao; Li, Jingping
2018-04-01
Land use and cover change (LUCC) is an important anthropogenic forcing of the climate system. Previous studies have demonstrated that LUCC significantly impacts both mean and extreme temperatures. In this study, we explored the multimodel performance of simulating LUCC-induced asymmetric effects on the different percentiles of maximum temperatures (Tmax) as well as the possible reasons for these effects using results from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Four state-of-art Earth system models (which provide the necessary data) are selected for investigating this issue. In general, all the cases of the model from the Geophysical Fluid Dynamics Laboratory show robust asymmetric responses between the 90th (TX90P) and 10th percentiles (TX10P) of Tmax, mainly due to cropland expansions, especially over India, the Sahel, and some parts of North America. However, weak and insignificant responses are shown for both the TX90P and TX10P in other models. The different changes in the Tmax variability among the models are primarily responsible for the occurrence of asymmetric features. Furthermore, by decomposing the Tmax changes over three typical regions, we analyze the potential causes for the inconsistencies among these models' results and find two crucial processes, that is, the repartitioning of the turbulent heat fluxes and the changes of the diurnal cycle variability due to LUCC. Whether these processes are pronounced determines the occurrence of the asymmetric Tmax responses. Overall, this study provides a critical clue for reducing the uncertainties of the LUCC effects on temperature extremes, which should be evaluated against observations.
Ma, Qi Yun; Zhang, Ji Quan; Lai, Quan; Zhang, Feng; Dong, Zhen Hua; A, Lu Si
2017-06-18
Fourteen extreme climatic indices related with main regional meteorological disasters and vegetation growth were calculated based on daily data from 13 meteorological stations during 1960-2014 in Songnen Grassland, Northeast China. Then, the variation trend and the spatial and temporal patterns of climatic extreme events were analyzed by using regression analysis, break trend analy-sis, Mann-Kendall test, Sen's slope estimator and moving t-test method. The results indicated that summer days (SU25), warm days (TX90P), warm nights (TN90P) and warm spell duration (WSDI) representing extremely high temperatures showed significant increasing trends (P<0.05). Meanwhile, frost days (FD0), cold days (TX10P), cold nights (TN10P) and cold spell duration indicator (CSDI) representing extremely low temperatures showed obviously decreasing trends. The magnitudes of changes in cold indices (FD0, TX10P, TN10P and CSDI) were clearly greater than those of warm indices (SU25, TX90P, TN90P and WSDI), and that changes in night indices were larger than those of day indices. Regional climate warming trend was obvious from 1970 to 2009, and the most occurrences of the abrupt changes in these indices were identified in this period. The extreme precipitation indices did not show obvious trend, in general, SDII and CDD experienced a slightly decreasing trend while RX5D, R95P, PRCPTOT and CWD witnessed a mildly increasing trend. It may be concluded that regional climate changed towards warming and slightly wetting in Songnen Grassland. The most sensitive region for extreme temperature was distributed in the south and north region. Additionally, the extreme temperature indices showed clearly spatial difference between the south and the north. As for the spatial variations of extreme precipitation indices, the climate could be characterized by becoming wetter in northern region, and getting drier in southern region, especially in southwestern region with a high drought risk.
Isolation and Characterization of a High Affinity Peptide Inhibitor of ClC-2 Chloride Channels*
Thompson, Christopher H.; Olivetti, Pedro R.; Fuller, Matthew D.; Freeman, Cody S.; McMaster, Denis; French, Robert J.; Pohl, Jan; Kubanek, Julia; McCarty, Nael A.
2009-01-01
The ClC protein family includes voltage-gated chloride channels and chloride/proton exchangers. In eukaryotes, ClC proteins regulate membrane potential of excitable cells, contribute to epithelial transport, and aid in lysosomal acidification. Although structure/function studies of ClC proteins have been aided greatly by the available crystal structures of a bacterial ClC chloride/proton exchanger, the availability of useful pharmacological tools, such as peptide toxin inhibitors, has lagged far behind that of their cation channel counterparts. Here we report the isolation, from Leiurus quinquestriatus hebraeus venom, of a peptide toxin inhibitor of the ClC-2 chloride channel. This toxin, GaTx2, inhibits ClC-2 channels with a voltage-dependent apparent KD of ∼20 pm, making it the highest affinity inhibitor of any chloride channel. GaTx2 slows ClC-2 activation by increasing the latency to first opening by nearly 8-fold but is unable to inhibit open channels, suggesting that this toxin inhibits channel activation gating. Finally, GaTx2 specifically inhibits ClC-2 channels, showing no inhibitory effect on a battery of other major classes of chloride channels and voltage-gated potassium channels. GaTx2 is the first peptide toxin inhibitor of any ClC protein. The high affinity and specificity displayed by this toxin will make it a very powerful pharmacological tool to probe ClC-2 structure/function. PMID:19574231
2017-07-24
Research Office Grant # W911NF-16-1-0276 PI: Keji Lai, University of Texas at Austin , Department of Physics, Austin , TX 78712 List of...at Austin 101 East 27th Street Suite 5.300 Austin , TX 78712 -1532 ABSTRACT Number of Papers published in peer-reviewed journals: Number of Papers...materials at the nanoscale. The work will establish a new research direction and augment existing DoD programs at UT- Austin . The research is of
Li, Rongfeng; Yu, Huahua; Xing, Ronge; Liu, Song; Qing, Yukun; Li, Kecheng; Li, Bing; Meng, Xiangtao; Cui, Jinhui; Li, Pengcheng
2013-09-01
Jellyfish venom contains various toxins and can cause itching, edema, muscle aches, shortness of breath, blood pressure depression, shock or even death after being stung. Hemolytic protein is one of the most hazardous components in the venom. The present study investigated the hemolytic activity of the nematocyst venom from jellyfish Stomolophus meleagris. Anion exchange chromatography, DEAE Sepharose Fast Flow, and gel filtration chromatography, Superdex200 had been employed to isolate hemolytic proteins from the nematocyst venom of jellyfish S. meleagris. Hemolysis of chicken red blood cells was used to quantify hemolytic potency of crude nematocyst venom and chromatography fractions during the purification process. Native-PAGE profile displayed one protein band in the purified hemolytic protein (SmTX); however, two protein bands with apparent molecular weights of ≈ 45 kDa and 52 kDa were observed in the reducing SDS-PAGE analysis. Approximately 70 μg/mL of SmTX caused 50% hemolysis (HU50) of the erythrocyte suspension. The hemolytic activity of SmTX was shown to be temperature and pH dependent, with the optimum temperature and pH being 37°C and pH 5.0. The present study is the first report of isolation and partial characterization of hemolytic proteins from the nematocyst venom of the jellyfish S. meleagris. The mechanism of the hemolytic activity of SmTX is not clear and deserves further investigation. Copyright © 2013. Published by Elsevier Ltd.
Nagy, Zoltan; Oliver-Taylor, Aaron; Kuehne, Andre; Goluch, Sigrun; Weiskopf, Nikolaus
2017-01-01
The transmit–receive (Tx/Rx) birdcage head coil is often used for excitation instead of the body coil because of the presumably lower risk of heating in and around conductive implants. However, this common practice has not been systematically tested. To investigate whether the Tx/Rx birdcage head coil produces less heating than the body coil when scanning individuals with implants, we used a 3T clinical scanner and made temperature measurements around a straight 15 cm conductor using either the Tx/Rx body or the head coil for excitation. Additionally, the transmitted fields of a Tx/Rx head coil were measured both in air and in gel using a resonant and a non-resonant B field probes as well as a non-resonant E field probe. Simulations using a finite-difference time domain solver were compared with the experimental findings. When the body coil was used for excitation, we observed heating around the 15 cm wire at various anatomical locations (both within and outside of the active volume of the head coil). Outside its active area, no such heating was observed while using the Tx/Rx head coil for excitation. The E and B fields of the Tx/Rx birdcage head coil extended well-beyond the physical dimensions of the coil. In air, the fields were monotonically decreasing, while in gel they were more complex with local maxima at the end of the ASTM phantom. These experimental findings were line with the simulations. While caution must always be exercised when scanning individuals with metallic implants, these findings support the use of the Tx/Rx birdcage head coil in place of the body coil at 3T in order to reduce the risk of heating in and around conductive implants that are remote from the head coil. PMID:28184184
Ji, Yiyi; Hoffmann, Werner; Pham, Michal; Dunn, Alexander E; Han, Haopeng; Özerdem, Celal; Waiczies, Helmar; Rohloff, Michael; Endemann, Beate; Boyer, Cyrille; Lim, May; Niendorf, Thoralf; Winter, Lukas
2018-04-01
To study the role of temperature in biological systems, diagnostic contrasts and thermal therapies, RF pulses for MR spin excitation can be deliberately used to apply a thermal stimulus. This application requires dedicated transmit/receive (Tx/Rx) switches that support high peak powers for MRI and high average powers for RF heating. To meet this goal, we propose a high-performance Tx/Rx switch based on positive-intrinsic-negative diodes and quarter-wavelength (λ/4) stubs. The λ/4 stubs in the proposed Tx/Rx switch design route the transmitted RF signal directly to the RF coil/antenna without passing through any electronic components (e.g., positive-intrinsic-negative diodes). Bench measurements, MRI, MR thermometry, and RF heating experiments were performed at f = 297 MHz (B 0 = 7 T) to examine the characteristics and applicability of the switch. The proposed design provided an isolation of -35.7dB/-41.5dB during transmission/reception. The insertion loss was -0.41dB/-0.27dB during transmission/reception. The switch supports high peak (3.9 kW) and high average (120 W) RF powers for MRI and RF heating at f = 297 MHz. High-resolution MRI of the wrist yielded image quality competitive with that obtained with a conventional Tx/Rx switch. Radiofrequency heating in phantom monitored by MR thermometry demonstrated the switch applicability for thermal modulation. Upon these findings, thermally activated release of a model drug attached to thermoresponsive polymers was demonstrated. The high-power Tx/Rx switch enables thermal MR applications at 7 T, contributing to the study of the role of temperature in biological systems and diseases. All design files of the switch will be made available open source at www.opensourceimaging.org. © 2018 International Society for Magnetic Resonance in Medicine.
Tuning the ground state of the Kondo lattice in UT Bi2 (T = Ag, Au) single crystals
NASA Astrophysics Data System (ADS)
Rosa, Priscila; Luo, Yongkang; Pagliuso, Pascoal; Bauer, Eric; Thompson, Joe; Fisk, Zachary
2015-03-01
Motivated by the interesting magnetic anisotropy found in the Ce-based heavy fermion family Ce TX2 (T = transition metal, X = pnictogen), here we study the novel U-based parent compounds U TBi2 (T = Ag, Au) by combining magnetization, electrical resistivity, and heat-capacity measurements. The single crystals, synthesized by the self-flux method, also crystallize in the tetragonal HfCuSi2-type structure (space group P4/nmm). Interestingly, although UAgBi2 is a low- γ antiferromagnet below TN = 181 K, UAuBi2 is a moderately heavy uniaxial ferromagnet below Tc = 22 K. Nevertheless, both compounds display the easy-magnetization direction along the c-axis and a large magnetocrystalline anisotropy. Our results point out to an incoherent Kondo behaviour in the paramagnetic state and an intricate competition between crystal field effects and two anisotropic exchange interactions, which lead to the remarkable difference in the observed ground states.
NASA Astrophysics Data System (ADS)
Zeng, Wei; Yu, Zhen; Li, Xilin
2018-04-01
Trend magnitudes of 14 indices of temperature extremes at 70 stations with elevations, latitude and Arctic Oscillation over northeast China during 1960-2011 are examined. There are no significant correlations between elevation and trend magnitudes with the exception of TXn (Min T max), TNn (Min T min), TR20 (tropical nights) and GSL (growing season length). Analysis of trend magnitudes by topographic type has a strong influence, which overrides that of degree of urbanization. By contrast, most of the temperature indices have stronger correlations with the latitude and Arctic Oscillation index. The correlations between the Arctic Oscillation index and percentile indices, including TX10p (cool days), TX90p (warm days), TN10p (cool nights), TN90p (warm nights), are not the same in different areas. To summarize, analysis of trend magnitudes by topographic type, the latitude and the Arctic Oscillation shows three factors to have a strong influence in this dataset, which overrides that of elevation and degree of urbanization.
McElcheran, Clare E.; Yang, Benson; Anderson, Kevan J. T.; Golenstani-Rad, Laleh; Graham, Simon J.
2015-01-01
Deep Brain Stimulation (DBS) is increasingly used to treat a variety of brain diseases by sending electrical impulses to deep brain nuclei through long, electrically conductive leads. Magnetic resonance imaging (MRI) of patients pre- and post-implantation is desirable to target and position the implant, to evaluate possible side-effects and to examine DBS patients who have other health conditions. Although MRI is the preferred modality for pre-operative planning, MRI post-implantation is limited due to the risk of high local power deposition, and therefore tissue heating, at the tip of the lead. The localized power deposition arises from currents induced in the leads caused by coupling with the radiofrequency (RF) transmission field during imaging. In the present work, parallel RF transmission (pTx) is used to tailor the RF electric field to suppress coupling effects. Electromagnetic simulations were performed for three pTx coil configurations with 2, 4, and 8-elements, respectively. Optimal input voltages to minimize coupling, while maintaining RF magnetic field homogeneity, were determined for all configurations using a Nelder-Mead optimization algorithm. Resulting electric and magnetic fields were compared to that of a 16-rung birdcage coil. Experimental validation was performed with a custom-built 4-element pTx coil. In simulation, 95-99% reduction of the electric field at the tip of the lead was observed between the various pTx coil configurations and the birdcage coil. Maximal reduction in E-field was obtained with the 8-element pTx coil. Magnetic field homogeneity was comparable to the birdcage coil for the 4- and 8-element pTx configurations. In experiment, a temperature increase of 2±0.15°C was observed at the tip of the wire using the birdcage coil, whereas negligible increase (0.2±0.15°C) was observed with the optimized pTx system. Although further research is required, these initial results suggest that the concept of optimizing pTx to reduce DBS heating effects holds considerable promise. PMID:26237218
McElcheran, Clare E; Yang, Benson; Anderson, Kevan J T; Golenstani-Rad, Laleh; Graham, Simon J
2015-01-01
Deep Brain Stimulation (DBS) is increasingly used to treat a variety of brain diseases by sending electrical impulses to deep brain nuclei through long, electrically conductive leads. Magnetic resonance imaging (MRI) of patients pre- and post-implantation is desirable to target and position the implant, to evaluate possible side-effects and to examine DBS patients who have other health conditions. Although MRI is the preferred modality for pre-operative planning, MRI post-implantation is limited due to the risk of high local power deposition, and therefore tissue heating, at the tip of the lead. The localized power deposition arises from currents induced in the leads caused by coupling with the radiofrequency (RF) transmission field during imaging. In the present work, parallel RF transmission (pTx) is used to tailor the RF electric field to suppress coupling effects. Electromagnetic simulations were performed for three pTx coil configurations with 2, 4, and 8-elements, respectively. Optimal input voltages to minimize coupling, while maintaining RF magnetic field homogeneity, were determined for all configurations using a Nelder-Mead optimization algorithm. Resulting electric and magnetic fields were compared to that of a 16-rung birdcage coil. Experimental validation was performed with a custom-built 4-element pTx coil. In simulation, 95-99% reduction of the electric field at the tip of the lead was observed between the various pTx coil configurations and the birdcage coil. Maximal reduction in E-field was obtained with the 8-element pTx coil. Magnetic field homogeneity was comparable to the birdcage coil for the 4- and 8-element pTx configurations. In experiment, a temperature increase of 2±0.15°C was observed at the tip of the wire using the birdcage coil, whereas negligible increase (0.2±0.15°C) was observed with the optimized pTx system. Although further research is required, these initial results suggest that the concept of optimizing pTx to reduce DBS heating effects holds considerable promise.
Role of five-fold symmetry in undercooled Al-Cu binary alloys
NASA Astrophysics Data System (ADS)
Pasturel, A.; Jakse, N.
2018-04-01
We investigate the role of five-fold symmetry (FFS) in undercooled Al1-xCux liquids (x = 0.3 and 0.4) using ab initio molecular dynamics simulations. We show that the structure factors and pair-correlation functions display characteristic features which are compatible with the occurrence of FFS and the emergence of a medium range order (MRO) below a temperature TX located close to the liquidus temperature. Then, we demonstrate that the formation of MRO is associated with a strong increase in local FFS-motifs which become more and more connected with decreasing temperature. From the temperature dependence of dynamic properties, we find that TX corresponds also to the onset of dynamic phenomena, like the non-Arrhenius temperature dependence of transport properties and the emergence of dynamical heterogeneities (DHs). Finally, we clearly identify a relationship between the fivefold topology at the medium-range scale (IMRO) and the spatial distribution of DHs using isoconfigurational ensemble simulations. This questions the direct role of the connectivity of five-fold-based motifs found in IMRO in nucleation of the parent crystalline ground states, namely, Al2Cu and Al3Cu2, which also display local ordering with a significant degree of FFS.
Brown, M D; Hendrikz, J K; Greenwood, J G; Kay, B H
1996-09-01
This study addressed biological control of peridomestic Aedes notoscriptus, known to be a highly effective colonizer of tire habitats and a possible vector of Ross River virus. A laboratory trial of the compatibility of the predators Mesocyclops aspericornis and Toxorhynchites speciosus in small container habitats showed that 4th-instar Tx. speciosus did not significantly affect M. aspericornis mortality. Introduced M. aspericornis and naturally occurring Tx. speciosus were found to form a compatible predator pair for reduction of larval Ae. notoscriptus and Culex quinquefasciatus populations in tire habitats. Over 22 months of field survey, 97% of tires without predators contained mosquito larvae, at a median density of 43 larvae/liter. By comparison, 51% of tires containing both predator species held mosquito larvae at a median density of 4 larvae/liter. Predation by Tx. speciosus persisted for the duration of the study. The inability of the Lake Kurwongbah strain of M. aspericornis to tolerate temperatures of < or = 10 degrees C, which are prevalent in Brisbane during winter, resulted in a failure to deliver persistent reduction of mosquitoes in tires. The temperature-dependent population characteristics of M. aspericornis emphasize the long-recognized importance of matching a biological control candidate's physiological requirements to the environment in which control is sought.
Fossil Groups as Cosmological Labs
NASA Astrophysics Data System (ADS)
D'Onghia, Elena
Optical and X-ray measurements of fossil groups (FGs) suggest that they are old and relaxed systems. If FGs are assembled at higher redshift, there is enough time for intermediate-luminosity galaxies to merge, resulting in the formation of the brightest group galaxy (BGG). We carry out the first, systematic study of a large sample of FGs, the "FOssil Group Origins'' (FOGO) based on an International Time Project at the Roque de los Muchachos Observatory. For ten FOGO FGs we have been awarded time at SUZAKU Telescope to measure the temperature of the hot intragroup gas (IGM). For these systems we plan to evaluate and correlate their X-ray luminosity and X-ray temperature, Lx-Tx, optical luminosity and X-ray temperature, Lopt-Tx, and group velocity dispersion with their X-ray temperature, sigma V-Tx, as compared to the non fossil systems. By combining these observations with state-of-art cosmological hydrodynamical simulations we will open a new window into the study of the IGM and the nature of fossil systems. Our proposed work will be of direct relevance for the understanding and interpretation of data from several NASA science missions. Specifically, the scaling relations obtained from these data combined with our predictions obtained using state-of-the-art hydrodynamical simulation numerical adopting a new hydrodynamical scheme will motivate new proposal on CHANDRA X-ray telescope for fossil groups and clusters. We will additionally create a public Online Planetarium Show. This will be an educational site, containing an interactive program called: "A Voyage to our Universe''. In the show we will provide observed images of fossil groups and similar images and movies obtained from the numerical simulations showing their evolution. The online planetarium show will be a useful reference and an interactive educational tool for both students and the public.
2014-01-01
RNA regulators are emerging as powerful tools to engineer synthetic genetic networks or rewire existing ones. A potential strength of RNA networks is that they may be able to propagate signals on time scales that are set by the fast degradation rates of RNAs. However, a current bottleneck to verifying this potential is the slow design-build-test cycle of evaluating these networks in vivo. Here, we adapt an Escherichia coli-based cell-free transcription-translation (TX-TL) system for rapidly prototyping RNA networks. We used this system to measure the response time of an RNA transcription cascade to be approximately five minutes per step of the cascade. We also show that this response time can be adjusted with temperature and regulator threshold tuning. Finally, we use TX-TL to prototype a new RNA network, an RNA single input module, and show that this network temporally stages the expression of two genes in vivo. PMID:24621257
NASA Astrophysics Data System (ADS)
Yao, C.; Mantegazzi, D.; Deschamps, F.; Sanchez-Valle, C.
2013-12-01
Methanol, CH3OH, has been recently observed in several comets and at the surface of Saturn's icy moon Enceladus, [Hodyss et al., 2009]. Its plausible presence in the subsurface ocean could significantly affect the thermal and structural evolution of the satellite [Deschamps et al., 2010]. Methanol lowers the melting temperature of water ice [Vuillard & Sanchez, 1961; Miller & Carpenter, 1964], hence decreasing the efficiency of convective heat transfer through the outer ice Ih shell, and affects the subsurface ocean density and thermo-chemical evolution. However, the phase diagram and the fluid density of the H2O - CH3OH system remains largely unknown at the high pressures and low temperature conditions relevant for the icy moon interiors. In this study, we determined experimentally the liquidus temperature of Ice Ih and Ice VI and the fluid density in the binary water-methanol system (5, 10 and 20 w% CH3OH) from sound velocity measurments by Brillouin scattering spectroscopy over the P-T range 230 - 300 K and 10-4 - 1.2 GPa. The experiments were conducted using a membrane-type diamond anvil cell (mDAC) and an in-house designed Peltier cooling system to achieve the low temperatures of interest. Melting and crystallization in the system was visually monitored and confirmed from changes in the Brillouin spectra and in the pressure dependence of the measured sound velocities. The density of fluids ρ(P, T,x) in the binary system weas determined from the inversion of sound velocities measured in the fluids as a function of pressure along isotherms from 230 to 300 K. The results are used to propose a thermodynamic model for the CH3OH-H2O system over the investigated P-T range and further used to examine the effect of the methanol on the crystallization and thermo-chemical evolution of the subsurface ocean. The implications of these results for the thermal and structural evolution of icy moons, with particular applications to Titan, will be further discussed. References : Deschamps, F., Mousis, O., Sanchez-Valle, C., and Lunine, J.I., Astrophys. J., 2010. Hodyss, R., Parkinson, C.D. Johnson, V.D., Stern, J.V., Goguen, J.D, Yung, Y.L., and Kanik, I., Geophys. Res. Lett., 1992. Miller, G.A., and Carpenter, D.A., J. Chem. Eng. Data, 1964. Vuillard, G., and Sanchez, M., Bull. Soc. Chim. France, 1961.
Ductless Mini-Split Heat Pump Comfort Evaluation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Roth, K.; Sehgal, N.; Akers, C.
2013-03-01
Field tests were conducted in two homes in Austin, TX, to evaluate the comfort performance of ductless minisplit heat pumps (DMSHPs), measuring temperature and relative humidity measurements in four rooms in each home before and after retrofitting a central HVAC system with DMSHPs.
Ductless Mini-Split Heat Pump Comfort Evaluation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Roth, K.; Sehgal, N.; Akers, C.
2013-03-01
Field tests were conducted in two homes in Austin, TX to evaluate the comfort performance of ductless mini-split heat pumps (DMSHPs), measuring temperature and relative humidity measurements in four rooms in each home before and after retrofitting a central HVAC system with DMSHPs.
ACCEPT 2: A public library of cluster properties
NASA Astrophysics Data System (ADS)
Donahue, Megan
2012-09-01
The current public ACCEPT database of cluster properties includes radial profiles of Tx, n_elec, entropy, and cooling time. We propose to more than double the current number of clusters in ACCEPT and to expand the current suite of properties to include uniformly measured profiles of gas mass and hydrostatic equilibrium mass along with signatures of dynamical relaxation (centroid shift, power ratios, surface brightness concentration, temperature ratios) and global quantities such as core-excised Tx, Lx, and metallicities. We will explore the relationship between cool cores and dynamical relaxation, the reliability of hydrostatic mass profiles, and the dependence of the gas mass fraction on halo mass, redshift, and the degree of relaxation. ACCEPT2 will enable further community science.
78 FR 72914 - Changes in Flood Hazard Determinations
Federal Register 2010, 2011, 2012, 2013, 2014
2013-12-04
.... Forest Hill, Hill, TX 76119. 3219 California Parkway, Forest Hill, TX 76119. Travis City of Austin (13..., Austin, TX Road, 12th 78767. Floor, Austin, TX 78704. Travis Unincorporated The Honorable Travis County..., 700 Austin, TX 78767. Lavaca Street, 5th Floor, Suite 540, Austin, TX 78701. Williamson City of...
Hanford Single Shell Tank Leak Causes and Locations - 241-TX Farm
DOE Office of Scientific and Technical Information (OSTI.GOV)
Girardot, C. L.; Harlow, D> G.
This document identifies 241-TX Tank Farm (TX Farm) leak causes and locations for the 100 series leaking tanks (241-TX-107 and 241-TX-114) identified in RPP-RPT-50870, Rev. 0, Hanford 241-TX Farm Leak Inventory Assessment Report. This document satisfies the TX Farm portion of the target (T04) in the Hanford Federal Facility Agreement and Consent Order milestone M-045-91F.
Comparison of Two Foreign Body Retrieval Devices with Adjustable Loops in a Swine Model
DOE Office of Scientific and Technical Information (OSTI.GOV)
Konya, Andras
2006-12-15
The purpose of the study was to compare two similar foreign body retrieval devices, the Texan{sup TM} (TX) and the Texan LONGhorn{sup TM} (TX-LG), in a swine model. Both devices feature a {<=}30-mm adjustable loop. Capture times and total procedure times for retrieving foreign bodies from the infrarenal aorta, inferior vena cava, and stomach were compared. All attempts with both devices (TX, n = 15; TX-LG, n = 14) were successful. Foreign bodies in the vasculature were captured quickly using both devices (mean {+-} SD, 88 {+-} 106 sec for TX vs 67 {+-} 42 sec for TX-LG) with nomore » significant difference between them. The TX-LG, however, allowed significantly better capture times than the TX in the stomach (p = 0.022), Overall, capture times for the TX-LG were significantly better than for the TX (p = 0.029). There was no significant difference between the total procedure times in any anatomic region. TX-LG performed significantly better than the TX in the stomach and therefore overall. The better torque control and maneuverability of TX-LG resulted in better performance in large anatomic spaces.« less
Aggregation study in mixture surfactant system TX-100+SDS in heavy water solutions by SANS method
NASA Astrophysics Data System (ADS)
Rajewska, A.; Islamov, A. Kh.; Bakeeva, R. F.
2018-03-01
The mixing of amphiphiles in water may lead to the formation of mixed micelles which often present new properties with respect to the pure component solutions [1,2]. The mixture system of classic surfactants SDS (sodium dodecyl sulfate)+TX-100(p-(1,1,3,3- tetramethyl) poly(oxyethylene) (anionic + non-ionic) in heavy water solutions was investigated at temperatures 30°, 50°, 70°C for compositions 1:1, 2:1, 3:1 by the small-angle neutron scattering(SANS) method on spectrometer (‘YuMO’) at the IBR-2 pulsed neutron source at FLNP, JINR in Dubna (Russia). Measurements have covered Q range from 8x10-3 to 0.4 Å-1. From the measured dependence of the scattered intensity on the scattering angle, we derived the size, shape of micelles, aggregation number at various compositions and temperatures. The size of mixed micelle is a weak function of the mixing ratio between the two components.
The analyses of extreme climate events over China based on CMIP5 historical and future simulations
NASA Astrophysics Data System (ADS)
Yang, S.; Dong, W.; Feng, J.; Chou, J.
2013-12-01
The extreme climate events have a serious influence on human society. Based on observations and 12 simulations from Coupled Model Intercomparison Project Phase 5 (CMIP5), Climatic extremes and their changes over china in history and future scenarios of three Representative Concentration Pathways (RCPs) are analyzed. Because of the background of global warming, in observations, the frost days (FD) and low-temperature threshold days (TN10P) have decreasing trend, and summer days (SU), high-temperature threshold days (TX90P), the heavy precipitation days (R20) and contribution of heavy precipitation days (P95T) show an increasing trend. Most coupled models can basically simulate main characteristics of most extreme indexes. The models reproduce the mean FD and TX90P value best and can give basic trends of the FD, TN10P, SU and TX90P. High correlation coefficients between simulated results and observation are found in FD, SU and P95T. For FD and SU index, most of the models have good ability to capture the spatial differences between the mean state of the 1986-2005 and 1961-1980 periods, but for other indexes, most of models' simulation ability for spatial disparity are not so satisfactory and have to be promoted. Under the high emission scenario of RCP8.5, the century-scale linear changes of Multi-Model Ensembles (MME) for FD, SU, TN10P, TX90P, R20 and P95T are -46.9, 46.0, -27.1, 175.4, 2.9 days and 9.9%, respectively. Due to the complexities of physical process parameterizations and the limitation of forcing data, a large uncertainty still exists in the simulations of climatic extremes. Fig.1 Observed and modeled multi-year average for each index (Dotted line: observation) Table1. Extreme index definition
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
Sadilkova, Lenka; Paluch, Zoltan; Mottlova, Jirina; Bednar, Frantisek; Alusik, Stefan
2012-01-01
Thromboxane B2 (TxB2) and particularly 11-dehydrothromboxane B2 (11-dTxB2) are widely used as prognostic risk markers of platelet activation in cardiovascular diseases. The main errors in TxB2 and 11-dTxB2 determination include either low concentrations of circulating TxB2 (1 - 2 pg/mL) and 11-dTxB2 (0.9 - 4.3 pg/mL) or rather high transiency (mean TxB2 half-life is approximately 5 minutes) as well as an incorrect pre-analytical phase set up. The aim of this study was to investigate the impact of a widely used purification step on the results of enzyme immunosorbent assay (EIA)--based measurement of the two selected thromboxanes. For the purpose of this study, 20 plasma samples (10 healthy donors, 10 patients under treatment with acetylsalicylic acid) were screened for TxB2 and 11-dTxB2 concentrations using commercial competitive EIA kits (Cayman Chemicals, Tallinn, Estonia; Neogen, Lexington, KY, USA) with or without the introduction of the purification procedure. The purification step does not significantly affect the results of EIA measurements of the two of TxA2 metabolites (TxB2, 11-dTxB2) in human plasma. The levels of TxB2 and 11-dTxB2 determined in the plasma samples were not significantly changed (p < 0.05) when the purification step was omitted compared to the purified samples. This study establishes a protocol allowing for reliable and reproducible plasma TxB2 and 11-dTxB2 EIA measurement for routine basic screening of platelet function.
Winter, Lukas; Özerdem, Celal; Hoffmann, Werner; Santoro, Davide; Müller, Alexander; Waiczies, Helmar; Seemann, Reiner; Graessl, Andreas; Wust, Peter; Niendorf, Thoralf
2013-01-01
This work demonstrates the feasibility of a hybrid radiofrequency (RF) applicator that supports magnetic resonance (MR) imaging and MR controlled targeted RF heating at ultrahigh magnetic fields (B0≥7.0T). For this purpose a virtual and an experimental configuration of an 8-channel transmit/receive (TX/RX) hybrid RF applicator was designed. For TX/RX bow tie antenna electric dipoles were employed. Electromagnetic field simulations (EMF) were performed to study RF heating versus RF wavelength (frequency range: 64 MHz (1.5T) to 600 MHz (14.0T)). The experimental version of the applicator was implemented at B0 = 7.0T. The applicators feasibility for targeted RF heating was evaluated in EMF simulations and in phantom studies. Temperature co-simulations were conducted in phantoms and in a human voxel model. Our results demonstrate that higher frequencies afford a reduction in the size of specific absorption rate (SAR) hotspots. At 7T (298 MHz) the hybrid applicator yielded a 50% iso-contour SAR (iso-SAR-50%) hotspot with a diameter of 43 mm. At 600 MHz an iso-SAR-50% hotspot of 26 mm in diameter was observed. RF power deposition per RF input power was found to increase with B0 which makes targeted RF heating more efficient at higher frequencies. The applicator was capable of generating deep-seated temperature hotspots in phantoms. The feasibility of 2D steering of a SAR/temperature hotspot to a target location was demonstrated by the induction of a focal temperature increase (ΔT = 8.1 K) in an off-center region of the phantom. Temperature simulations in the human brain performed at 298 MHz showed a maximum temperature increase to 48.6C for a deep-seated hotspot in the brain with a size of (19×23×32)mm3 iso-temperature-90%. The hybrid applicator provided imaging capabilities that facilitate high spatial resolution brain MRI. To conclude, this study outlines the technical underpinnings and demonstrates the basic feasibility of an 8-channel hybrid TX/RX applicator that supports MR imaging, MR thermometry and targeted RF heating in one device. PMID:23613896
Winter, Lukas; Özerdem, Celal; Hoffmann, Werner; Santoro, Davide; Müller, Alexander; Waiczies, Helmar; Seemann, Reiner; Graessl, Andreas; Wust, Peter; Niendorf, Thoralf
2013-01-01
This work demonstrates the feasibility of a hybrid radiofrequency (RF) applicator that supports magnetic resonance (MR) imaging and MR controlled targeted RF heating at ultrahigh magnetic fields (B0≥7.0T). For this purpose a virtual and an experimental configuration of an 8-channel transmit/receive (TX/RX) hybrid RF applicator was designed. For TX/RX bow tie antenna electric dipoles were employed. Electromagnetic field simulations (EMF) were performed to study RF heating versus RF wavelength (frequency range: 64 MHz (1.5T) to 600 MHz (14.0T)). The experimental version of the applicator was implemented at B0 = 7.0T. The applicators feasibility for targeted RF heating was evaluated in EMF simulations and in phantom studies. Temperature co-simulations were conducted in phantoms and in a human voxel model. Our results demonstrate that higher frequencies afford a reduction in the size of specific absorption rate (SAR) hotspots. At 7T (298 MHz) the hybrid applicator yielded a 50% iso-contour SAR (iso-SAR-50%) hotspot with a diameter of 43 mm. At 600 MHz an iso-SAR-50% hotspot of 26 mm in diameter was observed. RF power deposition per RF input power was found to increase with B0 which makes targeted RF heating more efficient at higher frequencies. The applicator was capable of generating deep-seated temperature hotspots in phantoms. The feasibility of 2D steering of a SAR/temperature hotspot to a target location was demonstrated by the induction of a focal temperature increase (ΔT = 8.1 K) in an off-center region of the phantom. Temperature simulations in the human brain performed at 298 MHz showed a maximum temperature increase to 48.6C for a deep-seated hotspot in the brain with a size of (19×23×32)mm(3) iso-temperature-90%. The hybrid applicator provided imaging capabilities that facilitate high spatial resolution brain MRI. To conclude, this study outlines the technical underpinnings and demonstrates the basic feasibility of an 8-channel hybrid TX/RX applicator that supports MR imaging, MR thermometry and targeted RF heating in one device.
The temperature of the Icelandic mantle from olivine-spinel aluminum exchange thermometry
NASA Astrophysics Data System (ADS)
Matthews, S.; Shorttle, O.; Maclennan, J.
2016-11-01
New crystallization temperatures for four eruptions from the Northern Volcanic Zone of Iceland are determined using olivine-spinel aluminum exchange thermometry. Differences in the olivine crystallization temperatures between these eruptions are consistent with variable extents of cooling during fractional crystallization. However, the crystallization temperatures for Iceland are systematically offset to higher temperatures than equivalent olivine-spinel aluminum exchange crystallization temperatures published for MORB, an effect that cannot be explained by fractional crystallization. The highest observed crystallization temperature in Iceland is 1399 ± 20°C. In order to convert crystallization temperatures to mantle potential temperature, we developed a model of multilithology mantle melting that tracks the thermal evolution of the mantle during isentropic decompression melting. With this model, we explore the controls on the temperature at which primary melts begin to crystallize, as a function of source composition and the depth from which the magmas are derived. Large differences (200°C) in crystallization temperature can be generated by variations in mantle lithology, a magma's inferred depth of origin, and its thermal history. Combining this model with independent constraints on the magma volume flux and the effect of lithological heterogeneity on melt production, restricted regions of potential temperature-lithology space can be identified as consistent with the observed crystallization temperatures. Mantle potential temperature is constrained to be 1480-30+37 °C for Iceland and 1318-32+44 °C for MORB.
NASA Astrophysics Data System (ADS)
Murugaiyan, Premkumar; Abhinav, Anand; Verma, Rahul; Panda, Ashis K.; Mitra, Amitava; Baysakh, Sandip; Roy, Rajat K.
2018-02-01
The effect of minor Al addition on structural, crystallization, soft magnetic behaviour and magnetic field induced anisotropy through DC Joule annealing in (Fe53.95Co29.05)83Si1.3B11.7-xNb3Cu1Alx, (X = 0, 1) alloys has been studied. The Al added as-quenched melt spun ribbons show good glass forming ability, better thermo-physical properties like a high Tx1 of 438 °C, Tcam of 435 °C and Tcnc of 906 °C, compared to Tx1 of 389 °C, Tcam of 409 °C and Tcnc of 900 °C for the alloy without Al addition. The longitudinal magnetic field annealed Al added alloy exhibits low Hc of 12.92 A/m and maximum Ms. of 1.78 T. The better soft magnetic properties of Al added alloy are achieved through a high nucleation density of BCC-FeCo(Al) nanocrystallites having low K1 and λ values. The as-quenched alloys possess high magneto-strain exceeding 30 ppm and approach near zero value on nanocrystallization. The longitudinal magnetic field assisted DC Joule annealing, having current density (J) in the range of J = 20-25 A/mm2 promotes good magnetic softening due to precipitation of 5-35 nm nanocrystallites as explained by extended-random anisotropy model. The Al added alloy shows better magnetic field induced anisotropy (Ku) on nanocrystallization and shows visible change in the shape of hysteresis loop.
An ignored variable: solution preparation temperature in protein crystallization.
Chen, Rui-Qing; Lu, Qin-Qin; Cheng, Qing-Di; Ao, Liang-Bo; Zhang, Chen-Yan; Hou, Hai; Liu, Yong-Ming; Li, Da-Wei; Yin, Da-Chuan
2015-01-19
Protein crystallization is affected by many parameters, among which certain parameters have not been well controlled. The temperature at which the protein and precipitant solutions are mixed (i.e., the ambient temperature during mixing) is such a parameter that is typically not well controlled and is often ignored. In this paper, we show that this temperature can influence protein crystallization. The experimental results showed that both higher and lower mixing temperatures can enhance the success of crystallization, which follows a parabolic curve with an increasing ambient temperature. This work illustrates that the crystallization solution preparation temperature is also an important parameter for protein crystallization. Uncontrolled or poorly controlled room temperature may yield poor reproducibility in protein crystallization.
Crystal growth and annealing method and apparatus
Gianoulakis, Steven E.; Sparrow, Robert
2001-01-01
A method and apparatus for producing crystals that minimizes birefringence even at large crystal sizes, and is suitable for production of CaF.sub.2 crystals. The method of the present invention comprises annealing a crystal by maintaining a minimal temperature gradient in the crystal while slowly reducing the bulk temperature of the crystal. An apparatus according to the present invention includes a thermal control system added to a crystal growth and annealing apparatus, wherein the thermal control system allows a temperature gradient during crystal growth but minimizes the temperature gradient during crystal annealing. An embodiment of the present invention comprises a secondary heater incorporated into a conventional crystal growth and annealing apparatus. The secondary heater supplies heat to minimize the temperature gradients in the crystal during the annealing process. The secondary heater can mount near the bottom of the crucible to effectively maintain appropriate temperature gradients.
Crystal growth and annealing for minimized residual stress
Gianoulakis, Steven E.
2002-01-01
A method and apparatus for producing crystals that minimizes birefringence even at large crystal sizes, and is suitable for production of CaF.sub.2 crystals. The method of the present invention comprises annealing a crystal by maintaining a minimal temperature gradient in the crystal while slowly reducing the bulk temperature of the crystal. An apparatus according to the present invention includes a thermal control system added to a crystal growth and annealing apparatus, wherein the thermal control system allows a temperature gradient during crystal growth but minimizes the temperature gradient during crystal annealing.
Antimicrobial and physical characteristics of orthodontic primers containing antimicrobial agents.
Chung, Shin-Hye; Cho, Soha; Kim, Kyungsun; Lim, Bum-Soon; Ahn, Sug-Joon
2017-03-01
To compare the antimicrobial and physical properties of experimental primers containing chlorhexidine (CHX) or ursolic acid (UA) with a commercial primer. Two antibacterial agents, 3 mg each of CHX and UA were incorporated respectively into 1 ml of Transbond XT primer (TX) to form antibacterial primers, TX-CHX and TX-UA. The antimicrobial activity of the three primers (TX, TX-CHX, and TX-UA) against Streptococcus mutans in both planktonic and biofilm phases was analyzed by determining minimum inhibitory and bactericidal concentrations and by performing growth and biofilm assays. Growth and biofilm assays were performed in both the absence and presence of thermocycling in a water tank to analyze the effects of water aging on the antimicrobial activities of primers. After bonding brackets onto bovine incisors using the primers, shear bond strength and mode of fracture were analyzed to compare physical properties. TX-CHX had stronger antimicrobial activity against S. mutans in the planktonic and biofilm phases than did TX or TX-UA. When applied, TX-CHX completely inhibited the growth and biofilm formation of S. mutans . In addition, the antimicrobial activity of TX-CHX was maintained after thermocycling. However, TX-UA did not show significant antimicrobial activity compared with TX. There was no significant difference in either shear bond strength or bond failure interface among the primers. Incorporation of CHX into an orthodontic primer may help prevent enamel demineralization around surfaces without compromising its physical properties.
Christensen, S; Pont-Kingdon, G; Carroll, D
2000-01-01
In the genome of the South African frog, Xenopus laevis, there are two complex families of transposable elements, Tx1 and Tx2, that have identical overall structures, but distinct sequences. In each family there are approximately 1500 copies of an apparent DNA-based element (Tx1D and Tx2D). Roughly 10% of these elements in each family are interrupted by a non-LTR retrotransposon (Tx1L and Tx2L). Each retrotransposon is flanked by a 23-bp target duplication of a specific D element sequence. In earlier work, we showed that the endonuclease domain (Tx1L EN) located in the second open reading frame (ORF2) of Tx1L encodes a protein that makes a single-strand cut precisely at the expected site within its target sequence, supporting the idea that Tx1L is a site-specific retrotransposon. In this study, we express the endonuclease domain of Tx2L (Tx2L EN) and compare the target preferences of the two enzymes. Each endonuclease shows some preference for its cognate target, on the order of 5-fold over the non-cognate target. The observed discrimination is not sufficient, however, to explain the observation that no cross-occupancy is observed - that is, L elements of one family have never been found within D elements of the other family. Possible sources of additional specificity are discussed. We also compare two hypotheses regarding the genome duplication event that led to the contemporary pseudotetraploid character of Xenopus laevis in light of the Tx1L and Tx2L data.
TxACOL workshop : Texas asphalt concrete overlay design and analysis system.
DOT National Transportation Integrated Search
2010-01-01
General Information: : -Two workshops were held respectively on Aug. 25 at Paris, Tx and on Oct. 6 at Austin, Tx, : -More than 30 representatives from TxDOT attended, : -Introduction of TxACOL software, key input parameters, and related lab and field...
An ignored variable: solution preparation temperature in protein crystallization
Chen, Rui-Qing; Lu, Qin-Qin; Cheng, Qing-Di; Ao, Liang-Bo; Zhang, Chen-Yan; Hou, Hai; Liu, Yong-Ming; Li, Da-Wei; Yin, Da-Chuan
2015-01-01
Protein crystallization is affected by many parameters, among which certain parameters have not been well controlled. The temperature at which the protein and precipitant solutions are mixed (i.e., the ambient temperature during mixing) is such a parameter that is typically not well controlled and is often ignored. In this paper, we show that this temperature can influence protein crystallization. The experimental results showed that both higher and lower mixing temperatures can enhance the success of crystallization, which follows a parabolic curve with an increasing ambient temperature. This work illustrates that the crystallization solution preparation temperature is also an important parameter for protein crystallization. Uncontrolled or poorly controlled room temperature may yield poor reproducibility in protein crystallization. PMID:25597864
76 FR 55883 - Procurement List; Proposed Addition
Federal Register 2010, 2011, 2012, 2013, 2014
2011-09-09
... . Research Park, 2301 Research Blvd., Bldg. 4, Austin, TX. Rundberg Building, 825 E. Rundberg Lane, Austin... Break Caf[eacute], 3651 S. IH-35, Austin, TX. Connection Warehouse, 2021 East Woodward, Austin, TX. Southpark G (CSB), 1821 Directors Blvd., Austin, TX. Southpark J, 2191 Woodward, Austin, TX. Southpark K...
Zhu, Xiao-Qing; Li, Xiu-Tao; Han, Su-Hui; Mei, Lian-Rui
2012-05-18
The effects of substituents on the temperature dependences of kinetic isotope effect (KIE) for the reactions of the hydride transfer from the substituted 5-methyl-6-phenyl-5,6-dihydrophenanthridine (G-PDH) to thioxanthylium (TX(+)) in acetonitrile were examined, and the results show that the temperature dependences of KIE for the hydride transfer reactions can be converted by adjusting the nature of the substituents in the molecule of the hydride donor. In general, electron-withdrawing groups can make the KIE to have normal temperature dependence, but electron-donating groups can make the KIE to have abnormal temperature dependence. Thermodynamic analysis on the possible pathways of the hydride transfer from G-PDH to TX(+) in acetonitrile suggests that the transfers of the hydride anion in the reactions are all carried out by the concerted one-step mechanism whether the substituent is an electron-withdrawing group or an electron-donating group. But the examination of Hammett-type free energy analysis on the hydride transfer reactions supports that the concerted one-step hydride transfer is not due to an elementary chemical reaction. The experimental values of KIE at different temperatures for the hydride transfer reactions were modeled by using a kinetic equation formed according to a multistage mechanism of the hydride transfer including a returnable charge-transfer complex as the reaction intermediate; the real mechanism of the hydride transfer and the root that why the temperature dependences of KIE can be converted as the nature of the substituents are changed were discovered.
A Regional Prototype for Obtaining and Evaluating Disease-Specific, Community-Level Data
2000-04-24
TEXAS Outlying Area GREGG TX TEXARKANA TX/ AR /OK HOUSTON TX TEXOMA TX/OK** JONESBORO AR TULSA OK KILLEEN TX ** VERNON LA** LAFAYETTE LA VICTORIA TX Next...appropriate setting and incur fewer costs for treatment (Litaker, 1996). The following questions may now be asked. How well are the communities within...and at times debilitating condition that tends to afflict young people who are otherwise healthy and productive. Migraine sufferers, who are
Computational Exploration of a Protein Receptor Binding Space with Student Proposed Peptide Ligands
King, Matthew D.; Phillips, Paul; Turner, Matthew W.; Katz, Michael; Lew, Sarah; Bradburn, Sarah; Andersen, Tim; Mcdougal, Owen M.
2017-01-01
Computational molecular docking is a fast and effective in silico method for the analysis of binding between a protein receptor model and a ligand. The visualization and manipulation of protein to ligand binding in three-dimensional space represents a powerful tool in the biochemistry curriculum to enhance student learning. The DockoMatic tutorial described herein provides a framework by which instructors can guide students through a drug screening exercise. Using receptor models derived from readily available protein crystal structures, docking programs have the ability to predict ligand binding properties, such as preferential binding orientations and binding affinities. The use of computational studies can significantly enhance complimentary wet chemical experimentation by providing insight into the important molecular interactions within the system of interest, as well as guide the design of new candidate ligands based on observed binding motifs and energetics. In this laboratory tutorial, the graphical user interface, DockoMatic, facilitates docking job submissions to the docking engine, AutoDock 4.2. The purpose of this exercise is to successfully dock a 17-amino acid peptide, α-conotoxin TxIA, to the acetylcholine binding protein from Aplysia californica-AChBP to determine the most stable binding configuration. Each student will then propose two specific amino acid substitutions of α-conotoxin TxIA to enhance peptide binding affinity, create the mutant in DockoMatic, and perform docking calculations to compare their results with the class. Students will also compare intermolecular forces, binding energy, and geometric orientation of their prepared analog to their initial α-conotoxin TxIA docking results. PMID:26537635
The unusual morphology of the intragroup medium in NGC 5171
NASA Astrophysics Data System (ADS)
Osmond, J. P. F.; Ponman, Trevor J.; Finoguenov, Alexis
2004-11-01
We present the results of a 24-ks XMM-Newton observation of the NGC 5171 group of galaxies. NGC 5171 is unusual in that it is an X-ray bright group (LX > 1042 erg s-1), with irregular contours which are not centred on a bright galaxy. The global spectrum is adequately described by a single-temperature APEC model with TX= 0.96 +/- 0.04 keV and Z= 0.13 +/- 0.02Zsolar, in good agreement with previous ROSAT data. We find that the X-ray contours are centred on a bright ridge of emission stretching from the brightest group galaxy to a nearby galaxy. Spectral mapping reveals this ridge to be both cool (TX~ 1.1 keV) and metallic (Z~ 0.4 Zsolar) in comparison to its surroundings, suggesting it is the result of a tidal interaction between the two galaxies. Optical data reveal the member galaxies to have a high velocity dispersion (σv= 494 +/- 99 km s-1) and a significantly non-Gaussian velocity distribution, suggesting that the group is in the process of merging. A region of hot gas with TX= 1.58 +/- 0.36 keV is found to the west of the bright central ridge, and we interpret this as shock-heating resulting from the merging. A further region of emission to the south-east of the bright central ridge, with TX= 1.14 +/- 0.13 keV, is probably associated with a background group, four times more distant.
A retrospective study of Class II mixed-dentition treatment.
Oh, Heesoo; Baumrind, Sheldon; Korn, Edward L; Dugoni, Steven; Boero, Roger; Aubert, Maryse; Boyd, Robert
2017-01-01
To consider the effectiveness of early treatment using one mixed-dentition approach to the correction of moderate and severe Class II malocclusions. Three groups of Class II subjects were included in this retrospective study: an early treatment (EarlyTx) group that first presented at age 7 to 9.5 years (n = 54), a late treatment (LateTx) group whose first orthodontic visit occurred between ages 12 and 15 (n = 58), and an untreated Class II (UnTx) group to assess the pretreatment comparability of the two treated groups (n = 51). Thirteen conventional cephalometric measurements were reported for each group and Class II molar severity was measured on the study casts of the EarlyTx and LateTx groups. Successful Class II correction was observed in approximately three quarters of both the EarlyTx group and the LateTx group at the end of treatment. EarlyTx patients had fewer permanent teeth extracted than did the LateTx patients (5.6% vs 37.9%, P < .001) and spent less time in full-bonded appliance therapy in the permanent dentition than did LateTx patients (1.7 ± 0.8 vs 2.6 ± 0.7years, P < .001). When supervision time is included, the EarlyTx group had longer total treatment time and averaged more visits than did the LateTx group (53.1 ± 18. 8 vs 33.7 ± 8.3, P < .0001). Fifty-five percent of the LateTx extraction cases involved removal of the maxillary first premolars only and were finished in a Class II molar relationship. EarlyTx comprehensive mixed-dentition treatment was an effective modality for early correction of Class II malocclusions.
20 CFR Appendix A to Subpart F of... - U.S. Seaports
Code of Federal Regulations, 2010 CFR
2010-04-01
... Port, LA New Orleans, LA Beaumont, TX Brownsville, TX Corpus Christi, TX Freeport, TX Galveston, TX..., MA Fall River, MA New Bedford, MA Providence, RI Bridgeport, CT New Haven, CT New London, CT Albany, NY New York, NY/NJ Camden, NJ Gloucester City, NJ Paulsboro, NJ Chester, PA Marcus Hook, PA...
Late renal transplant failure: an adverse prognostic factor at initiation of peritoneal dialysis.
Sasal, J; Naimark, D; Klassen, J; Shea, J; Bargman, J M
2001-01-01
Early renal transplant failure necessitating a return to dialysis has been shown to be a poor prognostic factor for survival. Little is known about the outcome of patients with late transplant failure returning to dialysis. It was our clinical impression that late transplant failure (>2 months) carries an increased morbidity and mortality risk in patients returning to dialysis. To determine whether patients with a failed renal transplant have an outcome different to those on dialysis who have never received a kidney transplant. Peritoneal dialysis (PD) unit in a teaching hospital. All failed renal transplant patients (fTx) in the Toronto Hospital Peritoneal Dialysis program between 1989 and 1996 were identified. This cohort of 42 fTx patients was compared with a cohort of randomly selected never-transplanted PD patients (non-Tx). The PD program was selected because of the availability of well-documented patient archival material. The non-Tx group was matched for age and presence of diabetes. Data were collected until retransplantation, change of dialysis modality or center, death, or until June 1998. There was no difference at initiation of PD between groups in serum albumin, residual renal function, or mean serum parathyroid hormone level. The mean low-density lipoprotein level was significantly higher in the fTx cohort. The duration of dialysis before Tx in fTx patients accounted for the increased total length of dialysis in fTx (mean 15 months). However, post-Tx the duration of PD was similar for both groups (30.7 months for fTx vs 31.6 months for non-Tx). The fTx group had a considerably worse outcome than the non-Tx group. The time to first peritonitis, subsequent episodes of peritonitis, catheter change, or transfer to hemodialysis occurred at a much faster rate in fTx patients. The most dramatic difference was in survival. There were 3 deaths in the non-Tx group and 12 in the fTx group (p < 0.01). The mean age at time of death in the fTx group was 47.5 years. Deaths were due mainly to gram-negative peritonitis and cardiovascular disease. We conclude that late failed renal transplant patients starting dialysis are at increased risk of complications and have strikingly higher mortality rates than non-Tx patients. A previously failed kidney transplant can be considered an adverse prognostic factor for patients commencing PD; these patients need to be closely monitored. Although this study was limited to PD patients, the same principles likely apply to fTx patients returning to any form of renal replacement therapy.
Simulation of the temperature distribution in crystals grown by Czochralski method
NASA Technical Reports Server (NTRS)
Dudokovic, M. P.; Ramachandran, P. A.
1985-01-01
Production of perfect crystals, free of residual strain and dislocations and with prescribed dopant concentration, by the Czochralski method is possible only if the complex, interacting phenomena that affect crystal growth in a Cz-puller are fully understood and quantified. Natural and forced convection in the melt, thermocapillary effect and heat transfer in and around the crystal affect its growth rate, the shape of the crystal-melt interface and the temperature gradients in the crystal. The heat transfer problem in the crystal and between the crystal and all other surfaces present in the crystal pulling apparatus are discussed at length. A simulation and computer algorithm are used, based on the following assumptions: (1) only conduction occurs in the crystal (experimentally determined conductivity as a function of temperature is used), (2) melt temperature and the melt-crystal heat transfer coefficient are available (either as constant values or functions of radial position), (3) pseudo-steady state is achieved with respect to temperature gradients, (4) crystal radius is fixed, and (5) both direct and reflected radiation exchange occurs among all surfaces at various temperatures in the crystal puller enclosure.
Goldfarb, Melanie; Parangi, Sareh; Yang, Jingyun; Ross, Douglas S.; Daniels, Gilbert H.
2012-01-01
Background Radioactive iodine lobe ablation (RAI-L-ABL) is a possible alternative to completion thyroidectomy (C-Tx) for follicular thyroid carcinoma (FTC), but no long-term outcome data are available after lobe ablation. We analyzed the long-term outcome of lobe ablation in a series of patients with FTC. Methods This was a retrospective study of patients who were treated with lobe ablation between 1983 and 2008. Of 134 patients with FTC, 37 (27.6%) had lobe ablation with 131I (30–32 mCi) (RAI-L-ABL), 68 (50.7%) had C-Tx, and 29 (21.6%) had initial total thyroidectomy (T-Tx). The main outcomes analyzed were 131I uptake after lobe ablation, C-Tx or T-Tx, serum thyroglobulin (Tg), serum thyroid-stimulating hormone (TSH), long-term disease-specific mortality, and disease-free survival. Results After lobe ablation, radioiodine uptake was significantly lower for the RAI-L-ABL group (0.6%) than for the C-Tx group (2.0%, p<0.005) or T-Tx group (1.3%, p=0.054). Subsequent remnant ablation was performed in 12 of 37 (32%) patients in the RAI-L-ABL group, in 58 of 68 (85.3%) patients in the C-Tx group, and in 25 of 29 (86.2%) patients in the T-Tx group (p<0.01). With median follow-up of 95 months for the RAI-L-ABL group, 47 months for the C-Tx group, and 53 months for the T-Tx group, there was one death in the RAI-L-ABL group and one death in the T-Tx group. No other RAI-L-ABL patients had detectable disease, whereas patients in the C-Tx group and two patients in the T-Tx group had detectable disease (p=0.18). Long-term stimulated or suppressed Tg of <1 ng/mL were found in 87.5% of the RAI-L-ABL group (n=28), 86.3% of the C-Tx group (n=57), and 77.8% of the T-Tx group (n=21). Tg was detectable in 40.6% of the RAI-L-ABL group compared to 13.8% of C-Tx and 28.6% of T-Tx groups (p<0.05, between groups). Conclusions RAI-L-ABL, C-Tx, and T-Tx are equally effective in achieving serum TSH concentrations of >25 mIU/L and preparing patients for conventional 131I treatment and whole body scanning with similar long-term outcomes. However, persistent measurable Tg (range 0.2–2.2 ng/mL) is more common after RAI-L-ABL. PMID:22385290
Apparatus and Methods for Locating Source of and Analyzing Electromagnetic Radiation
2015-11-19
President BY: ~~~~~~~~~~~==~----- CONTRACTOR’S OFFICIAL AND TITLE Nanohmics Inc 6201 E. Oltorf St., Suite 400 Austin , TX 78741 BUSINESS ADDRESS...ANALYZING ELECTROMAGNETIC RADIATION (71) Applicant: Nanohmics, Inc., Austin , TX (US) (72) Inventors: Byron G. Zollars, Georgetown, TX (US); Steve M...Savoy, Austin , TX (US); Michael W. Mayo, Austin , TX (US); Daniel R. Mitchell, Austin , TX (US) (21) Appl. No.: 14/531,247 (22) Filed: Nov. 3, 2014
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-09
... Giddings, TX, Giddings-Lee County, Takeoff Minimum and Obstacle DP, Orig Hebbronville, TX, Jim Hogg County, GPS RWY 13, Amdt 1A, CANCELLED Hebbronville, TX, Jim Hogg County, NDB RWY 13, Amdt 4 Hebbronville, TX, Jim Hogg County, RNAV (GPS) RWY 13, Orig Hebbronville, TX, Jim Hogg County, Takeoff Minimum and...
VizieR Online Data Catalog: XCS-DR1 Cluster Catalogue (Mehrtens+, 2012)
NASA Astrophysics Data System (ADS)
Mehrtens, N.; Romer, A. K.; Hilton, M.; Lloyd-Davies, E. J.; Miller, C. J.; Stanford, S. A.; Hosmer, M.; Hoyle, B.; Collins, C. A.; Liddle, A. R.; Viana, P. T. P.; Nichol, R. C.; Stott, J. P.; Dubois, E. N.; Kay, S. T.; Sahlen, M.; Young, O.; Short, C. J.; Christodoulou, L.; Watson, W. A.; Davidson, M.; Harrison, C. D.; Baruah, L.; Smith, M.; Burke, C.; Mayers, J. A.; Deadman, P.-J.; Rooney, P. J.; Edmondson, E. M.; West, M.; Campbell, H. C.; Edge, A. C.; Mann, R. G.; Sabirli, K.; Wake, D.; Benoist, C.; da Costa, L.; Maia, M. A. G.; Ogando, R.
2013-04-01
The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM-Newton Science Archive. Its main aims are to measure cosmological parameters and trace the evolution of X-ray scaling relations. In this paper we present the first data release from the XMM Cluster Survey (XCS-DR1). This consists of 503 optically confirmed, serendipitously detected, X-ray clusters. Of these clusters, 256 are new to the literature and 357 are new X-ray discoveries. We present 463 clusters with a redshift estimate (0.06
NASA Astrophysics Data System (ADS)
van den Besselaar, E. J. M.; Sanchez-Lorenzo, A.; Wild, M.; Klein Tank, A. M. G.
2012-04-01
The surface solar radiation (SSR) is the fundamental source of energy in the climate system, and consequently the source of life on our planet, due to its central role in the surface energy balance. Therefore, a significant impact on temperatures is expected due to the widespread dimming/brightening phenomenon observed since the second half of the 20th century (Wild, 2009). Previous studies pointed out the effects of SSR trends in temperatures series over Europe (Makowski et al., 2009; Philipona et al., 2009), although the lack of long-term SSR series limits these results. This work describes an updated sunshine duration (SS) dataset compiled by the European Climate Assessment and Dataset (ECA&D) project based on around 300 daily time series over Europe covering the 1961-2010 period. The relationship between the SS and temperature series is analysed based on four temperature variables: maximum (TX), minimum (TN) and mean temperature (TG), as well as the diurnal temperature range (DTR). Regional and pan-European mean series of SS and temperatures are constructed. The analyses are performed on annual and seasonal scale, and focusing on the interannual and decadal agreement between the variables. The results show strong positive correlations on interannual scales between SS and temperatures over Europe, especially for the DTR and TX during the summer period and regions in Central Europe. Interestingly, the SS and temperatures series show a tendency towards higher correlations in the smoothed series, both for different regions and temperature variables. These results confirm the relationship between temperature and SS trends over Europe since the second half of the 20th century, which has been speculated to partially decrease (increase) temperatures during the dimming (brightening) period (Makowski et al., 2009; Wild, 2009). Further research is needed to confirm this cause-effect relationship currently found only using correlation analysis.
1985-08-01
o10 ------- --------- tx] (26) t 5 t bE ho 2(h0+tx) 2 and as before 12 9 1 p ho + tx 2ho + 3tx bend3 + bE ho 2(ho+tX)2 txcos2 At the limit, as t...h0+tx) 2tx Therefore P 1 x P x lim 6 bend3 n2 -(-) - 4 -(;) t+o bE 3ho bE h 22 which, except for the sign, is the same as that arrived at in Eq. (9
Economic Impact Forecast System (EIFS) II: User’s Manual. Updated Edition.
1984-05-01
vermillion, in utica ny bea 18167 viga, in bOO bea 36011 cayuga. ny texarkana tx boa 36023 cortland, ny texarkana bea 36033 franklin, ny b119 bea...f1 48343 morris, tx 167 *.1• ’ texarkana tx boa (cont) tulsa ok boa (cont) 48387 red river, tx 40117 pawn*@, ok 48449 titus, tx 40119 payne, ok 40131...smsa texarkana ar smsa s7920 smsa texarkana tx smsa 29043 christian, ma texarkana sinsa 29077 green&, ma s8360 smsa 05081 little river, ar springfield
Beckmann, Sonja; Nikolic, Nataša; Denhaerynck, Kris; Binet, Isabelle; Koller, Michael; Boely, Elsa; De Geest, Sabina
2017-03-01
Obesity and weight gain are serious concerns after solid organ transplantation (Tx); however, no unbiased comparison regarding body weight parameter evolution across organ groups has yet been performed. Using data from the prospective nationwide Swiss Transplant Cohort Study, we compared the evolution of weight parameters up to 3 years post-Tx in 1359 adult kidney (58.3%), liver (21.7%), lung (11.6%), and heart (8.4%) recipients transplanted between May 2008 and May 2012. Changes in mean weight and body mass index (BMI) category were compared to reference values from 6 months post-Tx. At 3 years post-Tx, compared to other organ groups, liver Tx recipients showed the greatest weight gain (mean 4.8±10.4 kg), 57.4% gained >5% body weight, and they had the highest incidence of obesity (38.1%). After 3 years, based on their BMI categories at 6 months, normal weight and obese liver Tx patients, as well as underweight kidney, lung and heart Tx patients had the highest weight gains. Judged against international Tx patient data, the majority of our Swiss Tx recipients' experienced lower post-Tx weight gain. However, our findings show weight gain pattern differences, both within and across organ Tx groups that call for preventive measures. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
78 FR 48293 - Amendment of Class D and Class E Airspace; San Marcos, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2013-08-08
..., TX [Amended] San Marcos Municipal Airport, TX (Lat. 29[deg]53'34'' N., long. 97[deg]51'47'' W.) That...] San Marcos Municipal Airport, TX (Lat. 29[deg]53'34'' N., long. 97[deg]51'47'' W.) Lockhart Municipal Airport, TX (Lat. 29[deg]51'01'' N., long. 97[deg]40'21'' W.) That airspace extending upward from 700 feet...
TxDOT can help pave the way for distribution centers.
DOT National Transportation Integrated Search
2010-05-01
TxDOT supports economic development in Texas. : Working through its district offices, TxDOT can help : developers avoid common transportation-related : problems associated with selected center sites. TxDOT : may also be able to help distribution cent...
Nallapareddy, Sreedhar R; Singh, Kavindra V; Murray, Barbara E
2006-01-01
Inactivation by allelic exchange in clinical isolates of the emerging nosocomial pathogen Enterococcus faecium has been hindered by lack of efficient tools, and, in this study, transformation of clinical isolates was found to be particularly problematic. For this reason, a vector for allelic replacement (pTEX5500ts) was constructed that includes (i) the pWV01-based gram-positive repAts replication region, which is known to confer a high degree of temperature intolerance, (ii) Escherichia coli oriR from pUC18, (iii) two extended multiple-cloning sites located upstream and downstream of one of the marker genes for efficient cloning of flanking regions for double-crossover mutagenesis, (iv) transcriptional terminator sites to terminate undesired readthrough, and (v) a synthetic extended promoter region containing the cat gene for allelic exchange and a high-level gentamicin resistance gene, aph(2'')-Id, to distinguish double-crossover recombination, both of which are functional in gram-positive and gram-negative backgrounds. To demonstrate the functionality of this vector, the vector was used to construct an acm (encoding an adhesin to collagen from E. faecium) deletion mutant of a poorly transformable multidrug-resistant E. faecium endocarditis isolate, TX0082. The acm-deleted strain, TX6051 (TX0082Deltaacm), was shown to lack Acm on its surface, which resulted in the abolishment of the collagen adherence phenotype observed in TX0082. A mobilizable derivative (pTEX5501ts) that contains oriT of Tn916 to facilitate conjugative transfer from the transformable E. faecalis strain JH2Sm::Tn916 to E. faecium was also constructed. Using this vector, the acm gene of a nonelectroporable E. faecium wound isolate was successfully interrupted. Thus, pTEX5500ts and its mobilizable derivative demonstrated their roles as important tools by helping to create the first reported allelic replacement in E. faecium; the constructed this acm deletion mutant will be useful for assessing the role of acm in E. faecium pathogenesis using animal models.
78 FR 29613 - Modification and Revocation of Air Traffic Service Routes; Jackson, MS
Federal Register 2010, 2011, 2012, 2013, 2014
2013-05-21
... structure as required to preserve the safe and efficient flow of air traffic. Environmental Review The FAA... Guthrie 156[deg] and Millsap, TX, 274[deg] radials; Millsap; Glen Rose, TX; Cedar Creek, TX; Quitman, TX...
A Review of In Situ Observations of Crystallization and Growth in High Temperature Oxide Melts
NASA Astrophysics Data System (ADS)
Wang, Zhanjun; Sohn, Il
2018-05-01
This review summarizes the significant results of high-temperature confocal laser scanning microscopy (CLSM) and single hot thermocouple technology (SHTT) and its application in observing the crystallization and growth in high-temperature oxide melts from iron- and steel-making slags to continuous casting mold fluxes. Using in situ observations of CLSM and SHTT images of high-temperature molten oxides with time, temperature, and composition, the crystallization behavior, including crystal morphology, crystallization temperature, initial nucleation and growth rate, could be obtained. The broad range of applications using in situ observations during crystallization have provided a wealth of opportunities in pyrometallurgy and is provided in this review.
Source Hierarchy List. Volume 1. A through D
1994-07-01
TECHNOLOGY DIV 04 LAKE CITY ARMY AMMUNITION PLANT INDEPENDENCE MO INDUSTRIAL ENGINEERING DIV 03 LONE STAR ARMY AMMUNITION PLANT TEXARKANA TX 03...INDEPENDENCE MO INDUSTRIAL ENGINEERING DIV 03 LONE STAR ARMY AMMUNITION PLANT TEXARKANA TX 03 LONGHORN ARMY AMMUNITION PLANT MARSHALL TX 03 LOUISIANA...STORAGE ACTIVITY SAN ANTONIO TX* 02 COATING AND CHEMICAL LAB ABERDEEN PROVING GROUND MD 02 DARCOM INTERN TRAINING CENTER TEXARKANA TX 03 ARMY MATERIEL
Acute toxicity of karlotoxins to mice
Place, Allen R.; Munday, R.; Munday, J.S.
2015-01-01
Karlotoxins, polyketide derivatives produced by the dinoflagellate Karlodinium veneficum, are associated with fish kills in temperate estuaries world wide. In this study, the acute effects of 3 pure karlotoxin analogs (KmTx 1, KmTx 3 and KmTx 2) have been examined in mice. Transient lethargy and increased respiratory rates were observed soon after dosing with the karlotoxins by intraperitoneal injection, but no deaths were recorded in animals dosed with KmTx 2 at up to 500 μg/kg or with KmTx 1 or KmTx 3 at up to 4000 μg/kg. Animals dosed intraperitoneally with KmTx 1 and KmTx 3 at 4000 μg/kg showed a pronounced decrease in food and water intake, lasting 3–4 days after dosing, accompanied by a significant decrease in body weight. After this time, the lost body weight was regained and the behavior and appearance of the mice remained normal throughout the following 10 day observation period. No effects were seen in mice dosed orally with KmTx 1 or KmTx 3 at a dose of 4000 μg/kg. It is concluded that contamination of seafood if it were to occur with these karlotoxins is unlikely to pose a major risk of acute intoxication in consumers. PMID:25150200
Effects of cooling interval and MnO2, TiO2, CdO, NiO additions on spheluritic willemite crystals
NASA Astrophysics Data System (ADS)
Coşkun, Nihal Derin; Uz, Veli; Issi, Ali; Genç, Soner; Çakı, Münevver
2017-01-01
Macro crystal production in crystal glaze systems is a very important topic in ceramic art and science. In this study, crystal growth was obtained in two different firing regimes. Recipes were prepared by adding MnO, TiO, NiO and CdO into the frit. The first firing regime, which is used in artistic ceramics, has a 100 °C cooling temperature interval. The second regime that has a 580 °C cooling temperature interval, was determined by DTA analysis. Then, the development of crystals was compared between these two firing regimes. According to the results, spheluritic willemite crystals up to three cm in the glazes doped MnO2 have been obtained by cooling it in a wide cooling interval. Larger willemite crystals were not formed in the narrow cooling temperature interval. It was determined that larger crystals can be produced by cooling at wide cooling temperature intervals and holding at lower temperature which involves nucleating the temperature of the crystal.
Debranching and temperature-cycled crystallization of waxy rice starch and their digestibility.
Zeng, Feng; Ma, Fei; Gao, Qunyu; Yu, Shujuan; Kong, Fansheng; Zhu, Siming
2014-11-26
Slowly digestible starch (SDS) was obtained through debranched waxy rice starch and subsequent crystallization under isothermal and temperature-cycled conditions. Temperature-cycled crystallization of dual 4/-20 °C produced a higher yield of SDS product than isotherm crystallization. Crystal structure of SDS products changed from A-type to a mixture of B and V-type X-ray diffraction patterns. The relative crystallinity was higher in the temperature-cycled samples than that of isotherm. Attenuated total reflectance Fourier transform infrared spectroscopy suggested that the peripheral regions of isothermal storage starch were better organized than temperature-cycles. Temperature cycling induced higher onset temperature for melting of crystals than isothermal storage under a differential scanning calorimeter. The cycled temperature storage induced a greater amount of SDS than the isothermal storage. Copyright © 2014 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Dvorak, Steven L.; Sternberg, Ben K.; Feng, Wanjie
2017-03-01
In this paper we discuss the design and verification of wide-band, multi-frequency, tuning circuits for large-moment Transmitter (TX) loops. Since these multi-frequency, tuned-TX loops allow for the simultaneous transmission of multiple frequencies at high-current levels, they are ideally suited for frequency-domain geophysical systems that collect data while moving, such as helicopter mounted systems. Furthermore, since multi-frequency tuners use the same TX loop for all frequencies, instead of using separate tuned-TX loops for each frequency, they allow for the use of larger moment TX loops. In this paper we discuss the design and simulation of one- and three-frequency tuned TX loops and then present measurement results for a three-frequency, tuned-TX loop.
Kachel, Hamid S.; Patel, Rohit N.; Franzyk, Henrik; Mellor, Ian R.
2016-01-01
Philanthotoxin-433 (PhTX-433) is an active component of the venom from the Egyptian digger wasp, Philanthus triangulum. PhTX-433 inhibits several excitatory ligand-gated ion channels, and to improve selectivity two synthetic analogues, PhTX-343 and PhTX-12, were developed. Previous work showed a 22-fold selectivity of PhTX-12 over PhTX-343 for embryonic muscle-type nicotinic acetylcholine receptors (nAChRs) in TE671 cells. We investigated their inhibition of different neuronal nAChR subunit combinations as well as of embryonic muscle receptors expressed in Xenopus oocytes. Whole-cell currents in response to application of acetylcholine alone or co-applied with PhTX analogue were studied by using two-electrode voltage-clamp. α3β4 nAChRs were most sensitive to PhTX-343 (IC50 = 12 nM at −80 mV) with α4β4, α4β2, α3β2, α7 and α1β1γδ being 5, 26, 114, 422 and 992 times less sensitive. In contrast α1β1γδ was most sensitive to PhTX-12 along with α3β4 (IC50 values of 100 nM) with α4β4, α4β2, α3β2 and α7 being 3, 3, 26 and 49 times less sensitive. PhTX-343 inhibition was strongly voltage-dependent for all subunit combinations except α7, whereas this was not the case for PhTX-12 for which weak voltage dependence was observed. We conclude that PhTX-343 mainly acts as an open-channel blocker of nAChRs with strong subtype selectivity. PMID:27901080
Computational exploration of a protein receptor binding space with student proposed peptide ligands.
King, Matthew D; Phillips, Paul; Turner, Matthew W; Katz, Michael; Lew, Sarah; Bradburn, Sarah; Andersen, Tim; McDougal, Owen M
2016-01-01
Computational molecular docking is a fast and effective in silico method for the analysis of binding between a protein receptor model and a ligand. The visualization and manipulation of protein to ligand binding in three-dimensional space represents a powerful tool in the biochemistry curriculum to enhance student learning. The DockoMatic tutorial described herein provides a framework by which instructors can guide students through a drug screening exercise. Using receptor models derived from readily available protein crystal structures, docking programs have the ability to predict ligand binding properties, such as preferential binding orientations and binding affinities. The use of computational studies can significantly enhance complimentary wet chemical experimentation by providing insight into the important molecular interactions within the system of interest, as well as guide the design of new candidate ligands based on observed binding motifs and energetics. In this laboratory tutorial, the graphical user interface, DockoMatic, facilitates docking job submissions to the docking engine, AutoDock 4.2. The purpose of this exercise is to successfully dock a 17-amino acid peptide, α-conotoxin TxIA, to the acetylcholine binding protein from Aplysia californica-AChBP to determine the most stable binding configuration. Each student will then propose two specific amino acid substitutions of α-conotoxin TxIA to enhance peptide binding affinity, create the mutant in DockoMatic, and perform docking calculations to compare their results with the class. Students will also compare intermolecular forces, binding energy, and geometric orientation of their prepared analog to their initial α-conotoxin TxIA docking results. © 2015 The International Union of Biochemistry and Molecular Biology.
Nôga, Diana Aline Morais Ferreira; Brandão, Luiz Eduardo Mateus; Cagni, Fernanda Carvalho; Silva, Delano; de Azevedo, Dina Lilia Oliveira; Araújo, Arrilton; Dos Santos, Wagner Ferreira; Miranda, Antonio; da Silva, Regina Helena; Ribeiro, Alessandra Mussi
2016-12-23
Natural products, sources of new pharmacological substances, have large chemical diversity and architectural complexity. In this context, some toxins obtained from invertebrate venoms have anticonvulsant effects. Epilepsy is a neurological disorder that affects about 65 million people worldwide, and approximately 30% of cases are resistant to pharmacological treatment. Previous studies from our group show that the denatured venom of the ant Dinoponera quadriceps (Kempt) protects mice against bicuculline (BIC)-induced seizures and death. The aim of this study was to investigate the anticonvulsant activity of compounds isolated from D. quadriceps venom against seizures induced by BIC in mice. Crude venom was fractionated by high-performance liquid chromatography (HPLC) resulting in six fractions referred to as DqTx1-DqTx6. A liquid chromatography-mass spectrometry (LC/MS) analysis revealed a major 431 Da compound in fractions DqTx1 and DqTx2. Fractions DqTx3 and DqTx4 showed a compound of 2451 Da and DqTx5 revealed a 2436 Da compound. Furthermore, the DqTx6 fraction exhibited a major component with a molecular weight of 13,196 Da. Each fraction (1 mg/mL) was microinjected into the lateral ventricle of mice, and the animals were observed in an open field. We did not observe behavioral alterations when the fractions were given alone. Conversely, when the fractions were microinjected 20 min prior to the administration of BIC (21.6 nM), DqTx1, DqTx4, and DqTx6 fractions increased the latency for onset of tonic-clonic seizures. Moreover, all fractions, except DqTx5, increased latency to death. The more relevant result was obtained with the DqTx6 fraction, which protected 62.5% of the animals against tonic-clonic seizures. Furthermore, this fraction protected 100% of the animals from seizure episodes followed by death. Taken together, these findings indicate that compounds from ant venom might be a potential source of new anticonvulsants molecules.
Margatoxin-bound quantum dots as a novel inhibitor of the voltage-gated ion channel Kv1.3.
Schwartz, Austin B; Kapur, Anshika; Wang, Wentao; Huang, Zhenbo; Fardone, Erminia; Palui, Goutam; Mattoussi, Hedi; Fadool, Debra Ann
2017-02-01
Venom-derived ion channel inhibitors have strong channel selectivity, potency, and stability; however, tracking delivery to their target can be challenging. Herein, we utilized luminescent quantum dots (QDs) conjugated to margatoxin (MgTx) as a traceable vehicle to target a voltage-dependent potassium channel, Kv1.3, which has a select distribution and well-characterized role in immunity, glucose metabolism, and sensory ability. We screened both unconjugated (MgTx) and conjugated MgTx (QD-MgTx) for their ability to inhibit Shaker channels Kv1.1 to Kv1.7 using patch-clamp electrophysiology in HEK293 cells. Our data indicate that MgTx inhibits 79% of the outward current in Kv1.3-transfected cells and that the QD-MgTx conjugate is able to achieve a similar level of block, albeit a slightly reduced efficacy (66%) and at a slower time course (50% block by 10.9 ± 1.1 min, MgTx; vs. 15.3 ± 1.2 min, QD-MgTx). Like the unbound peptide, the QD-MgTx conjugate inhibits both Kv1.3 and Kv1.2 at a 1 nM concentration, whereas it does not inhibit other screened Shaker channels. We tested the ability of QD-MgTx to inhibit native Kv1.3 expressed in the mouse olfactory bulb (OB). In brain slices of the OB, the conjugate acted similarly to MgTx to inhibit Kv1.3, causing an increased action potential firing frequency attributed to decreased intraburst duration rather than interspike interval. Our data demonstrate a retention of known biophysical properties associated with block of the vestibule of Kv1.3 by QD-MgTx conjugate compared to that of MgTx, inferring QDs could provide a useful tool to deliver ion channel inhibitors to targeted tissues in vivo. © 2016 International Society for Neurochemistry.
Platelet aggregation caused by a partially purified jellyfish toxin from Carybdea rastonii.
Azuma, H; Sekizaki, S; Satoh, A; Nakajima, T; Ishikawa, M
1986-01-01
A partially purified toxin (pCrTX) was obtained from the tentacles of the jellyfish, Carybdea rastonii. When pCrTX (3 X 10(-8) - 3 X 10(-7) g/ml) was added to citrated platelet-rich plasma, aggregation was produced in a concentration-dependent manner. Scanning electron microscopic examination revealed that both pCrTX and collagen produced aggregates of platelets possessing many pseudopods. The concentration which produced 50% aggregation for pCrTX was 1.8 X 10(-7) g/ml, as compared to 2.3 X 10(-6) g/ml for collagen. The pCrTX-induced aggregation was only slightly inhibited by indomethacin and quinacrine in concentrations sufficient to inhibit arachidonic acid- and collagen-induced aggregation. pCrTX was less active in washed platelets suspended in Ca2+ free medium, whereas the pCrTX-induced aggregation was significantly augmented in the presence of Ca2+. The augmentation of aggregation by Ca2+ was only slightly attenuated by pretreatment with 100 microM verapamil. pCrTX significantly increased the concentration of cytoplasmic free Ca2+ ([Ca2+]i) and depolarized the platelet membrane in concentrations that produced aggregation. The increase in [Ca2+]i caused by pCrTX was little affected by verapamil. The depolarization by pCrTX was unchanged in the presence or absence of Ca2+, or by sodium or potassium transport inhibitors. The movement of 22Na+ into platelets was significantly increased by pCrTX. This increase in the movement of 22N+ into platelets was unaffected by tetrodotoxin. On the other hand, pCrTX-induced aggregation, depolarization and the increase in [Ca2+]i were all significantly attenuated in low Na+ medium. These results suggest that pCrTX causes a massive depolarization by increasing cation permeability indiscriminately and this generalized depolarization permits an inward movement of calcium down an electrochemical gradient which, in turn triggers platelet aggregation.
76 FR 70422 - Procurement List Additions
Federal Register 2010, 2011, 2012, 2013, 2014
2011-11-14
...., Austin, TX Research Park, 2301 Research Blvd., Bldg. 4, Austin, TX Rundberg Building, 825 E. Rundberg...., Austin, TX 53 North Sixth Street, New Bedford, MA 75 Perseverance Way, Hyannis, MA One Montvale Ave... Center & Tax Break Caf[eacute], 3651 S. IH-35, Austin, TX Connection Warehouse, 2021 East Woodward...
DOE Office of Scientific and Technical Information (OSTI.GOV)
Marra, James; Kim, Dong -Sang; Maio, Vincent
A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JHCM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these “troublesome" waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approaches to mitigate the impacts of crystallization so that increases in waste loading can be realized. Advancedmore » glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating.The Hanford site AZ-101 tank waste composition represents a waste group that is waste loading limited primarily due to high concentrations of Fe 2O 3 (also with high Al 2O 3 concentrations). Systematic glass formulation development utilizing slightly higher process temperatures and higher tolerance to spinel crystals demonstrated that an increase in waste loading of more than 20% could be achieved for this waste composition, and by extension higher loadings for wastes in the same group. An extended duration CCIM melter test was conducted on an AZ-101 waste simulant using the CCIM platform at the Idaho National Laboratory (INL). The melter was continually operated for approximately 80 hours demonstrating that the AZ-101 high waste loading glass composition could be readily processed using the CCIM technology. The resulting glass was close to the targeted composition and exhibited excellent durability in both the as poured state and after being slowly cooled according to the canister centerline cooling (CCC) profile. Glass formulation development was also completed on other Hanford tank wastes that were identified to further challenge waste loading due to the presence of appreciable quantities (>750 g) of plutonium in the waste tanks. In addition to containing appreciable Pu quantities, the C-102 waste tank and the 244-TX waste tank contain high concentrations of aluminum and iron, respectively that will further challenge vitrification processing. Glass formulation testing also demonstrated that high waste loadings could be achieved with these tank compositions using the attributes afforded by the CCIM technology.« less
Reis, Pablo V M; Boff, Daiane; Verly, Rodrigo M; Melo-Braga, Marcella N; Cortés, María E; Santos, Daniel M; Pimenta, Adriano M de C; Amaral, Flávio A; Resende, Jarbas M; de Lima, Maria E
2018-01-01
The antimicrobial peptide LyeTxI isolated from the venom of the spider Lycosa erythrognatha is a potential model to develop new antibiotics against bacteria and fungi. In this work, we studied a peptide derived from LyeTxI, named LyeTxI-b, and characterized its structural profile and its in vitro and in vivo antimicrobial activities. Compared to LyeTxI, LyeTxI-b has an acetylated N-terminal and a deletion of a His residue, as structural modifications. The secondary structure of LyeTxI-b is a well-defined helical segment, from the second amino acid to the amidated C-terminal, with no clear partition between hydrophobic and hydrophilic faces. Moreover, LyeTxI-b shows a potent antimicrobial activity against Gram-positive and Gram-negative planktonic bacteria, being 10-fold more active than the native peptide against Escherichia coli. LyeTxI-b was also active in an in vivo model of septic arthritis, reducing the number of bacteria load, the migration of immune cells, the level of IL-1β cytokine and CXCL1 chemokine, as well as preventing cartilage damage. Our results show that LyeTxI-b is a potential therapeutic model for the development of new antibiotics against Gram-positive and Gram-negative bacteria.
Reis, Pablo V. M.; Boff, Daiane; Verly, Rodrigo M.; Melo-Braga, Marcella N.; Cortés, María E.; Santos, Daniel M.; Pimenta, Adriano M. de C.; Amaral, Flávio A.; Resende, Jarbas M.; de Lima, Maria E.
2018-01-01
The antimicrobial peptide LyeTxI isolated from the venom of the spider Lycosa erythrognatha is a potential model to develop new antibiotics against bacteria and fungi. In this work, we studied a peptide derived from LyeTxI, named LyeTxI-b, and characterized its structural profile and its in vitro and in vivo antimicrobial activities. Compared to LyeTxI, LyeTxI-b has an acetylated N-terminal and a deletion of a His residue, as structural modifications. The secondary structure of LyeTxI-b is a well-defined helical segment, from the second amino acid to the amidated C-terminal, with no clear partition between hydrophobic and hydrophilic faces. Moreover, LyeTxI-b shows a potent antimicrobial activity against Gram-positive and Gram-negative planktonic bacteria, being 10-fold more active than the native peptide against Escherichia coli. LyeTxI-b was also active in an in vivo model of septic arthritis, reducing the number of bacteria load, the migration of immune cells, the level of IL-1β cytokine and CXCL1 chemokine, as well as preventing cartilage damage. Our results show that LyeTxI-b is a potential therapeutic model for the development of new antibiotics against Gram-positive and Gram-negative bacteria. PMID:29681894
Temperature cycling vapor deposition HgI.sub.2 crystal growth
Schieber, Michael M.; Beinglass, Israel; Dishon, Giora
1977-01-01
A method and horizontal furnace for vapor phase growth of HgI.sub.2 crystals which utilizes controlled axial and radial airflow to maintain the desired temperature gradients. The ampoule containing the source material is rotated while axial and radial air tubes are moved in opposite directions during crystal growth to maintain a desired distance and associated temperature gradient with respect to the growing crystal, whereby the crystal interface can advance in all directions, i.e., radial and axial according to the crystallographic structure of the crystal. Crystals grown by this method are particularly applicable for use as room-temperature nuclear radiation detectors.
75 FR 31677 - Amendment of Class E Airspace; Corpus Christi, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-04
...-0089; Airspace Docket No. 10-ASW-1] Amendment of Class E Airspace; Corpus Christi, TX AGENCY: Federal... the Corpus Christi, TX area. Additional controlled airspace is necessary to accommodate new Standard... E airspace for the Corpus Christi, TX area, reconfiguring controlled airspace at Aransas County...
Federal Register 2010, 2011, 2012, 2013, 2014
2013-01-30
... ALLEN HA 2301 JASMINE AVE, MC ALLEN, TX 80 336,384 78501. VA: ALEXANDRIA REDEV & HA 600 N FAIRFAX ST... ANTONIO, TX 0 19,600 78295. TX: MC ALLEN HA 2301 JASMINE AVE, MC ALLEN, TX 0 15,800 78501. VA: ALEXANDRIA...
76 FR 44254 - Amendment of Class D Airspace; Denton, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-07-25
...-1327; Airspace Docket No. 10-ASW-19] Amendment of Class D Airspace; Denton, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class D airspace for Denton, TX, to... rulemaking to amend Class D airspace for Denton, TX, creating additional controlled airspace at Denton...
75 FR 15360 - Proposed Amendment of Class E Airspace; Austin, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-03-29
...-1152; Airspace Docket No. 09-ASW-31] Proposed Amendment of Class E Airspace; Austin, TX AGENCY: Federal... proposes to amend Class E airspace in the Austin, TX area. Additional controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAPs) at Austin Executive Airport, Austin, TX. The...
Two distinct crystallization processes in supercooled liquid
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tane, Masakazu, E-mail: mtane@sanken.osaka-u.ac.jp; Kimizuka, Hajime; Ichitsubo, Tetsu
2016-05-21
Using molecular dynamics simulations we show that two distinct crystallization processes, depending on the temperature at which crystallization occurs, appear in a supercooled liquid. As a model for glass-forming materials, an Al{sub 2}O{sub 3} model system, in which both the glass transition and crystallization from the supercooled liquid can be well reproduced, is employed. Simulations in the framework of an isothermal-isobaric ensemble indicate that the calculated time-temperature-transformation curve for the crystallization to γ(defect spinel)-Al{sub 2}O{sub 3} exhibited a typical nose shape, as experimentally observed in various glass materials. During annealing above the nose temperature, the structure of the supercooled liquidmore » does not change before the crystallization, because of the high atomic mobility (material transport). Thus, the crystallization is governed by the abrupt crystal nucleation, which results in the formation of a stable crystal structure. In contrast, during annealing below the nose temperature, the structure of the supercooled liquid gradually changes before the crystallization, and the formed crystal structure is less stable than that formed above the nose temperature, because of the restricted material transport.« less
NASA Astrophysics Data System (ADS)
Guan, Yinghui
2017-04-01
The variability of surface air temperature and precipitation extremes has been the focus of attention during the past several decades, and may exert a great influence on the global hydrologic cycle and energy balance through thermal forcing. Using daily minimum (TN), maximum temperature (TX) and precipitation from 143 meteorological stations in the Yangtze River Basin (YRB), a suite of extreme climate indices recommended by the Expert Team on Climate Change Detection and Indices, which has rarely been applied in this region, were computed and analyzed during 1960-2012. The results show widespread significant changes in all temperature indices associated with warming in the YRB during 1960-2012. On the whole, cold-related indices, i.e., cold nights, cold days, frost days, icing days and cold spell duration index significantly decreased by -3.45, -1.03, -3.04, -0.42 and -1.6 days/decade, respectively. In contrast, warm-related indices such as warm nights, warm days, summer days, tropical nights and warm spell duration index significantly increased by 2.95, 1.71, 2.16, 1.05 and 0.73 days/decade. Minimum TN, maximum TN, minimum TX and maximum TX increased significantly by 0.42, 0.18, 0.19 and 0.14 °C/decade. Because of a faster increase in minimum temperature than maximum temperature, the diurnal temperature range (DTR) exhibited a significant decreasing trend of -0.09 °C/decade for the whole YRB during 1960-2012. Geographically, stations in the eastern Tibet Plateau and northeastern YRB showed stronger trends in almost all temperature indices. Time series analysis indicated that the YRB was dominated by a general cooling trend before the mid-1980s, but a warming trend afterwards. For precipitation, simple daily intensity index, very wet day precipitation, extremely wet day precipitation, extremely heavy precipitation days, maximum 1-day precipitation, maximum 5-day precipitation and maximum consecutive dry days all increased significantly during 1960-2012. In contrast, ≥ 10 mm precipitation days and maximum consecutive wet days decreased significantly, implying that the precipitation processes in YRB were dominated by precipitation events with shorter durations. Geographically, a wetting tendency was observed in the eastern Tibet Plateau and the middle and lower YRB, while the other regions experienced precipitation deficits. The increasing precipitation was mainly due to the intensification of extreme precipitation events and the decreasing precipitation may be attributed to the decrease of ≥ 10 mm precipitation days or moderate precipitation events. In addition, the regional trends were of greater magnitudes in the middle and lower YRB, indicating more frequent extreme precipitation events in these sub-regions.
Temperature-insensitive phase-matched optical harmonic conversion crystal
Barker, Charles E.; Eimerl, David; Velsko, Stephan P.; Roberts, David
1993-01-01
Temperature-insensitive, phase-matched harmomic frequency conversion of laser light at a preferred wavelength of 1.064 microns can be achieved by use of a crystal of deuterated l-arginine phosphate. The crystal is cut and oriented so that the laser light propagates inside the crystal along one of several required directions, which correspond to a temperature-insensitive, phase-matching locus. The method of measuring and calculating the temperature-insensitive, phase-matching angles can be extended to other fundamental wavelengths and other crystal compositions.
Temperature-insensitive phase-matched optical harmonic conversion crystal
Barker, C.E.; Eimerl, D.; Velsko, S.P.; Roberts, D.
1993-11-23
Temperature-insensitive, phase-matched harmonic frequency conversion of laser light at a preferred wavelength of 1.064 microns can be achieved by use of a crystal of deuterated l-arginine phosphate. The crystal is cut and oriented so that the laser light propagates inside the crystal along one of several required directions, which correspond to a temperature-insensitive, phase-matching locus. The method of measuring and calculating the temperature-insensitive, phase-matching angles can be extended to other fundamental wavelengths and other crystal compositions. 12 figures.
Temperature distribution of laser crystal in end-pumped DPSSL
NASA Astrophysics Data System (ADS)
Zheng, Yibo; Jia, Liping; Zhang, Lei; Wen, Jihua; Kang, Junjian
2009-11-01
The temperature distribution in different cooling system was studied. A thermal distribution model of laser crystal was established. Based on the calculation, the temperature distribution and deformation of ND:YVO4 crystal in different cooling system were obtained. When the pumping power is 2 W and the radius of pumping beams is 320μm, the temperature distribution and end face distortion of the laser crystal are lowest by using side directly hydrocooling method. The study shows that, the side directly hydrocooling method is a more efficient method to control the crystal temperature distribution and reduce the thermal effect.
Federal Register 2010, 2011, 2012, 2013, 2014
2011-11-14
... 3206-AM50 Prevailing Rate Systems; Redefinition of the Austin, TX and Waco, TX, Appropriated Fund... the Federal Prevailing Rate Advisory Committee to best match the counties proposed for redefinition to... Prevailing Rate Advisory Committee (FPRAC), the national labor-management committee responsible for advising...
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2011-02-22
... Shreveport, LA; Texarkana, TX; Milwaukee, WI; and Southwestern Wisconsin Appropriated Fund Federal Wage... Shreveport, LA; Texarkana, TX; Milwaukee, WI; and Southwestern Wisconsin appropriated fund Federal Wage System (FWS) wage areas. The final rule redefines Upshur County, TX, from the Texarkana wage area to the...
75 FR 13669 - Amendment of Class E Airspace; Dumas, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-03-23
...-1151; Airspace Docket No. 09-ASW-30] Amendment of Class E Airspace; Dumas, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace for Dumas, TX, adding... published in the Federal Register a notice of proposed rulemaking to amend Class E airspace for Dumas, TX...
76 FR 61687 - City of College Station, TX; Notice of Filing
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2011-10-05
... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. TX11-2-000] City of College Station, TX; Notice of Filing Take notice that on September 27, 2011, pursuant to sections 210, 211, and... Commission's (Commission) Regulations, 18CFR 36.1, the City of College Station, TX filed an application...
75 FR 31677 - Amendment of Class E Airspace; Austin, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-04
...-1152; Airspace Docket No. 09-ASW-31] Amendment of Class E Airspace; Austin, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace for the Austin, TX... Procedures (SIAPs) at Austin Executive Airport, Austin, TX. The FAA is taking this action to enhance the...
Chen, Wei; Tuladhar, Anupama; Rolle, Shantelle; Lai, Yanhao; Rodriguez Del Rey, Freddy; Zavala, Cristian E; Liu, Yuan; Rein, Kathleen S
2017-08-15
Karenia brevis, the Florida red tide dinoflagellate produces a suite of neurotoxins known as the brevetoxins. The most abundant of the brevetoxins PbTx-2, was found to inhibit the thioredoxin-thioredoxin reductase system, whereas the PbTx-3 has no effect on this system. On the other hand, PbTx-2 activates the reduction of small disulfides such as 5,5'-dithio-bis-(2-nitrobenzoic acid) by thioredoxin reductase. PbTx-2 has an α, β-unsaturated aldehyde moiety which functions as an efficient electrophile and selenocysteine conjugates are readily formed. PbTx-2 blocks the inhibition of TrxR by the inhibitor curcumin, whereas curcumin blocks PbTx-2 activation of TrxR. It is proposed that the mechanism of inhibition of thioredoxin reduction is via the formation of a Michael adduct between selenocysteine and the α, β-unsaturated aldehyde moiety of PbTx-2. PbTx-2 had no effect on the rates of reactions catalyzed by related enzymes such as glutathione reductase, glutathione peroxidase or glutaredoxin. Copyright © 2017 Elsevier Inc. All rights reserved.
Preemptive living-donor kidney transplantation: clinical course and outcome.
el-Agroudy, Amgad E; Donia, Ahmed F; Bakr, Mohamed A; Foda, Mohamed A; Ghoneim, Mohamed A
2004-05-15
Dialysis is not only associated with morbidity, it is also expensive. In developing countries, preemptive renal transplantation (Tx) may be a cost-effective option, offering an additional benefit to conventional renal Tx. Between March 1976 and March 2001, 1,279 first living-donor Txs were performed in our center. The 82 patients (6.4%) who underwent Tx without prior dialysis were compared with 1,197 patients who had been dialyzed before Tx. The dialysis-dependent group received more blood transfusions (65% vs. 30%) before Tx. Actuarial graft and patient survival at 5 years was comparable in both groups (P =0.2 and P =0.8, respectively). The incidence of acute and chronic rejection was not different between the two groups. Mortality rate was also similar in the two groups. The main cause of death with a functioning graft was cardiovascular in the preemptive Tx group and chronic liver disease and infection in the control group. In the context of a developing country, preemptive Tx offers comparable patient and graft survival to conventional renal Tx and eliminates the complications, inconvenience, and cost of dialysis.
Hepatic retransplantation in New England--a regional experience and survival model.
Powelson, J A; Cosimi, A B; Lewis, W D; Rohrer, R J; Freeman, R B; Vacanti, J P; Jonas, M; Lorber, M I; Marks, W H; Bradley, J
1993-04-01
Hepatic retransplantation (reTx) offers the only alternative to death for patients who have failed primary hepatic transplantation (PTx). Assuming a finite number of donor organs, reTx also denies the chance of survival for some patients awaiting PTx. The impact of reTx on overall survival (i.e., the survival of all candidates for transplantation) must therefore be clarified. Between 1983 and 1991, 651 patients from the New England Organ Bank underwent liver transplantation, and 73 reTx were performed in 71 patients (11% reTx rate). The 1-year actuarial survival for reTx (48%) was significantly less than for PTx (70%, P < 0.05). This survival varied, dependent on the interval of time following PTx in which the reTx was performed (0-3 days, 57% survival; 4-30 days, 24%; 30-365 days, 54%; and > 365 days, 83%). Patients on the regional waiting list had an 18% mortality rate while awaiting transplantation. These results were incorporated into a mathematical model describing survival as a function of reTx rate, assuming a limited supply of donor livers. ReTx improves the 1-year survival rate for patients undergoing PTx but decreases overall survival (survival of all candidates) for liver transplantation. In the current era of persistently insufficient donor numbers, strategies based on minimizing the use of reTx, especially in the case of patients in whom chances of success are minimal, will result in the best overall rate of patient survival.
Direct flow crystal growth system
Montgomery, Kenneth E.; Milanovich, Fred P.
1992-01-01
A crystal is grown in a constantly filtered solution which is flowed directly into the growing face of a crystal. In a continuous flow system, solution at its saturation temperature is removed from a crystal growth tank, heated above its saturation temperature, filtered, cooled back to its saturation temperature, and returned to the tank.
Nucleated Poly(L-lactic acid) with N, N‧-oxalyl bis(benzoic acid) dihydrazide
NASA Astrophysics Data System (ADS)
Tian, Liang-Liang; Cai, Yan-Hua
2018-04-01
One of the major challenges in the field of Poly(L-lactic acid) (PLLA) is the enhancement of crystallization. In the present work, the evaluation of the influence of N, N‧-oxalyl bis(benzoic acid) dihydrazide (TBOD), as a novel organic nucleating agent, on the non-isothermal crystallization, melting behavior, and thermal stability of PLLA was performed using differential scanning calorimeter and thermogravimetric analysis. Non-isothermal crystallization measurement revealed that TBOD had an excellent accelerating effect for the crystallization of PLLA in cooling, and upon the addition of 3 wt% TBOD, PLLA exhibited the highest onset crystallization temperature and the crystallization peak temperature, as well as the largest non-isothermal crystallization enthalpy. In particular, when the TBOD concentration was 1 wt% ∼ 3 wt%, the onset crystallization temperatures were higher than the theoretical ceiling temperature of crystallization, thoroughly demonstrating the powerful crystallization promoting ability of TBOD. Additionally, the non-isothermal crystallization behavior of PLLA/TBOD depended on the TBOD concentration, cooling rate as well as the final melting temperature. The melting behavior of PLLA/TBOD after non-isothermal crystallization further confirmed the effect of TBOD on the crystallization process and crystal structure of PLLA, and the appearance of the double melting peaks during melting stages was attribute to the melting-recrystallization. For melting behavior after isothermal crystallization, the crystallization temperature and crystallization time significantly affected the melting behavior of PLLA/TBOD. The addition of TBOD could not change the thermal decomposition profile of the PLLA, but the thermal stability did not regularly decrease with increasing of TBOD concentration, indicating that there might exist intermolecular interaction between PLLA and TBOD.
Thermal diffusion of the lunar magma ocean and the formation of the lunar crust
NASA Astrophysics Data System (ADS)
Zhu, D.; Wang, S.
2010-12-01
The magma ocean hypothesis is consistent with several lines of evidence including planet formation, core-mantle differentiation and geochemical observations, and it is proved as an inevitable stage in the early evolution of planets. The magma ocean is assumed to be homogeneous in previous models during solidification or crystallization[1]. Based on the recent advance and our new data in experimental igneous petrology[2], we question this assumption and propose that an gabbrotic melt, from which the anorthositic lunar crust crystallized, can be produced by thermal diffusion, rather than by magma fractionation. This novel model can provide explanations for the absence of the advection in lunar magma ocean[3] and the old age of the anorthositic lunar crust[4-5]. 1. Solomatov, V., Magma Oceans and Primordial Mantle Differentiation, in Treatise on Geophysics, S. Gerald, Editor. 2007, Elsevier: Amsterdam. p. 91-119. 2. Huang, F., et al., Chemical and isotopic fractionation of wet andesite in a temperature gradient: Experiments and models suggesting a new mechanism of magma differentiation. Geochimica Et Cosmochimica Acta, 2009. 73(3): p. 729-749. 3. Turcotte, D.L. and L.H. Kellogg, Implications of isotope data for the origin of the Moon, in Origin of the Moon, W.K. Hartmann, R.J. Phillips, and G.J. Taylor, Editors. 1986, Lunar and Planet. Inst.: Houston, TX. p. 311-329. 4. Alibert, C., M.D. Norman, and M.T. McCulloch, An ancient Sm-Nd age for a ferroan noritic anorthosite clast from lunar breccia 67016. Geochimica Et Cosmochimica Acta, 1994. 58(13): p. 2921-2926. 5. Touboul, M., et al., Tungsten isotopes in ferroan anorthosites: Implications for the age of the Moon and lifetime of its magma ocean. Icarus, 2009. 199(2): p. 245-249.
Temperature dependence of single-crystal elastic constants of flux-grown alpha-GaPO(4).
Armand, P; Beaurain, M; Rufflé, B; Menaert, B; Papet, P
2009-06-01
The lattice parameter change with respect to temperature (T) has been measured using high-temperature powder X-ray diffraction techniques for high-temperature flux-grown GaPO(4) single crystals with the alpha-quartz structure. The lattice and the volume linear thermal expansion coefficients in the temperature range 303-1173 K were computed from the X-ray data. The percentage linear thermal expansions along the a and c axes at 1173 K are 1.5 and 0.51, respectively. The temperature dependence of the mass density rho of flux-grown GaPO(4) single crystals was evaluated using the volume thermal expansion coefficient alpha(V)(T) = 3.291 x 10(-5) - 2.786 x 10(-8) [T] + 4.598 x 10(-11)[T](2). Single-crystal high-resolution Brillouin spectroscopy measurements have been carried out at ambient pressure from 303 to 1123 K to determine the elastic constants C(IJ) of high-temperature flux-grown GaPO(4) material. The single-crystal elastic moduli were calculated using the sound velocities via the measured Brillouin frequency shifts Deltanu(B). These are, to our knowledge, the highest temperatures at which single-crystal elastic constants of alpha-GaPO(4) have been measured. Most of the room-temperature elastic constant values measured on flux-grown GaPO(4) material are higher than the ones found for hydrothermally grown GaPO(4) single crystals. The fourth-order temperature coefficients of both the Brillouin frequency shifts T(nuB)((n)) and the single-crystal elastic moduli T(C(IJ))((n)) were obtained. The first-order temperature coefficients of the C(IJ) are in excellent agreement with previous reports on low-temperature hydrothermally grown alpha-GaPO(4) single crystals, while small discrepancies in the higher-order temperature coefficients are observed. This is explained in terms of the OH content in the GaPO(4) network, which is an important parameter in the crystal thermal behavior.
Brewer, Michael J; Gordy, John W; Kerns, David L; Woolley, James B; Rooney, William L; Bowling, Robert D
2017-10-01
In response to the 2013 outbreak of sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), on sorghum, Sorghum bicolor (L.), in North America, experiments were conducted at three southern U.S. grain sorghum production locations (Corpus Christi, TX; Winnsboro, LA; Rosenberg, TX). The objectives were to authenticate yield decline on susceptible hybrids (2014 and 2015) and to measure aphid population growth and natural enemy prevalence on susceptible and resistant hybrids with similar genetic background (2014). Yield decline on susceptible hybrids (Tx 2752/Tx430 and DKS53-67) was more substantial when aphid population growth accelerated quickly and peaked above 300 aphids per leaf (50 to nearly 100% yield decline). Location and year variation in maximum aphid density and cumulative aphid-days was high, with doubling time values on the susceptible hybrids ranging between 3.9 and 7.9 d. On resistant Tx2752/Tx2783, leaf injury and yield decline were not seen or less severe than on its paired susceptible Tx2752/Tx430. Aphids declined on Tx2752/Tx2783 after initial colony establishment (Corpus Christi) or took about 60% longer to double in population size when compared with Tx2572/Tx430 (Winnsboro). The predominant natural enemy taxa were aphelinid mummies (Hymenoptera: Aphelinidae), ladybird beetles (Coleoptera: Coccinellidae), and sryphid flies (Diptera: Syrphidae), and they were more prevalent during flowering than prior to flowering. They were generally responsive to changes in aphid density of both susceptible and resistant hybrids, but variability points to need for further study. In future research, full season observations should continue as well as more detailed study of potential compatibility of sorghum resistance and biological control. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Miyake, Kotaro, E-mail: hif.panc@gmail.com; Nishioka, Masanori; Imura, Satoru
Tumor hypoxia has been considered to be a potential therapeutic target, because hypoxia is a common feature of solid tumors and is associated with their malignant phenotype. In the present study, we investigated the antitumor effect of a novel hypoxic cytotoxin, 3-[2-hydroxyethyl(methyl)amino]-2-quinoxalinecarbonitrile 1,4-dioxide (TX-2098) in inhibiting the expression of hypoxia inducible factor-1{alpha} (HIF-1{alpha}), and consequently vascular endothelial cell growth factor (VEGF) expression in pancreatic cancer. The antitumor effects of TX-2098 under hypoxia were tested against various human pancreatic cancer cell lines using WST-8 assay. VEGF protein induced pancreatic cancer was determined on cell-free supernatant by ELISA. Moreover, nude mice bearingmore » subcutaneously (s.c.) or orthotopically implanted human SUIT-2 were treated with TX-2098. Tumor volume, survival and expression of HIF-1 and associated molecules were evaluated in treatment versus control groups. In vitro, TX-2098 inhibited the proliferation of various pancreatic cancer cell lines. In s.c model, tumors from nude mice injected with pancreatic cancer cells and treated with TX-2098 showed significant reductions in volume (P < 0.01 versus control). Quantitative real-time reverse transcription-PCR analysis revealed that TX-2098 significantly inhibited mRNA expression of the HIF-1 associated molecules, VEGF, glucose transporter 1 and Aldolase A (P < 0.01 versus control). These treatments also prolong the survival in orthotopic models. These results suggest that the effect of TX-2098 in pancreatic cancer might be correlated with the expression of VEGF and HIF-1 targeted molecules. -- Highlights: Black-Right-Pointing-Pointer We designed and synthesized novel hypoxic cytoxin, TX-2098. Black-Right-Pointing-Pointer TX-2098 inhibited the proliferation of human pancreatic cancer cells than TPZ. Black-Right-Pointing-Pointer TX-2098 reduced VEGF protein level than TPZ. Black-Right-Pointing-Pointer TX-2098 inhibited mRNA expression of VEGF, GLUT1 and Aldolase A, not HIF-1{alpha}. Black-Right-Pointing-Pointer TX-2098 improved the survival in orthotopic SUIT-2 xenograft model.« less
Infrared study of OH(-) defects in KTiOPO4 crystals
NASA Astrophysics Data System (ADS)
Morris, P. A.; Crawford, M. K.; Jones, B.
1992-12-01
Variations in the concentrations and distributions of the OH(-) defects present in flux and hydrothermal KTiOPO4 (KTP) crystals, measured by infrared spectroscopy of single crystals, are attributed to differences in the growth environments and other nonhydrogenic defects present in the crystals. The concentrations of OH(-) have been estimated from the infrared data to be approximately 400 ppma (parts per million atomic) (3.0 x 10 exp 19/cu cm) in the flux crystals, 1100-1500 ppma (0.74-1.1 x 10 exp 20/cu cm) in the high-temperature hydrothermal and 600 ppma (4.3 x 10 exp 19/cu cm) in the low-temperature hydrothermal crystals. A 3566/cm peak and a 3575/cm band are observed in all crystals. The integrated intensity of the OH(-) absorption band at 3566/cm increases at the expense of the 3575/cm band at higher temperatures in the high-temperature hydrothermal crystals. Several OH(-) peaks (3490, 3455, 3428, 3420, and 3333/cm), which have strongly temperature-dependent linewidths, are present in the hydrothermally grown KTP crystals. The temperature dependencies of their peak frequencies and widths are consistent with the presence of mobile protons in the lattice. The protons located in the 3490 and 3428/cm sites are believed to contribute to the ionic conductivity of the high-conductivity high-temperature hydrothermal crystals.
Albasan, Hasan; Lulich, Jody P; Osborne, Carl A; Lekcharoensuk, Chalermpol; Ulrich, Lisa K; Carpenter, Kathleen A
2003-01-15
To determine effects of storage temperature and time on pH and specific gravity of and number and size of crystals in urine samples from dogs and cats. Randomized complete block design. 31 dogs and 8 cats. Aliquots of each urine sample were analyzed within 60 minutes of collection or after storage at room or refrigeration temperatures (20 vs 6 degrees C [68 vs 43 degrees F]) for 6 or 24 hours. Crystals formed in samples from 11 of 39 (28%) animals. Calcium oxalate (CaOx) crystals formed in vitro in samples from 1 cat and 8 dogs. Magnesium ammonium phosphate (MAP) crystals formed in vitro in samples from 2 dogs. Compared with aliquots stored at room temperature, refrigeration increased the number and size of crystals that formed in vitro; however, the increase in number and size of MAP crystals in stored urine samples was not significant. Increased storage time and decreased storage temperature were associated with a significant increase in number of CaOx crystals formed. Greater numbers of crystals formed in urine aliquots stored for 24 hours than in aliquots stored for 6 hours. Storage time and temperature did not have a significant effect on pH or specific gravity. Urine samples should be analyzed within 60 minutes of collection to minimize temperature- and time-dependent effects on in vitro crystal formation. Presence of crystals observed in stored samples should be validated by reevaluation of fresh urine.
75 FR 6319 - Proposed Amendment of Low Altitude Area Navigation Route T-254; Houston, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-02-09
... Amendment of Low Altitude Area Navigation Route T-254; Houston, TX AGENCY: Federal Aviation Administration... altitude Area Navigation (RNAV) route T-254 in the Houston, TX, terminal area by eliminating the segment..., TX, VORTAC. This action would eliminate a portion of T-254 that is no longer needed; thus, enhance...
76 FR 53352 - Proposed Amendment of Class E Airspace; Alice, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-08-26
... procedures at Old Hoppe Place Airport, Agua Dulce, TX, has made this action necessary for the safety and..., area. Controlled airspace extending upward from 700 feet above the surface is being removed at Old... extending upward from 700 feet or more above the surface of the earth. * * * * * ASW TX E5 Alice, TX...
75 FR 64972 - Proposed Revocation of Class E Airspace; Lone Star, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-10-21
...-0772; Airspace Docket No. 10-ASW-10] Proposed Revocation of Class E Airspace; Lone Star, TX AGENCY... action proposes to remove Class E airspace at Lone Star, TX. Abandonment of the former Lone Star Steel... need for controlled airspace in the Lone Star, TX, area. The FAA is taking this action to ensure the...
76 FR 5303 - Proposed Amendment of Class E Airspace; Carrizo Springs, Glass Ranch Airport, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-01-31
...-0877; Airspace Docket No. 10-ASW-13] Proposed Amendment of Class E Airspace; Carrizo Springs, Glass... rulemaking (NPRM). SUMMARY: This action proposes to amend Class E airspace for the Carrizo Springs, Glass.... * * * * * ASW TX E5 Carrizo Springs, Glass Ranch Airport, TX [Amended] Carrizo Springs, Glass Ranch Airport, TX...
75 FR 17851 - Amendment of Class E Airspace; Dallas-Fort Worth, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-04-08
...-0926; Airspace Docket No. 09-ASW-26] Amendment of Class E Airspace; Dallas-Fort Worth, TX AGENCY... airspace in the Dallas-Fort Worth, TX area. Additional controlled airspace is necessary to accommodate new... proposed rulemaking to amend Class E airspace for the Dallas- Fort Worth, TX area (74 FR 57617) Docket No...
76 FR 28888 - Revocation of Class E Airspace; Gruver Cluck Ranch Airport, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-05-19
...-0272; Airspace Docket No. 11-ASW-3] Revocation of Class E Airspace; Gruver Cluck Ranch Airport, TX... Class E airspace at Gruver, Cluck Ranch Airport, TX. The airport has been abandoned, thereby eliminating the need for controlled airspace in the Gruver, Cluck Ranch Airport, TX, area. The FAA is taking this...
Human metabolites of brevetoxin PbTx-2: Identification and confirmation of structure
Guo, Fujiang; An, Tianying; Rein, Kathleen S.
2010-01-01
Four metabolites were identified upon incubation of brevetoxin (PbTx-2) with human liver microsomes. Chemical transformation of PbTx-2 confirmed the structures of three known metabolites BTX-B5, PbTx-9 and 41, 43-dihydro-BTX-B5 and a previously unknown metabolite, 41, 43-dihydro-PbTx-2. These metabolites were also observed upon incubation of PbTx-2 with nine human recombinant cytochrome P450s (1A1, 1A2, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4 and 3A5). Cytochrome P450 3A4 produced oxidized metabolites while other CYPs generated the reduced products. PMID:20600229
High Resolution Switching Mode Inductance-to-Frequency Converter with Temperature Compensationti
Matko, Vojko; Milanović, Miro
2014-01-01
This article proposes a novel method for the temperature-compensated inductance-to-frequency converter with a single quartz crystal oscillating in the switching oscillating circuit to achieve better temperature stability of the converter. The novelty of this method lies in the switching-mode converter, the use of additionally connected impedances in parallel to the shunt capacitances of the quartz crystal, and two inductances in series to the quartz crystal. This brings a considerable reduction of the temperature influence of AT-cut crystal frequency change in the temperature range between 10 and 40 °C. The oscillator switching method and the switching impedances connected to the quartz crystal do not only compensate for the crystal's natural temperature characteristics but also any other influences on the crystal such as ageing as well as from other oscillating circuit elements. In addition, the method also improves frequency sensitivity in inductance measurements. The experimental results show that through high temperature compensation improvement of the quartz crystal characteristics, this switching method theoretically enables a 2 pH resolution. It converts inductance to frequency in the range of 85–100 μH to 2–560 kHz. PMID:25325334
NASA Astrophysics Data System (ADS)
Wang, Zhong-Jie; Ni, Wen; Li, Ke-Qing; Huang, Xiao-Yan; Zhu, Li-Ping
2011-08-01
The crystallization process of iron-rich glass-ceramics prepared from the mixture of nickel slag (NS) and blast furnace slag (BFS) with a small amount of quartz sand was investigated. A modified melting method which was more energy-saving than the traditional methods was used to control the crystallization process. The results show that the iron-rich system has much lower melting temperature, glass transition temperature ( T g), and glass crystallization temperature ( T c), which can result in a further energy-saving process. The results also show that the system has a quick but controllable crystallization process with its peak crystallization temperature at 918°C. The crystallization of augite crystals begins from the edge of the sample and invades into the whole sample. The crystallization process can be completed in a few minutes. A distinct boundary between the crystallized part and the non-crystallized part exists during the process. In the non-crystallized part showing a black colour, some sphere-shaped augite crystals already exist in the glass matrix before samples are heated to T c. In the crystallized part showing a khaki colour, a compact structure is formed by augite crystals.
The Effect of Temperature and Solution pH on the Nucleation of Tetragonal Lysozyme Crystals
NASA Technical Reports Server (NTRS)
Judge, Russell A.; Jacobs, Randolph S.; Frazier, Tyralynn; Snell, Edward H.; Pusey, Marc L.
1999-01-01
Part of the challenge of macromolecular crystal growth for structure determination is obtaining crystals with a volume suitable for x-ray analysis. In this respect an understanding of the effect of solution conditions on macromolecule nucleation rates is advantageous. This study investigated the effects of supersaturation, temperature, and pH on the nucleation rate of tetragonal lysozyme crystals. Batch crystallization plates were prepared at given solution concentrations and incubated at set temperatures over 1 week. The number of crystals per well with their size and axial ratios were recorded and correlated with solution conditions. Crystal numbers were found to increase with increasing supersaturation and temperature. The most significant variable, however, was pH; crystal numbers changed by two orders of magnitude over the pH range 4.0-5.2. Crystal size also varied with solution conditions, with the largest crystals obtained at pH 5.2. Having optimized the crystallization conditions, we prepared a batch of crystals under the same initial conditions, and 50 of these crystals were analyzed by x-ray diffraction techniques. The results indicate that even under the same crystallization conditions, a marked variation in crystal properties exists.
High-resolution whole-brain diffusion MRI at 7T using radiofrequency parallel transmission.
Wu, Xiaoping; Auerbach, Edward J; Vu, An T; Moeller, Steen; Lenglet, Christophe; Schmitter, Sebastian; Van de Moortele, Pierre-François; Yacoub, Essa; Uğurbil, Kâmil
2018-03-30
Investigating the utility of RF parallel transmission (pTx) for Human Connectome Project (HCP)-style whole-brain diffusion MRI (dMRI) data at 7 Tesla (7T). Healthy subjects were scanned in pTx and single-transmit (1Tx) modes. Multiband (MB), single-spoke pTx pulses were designed to image sagittal slices. HCP-style dMRI data (i.e., 1.05-mm resolutions, MB2, b-values = 1000/2000 s/mm 2 , 286 images and 40-min scan) and data with higher accelerations (MB3 and MB4) were acquired with pTx. pTx significantly improved flip-angle detected signal uniformity across the brain, yielding ∼19% increase in temporal SNR (tSNR) averaged over the brain relative to 1Tx. This allowed significantly enhanced estimation of multiple fiber orientations (with ∼21% decrease in dispersion) in HCP-style 7T dMRI datasets. Additionally, pTx pulses achieved substantially lower power deposition, permitting higher accelerations, enabling collection of the same data in 2/3 and 1/2 the scan time or of more data in the same scan time. pTx provides a solution to two major limitations for slice-accelerated high-resolution whole-brain dMRI at 7T; it improves flip-angle uniformity, and enables higher slice acceleration relative to current state-of-the-art. As such, pTx provides significant advantages for rapid acquisition of high-quality, high-resolution truly whole-brain dMRI data. © 2018 International Society for Magnetic Resonance in Medicine.
Dharnidharka, Vikas R; Lamb, Kenneth E; Zheng, Jie; Schechtman, Kenneth B; Meier-Kriesche, Herwig-Ulf
2015-08-01
Improvements across many facets of transplantation have led to better 1-yr outcomes of transplanted organs. In this study, we assessed whether longer-term attrition rates improved in pediatric kidney (KI), liver (LI), heart (HR) and lung (LU) transplant (TX) survival. We analyzed data between 1989 and 2008 from 5747 KI, 7348 LI, 5103 HR, and 715 LU TXs (under 18 yr of age at transplant, first solitary transplant only), from the National Scientific Registry of Transplant Recipients database in the USA. Kaplan-Meier (K-M) or ordinary least square (OLS) estimates were used to calculate median and projected survival half-lives. Attrition rates, defined as percent failing within a given time period, were stratified by year of TX. Median half-lives from 1989 TX year to 2005 TX year have shown a major improvement only in LI TX, remaining unchanged in HR and KI TX, or remaining very low in LU TX. All four organ TX types have shown a dramatic drop in first-year attrition rates from 1989 to 2008. However, longer-term attrition rates (1-3, 3-5, 5-10 yr) have remained largely unchanged for all four organ TX types. Further progress in long-term survival will need targeting end-points beyond first-year rejection and survival rates. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Enhancement of antitumor activity of OK-432 (picibanil) by Triton X-114 phase partitioning.
Hashimoto, Masahito; Takashige, Katsuhiro; Furuyashiki, Maiko; Yoshidome, Keitaro; Sano, Ryoko; Kawamura, Yutaka; Ijichi, Shinji; Morioka, Hirofumi; Koide, Hiroyuki; Oku, Naoto; Moriya, Yoichiro; Kusumoto, Shoich; Suda, Yasuo
2008-01-01
OK-432 (Picibanil), a Streptococcal immunotherapeutic agent, has been used for immunotherapy of various cancers as a biological response modifier (BRM). However, OK-432 contains multiple components consisting of immunotherapeutic ones and contaminants which may weaken the effects or exert side-effects. In this study, we investigated extraction of contaminants from OK-432 using Triton X-114 (TX-114)-water phase partitioning and examined an antitumor effect of the resulting preparation. OK-432 was subjected to TX-114 partitioning to give residual precipitate designated as OK-TX-ppt. OK-TX-ppt exerted no TLR2-mediated activity, but induced interleukin (IL)-6 in human PBMC. OK-TX-ppt also induced tumor necrosis factor (TNF)-alpha, IL-10, IL-12, and interferon (IFN)-gamma in PBMC. Moreover, IFN-gamma-inducing activity of OK-TX-ppt was significantly higher and IL-10 production was lower than that of OK-432. In tumor-bearing mice model, administration of OK-TX-ppt i.p. extended the survival time of Meth-A-bearing mice compared to OK-432. OK-TX-ppt also increased the levels of IL-12 and IFN-gamma in mouse spleen cells in vitro. These results indicated that TX-114 partitioning removed some contaminants, which attenuates the antitumor effect, from OK-432 and increase the immunotherapeutic effects of OK-432.
A Venom-derived Neurotoxin, CsTx-1, from the Spider Cupiennius salei Exhibits Cytolytic Activities*
Kuhn-Nentwig, Lucia; Fedorova, Irina M.; Lüscher, Benjamin P.; Kopp, Lukas S.; Trachsel, Christian; Schaller, Johann; Vu, Xuan Lan; Seebeck, Thomas; Streitberger, Kathrin; Nentwig, Wolfgang; Sigel, Erwin; Magazanik, Lev G.
2012-01-01
CsTx-1, the main neurotoxic acting peptide in the venom of the spider Cupiennius salei, is composed of 74 amino acid residues, exhibits an inhibitory cysteine knot motif, and is further characterized by its highly cationic charged C terminus. Venom gland cDNA library analysis predicted a prepropeptide structure for CsTx-1 precursor. In the presence of trifluoroethanol, CsTx-1 and the long C-terminal part alone (CT1-long; Gly-45–Lys-74) exhibit an α-helical structure, as determined by CD measurements. CsTx-1 and CT1-long are insecticidal toward Drosophila flies and destroys Escherichia coli SBS 363 cells. CsTx-1 causes a stable and irreversible depolarization of insect larvae muscle cells and frog neuromuscular preparations, which seem to be receptor-independent. Furthermore, this membranolytic activity could be measured for Xenopus oocytes, in which CsTx-1 and CT1-long increase ion permeability non-specifically. These results support our assumption that the membranolytic activities of CsTx-1 are caused by its C-terminal tail, CT1-long. Together, CsTx-1 exhibits two different functions; as a neurotoxin it inhibits L-type Ca2+ channels, and as a membranolytic peptide it destroys a variety of prokaryotic and eukaryotic cell membranes. Such a dualism is discussed as an important new mechanism for the evolution of spider venomous peptides. PMID:22613721
Orientation and Temperature Dependence of Work-Hardening Rate in Cd Single Crystals
NASA Astrophysics Data System (ADS)
Uçar, N.
1997-03-01
The orientation and temperature dependence of the work-hardening rate (WHR) has been investigated in tension in the temperature range from room temperature to 500 K in Cd single crystals. The WHR was found to decrease rapidly with increasing temperature. For 21-1-3 orientated crystals, the WHR increases firstly with increasing temperature until it passes a maximum at about 350 K.
DKDP crystal growth controlled by cooling rate
NASA Astrophysics Data System (ADS)
Xie, Xiaoyi; Qi, Hongji; Shao, Jianda
2017-08-01
The performance of deuterated potassium dihydrogen phosphate (DKDP) crystal directly affects beam quality, energy and conversion efficiency in the Inertial Confinement Fusion(ICF)facility, which is related with the initial saturation temperature of solution and the real-time supersaturation during the crystal growth. However, traditional method to measure the saturation temperature is neither efficient nor accurate enough. Besides, the supersaturation is often controlled by experience, which yields the higher error and leads to the instability during the crystal growth. In this paper, DKDP solution with 78% deuteration concentration is crystallized in different temperatures. We study the relation between solubility and temperature of DKDP and fit a theoretical curve with a parabola model. With the model, the measurement of saturation temperature is simplified and the control precision of the cooling rate is improved during the crystal growth, which is beneficial for optimizing the crystal growth process.
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2012-01-09
... navigational facilities, adding new obstacles, or changing air traffic requirements. These changes are designed..., VOR RWY 26L, Amdt 32 Houston, TX, Sugar Land Rgnl, ILS OR LOC RWY 35, Amdt 4 Houston, TX, Sugar Land Rgnl, RNAV (GPS) RWY 35, Amdt 2 Houston, TX, Sugar Land Rgnl, VOR/DME-A, Amdt 2 Marshall, TX, Harrison...
Registration of 'TAM 113' wheat
USDA-ARS?s Scientific Manuscript database
‘TAM 113’ (Reg. No. CV-1081, PI 666125), a hard red winter wheat (Triticum aestivum L.) cultivar with experimental designation TX02A0252, was developed and released by Texas AgriLife Research in 2010. TAM 113 is an F5–derived line from the cross TX90V6313/TX94V3724 made at Vernon, TX in 1995. Both T...
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2013-06-03
...-0136; Airspace Docket No. 13-ASW-4] Proposed Amendment of Class D Airspace; Waco, TX, and Establishment of Class D Airspace; Waco, TSTC-Waco Airport, TX AGENCY: Federal Aviation Administration (FAA), DOT... Waco, TX, by separating the Class D airspace at Waco Regional Airport from the Class D airspace at TSTC...
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2013-08-08
...-0136; Airspace Docket No. 13-ASW-4] Amendment of Class D Airspace; Waco, TX, and Establishment of Class D Airspace; Waco, TSTC-Waco Airport, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class D airspace at Waco, TX, by separating the Class D airspace...
USDA-ARS?s Scientific Manuscript database
The sorghum (Sorghum bicolor L. Moench) germplasm lines Tx3408 and Tx3409 were developed and released from Texas A&M AgriLife Research and the USDA-ARS in 2015. Both of these lines were developed from intentional crosses using the pedigree method of plant breeding. The breeding crosses for these l...
77 FR 47816 - Foreign-Trade Zone 12-McAllen, TX Application for Subzone TST NA TRIM, LLC Hidalgo, TX
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2012-08-10
... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [S-90-2012] Foreign-Trade Zone 12--McAllen, TX Application for Subzone TST NA TRIM, LLC Hidalgo, TX An application has been submitted to the Foreign-Trade...-purpose subzone status for the facility of TST NA TRIM, LLC, located in Hidalgo, Texas. The application...
NASA Astrophysics Data System (ADS)
Deshmukh, A. A.; Khond, A. A.; Palikundwar, U. A.
2018-05-01
In the present manuscript, influence of compositions on thermal stability (ΔTx) and thermodynamic parameter PHSS of Ca-Mg-Cu bulk metallic glasses (BMGs) is evaluated. The statistical approach of regression analysis is adopted to investigate the compositional variation with ΔTx and PHSS. It is found that calcium (Ca) and copper (Cu) content has goodlinear relationship with ΔTx and PHSS. It is observed that with increase in Ca content, ΔTx and PHSS decreases. On the other hand, increase in Cu content, both ΔTx and PHSS increases. Correlation fit of magnesium (Mg) content with both ΔTx and PHSS is very poor. A graph is also plotted to understand the relationship between ΔTx and PHSS. Result of the relationship between ΔTx and PHSS reveals that the alloy composition having more negative value of PHSS will have more stability. Therefore, compositions with more negative value of PHSS will lead to ease of BMGs formation in Ca-Mg-Cu alloy system and hence more stable it will be. It is expected that these results will be supportive in identifying the compositions having these elements for making BMGs.
Crystallization of copper metaphosphate glass
NASA Technical Reports Server (NTRS)
Bae, Byeong-Soo; Weinberg, Michael C.
1993-01-01
The effect of the valence state of copper in copper metaphosphate glass on the crystallization behavior and glass transition temperature has been investigated. The crystallization of copper metaphosphate is initiated from the surface and its main crystalline phase is copper metaphosphate (Cu(PO)3),independent of the (Cu sup 2+)/(Cu(total)). However, the crystal morphology, the relative crystallization rates, and their temperature dependences are affected by the (Cu sup 2+)/(Cu (total)) ratio in the glass. On the other hand, the totally oxidized glass crystallizes from all over the surface. The relative crystallization rate of the reduced glass to the totally oxidized glass is large at low temperature, but small at high temperature. The glass transition temperature of the glass increases as the (Cu sup 2+)/(Cu(total)) ratio is raised. It is also found that the atmosphere used during heat treatment does not influence the crystallization of the reduced glass, except for the formation of a very thin CuO surface layer when heated in air.
Apparatus for growing HgI.sub.2 crystals
Schieber, Michael M.; Beinglass, Israel; Dishon, Giora
1978-01-01
A method and horizontal furnace for vapor phase growth of HgI.sub.2 crystals which utilizes controlled axial and radial airflow to maintain the desired temperature gradients. The ampoule containing the source material is rotated while axial and radial air tubes are moved in opposite directions during crystal growth to maintain a desired distance and associated temperature gradient with respect to the growing crystal, whereby the crystal interface can advance in all directions, i.e., radial and axial according to the crystallographic structure of the crystal. Crystals grown by this method are particularly applicable for use as room-temperature nuclear radiation detectors.
Flow-induced crystallization in isotactic polypropylene
NASA Astrophysics Data System (ADS)
Hamad, Fawzi Ghassan
Brief intervals of strong flow stretch chains in a semicrystalline polymer melt, which results in an increase in the nuclei number density and a transformation of the crystal structure. This flow-induced crystallization (FIC) phenomenon is explored in this study using highly isotactic polypropylene (iPP) samples. Using one synthesized and five commercial linear isotactic polypropylene samples, we investigate the FIC behavior by imposing shear onto these samples in a rotational rheometer. Equipped with a good temperature control and flexible shear protocol, we apply different temperature and flow conditions. The magnitude of the FIC effect varies with basic processing parameters (shear rate, specific work, crystallization temperature, and shearing temperature) and material properties (totalistic, molecular weight distribution, and particle concentration in the polymer). The scope of this study is to systematically investigate the influences of these parameters on FIC. The FIC effects that are investigated in this dissertation are: crystallization kinetics, persistence time of flow-induced nuclei, and crystal morphology. The crystallization time was measured in the rheometer by monitoring the onset of crystallization after quenching samples sheared above Tm. These samples were subsequently used to study their flow-induced nuclei persistence time and crystal morphology. The lifetime of flow-induced nuclei was determined by measuring the time required to return from FIC back to quiescent crystallization using a differential scanning calorimeter. The crystal morphology was imaged using polarized optical microscopy and atomic force microscopy. We investigated the influence of specific work on the three FIC characteristics, and found three regimes that are separated by the critical work ( Wc) and the saturation work (Wsat) thresholds. Below the critical work threshold, the morphology is composed of mostly spherulite crystals, which keep a constant volume, and a small fraction of rice grain (anisotropic) crystals. The number of rice grain crystals increases with specific work, speeding up the crystallization time of the semicrystalline polymer. At critical work, spherulite formation stops, and the morphology consists only of rice grain structures. This morphology allows the sample to crystallize at higher temperatures when cooling at 5 C/min, with the sheared sample crystallizing at 129C compared to the unsheared sample at 113C. . Shearing isotactic polypropylene at higher temperatures reduced the FIC effect after subsequent quenching. Generally speaking, shearing at higher temperatures results in slower crystallization, but surprisingly, the influence of temperature is rather weak. Flow-induced crystallization persists even when shear is applied well above the equilibrium melting temperature (187C), finally weakening above the Hoffman-Weeks temperature (210C). This is likely due to the long lifetime of flow- induced precursors (crystallize to form rice grains), which remain stable at temperatures below 210C and only start to disappear slowly in prolonged annealing at temperatures above 210C (diminishing the FIC effect). Tacticity was found to govern the maximum nuclei number density in sheared samples; samples with lower isotactic content show a stronger FIC effect. Similarly, it was found that the concentration of particulates (mainly catalyst residue) are crucially important to FIC, samples with lower amounts of particles lowering the FIC nuclei number density. Data shows that the rate at which the crystallization time changes correlates with the prominence of the high molecular weight tail. A sample with a higher molecular weight tail in its distribution exhibits a faster change in crystallization time as a function of specific work. Similarly, increasing the molecular weight of the added component in a blend induces a larger change in the FIC behavior. (Abstract shortened by ProQuest.).
Determinants of Treatment Abandonment in Childhood Cancer: Results from a Global Survey.
Friedrich, Paola; Lam, Catherine G; Kaur, Geetinder; Itriago, Elena; Ribeiro, Raul C; Arora, Ramandeep S
2016-01-01
Understanding and addressing treatment abandonment (TxA) is crucial for bridging the pediatric cancer survival gap between high-income (HIC) and low-and middle-income countries (LMC). In childhood cancer, TxA is defined as failure to start or complete curative cancer therapy and known to be a complex phenomenon. With rising interest on causes and consequences of TxA in LMC, this study aimed to establish the lay-of-the-land regarding determinants of TxA globally, perform and promote comparative research, and raise awareness on this subject. Physicians (medical oncologists, surgeons, and radiation therapists), nurses, social workers, and psychologists involved in care of children with cancer were approached through an online survey February-May 2012. Queries addressed social, economic, and treatment-related determinants of TxA. Free-text comments were collected. Descriptive and qualitative analyses were performed. Appraisal of overall frequency, burden, and predictors of TxA has been reported separately. 581 responses from 101 countries were obtained (contact rate = 26%, cooperation rate = 70%). Most respondents were physicians (86%), practicing pediatric hematology/oncology (86%) for >10 years (54%). Providers from LMC considered social/economic factors (families' low socioeconomic status, low education, and long travel time), as most influential in increasing risk of TxA. Treatment-related considerations such as preference for complementary and alternative medicine and concerns about treatment adverse effects and toxicity, were perceived to play an important role in both LMC and HIC. Perceived prognosis seemed to mediate the role of other determinants such as diagnosis and treatment phase on TxA risk. For example, high-risk of TxA was most frequently reported when prognosis clearly worsened (i.e. lack of response to therapy, relapse), or conversely when the patient appeared improved (i.e. induction completed, mass removed), as well as before aggressive/mutilating surgery. Provider responses allowed development of an expanded conceptual model of determinants of TxA; one which illustrates established and emerging individual, family, center, and context specific factors to be considered in order to tackle this problem. Emerging factors included vulnerability, family dynamics, perceptions, center capacity, public awareness, and governmental healthcare financing, among others. TxA is a complex and multifactorial phenomenon. With increased recognition of the role of TxA on global pediatric cancer outcomes, factors beyond social/economic status and beliefs have emerged. Our results provide insights regarding the role of established determinants of TxA in different geographical and economic contexts, allow probing of key determinants by deliberating their mechanisms, and allow building an expanded conceptual model of established and emerging determinants TxA.
Nunes, Kenia P; Cordeiro, Marta N; Richardson, Michael; Borges, Marcia N; Diniz, Simone O F; Cardoso, Valbert N; Tostes, Rita; De Lima, Maria Elena; Webb, Robert Clinton; Leite, Romulo
2010-12-01
Priapism is one of several symptoms observed in accidental bites by the spider Phoneutria nigriventer. The venom of this spider is comprised of many toxins, and the majority has been shown to affect excitable ion channels, mainly sodium (Na(+) ) channels. It has been demonstrated that PnTx2-6, a peptide extracted from the venom of P. nigriventer, causes erection in anesthetized rats and mice. We investigated the mechanism by which PnTx2-6 evokes relaxation in rat corpus cavernosum. PnTx2-6 toxin potentiates nitric oxide (NO)-dependent cavernosal relaxation. Rat cavernosal strips were incubated with bretylium (3 × 10(-5) M) and contracted with phenylephrine (PE; 10(-5) M). Relaxation responses were evoked by electrical field stimulation (EFS) or sodium nitroprusside (SNP) before and after 4 minutes of incubation with PnTx2-6 (10(-8) M). The effect of PnTx2-6 on relaxation induced by EFS was also tested in the presence of atropine (10(-6) M), a muscarinic receptor antagonist, N-type Ca(2+) channel blockers (ω-conotoxin GVIA, 10(-6) M) and sildenafil (3 × 10(-8) M). Technetium99m radiolabeled PnTx2-6 subcutaneous injection was administrated in the penis. Whereas relaxation induced by SNP was not affected by PnTx2-6, EFS-induced relaxation was significantly potentiated by this toxin as well as PnTx2-6 plus SNP. This potentiating effect was further increased by sildenafil, not altered by atropine, however was completely blocked by the N-type Ca(2+) channels. High concentrated levels of radiolabeled PnTx2-6 was specifically found in the cavernosum tissue, suggesting PnTx2-6 is an important toxin responsible for P. nigriventer spider accident-induced priapism. We show that PnTx2-6 slows Na(+) channels inactivation in nitrergic neurons, allowing Ca(2+) influx to facilitate NO/cGMP signalling, which promotes increased NO production. In addition, this relaxation effect is independent of phosphodiesterase enzyme type 5 inhibition. Our data displays PnTx2-6 as possible pharmacological tool to study alternative treatments for erectile dysfunction. © 2010 International Society for Sexual Medicine.
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..., RNAV (GPS) RWY 35, Orig Childress, TX, Childress Muni, RNAV (GPS) RWY 36, Amdt 1 Dallas-Fort Worth, TX, Dallas/Fort Worth Intl, CONVERGING ILS RWY 13R, Amdt 7 Dallas-Fort Worth, TX, Dallas/Fort Worth Intl, CONVERGING ILS RWY 17R, Amdt 9 Dallas-Fort Worth, TX, Dallas/Fort Worth Intl, CONVERGING ILS RWY 18L, Amdt 2...
76 FR 9640 - Prevailing Rate Systems: Santa Clara, CA, Tulsa County, OK, and Angelina County, TX
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2011-02-22
... System (FWS) wage area and Angelina County, Texas, as an area of application to the Dallas, TX, NAF FWS... County, Texas, as an area of application to the Dallas, TX, NAF FWS wage area. The Federal Prevailing... area listing for the Oklahoma, OK, and Dallas, TX, NAF wage areas to read as follows: Appendix D to...
78 FR 33263 - Proposed Amendment of Class D and Class E Airspace; San Marcos, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2013-06-04
...] San Marcos Municipal Airport, TX (Lat. 29[deg]53'34'' N., long. 97[deg]51'47'' W.) That airspace... [Amended] San Marcos Municipal Airport, TX (Lat. 29[deg]53[min]34[sec] N., long. 97[deg]51'47'' W.) Lockhart Municipal Airport, TX (Lat. 29[deg]51'01'' N., long. 97[deg]40'21'' W.) That airspace extending...
Effect of shallow angles on compressive strength of biaxial and triaxial laminates.
Jia, Hongli; Yang, Hyun-Ik
2016-01-01
Biaxial (BX) and triaxial (TX) composite laminates with ±45° angled plies have been widely used in wind turbine blades. As the scale of blades increases, BX and TX laminates with shallow-angled plies (i.e. off-axis ply angle <45°) might be utilized for reducing mass and/or improving performance. The compressive properties of shallow-angled BX and TX laminates are critical considering their locations in a wind turbine blade, and therefore in this study, the uniaxial static compression tests were conducted using BX and TX laminates with angled-plies of ±45°, ±35°, and ±25°, for the purpose of evaluation. On the other hand, Mori-Tanaka mean field homogenization method was employed to predict elastic constants of plies in BX and TX laminates involved in tests; linear regression analyses of experimentally measured ply strengths collected from various sources were then performed to estimate strengths of plies in BX and TX laminates; finally, Tsai-Wu, Hashin, and Puck failure criteria were chosen to predict compressive strengths of BX and TX laminates. Comparison between theoretical predictions and test results were carried out to illustrate the effectiveness of each criterion. The compressive strength of BX laminate decreases as ply angle increases, and the trend was successfully predicted by all three failure criteria. For TX laminates, ±35° angled plies rather than ±45° angled plies led to the lowest laminate compressive strength. Hashin and Puck criteria gave good predictions at certain ply angles for TX laminates, but Tsai-Wu criterion was able to capture the unexpected strength variation of TX laminates with ply angle. It was concluded that the transverse tensile stress in 0° plies of TX laminates, which attains its maximum when the off-axis ply angle is 35°, is the dominant factor in failure determination if using Tsai-Wu criterion. This explains the unexpected strength variation of TX laminates with ply angle, and also indicates that proper selection of ply angle is the key to fully utilizing the advantages of shallow-angled laminates.
Souza, M H; Melo-Filho, A A; Rocha, M F; Lyerly, D M; Cunha, F Q; Lima, A A; Ribeiro, R A
1997-01-01
Clostridium difficile (Cd) toxins appear to mediate the inflammatory response in pseudomembranous colitis and/or colitis associated with the use of antibiotics. In contrast to Cd Toxin A (TxA), Cd Toxin B (TxB) has been reported not to promote fluid secretion or morphological damage in rabbits and hamsters and also does not induce neutrophil chemotaxis in vitro. However, TxB is about 1000 times more potent than TxA in stimulating the release of tumour necrosis factor-alpha (TNF-alpha) by cultured monocytes. In the present study, we investigated the ability of TxB to promote neutrophil migration into peritoneal cavities and subcutaneous air-pouches of rats. We also examined the role of resident peritoneal cells in this process as well as the inflammatory mediators involved. TxB caused a significant and dose-dependent neutrophil influx with a maximal response at 0.1 microgram/cavity after 4 hr. Depleting the peritoneal resident cell population by washing the peritoneal cavity or increasing this population by pretreating the animals with thioglycollate blocked and amplified the TxB-induced neutrophil migration, respectively. Pretreating the animals with MK886 (a lipoxygenase inhibitor), NDGA (a dual cyclo- and lipoxygenase inhibitor) or the glucocorticoid, dexamethasone, but not with indomethacin (a cyclo-oxygenase inhibitor), or BN52021 (a platelet-activating factor antagonist), inhibited the neutrophil migration evoked by TxB. Pretreatment with dexamethasone or the administration of anti-TNF-alpha serum into the air-pouches also significantly reduced the TxB-induced neutrophil migration. Supernatants from TxB-stimulated macrophages induced neutrophil migration when injected into the rat peritoneal cavity. This effect was attenuated by the addition of either MK886 or dexamethasone to the macrophage monolayer and by preincubating the supernatants with anti-TNF-alpha serum. TxB also stimulated the release of TNF-alpha by macrophages. Overall, these results suggest that TxB induces an intense neutrophil migration which is mediated by macrophage-derived TNF-alpha and lipoxygenase products. PMID:9227329
Roth, Patricia B; Twiner, Michael J; Wang, Zhihong; Bottein Dechraoui, Marie-Yasmine; Doucette, Gregory J
2007-12-15
Flavobacteriaceae (strain S03) and Cytophaga sp. (strain 41-DBG2) are algicidal bacteria active against the brevetoxin (PbTx)-producing, red tide dinoflagellate, Karenia brevis. Little is known about the fate of PbTx associated with K. brevis cells following attack by such bacteria. The fate and distribution of PbTx in K. brevis cultures exposed to these algicidal strains were thus examined by receptor binding assay and liquid chromatography/mass spectrometry (LC/MS) in three size fractions (>5, 0.22-5, <0.22microm) over a 2-week time course. In control cultures, brevetoxin concentrations in the >5microm particulate size fraction correlated with changes in cell density, whereas significant increases in dissolved (i.e., <0.22microm) toxin were observed in the later stages of culture growth. Exposure of K. brevis to either of the two algicidal bacteria tested caused cell lysis, coinciding with a rapid decline in the >5microm PbTX size fraction and a simultaneous release of dissolved toxin into the growth medium. Upon cell lysis, dissolved brevetoxin accounted for ca. 60% of total toxin and consisted of 51-82% open A-ring derivatives. Open A-ring PbTx-2 and PbTx-3 derivatives bound with lower affinity (approximately 22- and 57-fold, respectively) to voltage-gated sodium channels and were considerably less cytotoxic (86- and 142-fold, respectively) to N2A cells than their individual parent toxins (i.e., PbTx-2 and PbTx-3). These novel findings of changes in PbTx size-fractioned distribution and overall reduction in K. brevis toxicity following attack by algicidal bacteria improve our understanding of potential trophic transfer routes and the fate of PbTx during red tide events. Moreover, this information will be important to consider when evaluating the potential role of algicidal bacteria in harmful algal bloom (HAB) management strategies involving control of bloom populations.
The Effect of Temperature and Solution pH on Tetragonal Lysozyme Nucleation Kinetics
NASA Technical Reports Server (NTRS)
Judge, Russell A.; Jacobs, Randolph S.; Frazier, Tyralynn; Snell, Edward H.; Pusey, Marc L.
1998-01-01
Part of the challenge of macromolecular crystal growth for structure determination is obtaining an appropriate number of crystals with a crystal volume suitable for x-ray analysis. In this respect an understanding of the effect of solution conditions on macromolecule nucleation rates is advantageous. This study investigated the effects of supersaturation, temperature and pH on the nucleation rate of tetragonal lysozyme crystals. Batch crystallization plates were prepared at given solution concentrations and incubated at set temperatures over one week. The number of crystals per well with their size and axial ratios were recorded and correlated with solution conditions, Duplicate experiments indicate the reproducibility of the technique, Crystal numbers were found to increase with increasing supersaturation and temperature. The most significant variable however, was pH, where crystal numbers changed by two orders of magnitude over the pH range 4.0 to 5.2. Crystal size varied also with solution conditions, with the largest crystals being obtained at pH 5.2. Having optimized the crystallization conditions, a batch of crystals were prepared under exactly the same conditions and fifty of these crystals were analyzed by x-ray techniques. The results indicate that even under the same crystallization conditions, a marked variation in crystal properties exists.
Thioredoxin-Interacting Protein Deficiency Protects against Diabetic Nephropathy.
Shah, Anu; Xia, Ling; Masson, Elodie A Y; Gui, Chloe; Momen, Abdul; Shikatani, Eric A; Husain, Mansoor; Quaggin, Susan; John, Rohan; Fantus, I G
2015-12-01
Expression of thioredoxin-interacting protein (TxNIP), an endogenous inhibitor of the thiol oxidoreductase thioredoxin, is augmented by high glucose (HG) and promotes oxidative stress. We previously reported that TxNIP-deficient mesangial cells showed protection from HG-induced reactive oxygen species, mitogen-activated protein kinase phosphorylation, and collagen expression. Here, we investigated the potential role of TxNIP in the pathogenesis of diabetic nephropathy (DN) in vivo. Wild-type (WT) control, TxNIP(-/-), and TxNIP(+/-) mice were rendered equally diabetic with low-dose streptozotocin. In contrast to effects in WT mice, diabetes did not increase albuminuria, proteinuria, serum cystatin C, or serum creatinine levels in TxNIP(-/-) mice. Whereas morphometric studies of kidneys revealed a thickened glomerular basement membrane and effaced podocytes in the diabetic WT mice, these changes were absent in the diabetic TxNIP(-/-) mice. Immunohistochemical analysis revealed significant increases in the levels of glomerular TGF-β1, collagen IV, and fibrosis only in WT diabetic mice. Additionally, only WT diabetic mice showed significant increases in oxidative stress (nitrotyrosine, urinary 8-hydroxy-2-deoxy-guanosine) and inflammation (IL-1β mRNA, F4/80 immunohistochemistry). Expression levels of Nox4-encoded mRNA and protein increased only in the diabetic WT animals. A significant loss of podocytes, assessed by Wilms' tumor 1 and nephrin staining and urinary nephrin concentration, was found in diabetic WT but not TxNIP(-/-) mice. Furthermore, in cultured human podocytes exposed to HG, TxNIP knockdown with siRNA abolished the increased mitochondrial O2 (-) generation and apoptosis. These data indicate that TxNIP has a critical role in the progression of DN and may be a promising therapeutic target. Copyright © 2015 by the American Society of Nephrology.
Karki, Pratap; Webb, Anton; Smith, Keisha; Lee, Kyuwon; Son, Deok-Soo; Aschner, Michael; Lee, Eunsook
2013-01-01
Tamoxifen (TX), a selective estrogen receptor modulator, exerts antagonistic effects on breast tissue and is used to treat breast cancer. Recent evidence also suggests that it may act as an agonist in brain tissue. We reported previously that TX enhanced the expression and function of glutamate transporter 1 (GLT-1) in rat astrocytes, an effect that was mediated by TGF-α. To gain further insight into the mechanisms that mediate TX-induced up-regulation of GLT-1 (EAAT2 in humans), we investigated its effect on GLT-1 at the transcriptional level. TX phosphorylated the cAMP response element-binding protein (CREB) and recruited CREB to the GLT-1 promoter consensus site. The effect of TX on astrocytic GLT-1 was attenuated by the inhibition of PKA, the upstream activator of the CREB pathway. In addition, the effect of TX on GLT-1 promoter activity was abolished by the inhibition of the NF-κB pathway. Furthermore, TX recruited the NF-κB subunits p65 and p50 to the NF-κB binding domain of the GLT-1 promoter. Mutation of NF-κB (triple, −583/-282/-251) or CRE (-308) sites on the GLT-1 promoter led to significant repression of the promoter activity, but neither mutant completely abolished the TX-induced GLT-1 promoter activity. Mutation of both the NF-κB (-583/-282/-251) and CRE (-308) sites led to a complete abrogation of the effect of TX on GLT-1 promoter activity. Taken together, our findings establish that TX regulates GLT-1 via the CREB and NF-κB pathways. PMID:23955341
Kim, Myoung Soo; Kim, Hae Jin; Kim, Soon Il; Ahn, Hyung Joon; Ju, Man Ki; Kim, Hyun Jung; Jeon, Kyung Ock; Kim, Yu Seun
2006-12-27
Serum soluble CD30 (sCD30) levels might be a useful marker of immunologic status in pre transplant (Tx) recipients. We retrospectively correlated preTx sCD30 levels (high versus low) on postTx graft survival, incidence of acute rejection, and graft function using stored preTx serum. Of 254 recipients who underwent kidney Tx, 120 recipients were enrolled under the uniform criteria (living donor, age >25 years, viral hepatitis free, diabetes free). The preTx sCD30 was not significantly associated with differences in graft survival rate during 47.5+/-11.4 months of follow-up (P = 0.5901). High sCD30 (> or =115 U/ml) was associated with a higher incidence of clinically or pathologically defined acute rejection than low sCD30, but the difference was not statistically significant (33.9% vs. 22.4%, P = 0.164). The response rate to antirejection therapy in patients with high sCD30 was inferior to those with low sCD30, but also was not statistically significant (33.3% vs. 7.7%, P = 0.087). However, mean serum creatinine levels in high sCD30 patients at one month, one year, and three years postTx were significantly different from those with low sCD30 (P < 0.05). In multiple regression analysis, acute rejection episodes, donor age, kidney weight/recipient body weight ratio, and preTx sCD30 levels were independent variables affecting the serum creatinine level three years postTx. PreTx sCD30 level has a limited effect on the incidence of acute rejection and response to antirejection treatment, but inversely and independently affects serum creatinine level after living donor kidney transplantation.
NASA Astrophysics Data System (ADS)
Yumoto, Hisami; Hasiguti, Ryukiti R.
1984-07-01
Hexagonal prismatic Cd crystals having {10\\bar{1}0} prismatic planes, or occasionally having {11\\bar{2}0} prismatic planes, were grown as high-temperature-type Cd crystals by the thin layer VLS mechanism at Ts (growth temperature) ≥ Tt (transition temperature range: 250-260°C). Pencil-shaped Cd crystals (low-temperature-type Cd crystals) were grown, having {10\\bar{1}0} and {11\\bar{2}0} prismatic planes and {10\\bar{1}1} pyramidal planes by the mixed-type VLS mechanism at Ts≤Tt. When the growth temperature was decreased below Tt, the shape of the solid-liquid interface changed from rounded to faceted. Three processes for the termination of the mixed-type VLS growth are proposed.
NASA Astrophysics Data System (ADS)
Sun, F. Z.; Zhang, P.; Liang, Y. C.; Lu, L. H.
2014-09-01
In the non-critical phase-matching (NCPM) along the Θ =90° direction, ADP and DKDP crystals which have many advantages, including a large effective nonlinear optical coefficient, a small PM angular sensitivity and non beam walk-off, at the non-critical phase-matching become the competitive candidates in the inertial confinement fusion(ICF) facility, so the reasonable temperature control of crystals has become more and more important .In this paper, the fluid-solid coupling models of ADP crystal and DKDP crystal which both have anisotropic thermal conductivity in the states of vacuum and non-vacuum were established firstly, and then simulated using the fluid analysis software Fluent. The results through the analysis show that the crystal surface temperature distribution is a ring shape, the temperature gradients in the direction of the optical axis both the crystals are 0.02°C and 0.01°C due to the air, the lowest temperature points of the crystals are both at the center of surface, and the temperatures are lower than 0.09°C and 0.05°C compared in the vacuum and non-vacuum environment, then propose two designs for heating apparatus.
Liu, Hao; Skinner, Robert D; Arfaj, Ahmad; Yates, Charlotte; Reese, Nancy B; Williams, Keith; Garcia-Rill, Edgar
2010-10-30
This study investigated whether l-dopa (DOPA), locomotor-like passive exercise (Ex) using a motorized bicycle exercise trainer (MBET), or their combination in adult rats with complete spinal cord transection (Tx) preserves and restores low frequency-dependent depression (FDD) of the H-reflex. Adult Sprague-Dawley rats (n=56) transected at T8-9 had one of five treatments beginning 7 days after transection: Tx (transection only), Tx+Ex, Tx+DOPA, Tx+Ex+DOPA, and control (Ctl, no treatment) groups. After 30 days of treatment, FDD of the H-reflex was tested. Stimulation of the tibial nerve at 0.2, 1, 5, and 10Hz evoked an H-reflex that was recorded from plantar muscles of the hind paw. No significant differences were found at the stimulation rate of 1Hz. However, at 5Hz, FDD of the H-reflex in the Tx+Ex, Tx+DOPA and Ctl groups was significantly different from the Tx group (p<0.01). At 10Hz, all of the treatment groups were significantly different from the Tx group (p<0.01). No significant difference was identified between the Ctl and any of the treatment groups. These results suggest that DOPA significantly preserved and restored FDD after transection as effectively as exercise alone or exercise in combination with DOPA. Thus, there was no additive benefit when DOPA was combined with exercise. Copyright © 2010 Elsevier Inc. All rights reserved.
Cyclooxygenase-2-dependent bronchoconstriction in perfused rat lungs exposed to endotoxin.
Uhlig, S; Nüsing, R; von Bethmann, A; Featherstone, R L; Klein, T; Brasch, F; Müller, K M; Ullrich, V; Wendel, A
1996-05-01
Lipopolysaccharides (LPS), widely used to study the mechanisms of gram-negative sepsis, increase airway resistance by constriction of terminal bronchioles. The role of the cyclooxygenase (COX) isoenzymes and their prostanoid metabolites in this process was studied. Pulmonary resistance, the release of thromboxane (TX) and the expression of COX-2 mRNA were measured in isolated blood-free perfused rat lungs exposed to LPS. LPS induced the release of TX and caused increased airway resistance after about 30 min. Both TX formation and LPS-induced bronchoconstriction were prevented by treatment with the unspecific COX inhibitor acetyl salicylic acid, the specific COX-2 inhibitor CGP-28238, dexamethasone, actinomycin D, or cycloheximide. LPS-induced bronchoconstriction was also inhibited by the TX receptor antagonist BM-13177. The TX-mimetic compound, U-46619, increased airway resistance predominantly by constricting terminal bronchioles. COX-2-specific mRNA in lung tissue was elevated after LPS exposure, and this increase was attenuated by addition of dexamethasone or of actinomycin D. In contrast to LPS, platelet-activating factor (PAF) induced immediate TX release and bronchoconstriction that was prevented by acetyl salicylic acid, but not by CGP-28238. LPS elicits the following biochemical and functional changes in rat lungs: (i) induction of COX-2; (ii) formation of prostaglandins and TX; (iii) activation of the TX receptor on airway smooth muscle cells; (iv) constriction of terminal bronchioles; and (v) increased airway resistance. In contrast to LPS, the PAF-induced TX release is likely to depend on COX-1.
Guimarães, C L S; Andrião-Escarso, S H; Moreira-Dill, L S; Carvalho, B M A; Marchi-Salvador, D P; Santos-Filho, N A; Fernandes, C A H; Fontes, M R M; Giglio, J R; Barraviera, B; Zuliani, J P; Fernandes, C F C; Calderón, L A; Stábeli, R G; Albericio, F; da Silva, S L; Soares, A M
2014-01-01
Crude venom of Bothrops jararacussu and isolated phospholipases A2 (PLA2) of this toxin (BthTX-I and BthTX-II) were chemically modified (alkylation) by p-bromophenacyl bromide (BPB) in order to study antibody production capacity in function of the structure-function relationship of these substances (crude venom and PLA2 native and alkylated). BthTX-II showed enzymatic activity, while BthTX-I did not. Alkylation reduced BthTX-II activity by 50% while this process abolished the catalytic and myotoxic activities of BthTX-I, while reducing its edema-inducing activity by about 50%. Antibody production against the native and alkylated forms of BthTX-I and -II and the cross-reactivity of antibodies to native and alkylated toxins did not show any apparent differences and these observations were reinforced by surface plasmon resonance (SPR) data. Histopathological analysis of mouse gastrocnemius muscle sections after injection of PBS, BthTX-I, BthTX-II, or both myotoxins previously incubated with neutralizing antibody showed inhibition of the toxin-induced myotoxicity. These results reveal that the chemical modification of the phospholipases A2 (PLA2) diminished their toxicity but did not alter their antigenicity. This observation indicates that the modified PLA2 may provide a biotechnological tool to attenuate the toxicity of the crude venom, by improving the production of antibodies and decreasing the local toxic effects of this poisonous substance in animals used to produce antivenom.
NASA Astrophysics Data System (ADS)
Mikhnev, L. V.; Bondarenko, E. A.; Chapura, O. M.; Skomorokhov, A. A.; Kravtsov, A. A.
2018-01-01
The influence of annealing temperature on the transmission spectra of photonic crystals composed of polystyrene and silicon dioxide microspheres was studied. It was found that annealing of photonic crystals based on polystyrene and silica leads to a shift in the photonic band gap to the short-wavelength region. Based on the results of optical studies, the dependences of the structural parameters of the obtained opal-like crystals on annealing temperature were obtained. In the case of polystyrene photonic crystals, the displacement of the photonic band gap is observed in a narrow temperature range above the glass transition temperature. For SiO2 photonic crystals, it was found that the process of microspheres sintering is complex and involves three stages of structural modification.
Effectiveness of Low Temperature Additives for Biodiesel Blends
2012-06-30
Westbrook U.S. Army TARDEC Fuels and Lubricants Research Facility Southwest Research Institute® (SwRI®) San Antonio, TX for U.S. Army TARDEC...INTERIM REPORT TFLRF No. 428 by Steven R. Westbrook U.S. Army TARDEC Fuels and Lubricants Research Facility Southwest Research Institute...Director U.S. Army TARDEC Fuels and Lubricants Research Facility (SwRI®) UNCLASSIFIED UNCLASSIFIED REPORT DOCUMENTATION PAGE Form Approved
Detail view of the underside of a elevon on the ...
Detail view of the underside of a elevon on the port side wing of the Orbiter Discovery. Note the wear and replacement patterns of the High-temperature Reusable Surface Insulation tiles. This image was taken inside of the Orbiter Processing Facility at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX
Effect of a Metal Deactivator Fuel Additive on Fuel Deposition in Fuel Atomizers at High Temperature
1992-08-01
ARMY NATICK RD&E CENTER DEVELOPMENT AND ENGINEERING CTR ATTN: SATNC-U ATUN : SATBE-F I NATICK MA 01760-5020 SATBE-FL 10 SATBE-BT 2 DIRECTOR SATBE-TQ 1...SFT (MR MAKRIS) I WASHINGTON DC 20330 SAALC/LDPE (MR ELLIOT) 1 KELLY AIR FORCE BASE TX 78241 CDR US AIR FORCE WRIGHT AERO LAB CDR ATUN : POSF (MR
NASA Astrophysics Data System (ADS)
Mojahedi, Mahdi; Shekoohinejad, Hamidreza
2018-02-01
In this paper, temperature distribution in the continuous and pulsed end-pumped Nd:YAG rod crystal is determined using nonclassical and classical heat conduction theories. In order to find the temperature distribution in crystal, heat transfer differential equations of crystal with consideration of boundary conditions are derived based on non-Fourier's model and temperature distribution of the crystal is achieved by an analytical method. Then, by transferring non-Fourier differential equations to matrix equations, using finite element method, temperature and stress of every point of crystal are calculated in the time domain. According to the results, a comparison between classical and nonclassical theories is represented to investigate rupture power values. In continuous end pumping with equal input powers, non-Fourier theory predicts greater temperature and stress compared to Fourier theory. It also shows that with an increase in relaxation time, crystal rupture power decreases. Despite of these results, in single rectangular pulsed end-pumping condition, with an equal input power, Fourier theory indicates higher temperature and stress rather than non-Fourier theory. It is also observed that, when the relaxation time increases, maximum amounts of temperature and stress decrease.
Federal Register 2010, 2011, 2012, 2013, 2014
2011-05-26
... Obstacle DP, Orig Houston, TX, William P Hobby, ILS OR LOC RWY 30L, Amdt 6 Houston, TX, William P Hobby, RNAV (GPS) RWY 12R, Amdt 1A Houston, TX, William P Hobby, RNAV (GPS) RWY 30L, Amdt 2 Houston, TX, William P Hobby, VOR/DME RWY 30L, Amdt 18 Moneta, VA, Smith Mountain Lake, RNAV (GPS) RWY 23, Orig...
NASA Astrophysics Data System (ADS)
Vorontsov, N. V.; Popov, A. A.; Margolin, A. L.
2017-12-01
Changes in the supramolecular structure of polymer composites based on isotactic polypropylene (PP) and polyamide 6/66 (PA) are studied depending on the PP : PA ratio. Temperatures and enthalpies of melting and crystallization of both PP and PA and their composites are determined depending on the composition of the mixtures. It was shown that the initial melting point of a composite does not change with increasing PA content in the blends. The crystallization temperature of the mixtures is shown to increase with the addition of PA and becomes much higher than the crystallization temperatures of both PP and PA. The observed effect can be due to a strong interaction between the PP and PA molecules, thus decreasing the molecular mobility and increasing the crystallization temperature. The crystallization and melting of PP-PA mixtures are found to proceed at the close temperatures, although the crystallization and melting temperatures of pure PP and pure PA differ widely. The melting and crystallization enthalpies decrease with increasing PA concentration in the mixtures, which indicates a decrease in the degree of crystallinity of the composite.
NASA Astrophysics Data System (ADS)
Matthews, N. E.; Pyle, D. M.; Wilson, C. J.
2009-12-01
Chemical zoning of crystals provides an important archive of information that allows for the reconstruction of complex thermal histories and changes in melt composition of the magma reservoir during crystallization. Here we investigate cathodoluminescence (CL) and Ti zonation in quartz crystals extracted from pumices from the Whakamaru and Rangitaiki ignimbrite units (part of the large-volume Whakamaru Group Ignimbrites), New Zealand, to reconstruct the thermal history of the parent magma chamber(s). CL intensity images are taken as a proxy for Ti content and temperature variation during crystal growth, and direct estimates of temperature are made using the TitaniQ geothermometer (Wark & Watson 2006 Cont. Min. Pet.) based on Ti concentration in quartz. These results are reviewed in comparison with temperatures from Fe-Ti oxide geothermometry. Quartz zoning is also compared to zonation in feldspars (using BSE imaging) from the same pumice clasts in order to establish the degree to which different crystal species record similar or contrasting magmatic histories. Quartz crystals in Whakamaru pumice display a variety of CL zoning patterns and resorption boundaries. Overgrowths typically appear to truncate CL growth zoning within the crystal core, indicating periods of resorption and subsequent re-growth - consistent with magma recharge causing a marked change in conditions (temperature and/or volatile saturation) and multi-stage crystallisation. Crystals typically display a dark (lower Ti) resorbed core, with an abrupt change to a CL-bright rim, although irregular textures and complex variations between crystals are observed. Core-to-rim profiles of Ti concentration in analysed quartz crystals show Ti variations within the range 50-225 ppm, corresponding to crystallisation temperatures of 733-935°C (assuming TiO2 activity in the melt of 0.6), with the lowest values recorded in the crystal core, increasing in a step-wise pattern towards the rim. These values are consistent with Fe-Ti oxide temperature data for the same pumice clasts which provide a temperature range of 660-933°C. It is inferred that the major steps in Ti content (and thus CL brightness) represent short-term temperature fluctuations due to magma chamber recharge and rejuvenation of a crystal mush, while rim temperatures are likely to record the magma temperature at the time of eruption.
Solubility of carbamazepine co-crystals in ethanolic solution
NASA Astrophysics Data System (ADS)
Ramle, Noor Ashila; Rahim, Syarifah Abd; Anuar, Nornizar; El-Hadad, Omar
2017-08-01
The study aimed to determine the solubility of carbamazepine (CBZ) co-crystals formed from co-crystal formers (CCFs) of nicotinamide (NIC), saccharin (SAC), succinic acid (SUC) and fumaric acid (FUM) at various temperatures (25-50°C). High Performance Liquid Chromatography (HPLC) was used to determine the solubility and the X-Ray Powder Diffraction was used to characterize the crystals. The solubility of CBZ-NIC and CBZ-FUM co-crystals were found to be higher than the solubility of the CBZ for the range of studied temperatures. However, opposite findings was obtained for CBZ-SUC co-crystal as its solubility is lower than the solubility of CBZ. Different trend was found for CBZ-SAC co-crystal in which for temperature lower than 40°C, the solubility of CBZ crystal is higher than the CBZ-SAC co-crystal. The solubility of CBZ-SAC co-crystal is higher than the solubility of CBZ at a temperature above 40°C. CBZ co-crystals with NIC and FUM have shown to increase the solubility of CBZ by solubility ratio of 1.95 and 1.24 respectively. However, the CBZ co-crystal with SAC was found to have similar solubility value as the CBZ.
NASA Astrophysics Data System (ADS)
Jeong, Hyuncheol; Arnold, Craig; Priestley, Rodney
Polymer crystallization is strongly governed by kinetics where crystallization temperature (Tc) plays an important role in determining materials properties. Due to the high entropic barrier required for reorganization, the long-chain molecules typically form folded-chain crystals, whose thickness and thermal stability decrease as Tc is lowered. Interesting questions remain regarding crystallization in the deeply supercooled regime. This is partially due to the difficulty in accessing the low Tc range without nucleation. For a strong crystal-former like polyethylene (PE), cooling from a melt or solution always confronts the onset of nucleation at a high Tc followed by rapid crystal growth. Here, we introduce an alternative approach to grow polymer crystals via Matrix Assisted Pulsed Laser Evaporation (MAPLE). This methodology achieves the crystallization of polymers from a quasi-vapor phase at a controlled temperature, allowing for the study of the empirical relationship between Tc and crystal structure over a wide range of Tc. With PE as a model polymer, we investigated the morphological and thermal properties of crystals grown over a wide temperature range down to 120 °C below bulk crystallization point.
Time lapse microscopy of temperature control during self-assembly of 3D DNA crystals
NASA Astrophysics Data System (ADS)
Conn, Fiona W.; Jong, Michael Alexander; Tan, Andre; Tseng, Robert; Park, Eunice; Ohayon, Yoel P.; Sha, Ruojie; Mao, Chengde; Seeman, Nadrian C.
2017-10-01
DNA nanostructures are created by exploiting the high fidelity base-pairing interactions of double-stranded branched DNA molecules. These structures present a convenient medium for the self-assembly of macroscopic 3D crystals. In some self-assemblies in this system, crystals can be formed by lowering the temperature, and they can be dissolved by raising it. The ability to monitor the formation and melting of these crystals yields information that can be used to monitor crystal formation and growth. Here, we describe the development of an inexpensive tool that enables direct observation of the crystal growth process as a function of both time and temperature. Using the hanging-drop crystallization of the well-characterized 2-turn DNA tensegrity triangle motif for our model system, its response to temperature has been characterized visually.
NASA Astrophysics Data System (ADS)
MacCalman, M. L.; Roberts, K. J.; Hendriksen, B. A.
1993-03-01
The preparation of the nortriptyline hydrochloride, an important pharmaceutical product, by crystallization from both alcohol and aqueous solutions is presented. At low temperatures this material shows a higher solubility in absolute alcohol compared to aqueous solutions in a trend which reverses at higher temperatures. Examination of crystals prepared from alcohol solutions reveal essentially a needle-like crystal habit which is in excellent agreement with morphological predictions based on the bulk crystallographic structure. In contrast crystals prepared from aqueous solution at high temperatures reveal a particulate structure dominated by heavily agglomerated crystallites with plate-like morphology. When this material is crystallized at the lower temperatures, where the solubility curve is steep, X-ray and thermal analysis appear to show that crystallization results in a new polymorphic structure associated with a less agglomerated product.
Non-isothermal crystallization of poly(etheretherketone) aromatic polymer composite
NASA Technical Reports Server (NTRS)
Cebe, Peggy
1988-01-01
The nonisothermal crystallization kinetics of PEEK APC-2 and of 450G neat resin PEEK material were compared using a differential scanning calorimeter to monitor heat flow during crystallization; the effects of cooling rate on the crystallization temperature, the degree of crystallinity, and the conversion rate were investigated. A modified Avrami (1940) analysis was used to describe nonisothermal crystallization kinetics. It was found that, compared with the 450G neat resin PEEK, the nonisothermal crystallization of the PEEK APC-2 composite is characterized by higher initiation temperature, higher heat flow maximum temperature, and greater relative conversion by primary processes.
Photonic crystal fiber sensing characteristics research based on alcohol asymmetry filling
NASA Astrophysics Data System (ADS)
Shi, Fu-quan; Luo, Yan; Li, Hai-tao; Peng, Bao-jin
2018-02-01
A new type of Sagnac fiber temperature sensor based on alcohol asymmetric filling photonic crystal fiber is proposed. First, the corrosion of photonic crystal fiber and the treatment of air hole collapse are carried out. Then, the asymmetric structure of photonic crystal fiber is filled with alcohol, and then the structure is connected to the Sagnac interference ring. When the temperature changes, the thermal expansion effect of filling alcohol will lead to the change of birefringence of photonic crystal fiber, so that the interference spectrum of the sensor will drift along with the change of temperature. The experimental results show that the interference red shift will occur with the increase of temperature, and the temperature sensitivity is 0.1864nm/ °C. The sensor has high sensitivity to temperature. At the same time, the structure has the advantages of high stability, anti electromagnetic interference and easy to build. It provides a new method for obtaining birefringence in ordinary photonic crystal fibers.
Automated distress surveys : analysis of network-level data.
DOT National Transportation Integrated Search
2017-04-01
TxDOT Project 0-6663, Phase 1: Rutting : Applus, Dynatest, Fugro, Pathway and TxDOT : Reference: detailed project level (24 550-ft sections) : Phase 2: Distresses : Dynatest, Fugro, WayLink-OSU and TxDOT : Reference: detailed proj...
TxDOT administration research : tasks completed in FY2009.
DOT National Transportation Integrated Search
2010-01-01
Texas Department of Transportation (TxDOT) Project 0-6581-TI, TxDOT Administration : Research, encompasses multiple tasks that explore and support administrative aspects of : transportation research. : The project term began in October 2008 and has b...
Optimal Location of Marine Forces Reserve Units by Demographics
2014-06-01
significant portion of its subordinate units between fiscal years (FYs) 2012 and 2017 (see Figure 1). The decisions made during the FSRG most drastically...fiscal year 2017 . Figure 1. Planned 2010 FSRG MARFORRES restructuring, color-coded in terms of unit reorganizations, additions, deletions, and...Bossier City, LA Texarkana , TX a49 North Little Rock, AR a50 Harlingen, TX Naval Air Station Corpus Christi, TX a51 Ellington Field/Houston, TX
Determinants of Treatment Abandonment in Childhood Cancer: Results from a Global Survey
Lam, Catherine G.; Kaur, Geetinder; Itriago, Elena; Ribeiro, Raul C.; Arora, Ramandeep S.
2016-01-01
Background Understanding and addressing treatment abandonment (TxA) is crucial for bridging the pediatric cancer survival gap between high-income (HIC) and low-and middle-income countries (LMC). In childhood cancer, TxA is defined as failure to start or complete curative cancer therapy and known to be a complex phenomenon. With rising interest on causes and consequences of TxA in LMC, this study aimed to establish the lay-of-the-land regarding determinants of TxA globally, perform and promote comparative research, and raise awareness on this subject. Methods Physicians (medical oncologists, surgeons, and radiation therapists), nurses, social workers, and psychologists involved in care of children with cancer were approached through an online survey February-May 2012. Queries addressed social, economic, and treatment-related determinants of TxA. Free-text comments were collected. Descriptive and qualitative analyses were performed. Appraisal of overall frequency, burden, and predictors of TxA has been reported separately. Results 581 responses from 101 countries were obtained (contact rate = 26%, cooperation rate = 70%). Most respondents were physicians (86%), practicing pediatric hematology/oncology (86%) for >10 years (54%). Providers from LMC considered social/economic factors (families’ low socioeconomic status, low education, and long travel time), as most influential in increasing risk of TxA. Treatment-related considerations such as preference for complementary and alternative medicine and concerns about treatment adverse effects and toxicity, were perceived to play an important role in both LMC and HIC. Perceived prognosis seemed to mediate the role of other determinants such as diagnosis and treatment phase on TxA risk. For example, high-risk of TxA was most frequently reported when prognosis clearly worsened (i.e. lack of response to therapy, relapse), or conversely when the patient appeared improved (i.e. induction completed, mass removed), as well as before aggressive/mutilating surgery. Provider responses allowed development of an expanded conceptual model of determinants of TxA; one which illustrates established and emerging individual, family, center, and context specific factors to be considered in order to tackle this problem. Emerging factors included vulnerability, family dynamics, perceptions, center capacity, public awareness, and governmental healthcare financing, among others. Conclusion TxA is a complex and multifactorial phenomenon. With increased recognition of the role of TxA on global pediatric cancer outcomes, factors beyond social/economic status and beliefs have emerged. Our results provide insights regarding the role of established determinants of TxA in different geographical and economic contexts, allow probing of key determinants by deliberating their mechanisms, and allow building an expanded conceptual model of established and emerging determinants TxA. PMID:27736871
de Waard, Hans; De Beer, Thomas; Hinrichs, Wouter L J; Vervaet, Chris; Remon, Jean-Paul; Frijlink, Henderik W
2010-12-01
We developed a novel process, "controlled crystallization during freeze-drying" to produce drug nanocrystals of poorly water-soluble drugs. This process involves freeze-drying at a relatively high temperature of a drug and a matrix material from a mixture of tertiary butyl alcohol and water, resulting in drug nanocrystals incorporated in a matrix. The aim of this study was to elucidate the mechanisms that determine the size of the drug crystals. Fenofibrate was used as a model lipophilic drug. To monitor the crystallization during freeze-drying, a Raman probe was placed just above the sample in the freeze-dryer. These in-line Raman spectroscopy measurements clearly revealed when the different components crystallized during freeze-drying. The solvents crystallized only during the freezing step, while the solutes only crystallized after the temperature was increased, but before drying started. Although the solutes crystallized only after the freezing step, both the freezing rate and the shelf temperature were critical parameters that determined the final crystal size. At a higher freezing rate, smaller interstitial spaces containing the freeze-concentrated fraction were formed, resulting in smaller drug crystals (based on dissolution data). On the other hand, when the solutes crystallized at a lower shelf temperature, the degree of supersaturation is higher, resulting in a higher nucleation rate and consequently more and therefore smaller crystals. In conclusion, for the model drug fenofibrate, a high freezing rate and a relatively low crystallization temperature resulted in the smallest crystals and therefore the highest dissolution rate.
Study on the temperature field of large-sized sapphire single crystal furnace
NASA Astrophysics Data System (ADS)
Zhai, J. P.; Jiang, J. W.; Liu, K. G.; Peng, X. B.; Jian, D. L.; Li, I. L.
2018-01-01
In this paper, the temperature field of large-sized (120kg, 200kg and 300kg grade) sapphire single crystal furnace was simulated. By keeping the crucible diameter ratio and the insulation system unchanged, the power consumption, axial and radial temperature gradient, solid-liquid surface shape, stress distribution and melt flow were studied. The simulation results showed that with the increase of the single crystal furnace size, the power consumption increased, the temperature field insulation effect became worse, the growth stress value increased and the stress concentration phenomenon occurred. To solve these problems, the middle and bottom insulation system should be enhanced during designing the large-sized sapphire single crystal furnace. The appropriate radial and axial temperature gradient was favorable to reduce the crystal stress and prevent the occurrence of cracking. Expanding the interface between the seed and crystal was propitious to avoid the stress accumulation phenomenon.
History dependent crystallization of Zr41Ti14Cu12Ni10Be23 melts
NASA Astrophysics Data System (ADS)
Schroers, Jan; Johnson, William L.
2000-07-01
The crystallization of Zr41Ti14Cu12Ni10Be23 (Vit 1) melts during constant heating is investigated. (Vit 1) melts are cooled with different rates into the amorphous state and the crystallization temperature upon subsequent heating is studied. In addition, Vit 1 melts are cooled using a constant rate to different temperatures and subsequently heated from this temperature with a constant rate. We investigate the influence of the temperature to which the melt was cooled on the crystallization temperature measured upon heating. In both cases the onset temperature of crystallization shows strong history dependence. This can be explained by an accumulating process during cooling and heating. An attempt is made to consider this process in a simple model by steady state nucleation and subsequent growth of the nuclei which results in different crystallization kinetics during cooling or heating. Calculations show qualitative agreement with the experimental results. However, calculated and experimental results differ quantitatively. This difference can be explained by a decomposition process leading to a nonsteady nucleation rate which continuously increases with decreasing temperature.
Method for reducing energy losses in laser crystals
Atherton, L.J.; DeYoreo, J.J.; Roberts, D.H.
1992-03-24
A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light. 12 figs.
Method for reducing energy losses in laser crystals
Atherton, L. Jeffrey; DeYoreo, James J.; Roberts, David H.
1992-01-01
A process for reducing energy losses in crystals is disclosed which comprises: a. heating a crystal to a temperature sufficiently high as to cause dissolution of microscopic inclusions into the crystal, thereby converting said inclusions into point-defects, and b. maintaining said crystal at a given temperature for a period of time sufficient to cause said point-defects to diffuse out of said crystal. Also disclosed are crystals treated by the process, and lasers utilizing the crystals as a source of light.
Magnitude of Treatment Abandonment in Childhood Cancer.
Friedrich, Paola; Lam, Catherine G; Itriago, Elena; Perez, Rafael; Ribeiro, Raul C; Arora, Ramandeep S
2015-01-01
Treatment abandonment (TxA) is recognized as a leading cause of treatment failure for children with cancer in low-and-middle-income countries (LMC). However, its global frequency and burden have remained elusive due to lack of global data. This study aimed to obtain an estimate using survey and population data. Childhood cancer clinicians (medical oncologists, surgeons, and radiation therapists), nurses, social workers, and psychologists involved in care of children with cancer were approached through an online survey February-May 2012. Incidence and population data were obtained from public sources. Descriptive, univariable, and multivariable analyses were conducted. 602 responses from 101 countries were obtained from physicians (84%), practicing pediatric hematology/oncology (83%) in general or children's hospitals (79%). Results suggested, 23,854 (15%) of 155,088 children <15 years old newly diagnosed with cancer annually in the countries analyzed, abandon therapy. Importantly, 83% of new childhood cancer cases and 99% of TxA were attributable to LMC. The annual number of cases of TxA expected in LMC worldwide (26,166) was nearly equivalent to the annual number of cancer cases in children <15 years expected in HIC (26,368). Approximately two thirds of LMC had median TxA ≥ 6%, but TxA ≥ 6% was reported in high- (9%), upper-middle- (41%), lower-middle- (80%), and low-income countries (90%, p<0.001). Most LMC centers reporting TxA > 6% were outside the capital. Lower national income category, higher reliance on out-of-pocket payments, and high prevalence of economic hardship at the center were independent contextual predictors for TxA ≥ 6% (p<0.001). Global survival data available for more developed and less developed regions suggests TxA may account for at least a third of the survival gap between HIC and LMC. Results show TxA is prevalent (compromising cancer survival for 1 in 7 children globally), confirm the suspected high burden of TxA in LMC, and illustrate the negative impact of poverty on its occurrence. The present estimates may appear small compared to the global burden of child death from malnutrition and infection (measured in millions). However, absolute numbers suggest the burden of TxA in LMC is nearly equivalent to annually losing all kids diagnosed with cancer in HIC just to TxA, without even considering deaths from disease progression, relapse or toxicity-the main causes of childhood cancer mortality in HIC. Results document the importance of monitoring and addressing TxA as part of childhood cancer outcomes in at-risk settings.
A 2.4-GHz Energy-Efficient Transmitter for Wireless Medical Applications.
Qi Zhang; Peng Feng; Zhiqing Geng; Xiaozhou Yan; Nanjian Wu
2011-02-01
A 2.4-GHz energy-efficient transmitter (TX) for wireless medical applications is presented in this paper. It consists of four blocks: a phase-locked loop (PLL) synthesizer with a direct frequency presetting technique, a class-B power amplifier, a digital processor, and nonvolatile memory (NVM). The frequency presetting technique can accurately preset the carrier frequency of the voltage-controlled oscillator and reduce the lock-in time of the PLL synthesizer, further increasing the data rate of communication with low power consumption. The digital processor automatically compensates preset frequency variation with process, voltage, and temperature. The NVM stores the presetting signals and calibration data so that the TX can avoid the repetitive calibration process and save the energy in practical applications. The design is implemented in 0.18- μm radio-frequency complementary metal-oxide semiconductor process and the active area is 1.3 mm (2). The TX achieves 0-dBm output power with a maximum data rate of 4 Mb/s/2 Mb/s and dissipates 2.7-mA/5.4-mA current from a 1.8-V power supply for on-off keying/frequency-shift keying modulation, respectively. The corresponding energy efficiency is 1.2 nJ/b·mW and 4.8 nJ/b· mW when normalized to the transmitting power.
Electrical conductivity of high-purity germanium crystals at low temperature
NASA Astrophysics Data System (ADS)
Yang, Gang; Kooi, Kyler; Wang, Guojian; Mei, Hao; Li, Yangyang; Mei, Dongming
2018-05-01
The temperature dependence of electrical conductivity of single-crystal and polycrystalline high-purity germanium (HPGe) samples has been investigated in the temperature range from 7 to 100 K. The conductivity versus inverse of temperature curves for three single-crystal samples consist of two distinct temperature ranges: a high-temperature range where the conductivity increases to a maximum with decreasing temperature, and a low-temperature range where the conductivity continues decreasing slowly with decreasing temperature. In contrast, the conductivity versus inverse of temperature curves for three polycrystalline samples, in addition to a high- and a low-temperature range where a similar conductive behavior is shown, have a medium-temperature range where the conductivity decreases dramatically with decreasing temperature. The turning point temperature ({Tm}) which corresponds to the maximum values of the conductivity on the conductivity versus inverse of temperature curves are higher for the polycrystalline samples than for the single-crystal samples. Additionally, the net carrier concentrations of all samples have been calculated based on measured conductivity in the whole measurement temperature range. The calculated results show that the ionized carrier concentration increases with increasing temperature due to thermal excitation, but it reaches saturation around 40 K for the single-crystal samples and 70 K for the polycrystalline samples. All these differences between the single-crystal samples and the polycrystalline samples could be attributed to trapping and scattering effects of the grain boundaries on the charge carriers. The relevant physical models have been proposed to explain these differences in the conductive behaviors between two kinds of samples.
NASA Astrophysics Data System (ADS)
Magee, N.; Moyle, A.; Lamb, D.
2003-12-01
An improved understanding of ice crystal growth, particularly at low temperatures, is much in demand for the advancement of numerical modeling of atmospheric processes. Cirrus models must contend with the complexity of ice crystals growing in cold temperatures, low pressures, low supersaturations, and with multiple nucleation mechanisms. Recent observations have allowed increasingly realistic parameterizations of cirrus ice crystal microphysics, but these observations need to be supplemented by a fundamental understanding of growth processes affecting low-temperature crystals. Several experimental studies have demonstrated that certain ice crystals require a minimum "critical" supersaturation before exhibiting detectable growth. These crystals are presumed to be essentially defect-free, preventing vicinal hillock growth at the site of crystal dislocations. In the case of crystal growth by spiral dislocation, advancement of faces begins as soon as supersaturation is present. The finding of conditional critical supersaturations have analogies in other materials (metals, semiconductors, potassium dihydrogen phosphate) and are thermodynamically predicted given a two-dimensional nucleation growth mechanism. Previous measurements have determined the critical supersaturation for ice as a function of temperature and crystallographic face from 0 to --15° C with extrapolation to --30° C. For both basal and prism faces, critical supersaturation is seen to increase with decreasing temperature, suggesting that low-temperature, low-supersaturation processes are most likely to be affected by this critical contingency. We present laboratory results to verify and extend prior critical supersaturation measurements using a novel approach for supersaturation generation, control, and measurement. The crystals are grown on the tip of a fine glass fiber ( ˜10 microns in diameter) under varying conditions of temperature, pressure, and saturation. Supersaturation is generated when a pre-saturated airflow passes over a coil of ice warmed by electrical resistance upstream from the growing crystal. Supersaturation is determined by a system of differential thermocouples calibrated to sulfuric acid drop size measurements. Measurements follow those made in earlier studies, but also extend to temperatures of --45° C, mimicking conditions found in some high altitude clouds.
Krock, Bernd; Busch, Julia A; Tillmann, Urban; García-Camacho, Francisco; Sánchez-Mirón, Asterio; Gallardo-Rodríguez, Juan J; López-Rosales, Lorenzo; Andree, Karl B; Fernández-Tejedor, Margarita; Witt, Matthias; Cembella, Allan D; Place, Allen R
2017-12-18
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the detection and quantitation of karlotoxins in the selected reaction monitoring (SRM) mode. This novel method was based upon the analysis of purified karlotoxins (KcTx-1, KmTx-2, 44-oxo-KmTx-2, KmTx-5), one amphidinol (AM-18), and unpurified extracts of bulk cultures of the marine dinoflagellate Karlodinium veneficum strain CCMP2936 from Delaware (Eastern USA), which produces KmTx-1 and KmTx-3. The limit of detection of the SRM method for KmTx-2 was determined as 2.5 ng on-column. Collision induced dissociation (CID) spectra of all putative karlotoxins were recorded to present fragmentation patterns of each compound for their unambiguous identification. Bulk cultures of K. veneficum strain K10 isolated from an embayment of the Ebro Delta, NW Mediterranean, yielded five previously unreported putative karlotoxins with molecular masses 1280, 1298, 1332, 1356, and 1400 Da, and similar fragments to KmTx-5. Analysis of several isolates of K. veneficum from the Ebro Delta revealed small-scale diversity in the karlotoxin spectrum in that one isolate from Fangar Bay produced KmTx-5, whereas the five putative novel karlotoxins were found among several isolates from nearby, but hydrographically distinct Alfacs Bay. Application of this LC-MS/MS method represents an incremental advance in the determination of putative karlotoxins, particularly in the absence of a complete spectrum of purified analytical standards of known specific potency.
Krock, Bernd; Busch, Julia A.; García-Camacho, Francisco; Sánchez-Mirón, Asterio; Gallardo-Rodríguez, Juan J.; López-Rosales, Lorenzo; Andree, Karl B.; Fernández-Tejedor, Margarita; Witt, Matthias; Place, Allen R.
2017-01-01
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the detection and quantitation of karlotoxins in the selected reaction monitoring (SRM) mode. This novel method was based upon the analysis of purified karlotoxins (KcTx-1, KmTx-2, 44-oxo-KmTx-2, KmTx-5), one amphidinol (AM-18), and unpurified extracts of bulk cultures of the marine dinoflagellate Karlodinium veneficum strain CCMP2936 from Delaware (Eastern USA), which produces KmTx-1 and KmTx-3. The limit of detection of the SRM method for KmTx-2 was determined as 2.5 ng on-column. Collision induced dissociation (CID) spectra of all putative karlotoxins were recorded to present fragmentation patterns of each compound for their unambiguous identification. Bulk cultures of K. veneficum strain K10 isolated from an embayment of the Ebro Delta, NW Mediterranean, yielded five previously unreported putative karlotoxins with molecular masses 1280, 1298, 1332, 1356, and 1400 Da, and similar fragments to KmTx-5. Analysis of several isolates of K. veneficum from the Ebro Delta revealed small-scale diversity in the karlotoxin spectrum in that one isolate from Fangar Bay produced KmTx-5, whereas the five putative novel karlotoxins were found among several isolates from nearby, but hydrographically distinct Alfacs Bay. Application of this LC-MS/MS method represents an incremental advance in the determination of putative karlotoxins, particularly in the absence of a complete spectrum of purified analytical standards of known specific potency. PMID:29258236
Method of casting articles of a bulk-solidifying amorphous alloy
Lin, X.; Johnson, W.L.; Peker, A.
1998-08-25
A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast. 8 figs.
Method of casting articles of a bulk-solidifying amorphous alloy
Lin, Xianghong; Johnson, William L.; Peker, Atakan
1998-01-01
A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast.
Zhang, Yifan; Dai, Yifan; Tie, Guipeng; Hu, Hao
2016-10-10
As a kind of important nonlinear optical element, KDP crystal has great demand in the inertial confinement fusion system. Based on the dissolution mechanism of solid materials, the factors that affect the material removal rate of KDP crystal in magnetorheological (MR) water-dissolution polishing are investigated to improve the machining efficiency. It is found that the material removal rate is proportional to the product of the saturation concentration and diffusion coefficient, and the relationship between the removal efficiency and the temperature meets the unilateral Gaussian function. Polishing experiments are carried out on a magnetorheological finishing (MRF) machine with self-designed MRF fluid heating devices. The experimental results show that practical efficiency-temperature curve is consistent with the theoretical curve, and the maximum machining efficiency increases by about 50% with the rise of temperature from 294 to 302 K. Meanwhile, when the MR fluid temperature is lower than 308 K, the crystal surface quality and surface roughness in different processing temperatures have no remarkable difference with constant crystal temperature (294 K). This research indicates that it is feasible to drastically improve KDP crystal MRF efficiency by controlling the processing temperature.
Effect of temperature gradient on the optical quality of mercurous chloride crystals
NASA Technical Reports Server (NTRS)
Singh, N. B.; Davies, D. K.; Gottlieb, M.; Henningsen, T.; Mazelsky, R.
1989-01-01
Single crystals of mercurous chloride were grown at temperature gradients of 8, 11 and 17 K/cm by the physical vapor transport method. The optical quality of these crystals was evaluated by measuring bulk scattering and inhomogeneity of refractive index by birefringence interferometry. It was observed that a high temperature gradient at the solid-vapor interface induced thermal stresses and crystals showed higher scattering and irregular fringes.
NASA Astrophysics Data System (ADS)
Saidaminov, Makhsud I.; Abdelhady, Ahmed L.; Murali, Banavoth; Alarousu, Erkki; Burlakov, Victor M.; Peng, Wei; Dursun, Ibrahim; Wang, Lingfei; He, Yao; Maculan, Giacomo; Goriely, Alain; Wu, Tom; Mohammed, Omar F.; Bakr, Osman M.
2015-07-01
Single crystals of methylammonium lead trihalide perovskites (MAPbX3; MA=CH3NH3+, X=Br- or I-) have shown remarkably low trap density and charge transport properties; however, growth of such high-quality semiconductors is a time-consuming process. Here we present a rapid crystal growth process to obtain MAPbX3 single crystals, an order of magnitude faster than previous reports. The process is based on our observation of the substantial decrease of MAPbX3 solubility, in certain solvents, at elevated temperatures. The crystals can be both size- and shape-controlled by manipulating the different crystallization parameters. Despite the rapidity of the method, the grown crystals exhibit transport properties and trap densities comparable to the highest quality MAPbX3 reported to date. The phenomenon of inverse or retrograde solubility and its correlated inverse temperature crystallization strategy present a major step forward for advancing the field on perovskite crystallization.
Case study of Pampa, Texas, multicell storms
NASA Technical Reports Server (NTRS)
Hung, R. J.; Tsao, D. Y.; Smith, R. E.
1983-01-01
Analysis of the Pampa, TX, multicell storms showed prestorm environmental conditions of a strong horizontal convergence of moisture, mixing ratio 12 g/kg at the 850 mb level in the Texas Panhandle areas and strong winds with shear veering with height. Rapid-scan satellite imagery showed that the clouds penetrated above the tropopause and cloud-top temperatures were at least 4 to 9 C colder than the temperature of the tropopause. This formation and collapsing of high-mass-density overshooting cloud tops above the tropopause is characteristic of tornadoes in the middle portion of the United States.
NASA Technical Reports Server (NTRS)
Wallace, D. A.
1980-01-01
A thermoelectrically temperature controlled quartz crystal microbalance (QCM) system was developed for the measurement of ion thrustor generated mercury contamination on spacecraft. Meaningful flux rate measurements dictated an accurately held sensing crystal temperature despite spacecraft surface temperature variations from -35 C to +60 C over the flight temperature range. An electronic control unit was developed with magentic amplifier transformer secondary power supply, thermal control electronics, crystal temperature analog conditioning and a multiplexed 16 bit frequency encoder.
TX-100 manufacturing final project report.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ashwill, Thomas D.; Berry, Derek S.
This report details the work completed under the TX-100 blade manufacturing portion of the Carbon-Hybrid Blade Developments: Standard and Twist-Coupled Prototype project. The TX-100 blade is a 9 meter prototype blade designed with bend-twist coupling to augment the mitigation of peak loads during normal turbine operation. This structural coupling was achieved by locating off axis carbon fiber in the outboard portion of the blade skins. The report will present the tooling selection, blade production, blade instrumentation, blade shipping and adapter plate design and fabrication. The baseline blade used for this project was the ERS-100 (Revision D) wind turbine blade. Themore » molds used for the production of the TX-100 were originally built for the production of the CX-100 blade. The same high pressure and low pressure skin molds were used to manufacture the TX-100 skins. In order to compensate for the difference in skin thickness between the CX-100 and the TX-100, however, a new TX-100 shear web plug and mold were required. Both the blade assembly fixture and the root stud insertion fixture used for the CX-100 blades could be utilized for the TX-100 blades. A production run of seven TX-100 prototype blades was undertaken at TPI Composites during the month of October, 2004. Of those seven blades, four were instrumented with strain gauges before final assembly. After production at the TPI Composites facility in Rhode Island, the blades were shipped to various test sites: two blades to the National Wind Technology Center at the National Renewable Energy Laboratory in Boulder, Colorado, two blades to Sandia National Laboratory in Albuquerque, New Mexico and three blades to the United States Department of Agriculture turbine field test facility in Bushland, Texas. An adapter plate was designed to allow the TX-100 blades to be installed on existing Micon 65/13M turbines at the USDA site. The conclusion of this program is the kick-off of the TX-100 blade testing at the three testing facilities.« less
NASA Astrophysics Data System (ADS)
Lioi, David B.
In this thesis I investigate the relationship between the charge density wave (CDW) phase and superconductivity in the T-x phase diagram of Cu xTiSe2. I find that the incommensurate (IC)-CDW is related to the superconducting phase due to the fact that the former effectively isolates the CDW subsystem degrees of freedom. This increases the symmetry of the electronic populations within the IC-CDW band structure and leave them susceptible to internal instabilities, which in turn give rise to the superconducting phase. Because the correlated properties of these solid-state phases of matter are highly dependent on the crystalline quality of our samples, I also detail the growth of pristine single crystals and utilize several characterization techniques to aid in this purpose. In this portion of the thesis the single crystals are deliberately injected with heat and monitored to deduce the formation of defects through selenium migration. I also confirm the existence of chiral symmetry breaking in the bulk commensurate (C)-CDW phase in TiSe2 brought about by the cooperation of phonon and exciton degrees of freedom, and also observe chiral character in fluctuations above TCDW. These thermal fluctuations were observed up to 80 K above TCDW via optical signatures of the folded Se-4p band and Raman signatures of the soft L1- phonon mode. The suppression of the excitonic degree of freedom with Cu intercalation brings about a quantum phase transition into the IC-CDW at x=0.04. Large quantum fluctuations of the folded Se-4p electronic band were observed at the quantum phase transition where measurements of the phonon system show the onset of incommensuration in the CDW super-lattice. Optical measurements demonstrate a large decoupling of the electron-phonon degrees of freedom within the electronic band structure of the IC-CDW subsystem.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Perumal, R., E-mail: perumal-cgc@yahoo.co.uk; Chandru, A. Lakshmi; Babu, S. Moorthy
The Glycinium Phosphite (GPI) compound is a representative of hydrogen-bonded ferroelectric crystals. The ordering of protons could be expected below the room temperature (225 K). Crystals grown from the milipore water as well as deuterated solvents respectively. The corresponding hydrogen bond distance was stretched out due to the effect of isotopic substitution that increase the phase transition temperature. Further to improve the phase transition temperature, GPI crystal was doped with organic complexing agent and various metals and the obtained results are presented.
Method for single crystal growth of photovoltaic perovskite material and devices
DOE Office of Scientific and Technical Information (OSTI.GOV)
Huang, Jinsong; Dong, Qingfeng
Systems and methods for perovskite single crystal growth include using a low temperature solution process that employs a temperature gradient in a perovskite solution in a container, also including at least one small perovskite single crystal, and a substrate in the solution upon which substrate a perovskite crystal nucleates and grows, in part due to the temperature gradient in the solution and in part due to a temperature gradient in the substrate. For example, a top portion of the substrate external to the solution may be cooled.
Three dimensional reflectance properties of superconductor-dielectric photonic crystal
DOE Office of Scientific and Technical Information (OSTI.GOV)
Pandey, G. N., E-mail: gnpandey@amity.edu; Sancheti, Bhagyashree; Pandey, J. P.
2016-05-06
In this present communication, we have studied the optical properties of Photonics Crystals with super conducting constituent using the TMM method for a stratified medium. We also studied the three dimensional reflectance property of superconductor-dielectric photonic crystal at different temperature and thickness. From above study we show that the superconductor-dielectric photonic crystal may be used as broad band reflector and omnidirectional reflector at low temperature below to the critical temperature. Such property may be applied to make of the reflector which can be used in low temperature region.
Evaluation of costs to process and manage utility and driveway permits.
DOT National Transportation Integrated Search
2014-10-01
Reviewing and processing utility and driveway permits at the Texas Department of Transportation (TxDOT) : requires a considerable amount of involvement and coordination by TxDOT personnel, both at the district : and division levels. Currently, TxDOT ...
Executive plan summary, an ITS strategic plan for Texas.
DOT National Transportation Integrated Search
2016-07-01
The TxDOT ITS Strategic Plan supports the goals and objectives of the TxDOT agency Strategic : Plan. It has the same four goals as the TxDOT Strategic Plan: : - Maintain a safe system. : - Address congestion. : - Connect Texas communities. : - Become...
TxDOT uses of real-time commercial traffic data : opportunity matrix.
DOT National Transportation Integrated Search
2012-01-01
Based on a TxDOT survey, a review of other state DOTs, and researcher understanding of Intelligent Transportation System (ITS) needs, the Texas Transportation Institute (TTI) team developed a comprehensive list of opportunities for TxDOT to consider ...
Botha, Sabine; Nass, Karol; Barends, Thomas R M; Kabsch, Wolfgang; Latz, Beatrice; Dworkowski, Florian; Foucar, Lutz; Panepucci, Ezequiel; Wang, Meitian; Shoeman, Robert L; Schlichting, Ilme; Doak, R Bruce
2015-02-01
Recent advances in synchrotron sources, beamline optics and detectors are driving a renaissance in room-temperature data collection. The underlying impetus is the recognition that conformational differences are observed in functionally important regions of structures determined using crystals kept at ambient as opposed to cryogenic temperature during data collection. In addition, room-temperature measurements enable time-resolved studies and eliminate the need to find suitable cryoprotectants. Since radiation damage limits the high-resolution data that can be obtained from a single crystal, especially at room temperature, data are typically collected in a serial fashion using a number of crystals to spread the total dose over the entire ensemble. Several approaches have been developed over the years to efficiently exchange crystals for room-temperature data collection. These include in situ collection in trays, chips and capillary mounts. Here, the use of a slowly flowing microscopic stream for crystal delivery is demonstrated, resulting in extremely high-throughput delivery of crystals into the X-ray beam. This free-stream technology, which was originally developed for serial femtosecond crystallography at X-ray free-electron lasers, is here adapted to serial crystallography at synchrotrons. By embedding the crystals in a high-viscosity carrier stream, high-resolution room-temperature studies can be conducted at atmospheric pressure using the unattenuated X-ray beam, thus permitting the analysis of small or weakly scattering crystals. The high-viscosity extrusion injector is described, as is its use to collect high-resolution serial data from native and heavy-atom-derivatized lysozyme crystals at the Swiss Light Source using less than half a milligram of protein crystals. The room-temperature serial data allow de novo structure determination. The crystal size used in this proof-of-principle experiment was dictated by the available flux density. However, upcoming developments in beamline optics, detectors and synchrotron sources will enable the use of true microcrystals. This high-throughput, high-dose-rate methodology provides a new route to investigating the structure and dynamics of macromolecules at ambient temperature.
Unusual Crystallization Behavior Close to the Glass Transition
NASA Astrophysics Data System (ADS)
Desgranges, Caroline; Delhommelle, Jerome
2018-03-01
Using molecular simulations, we shed light on the mechanism underlying crystal nucleation in metal alloys and unravel the interplay between crystal nucleation and glass transition, as the conditions of crystallization lie close to this transition. While decreasing the temperature of crystallization usually results in a lower free energy barrier, we find an unexpected reversal of behavior for glass-forming alloys as the temperature of crystallization approaches the glass transition. For this purpose, we simulate the crystallization process in two glass-forming Copper alloys, Ag6 Cu4 , which has a positive heat of mixing, and CuZr, characterized by a large negative heat of mixing. Our results allow us to identify this unusual behavior as directly correlated with a nonmonotonic temperature dependence for the formation energy of connected icosahedral structures, which are incompatible with crystalline order and impede the development of the crystal nucleus, leading to an unexpectedly larger free energy barrier at low temperature. This, in turn, promotes the formation of a predominantly closed-packed critical nucleus, with fewer defects, thereby suggesting a new way to control the structure of the crystal nucleus, which is of key importance in catalysis.
Wide-band-gap, alkaline-earth-oxide semiconductor and devices utilizing same
Abraham, Marvin M.; Chen, Yok; Kernohan, Robert H.
1981-01-01
This invention relates to novel and comparatively inexpensive semiconductor devices utilizing semiconducting alkaline-earth-oxide crystals doped with alkali metal. The semiconducting crystals are produced by a simple and relatively inexpensive process. As a specific example, a high-purity lithium-doped MgO crystal is grown by conventional techniques. The crystal then is heated in an oxygen-containing atmosphere to form many [Li].degree. defects therein, and the resulting defect-rich hot crystal is promptly quenched to render the defects stable at room temperature and temperatures well above the same. Quenching can be effected conveniently by contacting the hot crystal with room-temperature air.
Pfaffenrot, Viktor; Brunheim, Sascha; Rietsch, Stefan H G; Koopmans, Peter J; Ernst, Thomas M; Kraff, Oliver; Orzada, Stephan; Quick, Harald H
2018-02-09
To design and evaluate an 8/15-channel transmit/receive (Tx/Rx) head-neck RF coil combination with region-specific B1+ shimming for whole-brain MRI with focus on improved functional MRI of the cerebellum at 7 T. An 8-channel transceiver RF head coil was combined with a 7-channel receive-only array. The noise parameters and acceleration capabilities of this 8Tx/15Rx coil setup were compared with a commercially available 1Tx/32Rx RF head coil. Region-specific 8-channel B1+ shimming was applied when using the 8Tx/15Rx RF coil. To evaluate the capability for functional MRI of the cerebellum, temporal SNR and statistical nonparametric maps for finger-tapping experiments with 14 healthy subjects were derived by applying a variable slice thickness gradient-echo echo-planar functional MRI sequence. The 8Tx/15Rx setup had a lower maximum noise correlation between channels, but higher average correlations compared with the 1Tx/32Rx coil. Both RF coils exhibited identical g-factors in the cerebellum with R = 3 acceleration. The enlarged FOV of the 8Tx/15Rx coil in combination with region-specific B1+ shimming increased homogeneity of the transmission field and temporal SNR in caudal cerebellar regions. Temporal SNR losses in cranial parts were reduced, resulting in more highly significant voxels in the caudally activated areas and identical patterns in the cranial cerebellar parts during a finger-tapping task. Compared with the 1Tx/32Rx RF coil, the presented 8Tx/15Rx RF coil combination successfully improves functional MRI of the human cerebellum at 7 T while maintaining whole-brain coverage. A clear temporal SNR gain in caudal cerebellar regions is shown. © 2018 International Society for Magnetic Resonance in Medicine.
Kurtulus, F O; Salman, M Y; Fazlioglu, A; Fazlioglu, B
2017-11-01
Sexual dysfunction occurs commonly in individuals with end-stage renal disease. Chronic renal failure as well as the treatments used for it generally has a negative impact on sexual function with a subsequent increase in the risk of depression. There is scarcity of published data on female sexual dysfunction and the degree of improvement in patients on hemodialysis (HD) and transplant (Tx) recipients. The aim of this study was to compare the sexual function and degree of depression in HD and Tx patients with control group. For this purpose, we used the validated Female Sexual Function Index (FSFI) and Beck Depression Inventory (BDI). A total of 23 renal Tx, 29 HD, and 30 control patients were enrolled in the study. HD patients were required to be undergoing HD for ≥6 months, and for renal Tx recipients, the Tx had to be performed ≥6 months before study entry. All women underwent a general and urogynecologic examination. Demographic and clinical variables were documented. FSFI and BDI scale scores were compared among groups. The rates of female sexual dysfunction were 56.7%, 89.7%, and 73.9% in the control, HD, and Tx, patients respectively. Total FSFI scores in HD group were significantly lower than those in Tx and control patients (P < .05). FSFI scores improved significantly in the Tx group. BDI scores in HD and control subjects were 23.24 and 14.17, respectively, with a significant difference between the 2 groups (P < .005). BDI score in the Tx group was 16.65 and the difference was statistically insignificant. This preliminary study documented that successful Tx may positively affect sexual life in women with chronic renal failure. A diagnosis of female sexual dysfunction should be made routinely in patients with chronic renal failure. Copyright © 2017 Elsevier Inc. All rights reserved.
Relja, Borna; Wagner, Nils; Franz, Niklas; Dieteren, Scott; Mörs, Katharina; Schmidt, Julia; Marzi, Ingo; Perl, Mario
2018-03-01
After blunt thoracic trauma (TxT) and hemorrhagic shock with resuscitation (H/R) intense local inflammatory response and cell loss frequently impair the pulmonary function. Ethyl pyruvate (EP) has been reported to improve the pathophysiologic derangements in models of acute inflammation. Here, we studied the effects of EP on inflammation and lung damage after TxT+H/R. Twenty four female Lewis rats (180-240g) were randomly divided into 3 groups: two groups underwent TxT followed by hemorrhagic shock (35±3mmHg) for 60min and resuscitation with either Ringers-Lactat (RL) alone or RL supplemented with EP (EP, 50mg/kg). Sham operated animals underwent surgical procedures. Two hours later bronchoalveolar lavage fluid (BAL), lung tissue and blood were collected for analyses. EP significantly improved pO 2 levels compared to RL after TxT+H/R. TxT+H/R induced elevated levels of lactate dehydrogenase, total protein concentration in BAL and lung damage as evidenced by lung histology; these effects were significantly reduced by EP. Local inflammatory markers, lung TNF-alpha protein levels and infiltration with polymorphonuclear leukocytes (PMNL) significantly decreased in EP vs. RL group after TxT+H/R. Indicators of apoptosis as reduced BCL-2 and increased FAS gene expression after TxT+H/R were significantly increased or decreased, respectively, by EP after TxT+H/R. EP reduced TxT+H/R-induced p65 phosphorylation, which was concomitant with reduced HMGB1 levels in lung sections. Taken together, TxT+H/R induced strong inflammatory response and apoptotic changes as well as lung injury which were markedly diminished by EP. Our results suggest that this might be mediated via NF-κB and/or HMGB1 dependent mechanism. Copyright © 2017 Elsevier GmbH. All rights reserved.
Two-Dimensional Titanium Carbide/RGO Composite for High-Performance Supercapacitors.
Zhao, Chongjun; Wang, Qian; Zhang, Huang; Passerini, Stefano; Qian, Xiuzhen
2016-06-22
Ti3C2Tx, a 2D titanium carbide in the MXenes family, is obtained from Ti3AlC2 through selective etching of the Al layer. Due to its good conductivity and high volumetric capacitance, Ti3C2Tx is regarded as a promising candidate for supercapacitors. In this paper, the fabrication of Ti3C2Tx/RGO composites with different proportions of Ti3C2Tx and RGO is reported, in which RGO acts as a conductive "bridge" to connect different Ti3C2Tx blocks and a matrix to alleviate the volume change during charge/discharge process. In addition, RGO nanosheets can serve as a second nanoscale current collector and support as well for the electrode. The electrochemical performance of the as-fabricated Ti3C2Tx/RGO electrodes, characterized by CV, GCD, and EIS, are also reported. A highest specific capacitance (Cs) of 154.3 F/g at 2 A/g is obtained at the Ti3C2Tx: RGO weight ratio of 7:1 combined with an outstanding capacity retention (124.7 F/g) after 6000 cycles at 4 A/g.
Pizzo, Andrea B; Beleboni, Renê O; Gomes Carolino, Ruither O; de Oliveira, Luciana; Miranda, Antonio; Coutinho-Netto, Joaquim; Fontana, Andréia C K; Dos Santos, Wagner Ferreira
2017-10-01
Arthropod venoms are sources of molecules that may be useful tools to investigate molecular mechanisms of putative new medicines and laboratory drugs. Here we show the effects of the compound agelaiatoxin-8 (AVTx8), isolated from Agelaia vicina venom, on γ-aminobutyric acid (GABA) neurotransmission in rat brain synaptosomes. Analysis reveals that AvTx8 is composed by 14 amino acid residues with a molecular weight (MW) of 1567 Da. AvTx8 increased GABA release and inhibited GABA uptake in synaptosomes from rat cerebral cortex. AvTx8 inhibited GABA uptake and increased GABA release in the presence of Ca + , Na + , and K + channel blockers, suggesting that it acts directly on GABA transporters. In addition, AvTx8 significantly decreases GABA binding in synaptic membranes from rat brain cortex, suggesting that it also modulates the activity of GABA receptors. Moreover, AvTx8 decreased GAT-1- and GAT-3-mediated GABA uptake in transfected COS-7 cells. Accordingly, we suggest that AvTx8 modulates GABA neurotransmission and might provide a novel entry point for identifying a new class of GABA-modulating neuroprotective drugs. © 2017 Wiley Periodicals, Inc.
Impact of simultaneous pancreas-kidney transplantation: patients' perspectives.
Isla Pera, P; Moncho Vasallo, J; Guasch Andreu, O; Ricart Brulles, Mj; Torras Rabasa, A
2012-01-01
Few qualitative studies of simultaneous pancreas-kidney transplantation (SPK Tx) have been published. The aims of this study were to explore from the perspective of patients, the experience of living with diabetes mellitus type 1 (T1DM), suffering from complications, and undergoing SPK Tx with good outcome; and to determine the impact of SPK Tx on patients and their social and cultural environment. We performed a focused ethnographic study. Twenty patients were interviewed. Data were analyzed using content analysis and constant comparison following the method proposed by Miles and Huberman. A functioning SPK Tx allowed renal replacement therapy and insulin to be discontinued. To describe their new situation, patients used words and phrases such as "miracle", "being reborn" or "coming back to life". Although the complications of T1DM, its surgery and treatment, and associated psychological problems did not disappear after SPK Tx, these were minimized when compared with the pretransplantation situation. For patients, SPK Tx represents a recovery of their health and autonomy despite remaining problems associated with the complications of T1DM and SPK Tx. The understanding of patients' existential framework and their experience of disease are key factors for planning new intervention and improvement strategies.
Fuscaldi, Leonardo Lima; Dos Santos, Daniel Moreira; Pinheiro, Natália Gabriela Silva; Araújo, Raquel Silva; de Barros, André Luís Branco; Resende, Jarbas Magalhães; Fernandes, Simone Odília Antunes; de Lima, Maria Elena; Cardoso, Valbert Nascimento
2016-01-01
Current diagnostic methods and imaging techniques are not able to differentiate septic and aseptic inflammation. Thus, reliable methods are sought to provide this distinction and scintigraphic imaging is an interesting option, since it is based on physiological changes. In this context, radiolabeled antimicrobial peptides have been investigated as they accumulate in infectious sites instead of aseptic inflammation. The peptide LyeTx I, from the venom of Lycosa erythrognatha, has potent antimicrobial activity. Therefore, this study aimed to synthesize LyeTx I derivatives with the chelating compound HYNIC, to evaluate their antimicrobial activity and to radiolabel them with (99m)Tc. Two LyeTx I derivatives, HYNIC-LyeTx I (N-terminal modification) and LyeTx I-K-HYNIC (C-terminal modification), were synthesized by Fmoc strategy and purified by RP-HPLC. The purified products were assessed by RP-HPLC and MALDI-ToF-MS analysis. Microbiological assays were performed against S. aureus (ATCC® 6538) and E. coli (ATCC® 10536) in liquid medium to calculate the MIC. The radiolabeling procedure of LyeTx I-K-HYNIC with (99m)Tc was performed in the presence of co-ligands (tricine and EDDA) and reducing agent (SnCl2 (.) 2H2O), and standardized taking into account the amount of peptide, reducing agent, pH and heating. Radiochemical purity analysis was performed by thin-layer chromatography on silica gel strips and the radiolabeled compound was assessed by RP-HPLC and radioactivity measurement of the collected fractions. Data were analyzed by ANOVA, followed by Tukey test (p-values < 0.05). Both LyeTx I derivatives were suitably synthesized and purified, as shown by RP-HPLC and MALDI-ToF-MS analysis. The microbiological test showed that HYNIC-LyeTx I (N-terminal modification) did not inhibit bacterial growth, whereas LyeTx I-K-HYNIC (C-terminal modification) showed a MIC of 5.05 μmol(.)L(-1) (S. aureus) and 10.10 μmol(.)L(-1) (E. coli). Thus, only the latter was radiolabeled with (99m)Tc. The radiochemical purity analysis of LyeTx I-K-HYNIC-(99m)Tc showed that the optimal radiolabeling conditions (10 μg of LyeTx I-K-HYNIC; 250 μg of SnCl2 (.) 2H2O; pH = 7; heating for 15 min) yielded a radiochemical purity of 87 ± 1 % (n = 3). However, RP-HPLC data suggested (99m)Tc transchelation from LyeTx I-K-HYNIC to the co-ligands (tricine and EDDA). The binding of HYNIC to the N-terminal portion of LyeTx I seems to affect its activity against bacteria. Nevertheless, the radiolabeling of the C-terminal derivative, LyeTx I-K-HYNIC, must be better investigated to optimize the radiolabeled compound, in order to use it as a specific imaging agent to distinguish septic and aseptic inflammation.
Mihara, Hiroaki; Ishiguro, Takashi; Fukano, Hidenori; Taniuchi, Shigeyuki; Ogino, Keizo
2007-01-01
Triacylglycerin in Palm Oil contains POP (1,3-dipalmitoyl-2-oleoyl-glycerol) at 30%, POO (1,2-dioleoyl-3-palmitoyl-glycerol) at 20% and PPP (tripalmitoylglycerol) at 5%. The crystallization temperature of PPP is high and the rates of crystal nuclear formation and growth are fast. It is thus considered that PPP may have some effect on the manner or mode of Palm Oil. Examination was thus made to clarify how PPP may affect the crystallization of POP and POO by differential scanning calorimetry (DSC) and X ray diffractometry (XRD) conducted on PPP/POP and PPP/POO mixtures. High and low temperature peaks were noted to appear on the DSC crystallization curve for either of these mixtures. The high temperature peak was considered possibly due to PPP, and the low temperature peak, to POP or POO. DSC isothermal analysis indicated the rate of crystal growth of either mixture to exceed that of pure of POP or POO. Crystal mixture structure was also seen to be complicated than either compound in pure form. The present findings thus clearly indicate that clarification should be made of the effects of high melting point triacylglycerin, such as PPP, on the crystallization of Palm Oil.
Effectiveness Comparison of TxDOT Quality Control/Quality Assurance and Method Specifications
DOT National Transportation Integrated Search
1998-12-01
Original Report date: October 1997. This is the first and final report for research project 0-1721, "Effectiveness Comparison of TxDOT Quality Control/Quality Assurance and Method Specifications." This study was established and sponsored by TxDOT to ...
Crystallization of Chicken Egg-White Lysozyme from Ammonium Sulfate
NASA Technical Reports Server (NTRS)
Forsythe, Elizabeth L.; Snell, Edward H.; Pusey, Marc L.
1997-01-01
Chicken egg-white lysozyme was crystallized from ammonium sulfate over the pH range 4.0-7.8, with protein concentrations from 100 to 150 mg/ml. Crystals were obtained by vapor-diffusion or batch-crystallization methods. The protein crystallized in two morphologies with an apparent morphology dependence on temperature and protein concentration. In general, tetragonal crystals could be grown by lowering the protein concentration or temperature. Increasing the temperature or protein concentration resulted in the growth of orthorhombic crystals. Representative crystals of each morphology were selected for X-ray analysis. The tetragonal crystals belonged to the P4(sub 3)2(sub 1)2 space group with crystals grown at ph 4.4 having unit-cell dimensions of a = b = 78.7 1, c=38.6 A and diffracting to beyond 2.0 A. The orthorhombic crystals, grown at pH 4.8, were of space group P2(sub 1)2(sub 1)2 and had unit-cell dimensions of a = 30.51, b = 56.51 and c = 73.62 A.
21 CFR 880.2200 - Liquid crystal forehead temperature strip.
Code of Federal Regulations, 2010 CFR
2010-04-01
... color changes of heat sensitive liquid crystals corresponding to the variation in the surface temperature of the skin. The liquid crystals, which are cholesteric esters, are sealed in plastic. (b...
21 CFR 880.2200 - Liquid crystal forehead temperature strip.
Code of Federal Regulations, 2013 CFR
2013-04-01
... color changes of heat sensitive liquid crystals corresponding to the variation in the surface temperature of the skin. The liquid crystals, which are cholesteric esters, are sealed in plastic. (b...
21 CFR 880.2200 - Liquid crystal forehead temperature strip.
Code of Federal Regulations, 2011 CFR
2011-04-01
... color changes of heat sensitive liquid crystals corresponding to the variation in the surface temperature of the skin. The liquid crystals, which are cholesteric esters, are sealed in plastic. (b...
21 CFR 880.2200 - Liquid crystal forehead temperature strip.
Code of Federal Regulations, 2012 CFR
2012-04-01
... color changes of heat sensitive liquid crystals corresponding to the variation in the surface temperature of the skin. The liquid crystals, which are cholesteric esters, are sealed in plastic. (b...
21 CFR 880.2200 - Liquid crystal forehead temperature strip.
Code of Federal Regulations, 2014 CFR
2014-04-01
... color changes of heat sensitive liquid crystals corresponding to the variation in the surface temperature of the skin. The liquid crystals, which are cholesteric esters, are sealed in plastic. (b...
Shear induced structures in crystallizing cocoa butter
NASA Astrophysics Data System (ADS)
Mazzanti, Gianfranco; Guthrie, Sarah E.; Sirota, Eric B.; Marangoni, Alejandro G.; Idziak, Stefan H. J.
2004-03-01
Cocoa butter is the main structural component of chocolate and many cosmetics. It crystallizes in several polymorphs, called phases I to VI. We used Synchrotron X-ray diffraction to study the effect of shear on its crystallization. A previously unreported phase (phase X) was found and a crystallization path through phase IV under shear was observed. Samples were crystallized under shear from the melt in temperature controlled Couette cells, at final crystallization temperatures of 17.5^oC, 20^oC and 22.5^oC in Beamline X10A of NSLS. The formation of phase X was observed at low shear rates (90 s-1) and low crystallization temperature (17.5^oC), but was absent at high shear (720 s-1) and high temperature (20^oC). The d-spacing and melting point suggest that this new phase is a mixture rich on two of the three major components of cocoa butter. We also found that, contrary to previous reports, the transition from phase II to phase V can happen through the intermediate phase IV, at high shear rates and temperature.
Shin, Yeonwoo; Kim, Sang Tae; Kim, Kuntae; Kim, Mi Young; Oh, Saeroonter; Jeong, Jae Kyeong
2017-09-07
High-mobility indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) are achieved through low-temperature crystallization enabled via a reaction with a transition metal catalytic layer. For conventional amorphous IGZO TFTs, the active layer crystallizes at thermal annealing temperatures of 600 °C or higher, which is not suitable for displays using a glass substrate. The crystallization temperature is reduced when in contact with a Ta layer, where partial crystallization at the IGZO back-channel occurs with annealing at 300 °C, while complete crystallization of the active layer occurs at 400 °C. The field-effect mobility is significantly boosted to 54.0 cm 2 /V·s for the IGZO device with a metal-induced polycrystalline channel formed at 300 °C compared to 18.1 cm 2 /V·s for an amorphous IGZO TFT without a catalytic layer. This work proposes a facile and effective route to enhance device performance by crystallizing the IGZO layer with standard annealing temperatures, without the introduction of expensive laser irradiation processes.
Shah, Anu; Xia, Ling; Goldberg, Howard; Lee, Ken W.; Quaggin, Susan E.; Fantus, I. George
2013-01-01
Thioredoxin-interacting protein (TxNIP) is up-regulated by high glucose and is associated with oxidative stress. It has been implicated in hyperglycemia-induced β-cell dysfunction and apoptosis. As high glucose and oxidative stress mediate diabetic nephropathy (DN), the contribution of TxNIP was investigated in renal mesangial cell reactive oxygen species (ROS) generation and collagen synthesis. To determine the role of TxNIP, mouse mesangial cells (MC) cultured from wild-type C3H and TxNIP-deficient Hcb-19 mice were incubated in HG. Confocal microscopy was used to measure total and mitochondrial ROS production (DCF and MitoSOX) and collagen IV. Trx and NADPH oxidase activities were assayed and NADPH oxidase isoforms, Nox2 and Nox4, and antioxidant enzymes were determined by immunoblotting. C3H MC exposed to HG elicited a significant increase in cellular and mitochondrial ROS as well as Nox4 protein expression and NADPH oxidase activation, whereas Hcb-19 MC showed no response. Trx activity was attenuated by HG only in C3H MC. These defects in Hcb-19 MC were not due to increased antioxidant enzymes or scavenging of ROS, but associated with decreased ROS generation. Adenovirus-mediated overexpression of TxNIP in Hcb-19 MC and TxNIP knockdown with siRNA in C3H confirmed the specific role of TxNIP. Collagen IV accumulation in HG was markedly reduced in Hcb-19 cells. TxNIP is a critical component of the HG-ROS signaling pathway, required for the induction of mitochondrial and total cell ROS and the NADPH oxidase isoform, Nox4. TxNIP is a potential target to prevent DN. PMID:23329835
Two Decades of Lung Retransplantation: A Single-Center Experience.
Hall, David J; Belli, Erol V; Gregg, Jon A; Salgado, Juan C; Baz, Maher A; Staples, E Denmark; Beaver, Thomas M; Machuca, Tiago N
2017-04-01
Lung retransplantation (ReTx) comprises an increasing share of lung transplants and recently has shown improved outcomes. The aim of this study was to identify risk factors affecting overall survival after pulmonary ReTx. The United Network for Organ Sharing database was used to identify patients undergoing lung transplantation at our institution from 1995 to 2014. Of the total 542 lung transplants performed, 87 (16.1%) were ReTxs. The primary outcome was overall survival. Multivariate Cox regression models were used to assess the effect of recipient and donor characteristics on survival. Of the patients who underwent ReTx, median survival was 2 years. Predictors of worse survival include recipient age between 50 and 60 years (relative risk, 4.3; p = 0.02) or older than 60 years (relative risk, 10.2; p < 0.001), and time to ReTx of less than 2 years (relative risk, 3.8; p = 0.01). ReTx for bronchiolitis obliterans syndrome had longer median survival than for restrictive chronic lung allograft dysfunction (2.7 years vs 0.9 years; p = 0.055). Overall survival of ReTx patients after initiation of the lung allocation score was not significantly different (p = 0.21). Lung ReTx outcomes are significantly worse than for primary transplantation but may be appropriate in well-selected patients with certain diagnoses. Lung ReTx in patients older than 50 years or within 2 years of primary lung transplantation was associated with decreased survival. Further work is warranted to identify patients who benefit most from ReTx. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
Ekström, Klas; Carlsson-Skwirut, Christine; Ritzén, E Martin; Bang, Peter
2011-01-01
Growth hormone insensitivity syndrome (GHIS) is caused by a defective growth hormone receptor (GHR) and is associated with insulin-like growth factor-I (IGF-I) deficiency, severely short stature and, from adolescence, fasting hyperglycemia and obesity. We studied the effects of treatment with IGF-I in either a 1:1 molar complex with IGFBP-3 (IGF-I/BP-3-Tx) or with IGF-I alone (IGF-I-Tx) on metabolism and linear growth. Two brothers, compound heterozygous for a GHR gene defect, were studied. After 8 months without treatment, we examined the short- and long-term effects of IGF-I/BP-3-Tx and, subsequently, IGF-I-Tx on 12-hour overnight levels of IGF-I, GH, insulin, IGFBP-1, insulin sensitivity by hyperinsulinemic euglycemic clamp, body composition by dual-energy X-ray absorptiometry and linear growth. Mean overnight levels of insulin decreased and IGFBP-1, a measure of hepatic insulin sensitivity, increased on both regimens, but was more pronounced on IGF-I-Tx. Insulin sensitivity by clamp showed no consistent changes. Lean body mass increased and abdominal fat mass decreased in both subjects on IGF-I-Tx. However, the changes were inconsistent during IGF-I/BP-3-Tx. Height velocity was low without treatment, increased slightly on IGF-I/BP-3-Tx and doubled on IGF-I-Tx. Both modalities of IGF-I improved determinants of hepatic insulin sensitivity, body composition and linear growth rate; however, IGF-I alone seemed to be more efficient. Copyright © 2011 S. Karger AG, Basel.
A Randomized Trial of an Avatar-Hosted Multiple Behavior Change Intervention for Young Adult Smokers
2013-01-01
Background Young adulthood is a critical transition period for the development of health behaviors. We present here the results of a randomized controlled trial of an online avatar-hosted personal health makeover program designed for young adult smokers. Methods We conducted a three-group randomized trial comparing delivery of general lifestyle content (Tx1), personally tailored health information (Tx2), and personally tailored health information plus online video–based peer coaching (Tx3) as part of a 6-week online health program. Participants were asked to set weekly goals around eating breakfast, exercise, alcohol use, and cigarette smoking. Eligibility criteria included age (18–30 years) and smoking status (any cigarette use in the previous 30 days). The primary outcome was self-reported 30-day abstinence measured 12 weeks postenrollment. Results Participant (n = 1698) characteristics were balanced across the groups (72% women, mean age 24, 26% nonwhite, 32% high school education or less, and 50% daily smokers). Considering intention to treat, 30-day smoking abstinence rates were statistically significantly higher in the intervention groups (Tx1 = 11%, Tx2 = 23%, Tx3 = 31%, P < .001). Participants in the intervention groups were also more likely to reduce their number of days spent on binge drinking and increase their number of days eating breakfast and exercising. Overall, intervention group participants were much more likely to make positive changes in at least three or four of the target behaviors (Tx1 = 19%, Tx2 = 39%, Tx3 = 41%, P < .001). Conclusions This online avatar-hosted personal health makeover “show” increased smoking abstinence and induced positive changes in multiple related health behaviors. Addition of the online video–based peer coaching further improved behavioral outcomes. PMID:24395994
An, Lawrence C; Demers, Michele R S; Kirch, Matthias A; Considine-Dunn, Shannon; Nair, Vijay; Dasgupta, Kohinoor; Narisetty, Naveen; Resnicow, Ken; Ahluwalia, Jasjit
2013-12-01
Young adulthood is a critical transition period for the development of health behaviors. We present here the results of a randomized controlled trial of an online avatar-hosted personal health makeover program designed for young adult smokers. We conducted a three-group randomized trial comparing delivery of general lifestyle content (Tx1), personally tailored health information (Tx2), and personally tailored health information plus online video-based peer coaching (Tx3) as part of a 6-week online health program. Participants were asked to set weekly goals around eating breakfast, exercise, alcohol use, and cigarette smoking. Eligibility criteria included age (18-30 years) and smoking status (any cigarette use in the previous 30 days). The primary outcome was self-reported 30-day abstinence measured 12 weeks postenrollment. Participant (n = 1698) characteristics were balanced across the groups (72% women, mean age 24, 26% nonwhite, 32% high school education or less, and 50% daily smokers). Considering intention to treat, 30-day smoking abstinence rates were statistically significantly higher in the intervention groups (Tx1 = 11%, Tx2 = 23%, Tx3 = 31%, P < .001). Participants in the intervention groups were also more likely to reduce their number of days spent on binge drinking and increase their number of days eating breakfast and exercising. Overall, intervention group participants were much more likely to make positive changes in at least three or four of the target behaviors (Tx1 = 19%, Tx2 = 39%, Tx3 = 41%, P < .001). This online avatar-hosted personal health makeover "show" increased smoking abstinence and induced positive changes in multiple related health behaviors. Addition of the online video-based peer coaching further improved behavioral outcomes.
Azuma, H; Sekizaki, S; Satoh, A; Nakajima, T
1986-05-01
The pharmacological mechanisms of platelet aggregation induced by highly toxic proteins (CrTX-I, CrTX-II, and CrTX-III) obtained from tentacles of a jellyfish, Carybdea rastonii, were investigated. When the partially purified toxin (pCrTX) and CrTXs were added to the citrated platelet-rich plasma (PRP), aggregation was produced in a concentration-dependent manner. The activity of CrTXs was approximately 100 times more potent than pCrTX. The CrTXs-induced aggregation was little affected by indomethacin and quinacrine at concentrations sufficient to inhibit arachidonic acid- and collagen-induced aggregation. The CrTXs-induced aggregation in washed platelets was significantly augmented in the presence of Ca2+. The pretreatment with verapamil failed to modify this augmentation of aggregation. The concentration of cytoplasmic-free calcium ([Ca2+]i) of platelets was increased by CrTXs at the same concentrations that produced aggregation. This effect of CrTXs was again little affected by verapamil. CrTXs at the same concentrations as those that produced aggregation and increased [Ca2+]i caused depolarization of platelets, which was unchanged after pretreatment with sodium or potassium transport inhibitors. CrTX-I significantly increased the 22Na flux into platelets and this effect of CrTX-I was unaffected by tetrodotoxin. The CrTX-I-induced aggregation, depolarization, and increase in [Ca2+]i were all significantly attenuated in the low Na+ medium. These results suggest that CrTXs cause a massive depolarization by increasing cation permeability and this generalized depolarization permits an inward movement of Ca2+ down its electrochemical gradient which, in turn, triggers platelet aggregation.
Olson, Sara N.; Ritter, Kimberley B.; Herb, Dustin W.; Karlen, Steven D.; Lu, Fachuang; Ralph, John; Rooney, William L.; Mullet, John E.
2018-01-01
This study was conducted to document the extent and basis of compositional variation of shoot biomass of the energy Sorghum bicolor hybrid TX08001 during development under field conditions. TX08001 is capable of accumulating ~40 Mg/ha of dry biomass under good growing conditions and this genotype allocates ~80% of its shoot biomass to stems. After 150 days of growth TX08001 stems had a fresh/dry weight ratio of ~3:1 and soluble biomass accounted for ~30% of stem biomass. A panel of diverse energy sorghum genotypes varied ~6-fold in the ratio of stem structural to soluble biomass after 150 days of growth. Near-infrared spectroscopic analysis (NIRS) showed that TX08001 leaves accumulated higher levels of protein, water extractives and ash compared to stems, which have higher sugar, cellulose, and lignin contents. TX08001 stem sucrose content varied during development, whereas the composition of TX08001 stem cell walls, which consisted of ~45–49% cellulose, ~27–30% xylan, and ~15–18% lignin, remained constant after 90 days post emergence until the end of the growing season (180 days). TX08001 and Della stem syringyl (S)/guaiacyl (G) (0.53–0.58) and ferulic acid (FA)/para-coumaric acid (pCA) ratios were similar whereas ratios of pCA/(S+G) differed between these genotypes. Additionally, an analysis of irrigated versus non-irrigated TX08001 revealed that non-irrigated hybrids exhibited a 50% reduction in total cell wall biomass, an ~2-fold increase in stem sugars, and an ~25% increase in water extractives relative to irrigated hybrids. This study provides a baseline of information to help guide further optimization of energy sorghum composition for various end-uses. PMID:29684037
Establishment and Discontinuance Criteria for Airport Traffic Control Towers.
1983-08-01
AR ASW 1 0.74 0.70 -539. HOT MINOT ND AOL 1 0.74 0.72 -509. LRD LAREDO TX ASW 1 0.76 0.72 -492. TXK TEXARKANA AR ASW 1 0.91 0.74 -462. FCN FRESNO CA...SFZ SMITHFIELD RI ANE 0 0.44 0.28 -2270. $IV AURORA CO ANN 0 0.40 0.25 -2387. ORO DURANGO CO ANN 0 0.49 0.43 -1791. 48V ERIE CO ANN 0 0.51 0.36 - 2017 ... 2017 . F70 FORT WORTH TX ASH 0 0.62 0.46 -1713. GLS GALVESTON TX ASW 0 0.83 0.69 -988. F67 GRAND PRAIRIE TX ASH 0 0.75 0.55 -1434. "Do HONDO TX ASW 0 1.77
Defect chemistry and characterization of Hg(1-x)Cd(x)Te
NASA Technical Reports Server (NTRS)
Vydyanath, H. R.
1981-01-01
Undoped mercury cadmium telluride crystals were subjected to high temperature equilibration at temperatures ranging from 400 C to 655 C in various Hg atmospheres. Hall effect and mobility measurements were carried out on the crystals quenched to room temperature subsequent to the high temperature equilibration. The variation of the hole concentration in the cooled crystals at 77 K as a function of the partial pressure of Hg at the equlibration temperatures, together with a comparison of the hole mobility in the undoped samples with that in the copper and phosphorous doped samples yielded a defect model for the undoped crystals, according to which, the undoped crystals are essentially intrinsic at the equilibration temperatures and the native acceptor defects are doubly ionized. Native donor defects appear to be negligible in concentration, implying that the p to n conversion in these alloys is mainly due to residual foreign donor impurities. The thermodynamic constants for the intrinsic excitation process as well as for the incorporation of the doubly ionized native acceptor defects in the undoped crystals were obtained.
NASA Technical Reports Server (NTRS)
Patterson, Richard L.; Hammoud, Ahmad
2011-01-01
Data acquisition and control systems depend on timing signals for proper operation and required accuracy. These clocked signals are typically provided by some form of an oscillator set to produce a repetitive, defined signal at a given frequency. Crystal oscillators are commonly used because they are less expensive, smaller, and more reliable than other types of oscillators. Because of the inherent characteristics of the crystal, the oscillators exhibit excellent frequency stability within the specified range of operational temperature. In some cases, however, some compensation techniques are adopted to further improve the thermal stability of a crystal oscillator. Very limited data exist on the performance and reliability of commercial-off-the-shelf (COTS) crystal oscillators at temperatures beyond the manufacturer's specified operating temperature range. This information is very crucial if any of these parts were to be used in circuits designed for use in space exploration missions where extreme temperature swings and thermal cycling are encountered. This report presents the results of the work obtained on the operation of Silicon Laboratories crystal oscillator, type Si530, under specified and extreme ambient temperatures.
Characterizing the Seasonality and Spatiotemporal Evolution of the U.S. Warming Hole
NASA Astrophysics Data System (ADS)
Partridge, T.; Winter, J.; Osterberg, E. C.; Magilligan, F. J.; Hyndman, D. W.; Kendall, A. D.
2017-12-01
Regions of the Eastern United States have experienced periods of cooling during the last half of the twentieth century inconsistent with broader global warming trends. While there have been a variety of mechanisms proposed to explain this "warming hole", the spatial and temporal definitions of the warming hole often differ across studies, potentially obfuscating the physical drivers leading to its existence. Further, a broad consensus on the causality of the warming hole has yet to be reached. We use daily temperature data from the Global Historical Climate Network (GHCN) to conduct a thorough characterization of the spatiotemporal evolution and seasonality of regional cooling across the Eastern U.S., and define a dynamic warming hole as the region of most persistent cooling. We find that the location of the dynamic warming hole varies by season from the Midwestern U.S. during summer to the Southeastern U.S. during winter. In addition, the cool period associated with the warming hole is characterized by an abrupt decrease in maximum temperature (Tx) and a decline in minimum temperature (Tn) around 1957. While average Tn values in the warming hole recover after the decline and increase from the mid 1960's to present, Tx values for the second half of the 20th century remain below observed values from the first half of the century. To explore large-scale atmospheric drivers of the dynamic warming hole, we correlate SST teleconnection and regional atmospheric circulation indices with seasonal temperature values from 1901-1957 and 1958-2015. We show that 1957 marks a shift, where winter temperatures in the warming hole become more correlated with the Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) and less correlated with the Atlantic Multidecadal Oscillation (AMO). Summer warming hole temperatures become less correlated with the NAO post 1957 and are strongly negatively correlated with precipitation.
History dependent crystallization of Zr{sub 41}Ti{sub 14}Cu{sub 12}Ni{sub 10}Be{sub 23} melts
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schroers, Jan; Johnson, William L.
The crystallization of Zr{sub 41}Ti{sub 14}Cu{sub 12}Ni{sub 10}Be{sub 23} (Vit 1) melts during constant heating is investigated. (Vit 1) melts are cooled with different rates into the amorphous state and the crystallization temperature upon subsequent heating is studied. In addition, Vit 1 melts are cooled using a constant rate to different temperatures and subsequently heated from this temperature with a constant rate. We investigate the influence of the temperature to which the melt was cooled on the crystallization temperature measured upon heating. In both cases the onset temperature of crystallization shows strong history dependence. This can be explained by anmore » accumulating process during cooling and heating. An attempt is made to consider this process in a simple model by steady state nucleation and subsequent growth of the nuclei which results in different crystallization kinetics during cooling or heating. Calculations show qualitative agreement with the experimental results. However, calculated and experimental results differ quantitatively. This difference can be explained by a decomposition process leading to a nonsteady nucleation rate which continuously increases with decreasing temperature. (c) 2000 American Institute of Physics.« less
DOT National Transportation Integrated Search
2011-02-01
This report summarizes the work performed in Fiscal Year (FY) 2009 and 2010 under TxDOT : Implementation Project 5-5541-01 Regional Workshops on Sustainability Enhancement : Tool. TxDOT Research Project 0-5541, Developing Sustainable Tra...
MmTX1 and MmTX2 from coral snake venom potently modulate GABAA receptor activity.
Rosso, Jean-Pierre; Schwarz, Jürgen R; Diaz-Bustamante, Marcelo; Céard, Brigitte; Gutiérrez, José M; Kneussel, Matthias; Pongs, Olaf; Bosmans, Frank; Bougis, Pierre E
2015-02-24
GABAA receptors shape synaptic transmission by modulating Cl(-) conductance across the cell membrane. Remarkably, animal toxins that specifically target GABAA receptors have not been identified. Here, we report the discovery of micrurotoxin1 (MmTX1) and MmTX2, two toxins present in Costa Rican coral snake venom that tightly bind to GABAA receptors at subnanomolar concentrations. Studies with recombinant and synthetic toxin variants on hippocampal neurons and cells expressing common receptor compositions suggest that MmTX1 and MmTX2 allosterically increase GABAA receptor susceptibility to agonist, thereby potentiating receptor opening as well as desensitization, possibly by interacting with the α(+)/β(-) interface. Moreover, hippocampal neuron excitability measurements reveal toxin-induced transitory network inhibition, followed by an increase in spontaneous activity. In concert, toxin injections into mouse brain result in reduced basal activity between intense seizures. Altogether, we characterized two animal toxins that enhance GABAA receptor sensitivity to agonist, thereby establishing a previously unidentified class of tools to study this receptor family.
Emms, H.; Lewis, G. P.
1986-01-01
The effects of aspirin, carboxyheptylimidazole (CHI) and creatine phosphate/creatine phosphokinase (CP/CPK) on platelet aggregation and thromboxane B2 (TxB2) formation induced by collagen have been examined in vitro. Platelets from two species, man and the rat, have been used. In man, aspirin and CHI abolished TxB2 production but only partially inhibited aggregation. CP/CPK partially inhibited aggregation and TxB2 formation. In the rat, aspirin and CHI abolished TxB2 formation but had no effect on aggregation. CP/CPK completely inhibited aggregation and partially inhibited TxB2 generation. In man, collagen-induced aggregation is largely dependent on ADP and to a lesser extent on arachidonate metabolites whereas, in the rat, ADP alone mediates aggregation induced by this agonist. The results with CP/CPK suggest that TxB2 formation is dependent either on the prior release of platelet ADP or on aggregation itself rather than being responsible for the aggregation response. PMID:3082399
NASA Astrophysics Data System (ADS)
AMI Consortium; Rodríguez-Gonzálvez, Carmen; Shimwell, Timothy W.; Davies, Matthew L.; Feroz, Farhan; Franzen, Thomas M. O.; Grainge, Keith J. B.; Hobson, Michael P.; Hurley-Walker, Natasha; Lasenby, Anthony N.; Olamaie, Malak; Pooley, Guy; Saunders, Richard D. E.; Scaife, Anna M. M.; Schammel, Michel P.; Scott, Paul F.; Titterington, David J.; Waldram, Elizabeth M.
2012-09-01
We present detailed 16-GHz interferometric observations using the Arcminute Microkelvin Imager (AMI) of 19 clusters with LX > 7 × 1037 W (h50 = 1) selected from the Local Cluster Substructure Survey (LoCuSS; 0.142 ≤ z ≤ 0.295) and of Abell 1758b, which is in the field of view of Abell 1758a. We detect and resolve Sunyaev-Zel'dovich (SZ) signals towards 17 clusters, with peak surface brightnesses between 5σ and 23σ. We use a fast, Bayesian cluster analysis to obtain cluster parameter estimates in the presence of radio point sources, receiver noise and primordial cosmic microwave background (CMB) anisotropy. We fit isothermal β-models to our data and assume the clusters are virialized (with all the kinetic energy in gas internal energy). Our gas temperature, TAMI, is derived from AMI SZ data and not from X-ray spectroscopy. Cluster parameters internal to r500 are derived under the assumption of hydrostatic equilibrium. We find the following. (i) Different generalized Navarro-Frenk-White (gNFW) parametrizations yield significantly different parameter degeneracies. (ii) For h70 = 1, we find the classical virial radius, r200, to be typically 1.6 ± 0.1 Mpc and the total mass MT(r200) typically to be 2.0-2.5× MT(r500). (iii) Where we have found MT(r500) and MT(r200) X-ray and weak-lensing values in the literature, there is good agreement between weak-lensing and AMI estimates (with MT, AMI/MT, WL =1.2-0.3+0.2 and 1.0 ± 0.1 for r500 and r200, respectively). In comparison, most Suzaku/Chandra estimates are higher than for AMI (with MT, X/MT, AMI = 1.7 ± 0.2 within r500), particularly for the stronger mergers. (iv) Comparison of TAMI to TX sheds light on high X-ray masses: even at large radius, TX can substantially exceed TAMI in mergers. The use of these higher TX values will give higher X-ray masses. We stress that large-radius TAMI and TX data are scarce and must be increased. (v) Despite the paucity of data, there is an indication of a relation between merger activity and SZ ellipticity. (vi) At small radius (but away from any cooling flow) the SZ signal (and TAMI) is less sensitive to intracluster medium disturbance than the X-ray signal (and TX) and, even at high radius, mergers affect n2-weighted X-ray data more than n-weighted SZ, implying that significant shocking or clumping or both occur in even the outer parts of mergers. We request that any reference to this paper cites 'AMI Consortium: Rodríguez-Gonzálvez et al. 2012'.
NASA Astrophysics Data System (ADS)
Kozankiewicz, B.; Prochorow, J.
1989-08-01
Fluorescence, phosphorescence and delayed fluorescence emission characteristics of tetracyanobenzene-hexamethylbenzene (TCNB-HMB) charge-transfer crystal have been studied in the 1.7-340 K temperature range. Delayed fluorescence, originating from heterogeneous triplet-triplet annihilation indicates the presence of mobile charge-transfer triplet excitons at a temperature as low as 1.7 K. However, the behaviour of triplet excitons in TCNB-HMB crystal is strongly controlled by a very efficient trapping process in the whole temperature range investigated. It was found that thermally activated delayed fluorescence, which is a dominating emission of the crystal at elevated temperatures (>60 K), has a different origin (a different initial state) at different temperatures. These observations were analysed and interpreted in terms of a photokinetic model, which is considered to be typical for charge-transfer crystals with high charge-transfer character of triplet excitons.
Synthesis of formamidinium lead iodide perovskite bulk single crystal and its optical properties
NASA Astrophysics Data System (ADS)
Zheng, Hongge; Duan, Junjie; Dai, Jun
2017-07-01
Formamidinium lead iodide (FAPbI3) is a promising hybrid perovskite material for optoelectronic devices. We synthesized bulk single crystal FAPbI3 by a rapid solution crystallization method. X-ray diffraction (XRD) was performed to characterize the crystal structure. Temperature-dependent photoluminescence (PL) spectra of the bulk single crystal FAPbI3 were measured from 10 to 300 K to explain PL recombination mechanism. It shows that near band edge emission blueshifts with the temperature increasing from 10 to 120 K and from 140 K to room temperature, a sudden emission band redshift demonstrates near 140 K because of the phase transition from orthorhombic phase to cubic phase. From the temperature-dependent PL spectra, the temperature coefficients of the bandgap and thermal activation energies of FAPbI3 perovskite are fitted.
Effect of 120 MeV Ag9+ ion irradiation of YCOB single crystals
NASA Astrophysics Data System (ADS)
Arun Kumar, R.; Dhanasekaran, R.
2012-09-01
Single crystals of yttrium calcium oxy borate (YCOB) grown from boron-tri-oxide flux were subjected to swift heavy ion irradiation using silver Ag9+ ions from the 15 UD Pelletron facility at Inter University Accelerator Center, New Delhi. The crystals were irradiated at 1 × 1013, 5 × 1013 and 1 × 1014 ions/cm2 fluences at room temperature and with 5 × 1013 ions/cm2 fluence at liquid nitrogen temperature. The pristine and the irradiated samples were characterized by glancing angle X-ray diffraction, UV-Vis-NIR and photoluminescence studies. From the characterization studies performed on the samples, it is inferred that the crystals irradiated at liquid nitrogen temperature had fewer defects compared to the crystals irradiated at room temperature and the defects increased when the ion fluence was increased at room temperature.
NASA Technical Reports Server (NTRS)
Lal, R. B.
1995-01-01
One of the major objectives of this program was to modify the triglycine sulfate (TGS) crystals with suitable dopants and variants to achieve better pyroelectric properties and improved infrared detectivities (D(sup *)), and higher Curie transition temperature compared to undoped TGS crystals. Towards these objectives, many promising dopants, both inorganic and organic, were investigated in the last few years. These dopants gave significant improvement in the D(sup *) value of the infrared detectors fabricated from the grown crystals with no significant increase in the Curie temperature (49 C). The IR detectors were fabricated at EDO/Barnes Engineering Division, Shelton, CT. In the last one year many TGS crystals doped with urea were grown using the low temperature solution crystal growth facility. It is found that doping with urea, the normalized growth yield increased significantly compared to pure TGS crystals and there is an improvement in the pyroelectric and dielectric constant values of doped crystals. This gave a significant increase in the materials figure of merits. The Vicker's hardness of 10 wt percent urea doped crystals is found to be about three times higher in the (010) direction compared to undoped crystals. This report describes in detail the results of urea doped TGS crystals.
The melt-recrystallization behavior of highly oriented α-iPP fibers embedded in a HIPS matrix.
Ye, Liwei; Li, Huihui; Qiu, Zhaobin; Yan, Shouke
2015-03-21
The melt-recrystallization behavior of α-iPP fibers embedded in an amorphous HIPS matrix has been studied by means of optical microscopy. The amorphous HIPS serving as a supporter of iPP fibers does not become involved in the nucleation and crystallization process of the molten highly oriented iPP fibers. It also does not provide any birefringence under the optical microscope with crossed polarizers. This enables the study of orientation-induced β-iPP crystallization through a control of the melting status of the fibers. Through melting the fibers at different temperatures above 175 °C and subsequent recrystallization, some β-iPP crystals were always produced. The content of the β-iPP crystal depends strongly on the melting temperature and melting time of the iPP fibers. It was confirmed that melting the iPP fibers at relatively lower temperature, e.g. 176 °C, less amount of β-iPP crystals were observed. The content of β-iPP crystal enhances first with increasing melting temperature and then decreases with further increase of the fiber melting temperature. The β-iPP crystallization is found to be most favorable upon melting the fibers at 178 °C for 2 min. This demonstrates the requirement of a certain chain or chain segment orientation for generating β-iPP crystallization on the one hand, while higher orientation of the iPP chains or chain segments encourages the growth of iPP crystals in the α-form on the other hand. This has been further confirmed by varying the melting time of the fiber at different temperatures, since relaxation of the iPP molecular chains at a fixed temperature is time dependent. Moreover, the complete transformation of α-iPP fibers in some local places into β-iPP crystals implies that the αβ-transition may not be required for the orientation-induced β-iPP crystallization.
Forward to cryogenic temperature: laser cooling of Yb: LuLiF crystal
NASA Astrophysics Data System (ADS)
Zhong, Biao; Luo, Hao; Lei, Yongqing; Shi, Yanling; Yin, Jianping
2017-06-01
The high quality Yb-doped fluoride crystals have broad prospects for optical refrigeration. We have laser cooled the Yb:LuLiF crystal to a temperature below the limit of current thermoelectric coolers ( 180 K). The 5% Yb:LuLiF crystal sample has a geometry of 2 mm×2 mm×5 mm and was supported by two fibers of 200 μm in diameter. They were placed in a 2×10-4 Pa vacuum chamber with an environment temperature of 294.5 K. The 1019 nm CW laser of power 38.7 W was adopted to irradiate the sample. The temperature of the sample was measured utilizing the DLT methods. After 20 minutes of laser irradiation, the 5% Yb:LuLiF crystal sample was cooled down to 182.4 K. By further optimizing experimental conditions and increasing the doped Yb concentration, the Yb:LuLiF crystal might be optically cooled below the cryogenic temperature of 123K in the near future.
Local SAR in Parallel Transmission Pulse Design
Lee, Joonsung; Gebhardt, Matthias; Wald, Lawrence L.; Adalsteinsson, Elfar
2011-01-01
The management of local and global power deposition in human subjects (Specific Absorption Rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in conventional single-channel systems and places additional requirements on pTx RF pulse design. We propose a pTx pulse design method which builds on recent work to capture the spatial distribution of local SAR in numerical tissue models in a compressed parameterization in order to incorporate local SAR constraints within computation times that accommodate pTx pulse design during an in vivo MRI scan. Additionally, the algorithm yields a Protocol-specific Ultimate Peak in Local SAR (PUPiL SAR), which is shown to bound the achievable peak local SAR for a given excitation profile fidelity. The performance of the approach was demonstrated using a numerical human head model and a 7T eight-channel transmit array. The method reduced peak local 10g SAR by 14–66% for slice-selective pTx excitations and 2D selective pTx excitations compared to a pTx pulse design constrained only by global SAR. The primary tradeoff incurred for reducing peak local SAR was an increase in global SAR, up to 34% for the evaluated examples, which is favorable in cases where local SAR constraints dominate the pulse applications. PMID:22083594
NASA Astrophysics Data System (ADS)
Zhang, Shujun; Lebrun, Laurent; Randall, Clive A.; Shrout, Thomas R.
2004-06-01
The growth and characterization of (Mn,F) doped Pb(Zn 1/3Nb 2/3)O 3-PbTiO 3 (PZNT) single crystals are reported in this paper. The typical single crystal obtained is up to 30 mm size with dark brown color. The crystal lattice parameters of doped PZNT crystal are slightly decreased compared to the pure one. The room temperature dielectric permittivity along <0 0 1> direction is about 6000, which is lower than that of the pure PZNT8 because of the dopants. The Curie temperature of the doped crystal is about 180°C while the ferroelectric phase transition temperature is around 100°C, which are higher than those of the pure PZNT8 single crystal. The remnant polarization and coercive field of <0 0 1> oriented doped crystal measured at 1 Hz and 10 kV/cm field are about 27 μC/cm 2 and 4.2 kV/cm, respectively. The room temperature mechanical quality factor is ˜300. Piezoelectric coefficient of <0 0 1> oriented doped crystal is higher than 3500 pC/N and the longitudinal electromechanical coupling factor is larger than 93%. The piezoelectric properties of doped PZNT single crystal with temperature and orientations are also reported in this paper. The valence state of the manganese dopant was determined by electron spin resonance, indicating no Mn 4+ in the crystals, suggesting the valence of manganese ions in PZNT crystals may be 2+, which acts as a hardener, stabilizes the domain wall and pins the domain wall motion, on the other hand, the dopant will enter Ti 4+ position, shifting the crystal composition to higher PT content.
Active Control of Interface Shape During the Crystal Growth of Lead Bromide
NASA Technical Reports Server (NTRS)
Duval, W. M. B.; Batur, C.; Singh, N. B.
2003-01-01
A thermal model for predicting and designing the furnace temperature profile was developed and used for the crystal growth of lead bromide. The model gives the ampoule temperature as a function of the furnace temperature, thermal conductivity, heat transfer coefficients, and ampoule dimensions as variable parameters. Crystal interface curvature was derived from the model and it was compared with the predicted curvature for a particular furnace temperature and growth parameters. Large crystals of lead bromide were grown and it was observed that interface shape was in agreement with the shape predicted by this model.
Definition study for temperature control in advanced protein crystal growth
NASA Technical Reports Server (NTRS)
Nyce, Thomas A.; Rosenberger, Franz; Sowers, Jennifer W.; Monaco, Lisa A.
1990-01-01
Some of the technical requirements for an expedient application of temperature control to advanced protein crystal growth activities are defined. Lysozome was used to study the effects of temperature ramping and temperature gradients for nucleation/dissolution and consecutive growth of sizable crystals and, to determine a prototype temperature program. The solubility study was conducted using equine serum albumin (ESA) which is an extremely stable, clinically important protein due to its capability to bind and transport many different small ions and molecules.
78 FR 48298 - Amendment of Class E Airspace; Commerce, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2013-08-08
...-0269; Airspace Docket No. 13-ASW-3] Amendment of Class E Airspace; Commerce, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace at Commerce, TX. Additional controlled airspace is necessary to accommodate new Area Navigation (RNAV...
76 FR 36613 - Environmental Impact Statement; Nueces County, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-06-22
... County, TX AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice of Intent (NOI). SUMMARY... (TxDOT) are issuing this notice to advise the public that an environmental impact statement (EIS) will...--Texas Division, 300 East 8th Street, Austin, Texas 78701. Telephone: 512-536-5960. SUPPLEMENTARY...
76 FR 40598 - Establishment of Class E Airspace; Campbellton, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-07-11
...-1053; Airspace Docket No. 10-ASW-15] Establishment of Class E Airspace; Campbellton, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class E airspace... proposed rulemaking to establish Class E airspace for Campbellton, TX, creating controlled airspace at 74...
76 FR 43822 - Establishment of Class E Airspace; Hearne, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-07-22
...-0214; Airspace Docket No. 11-ASW-2] Establishment of Class E Airspace; Hearne, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class E airspace... notice of proposed rulemaking to establish Class E airspace for Hearne, TX, creating controlled airspace...
77 FR 56761 - Amendment of Class E Airspace; Kerrville, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2012-09-14
...-1399; Airspace Docket No. 11-ASW-14] Amendment of Class E Airspace; Kerrville, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace at... Class E airspace for the Kerrville, TX, area, creating additional controlled airspace at Kerrville...
Role of fluctuations in random compressible systems at marginal dimensionality
NASA Astrophysics Data System (ADS)
Meissner, G.; Sasvári, L.; Tadić, B.
1986-07-01
In a unified treatment we have studied the role of fluctuations in uniaxial random systems at marginal dimensionality d*=4 with the n=1 component order parameter being coupled to elastic degrees of freedom. Depending on the ratio of the nonuniversal parameters of quenched disorder Δ0 and of elastic fluctuations v~0, a first- or second-order phase transition is found to occur, separated by a tricritical point. A complete account of critical properties and of macroscopic as well as of microscopic elastic stability is given for temperatures T>Tc. Universal singularities of thermodynamic functions are determined for t=(T-Tc)/Tc-->0 including the tricritical point: for v~0/Δ0>-2, they are the same as in a rigid random system; for v~0/Δ0=-2, they are different due to lattice compressibility being related, however, to the former by Fisher renormalization. Fluctuation corrections in one-loop approximation have been evaluated in a nonuniversal critical temperature range, tx<
Apparatus for mounting crystal
Longeway, Paul A.
1985-01-01
A thickness monitor useful in deposition or etching reactor systems comprising a crystal-controlled oscillator in which the crystal is deposited or etched to change the frequency of the oscillator. The crystal rests within a thermally conductive metallic housing and arranged to be temperature controlled. Electrode contacts are made to the surface primarily by gravity force such that the crystal is substantially free of stress otherwise induced by high temperature.
Crystal face temperature determination means
Nason, D.O.; Burger, A.
1994-11-22
An optically transparent furnace having a detection apparatus with a pedestal enclosed in an evacuated ampule for growing a crystal thereon is disclosed. Temperature differential is provided by a source heater, a base heater and a cold finger such that material migrates from a polycrystalline source material to grow the crystal. A quartz halogen lamp projects a collimated beam onto the crystal and a reflected beam is analyzed by a double monochromator and photomultiplier detection spectrometer and the detected peak position in the reflected energy spectrum of the reflected beam is interpreted to determine surface temperature of the crystal. 3 figs.
Research on annealing and properties of TlBr crystals for radiation detector use
NASA Astrophysics Data System (ADS)
Zhiping, Zheng; Yongtao, Yu; Dongxiang, Zhou; Shuping, Gong; Qiuyun, Fu
2014-03-01
In this paper, annealing was carried out in air after cutting, polishing and etching to eliminate defects introduced by crystal and wafer preparation work. The effect of annealing temperature and time on the properties of TlBr crystals was investigated. The crystal quality was characterized by infrared (IR) transmittance spectrum, I-V measurement, XRD and energy response spectrum. In the annealing temperature range (100-320 °C) applied, it was found that higher temperature was more effective for improving quality. Furthermore, it is proved that an appropriate annealing time is vital for better crystal quality.
NASA Astrophysics Data System (ADS)
Kovalev, Yu. M.; Kuropatenko, V. F.
2018-05-01
An analysis of the existing approximations used for describing the dependence of heat capacity at a constant volume on the temperature of a molecular crystal has been carried out. It is shown that the considered Debye and Einstein approximations do not enable one to adequately describe the dependence of heat capacity at a constant volume on the temperature of the molecular crystals of nitro compounds. This inference requires the development of special approximations that would describe both low-frequency and high-frequency parts of the vibrational spectra of molecular crystals. This work presents a universal dependence allowing one to describe the dependence of heat capacity at a constant volume on temperature for a number of molecular crystals of nitro compounds.
Growth and characterization of Na2Mo2O7 crystal scintillators for rare event searches
NASA Astrophysics Data System (ADS)
Pandey, Indra Raj; Kim, H. J.; Kim, Y. D.
2017-12-01
Disodium dimolybdate (Na2Mo2O7) crystals were grown using the Czochralski technique. The thermal characteristics of the compound were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The crystal structure of the grown sample was confirmed using X-ray diffraction (XRD). Luminescence properties were measured at room and low temperatures, using a light emitting diode (LED) source. Very weak luminescence was observed at room temperature; however, the luminescence intensity was enhanced at low temperatures. The crystal's transmittance spectrum was measured for estimating its optical quality and energy band gap. The grown crystal exhibited a luminescence light yield of 55% compared with CaMoO4 crystals at 10 K, when excited by a 280-nm-wavelength LED source, but does not have the drawbacks of radioactive Ca isotopes. These results suggest that at cryogenic temperatures, Na2Mo2O7 crystal scintillators are promising for the detection of dark matter and neutrinoless double beta decay of 100Mo.
NASA Astrophysics Data System (ADS)
Price, C. J.
1993-03-01
The distribution of gross imperfections amongst populations of copper sulphate pentahydrate crystals grown under different conditions of purity and temperature are examined. The frequency of imperfection increases with decreasing crystal size. The nature of the imperfections vary with growth temperature and impurities present.
78 FR 52956 - Proposed Flood Hazard Determinations
Federal Register 2010, 2011, 2012, 2013, 2014
2013-08-27
... community may at any time enact stricter requirements of its own, or pursuant to policies established by... City, TX 77662. City of Vidor Public Works Department, 1395 North Main Street, Vidor, TX 77662. City of West Orange City Hall, 2700 Western Avenue, West Orange, TX 77630. Unincorporated Areas of Orange...
78 FR 48294 - Amendment of Class E Airspace; Mason, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2013-08-08
...-1141; Airspace Docket No. 12-ASW-12] Amendment of Class E Airspace; Mason, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace at Mason, TX... Approach Procedures at Mason County Airport. This action enhances the safety and management of Instrument...
75 FR 43886 - Proposed Amendment of Class E Airspace; Corpus Christi, TX
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2010-07-27
...-0404; Airspace Docket No. 10-ASW-7] Proposed Amendment of Class E Airspace; Corpus Christi, TX AGENCY... action proposes to amend Class E airspace in the Corpus Christi, TX area. Additional controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAPs) at Corpus Christi...
75 FR 66301 - Amendment of Class E Airspace; Corpus Christi, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-10-28
... the Corpus Christi, TX, area. Additional controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAP) at Corpus Christi International Airport, Corpus Christi, TX. The FAA is taking this action to enhance the safety and management of Instrument Flight Rule (IFR) operations at the...
76 FR 77245 - Attwater Prairie Chicken National Wildlife Refuge, Austin and Colorado Counties, TX...
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2011-12-12
...-FF02R06000] Attwater Prairie Chicken National Wildlife Refuge, Austin and Colorado Counties, TX..., TX 77434; phone: (979) 234-3021; fax: (979) 234-3278. SUPPLEMENTARY INFORMATION: Introduction With... elements conduct research on of hog movement corridors; impacts of red depending on results of imported...
78 FR 34118 - Endangered Species; Marine Mammals; Receipt of Applications for Permit
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2013-06-06
.... Applicant: Cord Offermann, Austin, TX; PRT-05160B The applicant requests a captive-bred wildlife... Buck Zoo, Gainesville, TX; PRT-06588B The applicant requests a captive-bred wildlife registration under... period. Applicant: KHJ Property Management LLC, Del Rio, TX; PRT-93972A The applicant requests amendment...
75 FR 67806 - Environmental Impact Statement; Nueces County, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-11-03
... County, TX AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Rescind Notice of Intent (NOI) to... Street, Room 826, Austin, Texas 78701, Telephone (512) 536-5960. SUPPLEMENTARY INFORMATION: On April 6, 2007, TxDOT and FHWA announced their revised Notice of Intent to prepare an EIS pursuant to 40 CFR 1508...
75 FR 63533 - Environmental Impact Statement: Cameron County, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-10-15
...: Cameron County, TX AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Rescind Notice of Intent..., 300 East 8th Street, Room 826, Austin, Texas 78701, Telephone (512) 536-5960. SUPPLEMENTARY INFORMATION: On April 6, 2007, TxDOT and FHWA announced their revised Notice of Intent to prepare an EIS...
76 FR 52563 - Special Local Regulations; Sabine River, Orange, TX
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2011-08-23
...-AA08 Special Local Regulations; Sabine River, Orange, TX AGENCY: Coast Guard, DHS. ACTION: Temporary Final rule. SUMMARY: The Coast Guard is establishing a temporary Special Local Regulation on the Sabine River within the Port Arthur, TX Captain of the Port Zone. This Special Local Regulation is intended to...
DOT National Transportation Integrated Search
2009-05-01
The Texas Department of Transportation (TxDOT) uses ramp control signals (also called ramp meters or : flow signals) to control the rate at which vehicles enter the freeway. This helps TxDOT (1) promote a more : consistent and uniform flow of traffic...
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... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [B-76-2012] Foreign-Trade Zone 168--Dallas/Ft. Worth, TX, Authorization of Production Activity, Richemont North America, Inc. dba Cartier (Eyewear Assembly/Kitting), Grand Prairie, TX On October 17, 2012, Metroplex International Trade Development...
76 FR 318 - Designation for the Columbus, OH; Dallas, TX; and Decatur, IN Areas
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2011-01-04
... DEPARTMENT OF AGRICULTURE Grain Inspection, Packers and Stockyards Administration Designation for the Columbus, OH; Dallas, TX; and Decatur, IN Areas AGENCY: Grain Inspection, Packers and Stockyards... Location: Bucyrus, OH. Gulf Country Dallas, TX (214-500-5212)..... 1/1/2011 12/31/2011 Northeast Indiana...
DOT National Transportation Integrated Search
2010-06-18
These slides are intended to be used as a free-standing brief presentation or within larger presentations to describe and promote the advantages of involving TxDOT early in the distribution center site selection process. The purpose is to involve TxD...
2011-12-01
UCMR) data Hockley County, TX (s)Improper Cathodic Protection Elevated Storage Tank 32 TX Lone Star Army Ammunition Plant Texarkana ...River Army Depot Texarkana , TX Propellant Handling Monitoring Well 80 UT Alliant Tech Systems Magna, UT Rocket Manufacturing Public Water Supply Well
77 FR 46282 - Amendment of Class E Airspace; Sweetwater, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-03
...-0829; Airspace Docket No. 11-ASW-9] Amendment of Class E Airspace; Sweetwater, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace at... Register a notice of proposed rulemaking (NPRM) to amend Class E airspace for the Sweetwater, TX, area...
76 FR 43821 - Establishment of Class E Airspace; Ranger, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2011-07-22
...-1240; Airspace Docket No. 10-ASW-18] Establishment of Class E Airspace; Ranger, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class E airspace... Register a notice of proposed rulemaking to establish Class E airspace for Ranger, TX, creating controlled...
78 FR 67296 - Establishment of Class D Airspace; Mesquite, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2013-11-12
...-0580; Airspace Docket No. 12-ASW-2] Establishment of Class D Airspace; Mesquite, TX AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class D airspace... establish Class D airspace for Mesquite Metro Airport, Mesquite, TX (78 FR 48842) Docket No. FAA-2012- 0580...
Impact of simultaneous pancreas-kidney transplantation: patients’ perspectives
Isla Pera, P; Moncho Vasallo, J; Guasch Andreu, O; Ricart Brulles, MJ; Torras Rabasa, A
2012-01-01
Background: Few qualitative studies of simultaneous pancreas-kidney transplantation (SPK Tx) have been published. The aims of this study were to explore from the perspective of patients, the experience of living with diabetes mellitus type 1 (T1DM), suffering from complications, and undergoing SPK Tx with good outcome; and to determine the impact of SPK Tx on patients and their social and cultural environment. Methods: We performed a focused ethnographic study. Twenty patients were interviewed. Data were analyzed using content analysis and constant comparison following the method proposed by Miles and Huberman. Results: A functioning SPK Tx allowed renal replacement therapy and insulin to be discontinued. To describe their new situation, patients used words and phrases such as “miracle”, “being reborn” or “coming back to life”. Although the complications of T1DM, its surgery and treatment, and associated psychological problems did not disappear after SPK Tx, these were minimized when compared with the pretransplantation situation. Conclusion: For patients, SPK Tx represents a recovery of their health and autonomy despite remaining problems associated with the complications of T1DM and SPK Tx. The understanding of patients’ existential framework and their experience of disease are key factors for planning new intervention and improvement strategies. PMID:22936846
Wagner, Nils; Dieteren, Scott; Franz, Niklas; Köhler, Kernt; Mörs, Katharina; Nicin, Luka; Schmidt, Julia; Perl, Mario; Marzi, Ingo; Relja, Borna
2018-01-01
The treatment of patients with multiple trauma including blunt chest/thoracic trauma (TxT) and hemorrhagic shock (H) is still challenging. Numerous studies show detrimental consequences of TxT and HS resulting in strong inflammatory changes, organ injury and mortality. Additionally, the reperfusion (R) phase plays a key role in triggering inflammation and worsening outcome. Ethyl pyruvate (EP), a stable lipophilic ester, has anti-inflammatory properties. Here, the influence of EP on the inflammatory reaction and liver injury in a double hit model of TxT and H/R in rats was explored. Female Lewis rats were subjected to TxT followed by hemorrhage/H (60 min, 35±3 mm Hg) and resuscitation/R (TxT+H/R). Reperfusion was performed by either Ringer`s lactated solution (RL) alone or RL supplemented with EP (50 mg/kg). Sham animals underwent all surgical procedures without TxT+H/R. After 2h, blood and liver tissue were collected for analyses, and survival was assessed after 24h. Resuscitation with EP significantly improved haemoglobin levels and base excess recovery compared with controls after TxT+H/R, respectively (p<0.05). TxT+H/R-induced significant increase in alanine aminotransferase levels and liver injury were attenuated by EP compared with controls (p<0.05). Local inflammation as shown by increased gene expression of IL-6 and ICAM-1, enhanced ICAM-1 and HMGB1 protein expression and infiltration of the liver with neutrophils were also significantly attenuated by EP compared with controls after TxT+H/R (p<0.05). EP significantly reduced TxT+H/R-induced p65 activation in liver tissue. Survival rates improved by EP from 50% to 70% after TxT+H/R. These data support the concept that the pronounced local pro-inflammatory response in the liver after blunt chest trauma and hemorrhagic shock is associated with NF-κB. In particular, the beneficial anti-inflammatory effects of ethyl pyruvate seem to be regulated by the HMGB1/NF-κB axis in the liver, thereby, restraining inflammatory responses and liver injury after double hit trauma in the rat.
Tenenholz, T C; Rogowski, R S; Collins, J H; Blaustein, M P; Weber, D J
1997-03-11
PiTX-K alpha, a 35-residue peptide recently isolated from the venom of Pandinus imperator, blocks the rapidly inactivating (A-type) K+ channel(s) in rat brain synaptosomes and the cloned Kv 1.2 potassium channel at very low toxin concentrations (6 nM and 32 pM, respectively) [Rogowski, R. S., Collins, J. H., O'Neil, T. J., Gustafson, T. A., Werkman, T. A., Rogawski, M. A., Tenenholz, T. C., Weber, D. J., & Blaustein, M. P. (1996) Mol. Pharmacol. 50, 1167-1177]. The three-dimensional structure of PiTX-K alpha was determined using NMR spectroscopy in order to understand its selectivity and affinity toward K+ channels. PiTX-K alpha was found to have an alpha-helix from residues 10 to 21 and two beta-strands (betaI, 26-28; betaII, 33-35) connected by a type II beta-turn to form a small antiparallel beta-sheet. Three disulfide bonds, which are conserved in all members of the charybdotoxin family (alpha-K toxins), anchor one face of the alpha-helix to the beta-sheet. The N-terminal portion of PiTX-K alpha has three fewer residues than other alpha-K toxins such as charybdotoxin. Rather than forming a third beta-strand as found for other alpha-K toxins, the N-terminal region of PiTX-K alpha adopts an extended conformation. This structural difference in PiTX-K alpha together with differences in sequence at Pro-10, Tyr-14, and Asn-25 (versus Ser-10, Trp-14, and Arg-25 in CTX) may explain why PiTX-K alpha does not block maxi-K+ channels. Differences in three-dimensional structure between PiTX-K alpha and charybdotoxin are also observed in both the tight turn and the loop that connects the first beta-strand to the alpha-helix. As a result, side chains of two residues (Tyr-23 and Arg-31) are in regions of PiTX-K alpha that probably interact with rapidly inactivating A-type K+ channels. The analogous residues in charybdotoxin are positioned differently on the toxin surface. Thus, the locations of Tyr-23 and Arg-31 side chains in PiTX-K alpha could explain why this toxin blocks A-type channels at much lower concentrations than does charybdotoxin.
Lyhne-Iversen, Louise; Hobley, Timothy J.; Kaasgaard, Svend G.; Harris, Pernille
2006-01-01
Recombinant Bacillus halmapalus α-amylase (BHA) was studied in two different crystal forms. The first crystal form was obtained by crystallization of BHA at room temperature in the presence of acarbose and maltose; data were collected at cryogenic temperature to a resolution of 1.9 Å. It was found that the crystal belonged to space group P212121, with unit-cell parameters a = 47.0, b = 73.5, c = 151.1 Å. A maltose molecule was observed and found to bind to BHA and previous reports of the binding of a nonasaccharide were confirmed. The second crystal form was obtained by pH-induced crystallization of BHA in a MES–HEPES–boric acid buffer (MHB buffer) at 303 K; the solubility of BHA in MHB has a retrograde temperature dependency and crystallization of BHA was only possible by raising the temperature to at least 298 K. Data were collected at cryogenic temperature to a resolution of 2.0 Å. The crystal belonged to space group P212121, with unit-cell parameters a = 38.6, b = 59.0, c = 209.8 Å. The structure was solved using molecular replacement. The maltose-binding site is described and the two structures are compared. No significant changes were seen in the structure upon binding of the substrates. PMID:16946462
Growth Temperature Dependence of Morphology of GaN Single Crystals in the Na-Li-Ca Flux Method
NASA Astrophysics Data System (ADS)
Wu, Xi; Hao, Hangfei; Li, Zhenrong; Fan, Shiji; Xu, Zhuo
2018-02-01
In this paper, the effect of growth temperature on the morphology and transparency of the GaN crystals obtained by the Li-Ca-added Na Flux method was studied. Addition of Li-Ca was attempted to control the growth habit and further improve transparency of GaN crystals. The samples with wurtzite structure of GaN were confirmed by the x-ray powder diffraction analysis. GaN single crystal with maximum size of about 6 mm was grown at 750°C. As the growth temperature was increased from 700°C to 850°C, the morphology of the crystals changed from pyramid to prism, and their surfaces became smooth. It was found that high growth temperature was beneficial to obtain a transparent crystal, but the evaporation of sodium would suppress its further growth. The E 2 (high) mode in the Raman spectra was at 568 cm-1, and the full-width at half-maximum values of this peak for the crystals obtained at 700°C, 750°C, 800°C, and 850°C were 7.5 cm-1, 10.3 cm-1, 4.4 cm-1, and 4.0 cm-1, respectively. It indicates that all the crystals are stress free and the transparent crystal grown at high temperature has high structural quality or low impurity concentrations.
In-Situ Crystallization of a Lithium Disilicate Glass--Effect of Pressure on Crystal Growth Rate
NASA Technical Reports Server (NTRS)
Fuss, T.; Ray, C. S.; Lesher, C. E.; Day, D. E.
2006-01-01
Crystallization of a Li2O.2SiO2 (LS2) glass subjected to a uniform hydrostatic pressure of 4.5 GPa and 6 GPa was investigated up to a temperature of 750 C. The density of the compressed glass is about 2% greater at 4.5 GPa than at 1 atm and, depending upon the processing temperature, up to 10% greater at 6 GPa. Crystal growth rates investigated as a function of temperature and pressure show that lithium disilicate crystal growth is an order of magnitude slower at 4.5 GPa than 1 atm resulting in a shift of +45 C (plus or minus 10 C) in the growth rate curve at high pressure compared to 1 atm condition. At 6 GPa lithium disilicate crystallization is suppressed entirely, while a new high pressure lithium metasilicate crystallizes at temperatures 95 C (plus or minus 10 C) higher than those reported for lithium disilicate crystallization at 1 atm. The decrease in crystal growth rate with increasing pressure for lithium disilicate glass up to 750 C is related to an increase in viscosity with pressure associated with fundamental changes in glass structure accommodating densification.
A thermally tunable inverse opal photonic crystal for monitoring glass transition.
Sun, Liguo; Xie, Zhuoying; Xu, Hua; Xu, Ming; Han, Guozhi; Wang, Cheng; Bai, Xuduo; Gu, ZhongZe
2012-03-01
An optical method was developed to monitor the glass transition of the polymer by taking advantage of reflection spectrum change of the thermally tunable inverse opal photonic crystal. The thermally tunable photonic bands of the polymer inverse opal photonic crystal were traceable to the segmental motion of macromolecules, and the segmental motion was temperature dependent. By observing the reflection spectrum change of the polystyrene inverse opal photonic crystal during thermal treatment, the glass transition temperature of polystyrene was gotten. Both changes of the position and intensity of the reflection peak were observed during the glass transition process of the polystyrene inverse opal photonic crystal. The optical change of inverse opal photonic crystal was so large that the glass transition temperature could even be estimated by naked eyes. The glass transition temperature derived from this method was consistent with the values measured by differential scanning calorimeter.
NASA Technical Reports Server (NTRS)
Jensen, E. J.; Toon, O. B.
1994-01-01
We have investigated the processes that control ice crystal nucleation in the upper troposphere using a numerical model. Nucleation of ice resulting from cooling was simulated for a range of aerosol number densities, initial temperatures, and cooling rates. In contrast to observations of stratus clouds, we find that the number of ice crystals that nucleate in cirrus is relatively insensitive to the number of aerosols present. The ice crystal size distribution at the end of the nucleation process is unaffected by the assumed initial aerosol number density. Essentially, nucleation continues until enough ice crystals are present such that their deposition growth rapidly depletes the vapor and shuts off any further nucleation. However, the number of ice crystals nucleated increases rapidly with decreasing initial temperature and increasing cooling rate. This temperature dependence alone could explain the large ice crystal number density observed in very cold tropical cirrus.
NASA Astrophysics Data System (ADS)
Yasui, Kyuichi; Mimura, Ken-ichi; Izu, Noriya; Kato, Kazumi
2018-03-01
The dielectric constant of an ordered assembly of BaTiO3 nanocubes is numerically calculated as a function of temperature assuming a distribution of tilt angles of attached nanocubes. As the phase transition temperature from the tetragonal crystal structure to the cubic crystal structure of a BaTiO3 nanocube decreases as the tilt angle increases, the temperature at the peak of the dielectric constant of an ordered assembly is considerably lower than the Curie temperature of a free-standing BaTiO3 crystal. The peak of the dielectric constant as a function of temperature for an ordered assembly becomes considerably broader than that for a single crystal owing to the contribution of nanocubes with various tilt angles.
Nanomodified Carbon/Carbon Composites for Intermediate Temperature
2007-08-31
Carbon nanofibers (CNF) are manufactured by Applied Sciences Inc ./Pyrograf® Products by pyrolytic decomposition of methane in the presence of iron-based...Using PT-30 Resin," Carbon 41 (5), 893 (2003). 7. PT-15 technical data sheet, Lonza Inc ., Fair Lawn, NJ. 8. M. L. Ramirez, et al, Poly. Degrad. & Stab...technical data sheet, Carbon Nanotechnologies, Houston, TX. 32. Advanced SiC NanoPowder technical data sheet, Alpha Materials, Inc ., St. Paul, MN. 33
Mathematical modeling of static layer crystallization for propellant grade hydrogen peroxide
NASA Astrophysics Data System (ADS)
Hao, Lin; Chen, Xinghua; Sun, Yaozhou; Liu, Yangyang; Li, Shuai; Zhang, Mengqian
2017-07-01
Hydrogen peroxide (H2O2) is an important raw material widely used in many fields. In this work a mathematical model of heat conduction with a moving boundary was proposed to study the melt crystallization process of hydrogen peroxide which was carried out outside a cylindrical crystallizer. Considering the effects of the temperature of the cooling fluid on the thermal conductivity of crude crystal, the model is an improvement of Guardani's research and can be solved by analytic iteration method. An experiment was designed to measure the thickness of crystal layer with time under different conditions. A series of analysis, including the effects of different refrigerant temperature on crystal growth rate, the effects of different cooling rates on crystal layer growth rate, the effects of crystallization temperature on heat transfer and the model's application scope were conducted based on the comparison between experimental results and simulation results of the model.
Ni, Xuewen; Ke, Fan; Xiao, Man; Wu, Kao; Kuang, Ying; Corke, Harold; Jiang, Fatang
2016-11-01
Konjac glucomannan (KGM)-based aerogels were prepared using a combination of sol-gel and freeze-drying methods. Preparation conditions were chosen to control ice crystal growth and aerogel structure formation. The ice crystals formed during pre-freezing were observed by low temperature polarizing microscopy, and images of aerogel pores were obtained by scanning electron microscopy. The size of ice crystals were calculated and size distribution maps were drawn, and similarly for aerogel pores. Results showed that ice crystal growth and aerogel pore sizes may be controlled by varying pre-freezing temperatures, KGM concentration and glyceryl monostearate concentration. The impact of pre-freezing temperatures on ice crystal growth was explained as combining ice crystal growth rate with nucleation rate, while the impacts of KGM and glyceryl monostearate concentration on ice crystal growth were interpreted based on their influences on sol network structure. Copyright © 2016 Elsevier B.V. All rights reserved.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Liu, Q; Yan, D
2014-06-01
Purpose: Evaluate the accuracy of atlas-based auto segmentation of organs at risk (OARs) on both helical CT (HCT) and cone beam CT (CBCT) images in head and neck (HN) cancer adaptive radiotherapy (ART). Methods: Six HN patients treated in the ART process were included in this study. For each patient, three images were selected: pretreatment planning CT (PreTx-HCT), in treatment CT for replanning (InTx-HCT) and a CBCT acquired in the same day of the InTx-HCT. Three clinical procedures of auto segmentation and deformable registration performed in the ART process were evaluated: a) auto segmentation on PreTx-HCT using multi-subject atlases, b)more » intra-patient propagation of OARs from PreTx-HCT to InTx-HCT using deformable HCT-to-HCT image registration, and c) intra-patient propagation of OARs from PreTx-HCT to CBCT using deformable CBCT-to-HCT image registration. Seven OARs (brainstem, cord, L/R parotid, L/R submandibular gland and mandible) were manually contoured on PreTx-HCT and InTx-HCT for comparison. In addition, manual contours on InTx-CT were copied on the same day CBCT, and a local region rigid body registration was performed accordingly for each individual OAR. For procedures a) and b), auto contours were compared to manual contours, and for c) auto contours were compared to those rigidly transferred contours on CBCT. Dice similarity coefficients (DSC) and mean surface distances of agreement (MSDA) were calculated for evaluation. Results: For procedure a), the mean DSC/MSDA of most OARs are >80%/±2mm. For intra-patient HCT-to-HCT propagation, the Resultimproved to >85%/±1.5mm. Compared to HCT-to-HCT, the mean DSC for HCT-to-CBCT propagation drops ∼2–3% and MSDA increases ∼0.2mm. This Resultindicates that the inferior imaging quality of CBCT seems only degrade auto propagation performance slightly. Conclusion: Auto segmentation and deformable propagation can generate OAR structures on HCT and CBCT images with clinically acceptable accuracy. Therefore, they can be reliably implemented in the clinical HN ART process.« less
Schmalhofer, William A; Calhoun, Jeffrey; Burrows, Rachel; Bailey, Timothy; Kohler, Martin G; Weinglass, Adam B; Kaczorowski, Gregory J; Garcia, Maria L; Koltzenburg, Martin; Priest, Birgit T
2008-11-01
Voltage-gated sodium (Na(V)1) channels play a critical role in modulating the excitability of sensory neurons, and human genetic evidence points to Na(V)1.7 as an essential contributor to pain signaling. Human loss-of-function mutations in SCN9A, the gene encoding Na(V)1.7, cause channelopathy-associated indifference to pain (CIP), whereas gain-of-function mutations are associated with two inherited painful neuropathies. Although the human genetic data make Na(V)1.7 an attractive target for the development of analgesics, pharmacological proof-of-concept in experimental pain models requires Na(V)1.7-selective channel blockers. Here, we show that the tarantula venom peptide ProTx-II selectively interacts with Na(V)1.7 channels, inhibiting Na(V)1.7 with an IC(50) value of 0.3 nM, compared with IC(50) values of 30 to 150 nM for other heterologously expressed Na(V)1 subtypes. This subtype selectivity was abolished by a point mutation in DIIS3. It is interesting that application of ProTx-II to desheathed cutaneous nerves completely blocked the C-fiber compound action potential at concentrations that had little effect on Abeta-fiber conduction. ProTx-II application had little effect on action potential propagation of the intact nerve, which may explain why ProTx-II was not efficacious in rodent models of acute and inflammatory pain. Mono-iodo-ProTx-II ((125)I-ProTx-II) binds with high affinity (K(d) = 0.3 nM) to recombinant hNa(V)1.7 channels. Binding of (125)I-ProTx-II is insensitive to the presence of other well characterized Na(V)1 channel modulators, suggesting that ProTx-II binds to a novel site, which may be more conducive to conferring subtype selectivity than the site occupied by traditional local anesthetics and anticonvulsants. Thus, the (125)I-ProTx-II binding assay, described here, offers a new tool in the search for novel Na(V)1.7-selective blockers.
Medici, Valentina; Shibata, Noreene M; Kharbanda, Kusum K; Islam, Mohammad S; Keen, Carl L; Kim, Kyoungmi; Tillman, Brittany; French, Samuel W; Halsted, Charles H; LaSalle, Janine M
2014-02-01
Maternal diet can affect fetal gene expression through epigenetic mechanisms. Wilson disease (WD), which is caused by autosomal recessive mutations in ATP7B encoding a biliary copper transporter, is characterized by excessive hepatic copper accumulation, but variability in disease severity. We tested the hypothesis that gestational supply of dietary methyl groups modifies fetal DNA methylation and expression of genes involved in methionine and lipid metabolism that are impaired prior to hepatic steatosis in the toxic milk (tx-j) mouse model of WD. Female C3H control and tx-j mice were fed control (choline 8 mmol/Kg of diet) or choline-supplemented (choline 36 mmol/Kg of diet) diets for 2 weeks throughout mating and pregnancy to gestation day 17. A second group of C3H females, half of which were used to cross foster tx-j pups, received the same diet treatments that extended during lactation to 21 d postpartum. Compared with C3H, fetal tx-j livers had significantly lower copper concentrations and significantly lower transcript levels of Cyclin D1 and genes related to methionine and lipid metabolism. Maternal choline supplementation prevented the transcriptional deficits in fetal tx-j liver for multiple genes related to cell growth and metabolism. Global DNA methylation was increased by 17% in tx-j fetal livers after maternal choline treatment (P<0.05). Maternal dietary choline rescued the lower body weight of 21 d tx-j mice. Our results suggest that WD pathogenesis is modified by maternal in utero factors, including dietary choline.
Medici, Valentina; Shibata, Noreene M; Kharbanda, Kusum K; Islam, Mohammad S; Keen, Carl L; Kim, Kyoungmi; Tillman, Brittany; French, Samuel W; Halsted, Charles H; LaSalle, Janine M
2014-01-01
Maternal diet can affect fetal gene expression through epigenetic mechanisms. Wilson disease (WD), which is caused by autosomal recessive mutations in ATP7B encoding a biliary copper transporter, is characterized by excessive hepatic copper accumulation, but variability in disease severity. We tested the hypothesis that gestational supply of dietary methyl groups modifies fetal DNA methylation and expression of genes involved in methionine and lipid metabolism that are impaired prior to hepatic steatosis in the toxic milk (tx-j) mouse model of WD. Female C3H control and tx-j mice were fed control (choline 8 mmol/Kg of diet) or choline-supplemented (choline 36 mmol/Kg of diet) diets for 2 weeks throughout mating and pregnancy to gestation day 17. A second group of C3H females, half of which were used to cross foster tx-j pups, received the same diet treatments that extended during lactation to 21 d postpartum. Compared with C3H, fetal tx-j livers had significantly lower copper concentrations and significantly lower transcript levels of Cyclin D1 and genes related to methionine and lipid metabolism. Maternal choline supplementation prevented the transcriptional deficits in fetal tx-j liver for multiple genes related to cell growth and metabolism. Global DNA methylation was increased by 17% in tx-j fetal livers after maternal choline treatment (P < 0.05). Maternal dietary choline rescued the lower body weight of 21 d tx-j mice. Our results suggest that WD pathogenesis is modified by maternal in utero factors, including dietary choline. PMID:24220304
Mendieta, Liliana; Granado, Noelia; Aguilera, José; Tizabi, Yousef
2016-01-01
Background: The C-terminal domain of the heavy chain of tetanus toxin (Hc-TeTx) is a nontoxic peptide with demonstrated in vitro and in vivo neuroprotective effects against striatal dopaminergic damage induced by 1-methyl-4-phenylpyridinium and 6-hydoxydopamine, suggesting its possible therapeutic potential in Parkinson’s disease. Methamphetamine, a widely abused psychostimulant, has selective dopaminergic neurotoxicity in rodents, monkeys, and humans. This study was undertaken to determine whether Hc-TeTx might also protect against methamphetamine-induced dopaminergic neurotoxicity and the consequent motor impairment. Methods: For this purpose, we treated mice with a toxic regimen of methamphetamine (4mg/kg, 3 consecutive i.p. injections, 3 hours apart) followed by 3 injections of 40 ug/kg of Hc-TeTx into grastrocnemius muscle at 1, 24, and 48 hours post methamphetamine treatment. Results: We found that Hc-TeTx significantly reduced the loss of dopaminergic markers tyrosine hydroxylase and dopamine transporter and the increases in silver staining (a well stablished degeneration marker) induced by methamphetamine in the striatum. Moreover, Hc-TeTx prevented the increase of neuronal nitric oxide synthase but did not affect microglia activation induced by methamphetamine. Stereological neuronal count in the substantia nigra indicated loss of tyrosine hydroxylase-positive neurons after methamphetamine that was partially prevented by Hc-TeTx. Importantly, impairment in motor behaviors post methamphetamine treatment were significantly reduced by Hc-TeTx. Conclusions: Here we demonstrate that Hc-TeTx can provide significant protection against acute methamphetamine-induced neurotoxicity and motor impairment, suggesting its therapeutic potential in methamphetamine abusers. PMID:26945022
Mumford, Andrew D; Dawood, Ban B; Daly, Martina E; Murden, Sherina L; Williams, Michael D; Protty, Majd B; Spalton, Jennifer C; Wheatley, Mark; Mundell, Stuart J; Watson, Steve P
2010-01-14
We investigated the cause of mild mucocutaneous bleeding in a 14-year-old male patient (P1). Platelet aggregation and ATP secretion induced by arachidonic acid and the thromboxane A(2) receptor (TxA(2)R) agonist U46619 were reduced in P1 compared with controls, whereas the responses to other platelet agonists were retained. P1 was heterozygous for a transversion within the TBXA2R gene predictive of a D304N substitution in the TxA(2)R. In Chinese hamster ovary-K1 cells expressing the variant D304N TxA(2)R, U46619 did not increase cytosolic free Ca(2+) concentration, indicating loss of receptor function. The TxA(2)R antagonist [(3)H]-SQ29548 showed an approximate 50% decrease in binding to platelets from P1 but absent binding to Chinese hamster ovary-K1 cells expressing variant D304N TxA(2)R. This is the second naturally occurring TxA(2)R variant to be associated with platelet dysfunction and the first in which loss of receptor function is associated with reduced ligand binding. D304 lies within a conserved NPXXY motif in transmembrane domain 7 of the TxA(2)R that is a key structural element in family A G protein-coupled receptors. Our demonstration that the D304N substitution causes clinically significant platelet dysfunction by reducing ligand binding establishes the importance of the NPXXY motif for TxA(2)R function in vivo.
Local SAR in parallel transmission pulse design.
Lee, Joonsung; Gebhardt, Matthias; Wald, Lawrence L; Adalsteinsson, Elfar
2012-06-01
The management of local and global power deposition in human subjects (specific absorption rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in conventional single-channel systems and places additional requirements on pTx radio frequency pulse design. We propose a pTx pulse design method which builds on recent work to capture the spatial distribution of local SAR in numerical tissue models in a compressed parameterization in order to incorporate local SAR constraints within computation times that accommodate pTx pulse design during an in vivo magnetic resonance imaging scan. Additionally, the algorithm yields a protocol-specific ultimate peak in local SAR, which is shown to bound the achievable peak local SAR for a given excitation profile fidelity. The performance of the approach was demonstrated using a numerical human head model and a 7 Tesla eight-channel transmit array. The method reduced peak local 10 g SAR by 14-66% for slice-selective pTx excitations and 2D selective pTx excitations compared to a pTx pulse design constrained only by global SAR. The primary tradeoff incurred for reducing peak local SAR was an increase in global SAR, up to 34% for the evaluated examples, which is favorable in cases where local SAR constraints dominate the pulse applications. Copyright © 2011 Wiley Periodicals, Inc.
NASA Astrophysics Data System (ADS)
Hofmann, D. W. M.; Kuleshova, L. N.
2018-05-01
Modern force fields are accurate enough to describe thermal effects in molecular crystals. Here, we have extended our earlier approach to discrete force fields for various temperatures to a force field with a continuous function. For the parametrisation of the force field, we used data mining on experimental structures with the temperature as an additional descriptor. The obtained force field can be used to minimise energy at a finite temperature and for molecular dynamics with zero-K potentials. The applicability of the method has been demonstrated for the prediction of crystal density, temperature density gradients and transition temperature.
Electrical resistivity in Zr48Nb8Cu12Fe8Be24 glassy and crystallized alloys
NASA Astrophysics Data System (ADS)
Bai, H. Y.; Tong, C. Z.; Zheng, P.
2004-02-01
The electrical resistivity of Zr48Nb8Cu12Fe8Be24 bulk metallic glassy and crystallized alloys in the temperature range of 4.2-293 K is investigated. It is found that the resistivity in glassy and crystallized states shows opposite temperature coefficients. For the metallic glass, the resistivity shows a negative logarithmic dependence at temperatures below 16 K, whereas it has more normal behavior for the crystallized alloy. At higher temperatures, the resistivity in both glassy and crystallized alloys shows dependence upon both T and T2, but the signs of the T and T2 terms are opposite. The results are interpreted in terms of scattering from two-level tunneling states in glasses and the generalized Ziman diffraction model.
Stability relationship for water droplet crystallization with the NASA Lewis icing spray
NASA Technical Reports Server (NTRS)
Marek, C. John; Bartlett, C. Scott
1987-01-01
In order to produce small droplets for icing cloud simulation, high pressure air atomizing nozzles are used. For certain icing testing applications, median drop sizes as small as 5 mm are needed, which require air atomizing pressures greater than 3000 kPa. Isentropic expansion of the ambient temperature atomizing air to atmospheric pressure can result in air stream temperatures of -160 C which results in ice crystals forming in the cloud. To avoid such low temperatures, it is necessary to heat the air and water to high initial temperatures. An icing spray research program was conducted to map the temperatures below which ice crystals form. A soot slide technique was used to determine the presence of crystals in the spray.
Filik, Hayati; Sener, Izzet; Cekiç, Sema Demirci; Kiliç, Emine; Apak, Reşat
2006-06-01
In the present paper, conventional spectrophotometry in conjunction with cloud point extraction-preconcentration were investigated as alternative methods for paracetamol (PCT) assay in urine samples. Cloud point extraction (CPE) was employed for the preconcentration of p-aminophenol (PAP) prior to spectrophotometric determination using the non-ionic surfactant Triton X-114 (TX-114) as an extractant. The developed methods were based on acidic hydrolysis of PCT to PAP, which reacted at room temperature with 25,26,27,28-tetrahydroxycalix[4]arene (CAL4) in the presence of an oxidant (KIO(4)) to form an blue colored product. The PAP-CAL4 blue dye formed was subsequently entrapped in the surfactant micelles of Triton X-114. Cloud point phase separation with the aid of Triton X-114 induced by addition of Na(2)SO(4) solution was performed at room temperature as an advantage over other CPE assays requiring elevated temperatures. The 580 nm-absorbance maximum of the formed product was shifted bathochromically to 590 nm with CPE. The working range of 1.5-12 microg ml(-1) achieved by conventional spectrophotometry was reduced down to 0.14-1.5 microg ml(-1) with cloud point extraction, which was lower than those of most literature flow-through assays that also suffer from nonspecific absorption in the UV region. By preconcentrating 10 ml sample solution, a detection limit as low as 40.0 ng ml(-1) was obtained after a single-step extraction, achieving a preconcentration factor of 10. The stoichiometric composition of the dye was found to be 1 : 4 (PAP : CAL4). The impact of a number of parameters such as concentrations of CAL4, KIO(4), Triton X-100 (TX-100), and TX-114, extraction temperature, time periods for incubation and centrifugation, and sample volume were investigated in detail. The determination of PAP in the presence of paracetamol in micellar systems under these conditions is limited. The established procedures were successfully adopted for the determination of PCT in urine samples. Since the drug is rapidly absorbed and excreted largely in urine and its high doses have been associated with lethal hepatic necrosis and renal failure, development of a rapid, sensitive and selective assay of PCT is of vital importance for fast urinary screening and antidote administration before applying more sophisticated, but costly and laborious hyphenated instrumental techniques of HPLC-SPE-NMR-MS.
75 FR 13453 - Proposed Amendment of Class E Airspace; Corpus Christi, TX
Federal Register 2010, 2011, 2012, 2013, 2014
2010-03-22
...-0089; Airspace Docket No. 10-ASW-1] Proposed Amendment of Class E Airspace; Corpus Christi, TX AGENCY... action proposes to amend Class E airspace in the Corpus Christi, TX area. Additional controlled airspace... adding additional Class E airspace extending upward from 700 feet above the surface in the Corpus Christi...
Flight Test Experiments Foreseen for USV
2005-10-01
USA W.T. - Japan W .T. - Australia: ANU ( National University) W .T. - USA: NASA , AEDC, CALTEC, CUBRC W .T. - Japan: NAL 1.0E-05 1.0E-04... reflectometry ”. • Active (TX / RX) / passive (RX only) mode experiments • Main on-board elements: • RX • TX (possibly shared with system TX) • antennas
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2010-05-20
..., Leased Workers from Computer Merchant, LTD, Austin, TX: September 30, 2008. TA-W-72,704B: Starwood Hotels...,446: Genesis Networks Solutions, Inc., Abilene, TX: February 3, 2009. The following certifications... Finance Organization, Leased Workers of Kelly Services, Houston, TX: December 16, 2008. TA-W-73,133: CVG...
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...-0877; Airspace Docket No. 10-ASW-13] Amendment of Class E Airspace; Carizzo Springs, Glass Ranch... amends Class E airspace for the Carizzo Springs, Glass Ranch Airport, TX, airspace area, to accommodate... rulemaking to amend Class E airspace for the Carizzo Springs, Glass Ranch Airport, TX, airspace area...
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... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [B-2-2013] Foreign-Trade Zone 117--Orange, TX, Authorization of Production Activity, Signal International Texas GP, LLC (Shipbuilding), Orange, TX On January 10, 2013, the Foreign Trade Zone of Southeast Texas, Inc., grantee of FTZ 117, submitted a...
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... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL13-45-000] TGP Development Company, LLC; TGP Flying Cloud Holdings, LLC; WEC TX Company, LLC v. Arizona Public Service Company... Cloud Holdings, LLC, and WEC TX Company, LLC (collectively, Complainants) filed a formal complaint...
DOT National Transportation Integrated Search
2017-01-01
Based on the research and input from the private sector, four themes emerged that frame the role of TxDOT in preparing for an efficient, reliable, and safe freight transportation system in 2055: : TxDOT is expected to be a facilitator/manager of ...
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2013-01-18
... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [B-70-2012] Foreign-Trade Zone 265--Conroe, TX; Authorization of Production Activity; Bauer Manufacturing, Inc. (Pile Drivers and Boring Machinery), Conroe, TX On September 12, 2012, the City of Conroe, Texas, grantee of FTZ 20, submitted a notification of...
Dosimetric characteristics of Novalis Tx system with high definition multileaf collimator
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chang Zheng; Wang Zhiheng; Wu, Q. Jackie
A new Novalis Tx system equipped with a high definition multileaf collimator (HDMLC) recently became available to perform both image-guided radiosurgery and conventional radiotherapy. It is capable of delivering a highly conformal radiation dose with three energy modes: 6 MV photon energy, 15 MV photon energy, and 6 MV photon energy in a stereotactic radiosurgery mode with 1000 MU/min dose rate. Dosimetric characteristics of the new Novalis Tx treatment unit with the HDMLC are systematically measured for commissioning. A high resolution diode detector and miniion-chamber detector are used to measure dosimetric data for a range of field sizes from 4x4more » mm to 400x400 mm. The commissioned Novalis Tx system has passed the RPC stereotactic radiosurgery head phantom irradiation test. The Novalis Tx system not only expands its capabilities with three energy modes, but also achieves better beam conformity and sharer beam penumbra with HDMLC. Since there is little beam data information available for the new Novalis Tx system, we present in this work the dosimetric data of the new modality for reference and comparison.« less
Implantable, Ingestible Electronic Thermometer
NASA Technical Reports Server (NTRS)
Kleinberg, Leonard
1987-01-01
Small quartz-crystal-controlled oscillator swallowed or surgically implanted provides continuous monitoring of patient's internal temperature. Receiver placed near patient measures oscillator frequency, and temperature inferred from previously determined variation of frequency with temperature. Frequency of crystal-controlled oscillator varies with temperature. Circuit made very small and implanted or ingested to measure internal body temperature.
Tunable two-dimensional photonic crystals using liquid crystal infiltration
NASA Astrophysics Data System (ADS)
Leonard, S. W.; Mondia, J. P.; van Driel, H. M.; Toader, O.; John, S.; Busch, K.; Birner, A.; Gösele, U.; Lehmann, V.
2000-01-01
The photonic band gap of a two-dimensional photonic crystal is continuously tuned using the temperature dependent refractive index of a liquid crystal. Liquid crystal E7 was infiltrated into the air pores of a macroporous silicon photonic crystal with a triangular lattice pitch of 1.58 μm and a band gap wavelength range of 3.3-5.7 μm. After infiltration, the band gap for the H polarized field shifted dramatically to 4.4-6.0 μm while that of the E-polarized field collapsed. As the sample was heated to the nematic-isotropic phase transition temperature of the liquid crystal (59 °C), the short-wavelength band edge of the H gap shifted by as much as 70 nm while the long-wavelength edge was constant within experimental error. Band structure calculations incorporating the temperature dependence of the liquid crystal birefringence can account for our results and also point to an escaped-radial alignment of the liquid crystal in the nematic phase.
Persistent disorders of mineral metabolism after one year of kidney transplantation.
Gomes, Larissa Kruger; Custódio, Melani Ribeiro; Contieri, Fabiana Loss de Carvalho; Riella, Miguel C; Nascimento, Marcelo Mazza do
2016-01-01
The persistence of mineral metabolism disorders after renal transplant (RT) appears to possess a negative impact over graft and patient's survival. To evaluate the parameters of mineral metabolism and the persistence of hyperparathyroidism (HPT) in transplanted patients for a 12-month period after the procedure. Retrospective analysis of 41 transplants (18 women- 44%, mean age of 39 ± 15 years) performed in a University Hospital, evaluating changes of calcium (Ca), phosphorus (P) and parathyroid hormone (PTH) and the prevalence of persistent HPT. The patients were divided into two groups accordingly to PTH levels prior to Tx: Group 1 with PTH ≤ 300 pg/mL (n = 21) and Group 2 with PTH > 300 pg/mL (n = 20). The persistency of HPT after transplant was defined as PTH ≥ 100 pg/mL. The evolution of biochemical parameters and the persistency of HPT were analyzed in each group after 1 year of transplant. After a one-year of follow up, 5% of the patients presented hypophosphatemia (p < 2.7 mg/dL), 24% hypercalcemia (Ca > 10.2 mg/dL) and 48% persistency of HPT (PTH ≥ 100 pg/mL). There was a positive correlation between the PTH pre and post Tx (r = 0.42/p = 0.006) and a negative correlation between PTH and Ca pre-Tx (r = -0.45/p = 0.002). However, there was no significant difference among groups 1 and 2 regarding PTH levels pre and post Tx. The findings in this article suggest that mineral metabolism alterations and the persistency of HPT may occur after one year of renal Tx, mainly in patients which present high PTH levels prior toTx. A persistência de distúrbios do metabolismo mineral ósseo após o transplante renal (Tx) parece possuir um impacto negativo sobre a sobrevida do enxerto e do paciente. avaliar os parâmetros do metabolismo mineral e a persistência de hiperparatiroidismo (pHPT) 12 meses após o Tx. Análise retrospectiva de 41 transplantes (18 mulheres- 44%, idade de 39 ± 15 anos) realizados em um Hospital Universitário, avaliando cálcio (Ca), fósforo (P), hormônio da paratireóide (PTH) e a prevalência de pHPT. Pacientes foram divididos em dois grupos de acordo com os níveis de PTH pré Tx: Grupo 1: PTH ≤ 300 pg/ml (n = 21) e Grupo 2: PTH > 300 pg/ml (n = 20). pHPT foi definida como PTH ≥ 100pg/mL após o Tx. A evolução dos parâmetros bioquímicos e a pHPT foram analisadas após 1 ano de Tx. Resultados: após um ano, 5% dos pacientes apresentaram hipofosfatemia (p < 2,7mg/dL), 24% hipercalcemia (Ca > 10,2 mg/dL) e 48% persistência de HPT (PTH ≥ 100 pg/mL ). Houve correlação positiva entre PTH pré e pós Tx (r = 0,42/p = 0,006) e correlação negativa entre PTH e Ca pré-Tx (r = -0,45/p = 0,002). Entretanto, não houve diferença significativa entre os grupos 1 e 2 em relação aos níveis de PTH pré e pós-Tx. Os resultados sugerem que alterações do metabolismo mineral e a pHPT podem ocorrer após um ano do Tx, principalmente em pacientes com níveis elevados de PTH pré-Tx.
Viscosity minima in binary mixtures of ionic liquids + molecular solvents.
Tariq, M; Shimizu, K; Esperança, J M S S; Canongia Lopes, J N; Rebelo, L P N
2015-05-28
The viscosity (η) of four binary mixtures (ionic liquids plus molecular solvents, ILs+MSs) was measured in the 283.15 < T/K < 363.15 temperature range. Different IL/MS combinations were selected in such a way that the corresponding η(T) functions exhibit crossover temperatures at which both pure components present identical viscosity values. Consequently, most of the obtained mixture isotherms, η(x), exhibit clear viscosity minima in the studied T-x range. The results are interpreted using auxiliary molecular dynamics (MD) simulation data in order to correlate the observed η(T,x) trends with the interactions in each mixture, including the balance between electrostatic forces and hydrogen bonding.
The crystallization of tough thermoplastic resins in the presence of carbon fibers
NASA Technical Reports Server (NTRS)
Theil, Michael H.
1988-01-01
The presence of carbon fibers increased the crystallization rates of both PEEK and PPS thermoplastic polymers. The effect was most pronounced at higher crystallization temperatures. Isothermal crystallization rates were analyzed by applying classical phenomenological nucleation theory. Unusually high values of the so-called Avrami exponent were found for neat PEEK. Isothermal crystallization of PEEK and PPS polymers produced crystalline samples having a wide variety of melting temperatures. The melting as observed by differential scanning calorimetry occurred as dual endotherms which were called primary (higher temperature) and secondary melting peaks. Each primary peak accounted for most of the crystallinity present. The secondary peaks represented the melting of crystallites formed later than those attributable to the primary endotherms. The presence of carbon fibers increased the thermal stability of both PEEK and PPS crystallites as manifested by higher temperatures for the primary melting peaks. This may be attributable to increased crystallite size, greater crystallite perfection, and/or favorable modification of the crystallite interface. Over the range studied, crystallization temperature strongly influenced the positions of the secondary peaks but not the primary peaks.
Kunze-Szikszay, Nils; Krack, Lennart A; Wildenauer, Pauline; Wand, Saskia; Heyne, Tim; Walliser, Karoline; Spering, Christopher; Bauer, Martin; Quintel, Michael; Roessler, Markus
2016-10-10
Hyperfibrinolysis (HF) is a major contributor to coagulopathy and mortality in trauma patients. This study investigated (i) the rate of HF during the pre-hospital management of patients with multiple injuries and (ii) the effects of pre-hospital tranexamic acid (TxA) administration on the coagulation system. From 27 trauma patients with pre-hospital an estimated injury severity score (ISS) ≥16 points blood was obtained at the scene and on admission to the emergency department (ED). All patients received 1 g of TxA after the first blood sample was taken. Rotational thrombelastometry (ROTEM) was performed for both blood samples, and the results were compared. HF was defined as a maximum lysis (ML) >15 % in EXTEM. The median (min-max) ISS was 17 points (4-50 points). Four patients (15 %) had HF diagnosed via ROTEM at the scene, and 2 patients (7.5 %) had HF diagnosed via ROTEM on admission to the ED. The median ML before TxA administration was 11 % (3-99 %) vs. 10 % after TxA administration (4-18 %; p > 0.05). TxA was administered 37 min (10-85 min) before ED arrival. The ROTEM results before and after TxA administration did not significantly differ. No adverse drug reactions were observed after TxA administration. HF can be present in severely injured patients during pre-hospital care. Antifibrinolytic therapy administered at the scene is a significant time saver. Even in milder trauma fibrinogen can be decreased to critically low levels. Early administration of TxA cannot reverse or entirely stop this decrease. The pre-hospital use of TxA should be considered for severely injured patients to prevent the worsening of trauma-induced coagulopathy and unnecessarily high fibrinogen consumption. ClinicalTrials.gov ID NCT01938768 (Registered 5 September 2013).
Pragl, Bernt; Koschak, Alexandra; Trieb, Maria; Obermair, Gerald; Kaufmann, Walter A; Gerster, Uli; Blanc, Eric; Hahn, Christoph; Prinz, Heino; Schütz, Gerhard; Darbon, Herve; Gruber, Hermann J; Knaus, Hans-Günther
2002-01-01
Hongotoxin(1) (HgTX(1)), a 39-residue peptide recently isolated from the venom of Centruroides limbatus, blocks the voltage-gated K+ channels K(v)1.1, K(v)1.2, and K(v)1.3 at picomolar toxin concentrations (Koschak, A., Bugianesi, R. M., Mitterdorfer, J., Kaczorowski, G. J., Garcia, M. L., and Knaus, H. G. (1998) J. Biol. Chem. 273, 2639-2644). In this report, we determine the three-dimensional structure of HgTX(1) using NMR spectroscopy (PDB-code: 1HLY). HgTX(1) was found to possess a structure similar to previously characterized K+ channel toxins (e.g. margatoxin) consisting of a three-stranded antiparallel beta-sheet (residues 2-4, 26-30, and 33-37) and a helical conformation (part 3(10) helix and part alpha helix; residues 10-20). Due to the importance of residue Lys-28 for high-affinity interaction with the respective channels, lysine-reactive fluorescence dyes cannot be used to label wild-type HgTX(1). On the basis of previous studies (see above) and our NMR data, a HgTX(1) mutant (HgTX(1)-A19C) was engineered, expressed, and purified. HgTX(1)-A19C-SH was labeled using sulfhydryl-reactive Cy3-, Cy5-, and Alexa-dyes. Pharmacological characterization of fluorescently labeled HgTX(1)-A19C in radioligand binding studies indicated that these hongotoxin(1) analogues retain high-affinity for voltage-gated K+ channels and a respective pharmacological profile. Cy3- and Alexa-dye-labeled hongotoxin(1) analogues were used to investigate the localization of K+ channels in brain sections. The distribution of toxin binding closely follows the distribution of K(v)1.2 immunoreactivity with the highest expression levels in the cerebellar Purkinje cell layer. Taken together, these results demonstrate that fluorescently labeled HgTX(1) analogues comprise novel probes to characterize a subset of voltage-gated K+ channels.
Vicari, Enzo; La Vignera, Sandro; Castiglione, Roberto; Condorelli, Rosita A; Vicari, Lucia O; Calogero, Aldo E
2014-01-01
This study was undertaken to evaluate the influence of treatment with rifaximin followed by the probiotic VSL#3 versus no treatment on the progression of chronic prostatitis toward chronic microbial prostate-vesiculitis (PV) or prostate-vesiculo-epididymitis (PVE). A total of 106 selected infertile male patients with bacteriologically cured chronic bacterial prostatitis (CBP) and irritable bowel syndrome (IBS) were randomly prescribed rifaximin (200 mg, 2 tablets bid, for 7 days monthly for 12 months) and probiotic containing multiple strains VSL#3 (450 × 10(9) FU per day) or no treatment. Ninety-five of them (89.6%) complied with the therapeutic plan and were included in this study. Group A = "6Tx/6-": treatment for the initial 6 and no treatment for the following 6 months (n = 26); Group B = "12Tx": 12 months of treatment (n = 22); Group C = "6-/6Tx": no treatment for the initial 6 months and treatment in the last 6 months (n = 23); Group D = "12-": no treatment (n = 24). The patients of Groups A = "6Tx/6-" and B = "12Tx" had the highest frequency of chronic prostatitis (88.5% and 86.4%, respectively). In contrast, group "12-": patients had the lowest frequency of prostatitis (33.4%). The progression of prostatitis into PV in groups "6Tx/6-" (15.5%) and "6-/6Tx" (13.6%) was lower than that found in the patients of group "12-" (45.8%). Finally, no patient of groups "6Tx/6-" and "6-/6Tx" had PVE, whereas it was diagnosed in 20.8% of group "12-" patients. Long-term treatment with rifaximin and the probiotic VSL#3 is effective in lowering the progression of prostatitis into more complicated forms of male accessory gland infections in infertile patients with bacteriologically cured CBP plus IBS.
Temperature-dependent μ-Raman investigation of struvite crystals.
Prywer, Jolanta; Kasprowicz, D; Runka, T
2016-04-05
The effect of temperature on the vibrational properties of struvite crystals grown from silica gels was systematically studied by μ-Raman spectroscopy. The time-dependent Raman spectra recorded in the process of long time annealing of struvite crystal at 353 K do not indicate structural changes in the struvite crystal with the time of annealing. The temperature-dependent Raman spectra recorded in the range 298-423 K reveal a phase transition in struvite at about 368 K. Above this characteristic temperature, some of bands assigned to vibrations of the PO4 and NH4 tetrahedra and water molecules observed in the Raman spectra in low temperatures (orthorhombic phase) change their spectral parameters or disappear, which indicates a transition to a higher symmetry structure of struvite in the range of high temperatures. Copyright © 2016 Elsevier B.V. All rights reserved.
Sargent, P B; Bryan, G K; Streichert, L C; Garrett, E N
1991-11-01
The binding of neuronal bungarotoxin (n-BuTX; also known as bungarotoxin 3.1, kappa-bungarotoxin, and toxin F) was analyzed in normal and denervated parasympathetic cardiac ganglia of the frog Rana pipiens, n-BuTX blocks both EPSPs and ACh potentials at 5-20 nM, as determined by intracellular recording techniques. Scatchard analysis on homogenates indicates that cardiac ganglia have two classes of binding sites for 125I-n-BuTX: a high-affinity site with an apparent dissociation constant (Kd,app) of 1.7 nM and a Bmax (number of binding sites) of 3.8 fmol/ganglion and a low-affinity site with a Kd,app of 12 microM and a Bmax of 14 pmol/ganglion. alpha-Bungarotoxin does not appear to interfere with the binding of 125I-n-BuTX to either site. The high-affinity binding site is likely to be the functional nicotinic ACh receptor (AChR), given the similarity between its affinity for 125I-n-BuTX and the concentration of n-BuTX required to block AChR function. Light microscopic autoradiographic analysis of 125I-n-BuTX binding to the ganglion cell surface reveals that toxin binding is concentrated at synaptic sites, which were identified using a synaptic vesicle-specific antibody. Scatchard analysis of autoradiographic data reveals that 125I-n-BuTX binding to the neuronal surface is saturable and has a Kd,app similar to that of the high-affinity binding site characterized in homogenates. Surface binding of 125I-n-BuTX is blocked by nicotine, carbachol, and d-tubocurarine (IC50 less than 20 microM), but not by atropine (IC50 greater than 10 mM). Denervation of the heart increases the ACh sensitivity of cardiac ganglion cells but has no effect upon the number of high-affinity binding sites for 125I-n-BuTX in tissue homogenates. Moreover, autoradiographic analysis indicates that denervation does not alter the number of 125I-n-BuTX binding sites on the ganglion cell surface. n-BuTX is as effective in reducing ganglion cell responses to ACh in denervated ganglia as it is in normally innervated ganglia. These results suggest that denervation alters neither the total number of nicotinic AChRs in the cardiac ganglion nor the number found on the surface of ganglion cells. These autonomic neurons thus respond differently to denervation than do skeletal myofibers. The increase in ACh sensitivity displayed by cardiac ganglion cells upon denervation cannot be explained by changes in AChR number.
Recent results and new hardware developments for protein crystal growth in microactivity
NASA Technical Reports Server (NTRS)
Delucas, L. J.; Long, M. M.; Moore, K. M.; Smith, C.; Carson, M.; Narayana, S. V. L.; Carter, D.; Clark, A. D., Jr.; Nanni, R. G.; Ding, J.
1993-01-01
Protein crystal growth experiments have been performed on 16 space shuttle missions since April, 1985. The initial experiments utilized vapor diffusion crystallization techniques similar to those used in laboratories for earth-based experiments. More recent experiments have utilized temperature induced crystallization as an alternative method for growing high quality protein crystals in microgravity. Results from both vapor diffusion and temperature induced crystallization experiments indicate that proteins grown in microgravity may be larger, display more uniform morphologies, and yield diffraction data to significantly higher resolutions than the best crystals of these proteins grown on earth.
NASA Technical Reports Server (NTRS)
Ray, Chandra S.; Brow, Richard K.; Kim, Cheol W.; Reis, Signo T.
2004-01-01
The deformation and crystallization of Li(sub 2)O (center dot) 2SiO2 and Li(sub 2)O (center dot) 1.6SiO2 glass fibers subjected to a bending stress were measured as a function of time over the temperature range -50 to -150 C below the glass transition temperature (Tg). The glass fibers can be permanently deformed at temperatures about 100 C below T (sub)g, and they crystallize significantly at temperatures close to, but below T,, about 150 C lower than the onset temperature for crystallization for these glasses in the no-stress condition. The crystallization was found to occur only on the surface of the glass fibers with no detectable difference in the extent of crystallization in tensile and compressive stress regions. The relaxation mechanism for fiber deformation can be best described by a stretched exponential (Kohlrausch-Williams-Watt (KWW) approximation), rather than a single exponential model.The activation energy for stress relaxation, Es, for the glass fibers ranges between 175 and 195 kJ/mol, which is considerably smaller than the activation energy for viscous flow, E, (about 400 kJ/mol) near T, for these glasses at normal, stress-free condition. It is suspected that a viscosity relaxation mechanism could be responsible for permanent deformation and crystallization of the glass fibers below T,
Cura, C I; Lattes, R; Nagel, C; Gimenez, M J; Blanes, M; Calabuig, E; Iranzo, A; Barcan, L A; Anders, M; Schijman, A G
2013-12-01
Organ transplantation (TX) is a novel transmission modality of Chagas disease. The results of molecular diagnosis and characterization of Trypanosoma cruzi acute infection in naïve TX recipients transplanted with organs from infected deceased donors are reported. Peripheral blood and cerebrospinal fluid samples from the TX recipients of organs from infected donors were prospectively and sequentially studied for detection of T. cruzi by means of kinetoplastid DNA polymerase chain reaction (kDNA-PCR). In positive blood samples, a PCR algorithm for identification of T. cruzi Discrete Typing Units (DTUs) and quantitative real-time PCR (qPCR) to quantify parasitic loads were performed. Minicircle signatures of T. cruzi infecting populations were also analyzed using restriction fragment length polymorphism (RFLP)-PCR. Eight seronegative TX recipients from four infected donors were studied. In five, the infection was detected at 68.4 days post-TX (36-98 days). In one case, it was transmitted to two of three TX recipients. The comparison of the minicircle signatures revealed nearly identical RFLP-PCR profiles, confirming a common source of infection. The five cases were infected by DTU TcV. This report reveals the relevance of systematic monitoring of TX recipients using PCR strategies in order to provide an early diagnosis allowing timely anti-trypanosomal treatment. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.
Ung, Roth-Visal; Rouleau, Pascal; Guertin, Pierre A
2012-05-01
Chronic spinal cord injury may be complicated by weight loss, muscle atrophy, and bone loss. The authors identified a combination pharmacotherapy using buspirone, carbidopa, and L-DOPA (BCD) that elicits bouts of locomotor-like movements in spinal cord-transected (Tx) mice. They then evaluated the effects of 8 weeks of treadmill training in Tx mice that received BCD or BCD + clenbuterol, a monoaminergic agent with anabolic properties, on locomotor function, muscle atrophy, adipose tissue loss, and bone density measures. Induced locomotor movement, adipose tissue, skeletal muscle, and femoral bone properties were compared in unoperated control mice, operated controls (untreated, untrained Tx mice), and 2 groups of treated, trained Tx mice (Tx + BCD, Tx + BCD + clenbuterol) that also received training. BCD- and BCD + clenbuterol-treated mice showed comparable levels of locomotor movements that significantly improved over time. Soleus muscle mass and soleus and extensor digitorum longus cross-sectional area significantly increased in both groups of BCD-treated mice, with greater effects in BCD + clenbuterol-treated animals. Fiber type conversion, adipose tissues, bone mineral density, and content were reduced in all Tx groups compared with unoperated control mice. These findings suggest that locomotor movement and muscle properties can be restored to near-normal levels after several weeks of BCD treatment, regular training, and clenbuterol in completely paraplegic animals.
NASA Astrophysics Data System (ADS)
Rashid, M. Harunur; Huq, Redwan; Tanner, Mark R.; Chhabra, Sandeep; Khoo, Keith K.; Estrada, Rosendo; Dhawan, Vikas; Chauhan, Satendra; Pennington, Michael W.; Beeton, Christine; Kuyucak, Serdar; Norton, Raymond S.
2014-03-01
HsTX1 toxin, from the scorpion Heterometrus spinnifer, is a 34-residue, C-terminally amidated peptide cross-linked by four disulfide bridges. Here we describe new HsTX1 analogues with an Ala, Phe, Val or Abu substitution at position 14. Complexes of HsTX1 with the voltage-gated potassium channels Kv1.3 and Kv1.1 were created using docking and molecular dynamics simulations, then umbrella sampling simulations were performed to construct the potential of mean force (PMF) of the ligand and calculate the corresponding binding free energy for the most stable configuration. The PMF method predicted that the R14A mutation in HsTX1 would yield a > 2 kcal/mol gain for the Kv1.3/Kv1.1 selectivity free energy relative to the wild-type peptide. Functional assays confirmed the predicted selectivity gain for HsTX1[R14A] and HsTX1[R14Abu], with an affinity for Kv1.3 in the low picomolar range and a selectivity of more than 2,000-fold for Kv1.3 over Kv1.1. This remarkable potency and selectivity for Kv1.3, which is significantly up-regulated in activated effector memory cells in humans, suggest that these analogues represent valuable leads in the development of therapeutics for autoimmune diseases.
Niedzwiecki, M; Yamada, Y; Inci, I; Weder, W; Jungraithmayr, W
2016-01-01
Allergies are hypersensitive reactions of the immune system on antigen exposure similar to immune reactions after transplantation (Tx). Their activity can change after Tx. The lung as a transplantable organ is challenged two-fold, by antigens from the blood and the air environment. Herein we analyzed if airway allergies change after lung Tx. We systematically reviewed patients' airway allergies before and after lung Tx between 1992 and 2014. The course of lymphocytes, thrombocytes, and leukocytes, among them neutrophils, eosinophils, and basophils, was analyzed in patients in whom airway allergies have changed and in whom they did not change. From 362 lung transplanted patients, 44 patients had suffered from allergies before Tx (12.2%). In 20 of these patients (45.5%), airway allergies disappeared completely within 1 year after lung Tx and were persistently absent thereafter. In these patients, basophils and eosinophils decreased significantly (P < .0012); in contrast, cells did not decrease in patients whose allergies did not disappear. Leukocytes overall, and in particular, neutrophils, decreased significantly in patients whose allergy disappeared (P < .014, P < .012, respectively). Airway allergies disappeared in almost half of cases after lung Tx. Along with this reduction, basophils and eosinophils decreased as potentially responsible cells for this phenomenon. These findings may stimulate intensified research on basophils and eosinophils as major drivers of airway allergies. Copyright © 2016 Elsevier Inc. All rights reserved.
Dalmolin, Gerusa D; Bannister, Kirsty; Gonçalves, Leonor; Sikandar, Shafaq; Patel, Ryan; Cordeiro, Marta do Nascimento; Gomez, Marcus Vinícius; Ferreira, Juliano; Dickenson, Anthony H
2017-07-01
Drugs that counteract nociceptive transmission in the spinal dorsal horn preferentially after nerve injury are being pursued as possible neuropathic pain treatments. In a previous behavioural study, the peptide toxin Tx3-3, which blocks P/Q- and R-type voltage-gated calcium channels, was effective in neuropathic pain models. In the present study, we aimed to investigate the effect of Tx3-3 on dorsal horn neuronal responses in rats under physiological conditions and neuropathic pain condition induced by spinal nerve ligation (SNL). In vivo electrophysiological recordings of dorsal horn neuronal response to electrical and natural (mechanical and thermal) stimuli were made in rats under normal physiological state (naive rats) or after the SNL model of neuropathic pain. Tx3-3 (0.3-100 pmol/site) exhibited greater inhibitory effect on electrical-evoked neuronal response of SNL rats than naive rats, inhibiting nociceptive C-fibre and Aδ-fibre responses only in SNL rats. The wind-up of neurones, a measurement of spinal cord hyperexcitability, was also more susceptible to a dose-related inhibition by Tx3-3 after nerve injury. Moreover, Tx3-3 exhibited higher potency to inhibit mechanical- and thermal-evoked neuronal response in conditions of neuropathy. Tx3-3 mediated differential inhibitory effect under physiological and neuropathic conditions, exhibiting greater potency in conditions of neuropathic pain.
Laur, Amandine Marine; Floch, Pauline; Chambonnier, Lucie; Benejat, Lucie; Korolik, Victoria; Giese, Alban; Dubus, Pierre; Mégraud, Francis; Bandeira, Antonio; Lehours, Philippe
2016-01-19
It has been postulated that the emergence of autoimmune gastritis in neonatal thymectomised (d3Tx) BALB/c mice may be a consequence of post-surgery deficit in Tregs. In this study, previously obtained samples from d3Tx mice were used in order to determine whether thymectomy creates a deficit in this T cell subset thereby allowing the emergence of autoimmune phenomena as a prerequisite for GML. The splenic Treg reserve and the local recruitment of these cells in the gastric mucosa were investigated using complementary molecular and immunohistochemistry approaches. Higher Foxp3/CD3 ratios were found in the spleen of non-infected d3Tx mice compared to non-thymectomised (NTx) controls. These results indicate a relative enrichment of Tregs following thymectomy in adult mice. The absence of Treg depletion in d3Tx mice is in line with the absence of auto-immune gastritis in non-infected d3Tx mice. Higher levels of T cell and Treg infiltration were also found in the stomach of GML-developing d3Tx mice versus NTx mice. Surprisingly, inflammatory scores inversely correlated with the bacterial inoculum. The presence of a small Treg containing compartment among gastric biopsies of GML developing d3Tx mice may play a role in perseverance of a minimal bacterial numbers thereby maintaining an antigen-dependent stimulation and proliferation.
Astigmatic Herriott cell for optical refrigeration
NASA Astrophysics Data System (ADS)
Gragossian, Aram; Meng, Junwei; Ghasemkhani, Mohammadreza; Albrecht, Alexander R.; Sheik-Bahae, Mansoor
2017-01-01
Cooling rare-earth-doped crystals to the lowest temperature possible requires enhanced resonant absorption and high-purity crystals. Since resonant absorption decreases as the crystal is cooled, the only path forward is to increase the number of roundtrips that the laser makes inside the crystal. To achieve even lower temperatures than previously reported, we have employed an astigmatic Herriott cell to improve laser absorption at low temperatures. Preliminary results indicate improvement over previous designs. This cavity potentially enables us to use unpolarized high-power fiber lasers, and to achieve much higher cooling power for practical applications.
Study of the possibility of growing germanium single crystals under low temperature gradients
NASA Astrophysics Data System (ADS)
Moskovskih, V. A.; Kasimkin, P. V.; Shlegel, V. N.; Vasiliev, Y. V.; Gridchin, V. A.; Podkopaev, O. I.; Zhdankov, V. N.
2014-03-01
The possibility of growing germanium single crystals under low temperature gradients in order to produce a dislocation-free material has been studied. Germanium crystals with a dislocation density of about 100-200 cm-2 have been grown in a system with a weight control of crystal growth at maximum axial gradients of about 1.5 K/cm.
Glass formation and crystallization in high-temperature glass-ceramics and Si3N4
NASA Technical Reports Server (NTRS)
Drummond, Charles H., III
1991-01-01
The softening of glassy grain boundaries in ceramic matrix composites and Si3N4 at high temperatures reduces mechanical strength and the upper-use temperature. By crystallizing this glass to a more refractory crystalline phase, a material which performs at higher temperatures may result. Three systems were examined: a cordierite composition with ZrO2 as a nucleating agent; celsian compositions; and yttrium silicate glasses both in bulk and intergranular in Si3N4. For the cordierite compositions, a series of metastable phases was obtained. The crystallization of these compositions was summarized in terms of metastable ternary isothermal sections. Zircon formed at the expense of ZrO2 and spinel. In SiC composites, the transformations were slower. In celsian, two polymorphs were crystallized. One phase, hexacelsian, which always crystallized, even when metastable, had an undesirable volume change. The other phase, celsian, was very difficult to crystallize. In yttrium silicate bulk glasses, similar in composition to the intergranular glass in Si3N4, a number of polymorphs of Y2Si2O7 were crystallized. The conditions under which these polymorphs formed are compared with crystallization in Si3N4.
NASA Astrophysics Data System (ADS)
Jung, Sung Suk; Sohn, Il
2012-12-01
The crystallization behavior of a calcium-aluminate system with various MgO content from 2.5 to 7.5 wt pct and CaO/Al2O3 ratios between 0.8 and 1.2 has been examined using a confocal laser scanning microscope (CLSM). CCT (continuous cooling transformation) and time temperature transformation (TTT) diagrams were constructed to identify the primary crystal phase of slag at different compositions and at cooling rates between 25 and 800 K/minutes. In the slag at a CaO/Al2O3 ratio of 1.0, crystallization temperature increased during isothermal and continuous cooling with higher MgO content, and the shortest incubation time was observed at 5 wt pct MgO. When MgO content was fixed to be 5 wt pct, crystallization temperature increased with lower CaO/Al2O3 ratio. According to the slag composition, cooling rates and temperature, the primary phase could be CA, or C5A3, or C3A, or C3MA2, or MgO, and the crystal morphology changes from dendrites to faceted crystals to columnar crystals in this composition range.
77 FR 15846 - Advisory Committee on Minority Veterans; Notice of Meeting
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Military Family Coping Project
2013-09-01
ORGANIZATION: Baylor University Waco , TX 76798 REPORT DATE: September 2013 TYPE OF REPORT: Annual PREPARED FOR: U.S. Army Medical...ORGANIZATION REPORT NUMBER Waco , TX 76798 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S...CA. Dennis, Regina (Staff Writer). (2012, February 28). Baylor, Waco VA hospital studying veterans’ family stress. Waco , TX: Tribune Herald
"60x30TX" 2017 Progress Report
ERIC Educational Resources Information Center
Texas Higher Education Coordinating Board, 2017
2017-01-01
Central to the goals of "60x30TX" is maintaining Texas as a global economic player by having an educated population, making them aware of their marketable skills, and helping them manage their student loan debt. If the 2016 progress report for "60x30TX" was about getting out the word, this report is about expanding that reach…
Low-Temperature Growth of Two-Dimensional Layered Chalcogenide Crystals on Liquid.
Zhou, Yubing; Deng, Bing; Zhou, Yu; Ren, Xibiao; Yin, Jianbo; Jin, Chuanhong; Liu, Zhongfan; Peng, Hailin
2016-03-09
The growth of high-quality two-dimensional (2D) layered chalcogenide crystals is highly important for practical applications in future electronics, optoelectronics, and photonics. Current route for the synthesis of 2D chalcogenide crystals by vapor deposition method mainly involves an energy intensive high-temperature growth process on solid substrates, often suffering from inhomogeneous nucleation density and grain size distribution. Here, we first demonstrate a facile vapor-phase synthesis of large-area high-quality 2D layered chalcogenide crystals on liquid metal surface with relatively low surface energy at a growth temperature as low as ∼100 °C. Uniform and large-domain-sized 2D crystals of GaSe and GaxIn1-xSe were grown on liquid metal surface even supported on a polyimide film. As-grown 2D GaSe crystals have been fabricated to flexible photodetectors, showing high photoresponse and excellent flexibility. Our strategy of energy-sustainable low-temperature growth on liquid metal surface may open a route to the synthesis of high-quality 2D crystals of Ga-, In-, Bi-, Hg-, Pb-, or Sn-based chalcogenides and halides.
The Effect of Solution Thermal History on Chicken Egg White Lysozyme Nucleation
NASA Technical Reports Server (NTRS)
Burke, Michael W.; Judge, Russell A.; Pusey, Marc L.
2001-01-01
Proteins are highly flexible molecules and often exhibit defined conformational changes in response to changes in the ambient temperature. Chicken egg white lysozyme has been previously shown to undergo an apparent structural change when warmed above the tetragonal/orthorhombic phase transition temperature. This is reflected by a change in the habit of the tetragonal and orthorhombic crystals so formed. In this study, we show that possible conformational changes induced by heating are stable and apparently non-reversible by simple cooling. Exposure of protein solutions to temperatures above the phase change transition temperature, before combining with precipitant solution to begin crystallization, reduces final crystal numbers. Protein that is briefly warmed to 37 C, then cooled shows no sign of reversal to the unheated nucleation behavior even after storage for four weeks at 4 C. The change in nucleation behavior of tetragonal lysozyme crystals, attributed to a structural shift, occurs faster the greater the exposure to temperature above the equi-solubility point for the two phases. Heating for 2 hours at 48 C reduces crystal numbers by 20 fold in comparison to the same solution heated for the same time at 30 C. Thermal treatment of solutions is therefore a possible tool to reduce crystal numbers and increase crystal size. The effects of a protein's previous thermal history are now shown to be a potentially critical factor in subsequent macromolecule crystal nucleation and growth studies.
The Effect of Solution Thermal History on Chicken Egg White Lysozyme Nucleation
NASA Technical Reports Server (NTRS)
Burke, Michael W.; Judge, Russell A.; Pusey, Marc L.; Rose, M. Franklin (Technical Monitor)
2000-01-01
Proteins are highly flexible molecules and often exhibit defined conformational changes in response to changes in the ambient temperature. Chicken egg white lysozyme has been previously shown to undergo an apparent structural change when warmed above the tetragonal/orthorhombic phase transition temperature. This is reflected by a change in the habit of the tetragonal and orthorhombic crystals so formed. In this study we show that possible conformational changes induced by heating are stable and apparently non- reversible by simple cooling. Exposure of protein solutions to temperatures above the phase change transition temperature, before combining with precipitant solution to begin crystallization, reduces final crystal numbers. Protein that is briefly warmed to 37 C, then cooled shows no sign of reversal to the unheated nucleation behavior even after storage for 4 weeks at 4 C. The change in nucleation behavior of tetragonal lysozyme crystals, attributed to a structural shift, occurs faster the greater the exposure to temperature above the equi-solubility point for the two phases. Heating for 2 h at 48 C reduces crystal numbers by 20 fold in comparison to the same solution heated for the same time at 30 C. Thermal treatment of solutions is therefore a possible tool to reduce crystal numbers and increase crystal size. The effects of a protein's previous thermal history are now shown to be a potentially critical factor in subsequent macromolecule crystal nucleation and growth studies.
Rate limits in silicon sheet growth - The connections between vertical and horizontal methods
NASA Technical Reports Server (NTRS)
Thomas, Paul D.; Brown, Robert A.
1987-01-01
Meniscus-defined techniques for the growth of thin silicon sheets fall into two categories: vertical and horizontal growth. The interactions of the temperature field and the crystal shape are analyzed for both methods using two-dimensional finite-element models which include heat transfer and capillarity. Heat transfer in vertical growth systems is dominated by conduction in the melt and the crystal, with almost flat melt/crystal interfaces that are perpendicular to the direction of growth. The high axial temperature gradients characteristic of vertical growth lead to high thermal stresses. The maximum growth rate is also limited by capillarity which can restrict the conduction of heat from the melt into the crystal. In horizontal growth the melt/crystal interface stretches across the surface of the melt pool many times the crystal thickness, and low growth rates are achievable with careful temperature control. With a moderate axial temperature gradient in the sheet a substantial portion of the latent heat conducts along the sheet and the surface of the melt pool becomes supercooled, leading to dendritic growth. The thermal supercooling is surpressed by lowering the axial gradient in the crystal; this configuration is the most desirable for the growth of high quality crystals. An expression derived from scaling analysis relating the growth rate and the crucible temperature is shown to be reliable for horizontal growth.
Fe-Al alloy single-crystal thin film preparation for basic magnetic measurements
NASA Astrophysics Data System (ADS)
Abe, Tatsuya; Kawai, Tetsuroh; Futamoto, Masaaki; Ohtake, Mitsuru; Inaba, Nobuyuki
2018-04-01
Fe100-xAlx (x = 0, 4, 10, 20, 30 at. %) alloy films of 40 nm thickness are prepared on MgO(001) single-crystal substrates by varying substrate temperature from room temperature to 600 °C. Single-crystal films of (001) orientation with bcc-based disordered A2 structure are obtained for the Al content range of x = 0 - 20 at. %. An ordered phase of DO3 structure is observed in Fe70Al30 films prepared at temperatures higher than 200 °C, whereas (001) oriented single-crystal films of A2 structure are obtained when prepared at room temperature. The film surface profile does not depend much on the film composition, while the surface roughness increases with increasing substrate temperature. Island-like crystals are observed for films prepared at 600°C for all compositions. Difference in lattice spacing measured parallel and perpendicular to the substrate is noted for the single-crystal thin films and it increases with increasing Al content. The lattice strain in single-crystal film is caused possibly to accommodate the lattice mismatch with the MgO substrate. The (001)-oriented single-crystal films with A2 structure show four-fold symmetries in in-plane magnetic anisotropy with the easy magnetization axis A2[100] and the hard magnetization axis A2[110], whereas the films with DO3 ordered structure show almost isotropic magnetic properties.
Crop-climate relationships of cereals in Greece and the impacts of recent climate trends
NASA Astrophysics Data System (ADS)
Mavromatis, Theodoros
2015-05-01
Notwithstanding technological developments, agricultural production is still affected by uncontrollable factors, such weather and climate. Within this context, the present study aims at exploring the relative influence of growing season climate on the yields of major cereals (hard and soft wheat, maize, and barley) on a regional scale in Greece. To this end, crop-climate relationships and the impacts of climate trends over the period 1978-2005 were explored using linear regression and change point analysis (CPA). Climate data used include maximum (Tx) and minimum temperature (Tn), diurnal temperature range (Tr), precipitation (Prec), and solar radiation (Rad). Temperature effects were the most substantial. Yields reduced by 1.8-7.1 %/°C with increasing Tx and by 1.4-6.1 %/°C with decreasing Tr. The warming trends of Tn caused bilateral yield effects (from -3.7 to 8.4 %/°C). The fewer significantly increasing Rad and decreasing Prec anomalies were associated with larger yield decreases (within the range of 2.2 % MJ/m2/day (for maize) to 4.9 % MJ/m2/day (for hard wheat)) and smaller yield increases (from 0.04 to 1.4 %/mm per decade), respectively. Wheat and barley—the most vulnerable cereals—were most affected by the trends of extreme temperatures and least by Tr. On the contrary, solar radiation has proven to be the least affecting climate variable on all cereals. Despite the similarity in the direction of crop responses with both analyses, yield changes were much more substantial in the case of CPA analysis. In conclusion, regional climate change has affected Greek cereal productivity, in a few, but important for cereal production, regions. The results of this study are expected to be valuable in anticipating the effects of weather/climate on other warm regions worldwide, where the upper temperature limit for some cereals and further changes in climate may push them past suitability for their cultivation.
Athermal channeled spectropolarimeter
Jones, Julia Craven
2015-12-08
A temperature insensitive (athermal) channeled spectropolarimeter (CSP) is described. The athermal CSP includes a crystal retarder formed of a biaxial crystal. The crystal retarder has three crystal axes, wherein each axis has its own distinct index of refraction. The axes are oriented in a particular manner, causing an amplitude modulating carrier frequency induced by the crystal retarder to be thermally invariant. Accordingly, a calibration beam technique can be used over a relatively wide range of ambient temperatures, with a common calibration data set.
The Effect of Solution Conditions on the Nucleation Kinetics of Tetragonal Lysozyme Crystals
NASA Technical Reports Server (NTRS)
Judge, Russell A.; Baird, James K.; Pusey, Marc L.
1998-01-01
An understanding of protein crystal nucleation rates and the effect of solution conditions upon them, is fundamental to the preparation of protein crystals of the desired size and shape for X-ray diffraction analysis. The ability to predict the effect of supersaturation, temperature, pH and precipitant concentration on the number and size of crystals formed is of great benefit in the pursuit of protein structure analysis. In this study we experimentally examine the effect of supersaturation, temperature, pH and sodium chloride concentration on the nucleation rate of tetragonal chicken egg white lysozyme crystals. In order to do this batch crystallization plates were prepared at given solution concentrations and incubated at three different temperatures over the period of one week. The number of crystals per well with their size and dimensions were recorded and correlated against solution conditions. Duplicate experiments indicate the reproducibility of the technique. Although it is well known that crystal numbers increase with increasing supersaturation, large changes in crystal number were also correlated against solution conditions of temperature, pH and salt concentration over the same supersaturation ranges. Analysis of these results enhance our understanding of the effect of solution conditions such as the dramatic effect that small changes in charge and ionic strength can have on the number of tetragonal lysozyme crystals that form and grow in solution.
Spectral studies of N-nonyl acridine orange in anionic, cationic and neutral surfactants
NASA Astrophysics Data System (ADS)
Wiosetek-Reske, Agnieszka M.; Wysocki, Stanisław
2006-08-01
The spectroscopic and photophysical properties of N-nonyl acridine orange - a metachromatic dye useful as a mitochondrial probe in living cells - are reported in water and microheterogeneous media: anionic sodium dodecylsulfate (SDS), cationic cetyltrimethylammonium bromide (CTAB) and neutral octylophenylpolyoxyethylene ether (TX-100). The spectral changes of N-nonyl acridine orange were observed in the presence of varying amount of SDS, CTAB and TX-100 and indicated formation of a dye-surfactant complex. The spectral changes were also regarded to be caused by the incorporation of dye molecules to micelles. It was proved by calculated values Kb and f in the following order: Kb TX-100 > Kb CTAB > Kb SDS and fTX-100 > fCTAB > fSDS. NAO binds to the micelle regardless the micellar charge. There are two types of interactions between NAO and micelles: hydrophobic and electrostatic. The hydrophobic interactions play a dominant role in binding of the dye to neutral TX-100. The unexpected fact of the binding NAO to cationic CTAB can be explained by a dominant role of hydrophobic interactions over electrostatic repulsion. Therefore, the affinity of NAO to CTAB is smaller than TX-100. Electrostatic interactions play an important role in binding of NAO to anionic micelles SDS. We observed a prolonged fluorescence lifetime after formation of the dye-surfactant complex τSDS > τTX-100 > τCTAB > τwater, the dye being protected against water in this environment. TX-100 is found to stabilize the excited state of NAO which is more polar than the ground state. Spectroscopic and photophysical properties of NAO will be helpful for a better understanding of the nature of binding and distribution inside mammalian cells.
Nunes, K P; Wynne, B M; Cordeiro, M N; Borges, M H; Richardson, M; Leite, R; DeLima, M E; Webb, R C
2012-01-01
Erectile dysfunction (ED) mechanisms in diabetic patients are multifactorial and often lead to resistance to current therapy. Animal toxins have been used as pharmacological tools to study penile erection. Human accidents involving the venom of Phoneutria nigriventer spider are characterized by priapism. We hypothesize that PnTx2-6 potentiates cavernosal relaxation in diabetic mice by increasing cyclic guanosine monophosphate (cGMP). This effect is neuronal nitric oxide synthase (nNOS) dependent. Cavernosal strips were contracted with phenylephrine (10(-5) M) and relaxed by electrical field stimulation (20 V, 1-32 Hz) in the presence or absence of PnTx2-6 (10(-8) M). Cavernosal strips from nNOS- and endothelial nitric oxide synthase (eNOS)-knockout (KO) mice, besides nNOS inhibitor (10(-5) M), were used to evaluate the role of this enzyme in the potentiation effect evoked by PnTx2-6. Tissue cGMP levels were determined after stimulation with PnTx2-6 in presence or absence of N-nitro-L-arginine methyl ester (L-NAME) (10(-4) M) and ω-conotoxin GVIA (10(-6) M), an N-type calcium channel inhibitor. Results showed that PnTx2-6 enhanced cavernosal relaxation in diabetic mice (65%) and eNOS KO mice, but not in nNOS KO mice. The toxin effect in the cavernosal relaxation was abolished by nNOS inhibitor. cGMP levels are increased by PnTx2-6, however, L-NAME abolished this enhancement as well as ω-conotoxin GVIA. We conclude that PnTx2-6 facilitates penile relaxation in diabetic mice through a mechanism dependent on nNOS, probably via increasing nitric oxide/cGMP production.
Further insights into brevetoxin metabolism by de novo radiolabeling.
Calabro, Kevin; Guigonis, Jean-Marie; Teyssié, Jean-Louis; Oberhänsli, François; Goudour, Jean-Pierre; Warnau, Michel; Bottein, Marie-Yasmine Dechraoui; Thomas, Olivier P
2014-06-10
The toxic dinoflagellate Karenia brevis, responsible for early harmful algal blooms in the Gulf of Mexico, produces many secondary metabolites, including potent neurotoxins called brevetoxins (PbTx). These compounds have been identified as toxic agents for humans, and they are also responsible for the deaths of several marine organisms. The overall biosynthesis of these highly complex metabolites has not been fully ascertained, even if there is little doubt on a polyketide origin. In addition to gaining some insights into the metabolic events involved in the biosynthesis of these compounds, feeding studies with labeled precursors helps to discriminate between the de novo biosynthesis of toxins and conversion of stored intermediates into final toxic products in the response to environmental stresses. In this context, the use of radiolabeled precursors is well suited as it allows working with the highest sensitive techniques and consequently with a minor amount of cultured dinoflagellates. We were then able to incorporate [U-¹⁴C]-acetate, the renowned precursor of the polyketide pathway, in several PbTx produced by K. brevis. The specific activities of PbTx-1, -2, -3, and -7, identified by High-Resolution Electrospray Ionization Mass Spectrometer (HRESIMS), were assessed by HPLC-UV and highly sensitive Radio-TLC counting. We demonstrated that working at close to natural concentrations of acetate is a requirement for biosynthetic studies, highlighting the importance of highly sensitive radiolabeling feeding experiments. Quantification of the specific activity of the four, targeted toxins led us to propose that PbTx-1 and PbTx-2 aldehydes originate from oxidation of the primary alcohols of PbTx-7 and PbTx-3, respectively. This approach will open the way for a better comprehension of the metabolic pathways leading to PbTx but also to a better understanding of their regulation by environmental factors.
Further Insights into Brevetoxin Metabolism by de Novo Radiolabeling
Calabro, Kevin; Guigonis, Jean-Marie; Teyssié, Jean-Louis; Oberhänsli, François; Goudour, Jean-Pierre; Warnau, Michel; Dechraoui Bottein, Marie-Yasmine; Thomas, Olivier P.
2014-01-01
The toxic dinoflagellate Karenia brevis, responsible for early harmful algal blooms in the Gulf of Mexico, produces many secondary metabolites, including potent neurotoxins called brevetoxins (PbTx). These compounds have been identified as toxic agents for humans, and they are also responsible for the deaths of several marine organisms. The overall biosynthesis of these highly complex metabolites has not been fully ascertained, even if there is little doubt on a polyketide origin. In addition to gaining some insights into the metabolic events involved in the biosynthesis of these compounds, feeding studies with labeled precursors helps to discriminate between the de novo biosynthesis of toxins and conversion of stored intermediates into final toxic products in the response to environmental stresses. In this context, the use of radiolabeled precursors is well suited as it allows working with the highest sensitive techniques and consequently with a minor amount of cultured dinoflagellates. We were then able to incorporate [U-14C]-acetate, the renowned precursor of the polyketide pathway, in several PbTx produced by K. brevis. The specific activities of PbTx-1, -2, -3, and -7, identified by High-Resolution Electrospray Ionization Mass Spectrometer (HRESIMS), were assessed by HPLC-UV and highly sensitive Radio-TLC counting. We demonstrated that working at close to natural concentrations of acetate is a requirement for biosynthetic studies, highlighting the importance of highly sensitive radiolabeling feeding experiments. Quantification of the specific activity of the four, targeted toxins led us to propose that PbTx-1 and PbTx-2 aldehydes originate from oxidation of the primary alcohols of PbTx-7 and PbTx-3, respectively. This approach will open the way for a better comprehension of the metabolic pathways leading to PbTx but also to a better understanding of their regulation by environmental factors. PMID:24918358
Mendieta, Liliana; Granado, Noelia; Aguilera, José; Tizabi, Yousef; Moratalla, Rosario
2016-08-01
The C-terminal domain of the heavy chain of tetanus toxin (Hc-TeTx) is a nontoxic peptide with demonstrated in vitro and in vivo neuroprotective effects against striatal dopaminergic damage induced by 1-methyl-4-phenylpyridinium and 6-hydoxydopamine, suggesting its possible therapeutic potential in Parkinson's disease. Methamphetamine, a widely abused psychostimulant, has selective dopaminergic neurotoxicity in rodents, monkeys, and humans. This study was undertaken to determine whether Hc-TeTx might also protect against methamphetamine-induced dopaminergic neurotoxicity and the consequent motor impairment. For this purpose, we treated mice with a toxic regimen of methamphetamine (4mg/kg, 3 consecutive i.p. injections, 3 hours apart) followed by 3 injections of 40 ug/kg of Hc-TeTx into grastrocnemius muscle at 1, 24, and 48 hours post methamphetamine treatment. We found that Hc-TeTx significantly reduced the loss of dopaminergic markers tyrosine hydroxylase and dopamine transporter and the increases in silver staining (a well stablished degeneration marker) induced by methamphetamine in the striatum. Moreover, Hc-TeTx prevented the increase of neuronal nitric oxide synthase but did not affect microglia activation induced by methamphetamine. Stereological neuronal count in the substantia nigra indicated loss of tyrosine hydroxylase-positive neurons after methamphetamine that was partially prevented by Hc-TeTx. Importantly, impairment in motor behaviors post methamphetamine treatment were significantly reduced by Hc-TeTx. Here we demonstrate that Hc-TeTx can provide significant protection against acute methamphetamine-induced neurotoxicity and motor impairment, suggesting its therapeutic potential in methamphetamine abusers. © The Author 2016. Published by Oxford University Press on behalf of CINP.
Krishnarjuna, Bankala; Villegas-Moreno, Jessica; Mitchell, Michela L; Csoti, Agota; Peigneur, Steve; Amero, Carlos; Pennington, Michael W; Tytgat, Jan; Panyi, Gyorgy; Norton, Raymond S
2018-05-19
Sea anemone venom is rich in bioactive compounds, including peptides containing multiple disulfide bridges. In a transcriptomic study on Oulactis sp., we identified the putative 36-residue peptide, OspTx2b, which is an isoform of the K V channel blocker OspTx2a (Sunanda P et al. [2018] Identification, chemical synthesis, structure and function of a new K V 1 channel blocking peptide from Oulactis sp. Peptide Science, in press). As OspTx2b contains a ShK/BgK-like cysteine framework, with high amino acid sequence similarity to BgK, we were interested to investigate its structure and function. The solution structure of OspTx2b was determined using nuclear magnetic resonance spectroscopy. OspTx2b does indeed possess a BgK-like scaffold, with the same disulfide bond connectivities. The orientation of the Lys-Tyr dyad in OspTx2b is more similar to that in ShK than in BgK. However, it failed to show against a range of voltage-gated potassium channels in Xenopus oocytes and human T lymphocytes. OspTx2b also showed no growth inhibitory activity against several strains of bacteria and fungi. Having a BgK-like fold with the Lys-Tyr dyad but no BgK-like activity highlights the importance of key amino acid residues in BgK that are missing in OspTx2b. The lack of activity against the K V channels assessed in this study emphasises that the ShK/BgK scaffold is capable of supporting functional activity beyond potassium channel blockade. Copyright © 2018. Published by Elsevier Ltd.
COTTRELL, GRAEME S.; AMADESI, SILVIA; PIKIOS, STELLA; CAMERER, ERIC; WILLARDSEN, J. ADAM; MURPHY, BRETT R.; CAUGHEY, GEORGE H.; WOLTERS, PAUL J.; COUGHLIN, SHAUN R.; PETERSON, ANDERS; KNECHT, WOLFGANG; POTHOULAKIS, CHARALABOS; BUNNETT, NIGEL W.; GRADY, EILEEN F.
2008-01-01
Background & Aims We studied the role of protease-activated receptor 2 (PAR2) and its activating enzymes, trypsins and tryptase, in Clostridium difficile toxin A (TxA)-induced enteritis. Methods We injected TxA into ileal loops in PAR2 or dipeptidyl peptidase I (DPPI) knockout mice or in wild-type mice pretreated with tryptase inhibitors (FUT-175 or MPI-0442352) or soybean trypsin inhibitor. We examined the effect of TxA on expression and activity of PAR2 and trypsin IV messenger RNA in the ileum and cultured colonocytes. We injected activating peptide (AP), trypsins, tryptase, and p23 in wild-type mice, some pretreated with the neurokinin 1 receptor antagonist SR140333. Results TxA increased fluid secretion, myeloperoxidase activity in fluid and tissue, and histologic damage. PAR2 deletion decreased TxA-induced ileitis, reduced luminal fluid secretion by 20%, decreased tissue and fluid myeloperoxidase by 50%, and diminished epithelial damage, edema, and neutrophil infiltration. DPPI deletion reduced secretion by 20% and fluid myeloperoxidase by 55%. In wild-type mice, FUT-175 or MPI-0442352 inhibited secretion by 24%−28% and tissue and fluid myeloperoxidase by 31%−71%. Soybean trypsin inhibitor reduced secretion to background levels and tissue myeloperoxidase by up to 50%. TxA increased expression of PAR2 and trypsin IV in enterocytes and colonocytes and caused a 2-fold increase in Ca2+ responses to PAR2 AP. AP, tryptase, and trypsin isozymes (trypsin I/II, trypsin IV, p23) caused ileitis. SR140333 prevented AP-induced ileitis. Conclusions PAR2 and its activators are proinflammatory in TxA-induced enteritis. TxA stimulates existing PAR2 and up-regulates PAR2 and activating proteases, and PAR2 causes inflammation by neurogenic mechanisms. PMID:17570216
Mendoza-Novelo, Birzabith; Castellano, Laura E; Padilla-Miranda, Ruth G; Lona-Ramos, María C; Cuéllar-Mata, Patricia; Vega-González, Arturo; Murguía-Pérez, Mario; Mata-Mata, José L; Ávila, Eva E
2016-11-01
The extracellular matrix molecules remaining in bioscaffolds derived from decellularized xenogeneic tissues appear to be important for inducing cell functions conducting tissue regeneration. Here, we studied whether decellularization methods, that is, detergent Triton X-100 (TX) alone and TX combined with reversible alkaline swelling (STX), applied to bovine pericardial tissue, could affect the bioscaffold components. The in vitro macrophage response, subdermal biodegradation, and cell infiltration were also studied. The results indicate a lower leaching of fibronectin, but a higher leaching of laminin and sulfated glycosaminoglycans from tissues decellularized with STX and TX, respectively. The in vitro secretion of interleukin-6 and monocyte chemoattractant protein by RAW264.7 macrophages is promoted by decellularized bioscaffold leachates. A lower polymorphonuclear cell density is observed around decellularized bioscaffolds at 1-day implantation; concurrently showing a higher cell infiltration in STX- than in TX-implant. Cells infiltrated into TX-implant show a fibroblastic morphology at 7-day implantation, concurrently the capillary formation is observed at 14-day. Pericardial bioscaffolds suffer biodegradation more pronounced in STX- than in TX-implant. Both TX and STX decellularization methods favor a high leaching of basal lamina components, which presumably promotes a faster macrophage stimulation compared to nondecellularized tissue, and appear to be associated with an increased host cell infiltration in a rat subdermal implantation. Meanwhile, the connective tissue components leaching from TX decellularized bioscaffolds, unlike the STX ones, appear to be associated with an enhanced angiogenesis accompanied by an early-promoted fibroblastic cell transition. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2810-2822, 2016. © 2016 Wiley Periodicals, Inc.
NASA Astrophysics Data System (ADS)
Harris, V. G.; Oliver, S. A.; Ayers, J. D.; Das, B. N.; Koon, N. C.
1996-04-01
The evolution of the local atomic environment around Fe atoms in very thin (15 nm), amorphous, partially crystallized and fully crystallized films of Fe80B20 was studied using extended x-ray absorption fine structure (EXAFS) measurements. The relative atomic fraction of each crystalline phase present in the annealed samples was extracted from the Fe EXAFS data by a least-squares fitting procedure, using data collected from t-Fe3B, t-Fe2B, and α-Fe standards. The type and relative fraction of the crystallization products follows the trends previously measured in Fe80B20 melt-spun ribbons, except for the fact that crystallization temperatures are ≊200 K lower than those measured in bulk equivalents. This greatly reduced crystallization temperature may arise from the dominant role of surface nucleation sites in the crystallization of very thin amorphous films.
Electron microscopy study of Ni induced crystallization in amorphous Si thin films
DOE Office of Scientific and Technical Information (OSTI.GOV)
Radnóczi, G. Z.; Battistig, G.; Pécz, B., E-mail: pecz.bela@ttk.mta.hu
2015-02-17
The crystallization of amorphous silicon is studied by transmission electron microscopy. The effect of Ni on the crystallization is studied in a wide temperature range heating thinned samples in-situ inside the microscope. Two cases of limited Ni source and unlimited Ni source are studied and compared. NiSi{sub 2} phase started to form at a temperature as low as 250°C in the limited Ni source case. In-situ observation gives a clear view on the crystallization of silicon through small NiSi{sub 2} grain formation. The same phase is observed at the crystallization front in the unlimited Ni source case, where a secondmore » region is also observed with large grains of Ni{sub 3}Si{sub 2}. Low temperature experiments show, that long annealing of amorphous silicon at 410 °C already results in large crystallized Si regions due to the Ni induced crystallization.« less
Crystal structure and vibrational spectra of melaminium arsenate
NASA Astrophysics Data System (ADS)
Anbalagan, G.; Marchewka, M. K.; Pawlus, K.; Kanagathara, N.
2015-01-01
The crystals of the new melaminium arsenate (MAS) [C3H7N6+ṡH2AsO4-] were obtained by the slow evaporation of an aqueous solution at room temperature. Single crystal X-ray diffraction analysis reveals that the crystal belongs to triclinic system with centro symmetric space group P-1. The crystals are built up from single protonated melaminium residues and single dissociated arsenate H2AsO4- anions. The protonated melaminium ring is almost planar. A combination of ionic and donor-acceptor hydrogen-bond interactions linking together the melaminium and arsenate residues forms a three-dimensional network. Vibrational spectroscopic analysis is reported on the basis of FT-IR and FT-Raman spectra recorded at room temperature. Hydrogen bonded network present in the crystal gives notable vibrational effect. DSC has also been performed for the crystal shows no phase transition in the studied temperature range (113-293 K).
Tranexamic Acid in cardiac surgery and postoperative seizures: a case report series.
Bell, David; Marasco, Silvana; Almeida, Aubrey; Rowland, Michael
2010-08-01
With the recent withdrawal of the antifibrinolytic aprotinin from the market, tranexamic acid (TxA) has become more widely used. This change has led to increasing concern about the side-effect profile of TxA, particularly the incidence of postoperative seizures. In this case series, we describe 7 patients over an 18-month period who had open-chamber cardiac surgery and developed seizures in the postoperative period. This incidence is increased compared with that of a cohort of patients in the previous 36 months who did not receive TxA (0.66% versus 0%; P < .05). The exact mechanism of TxA-induced seizures is thought to be via inhibition of gamma-aminobutyric acid receptors in neurons. Data from the neurosurgical literature show a well-established link between this antifibrinolytic and seizures. There is now increasing awareness of this association in cardiac surgery, particularly when high TxA doses are used.
NASA Astrophysics Data System (ADS)
Zhang, Fangkun; Liu, Tao; Huo, Yan; Guan, Runduo; Wang, Xue Z.
2017-07-01
In this paper the effects of operating conditions including cooling rate, initial supersaturation, and seeding temperature were investigated on the morphology evolution of β-L-glutamic acid (β-LGA) during seeded cooling crystallization. Based on the results of in-situ image acquisition of the crystal morphology evolution during the crystallization process, it was found that the crystal products tend to be plate-like or short rod-like under a slow cooling rate, low initial supersaturation, and low seeding temperature. In the opposite, the operating conditions of a faster cooling rate, higher initial supersaturation, and higher seeding temperature tend to produce long rod-like or needle-like crystals, and meanwhile, the length and width of crystal products will be increased together with a wider crystal size distribution (CSD). The aspect ratio of crystals, defined by the crystal length over width measured from in-situ or sample images, was taken as a shape index to analyze the crystal morphologies. Based on comparative analysis of the experimental results, guidelines on these operating conditions were given for obtaining the desired crystal shapes, along with the strategies for obtaining a narrower CSD for better product quality. Experimental verifications were performed to illustrate the proposed guidelines on the operating conditions for seeded cooling crystallization of LGA solution.
Pandalaneni, K; Amamcharla, J K
2016-07-01
Lactose accounts for about 75 and 85% of the solids in whey and deproteinized whey, respectively. Production of lactose is usually carried out by a process called crystallization. Several factors including rate of cooling, presence of impurities, and mixing speed influence the crystal size characteristics. To optimize the lactose crystallization process parameters to maximize the lactose yield, it is important to monitor the crystallization process. However, efficient in situ tools to implement at concentrations relevant to the dairy industry are lacking. The objective of the present work was to use a focused beam reflectance measurement (FBRM) system for in situ monitoring of lactose crystallization at supersaturated concentrations (wt/wt) 50, 55, and 60% at 20 and 30°C. The FBRM data were compared with Brix readings collected using a refractometer during isothermal crystallization. Chord length distributions obtained from FBRM in the ranges of <50 µm (fine crystals) and 50 to 300 µm (coarse crystals) were recorded and evaluated in relation to the extent of crystallization and rate constants deduced from the refractometer measurements. Extent of crystallization and rate constants increased with increasing supersaturation concentration and temperature. The measured fine crystal counts from FBRM increased at higher supersaturated concentration and temperature during isothermal crystallization. On the other hand, coarse counts were observed to increase with decreasing supersaturated concentration and temperature. Square weighted chord length distribution obtained from FBRM showed that as concentration increased, a decrease in chord lengths occurred at 20°C and similar observations were made from microscopic images. The robustness of FBRM in understanding isothermal lactose crystallization at various concentrations and temperatures was successfully assessed in the study. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Close up view under the Orbiter Discovery in the Vehicle ...
Close up view under the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. The view is under the port wing looking forward toward the main fuselage showing a detail of the landing gear and landing gear door. This view also shows the patterns of worn and replaced High-temperature Reusable Surface Insulation tiles. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX
Controllable fabrication of copper phthalocyanine nanostructure crystals.
Liu, Fangmei; Sun, Jia; Xiao, Si; Huang, Wenglong; Tao, Shaohua; Zhang, Yi; Gao, Yongli; Yang, Junliang
2015-06-05
Copper phthalocyanine (CuPc) nanostructure crystals, including nanoflower, nanoribbon, and nanowire, were controllably fabricated by temperature gradient physical vapor deposition (TG-PVD) through controlling the growth parameters. In a controllable growth system with carrier gas N2, nanoflower, nanoribbon, and nanowire crystals were formed in a high-temperature zone, medium-temperature zone, and low-temperature zone, respectively. They were proved to be β-phase, coexist of α-phase and β-phase, and α-phase respectively based on x-ray diffraction results. Furthermore, ultralong CuPc nanowires up to several millimeters could be fabricated by TG-PVD without carrier gas, and they were well-aligned to form large-area CuPc nanowire crystal arrays by the Langmuir-Blodgett method. The nanostructure crystals showed unusual optical absorption spectra from the ultraviolet-visible to near-infrared range, which was explained by the diffraction and scattering caused by the wavelength-sized nanostructures. These CuPc nanostructure crystals show potential applications in organic electronic and optoelectronic devices.
NASA Astrophysics Data System (ADS)
Yang, Xin-Bo; Xu, Jun; Li, Hong-Jun; Bi, Qun-Yu; Cheng, Yan; Su, Liang-Bi; Tang, Qiang
2010-04-01
Recently, α-Al2O3:C crystal with highly sensitive thermoluminescence (TL) and optically stimulated luminescence (OSL) has been successfully grown by the temperature gradient technique. This paper investigates the heating rate dependence of TL sensitivity, light-induced fading of TL signals and thermal stability of OSL of α-Al2O3:C crystals. As the heating rate increases, the integral TL response decreases and the dosimetric glow peak shifts to higher temperatures in α-Al2O3:C crystals. Light-induced fading of TL increases with the irradiation dose, and TL response decreases as the exposure time increases, especially in the first 15 minutes. With the increasing intensity of the exposure light, the TL fading of α-Al2O3:C crystal increases sharply. The OSL response of as-grown α-Al2O3:C crystal is quite stable below 373 K and decreases sharply for higher temperatures.
Lee, Sang-Yup; Gao, Xueyun; Matsui, Hiroshi
2008-01-01
The room temperature synthesis of β-Ga2O3 nanocrystal was examined by coupling two biomimetic crystallization techniques, the enzymatic peptide nano-assembly templating and the aggregation-driven crystallization. The catalytic template of peptide assembly nucleated and mineralized primary β-Ga2O3 crystals, and then fused them to grow single-crystalline and monodisperse nanoparticles in the cavity of the peptide assembly at room temperature. In this work, the peptide assembly was exploited as a nano-reactor with an enzymatic functionality catalyzing the hydrolysis of gallium precursors. In addition, the characteristic ring-structure of peptide assembly is expected to provide an efficient dehydration pathway and the crystallization control over the surface tension, which are advantageous for the β-Ga2O3 crystal growth. This multifunctional peptide assembly could be applied for syntheses of a variety of nanomaterials that are kinetically difficult to grow at room temperature. PMID:17302413
Method for harvesting rare earth barium copper oxide single crystals
Todt, V.R.; Sengupta, S.; Shi, D.
1996-04-02
A method of preparing high temperature superconductor single crystals is disclosed. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals of the high temperature superconductor, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals of the high temperature superconductor on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals melted, allowing the wicking away of the peritectic liquid. 2 figs.
Method for harvesting rare earth barium copper oxide single crystals
Todt, Volker R.; Sengupta, Suvankar; Shi, Donglu
1996-01-01
A method of preparing high temperature superconductor single crystals. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals of the high temperature superconductor, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals of the high temperature superconductor on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals melted, allowing the wicking away of the peritectic liquid.
Development of a Single-Crystal Fifth-Generation Nickel Superalloy
NASA Astrophysics Data System (ADS)
Petrushin, N. V.; Elyutin, E. S.; Visik, E. M.; Golynets, S. A.
2017-11-01
The chemical and phase compositions of a rhenium-ruthenium-containing fifth-generation VZhM8 nickel superalloy, which is intended for single-crystal turbine blades of an aviation engine, are calculated using computer simulation. VZhM8 alloy <001>, <011>, and <111> single crystals are fabricated. The microstructure, the γ/γ' misfit, the segregation coefficients of alloying elements, the dissolution temperature of the γ' phase, and the solidus and liquidus temperatures of the VZhM8 alloy single crystals in the as-cast state and after heat treatment are studied. The temperature-time dependences of the static elastic modulus, the short-term mechanical properties, and the long-term strength of the alloy single crystals are determined
Crystal face temperature determination means
Nason, Donald O.; Burger, Arnold
1994-01-01
An optically transparent furnace (10) having a detection apparatus (29) with a pedestal (12) enclosed in an evacuated ampule (16) for growing a crystal (14) thereon. Temperature differential is provided by a source heater (20), a base heater (24) and a cold finger (26) such that material migrates from a polycrystalline source material (18) to grow the crystal (14). A quartz halogen lamp (32) projects a collimated beam (30) onto the crystal (14) and a reflected beam (34) is analyzed by a double monochromator and photomultiplier detection spectrometer (40) and the detected peak position (48) in the reflected energy spectrum (44) of the reflected beam (34) is interpreted to determine surface temperature of the crystal (14).
Sink property of metallic glass free surfaces
Shao, Lin; Fu, Engang; Price, Lloyd; ...
2015-03-16
When heated to a temperature close to glass transition temperature, metallic glasses (MGs) begin to crystallize. Under deformation or particle irradiation, crystallization occurs at even lower temperatures. Hence, phase instability represents an application limit for MGs. Here, we report that MG membranes of a few nanometers thickness exhibit properties different from their bulk MG counterparts. The study uses in situ transmission electron microscopy with concurrent heavy ion irradiation and annealing to observe crystallization behaviors of MGs. For relatively thick membranes, ion irradiations introduce excessive free volumes and thus induce nanocrystal formation at a temperature linearly decreasing with increasing ion fluences.more » For ultra-thin membranes, however, the critical temperature to initiate crystallization is about 100 K higher than the bulk glass transition temperature. Molecular dynamics simulations indicate that this effect is due to the sink property of the surfaces which can effectively remove excessive free volumes. These findings suggest that nanostructured MGs having a higher surface to volume ratio are expected to have higher crystallization resistance, which could pave new paths for materials applications in harsh environments requiring higher stabilities.« less
Shete, Ganesh; Khomane, Kailas S; Bansal, Arvind Kumar
2014-01-01
The purpose of this paper was to investigate the relaxation behavior of amorphous hesperetin (HRN), using dielectric spectroscopy, and assessment of its crystallization kinetics above glass transition temperature (Tg ). Amorphous HRN exhibited both local (β-) and global (α-) relaxations. β-Relaxation was observed below Tg , whereas α-relaxation prominently emerged above Tg . β-Relaxation was found to be of Johari-Goldstein type and was correlated with α-process by coupling model. Secondly, isothermal crystallization experiments were performed at 363 K (Tg + 16.5 K), 373 K (Tg + 26.5 K), and 383 K (Tg + 36.5 K). The kinetics of crystallization, obtained from the normalized dielectric strength, was modeled using the Avrami model. Havriliak-Negami (HN) shape parameters, αHN and αHN .βHN , were analyzed during the course of crystallization to understand the dynamics of amorphous phase during the emergence of crystallites. HN shape parameters indicated that long range (α-like) were motions affected to a greater extent than short range (β-like) motions during isothermal crystallization studies at all temperature conditions. The variable behavior of α-like motions at different isothermal crystallization temperatures was attributed to evolving crystallites with time and increase in electrical conductivity with temperature. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.
RH-temperature phase diagrams of hydrate forming deliquescent crystalline ingredients.
Allan, Matthew; Mauer, Lisa J
2017-12-01
Several common deliquescent crystalline food ingredients (including glucose and citric acid) are capable of forming crystal hydrate structures. The propensity of such crystals to hydrate/dehydrate or deliquesce is dependent on the environmental temperature and relative humidity (RH). As an anhydrous crystal converts to a crystal hydrate, water molecules internalize into the crystal structure resulting in different physical properties. Deliquescence is a solid-to-solution phase transformation. RH-temperature phase diagrams of the food ingredients alpha-d-glucose and citric acid, along with sodium sulfate, were produced using established and newly developed methods. Each phase diagram included hydrate and anhydrate deliquescence boundaries, the anhydrate-hydrate phase boundary, and the peritectic temperature (above which the hydrate was no longer stable). This is the first report of RH-temperature phase diagrams of glucose and citric acid, information which is beneficial for selecting storage and processing conditions to promote or avoid hydrate formation or loss and/or deliquescence. Copyright © 2017 Elsevier Ltd. All rights reserved.
Preparation of fine single crystals of magnetic superconductor RuSr2GdCu2O8-δ by partial melting
NASA Astrophysics Data System (ADS)
Yamaki, Kazuhiro; Bamba, Yoshihiro; Irie, Akinobu
2018-03-01
In this study, fine uniform RuSr2GdCu2O8-δ (RuGd-1212) single crystals have been successfully prepared by partial melting. Synthesis temperature could be lowered to a value not exceeding the decomposition temperature of RuGd-1212 using the Sr-Gd-Cu-O flux. The crystals grown by alumina boats are cubic, which coincides with the result of a previous study of RuGd-1212 single crystals using platinum crucibles. The single crystals were up to 15 × 15 × 15 µm3 in size and their lattice constants were consistent with those of polycrystalline samples reported previously. Although the present size of single crystals is not sufficient for measurements, the partial melting technique will be beneficial for future progress of research using RuGd-1212 single crystals. Appropriate nominal composition, sintering atmosphere, and temperature are essential factors for growing RuGd-1212 single crystals.
Theoretical study of the characteristics of a continuous wave iron-doped ZnSe laser
NASA Astrophysics Data System (ADS)
Pan, Qikun; Chen, Fei; Xie, Jijiang; Wang, Chunrui; He, Yang; Yu, Deyang; Zhang, Kuo
2018-03-01
A theoretical model describing the dynamic process of a continuous-wave Fe2+:ZnSe laser is presented. The influence of some of the operating parameters on the output characteristics of an Fe2+:ZnSe laser is studied in detail. The results indicate that the temperature rise of the Fe2+:ZnSe crystal is significant with the use of a high power pump laser, especially for a high doped concentration of crystal. The optimal crystal length increases with decreasing the doped concentration of crystal, so an Fe2+:ZnSe crystal with simultaneous doping during growth is an attractive choice, which usually has a low doped concentration and long length. The laser pumping threshold is almost stable at low temperatures, but increases exponentially with a working temperature in the range of 180 K to room temperature. The main reason for this phenomenon is the short upper level lifetime and serious thermal temperature rise when the working temperature is higher than 180 K. The calculated optimum output mirror transmittance is about 35% and the performance of a continuous-wave Fe2+:ZnSe laser is more efficient at a lower operating temperature.
High thermal stability and sluggish crystallization kinetics of high-entropy bulk metallic glasses
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yang, M.; Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon; Liu, X. J.
2016-06-28
Metallic glasses are metastable and their thermal stability is critical for practical applications, particularly at elevated temperatures. The conventional bulk metallic glasses (BMGs), though exhibiting high glass-forming ability (GFA), crystallize quickly when being heated to a temperature higher than their glass transition temperature. This problem may potentially be alleviated due to the recent developments of high-entropy (or multi-principle-element) bulk metallic glasses (HE-BMGs). In this work, we demonstrate that typical HE-BMGs, i.e., ZrTiHfCuNiBe and ZrTiCuNiBe, have higher kinetic stability, as compared with the benchmark glass Vitreoy1 (Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5}) with a similar chemical composition. The measured activation energymore » for glass transition and crystallization of the HE-BMGs is nearly twice that of Vitreloy 1. Moreover, the sluggish crystallization region ΔT{sub pl-pf}, defined as the temperature span between the last exothermic crystallization peak temperature T{sub pl} and the first crystallization exothermic peak temperature T{sub pf}, of all the HE-BMGs is much wider than that of Vitreloy 1. In addition, high-resolution transmission electron microscopy characterization of the crystallized products at different temperatures and the continuous heating transformation diagram which is proposed to estimate the lifetime at any temperature below the melting point further confirm high thermal stability of the HE-BMGs. Surprisingly, all the HE-BMGs show a small fragility value, which contradicts with their low GFA, suggesting that the underlying diffusion mechanism in the liquid and the solid of HE-BMGs is different.« less
Crystallization, flow and thermal histories of lunar and terrestrial compositions
NASA Technical Reports Server (NTRS)
Uhlmann, D. R.
1979-01-01
Contents: a kinetic treatment of glass formation; effects of nucleating heterogeneities on glass formation; glass formation under continuous cooling conditions; crystallization statistics; kinetics of crystal nucleation; diffusion controlled crystal growth; crystallization of lunar compositions; crystallization between solidus and liquidus; crystallization on reheating a glass; temperature distributions during crystallization; crystallization of anorthite and anorthite-albite compositions; effect of oxidation state on viscosity; diffusive creep and viscous flow; high temperature flow behavior of glass-forming liquids, a free volume interpretation; viscous flow behavior of lunar compositions; thermal history of orange soil material; breccias formation by viscous sintering; viscous sintering; thermal histories of breccias; solute partitioning and thermal history of lunar rocks; heat flow in impact melts; and thermal histories of olivines.
Controlling the physical form of mannitol in freeze-dried systems.
Mehta, Mehak; Bhardwaj, Sunny P; Suryanarayanan, Raj
2013-10-01
A potential drawback with the use of mannitol as a bulking agent is its existence as mannitol hemihydrate (MHH; C₆H₁₄O₆·0.5H₂O) in the lyophile. Once formed during freeze-drying, MHH dehydration may require secondary drying under aggressive conditions which can be detrimental to the stability of thermolabile components. If MHH is retained in the lyophile, the water released by MHH dehydration during storage has the potential to cause product instability. We systematically identified the conditions under which anhydrous mannitol and MHH crystallized in frozen systems with the goal of preventing MHH formation during freeze-drying. When mannitol solutions were cooled, the temperature of solute crystallization was the determinant of the physical form of mannitol. Based on low temperature X-ray diffractometry (using both laboratory and synchrotron sources), MHH formation was observed when solute crystallization occurred at temperatures ≤ -20 °C, while anhydrous mannitol crystallized at temperatures ≤ -10 °C. The transition temperature (anhydrate - MHH) appears to be ∼-15 °C. The use of a freeze-dryer with controlled ice nucleation technology enabled anhydrous mannitol crystallization at ∼-5 °C. Thus, ice crystallization followed by annealing at temperatures ≤ -10 °C can be an effective strategy to prevent MHH formation. Copyright © 2013 Elsevier B.V. All rights reserved.
75 FR 18047 - Amendment of Low Altitude Area Navigation Route T-254; Houston, TX
Federal Register 2010, 2011, 2012, 2013, 2014
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...-0015; Airspace Docket No. 09-ASW-18] RIN 2120-AA66 Amendment of Low Altitude Area Navigation Route T... action amends low altitude Area Navigation (RNAV) route T-254 in the Houston, TX, terminal area by... the College Station, TX, VORTAC. The FAA is taking this action to eliminate a portion of T-254 that is...
77 FR 40945 - Qualification of Drivers; Exemption Applications; Vision
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USDA-ARS?s Scientific Manuscript database
The draft genome sequence of “Candidatus Liberibacter asiaticus” strain TX2351 collected from ACP in South Texas has been determined. The TX2351 genome is 1,252,043 bp in size with a 36.5% G+C content, encoding 1,184 predicted open reading frames and 51 RNA genes....
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Binding Affinity of Glycoconjugates to BACILLUS Spores and Toxins
NASA Astrophysics Data System (ADS)
Rasol, Aveen; Eassa, Souzan; Tarasenko, Olga
2010-04-01
Early recognition of Bacillus cereus group species is important since they can cause food-borne illnesses and deadly diseases in humans. Glycoconjugates (GCs) are carbohydrates covalently linked to non-sugar moieties including lipids, proteins or other entities. GCs are involved in recognition and signaling processes intrinsic to biochemical functions in cells. They also stimulate cell-cell adhesion and subsequent recognition and activation of receptors. We have demonstrated that GCs are involved in Bacillus cereus spore recognition. In the present study, we have investigated whether GCs possess the ability to bind and recognize B. cereus spores and Bacillus anthracis recombinant single toxins (sTX) and complex toxins (cTX). The affinity of GCs to spores + sTX and spores + cTX toxins was studied in the binding essay. Our results demonstrated that GC9 and GC10 were able to selectively bind to B. cereus spores and B. anthracis toxins. Different binding affinities for GCs were found toward Bacillus cereus spores + sTX and spores + cTX. Dilution of GCs does not impede the recognition and binding. Developed method provides a tool for simultaneous recognition and targeting of spores, bacteria toxins, and/or other entities.
Morimoto, H; Matsuda, A; Ohori, M; Fujii, T
1996-06-01
We examined the effects of Ca2+ channel antagonists on various respiratory reactions induced by the activation of capsaicin-sensitive afferent sensory nerves. Intravenous (i.v.) injection of the N-type Ca2+ channel antagonist omega-conotoxin GVIA (CgTX) (1-20 micrograms/kg) dose-dependently inhibited capsaicin-induced guinea pig bronchoconstriction, whereas i.v. administration of the L-type antagonist nicardipine (100 micrograms/kg), the P-type antagonist omega-agatoxin IVA (AgaTX) (20 micrograms/kg) or the OPQ family-type antagonist omega-conotoxin MVIIC (CmTX) (20 micrograms/kg) had no effect. However, CgTX (20 micrograms/kg) failed to inhibit substance P-induced guinea pig bronchoconstriction. CgTX (20 micrograms/kg) significantly inhibited cigarette smoke-induced guinea pig tracheal plasma extravasation, but not the substance P-induced reaction. CgTX also reduced electrical field stimulation-induced guinea pig bronchial smooth muscle contraction (0.01-10 microM) and capsaicin-induced substance P-like immunoreactivity release from guinea pig lung (0.14 microM). This evidence suggests that N-type Ca2+ channels modulate tachykinin release from capsaicin-sensitive afferent sensory nerve endings in guinea pig airway tissue.
Maung-Maung-Thwin; Gopalakrishnakone, P; Yuen, R; Tan, C H
1996-02-01
Daboiatoxin (DbTx), the PLA2 neurotoxin from Daboia russelli siamensis venom, was shown to bind specifically and saturably to rat cerebrocortical synaptosomes and synaptic membrane fragments. Two families of binding sites were detected by equilibrium binding analysis in the presence and absence of Ca2+. Scatchard analysis of biphasic plateaus revealed Kdl 5 nM and Bmax1, 6 pmoles/mg protein, and Kd2 80 nM and Bmax2 20 pmoles/mg protein, respectively, for the high- and low-affinity binding sites. The binding of 125I-DbTx to synaptosomes did not show marked dependence on Ca2+, Mg2+, Co2+ and Sr2+. Native DbTx was the only strong competitor to 125I-DbTx synaptosomal binding (IC50 12.5 nM, KI 5.5 nM). Two other crotalid PLA2 neurotoxins, crotoxin CB and mojave toxin basic subunit, and nontoxic C. Atrox PLA2 enzyme, were relatively weaker inhibitors, while two viperid PLA2 neurotoxins, ammodytoxin A and VRV PL V, were very weak inhibitors. Crotoxin CA was a poor inhibitor even at microM concentrations, whereas no inhibitory effect at all was observed with crotoxin CACB, ammodytoxin C, VRV PL VIIIa, taipoxin, beta-bungarotoxin, or with PLA2 enzymes from N. naja venom, E. schistosa venom, bee venom and porcine pancreas. All other pharmacologically active ligands examined (epinephrine, norepinephrine, histamine, choline, dopamine, serotonin, GABA, naloxone, WB-4101, atropine, hexamethonium and alpha-bun-garotoxin) also failed to interfere with 125I-DbTx binding. As those competitors that showed partial inhibition were effective only at microM concentration range compared to the Kd (5 nM) of 125I-DbTx synaptosomal binding, DbTx could well recognize a different neuronal binding site. Rabbit anti-DbTx polyclonal antisera completely blocked the specific binding. When a range of Ca2+ and K+ channels modulators were examined, Ca2+ channel blockers (omega-conotoxins GVIA and MVIIC, taicatoxin, calciseptine and nitrendiprene) did not affect the binding even at high concentrations, while charybdotoxin was the only K+ channel effector that could partially displace 125I-DbTx synaptosomal binding amongst the K+ channel blockers tested (apamin, dendrotoxin-I, iberiotoxin, MCD-peptide, 4-aminopyridine and tetraethylammonium), suggesting that neither K+ nor Ca2+ channels are associated with DbTx binding sites.
van Grootel, Robert J; Buchner, Rob; Wismeijer, Daniël; van der Glas, Hilbert W
2017-02-10
Temporomandibular Disorders (TMD) may be characterized by pain and restricted jaw movements. In the absence of somatic factors in the temporomandibular joint, mainly myogenous, psychobiological, and psychosocial factors may be involved in the aetiology of myogenous TMD. An occlusal appliance (splint) is commonly used as a basic therapy of the dental practice. Alternatively, a type of physiotherapy which includes, apart from massage of sore muscles, aspects of cognitive-behavioural therapy might be a basic therapy for myogenous TMD. Treatment outcome of physiotherapy (Ph-Tx) was evaluated in comparison to that of splint therapy (Sp-Tx), using the index Treatment Duration Control (TDC) that enabled a randomized controlled trial with, comparable to clinical care, therapy-and-patient-specific treatment durations. Seventy-two patients were randomly assigned to either Ph-Tx or Sp-Tx, with an intended treatment duration between 10 and 21 or 12 and 30 weeks respectively. Using TDC, the clinician controlled treatment duration and the number of visits needed. A blinded assessor recorded anamnestic and clinical data to determine TDC-values following treatment and a 1-year follow-up, yielding success rate (SR) and effectiveness (mean TDC) as treatment outcomes. Cohen's d, was determined for pain intensity. Overall SR for stepped-care was assessed in a theoretical model, i.e. a second of the two studied therapies was applied if the first treatment was unsuccessful, and the effect of therapy sequence and difference in success rates was examined. SR and effectiveness were similar for Ph-Tx and Sp-Tx (long-term SR: 51-60%; TDC: -0.512- -0.575). Cohen's d was 0.86 (Ph-Tx) and 1.39 (Sp-Tx). Treatment duration was shorter for Ph-Tx (on average 10.4 weeks less; p < 0.001). Sp-Tx needed 7.1 less visits (p < 0.001). Physiotherapy may be preferred as initial therapy over occlusal splint therapy in stepped-care of myogenous TMD. With a similar SR and effectiveness, physiotherapy has a shorter duration. Thus patients whose initial physiotherapy is unsuccessful can continue earlier with subsequent treatment. The stepped-care model reinforces the conclusion on therapy preference as the overall SR hardly depends on therapy sequence. isrctn.com/ISRCTN17469828 . Retrospectively registered: 11/11/2016.
Aluminum induced crystallization of amorphous Ge thin films on insulating substrate
DOE Office of Scientific and Technical Information (OSTI.GOV)
Singh, Ch. Kishan, E-mail: kisn@igcar.gov.in; Tah, T.; Sunitha, D. T.
2016-05-23
Aluminium (metal) induced crystallization of amorphous Ge in bilayer and multilayer Ge/Al thin films deposited on quartz substrate at temperature well below the crystallization temperature of bulk Ge is reported. The crystallization of poly-Ge proceeds via formations of dendritic crystalline Ge grains in the Al matrix. The observed phases were characterized by Raman spectroscopy and X-ray diffraction. The microstructure of Al thin film layer was found to have a profound influence on such crystallization process and formation of dendritic grains.
Phase determinations and crystal growth of Pb 2KNb 5O 15 (PKN)
NASA Astrophysics Data System (ADS)
Kramer, W. E.; Roland, G. W.
1982-07-01
Two problems must be addressed before good quality crystals of Pb 2KNb 5O 15 (PKN) can be grown: first, the compound does not melt congruently and therefore growth must be slow to avoid inclusions in the crystal; and second, cracking of crystals occurs during cooling due to anisotropic behavior of the thermal expansion coefficients at the Curie temperature. Extremely slow cooling in a uniform temperature gradient is necessary to get good quality, uncracked crystals.
NASA Astrophysics Data System (ADS)
Sheth, Swapnil Suhas
Narrow molecular weight fractions of poly(epsilon-caprolactone) were successfully obtained using the successive precipitation fractionation technique with toluene/n-heptane as a solvent/nonsolvent pair. Calorimetric studies of the melting behavior of fractions that were crystallized either isothermally or under constant cooling rate conditions suggested that the isothermal crystallization of the samples should be used for a proper evaluation of the molecular weight dependence of the observed melting temperature and degree of crystallinity in PCL. The molecular weight and temperature dependence of the spherulitic growth rate of fractions was studied in the context of the Lauritzen-Hoffman two-phase model and the Strobl three-phase model of polymer crystallization. The zero-growth rate temperatures, determined from spherulitic growth rates using four different methods, are consistent with each other and increase with chain length. The concomitant increase in the apparent secondary nucleation constant was attributed to two factors. First, for longer chains there is an increase in the probability that crystalline stems belong to loose chain-folds, hence, an increase in fold surface free energy. It is speculated that the increase in loose folding and resulting decrease in crystallinity with increasing chain length are associated with the ester group registration requirement in PCL crystals. The second contribution to the apparent nucleation constant arises from chain friction associated with segmental transport across the melt/crystal interface. These factors were responsible for the much stronger chain length dependence of spherulitic growth rates at fixed undercooling observed here with PCL than previously reported for PE and PEO. In the case of PCL, the scaling exponent associated with the chain length dependence of spherulitic growth rates exceeds the upper theoretical bound of 2 predicted from the Brochard- DeGennes chain pullout model. Observation that zero-growth and equilibrium melting temperature values are identical with each other within the uncertainty of their determinations casts serious doubt on the validity of Strobl three-phase model. A novel method is proposed to determine the Porod constant necessary to extrapolate the small angle X-ray scattering intensity data to large scattering vectors. The one-dimensional correlation function determined using this Porod constant yielded the values of lamellar crystal thickness, which were similar to these estimated using the Hosemann-Bagchi Paracrystalline Lattice model. The temperature dependence of the lamellar crystal thickness was consistent with both LH and the Strobl model of polymer crystallization. However, in contrast to the predictions of Strobl's model, the value of the mesomorph-to-crystal equilibrium transition temperature was very close to the zero-growth temperature. Moreover, the lateral block sizes (obtained using wide angle X-ray diffraction) and the lamellar thicknesses were not found to be controlled by the mesomorph-to-crystal equilibrium transition temperature. Hence, we concluded that the crystallization of PCL is not mediated by a mesophase. Metallocene-catalyzed linear low-density (m-LLDPE with 3.4 mol% 1-octene) and conventional low-density (LDPE) polyethylene blends of different compositions were investigated for their melt-state miscibility and concurrent crystallization tendency. Differential scanning calorimetric studies and morphological studies using atomic force microscopy confirm that these blends are miscible in the melt-state for all compositions. LDPE chains are found to crystallize concurrently with m-LLDPE chains during cooling in the m-LLDPE crystallization temperature range. While the extent of concurrent crystallization was found to be optimal in .. .. iv blends with highest m-LLDPE content studied, strong evidence was uncovered for the existence of a saturation effect in the concurrent crystallization behavior. This observation leads us to suggest that co-crystallization, rather than mere concurrent crystallization, of LDPE with m- LLDPE can indeed take place. Matching of the respective sequence length distributions in LDPE and m-LLDPE is suggested to control the extent of co-crystallization.
NASA Astrophysics Data System (ADS)
Mitsuya, Takuro; Takahashi, Kyohei; Nagashima, Kazushige
2014-09-01
"Storm glass" is a hermetically sealed glass tube containing a solution of camphor. In 19th-century England, the pattern and quantity of the crystals were observed and interpreted as a weather forecasting tool. In the present study, the appearance of camphor crystals under cyclic temperature change was studied in three sample solutions, the storm glass solution (quinary system), camphor-ethanol-water (ternary system), and camphor-ethanol (binary system), to elucidate the effect of components in the storm glass on the appearance of camphor crystals. Equilibrium temperatures of camphor crystals as a function of the camphor concentration were also obtained to estimate the quantity of camphor crystals precipitated in the solutions. During the temperature cycles, the crystal height increased and decreased. The ranges (local maxima and minima) of crystal heights gradually decreased to approximately a constant range. Not only the crystal height but also the amplitude of the height variation in the quinary and ternary systems were much larger than those in the binary system, although the estimated weights of crystals precipitated in the quinary and ternary systems were smaller than that in the binary system. This fact resulted from the formation of dendrites in the quinary and ternary systems, which caused high porosity of sedimented crystals.
Xu, Kailin; Xiong, Xinnuo; Guo, Liuqi; Wang, Lili; Li, Shanshan; Tang, Peixiao; Yan, Jin; Wu, Di; Li, Hui
2015-12-01
Levetiracetam (LEV) crystals were prepared using different solvents at different temperatures. The LEV crystals were systematically characterized by X-ray powder diffraction (XRPD) and morphological analysis. The results indicated that many kinds of crystal habits exist in a solid form of LEV. To investigate the effects of LEV concentration, crystallization temperature, and crystallization type on crystallization and solid phase transformation of LEV, multiple methods were performed for LEV aqueous solution to determine if a new solid form exists in solid-state LEV. However, XRPD data demonstrate that the LEV solid forms possess same spatial arrangements that are similar to the original solid form. This result indicates that the LEV concentration, crystallization temperature, and crystallization type in aqueous solution have no influence on the crystallization and solid phase transformation of LEV. Moreover, crystallization by sublimation, melt cooling, and quench cooling, as well as mechanical effect, did not result in the formation of new LEV solid state. During melt cooling, the transformation of solid form LEV is a direct process from melting amorphous phase to the original LEV crystal phase, and the conversion rate is very quick. In addition, stability investigation manifested that LEV solid state is very stable under various conditions. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
NASA Astrophysics Data System (ADS)
Dong, Xiaowan; Zhang, Yadi; Ding, Bing; Hao, Xiaodong; Dou, Hui; Zhang, Xiaogang
2018-06-01
Multifarious layered materials have received extensive concern in the field of energy storage due to their distinctive two-dimensional (2D) structure. However, the natural tendency to be re-superimposed and the inherent disadvantages of a single 2D material significantly limit their performance. In this work, the delaminated Ti3C2Tx (d-Ti3C2Tx)/cobalt-aluminum layered double hydroxide (Ti3C2Tx/CoAl-LDH) composites are prepared by layer-by-layer self-assembly driven by electrostatic interaction. The alternate Ti3C2Tx and CoAl-LDH layers prevent each other from restacking and the obtained Ti3C2Tx/CoAl-LDH heterostructure combine the advantages of high electron conductivity of Ti3C2Tx and high electrochemical activity of CoAl-LDH, thus effectively improving the electrochemical reactivity of electrode materials and accelerating the kinetics of Faraday reaction. As a consequence, as a cathode for alkaline hybrid battery, the Ti3C2Tx/CoAl-LDH electrode exhibits a high specific capacity of 106 mAh g-1 at a current density of 0.5 A g-1 and excellent rate capability (78% at 10 A g-1), with an excellent cycling stability of 90% retention after 5000 cycles at 4 A g-1. This work provides an alternative route to design advanced 2D electrode materials, thus exploiting their full potentials for alkaline hybrid batteries.
Chen, Sujuan; Zhu, Yinbiao; Yang, Da; Yang, Yang; Shi, Shaohua; Qin, Tao; Peng, Daxin; Liu, Xiufan
2017-01-01
H9N2 avian influenza virus is a zoonotic agent with a broad host range that can contribute genetic information to H5 or H7N9 subtype viruses, which are significant threats to both humans and birds. Thus, there is a great need for a vaccine to control H9N2 avian influenza. Three mutant viruses of an H9N2 virus A/chicken/Taixing/10/2010 (rTX-NS1-73, rTX-NS1-100, and rTX-NS1-128) were constructed with different NS1 gene truncations and confirmed by western blot analysis. The genetic stability, pathogenicity, transmissibility, and host immune responses toward these mutants were evaluated. The mutant virus rTX-NS1-128 exhibited the most attenuated phenotype and lost transmissibility. The expression levels of interleukin 12 in the nasal and tracheal tissues from chickens immunized with rTX-NS1-128 were significantly upregulated on day 3 post-immunization and the IgA and IgG antibody levels were significantly increased on days 7, 14, and 21 post-immunization when compared to chickens that received an inactivated vaccine. rTX-NS1-128 also protected chickens from challenge by homologous and heterologous H9N2 avian influenza viruses. The results indicate that rTX-NS1-128 can be used as a potential live-attenuated vaccine against H9N2 avian influenza.
Cellular transplants in amyotrophic lateral sclerosis patients: an observational study.
Gamez, Josep; Carmona, Francesc; Raguer, Nuria; Ferrer-Sancho, Jaume; Martín-Henao, Gregorio A; Martí-Beltrán, Sergi; Badia, Merce; Gratacós, Margarita; Rodriguez-Gónzalez, Esther; Seoane, Jose Luis; Pallero-Castillo, Mercedes; Burgos, Rosa; Puiggros, Carolina; Pasarin, Alejandro; Bori-Fortuny, Inmaculada
2010-09-01
Cytotherapy is a promising option for neurodegenerative disease treatment. Because of the fatal prognosis and imperative need for effective treatment, amyotrophic lateral sclerosis (ALS) patients request this therapy before its effectiveness has been verified. The increase in clinics offering cytotherapies but providing little scientific information has prompted considerable medical tourism. We present an observational study of Spanish ALS patients receiving cytotherapy, analyzing the experiences arising from the treatment (TX) and considering two progression markers, FVC and ALSFRS-R. Twelve ALS patients with a mean age of 48.6 years (SD 12.8) received cytotherapy 26.9 months (SD 15.8) after clinical onset. ALSFRS-R and FVC at TX were 32.3 (SD 6.8) and 63.4% (SD 15.3), respectively. TX involved transplants of olfactory ensheathing cells in three patients, and autologous mesenchymal stromal cells in the remainder. One patient died 33 months post-TX after surviving for 49 months. Five required mechanical non-invasive home ventilation 7.4 months post-TX. Two required invasive ventilation 13 months post-TX. Five patients needed gastrostomy feeding 23.3 months post-TX. Survival between clinical onset and the study end date was 50 months (SD 17.2). No significant adverse events or changes in the decline of FVC and ALSFRS-R compared with the disease's natural history were observed. Our observations suggest that these therapies do not halt the course of the disease. Cytotherapy cannot yet be considered a curative treatment for ALS.
Thromboxane Formation Assay to Identify High On-Treatment Platelet Reactivity to Aspirin.
Mohring, Annemarie; Piayda, Kerstin; Dannenberg, Lisa; Zako, Saif; Schneider, Theresa; Bartkowski, Kirsten; Levkau, Bodo; Zeus, Tobias; Kelm, Malte; Hohlfeld, Thomas; Polzin, Amin
2017-01-01
Platelet inhibition by aspirin is indispensable in the secondary prevention of cardiovascular events. Nevertheless, impaired aspirin antiplatelet effects (high on-treatment platelet reactivity [HTPR]) are frequent. This is associated with an enhanced risk of cardiovascular events. The current gold standard to evaluate platelet hyper-reactivity despite aspirin intake is the light-transmittance aggregometry (LTA). However, pharmacologically, the most specific test is the measurement of arachidonic acid (AA)-induced thromboxane (TX) B2 formation. Currently, the optimal cut-off to define HTPR to aspirin by inhibition of TX formation is not known. Therefore, in this pilot study, we aimed to calculate a TX formation cut-off value to detect HTPR defined by the current gold standard LTA. We measured platelet function in 2,507 samples. AA-induced TX formation by ELISA and AA-induced LTA were used to measure aspirin antiplatelet effects. TX formation correlated nonlinearly with the maximum of aggregation in the AA-induced LTA (Spearman's rho R = 0.7396; 95% CI 0.7208-0.7573, p < 0.0001). Receiver operating characteristic analysis and Youden's J statistics revealed 209.8 ng/mL as the optimal cut-off value to detect HTPR to aspirin with the TX ELISA (area under the curve: 0.92, p < 0.0001, sensitivity of 82.7%, specificity of 90.3%). In summary, TX formation ELISA is reliable in detecting HTPR to aspirin. The calculated cut-off level needs to be tested in trials with clinical end points. © 2017 S. Karger AG, Basel.
NASA Technical Reports Server (NTRS)
1996-01-01
Because of their superior high-temperature properties, gas generator turbine airfoils made of single-crystal, nickel-base superalloys are fast becoming the standard equipment on today's advanced, high-performance aerospace engines. The increased temperature capabilities of these airfoils has allowed for a significant increase in the operating temperatures in turbine sections, resulting in superior propulsion performance and greater efficiencies. However, the previously developed methodologies for life-prediction models are based on experience with polycrystalline alloys and may not be applicable to single-crystal alloys under certain operating conditions. One of the main areas where behavior differences between single-crystal and polycrystalline alloys are readily apparent is subcritical fatigue crack growth (FCG). The NASA Lewis Research Center's work in this area enables accurate prediction of the subcritical fatigue crack growth behavior in single-crystal, nickel-based superalloys at elevated temperatures.
NASA Astrophysics Data System (ADS)
Král, Robert
2012-12-01
Suitable conditions for growth of high quality single crystals of ternary alkali lead halides prepared by a Bridgman method were explored using direct observation of a crystal/melt interface when pulling an ampoule out of a furnace, deliberated striations' induction and measurement of a temperature field in the filled ampoule in the vertical Bridgman arrangement, as model compounds lead chloride and ternary rubidium lead bromide were used. By direct observation only position of the crystal/melt interface was markedly determined, while by induced striations both the position and the shape of the interface were visualized but their contrast had to be intensified by adding admixtures. Performed temperature measurements in the filled ampoule brought both a view of temperature field in the 3D radial symmetry and basic data for comparison of a real temperature field with those obtained by projected modeling.
Aronhime, Natan; Zoghlin, Eli; Keylin, Vladimir; ...
2017-09-26
Fe-Ni based metal amorphous nanocomposites (MANCs) are investigated in the pseudo-binary alloys (Fe 100–xNi x) 80Nb 4Si 2B 14. To optimize the soft magnetic properties of the nanocomposites, primary and secondary crystallization kinetics must be understood. As such, primary and secondary crystallization temperatures are determined by differential scanning calorimetry, and activation energies are calculated, along with the resulting crystalline phases. Time-temperature-transformation diagrams for primary and secondary crystallization in (Fe 70Ni 30) 80Nb 4Si 2B 14 are presented. Saturation magnetization and Curie temperature are determined. In conclusion, the shape of magnetization vs. time curves for (Fe 30Ni 70) 80Nb 4Si 2Bmore » 14 at various temperatures suggest that the secondary crystal product often consumes some of the primary crystalline product.« less
Electrical and thermoluminescence properties of γ-irradiated La2CuO4 crystals
NASA Astrophysics Data System (ADS)
El-Kolaly, M. A.; Abd El-Kader, H. I.; Kassem, M. E.
1994-12-01
Measurements of the electrical properties of unirradiated as well as ?-irradiated La2CuO4 crystals were carried out at different temperatures in the frequency range of 0.1-100 kHz. Thermoluminescence (TL) studies were also performed on such crystals in the temperature range of 300-600K. The conductivity of the unirradiated La2CuO4 crystals were found to obey the power law frequency dependence at each measured temperature below the transition temperature (Tc = 450K). The activation energies for conduction and dielectric relaxation time have been calculated. The TL response and the dc resistance were found to increase with ?-irradiation dose up to 9-10 kGy. The results showed that the ferroelastic domain walls of La2CuO4 crystal as well as its TL traps are sensitive to ?-raditaion. This material can be used in radiation measurements in the range 225 Gy-10 kGy.
NASA Astrophysics Data System (ADS)
Khademian, Ali; Jampani, Sai Lakshman; Truscott, Matthew; Jayaraj, Anooja; Shiner, David
2017-04-01
We have reported 81.5% efficiency in generating 500 mW of blue at 486 nm by second harmonic generation (SHG) from the IR, using a periodically poled Lithium Tantalate (PPSLT) crystal. Initially a total cavity loss of 0.65% was observed. We developed techniques for careful measurement of individual losses such as scattering and absorption in the crystal and mirrors, polarization misalignment caused by the crystal and back reflection from the periodically poled boundaries of crystal. We have replaced the crystal with a tilted periodically poled crystal. This eliminated the reflection loss, but scattering in the crystal, we speculate from the MgO doping, is still causing enough feedback to destabilize the IR source. We are also replacing cavity mirrors with ultra-low loss sputtered mirrors to minimize their contribution to loss. Crystal lifetime at different blue power levels is being investigated. In our setup a mixed signal processer (MSP) is used for cavity locking and temperature stabilizing. Once MSP is programed by a computer interface, it can be installed inside the cavity housing, making the laser source standalone and self-sufficient. We have been able to stabilize and lock the laser cavity length, the temperature of the IR laser source, the temperature of fiber Bragg grating (FBG), and the temperature of the nonlinear crystal using the MSP, matching the performance of high end commercial temperature controllers and lock-in amplifiers. Our recent progress and improvements will be presented. This work is supported by NSF award 1404498.
The solubility of hen egg-white lysozyme
NASA Technical Reports Server (NTRS)
Howard, Sandra B.; Twigg, Pamela J.; Baird, James K.; Meehan, Edward J.
1988-01-01
The equilibrium solubility of chicken egg-white lysozyme in the presence of crystalline solid state was determined as a function of NaCl concentration, pH, and temperature. The solubility curves obtained represent a region of the lysozyme phase diagram. This diagram makes it possible to determine the supersaturation of a given set of conditions or to achieve identical supersaturations by different combinations of parameters. The temperature dependence of the solubility permits the evaluation of Delta-H of crystallization. The data indicate a negative heat of crystallization for the tetragonal crystal form but a positive heat of crystallization for the high-temperature orthorhombic form.
Defect-induced local variation of crystal phase transition temperature in metal-halide perovskites.
Dobrovolsky, Alexander; Merdasa, Aboma; Unger, Eva L; Yartsev, Arkady; Scheblykin, Ivan G
2017-06-26
Solution-processed organometal halide perovskites are hybrid crystalline semiconductors highly interesting for low-cost and efficient optoelectronics. Their properties are dependent on the crystal structure. Literature shows a variety of crystal phase transition temperatures and often a spread of the transition over tens of degrees Kelvin. We explain this inconsistency by demonstrating that the temperature of the tetragonal-to-orthorhombic phase transition in methylammonium lead triiodide depends on the concentration and nature of local defects. Phase transition in individual nanowires was studied by photoluminescence microspectroscopy and super-resolution imaging. We propose that upon cooling from 160 to 140 K, domains of the crystal containing fewer defects stay in the tetragonal phase longer than highly defected domains that readily transform to the high bandgap orthorhombic phase at higher temperatures. The existence of relatively pure tetragonal domains during the phase transition leads to drastic photoluminescence enhancement, which is inhomogeneously distributed across perovskite microcrystals.Understanding crystal phase transition in materials is of fundamental importance. Using luminescence spectroscopy and super-resolution imaging, Dobrovolsky et al. study the transition from the tetragonal to orthorhombic crystal phase in methylammonium lead triiodide nanowires at low temperature.
Growth of binary organic NLO crystals: m.NA-p.NA and m.NA-CNA system
NASA Technical Reports Server (NTRS)
Singh, N. B.; Henningsen, T.; Hopkins, R. H.; Mazelsky, R.
1993-01-01
Experiments were carried out to grow 3.Nitroaniline (m.NA) crystals doped with 4.Nitroaniline (p.NA) and 2.chloro 4.Nitroaniline (CNA). The measured undercooling for m.NA, p.NA, and CNA were 0.21 tm K, 0.23 tm K, and 0.35 tm K respectively, where tm represents the melting temperature of the pure component. Because of the crystals' large heat of fusion and large undercooling, it was not possible to grow good quality crystals with low thermal gradients. In the conventional two-zone Bridgman furnace we had to raise the temperature of the hot zone above the decomposition temperature of CNA, p.NA, and m.NA to achieve the desired thermal gradient. To avoid decomposition, we used an unconventional Bridgman furnace. Two immiscible liquids, silicone oil and ethylene glycol, were used to build a special two-zone Bridgman furnace. A temperature gradient of 18 K/cm was achieved without exceeding the decomposition temperature of the crystal. The binary crystals, m.NA-p.NA and m.NA-CNA, were grown in centimeter size in this furnace. X-ray and optical characterization showed good optical quality.
Low temperature growth of Ga 1- xIn xP bulk crystals from InSb-rich melt
NASA Astrophysics Data System (ADS)
Gennett, A.; Lewis, D.; Dutta, P. S.
2010-04-01
Bulk growth of phosphorus and arsenic based ternary III-V semiconductor crystals using pseudo-binary melts such as GaP-InP, GaP-GaAs, AlAs-GaAs, etc. is significantly challenging due to the high vapor pressures of group V species in conjunction with slow growth rates and the need for melt replenishment and mixing during growth. Lowering the growth temperature is desirable such that the vapor pressures of P and As can be easily handled. Low growth temperatures could be achieved by using Ga or In rich solutions. However, this approach is less attractive for growing bulk crystals due to several experimental difficulties including sticking of the growth solution to the crucible wall and to the grown crystal, making it challenging for crystal extraction. Growth of ternary crystals from low temperature quaternary melts has been found to be attractive. In this paper, we will present a new method for the growth of Ga 1- xIn xP from InSb rich Ga 1- xIn xP ySb 1- y melts at low growth temperatures in the range of 800-1050 °C. Thermodynamic phase diagrams calculated at various temperatures using a Gibbs free energy minimization software and materials databases commercially available from Thermo-Calc software will be presented along with experimental validation for Ga 1- xIn xP crystals grown at 1000 °C.
Masunaga, Shin-Ichiro; Nagasawa, Hideko; Hiraoka, Masamitsu; Sakurai, Yoshinori; Uto, Yoshihiro; Hori, Hitoshi; Nagata, Kenji; Suzuki, Minoru; Maruhashi, Akira; Kinashi, Yuko; Ono, Koji
2004-01-01
It is difficult to deliver a therapeutic amount of 10B from conventional 10B-carriers for boron neutron capture therapy (BNCT) throughout the target tumors, especially into the intratumor hypoxic cells which have low uptake capacities. We evaluated the usefulness of 5 new 10B-compounds (TX-2041, TX-2042, TX-2058, TX-2059 and TX-2060) as 10B-carriers in BNCT. They are 2-nitroimidazole-sodium borocaptate-10B (BSH) conjugates, that is, hybrid compounds that have both a hypoxic tumor cell sensitizing unit under gamma-ray irradiation, 2-nitroimidazoles and a thermal neutron-sensitizing unit, BSH. The 5 new compounds were administered to SCC VII tumor-bearing mice intraperitoneally. As a control, BSH was also administered in the same manner. Then, the 10B concentrations in the tumors and normal tissues were measured by gamma-ray spectrometry. Based on the data of the pharmacokinetics analyses, TX-2060 was chosen for a subsequent tumor-irradiation study. SCC VII tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumors, then treated with TX-2060 or BSH in the same manner as in the pharmacokinetics analyses. To obtain similar intratumor 10B concentrations during radiation exposure, irradiation with thermal neutrons or gamma-rays was started from 60 min after administration of the 10B-carrier. Right after irradiation, the tumors were excised, minced and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU-labelling (= quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU. The clonogenic cell survival was also determined in mice given no BrdU. 10B distribution analyses in tumors, muscles, blood and liver indicated that TX-2060 has the most favorable characteristics for concentrating a sufficient amount of 10B in tumors and maintaining a high enough 10B concentration during irradiation. In addition, TX-2060 had a significantly stronger radio-sensitization effect with reactor thermal neutron beams than BSH on both total and Q cells in solid tumors. Further, TX-2060 clearly exhibited a radio-sensitization effect with gamma-rays, not only on total cells but also on Q and hypoxic tumor cells, which was not achieved by BSH. 10B-carrier, with a gamma-ray-sensitizing effect on tumor cells as well as the potential to keep 10B in tumors and sensitize tumor cells more markedly than conventional 10B-carriers, such as TX-2060, is a promising candidate for use in BNCT.
35 GHz Measurements of CO2 Crystals for Simulating Observations of the Martian Polar Caps
NASA Technical Reports Server (NTRS)
Foster, J. L.; Chang, A. T. C.; Hall, D. K.; Tait, A. B.; Barton, J. S.
1998-01-01
In order to learn more about the Martian polar caps, it is important to compare and contrast the behavior of both frozen H2O and CO2 in different parts of the electromagnetic spectrum. Relatively little attention has been given, thus far, to observing the thermal microwave part of the spectrum. In this experiment, passive microwave radiation emanating from within a 33 cm snowpack was measured with a 35 GHz hand-held radiometer, and in addition to the natural snow measurements, the radiometer was used to measure the microwave emission and scattering from layers of manufactured CO2 (dry ice). A 1 m x 2 m plate of aluminum sheet metal was positioned beneath the natural snow so that microwave emissions from the underlying soil layers would be minimized. Compared to the natural snow crystals, results for the dry ice layers exhibit lower' microwave brightness temperatures for similar thicknesses, regardless of the incidence angle of the radiometer. For example, at 50 degree H (horizontal polarization) and with a covering of 21 cm of snow and 18 cm of dry ice, the brightness temperatures were 150 K and 76 K, respectively. When the snow depth was 33 cm, the brightness temperature was 144 K, and when the total thickness of the dry ice was 27 cm, the brightness temperature was 86 K. The lower brightness temperatures are due to a combination of the lower physical temperature and the larger crystal sizes of the commercial CO2 Crystals compared to the snow crystals. As the crystal size approaches the size of the microwave wavelength, it scatters microwave radiation more effectively, thus lowering the brightness temperature. The dry ice crystals in this experiment were about an order of magnitude larger than the snow crystals and three orders of magnitude larger than the CO2 Crystals produced in the cold stage of a scanning electron microscope. Spreading soil, approximately 2 mm in thickness, on the dry ice appeared to have no effect on the brightness temperatures.
NASA Technical Reports Server (NTRS)
Tan, Benjamin
1995-01-01
Using thermochromatic liquid crystal to measure surface temperature, an automated transient method with time-varying free-stream temperature is developed to determine local heat transfer coefficients. By allowing the free-stream temperature to vary with time, the need for complicated mechanical components to achieve a step temperature change is eliminated, and by using the thermochromatic liquid crystals as temperature indicators, the labor intensive task of installing many thermocouples is omitted. Bias associated with human perception of the transition of the thermochromatic liquid crystal is eliminated by using a high speed digital camera and a computer. The method is validated by comparisons with results obtained by the steady-state method for a circular Jet impinging on a flat plate. Several factors affecting the accuracy of the method are evaluated.
Crystallization Kinetics of Barium and Strontium Aluminosilicate Glasses of Feldspar Composition
NASA Technical Reports Server (NTRS)
Hyatt, Mark J.; Bansal, Narottam P.
1994-01-01
Crystallization kinetics of BaO.Al2O3.2SiO2 (BAS) and SrO.Al2O3.2SiO2 (SAS) glasses in bulk and powder forms have been studied by non-isothermal differential scanning calorimetry (DSC). The crystal growth activation energies were evaluated to be 473 and 451 kJ/mol for bulk samples and 560 and 534 kJ/mol for powder specimens in BAS and SAS glasses, respectively. Development of crystalline phases on thermal treatments of glasses at various temperatures has been followed by powder x-ray diffraction. Powder samples crystallized at lower temperatures than the bulk and the crystallization temperature was lower for SAS glass than BAS. Crystallization in both glasses appeared to be surface nucleated. The high temperature phase hexacelsian, MAl2Si2O8 (M = Ba or Sr), crystallized first by nucleating preferentially on the glass surface. Also, monoclinic celsian does not nucleate directly in the glass, but is formed at higher temperatures from the transformation of the metastable hexagonal phase. In SAS the transformation to monoclinic celsian occurred rapidly after 1 h at 1100 C. In contrast, in BAS this transformation is sluggish and difficult and did not go to completion even after 10 h heat treatment at 1400 C. The crystal growth morphologies in the glasses have been observed by optical microscopy. Some of the physical properties of the two glasses are also reported.
Santala, M. K.; Raoux, S.; Campbell, G. H.
2015-12-24
The kinetics of laser-induced, liquid-mediated crystallization of amorphous Ge thin films were studied using multi-frame dynamic transmission electron microscopy (DTEM), a nanosecond-scale photo-emission transmission electron microscopy technique. In these experiments, high temperature gradients are established in thin amorphous Ge films with a 12-ns laser pulse with a Gaussian spatial profile. The hottest region at the center of the laser spot crystallizes in ~100 ns and becomes nano-crystalline. Over the next several hundred nanoseconds crystallization continues radially outward from the nano-crystalline region forming elongated grains, some many microns long. The growth rate during the formation of these radial grains is measuredmore » with time-resolved imaging experiments. Crystal growth rates exceed 10 m/s, which are consistent with crystallization mediated by a very thin, undercooled transient liquid layer, rather than a purely solid-state transformation mechanism. The kinetics of this growth mode have been studied in detail under steady-state conditions, but here we provide a detailed study of liquid-mediated growth in high temperature gradients. Unexpectedly, the propagation rate of the crystallization front was observed to remain constant during this growth mode even when passing through large local temperature gradients, in stark contrast to other similar studies that suggested the growth rate changed dramatically. As a result, the high throughput of multi-frame DTEM provides gives a more complete picture of the role of temperature and temperature gradient on laser crystallization than previous DTEM experiments.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Santala, M. K., E-mail: melissa.santala@oregonstate.edu; Campbell, G. H.; Raoux, S.
2015-12-21
The kinetics of laser-induced, liquid-mediated crystallization of amorphous Ge thin films were studied using multi-frame dynamic transmission electron microscopy (DTEM), a nanosecond-scale photo-emission transmission electron microscopy technique. In these experiments, high temperature gradients are established in thin amorphous Ge films with a 12-ns laser pulse with a Gaussian spatial profile. The hottest region at the center of the laser spot crystallizes in ∼100 ns and becomes nano-crystalline. Over the next several hundred nanoseconds crystallization continues radially outward from the nano-crystalline region forming elongated grains, some many microns long. The growth rate during the formation of these radial grains is measured withmore » time-resolved imaging experiments. Crystal growth rates exceed 10 m/s, which are consistent with crystallization mediated by a very thin, undercooled transient liquid layer, rather than a purely solid-state transformation mechanism. The kinetics of this growth mode have been studied in detail under steady-state conditions, but here we provide a detailed study of liquid-mediated growth in high temperature gradients. Unexpectedly, the propagation rate of the crystallization front was observed to remain constant during this growth mode even when passing through large local temperature gradients, in stark contrast to other similar studies that suggested the growth rate changed dramatically. The high throughput of multi-frame DTEM provides gives a more complete picture of the role of temperature and temperature gradient on laser crystallization than previous DTEM experiments.« less
Polymer Stabilization of Liquid-Crystal Blue Phase II toward Photonic Crystals.
Jo, Seong-Yong; Jeon, Sung-Wook; Kim, Byeong-Cheon; Bae, Jae-Hyun; Araoka, Fumito; Choi, Suk-Won
2017-03-15
The temperature ranges where a pure simple-cubic blue phase (BPII) emerges are quite narrow compared to the body-centered-cubic BP (BPI) such that the polymer stabilization of BPII is much more difficult. Hence, a polymer-stabilized BPII possessing a wide temperature range has been scarcely reported. Here, we fabricate a polymer-stabilized BPII over a temperature range of 50 °C including room temperature. The fabricated polymer-stabilized BPII is confirmed via polarized optical microscopy, Bragg reflection, and Kossel diagram observations. Furthermore, we demonstrate reflective BP liquid-crystal devices utilizing the reflectance-voltage performance as a potential application of the polymer-stabilized BPII. Our work demonstrates the possibility of practical application of the polymer-stabilized BPII to photonic crystals.
Miyanishi, Hideo; Nemoto, Takayuki; Mizuno, Masayasu; Mimura, Hisashi; Kitamura, Satoshi; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru
2013-02-01
To investigate crystallization behavior on the surface of amorphous solid dispersion powder using inverse gas chromatography (IGC) and to predict the physical stability at temperatures below the glass transition temperature (T (g)). Amorphous solid dispersion powder was prepared by melt-quenching of a mixture of crystalline nifedipine and polyvinylpyrrolidon (PVP) K-30. IGC was conducted by injecting undecane (probe gas) and methane (reference gas) repeatedly to the solid dispersion at temperatures below T (g). Surface crystallization was evaluated by the retention volume change of undecane based on the observation that the surface of the solid dispersion with crystallized nifedipine gives an increased retention volume. On applying the retention volume change to the Hancock-Sharp equation, surface crystallization was found to follow a two-dimensional growth of nuclei mechanism. Estimation of the crystallization rates at temperatures far below T (g) using the Avrami-Erofeev equation and Arrhenius equation showed that, to maintain its quality for at least three years, the solid dispersion should be stored at -20°C (T (g) - 65°C). IGC can be used to evaluate crystallization behavior on the surface of a solid dispersion powder, and, unlike traditional techniques, can also predict the stability of the solid dispersion based on the surface crystallization behavior.
Influence of Surrounding Dielectrics on the Data Retention Time of Doped Sb2Te Phase Change Material
NASA Astrophysics Data System (ADS)
Jedema, Friso; in `t Zandt, Micha; Wolters, Rob; Gravesteijn, Dirk
2011-02-01
The crystallization properties of as-deposited and laser written amorphous marks of doped Sb2Te phase change material are found to be only dependent on the top dielectric layer. A ZnS:SiO2 top dielectric layer yields a higher crystallization temperature and a larger crystal growth activation energy as compared to a SiO2 top dielectric layer, leading to superior data retention times at ambient temperatures. The observed correlation between the larger crystallization temperatures and larger crystal growth activation energies indicates that the viscosity of the phase change material in the amorphous state is dependent on the interfacial energy between the phase change material and the top dielectric layer.
Local structure of Ge2Sb2Te5 during crystallization under pressure
NASA Astrophysics Data System (ADS)
Roscioni, O. M.; Branicio, P. S.; Kalikka, J.; Zhou, X.; Simpson, R. E.
2018-04-01
The role of stress on the crystallization process of the phase change data storage material, Ge2Sb2Te5, is studied. When thin Ge2Sb2Te5 films are capped with Si3N4, stress is generated in the Ge2Sb2Te5 layer which causes the crystallization temperature to increase. Si3N4 films of 25 nm thickness increase the crystallization temperature from 446 K to 464 K. We show that stress predominantly destabilizes voids and increases the number of Ge-Sb and homopolar bonds in the vicinity of Ge atoms, and this makes the crystallization less probable, thus resulting in the increase in the measured temperature.
Military Family Coping Project - Phase 2
2014-09-01
ORGANIZATION: Baylor University, Waco , TX 76798 REPORT DATE: September 2014 TYPE OF REPORT: Annual PREPARED FOR: U.S. Army Medical Research and...February 28). Baylor, Waco VA hospital studying veterans’ family stress. Waco , TX: Tribune Herald. Slayden, Stacey (Reporter). (2012, February 28...VA Hospital and Baylor University team up to study effects of deployment. Waco , TX: Fox 44 news. Ellor, J. W., Crow, J, Myers, D., Morissette, S
Federal Register 2010, 2011, 2012, 2013, 2014
2013-03-06
... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [S-2-2013] Foreign-Trade Zone 196--Fort Worth, TX, Foreign-Trade Subzone 196A--TTI, Inc., Approval of Additional Subzone Site, Fort Worth, TX On January 4, 2013, the Executive Secretary of the Foreign-Trade Zones (FTZ) Board docketed an application submitted by Alliance Corridor, Inc., grantee of...
Thromboxane A2 moderates permeability after limb ischemia.
Lelcuk, S; Alexander, F; Valeri, C R; Shepro, D; Hechtman, H B
1985-01-01
Reperfusion after limb ischemia results in muscle edema as well as excess secretion of thromboxane A2 (TxA2), an agent associated with permeability increase in other settings. This study tests whether TxA2 moderates the permeability following limb ischemia. A tourniquet inflated to 300 mmHg was applied for 2 hours around the hind limb of four groups of dogs. In untreated animals (N = 25), 2 hours following tourniquet release, plasma TxB2 values rose from 320 pg/ml to 2416 pg/ml (p less than 0.001), and popliteal lymph values rose from 378 pg/ml to 1046 pg/ml (p less than 0.001). Platelet TxB2 was unaltered and plasma 6-keto-PGF1 alpha levels did not vary. Following ischemia, lymph flow (QL) increased from 0.07 to 0.37 ml/h (p less than 0.05), while the lymph/plasma (L/P) protein ratio was unchanged at 0.41. These measurements indicate increased permeability since increase in hydrostatic pressure in a second group by tourniquet inflation to 50 mmHg (N = 7) led to a rise in QL from 0.07 to 0.22 ml/h, but a fall in the L/P ratio to 0.32, a value lower than the ischemic group (p less than 0.05). Pretreatment with the imidazole derivative ketoconazole (N = 11) reduced platelet Tx synthesis from 42 ng to 2 ng/10(9) platelets, but lymph TxB2 levels rose to 1703 pg/ml after ischemia, indicating an extravascular or vessel wall site of synthesis not inhibited by ketoconazole. Pretreatment with a lower molecular weight imidazole derivative OKY 046 (N = 9) inhibited all Tx synthesis after ischemia. Prior to tourniquet inflation, both OKY 046 and ketoconazole lowered plasma TxB2 levels as well as the L/P ratio (p less than 0.05). After ischemia, OKY 046, but not ketoconazole, maintained the L/P ratio at 0.33, a value below that of untreated animals (p less than 0.05). These results indicate that nonplatelet-derived TxA2 modulates both baseline and ischemia-induced increases in microvascular permeability in the dog hind limb. PMID:3840349
Xiao, Yucheng; Blumenthal, Kenneth; Jackson, James O; Liang, Songping; Cummins, Theodore R
2010-12-01
The voltage-gated sodium channel Na(v)1.7 plays a crucial role in pain, and drugs that inhibit hNa(v)1.7 may have tremendous therapeutic potential. ProTx-II and huwentoxin-IV (HWTX-IV), cystine knot peptides from tarantula venoms, preferentially block hNa(v)1.7. Understanding the interactions of these toxins with sodium channels could aid the development of novel pain therapeutics. Whereas both ProTx-II and HWTX-IV have been proposed to preferentially block hNa(v)1.7 activation by trapping the domain II voltage-sensor in the resting configuration, we show that specific residues in the voltage-sensor paddle of domain II play substantially different roles in determining the affinities of these toxins to hNa(v)1.7. The mutation E818C increases ProTx-II's and HWTX-IV's IC(50) for block of hNa(v)1.7 currents by 4- and 400-fold, respectively. In contrast, the mutation F813G decreases ProTx-II affinity by 9-fold but has no effect on HWTX-IV affinity. It is noteworthy that we also show that ProTx-II, but not HWTX-IV, preferentially interacts with hNa(v)1.7 to impede fast inactivation by trapping the domain IV voltage-sensor in the resting configuration. Mutations E1589Q and T1590K in domain IV each decreased ProTx-II's IC(50) for impairment of fast inactivation by ~6-fold. In contrast mutations D1586A and F1592A in domain-IV increased ProTx-II's IC(50) for impairment of fast inactivation by ~4-fold. Our results show that whereas ProTx-II and HWTX-IV binding determinants on domain-II may overlap, domain II plays a much more crucial role for HWTX-IV, and contrary to what has been proposed to be a guiding principle of sodium channel pharmacology, molecules do not have to exclusively target the domain IV voltage-sensor to influence sodium channel inactivation.
Plant, T. M.; Ramaswamy, S.; Bhat, G. K.; Stah, C. D.; Pohl, C. R.; Mann, D. R.
2010-01-01
The present study examined whether a transient thyroid hormone (T4) deficit during infancy in male monkeys would compromise the arrest of luteinising hormone (LH) secretion during the infant–juvenile transition, and/or interfere with the pubertal resurgence of LH. Animals were orchidectomised and thyroidectomised (n = 3; Tx) or sham Tx (n = 3) within 5 days of birth. T4 replacement was initiated in two Tx monkeys at age 19 weeks to reestablish a euthyroid condition. Blood samples were drawn weekly for hormone assay. Body weight, crown–rump length, and bone age were assessed throughout the study. Within a week of Tx, plasma T4 declined to undetectable levels and, by 6–8 weeks of age, signs of hypothyroidism were evident. Transient hypothyroidism during infancy failed to prevent either arrest of LH secretion during the infant–juvenile transition or the pubertal resurgence of LH secretion, both of which occurred at similar ages to sham Tx animals. Although body weight exhibited complete catch-up with T4 replacement, crown–rump length and bone age did not. Thus, bone age at the time of the pubertal LH resurgence in Tx animals was less advanced than that in shams. Although Tx did not influence qualitatively the pattern of gonadotrophin secretion, LH levels during infancy and after pubertal LH resurgence were elevated in Tx monkeys. This was not associated with changes in LH pulse frequency and amplitude, but half-life (53 versus 65 min) of the slow second phase of LH clearance was greater in Tx animals. These results indicate that hypothalamic mechanisms dictating the pattern of gonadotrophin-releasing hormone release from birth to puberty are not dependent on T4 action during infancy, and fail to support the notion that onset of puberty is causally coupled to skeletal maturation. They also indicate that LH renal clearance mechanisms may be programmed in a T4 dependent manner during infancy. PMID:18673410
NASA Astrophysics Data System (ADS)
Zahari, Zakirah Mohd; Zubaidah Adnan, Siti; Kanthasamy, Ramesh; Saleh, Suriyati; Samad, Noor Asma Fazli Abdul
2018-03-01
The specification of the crystal product is usually given in terms of crystal size distribution (CSD). To this end, optimal cooling strategy is necessary to achieve the CSD. The direct design control involving analytical CSD estimator is one of the approaches that can be used to generate the set-point. However, the effects of temperature on the crystal growth rate are neglected in the estimator. Thus, the temperature dependence on the crystal growth rate needs to be considered in order to provide an accurate set-point. The objective of this work is to extend the analytical CSD estimator where Arrhenius expression is employed to cover the effects of temperature on the growth rate. The application of this work is demonstrated through a potassium sulphate crystallisation process. Based on specified target CSD, the extended estimator is capable of generating the required set-point where a proposed controller successfully maintained the operation at the set-point to achieve the target CSD. Comparison with other cooling strategies shows a reduction up to 18.2% of the total number of undesirable crystals generated from secondary nucleation using linear cooling strategy is achieved.
Defect chemistry and characterization of (Hg, Cd)Te
NASA Technical Reports Server (NTRS)
Vydyanath, H. R.
1981-01-01
Single crystal samples of phosphorus doped Hg sub 0.8 Cd sub 0.2 Te were anneald at temperatures varying from 450 C to 600 C in various Hg atmospheres. The samples were quenched to room temperature from the annealing temperatures. Hall effect and mobility measurements were performed at 77 K on all these samples. The results indicate the crystals to be p type for a total phosphorus concentration of 10 to the 19th power/cu cm in all the samples. The hole concentration at 77 K increases with increasing Hg pressures at 450 C and 500 C contrary to the observation in undoped crystals. Also, at low Hg pressures the concentration of holes in the phosphorus doped crystals is lower than in the undoped crystals. The hole concentration in all the samples is lower than the intrinsic carrier concentration at the annealing temperatures. The hole mobility in the doped crystals is similar to that in the undoped crystals. A defect model according to which phosphorus behaves as a single acceptor interstitially, occupying Te lattice sites while it acts as a single donor occupying Hg lattice sites was established. Equilibrum constants established for the incorporation of all the phosphorus species explain the experimental results
Growth, Crystal Structure and Magnetic Characterization of Zn-Stabilized CePtIn4
NASA Astrophysics Data System (ADS)
Carnicom, Elizabeth M.; Klimczuk, Tomasz; von Rohr, Fabian; Winiarski, Michal J.; Kong, Tai; Stolze, Karoline; Xie, Weiwei; Kushwaha, Satya K.; Cava, Robert J.
2017-08-01
The growth and characterization of CePtIn4, stabilized by 10% Zn substitution for In, is reported. The new material is orthorhombic, space group Cmcm (No. 63), with lattice parameters a = 4.51751(4) Å, b = 16.7570(2) Å, and c = 7.36682(8) Å, and the refined crystal composition has 10% of Zn substituted for In, i.e., the crystals are CePt(In0.9Zn0.1)4. Crystals were grown using a self-flux method: only growths containing Zn yielded CePtIn4 crystals, while Ce3Pt4In13 crystals formed when Zn was not present. Anisotropic temperature-dependent magnetic susceptibilities for single crystals show that Zn-stabilized CePtIn4 orders magnetically at ˜1.9 K. High-temperature Curie-Weiss fits indicate an effective moment of ˜2.49 μB/Ce and a directionally averaged Weiss-temperature of approximately -31 K. Specific heat data shows a peak consistent with the ordering temperature seen in the magnetic susceptibility data. Zn-stabilized CePtIn4 is metallic and displays no superconducting transition down to 0.14 K.
On melt solutions for the growth of CaTiO3 crystals
NASA Astrophysics Data System (ADS)
Klimm, Detlef; Schmidt, Max; Wolff, Nora; Guguschev, Christo; Ganschow, Steffen
2018-03-01
When calcium titanate crystals are grown from stoichiometric melts, they crystallize in the cubic perovskite structure. Upon cooling to room temperature they undergo subsequent phase transitions to tetragonal and orthorhombic modifications. These phase transitions are disruptive and result in severely damaged crystals. This paper presents differential thermal analysis data for several prospective solvents, with the aim to identify a system offering the possibility to perform crystal growth of undistorted CaTiO3 crystals by crystallizing them significantly below the melting point directly in the low temperature modification. From mixtures CaF2:TiO2:CaTiO3 = 3:1:1 (molar ratio) the growth of undistorted, at least millimeter-sized CaTiO3 crystals is possible.
NASA Astrophysics Data System (ADS)
Furukawa, Kazuki; Yamamoto, Norifumi; Hino, Kazuyuki; Sekiya, Hiroshi
2016-01-01
The effect of intermolecular interaction on excited-state intramolecular proton transfer (ESIPT) in 4‧-N,N-dimethylamino-3-hydroxyflavone (DMHF) doped in acetonitrile crystals was investigated by measuring the temperature dependence of fluorescence excitation and fluorescence spectra. A solid/solid phase transition of DMHF-doped acetonitrile crystals occurred in the temperature between 210 and 218 K. Significant differences in the spectral profiles and shifts in the fluorescence spectra were observed in the low- and high-temperature regions of the phase transition. The temperature dependence of the ESIPT potential of DMHF is discussed.
DOE Office of Scientific and Technical Information (OSTI.GOV)
NONE
1996-03-01
This decision document presents the selected Early Interim Remedial Action for the Burning Ground No. 3 site (the site), Longhorn Army Ammunition Plant, in Karnack, Texas. The major components of the selected remedy include: extraction and Treatment of contaminated shallow groundwater using Organic Air Stripping and Off-gas Treatment and Metals precipitation, and Excavation and Treatment of Source Material using Low Temperature Thermal Desorption and Catalytic Oxidation for off-gas.
General view of the aft section of the Orbiter Discovery ...
General view of the aft section of the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. Note the main engines and Orbiter Maneuvering System/Reaction Control System pods are removed in this photo. The flexible hoses protruding from the starboard aft section are to control temperature, humidity and pressure in the orbiter's void spaces during its down time. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX
General view of the aft, starboard section of the Orbiter ...
General view of the aft, starboard section of the Orbiter Discovery in the Vehicle Assembly Building at NASA's Kennedy Space Center. Note the main engines and Orbiter Maneuvering System/Reaction Control System pods are removed in this photo. The flexible hoses protruding from the starboard aft section are to control temperature, humidity and pressure in the orbiter's void spaces during its down time. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX
1989-12-15
epidermal surfaces were exposed to ambient air (220C) during the entire length of the experiment. Penetration of [3H]PbTx-3 into skin layers and receptor...bathed by the receptor fluid and the epidermal surface was exposed to ambient conditions in an en- vironmental chamber. Temperature and relative...DMSO or water. The epidermal surfaces were exposed to ambient conditions in the environmental chamber. In order to determine if constituents leaching
Vanhoof, Jasper M M; Vandenberghe, Bert; Geerts, David; Philippaerts, Pieter; De Mazière, Patrick; DeVito Dabbs, Annette; De Geest, Sabina; Dobbels, Fabienne
2018-03-01
The use of interactive health technology (IHT) is a promising pathway to tackle self-management problems experienced by many chronically ill patients, including solid organ transplant (Tx) patients. Yet, to ensure that the IHT is accepted and used, a human-centered design process is needed, actively involving end users in all steps of the development process. A first critical, predevelopment step involves understanding end users' characteristics. This study therefore aims to (a) select an IHT platform to deliver a self-management support intervention most closely related to Tx patients' current use of information and communication technologies (ICTs), (b) understand Tx patients' overall willingness to use IHT for self-management support, and investigate associations with relevant technology acceptance variables, and (c) explore Tx patients' views on potential IHT features. We performed a cross-sectional, descriptive study between October and December 2013, enrolling a convenience sample of adult heart, lung, liver, and kidney Tx patients from the University Hospitals Leuven, Belgium. Broad inclusion criteria were applied to ensure a representative patient sample. We used a 35-item newly designed interview questionnaire to measure Tx patients' use of ICTs, their overall willingness to use IHT, and their views on potential IHT features, as well as relevant technology acceptance variables derived from the Unified Theory of Acceptance and Use of Technology and a literature review. Descriptive statistics were used as appropriate, and an ordinal logistic regression model was built to determine the association between Tx patients' overall willingness to use IHT, the selected technology acceptance variables, and patient characteristics. Out of 139 patients, 122 agreed to participate (32 heart, 30 lung, 30 liver, and 30 kidney Tx patients; participation rate: 88%). Most patients were male (57.4%), married or living together (68%), and had a mean age of 55.9 ± 13.4 years. Only 27.9% of Tx patients possessed a smartphone, yet 72.1% owned at least one desktop or laptop PC with wireless Internet at home. On a 10-point numeric scale, asking patients whether they think IHT development is important to support them personally in their self-management, patients gave a median score of 7 (25th percentile 5 points; 75th percentile 10 points). Patients who were single or married or living together were more likely to give a higher rating than divorced or widowed patients; patients who completed only secondary education gave a higher rating than higher educated patients; and patients with prior ICT use gave a higher rating than patients without prior ICT use. Tx patients also had clear preferences regarding IHT features, such as automatic data transfer, as much as possible, visual aids (e.g., graphs) over text messages, and personally deciding when to access the IHT. By investigating Tx patients' possession and use of ICTs, we learned that computers and the Internet, and not smartphones, are the most suitable IHT platforms to deliver self-management interventions for our Tx patients. Moreover, Tx patients generally are open to using IHT, yet patient acceptance variables and their preferences for certain IHT features should be taken into account in the next steps of IHT development. Designers intending to develop or use existing IHTs should never overlook this critical first step in a human-centered design. Before considering using eHealth technology in clinical practice, professionals should always check whether patients are familiar with using information and communication technology, and whether they are willing to use technology for health-related purposes. © 2017 Sigma Theta Tau International.
The Effect of Acidity Coefficient on Crystallization Behavior of Blast Furnace Slag Fibers
NASA Astrophysics Data System (ADS)
Tian, Tie-Lei; Zhang, Yu-Zhu; Xing, Hong-wei; Li, Jie; Zhang, Zun-Qian
2018-01-01
The chemical structure of mineral wool fiber was investigated by using Fourier Transform Infrared Spectroscopy (FTIR). Next, the glass transition temperature and the crystallization temperature of the fibers were studied. Finally, the crystallization kinetics of fiber was studied. The results show that the chemical bond structure of fibers gets more random with the increase of acidity coefficient. The crystallization phases of the fibers are mainly melilites, and also a few anorthites and diopsides. The growth mechanism of the crystals is three dimensional. The fibers with acidity coefficient of 1.2 exhibit the best thermal stability and is hard to crystallize as it has the maximum aviation energy of crystallization kinetics.
Chemical Contamination of the Lower Rio Grande near Laredo, TX
NASA Astrophysics Data System (ADS)
Flores, B.; Ren, J.; Krishnamurthy, S.; Belzer, W.
2006-12-01
The Rio Grande River stretches over 2000 miles from the southern Rocky Mountains in Colorado to the tip of Texas where the Rio Grande meets the Gulf of Mexico. It is the natural boundary between U.S. and Mexico from El Paso, TX, to Brownsville, TX. The communities along the border heavily rely upon the Rio Grande as a primary source of water for consumption, agricultural uses, supporting wildlife and recreation. For many years the Rio Grande has been polluted with municipal, industrial, agricultural and farming contaminants from both sides of the border. This pollution has led to the extinction or reduction of certain wildlife species as well as affecting the health of the residences along the border. Even though great strides have been made in monitoring the Rio Grande, there has been a lack of intense monitoring data collection for pollutants such as pesticides. Three sampling sites including Manadas Creek, the Rio Grande River at International Bridge I, and USGS monitoring site 08459200 off of Highway 83 were chosen. The water quality parameters focused include temperature, pH, conductivity, dissolve oxygen (DO), salinity, total dissolved solids, nutrients, metals and pesticides. Preliminary results have shown elevated concentration of total phosphorus and ortho-phosphorus in the Manadas Creek site. Organochlorinated pesticides such as heptachlor and 4, 4 DDE were detected at various concentrations at all sites and endrin aldehyde was found at Manadas Creek site. This research has provided more information on the current chemical contamination level of the Rio Grande in the Laredo area.
How fragility makes phase-change data storage robust: insights from ab initio simulations
Zhang, Wei; Ronneberger, Ider; Zalden, Peter; Xu, Ming; Salinga, Martin; Wuttig, Matthias; Mazzarello, Riccardo
2014-01-01
Phase-change materials are technologically important due to their manifold applications in data storage. Here we report on ab initio molecular dynamics simulations of crystallization of the phase change material Ag4In3Sb67Te26 (AIST). We show that, at high temperature, the observed crystal growth mechanisms and crystallization speed are in good agreement with experimental data. We provide an in-depth understanding of the crystallization mechanisms at the atomic level. At temperatures below 550 K, the computed growth velocities are much higher than those obtained from time-resolved reflectivity measurements, due to large deviations in the diffusion coefficients. As a consequence of the high fragility of AIST, experimental diffusivities display a dramatic increase in activation energies and prefactors at temperatures below 550 K. This property is essential to ensure fast crystallization at high temperature and a stable amorphous state at low temperature. On the other hand, no such change in the temperature dependence of the diffusivity is observed in our simulations, down to 450 K. We also attribute this different behavior to the fragility of the system, in combination with the very fast quenching times employed in the simulations. PMID:25284316
Controllable Growth of Monolayer MoS2 and MoSe2 Crystals Using Three-temperature-zone Furnace
NASA Astrophysics Data System (ADS)
Zheng, Binjie; Chen, Yuanfu
2017-12-01
Monolayer molybdenum disulfide (MoS2) and molybdenum diselenide (MoSe2) have attracted a great attention for their exceptional electronic and optoelectronic properties among the two dimensional family. However, controllable synthesis of monolayer crystals with high quality needs to be improved urgently. Here we demonstrate a chemical vapor deposition (CVD) growth of monolayer MoS2 and MoSe2 crystals using three-temperature-zone furnace. Systematical study of the effects of growth pressure, temperature and time on the thickness, morphology and grain size of crystals shows the good controllability. The photoluminescence (PL) characterizations indicate that the as-grown monolayer MoS2 and MoSe2 crystals possess excellent optical qualities with very small full-width-half-maximum (FWHM) of 96 me V and 57 me V, respectively. It is comparable to that of exfoliated monolayers and reveals their high crystal quality. It is promising that our strategy should be applicable for the growth of other transition metal dichalcogenides (TMDs) monolayer crystals.
Solid state crystal physics at very low temperatures
NASA Technical Reports Server (NTRS)
Davis, W.; Krack, K.; Richard, J. P.; Weber, J.
1980-01-01
The properties of nearly perfect crystals was studied at cryogenic temperatures. A large Helium 3 and Helium 4 dilution refrigerator has been assembled, and is described. A cryostat suitable for cooling a 35 liter volume to .020 Kelvin was designed and constructed, together with instrumentation to observe the properties of nearly perfect crystals.
Brevetoxin exposure in sea turtles in south Texas (USA) during Karenia brevis red tide.
Walker, Jennifer Shelby; Shaver, Donna J; Stacy, Brian A; Flewelling, Leanne J; Broadwater, Margaret H; Wang, Zhihong
2018-01-31
Five green (Chelonia mydas) and 11 Kemp's ridley (Lepidochelys kempii) sea turtles found dead, or that died soon after stranding, on the southern Texas (USA) coast during 2 Karenia brevis blooms (October 2015, September-October 2016) were tested for exposure to brevetoxins (PbTx). Tissues (liver, kidney) and digesta (stomach and intestinal contents) were analyzed by ELISA. Three green turtles found alive during the 2015 event and 2 Kemp's ridley turtles found alive during the 2016 event exhibited signs of PbTx exposure, including lethargy and/or convulsions of the head and neck. PbTx were detected in 1 or more tissues or digesta in all 16 stranded turtles. Detected PbTx concentrations ranged from 2 to >2000 ng g-1. Necropsy examination and results of PbTx analysis indicated that 10 of the Kemp's ridleys and 2 of the green turtles died from brevetoxicosis via ingestion. This is the first documentation of sea turtle mortality in Texas attributed to brevetoxicosis.
Bea, Ana M; Perez-Calahorra, Sofia; Marco-Benedi, Victoria; Lamiquiz-Moneo, Itziar; Jarauta, Estibaliz; Mateo-Gallego, Rocio; Civeira, Fernando
2017-08-01
The effect of LDLc lowering with PCSK9 antibodies on tendon xanthomas (TX) is unknown. TX was measured in 24 heterozygous familial hypercholesterolemia (HeFH) cases and in 24 HeFH controls with or without PCSK9 inhibitors for at least one year. Exposure to PCSK9 inhibitors in cases was 2.96 ± 1.33 years. LDLc decreased 80.8 ± 7.66% in cases and 56.9 ± 11.1% in controls. There was a decrease in maximum (-5.03%) and mean (-5.32%) TX in cases but not in controls (+3.97%, +3.16, respectively, p = 0.01). PCSK9 inhibitor treatment was independently associated with TX reduction. Addition of a PCSK9 inhibitor to statin and ezetimibe resulted in a greater decrease in LDLc and TX after 3 years of treatment. Copyright © 2017 Elsevier B.V. All rights reserved.
Yu, Fapeng; Zhang, Shujun; Zhao, Xian; Yuan, Duorong; Qin, Lifeng; Wang, Qing-Ming; Shrout, Thomas R
2011-04-01
The electrical resistivity, dielectric, and electromechanical properties of ReCa(4)O(BO(3))(3) (ReCOB; Re = Er, Y, Gd, Sm, Nd, Pr, and La) piezoelectric crystals were investigated as a function of temperature up to 1000 °C. Of the studied crystals, ErCOB and YCOB were found to possess extremely high resistivity (p): p > 3 × 10(7) ω.cm at 1000 °C. The property variation in ReCOB crystals is discussed with respect to their disordered structure. The highest electromechanical coupling factor κ(26) and piezoelectric coefficient d(26) at 1000°C, were achieved in PrCOB crystals, with values being on the order of 24.7% and 13.1 pC/N, respectively. The high thermal stability of the electromechanical properties, with variation less than 25%, together with the low dielectric loss (<46%) and high mechanical quality factor (>1500) at elevated temperatures of 1000 °C, make ErCOB, YCOB, and GdCOB crystals promising for ultrahigh temperature electromechanical applications. © 2011 IEEE
Inorganic pyrophosphatase crystals from Thermococcus thioreducens for X-ray and neutron diffraction.
Hughes, Ronny C; Coates, Leighton; Blakeley, Matthew P; Tomanicek, Steve J; Langan, Paul; Kovalevsky, Andrey Y; García-Ruiz, Juan M; Ng, Joseph D
2012-12-01
Inorganic pyrophosphatase (IPPase) from the archaeon Thermococcus thioreducens was cloned, overexpressed in Escherichia coli, purified and crystallized in restricted geometry, resulting in large crystal volumes exceeding 5 mm3. IPPase is thermally stable and is able to resist denaturation at temperatures above 348 K. Owing to the high temperature tolerance of the enzyme, the protein was amenable to room-temperature manipulation at the level of protein preparation, crystallization and X-ray and neutron diffraction analyses. A complete synchrotron X-ray diffraction data set to 1.85 Å resolution was collected at room temperature from a single crystal of IPPase (monoclinic space group C2, unit-cell parameters a=106.11, b=95.46, c=113.68 Å, α=γ=90.0, β=98.12°). As large-volume crystals of IPPase can be obtained, preliminary neutron diffraction tests were undertaken. Consequently, Laue diffraction images were obtained, with reflections observed to 2.1 Å resolution with I/σ(I) greater than 2.5. The preliminary crystallographic results reported here set in place future structure-function and mechanism studies of IPPase.
Smith, G.I.; Friedman, I.; McLaughlin, R.J.
1987-01-01
As a consequence of the 1969-1970 flooding of normally dry Owens Lake, a 2.4-m-deep lake formed and 20% of the 2-m-thick salt bed dissolved in it. Its desiccation began August 1969, and salts started crystallizing September 1970, ending August 1971. Mineralogic, brine-composition, and stable-isotope data plus field observations showed that while the evolving brine composition established the general crystallization timetable and range of primary and secondary mineral assemblages, it was the daily, monthly, and seasonal temperature changes that controlled the details of timing and mineralogy during this depositional process. Deuterium analyses of lake brine, interstitial brine, and hydrated saline phases helped confirm the sequence of mineral crystallizations and transformations, and they documented the sources and temperatures of waters involved in the reactions. Salts first crystallized as floating rafts on the lake surface. Natron and mirabilite, salts whose solubilities decrease greatly with lowering temperatures, crystallized late at night in winter, when surface-water temperatures reached their minima; trona, nahcolite, burkeite, and halite, salts with solubilities less sensitive to temperature, crystallized during the afternoon in summer, when surface salinities reached their maxima. However, different temperatures were generally associated with crystallization (at the surface) and accumulation (on the lake floor) because short-term temperature changes were transmitted to surface and bottom waters at different rates. Consequently, even when solubilities were exceeded at the surface, salts were preserved or not as a function of bottom-water temperatures. Halite, a nearly temperature-insensitive salt, was always preserved. Monitoring the lake-brine chemistry and mineralogy of the accumulating salts shows: (1) An estimated 0.9 ?? 106 tons of CO2 was released to the atmosphere or consumed by the lake's biomass prior to most salt crystallization. (2) After deposition, some salts reacted in situ to form other minerals in less than one month, and all salts (except halite) decomposed or recrystallized at least once in response to seasons. (3) Warming in early 1971 caused solution of all the mirabilite and some of the natron deposited a few months earlier, a deepening of the lake (though the lake-surface lowered), and an increase in dissolved solids. (4) Phase and solubility-index data suggest that at the close of desiccation, Na2CO3??7H2O, never reported as a mineral, could have been the next phase to crystallize. ?? 1987.
NASA Astrophysics Data System (ADS)
Caliskan, Betul; Caliskan, Ali Cengiz
2017-06-01
Bis(cyclopentadienyl)zirconium dichloride (BCZD; zirconocene dichloride) single crystals were exposed to 60Co-γ irradiation at room temperature. The irradiated single crystals were investigated between 125 and 470 K by electron paramagnetic resonance spectroscopy. The spectra of the crystals were found to be temperature independent. The paramagnetic center was attributed to the cyclopentadienyl radical. The g values of the radiation damage center observed in BCZD single crystal and the hyperfine structure constants of the free electron with nearby protons were obtained.
Edwards, A D; Shekunov, B Y; Kordikowski, A; Forbes, R T; York, P
2001-08-01
Pure anhydrous polymorphs of carbamazepine were prepared by solution-enhanced dispersion with supercritical fluids (SEDS). Crystallization of the polymorphs was studied. Mechanisms are proposed that consider the thermodynamics of carbamazepine, supersaturation in the SEDS process, and the binary phase equilibria of organic solvents and the carbon dioxide antisolvent. alpha-Carbamazepine was crystallized at high supersaturations and low temperatures, beta-carbamazepine crystallized from a methanol-carbon dioxide phase split, and gamma-carbamazepine crystallized via nucleation at high temperatures and low supersaturation. Copyright 2001 Wiley-Liss, Inc.
NASA Astrophysics Data System (ADS)
Chareev, D. A.; Volkova, O. S.; Geringer, N. V.; Koshelev, A. V.; Nekrasov, A. N.; Osadchii, V. O.; Osadchii, E. G.; Filimonova, O. N.
2016-07-01
Some examples of growing crystals of metals, alloys, chalcogenides, and pnictides in melts of halides of alkali metals and aluminum at a steady-state temperature gradient are described. Transport media are chosen to be salt melts of eutectic composition with the participation of LiCl, NaCl, KCl, RbCl, CsCl, AlCl3, AlBr3, KBr, and KI in a temperature range of 850-150°C. Some crystals have been synthesized only using a conducting contour. This technique of crystal growth is similar to the electrochemical method. In some cases, to exclude mutual influence, some elements have been isolated and forced to migrate to the crystal growth region through independent channels. As a result, crystals of desired quality have been obtained using no special equipment and with sizes sufficient for study under laboratory conditions.
Temperature tuning of lasing emission from dye-doped liquid crystal at intermediate twisted phase
NASA Astrophysics Data System (ADS)
Liao, Kuan-Cheng; Lin, Ja-Hon; Jian, Li-Hao; Chen, Yao-Hui; Wu, Jin-Jei
2015-07-01
Temperature tuning of lasing emission from dye-doped cholesteric liquid crystal (CLC) at intermediate twisted phase has been demonstrated in this work. With heavily doping of 42.5% chiral molecules into the nematic liquid crystals, the shifts of photonic bandgap versus temperature is obviously as thermal controlling of the sample below the certain value. By the differential scanning calorimetr measuremet, we demonstrate the phase transition from the CLC to the smectic phase when the temperature is lowered to be about 15°C. Between CLC and smectic phase, the liquid crystal mixtures are operated at intermediate twisted phase that can be used the temperature related refractive mirror. After pump by the Q-switched Nd:YAG laser, the lasing emission from this dye doped LC mixtures has been demonstrated whose emission wavelength can be tuned from 566 to 637 nm with 1.4°C variation.
Visualization of boundary-layer development on turbomachine blades with liquid crystals
NASA Technical Reports Server (NTRS)
Vanzante, Dale E.; Okiishi, Theodore H.
1991-01-01
This report documents a study of the use of liquid crystals to visualize boundary layer development on a turbomachine blade. A turbine blade model in a linear cascade of blades was used for the tests involved. Details of the boundary layer development on the suction surface of the turbine blade model were known from previous research. Temperature sensitive and shear sensitive liquid crystals were tried as visual agents. The temperature sensitive crystals were very effective in their ability to display the location of boundary layer flow separation and reattachment. Visualization of natural transition from laminar to turbulent boundary layer flow with the temperature sensitive crystals was possible but subtle. The visualization of separated flow reattachment with the shear sensitive crystals was easily accomplished when the crystals were allowed to make a transition from the focal-conic to a Grandjean texture. Visualization of flow reattachment based on the selective reflection properties of shear sensitive crystals was achieved only marginally because of the larger surface shear stress and shear stress gradient levels required for more dramatic color differences.
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Wage and Salary Stabilization in a National Security Emergency
1984-10-01
Arkansas Houston, Texas Eldorado, AR Bryan, TX Fayetteville, AR Lufkin, TX 2-8 Wage and Salary 2 - 9 . Region VI cont. Fort Smith, AR Waco, TX Jonesboro , AR ...applied to: financial and monetary systems: wages, salaries, and benefits; prices; rents; and rationing of essential goods. These measures are ...in terms of a number of conditions. They are : CONDITION I: Peacetime CONDITION II: National emergency (Threat of war) CONDITION ILIA: Mobilization
Proximity functions for electrons up to 10 keV
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chmelevsky, D.; Kellerer, A.M.; Terrissol, M.
1980-11-01
Proximity functions for electrons up to 10 keV in water are computed from simulated particle tracks. Numerical results are given for the differential functions t(x) and the integral functions T(x). Basic characteristics of these functions and their connections to other microdosimetric quantities are considered. As an example of the applicability of the proximity functions, the quantity y/sub D/ for spheres is derived from t(x).
Optical photometry of TX0506+056
NASA Astrophysics Data System (ADS)
Keel, William; Santander, Marcos
2017-10-01
The blazar TX0506+056 has attracted recent attention through its location in the error box of a high-energy Ice Cube neutrino detection (https://gcn.gsfc.nasa.gov/gcn3/21916.gcn3) and gamma-ray flaring (Atel #10791) We report recent photometry of TX0506+056 obtained in Johnson V and Cousins R passbands using the 1-meter Kapteyn telescope at La Palma, operated remotely by the SARA consortium.
DoD Security Assistance Management Manual
1988-10-01
IDSS Administrator for U.S. Army Training Activities: TSASS Database Manager SATFA Attn: ATFA-I 2017 Cunningham Drive, 4th Floor Hampton VA 23666 DSN...Depot, Chambersburg, PA J. School of Engineering and Logistics, Red River Army Depot, Texarkana , "TX K. Lone Star Ammunition Plant, Texarkana , TX L...Electronics Command, Ft. Monmouth, NJ U. Red River Army Depot, Texarkana , TX V. Army Aviation Research and Development Command, St. Louis, MO W
Dynamically-downscaled projections of changes in temperature extremes over China
NASA Astrophysics Data System (ADS)
Guo, Junhong; Huang, Guohe; Wang, Xiuquan; Li, Yongping; Lin, Qianguo
2018-02-01
In this study, likely changes in extreme temperatures (including 16 indices) over China in response to global warming throughout the twenty-first century are investigated through the PRECIS regional climate modeling system. The PRECIS experiment is conducted at a spatial resolution of 25 km and is driven by a perturbed-physics ensemble to reflect spatial variations and model uncertainties. Simulations of present climate (1961-1990) are compared with observations to validate the model performance in reproducing historical climate over China. Results indicate that the PRECIS demonstrates reasonable skills in reproducing the spatial patterns of observed extreme temperatures over the most regions of China, especially in the east. Nevertheless, the PRECIS shows a relatively poor performance in simulating the spatial patterns of extreme temperatures in the western mountainous regions, where its driving GCM exhibits more uncertainties due to lack of insufficient observations and results in more errors in climate downscaling. Future spatio-temporal changes of extreme temperature indices are then analyzed for three successive periods (i.e., 2020s, 2050s and 2080s). The projected changes in extreme temperatures by PRECIS are well consistent with the results of the major global climate models in both spatial and temporal patterns. Furthermore, the PRECIS demonstrates a distinct superiority in providing more detailed spatial information of extreme indices. In general, all extreme indices show similar changes in spatial pattern: large changes are projected in the north while small changes are projected in the south. In contrast, the temporal patterns for all indices vary differently over future periods: the warm indices, such as SU, TR, WSDI, TX90p, TN90p and GSL are likely to increase, while the cold indices, such as ID, FD, CSDI, TX10p and TN10p, are likely to decrease with time in response to global warming. Nevertheless, the magnitudes of changes in all indices tend to decrease gradually with time, indicating the projected warming will begin to slow down in the late of this century. In addition, the projected range of changes for all indices would become larger with time, suggesting more uncertainties would be involved in long-term climate projections.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Skalski, Michael; Coppolino, Marc G.
2005-10-07
In this study, the role of SNARE-mediated membrane traffic in regulating integrin localization was examined and the requirement for SNARE function in cellular spreading was quantitatively assessed. Membrane traffic was inhibited with the VAMP-specific catalytic light chain from tetanus toxin (TeTx-LC), a dominant-negative form (E329Q) of N-ethylmaleimide-sensitive fusion protein (NSF), and brefeldin A (BfA). Inhibition of membrane traffic with either E329Q-NSF or TeTx-LC, but not BfA, significantly inhibited spreading of CHO cells on fibronectin. Spreading was rescued in TeTx-LC-expressing cells by co-transfection with a TeTx-resistant cellubrevin/VAMP3. E329Q-NSF, a general inhibitor of SNARE function, was a more potent inhibitor of cellmore » spreading than TeTx-LC, suggesting that tetanus toxin-insensitive SNAREs contribute to adhesion. It was found that E329Q-NSF prevented trafficking of {alpha}{sub 5}{beta}{sub 1} integrins from a central Rab11-containing compartment to sites of protrusion during cell adhesion, while TeTx-LC delayed this trafficking. These results are consistent with a model of cellular adhesion that implicates SNARE function as an important component of integrin trafficking during the process of cell spreading.« less
Janicki, Krzysztof; Solski, Janusz; Janicka, Lucyna; Kimak, Elzbieta; Bednarek-Skublewska, Anna; Stettner, Seweryn; Molas, Grzegorz
2004-01-01
The aim of the study was to evaluate the serum lipid and apolipoprotein profiles among patients after renal transplantation (Tx) and to compare them with the profiles obtained for permanently hemodialysed patients (HD). The investigations were performed at 15 Tx, 40 HD patients and the control group of 40 healthy subjects. There were significantly increased TG, ApoAIII, ApoE, TC/ HDL-C, ApoCIII non B, ApoCIII:B and decreased HDL-C, ApoAI, HDL-C/ApoAI, ApoAI/ApoCIII, ApoB/ApoCIII ratios comparing HD patients to the control group. There were increased TG, ApoCIII, ApoCIII non B, ApoB/ApoCIII ratios and decreased ApoAI/ApoCIII ratios in Tx patients as compared to the control subjects. Moreover, there were significantly higher HDL, ApoAI, HDL/ApoAI, ApoCIII non B and lower ApoE, ApoE/ApoB, ApoCIII:B ratios in Tx patients as compared to these of HD patients. Significant inverse correlation of the time which passed from executed Tx and ApoCIII:B ratio (r = -0.67; p < 0.01) at renal transplant patients were observed, which means the diminished risk of development of atherosclerosis.
Tamta, Hemlata; Kalra, Sukirti; Thilagavathi, Ramasamy; Chakraborti, Asit K; Mukhopadhyay, Anup K
2007-02-01
Xanthine oxidase-catalyzed hydroxylation reactions of the anticancer drug 6-mercaptopurine (6-MP) and its analog 2-mercaptopurine (2-MP) as well as 6-thioxanthine (6-TX) and 2-thioxanthine (2-TX) have been studied using UV-spectroscopy, high pressure liquid chromatography, photodiode array, and liquid chromatography-based mass spectral analysis. It is shown that 6-MP and 2-MP are oxidatively hydroxylated through different pathways. Enzymatic hydroxylation of 6-MP forms 6-thiouric acid in two steps involving 6-TX as the intermediate, whereas 2-MP is converted to 8-hydroxy-2-mercaptopurine as the expected end product in one step. Surprisingly, in contrast to the other thiopurines, enzymatic hydroxylation of 2-MP showed a unique hyperchromic effect at 264 nm as the reaction proceeded. However, when 2-TX is used as the substrate, it is hydroxylated to 2-thiouric acid. The enzymatic hydroxylation of 2-MP is considerably faster than that of 6-MP, while 6-TX and 2-TX show similar rates under identical reaction conditions. The reason why 2-MP is a better substrate than 6-MP and how the chemical nature and position of the functional groups present on the thiopurine substrates influence xanthine oxidase activity are discussed.
Urban-air-toxics Monitoring Program carbonyl results, 1990
DOE Office of Scientific and Technical Information (OSTI.GOV)
Not Available
1991-07-01
The report summarizes the results of sampling ambient air for selected carbonyl containing compounds in 12 urban centers in the contiguous United States as part of the Urban Air Toxics Monitoring Program (UATMP). Formaldehyde, acetaldehyde, and acetone concentrations were measured using 2,4-dinitrophenylhydrazine (DNPH)-coated silica cartridges to collect the carbonyls for subsequent analysis. Sampling and analysis followed guidance provided in U.S. Environmental Protection Agency (EPA) compendium method TO-11. Formaldehyde concentrations ranged from 0.42 to 34.5 ppbv with an average concentration for all sites of 4.2 ppbv. Site average formaldehyde concentrations ranged from 1.5 ppbv for Houston, TX (H1TX) to 7.9 formore » Washington, DC (W2DC). Acetaldehyde concentrations ranged from 0.37 to 9.5 ppbv, averaging 1.7 ppbv over all 1990 UATMP sites. Site average acetaldehyde concentrations ranged from 0.76 ppbv at Houston, TX (H1TX) to 2.5 ppbv at Baton Rouge, LA (BRLA). Acetone concentrations ranged from 0.37 to 10.8 ppbv and averaged 1.8 ppbv over all sites. Site average acetone concentrations ranged from 0.68 ppbv at Houston, TX (H1TX) to 2.9 ppbv at Chicago, IL (C4IL).« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Feller, D.J.; Talvenheimo, J.A.; Catterall, W.A.
1985-09-25
Purified sodium channels incorporated into phosphatidylcholine (PC) vesicles mediate neurotoxin-activated SSNa influx but do not bind the alpha-scorpion toxin from Leiurus quinquestriatus (LqTx) with high affinity. Addition of phosphatidylethanolamine (PE) or phosphatidylserine to the reconstitution mixture restores high affinity LqTx binding with KD = 1.9 nM for PC/PE vesicles at -90 mV and 36 degrees C in sucrose-substituted medium. Other lipids tested were markedly less effective. The binding of LqTx in vesicles of PC/PE (65:35) is sensitive to both the membrane potential formed by sodium gradients across the reconstituted vesicle membrane and the cation concentration in the extravesicular medium. Bindingmore » of LqTx is reduced 3- to 4-fold upon depolarization to 0 mV from -50 to -60 mV in experiments in which (Na+)out/(Na+)in is varied by changing (Na+)in or (Na+)out at constant extravesicular ionic strength. It is concluded that the purified sodium channel contains the receptor site for LqTx in functional form and that restoration of high affinity, voltage-dependent binding of LqTx by the purified sodium channel requires an appropriate ratio of PC to PE and/or phosphatidylserine in the vesicle membrane.« less
Combined use of backscattered and transmitted images in x-ray personnel screening systems
NASA Astrophysics Data System (ADS)
Tracey, B.; Schiefele, Markus; Alvino, Christopher; Miller, Eric; Al-Kofani, Omar
2012-06-01
Current aviation security relies heavily on personnel screening using X-ray backscatter systems or other advanced imaging technologies. Passenger privacy concerns and screening times can be reduced through the use of low-dose twosided X-ray backscatter (Bx) systems, which also have the ability to collect transmission (Tx) X-ray. Bx images reveal objects placed on the body, such as contraband and security threats, as well as anatomical features at or close to the surface, such as lungs cavities and bones. While the quality of the transmission images is lower than medical imagery due to the low X-ray dose, Tx images can be of significant value in interpreting features in the Bx images, such as lung cavities, which can cause false alarms in automated threat detection (ATD) algorithms. Here we demonstrate an ATD processing chain fusing both Tx and BX images. The approach employs automatically extracted fiducial points on the body and localized active contour methods to segments lungs in acquired Tx and Bx images. Additionally, we derive metrics from the Tx image can be related to the probability of observing internal body structure in the Bx image. The combined use of Tx and Bx data can enable improved overall system performance.
Petit, L-M; Rabant, M; Canioni, D; Suberbielle-Boissel, C; Goulet, O; Chardot, C; Lacaille, F
2017-03-01
AMR is a risk factor for graft failure after SBTx. We studied impact of DSAs and AMR in 22 children transplanted between 2008 and 2012 (11 isolated SBTx, 10 liver inclusive Tx, and one modified multivisceral Tx). Three patients never developed DSA, but DSAs were found in seven in the pre-Tx period and de novo post-Tx in 19 children. Pathology revealed cellular rejection (15/19), with vascular changes and C4d+. Patients were treated with IV immunoglobulins, plasmapheresis, and steroids. Rescue therapy included antithymocyte globulins, rituximab, eculizumab, and bortezomib. Pathology and graft function normalized in 13 patients, graft loss occurred in two, and death in seven. At the end of the follow-up, 15 children were alive (68%), 13 with functioning graft (59%). Prognosis factors for poor outcome after Tx were the presence of symptoms at AMR suspicion (P +.033). DSAs were often found following SBTx, mostly de novo. Resistant ACR or severe AMR is still difficult to differentiate, with a high need for immunosuppression in both. DSAs may precede development of severe disease and pathology features on the graft: relationship and correlation need to be better investigated with larger groups before and after Tx. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Fiber structure formation in melt spinning of bio-based aliphatic co-polyesters
NASA Astrophysics Data System (ADS)
Qin, Qing; Takarada, Wataru; Kikutani, Takeshi
2015-05-01
High-speed melt spinning of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) with the 3-hydroxyhexanoate composition of 5.4 mol% was carried out. Melting temperature of this polymer is 141.5°C. It has been reported that PHBH fibers of good appearance can be prepared through the melt spinning process only when extrusion temperature is lower than the melting temperature of pure PHB (176 °C). The high-speed melt spinning experiment in this study revealed that the crystallization of PHBH proceeded at high take-up velocities even when the extrusion temperature was higher than the melting temperature of PHB. This result is considered to be due to the enhancement of crystallization through the application of high tensile stress to the molten polymer in the spinning line. As-spun fibers showed sufficiently high mechanical properties. On the other hand, crystalline orientation of α-form crystal increased with an increase in the take-up velocity and the existence of a small amount of β-form crystals was detected at high take-up velocities. This is another indication for the occurrence of crystallization under high tensile stress.
Kugel, Alex; He, Jie; Samanta, Satyabrata; ...
2012-08-27
Here, a series of poly(1,9-nonamethylene adipamide-co-1,9-nonamethylene terephthalamide) copolymers were produced using melt polymerization and the thermal properties, crystal structure, and moisture uptake characterized. The results confirmed that the copolymers exhibit isomorphism. As expected, glass transition temperature and the apparent melting temperature increased with increasing terephthalmide content. Using the difference in the apparent melting temperature to the crystallization temperature as a measure of relative crystallization rate, it was observed that crystallization rate decreased as the terephthalamide content of the copolymer was increased from 0 to 50 mole percent but then sharply increased when increased beyond 50 mole percent. This behavior maymore » be the result of extensive inter- and intramolecular interactions in the melt associated with terephthalmide units in the polymer chain that nucleate crystallization upon cooling below the equilibrium melting temperature. Comparing the thermal properties of copolymers possessing an excess of terephthalmide units to the commodity polyamide Nylon 6,6, it is believed that these copolymers may have utility as partially renewable engineering thermoplastics.« less
Main error factors, affecting inversion of EM data
NASA Astrophysics Data System (ADS)
Zuev, M. A.; Magomedov, M.; Korneev, V. A.; Goloshubin, G.; Zuev, J.; Brovman, Y.
2013-12-01
Inversions of EM data are complicated by a number of factors that need to be taken into account. These factors might contribute by tens of percents in data values, concealing responses from target objects, which usually contribute at the level of few percents only. We developed the exact analytical solutions of the EM wave equations that properly incorporate the contributions of the following effects: 1) A finite source size effect, where conventional dipole (zero-size) approximation brings 10-40% error compare to a real size source, needed to provide adequate signal-to-noise ratio. 2) Complex topography. A three-parametrical approach allows to keep the data misfits in 0.5% corridor while topography effect might be up to 40%. 3) Grounding shadow effect, caused by return ground currents, when Tx-line vicinity is horizontally non-uniform. By keeping survey setup within some reasonable geometrical ratios, the shadow effect comes to just one frequency-independent coefficient, which can be excluded from processing by using logarithmical derivatives. 4) Layer's wide spectral range effect. This brings to multi-layer spectral overlapping, so each frequency is affected by many layers; that requires wide spectral range processing, making the typical 'few-frequency data acquisition' non-reliable. 5) Horizontal sensitivity effect. The typical view at the target signal, reflected from a Tx-Rx mid-point is valid only for a ray approximation, reliable in a far-field zone. Unlike this, the real EM surveys usually work in near-field zone. Thus Tx-Rx mid-point does not represent the layer, so a sensitivity distribution function must be computed for each layer for the following 3D-unification process. 6) Wide range Rx-directions from mid-line Tx. Survey terrain often prevents placing Rx perpendicular to Tx-line, and even small deviations without proper corrections cause a significant inaccuracy. A radical simplification of the effect's description becomes possible after applying a special Angular Theorem. 7) Apparent conductivity spectral splitting factor. For some of the inversion approaches an averaged Earth's conductivity σA(ω) is the first step for the inversion to stratified Earth. The related spectral response from the loop-source splits such σA onto two branches: σA(ωHigh) and σA(ωLow), similar to early and late resistivities in time domain processing. 8) Calibration factor. A manufacturer-based internal calibration often leads to many percents of non-controllable systematic error at low and high frequency ends, as well as temperature changes. A special approach allows an external pre-survey calibration to achieve the required accuracy.
NASA Astrophysics Data System (ADS)
Rinkevich, A. B.; Nemytova, O. V.; Perov, D. V.; Samoylovich, M. I.; Kuznetsov, E. A.
2018-04-01
High-temperature heat treatment has valuable impact on the structure and physical properties of artificial crystals with 3d metal and palladium particles. Artificial crystals are obtained by means of introduction of particles into the interspherical voids of opal matrices. The magnetic properties are studied at the temperatures ranging from 2 to 300 K and in fields up to 350 kOe. Microwave properties are investigated in the millimeter frequency range. The complex dielectric permittivity of several nanocomposites is measured. The influence of heat treatment up to 960 °C on the structure of artificial crystals is clarified.
High quality factor single-crystal diamond mechanical resonators
NASA Astrophysics Data System (ADS)
Ovartchaiyapong, P.; Pascal, L. M. A.; Myers, B. A.; Lauria, P.; Bleszynski Jayich, A. C.
2012-10-01
Single-crystal diamond is a promising material for microelectromechanical systems (MEMs) because of its low mechanical loss, compatibility with extreme environments, and built-in interface to high-quality spin centers. But its use has been limited by challenges in processing and growth. We demonstrate a wafer bonding-based technique to form diamond on insulator, from which we make single-crystal diamond micromechanical resonators with mechanical quality factors as high as 338 000 at room temperature. Variable temperature measurements down to 10 K reveal a nonmonotonic dependence of quality factor on temperature. These resonators enable integration of single-crystal diamond into MEMs technology for classical and quantum applications.
NASA Astrophysics Data System (ADS)
Luo, Laihui; Dietze, Matthias; Solterbeck, Claus-Henning; Luo, Haosu; Es-Souni, Mohammed
2013-12-01
Single crystals based on solid solutions of lead-magnesium-niobate (PMN) and lead titanate (PT) have emerged as highly promising multifunctional systems combining piezoelectric, pyroelectric, and electro-optic properties that surpass by far those of the best known lead-zirkonium-titanate ceramics. In this paper we present new findings on how the phase transition temperature and the dielectric and ferroelectric properties can be tuned depending on crystal composition, orientation, and thermoelectrical treatment. Mn-doped and pure 0.72PbMg1/3Nb2/3O3-0.28PbTiO3 (0.72PMN-0.28PT) single crystals with ⟨111⟩ and ⟨001⟩ orientations were investigated. A special attention was devoted to field cooling (FC), i.e., cooling under electric field from different temperatures. The results illustrate different findings that were not reported before: the Curie temperature, i.e., ferroelectric-paraelectric transition temperature, is enhanced after field cooling of the Mn-doped, ⟨001⟩-oriented crystal while such a shift is not observed in the ⟨111⟩-oriented and the non-doped crystals. In addition, substantial polarization suppression occurs in the Mn-doped crystals upon FC from high temperature regardless of orientation. Based on piezoforce microscopy of the domain structure that shows suppression of domain growth following field cooling from 200 °C, we propose a mechanism for polarization suppression based on domain pinning by charged defects. The practical importance of our results lies in showing the opportunity offered by a proper choice of crystal composition and poling conditions for tuning the functional properties of PMN-PT single crystals for a specific application. This should contribute to the understanding of their properties towards advanced sensor and transducers devices.