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High Energy (high + energy)
Terms modified by High Energy Selected AbstractsSEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIESJOURNAL OF PHYCOLOGY, Issue 3 2001Article first published online: 24 SEP 200 Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source] SEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIESJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 9 OCT 200 Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source] High energy and high excitementASTRONOMY & GEOPHYSICS, Issue 1 2001Peter Bond Peter Bond reports on exciting discoveries in the high-energy universe and rock-solid signs of water on Mars. [source] Strong localization of EM waves using open cavities made of left-handed transmission-line mediaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2006Yao Qin Abstract Open cavities are investigated using properly designed right-handed (RH) and left-handed (LH) transmission-line media (TLM), with detailed formulations to design TLM. We demonstrate large fields and high energies are concentrated at the center because of the resonance, which is a strong localization of electromagnetic waves and energies. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1662,1665, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21689 [source] High-energy neutrino emission from low-mass microquasarsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2010J. F. Zhang ABSTRACT In this paper we study the high-energy neutrino emission from low-mass microquasars (LMMQs) by assuming that an acceleration region for particles is located in the inner jet, based on the framework of a hadronic jet model. Adopting the parametrized formulae for inelastic pp interactions and the recent p, parametrizations, we calculate the spectral energy distributions (SEDs) of various photon and neutrino spectra. Furthermore, we also consider the electromagnetic cascade processes due to ,, absorption. We then apply the jet model to the microquasar (MQ) GX 339,4, and calculate the expected neutrino event rate for three years of observations using the newest effective area of the KM3NeT detector in the Mediterranean Sea. The resulting results indicate that (1) photon spectra can roughly reproduce observations from radio to X-ray energies, and can also predict emission fluxes at high and very high energies (VHE); (2) GX 339,4 is a potential neutrino source, neutrinos from which are likely to be identified with some years of observations from the next-generation -scale neutrino telescopes. [source] GRS 1915+105: the distance, radiative processes and energy-dependent variabilityMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2005Andrzej A. Zdziarski ABSTRACT We present an exhaustive analysis of five broad-band observations of GRS 1915+105 in two variability states, , and ,, observed simultaneously by the Proportional Counter Array (PCA) and High-Energy X-ray Timing Experiment (HEXTE) detectors aboard the Rossi X-ray Timing Explorer, and the Oriented Scintillation Spectrometer Experiment (OSSE) detector aboard the Compton Gamma-ray Observatory. We find all the spectra well fitted by Comptonization of disc blackbody photons, with very strong evidence for the presence of a non-thermal electron component in the Comptonizing plasma. Both the energy and the power spectra in the , state are typical of the very high/intermediate state of black hole binaries. The spectrum of the , state is characterized by a strong blackbody component Comptonized by thermal electrons and a weak non-thermal tail. We then calculate rms spectra (fractional variability as functions of energy) for the PCA data. We accurately model the rms spectra by coherent superposition of variability in the components implied by the spectral fits, namely a less variable blackbody and more variable Comptonization. The latter dominates at high energies, resulting in a flattening of the rms at high energies in most of the data. This is also the case for the spectra of the quasi-periodic oscillations present in the , state. Then, some of our data require a radial dependence of the rms of the disc blackbody. We also study the distance to the source, and find d, 11 kpc as the most likely value, contrary to a recent claim of a much lower value. [source] On the accretion geometry of Cyg X-1 in the low/hard stateMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2003F. Eugenio Barrio ABSTRACT We fit the broad-band RXTE PCA and HEXTE spectrum of Cyg X-1 from 3,200 keV with reflection models which calculate the vertical ionization structure of an X-ray illuminated disc. We consider two geometries corresponding to a truncated disc/inner hot flow and magnetic flares above an untruncated disc. Both models are able to fit the PCA 3,20 keV data, but with very different spectral components. In the magnetic flare models the 3,20 keV PCA spectrum contains a large amount of highly ionized reflection, while in the truncated disc models the amount of reflection is rather small. The Compton downscattering rollover in reflected emission means that the magnetic flare models predict a break in the spectrum at the high energies covered by the HEXTE bandpass which is not seen. By contrast, the weakly illuminated truncated disc models can easily fit the 3,200 keV spectra. [source] Focusing high energy X-rays with stacked Fresnel zone platesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2007I. Snigireva Abstract Stacking technique was developed in order to increase focusing efficiency of Fresnel zone plates at high energies. Two identical Si chips each of which containing Fresnel zone plates were used for stacking. Alignment of the chips was achieved by on-line observation of the moiré pattern from the two zone plates. The formation of moiré patterns was studied theoretically and experimentally at different experimental conditions. To provide the desired stability Si-chips with zone plates were bonded together with slow solidification speed epoxy glue. Technique of angular alignment in order to compensate a linear displacement in the process of gluing was proposed. Two sets of stacked FZPs were produced and experimentally tested to focus 15 and 50 keV X-rays. Gain in the efficiency by factor 2.5 was demonstrated at 15 keV. Focal spot of 1.8 ,m vertically and 14 ,m horizontally with 35% efficiency was measured at 50 keV. Forecast for the stacking of nanofocusing Fresnel zone plates was discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Time-resolved spectroscopy in an undoped GaN (1-101)PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2008Eunhee Kim Abstract Time-resolved photoluminescence spectroscopy was performed at 77 K in a GaN (1-101) grown on a 7 degree off-axis (001) Si substrate. The sample was grown by metal-organic-vapour-phase-epitaxy (MOVPE) and was un-intentionally doped with O, C and Si. By using photoluminescence intensity correlation method, the energy relaxation process of the photogenerated carriers near the band edge was investigated in pico-second regime. The correlation signal was represented by a single exponential decay curve and the energy relaxation time was determined, which depended strongly on the kinetic energy of the excess carriers. At low energies, the relaxation time was around 700 ps, while it was as short as a few ps at the highest energy under study. The correlation signals obtained for carriers of which kinetic energy was less than 80 meV showed an anti-correlation behaviour suggesting the occurrence of carrier accumulation. The time constants for the accumulation were of several picoseconds depending on the kinetic energy, which was nearly equal to the decay time constants determined at high energies. This fact shows that the energy relaxation at high energies is controlled by the emission of an LO phonon. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Clinical Trial of Dual Treatment with an Ablative Fractional Laser and a Nonablative Laser for the Treatment of Acne Scars in Asian PatientsDERMATOLOGIC SURGERY, Issue 7 2009SANGEUN KIM MD BACKGROUND Many methods have been proposed for the treatment of acne scars, with variable cosmetic results. Nonablative skin resurfacing is one method that has been proposed. Because of a need for more noticeable clinical improvements, the ablative fractional laser was recently introduced. OBJECTIVE To reduce complications and improve the results of ablative fractional laser resurfacing by combining this treatment of acne scars with nonablative lasers. METHODS A series of 20 patients (skin phototypes IV,V) with atrophic facial acne scars were randomly divided into two groups that received three successive monthly treatments with an ablative fractional laser using high (group A) and low (group B) energy on one facial half and an ablative fractional laser with low energy plus a nonablative resurfacing laser on the other facial half. Patients were evaluated using digital photography at each treatment visit and at 3 months postoperatively. Clinical assessment scores were determined at each treatment session and follow-up visit. RESULTS Although the use of the ablative fractional laser with high energy resulted in an improvement in patients' acne scars, the combination of ablative fractional laser resurfacing and nonablative laser resurfacing yielded the best results, as assessed in photographs as well as by the overall appearance of the acne scars. With the combination method, fewer complications were observed. [source] Results of a Survey of 5,700 Patient Monopolar Radiofrequency Facial Skin Tightening Treatments: Assessment of a Low-Energy Multiple-Pass Technique Leading to a Clinical End Point AlgorithmDERMATOLOGIC SURGERY, Issue 8 2007FRCP, FRCPC, JEFFREY S. DOVER MD INTRODUCTION Monopolar radiofrequency is an effective means of nonsurgical facial skin tightening. OBJECTIVE The objective of this study was to determine whether using larger tips at lower energy and multiple passes, using patient feedback on heat sensation and treating to a clinical end point of visible tightening, would yield better results than single passes with small tips at high energy, as measured by patient and physician satisfaction. METHODS Fourteen physicians from four specialties were surveyed to determine the answers to the following three questions. (1) Is patient's feedback on heat sensation a valid and preferred method for optimal energy selection? (2) Do multiple passes at moderate energy settings yield substantial and consistent efficacy? (3) Is treating to a clinical end point of visible tightening predictable of results? RESULTS A total of 5,700 patient treatments were surveyed. Comparisons were made using the original algorithm of high-energy, single pass to the new algorithm of lower energy and multiple passes with visible tightening as the end point of treatment. Using the original treatment algorithm, 26% of patients demonstrated immediate tightening, 54% observed skin tightening 6 months after treatment, 45% found the procedure too painful, and 68% of patients found the treatment results met their expectations. With the new multiple-pass algorithm, 87% observed immediate tightening, 92% had the tightening six months after treatment, 5% found the procedure too painful, while 94% found the treatment results met their expectations. CONCLUSIONS Patient feedback on heat sensation is a valid, preferable method for optimal energy selection in monopolar radiofrequency skin-tightening treatments. [source] Analysis of urinary metabolites for metabolomic study by pressurized CECELECTROPHORESIS, Issue 23 2007Guoxiang Xie Abstract A new approach for the metabolomic study of urinary samples using pressurized CEC (pCEC) with gradient elution is proposed as an alternative chromatographic separation tool with higher degree of resolution, selectivity, sensitivity, and efficiency. The pCEC separation of urinary samples was performed on a RP column packed with C18, 5,,m particles with an ACN/water mobile phase containing TFA. The effects of the acid modifiers, applied voltage, mobile phase, and detection wavelength were systematically evaluated using eight spiked standards, as well as urine samples. A typical analytical trial of urine samples from Sprague Dawley (S.D.) rats exposed to high-energy diet was carried out following sample pretreatment. Significant differences in urinary metabolic profiles were observed between the high energy diet-induced obesity rats and the healthy control rats at the 6th,wk postdose. Multivariate statistical analysis revealed the differential metabolites in response to the diet, which were partially validated with the putative standards. This work suggests that such a pCEC-based separation and analysis method may provide a new and cost-effective platform for metabolomic study uniquely positioned between the conventional chromatographic tools such as HPLC, and hyphenated analytical techniques such as LC-MS. [source] The Effects of Steroid Hormones on the Transcription of Genes Encoding Enzymes of Oxidative PhosphorylationEXPERIMENTAL PHYSIOLOGY, Issue 1 2003Klaus Scheller Regulation of energy metabolism is one of the major functions of steroid hormones. In this process, mitochondria, by way of oxidative phosphorylation, play a central role. Depending on the energy needs of the cell, on the tissue, on the developmental stage and on the intensity of the hormonal stimulus, the response can be an activation of pre-existing respiratory chain components, an increased transcription of nuclear-encoded and/or mitochondrial-encoded respiratory chain enzyme (OXPHOS) genes and of biosynthesis of the respective enzyme subunits or, in extreme cases of high energy needs, an increase in the number of mitochondria and mitochondrial DNA content per cell. Some of the hormonally regulated systems involving effects on nuclear and mitochondrial OXPHOS genes are reviewed in this paper. The possible molecular mechanisms of steroid hormone action on nuclear and mitochondrial gene transcription and possible ways of coordination of transcription in these two separate cell compartments involving direct interaction of steroid receptors with hormone response elements in nuclear OXPHOS genes and in mitochondria and induction/activation of nuclear-encoded regulatory factors affecting mitochondrial gene transcription are presented. [source] Compact and Light Supercapacitor Electrodes from a Surface-Only Solid by Opened Carbon Nanotubes with 2,200 m2 g,1 Surface AreaADVANCED FUNCTIONAL MATERIALS, Issue 3 2010Tatsuki Hiraoka Abstract An approach is presented to make a "surface-only solid" with a surface area of 2,240,m2 g,1 (1,310,m2,cm,3), corresponding to 85% of the atoms constituting a surface, by opening single-walled carbon nanotube forests and solids via controlled oxidation. The controllability of the approach is demonstrated by tailoring the hole size to match the guest molecule, for example, nitrogen, fullerene, or solvated ions. These features make the surface-only solid an ideal vessel for material and energy storage, as demonstrated by its use for electrodes to realize a light and compact supercapacitor with high energy (24.7,W h kg,1) and power (98.9,kW kg,1) densities, exceeding those of activated carbon (16.9,W h kg,1 and 35.7,kW kg,1). [source] Negative (and very low) thermal expansion in ReO3 from 5 to 300,KJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2009Monica Dapiaggi This paper reports the accurate measurement of the ReO3 cell parameter as a function of temperature. The thermal expansion is confirmed to be negative over most of the temperature range from 5 to 300,K. The main problems with the measurements are the very small variations (in the range of 10,5,Å) in the cell parameter at each temperature, requiring tight control of the stability and reliability of instrumental effects. In particular, achieving monochromator stability over time might be challenging with the high energy and high beam current variations of a third-generation synchrotron facility. On the other hand, such effects are usually checked by the addition of silicon as an internal standard, but the accuracy (and precision) of the published thermal expansion (which is not certified) might not be sufficient for its use when dealing with very small cell parameter variations. [source] Combined use of crystalline salt forms and precipitation inhibitors to improve oral absorption of celecoxib from solid oral formulationsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2007Héctor R. Guzmán Abstract Biopharmaceutical evaluation of crystalline celecoxib salts in novel solid formulations, which were designed to simultaneously facilitate dissolution and inhibit precipitation in vitro, showed fast and complete absorption in beagle dogs at doses up to 7.5 mg/kg orally. In contrast, 5 mg/kg celecoxib in the form of Celebrex® showed approximately 40% absolute bioavailability in a cross-over experiment. An in vitro,in vivo correlation was observed in dog, and a threshold level of in vitro dissolution needed to maximize in vivo performance was highlighted. Oral bioavailability was limited in the absence of excipient combinations that delayed precipitation of celecoxib free acid as the salt neutralized in the GI fluid. Formulations of crystal forms having high energy (a ,spring'), thus transiently increasing solubility in aqueous solution relative to the free acid, combined with excipients functioning as precipitation inhibitors (,parachutes') were shown to provide both enhanced dissolution and high oral bioavailability. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 2686,2702, 2007 [source] Microenvironmental pH modulation in solid dosage formsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2007Sherif I. Farag Badawy Abstract There are many reports in the literature referring to the effect of ,microenvironmental pH' on solid dosage form performance, particularly stability and dissolution profiles. Several techniques have been proposed for the measurement of the microenvironmental pH. Those techniques use certain assumptions and approximations and many of them employ a solution calibration curve of a probe to predict hydrogen ion activity in a substantially dry solid. Despite the limitation of the methodology, it is clear from the literature that microenvironmental pH has a significant impact on stability of compounds which demonstrate pH dependent stability in solution. Degradation kinetics of such compounds, and in some cases degradation profile as well, are dependent on the microenvironmental pH of the solid. Modulation of the microenvironmental pH through the use of pH modifiers can hence prove to be a very effective tool in maximizing solid dosage form stability. Judicial selection of the appropriate pH modifier, its concentration and the manufacturing process used to incorporate the pH modifier is necessary to enhance stability. Control of microenvironmental pH to maximize stability can be achieved without the use of pH modifier in some cases if an appropriate counter ion is used to provide an inherently optimal pH for the salt. Microenvironmental pH modulation was also shown to control the dissolution profile of both immediate and controlled release dosage forms of compounds with pH dependent solubility. The pH modifiers have been used in conjunction with high energy or salt forms in immediate release formulations to minimize the precipitation of the less soluble free form during initial dissolution. Additionally, pH modifiers were utilized in controlled release dosage forms of weakly basic drugs which exhibit diminished release in dissolution media with high pH. The incorporation of acidic pH modifiers in the controlled release formulation increases the solubility of the basic drug even as the high pH dissolution medium enters into the dosage form hence increasing drug release rate. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 948,959, 2007 [source] SEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIESJOURNAL OF PHYCOLOGY, Issue 3 2001Article first published online: 24 SEP 200 Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source] SEAWEED ABUNDANCE AND DIVERSITY IN HIGH ENERGY AND LOW ENERGY AREAS AT PORT ARANSAS, TEXAS JETTIESJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 9 OCT 200 Agan, J. C. & Lehman, R. L. Department of Physical and Life Sciences, Texas A&M University-Corpus Christi 6300 Ocean Dr., Corpus Christi, TX 78412 USA Benthic algal sampling from high and low energy zones at a selected site on the south jetty at Port Aransas, Texas was completed between April 1999 and February 2000. Species composition and seasonal periodicity in relation to temperature and salinity fluctuations were determined. Dominant plants throughout the year included Bryocladia cuspidata, Bryocladia thyrsigera, Gelidium pusillum, Centroceras clavulatum, Ulva fasciata, and Padina gymnospora. The Rhodophyta dominated species coverage, along with biomass accumulation, although Chlorophyta species accrued the greatest biomass on the high energy side in April and June sampling. Chlorophyta are important to benthic coverage and biomass in the shallowest of waters, despite being fewer in species richness. Phaeophyta species including Petalonia fascia, Hincksia mitchelliae, and Ectocarpus siliculosus were found only during the cooler months. Padina gymnospora was the one exception as it was collected year-round. Results indicate that a greater Rhodophyta abundance was found on the channel side (low energy), where as, the surf side (high energy) contained a greater Chlorophyta abundance. Phaeophyta abundance for both high and low energy sites were comparable possibly due to the greater depth of water in which they are located. Little variance occurred in average biomass accumulation throughout the year. Highest biomass was in August (216.613g dry weight) with lowest occurring in April (107.4205g dry weight). [source] CHARACTERIZATION OF AGGLOMERATION PROCESS AS A FUNCTION OF MOISTURE CONTENT USING A MODEL FOOD POWDERJOURNAL OF TEXTURE STUDIES, Issue 1 2006S. MUKHERJEE ABSTRACT A model food-powder system using rice flour of different moisture contents (11 to 22%) was used to study rheological behavior by employing a powder rheometer to obtain maximum force, energy for compression and decompression. The latter parameters were sensitive at moisture contents of ,18%. The compacted mass, obtained using a rotary punch-tableting machine, was subjected to compression testing to determine the maximum force and firmness of the compressed tablets. These two parameters increased markedly above the 17% moisture content. A significant (P , 0.01) relationship between energy for compression for powder and firmness of compacted mass indicated that an adequate integrity of the product could be achieved when a powder requires high energy for compression but low energy for decompression. A modified version of the Hausner ratio, often used to characterize the extent of compactness, was proposed that included a correction factor for loss of moisture during compaction. [source] Theoretical Prediction of Post-Spinel Phases of Silicon NitrideJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2002Kazuyoshi Tatsumi New phases of Si3N4 that may be stable at higher pressure than spinel have been searched using a first-principles plane-wave pseudopotential method. The CaTi2O4 -type phase is found to be the prime candidate for the post-spinel phase among six phases selected on the analogy to high-pressure oxides. The phase transformation from the spinel is predicted to occur at 210 GPa. All silicon atoms of the new phase are coordinated by six anions, similar to the case of the high-pressure forms of SiO2 and SiC. Because of its high energy at zero pressure, this new phase may be difficult to quench. The bandgap increases with an increase of pressure when compared in the same polymorph. However, the bandgap and the net charge decrease in the order of ,, spinel, and CaTi2O4 -type phases at zero pressure. The theoretical bulk modulus of the CaTi2O4 -type phase is comparable with that of spinel. [source] The efficiency of laser for the treatment of Ehlers,Danlos syndromeLASERS IN SURGERY AND MEDICINE, Issue 2 2005Daniel F. Mueller MD Abstract Background and Objectives A 61-year-old woman presented herself with extensive elastosis of the facial skin caused by Ehlers,Danlos syndrome (EDS). Study Design/Materials and Methods Two laser skin resurfacings reduced the wrinkles significantly better than the two preceding conventional facelifts. For the first time, we have been able to compare two treatments with different laser systems on the same patient. The first treatment was performed with a high energy pulsed CO2 laser, which has been in use for 8 years. The second treatment was performed by us using the latest technology CO2/erbium:YAG combination laser. Results/Conclusion Resulting in a similar degree of wrinkle reduction, the treatment with the combination laser markedly reduced the duration of the healing process and erythema phase. Lasers Surg. Med. 36:76,78, 2005. © 2005 Wiley-Liss, Inc. [source] Weight control and physical activity in cancer preventionOBESITY REVIEWS, Issue 1 2002Franca Bianchini Summary Overweight and obesity have reached epidemic dimensions worldwide, mainly due to consumption of high energy diets and increased sedentary behaviour. Overweight and insufficient physical activity are clearly associated with cardiovascular diseases and type 2 diabetes. Evidence is also accumulating that they may also increase cancer risk, particularly in the colon, breast and endometrium. This effect seems to be mediated by alterations in the metabolism of endogenous hormones, including sex steroids and insulin, and levels of insulin-like growth factor(IGF)-I and IGF-binding proteins. In light of the beneficial effects of weight control and physical activity for cancer prevention, a healthy lifestyle, keeping a low body weight and exercising most days of the week, is recommended. [source] Subthreshold Test Pulses Versus Low Energy Shock Delivery to Estimate High Energy Lead Impedance in Implanted Cardioverter Defibrillator PatientsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p2 2003DIRK VOLLMANN VOLLMANN, D., et al.: Subthreshold Test Pulses Versus Low Energy Shock Delivery to Estimate High Energy Lead Impedance in Implanted Cardioverter Defibrillator Patients. The high energy lead impedance is valuable for detecting lead failure in ICDs, but until recently shock delivery was necessary for high energy impedance measurement. This study compared the use of subthreshold test pulses and low energy test shocks to estimate the high energy impedance. Immediately after implantation of Ventak Prizm ICDs in 29 patients, the lead impedance was measured with five subthreshold (0.4 ,J) test pulses, 5 low energy (1.1 J) shocks, and two to three high energy(16 ± 4.5 J)shocks. The mean impedances measured using high energy shocks, low energy shocks, and subthreshold pulses were42.0 ± 7.3 ,, 46.5 ± 8.1 ,, and42.4 ± 7.1 ,, respectively. The impedances measured using high and low energy shocks differed significantly(P <0.0001), while those obtained by high energy shocks and low energy pulses did not(P = 0.63). According to the Pearson correlation coefficient, the impedance measurements with subthreshold pulses and low energy shocks were both closely correlated(P < 0.0001)with impedance values determined with high energy shocks. However, while the impedance values tended to be higher when measured with low energy shocks, the concordance correlation coefficient (c) was higher for subthreshold test pulse versus high energy shock(c = 0.92)than for low versus high energy shock(c = 0.73). Furthermore, the intraindividual variability of impedance measurements was lower with subthreshold pulse measurements than with low energy shocks. Compared with low energy shocks, impedance measurement with subthreshold pulses has higher reproducibility and a higher correlation with the impedance obtained by high energy shock delivery. Safe and painless high energy impedance estimation with subthreshold pulses might, therefore, help to detect ICD lead failure during routine follow-up. (PACE 2003; 26:[Pt. II]:457,460) [source] A study of the effects of postcure treatments on polyester,melamine coating matricesPOLYMER ENGINEERING & SCIENCE, Issue 4 2006N.J.W. Gamage The effect of postcure high energy (,), ultraviolet (UV) and thermal treatment on the properties of polyester,melamine clearcoats of a range of compositions has been investigated. Two initial cure conditions were used, of which one was "optimally" cured and the other under-cured. It was found that postcure treatments, particularly , and UV, led to coatings of similar mechanical and thermal properties irrespective of initial cure, although the change in properties on postcure treatment was greater for the under-cured samples. The results were interpreted in terms of the effect of the treatments on the structure of the crosslinked matrices. The study suggests the possibility of the development of a dual-cure process for polyester,melamines, whereby cure optimization and property improvement can be achieved. This could also be used to "correct" for small variations in thermal cure levels brought about by adventitious on-line fluctuations in cure oven conditions. POLYM. ENG. SCI. 46:532,539, 2006. © 2006 Society of Plastics Engineers [source] Nanostructured Carbon and Carbon Nanocomposites for Electrochemical Energy Storage ApplicationsCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 2 2010Sheng Su Abstract Electrochemical energy storage is one of the important technologies for a sustainable future of our society, in times of energy crisis. Lithium-ion batteries and supercapacitors with their high energy or power densities, portability, and promising cycling life are the cores of future technologies. This Review describes some materials science aspects on nanocarbon-based materials for these applications. Nanostructuring (decreasing dimensions) and nanoarchitecturing (combining or assembling several nanometer-scale building blocks) are landmarks in the development of high-performance electrodes for with long cycle lifes and high safety. Numerous works reviewed herein have shown higher performances for such electrodes, but mostly give diverse values that show no converging tendency towards future development. The lack of knowledge about interface processes and defect dynamics of electrodes, as well as the missing cooperation between material scientists, electrochemists, and battery engineers, are reasons for the currently widespread trial-and-error strategy of experiments. A concerted action between all of these disciplines is a prerequisite for the future development of electrochemical energy storage devices. [source] | ||||||||||||||||||||||||||||||||||