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Luminescence of Er^(3+) in Oxyfluoride Transparent glass-Ceramics

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Journal of Rare Earths 2006年第6期24卷 699-705页

作者： Akira Ueda steven H Morgan Richard Mu Department of Physics Fisk University NashvilleTN 37208 USA

Erbium doped silicate, germanate, and tellurium-germanate oxyfluoride glasses were prepared in a bulk form. Through appropriate heat treatment of the as-prepared glasses, transparent glass-ceramics （TgCs） were obtained with the formation of β-PbF2：Er^3＋ nanocrystals in the glass matrix were confirmed by X-ray ***-defined diffraction peaks were observed in the samples after heat-treatment. The average crystal diameter of these precipitated crystals from full-width at half-maximum （FWHM） of the diffraction peak was estimated to be between 8 and 13 nm. Optical absorption, photoluminescence, and upconversion luminescence were measured on as-prepared glass and glass-ceramics. Luminescence spectra in the TgC samples revealed well-resolved, sharp stark-splitting peaks, which indicates that a majority of Er^3＋ ions has been incorporated into the crystalline phase of the nanocrystals. The intensity of the visible and near infrared luminescence mostly increases in TSg compared to that in the as-prepared glass. In 1.53 μm absorption and emission bands, the maximum absorption peak is blue-shifted from 1531 to 1507 nm, whereas the maximum emission peak is redshifted from 1535 to 1543 nm in TgC, as compared with that in glass. The bandwidth at half-maximum （BWHM） of the emission band is significantly broader in TgC than in glass, which is beneficial to the erbium-doped fiber amplifier （EDFA）. Upconversion luminescence was measured using 800 nm near-infrared light excitation. Drastically increased upconversion 1 was observed from the TgC as compared to that from their corresponding as-prepared glasses. In addition to a strong green emission centered at 545 nm because of ^4S3/2→^4I15/2 transition and a weaker red emission centered at 662 nm because of ^4F9/2→^4I15/2 transition, generally seen from the Er^3＋ doped glasses, two violet emissions centered at 410 nm because of ^2H9/2→^4I15/2 transition and centered at 379 nm because of ^4g11/2→^4I15/2 transition were also o

关键词： luminescence transparent glass-ceramics rare earths

Treating blood pressure to prevent strokes: The age factor

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World Journal of Cardiology 2013年第3期5卷 22-27页

作者： steven g Chrysant Department of Cardiology University of Oklahoma College of Medicine

The importance of systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP), on the incidence of coronary heart disease (CHD) and stroke are known. However, the importance of blood pressure (BP)-age shifts regarding the stroke incidence is not clearly known. The BP changes with the advancement of age from the predominance of DBP in the young to the predominance of SBP in the old. This change is due to the stiffening of the large arteries as a result of the aging process and the replacement of the elastic fibers with collagen fibers. This change results in the loss of compliance and the elastic recoil of these vessels leading to increase in pulse wave velocity, central SBP and widening of pulse pressure leading to an increased incidence of CHD and strokes. It has been demonstrated epidemiologically that the SBP rises linearly with age, whereas the DBP rises up to the age of 45-50 years, and then begins to decline after the age of 60 years leading to a progressive widening of PP. Several studies have shown an inverse relationship between DBP and CHD, whereas no such relationship has been demonstrated for stroke. However, a recent study showed an inverse relationship with DBP and stroke when it dropped below 71 mmHg in subjects 50 years of age or older. In contrast, there was a positive association between BP and stroke when both SBP and DBP were ≥ 71 mmHg. These findings suggest that intreating systolic hypertension in the elderly to reduce stroke risk, attention should be paid on the potential harm of low DBP and the widening of PP regarding CHD and stroke. The implications of BP shifts with age and the potential risks of low DBP regarding the risk of stroke will be discussed in this concise review.

关键词： Age Blood pressure Pulse pressure Stroke Age blood pressure interaction

Bloch surface eigenstates within the radiation continuum

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Light(Science & Applications) 2013年第1期2卷 113-118页

作者： Chia Wei Hsu Bo Zhen Song-Liang Chua steven g Johnson John D Joannopoulos Marin Soljacic Research Laboratory of Electronics Massachusetts Institute of TechnologyCambridgeMA 02139USA Department of Physics Harvard UniversityCambridgeMA 02138USA Department of Mathematics Massachusetts Institute of TechnologyCambridgeMA 02139USA

From detailed numerical calculations,we demonstrate that in simple photonic crystal structures,a discrete number of Bloch surface-localized eigenstates can exist inside the continuum of free-space *** to the free space causes the surface modes to leak,but the forward and back-reflected leakage may interfere destructively to create a perfectly bound surface state with zero *** perform analytical temporal coupled-mode theory analysis to show the generality of such phenomenon and its robustness from variations of system ***,time-reversal invariance,two-fold rotational symmetry and a perfectly reflecting boundary are necessary for these unique states.

关键词： bound state in continuum embedded eigenvalue photonic crystal surface mode

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Cherish your weeds

Molecular Plant 2022年第3期15卷 396-397页

作者： steven Dreissig Martin Mascher Institute of Agricultural and Nutritional Sciences Martin-Luther-University Halle-WittenbergHalle(Saale)Germany Leibniz Institute of Plant genetics and Crop Plant Research(IPK) SeelandOT GaterslebenGermany german Centre for Integrative Biodiversity Research(iDiv)Halle-Jena-Leipzig LeipzigGermany

The domestication of crops was a protracted process that extended over thousands of *** began approximately 12000 years ago and marked the onset of the Neolithic *** the Neolithic,human cultures transitioned from a hunter-gatherer lifestyle toward one of agriculture and *** process,however,was a long one,which spanned many human *** this period,many of today's most important crops were domesticated from wild *** include wheat,barley,rice,and maize.

关键词： crops weed settlement

Overview and Comparison of the IEEE EPON and ITU-T gPON Protocols

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China Communications 2007年第2期4卷 69-78页

作者： steven S.gorshe

Providing the "triple play" services of voice,video,and high-speed data access is an important way for carriers to increase their revenue and compete with other access providers such as the CATV *** most flexible and "future-proof" medium for providing triple play services is fiber,with its virtually unlimited bandwidth *** providing a direct optical connection between the CO and each subscriber is cost prohibitive, most optical access systems use a passive optical network (PON) to connect multiple subscribers to the same CO optical *** white paper provides a tutorial overview and comparison of the two most popular very high-speed PON access network standards:the ITU-T g. 984 series gigabit PON(gPON) and IEEE 802.3ah Ethernet PON(EPON) standards.

关键词：街面

Nutritional epigenetics education improves diet and attitude of parents of children with autism or attention deficit/hyperactivity disorder

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World Journal of Psychiatry 2024年第1期14卷 159-178页

作者： Renee J Dufault Katherine M Adler David O Carpenter steven g gilbert Raquel A Crider College of graduate Health Studies A.T.Still UniversityKirksvilleMO 63501United States Department of Research Food Ingredient and Health Research InstituteNaalehuHI 96772United States Department of Health Sciences University of New HavenWest HavenCT 06516United States Institute for Health and the Environment School of Public HealthState University of New YorkAlbanyNY 12222United States Department of Research Institute of Neurotoxicology and Neurological DisordersSeattleWA 98105United States Department of Statistics Food Ingredient and Health Research InstituteNaalehuHI 96772United States

BACKgROUND Unhealthy maternal diet leads to heavy metal exposures from the consumption of ultra-processed foods that may impact gene behavior across generations,creating conditions for the neurodevelopmental disorders known as autism and attention deficit/hyperactivity disorder(ADHD).Children with these disorders have difficulty metabolizing and excreting heavy metals from their bloodstream,and the severity of their symptoms correlates with the heavy metal levels measured in their *** may play a key role in helping parents reduce their ultra-processed food and dietary heavy metal intake by providing access to effective nutritional epigenetics *** To test the efficacy of nutritional epigenetics instruction in reducing parental ultra-processed food *** The study utilized a semi-randomized test and control group pretest-posttest pilot study design with participants recruited from parents having a learning-disabled child with autism or ***-two parents who met the inclusion criteria were randomly selected to serve in the test(n=11)or control(n=11)*** test group participated in the six-week online nutritional epigenetics tutorial,while the control group did *** efficacy of the nutritional epigenetics instruction was determined by measuring changes in parent diet and attitude using data derived from an online diet survey administered to the participants during the pre and post intervention *** intake scores were derived for both ultra-processed and whole/organic *** sample t-tests were conducted to determine any differences in mean diet scores within each *** There was a significant difference in the diet scores of the test group between the pre-and post-intervention *** parents in the test group significantly reduced their intake of ultra-processed foods with a preintervention diet score of 70(mean=5.385,SD=2.534)and a post-intervention diet score of 113(mean=8.692,SD=1.750)and the

关键词： Epigenomics Parenteral nutrition Autism Attention deficit/hyperactivity disorder Ultra-processed foods Heavy metals

Low rank approximation in g0W0 calculations

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Science China Mathematics 2016年第8期59卷 1593-1612页

作者： SHAO MeiYue LIN Lin YANg Chao LIU Fang DA JORNADA Felipe H. DESLIPPE Jack LOUIE steven g. Computational Research Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Mathematics University of California at BerkeleyBerkeleyCA 94720USA School of Statistics and Mathematics Central University of Finance and EconomicsBeijing 100081China Department of Physics University of California at BerkeleyBerkeleyCA 94720USA Materials Science Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA NERSC.Lawrence Berkeley National Laboratory Berkeley.CA 94720.USA

The single particle energies obtained in a Kohn-Sham density functional theory(DFT) calculation are generally known to be poor approximations to electron excitation energies that are measured in transport,tunneling and spectroscopic experiments such as photo-emission spectroscopy. The correction to these energies can be obtained from the poles of a single particle green's function derived from a many-body perturbation theory. From a computational perspective, the accuracy and efficiency of such an approach depends on how a self energy term that properly accounts for dynamic screening of electrons is approximated. The g_0W_0 approximation is a widely used technique in which the self energy is expressed as the convolution of a noninteracting green's function(g_0) and a screened Coulomb interaction(W_0) in the frequency domain. The computational cost associated with such a convolution is high due to the high complexity of evaluating W_0 at multiple frequencies. In this paper, we discuss how the cost of g_0W_0 calculation can be reduced by constructing a low rank approximation to the frequency dependent part of W_0. In particular, we examine the effect of such a low rank approximation on the accuracy of the g_0W_0 approximation. We also discuss how the numerical convolution of g_0 and W_0 can be evaluated efficiently and accurately by using a contour deformation technique with an appropriate choice of the contour.

关键词： density functional theory goW0 approximation Sternheimer equation contour deformation lowrank approximation

The VEgF signaling pathway in cancer: the road ahead

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Chinese Journal of Cancer 2013年第6期32卷 297-302页

作者： steven A. Stacker Marc g. Achen Tumour Angiogenesis Program Peter MacCallum Cancer Centre St. Andrews Place Sir Peter MacCallum Department of Oncology University of Melbourne

The vascular endothelial growth factor (VEgF) family of soluble protein growth factors consists of key mediators of angiogenesis and lymphangiogenesis in the context of tumor biology. The members of the family, VEgF-A (also known as VEgF), VEgF-B, VEgF-C, VEgF-D, and placenta growth factor (PlgF), play important roles in vascular biology in both normal physiology and pathology. The generation of a humanized neutralizing antibody to VEgF-A (bevacizumab, also known as Avastin) and the demonstration of its benefit in numerous human cancers have confirmed the merit of an anti-angiogenesis approach to cancer treatment and have validated the VEgF-A signaling pathway as a therapeutic target. Other members of the VEgF family are now being targeted, and their relevance to human cancer and the development of resistance to anti-VEgF-A treatment are being evaluated in the clinic. Here, we discuss the potential of targeting VEgF family members in the diagnosis and treatment of cancer.

关键词： VEgF-C 癌症治疗信号通路血管内皮生长因子 EgF家族肿瘤生物学道路胎盘生长因子

Exploring the reasons for the seasons using google Earth, 3D models, and plots

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International Journal of Digital Earth 2017年第6期10卷 582-603页

作者： Declan g.De Paor Mladen M.Dordevic Paul Karabinos Stephen Burgin Filis Coba steven J.Whitmeyer Departments of Physics and Ocean Earthand Atmospheric SciencesOld Dominion UniversityNorfolkVAUSA Department of geology and Environmental Science James Madison UniversityHarrisonburgVAUSA Department of geosciences Williams CollegeWilliamstownMAUSA Department of Curriculum and Instruction University of ArkansasFayettevilleARUSA Department of Physics Old Dominion UniversityNorfolkVAUSA

Public understanding of climate and climate change is of broad societal ***,misconceptions regarding reasons for the seasons abound amongst students,teachers,and the public,many of whom believe that seasonality is caused by large variations in Earth’s distance from the *** may be reinforced by textbook illustrations that exaggerate eccentricity or show an inclined view of Earth’s near-circular *** explanations that omit multiple factors influencing seasons,that do not mesh with students’experiences,or that are erroneous,hinder scientifically valid *** show that many teachers share their students’misconceptions,and even when they understand basic concepts,teachers may fail to appreciate the range of factors contributing to seasonal change,or their relative *** have therefore developed a learning resource using google Earth,a virtual globe with other useful,weather-and climate-related visualizations.A classroom test of 27 undergraduates in a public research university showed that 15 improved their test scores after the google Earth-based laboratory class,whereas 5 *** correct answers rose from 4.7/10 to 6/10,giving a paired t-test value of *** using google Earth,students are helped to segue to a heliocentric view.

关键词： Visualization geo-spatial science geobrowser earth observation 3-d representation