Raman phonon modes of zinc blende InxGa1-xN alloy epitaxial layers

Transverse-optical (TO) and longitudinal-optical (LO) phonons of zinc blende InxGa1-xN (0 less than or equal to x less than or equal to 0.31) layers are observed through first-order micro-Raman scattering experiments. The samples are grown by molecular-beam epitaxy on GaAs (001) substrates, and x-ray diffraction measurements are performed to determine the epilayer alloy composition. Both the TO and LO phonons exhibit a one-mode-type behavior, and their frequencies display a linear dependence on the composition. The Raman data reported here are used to predict the A(1) (TO) and E-1 (TO) phonon frequencies of the hexagonal InxGa1-xN alloy. (C) 1999 American Institute of Physics. [S0003-6951(99)01234-6].7581095109

Raman Phonon Modes Of Zinc Blende Inxga1 - Xn Alloy Epitaxial Layers

Transverse-optical (TO) and longitudinal-optical (LO) phonons of zinc blende InxGa1 - xN (0≤x ≤0.31) layers are observed through first-order micro-Raman scattering experiments. The samples are grown by molecular-beam epitaxy on GaAs (001) substrates, and x-ray diffraction measurements are performed to determine the epilayer alloy composition. Both the TO and LO phonons exhibit a one-mode-type behavior, and their frequencies display a linear dependence on the composition. The Raman data reported here are used to predict the A1 (TO) and E1 (TO) phonon frequencies of the hexagonal InxGa1 - xN alloy. © 1999 American Institute of Physics.75810951097Pankove, J.I., Moustakas, T., Gallium nitrides I (1998) Semiconductors and Semimetals, 50. , Academic, San Diego, CAShan, W., Walukiewicz, W., Haller, E.E., Little, B.D., Song, J.J., McCluskey, M.D., Johnson, N.M., Stall, R.A., (1998) J. Appl. Phys., 84, p. 4452Chichibu, S., Azuhata, T., Sota, T., Nakamura, S., (1997) Appl. Phys. Lett., 70, p. 2822Shan, W., Perlin, P., Ager J.W. III, Walukiewicz, W., Haller, E.E., McCluskey, M.D., Johnson, N.M., Bour, D.P., (1998) Appl. Phys. Lett., 73, p. 1613Chichibu, S., Azuhata, T., Sota, T., Nakamura, S., (1996) Appl. Phys. Lett., 69, p. 4188Narukawa, Y., Kawakami, Y., Funato, M., Fujita, S., Nakamura, S., (1997) Appl. Phys. Lett., 70, p. 981Orton, J.W., Foxon, C.T., (1998) Rep. Prog. Phys., 61, p. 1Abernathy, C.R., MacKenzie, J.D., Bharatan, S.R., Jones, K.S., Pearton, S.J., (1995) Appl. Phys. Lett., 66, p. 1632(1995) J. Vac. Sci. Technol. A, 13, p. 716Müllhäuser, J.R., Jenichen, B., Wassermeier, M., Brandt, O., Ploog, K.H., (1997) Appl. Phys. Lett., 71, p. 909Müllhäuser, J.R., Brandt, O., Trompert, A., Jenichen, B., Ploog, K.H., (1998) Appl. Phys. Lett., 73, p. 1230Holst, J., Hoffmann, A., Broser, I., Frey, T., Schöttker, B., As, D.J., Schikora, D., Lischka, K., (1999) MRS Internet J. Nitride Semicond. Res., 4 S1, pp. G23Feng, Z.C., Schurman, M., Tran, C.A., Salagaj, T., Karlicek, B., Ferguson, I., Stall, R.A., Pitt, G.D., (1998) Mater. Sci. Forum, 264-268, p. 1359Behr, D., Niebuhr, R., Obloh, H., Wagner, J., Bachem, K.H., Kaufmann, U., (1997) Mater. Res. Soc. Symp. Proc., 468, p. 213Osamura, K., Naka, S., Murakami, Y., (1975) J. Appl. Phys., 46, p. 3432Tabata, A., Lima, A.P., Teles, L.K., Scolfaro, L.M.R., Leite, J.R., Lemos, V., Schöttker, B., Lischka, K., (1999) Appl. Phys. Lett., 74, p. 362Tabata, A., Enderlein, R., Leite, J.R., Da Silva, S.W., Galzerani, J.C., Schikora, D., Kloidt, M., Lischka, K., (1996) J. Appl. Phys., 79, p. 4137Strite, S., Chandrasekhar, D., Smith, D.J., Sariel, J., Chen, H., Teraguchi, N., Morkoç, H., (1993) J. Cryst. Growth, 127, p. 204Ho, I., Stringfellow, G.B., (1996) Appl. Phys. Lett., 69, p. 2701Inushima, T., Yaguchi, T., Nagase, A., Iso, A., Shiraishi, T., (1996) Proceedings of the 6th Conference on Silicon Carbide and Related Materials, , Bristol(1996) Inst. Phys. Conf. Ser., 142, p. 971Dyck, J.S., Kash, K., Kim, K., Lambrecht, W.R.L., Hayman, C.C., Argoitia, A., Grossner, M.T., Angus, J.C., (1998) Mater. Res. Soc. Symp. Proc., 482, p. 549Yu, S., Kim, K.W., Bergman, L., Dutta, M., Stroscio, M.A., Zavada, J.M., (1998) Phys. Rev. B, 58, p. 15283Kwon, H.-J., Lee, Y.-H., Miki, O., Yamano, H., Yoshida, A., (1996) Appl. Phys. Lett., 69, p. 937Lee, M.-C., Lin, H.-C., Pan, Y.-C., Shu, C.-K., Ou, J., Chen, W.-H., Chen, W.-K., (1998) Appl. Phys. Lett., 73, p. 260

Evidence for phase-separated quantum dots in cubic InGaN layers from resonant Raman scattering

The emission of light in the blue-green region from cubic InxGa1-xN alloys grown by molecular beam epitaxy is observed at room temperature and 30 K. By using selective resonant Raman spectroscopy (RRS) we demonstrate that the emission;is due to quantum confinement effects taking place in phase-separated In-rich quantum dots formed in the layers. RRS data show that the In content of the dots fluctuates across the volume of the layers. We find that dot size and alloy fluctuation determine the emission wavelengths.84163666366

Performance of [(18)F]flutemetamol amyloid imaging against the neuritic plaque component of CERAD and the current (2012) NIA-AA recommendations for the neuropathologic diagnosis of Alzheimer's disease

INTRODUCTION: Performance of the amyloid tracer [(18)F]flutemetamol was evaluated against three pathology standard of truth (SoT) measures including neuritic plaques (CERAD "original" and "modified" and the amyloid component of the 2012 NIA-AA guidelines). METHODS: After [(18)F]flutemetamol imaging, 106 end-of-life patients who died underwent postmortem brain examination for amyloid plaque load. Blinded positron emission tomography scan interpretations by five independent electronically trained readers were compared with pathology measures. RESULTS: By SoT, sensitivity and specificity of majority image interpretations were, respectively, 91.9% and 87.5% with "original CERAD," 90.8% and 90.0% with "modified CERAD," and 85.7% and 100% with the 2012 NIA-AA criteria. DISCUSSION: The high accuracy of either CERAD criteria suggests that [(18)F]flutemetamol predominantly reflects neuritic amyloid plaque density. However, the use of CERAD criteria as the SoT can result in some false-positive results because of the presence of diffuse plaques, which are accounted for when the positron emission tomography read is compared with the 2012 NIA-AA criteria

Why Moral Expertise Needs Moral Theory

Discussions of the nature or possibility of moral expertise have largely proceeded in atheoretical terms, with little attention paid to whether moral expertise depends on theoretical knowledge of morality. Here I argue that moral expertise is more theory-dependent than is commonly recognized: Moral expertise consists, at least in part, in knowledge of the correct or best moral theory, and second, that knowledge of moral theory is essential to moral experts dispensing expert counsel to non-experts. Moral experts would not be moral experts absent knowledge of moral theory, nor could they play the testimonial role we would expect them to play in moral inquiry and deliberation absent such knowledg

X-ray fluorescence analysis of long-term changes in the levels and distributions of trace elements in the rat brain following mechanical injury

This paper describes the results of the application of X-ray fluorescence microscopy to the qualitative, topographic and quantitative elemental analysis of nervous tissue from rats with neocortical brain injury. The tissue samples were analyzed with a 15 μm beam defined by the size of the polycapillary focus. Raster scanning of the samples generated 2D cartographies, revealing the distributions of elements such as P, S, Cl, K, Ca, Fe, Cu, and Zn. Special emphasis was placed on the analysis of the areas neighboring the lesion site and the hippocampal formation tissue. The results obtained for rats with mechanical brain injuries were compared with those recorded for controls and animals with pilocarpine-induced seizures. There were no significant differences in the elemental compositions of gray and white matter between injured and uninjured brain hemispheres. A higher level of Ca was observed in the gray matter of both of the hemispheres in brains with neocortical injuries. A similar relation was noticed for Fe in the white matter. A comparative study of hippocampal formation tissue showed a statistically significant decrease in the mass per unit area of P in the dentate gyrus (DG) and the hilus (H) of DG for animals with brain lesions in comparison with the control group. Analogous relations were found for Cu in the DG and Zn in sector 3 of Ammon’s horn (CA3) and the DG. It is important to note that identical changes in the same areas were observed for animals with pilocarpine-induced seizures in our previous study

IMPULSE: the impact of gender on the presentation and management of aortic stenosis across Europe.

AIMS: There is an increasing awareness of gender-related differences in patients with severe aortic stenosis and their outcomes after surgical aortic valve replacement (SAVR) and transcatheter aortic valve implantation (TAVI). METHODS: Data from the IMPULSE registry were analysed. Patients with severe aortic stenosis (AS) were enrolled between March 2015 and April 2017 and stratified by gender. A subgroup analysis was performed to assess the impact of age. RESULTS: Overall, 2171 patients were enrolled, and 48.0% were female. Women were characterised by a higher rate of renal impairment (31.7 vs 23.3%; p<0.001), were at higher surgical risk (EuroSCORE II: 4.5 vs 3.6%; p=0.001) and more often in a critical preoperative state (7.0vs 4.2%; p=0.003). Men had an increased rate of previous cardiac surgery (9.4 vs 4.7%; p<0.001) and a reduced left ventricular ejection fraction (4.9 vs 1.3%; p<0.001). Concomitant mitral and tricuspid valve disease was substantially more common among women. Symptoms were highly prevalent in both women and men (83.6 vs 77.3%; p<0.001). AVR was planned in 1379 cases. Women were more frequently scheduled to undergo TAVI (49.3 vs 41.0%; p<0.001) and less frequently for SAVR (20.3 vs 27.5%; p<0.001). CONCLUSIONS: The present data show that female patients with severe AS have a distinct patient profile and are managed in a different way to males. Gender-based differences in the management of patients with severe AS need to be taken into account more systematically to improve outcomes, especially for women

Dapsone induced cholangitis as a part of dapsone syndrome: a case report

BACKGROUND: Dapsone can rarely cause a hypersensitivity reaction called dapsone syndrome, consisting of fever, hepatitis, exfoliative dermatitis, lymphadenopathy and hemolytic anemia. Dapsone syndrome is a manifestation of the DRESS (drug rash with eosinophilia and systemic symptoms) syndrome which is a serious condition that has been reported in association with various drugs. Cholangitis in dapsone syndrome has not been reported so far in the world literature. CASE PRESENTATION: We report a patient who presented with fever, exfoliative dermatitis, jaundice and anemia within three weeks of starting of dapsone therapy. These features are typical of dapsone syndrome, which is due to dapsone hypersensitivity and is potentially fatal. Unlike previous reports of hepatitic or cholestatic injury in dapsone syndrome we report here a case that had cholangitic liver injury. It responded to corticosteroids. CONCLUSION: We conclude that cholangitis, though unusual, can also form a part of dapsone syndrome. Physicians should be aware of this unusual picture of potentially fatal dapsone syndrome

Search for time-dependent B0s - B0s-bar oscillations using a vertex charge dipole technique

We report a search for B0s - B0s-bar oscillations using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The analysis takes advantage of the electron beam polarization as well as information from the hemisphere opposite that of the reconstructed B decay to tag the B production flavor. The excellent resolution provided by the pixel CCD vertex detector is exploited to cleanly reconstruct both B and cascade D decay vertices, and tag the B decay flavor from the charge difference between them. We exclude the following values of the B0s - B0s-bar oscillation frequency: Delta m_s < 4.9 ps-1 and 7.9 < Delta m_s < 10.3 ps-1 at the 95% confidence level.Comment: 18 pages, 3 figures, replaced by version accepted for publication in Phys.Rev.D; results differ slightly from first versio

Agronomic Management of Indigenous Mycorrhizas

Many of the advantages conferred to plants by arbuscular mycorrhiza (AM) are associated to the ability of AM plants to explore a greater volume of soil through the extraradical mycelium. Sieverding (1991) estimates that for each centimetre of colonized root there is an increase of 15 cm3 on the volume of soil explored, this value can increase to 200 cm3 depending on the circumstances. Due to the enhancement of the volume of soil explored and the ability of the extraradical mycelium to absorb and translocate nutrients to the plant, one of the most obvious and important advantages resulting from mycorrhization is the uptake of nutrients. Among of which the ones that have immobilized forms in soil, such as P, assume particular significance. Besides this, many other benefits are recognized for AM plants (Gupta et al, 2000): water stress alleviation (Augé, 2004; Cho et al, 2006), protection from root pathogens (Graham, 2001), tolerance to toxic heavy metals and phytoremediation (Audet and Charest, 2006; Göhre and Paszkowski, 2006), tolerance to adverse conditions such as very high or low temperature, high salinity (Sannazzaro et al, 2006), high or low pH (Yano and Takaki, 2005) or better performance during transplantation shock (Subhan et al, 1998). The extraradical hyphae also stabilize soil aggregates by both enmeshing soil particles (Miller e Jastrow, 1992) and producing a glycoprotein, golmalin, which may act as a glue-like substance to adhere soil particles together (Wright and Upadhyaya, 1998). Despite the ubiquous distribution of mycorrhizal fungi (Smith and Read, 2000) and only a relative specificity between host plants and fungal isolates (McGonigle and Fitter, 1990), the obligate nature of the symbiosis implies the establishment of a plant propagation system, either under greenhouse conditions or in vitro laboratory propagation. These techniques result in high inoculum production costs, which still remains a serious problem since they are not competitive with production costs of phosphorus fertilizer. Even if farmers understand the significance of sustainable agricultural systems, the reduction of phosphorus inputs by using AM fungal inocula alone cannot be justified except, perhaps, in the case of high value crops (Saioto and Marumoto, 2002). Nurseries, high income horticulture farmers and no-agricultural application such as rehabilitation of degraded or devegetated landscapes are examples of areas where the use of commercial inoculum is current. Another serious problem is quality of commercial available products concerning guarantee of phatogene free content, storage conditions, most effective application methods and what types to use. Besides the information provided by suppliers about its inoculum can be deceiving, as from the usually referred total counts, only a fraction may be effective for a particular plant or in specific soil conditions. Gianinazzi and Vosátka (2004) assume that progress should be made towards registration procedures that stimulate the development of the mycorrhizal industry. Some on-farm inoculum production and application methods have been studied, allowing farmers to produce locally adapted isolates and generate a taxonomically diverse inoculum (Mohandas et al, 2004; Douds et al, 2005). However the inocula produced this way are not readily processed for mechanical application to the fields, being an obstacle to the utilization in large scale agriculture, especially row crops, moreover it would represent an additional mechanical operation with the corresponding economic and soil compaction costs. It is well recognized that inoculation of AM fungi has a potential significance in not only sustainable crop production, but also environmental conservation. However, the status quo of inoculation is far from practical technology that can be widely used in the field. Together a further basic understanding of the biology and diversity of AM fungi is needed (Abbott at al, 1995; Saito and Marumoto, 2002). Advances in ecology during the past decade have led to a much more detailed understanding of the potential negative consequences of species introductions and the potential for negative ecological consequences of invasions by mycorrhizal fungi is poorly understood. Schwartz et al, (2006) recommend that a careful assessment documenting the need for inoculation, and the likelihood of success, should be conducted prior to inoculation because inoculations are not universally beneficial. Agricultural practices such as crop rotation, tillage, weed control and fertilizer apllication all produce changes in the chemical, physical and biological soil variables and affect the ecological niches available for occupancy by the soil biota, influencing in different ways the symbiosis performance and consequently the inoculum development, shaping changes and upset balance of native populations. The molecular biology tools developed in the latest years have been very important for our perception of these changes, ensuing awareness of management choice implications in AM development. In this context, for extensive farming systems and regarding environmental and economic costs, the identification of agronomic management practices that allow controlled manipulation of the fungal community and capitalization of AM mutualistic effect making use of local inoculum, seem to be a wise option for mycorrhiza promotion and development of sustainable crop production