554 research outputs found
Ethanol triggers grape gene expression leading to anthocyanin accumulation during berry ripening
Recent studies have shown that low doses of ethanol stimulate the maturation of some fruits. The present work showed that
spraying Cabernet Sauvignon grapes, with 5% ethanol at veraison enhances the anthocyanin accumulation. Veraison is the time
when the berries turn from green to purple. HPLC analysis showed a marked increase in the total concentrations of the derivatives
of delphinidin, cyanidin, petunidin, peonidin and malvidin from the fourth day after the ethanol treatment until harvest. This was
not linked to a difference in berry weight in comparison to controls. Two distinct expression patterns were found for anthocyanin
biosynthesis genes in the treated and untreated berries. For one group, consisting of chalcone synthase, flavanone-3-hydroxylase,
dihydroxyflavonol-4-reductase and leucoanthocyanidin dioxygenase, the expression was inhibited or unchanged by the ethanol
treatment, whereas for UDP glucose-flavonoid 3-O-glucosyltransferase (UFGT) there was a marked increase in expression from 1
to 20 days after ethanol treatment. These results suggest that the UFGT gene is a key factor in the observed anthocyanin
accumulation following ethanol treatment
Sleep problems are associated with poor outcomes in remedial teaching programmes: A preliminary study
Problematic behaviour and deficient academic performance have been reported in children with sleep problems, but whether sleep problems are common among children presenting with primary behavioural and performance concerns in remedial programmes is not well studied. We studied this possibility in 80 Australian school children aged 6–15 years and then compared 15 of these children from mainstream schools to 15 demographically matched children in specialist behavioural programmes for problematic behaviour and academic difficulties. Methods: Parents completed the Child Behaviour Checklist and the Sleep Disorders Scale for Children. Questionnaires assessed behaviour, academic performance and symptoms of diverse sleep disorders, expressed as T-scores (mean (SD) = 50 (10)). Teachers rated students' academic performance (A, B, C, D, E). Results: When compared with the 15 controls, the 15 index children had significantly more sleep problems, in addition to parental concerns about school performance. In the total sample ( n = 80), poor sleep including symptoms of daytime sleepiness, parasomnias, behavioural sleep problems and combined sleep problems was associated with poor academic performance and daytime behavioural issues. Conclusions: This preliminary study suggests that children in remedial school programmes may have poor sleep compared with those in mainstream schools. Sleep problems were associated with problematic behaviour and poor academic performance. If sleep disturbances worsen daytime behaviour, then diagnosis and treatment of underlying sleep disorders could offer a novel therapeutic opportunity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72509/1/j.1440-1754.2007.01237.x.pd
Changes in Grape Maturity Induced by Spraying Ethanol
Three different ethanol solutions were sprayed onto Cabernet Sauvignon (Vitis vinifera L.) clusters during the ripening period: 2.5, 5 and 10% by volume in water. Controls were sprayed with water alone. Three different times of spraying were also tested: 8, 10 and 13 weeks post-flowering. One of the observed changes was a lower titratable acidity in grape samples at harvest, when the clusters were sprayed with ethanol at 10 weeks, in comparison with controls. The wines made with grapes treated with ethanol after mid-veraison, had higher ODs at 520 nm than did the controls. This may due to a combined effect of red pigment levels and acidity. In addition, following malolactic fermentation, the acidity levels of wines made with ethanoltreated grapes were slightly higher than those made with the control grapes. Spraying ethanol at 13 weeks post-flowering increased the berry weight by 10% at harvest without decreasing the °Brix value. The corresponding wines had similar degrees of alcohol. This observation was made for the first time in 2001
Disk Heating, Galactoseismology, and the Formation of Stellar Halos
Deep photometric surveys of the Milky Way have revealed diffuse structures
encircling our Galaxy far beyond the "classical" limits of the stellar disk.
This paper reviews results from our own and other observational programs, which
together suggest that, despite their extreme positions, the stars in these
structures were formed in our Galactic disk. Mounting evidence from recent
observations and simulations implies kinematic connections between several of
these distinct structures. This suggests the existence of collective disk
oscillations that can plausibly be traced all the way to asymmetries seen in
the stellar velocity distribution around the Sun. There are multiple
interesting implications of these findings: they promise new perspectives on
the process of disk heating, they provide direct evidence for a stellar halo
formation mechanism in addition to the accretion and disruption of satellite
galaxies, and, they motivate searches of current and near-future surveys to
trace these oscillations across the Galaxy. Such maps could be used as
dynamical diagnostics in the emerging field of "Galactoseismology", which
promises to model the history of interactions between the Milky Way and its
entourage of satellites, as well examine the density of our dark matter halo.
As sensitivity to very low surface brightness features around external galaxies
increases, many more examples of such disk oscillations will likely be
identified. Statistical samples of such features not only encode detailed
information about interaction rates and mergers, but also about long
sought-after dark matter halo densities and shapes. Models for the Milky Way's
own Galactoseismic history will therefore serve as a critical foundation for
studying the weak dynamical interactions of galaxies across the universe.Comment: 20 pages, 5 figures, accepted in for publication in a special edition
of the journal "Galaxies", reporting the proceedings of the conference "On
the Origin (and Evolution) of Baryonic Galaxy Halos", Puerto Ayora, Ecuador,
March 13-17 2017, Eds. Duncan A. Forbes and Ericson D. Lope
Complex high-pressure polymorphism of barium tungstate
We have studied BaWO 4 under compression at room temperature by means of x-ray diffraction and Raman spectroscopy. When compressed with neon as a pressure-transmitting medium (quasihydrostatic conditions), we found that BaWO 4 transforms from its low-pressure tetragonal structure into a much denser monoclinic structure. This result confirms our previous theoretical prediction based on ab initio calculations that the scheelite to BaWO 4-II transition occurs at room temperature if kinetic barriers are suppressed by pressure. However, our experiment without any pressure- transmitting medium has resulted in a phase transition to a completely different structure, suggesting nonhydrostaticity may be responsible for previously reported rich polymorphism in BaWO 4. The crystal structure of the low- and high-pressure phases from the quasihydrostatic experiments has been Rietveld refined. Additionally, for the tetragonal phase the effects of pressure on the unit-cell volume and lattice parameters are discussed. Finally, the pressure evolution of the Raman modes of different phases is reported and compared with previous studies. © 2012 American Physical Society.This research was supported by Spanish MEC (Grant No. MAT2010-21270-C04-01/04), MALTA Consolider Ingenio 2010 (Grant No. CSD2007-00045), and Vicerrectorado de Investigacion y Desarrollo of the Universitat Politecnica de Valencia (Grants No. UPV2011-0914 PAID-05-11 and No. UPV2011-0966 PAID-06-11). XRD data were collected at HPCAT, Advanced Photon Source (APS), Argonne National Laboratory. HPCAT is supported by CIW, CDAC, UNLV, and LLNL through funding from DOE-NNSA, DOE-BES, and NSF. APS is supported by DOE-BES under Contract No. DEAC02-06CH11357.Gomis Hilario, O.; Sans, JA.; Lacomba-Perales, R.; Errandonea, D.; Meng, Y.; Chervin, JC.; Polian, A. (2012). Complex high-pressure polymorphism of barium tungstate. 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High-pressure x-ray and neutron powder diffraction study of PbWO4and BaWO4scheelites. Journal of Physics: Condensed Matter, 18(11), 3017-3029. doi:10.1088/0953-8984/18/11/008Errandonea, D., Pellicer-Porres, J., Manjón, F. J., Segura, A., Ferrer-Roca, C., Kumar, R. S., … Aquilanti, G. (2006). Determination of the high-pressure crystal structure ofBaWO4andPbWO4. Physical Review B, 73(22). doi:10.1103/physrevb.73.224103Panchal, V., Garg, N., Chauhan, A. K., Sangeeta, & Sharma, S. M. (2004). High pressure phase transitions in BaWO4. Solid State Communications, 130(3-4), 203-208. doi:10.1016/j.ssc.2004.01.043Jayaraman, A., Batlogg, B., & VanUitert, L. G. (1983). High-pressure Raman study of alkaline-earth tungstates and a new pressure-induced phase transition in BaWO4. Physical Review B, 28(8), 4774-4777. doi:10.1103/physrevb.28.4774Kawada, I., Kato, K., & Fujita, T. (1974). BaWO4-II (a high-pressure form). 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POWDER CELL – a program for the representation and manipulation of crystal structures and calculation of the resulting X-ray powder patterns. Journal of Applied Crystallography, 29(3), 301-303. doi:10.1107/s0021889895014920Birch, F. (1978). Finite strain isotherm and velocities for single-crystal and polycrystalline NaCl at high pressures and 300°K. Journal of Geophysical Research, 83(B3), 1257. doi:10.1029/jb083ib03p01257Liu, H., Ding, Y., Somayazulu, M., Qian, J., Shu, J., Häusermann, D., & Mao, H. (2005). Rietveld refinement study of the pressure dependence of the internal structural parameteruin the wurtzite phase of ZnO. Physical Review B, 71(21). doi:10.1103/physrevb.71.212103Liu, H., Hu, J., Shu, J., Häusermann, D., & Mao, H. (2004). Lack of the critical pressure for weakening of size-induced stiffness in 3C–SiC nanocrystals under hydrostatic compression. 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Pulse propagation in discrete excitatory networks of integrate-and-fire neurons
We study the propagation of solitary waves in a discrete excitatory network of integrate-and-fire neurons. We show the existence and the stability of a fast wave and a family of slow waves. Fast waves are similar to those already described in continuum networks. Stable slow waves have not been previously reported in purely excitatory networks and their propagation is particular to the discrete nature of the network. The robustness of our results is studied in the presence of noise
Determination of the aldosterone/plasma renin activity ratio for the screening of primary hyperaldosteronism in essential hypertension: a multicentric study
El hiperaldosteronismo primario (HAP) es una afección caracterizada por la producción inapropiadamente elevada y una relativa autonomía del sistema renina-angiotensina. Estimaciones previas, basadas sólo en la evaluación de hipertensos con hipokalemia, consideraban al HAP como una causa poco frecuente de hipertensión (1%). Sin embargo, estudios actuales fundamentados en el cálculo de la relación aldosterona/ actividad de renina plasmática (RAA) arrojan una incidencia mayor (5-10%), siendo la hipertensión arterial (HTA) normokalémica la presentación más frecuente. Dada la amplitud de los valores de corte de la RAA, el Departamento de Suprarrenal de SAEM diseñó un estudio multicéntrico prospectivo en una población de Argentina con el objetivo de establecer nuestro propio valor y determinar así la prevalencia de HAP. Fueron estudiados 353 individuos de ambos sexos, 104 controles normotensos, sin antecedentes familiares de HTA y 249 pacientes hipertensos. Se indicó dieta normosódica y la suspensión de antihipertensivos que interfieran con el eje mineralocorticoideo. Las determinaciones de la actividad de renina plasmática (ARP), DIA-SorinRIA, y de aldosterona, RIA-DPC, fueron realizadas en un único laboratorio. Se realizó ionograma y se evaluaron parámetros clínicos y bioquímicos de síndrome metabólico. La RAA calculada según el percentilo 95 en los controles, fue establecida en la cifra de 36 como valor de corte para sospechar HAP en los hipertensos, requiriéndose una concentración de aldosterona >15 ng/ml. Con una RAA≥36, se realizaron pruebas confirmatorias de sobrecarga salina o de fludrocortisona. La RAA fue ≥36 en 31/249 pacientes, confirmándose HAP en 8 (7 adenomas y 1 hiperplasia), con una prevalencia del 3.2%. Los restantes no completaron estudios confirmatorios. La presencia de síndrome metabólico fue similar en los hipertensos con y sin HAP. En conclusión, este primer estudio multicéntrico argentino determinó nuestro valor de corte de la RAA en 36. Su aplicación permitió establecer una prevalencia de HAP del 3,2% que, aunque podría estar subestimada, resulta significativamente mayor que la previa histórica y concuerda con la incidencia referida en la bibliografía.Primary hyperaldosteronism (PHA) or Conn's disease was classically suspected in the presence of hypertension (H) and hypokalemia. It was previously considered as a rare cause of H, being reported in only 1% of hypertensive patients. It can be caused by an adrenal adenoma (the former usual presentation) or by adrenal hyperplasia. But since the use of the aldosterone/plasma renin activity ratio (AAR) as the screening method in the last years, it is currently considered as almost the most frequent cause of secondary H., accounting for 5-10% of essential H. Plasma rennin activity (PRA) determination is a laborious procedure with low reproducibility and it directly affects the AAR; thus each laboratory must assess its own cut-off value. Therefore, in the Adrenal Department of the Argentine Society of Endocrinology and Metabolism (SAEM), we performed this multicentric prospective study of a population of Argentina with the aim of assessing our own AAR cut-off level in normotensive controls in order to apply it for PHA screening in essential hypertensive patients. We studied 353 adult subjects: 104 controls, aged 45,18 ± 13,78 years-old ( X±SD), with no history of arterial hypertension in their first-degree relatives and with two separate day-registry of blood pressure≤ 139/85 mmHg and 249 hypertensive patients, aged 51± 13,6 years-old ( X ± SD), with arterial blood pressure≥ 140/90 mmHg in the sitting position. Subjects with cardiac, renal, hepatic and neurological diseases were excluded as well as those with Cushing´s syndrome, hyperthyroidism, untreated hypothyroidism, diabetes mellitus and patients under glucocorticoids, oral contraceptive pills or estrogen therapy. A normal sodium diet was indicated and potassium was supplemented when needed. Blood was withdrawn between 8 and 10:00 a.m. with the subjects in the upright position. Aldosterone (A) was determined by DPC radioimmunoassay (RIA) and PRA, by DIA-Sorin RIA. The A normal levels are 4-30 ng/dl for ambulatory individuals on a normal sodium diet and the PRA normal values are < 3,3 ng/ml/h. In order to avoid false positive results in the hypertensive group, AAR was calculated when A was above 15 ng/dl. We measured the waist circumference and we determined the body mass index. Blood sodium, potassium, calcium, urea, creatinine, cholesterol, HDL-C, LDL-C, triglyceride and liver function tests were performed. Statistical Analysis and Results Since the AAR variable showed a non-normal distribution, the cut-off value was considered as the 95th percentile in the control group, which was calculated as 36. This is also in accordance to the function of the empirical distribution of Collings and Hamilton. In our 249 hypertensive patients, 31 had an AAR ≥ 36. PHA was confirmed in 8: seven has an adrenal adenoma and one had hyperplasia. The prevalence of PHA in our population was 3,2 %, with a 95th confidence interval ranging from 1,4 to 6,2 %. In the remaining 23 patients, confirmatory tests could not be completed. There was no correlation between the severity of the hypertension and the AAR value, with no statistical significant differences between those with or without PHA. Likewise, we found no correlation between PRA and advancing age. In hypertensive patients, metabolic syndrome was more prevalent than in controls, but it was present to the same extent in those with or without PHA. Conclusions To our knowledge, this is the first multicentric study performed in Argentina to determine the aldosterone/ plasma renin activity ratio in our normotensive control population. Our AAR value of 36 agrees with the levels reported in the international literature: thus an AAR ≥ 36 along with an aldosterone ≥ 15 ng/ml in hypertensive patients lead us to suspect PHA and to perform confirmatory tests. Applying these criteria, we found a prevalence of 3,2% of PHA in essential HTA. It is possible that this value may be underestimated due to the fact that confirmatory tests could not be completed in all the hypertensive subjects with an AAR≥ 36. In spite of this, our prevalence is significantly greater than the historical one and it lies in the range reported in the literature.Fil: Pardes, E.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Belli, S.. Hospital Dr. C. Durand; ArgentinaFil: Cornaló, D.. Hospital Rivadavia; ArgentinaFil: Contreras, Liliana Noemi. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones Medicas; ArgentinaFil: Costa, L.. Hospital Dr. A. Posadas; ArgentinaFil: Chervin. R.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Damilano, S.. Laboratorio de Bioanalítica; ArgentinaFil: Fenili, C.. Laboratorio de Bioanalítica; ArgentinaFil: Gómez, R. M.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Leal Reyna, M.. Complejo Médico Policial "Churruca"; ArgentinaFil: Lupi, S.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Martínez, M.. Hospital Francés; ArgentinaFil: Nofal, M.. Clínica Bazterrica; ArgentinaFil: Ruibal, G.. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Dr. Teodoro Álvarez"; Argentin
Minimizing Shape Change at Zn Sponge Anodes in Rechargeable Ni-Zn Cells: Impact of Electrolyte Formulation
The historically poor electrochemical rechargeability of Zn in alkaline electrolyte has hindered the commercial viability of Ni-Zn batteries, a system otherwise of interest because of high specific energy (up to 140 Wh kg -1 ). We have redesigned the Zn anode as a three-dimensional (3D), monolithic porous architecture ("sponge") that exhibits unprecedented Zn specific capacity and dendrite-free cycling. Maintaining the integrity of the 3D Zn sponge architecture throughout charge-discharge is required to ultimately achieve technologically relevant performance in terms of cycle life and capacity. En route to this goal, we systematically evaluated a series of electrolyte and electrode additives used in conjunction with our Zn sponge anode in order to down-select formulations that minimize electrode shape change with cycling in prototype Ni-3D Zn cells. The classes of additives chosen for this study include those that either inhibit ZnO passivation during discharge (Type I: LiOH, K 2 SiO 3 ) or promote it (Type II/III: KF, K 2 CO 3 , ZnO, Ca(OH) 2 ), as well as combinations thereof. We find that the second class of additives effectively retains the cycled Zn sponge in its pre-cycled condition. Nickel-zinc (Ni-Zn) batteries exhibit high practical specific energies (up to 140 Wh kg -1 ) and operate using earth-abundant active materials and nonflammable aqueous electrolytes. The Zn electrode has a high theoretical specific capacity (820 mAh g -1 ) and depending on the target depth-of-discharge at the Zn (DOD Zn ), Ni-Zn batteries are an attractive competitor to Pb-acid, Ni-metal hydride, and Li-ion batteries. Despite these advantages, the historically poor rechargeability of the Zn electrode has hindered the Ni-Zn system from contending in the consumer marketplace. While examples of commercial secondary Ni-Zn batteries exist (e.g., Battery Power International (BPI) and PowerGenix), they remain plagued by limited cycle life and inconsistency in meeting manufacturer-specified capacity. 1 Until recently, the prevailing method to enhance the cycle life of Zn-based batteries (Ni-Zn, Ag-Zn, Zn-MnO 2 ) focused on the use of additives in the electrolyte and/or incorporated into the electrode structure to mitigate the formation of short-inducing dendrites at the Zn anode. This approach has been modestly successful, 2,3,4,5 yet the lack of a competitive commercial Ni-Zn battery with long cycle life suggests that further advances beyond reliance on additives is required. In response to this challenge, we have redesigned the Zn anode as a three-dimensional (3D), monolithic, aperiodic porous Zn architecture ("sponge"). Additives for Zn-based batteries can be classified into three distinct types: r "Type I" electrolyte additives that prevent ZnO passivation of the electrode by suppressing supersaturation of zincate anions (Z
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