289 research outputs found

    Genotypic variation in phosphorus efficiency between wheat cultivars grown under greenhouse and field conditions

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    Phosphorus (P) efficiency (relative growth), which is described as the ratio of shoot dry matter or grain yield at deficient P supply to that obtained under adequate P supply, was compared in 25 winter wheat cultivars grown under greenhouse and field conditions with low and adequate P levels in a P-deficient calcareous soil. Adequate P supply resulted in significant increases in shoot dry weight and grain yield under both experimental conditions. In the greenhouse experiment, the increases in shoot dry weight under adequate P supply (80 mg kg(-1)) were from 0% (cv: C-1252) to 34% (cv: Dagdas). Under field conditions, the cultivars showed much greater variation in their response to adequate P supply (60 kg ha(-1)): the increases in shoot dry weight and grain yield with adequate P supply were between -2% (cv: Sivas-111/33) and 25% (cv: Kirac-66) for shoot dry matter production at the heading stage and between 0% (cv: Kirkpinar-79) and 76% (cv: Kate A-1) for grain yield at maturity. Almost all cultivars behaved totally different in their response to P deficiency under greenhouse and field conditions. Phosphorus efficiency ratios (relative growth) under greenhouse conditions did not correlate with the P efficiency ratios under field conditions. In general, durum wheat cultivars were found to be more P efficient compared with bread wheat cultivars. The results of this study indicated that there is wide variation in tolerance to P deficiency among wheat cultivars that can be exploited in breeding new wheat cultivars for high P deficiency tolerance. The results also demonstrated that P efficiency was expressed differently among the wheat cultivars when grown under greenhouse and field conditions and, therefore, special attention should be paid to growth conditions in screening wheat for P efficiency

    Total Mass and Charge Distributions in the p + 27-Al Reaction at 180 MeV

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    This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit

    A Global Study of the p+27-Al Reaction at 180 MeV

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    This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit

    Joinability of Particulate Reinforced Alumix 231 Based Composite Materials Produced by Powder Metallurgy Route

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    In the present study, weldability of Alumix 231 based composite materials reinforced with Al₂O₃ and B₄C and produced by powder metallurgy route is investigated. Various amounts of (0, 5, 10, and 15% wt.)Al₂O₃ and B₄C powders are added to the pre-alloyed Alumix 231 (Al—2.5% Cu—0.5% Mg—14% Si) powders separately and then mixed in a three-dimensional mixer for 45 min. Powders are compacted and sintered in an argon atmosphere at 640°C for 4 h. Produced blocks are welded by the Tungsten Inert Gas (TIG) welding at 25 V, 197 A and 14 l/min shielded gas flow in commercially pure argon atmosphere. Macro- and microexamination together with some mechanical properties of the welded area are studied. The results show that, although high amount of particles resulted in a decrease in the density, these composite materials can still be welded by the TIG welding method successfully.Исследуется свариваемость произведённых методом порошковой металлургии композитных материалов на основе Alumix 231, армированных Al₂O₃ и B₄C. Различные количества (0, 5, 10 и 15 масс.%) порошков Al₂O₃ и B₄C по отдельности добавлялись в предварительно сплавленные порошки Alumix 231 (Al—2,5% Cu—0,5% Mg—14% Si), а затем перемешивались в трёхмерном миксере в течение 45 минут. Затем порошки прессовались и спекались в атмосфере аргона при 640°C в течение 4 часов. Полученные блоки сваривались вольфрамовой сваркой в атмосфере инертного газа при 25 В, 197 А и потоке инертного газа в 14 л/мин в атмосфере технически чистого аргона. Были проведены макро- и микроисследования некоторых механических свойств сварной зоны. Их результаты показали, что, хотя оказалось большое количество частиц с пониженной плотностью, эти композитные материалы могут быть успешно сварены методом вольфрамовой сварки в атмосфере инертного газа.Досліджується зварюваність вироблених методою порошкової металургії композитних матеріялів на основі Alumix 231, армованих Al₂O₃ і B₄C. Різні кількості (0, 5, 10 і 15 мас.% ) порошків Al₂O₃ і B₄C окремо додавалися у попередньо стоплені порошки Alumix 231 (Al—2,5% Cu—0,5% Mg—14% Si), а потім перемішувалися в тривимірному міксері впродовж 45 хвилин. Потім порошки пресувалися та спікалися в атмосфері арґону при 640°C впродовж 4 годин. Одержані блоки зварювалися вольфрамовим зваренням в атмосфері інертного газу при 25 В, 197 А та потоці інертного газу у 14 л/хв. в атмосфері технічно чистого арґону. Було виконано макро- та мікродослідження деяких механічних властивостей зварної зони. їх результати показали, що, хоча виявилася велика кількість частинок зі зниженою густиною, ці композитні матеріяли можуть бути успішно зварені методою вольфрамового зварювання в атмосфері інертного газу

    Screening of suitable cationic dopants for solar absorber material CZTS/Se: A first principles study

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    The earth abundant and non-toxic solar absorber material kesterite Cu2ZnSn(S/Se)(4) has been studied to achieve high power conversion efficiency beyond various limitations, such as secondary phases, antisite defects, band gap adjustment and microstructure. To alleviate these hurdles, we employed screening based approach to find suitable cationic dopant that can promote the current density and the theoretical maximum upper limit of the energy conversion efficiency (P(%)) of CZTS/Se solar devices. For this task, the hybrid functional (Heyd, Scuseria and Ernzerhof, HSE06) were used to study the electronic and optical properties of cation (Al, Sb, Ga, Ba) doped CZTS/Se. Our in-depth investigation reveals that the Sb atom is suitable dopant of CZTS/CZTSe and also it has comparable bulk modulus as of pure material. The optical absorption coefficient of Sb doped CZTS/Se is considerably larger than the pure materials because of easy formation of visible range exciton due to the presence of defect state below the Fermi level, which leads to an increase in the current density and P(%). Our results demonstrate that the lower formation energy, preferable energy gap and excellent optical absorption of the Sb doped CZTS/Se make it potential component for relatively high efficient solar cells

    CCD UBV photometric and Gaia astrometric study of eight open clusters- ASCC 115, Collinder 421, NGC 6793, NGC 7031, NGC 7039, NGC 7086, Roslund 1 and Stock 21

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    In this study, we carried out CCD UBV photometry of eight open clusters, ASCC 115, Collinder 421, NGC 6793, NGC 7031, NGC 7039, NGC 7086, Roslund 1, Stock 21, and determined their reddening, metallicity, distance, age, and mass functions. We used new Gaia Data Release 2 (DR2) astrometric data to separate cluster member stars from the field stars and obtain precise structural and astrophysical parameters. To identify cluster member stars we utilized an unsupervised membership assignment code (UPMASK), which is based on the photometric and astrometric data. The density distributions for the open clusters show good fits with the empirical King model except for Roslund 1 and Stock 21 not having central concentration. The colour excesses and metallicities were derived separately using U-B vs B-V two-colour diagrams. Keeping these parameters as constants, we simultaneously calculated distance moduli and ages of the clusters from V vs B-V and V vs U-B colour-magnitude diagrams using PARSEC theoretical isochrones. Taking into account Gaia DR2 proper motion components and parallaxes of the member stars, we also calculated mean proper motions and distances for the clusters. Distances derived both from isochrone fitting to colour-magnitude diagrams of the clusters and Gaia DR2 trigonometric parallaxes are compatible with each other. Slopes of the mass functions of the eight open clusters are in good agreement with Salpeter (1955) value of 1.35.Comment: 24 pages, 12 figures and 7 tables, accepted for publication in Astrophysics and Space Scienc

    Brain function assessment in different conscious states

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    Background: The study of brain functioning is a major challenge in neuroscience fields as human brain has a dynamic and ever changing information processing. Case is worsened with conditions where brain undergoes major changes in so-called different conscious states. Even though the exact definition of consciousness is a hard one, there are certain conditions where the descriptions have reached a consensus. The sleep and the anesthesia are different conditions which are separable from each other and also from wakefulness. The aim of our group has been to tackle the issue of brain functioning with setting up similar research conditions for these three conscious states.Methods: In order to achieve this goal we have designed an auditory stimulation battery with changing conditions to be recorded during a 40 channel EEG polygraph (Nuamps) session. The stimuli (modified mismatch, auditory evoked etc.) have been administered both in the operation room and the sleep lab via Embedded Interactive Stimulus Unit which was developed in our lab. The overall study has provided some results for three domains of consciousness. In order to be able to monitor the changes we have incorporated Bispectral Index Monitoring to both sleep and anesthesia conditions.Results: The first stage results have provided a basic understanding in these altered states such that auditory stimuli have been successfully processed in both light and deep sleep stages. The anesthesia provides a sudden change in brain responsiveness; therefore a dosage dependent anesthetic administration has proved to be useful. The auditory processing was exemplified targeting N1 wave, with a thorough analysis from spectrogram to sLORETA. The frequency components were observed to be shifting throughout the stages. The propofol administration and the deeper sleep stages both resulted in the decreasing of N1 component. The sLORETA revealed similar activity at BA7 in sleep (BIS 70) and target propofol concentration of 1.2 μg/mL.Conclusions: The current study utilized similar stimulation and recording system and incorporated BIS dependent values to validate a common approach to sleep and anesthesia. Accordingly the brain has a complex behavior pattern, dynamically changing its responsiveness in accordance with stimulations and states. © 2010 Ozgoren et al; licensee BioMed Central Ltd

    Polypeptide-grafted macroporous polyHIPE by surface-initiated N-Carboxyanhydride (NCA) polymerization as a platform for bioconjugation

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    A new class of functional macroporous monoliths from polymerized high internal phase emulsion (polyHIPE) with tunable surface functional groups was developed by direct polypeptide surface grafting. In the first step, amino-functional polyHIPEs were obtained by the addition of 4-vinylbenzyl or 4-vinylbenzylphthalimide to the styrenic emulsion and thermal radical polymerization. The obtained monoliths present the expected open-cell morphology and a high surface area. The incorporated amino group was successfully utilized to initiate the ring-opening polymer- ization of benzyl-L-glutamate N-carboxyanhydride (BLG NCA) and benzyloxycarbonyl-L-lysine (Lys(Z)) NCA, which resulted in a dense homogeneous coating of polypeptides throughout the internal polyHIPE surfaces as confirmed by SEM and FTIR analysis. The amount of polypeptide grafted to the polyHIPE surfaces could be modulated by varying the initial ratio of amino acid NCA to amino-functional polyHIPE. Subsequent removal of the polypeptide protecting groups yielded highly functional polyHIPE-g-poly(glutamic acid) and polyHIPE-g- poly(lysine). Both types of polypeptide-grafted monoliths responded to pH by changes in their hydrohilicity. The possibility to use the high density of function (−COOH or −NH2) for secondary reaction was demonstrated by the successful bioconjugation of enhanced green fluorescent protein (eGFP) and fluorescein isocyanate (FITC) on the polymer 3D-scaffold surface. The amount of eGFP and FITC conjugated to the polypeptide-grafted polyHIPE was significantly higher than to the amino- functional polyHIPE, signifying the advantage of polypeptide grafting to achieve highly functional polyHIPEs
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