Determination of mineral element concentrations in wheat,sunflower, chickpea and lentil cultivars in response to P fertilization by polarized energy dispersive X‐ray fluorescence

Concentrations of elements (P, K, S, Ca, Mg, Si, Cl, Fe, Zn, Cu, Mn, Mo, Na, Al, Ti, Ni, Ba, As, Br, Rb and Sr) of wheat, sunflower, chickpea and lentil cultivars grown in low and high phosphorus soil were investigated by polarized energy dispersive X‐ray fluorescence (PEDXRF). The phosphorus treatment x cultivars interaction was significant for the growth and element concentrations, and cultivars within plant species differed considerably with respect to element concentrations as the result of P fertilization. Shoot growth of the cultivars of each plant species was increased in response to phosphorus fertilization. Application of P increased the P concentrations of wheat, sunflower, chickpea and lentil cultivars. Under high P conditions, mean K concentrations of wheat and sunflower cultivars were decreased while the mean K concentrations of chickpea and lentil were increased. With the exception of sunflower cultivars, applied P significantly increased S concentration of the cultivars of wheat, chickpea and lentil. Calcium concentrations of wheat and sunflower cultivars were reduced by P fertilization and that of chickpea and lentil were increased. Applied P decreased mean Mg concentrations in sunflower, increased in chickpea and lentil cultivars and showed no effects on the wheat cultivars. Applied P significantly decreased mean Si concentrations of wheat and sunflower while mean Si concentrations of the chickpea and lentil cultivars were increased. Chloride concentrations of the wheat and sunflower cultivars were decreased and those of the chickpea and lentil cultivars were increased by applied P. In general, Fe concentrations of the wheat and chickpea cultivars were significantly increased by applied P. Zinc and Cu concentrations of all the cultivars of the four plant species were reduced by P, particularly Zn concentrations. However, applied P increased mean Mn concentrations of wheat and chickpea and decreased those of chickpea cultivars. Mean Mo concentrations of wheat and chickpea increased but decreased in sunflower and lentil cultivars. In general, applied P increased mean Na concentration of wheat and decreased that of chickpea and lentil. Aluminum concentrations of wheat and chickpea cultivars were decreased by applied P. Applied P decreased Ti concentrations of wheat and sunflower cultivars and increased Ti concentrations of chickpea and lentil. Nickel concentrations of wheat and chickpea were increased and those of sunflower and lentil were decreased by applied P. Applied P reduced the Ba and increased As and Rb concentrations of all the cultivars within the plant species. Bromine concentrations of wheat and lentil were decreased and those of sunflower and chickpea were increased by applied P. Finally, Sr concentrations in wheat and sunflower cultivars were reduced, and increased in chickpea cultivars with applied P. Copyright © 2009 John Wiley & Sons, Ltd.     

A comparative photoluminescence study on Mn-Free GaAs/AlAs and Mn-containing Ga1-xMnxAs/AlAs quantum wells (QWs) grown on various orientations by MBE

Optical properties of diluted magnetic semiconductor Ga_0.999Mn_0.001As/AlAs quantum well structures grown on (1?0?0?), (1?1?0), (3?1?1)B and (4?1?1)B by molecular beam epitaxy are reported. Temperature-dependent spectral photoluminescence (PL) measurement was performed at temperatures between 15 and 300 K. The PL measurements showed that band gap of the alloy decreases with increasing lattice temperature regardless the growth orientations. S-shaped temperature dependence has been observed in the samples grown on (1?0?0), (3?1?1)B, (4?1?1)B orientations. PL emission energy is fitted with Varshni and Bose–Einstein Approximation to determine Debye temperature (β), (Θ_E) and thermal expansion coefficient (α), the exciton–phonon coupling strength (a_B).     

Effect of thermal expansion on shape memory behavior of polyurethane and its nanocomposites

The effects of thermal expansion on shape memory performance of shape memory polyurethanes and their nanocomposites with organoclay, carbon nanofiber (CNF), silicon carbide (SiC), and carbon black (CB) were evaluated. The shape memory test cycle involved tensile deformation at above the trigger temperature to initiate shape memory function, cooling to room temperature to fix the shape, and shape recovery induced by heating to above the trigger temperature. Phenomenological models were used to interpret the experimental data on coefficient of thermal expansion (CTE). It was found that Kerner model showed good fit for composites of SiC and CB, and Halpin model gave better fit for composites of organoclay and CNF. It was observed that thermal expansion exerts negative effect on recovered strain, the extent of which depends on the magnitude of temperature gradient, CTE, and the level of tensile strain. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1437–1449, 2008     

Heat transfer enhancement in a tube with equilateral triangle cross sectioned coiled wire inserts

The heat transfer and pressure drop were experimentally investigated in a coiled wire inserted tube in turbulent flow regime. The coiled wire has equilateral triangular cross section and was inserted separately from the tube wall. The experiments were carried out with three different pitch ratios (P/D = 1, 2 and 3) and two different ratio of equilateral triangle length side to tube diameter (a/D = 0.0714 and 0.0892) at a distance (s) of 1 mm from the tube wall in the range of Reynolds number from 3500 to 27,000. Uniform heat flux was applied to the external surface of the tube and air was selected as fluid. The experimental results obtained from a smooth tube were compared with those from the studies in literature for validation of experimental set-up. The use of coiled wire inserts leads to a considerable increase in heat transfer and pressure drop over the smooth tube. The Nusselt number rises with the increase of Reynolds number and wire thickness and the decrease of pitch ratio. The highest overall enhancement efficiency of 36.5% is achieved for the wire with a/D = 0.0892 and P/D = 1 at Reynolds number of 3858. Consequently, the experimental results reveal that the best operating regime of all coiled wire inserts is detected at low Reynolds number, leading to more compact heat exchanger.     

Quantum lifetimes and momentum relaxation of electrons and holes in Ga0.7In0.3N0.015As0.985/GaAs quantum wells

Electronic transport in n- and p-type modulation-doped Ga_0.7In_0.3N_0.015As_0.985/GaAs quantum wells are investigated using magneto-transport measurements in the temperature range between T?=?1.8 and 32?K and at magnetic fields up to B?=?11?T. The momentum relaxation and the quantum lifetimes (τ_q ) of electrons and holes are obtained directly from the temperature and magnetic field dependencies of the SdH oscillation amplitudes, respectively. A detailed analysis of quantum and transport life times indicates that the momentum relaxation of holes is forward displaced in k-space, while a large angle-scattering mechanism is prominent for the electrons. This discrepancy is believed to be due to scattering of electrons with nitrogen complexes and to the lack of such a mechanism for holes.     

Resonant ultrasound spectroscopy and homogeneity in polycrystals

Resonant ultrasound spectroscopy (RUS) is capable of determining the bulk elastic properties of a solid from its characteristic vibration frequencies, given the dimensions, density and shape of the sample. The model used for extracting values of the elastic constants assumes perfect homogeneity, which can be approximated by average-isotropic polycrystals. This approximation is excellent in the small grain regime assumed for most averaging procedures, but for real samples with indeterminate grain size distributions, it is not clear where the approximation breaks down. RUS measurements were made on pure copper samples where the grain size distribution was changed by progressive heat treatments in order to find a quantitative limit for the loss of homogeneity. It is found that when a measure of the largest grains is 15% of the sample’s smallest dimension, the deviation in RUS fits indicates elastic inhomogeneity.     

Anti-Inflammatory and Neuromodulatory Effects Induced by Tanacetum parthenium Water Extract: Results from In Silico,In Vitro and Ex Vivo Studies

Tanacetum parthenium (feverfew) has traditionally been employed as a phytotherapeutic remedy in the treatment of migraine. In this study, a commercial T. parthenium water extract was investigated to explore its anti-inflammatory and neuromodulatory effects. Isolated mouse cortexes were exposed to a K⁺ 60 mM Krebs-Ringer buffer and treated with T. parthenium water extract. The prostaglandin E₂ (PGE₂) level, brain-derived neurotrophic factor (BDNF), interleukin-10 (IL-10), and IL-1β gene expression were evaluated in the cortex. The effects on dopamine (DA) release and dopamine transporter (DAT) gene expression were assayed in hypothalamic HypoE22 cells. A bioinformatics analysis was conducted to further investigate the mechanism of action. The extract was effective in reducing cortex PGE₂ release and IL-1β gene expression. In the same experimental system, IL-10 and BDNF gene expressions increased, and in HypoE22 cells, the extract decreased the extracellular dopamine level and increased the DAT gene expression due to the direct interaction of parthenolide with the DAT. Overall, the present findings highlight the efficacy of T. parthenium water extract in controlling the inflammatory pathways that occur during cortical-spreading depression. Additionally, the inhibition of the hypothalamic DA release observed in this study further supports the role of dopaminergic pathways as key targets for novel pharmacological approaches in the management of migraine attacks.     

Electrochemical Detection of Epinephrine Based on a Screen-printed Electrode Modified with NiO−ERGO Nanocomposite Film

This study presents a new electrochemical sensor (NiO−ERGO/SPE) for sensitive and selective detection of epinephrine (EPI) on the screen-printed electrode (SPE) which is modified with a nanocomposite film consisting of electrochemically reduced graphene oxide and NiO nanoparticles. After surface functionalization, structural and electrochemical characterization of NiO−ERGO film, DPV signals of NiO−ERGO/SPE towards the oxidation of EPI exhibited a linear correlation in the concentration range of 0.025 μM to 175 μM with a detection limit of 0.015 μM, which reveals NiO−ERGO film is manifested a good electrocatalytic activity for EPI detection compared with the previous reports. The selectivity of NiO−ERGO film was also tested on a very wide scale of possible interferents (ascorbic acid, uric acid, dopamine, lactic acid, phenylalanine, tyrosine, tryptophan, Li⁺, Na⁺, K⁺, Ca²⁺, and Zn²⁺). Moreover, to evaluate the applicability of the proposed sensor for real sample analysis, NiO−ERGO/SPE was successfully utilized for the determination of EPI in pharmaceutical samples.     

Developing a Novel Platelet-Rich Plasma-Laden Bioadhesive Hydrogel Contact Lens for the Treatment of Ocular Surface Chemical Injuries

Permanent injury to corneal limbal stem cells after ocular surface chemical and thermal injuries is a major cause of corneal blindness. In this study, a PRP-laden GelMA hydrogel contact lens is manufactured which is aimed to support the limbal niche after ocular surface insults thereby preventing limbal stem cell failure. GelMA with varying platelet-rich plasma (PRP) concentrations (5%, 10%, and 20%) is photopolymerized using a visible light crosslinking system followed by characterizations of mechanical properties, growth factor release, enzymatic degradation, and in vitro cytotoxicity. The addition of 10% PRP into 10% GelMA hydrogel precursor solution results in the highest tensile and compressive modulus (38 and 110 kPa, respectively) and burst pressure (251±37.66 mmHg). Degradation time varies according to the concentration of the collagenase enzyme tested (0, 2.5, 5, and 40 µg/mL) and is most prolonged with 20% PRP. EGF and TGF-β release profiles suggest an initial burst release followed by sustained release, most consistent in the 10% PRP sample. Although cell viability decreases on day 1, rapid recovery is observed and is approximately 120% after day 21. PRP-laden GelMA in the form of a contact lens may be a promising biomaterial-based treatment approach for the maintenance of limbal epithelial stem cells after ocular surface insults.