Batch kinetics, isotherm and thermodynamic studies of adsorption of strontium from aqueous solutions onto low cost rice-straw based carbons.

Present study explored the feasibility of using waste rice-straw based carbons as adsorbent for the removal of strontium under different experimental conditions. The batch sorption is studied with respect to solute concentration (2.8 - 110 mg/L), contact time, adsorbent dose (2.5 - 20 g/L) and solution temperature (25 - 55oC). The Langmuir and Dubinin-Radushkevich adsorption models were applied to experimental equilibrium data and isotherm constants were calculated using linear regression analysis. A comparison of kinetic models applied to the adsorption of strontium on rice-straw carbon was evaluated for the pseudo-second-order, Elovich, intraparticle diffusion and Bangham’s kinetics models. The experimental data fitted very well the pseudosecond-order kinetic model and also followed by intra-particle diffusion model, whereas diffusion is not only the rate-controlling step. The results show that the sorption capacity increases with an increase in solution temperature from 25 to 55 oC. The thermodynamics parameters were evaluated. The positive value of ΔH (40.93 kJ) indicated that the adsorption of strontium onto RS1 carbon was endothermic, which result was supported by the increasing adsorption of strontium with temperature. The positive value of ΔS (121.8 kJ/mol) reflects good affinity of strontium ions towards the rice-straw based carbons. The results have establishedgood potentiality for the carbons particles to be used as a sorbent for the removal of strontium from wastewater

Age-of-acquisition effects:a literature review

Age of acquisition (AoA) refers to the age at which people learn a particular item and the AoA effect refers to the phenomenon that early-acquired items are processed more quickly and accurately than those acquired later. Over several decades, the AoA effect has been investigated using neuroscientific, behavioral, corpus and computational techniques. We review the current evidence for the AoA effect stemming from a range of methodologies and paradigms and apply these findings to current explanations of how and where the AoA effect occurs. We conclude that the AoA effect can be found both in the connections between levels of representations and within these representations themselves, and that the effect itself occurs through the process of the distinct coding of early and late items, together with the nature of the connections between levels of representation. This approach strongly suggests that the AoA effect results from the construction of perceptual-semantic representations and the mappings between representation

Phonological precision for word recognition in skilled readers

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Synthesis and Characterization of Dihydrouracil Analogs Utilizing Biginelli Hybrids

Dihydrouracil presents a crucial intermediate in the catabolism of uracil. The vital im-portance of uracil and its nucleoside, uridine, encourages scientists to synthesize novel dihydroura-cils. In this paper, we present an innovative, fast, and effective method for the synthesis of dihy-drouracils. Hence, under mild conditions, 3‐chloroperbenzoic acid was used to cleave the carbon– sulfur bond of the Biginelli hybrids 5,6‐dihydropyrimidin‐4(3H)‐ones. This approach led to thirteen novel dihydrouracils synthesized in moderate‐to‐high yields (32–99%)

Lorcaserin vs. Phentermine among non-surgical and surgical obese patients: Anthropometric, glycemic, lipid, safety and cost outcomes

Background To evaluate effectiveness, safety, and costs of Lorcaserin vs. phentermine among obese non–surgical and surgical patients (post bariatric surgery). Methods This retrospective study retrieved charts of all patients (January 2013–June 2016) who received Lorcaserin or phentermine for 3 months. The study assessed anthropometric, glycemic, and lipid changes, as well as side effects and cost of medications among overweight and obese non-surgical (n = 83) and surgical patients (n = 46). These two patient groups were compared using Chi-square (χ2) and unpaired‘t’ test for qualitative and quantitative variables respectively. Results At 3 months, among the non-surgical group, Phentermine patients had greater percentage of total weight loss (TWL%) (7.65 ± 8.26 vs. 2.99 ± 3.72%, P = 0.003), and greater BMI reduction (−3.16 ± 3.63 vs. −1.15 ± 1.53 kg/m2, P = 0.003) than Lorcaserin. Within the surgical group, Lorcaserin patients had significantly smaller TWL% (1.86 ± 5.06 vs. 7.62 ± 9.80%, P = 0.012), and smaller BMI reduction (−0.74 ± 1.80 vs. −3.06 ± 4.08 kg/m2, P = 0.012) than Phentermine. Lorcaserin exhibited significant total cholesterol and LDL improvements only among surgical patients with significant weight reduction (≥5% TW). Both medications were not associated with glycemic improvements among non-surgical and surgical groups. Phentermine had slightly more side effects but was less expensive. Conclusions Among both patient groups, phentermine was more effective in achieving weight loss. Lorcaserin showed dyslipidemia improvements only among surgical patients who achieved significant weight reduction. Anti-obesity medications as part of weight management programs can result in weight loss among non-surgical and surgical patients, or halt weight regain among surgical patients. This is the first study to evaluate the effectiveness and safety of two anti-obesity medications (lorcaserin vs. phentermine) among two distinct obese patient groups, non-surgical and surgical patients

Spectrophotometric Complex formation Study of Murexide with Nickel and Cobalt in Aqueous Solution

In the present study, the formation constant and the stoichiometry of murexide complexes with Co (II) and Ni (II) have been determined spectrophotometrically in aqueous solution at 25oC. Two experimental parameters governed the complex formation, pH and time, have been investigated. The formation and stoichiometry constants have been determined by two methods: Job's and mole ratio's methods. The absorption maxima for Co-murexide and Ni-murexide complexes were: 480, 460 nm, respectively. The two Spectrophotometric methods confirm the formation of 2:1 (M:L) complexes with stability arrange of: Co > Ni. The formation constants (Kf) determined by the Job's method were as follows: 2.06x1014 and 1.21x1011 for Co-murexide and Ni-murexide, respectively. Also, using mole ratio's method, the formation constants were found to be:  9.18x1011 and 6.01x1011. Molar absorptivity values of the studied complexes have also been determined (by Job's and mole ratio's methods) and the average values were: 18235 and 13284 l/mol.cm for Co and Ni, respectively

ADSORPTION OF Co (II) IONS FROM AQUEOUS SOLUTION ONTO TEA AND COFFEE POWDER: EQUILIBRIUM AND KINETIC STUDIES

Adsorption of Co(II) ions from aqueous solutions onto Tea and Coffee powders has been examined in a batch adsorption process. The adsorption of Co(II) ions was found to be dependent on contact time, pH of solution, initial metal ion concentration, and adsorbent dose. The experimental equilibrium adsorption data were studied by Langmuir, Freundlich, Temkin and Dubinin-Radushkevic isotherms models. The Langmuir model display demonstrated a superior fit than the other three models by higher correlation coefficient, R2. The maximum adsorption capacities calculated from the Langmuir isotherm model were 244 mg/g, for both coffee and tea at optimum circumstances. The kinetic studies denoted that the adsorption process of Co(II) ions followed well pseudo-second-order model. According to the adsorption capacity, coffee and tea powder considered as an effective, low cost, and environmentally friendly adsorbent for the removal of Co(II) ions from aqueous solutions