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  • Author: M.R. Kamal, x
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Abstract

Cerulean Warblers (Setophaga cerulea) are among the fastest declining Nearctic-Neotropical migrant wood-warblers (Parulidae) in North America. Despite ongoing conservation efforts, little is known about their non-breeding distribution. In June 2016-2018, we deployed geolocators (n = 30) on adult male Cerulean Warblers in Indiana, USA, to track annual movements of individuals. Recovered geolocators (n = 4) showed that Cerulean Warblers occurred broadly throughout northern South America. Autumn migration lasted 44-71 days (n = 4), whereas spring migration lasted 37-41 days (n = 3). The average migration distance was 5268 km. During autumn migration, Cerulean Warblers made 1-4 stopovers (i.e., ≥2 days; n = 4) and 1-2 stopovers during spring migration (n = 3). When crossing the Gulf of Mexico during autumn migration, two birds stopped over after crossing, but not beforehand. Two others navigated through the Caribbean rather than crossing the Gulf of Mexico. During spring migration, one individual stopped after crossing, one individual stopped before crossing, and one individual stopped before and after crossing the Gulf of Mexico. No birds migrated through the Caribbean Islands during spring migration. These results represent novel information describing annual movements of individual Cerulean Warblers and will inform conservation efforts for this declining species.

An efficient and direct synthesis of 1-thia-5-azaspiro[5.5]undec-2-ene is described, and the basecatalyzed recyclization of this compound was studied. The products have been characterized by elemental analyses, and IR, MS, 1H NMR, and 13C NMR spectroscopy

Abstract

Effective use of salt affected soils needs the development of the most efficient and suitable reclamation technology to optimize farm management and better crop yields. Different chemical methods and amendments are used to reclaim the salt affected soils and after reclamation such soils may be used for sustainable agricultural production. Choice of a chemical amendment depends on its availability, cost, handling and time of application. Application of sulfur is very effective technique to suppress the uptake of undesired toxic elements and to improve the quantity and quality of produce in salt affected soils. So, a three-year field experiment was carried out to evaluate the comparative reclamation efficiency of two sulfur sources, i.e elemental sulfur and gypsum to improve the soil conditions by reducing the salinity/sodicity impact and yield characteristics of rice and wheat crop. A saline-sodic field {(ECe = 6.10 dS m−1, pHs = 9.21 and SAR = 41.67 (mmol L−1)1/2, SO4-S = 16.0 (mg kg−1) and soil gypsum requirement (SGR) of 9.10 t ha−1 for 0-15 cm soil depth} was selected. The treatments included were: control, gypsum application @ 100 SGR, S application @ 25, 50, 57, 100 and 125 % of SGR. Statistical analysis of three-year pooled data showed that varying levels of sulfur and gypsum significantly improved soil properties and rice-wheat yield than control, however, gypsum @ 100% of soil GR was at par with S @ 125 and 100% of SGR in term terms of improving yield component of both test crops and reducing soil pHs, ECe and SAR. Efficiency of treatment could be arranged as gypsum @ 100% SGR = S @ 125 % of SGR= S @ 100% of SGR> S @ 75 % of SGR> S @ 50 % of SGR> S @ 25% of SGR>control.

Abstract

A series of N-(2-(benzoyl/4-chlorobenzoyl)-benzofuran- 3-yl)-2-(substituted)-acetamide derivatives (4a-l, 5a-l) was synthesized in good yield. All synthesized compounds were in agreement with elemental and spectral data. The anticonvulsant activity of all synthesized compounds was assessed against the maximal electroshock induced seizures (MES) model in mice. Neurotoxicity was evaluated using the rotarod method. The majority of compounds exhibited anticonvulsant activity at a dose of 30 mg kg-1 body mass during 0.5-4 h, indicating their ability to prevent seizure spread at low doses. Relative to phenytoin, [N-(2-(4-chlorobenzoyl)benzofuran-3-yl)-2-(cyclohexyl( methyl) amino)-acetamide] (5i) and [N-(2-(4-chlorobenzoyl)benzofuran-3-yl)-2-(4-methylpiperidin-1- yl)-acetamide] (5c) demonstrated comparable relative anticonvulsant potency of 0.74 and 0.72, respectively, whereas [(N-(2-(4-chlorobenzoyl)benzofuran-3-yl)-2-(4-(furan-2-carbonyl)-piperazin-1-yl)-acetamide] (5f) exhibited the lowest relative potency of 0.16. The ALD50 of tested compounds ranged from 1.604 to 1.675 mmol kg-1 body mass. The ED50 of synthesized compounds ranged from 0.055 to 0.259 mmol kg-1 (~23.4 to 127.6 mg kg-1) body mass. The pharmacophore mapping of the examined compounds on standard drugs (phenobarbital, phenytoin, ralitolin and carbamazepine) strongly suggests that these compounds may exert their anticonvulsant activity via the same established mechanism as that of known drugs.

Abstract

In this work different shapes of carbon nanofibers (CNFs) were successfully synthesised on a treated commercial steel substrate by catalytic chemical vapour deposition (CCVD) utilising ethanol at 700 °C. The formation of the nanofibers with average diameter of 200–400 nm was confirmed via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The BET surface area, pore volume and pore size of the obtained CNFs were sequentially: 182 m2/g, 10.5 cm3/g and 103.3 Å as determined by nitrogen adsorption analysis. The influence of the surface treatment on the size and shape of CNFs was investigated and the results indicated a positive correlation that can be employed to tailor CNFs of desired morphology. Accordingly, a growth mechanism due to the deposition of carbonaceous materials on large size nanoparticles was proposed. As the CCVD is a facile and economical route for CNFs synthesis, thus, it can be efficiently adopted for the growth of CNFs on pretreated steel substrates as proved by this study.

Abstract

Coiled multiwall carbon nanotubes (MWCNTs) were prepared on Fe, Co, and Ni metal oxides supported on α-Al2O3 using urea as fuel and catalyst surface modifying agent by catalytic chemical vapour deposition (CCVD). The shape of the nanotubes was influenced by the addition of urea, where coiled and uncoiled tubes were obtained in the presence and absence of urea, respectively. The MWCNTs were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption analysis. The coiling/uncoiling of the nanotubes was visualized from the SEM and TEM images of the prepared specimens. The XRD data showed the characteristic peaks of the nanotubes. BET analysis of the coiled tubes revealed 85.57 m2 g−1 surface area with a pore diameter 102.2–110.8 Å. A mechanism for the nanotubes coiling is suggested.