Exact solution to peristaltic transport of power-law fluid in asymmetric channel with compliant walls

Effects of compliant wall properties on the peristaltic flow of a non-Newtonian fluid in an asymmetric channel are investigated.The rheological characteristics are characterized by the constitutive equations of a power-law fluid.Long wavelength and low Reynolds number approximations are adopted in the presentation of mathematical developments.Exact solutions are established for the stream function and velocity.The streamlines pattern and trapping are given due attention.Salient features of the key parameters entering into the present flow are displayed and important conclusions are pointed out.     

On the Chromaticity of Quasi Linear Hypergraphs

An h-hypergraph H is said to be quasi linear if every two edges of H intersect in 0 or r vertices (r ≥ 1 and h ≥ 2r + 1). The main result of this paper is the following: if G and H are chromatically equivalent h-hypergraphs, H is quasi linear and h ≥ 3r ? 1, then any two edges of G intersect in 0,1 or r vertices and the result cannot be strengthened. This extends the corresponding result of the first author for linear hypergraphs (case r = 1) [Tomescu in J Combin Theory B2 72: 229–235, 1988]     

Comparative conventional and microwave assisted synthesis of heterocyclic oxadiazole analogues having enzymatic inhibition potential

A comparative microwave assisted and conventional synthetic strategies were applied to synthesize heterocyclic 1,3,4-oxadiazole analogues as active anti-enzymatic agents. Green synthesis of compound 1 was achieved by stirring 4-methoxybenzenesulfonyl chloride ( a ) and ethyl piperidine-4-carboxylate ( b ). Compound 1 was converted into respective hydrazide ( 2 ) by hydrazine and then into 1,3,4-oxadiazole ( 3 ) by CS₂ on reflux. The electrophiles, N-alkyl/aralkyl/aryl-2-bromopropanamides ( 6a–p ) were synthesized and converted to N-alkyl/aralkyl/aryl-2-propanamide derivatives ( 7a–p ) by reaction with 3 under green chemistry. Microwave assisted method was found to be effective relative to conventional method. ¹³C-NMR, ¹H-NMR and IR techniques were availed to corroborate structures of synthesized compounds and then subjected to screening against lipoxygenase (LOX), α-glucosidase, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. A number of compounds presented better potential against these enzymes. The most active compounds against LOX and α-glucosidase enzymes were subjected to molecular docking study to explore their interactions with the active sites of the enzymes.     

Radon concentration in drinking water sources of the Main Campus of the University of Peshawar and surrounding areas, Khyber Pakhtunkhwa, Pakistan

Radon and its progenies in indoor environment have been identified as the main sources of radiation dose to the people from natural radioactive sources. Presence of radon in drinking water causes radiation related health hazards both through inhalation and ingestion. In this study 36 drinking water samples from taps, boreholes and deep tube wells within the Main Campus of the University of Peshawar and adjoining area were analyzed with RAD7 electronic device for radon content determination. These water samples have a mean, maximum and minimum radon value of 8.8 ± 0.8, 18.2 ± 1.0, and 1.6 ± 0.3 Bq L⁻¹, respectively. Eleven drinking water samples analyzed have radon levels in excess of the EPA recommended maximum contaminant level (MCL) of 11.1 Bq L⁻¹. These include 89% from tube wells, 8% from tap water, and 50% from shallow boreholes. Radon levels of about 31% of the total samples used by the inhabitants of the study area are higher than the EPA advised level of 11.1 Bq L⁻¹. The annual effective dose from radon in water due to its ingestion and inhalation per individual has also been estimated. The mean radon concentration and mean annual effective dose due to radon in water of this study have been compared with the mean radon concentration and mean annual effective dose of earlier investigators due to radon in water from different localities of India and Pakistan. The mean annual effective doses of all the samples are lower than the reference level of 0.1 mSv a⁻¹ for drinking water of WHO and EU Council. It has been concluded that drinking water of the study area is generally safe as far as radon related health hazards are concerned with the exception of a few isolated cases. It has been found that radon levels within the region have a positive correlation with depth of the water sources.     

Efficient synthesis of purines by inverse electron-demand Diels-Alder reactions of 1-substituted-1H-imidazol-5-amines with 1,3,5-triazines

The reaction of 1,3,5-triazine and 2,4,6-tri(trifluoromethyl)-1,3,5-triazine with in situ generated 1-substituted 5-amino-1H-imidazoles led to a set of functionalized purines. The developed practical route could serve as a fundament for the preparation of related ADA inhibitors.     

Alleviation of adverse effects of drought stress on growth and some potential physiological attributes in maize (Zea mays L.) by seed electromagnetic treatment

Effects of varying preseed magnetic treatments on growth, chlorophyll pigments, photosynthesis, water relation attributes, fluorescence and levels of osmoprotectants in maize plants were tested under normal and drought stress conditions. Seeds of two maize cultivars were treated with different (T0 [0 mT], T1 [100 mT for 5 min], T2 [100 mT for 10 min], T3 [150 mT for 5 min] and T4 [150 mT for 10 min]) electromagnetic treatments. Drought stress considerably suppressed growth, chlorophyll a and b pigments, leaf water potential, photosynthetic rate (A), stomatal conductance (g(s)) and substomatal CO(2) concentration (C(i)), while it increased leaf glycinebetaine and proline accumulation in both maize cultivars. However, pretreated seeds with different magnetic treatments significantly alleviated the drought-induced adverse effects on growth by improving chlorophyll a, A, E, g(s), C(i) and photochemical quenching and nonphotochemical quenching, while it had no significant effect on other attributes. However, different magnetic treatments negatively affected the g(s) and C(i) particularly in cv. Agaiti-2002 under drought stress conditions. Of all magnetic treatments, 100 and 150 mT for 10 min were most effective in alleviating the drought-induced adverse effects. Overall, preseed electromagnetic treatments could be used to minimize the drought-induced adverse effects on different crop plants.     

Synthesis of stable cadmium sulfide nanoparticles using surfactin produced by Bacillus amyloliquifaciens strain KSU-109

In this study, a surfactin was extracted from a novel surfactant producing bacterial strain Bacillus amyloliquifaciens KSU-109, isolated from rhizosphere of date palm (Phoenix dactylifera), and characterized based on 16Sr RNA and sfp genes using Blastn, Blastx and phylogenetic analyses. The study was performed to obtain a renewable bioresource for surfactin production, and its application in nanotechnology as a non-hazardous and environmentally compatible nanoparticle (NP) stabilizer. The strain KSU-109 produced the surfactin with an average yield of 160 mg/L with strong surfactant activity, reducing the surface tension of the medium from 72 mN/m to 29.3 mN/m. The surfactin preparation was used for synthesizing the cadmium sulfide nanoparticles (CdS-NPs) by mixing 0.005% surfactin with 1mM Cd(NO(3))(2) in 1:1 ratio (v/v) and 10mM Na(2)S solution at pH 7.2 and ambient temperature, which were stable up to 120 days. The surfactin stabilized CdS-NPs were characterized using XRD, TEM, and spectroscopic techniques. The data revealed a significant role of surfactin as a stabilizer and capping agent, which also causes phase transition to yield the cubic/hexagonal CdS-NPs of average size of 3-4 nm. The results elucidated the significance of biocompatible and biodegradable surfactin as an effective and inexpensive stabilizing agent for developing stable CdS nanoparticles.     

Optical spectroscopy studies of the interaction between thiophanate methyl and human serum albumin for biosensor applications

Optical properties of the interaction between thiophanate methyl and human serum albumin have been investigated for biosensor applications. The interaction between human serum albumin (HSA) and thiophanate methyl (MT) was investigated by UV-Vis absorption spectra and atomic force microscopy. The optical constants (refractive index, absorption index, band gap and dielectric properties) of HSA, MT and MT+HSA films were determined using absorbance, transmittance and reflectance spectra. The refractive index dispersion curve (>530 nm) exhibits the normal dispersion. The refractive index of the MT+HSA is higher than both HSA and MT alone due to the highest reflectance of the mixture of MT and HSA. This behavior is indicative of the complex formation between the MT and HSA.     

Synthesis and Blood Glucose Lowering Activity of Novel Benzenesulfonyl-Urea Derivatives

Treatment of the pyridazinone derivatives ( 1a, 1b ) with ethyl chloroformate afforded novel carbamates ( 2a, 2b ). Subsequent treatment of 2a, 2b with appropriate amines gave novel benzenesulfonylurea derivatives ( 3a–i ). All these compounds were characterized on the basis of ¹ H NMR, IR, Mass spectral data and elemental analysis results. Preliminary biological testing of urea derivatives revealed that some compounds possess significant blood sugar lowering activity. Four compounds ( 3c, 3f, 3g , and 3h ) were found to have promising blood glucose lowering activity and may be used as lead compounds for developing new antidiabetic drugs.     

Production of aligned helical polymer nanofibers by electrospinning

A new and simple electrospinning method has been developed for producing aligned helical polymer nanofibers. Aligned helical polycaprolactone (PCL) nanofibers were prepared by this method. The helical fibers were collected by a tilted glass slide. The morphology and loop diameters of the helical structures are dependant on the PCL solution concentration and the loop diameters are in the range of 6.9-14.9 μm for the concentration range of 4.7%-10%. The three-dimensional helical structures were obtained at the high solution concentration of 10%. These helical structures were formed by jet buckling due to mechanical instability when hitting collector surface. Formation of the helical structures is dependent on the obliquity of the tilted glass slide and distance away from the syringe needle. The converging electrical field generated by a tip collector plays an important role in the alignment of the helical structures.