Vertex-antimagic labelings of regular graphs

Let G = (V, E) be a finite, simple and undirected graph with p vertices and q edges. An (a, d)-vertex-antimagic total labeling of G is a bijection f from V (G) ∪ E(G) onto the set of consecutive integers 1, 2, . . . , p + q, such that the vertex-weights form an arithmetic progression with the initial term a and difference d, where the vertex-weight of x is the sum of the value f (x) assigned to the vertex x together with all values f (xy) assigned to edges xy incident to x. Such labeling is called super if the smallest possible labels appear on the vertices. In this paper, we study the properties of such labelings and examine their existence for 2r-regular graphs when the difference d is 0, 1, . . . , r + 1.     

Current understanding of ultra-high cycle fatigue

The fatigue life of numerous aerospace, locomotive, automotive and biomedical structures may go beyond 10⁸ cycles. Determination of long life fatigue behavior becomes extremely important for better understanding and design of the components and structures. Initially, before the invention of ultrasonic fatigue testing, most of the engineering materials were supposed to exhibit fatigue life up to 10⁷ cycles or less. This paper reviews current understanding of some fundamental aspects on the development of accelerated fatigue testing method and its application in ultra-high cycle fatigue, crack initiation and growth mechanisms of internal fracture, S-N diagram, fatigue limit and life prediction, etc.     

Thermodynamics of magnetohydrodynamic Brinkman fluid in porous medium

This research article investigates that how heat flow changes versus temperature or time on the rheology of magnetohydrodynamic Brinkman fluid embedded in porous medium for the oscillations of heated plate. A fractional approach namely Caputo–Fabrizio fractional operator is applied for developing the governing partial differential equations of Brinkman fluid flow. The fractional governing partial differential equations have been modeled for temperature distribution, mass concentration and velocity field along with imposed initial and boundary conditions. The solutions are obtained by integral transforms and presented in special and elementary functions. In the limiting sense, the analytical solutions are particularized in the presence and absence of heat and mass transfer, magnetic field and porous medium. The parametric graphs have been depicted for the influence of different embedded rheological parameters on fluid flow. The results show few interesting differences and similarities by comparative analysis for fractional and ordinary Brinkman fluid flow, such as physically higher Prandtl (Pr) number that leads to decay thermal diffusivity which results in the reduction in thermal field; this means that better quality of production can be achieved through proper choice of Prandtl (Pr) and Schmidt (Sc) numbers.

     

α-glucosidase inhibitors isolated from Mimosa pudica L.

The aim of the study was to isolate digestive enzymes inhibitors from Mimosa pudica through a bioassay-guided fractionation approach. Repeated silica gel and sephadex LH 20 column chromatographies of bioactive fractions afforded stigmasterol, quercetin and avicularin as digestive enzymes inhibitors whose IC₅₀ values as compared to acarbose (351.02 ± 1.46 μg mL^?1) were found to be as 91.08 ± 1.54, 75.16 ± 0.92 and 481.7 ± 0.703 μg mL^?1, respectively. In conclusion, M. pudica could be a good and safe source of digestive enzymes inhibitors for the management of diabetes in future.     

Ferromagnetism in GaN doped with transition metals and rare-earth elements: A review

Gallium nitride is a wide band gap semiconductor material that has drawn significant interest due to its potential applications in opto-electronics and spin-tronics devices that can be operated above room temperature. First principle calculations by density functional theory have a key role in the field of materials science research. Theoretical findings on gallium nitride revealed that it shows ferromagnetic behavior doped by transition metals (i.e. 3d and 4d metals) and rare-earth elements. Ferromagnetism developed in gallium nitride by doping 3d (Ti, Cr, Mn, Fe, Co, Ni, and Cu), 4d metals (Ag and Pd), and rare-earth elements (Eu, Gd, and Ce) is discussed in this review. Effect of concentration on magnetic moment is also discussed. The origin of magnetism and exchange interaction that play a vital role in ferromagnetic and anti-ferromagnetic behavior is also explained. P-d exchange mechanism, s-d hybridization, and exchange mechanism are also explained in detail.     

Pavonin: a new five-membered lactone from Adenanthera pavonina Linn. (Mimoaceae)

A new five-membered lactone named pavonin with an exo-cyclic double bond has been isolated from the methanol soluble part of Adenanthera pavonina Linn. belonging to the family Mimoaceae. The structure of pavonin has been established with the aid of spectroscopic techniques including decoupling and HMBC experiments.     

An Overview of the Genetics of Plant Response to Salt Stress: Present Status and the Way Forward

Salinity is one of the major threats faced by the modern agriculture today. It causes multidimensional effects on plants. These effects depend upon the plant growth stage, intensity, and duration of the stress. All these lead to stunted growth and reduced yield, ultimately inducing economic loss to the farming community in particular and to the country in general. The soil conditions of agricultural land are deteriorating at an alarming rate. Plants assess the stress conditions, transmit the specific stress signals, and then initiate the response against that stress. A more complete understanding of plant response mechanisms and their practical incorporation in crop improvement is an essential step towards achieving the goal of sustainable agricultural development. Literature survey shows that investigations of plant stresses response mechanism are the focus area of research for plant scientists. Although these efforts lead to reveal different plant response mechanisms against salt stress, yet many questions still need to be answered to get a clear picture of plant strategy to cope with salt stress. Moreover, these studies have indicated the presence of a complicated network of different integrated pathways. In order to work in a progressive way, a review of current knowledge is critical. Therefore, this review aims to provide an overview of our understanding of plant response to salt stress and to indicate some important yet unexplored dynamics to improve our knowledge that could ultimately lead towards crop improvement.     

Catalytic efficiency of some novel nanostructured heterogeneous solid catalysts in pyrolysis of HDPE

In the present study, the catalytic conversion of high density polyethylene (HDPE) to useful products has been investigated in the presence of BaTiO₃ based catalysts in a micro steel reactor at 350 °C and 30 min reaction time. The catalysts, including BaTiO₃, Pb/BaTiO₃, Co/BaTiO₃ and Pb–Co/BaTiO₃ were prepared in the laboratory by reactive calcination method and characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-rays (EDX), Surface Area Analyzer (SAA) and X-rays Diffractometry (XRD). The product yields (over all yields and yields of liquid, gas and coke/residue) as a function of individual catalyst concentration was studied. The result indicated a promising effect of the catalysts used on conversion to liquid products and their composition in term of carbon range (C₆ – >C₃₀) & hydrocarbon group types (paraffin's, olefins, naphthenics, and aromatics). Among the catalysts used, Pb–Co/BaTiO₃ gave the maximum yield of liquid products (86%) when used in 1 wt % loading. The same catalyst gave the average yield (20–25%) of different range hydrocarbons i.e. C₆–C₁₂, C₁₃–C₁₆, C₁₇–C₂₀ and C₂₀–C₃₀. Inversely, the un-doped BaTiO_3, favored the formation of C₆–C₁₂ and C₁₃–C₁₆ range hydrocarbons, whereas Pb doped BaTiO₃ and Co doped BaTiO₃ enhanced the yield of C₁₃–C₁₆, and C₂₀–C₃₀ range hydrocarbons. Regarding the hydrocarbon group types, all catalysts significantly increased the formation of paraffins and reduced olefins and naphthenes.