A strategy for designing "multi-prong" enzyme inhibitors by incorporating selective ligands to the liposomal surface

We offer a novel strategy for designing "multi-prong" inhibitors of enzymes by incorporating selective ligands on the liposomal surface.     

Finite element analysis of the demagnetization effect and stress inhomogeneities in magnetic shape memory alloy samples

This paper is concerned with the finite element analysis of boundary value problems involving nonlinear magnetic shape memory behavior, as might be encountered in experimental testing or engineering applications of magnetic shape memory alloys (MSMAs). These investigations mainly focus on two aspects: first, nonlinear magnetostatic analysis, in which the nonlinear magnetic properties of the MSMA are predicted by the phenomenological internal variable model previously developed by Kiefer and Lagoudas, is utilized to investigate the influence of the demagnetization effect on the interpretation of experimental measurements. An iterative procedure is proposed to deduce the true constitutive behavior of MSMAs from experimental data that typically reflect the shape-dependent system response of a sample. Secondly, the common assumption of a homogeneous Cauchy stress distribution in the MSMA sample is tested. This is motivated by the expectation that the influence of magnetic body forces and body couples caused by field matter interactions may not be negligible in MSMAs that exhibit blocking stresses of well below 10?MPa. To this end, inhomogeneous Maxwell stress distributions are first computed in a post-processing step, based on the magnetic field and magnetization distributions obtained in the magnetostatic analysis. Since the computed Maxwell stress fields, though allowing a first estimation of the influence of the magnetic force and couple, do not satisfy equilibrium conditions, a finite element analysis of the coupled field equations is performed in a second step to complete the study. It is found that highly non-uniform Cauchy stress distributions result under the influence of magnetic body forces and couples, with magnitudes of the stress components comparable to externally applied bias stress levels.     

Antitumour activity of Terminalia arjuna leaf against Ehrlich ascites carcinoma in mice

Terminalia arjuna Roxb. (Combretaceae), commonly known as 'Arjuna', is a large tree occurring throughout the Indian peninsula. This study was undertaken to evaluate the methanol extract of T. arjuna leaf (META) for antitumour activity against Ehrlich ascites carcinoma (EAC) in Swiss albino mice. Twenty-four hours after intraperitonial inoculation of tumour (EAC) cells in mice, META was administered at 100 and 200?mg?kg(-1) body weights for 9 consecutive days. On day 10, half of the mice were sacrificed and the rest kept alive for an assessment of the increase in life span. The antitumour effect of META was assessed by evaluating tumour volume, tumour weight, viable and non-viable tumour cell counts, median survival time and increase in life span of EAC-bearing hosts. Haematological profiles were estimated. META showed a significant (p<0.001) decrease in tumour volume, tumour weight and viable cell count, and also increased the life span of EAC-bearing mice. Haematological profiles were significantly (p<0.001) restored to normal levels in META-treated mice compared to the EAC control. Therefore, from this study, it can be concluded that T. arjuna leaf exhibited remarkable antitumour activity against EAC in Swiss mice.     

Heat Transfer from a Hot Moving Steel Plate by Air-Atomized Spray Impingement

Air-atomized spray cooling of a hot moving AISI 304 steel plate of 6 mm thickness has been investigated experimentally by varying water flow rate and plate velocity at a fixed nozzle-to-plate distance. It is found that the heat transfer coefficient is a non-linear function of surface temperature. The result shows that the cooling rate increases with an increase in the water flow rate. The highest cooling rate has been found for the static plate, whereas for a moving plate, an increasing cooling rate trend has been observed with increasing plate velocity.     

A newly developed highly selective ratiometric fluoride ion sensor: spectroscopic, NMR and density functional studies

A new easy-to-synthesize chemosensor, 3,3'-bis(indolyl)-4-chlorophenylmethane (hereafter S), was designed, synthesized and employed as a selective optical chemosensor for fluoride ions.(1)H NMR and density functional studies on the system have been carried out to determine the nature of the interaction between S and X(-) (X = inorganic anions) responsible for the significant fluoride-induced changes in the absorption properties of S. The experimental results reveal that abstraction of an acidic proton of S by the fluoride ion, leading to the formation of anionic species, is responsible for the spectral changes. These changes allow signaling for the fluoride ion to detect and estimate the concentration of fluoride ion present even at the submicromolar level, accurate up to 2 μM. Calculations of the transition energies of S, S(-), and S···F(-) (hydrogen bonded complex) show that only S(-) is responsible for the long-wavelength absorption band in the presence of F(-).     

Effect of ex-situ hydrogen passivation on the structural properties of e-beam evaporated amorphous silicon thin film for solar cell applications

Thin-film photovoltaics greatly reduce the semiconductor material content in the finished product, using 150–200 times less material as compared with conventional Si wafer based cells. Electron beam evaporation (e-beam), a non-ultra-high vacuum technique has the potential for being inexpensive, and simpler process for a-Si deposition. It offers specific advantages such as high Si deposition rate (up to 1 μm/min), excellent Si source material usage, avoidance of toxic gases, and simple sample preparation conditions. In this work, we report the growth of a-Si films using e-beam at a growth rate exceeding 30 Å/s (1–5 Å/s for conventional PECVD process). We report the effect of hydrogen passivation on amorphous silicon network and on silicon-bonded hydrogen configuration under ex-situ hydrogenation in hydrogen plasma. The hydrogen concentration and silicon-hydrogen bonding configuration was evaluated using nuclear reaction analysis (NRA) and Fourier transform infrared spectroscopy (FTIR). Hydrogen plasma treatment shows an increase in the monohydride bond concentration with substrate temperature, and is corroborated by our FTIR investigation, in addition to reducing clustered monohydride bonds or polyhydride bonds in a-Si:H film. Raman analysis indicates reduction in silicon bond angle as well as the bond distance, both leading to significant structural improvement in short-range and medium range order in the amorphous phase. Thus, ex-situ hydrogenation clearly demonstrates the possibility of comparable hydrogen passivation in e‐beam evaporated a-Si films with high growth rate. One can easily extrapolate this result to microcrystalline film growth, assuming the structural improvement of the silicon network preceding the microcrystalline nucleation, where ex-situ passivation is most effective. Thus ex-situ hydrogenation opens up new possibilities in minutely tailoring the a:Si film properties especially for solar cell applications.     

Exciplex formation and energy transfer in a self-assembled metal-organic hybrid system

Exciting assemblies: A metal-organic self-assembly of pyrenebutyric acid (PBA), 1,10-phenanthroline (o-phen), and Mg(II) shows solid-state fluorescence originating from a 1:1 PBA-o-phen exciplex. This exciplex fluorescence is sensitized by another residual PBA chromophore through an excited-state energy-transfer process. The solvent polarity modulates the self-assembly and the corresponding exciplex as well as the energy transfer, resulting in tunable emission of the hybrid (see figure).     

Supersymmetric Isospectral Formalism for the Calculation of Near-Zero Energy States: Application to the Very Weakly Bound 4He Trimer Excited State

We propose a novel mathematical approach for the calculation of near-zero energy states by solving potentials which are isospectral with the original one. For any potential, families of strictly isospectral potentials (with very different shape) having desirable and adjustable features are generated by supersymmetric isospectral formalism. The near-zero energy Efimov state in the original potential is effectively trapped in the deep well of the isospectral family and facilitates more accurate calculation of the Efimov state. Application to the first excited state in ⁴He trimer is presented.     

Global stability and bifurcation analysis of a delay induced prey-predator system with stage structure

This paper describes a delay induced prey–predator system with stage structure for prey. The dynamical characteristics of the system are rigorously studied using mathematical tools. The coexistence equilibria of the system is determined and the dynamic behavior of the system is investigated around coexistence equilibria. Sufficient conditions are derived for the global stability of the system. The optimal harvesting problem is formulated and solved in order to achieve the sustainability of the system, keeping the ecological balance, and maximize the monetary social benefit. Maturation time delay of prey is incorporated and the existence of Hopf bifurcation phenomenon is examined at the coexistence equilibria. It is shown that the time delay can cause a stable equilibrium to become unstable and even a switching of stabilities. Moreover, we use normal form method and center manifold theorem to examine the nature of the Hopf bifurcation. Finally, some numerical simulations are given to verify the analytical results, and the system is analyzed through graphical illustrations.     

Diethyl 1‐(4‐fluoro­phenyl)‐3‐(2‐furyl)‐5‐oxopyrrolidine‐2,2‐di­carboxyl­ate and diethyl 1‐(3,4‐di­chloro­phenyl)‐3‐(2‐furyl)‐5‐oxopyrrolidine‐2,2‐di­carboxyl­ate

The title compounds, C₂₀H₂₀FNO₆ and C₂₀H₁₉Cl₂NO₆, respectively, may exhibit bioactivity. In these compounds, the pyrrolidine ring adopts a conformation intermediate between envelope and half‐chair. Only one of the two ethoxy­carbonyl side chains is nearly planar. Centrosymmetric pairs are formed, and the crystal structure is stabilized by weak C—H⋯O hydrogen bonds and van der Waals interactions.