Measurement of half-lives for 87m,gY and 196m,g,194Au produced from the photon and neutron induced reactions of 89Y and 197Au

Journal of Radioanalytical and Nuclear Chemistry - We have measured the half-lives of 87mY and 87gY produced from the 89Y(γ, 2n) and 89Y(n, 3n) reactions with the bremsstrahlung end-point...     

Generalization of the double reduction theory

In a recent work Sjöberg (2007, 2008) [1], [2] remarked that generalization of the double reduction theory to partial differential equations of higher dimensions is still an open problem. In this note we have attempted to provide this generalization to find invariant solution for a non linear system of $q$th order partial differential equations with $n$ independent and $m$ dependent variables provided that the non linear system of partial differential equations admits a nontrivial conserved form which has at least one associated symmetry in every reduction. In order to give an application of the procedure we apply it to the nonlinear (2+1) wave equation for arbitrary function $f\left(u\right)$ and $g\left(u\right)$.     

Global Aspects of Age-Structured Cigarette Smoking Model

Smoking impacts health and as a result creates several problems related to age which means smoking has a strong correlation with age. Keeping this problem in view, we consider the global asymptotic properties of age-structured smoking model. First, we formulate the model and present the existence and uniqueness of solution. Then we discuss the equilibrium points and construct the Lyapunov function to examine global stability of the free smoking and positive smoking equilibrium points. Finally, we fixed the age factor and use the non-standard finite difference (NSFD) scheme for numerical solutions and compare our results obtained with RK4 and ODE45 graphically with the help of MATLAB.     

Synthesis of Cholesterol-Conjugated Magnetic Nanoparticles for Purification of Human Paraoxonase 1

Human serum paraoxonase 1 (PON1) is known as an antioxidant and is also involved in the detoxification of many compounds. In this study, a novel purification strategy was employed to purify the PON1 by using cholesterol-conjugated magnetic nanoparticles. Magnetic nanoparticles were synthesized and conjugated with cholesterol through diazotized p-aminohippuric acid. In Fourier transform infrared spectrum of cholesterol-p-aminohippuric acid-Fe₃O₄ nanoparticles, the appearance of peaks at 3,358.3, 1,645 cm⁻¹, and at 2,334.9 cm⁻¹ confirmed the conjugation. The molecular weight of purified PON1 was nearly 45 kDa on sodium dodecyl sulfate (SDS)–polyacrylamide gel electrophoresis (PAGE), and isoelectric point was 5.3. The specific activity was 438 U mg⁻¹ protein, and the purification fold was 515 with 73% yield. The K _m values were 1.3 and 0.74 mM with paraoxon and phenyl acetate, respectively. Western blot of 2D-PAGE confirmed the homogeneity and stability of the enzyme. Mg⁺², Mn⁺², glycerol, (NH₄)₂SO₄, PEG 6000, Triton X-100, and phenylmethylsulfonyl fluoride did not show any effect on activity. Pb⁺², Co⁺², Zn²⁺, ethanol, β-mercaptoethanol, and acetone reduced the activity while Ni²⁺, Cd²⁺, Cu²⁺, iodoacetic acid, SDS, dimethylformamide, DMSO inhibited the activity. In vitro enzyme activity was slightly reduced by acetyl salicylic and acetaminophen and reduced 50% with amino glycosides and ampicillin antibiotics at concentrations of 0.6 and 30 mg ml⁻¹, respectively. This is the first report for the synthesis of cholesterol-conjugated magnetic nanoparticles for simple purification of PON1 enzyme.     

Solid state NMR studies of photoluminescent cadmium chalcogenide nanoparticles

Solid state (113)Cd, (77)Se, (13)C and (31)P NMR have been used to study a number of Cd chalcogenide nanoparticles synthesized in tri-n-octyl-phosphine (TOP) with different compositions and architectures. The pure CdSe and CdTe nanoparticles show a dramatic, size-sensitive broadening of the (113)Cd NMR line, which can be explained in terms of a chemical shift distribution arising from multiple Cd environments. From (13)C NMR, it has been discovered that TOP, or its derivatives such as TOPO (trioctylphosphine oxide), is rapidly moving about the surface of the nanoparticles, indicating that it is relatively weakly bound as compared to other materials used as surface ligands, such as hexadecylamine. (31)P NMR of the nanoparticles shows at least five species arising from coordination of the ligands to different surface sites. (113)Cd NMR of CdSeTe alloy and layered nanoparticles has provided crucial information which, in conjunction with results from other techniques (especially optical characterization), has made it possible to develop a detailed picture of the composition and structure of these materials: (i) a true CdSeTe homogeneous alloy nanoparticle, (ii) a nanoparticle segregated into an alloy core region rich in Te, with a CdSeTe (close to 1 : 1 Se : Te) alloy shell and (iii) a CdSe/CdTe/CdSe layered nanoparticle in which the CdTe layer contains a small amount of Se and which forms a Quantum Dot Quantum Well (QDQW) system. The results demonstrate that solid state NMR is a vital tool in the arsenal of characterisation techniques available for nanomaterials.     

A new simple synthesis of poly(thiophene-methine)s

Acid-promoted polycondensation of 3,4-(ethylenedioxy)thiophene-2-carbaldehyde leads to a conjugated heavily p-doped poly(thiophene-methine), which can be dedoped leading to a low band-gap neutral polymer.     

Study on the normalized Laplacian of a penta-graphene with applications

Let L _n denote a linear pentagonal chain with 2n pentagons. The penta-graphene (penta-C), denoted by R _n is the graph obtained from L _n by identifying the opposite lateral edges in an ordered way, whereas the pentagonal Möbius ring is the graph obtained from the L _n by identifying the opposite lateral edges in a reversed way. In this paper, through the decomposition theorem of the normalized Laplacian characteristic polynomial and the relationship between its roots and the coefficients, an explicit closed-form formula of the multiplicative degree-Kirchhoff index (resp. Kemeny's constant, the number of spanning trees) of R _n is obtained. Furthermore, it is interesting to see that the multiplicative degree-Kirchhoff index of R _n is approximately of its Gutman index. Based on our obtained results, all the corresponding results are obtained for .     

The effect of hydration on the thermal behaviour of hydrophilic non-aqueous gels stabilised by Carbopol 974P

A thermal analysis of the effect of hydration of non-aqueous polymer-stabilised gels was investigated using differential scanning calorimetry (DSC). The interaction of water with the polymer and its distribution within the gel are critical to the physicochemical behaviour of the gel, and consequently affects the utility of the gel matrix as a drug delivery vehicle. Addition of water at levels up to and including 50% (w/w) did not result in an observable freezing event in the thermogram. However, at 60 and 80% (w/w) water, phase transitions were observed, the magnitude of which were found to be independent of the annealing time within the range used. The observed melting enthalpies increased as the water concentration increased for all formulations, but were always smaller than that of pure water. There was no evidence of multiple transitions that might be attributed to different populations of water molecules. However, the results demonstrate that DSC can be employed to differentiate between freezable and non-freezable water, in these particular formulations.