A Note on Convergence of the Equi-Energy Sampler

This paper studies maximum likelihood estimation for a parameterised elliptic diffusion in a manifold. The focus is on asymptotic properties of maximum likelihood estimates obtained from continuous time observation. These are well known when the underlying manifold is a Euclidean space. However, no systematic study exists in the case of a general manifold. The starting point is to write down the likelihood function and equation. This is achieved using the tools of stochastic differential geometry. Consistency, asymptotic normality and asymptotic optimality of maximum likelihood estimates are then proved, under regularity assumptions. Numerical computation of maximum likelihood estimates is briefly discussed.     

Widened derangements and generalized Laguerre polynomials

The Ramanujan Journal - Let $$D_h$$ , $$E_k$$ and $$F_{\alpha }$$ be sets of size $$h,k,\alpha $$ respectively, with $$k \le h$$ . We define a strongly widened derangement to be a permutation of...     

Conformational and Electronic Interaction Studies of Some β-Ketosulfoxides

ABSTRACT.

The analysis of the carbonyl I.R. band and the U.V. phoelectron spectroscopic data along with the ab-initio calculations and X-ray diffraction of α-(methylsulfinyl)- and α-(phenylsulfinyl)-acetophenones indicated the predominance of the cis rotamers over the qauche ones.     

A note on random walks with absorbing barriers and sequential Monte Carlo methods

In this article, we consider importance sampling (IS) and sequential Monte Carlo (SMC) methods in the context of one-dimensional random walks with absorbing barriers. In particular, we develop a very precise variance analysis for several IS and SMC procedures. We take advantage of some explicit spectral formulae available for these models to derive sharp and explicit estimates; this provides stability properties of the associated normalized Feynman–Kac semigroups. Our analysis allows one to compare the variance of SMC and IS techniques for these models. The work in this article is one of the few to consider an in-depth analysis of an SMC method for a particular model-type as well as variance comparison of SMC algorithms.     

Radiolabelling of TiO<Subscript>2</Subscript> nanoparticles for radiotracer studies

Industrially manufactured titanium dioxide nanoparticles have been successfully radiolabelled with ⁴⁸V by irradiation with a cyclotron-generated proton beam. Centrifugation tests showed that the ⁴⁸V radiolabels were stably bound within the nanoparticle structure in an aqueous medium, while X-ray diffraction indicated that no major structural modifications to the nanoparticles resulted from the proton irradiation. In vitro tests of the uptake of cold and radiolabelled nanoparticles using the human cell line Calu-3 showed no significant difference in the uptake between both batches of nanoparticles. The uptake was quantified by Inductively Coupled Plasma Mass Spectrometry and high resolution γ-ray spectrometry for cold and radiolabelled nanoparticles, respectively. These preliminary results indicate that alterations to the nanoparticles’ properties introduced by proton bombardment can be controlled to a sufficient extent that their further use as radiotracers for biological investigations can be envisaged and elaborated.     

Radical Copolymerization of Acrylic Monomers. II Effect of Solvent on Radical Copolymerization of Methyl Methacrylate and Styrene

The influence of various solvents on the copolymerization behavior of methyl methacrylate with styrene has been investigated. In these systems there is a significant solvent effect on both r_S and r_M which may be attributed to changes in the dielectric constant of the solvents used. The calculated relative reactivity of the polystyryl radical towards the methyl methacrylate monomer increases with increasing solvent polarity, whereas the reactivity of poly(methyl methacrylate) radical towards styrene monomer decreases. The results obtained are discussed taking into account the behavior of both monomers in homopolymerization with the same experimental conditions as in copolymerization.     

Poly(3,5‐dichloroaniline) Doped with Different Sulfonic Acids

Poly(3,5‐dichloroaniline) was prepared by chemical oxidation in the presence of various sulfonic acids as doping agent, using potassium permanganate as oxidant. 1‐Naphtalene sulfonic acid, 2‐naphatalene sulphonic acid, 1,5‐naphtalene disulfonic acid, and p‐toluenesulfonic acid were the acids of choice. Infrared and UV‐Vis spectroscopy, utilized to characterize the polymers, revealed that the compounds exist in the emeraldine (conductive) oxidation state. The level of doping, conductivity, and morphology were determined as well. The presence of a sulfonic acid produces a morphological change, from granular to microtubule structures, which is responsible for the strong increase in the conductivity of the polymer.     

Improved In vitro and In vivo Cutaneous Delivery of Protoporphyrin IX from PLGA‐based Nanoparticles

We report the development of d , l lactic co‐glycolic acid) (PLGA)‐based nanoparticles (NPs) for topical delivery of protoporphyrin IX (PpIX), a photosensitizer (PS), in treatments like photodynamic therapy (PDT) of skin cancers. PpIX‐NPs were obtained in ~75.0% yield, encapsulation efficiency of 67.7%, drug content of 50.3 μg mg^?1, average diameter of 290 nm maintained up to 30 days and a zeta potential of 32.3 mV. Sustained in vitro release of PpIX through artificial membranes following Higuchi kinetics was kept up to 10 days. In vitro retentions of PpIX both in stratum corneum (SC) and epidermis + dermis ([EP + D]) were higher from NPs (23.0 and 10.0 times, respectively) compared to control solutions at all times. Quantification of PpIX by extraction, after in vivo skin application of NPs‐PpIX on hairless mice, showed higher retention of the PS both in SC and in [EP + D] (3.0 and 2.0 times, respectively) compared to control solutions. Taken together, the results indicate that NPs are suitable for PpIX encapsulation showing minimal permeation through the skin and a localized effect, characteristics of a potential and promising delivery system for PDT‐associated treatments of skin cancers, photodiagnosis and their off‐label uses.     

A molecularly imprinted polymer for the determination of neopterin

A molecularly imprinted polymer (MIP) for the specific retention of neopterin has been developed. A set of 6 polymers was prepared by radical polymerization under different experimental condition using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as crosslinker, with the aim to understand their influence on the efficiency of the MIP. The performance of each MIP was tested in batch experiments via their binding capacity. The MIP prepared in the presence of nickel ions in dimethylsulfoxide-acetonitrile mixture (P4) exhibited the highest binding capacity for neopterin (260 μmol per gram of polymer). A selectivity study with two other pteridines demonstrated the polymer P4 also to possess the best selectivity.