Inference on superimposed subcritical Galton-Watson processes with immigration

Summary In this paper we consider the superimposed processZ generated by two independent subcritical Galton-Watson processesX ₁ andX ₂, with immigration, by the relationZ=X ₁ +X ₂. The seemingly second order autoregressive relation, that is identified inZ, is exploted towards proposing CAN estimators for the parameters ofZ,X ₁ andX ₂, based on only a partial realisation ofZ, using time series techniques. The results of this paper are motivated by a time series approach for studying specific branching processes due to Venkataraman (1982,Adv. Appl. Prob.,14, 1–20).     

Ditolyldithiophosphato derivatives of phosphorus(III) and phosphorus(V)

O,O′-Ditolylphosphorodithioates of phosphorus(III), [(o-, m-, or p-CH₃C₆H₄O)₂PS₂] _n PCl_3−n , and phosphorus(V), [(o-, m-, or p-CH₃C₆H₄O)₂-PS₂] _n POCl_3−n , (n = 1, 2, and 3) were isolated as colorless viscous liquids by the reaction of PCl₃ and POCl₃ with sodium ditolylphosphorodithioate, (o-, m-, or p-CH₃C₆H₄O)₂PS₂Na, in 1:1, 1:2, and 1:3 molar ratios in toluene. These compounds were characterized by elemental analyses, molecular weight measurements, IR, and NMR (¹H, ³¹P, and ¹³C) spectroscopic studies, which indicated a less common monodentate linkage of dithiophosphate moieties in both phosphorus(III) and phosphorus(V) derivatives leading to a tetrahedral geometry around the phosphorus atom.     

Fusion splicing of heavy metal fluoride glass optical fibres

Heavy metal fluoride (HMF) glass optical fibres were spliced by fusing the two ends of fibres using a DC arc. An average optical loss of 0.08 dB per splice and strengths of up to 600 MPa were achieved for fusion splices using an inert gas purge during splicing. Estimates are made to determine the feasibility of achieving a splice loss of 0.005 dB for single-mode (HMF) fibres.<>     

Parametric study of cylindrical and spherical dust ion acoustic shock waves with two temperature electrons in dusty plasma relevant to Saturn's E ring

We have performed numerical analysis of the one-dimensional dynamics of the cylindrical/spherical dust ion acoustic shock waves in unmagnetized dusty plasma consisting of positive ions, immobile dust particles, and nonextensive distributed cold and hot electrons. A multiple-scale expansion method is used to derive Burgers Equation (BE) and modified Burgers equation (MBE) by including higher order nonlinearity. The basic characteristics of the shock waves have been analysed numerically and graphically for different physical parameters relevant to Saturn' E ring through 2D figures. The parametric dependence of dust ion acoustic shock waves on some plasma parameters nonextensive index, density, and temperature of cold and hot electrons, concentration of dust particles, thermal effects and kinematic viscosity of ions is explored. Furthermore, it is found that the nonplanar geometry effects have an important impact on the establishment of shock waves. The amplitude of the wave decreases faster as one departs away from the axis of the cylinder or centre of the sphere. Such decaying behaviour continues as time progresses. It is also found that an increasing dust concentration decreases the amplitude of the dust ion acoustic shock waves.     

Phosphosulfonic acid‐catalyzed green synthesis and bioassay of α‐aryl‐α′‐1,3,4‐thiadiazolyl aminophosphonates

A series of new α‐aminophosphonates containing 1,3,4‐thiadiazole moiety (4a–l) were synthesized via a simple, efficient, and one‐pot three‐component Kabachnik–Fields reaction of 2‐amino‐5‐ethyl‐1,3,4‐thiadiazole with various aryl/heteroaryl aldehydes and diethylphosphite under solvent‐free microwave irradiation conditions using phosphosulfonic acid, as a reusable and heterogeneous solid acid catalyst. All the title compounds were screened for radical scavenging activity by DPPH and H₂O₂ methods, and antimicrobial activity against bacteria (Gram‐positive and Gram‐negative) and fungi using the disc diffusion technique. They exhibited potent in vitro antioxidant and moderate antimicrobial activity.     

Stereodivergent approach to Alzheimer's therapeutic agent (R)-(−) and (S)-(+)-arundic acid employing chiral 4-pentenol derivatives as building blocks

An efficient stereodivergent total synthesis of anti-Alzheimer agent (R)-(?) and (S)-(+)-arundic acid has been achieved from both chiral and nonchiral materials. This strategy features an efficient approach to separable diastereomeric C-2 chiral 4-pentenol intermediates employing proline catalysed asymmetric α-aminooxylation and [3,3] sigmatropic Claisen rearrangement are the highlights of present synthesis.     

A convenient new and efficient commercial synthetic route for dasatinib (Sprycel®)

A new and efficient synthetic route for dual-Src/Abl kinase inhibitor dasatinib (Sprycel®), an anticancer drug, is described. This commercially viable process yields dasatinib monohydrate free of potential impurities with consistent yield of 68% in route A and 61% in route B with HPLC purity >99.80% over four stages.     

High resolution detection of high mass proteins up to 80,000 Da via multifunctional CdS quantum dots in laser desorption/ionization mass spectrometry

CdS quantum dots (∼5 nm) are used as multifunctional nanoprobes as an effective matrix for large proteins, peptides and as affinity probes for the enrichment of tryptic digest proteins (lysozyme, myoglobin and cytochrome c) in laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS). The use of CdS quantum dots (CdS QDs) as the matrix allows acquisition of high resolution LDI mass spectra for large proteins (5000-80,000 Da). The enhancement of mass resolution is especially notable for large proteins such as BSA, HSA and transferrin (34-49 times) when compared with those obtained by using SA as the matrix. This technique demonstrates the potentiality of LDI-TOF-MS as an appropriate analytical tool for the analysis of high-molecular-weight biomolecules with high mass resolution. In addition, CdS QDs are also used as matrices for background-free detection of small biomolecules (peptides) and as affinity probes for the enrichment of tryptic digest proteins in LDI-TOF-MS.     

Surface modified silver selinide nanoparticles as extracting probes to improve peptide/protein detection via nanoparticles-based liquid phase microextraction coupled with MALDI mass spectrometry

We report the first use of functionalized Ag₂Se nanoparticles (NPs) as effective extracting probes for NPs-based liquid-phase microextraction (NPs-LPME) to analyze hydrophobic peptides and proteins from biological samples (urine and plasma) and soybean in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Surface modified functional groups such as octadecanethiol (ODT) and 11-mercaptoundecanoic acid (MUA) on Ag₂Se NPs were found to play an important role for efficient extraction of peptides and proteins from test samples through hydrophobic interactions. The peptides can be efficiently extracted using functionalized Ag₂Se NPs as extracting probes in the presence of high concentration of matrix interferences such as 4 M urea, 0.5% Triton X-100 and 3% NaCl. Ag₂Se@ODT NPs have shown better extraction efficiency and detection sensitivity for peptides than Ag₂Se@MUA NPs, bare Ag₂Se NPs and conventional MALDI-MS. The LODs are 20-68 nM for valinomycin and 100-180 nM for gramicidin D using Ag₂Se@ODT NPs-LPME in the MALDI-MS. The current approach is highly sensitive and the target analytes can be effectively isolated without sample loss and efficiently analyzed in MALDI-MS.     

Dissolution of sintered thorium dioxide in phosphoric acid using autoclave and microwave methods with detection by gamma spectrometry

A quantitative and fast method of dissolution of refractory thoria (ThO₂) was developed for the determination of thorium (Th) in a given sample. The dissolution of sintered ThO₂ powder, microspheres and pellets using 88% phosphoric acid was investigated. The conditions of quantitative dissolution of ThO₂ microspheres were optimized by conventional heating in autoclave and also by microwave heating. 100 mg of sintered ThO₂ microspheres were dissolved in 8 g of phosphoric acid in an autoclave, and heating at 170 °C for 3 h, in comparison to 5 g of phosphoric acid by microwave heating (375 W) at 220 °C for 1 h. Dissolution studies on the powder form of sintered ThO₂ were also performed. 1 g of sintered ThO₂ powder could be dissolved in 6.5 g of phosphoric acid in autoclave heating at 170 °C for 1 h. Strong complexing of (PO₄)³⁻ with Th⁴⁺ may be the influencing factor for quantitative dissolution of ThO₂.