Microfluorometric detection of catecholamines with multiphoton-excited fluorescence

We demonstrate sensitive spatially resolved detection of physiological chromophores that emit in the ultraviolet (<330 nm). An atypical laser source (a visible wavelength femtosecond optical parametric oscillator), and an unconventional collection geometry (a lensless detector that detects the forward-emitted fluorescence) enable this detection. We report the excitation spectra of the catecholamines dopamine and norepinephrine, together with near-UV emitters serotonin and tryptophan, in the range of 550-595 nm. We estimate the molecular two-photon action cross section of dopamine, norepinephrine, and serotonin to be 1.2 mGM (1 GM, or Goppert Mayor, is equal to 10(-58) m4 s(-1) photon(-1)), 2 mGM, and 43 mGM, respectively, at 560 nm. The sensitivity achieved by this method holds promise for the microscopic imaging of vesicular catecholamines in live cells.     

Mechanical behavior of glass polymer multilayer composites

To identify the best reinforcement condition for development of tough glass polymer multi-layer composites (GPMLC) with high failure strain, two such model composite structures were developed. Soda–lime–silica glasses of two different thicknesses viz (A—1.01 mm and B—1.17 mm) were used as the matrix layers. The A-glass and B-glass based GPMLC samples were prepared by a novel, low pressure lamination technique applied to the alternating planar structure of the matrix and reinforcing phases. These GPMLC materials were fabricated with and without a thin sprayed layer of kerosene, between the glass layer and the reinforcing layer in the interface where; the interface was either epoxy (a thermosetting resin) or polyvinyl butyral (PVB, a thermoplastic resin). The GPMLC samples which exhibited stepped load—displacement behaviour in the most pronounced fashion, had the thermoplastic resin at the interface. Most of these GPMLC samples had a thin layer of kerosene intentionally introduced between the glass layer and the reinforcing polymer layer such that a weak interface is obtained. Fractographic evidence suggested that more of controlled delaminaton cracking occurs in such samples. Apart from the chemical nature of the reinforcing polymer phase, the interfacial layer thickness (h _i ) and the interfacial shear stress ( _xy ) were found out to have significant influence on the specific failure load and the failure stress of the current glass polymer multi-layer composites.     

The role of IAEA in coordinating research and transferring technology in radiation chemistry and processing of polymers

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through technical cooperation (TC) projects. Coordinated research projects encourage research on, and development and practical application of, radiation technology to foster exchange of scientific and technical information. The technical cooperation (TC) programme helps Member States to realize their development priorities through the application of appropriate radiation technology.The IAEA has implemented several coordinated research projects (CRP) recently, including one on-going project, in the field of radiation processing of polymeric materials. The CRPs facilitated the acquisition and dissemination of know-how and technology for controlling of degradation effects in radiation processing of polymers, radiation synthesis of stimuli-responsive membranes, hydrogels and absorbents for separation purposes and the use of radiation processing to prepare biomaterials for applications in medicine.The IAEA extends cooperation to well-known international conferences dealing with radiation technology to facilitate participation of talented scientists from developing MS and building collaborations. The IAEA published technical documents, covering the findings of thematic technical meetings (TM) and coordinated research projects have been an important source of valuable practical information.     

Nanosized bismuth ferrite powder prepared through sonochemical and microemulsion techniques

Two processing routes, namely sonochemical and microemulsion have been exploited to prepare bismuth ferrite powders. Phase pure nanosized BiFeO₃ powders are prepared by sonochemical and microemulsion techniques in the temperature range of 400 °C and at 500 °C which is much lower than that of the conventional preparation methods. The XRD obtained from both cases was likely to be pure bismuth ferrite. Though the microemulsion based powders showed slightly better properties with respect to particle size, surface area, and final density, sonochemically prepared powders may be more acceptable considering the ease of preparation and cost effectiveness.     

A new image binarization method using iterative partitioning

This paper proposes a new method for image binarization that uses an iterative partitioning approach. The proposed method has been tested towards binarization of both document and graphic images. The quantitative comparisons with other standard methods reveal that the proposed approach outperforms existing widely used binarization techniques in terms of accuracy of binarization. The experimental results further establish the superiority of the proposed method, especially for degraded documents and graphic images. The proposed algorithm is suitable for a multi-core processing environment as it can be split into multiple parallel units of executions after the initial partitioning.     

Influence of process parameters on the formation of Silicalite-1 zeolite particles

Silicalite-1 particles with minimum twinning have been synthesized inside the polar core of non-ionic surfactant/co-surfactant-stabilized water-in-oil (w/o) type emulsions at 150° ± 1 °C within a short reaction time of 5 h. The non-ionic surfactants of varying hydrophilic–lipophilic balance (HLB) values, i.e. sorbitan monooleate (Span 80, HLB: 4.3), sorbitan monolaurate (Span 20, HLB: 8.6), polyoxyethylene (4) lauryl ether (Brij 30, HLB: 9.7) and polyoxyethylene sorbitan monooleate (Tween 80, HLB: 15), the cationic surfactant, i.e. cetyl trimethyl ammonium bromide (CTAB), surfactant concentration, co-surfactant, synthesis temperature and time have been found to play significant role in controlling size and characteristics of Silicalite-1. It has been observed that the crystallinity and size of Silicalite-1 can be tailored by adjusting the interactions between the polar surfactant head groups at the w/o interface and the growing crystallographic surfaces (or silicate/TPA ions) in the aqueous medium of the emulsion.     

Thermal stresses in an infinite non-isotropic plate having a penny-shaped crack

Of concern in the paper is the distribution of thermal stresses in the vicinity of a penny-shaped crack in a thick elastic plate made of a non-isotropic material. The problem pertains to the situation where the crack is opened by a prescribed normal pressure and a prescribed heat-flux or a prescribed temperature.     

Anomalous quantum transport through a thin film of varying impurity density with the distance from the film surface

We explore a novel transport phenomenon by studying the effect of disorder on electron transport through a thin film of varying disorder strength with the distance from its surface. A simple tight-binding model is used to describe the film which is attached to two metallic electrodes, where the coupling of this film to the electrodes is treated through the use of Newns-Anderson chemisorption theory. It is found that, in the strong disorder regime the current amplitude through the film increases with the increase of the disorder strength, while it decreases in the weak disorder regime. This strange behavior is completely opposite to that of a conventional disordered system. Our results also predict that the electron transport is significantly influenced by the finite size of the thin film.     

A scheme for finite element analysis of mode I and mixed mode stable crack growth and a case study with AISI 4340 steel

A new scheme for elastic–plastic finite element analysis has been proposed for the study of stable crack growth (SCG) from initiation to instability in both mode I and mixed modes (I and II). The scheme is based on node-release technique and helps to determine the variation of fracture load with crack extension without requiring much computer storage and time. The scheme permits predictions of load variation with load line displacement (LLD), maximum fracture load, crack tip current plastic zone and crack edge profile. In the analysis the condition for crack extension at every stage of the SCG is considered to be governed by CTOA/COD reaching a critical value. The scheme of analysis is different from the ones proposed by earlier investigators. The whole SCG is analysed in a few stages using the ANSYS software and a single discretization. Element arrangement in the discretization is decided from the very beginning; it has a capability of accommodating changes in boundary conditions arising out of crack extension in the later stages. Each stage is analysed afresh ignoring state of stress–strain reached at a material point at the end of the previous stage. Case studies on both mode I and mixed mode presented considering AISI 4340 steel, which is widely used in nuclear power industry, indicate that the SCG through it can be characterized in terms of a single COD or CTOA. Predictions for the initiation and maximum fracture loads in both the cases compare very closely with the experimental data reported. The results presented also include the value of critical COD/CTOA (0.035 mm/0.0875 rad) characterizing the SCG through the steel and show that the initiation load is not significantly affected by crack tip radius up to 0.05 mm.     

Studies on the influence of lanthanum oxide on the sinterability of chromium(III) oxide

The mechanism of sintering in chromium(III) oxide in the presence of varying amounts of lanthanum oxide under firing conditions which simulate a controlled reducing atmosphere, has been investigated. The investigation is based on isothermal shrinkage measurements at different temperatures. The data suggest that the vapour-phase transport mechanism becomes predominant with evidence of a grain-boundary diffusion process.