A Tutorial on Integrating CDS/ISIS Databases with the World Wide Web

With the emergence of Internet, the global connectivity of computers has become a reality. Internet has progressed to provide many user-friendly tools like Gopher, WAIS, WWW etc. for information publishing and access. The WWW, which integrates all other access tools, also provides a very convenient means for publishing and accessing multimedia and hypertext linked documents stored in computers spread across the world. With the emergence of WWW technology, most of the information activities are becoming Web-centric. Once the information is published on the Web, a user can access this information from any part of the world. A Web browser like Netscape or Internet Explorer is used as a common user interface for accessing information/databases. This will greatly relieve a user from learning the search syntax of individual information systems. Libraries are taking advantage of these developments to provide access to their resources on the Web. CDS/ISIS is a very popular bibliographic information management software used in India. In this tutorial we present details of integrating CDS/ISIS with the WWW. A number of tools are now available for making CDS/ISIS database accessible on the Internet/Web. Some of these are 1) the WAIS_ISIS Server. 2) the WWWISIS Server 3) the IQUERY Server. In this tutorial, we have explained in detail the steps involved in providing Web access to an existing CDS/ISIS database using the freely available software, WWWISIS. This software is developed, maintained and distributed by BIREME, the Latin American & Caribbean Centre on Health Sciences Information. WWWISIS acts as a server for CDS/ISIS databases in a WWW client/server environment. It supports functions for searching, formatting and data entry operations over CDS/ISIS databases. WWWISIS is available for various operating systems. We have tested this software on Windows '95, Windows NT and Red Hat Linux release 5.2 (Appolo) Kernel 2. 0. 36 on an i686. The testing was carried out using IISc's main library's OPAC containing more than 80,000 records and Current Contents issues (bibliographic data) containing more than 25,000 records. WWWISIS is fully compatible with CDS/ISIS 3.07 file structure. However, on a system running Unix or its variant, there is no guarantee of this compatibility. It is therefore safe to recreate the master and the inverted files, using utilities provided by BIREME, under Unix environment.

Sizable photocurrent and emission from solid state devices based on CdS nanoparticles

CdS nanoparticles exhibit size dependent optical and electrical properties. We report here the photocurrent and I-V characteristic studies of CdS nanoparticle devices. A sizable short circuit photocurrent was observed in the detection range governed by the size of the clusters. We speculate on the mechanisms leading to the photocurrent and emission in these nanometer scale systems.

Structural characteristics of a giant tropical liana and its mode of canopy spread in an alien environment

To circumvent the practical difficulties in research on tropical rainforest lianas in their natural habitat due to prevailing weather conditions, dense camouflaging vegetation and problems in transporting equipment for experimental investigations, Entada pursaetha DC (syn. Entada scandens Benth., Leguminosae) was grown inside a research campus in a dry subtropical environment. A solitary genet has attained a gigantic size in 17 years, infesting crowns of semi-evergreen trees growing in an area roughly equivalent to 1.6 ha. It has used aerially formed, cable-like stolons for navigating and spreading its canopy across tree gaps. Some of its parts which had remained unseen in its natural habitat due to dense vegetation are described. The attained size of this liana in a climatically different environment raises the question as to why it is restricted to evergreen rainforests. Some research problems for which this liana will be useful are pointed out.

Structural and optical investigation of semiconductor CdSe/CdS core-shell quantum dot thin films

Highly luminescent CdSe/CdS core-shell nanocrystals have been assembled on indium tin oxide (ITO) coated glass substrates using a wet synthesis route. The physical properties of the quantum dots (QD) have been investigated using X-ray diffraction, transmission electron microscopy and optical absorption spectroscopy techniques. These quantum dots showed a strong enhancement in the near band edge absorption. The in situ luminescence behavior has been interpreted in the light of the quantum confinement effect and induced strain in the core-shell structure.

Depth profile composition studies of thin film CdS: Cu,S solar cells using XPS and AES

Surface composition and depth profile studies of hemiplated thin film CdS:CuzS solar cells have been carried out using x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) techniques. These studies indicate that the junction is fairly diffused in the as-prepared cell. However, heat treatment of the cell at 210°C in air relatively sharpens the junction and improves the cell performance. Using the Cu(2p3p)/S(2p) ratio as well as the Cu(LVV)/(LMM) Auger intensity ratio, it can be inferred that the nominal valency of copper in the layers above the junction is Cut and it is essentially in the CUSS form. Copper signals are observed from layers deep down in the cell. These seem to appear mostly from the grain boundary region. From the observed concentration of Cd, Cu and S in these deeper layers and the Cu(LVV)/(LMM) ratio it appears that the signals from copper essentially originate partly from copper in CuS and partly from Cu2t trapped in the lattice. It is significant to note that the nominal valence state of copper changes rather abruptly from Cut to Cuz+ across the junction.

Study of Structural Stability and Electronic Structure of Nonstoichiometric CdS Nano Clusters from First Principles

Structural stability of small sized nonstoichiometric CdS nano clusters between zincblende and wurtzite structures has been investigated using first-principles density functional calculations. Our study shows that the relative stability of these two structures depends sensitively on whether the surface is S-terminated or Cd-terminated. The associated band gap also exhibits non-monotonic behavior as a function of cluster size. Our findings may shed light on contradictory reports of experimentally observed structures of CdS nano clusters found in the literature.

Note: Dynamic point spread function for single and multiphoton fluorescence microscopy

We propose and demonstrate a dynamic point spread function (PSF) for single and multiphoton fluorescence microscopy. The goal is to generate a PSF whose shape and size can be maneuvered from highly localized to elongated one, thereby allowing shallow-to-depth excitation capability during active imaging. The PSF is obtained by utilizing specially designed spatial filter and dynamically altering the filter parameters. We predict potential applications in nanobioimaging and fluorescence microscopy.

Note: Dynamic point spread function for single and multiphoton fluorescence microscopy

We propose and demonstrate a dynamic point spread function (PSF) for single and multiphoton fluorescence microscopy. The goal is to generate a PSF whose shape and size can be maneuvered from highly localized to elongated one, thereby allowing shallow-to-depth excitation capability during active imaging. The PSF is obtained by utilizing specially designed spatial filter and dynamically altering the filter parameters. We predict potential applications in nanobioimaging and fluorescence microscopy.

Surface Ligand Population Controlled Oriented Attachment: A Case of CdS Nanowires

using two types of organic ligands having similar chemical structure but different physical properties and varying their dynamic population at the surface of zinc blende seed nanocrystals, self-assembled zinc blende semicircular-shaped bent nanowires of CdS are synthesized via a colloidal synthetic approach. It is found that the hydrophobic tail interaction of long-chain ligands puts strain on these thin nanowires (< 2 nm diameter) and bend them to some extent, forming strained nanowires.

A Reactive Tabu Search Based Equalizer for Severely Delay-Spread UWB MIMO-ISI Channels

We propose a novel equalizer for ultrawideband (UWB) multiple-input multiple-output (MIMO) channels characterized by severe delay spreads. The proposed equalizer is based on reactive tabu search (RTS), which is a heuristic originally designed to obtain approximate solutions to combinatorial optimization problems. The proposed RTS equalizer is shown to perform increasingly better for increasing number of multipath components (MPC), and achieve near maximum likelihood (ML) performance for large number of MPCs at a much less complexity than that of the ML detector. The proposed RTS equalizer is shown to perform close to within 0.4 dB of single-input multiple-output AWGN performance at 10(-3) uncoded BER on a severely delay-spread UWB MIMO channel with 48 equal-energy MPCs.

Optimization of ion energy spread in inductively coupled plasma source designed for focused ion beam applications

The ion energy distribution of inductively coupled plasma ion source for focused ion beam application is measured using a four grid retarding field energy analyzer. Without using any Faraday shield, ion energy spread is found to be 50 eV or more. Moreover, the ion energy distribution is found to have double peaks showing that the power coupling to the plasma is not purely inductive, but a strong parasitic capacitive coupling is also present. By optimizing the various source parameters and Faraday shield, ion energy distribution having a single peak, well separated from zero energy and with ion energy spread of 4 eV is achieved. A novel plasma chamber, with proper Faraday shield is designed to ignite the plasma at low RF powers which otherwise would require 300-400 W of RF power. Optimization of various parameters of the ion source to achieve ions with very low energy spread and the experimental results are presented in this article. (C) 2010 Elsevier Ltd. All rights reserved.

A microcomputer program to analyze the CD spectrum of proteins and nucleic acids—Use of LOTUS 1-2-3 spread sheet

A user friendly interactive computer program, CIRDIC, is developed which calculates the molar ellipticity and molar circular dichroic absorption coefficients from the CD spectrum. This, in combination with LOTUS 1-2-3 spread sheet, will give the spectra of above parameters vs wavelength. The code is implemented in MicroSoft FORTRAN 77 which runs on any IBM compatible PC under MSDOS environment.

Size-Dependent Tuning of Mn2+ d Emission in Mn2+-Doped CdS Nanocrystals: Bulk vs Surface

We show that the characteristic Mn2+ d emission color from Mn2+-doped CdS nanocrystals can be tuned over as much as 40 nm, in contrast to what should be expected from such a nearly localized d-d transition. This is achieved surprisingly by a fine-tuning of the host particle diameter from 1.9 to 2.6 nm, thereby changing the overall emission color from red to yellow. Systematic experiments in conjunction with state-of-the-art ab initio calculations with full geometry optimization establish that Mn2+ ions residing at surface/subsurface regions have a distorted tetrahedral coordination resulting in a larger ligand field splitting. Consequently, these near-surface Mn2+ species exhibit a lower Mn2+ d emission energy, compared to those residing at the core of the nanocrystal with an undisturbed tetrahedral coordination. The origin of the tunability of the observed Mn2+ emission is the variation of emission contributions arising from Mn2+ doped at the core, subsurface, and surface of the host. Our findings provide a unique and easy method to identify the location of an emitting Mn2+ ion in the nanocrystal, which would be otherwise very difficult to decipher.

Interaction of Sesbania mosaic virus movement protein with the coat protein - implications for viral spread

Sesbania mosaic virus (SeMV) is a single-stranded positive-sense RNA plant virus belonging to the genus Sobemovirus. The movement protein (MP) encoded by SeMV ORF1 showed no significant sequence similarity with MPs of other genera, but showed 32% identity with the MP of Southern bean mosaic virus within the Sobemovirus genus. With a view to understanding the mechanism of cell-to-cell movement in sobemoviruses, the SeMV MP gene was cloned, over-expressed in Escherichia coli and purified. Interaction of the recombinant MP with the native virus (NV) was investigated by ELISA and pull-down assays. It was observed that SeMV MP interacted with NV in a concentration- and pH-dependent manner. Analysis of N- and C-terminal deletion mutants of the MP showed that SeMV MP interacts with the NV through the N- terminal 49 amino acid segment. Yeast two-hybrid assays confirmed the in vitro observations, and suggested that SeMV might belong to the class of viruses that require MP and NV/coat protein for cell-to-cell movement.