Characterization of reduced graphene oxide obtained from vacuum-assisted low-temperature exfoliated graphite

Microsystem Technologies - Graphene consists of sheets of two-dimensional allotrope carbons and is a basic element of graphite. Herein, reduced graphene oxide (rGO) were exfoliated from graphite...     

5 Fluorouracil‐loaded biosynthesised gold nanoparticles for the in vitro treatment of human pancreatic cancer cell

In this study, green synthesis of gold nanoparticles (AuNPs) was performed by a sunlight irradiation method using the Borassus flabellifer fruit extract as a reducing agent. 5‐Fluorouracil (5‐FU)‐loaded GG capped AuNPs (5FU‐G‐AuNPs) was prepared. The nanoparticles was further characterised by UV‐visible spectra, particle size analysis, zeta potential, SAED, HRTEM, and XRD. The MTT assay results showed the suitability 5‐FU‐G‐AuNPs. In this study, 5‐FU‐G‐AuNPs exhibited potential cytotoxic and apoptotic effects on (MiaPaCa‐2) cell line.Inspec keywords: gold, biochemistry, X‐ray diffraction, nanofabrication, biomedical materials, transmission electron microscopy, toxicology, electrokinetic effects, particle size, nanoparticles, cancer, visible spectra, cellular biophysics, ultraviolet spectra, nanomedicine, patient treatment, organic compoundsOther keywords: 5FU‐G‐AuNPs, suitability 5‐FU‐G‐AuNPs, human pancreatic cancer cell, green synthesis, sunlight irradiation method, 5‐Fluorouracil‐loaded GG, in vitro treatment, 5 fluorouracil‐loaded biosynthesised gold nanoparticles, borassus flabellifer fruit extract, reducing agent, UV‐visible spectra, particle size analysis, zeta potential, SAED, HRTEM, XRD, MTT assay, apoptotic effects, cytotoxic effects, MiaPaCa‐2 cell line, Au     

Phaselets of framelets

Phaselets are a set of dyadic wavelets that are related in a particular way such that the associated redundant wavelet transform is nearly shift-invariant. Framelets are a set of functions that generalize the notion of a single dyadic wavelet in the sense that dyadic dilates and translates of these functions form a frame in L/sup 2/(IR). This paper generalizes the notion of phaselets to framelets. Sets of framelets that only differ in their Fourier transform phase are constructed such that the resulting redundant wavelet transform is approximately shift invariant. Explicit constructions of phaselets are given for frames with two and three framelet generators. The results in this paper generalize the construction of Hilbert transform pairs of framelets.     

Development of a Centrifugal Oil Lubricator for Long-Term Lubrication of Spacecraft Attitude Control Systems—Experimental Evaluation

The success of a spacecraft mission depends to a great extent on the performance of the moving mechanical systems. The most common mode of failure in these systems is tribological. Tribological failures occur mainly due to nonavailability of lubricant at the working zone of the bearings as a result of degradation, evaporation, and creep. The life of these moving mechanical systems could be extended if lubricant is replenished by some means. Therefore, to ensure long-term uninterrupted performance of these systems, an efficient lubricant replenishment system is essential. This article describes the development of a novel lubricant supply system that can supply lubricant for more than 30 years at a controlled rate of a few micrograms/hour. Experimental evaluation of the lubricator was carried out under different operating conditions experienced in a spacecraft. The results of the experiments are compared with the theoretical results obtained from the mathematical model and computational fluid dynamics (CFD) simulation. The lowest flow rate obtained was 3.5 μg/h from a lubricator with a flow control orifice diameter of 2.3 μm. The results of the study show that the lubricator can provide a long-term uninterrupted supply of lubricant to the moving mechanical systems for a period of more than 30 years. An outstanding and most promising feature of this lubricator is that the flow rate at various stages of the life can be theoretically predicted using the developed mathematical model and the prediction can be experimentally verified before the system is put into service.     

Identification of a novel structure in heparin generated by sequential oxidative-reductive treatment

Unfractionated heparin is isolated from animal organs, predominantly porcine intestinal mucosa, and goes through an extensive process of purification before it can be used for pharmaceutical purposes. While the structural microheterogeneity of heparin is predominantly biosynthetically imprinted in the Golgi, subsequent steps involved in the purification and manufacture of commercial heparin can lead to the introduction of additional modifications. Postheparin crisis of 2008, it has become increasingly important to identify what additional structural diversity is introduced as a function of the purification process and thus can be determined as being heparin-related, as opposed to being an adulterant or contaminant, e.g., oversulfated chondroitin sulfate. Our study focuses on the identification of a previously unreported structure in heparin that arises due to specific steps used in the manufacturing process. This structure was initially observed as a disaccharide peak in a complete enzymatic digest of heparin, but its presence was later identified in the NMR spectra of intact heparin as well. Structural elucidation experiments involved isolation of this structure and analysis based on multidimensional NMR and liquid chromatography coupled with mass spectrometry (LC-MS). Heparin was also subjected to specific chemical reactions to determine which steps in the manufacturing process are responsible for this novel structure. Our results allowed for the definitive assignment of the structure of this novel process-related modification and enabled an identification of the putative steps in the process that give rise to the structure.     

Flagellar dynamics of a connected chain of active,polar, Brownian particles

We show that active, self-propelled particles that are connected together to form a single chain that is anchored at one end can produce the graceful beating motions of flagella. Changing the boundary condition from a clamp to a pivot at the anchor leads to steadily rotating tight coils. Strong noise in the system disrupts the regularity of the oscillations. We use a combination of detailed numerical simulations, mean-field scaling analysis and first passage time theory to characterize the phase diagram as a function of the filament length, passive elasticity, propulsion force and noise. Our study suggests minimal experimental tests for the onset of oscillations in an active polar chain.     

Polarization-insensitive optical amplifiers in AlInGaAs

We report the theoretical modeling and the fabrication of polarization-insensitive optical amplifiers at 1300 nm in AlInGaAs-InP material system. Gain calculations, using the k.p method, show that the introduction of 0.33% tensile strain into a three-quantum-well structure can achieve gain-matching over a wide energy spectrum. The amplifiers, fabricated and tested, show excellent polarization insensitivity (less than 0.3 dB) at 1280 nm with a gain of 11 dB at 150 mA. Gain-bandwidth needs to be improved by employing antireflection coatings to suppress the facet reflectivity     

Intellectual property rights in computer software: Issues at stake for developing countries

Abstract

Intellectual Property Rights (IPR) have become important in the discourse amongst nations as it may have substantial bearing on the wealth of nations in the future. Computer software is an important component of these new types of property. Since developing countries have some of the factors of production in software and certain developing countries have made significant investments in education, it has become critical to study the impact of IPR on developing countries. In this paper, we investigate IPR in computer software and their implications for developing countries (sometimes with specific reference to India), especially in the context of the GATT/TRIPs agreement that was recently concluded at Marrakesh.     

Valence Charge Fluctuations and Tc Retention in Tl1?xPbxSr1+xLa1?xCuO5?y (0.0 ≤ x ≤0.5) System

Structural and x-ray photoelectron spectroscopy (XPS) studies of the Tl_1–xPb_xSr_1+xLa_1–xCuO_5–y (0.0x0.5) system have been carried out. The unit cell parameters increase with x. Irrespective of x the T_c is retained in this series and the optimum hole concentration (n_h) is maintained for x 0.5. An increase in Tl 4f and O ls binding energy with x suggests a reduction in their oxidation state. Origin of holes is discussed in terms of charge transfer between Tl, Pb and CuO₂ layers.     

Symmetric deformable image registration via optimization of information theoretic measures

The use of information theoretic measures (ITMs) has been steadily growing in image processing, bioinformatics, and pattern classification. Although the ITMs have been extensively used in rigid and affine registration of multi-modal images, their computation and accuracy are critical issues in deformable image registration. Three important aspects of using ITMs in multi-modal deformable image registration are considered in this paper: computation, inverse consistency, and accuracy; a symmetric formulation of the deformable image registration problem through the computation of derivatives and resampling on both source and target images, and sufficient criteria for inverse consistency are presented for the purpose of achieving more accurate registration. The techniques of estimating ITMs are examined and analytical derivatives are derived for carrying out the optimization in a computationally efficient manner. ITMs based on Shannon’s and Renyi’s definitions are considered and compared. The obtained evaluation results via registration functions, and controlled deformable registration of multi-modal digital brain phantom and in vivo magnetic resonance brain images show the improved accuracy and efficiency of the developed formulation. The results also indicate that despite the recent favorable studies towards the use of ITMs based on Renyi’s definitions, these measures are seen not to provide improvements in this type of deformable registration as compared to ITMs based on Shannon’s definitions.