Harmonic phase-dispersion microscope with a Mach-Zehnder interferometer

Harmonic phase-dispersion microscopy (PDM) is a new imaging technique in which contrast is provided by differences in refractive index at two harmonically related wavelengths. We report a new configuration of the harmonic phase-dispersion microscope in a Mach-Zehnder geometry as an instrument for imaging biological samples. Several improvements on the earlier design are demonstrated, including a single-pass configuration and acousto-optic modulators for generating the heterodyne signals without mechanical arm scanning. We demonstrate quantitative phase-dispersion images of test structures and biological samples.     

Remarks on some aspects of language structure and their relevance to pattern analysis

Some specific aspects of language structure are examined in detail in the context of pattern analysis. In particular, a transformational grammar is constructed for a class of patterns, following the linguistic formulation very closely, by taking a simple example and working it out in detail. Many of the characteristics of the transformational grammars of linguists show up even in this simple example. The need for looking for grammars of different styles and the problem of making meaningful assignment of probabilities to sentences in the context of transformational grammars have also been briefly discussed.     

Wireless Aspects of Telehealth

Telehealth is the use of electronic information and communication technology to deliver health and medical information and services over large and small distances. Broadband wireless services available today, along with more powerful and convenient handheld devices, will enable a transformational change in health management and healthcare with the introduction of real-time monitoring and timely responses to a wide array of patient needs. Further, a network of low-cost sensors and wireless systems help in creating constantly vigilant and pervasive monitoring capability at home and at work. This paper addresses recent efforts in this growing field, including standards, system architectures, propagation models, and lower layer protocols for body area networks. The paper also suggests the use of cooperative transmission-based strategies for such wireless topologies.     

Can variation in durum wheat pasta protein and starch composition affect in vitro starch hydrolysis?

Pasta was prepared with modifications designed to alter its rate of digestion, including altering the ratio of A- to B-granules, incorporating higher amylose content, and varying the glutenin:gliadin ratio and HMW:LMW glutenin subunit ratio. The effects of these modifications were investigated using an in vitro hydrolysis method. A significant reduction in parameters related to glycaemic index was established for high amylose pastas and pastas with 40% B-granule composition, while most other modifications increased the rate of starch hydrolysis. All effects observed were small in comparison to the effect on glycaemic index previously obtained by addition of soluble fibres.     

Fretting fatigue studies of titanium nitride-coated biomedical titanium alloys

Fretting fatigue is an adhesive wear mechanism caused by repetitive tangential micro-oscillation between two contacting materials pressed together under cyclic load. Bioimplants, such as hip joints and bone plates, are prone to undergo fretting fatigue failures during their service within the body. This article presents the fretting fatigue damage characterization of physical vapor deposition (PVD) TiN-coated biomedical titanium alloys (Ti-6Al-4V and Ti-6Al-7Nb) subjected to cyclic loads. The PVD TiN layer delayed the damage because of superior tribological properties compared with uncoated alloys. Delamination and abrasive wear damage of TiN at contact caused failure of the alloy. Friction coefficient curves of the PVD TiN-coated pair showed an irregular pattern caused by the influence of wear particulates and Ringer fluid at the contact.     

Design and material analysis for prototyping of four arm mechanical microgripper with self-locking and anti-slipping capability

Microsystem Technologies - In this work, a mechanically actuated microgripper is designed with the COMSOL Multiphysics and its analysis is discussed. The mechanical microgripper is having a...     

Rapid Synthesis of High Surface Area Imine-Linked 2D Covalent Organic Frameworks by Avoiding Pore Collapse During Isolation

Imine-linked 2D covalent organic frameworks (COFs) form more rapidly than previously reported under Brønsted acid-catalyzed conditions, showing signs of crystallinity within a few minutes, and maximum crystallinity within hours. These observations contrast with the multiday reaction times typically employed under these conditions. In addition, vacuum activation, which is often used to isolate COF materials significantly erodes the crystallinity and surface area of the several isolated materials, as measured by N₂ sorption and X-ray diffraction. This loss of material quality during isolation for many networks has historically obscured otherwise effective polymerization conditions. The influence of the activation procedure is characterized in detail for three COFs, with the commonly used 1,3,5-tris(4-aminophenyl)benzene-terephthaldehyde network (TAPB-PDA COF), the most prone to pore collapse. When the networks are activated carefully, rapid COF formation is general for all five of the imine-linked 2D COFs studied, with all exhibiting excellent crystallinity and surface areas, including the highest surface areas reported to date for three materials. Furthermore, to simplify the workup of COF materials, a simple nitrogen flow method provides high-quality materials without the need for specialized equipment. These insights have important implications for studying and understanding how 2D COFs form.     

Low sintering effect on structural,electrical and magnetic properties of rare-earth metal ion Er3+-substituted nickel–zinc spinal ferrites

Journal of Materials Science: Materials in Electronics - The nano-crystalline particles of erbium-substituted Ni–Zn ferrites with compositional formula Ni0.7Zn0.3ErxFe2?xO4...     

Modelling of Chevron electrothermal actuator and its performance analysis

Microsystem Technologies - In this work, a Chevron electrothermal actuator is designed and its analytical model is developed. Chevron actuator works on the principle of Joules heating effect and...