A generalized phase field multiscale finite element method for brittle fracture

A generalized multiscale finite element method is introduced to address the computationally taxing problem of elastic fracture across scales. Crack propagation is accounted for at the microscale utilizing phase field theory. Both the displacement-based equilibrium equations and phase field state equations at the microscale are mapped on a coarser scale. The latter is defined by a set of multinode coarse elements, where solution of the governing equations is performed. Mapping is achieved by employing a set of numerically derived multiscale shape functions. A set of representative benchmark tests is used to verify the proposed procedure and assess its performance in terms of accuracy and efficiency compared with the standard phase field finite element implementation.     

Cutting with coated tools: Coating technologies,characterization methods and performance optimization

Coated tools constitute the majority of the tools applied in material removal processes, rendering the employment of uncoated ones as an exception. A broad growing market of coated cutting tools has been developed. Moreover, numerous material- and manufacturing-engineers have joint their expertise, aiming at developing coatings meeting the needs for processing the most difficult-to-cut materials at the most extreme cutting conditions. The emerging of new workpiece, tool and film materials, the evolution of sophisticated coatings’ characterization methods and the continuous need for higher productivity rates, maintain vivid the industrial and scientific interest for further advancing this field.     

Development and characterization of oligonucleotide-tagged dye-encapsulating EPC/DPPG liposomes

Liposomes applications in health care include meanly their ability to carry drugs and genes inside the human body for therapeutic purposes. Nevertheless their applicability can extend far beyond and could be used as analytical tools in order to perform rapid, low-cost, sensitive and specific analyses. Their physical characteristics, such as large internal volume and extended surface area, render them ideal for these applications and specifically for improving the specificity and sensitivity of the analytical assay. The purpose of this study was to develop a simple, stable and low-cost oligonucleotide-tagged liposomal formulation consisting of EggPC and DPPG with a simple to synthesize thiol-reactive conjugate (Mal-SA) incorporated into the lipid bilayer of liposomes. The prepared liposomes, having also the water soluble dye Sulforhodamine B encapsulated in their inner cavity, were characterized in terms of their physicochemical (size, size distribution, zeta-potential, lipid content) and mechanical (morphology, rigidity) properties. The results showed that the final liposomal formulation could be used in the future as analytical tool for detecting pathogen strains of microorganism in biological milieu.     

The application of two dimensional compression schemes to computer graphic display systems

Various picture compression schemes are proposed which achieve a reduction in the capacity of refresh storage by exploiting the redundancy in computer graphic pictures. Many different types of compression scheme have previously been considered, particularly for facsimile transmission of black and white pictures. This paper studies a compression scheme which takes into account the two dimensional nature of computer graphic pictures and which are digitized into more than two grey levels. A practical implementation of the method is also proposed for a real time computer display system.     

Implementation of structured display files in interactive colour graphics

This paper discusses the various types of data structure used in computers, analyses their advantages and disadvantages, and assesses their suitability for use in microprocessor-based interactive computer graphics. Its main purpose is to define a display file structure which introduces levels of hierarchy amongst the elements of computer-generated images. The use of structured display files arises from the need to assist the user of an interactive system by supplying the software tools required to allow easy manipulation of the image contents.     

Calculation of the efficiency of polarization-insensitive surface-stabilized ferroelectric liquid-crystal diffraction gratings

A rigorous analysis is presented of the diffraction efficiency of a polarization-insensitive surface-stabilized ferroelectric liquid-crystal (SSFLC) phase grating, taking full account of the internal structure of the ferroelectric liquid-crystal layer. When no field is applied, the twisted director profile in the relaxed state gives an optimum diffraction efficiency for a device thickness between the half-wave-plate and the full-wave-plate conditions. The influence of the magnitude of the spontaneous polarization and applied ac fields are investigated, and it is shown that the diffraction efficiency of a binary SSFLC phase grating can be strongly enhanced with the technique of ac stabilization.     

A microprocessor-based still frame capturing system

This paper describes the design and implementation of a low cost image capturing system. The basic feature of the design is the massive reduction of the storage requirement in comparison with a fully buffered system. This has been accomplished by effecting a compromise between the amount of high speed storage and the time required to store all or part of a digitized frame, defined as 512 scan lines, each containing 512 picture elements in the format of eight-bit words. The system can be used for the transmission of pictures, texts or documents, where the need for storing pictorial data before transmission can be totally eliminated. It can also be employed as a low cost input technique for a digital image processing system where the required image can be stored in a computer memory and undergo various image processing operations.     

Compression defects in different reconstructions from phase-shifting digital holographic data

Three principal strategies for the compression of phase-shifting digital holograms (interferogram domain-, hologram domain-, and reconstruction domain-based strategies) are reviewed and their effects in the reconstruction domain are investigated. Images of the reconstructions are provided to visually compare the performances of the methods. In addition to single reconstructions the compression effects on different depth reconstructions and reconstructions corresponding to different viewing angles are investigated so that a range of the 3D aspects of the holograms may be considered. Although comparable at low compression rates, it is found that depth and perspective information is degraded in different ways with the different techniques at high compression rates. A hologram of an object with sufficient details at different depths is used so that both parallax and depth effects can be illustrated.     

Reflectivity properties of an anisotropic slab waveguide with isolated substrate

The scattering properties for both TE and TM modes of an abruptly ended two-layered slab waveguide with anisotropic core and isolated substrate are examined by an improved iteration technique, which is based on the integral equation method with accelerating parameters. The relative dielectric constants of the core for the three Cartesian directions are considered to be different, but cases with isotropic core are also considered. The electric field distribution on the terminal plane and the reflection coefficients of the dominant TE and TM guided modes, as well as the near-field distribution and the far-field radiation pattern, are computed, while numerical results are presented for several cases of the core anisotropy.     

The Discovery of a Highly Selective 5,6,7,8‐Tetrahydrobenzo[4,5]thieno[2,3‐d]pyrimidin‐4(3H)‐one SIRT2 Inhibitor that is Neuroprotective in an in vitro Parkinson’s Disease Model

Sirtuins, NAD⁺‐dependent histone deacetylases (HDACs), have recently emerged as potential therapeutic targets for the treatment of a variety of diseases. The discovery of potent and isoform‐selective inhibitors of this enzyme family should provide chemical tools to help determine the roles of these targets and validate their therapeutic value. Herein, we report the discovery of a novel class of highly selective SIRT2 inhibitors, identified by pharmacophore screening. We report the identification and validation of 3‐((2‐methoxynaphthalen‐1‐yl)methyl)‐7‐((pyridin‐3‐ylmethyl)amino)‐5,6,7,8‐tetrahydrobenzo[4,5]thieno[2,3‐d]pyrimidin‐4(3H)‐one (ICL‐SIRT078), a substrate‐competitive SIRT2 inhibitor with a K_i value of 0.62±0.15 μM and more than 50‐fold selectivity against SIRT1, 3 and 5. Treatment of MCF‐7 breast cancer cells with ICL‐SIRT078 results in hyperacetylation of α‐tubulin, an established SIRT2 biomarker, at doses comparable with the biochemical IC₅₀ data, while suppressing MCF‐7 proliferation at higher concentrations. In concordance with the recent reports that suggest SIRT2 inhibition is a potential strategy for the treatment of Parkinson’s disease, we find that compound ICL‐SIRT078 has a significant neuroprotective effect in a lactacystin‐induced model of Parkinsonian neuronal cell death in the N27 cell line. These results encourage further investigation into the effects of ICL‐SIRT078, or an optimised derivative thereof, as a candidate neuroprotective agent in in vivo models of Parkinson’s disease.