The effect of three-fold astigmatism on measurements of grain boundary volume expansion by high-resolution transmission electron microscopy

In the absence of high-order aberrations, the lattice fringe technique should allow measurement of grain boundary rigid-body displacements to accuracies about an order of magnitude better than the point-to-point resolution of the transmission electron microscope. The three-fold astigmatism, however, introduces shifts of the lattice fringe pattern that depend on the orientation of the lattice relative to the direction of the three-fold astigmatism and thus produces an apparent shift between the two grains bordering the grain boundary. By image simulation of grain boundary model structures, the present paper explores the effect of these extraneous shifts on grain boundary volume expansion measurements. It is found that the shifts depend, among others, on zone axis direction and the magnitude of the lattice parameter. For many grain boundaries of interest, three-fold astigmatism correction to better than 100 nm appears necessary to achieve the desired accuracies.     

Supercritical carbon dioxide extraction of onion oleoresin

Supercritical carbon dioxide (SC-CO₂) extraction on a laboratory-scale, was applied to produce oleoresin from dried onion (Allium cepa L). The goal of this work was to determine the optimal conditions of extraction for producing oleoresin with the highest yield and the best quality. A polynomial model was developed on the data. The square of correlation coefficient was R²=0·9022 (at P⩽0·05). The statistical analysis showed that the extraction pressure, temperature, and time have significant influence on the yield of the oleoresin. Increasing these parameters resulted in an increase in the yield. Maximum yield was obtained when the extraction pressure and temperature were above 350 bar and 57°C, respectively. At the lowest pressure (150 bar) applied the highest concentration of sulphur was produced in the oleoresin. The concentration of sulphur increased as a function of temperature when the pressure was maintained at 300 and 400 bar. The composition of volatile compounds of oleoresin differed from that of distilled onion oil. © 1998 SCI.     

Role and Regulation of Mechanotransductive HIF-1α Stabilisation in Periodontal Ligament Fibroblasts

Orthodontic tooth movement (OTM) creates compressive and tensile strain in the periodontal ligament, causing circulation disorders. Hypoxia-inducible factor 1α (HIF-1α) has been shown to be primarily stabilised by compression, but not hypoxia in periodontal ligament fibroblasts (PDLF) during mechanical strain, which are key regulators of OTM. This study aimed to elucidate the role of heparan sulfate integrin interaction and downstream kinase phosphorylation for HIF-1α stabilisation under compressive and tensile strain and to which extent downstream synthesis of VEGF and prostaglandins is HIF-1α-dependent in a model of simulated OTM in PDLF. PDLF were subjected to compressive or tensile strain for 48 h. In various setups HIF-1α was experimentally stabilised (DMOG) or destabilised (YC-1) and mechanotransduction was inhibited by surfen and genistein. We found that HIF-1α was not stabilised by tensile, but rather by compressive strain. HIF-1α stabilisation had an inductive effect on prostaglandin and VEGF synthesis. As expected, HIF-1α destabilisation reduced VEGF expression, whereas prostaglandin synthesis was increased. Inhibition of integrin mechanotransduction via surfen or genistein prevented stabilisation of HIF-1α. A decrease in VEGF expression was observed, but not in prostaglandin synthesis. Stabilisation of HIF-1α via integrin mechanotransduction and downstream phosphorylation of kinases seems to be essential for the induction of VEGF, but not prostaglandin synthesis by PDLF during compressive (but not tensile) orthodontic strain.     

Dimensionality and clustering in the semantic network of patients with Alzheimer's disease.

Investigated the organization of semantic memory in patients with Alzheimer's disease (AD) with a triadic comparison task. A multidimensional scaling statistic was used to analyze proximity data and to generate 3-dimensional cognitive maps that were then compared by a discriminant function analysis. Results suggest that the structure of semantic memory in AD Ss differs from that of elderly normal controls (NCs) in 2 ways. First, AD Ss are less consistent in using the attributes (predation, domesticity, and size) of concepts. Second, AD Ss focus primarily on concrete perceptual information (size), whereas NCs stress abstract conceptual knowledge (domesticity). Results are consistent with the notion that AD is characterized by a breakdown in the structure of semantic knowledge. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Local and global mappings of topology representing networks

As data analysis tasks often have to deal with complex data structures, the nonlinear dimensionality reduction methods play an important role in exploratory data analysis. In the literature a number of nonlinear dimensionality reduction techniques have been proposed (e.g. Sammon mapping, Locally Linear Embedding). These techniques attempt to preserve either the local or the global geometry of the original data, and they perform metric or non-metric dimensionality reduction. Nevertheless, it is difficult to apply most of them to large data sets. There is a need for new algorithms that are able to combine vector quantisation and mapping methods in order to visualise the data structure in a low-dimensional vector space. In this paper we define a new class of algorithms to quantify and disclose the data structure, that are based on the topology representing networks and apply different mapping methods to the low-dimensional visualisation. Not only existing methods are combined for that purpose but also a novel group of mapping methods (Topology Representing Network Map) are introduced as a part of this class. Topology Representing Network Maps utilise the main benefits of the topology representing networks and of the multidimensional scaling methods to disclose the real structure of the data set under study. To determine the main properties of the topology representing network based mapping methods, a detailed analysis of classical benchmark examples (Wine and Optical Recognition of Handwritten Digits data set) is presented.     

Simulation of thermal stress in reinforced concrete at early ages with a simplified model

This paper is primarily concerned with stresses and cracking in reinforced concrete caused by restrained thermal deformations during the hydration process. Simulation of thermal stresses and crack occurrence is carried out with a simplified model. By validation against tests, it is shown that the simple, one-dimensional model gives a reasonable estimate of the thermal stress development. The model is based on a few input parameters like temperature history, stiffness development and tensile strength development. By means of a parametric investigation, the age-dependent stiffness of the concrete and the temperature history are identified as the decisive material characteristics regarding the thermal stress level. It is also found that the reinforcement has no effect prior to cracking but a clear crack redistributing role in the post-cracking state.     

Irrigation, Productivity and Poverty Linkages in Irrigation Systems in Java, Indonesia

This paper analyzes irrigation-poverty linkages, and determines how and to what extent irrigation contributes to poverty alleviation, and whether there are any spatial patterns in poverty in irrigation systems. It also identifies conditions under which irrigation has greater anti-poverty impacts. The analysis is based on primary data collected during the 2000--2001 agricultural year, from four selected irrigation systems and rainfed areas in Java. The results indicate that irrigation has significant poverty reducing impacts. Poverty varies across irrigation systems and across locations within the systems. In general, crop productivity is relatively higher and poverty is lower in middle parts of the systems compared to head and tail parts. Further, locational differences in poverty are more pronounced in larger systems where locational inequities in water distribution and productivity differences are also high. Crop productivity, the size of landholdings and location of households are important determinants of poverty, in addition to demographic factors such as family size. The smaller the systems with well managed infrastructure, relatively equitable water distribution and diversified cropping patterns supported with market infrastructure, the greater the poverty reducing impacts of irrigation. Overall, the study findings suggest that improving the performance of irrigation systems by enhancing land and water productivity, diversifying cropping patterns and improving water distribution across locations would help reduce poverty in presently low productivity-high poverty parts of the systems.     

Evaluation of tRNA intergenic spacer length polymorphism analysis as a molecular method for species identification of streptococcal isolates from bovine mastitis

Sixty-nine bovine mastitis streptococci belonging to the species Str. agalactiae (n = 13), Str. dysgalactiae (n = 16), Str. canis (n = 22), Str. uberis (n = 20) and Str. parauberis (n = 4) and six reference strains of the five streptococcal species were examined for their tRNA gene intergenic length polymorphism (tDNA-ILP) fingerprint pattern. Epidemiologically unrelated isolates from bovine mastitis cases were selected by macrorestriction analysis with pulsed-field gel electrophoresis (PFGE). Their results were compared with those obtained from biochemical and serological studies and with those obtained by PCR-mediated identification amplifying species-specific gene segments of the five streptococcal species. According to the present results tDNA-ILP allowed a correct identification of all Str. agalactiae, Str. uberis and Str. parauberis strains investigated also including the reference strains of each species showing species-specific banding pattern. However, all Str. dysgalactiae ssp. dysgalactiae and all Str. canis strains appeared with an undistinguishable pattern which did not allow an identification of the species.     

CO2waveguide laser with Fox-Smith mode selector

Frequency tuning of a line tunable CO2wavegnide laser by use of a Fox-Smith mode selector is reported. The laser delivers output powers up to 2 W with a tuning range of 500 MHz. Design criteria for a laser with higher output power and larger tunability are obtained from an experimental investigation of the mode selector losses and comparison with the theory.     

Experimental determination of the energy dependence of defect production

A knowledge of primary damage production as a function of recoil energy is essential for predicting defect production in radiation environments of practical interest. The damage function $\text{ν(T)}$, i.e., the number of Frenkel pairs as a function of recoil energy, is determined for Cu from electron and ion damage-rate measurements. $\text{ν(T)}$ shows a plateau at $\text{ν = 0.54}$ which extends up to ~ $\text{7T}{}_{\mathrm{d}}{}^{\min }$. Therefore, simple damage models, such as the modified Kinchin-Pease expression, are strongly deficient, not only at high recoil energies where stimulated recombination in cascades reduces defect production, but also in the single displacement regime. As a consequence, no simple relation between $\text{T}{}_{\mathrm{d}}{}^{\min }$ and $\text{T}{}_{\mathrm{d}}{}^{\mathrm{av}}$ is expected to exist. A procedure is suggested which uses anisotropy measurements in combination with polycrystal electron and ion irradiations to construct absolute damage functions in metals.