Microstructural investigations of PBT/nylon 6,6 composites

The microstructure of composites made from blends of poly(p-phenylene benzobisthiazole) [PBT] and nylon 6,6 has been investigated with wide-angle X-ray diffraction, selected area electron diffraction, and small-angle X-ray scattering techniques. The composite samples investigated were spun in both fiber and film forms dilute solutions of methane sulfonic acid. The structure of the composites was found to be a microfibrillar network of PBT in a matrix of partially crystalline nylon 6,6. The diameters of the PBT microfibrils were in the range of 30 to 70 Å.     

Microchemistry and Mechanisms of Adherence in Steel/Enamel Interfaces

The microchemistry of steel/enamel interfaces was investigated, on a nearly atomic scale, by means of X-ray photoelectron spectroscopy. Experimental evidence is given that good adherence is characterized by a fully reacted iron silicate phase, which produces a local chemical continuity between steel and enamel, whereas bad adherence is associated with a heterogeneous mixture of an iron silicate phase plus unreacted FeO.     

Radiographical assessment of interphalangeal rotation in the evaluation of equine digital conformation

The purpose of this double-blind study was to evaluate the effectiveness of a commercially available fluoride lacquer (Bifluorid 12) containing CaF2 (6%) and NaF (6%) in reducing dentine hypersensitivity. A fluoride lacquer containing only NaF (6%) served as a control. Twenty-five adult patients complaining about at least two hypersensitive teeth participated in this study. In each patient and at each appointment, one tooth was treated with Bifluorid 12, while the other was treated with the control substance. Sensitivity levels were determined before and after the application of each lacquer at baseline as well as at 1, 2 and 3 weeks after the start of study. The final evaluation of hypersensitivity was performed at 4 weeks, and follow-ups were undertaken at 6 and 12 months. A reproducible air blast stimulus and a visual analogue scale were used for evaluation. Results demonstrated a distinct reduction of hypersensitivity after 1, 2 and 3 weeks in the Bifluorid 12 group. Initially, no obvious effects could be observed in the control group. However, a clear alleviation could be observed after 2 and 3 weeks with the control. After 4 weeks, the overall sensitivity scores were comparably low, without any significant differences between the two fluoride lacquers. In both groups, the effects of treatment were seen over the 12-month observation period. Bifluorid 12 was considered at least comparable to the control. It is concluded from this study that Bifluorid 12 is effective in the initial reduction of dentine hypersensitivity. The combination of CaF2/NaF can be recommended for clinical use.     

Can a local histogram really map texture information?

This paper presents a methodology to extract information from a set of r labeled counts with constant sum N called an “Organ Pipe Diagram (OPD)”. A histogram is a particular OPD with an order relation on its count labels.As an application of this methodology, if a global image of radiometries is scanned by a window, a “module” value and a “state” can be defined for the local histogram. The corresponding maps of modules and states yield a useful local spatial information closely related to texture. The methodology is interesting in itself, as it shows how a geometry can be built-up from a set of labeled counts whose space of definition is shown to be a simplex.     

The influence of layered compounds on the properties of starch/layered compound composites

Glycerol‐plasticized starch films were modified by addition of various layered compounds as fillers, two being of natural origin (kaolinite, a neutral mineral clay, and hectorite, a cationic exchanger mineral clay) and two synthetic (layered double hydroxide, LDH, an anionic exchanger, and brucite, having a neutral structure). The effects of the filler type and the plasticizer were analyzed by X‐ray diffraction, dynamic mechanical analysis and thermogravimetry. The storage modulus was higher for kaolinite > brucite > hectorite than for LDH starch composites. However, only the hectorite filler presented a shift of the interplanar basal distance to higher values, which represents the intercalation of glycerol molecules between the clay layers. The glycerol intercalation is minimized in plasticized–oxidized starch films where the oxidized starch chains are preferentially intercalated. Copyright © 2003 Society of Chemical Industry     

M&M's: Building Binary Software Components for Supporting Mobile-Agent Enabled Applications

Mobile Agents provide a new promising paradigm for developing distributed applications. Nevertheless, although the basic concept has been around for some years and many agent platforms are available both from the industry and research community, there are currently few examples where the technology has been deployed in the real world. One important reason for this is that using the current available agent frameworks it is quite difficult to develop applications without having to center them completely on the agents and on the agent infrastructure. In this paper, we present the M&M project, taking place at the University of Coimbra. In this project, we are developing an extensive component-based framework that enables ordinary applications to use mobile agents in a flexible and easy way. By using this approach, applications can be developed using current object-oriented approaches and become able of sending and receiving agents by the simple drag-and-drop of mobility components. The framework was implemented using the JavaBeans component model and provides integration with ActiveX, which allows applications to be written in a wide variety of programming languages. By using this framework, the development of applications that can make use of mobile regents is greatly simplified, which can contribute to a wider spreading of the mobile agent technology.     

Morphometric study of the equine navicular bone: comparisons between fore and rear limbs

Navicular bones collected from the four limbs of 95 sound horses were studied. The anatomic bases have been laid down about morphometry of the navicular bones and their variations according to limbs, after corrections have been made for morphologic type, gender, weight, size and age. All the dimensions of the navicular bone (except for the thickness) were larger in the fore limb. This phenomenon probably reflects an attempt to compensate for the greater forces exerted upon the fore limbs during exercise and at rest. Navicular bones collected from the four limbs of 61 sound horses were studied and the anatomic bases were described for histomorphometry of the fore and rear navicular bones. Fore navicular bones possess less cortical bone at the level of the articular surface, as well as at the level of the flexor surface and proximal border, but larger amounts of cancellous bone. Articular and flexor surface cortical bone show a larger porosity in the fore navicular bones and a larger amount of mineralized cartilage. The mineralized portion for distal impar- and collateral sesamoidean ligaments are also larger for the fore navicular bones. Two distinct zones are observed for the flexor surface cortex that have never been reported in the literature before: an external zone, which is mainly composed of poorly remodelled lamellar bone, arranged in a disto-proximal oblique direction, and an internal zone, which is mainly composed of secondary bone, with a latero-medial direction of Haversian canals. Bone architecture is discussed with regard to the mechanic load, encountered by the bone during locomotion.     

Functionally distinct memories for imprinting stimuli: Behavioral and neural dissociations.

Precocial chicks exposed to a stimulus subsequently approach that stimulus in preference to other, novel stimuli. Previous investigations of the neural basis of these imprinting preferences suggest that imprinting training results in the formation of two memories. The first memory is formed rapidly and is located in the intermediate and medial part of the hyperstriatum ventrale (IMHV) of the left hemisphere; the formation of the second, in another memory system, S', takes several hours and can be prevented by a lesion placed in the right IMHV soon after training. The results of the present study suggest that the functional characteristics of these memories differ. Although memories in both left IMHV and S' supported imprinting preferences (Experiments 1a and 2a), only memories in S' influenced the acquisition of a heat-reinforced discrimination in which imprinted objects served as discriminanda (Experiments 1b and 2b). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Direct observation in the millisecond time range of fluorescent molecule asymmetrical interaction with the electropermeabilized cell membrane

Interaction of two stains (propidium iodide and ethidium bromide) with electropermeabilized living Chinese hamster ovary cells is observed using an ultrafast fluorescence image acquisition system. The computing process is linked to an ultra-low-light intensifying camera working with a very short time resolution (3.33 ms per image). Altered parts of the cell membrane were identified via the enhancement in fluorescence intensity of the dyes. They reflect the electropermeabilized part of the membrane in which free flow of dye occurred. Images of the fluorescence interaction patterns of the two dyes, in a maximum 20-ms time lag after pulsation, reveal asymmetrical permeabilization of the cell membrane. For electric field intensities higher than a first threshold value, permeabilization is always observed on the anode-facing side of the cell. For electric field intensities over a second higher threshold value, the two electrode-facing hemispheres of the cell are permeabilized, the hemisphere facing the anode being most permeable. These data support the conclusion that electropermeabilization of living cell membrane is affected by its resting potential. The asymmetrical pattern of the dye interaction is not dependent on the nature or concentration of the dye, the ionic strength of the pulsing buffer, or the duration of the pulse. The field intensity determines the fraction of the membrane in which molecular alterations can occur. The extent of alteration in this localized region is determined by the duration of the pulse when a single pulse in the millisecond time range is applied.