An event routing service for distributed applications: computer telephony—a case study

This paper presents an event routing service (ERS) that represents a pattern for the establishment and processing of lightweight sessions between a source and a destination of events. It is based on the CORBA notification service. To illustrate the features of the proposed service, its application in computer telephony is discussed in detail. Most of the positive features of the ERS are inherited from the CORBA notification service, but its implementation requires a novel protocol describing the lightweight session establishment mechanism. The implementation of ERS is described and its application to routing events in a computer telephony system is presented. The paper concludes with a performance measurement study. Copyright © 2002 John Wiley & Sons, Ltd.     

A structure oriented compact thermal model for multiple heat source ASICs

This paper proposes a methodology for the extraction of a compact thermal model for multiple heat source devices, which can be used for estimation of the overall temperature field. This extraction is based on the physical parameters as well as on the layout and the packaging of the device. The model directly represents the regions surrounding a source by a resistance network containing the specific parameters of source and chip in analytical form, so that it is easy to vary parameters like power dissipation and thermal conductivity within a wide range. In order to obtain a good and fast approximation of the continuous case, the shape of the volume elements represented by a node in the network is chosen regarding the direction of the heat flow within these elements. Therefore these volume elements are not rectangular but pyramid- or parallelogram-like structures. The temperature fields of multiple sources add up for the total temperature distribution, by the use of a matrix field representation.     

Photodegradation of Lipofuscin in Suspension and in ARPE-19 Cells and the Similarity of Fluorescence of the Photodegradation Product with Oxidized Docosahexaenoate

Retinal lipofuscin accumulates with age in the retinal pigment epithelium (RPE), where its fluorescence properties are used to assess retinal health. It was observed that there is a decrease in lipofuscin fluorescence above the age of 75 years and in the early stages of age-related macular degeneration (AMD). The purpose of this study was to investigate the response of lipofuscin isolated from human RPE and lipofuscin-laden cells to visible light, and to determine whether an abundant component of lipofuscin, docosahexaenoate (DHA), can contribute to lipofuscin fluorescence upon oxidation. Exposure of lipofuscin to visible light leads to a decrease in its long-wavelength fluorescence at about 610 nm, with a concomitant increase in the short-wavelength fluorescence. The emission spectrum of photodegraded lipofuscin exhibits similarity with that of oxidized DHA. Exposure of lipofuscin-laden cells to light leads to a loss of lipofuscin granules from cells, while retaining cell viability. The spectral changes in fluorescence in lipofuscin-laden cells resemble those seen during photodegradation of isolated lipofuscin. Our results demonstrate that fluorescence emission spectra, together with quantitation of the intensity of long-wavelength fluorescence, can serve as a marker useful for lipofuscin quantification and for monitoring its oxidation, and hence useful for screening the retina for increased oxidative damage and early AMD-related changes.     

The Influence of Intravaginal Gestagens Treatment on the Morphological Features and Endometrial Steroid Hormone Receptors Content during Anestrus Type II in Dairy Cattle

Background: Gestagens are the most widely used therapy in anestrus type II. The aim of this research is to evaluate the effectiveness of the vaginal progesterone inserts therapy in anestrus type II in cows. Methods: The study was conducted on 33 cows. Progesterone (PR) and estrogen (ER) receptors expression in endometrium was assessed on a molecular level based on mRNA tissue expression. Additionally, blood 17ß-estradiol and progesterone levels were evaluated. Results: A decrease in mRNA expression of A and B PR and ER α was noted in treated and untreated animals. In the treated group, an increase of ERß mRNA expression was observed, while a decreased was found in untreated animals. There was increased PR, ERα and ß expression in endometrial tissue in treated cows, and decreased expression of these factors in untreated cows. In the treated group, recurrence of ovarian cyclicity was noted in 52% of animals and pregnancy was obtained in 34.8% of them, while in the untreated group, recurrence did not occur. In the control group, spontaneous recurrence of ovarian cyclicity was not observed. An increase of PR expression was correlated with increased proliferation of endometrial cells. Conclusions: It seems likely that the endometrium is well developed and ready for placentation after removing the exogenous source of progesterone and preventing the recurrence of cyclicity of ovaries.     

Polymorph Selectivity of Coccolith‐Associated Polysaccharides from Gephyrocapsa Oceanica on Calcium Carbonate Formation In Vitro

Coccolith‐associated polysaccharides (CAPs) are thought to be a key part of the biomineralization process in coccolithophores; however, their role is not fully understood. Two different systems that promote different polymorphs of calcium carbonate are used to show the effect of CAPs on nucleation and polymorph selection in vitro. Using a combination of time‐resolved cryo‐transmission electron microscopy and scanning electron microscopy, the mechanisms of calcite nucleation and growth in the presence of the intracrystalline fraction are examined containing CAPs extracted from coccoliths from Gephyrocapsa oceanica and Emiliania huxleyi, two closely related coccolithophore species. The CAPs extracted from G. oceanica are shown to promote calcite nucleation in vitro, even under conditions favoring the kinetic products of calcium carbonate, vaterite, and aragonite. This is not the case with CAPs extracted from E. huxleyi, suggesting that the functional role of CAPs in vivo may be different between the two species. Additionally, high‐resolution synchrotron powder X‐ray diffraction has revealed that the polysaccharide is located between grain boundaries of both calcite produced in the presence of the CAPs in vitro and biogenic calcite, rather than within the crystal lattice.     

Bulk Synthesis and Surface Patterning of Nanoporous Metals and Alloys from Supraspherical Nanoparticle Aggregates

Supraspheres (SS) composed of hundreds to thousands of metal nanoparticles (NPs) and crosslinked by dithiol linkers are assembled into larger structures, which are subsequently converted into nanoporous metals (NMs). Conversion is achieved by heating which removes organic molecules stabilizing the NPs and allows for NP fusion. Heating of SS solutions leads to NMs of overall macroscopic dimensions; localized radiation using collimated electron beam is used to prepare metallized surface micropatterns. Depending on the composition of supraspherical precursors, nanoporous materials composed of up to three metals can be obtained. Strategies for controlling pore size and nanoscale surface roughness of these materials are discussed.     

The importance of orientation in proton transport of a polymer film based on an oriented self-organized columnar liquid-crystalline polyether

We prepared membranes based on a liquid-crystalline side-chain polyether obtained by chemical modification of commercial poly(epichlorohydrin) (PECH) with dendrons. This polymer exhibited a columnar structure, which could form an ion channel in the inner part. The columns were successfully oriented by taking advantage of surface interactions between the polymer and hydrophilic substrates, as confirmed by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM) and optical microscopy between crossed polars (POM). Column orientation was found to be crucial for effective transport: the oriented membranes exhibited proton transport comparable to that of Nafion® N117 and no water uptake. An increase in sodium ion concentration in the feed phase suggested a proton/cation antiport. On the contrary, no proton transport was detected on unoriented membranes based on the same liquid-crystalline side-chain polyether or on unmodified PECH.     

Microfluidic mixers: from microfabricated to self-assembling devices

This paper begins with a survey of both passive and active microfluidic mixers that have been implemented in recent years. It then describes a micromixing device based on dynamic self-assembly. This device is easy to fabricate and has excellent working characteristics in the continuous-flow mode. The paper concludes with a brief discussion of possible applications of self-assembly in microfluidics.