The influence of electron beam irradiation on the shear bond strength of glass-reinforced frameworks and veneer composites

The bond between glass fibre framework and veneer composite can be achieved by silane coupling agents or by monomers that penetrate into a polymer network. However, it has been clinically demonstrated that his bond can fail. This study investigated whether electron beam irradiation improved the bond strength of fibre-frameworks and veneer composite with and without additional coupling agents.     

Potential for detection of explosive and biological hazards with electronic terahertz systems

The terahertz (THz) regime (0.1-10 THz) is rich with emerging possibilities in sensing, imaging and communications, with unique applications to screening for weapons, explosives and biohazards, imaging of concealed objects, water content and skin. Here we present initial surveys to evaluate the possibility of sensing plastic explosives and bacterial spores using field-deployable electronic THz techniques based on short-pulse generation and coherent detection using nonlinear transmission lines and diode sampling bridges. We also review the barriers and approaches to achieving greater sensing-at-a-distance (stand-off) capabilities for THz sensing systems. We have made several reflection measurements of metallic and non-metallic targets in our laboratory, and have observed high contrast relative to reflection from skin. In particular, we have taken small quantities of energetic materials such as plastic explosives and a variety of Bacillus spores, and measured them in transmission and in reflection using a broadband pulsed electronic THz reflectometer. The pattern of reflection versus frequency gives rise to signatures that are remarkably specific to the composition of the target, even though the target's morphology and position is varied. Although more work needs to be done to reduce the effects of standing waves through time-gating or attenuators, the possibility of mapping out this contrast for imaging and detection is very attractive.     

A series of rare earth silicates RE3+2M3+[SiO4]2 (OH)

A series of isotypic silicates of composition RE₂M[SiO₄]₂ (OH) with RE = La³⁺, Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, and M = Al³⁺, Fe³⁺ has been synthesized under hydrothermal conditions. Lattice constants of two members as determined from single crystal X-ray diffraction data are: La₂Al[SiO₄]₂ (OH) (La₂Fe[SiO₄]₂ (OH)) $\text{a}{}_{\mathrm{o}}\text{= 7.401 (7.346)}\text{A}\text{?}$, $\text{b}{}_{\mathrm{o}}\text{= 5.702 (5.862)}\text{A}\text{?}$, $\text{c}{}_{\mathrm{o}}\text{= 17.072 (97.196)}\text{A}\text{?}$, gb = 112.4 (112.5°), $\text{P}\text{2}{}_1\text{c}$, Z=4.     

Determination of respiratory frequency from respiratory sinus arrhythmia

In the clinical setting, the observation of undisturbed spontaneous respiration and direct measurement of an "unbiased" respiratory rate is not a practical option. However, the respiratory modulation of the heart rate (respiratory sinus arrhythmia, RSA) offers a possibility of recording the respiratory rate indirectly. The present work introduces a novel procedure for extracting the respiratory rate from the ECG, and compares the results thus obtained with those of a previously applied method. The latter is based on the determination of dominant peaks in the amplitude spectrum of a five-minute RR interval time series. The new method presented here is based on the band pass filtering of a one-minute RR interval time series with subsequent analysis of the maxima, minima and zero crossings of the resulting RSA curve. The methods were compared by determining the respiratory rates of 16 healthy male subjects measured in 15 different experimental situations, including spontaneous and controlled breathing. The respiratory rate as determined by thermistor recording of nasal breath temperature was used as control. The mean deviation from directly measured respiratory rate was 2.9 min-1 for the new and 7.2 min-1 for the previous method. The new method proved superior under all conditions except controlled breathing at low frequencies. The present study thus demonstrates the high precision of respiratory rate determined indirectly by analysing the RSA curve. Since it requires no special instrumentation, this procedure is ideally suited for clinical application, and permits the continuous recording of respiratory rate over long periods of time.     

Development and Standardization of Testing Equipment and Methods for Spacer Fabrics

Applied Composite Materials - Spacer fabrics are three-dimensional textile structures consisting of two textile cover surfaces and a spacer thread. Up to now, spacer fabrics have been tested...     

Steatosis and Steatohepatitis: Complex Disorders

Non-alcoholic fatty liver disease (NAFLD) which includes steatosis and steatohepatitis, in particular non-alcoholic steatohepatitis (NASH), is a rising health problem world-wide and should be separated from alcoholic steatohepatitis (ASH). NAFLD is regarded as hepatic manifestation of the metabolic syndrome (MetSy), being tightly linked to obesity and type 2 diabetes mellitus (T2DM). Development of steatosis, liver fibrosis and cirrhosis often progresses towards hepatocellular carcinogenesis and frequently results in the indication for liver transplantation, underlining the clinical significance of this disease complex. Work on different murine models and several human patients studies led to the identification of different molecular key players as well as epigenetic factors like miRNAs and SNPs, which have a promoting or protecting function in AFLD/ASH or NAFLD/NASH. To which extent they might be translated into human biology and pathogenesis is still questionable and needs further investigation regarding diagnostic parameters, drug development and a better understanding of the genetic impact. In this review we give an overview about the currently available knowledge and recent findings regarding the development and progression of this disease.     

Permeation of binuclear, sulphur containing aromatic compounds

Removal of sulphur containing aromatics from fuel is strictly regulated and thus interesting for research as well as for industrial application. Especially difficult is the removal of complex dinuclear thiophenes and their methylated derivatives with conventional hydrotreating technology. Pervaporation could be an alternative separation technology. In order to find out if the separation of the more complex aromatics is possible, especially in low concentrations, variation of separation conditions and development of suitable membrane materials is necessary. The synthesized membrane materials based on 6FDA-4MPD/DABA copolyimides were analyzed by size exclusion chromatography (SEC) and differential thermal analysis (DTA) in combination with thermogravimetric analysis (TGA). In this work temperature-dependent pervaporation experiments were carried out with benzothiophene (about 0.25 wt.%) and n-dodecane as components of a binary feed mixture. The temperature has been varied between 80 °C and 140 °C. Thereby fluxes between 4.1 kg μm m^− 2 h ^− 1 and 32 kg μm m^− 2 h ^− 1 were found. Enrichment factors up to β = 3.3 were reached. In summary, the pervaporation experiments have shown that a significant enrichment of dinuclear aromatic sulphur compounds in combination to an adequate flux is possible.     

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Aachen Technology Overview of 3D Textile Materials and Recent Innovation and Applications

Applied Composite Materials - This paper provides an overview of the recent definition, technologies and current trends regarding 3D fabrics. In this paper a definition of 3D fabrics, including...