Detection of optical and infrared radiation with DC-biased electron-tunneling metal-barrier-metal diodes

The voltage obtained from metal-barrier-metal (MBM) diodes by phase-sensitive detection when illuminated with optical and near-infrared radiation, modulated at 880 Hz, has been studied as a function of an applied dc bias. The detected voltage is a nonlinear function of the bias voltage for high junction impedances, and linear for low junction impedances. The nonlinearity in the junction has been shown to be consistent with electron tunneling theory.     

1H and13C HR-MAS NMR investigations on native and enzymatically digested bovine nasal cartilage

Rheumatic diseases are accompanied by a progressive destruction of the cartilage layer of the joints. Despite the frequency of the disease, degradation mechanisms are not yet understood and methods for early diagnosis are not available. Although some information on pathogenesis could be obtained from the analysis of degradation products of cartilage supernatants, the most direct information on degradation processes would come from the native cartilage as such. We have used¹H as well as¹³C HR-MAS (high resolution magic angle spinning) NMR spectroscopy to obtain suitable line-widths of NMR resonances of native cartilage. ID and 2D NMR spectra of native cartilage were compared with those of enzymatically-treated (collagenase and pa pain) samples. In the¹H NMR spectra of native cartilage, resonances of polysaccharides, lipids and a few amino acids of collagen were detectable, whereas the¹³C NMR spectra primarily indicated the presence of chondroitin sulfate. Treatment with papain resulted only in small changes in the¹H NMR spectrum, whereas a clear diminution of all resonances was detectable in the¹³C NMR spectra. On the other hand, treatment with collagenase caused the formation of peptides with an amino acid composition typical for collagen (glycine, proline, hydroxyproline and lysine). It is concluded that the HR-MAS NMR spectra of cartilage may be of significance for the investigation of cartilage degradation since they allow the fast evaluation of cartilage composition and only very small amounts of sample are required. © 2001 Elsevier Science B.V. All rights reserved.     

Emotion classification during music listening from forehead biosignals

Emotion recognition systems are helpful in human–machine interactions and clinical applications. This paper investigates the feasibility of using 3-channel forehead biosignals (left temporalis, frontalis, and right temporalis channel) as informative channels for emotion recognition during music listening. Classification of four emotional states (positive valence/low arousal, positive valence/high arousal, negative valence/high arousal, and negative valence/low arousal) in arousal–valence space was performed by employing two parallel cascade-forward neural networks as arousal and valence classifiers. The inputs of the classifiers were obtained by applying a fuzzy rough model feature evaluation criterion and sequential forward floating selection algorithm. An averaged classification accuracy of 87.05 % was achieved, corresponding to average valence classification accuracy of 93.66 % and average arousal classification accuracy of 93.29 %.     

Glasses formation,characterization, and crystal-structure determination in the Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>–Sb<Subscript>2</Subscript>O<Subscript>3</Subscript>–TeO<Subscript>2</Subscript> system prepared in an air

A glass-forming domain is found and studied within Bi₂O₃–Sb₂O₃–TeO₂ system. The glasses composition were obtained in pseudo-binary xSbO_1.5, (1−x)TeO₂ for 0.05 ≤ x ≤ 0.20. The constitution of glasses in the system Sb₂O₃–TeO₂ was investigated by DSC, Raman, and Infrared spectroscopy. The influence of a gradual addition of the modifier oxides on the coordination geometry of tellurium atoms has been elucidated based Infrared and Raman studies and showed the transition of TeO₄, TeO₃₊₁, and TeO₃ units with increasing Sb₂O₃ content. XRD results reveal the presence of three crystalline: γ-TeO₂, α-TeO₂, and SbTe₃O₈ phases during the crystallization process. The density of glasses has been measured. The investigation in the ternary system by the solid state reaction using XRD reveals the existence of a solid solution Bi_1−x Sb_1−x Te_2x O₄ isotopic to BiSbO₄ with 0 ≤ x ≤ 0.1.     

Explosive spalling of normal strength concrete slabs subjected to severe fire

The first part of this paper presents an experimental investigation on explosive spalling of six full-scale normal strength reinforced concrete slabs subjected to conventional fire curve ISO834 and severe hydrocarbon fire curve, performed at the Fire Research Centre, University of Ulster, UK focusing on concrete thermal behaviour and the explosive spalling phenomenon. Each slab was loaded with 65% of its BS8110 design load and was heated from the bottom side only. Temperatures profile was recorded at three depths within the slabs and the moisture content was also measured before and after the tests. The deflection of the slabs was recorded at the middle of the 3 m span. The second part of the paper presents a numerical study on the normal concrete slabs using the finite element method. The concrete slabs were modelled including the embedded reinforcement to conduct a non-linear transient structural analysis taking into account cracks appearance and creep. A comparison between the experimental and the FEM results is presented in the paper.     

Magnetic Properties of SrO Doped with 3d Transition Metals

Based on the density functional theory and using the Korringa–Kohn–Rostoker coherent potential approximation (KKR-CPA) method, we study the (Sr, TM)O doped systems where TM = V, Cr, Mn, Fe, Co, and Ni atoms. In particular, we start first by relaxing the parameters of the corresponding structures. Then we discuss its electronic structures, magnetic stabilities, and half-metal properties using 3d transition metals. Among others, it has been shown that doping with Cr, Mn, Fe, and Co, the ferromagnetic phase can be stabilized using a double exchange mechanism. Moreover, we find that the half-metallic properties of these compounds are formed due to a large exchange splitting and the delocalized properties of the majority spin e _g state and the minority spin t _eg states.     

Evaluation of Maillard Reaction Variables and Their Effect on Heterocyclic Amine Formation in Chemical Model Systems

Heterocyclic amines (HCAs), highly mutagenic and potentially carcinogenic by‐products, form during Maillard browning reactions, specifically in muscle‐rich foods. Chemical model systems allow examination of in vitro formation of HCAs while eliminating complex matrices of meat. Limited research has evaluated the effects of Maillard reaction parameters on HCA formation. Therefore, 4 essential Maillard variables (precursors molar concentrations, water amount, sugar type, and sugar amounts) were evaluated to optimize a model system for the study of 4 HCAs: 2‐amino‐3‐methylimidazo‐[4,5‐f]quinoline, 2‐amino‐3‐methylimidazo[4,5‐f]quinoxaline, 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline, and 2‐amino‐3,4,8‐trimethyl‐imidazo[4,5‐f]quinoxaline. Model systems were dissolved in diethylene glycol, heated at 175 °C for 40 min, and separated using reversed‐phase liquid chromatography. To define the model system, precursor amounts (threonine and creatinine) were adjusted in molar increments (0.2/0.2, 0.4/0.4, 0.6/0.6, and 0.8/0.8 mmol) and water amounts by percentage (0%, 5%, 10%, and 15%). Sugars (lactose, glucose, galactose, and fructose) were evaluated in several molar amounts proportional to threonine and creatinine (quarter, half, equi, and double). The precursor levels and amounts of sugar were significantly different (P < 0.05) in regards to total HCA formation, with 0.6/0.6/1.2 mmol producing higher levels. Water concentration and sugar type also had a significant effect (P < 0.05), with 5% water and lactose producing higher total HCA amounts. A model system containing threonine (0.6 mmol), creatinine (0.6 mmol), and glucose (1.2 mmol), with 15% water was determined to be the optimal model system with glucose and 15% water being a better representation of meat systems.