A gated tunnel diode has been introduced into a wave-guide oscillator circuit and the gate is used to tune the oscillation frequency and to turn the oscillator on and off. Oscillators with oscillation frequencies in the range of 9-22 GHz with a typical oscillator output power about -20 dBm have been fabricated. We found that the output power remains essentially constant over a gate bias range (abo

Object detection in real images has attracted much attention during the last decade. Using machine learning and large databases it is possible to develop detectors for visual categories that have a very high hit-rate, with low false positive rates. In this paper we investigate a general probabilistic framework for context based scene interpretation using multiple detectors. Methods for finding max

The two flavodoxins (YkuN and YkuP) from Bacillus subtilis have been cloned, overexpressed in Escherichia coli and purified. DNA sequencing, mass spectrometry, and flavin-binding properties showed that both YkuN and YkuP were typical short-chain flavodoxins (158 and 151 amino acids, respectively) and that an error in the published B. subtilis genome sequence had resulted in an altered reading fram

ims In atrial fibrillation (AF), a relation between electrocardiogram (ECG) fibrillatory wave amplitude and thrombus formation has been sought for long with conflicting results. In contrast, the possible relation between atrial fibrillatory rate obtained from the surface ECG and left atrial thrombus formation in patients with AF is unknown and was consequently evaluated in this study. Methods and

Multi-wall carbon nanotubes (MWNT) were used as reinforcement for melamine-formaldehyde (MF). They were oxidised in HNO3/ H2SO4 mixture and analyzed by means of X-ray Photoelectron Spectroscopy (XPS). Two anionic surfactants: sodium dodecyl sulphate (SDS) and sodium dodecylbenzenesulfonate (NaDDBS) were used to assist the dispersion of nanotubes. The MWNT content was varied from 0 to 1.0 wt%, and

Background Ulcerative colitis is characterized by relapsing mucosal inflammation where the lesions include tissue-damaging granulocytes. In addition, T cells and natural killer (NK) cells play important pathophysiologic roles. Chemokines are a large family of peptides that play key roles in the regulation of inflammation. The CXC-chemokines, growth-related oncogene (GRO)-alpha/CXCL1 and interleuki

An NMR technique to measure exchange kinetics at thermal equilibrium in dispersions of moderately soluble crystalline material is presented. By monitoring the exchange of molecules between pools in solid and dissolved form, one can characterize the surface specific exchange rate. Illustrative experiments were performed in a model system with b-type crystals of tripalmitin as the solid phase and tr

Background and Purpose: Leptin, an important hormone for body weight regulation, may be involved in the pathogenesis of cardiovascular manifestations of obesity. We tested whether leptin may be an independent risk marker for stroke in a case-referent study. Methods: Definitive acute stroke events, defined by MONICA criteria, were identified from October 1, 1995 to April 30, 1999. Referents without

Many shorebirds travel over large sections of the globe during the course of their annual cycle and use habitats in many different biomes and climate zones. Increasing knowledge of the factors driving variations in shorebird numbers, phenotype and behaviour may allow shorebirds to serve as 'integrative sentinels' of global environmental change. On the basis of numbers, timing of migration, plumage

Ectomycorrhizal mycelial systems were grown in unsterile soil using specially designed growth chambers, and the respiratory activity of the mycelium was measured before and after its excision from the host roots. Approximately 30% of the total respiration in the intact system was attributable to the mycorrhizal mycelium in the soil. Severance of mycelial connections at the roots lead to a greater

The interaction between localized and extended vibrational modes in solids is of central importance in understanding how local vibrational modes decay into phonons. Interstitial oxygen (O-i) in silicon is a model system for studying such interactions. Using hydrostatic pressure, we have brought the antisymmetric stretch mode of O-18(i) in silicon into resonance with the second harmonic of the O-18

Formal closed models for vehicular traffic flow are obtained based on the novel equilibrium solution of the Prigogine--Herman equation. To that effect, Hilbert and Chapman--Enskog asymptotic series expansions are employed, obtaining the Euler and Navier--Stokes equivalent equations for traffic flow.

In this paper, we present the expression and characterization of two novel enzymes from the a-amylase family exhibiting cyclomaltodextrinase specificity. The nucleotide sequences encoding the enzymes were isolated from the genomic DNA of two thermophilic bacterial strains originating from Icelandic hot springs and belonging to the genera Anoxybacillus (AfCda13) and Laceyella (LsCda13). The genes w

Using exact dispersion relations for electromagnetic wave propagation in layered, periodic media, consisting of two phases, we derive explicit asymptotic solutions for small wavenumbers. These solutions are compared to the numerical solutions of the exact dispersion relations, and applications to homogenization problems are discussed. The results can be used as test cases for homogenization techni

The many-body theory of photoemission in solids is reviewed with emphasis on methods based on response theory. The classification of diagrams into loss and no-loss diagrams is discussed and related to Keldysh path-ordering book-keeping. Some new results on energy losses in valence-electron photoemission from free-electron-like metal surfaces are presented. A way to group diagrams is presented in w

The ectomycorrhizal fungus Paxillus involutus efficiently took up exogenously supplied [C-14]alanine and rapidly converted it to pyruvate, citrate, succinate, fumarate and to CO2, thus providing direct evidence for the utilisation of alanine as a respiratory substrate. [C-14]alanine was further actively metabolised to glutamate, glutamine and aspartate. Exposure to aminooxyacetate completely suppr

Swedish cross-sectional survey data on young individuals was used to analyse the determinants of perceived risks of alcohol use and how these perceptions relate to drinking behaviour. Three major conclusions were drawn: (1) that people overestimate the risks of alcoholism, (2) that these risk perceptions fall substantially with age, but nevertheless imply risk overestimation, and (3) that educatio