The effect of cooking on proteins from acha (Digitaria exilis) and durum wheat

The effect of cooking on proteins from acha and durum wheat was assessed from an analysis of protein extractability, gel electrophoretic profiles, in-vitro protein digestibility (IVPD) and the amino acid compositions of wholemeal flour and residue proteins. Heating wholemeal flour samples at 100–140°C (t = 10–40 min) resulted in 0–30% and 45–55% decreases in acha and durum protein solubility, respectively. In general, high molecular weight (30–70 k Da) protein subunits were more susceptible to heat damage. For both cereals, sodium dodecyl sulphate (SDS; 10 g litre^?1) and/or dithiothrcitol (DTT; 10 mM ) increased protein solubility in unheated and heated samples. The IVPD index was 90–91% and was not significantly altered by cooking (100–120°C, t = 40 min). Cooking at extreme temperatures (140°C, t = 40 min) reduced the IVPD by 8% (P = 0.05). Osborne fractionation resulted in a durum or acha residue level of 7.8% or 55.2%. Treatment with solvent containing propanol, SDS and/or DTT at room temperature followed by SDS-polyacrylamide gel electrophoresis of non-solubilised proteins showed that the glutelin fraction of acha, with the exception of a 65 kDa subunit, was insoluble owing to strong inter-subunit hydrophobic and disulphide interactions. Wholemeal acha flour and residue protein showed a significantly greater level of hydrophobic and sulphur amino acids as well as glutamine which is associated with H-bonding. The possibility that cereal protein solubility is also dependent on protein-carbohydrate links is discussed.     

The implementation of channel diversity in mobile software radio receivers

A novel channel diversity concept is proposed and demonstrated, which avoids receiving signal deterioration due to multipath fading in mobile receivers. The system is based on coherent superposition of the signals received from several transmitters supplying the same information at different frequencies. Based on a software radio architecture this concept may increase the quality of mobile reception in modern car receivers considerably. Compared with multiantenna-receivers which overcome the multipath fading problem by simultaneously receiving the same program with several antennas, the proposed solution is advantageous, since it requires only a single antenna.     

Design aspects of MOS-controlled thyristor elements: technology,simulation, and experimental results

2.5-kV thyristor devices have been fabricated with integrated MOS controlled n⁺-emitter shorts and a bipolar turn-on gate using a p-channel DMOS technology. Square-cell geometries with pitch variations ranging from 15 to 30 μm were implemented in one- and two-dimensional arrays with up to 20000 units. The impact of the cell pitch on the turn-off performance and the on-state voltage was studied for arrays with constant cathode area as well as for single-cell structures. By realizing MOS components with submicrometer channel lengths, scaled single cells are shown to turn off with current densities of several kiloamperes per square centimeter at a gate bias of 5 V. In the case of multi-cell ensembles, turn-off performance is limited due to inhomogeneous current distribution. Critical process parameters as well as the device behavior were optimized through multidimensional numerical simulation     

Elevation of serum cholesterol levels in mice by the antioxidant butylated hydroxyanisole

The food antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are structurally related to the hypocholesterolemic drug probucol. The purpose of this study was to determine if BHA can lower serum cholesterol levels as is observed with probucol. Treatment of mice with 0.75% BHA in their feed for 10 days resulted in a significant (P < or = 0.01) elevation of serum cholesterol levels. This effect contrasts with the cholesterol-lowering effect of probucol. Further, the degree of cholesterol elevation was comparable to that observed in mice administered 3% cholesterol in their feed for 7 days. The enzyme acyl CoA:cholesterol acyltransferase (ACAT) was decreased significantly (P < or = 0.01) in liver microsomes from BHA-treated mice. In contrast, hepatic microsomal ACAT activity was increased significantly (P < or = 0.01) in cholesterol-fed mice. These results suggested that the increased serum cholesterol observed in BHA-treated mice was not accompanied by an increase in hepatic cholesterol levels. Indeed, hepatic microsomal cholesterol levels were reduced in BHA-treated mice, but were increased significantly (P < or = 0.01) in cholesterol-fed mice. These results demonstrate that the common food additive BHA elevates serum cholesterol levels by a mechanism that apparently involves the decreased uptake of cholesterol by the liver.     

Linear and nonlinear methods for brain-computer interfaces

At the recent Second International Meeting on Brain-Computer Interfaces (BCIs) held in June 2002 in Rensselaerville, NY, a formal debate was held on the pros and cons of linear and nonlinear methods in BCI research. Specific examples applying EEG data sets to linear and nonlinear methods are given and an overview of the various pros and cons of each approach is summarized. Overall, it was agreed that simplicity is generally best and, therefore, the use of linear methods is recommended wherever possible. It was also agreed that nonlinear methods in some applications can provide better results, particularly with complex and/or other very large data sets.     

The positive-acting sulfur regulatory protein CYS3 of Neurospora crassa: nuclear localization, autogenous control, and regions required for transcriptional activation

The positive-acting global sulfur regulatory protein, CYS3, of Neurospora crassa turns on the expression of a family of unlinked structural genes that encode enzymes of sulfur catabolism. CYS3 contains a leucine zipper and an adjacent basic region (b-zip), which together constitute a bipartite sequence-specific DNA-binding domain. Specific anti-CYS3 antibodies detected a protein of the expected size in nuclear extracts of wild-type Neurospora under conditions in which the sulfur circuit is activated. The CYS3 protein was not observed in cys-3 mutants. Nuclear extracts of wild type, but not cys-3 mutants, also showed specific DNA-binding activity identical to that obtained with a CYS3 protein expressed in Escherichia coli. A truncated CYS3 protein that contains primarily the b-zip domain binds to DNA with high specificity and affinity in vitro, yet fails to activate gene expression in vivo, and instead inhibits the function of the wild-type CYS3 protein. Amino-terminal, carboxyterminal, and internal deletions as well as alanine scanning mutagenesis were employed to identify regions of the CYS3 protein that are required for its trans-activation function. Regions of CYS3 carboxy terminal to the b-zip motif are not completely essential for function although loss of an alanine-rich region results in decreased activity. All deletions amino terminal to the b-zip motif led to a complete loss of CYS3 function. Alanine scanning mutagenesis demonstrated that an unusual prolinerich domain of CYS3 appears to be very important for function and is presumed to constitute an activation domain. It is concluded that CYS3 displays nuclear localization and positive autogenous control in Neurospora and functions as a trans-acting DNA-binding protein.