Safe starting regions by fixed points and tightening

In this paper, we present a method for finding safe starting regions for a given system of non-linear equations. The method is an improvement of the usual method which is based on the fixed point theorem. The improvement is obtained by enclosing the components of the equation system by univariante interval polynomials whose zero sets are found. This operation is called “tightening”. Preliminary experiments show that the tightening operation usually reduces the number of bisections, and thus the computing time. The reduction seems to become more dramatic when the number of variables increases.     

Biochemical and biophysical characterization of refolded Drosophila DPP, a homolog of bone morphogenetic proteins 2 and 4

The mature C-terminal signaling domain of the Drosophila Decapentaplegic proprotein (DPP) can be efficiently refolded from chaotrope-solubilized inclusion bodies with the aid of a membrane protein-solubilizing detergent, high concentrations (0.75-2 M) of NaCl, and low temperatures (5-15 degreesC). The disulfide-linked homodimeric product contains N-terminal heparin-binding sites that were utilized as intrinsic affinity tags to obtain a highly enriched preparation in one chromatographic step. A subsequent C4 reverse phase high pressure liquid chromatography step provides high purity, salt-free protein that is amenable to biophysical and structural studies at a yield of approximately 3 mg/liter of bacterial culture. The dimeric protein is correctly folded as determined by electrophoretic, spectroscopic, chemical, and proteolytic analyses. Refolded DPP is also bioactive as shown by induction of chondrogenesis in embryonic chick limb bud cells and by high affinity binding to Noggin, an antagonist of bone morphogenetic protein signaling. In contrast to bone morphogenetic proteins extracted from demineralized bone or overexpressed in cell culture, the refolded Escherichia coli-expressed protein is not glycosylated at a conserved N-linked site and is therefore homogeneous. The C-terminal domain dimer is more hydrophobic and thus less soluble than its unfolded or partially folded forms, necessitating highly solubilizing conditions for recovery after folding in vitro. Hence solubilization of the mature ligand may be one of the principal roles of the large (250-400 amino acids) N-terminal prodomains of transforming growth factor-beta superfamily members, shown to act as intramolecular chaperones in vivo.     

Identification of naturally processed T cell epitopes from glutamic acid decarboxylase presented in the context of HLA-DR alleles by T lymphocytes of recent onset IDDM patients

Glutamic acid decarboxylase (GAD) has been defined as a major target antigen in insulin-dependent diabetes mellitus (IDDM). To identify the molecular ligands triggering a T cell response to GAD, a panel of human GAD65-specific T lymphocyte lines was generated from peripheral blood of three recent onset IDDM patients. All lines derived from a patient expressing the high-risk-conferring HLA-DR*0301/ *0401 haplotypes recognized a single epitope localized between amino acid positions 270 and 283 of GAD65, a stretch that is located in close proximity to the homology region shared with Coxsackie virus P2-C protein. All lines with this specificity were restricted to the DRA, B1*0401 product of the DR4 haplotype. Analysis of the GAD-specific T cell response in a second patient homozygous for DR4 haplotypes demonstrated that the same DRA, B1*0401 allele selected T cells specific for a different determinant. The T cell response profile in a third patient showed that DR*1501/ *1601-encoding haplotypes could present at least three different epitopes to GAD65-specific T lymphocytes. One of these epitopes was presented by a DR allele associated with the resistance-conferring DRB1*1501 haplotype. GAD-specific T cell lines could not be isolated from HLA class II-matched normal individuals. Our data reveal that (a) the T cell response to GAD65 is quite heterogenous in recent onset IDDM patients; (b) HLA-DR, not DQ, seems to be the principal restriction element used by T cells present at the onset of the disease; and (c) T cells responding to epitopes containing identical sequences to Coxsackie virus P2-C protein were not detected.     

Mesonephric origin of the gonadal primitive medulla in chick embryos

The development of the gonadal primitive medulla in embryonic chick gonads was studied with the light microscope, using serial longitudinal sections from 72 h to 108 h of incubation. The sex of embryos was established from karyotypes. At 72 h, the germinal epithelium in the genital ridges was thickened. The nephrogenic cord was not differentiated into nephrons underneath, although the surrounding mesonephros displayed renal corpuscles and tubules. Clusters and trabeculae of mobilized mesonephric cells piled up under the germinal epithelium, forming the rudiment of the primitive medulla. From 78 h onwards, nephrotome-like structures existed in the mesenchyme underlying the germinal epithelium. Mesonephric cells became detached from their ventral walls and incorporated into the rudiment of the medulla. Finally, at 90 h, when the gonads were constituted, the primitive medulla was definitively formed without any contribution of the germinal epithelium. Adrenal cortical cells, also originating from the mesonephric blastema, showed tight relationships with the gonadal medullarian structures. Our observations support the concept of the mesonephric origin of the gonadal components having male potentialities in birds.     

Performance of rats on the Maier Three-Table Task following septal lesions occurring 24 hours after birth.

Two experiments with 85 Long-Evans hooded rats studied whether behavioral sparing would be demonstrated when septal lesions occurred prior to the age at which the tested behavior first appears in normal rats. Ss given septal lesions at 1 or 7 days after birth performed at approximately chance on the Maier 3-table task when tested at 90 days of age. Ss that had control electrode insertions at the same ages performed at a level similar to normal Ss. Ss given septal lesions at either age explored significantly more than did control Ss. Results are discussed in terms of the constancy over time of the septal contribution to performance on the 3-table task and the involvement of the septum and hippocampus in the processing of spatial information. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermofraktographie zur Schnellanalyse von Kunststoffen. 2. Mitt. Identifizierung von Phenolharzen

Thermofractography is suitable for the rapid identification of phenolic resins. 3–4 mg of the material to be investigated are heated in the temperature gradient of 150–450°C. The thermofractogram shows the free phenols of the resin in the range of 150–250°C. The phenols developing through thermolysis from the condensation products appear, depending on the corresponding initial phenol, in the range of 300–450°C. The efficiency of the method is demonstrated on several novolaks and phenolresol.     

Chemical and organoleptic properties of dried emulsions

Safflower oil was incorporated into a model emulsion system containing emulsifier, carbohydrates, antioxidants, and protein. Emulsions were spray dried and the dry powders were stored at 60 C. Their oxidation rates were measured by headspace gas analysis (Oxygen absorption and carbon dioxide generation); peroxide and carbonyl values also were run. Although these objective tests all gave good correlation with average flavor scores, results show that oxygen absorption was superior to others as an indicator of flavor deterioration. Stepwise, multiple linear regression analysis showed that oxygen absorption and carbonyl value gave an equation which can predict flavor scores with a high degree of accuracy.     

The self-sufficient solar house in Freiburg

The Fraunhofer Institute for Solar Energy Systems has built a completely self-sufficient solar house (SSSH) in Freiburg, Germany. The entire energy demand for heating, domestic hot water, electricity, and cooking is supplied by the sun. The combination of highly efficient solar systems with conventional means to save energy is the key to the successful operation of the house. Seasonal energy storage is accomplished by electrolysis of water and pressurized storage of hydrogen and oxygen. The energy for electricity and hydrogen generation is supplied by solar cells. Hydrogen can be reconverted to electricity with a fuel cell or used for cooking. It also serves as a back-up for low temperature heat. There are provisions for short term storage of electricity and optimal routing of energy. The SSSH is occupied by a family. An intensive measurement program is being carried out. The data are used for the validation of the dynamic simulation calculations, which formed the basis for planning the SSSH.