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Notes: We report the first study of quantum confinement shifts of energy gap in strained Si0.84Ge0.16/Si quantum wells at room temperature by photothermal deflection spectroscopy (PDS) technique. The experimental results obtained from the amplitude and phase of the PDS signal are in good agreement with quantum well subband calculation.

Notes: Without any post physical or chemical patterning a Tl-base high temperature superconducting film has been observed to pattern spontaneously on SrTiO3 (100) by liquid-gas-solidification process. The film exhibits the morphology of a microelectric network in which the directions of growth of the crystal walls follow the directions of the SrTiO3 (100) substrate. The crystal walls consisting of Tl-1223 and Tl-1212 phases are 0.25–1 μm wide, 2 μm high, and a few millimeters long. These walls are proposed to grow from independent nucleation sites and coalescence to form semiconductive junctions. The network exhibits a superconducting transition onset at 113 K and approaches zero resistance at 95 K. Below 95 K, the resistance increases exponentially with decreasing temperature. This strongly suggests that the films form a natural superconductor/semiconductor/superconductor junction array.

Notes: The activity and diffusivity of oxygen in a liquid Yb1Ba2Cu3 high temperature superconducting precursor alloy have been measured by modified coulometric titration method in a temperature range from 913 to 957 °C. The standard Gibbs formation energies and the diffusivity of oxygen in liquid Yb1Ba2Cu3 for 1/2O2 (1 atm)→O (1 at. %) are determined to be ΔG=−655.20+0.335T(K) (±1.5) kJ/mol and D=1.8×10−2 exp(−48 100/RT) (cm2/s) where R=8.314 J/deg×mol. Despite very strong bonding of oxygen to the liquid alloys, the diffusion coefficient of oxygen is relatively high in the order of 10−4 cm2/s. The solubility of oxygen in the liquid alloy is low, of about 0.0145 and 0.017 at. % at 913 and 935 °C, respectively.

Notes: In pure oxygen at moderate temperatures of 200 °C, an fcc C60 transforms into amorphous carbon-oxygen compounds and the icosahedral C60 molecular structure is destroyed. The maximum oxygen uptake of pure C60, O/C60, is 12. Isothermal TGA transformation curves are sigmoid-shaped with the kinetic exponent n∼5/2 which conforms with a two-dimensional nucleation and growth mode. The heat of formation for the carbon-oxygen compounds is 90 kcal/mol O, and the formation energy for the reaction: 60C (graphite)→C60 molecule is estimated to be ∼600 kcal/mol.

Notes: Aspergillus species are common airborne fungi that have been identified as causative agents of extrinsic bronchial asthma. More than 10 allergens from A. fumigatus have been recently characterized by cDNA cloning.The objective of this study is to identify A. fumigatus allergens through immunoblot analysis using sera from asthmatic patients.IgE-binding components of A. fumigatus and IgE cross-reactivity among allergens of different prevalent airborne fungal species were analysed by immunoblot and immunoblot inhibition, respectively, using sera from asthmatic patients. The N-terminal amino acid sequences of major allergens identified were determined by Edman degradation.Among two batches (70 and 41 sera) of asthmatic sera tested, 19 (27%) and 14 (34%), respectively, have IgE immunoblot reactivity towards components of A. fumigatus. A 34-kDa protein that reacts with IgE antibodies in 15 (79%) and 11 (79%) of the 19 and 14 positive samples, respectively, may be considered a major allergen of A. fumigatus. The N-terminal amino acid sequences of the 34 kDa major allergen and the 30.5 and 30 kDa IgE-binding components of A. fumigatus showed sequence identity to that of the vacuolar serine proteinase from A. fumigatus. The results from immunoblot inhibition show IgE cross-reactivity among major allergens of A. fumigatus, P. notatum and P. oxalicum.Results obtained suggest that the 34 kDa major allergen of A. fumigatus may be a vacuolar serine proteinase. There is IgE cross-reactivity among serine proteinase allergens of A. fumigatus, P. notatum and P. oxalicum.

Notes: Alkaline and/or vacuolar serine proteinases are major allergens in prevalent airborne Penicillium and Aspergillus species.〈section xml:id="abs1-2"〉〈title type="main"〉ObjectiveThe object of this study is to generate and characterize monoclonal antibodies against these serine proteinase allergens.〈section xml:id="abs1-3"〉〈title type="main"〉MethodsBALB/c mice were immunized individually with the Penicillium citrinum culture medium or the crude extract and culture medium preparations of Aspergillus fumigatus. Hybridoma cells that secrete monoclonal antibodies against serine proteinase allergens were selected by immunoblotting. Antigens in three different Penicillium (P. citrinum, P. notatum and P. oxalicum) and two different Aspergillus species (A. fumigatus, and A. flavus) recognized by these monoclonal antibodies were analysed by sodium dodecyl sulphate and two-dimensional polyacrylamide gel electrophoresis immunoblotting and N-terminal amino acid sequence analysis.〈section xml:id="abs1-4"〉〈title type="main"〉ResultsFour (PCM8, PCM10, PCM16 and PCM39) and one (FUM20) monoclonal antibodies against serine proteinase allergens were generated after fusion of NS-1 cells with spleen cells obtained from BALB/c mice immunized with antigens from P. citrinum and A. fumigatus, respectively. Immunoblotting results showed that PCM8 reacted with an alkaline serine proteinase allergen in P. citrinum and P. notatum. PCM10 and PCM39 reacted with the alkaline serine proteinase in two Penicillium (P. citrinum, P. notatum) and two Aspergillus species (A. fumigatus, and A. flavus) tested. PCM16 reacted with the alkaline serine proteinase allergen in P. citrinum, A. fumigatus and A. flavus but not with that in P. notatum. MoAb FUM20 reacted with the alkaline serine proteinase allergen in two Aspergillus species (A. fumigatus and A. flavus) but not with that in two different Penicillium species (P. citrinum, P. notatum) tested. Among these five monoclonal antibodies generated, only PCM39 and FUM20 can react with the vacuolar serine proteinase allergen in P. notatum, P. oxalicum and in A. fumigatus. The 35 kDa P. citrinum component that reacted with FUM20 has an N-terminal amino acid sequence of DSPSVEKNAP.〈section xml:id="abs1-5"〉〈title type="main"〉ConclusionFive monoclonal antibodies against different epitopes of the serine proteinase major allergens in prevalent Penicillium and Aspergillus species were generated in the present study. Antibodies obtained may be useful in the characterization and standardization of serine proteinase allergens in crude fungal extracts.

Notes: Background Through proteomic and genomic approaches we have previously identified and characterized an alkaline serine protease that is a major allergen (88% frequency of IgE binding) of Penicillium chrysogenum (Pen ch 13).Objective The aim of the present study is to identify the linear IgE-binding epitopes of Pen ch 13.Methods IgE-binding regions were identified by dot-blot immunoassay using 11 phage-displayed peptide fragments spanning the whole molecule of Pen ch 13. The minimal epitope requirements for IgE binding were further defined with overlapping peptides synthesized on derivatized cellulose membranes using SPOTs technology. The critical residues on the immunodominant epitopes were mapped through site-directed mutagenesis. The locations of the IgE epitopes identified were correlated with a three-dimensional structure of Pen ch 13.Results IgE antibodies in 35 serum samples reacted with at least one of the 11 peptide fragments of Pen ch 13. Peptide f-2n (residues 31–61) showed a high-intensity and the highest frequency (77%) of IgE binding. The frequencies of IgE binding to peptide f-4 (residues 93–133), f-1 (residues 1–37) and f-7 (residues 168–206) were 51%, 34% and 31%, respectively. SPOTs assay narrowed down the region of IgE binding of f-2n to residues 48–55 (GHADFGGR). Three, two and one epitope(s) that are four to nine amino acids in length, within f-4, f-1 and f-7, respectively, were found. Site-directed mutagenesis of Pen ch 13 revealed that substitution of His49 and/or Phe52 on Pen ch 13 with methionine resulted in proteins with drastic loss of IgE binding in seven sera tested. Proteins with amino acid replacements at residues 15–18 (RISS), or at residues 112 (I) and 116 (D) have lower IgE-binding reactivity in one of the two patient's sera tested. Substituting residues 117 (W), 119 (V) and 120 (K) also block most of the IgE binding in one of the two patient's sera tested. In addition, replacing residues 203 (V) and 204 (D) along with a deletion at residue 206 (Y) diminished the IgE binding in two serum samples tested. A model was constructed based on the structure of P. cyclopium subtilisin protease that has 〉90% (256 out of 283 amino acids) sequence identity with Pen ch 13. The major epitope (GHADFGGR) on Pen ch 13 formed a loop-like structure and was located at the surface of the allergen.Conclusions Several linear IgE-reactive epitopes and their critical core amino acid residues were identified for the Pen ch 13 allergen. The major linear IgE-binding epitope, 48GHADFGGR55, formed a loop-like structure at the surface of the allergen. Substitution of His49 and/or Phe52 with methionine significantly reduced IgE-binding to Pen ch 13. Mapping of these results on a 3D model of the allergen provides valuable information about the molecular basis of allergenicity for Pen ch 13 and for designing specific immunotherapeutics.

Notes: The effectiveness of antioxidants was studied in methyl linoleate-carbohydrate model systems at the intermediate moisture content. Systems showing sorption hysteresis were used in the range of Aw0.68–0.84. Metal chelating agents were found to be more effective than free radical chain terminators. The antioxidant effectiveness of EDTA (a chelator) was greater in the higher moisture desorption systems since more would be expected to be in solution. The work also showed that metal catalyst activity is responsible for the rapid oxidation rates in intermediate moisture systems as compared to dry systems.