Guessing Tangents in Normal Flows

Given a flow field parallel to isophote normals, a normal flow field, we seek a unobservable tangential field as the minimum of a general energy functional of the total field. We generalize existing methods to any linear, differential operator order on the combined field while keeping the projection onto the isophote normal constant. We discuss invariant flow fields, present a novel iterative solution based on Euler-Lagrange equations, prove continuous convergence, and give synthetic examples for common energy functionals. Possible uses are: estimating physical flow in image sequences, estimating human growth processes, and co-warping textures in animation sequences.     

Experimental and theoretical assessment of flexural properties of hybrid natural fibre composites

The concept of hybridization of natural fibre composites with synthetic fibres is attracting increasing scientific attention. The present study addresses the flexural properties of hybrid flax/glass/epoxy composites to demonstrate the potential benefits of hybridization. The study covers both experimental and theoretical assessments. Composite laminates with different hybrid fibre mixing ratios and different layer configurations were manufactured, and their volumetric composition and flexural properties were measured. The relationship between volume fractions in the composites is shown to be well predicted as a function of the hybrid fibre mixing ratio. The flexural modulus of the composites is theoretically assessed by using micromechanical models and laminate theory. The model predictions are compared with the experimentally determined flexural properties. Both approaches show that the flexural modulus of the composites is consistently increased when the flax fibre fabrics are replaced by glass fibre fabrics from the inner layers to the outer layers. The observed deviations between the experimental and theoretical values are explained by the simplifying model assumptions applied for the configuration of the composites, in particular the flax fibre composites. This needs to be addressed in further work.     

Soluble, prolonged-acting insulin derivatives. I. Degree of protraction and crystallizability of insulins substituted in the termini of the B-chain

Hydrophilic insulins, more positively charged than human insulinat neutral pH, have been prepared by substitution with basicamino acids at the termini of the B-chain and by blocking theC-terminal carboxyl group of the B-chain. The iso-electric pHof the insulin is thereby moved from 5.4 towards physiologicallevels. Slightly acid solutions of derivatives, in which chargehas been added in the C-terminus of the B-chain, have a prolongedaction in vivo, in particular if the carboxyl group is blocked.It is found that the prolong ed-acting hydrophilic insulinscrystallize instantly when the pH is adjusted to 7. The prolongedaction is ascribed to this readiness to crystallization combinedwith a low solubility, which may be further decreased by Increasedconcentration of zinc ions. Hydrophobic insulins have a prolongedaction independent of the site of substitution even if the derivativeis soluble at physiological pH. Some derivatives were preparedfrom porcine Insulin by tryptic transpeptidatlon. N-terminalB-chain substituted insulins were prepared by alkylation ofa biosynthetic single-chain insulin precursor, followed by tryptictranspeptidation rendering the double chain insulin derivative.The observed blood glucose lowering in the rabbits implies thatneither N- nor C-terminal B-chain substitution results in substantialdeterioration of biological potency. An index for the degreeof protraction based on the blood glucose data is used to comparethe insulins.     

Production of antisera to synthetic benzyloxycarbonyl-C-peptide of human proinsulin

Antisera to the C-peptide of human proinsulin were obtained by immunizing guinea pigs with synthetic benzyloxycarbonyl-C-peptide conjugated to human albumin with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. In three series of 10, the animals were injected with C-peptide conjugated to albumin in the molar ratio of 23 : 1, 15 : 1, and 4 : 1, respectively. Antibodies to human C-peptide were present in all the surviving 25 animals. Fifteen of the antisera were suitable for measuring C-peptide concentrations lower than 0.10 pmol/ml. The antisera demonstrated an increasing immunogenicity with increasing molar ratio of C-peptide to albumin in the conjugate. In the fourth series, ten guinea pigs immunized with benzyloxycarbonyl-C-peptide ionically bound to QAE-Sephadex A-25 did not produce detectable antibodies to C-peptide. A qualitative evaluation of the radioimmunoassay by use of the antiserum with the highest titer and sensitivity, "M 1230", revealed a mean intra-assay and inter-assay coefficient of variance of 3.2 and 9.6%, respectively.     

Observation of quantum interference in molecular charge transport

As the dimensions of a conductor approach the nanoscale, quantum effects begin to dominate, and it becomes possible to control the conductance through direct manipulation of the electron wavefunction. Such control has been demonstrated in various mesoscopic devices at cryogenic temperatures, but it has proved to be difficult to exert control over the wavefunction at higher temperatures. Molecules have typical energy level spacings (～eV) that are much larger than the thermal energy at 300?K (～25?meV), and are therefore natural candidates for such experiments. Previously, phenomena such as giant magnetoresistance, Kondo effects and conductance switching have been observed in single molecules, and theorists have predicted that it should also be possible to observe quantum interference in molecular conductors, but until now all the evidence for such behaviour has been indirect. Here, we report the observation of destructive quantum interference in charge transport through two-terminal molecular junctions at room temperature. We studied five different rigid π-conjugated molecular wires, all of which form self-assembled monolayers on a gold surface, and find that the degree of interference can be controlled by simple chemical modifications of the molecular wire.     

Second Order Structure of Scale-Space Measurements

The second-order structure of random images f :? ^d →? ^N is studied under the assumption of stationarity of increments, isotropy and scale invariance. Scale invariance is defined via linear scale space theory. The results are formulated in terms of the covariance structure of the jet consisting of the scale space derivatives at a single point. Operators describing the effect in jet space of blurring and scaling are investigated. The theory developed is applicable in the analysis of naturally occurring images of which examples are provided.     

Reaction mechanism of trypsin-catalysed semisynthesis of human insulin studied by fast atom bombardment mass spectrometry

The production of semisynthetic human insulin for therapeuticpurposes is of considerable importance. During trypsin-catalysedtransformation of pig insulin into an ester of insulin of humansequence, the alanyl residue at position B³⁰ is removed andreplaced with an esterified residue of threonine. We have carriedout this transformation in a medium enriched in ¹⁸OH₂ and studiedthe product by MS. In contrast to a previous report, we findthat incorporation of label into the B²⁹–B³⁰ peptide bondoccurs during the transformation with threonine methyl esterin aqueous N, N-dimethylacetamide. Quantitative data are presentedand the implications of these findings are discussed.     

Separation of the two double-chain bovine intermediates of the proinsulin-insulin conversion I. Chemical, immunochemical, circular dichroism, and biological characterization

The intermediates of the proinsulin-insulin conversion were separated by cation exchange. The circular dichroism spectra of the intermediates showed less alpha-helix than insulin and proinsulin. It is suggested that the C-peptide interacts with the section of alpha-helix contained between residues 2 and 8 in the A-chain of the insulin moieties and unwinds the alpha-helix. The in vivo activities of the intermediates were found to be in the order of 50% relative to insulin. In the fat cell assay, the A-chain-substituted form is weaker (9%) than the B-chain-substituted form (19%). The C-peptide segments of the two forms reacted with C-peptide-specific antibodies as fully as the free C-peptide, on a molar basis. In contrast, the insulin segments were hindered from reacting with insulin-specific antibodies as fully as the insulin.     

Modeling transport in ultrathin Si nanowires: charged versus neutral impurities

At room temperature dopants in semiconducting nanowires are ionized. We show that the long-range electrostatic potential due to charged dopants has a dramatic impact on the transport properties in ultrathin wires and can virtually block minority carriers. Our quantitative estimates of this effect are obtained by computing the electronic transmission through wires with either charged or neutral P and B dopants. The dopant potential is obtained from density functional theory (DFT) calculations. Contrary to the neutral case, the transmission through charged dopants cannot be converged within a supercell-based DFT scheme, because the system size implied by the long-ranged electrostatic potential becomes computationally unmanagable. We overcome this problem by modifying the DFT potential with finite element calculations. We find that the minority scattering is increased by a factor of 1000, while majority transmission is within 50% of the neutral dopant results.     

Bovine factor XIIa inhibitor

Four work life demonstration projects designed to upgrade home aide employment, reduce turnover, and increase continuity of care were evaluated using randomly selected experimental and control groups at each of 11 agencies. The projects reduced worker turnover in the experimental groups from 10 to 44 percentage points. Where it was measured, continuity of care also significantly improved. Local political, economic, and competitive conditions affected the viability of the projects, which added from $.09 to $1.43 to the aides' hourly wage.