An intrinsic behavior-based model for interactive structural design

This paper introduces a generic model for interactive design of constructed facilities. The proposed methodology synthesizes structural problem parameters and conditions in terms of load environment, structural properties, and function of the structure into a hierarchy of possible failure modes. Design evaluations are made in terms of this behavior hierarchy. The user has a high degree of control over the design process and may move at will to any of the design tasks. The model provides a direct link between the system user and the design evaluations during the evaluation/design process.     

How Perception Impacts on Drawings.

In 3 experiments the authors investigate how errors in perception produce errors in drawings. In Experiment 1, when Shepard stimuli were shown as a pair of tables, participants made severe errors in trying to adjust 1 part of the stimulus to match the other. When the table legs were removed, revealing a pair of parallelograms with minimal perspective cues, the illusion was weaker. The authors predicted that participants would err when drawing the table but not the parallelogram stimuli. The results of Experiment 2 support the prediction and establish a direct link between degree of perceptual distortion of the table stimuli and the severity of error in drawing. When drawing only the right-hand part of the figure, participants also erred to a greater degree in drawing the table than the parallelogram (Experiment 3). Collectively, the results suggest that perceptual distortion is linked with errors in drawing the table stimuli. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Lucifer Yellow as a live cell fluorescent probe for imaging water transport in subcellular organelles

While the water permeability of the plasma membranes of mammalian cells has been studied extensively, water transport across membranes of subcellular compartments (e.g., lysosomes, macropinosomes) has been difficult to study. Here we demonstrate a new method for measuring water flux in late endosomes and lysosomes of intact living cells using time-lapse fluorescence microscopy. Cells were loaded by fluid-phase uptake with a mixture of the Lucifer Yellow dextran (LY-dex), a D(2)O sensitive dye, and a D(2)O insensitive control dye, Alexa fluor 546 dextran (AF546-dex). LY-dex responded linearly to changes in D(2)O concentration and the LY-dex D(2)O sensitivity was not affected by changes in pH, physiological salt, and protein concentrations. The co-loaded control dye, AF546-dex, showed no signal changes as a function of D(2)O concentration. To measure membrane water flux, the LY-dex fluorescence in labeled organelles was recorded during rapid superfusion of cells with isotonic buffers prepared in D(2)O. The time constant of water exchange across the lysosomal membrane of intact cells was determined by fitting the data to a single exponential function. From these data, together with the measured area of the organelles, observed water permeability for intracellular CHO-K1 lysosomes was calculated to be 5.3 × 10(-3) ± 0.3 × 10(-3) cm/s. This work demonstrates the feasibility of measuring water flux into subcellular organelles in live cells using LY-dex.     

Double heterozygosity for mutations in the BRCA1 and BRCA2 genes in a breast cancer patient

BACKGROUND: Germline mutations in the tumor suppressor genes BRCA1 and BRCA2 confer substantial increased lifetime risk for breast cancer, and in the case of BRCA1, for ovarian carcinoma as well. These two genes alone account for the vast majority of hereditary breast cancer families. Numerous mutations have been described in each gene, the majority of which are small insertions or deletions resulting in expression of a truncated protein. MATERIALS AND METHODS: Several common mutations can be detected using a polymerase chain reaction-mediated, site-directed mutagenesis assay, which transforms the amplicon derived from either the wild-type or mutant allele by adding or removing a restriction endonuclease site. We screened 49 putative sporadic breast tumors using this methodology, targeting four BRCA1 mutations (185delAG, 5382insC, R1443X, and E1250X) and a single BRCA2 mutation (6174delT). RESULTS: Using the polymerase chain reaction-mediated, site-directed mutagenesis assay, we identified two mutations, namely, a 185delAG mutation (BRCA1) and a 6174delT mutation (BRCA2). Interestingly, these two mutations were found in the same sample. None of the remaining 48 breast tumors showed evidence of these mutations. Allele-specific oligonucleotide probes were then employed in conjunction with the Universal GeneComb Test Kit, which confirmed the presence of mutations. CONCLUSIONS: Our data suggest that the common germline BRCA1 and BRCA2 mutations are infrequently encountered in sporadic breast cancers. The one case with dual BRCA1 and BRCA2 mutations suggests that this tumor may be hereditary in origin, despite the lack of a positive family history. Double heterozygosity for mutations in BRCA1 and BRCA2 may have increasingly significant implications with regard to predisposition to breast cancer.     

A finite element method for neutron transport—III. Two-dimensional one-group test problems

The even-parity transport equation for an isotropic scattering medium is applied using a maximum principle to determine the angular flux in a square lattice cell with a cylindrical fuel element, a square isotropic source in a corner of an absorbing shield and a dog-leg duct through an absorbing shield. The finite element solutions obtained are compared with an exact solution for the cell, and benchmark results for the square source and duct problem. The accuracies achieved for the fluxes in the cell problem are everywhere better than 0.75% and high accuracy is achieved for the other test problems. The linear elements, used for the spatial dependence of the angular flux in conjunction with a spherical harmonic expansion for the angular dependence, provide a flexible means of treating awkward geometries. At present the equations are assembled and solved using the UNCLE code, which uses direct Gaussian elimination. This process limits the speed of the finite element method to about 1/3 of the Fletcher finite difference spherical harmonics method for the square source problem. This latter method is, however, limited to systems with geometries defined by co-ordinate surfaces, whereas the finite element method can be used for any region that can be triangulated.     

A variational treatment for the time dependent boltzmann equation as a basis for numerical solutions conserving neutrons

A maximum principle for the time-dependent first-order Boltzmann equation is established in two independent ways:- by a generalized least squares method and by a method based on the properties of an appropriate bi-linear form. The second derivation suggests a metric for a Hilbert space which provides a geometrical interpretation of the variational principle. This interpretation leads to a Petrov-Galerkin weighted residual method in contrast to the Galerkin method of Martin for time dependent transport.

The maximum principle is used to define a figure of merit for the global error of any numerical solution for time dependent transport. The principle is used also to demonstrate the neutron conservation property of optimized numerical solutions, and the convergence of finite element methods based on the variational principle.

A direct use of the maximum principle give a conservative three level scheme for transients in the angular flux. A less massive calculation for a conservative solution proceeds in two stages. The first stage obtains a preliminary solution based on a sequence of tailored steady state calculations for the even-parity angular flux. The relevant equations are derived by making residual terms vanish in the variational principle. They are equivalent to the finite element - finite difference equations used by de Oliveira and Wood for the analysis of oil-well logging by means of a neutron pulse. For the second stage the preliminary solution is weighted at each time step. The weights are determined by the maximum principle to yield a conservative solution which is continuous in time. The solution can be arranged to have also a continuous time derivative. Thus the maximum principle can be used both as a way of predicting and correcting solutions.     

Teletraffic Analysis for Single-Cell Mobile Radio Telephone Systems

Formulas are derived for the congestion in single-cell mobile radio systems in which there are both land-to-mobile and mobile-to-mobile calls and in which mobile-to-mobile calls go via the base station. Two approaches are used. The first yields modified forms of the familiar Erlang and Engset formulas. The second gives more complicated but more accurate formulas. The results of computer simulations to establish the accuracy of the formulas are described.     

Incidence of fatal pulmonary embolism after 1,390 knee arthroplasties without routine prophylactic anticoagulation, except in high-risk cases

OBJECTIVE: To determine whether the time of administration (morning vs. evening) of pantoprazole influences the effect of a 40 mg dose upon intragastric pH in healthy subjects. DESIGN: Randomized, double-blind, two-period crossover study to compare intragastric pH following treatment with pantoprazole, 40 mg once daily for 7 days, the drug being given as either a morning or an evening dose before meals. METHODS: Intragastric pH was measured for 24 h on three occasions. The baseline recording was made 2 days prior to the first treatment period and subsequent measurements were made on days 6 to 7 of each period. Adverse events were recorded and fasting laboratory variables measured. RESULTS: Twelve subjects were evaluable for efficacy. Increases in median pH over 24 h were observed in all subjects with both dosage regimens. There was a greater increase from baseline in 24-h median pH values following morning than evening administration of pantoprazole (P < 0.05). This difference was due to a greater effect on median daytime pH (07.00-19.00 h, P < 0.01) compared with that after evening administration. No adverse events were reported and there were no clinically significant changes in laboratory variables. CONCLUSION: The study supports the recommendation of a once-daily morning dosage regimen of pantoprazole 40 mg in the treatment of acid-related diseases.