Topological design of modular structures under arbitrary loading

A numerical method for the topological design of periodic continuous domains under general loading is presented. Both the analysis and the design are defined over a single cell. Confining the analysis to the repetitive unit is obtained by the representative cell method which by means of the discrete Fourier transform reduces the original problem to a boundary value problem defined over one module, the representative cell. The repeating module is then meshed into a dense grid of finite elements and solved by finite element analysis. The technique is combined with topology optimization of infinite spatially periodic structures under arbitrary static loading. Minimum compliance structures under a constant volume of material are obtained by using the densities of material as design variables and by satisfying a classical optimality criterion which is generalized to encompass periodic structures. The method is illustrated with the design of an infinite strip possessing 1D translational symmetry and a cyclic structure under a tangential point force. A parametric study presents the evolution of the solution as a function of the aspect ratio of the representative cell.     

Teaching the introductory course in psychology circa 1900.

Teachers of introductory courses in psychology and those who wrote the textbooks for the courses at the start of the 20th century represented the new psychology that replaced the old psychology of mental philosophy. Teachers and texts presented psychology as a natural science of the mind and mental processes, described its methods, and suggested its potential applications to practical concerns. Textbooks and teachers varied in their approaches to psychology, their priorities among its methods, and their emphases on applying psychology. The introductory course in psychology accurately reflected the state of the discipline at the turn of the century. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Allergen arrays for antibody screening and immune cell activation profiling generated by parallel lipid dip-pen nanolithography

Multiple-allergen testing for high throughput and high sensitivity requires the development of miniaturized immunoassays that allow for a large test area and require only a small volume of the test analyte, which is often available only in limited amounts. Developing such miniaturized biochips containing arrays of test allergens needs application of a technique able to deposit molecules at high resolution and speed while preserving its functionality. Lipid dip-pen nanolithography (L-DPN) is an ideal technique to create such biologically active surfaces, and it has already been successfully applied for the direct, nanoscale deposition of functional proteins, as well as for the fabrication of biochemical templates for selective adsorption. The work presented here shows the application of L-DPN for the generation of arrays of the ligand 2,4-dinitrophenyl[1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[6-[(2,4-dinitrophenyl)amino]hexanoyl] (DNP)] onto glass surfaces as a model system for detection of allergen-specific Immunoglobin E (IgE) antibodies and for mast cell activation profiling.     

Salivary cortisol: a non-invasive measure of hypothalamo-pituitary-adrenocortical activity in the squirrel monkey, Saimiri sciureus

STUDY OBJECTIVES: To study the in vitro effects of the serotonin2 (5-HT2) receptor agonist 1-(2.5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) in skeletal muscle specimens from malignant hyperthermia-susceptible (MHS) and normal (MHN) patients following pretreatment with the 5-HT2 receptor antagonist ritanserin. DESIGN: Prospective study. SETTING: Malignant hyperthermia (MH) laboratory at a university hospital. PATIENTS: 41 patients undergoing in vitro contracture test for diagnosis of MH susceptibility. INTERVENTIONS: Skeletal muscle biopsies in adult patients were performed with a 3-in-1 nerve block with 40 ml prilocaine 1%. In children, general anesthesia was induced with 50 micrograms/kg alfentanil intravenously (i.v.) and 2 to 2.5 micrograms/kg propofol i.v. and maintained with a continuous infusion of propofol (< or = 150 micrograms/kg/min) and nitrous oxide (66%) in oxygen. MEASUREMENTS AND MAIN RESULTS: Patients were first classified as MHS or MHN by the in vitro contracture test according to the European MH protocol. Surplus muscle specimens of 21 MHS and 20 MHN patients were used in this study. At first, DOI was added to the organ bath at a concentration of 0.02 mM. In the second part of the study, muscle specimens were preincubated with ritanserin 0.01 mM for 10 minutes before DOI 0.02 mM was added to the bath. Muscle specimens from all patients developed contractures after administration of DOI. The onset of contractures was significantly faster in MHS muscles, and the magnitude of contracture was significantly greater than in MHN. The muscle twitch decreased significantly in both groups after DOI. After pretreatment with ritanserin, start of contracture was significantly delayed in MHS muscles. MHN muscles failed to develop contractures. The maximum level of contracture was significantly reduced in MHS. Muscle twitch decreased also in both MHS and MHN groups. CONCLUSIONS: The findings may indicate that stimulation of 5-HT2 receptors is involved in MH induction. Furthermore, 5-HT2 receptor antagonists could possibly be effective in preventing MH. Additional studies are required to determine if administration of 5-HT2 receptor antagonists could be of additional value in the treatment or prevention of anesthetic-induced MH.     

POD Evaluation: The Key Performance Indicator for NDE 4.0

The magnified images of thin wires, plastic, steel and lead plates which were obtained using linear microfocus hard bremsstrahlung generated through interaction of an 18 MeV electron beam with a 13 μm thick Ta foil oriented along the internal beam of a B-18 betatron are presented. The images indicate high absorption contrast of the objects due to a small horizontal size of the radiation source the width of which is 115-fold smaller than the diameter of the electron beam. Some results have shown a few peculiarities in the images which were not earlier observed. Several results were compared with the ones obtained earlier using the microfocus bremsstrahlung generated by the 18 MeV electron beam of B-18 in a narrow Si target.

     

Immunological detection of membrane-associated human luteinizing hormone correlates with gene expression in cultured human cancer and fetal cells

We have demonstrated the expression of membrane-associated hCG and its subunits and fragments by cells from 78 human cancer cell lines of different types and origins, indicating that such expression is a common phenotypic characteristic of cultured human malignant cells. Because human (h) LH beta has 80% homology with hCG beta and is coded by one of the seven genes in the gene cluster located in chromosome 19, it was important to determine whether hLH and its beta-subunit are also expressed as membrane-associated proteins by cells from human cancer cell lines. Thus, 11 cancer cell lines of different types and origins were adapted to grow in serumless medium, with Nutridoma-HU or SP as serum substitute, and analyzed by flow cytometry using two monoclonal antibodies directed to different conformational epitopes of intact hLH and a monoclonal antibody reacting with an epitope of hLH beta-free. The cells were also analyzed simultaneously for the expression of hCG and its subunits and fragments. Determination of translatable levels of hLH beta and hCG beta messenger RNAs (mRNAs) was performed in cells from some of the cancer cell lines, including the JEG-3 choriocarcinoma cell line, and in cells from a human fetal lung cell line. The analytical flow cytometry studies showed that in addition to the expression of membrane-associated hCG in all of its forms, expression of membrane-associated intact (holo) hLH and its free beta-subunit occurred in every case. These findings were corroborated by the presence of translatable levels of hLH beta and hCG beta mRNAs in all of the cancer cell lines analyzed, indicating that the expression of these membrane-associated glycoproteins is a phenotypic characteristic of human cancer cells and that the activation of the hCG beta-hLH beta gene cluster is nonselective. The presence of translatable levels of hCG beta-hLH beta mRNAs in the cultured human fetal lung cells punctuates once more the in vivo and in vitro biochemical similarities between fetal and cancer cells.     

Salbutamol enhances isotonic contractile properties of rat diaphragm muscle

The effects of the beta2-adrenoceptor agonist salbutamol (Slb) on isometric and isotonic contractile properties of the rat diaphragm muscle (Diamus) were examined. A loading dose of 25 microg/kg Slb was administered intracardially before Diamus excision to ensure adequate diffusion. Studies were then performed with 0.05 microM Slb in the in vitro tissue chamber. cAMP levels were determined by radioimmunoassay. Compared with controls (Ctl), cAMP levels were elevated after Slb treatment. In Slb-treated rats, isometric twitch and maximum tetanic force were increased by approximately 40 and approximately 20%, respectively. Maximum shortening velocity increased by approximately 15% after Slb treatment, and maximum power output increased by approximately 25%. During repeated isotonic activation, the rate of fatigue was faster in the Slb-treated Diamus, but both Slb-treated and Ctl Diamus fatigued to the same maximum power output. Still, endurance time during repetitive isotonic contractions was approximately 10% shorter in the Slb-treated Diamus. These results are consistent with the hypothesis that beta-adrenoceptor stimulation by Slb enhances Diamus contractility and that these effects of Slb are likely mediated, at least in part, by elevated cAMP.     

A data acquisition and image processing system for scanning tunneling microscopy

We have built a dedicated data acquisition and image processing system for scanning tunneling microscopy (STM). Data acquisition is accomplished by a fast 8-bit add-on frame grabber which may be synchronized either to standard TV frequencies or to asynchronous slow scan data sources such as STM or SEM. A 32-bit minicomputer is used for image processing by means of a comprehensive interactive-language which also allows the data acquisition process to be controlled. To speed up time-consuming computations, a floating-point array processor was linked to the system.