Micromachined multichannel systems for the measurement of cellular metabolism

Using living cells as the biological recognition element in a biosensor has two important advantages: cell receptors provide functional rather than structural specificity, and the cells provide second messenger pathways that amplify the receptor/ligand binding events. Cellular responses can be detected by measuring extracellular acidification with a silicon sensor. By using silicon micromachining technology, we can integrate the fluidic pathways and chambers for immobilizing cells with the silicon sensor. We describe a multichannel chip in which each channel is etched into the surface, and has its own flow of tissue-culture medium past the cells. Measurements have been made on adherent cells in which a muscarinic acetylcholine receptor is transfected. Responses to the agonist carbachol are shown.     

A NEW APPROACH FOR THE DETERMINATION OF MSD OF ASPHALT CEMENT USING HPGPC

ABSTRACT

A comparison between spectrophotometry and gravim-etry to study MSD of asphalt is presented. Spectrophotometry suffers from not detecting saturated compounds, as well as from variation of molar absorptivity during analysis. To address this, an asphalt sample is fractionated, and the relative molar absorptivity determined for each fraction. Using another sample weight of the whole asphalt, the saturates are separated, and injected to get their MSD using refractive index detection. This information - when used to mathematically treat the whole asphalt distribution data - can correct the latter to include saturates as well, but can only partially account for continuous variation of the molar absorptivity.

Gravimetry is not susceptible to the above, or other, limitations. The accuracy, comparing weight injected with that collected, equals ±0.56 mg, and the maximum difference between double analyses is 1.4%

Two identical, UV-detected MSD profiles did exhibit distinctly different MSD data using gravimetry     

Rigidity checking of 3D point correspondences under perspectiveprojection

An algorithm is described which rapidly verifies the potential rigidity of three-dimensional point correspondences from a pair of two-dimensional views under perspective projection. The output of the algorithm is a simple yes or no answer to the question “Could these corresponding points from two views be the projection of a rigid configuration?” Potential applications include 3D object recognition from a single previous view and correspondence matching for stereo or motion over widely separated views. The rigidity checking problem is different from the structure-from-motion problem because it is often the case that two views cannot provide an accurate structure-from-motion estimate due to ambiguity and ill conditioning, whereas it is still possible to give an accurate yes/no answer to the rigidity question. Rigidity checking verifies point correspondences using 3D recovery equations as a matching condition. The proposed algorithm improves upon other methods that fall under this approach because it works with as few as six corresponding points under full perspective projection, handles correspondences from widely separated views, makes full use of the disparity of the correspondences, and is integrated with a linear algorithm for 3D recovery due to Kontsevich (1993). Results are given for experiments with synthetic and real image data. A complete implementation of this algorithm is being made publicly available     

Lightner Witmer: A centennial tribute.

Clinical psychology had its origins 100 years ago when Lightner Witmer, at the University of Pennsylvania, established the first psychological clinic. Witmer was later responsible for a number of other key contributions to clinical psychology, including giving the discipline its name and founding its first journal. Although the field has advanced greatly since Witmer's pioneering period, the basic values that he espoused continue to characterize the profession. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attitudes of schizophrenics and normals toward success and failure.

The purpose of this study was to test the hypothesis that schizophrenics, as compared with normals, are relatively more highly motivated to avoid failure than to achieve success. A total of 291 Ss, including 136 hospitalized male schizophrenics, 103 normals, and--as a contrast group--52 neurotics, were administered the Success-Failure Inventory (SFI), a 22-item True-False instrument designed to assess attitudes toward success attainment and failure avoidance. As predicted, the schizophrenic samples manifested greater relative failure avoidance than the normals. Further, active schizophrenics evidenced greater relative failure avoidance than did remitted schizophrenics. Remitted schizophrenics and neurotics were not significantly different. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Mechanical Microelectrode Pulsing Device to Facilitate the Penetration of Small Cells

An electromagnetic electrode driving device which produces a relatively pure axial motion has been developed. The motion takes place in a few milliseconds, and its amplitude can be adjusted over a range of about ?-30 ?m. The device has been used to penetrate cells with a diameter of about 5 ?m.