Social development from infancy to adolescence: Longitudinal and concurrent factors in an adoption sample.

In the present longitudinal study, early adopted children (N = 160) were followed from infancy to adolescence to assess the influence of previous and concurrent factors on the children's social development. This study allowed for more conclusive evidence of the influence of early and concurrent rearing experiences and temperament on adolescents' social development, independent of shared genetic factors between children and parents. Results showed that social development and temperament were stable over time and that both previous and current parental sensitivity were important in predicting social development in adolescence. Quality of the early parent-child relationship was indirectly associated with social development in adolescence through the influence on social development in middle childhood. Maternal sensitivity in middle childhood and in adolescence partly buffered the negative effects of difficult temperament on social development in adolescence. Adaptation emerged as the product of both developmental history and current circumstances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of wood load condition by Near Infrared (NIR) spectroscopy

The assessment of the mechanical properties of wood using non-destructive evaluation (NDE) tools has been widely developed and refined. These NDE tools mainly rely on vibrational, ultrasonic or stress-wave approaches. Vibrational techniques generally show higher correlations between the estimated modulus of elasticity (MOE), or modulus of rupture (MOR), and the measured MOE, or MOR, than stress-wave techniques. They are, however, relatively difficult to apply in the field due to boundary conditions common in many timber structures. Thus, improved tools for assessing timber structures are still needed. Recently, near infrared (NIR) spectroscopy (500–2400 nm) has shown promise for predicting the MOE and MOR of wood. This work focuses on extending the use of NIR for measuring the load applied to small wood beams. The reflectance NIR spectrum was measured as the applied load was increased. Good correlations (r > 0.96) between the measured load and the predicted load were obtained using spectra taken from both the tension and compression surfaces of the small wood beams.     

The role of interfacial segregation and microstructure in interdiffusion between aluminum and silicon

In this investigation, we studied the interdiffusion behavior between polycrystalline silicon (poly-Si) and aluminum where the poly-Si was doped with antimony via ion implantation. Post sintering sample microstructure was determined by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and optical microscopy, and composition was determined by Rutherford Backscattering Spectrometry (RBS) and Scanning Auger Microscopy. As-implanted samples showed interdiffusion during sintering (465° C, dry N₂) independent of Sb concentrations up to 1.1 × 10²¹ cm⁻³ near the Al/Si interface. In samples where the implantation damage was annealed out prior to sintering, interdiffusion is inhibited when the Sb concentration at the interface was above a threshold concentration of 7.3 × 10¹⁹ cm⁻³. This threshold concentration is lower if the segregation of Sb is preserved prior to metallization. We propose that interdiffusion is inhibited by dopant (Sb) passivation of interfacial Si defects, the sites where interdiffusion is believed to initiate. MIT work supported by NSF contract 84-18718-DMR.     

Covariance between components of biaxial stress state in fatigue life calculations

In this paper influence of correlalions between components of random stress tensor on the calculated fatigue life of the machine element has been analysed. Two groups of covariance matrices for components of biaxial stress state were considered. The first group was arbitrarily assumed and the second one was determined on the basis of the measured strains in the element of the vibrating screen for aggregate. Computer simulation was realized with four criteria of multiaxial random fatigue. Cycles were counted with the method of rain flow and damages were cumulated according to Palmgren-Miner hypothesis. It has been shown that covariances between components of stress state tensor strongly influence the calculated fatigue life.     

ESTIMATED AND EXPERIMENTAL FATIGUE LIVES OF 30CrNiMo8 STEEL UNDER IN-AND OUT-OF-PHASE COMBINED BENDING AND TORSION WITH VARIABLE AMPLITUDES

Abstract— Calculated fatigue lives, based on three criteria for multiaxial random fatigue, were compared with lives obtained from tests on cylindrical specimens of 30CrNiMo8 steel subjected to in- and out-of-phase bending and torsion at variable amplitudes. In the chosen fatigue criteria the expected position of the fracture plane, determined from a variance method for the equivalent stress, were taken into account. The equivalent stress history was related to the rain flow method and fatigue damage was evaluated from the Palmgren–Miner hypothesis. It has been shown that the expected fatigue fracture planes agree with those determined by experiments. The most realistic estimations of fatigue life were obtained by the criterion of maximum shear and normal stresses on the fracture plane using a modified shear stress.     

Fibroblast cells: a sensing bioelement for glucose detection by impedance spectroscopy

Modifying the electrical properties of fibroblasts against various glucose concentrations can serve as a basis for a new, original sensing device. The aim of the present study is to test a new biosensor based on impedancemetry measurement using eukaryote cells. Fibroblast cells were grown on a small optically transparent indium tin oxide semiconductor electrode. Electrochemical impedance spectroscopy (EIS) was used to measure the effect of D-glucose on the electrical properties of fibroblast cells. Further analyses of the EIS results were performed using equivalent circuits in order to model the electrical flow through the interface. The linear calibration curve was established in the range 0-14 mM. The specification of the biosensors was verified using cytochalasin B as an inhibitor agent of the glucose transporters. The nonreactivity to sugars other than glucose was demonstrated. Such a biosensor could be applied to a more fundamental study of cell metabolism.     

Cholesterol oxidases: a study of nature's approach to protein design

Cholesterol oxidases are important as clinical reagents, potential larvicides, and tools in cell biology, and they are implicated in bacterial pathogenesis. Here we review chemical aspects of their function. We describe our current structural and mechanistic understanding of the type I and II cholesterol oxidases, our identification of an NH-pi hydrogen bond motif for stabilization of reduced flavins, our structural hypothesis of how O(2) gains access to the flavin, and our present understanding of type I cholesterol oxidase-lipid bilayer interactions.