Subacute proteome changes following traumatic injury of the developing brain: Implications for a dysregulation of neuronal migration and neurite arborization

Traumatic brain injury (TBI) is a major cause of morbidity and mortality among children and adolescents. To gain insight into developmental events influenced by TBI, we analyzed subacute mouse brain proteome changes in a percussion head trauma model at P7 ipsi- and contralateral to the site of injury. The comparison of brain proteomes of trauma mice and controls revealed reproducible changes in the intensity of 28 proteins (30 protein spots) in response to trauma. The changes detected suggest that TBI leads to apoptosis, inflammation, and oxidative stress. These changes were consistent with our results of histological and biochemical evaluation of the brains which revealed widespread apoptotic neurodegeneration, microglia activation, and increased levels of protein carbonyls. Furthermore, we detected changes in proteins involved in neuronal migration as well as axonal and dendritic growth and guidance, suggesting interference of trauma with these developmental events.     

Electronic Structure and Superconductivity of Nonmagnetic Transition Metal Borocarbides

The electronic structure of tetragonal (RC(N))_m(TB)₂, m=1–3, compounds, with R= Y,Lu,La, T=Ni,Pt is studied. Total and partial densities of states N(E) are calculated and compared with orbital resolved x-ray absorption data. Special attention is paid to the structure of N(E) near the Fermi-level and its consequences for thermodynamic properties in the superconducting and the normal states. A medium el-ph coupling constant 0.5 1.2 is found. There is no simple correlation between N(0) and T _c . The analysis of the upper critical field reveals the presence of at least two groups of electrons with quite different Fermi velocities v _F in accord with dHvA data, and with calculated distributions of v _F around the Fermi surface     

Difficulties in the transition from OO analysis to design

The transition from object-oriented (OO) analysis to OO design is indeed difficult. Unfortunately, most of the literature on this topic has incorrectly assessed this issue since the notion of OO analysis was introduced about a decade ago     

Dynamics of incomplete ionized dopants and their impact on4H/6H-SiC devices

The influence of incomplete ionization of dopants in 4H/6H-SiC on transient device behavior has been investigated numerically based on a self-consistent solution of the coupled system of Poisson's equation, the continuity equations of electrons and holes, and balance equations for each donor or acceptor level. If the rise time of a reverse bias pulse is equal or smaller than the characteristic ionization time constant, a dynamically enlarged extension of depletion regions is obtained which can result in a dynamic punchthrough (PT) within back-to-back junction configurations. The respective time constants of nitrogen (N), aluminum (Al), and boron (B) mere measured as functions of temperature in 4H- and 6H-SiC using thermal admittance spectroscopy (AS) and deep level transient spectroscopy (DLTS). At room temperature, for instance, we obtained 60 ps/2 ps, 300 ps/10 ps, and 100 ns/100 ns for N (cubic site), Al, and B in 4H/6H-SiC, respectively. As the time constants of N and Al are small, transient incomplete ionization turns out to be negligible, at least within today's high-power device operation areas. Boron, on the other hand, influences significantly the dynamic device characteristics. In order to demonstrate the implications of these effects, numerical device simulations of a 6H-SiC double-implanted MOSFET and a 4H-SiC thyristor were performed. These simulations allow a detailed analysis of the transient device behavior and the onset of dynamic PT which strongly depends on temperature, structure parameters, and the external excitation     

Knowledge acquisition using hypertext

This paper addresses the issue of supporting knowledge acquisition using hypertext. We propose a way of tightly integrating hypertext and structured object representation, using Artificial Intelligence (AI) frames for the basic representation of hypertext nodes. Epistemologically, a dual view of the resulting space is of interest. One view is that of hypertext which emphasizes nodes containg g text, including formal knowledge representation. The other view focuses on objects with certain relationships, which define a semantic network. Both in hypertext and in semantic networks the relations between chunks of knowledge are explicitly represented by links. However, in today's hypertext systems a node typically contains just informal text and references to other nodes. Our approach additionally facilitates the explicit representation of structure “inside” hypertext nodes using partitions. We show the usefulness of such a tight integration for knowledge acquisition, providing several features useful for supporting it based on a level of basic hypertext functionality. In particular, we sketch a method for doing knowledge acquisition in such an environment. Hypertext is used as a mediating “semiformal” representation, which allows experts to directly represent knowledge without the immediate support of knowledge engineers. These help then to make this knowledge operational, supported by the system's facility to provide templates as well as their links to the semiformal representation. As an example of our results of using this method of knowledge acquisition, we illustrate the strategic knowledge in our application domain. More generally, our approach supports important aspects of (software) engineering knowledge-based systems and their maintenance. Also their user interface can be improved this way.     

Mössbauer studies of Gd-doped bismuth-based ceramic superconductors

The results of¹⁵⁵Gd Mössbauer studies (above 1·5K) of the oxides, Bi_3·5Gd_0·5Ca₃Sr₃Cu₄O _y and Bi₂Sr₂Ca_1?x Gd _x Cu₂O _y (x=0·25 and 0·5) are reported. The observed electric quadrupolar split resonance patterns suggest that Gd ions prefer to occupy Ca site in both series. The spectral features give evidence for paramagnetic relaxation of isolated Gd ions at low temperatures.