Infrared Reflection Spectroscopy and Effective Medium Modeling of As-Anodized and Oxidized Porous Silicon Carbide

We present a study of the infrared reflectance of porous silicon carbide (PSC) formed by the electrochemical dissolution of silicon carbide substrates of both 6H and 4H polytypes. The reflectance from n-PSC, both as-anodized and passivated, is reported for the first time. The passivation of PSC has been accomplished using a short thermal oxidation. Fourier transform infrared (FTIR) reflectance spectroscopy is employed ex situ after different stages of the thermal oxidation process. The characteristics of the reststrahlen band normally observed in bulk SiC are altered by anodization; further changes in the reflectance spectra occur following oxidation for different periods of time. An effective medium theory model that includes air, SiC and SiO₂ as component materials is shown to characterize the observed changes in the reflectance spectra after different stages of PSC oxidation.     

Therapist experience and the stresses of psychotherapeutic work.

A questionnaire survey of 227 licensed psychologists (aged 27–76 yrs) identified 5 stress factors associated with the nature of psychotherapeutic work (maintaining the therapeutic relationship, scheduling, professional doubt, overinvolvement, and personal depletion) and 5 associated with patient behaviors (negative affect, resistance, psychopathological symptoms, suicidal threats, and passive-aggressive behaviors). Less stress was reported by older Ss and those with moderate caseloads. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fimbriae of Bacteroides nodosus: protein engineering of the structural subunit for the production of an exogenous peptide

The pattern of sequence variation between Bacteroides nodosusfimbrial subuits of different serotypes suggests a degree offlexibility, which might be exploited for protein engineeringapproaches for the expression of other peptides. We have testedthis using the well-characterized peptide epitope from VP1 offoot-and-mouth disease virus (FMDV), residues 144–159:LRGDLQVLAQKVARTL (strain 01-BFS). Using bacterial codon usage,several oligonucleotides were designed for the substitutionof this sequence internally at hypervariable regions of thefimbrial subunit (aligned for maximum homology), and for itsaddition at the carboxy-terminus with a diglycine spacer asa flexible hinge. Following site-directed mutagenesis in phageM13, the modified genes were placed under P_L promoter controland placed in a broad host range vector. Analysis of the variantproteins expressed in E.coli showed that these substitutionsaffected, to varying extents, recognition by both anti-fimbrialand anti-FMDV antibodies, indicating that hypervariable region2 is a major antigenic determinant of the fimbrial subunit andthat local stereochemical effects can influence antibody bindingto the FMDV peptide antigenic determinant. In Pseudomonas aeruginosa,viable transformants could only be obtained with the mutantgene encoding the carboxy-terminal graft. These cells providedfimbrial preparations comprised of the modified subunit. Thisthen constitutes the prototype for the development of a generalexpression system for the production of vaccine epitopes andother bioactive peptides. Furthermore, there is considerablescope for further modification of the system, for example byengineering specific chemical or protease cleavage sites forrelease of the grafted peptide. Alternatively, the fimbriaethemselves may serve as a useful supramoleuclar carrier or adjuvantfor immune provocation.     

Narp regulates long-term aversive effects of morphine withdrawal.

Although long-lasting effects of drug withdrawal are thought to play a key role in motivating continued drug use, the mechanisms mediating this type of drug-induced plasticity are unclear. Because Narp is an immediate early gene product that is secreted at synaptic sites and binds to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, it has been implicated in mediating enduring forms of synaptic plasticity. In previous studies, the authors found that Narp is selectively induced by morphine withdrawal in the extended amygdala, a group of limbic nuclei that mediate aversive behavioral responses. Accordingly, in this study, the authors evaluate whether long-term aversive effects of morphine withdrawal are altered in Narp knockout (KO) mice. The authors found that acute physical signs of morphine withdrawal are unaffected by Narp deletion. However, Narp KO mice acquire and sustain more aversive responses to the environment conditioned with morphine withdrawal than do wild type (WT) controls. Paradoxically, Narp KO mice undergo accelerated extinction of this heightened aversive response. Taken together, these studies suggest that Narp modulates both acquisition and extinction of aversive responses to morphine withdrawal and, therefore, may regulate plasticity processes underlying drug addiction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some future social repercussions of computers

The prehistory and history of computers and programs are briefly reviewed and are used as a basis for predicting the future. Computers are classified into thirteen generations of which the last five have not yet arrived. A previously published argument is mentioned suggesting that an ultra‐intelligent machine will be built within a few decades and its promise and dangers are emphasized. It is suggested that an association for dealing with the dangers should be started.

A proposal for press‐button peace is mentioned, based on computerized international cooperation. Numerous future applications for computers are briefly discussed, some being natural extrapolations from what has already begun.     

Cerebrosides alter the lyotropic and thermotropic phase transitions of DOPE:DOPC and DOPE:DOPC:sterol mixtures

An infectious cDNA of a highly myocarditic coxsackievirus B3 (CVB3m; Nancy strain) was cloned. Sequence data revealed 43 extra non-viral nucleotides upstream of the initial 5' sequence. However, the authentic 5' end sequence was maintained during replication of viral RNA transfected into HeLa cells, suggesting the RNA synthesizing complex edits the picornaviral 5' terminus sequence. Nucleotide sequences of the 5' nontranslated region and the capsid protein gene sequence of CVB3m were compared with the published sequences of five other CVB3 Nancy strains and two main lineages were found. In comparative assays for cardiovirulence, three of four CVB3 tested were cardiovirulent in adolescent male CD-1 mice. Only one of the three available CVB3 strains was neutralized with several anti-CVB3m monoclonal antibodies, suggesting that mutations in the surface epitopes of the capsid polypeptides contribute to antigenic drift within the serotype, perhaps in part through immunoselective pressures. Thus, phenotypic diversity of CVB3 within the prototype Nancy strain is an example of RNA viruses adapting to changing environments (cells, mice and humans) through mutations and selective pressure.