Nuclear-chemical synthesis of tritium-labeled phenyl-substituted picoline derivatives

Ion-molecule reactions of free phenyl cations with six-membered nitrogen-containing heterocyclic compounds: α-, β-, and γ-picolines, were studied. Phenyl cations were generated by tritium β-decay in double-labeled benzene. The mechanism of competing reactions of electrophilic addition to the nitrogen heteroatom in the ring and electrophilic substitution of the C-H bond in the pyridine ring was examined. The effect of methyl substituent in the pyridine molecule on the reaction pathway was evaluated. A one-step procedure for nuclear-chemical synthesis of tritium-labeled N-phenylpicolinium salts and phenyl-substituted picolines was developed.     

Distinctiveness and Correlation in Conceptual Structure: Behavioral and Computational Studies.

Patients with category-specific deficits have motivated a range of hypotheses about the structure of the conceptual system. One class of models claims that apparent category dissociations emerge from the internal structure of concepts rather than fractionation of the system into separate substores. This account claims that distinctive properties of concepts in the living domain are vulnerable because of their weak correlation with other features. Given the assumption that mutual activation among correlated properties produces faster activation in the normal system, the authors predicted a disadvantage for the distinctive features of living things for unimpaired adults. Results of a speeded feature verification study supported this prediction, as did a computational simulation in which networks mapped from orthography to semantics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microsatellite instability in follicle centre cell lymphoma

Fluorescent polymerase chain reaction (PCR) was used to assay 12 microsatellite markers (APC x 2, DCC, P53 x 2, RB1, NM23, WT1, D6S260, D6S262, D6S281 and TNFa) to look for evidence of microsatellite instability in 40 cases of follicle centre cell lymphoma (FCC). Evidence of novel alleles seen in the tumour tissue but not the normal uninvolved tissue was seen in seven cases (17%). In only two of these cases (5%) was more than one locus involved but in these cases multiple affected loci were seen (4/12 and 7/12 respectively). The detection of microsatellite instability indicates a DNA repair defect such as that which would be predicted to occur in cells with mutated mismatch repair genes, a novel finding in FCC lymphoma.     

A review of bacteriological culture of removed intrauterine contraceptive devices

The management of pain in patients with burn wounds is complex and problematic. Burn-wound pain is severe, inconsistent and underestimated. Patients experience severe pain, especially during procedures, until wound healing has occurred. A multi-modality approach is needed for effective management of pain, which requires an understanding of the mechanisms of pain. Altered pharmacokinetics and pharmacodynamics in burn-wound patients makes drug actions unpredictable. Opioids alone are seldom sufficient for pain control. The multi-modality approach includes the use of opioids and non-steroidal anti-inflammatory, anxiolytic and alternative drugs. Ketamine has been found to be a useful agent for analgesia in burn-wound patients; a dose of 10 mg/kg qid per os was found to be an effective adjunct to pain therapy.     

Extending trouble ticket systems to fault diagnostics

Network management in large heterogeneous communication environments requires the incorporation of more advanced tools than are currently available, especially in the area of fault management. By providing an informational infrastructure for documenting network behavior and maintenance activities, TTSs (trouble ticket systems) have provided some relief for the fault management problem. Researchers have recognized TTSs as a means for realizing more advanced functions in network management platforms to effect automatic trouble ticket generation, fault diagnostics, and the correlation of multiple views network problems and behavior. The authors describe current research trends towards understanding and implementing these advanced functions in a TTS framework     

Silicon-substrate microelectrode arrays for parallel recording ofneural activity in peripheral and cranial nerves

A new process for the fabrication of regeneration microelectrode arrays for peripheral and cranial nerve applications is presented. This type of array is implanted between the severed ends of nerves, the axons of which regenerate through via holes in the silicon and are thereafter held fixed with respect to the microelectrodes. The process described is designed for compatibility with industry-standard CMOS or BiCMOS processes (it does not involve high-temperature process steps nor heavily-doped etch-stop layers), and provides a thin membrane for the via holes, surrounded by a thick silicon supporting rim. Many basic questions remain regarding the optimum via hole and microelectrode geometries in terms of both biological and electrical performance of the implants, and therefore passive versions were fabricated as tools for addressing these issues in on-going work. Versions of the devices were implanted in the rat peroneal nerve and in the frog auditory nerve. In both cases, regeneration was verified histologically and it was observed that the regenerated nerves had reorganized into microfascicles containing both myelinated and unmyelinated axons and corresponding to the grid pattern of the via holes. These microelectrode arrays were shown to allow the recording of action potential signals in both the peripheral and cranial nerve settings, from several microelectrodes in parallel     

An 80-Msample/s video switched-capacitor filter using a parallelbiquadratic structure

This paper describes a fifth-order, low-pass switched capacitor filter for video applications. It has a 4-MHz cutoff frequency and uses a parallel biquadratic structure with double sampling to achieve an 80-MHz input sampling rate in a 2-μm CMOS process. The prototype filter is fully differential, occupies an active area of 11 mm² , and dissipates 190 mW     

Early detection of ageing in solder joints through laser probe thermal analysis of the peltier effect

We have recently developed an optical contactless method for testing the quality of solder joints during accelerated thermal cycling ageing processes.¹ The method was based upon the measurement of the dynamic thermal behaviour of the joint to short bursts of Joule heating. It has proved to be efficient in revealing the formation of cracks at the lead-solder interface. We present a method to evaluate ageing at a much earlier stage in the cycling process. We have observed in earlier work,¹ that before cracks appear, structural changes occur in the solder at the lead-solder interface. The thermal response of the solder joint is recorded over time to a Peltier heat perturbation produced by flowing a current pulse through the interface where structural changes occur. The key point in this method is to discriminate the Peltier effect from the Joule thermal response because both effects generate heat. The variation of the early Peltier response in the thermal cycling ageing tests is seen as a quantitative signature of the structural changes in the lead-solder interface.