An overview of FDA medical device regulation as it relates to deep brain stimulation devices.

The United States Food and Drug Administration (FDA) is charged with assuring the safety and effectiveness of a variety of medical products and the FDA's Center for Devices and Radiological Health is responsible for premarket and postmarket regulation of medical devices. In this paper, we review--from device classification and clinical studies to the final marketing application--FDA's premarket requirements and postmarket requirements as they relate to deep brain stimulation devices.     

Some nitrosoamino acids in bacon adipose tissue and their contribution to the total N-nitroso compound concentration

Zusammenfassung Der Gehalt an Nitrosoaminosäuren und ihr Anteil an den Gesamt-N-Nitrosoverbindungen im Fettgewebe von rohem Schinkenspeck wurde untersucht. In 80% der Proben wurde ein Gehalt an Nitrosoaminosäuren von bis zu 0,2 mg/kg festgestellt. Scheinbare Gesamt-N-Nitrosoverbindungen waren in allen Proben in einer Konzentration von 0,4 bis 3,7 mg (N-NO)/kg vorhanden. Die eigentlichen Nitrosoaminosäuren machen nur etwa 1% der scheinbaren Gesamt-N-Nitrosoverbindungen aus. Die Mehrzahl der scheinbaren Gesamt-N-Nitrosoverbindungen im Fettgewebe findet sich im nichtlöslichen Bindegewebe, wobei der verbleibende Rest chloroformlöslich ist.Summary The levels of nitrosoamino acids and apparent total N-nitroso compounds in the adipose tissue of raw bacon have been examined. Nitrosoamino acids were detected in 80% of the samples in levels of up to 0.2 mg/kg. Apparent total N-nitroso compounds were present in all samples in concentrations of between 0.4 and 3.7 mg (N-NO)/kg. Nitrosoamino acids accounted for approximately only 1 % of the apparent total N-nitroso compounds. The majority of the apparent total N-nitroso compounds in the adipose tissue were associated with the insoluble connective tissue fraction, with the remainder present as chloroform soluble species.

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Einige Nitrosoaminosäuren im fettgewebe von Schinkenspeck und ihr anteil an der Konzentration der Gesamt-N-Nitrosoverbindungen

     

Vers une méthodologie de validation trans-culturelle de questionnaires psychologiques: Implications pour la recherche en langue fran?aise.

Proposes a cross-cultural validation methodology that allows for the validation of French versions of English psychological scales. The 7 basic steps in the method are described: (1) preparation of a preliminary French version; (2) evaluation and modification of the preliminary version; (3) evaluation of the experimental French version in a pretest; (4) evaluation of content and concomitant validity; (5) evaluation of reliability; (6) evaluation of construct validity; and (7) preparation of norms for the French version. Examples of each step are presented. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Near-Optimal Signal Preprocessor for Positive Cardiac Arrhythmia Identification

Extremely high reliability of waveform detection is fundamental for computer-assisted identification of cardiac arrhythmias. The problem is formulated in terms of one of the basic aspects in digital signal processing, namely, detection of an unknown deterministic signal in noise. The signal is considered band limited and the noise as Gaussian with zero mean. The theory presented leads to an energy based detector. No a priori assumption is made about the morphology of the waveforms to be detected; only energy thresholding is necessary for event detection. The addition of a linear filter as a front end to the energy detector has resulted in an entire detection process described as suboptimal matched nonlinear filtering. The SNR gain at the input of the energy detector has given performances almost identical to the matched filter. The method has been implemented with an original fast algorithm to allow reasonable execution time for the processing of continuous long-duration signals (1 h). The design of such a fillter is described along with its application to the processing of two simultaneously recorded cardiac signals. The two signals are an auricular electrogram (OEG from an esophageal pill electrode) and an ECG (lead II or III). Systematic evaluation and detection performance results show that the proposed method could be seriously considered as a near-optimal approach to waveform detection, since it is based on proven signal processing theory and is far superior to heuristic methods.     

Effect of backward priming on word recognition in single-word and sentence contexts.

Backward priming was investigated under conditions similar to those used in lexical ambiguity research. Ss received prime-target word pairs that were associated either unidirectionally (BABY-STORK) or bidirectionally (BABY-CRY). In Exp 1, targets were presented 500 ms following the onset of visual primes, and Ss made naming or lexical decision responses to the targets. Forward priming was obtained in all conditions, while backward priming occurred only with lexical decision. In Exp 2, primes were presented auditorily, either in isolation or in a sentence. Targets followed the offset of the primes either immediately or after 200 ms. Backward priming occurred with both response tasks, but only when the prime was an isolated word. Backward priming decreased over time with the naming task, but not with lexical decision. These results suggest that the locus of the backward priming effect is different for the 2 response tasks. Results support a context-independent view of lexical access. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

POLARIZATION BEHAVIOR OF PACKED-BED ELECTRODES: A COMPARATIVE STUDY OF EXPERIMENTAL AND MODELING RESULTS

The current distribution and overall polarization behavior of electrodeposition at a flow-through (packed bed or fluidized bed) electrode are modeled by means of a one-dimensional model involving a primary reacting species and a simultaneous side reaction. The model equations are solved by orthogonal collocation; the time and storage requirements compare favorably to those of finite-difference methods. Experimental data obtained using a packed-bed electrode are compared with the model predictions and various methods of fitting the data are compared.     

Modification of alkenyl chain profile in plasmalogens of rat heart mitochondria by dietary trielaidin

Effects of dietary trielaidin upon the alkenyl chain profile of plasmalogens were studied using heart mitochondria of rats fed a semi-purified diet containing 10% of fat supplement in which elaidic acid accounted for 69% of total fatty acids. Alkyl substituted dioxane (ASD) derivatives of the alkenyl groups of plasmalogens were prepared and analyzed by silver nitrate TLC and by GLC on different phases (BDS and OV-275). After two months of feeding the experimental diet, 40% of the ASD contained atrans-octadecenyl chain, suggesting that dietary elaidic acid was reduced in vivo to the corresponding alcohol and incorporated into plasmalogens. There was a simultaneous decrease in the percentage of ASD containing saturated chains, but the percentage of ASD substituted withcis-octadecenyl chains was not significantly affected. These observations suggested that elaidic acid may compete with saturated fatty acids, but not withcis-octadecenoic acids during the plasmalogen biosynthesis. Feeding trielaidin did not seem to have any significant influence on the relative proportions of plasmalogens, which accounted for 11–12%, on a phosphorus basis, of total heart mitochondria phospholipids.     

Geometric criteria of hydrogen bonds in proteins and identification of `bifurcated' hydrogen bonds

Empirical criteria for identification of hydrogen bonds wereanalyzed to produce a set of geometrically consistent criteria.For a data set of 30 structures, application of a set of purelygeometrical criteria, along with exclusion of abnormal backboneconformations, also excluded a common interaction of Ser/Thrside chains with Asp/Glu side chains ([ST]/[DE] pairs). Theseinteractions were termed `bifurcated hydrogen bonds/', whichimplies delocalization of a positively charged hydrogen of hydroxylbetween the two acceptor atoms of the carboxylic group. These`bifurcated/' interactions are among the most common packingpatterns for [ST]/[DE] pairs of side chains. Therefore, theidentification of hydrogen bonds cannot be based on geometricalcriteria only and requires introduction of some physico-chemicalcriteria.     

L'échelle des Orientations Générales à la Causalité: Validation canadienne fran?aise du General Causality Orientations Scale.

Conducted a reliability and validity study of the French version of E. L. Deci and R. M. Ryan's (1985) General Causality Orientations Scale (GCOS), which measures the extent to which people are oriented toward the autonomy, control, and impersonal aspects of the initiation and regulation of behavior. Findings support the psychometric and construct validity of the French version of the GCOS; suggestions for its use in French-Canadian psychological research are discussed. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)