Electrodermal activity and social network as predictors of outcome of episodes in schizophrenia.

The predictive value of electrodermal activity and social network was examined among 48 consecutively admitted schizophrenic patients. The patients were followed from an initial admission, through hospital stay, discharge, follow-up (M?=?31 months), and possible relapse. Outcome variables were the length of stay in the hospital at the key episode and time to relapse, defined as a marked exacerbation or return of schizophrenic symptoms requiring inpatient or expansion of outpatient treatment. Multivariate analyses showed that a psychosocial variable, the availability of attachment, was the only independent predictor of length of stay in the hospital. Age at admission was a strong predictor of time to relapse. Age interacted with both outcome and electrodermal activity, and young electrodermal nonresponders were found to have the shortest time to relapse. At the l-year followup, a main relapse effect was found for patients with a low skin conductance level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biosensor-based determination of riboflavin in milk samples

An assay for quantification of riboflavin (Rf) in milk-based products has been developed using the principle of surface plasmon resonance with on-chip measurement. The quantification was done indirectly by measuring excess of Rf binding protein (RBP) that remains free after complexation with Rf molecules originally present in the sample solution. The chip was modified with covalently immobilized Rf in order to bind the RBP in excess. A chemical modification was performed to introduce a reactive ester group at the N-3 position of the natural Rf to bind amino groups present on the chip surface. Calibration solutions were prepared by mixing a range of Rf standard solutions with an optimized concentration of RBP. The Rf content in the milk-based products was then measured by comparison of the response against the calibration. Results obtained were very close to those from an official HPLC-fluorescence procedure. The limit of quantification was determined to 234 microg/L and the limit of detection to 70 microg/L by an injection volume of 160 microL.     

Lutetium speciation and toxicity in a microbial bioassay: testing the free-ion model for lanthanides

The validity of the free-ion model (FIM) for the element lutetium (Lu), a member of the lanthanides, was assessed in experiments with the bacterium Vibrio fischeri. The FIM is mainly based on divalent metals and synthetic ligands and has not yet been validated for the trivalent lanthanides. The bioluminescence response of V. fischeri was studied at different Lu concentrations in the presence and absence of natural and synthetic organic ligands [citrate, malate, oxalate, acetate, ethylenediaminetetraacetate (EDTA), and nitrilotriacetate (NTA)]. All ligands were tested separately to ensure that their concentrations would not cause adverse effects themselves. Free Lu3+ concentrations were calculated with a speciation program, after extension of its database with the relevant Lu equilibria. The results confirmed the FIM for Lu: that is, in contrast to total dissolved Lu concentrations, free Lu3+ concentrations had an apparent relationship with the response of V. fischeri. However, a contribution of minor inorganic Lu complexes cannot be ruled out. In the presence of malate and oxalate, the EC50 for Lu3+ decreased faster in time than for the other ligands, indicating lower elimination rates. With an EC50 of 1.57 microM, Lu3+ is more toxic than La3+, Cd2+, or Zn2+ and approximately equally as toxic as Cu2+. Although the pH increased slightly during the experiments, it was shown that the influence of pH on Lu speciation was limited.     

Solid-phase extraction NMR studies of chromatographic fractions of saponins from Quillaja saponaria

The saponin mixture QH-B from the tree Quillaja saponaria var. Molina was fractionated by RP-HPLC in several steps. The fractions were analyzed by solid-phase extraction NMR (SPE-NMR), a technique combining the workup by solid-phase extraction with on-line coupling to an NMR flow probe. Together with MALDI-TOF mass spectrometry and comparison with chemical shifts of similar saponins, the structures of both major and minor components in QH-B could be obtained. The procedure described is a simple method to determine the structure of components in a complex mixture. The two major fractions of the mixture were found to contain at least 28 saponins, differing in the carbohydrate substructures. Eight of these have not previously been determined. The 28 saponins formed 14 equilibrium pairs by the migration of an O-acyl group between two adjacent positions on a fucosyl residue.     

A result on the mean square error obtained using general tracking algorithms

Tracking time-varying properties is of crucial importance in all adaptive algorithms. In this contribution we study a fairly general algorithm for tracking properties of model parameters that can be described in a linear regression form (including AR models and the like). An explicit expression for the mean square error between the estimated and the true (time-varying) parameter is established. For slow adaptation this expression can be arbitrarily well approximated by a much simpler expression. The treatment differs from other related studies using weak convergence theory, averaging, etc. in that the results are not asymptotic in nature and are applicable also to the transient phase as well as over unbounded time intervals.     

Opinions and use of the DSM system by practicing psychologists.

Recent articles criticizing the new DSM-III have renewed discussion of the issues of diagnostic systems in general. A 4-page questionnaire was sent to 601 psychologists in the National Register of Health Service Providers, 1978 to assess their use of and views on the current and projected DSM systems. 434 (73.4%) were returned. Results suggest that diagnosis by DSM-II is used mainly as required by agencies and insurance companies. Little else seems to influence the use of DSM-II. It was also found that the development of an alternative American Psychological Association manual is contingent on acceptance by 3rd-party payers. Findings are discussed with regard to their impact on the future of diagnosis and psychology. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)