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PubMed1997

Social-Adaptive Functioning Evaluation (SAFE): a rating scale for geriatric psychiatric patients.

Geriatric chronic psychiatric inpatients often remain in a chronic psychiatric hospital because of serious deficits in adaptive life functions. Because the additional complications and adaptive changes associated with aging have not been considered in previous scales, the Social-Adaptive Functioning Evaluation (SAFE) was developed. The items in the scale measure social-interpersonal, instrumental, and life skills functioning and are designed to be rated by observation, caregiver contact, and interaction with the subject if possible. Interrater and test-retest reliability were examined (n = 60) and convergent and discriminant validity were rated against other relevant measures (n = 50) in separate studies, with all being found adequate. The factor structure of the scale was examined with exploratory factor analysis, revealing a three-factor structure. Finally, predictive validity was examined in a preliminary study of 140 patients, 45 of whom were discharged after the assessment. The results indicate that patients who remained hospitalized could be discriminated from those who were sent to nursing homes or community care on the basis of certain SAFE items and subscales. These results support the use of this instrument in later studies of geriatric psychiatric patients.

Activities of Daily Living↗
PubMed2005

Atlas-based anatomic labeling in neurodegenerative disease via structure-driven atlas warping.

A new method is presented for the automated anatomic labeling and comparative morphometric analysis of brain magnetic resonance imaging, warping a prelabeled atlas into congruence with the subject anatomy. The strategy emphasizes anatomically meaningful atlas deformations in the presence of strong degeneration and substantial morphologic differences, for example, cases with high levels of atrophy. The atlas deformation is not driven by image intensity similarities but by continuous anatomic correspondence maps, derived from individual presegmented brain structures. Automatically generated correspondence maps provide large sets of fiducials, driving a warp with many thousand degrees of freedom. Validation included a scan-rescan study and anatomically relevant self-validation in multiple sclerosis patients with substantial cortical and subcortical degeneration. The mean coefficient of variation in the scan-rescan study was 1.4%, with no significant difference in precision between normal and neurodegenerative anatomies. The self-validation demonstrated good structural overlap, with substantial improvement over established methods, such as Talairach spatial normalization.

Brain↗
PubMed2004

Psychometric evaluation of the behavioral inhibition/behavioral activation scales in a large sample of outpatients with anxiety and mood disorders.

The latent structure, reliability, and validity of the Behavioral Inhibition/Behavioral Activation Scales (BIS/BAS; C. L. Carver and T. L. White, 1994) were examined in a large sample of outpatients (N = 1,825) with anxiety and mood disorders. Four subsamples were used for exploratory and confirmatory factor analyses. In addition to generally upholding a latent structure found previously in nonclinical samples, results indicated measurement invariance of the BIS/BAS between genders and a higher order structure of the BAS scales. Convergent and discriminant validity of the BIS/BAS were supported by findings that the subscales correlated most strongly with measures of neighboring personality constructs (e.g., BIS with neuroticism, BAS with positive affect) than with measures of current anxiety and depression symptoms. Overall, the results support the psychometric properties of the BIS/BAS in this clinical sample.

Adolescent↗
PubMed1999

[Use of a structured diagnostic interview to identify depressive episodes in an epidemiologic study: a posteriori internal validation].

BACKGROUND: During these last years, many structured and standardized diagnostic interviews have been developed in order to identify psychiatric disorders in a standardized way. These tools enable a systematic investigation of these disorders according to international classifications. Their main drawback is to be long. To assess the care of depression, we used a shorter and more simple tool: the Mini International Neuropsychiatric Interview (MINI) to identify depressive subjects. METHOD: The study was conducted in the Gazel cohort from the French National Electricity and Gas Company. A stratified sample of 2394 civil servants selected in order to over-represent depressive subjects was asked to answer to the MINI interview through a phone interview. An epidemiological and statistical analysis was performed to test the MINI internal validity: prevalence of depressive disorders using different threshold of diagnosis (number of symptoms required to identify someone as depressive), frequency of different symptoms, variability between investigators and potential biases. RESULTS: Respondents to the phone interview (1108 civil servants) had more often presented depression markers for the last 5 years. Prevalence of depressive episodes changed little when we varied the threshold of diagnosis and did not stress any threshold problem. The variability between investigators was important, but the estimation of prevalence remained stable when we excluded extreme rates of prevalence. The choice of a classification system affected the prevalence estimation. Using the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) from the American Psychiatric Association, the prevalence of depressive episodes was lower and closer to the estimations shown in the literature than using the International Classification of Disease (ICD 10). Moreover, the stratification assigned very unbalanced weights to the stratification strata. By excluding depressive episodes observed in the stratum "control" (no depression "marker" from 1989 to 1994 in the database), the prevalence was very lower, whatever the classification was. Finally, factors which appeared linked to care of depression with the ICD definition remained the same when the DSM diagnosis definition was used, and relative risks were quite similar. CONCLUSION: The MINI appears to be a short and simple tool, suited to the epidemiological studies. This analysis does not highlight any failure in the internal consistency of the MINI. The remaining question is what the MINI really measures, particularly comparing to a psychiatrist's diagnosis.

Cross-Sectional Studies↗
PubMed1999

Comparison of the crystal and solution structures of two RNA oligonucleotides.

Until recently, there were no examples of RNAs whose structures had been determined by both NMR and x-ray crystallography, and thus there was no experimental basis for assessing the accuracy of RNA solution structures. A comparison of the solution and the crystal structures of two RNAs is presented, which demonstrates that NMR can produce solution structures that resemble crystal structures and thus validates the application to RNA of a methodology developed initially for the determination of protein conformations. Models for RNA solution structures are appreciably affected by the parameters used for their refinement that describe intramolecular interactions. For the RNAs of interest here, the more realistic those parameters, the greater the similarity between solution structures and crystal structures.

Base Sequence↗
PubMed2005

Evolution of the properties of Al(n)N(n) clusters with size.

A global optimization of stoichiometric (AlN)(n) clusters (n = 1-25, 30, 35, ..., 95, 100) has been performed using the basin-hopping (BH) method and describing the interactions with simple and yet realistic interatomic potentials. The results for the smaller isomers agree with those of previous electronic structure calculations, thus validating the present scheme. The lowest-energy isomers found can be classified in three different categories according to their structural motifs: (i) small clusters (n = 2-5), with planar ring structures and 2-fold coordination, (ii) medium clusters (n = 6-40), where a competition between stacked rings and globular-like empty cages exists, and (iii) large clusters (n > 40), large enough to mix different elements of the previous stage. All the atoms in small and medium-sized clusters are in the surface, while large clusters start to display interior atoms. Large clusters display a competition between tetrahedral and octahedral-like features: the former lead to a lower energy interior in the cluster, while the latter allow for surface terminations with a lower energy. All of the properties studied present different regimes according to the above classification. It is of particular interest that the local properties of the interior atoms do converge to the bulk limit. The isomers with n = 6 and 12 are specially stable with respect to the gain or loss of AlN molecules.

Journal Article↗
PubMed2000

Tryptophanyl fluorescence lifetime distribution of hyperthermophilic beta-glycosidase from molecular dynamics simulation: a comparison with the experimental data.

A molecular dynamics simulation approach has been utilized to understand the unusual fluorescence emission decay observed for beta-glycosidase from the hyperthermophilic bacterium Solfolobus sulfotaricus (Sbeta gly), a tetrameric enzyme containing 17 tryptophanyl residues for each subunit. The tryptophanyl emission decay of Sbeta gly results from a bimodal distribution of fluorescence lifetimes with a short-lived component centered at 2.5 ns and a long-lived one at 7.4 ns (Bismuto E, Nucci R, Rossi M, Irace G, 1999, Proteins 27:71-79). From the examination of the trajectories of the side chains capable of causing intramolecular quenching for each tryptophan microenvironment and using a modified Stern-Volmer model for the emission quenching processes, we calculated the fluorescence lifetime for each tryptophanyl residue of Sbeta gly at two different temperatures, i.e., 300 and 365 K. The highest temperature was chosen because in this condition Sbeta gly evidences a maximum in its catalytic activity and is stable for a very long time. The calculated lifetime distributions overlap those experimentally determined. Moreover, the majority of trytptophanyl residues having longer lifetimes correspond to those originally identified by inspection of the crystallographic structure. The tryptophanyl lifetimes appear to be a complex function of several variables, such as microenvironment viscosity, solvent accessibility, the chemical structure of quencher side chains, and side-chain dynamics. The lifetime calculation by MD simulation can be used to validate a predicted structure by comparing the theoretical data with the experimental fluorescence decay results.

Fluorescence↗
PubMed2003

Stabilization of polar ZnO surfaces: validating microscopic models by using CO as a probe molecule.

The determination of the structure of inhomogeneous metal-oxide surfaces represents a formidable task. With the present study, we demonstrate that using the binding energy of a probe molecule, CO, is a reliable tool to validate structural models for such complex surfaces. Combining several types of first-principles calculations with advanced molecular beam methods, we are able to provide conclusive evidence that the polar O-terminated surface of ZnO is either reconstructed or hydrogen covered. This finding has important consequences for the ongoing discussion regarding the stabilization mechanism of the electrostatically unstable ("Tasker type 3") polar ZnO surfaces.

Journal Article↗
PubMed2001

Well-being of intensive care nurses (WEBIC): a job analytic approach.

AIMS OF THE STUDY: This paper presents the results of a validation study of the so-called well-being of intensive care nurses (WEBIC)-questionnaire that is designed to perform a detailed job analysis of intensive care unit (ICU) nurses' jobs. BACKGROUND: The WEBIC-questionnaire is based on modern sociotechnical systems theory, and distinguishes four integrated task categories: (1) operational, (2) organizing, (3) preparatory, and (4) supportive tasks. For each task, the WEBIC assesses (1) how demanding this task is, and (2) how satisfying the performance of this task is. Using the WEBIC, information is gathered about ICU nurses' qualitative workload, and typical job-related risks for ICU nurses' well-being at work can be mapped. METHODS: A cross-sectional survey on work and well-being of almost 2000 ICU-nurses in 13 different European areas was conducted. Exploratory factor analyses were performed to study the validity of the factorial structure of the WEBIC-questionnaire. The construct validity of the WEBIC-questionnaire was studied by performing hierarchical multiple regression analyses of the WEBIC-factors on two types of job-related well-being, i.e. burnout and general job satisfaction. RESULTS: Results of the exploratory factor analyses showed that the hypothesized four-factor structure of the WEBIC is confirmed by our data. Internal consistencies of the different factors varied from 0.77 to 0.91. Intensive care unit nurses' most central (operational) tasks turned out to pose the greatest demands, but also seemed to drive their satisfaction. With respect to the relationships between the four WEBIC-factors, and burnout and general job satisfaction, it was found that, especially for the satisfying tasks, significant relationships with these outcomes were found. CONCLUSION: The reliability and construct validity of the WEBIC-questionnaire can be considered satisfactory. Furthermore, the questionnaire provides a systematical and detailed coverage of ICU nurses' tasks. In relation to this, the questionnaire is not only useful for scientific purposes but also for practical use.

Adult↗
PubMed2002

Predictive validity and estimated cut score of an objective structured clinical examination (OSCE) used as an assessment of clinical skills at the end of the first clinical year.

BACKGROUND: Assessment plays a key role in the learning process. The validity of any given assessment tool should ideally be established. If an assessment is to act as a guide to future teaching and learning then its predictive validity must be established. AIM: To assess the ability of an objective structured clinical examination (OSCE) taken at the end of the first clinical year of an undergraduate medical degree to predict later performance in clinical examinations. METHODS: Performance of two consecutive cohorts of year 3 medical undergraduates (n=138 and n=128) in a 23 station OSCE were compared with their performance in 5 subsequent clinical examinations in years 4 and 5 of the course. RESULTS: Poor performance in the OSCE was strongly associated with later poor performance in other clinical examinations. Students in the lowest three deciles of OSCE performance were 6 times more likely to fail another clinical examination. Receiver operating characteristic curves were constructed as a method to criterion reference the cut point for future examinations. CONCLUSION: Performance in an OSCE taken early in the clinical course strongly predicts later clinical performance. Assessing subsequent student performance is a powerful tool for assessing examination validity. The use of ROC curves represents a novel method for determining future criterion referenced examination cut points.

Clinical Competence↗
PubMed1992

Molecular conformation of ubiquitinated structures and the implications for regulatory function.

The molecular conformation of ubiquitinated structures and the validity of the N-end rule were examined by simulating the molecular mechanics to ascertain the global energy-minimized structure. We examined the chemical linkage involved in attaching the ubiquitin carboxyl terminus to the N-terminus of three different x-hexapeptides, where x is the amino group of the acceptor peptide--either valine, arginine or glutamic acid--(x-K linkage) and to the epsilon-amino group of lysine of the acceptor hexapeptide x-glu1-his2-lys3-gly4-lys5-val6 (K-K linkage) through the formation of an isopeptide bond. Changes in conformation and molecular stability of the multi-ubiquitinated structures were determined by energy-minimization procedures using the SYBYL program developed by Tripos Associates. In the x-K linkage, the ubiquitin molecule is stretched in the beta-pleated sheets and beta-turns while the alpha-helices expand, as the molecule continues to unfold linearly. In the K-K linkage, the ubiquitin molecules have turned into a u-shaped, semi-circular alignment, contracting into a compact, folded structure.

Amino Acid Sequence↗
PubMed1998

Why discourse structures in medical reports matter for the validity of automatically generated text knowledge bases.

The automatic analysis of medical full-texts currently suffers from neglecting text coherence phenomena such as reference relations between discourse units. This has unwarranted effects on the description adequacy of medical knowledge bases automatically generated from texts. The resulting representation bias can be characterized in terms of artificially fragmented, incomplete and invalid knowledge structures. We discuss three types of textual phenomena (pronominal and nominal anaphora, as well as textual ellipsis) and outline basic methodologies how to deal with them.

Artificial Intelligence↗
PubMedDate not supplied

Psychometric evaluation of the marijuana and stimulant effect expectancy questionnaires for adolescents.

Alcohol expectancies are important in the mediation and prediction of alcohol use. Expectancies for the effects of other drugs, although less well delineated, appear equally important. Therefore, development and validation of expectancy measures for drugs other than alcohol is necessary for evaluating the importance of these constructs. We examined the factor structure, reliability, and validity of the Marijuana Effect Expectancy Questionnaire (MEEQ) and the Stimulant Effect Expectancy Questionnaire (SEEQ) in clinical and community samples of adolescents as they moved into young adulthood (N=279). Confirmatory factor analyses (CFAs) supported the a priori factors, and we found good reliability for most individual scales. Temporal stability and convergent and discriminant validity of drug effect expectancies were supported in this sample of adolescents and young adults. Drug effect expectancies were associated with drug preference and drug use patterns over 2 years. Use of these measures may aid our understanding of the etiology and course of marijuana and stimulant involvement during adolescence and young adulthood.

Adolescent↗
PubMed1991

Factor structure of the Motivation Assessment Scale for persons with mental retardation.

The rating scale used to assess the motivators of maladaptive behaviors in persons with mental retardation was the Motivation Assessment Scale. In the current study, we validated the factor structure of the scale on a sample of 118 subjects with predominately severe or profound mental retardation. They exhibited deviant behaviors such as self-injurious and tantrum behavior, aggression, and passivity. The results of the factor analysis with varimax rotation validated the assumptions of the developers of the scale that the motivators could be grouped into sensory, escape, attention, and tangible reinforcers. These four subscales are easily interpretable and should continue to provide valuable information.

Adult↗
PubMed2005

Recognition and signal transduction mechanism of Escherichia coli heat-stable enterotoxin and its receptor, guanylate cyclase C.

Guanylate cyclase C (GC-C), a member of the membrane-bound GC family, consists of an extracellular domain (ECD) and an intracellular domain, which are connected by a single-transmembrane region. GC-C is a receptor protein, i.e. specifically stimulated by the endogenous peptides guanylin, uroguanylin, lymphoguanylin, and the exogenous peptide heat-stable enterotoxin (ST(a)), secreted by pathogenic Escherichia coli and acting on the intestinal brush border membranes. The binding of these peptide ligands to the ECD of GC-C results in the synthesis of cyclic GMP in cells, which, in turn, regulates a variety of intracellular physiologic processes. As the cloning of GC-C, its physiologic functions of each domain have been vigorously investigated. The structural characterization of the ligand-binding domain of the receptor promises to provide important clues for better understanding of the mechanisms of receptor recognition and activation. Recently, structural data for each domain of membrane-bound GCs and related proteins has become available. Coupling information obtained from such work and validation of structure-function relationships of GC-C and its ligands should allow for three-dimensional mapping of their interaction site in detail. Our approach to this issue involved designing photoaffinity-labeling ST(a) analogs, capable of binding covalently to the ligand-binding region of the ECD of GC-C. The photoaffinity-labeling ligand was used to covalently label a soluble form of the recombinant ECD protein. Mass spectrometric analyses of an endoproteinase digest of the ECD revealed that the ligand specifically bound to a narrow region contained in the membrane-proximal subdomain of the ECD of GC-C. These results will enable us to identify the possible binding motifs within the ligand-binding domain by computer modeling. In this review, we summarize the available data on the recognition mechanism between ST(a) and GC-C at the molecular level.

Amino Acid Sequence↗
PubMed1997

Development and validation of a computerized screening test for personality disorders in DSM-III-R.

The available self-report instruments designed to measure personality disorder (PD) are time-consuming to administer and/or score and can be impractical for routine clinical use. There is a need for a computerized method of personality assessment based on contemporary systems of classification. A computerized DSM-III-R-based questionnaire was developed and validated against the structured clinical interview for DSM-III-R Axis-II disorders on a sample of 60 subjects. The computerized test showed moderate validity as a diagnostic instrument (mean kappa coefficient = 0.47). With adjusted cut-off scores it was valid as a screening instrument (mean sensitivity = 0.87). Antisocial, borderline and avoidant PD scores were strongly correlated across measures and not subject to significant observer bias.

Adult↗
PubMed2002

Further development and validation of empirical scoring functions for structure-based binding affinity prediction.

New empirical scoring functions have been developed to estimate the binding affinity of a given protein-ligand complex with known three-dimensional structure. These scoring functions include terms accounting for van der Waals interaction, hydrogen bonding, deformation penalty, and hydrophobic effect. A special feature is that three different algorithms have been implemented to calculate the hydrophobic effect term, which results in three parallel scoring functions. All three scoring functions are calibrated through multivariate regression analysis of a set of 200 protein-ligand complexes and they reproduce the binding free energies of the entire training set with standard deviations of 2.2 kcal/mol, 2.1 kcal/mol, and 2.0 kcal/mol, respectively. These three scoring functions are further combined into a consensus scoring function, X-CSCORE. When tested on an independent set of 30 protein-ligand complexes. X-CSCORE is able to predict their binding free energies with a standard deviation of 2.2 kcal/mol. The potential application of X-CSCORE to molecular docking is also investigated. Our results show that this consensus scoring function improves the docking accuracy considerably when compared to the conventional force field computation used for molecular docking.

Binding Sites↗
PubMed2005

A psychometric evaluation of the Fagerström Test for Nicotine Dependence in PTSD smokers.

Rates of smoking among individuals with psychiatric conditions are greater than rates seen in the general population, yet little is known about the psychometric properties of commonly used nicotine dependence instruments among psychiatric smokers. This study examined the reliability, validity, and factor structure of the Fagerström Test for Nicotine Dependence (FTND) among psychiatric smokers. Results revealed that the FTND had good test-retest reliability, convergent validity, and discriminant validity. A factor-analytic examination converged on a two-factor solution, reflecting two correlated but separate processes related to nicotine dependence. In total, the results revealed that the FTND performs as well--from a psychometric perspective--with psychiatric smokers, as it does with nonpsychiatric smokers.

Female↗