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[formula: see text] The convergent synthesis of the ABCDEF-ring system of yessotoxin and adriatoxin was accomplished. This efficient convergent strategy was performed on the basis of the coupling of the acetylide of the A-ring and the triflate of the DEF-ring, oxidation of the alkyne to diketone, intramolecular diacetalization, and stereoselective reduction of the diacetal with Et3SiH-TMSOTf.
[reaction: see text] A convergent synthetic route to the CDEFG-ring system of gambieric acids, potent antifungal polycyclic ether marine natural products, has been developed. The present synthesis features convergent union of the CD- and G-rings through esterification, formation of the E-ring as a lactone form, stereoselective allylation to set the C26 stereocenter, and ring-closing metathesis reaction to construct the nine-membered F-ring.
Few studies have evaluated Quality Of Life (QOL) among low-income patients with cancer. Information is needed about the feasibility and psychometric characteristics of QOL instruments in these populations. The purpose of this study was to examine the convergent and discriminant relationships between scales of three QOL instruments: European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC), Functional Assessment of Cancer Therapy--General (FACT), and Quality of Life Index (QLI). Participants included 110 men with metastatic prostate cancer of whom 94% were low income and 62% were African-American. Interviewers administered the questionnaires. Cronbach alpha internal consistency reliabilities were 0.57 to 0.90 for the EORTC, 0.65 to 0.86 for the FACT, and 0.63 for the QLI. Convergent validity was supported for the EORTC and FACT scales measuring emotional, physical, and role/functional dimensions (r = 0.54 to 0.72), but not on scales measuring social function (r = 0.12). Divergent validity was supported between dissimilar scales (r = 0.14 to 0.38). Analysis with receiver operating characteristics curves provided empirical support for the EORTC and FACT as multidimensional measures. These findings suggest that, even in busy clinical settings with low literacy patients, interviewer-administered EORTC and FACT QOL instruments can provide valid and reliable information.
Free Energy Perturbations (FEP) in the context of Monte Carlo (MC) simulations were conducted to predict the relative free energies of binding for a series of human Src SH2 domain ligands. Two procedures for disappearing atoms during a single-topology FEP are investigated and dramatic differences in free energy convergence behavior are seen. Comparison of these two protocols suggests that the coupling of the removal of angular constraints with the disappearance of an atom may significantly slow free energy convergence. The series of ligands under investigation here cover a range of modifications at the 3-position of 4-([[4-(cyclohexyl methoxy)benzyl]amino]carbonyl) phenyl phosphate. Unlike any other compound in this study, the 3-amide analog can form two hydrogen bonds within the region of the perturbation, one to a backbone amide hydrogen and one to a highly coordinated water molecule. Agreement with experimental trends in binding affinity is seen, although the computed relative free energy of binding of the amido compound is underestimated. These results are reconciled by examination of the hydration energies of model systems, which predict primary amides as too hydrophilic.
We examined the convergent validity of three posttraumatic symptoms inventories, the civilian version of the Mississippi Scale for Combat-Related PTSD (CM-PTSD), the Trauma Symptom Checklist-40 (TSC-40), and the Response to Childhood Incest Questionnaire (RCIQ), in a sample of 52 adult sexual abuse survivors. The significant and moderate to strong correlations (r = .6 or higher) among these inventories supported their convergent validity. Comparison with other studies also suggests that these instruments can adequately discriminate clinical from nonclinical populations.
We evaluated the validity of the Perinatal Posttraumatic Stress Disorder Questionnaire (PPQ) as a measure of posttraumatic stress symptomatology. Mothers of high-risk infants (N = 91) and healthy, full-term infants (N = 51) answered the PPQ and two other convergent measures of posttraumatic stress disorder symptoms, the Impact of Event Scale (IES) and the Penn Inventory (PI). The Need for Cognition Scale (NCS) was used as a divergent measure. Correlations among the convergent measures were significantly greater than the correlation between the PPQ and NCS. High-risk mothers also scored higher than normal mothers on the PPQ and IES. The results support the validity of the PPQ.
The binding of a set of 10 triphenoxypyridine derivatives to two serine proteases, factor Xa and trypsin, has been used to analyze factors related to sampling and convergence in free energy calculations based on molecular dynamics simulation techniques. The inhibitors investigated were initially proposed as part of the Critical Assessment of Techniques for Free Energy Evaluation (CATFEE) project for which no experimental results nor any assessment of the predictions submitted by various groups have ever been published. The inhibitors studied represent a severe challenge for explicit free energy calculations. The mutations from one compound to another involve up to 19 atoms, the creation and annihilation of net charge and several alternate binding modes. Nevertheless, we demonstrate that it is possible to obtain highly converged results (+/- 5-10 kJ/mol) even for such complex multi-atom mutations by simulating on a nanosecond time scale. This is achieved by using soft-core potentials to facilitate the creation and deletion of atoms and by a careful choice of mutation pathway. The results show that given modest computational resources, explicit free energy calculations can be successfully applied to realistic problems in drug design.
Drawing on recent criticism of the Implicit Association Test (IAT), the present study tested the convergent and discriminant validity of two prejudice-related IATs to corresponding explicit prejudice measures in a German student sample (N = 61). Confirming convergent validity, (a) an IAT designed to assess negative associations related to Turkish people was significantly related to the explicit endorsement of prejudiced beliefs about Turkish people, and (b) an IAT designed to assess negative associations related to East Asians was significantly related to explicit prejudice against East Asians. Moreover, confirming discriminant validity, (c) the Asian IAT was unrelated to the explicit endorsement of prejudiced beliefs about Turkish people, and (d) the Turkish IAT was unrelated to explicit prejudice against Asian people. These results further corroborate the assumption that the IAT is a valid method to assess the strength of evaluative associations in the domain of prejudice and stereotypes.
Acculturation, the process whereby immigrants change their behavior and attitudes toward those of the host society, is a fundamental part of migration-induced adaptations to new sociocultural environments. A rapidly expanding research literature on acculturation has accompanied the growth of international migrations. In response to the need to integrate the growing literature on acculturation and mental health status among Hispanics in the United States, and to identify points of convergence and new directions for research, 30 publications were examined. Points of convergence are identified, as are problems and limitations. The research needs new directions, proceeding from but not constricted by the assumptions and procedures in the work already done.
This study investigated the interrelationships, convergent and discriminant validity, and magnitude of racial differences on five Minnesota Multiphasic Personality Inventory (MMPI) alcohol scales and two drug scales with youthful samples (mean age = 22.3 years) of heavy and moderate alcohol users, heavy and moderate drug users, and non-psychoactive-substance-using inmates at a federal correctional institution (n = 1,048). Five scales showed some degree of convergent or discriminant validity. Racial differences were observed on five scales with blacks scoring lower on all these scales except one.
This study investigated the convergence of temperament dimensions with constructs from C. R. Cloninger's (1987a) theory using data from a sample of 949 adolescents (M age = 13.6 years). Substantial convergence was found, and both types of constructs were related in predicted ways to self-regulation variables and adolescent substance use. Structural modeling procedures tested a mediational model for substance use; results showed mediation through self-control, academic competence, negative life events, and deviant peer affiliations. Interactions indicated that substance use could be predicted from a balance of systems for good control and poor control. Poor self-control was present for dimensions implicated in both externalizing and internalizing disorders. Results are discussed with reference to self-regulation models of substance use and the comorbidity of substance abuse and mental disorder.
Previous studies have shown that the lateral nucleus of the amygdala (AL) is essential in auditory fear conditioning and that neurons in the AL respond to auditory stimuli. The goals of the present study were to determine whether neurons in the AL are also responsive to somatosensory stimuli and, if so, whether single neurons in the AL respond to both auditory and somatosensory stimulation. Single-unit activity was recorded in the AL in anesthetized rats during the presentation of acoustic (clicks) and somatosensory (footshock) stimuli. Neurons in the dorsal subdivision of the AL responded to both somatosensory and auditory stimuli, whereas neurons in the ventrolateral AL responded only to somatosensory stimuli and neurons in the ventromedial AL did not respond to either stimuli. These findings indicate that the dorsal AL is a site of auditory and somatosensory convergence and may therefore be a locus of convergence of conditioned and unconditioned stimuli in auditory fear conditioning.
This study used trait activation theory as a theoretical framework to conduct a large-scale test of the interactionist explanation of the convergent and discriminant validity findings obtained in assessment centers. Trait activation theory specifies the conditions in which cross-situationally consistent and inconsistent candidate performances are likely to occur. Results obtained by aggregating correlations across 30 multitrait-multimethod matrices supported the propositions of trait activation theory, shedding a more positive light on the construct validity puzzle in assessment centers. Overall, convergence among assessment center ratings was better between exercises that provided an opportunity to observe behavior related to the same trait, and discrimination among ratings within exercises was generally better for dimensions that were not expressions of the same underlying traits. Implications for assessment center research and practice are discussed.
The authors propose that people in relationships become emotionally similar over time--as this similarity would help coordinate the thoughts and behaviors of the relationship partners, increase their mutual understanding, and foster their social cohesion. Using laboratory procedures to induce and assess emotional response, the authors found that dating partners (Study 1) and college roommates (Studies 2 and 3) became more similar in their emotional responses over the course of a year. Further, relationship partners with less power made more of the change necessary for convergence to occur. Consistent with the proposed benefits of emotional similarity, relationships whose partners were more emotionally similar were more cohesive and less likely to dissolve. Discussion focuses on implications of emotional convergence and on potential mechanisms.
Two studies tested the effects of social motives during negotiation on postnegotiation group performance. In both experiments, a prosocial or a proself motivation was induced, and participants negotiated in 3-person groups about a joint market. In Experiment 1, groups subsequently performed an advertisement task. Consistent with the authors' predictions, results showed that proself groups performed worse on the convergent aspects of this task but better on the divergent aspects than prosocial groups. In Experiment 2, the authors manipulated social motive and negotiation (negotiation vs. no negotiation), and groups performed a creativity task (requiring divergent performance) or a planning task (requiring convergent performance). Proself groups showed greater dedication, functioned more effectively, and performed better than prosocial groups on the creativity task, whereas prosocial groups showed greater dedication, functioned more effectively, and performed better than proself groups on the planning task, and these effects only occurred when the task was preceded by group negotiation.
The present study investigated the convergent validity of the Gamblers' Beliefs Questionnaire (GBQ), Gambling Passion Scale (GPS), Eysenck Impulsivity Questionnaire (EIQ), and Stanford Time Perception Inventory (STPI) in reference to pathological gambling. The authors recruited 105 undergraduates representing categories of pathological gamblers, potential pathological gamblers, and nonpathological gamblers and administered the measures under neutral conditions. Both subscales of the GBQ and GPS and the Impulsivity subscale of the EIQ exhibited strong convergent validity, whereas the STPI showed weaker correspondence with symptoms of pathological gambling. Applications and limitations of these findings are discussed.
Convergent and divergent validity are critically important in developing psychological measures that reveal interpretable deficits in disordered populations. This article reports on 2 studies that evaluated the validity of context processing measures. In Experiment 1, a confirmatory factor analysis of data from 481 healthy adults established the convergent validity of 2 context processing measures and showed that context processing accounted for significant amounts of variance in standard IQ and working memory measures. In Experiment 2, 20 schizophrenia patients, 16 of their healthy siblings, and 28 controls were evaluated using a novel, short context processing measure, the dot pattern expectancy (DPX) task. The DPX was sensitive to specific deficits in schizophrenia patients and their healthy siblings. These findings support the construct validity of context processing measures, suggest context processing is a component of intellectual functioning, and demonstrate that brief context processing measures remain sensitive to psychopathological deficits.
To self-administer trains of pulse pairs, rats with electrodes in the hypothalamic reward system would press a lever at lower current thresholds or faster latencies, the shorter the intrapair interval--unless the interval was so short that each second pulse fell within the refractory period following the first. By delivering all second pulses to the contralateral reward system not only was this refractory period limitation on temporal summation circumvented but spatial summation of the two reward systems was demonstrated. Evidently, they converge somewhere upon common neurons. Nearby nonreward structures did not share in this convergence. Assuming that the temporal-summation decline at longer intrapair intervals reflected the course of transmitter disposal at the synapse, imipramine and diisopropylfluorophosphate were peripherally administered. These drugs, which retard disposal, respectively, in adrenergic and cholinergic synapses, indeed prolonged temporal summation, thus, supporting the assumption and implying that adrenergic and cholinergic mechanisms both mediate self-stimulation.