Gradient high-performance liquid chromatography of statistical and block copolymers of styrene and t-butyl methacrylate

Copolymers of styrene (S) and tert-butyl methacrylate (TBMA) containing 24–92 mass % of the latter monomer were investigated using a silica column with isooctane/tetrahydrofuran (THF) gradients and on a phenyl bonded-phase column by methanol (MeOH)/THF gradients using UV detection. In both cases, retention decreased with increasing TBMA content of the sample. This is in contrast to the behavior of copolymers of S and methyl methacrylate (MMA) whose retention in gradient elution on silica columns increases with MMA content due to the polarity of this unit. The inversion of elution order is a result of the bulky TBMA residues shielding the polar groups of the ester units. For copolymers of varying composition, the gradation in retention on retention on silica is quite sufficient for separating S/MMA but not for S/TBMA mixtures. The latter could be separated by composition on phenyl packings through MeOH/THF gradient elution. Block copolymers containing 80 or 92% TBMA could be baseline-separated. It was also possible to separate these samples from admixed PTBMA or PS homopolymers. Under the conditions used, the retention of a given block copolymer was somewhat higher than that of a statistical copolymer having the same composition. A block copolymer containing 80% TBMA was converted by transesterification into a S/MMA block copolymer. The elution of the latter fitted well in the sequence of S/MMA copolymers on silica column.     

Aggregate Queries Over Conditional Tables

Conditional tables have been identified long ago as a way to capture unknown or incomplete information. However, queries over conditional tables have never been allowed to involve column functions such as aggregates. In this paper, the theory of conditional tables is extended in this direction, and it is shown that a strong representation system exists which has the closure property that the result of an aggregate query over a conditional table can be again represented by a conditional table. It turns out, however, that the number of tuples in a conditional table representing the result of an aggregate query may grow exponentially in the number of variables in the table. This phenomenon is analyzed in detail, and tight upper and lower bounds concerning the number of tuples contained in the result of an aggregate query are given. Finally, representation techniques are sketched that approximate aggregation results in tables of reasonable size.     

Some Aspects of Reliability Growth

Reliability growth is examined with the use of a variant of the Duane model. This variant is based on stepwise growth and avoids some of the mathematical and philosophic dificulties associated with the Duane model. Monte Carlo simulation, while confirming the noisy behavior of reliability growth data, indicates that central tendencies are sufficiently strong to justify the use of Gaussian approximations for analysis of some aspects of growth. Some exact methods and some approximations for parameter estimation are presented.     

Introduction to EuroWordNet

This paper gives a global introduction to the aims and objectives of the EuroWordNet project, and it provides a general framework for the other papers in this volume. EuroWordNet is an EC project that develops a multilingual database with wordnets in several European languages, structured along the same lines as the Princeton WordNet. Each wordnet represents an autonomous structure of language-specific lexicalizations, which are interconnected via an Inter-Lingual-Index. The wordnets are built at different sites from existing resources, starting from a shared level of basic concepts and extended top-down. The results will be publicly available and will be tested in cross-language information retrieval applications.     

Highly sensitive thromboplastins do not improve INR precision

OBJECTIVE: Severe obesity (ie, at least 100% overweight or body mass index > or =40 kg/m2) is associated with significant morbidity and increased mortality. It is apparently becoming more common in this country. Conventional weight-loss treatments are usually ineffective for severe obesity and bariatric surgery is recommended as a treatment option. However, longitudinal data on the long-term outcome of bariatric surgery are sparse. Available data indicate that the outcome of bariatric surgery, although usually favorable in the short term, is variable and weight regain sometimes occurs at 2 years after surgery. The objective of this study is to present a review of the outcome of bariatric surgery in three areas: weight loss and improvement in health status, changes in eating behavior, and psychosocial adjustment. The study will also review how eating behavior, energy metabolism, and psychosocial functioning may affect the outcome of bariatric surgery. Suggestions for additional research in these areas are made. METHOD: Literature review. RESULTS: On average, most patients lose 60% of excess weight after gastric bypass and 40% after vertical banded gastroplasty. In about 30% of patients, weight regain occurs at 18 months to 2 years after surgery. Binge eating behavior, which is common among the morbidly obese, may recur after surgery and is associated with weight regain. Energy metabolism may affect the outcome of bariatric surgery, but it has not been systematically studied in this population. Presurgery psychosocial functioning does not seem to affect the outcome of surgery, and psychosocial outcome is generally encouraging over the short term, but there are reports of poor adjustment after weight loss, including alcohol abuse and suicide. CONCLUSIONS: Factors leading to poor outcome of bariatric surgery, such as binge eating and lowered energy metabolism, should be studied to improve patient selection and outcome. Long-term outcome data on psychosocial functioning are lacking. Longitudinal studies to examine the long-term outcome of bariatric surgery and the prognostic indicators are needed.     

Reliability and validity of the Parent-Child Relationship Inventory (PCRI): Evidence from a longitudinal cross-informant investigation.

Psychometric properties of the Parent-Child Relationship Inventory (PCRI) were examined using data collected from adolescents and their parents in the Fullerton Longitudinal Study. Results revealed acceptable internal consistency for most scales and moderate to high 1-year stability for all scales. Both parents' PCRI scores correlated with their views of family climate. Cross-informant concordance was pervasive and strong between mothers' PCRI scores and adolescents' perceptions of the parent-child relationship and family climate; however, convergence was not evident between fathers' and adolescents' reports. Additionally, poor performance was observed for the Autonomy scale. In conjunction with other research on parent-adolescent relationships, concerns are raised regarding the utility of scales to contrast mother-adolescent with father-adolescent relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Normative data for the MMPI-2 in child custody litigation.

Minnesota Multiphasic Personality Inventory–2 (MMPI-2) norms based on 508 child custody litigants are presented. Defensive underreporting and self-favorability were often exhibited along with an elevation on the Over-Controlled Hostility (O–H) scale. Highest mean clinical scale scores were Hysteria, Paranoia, and Psychopathic Deviate. Differences were not found among mothers, fathers, and stepparents, indicating that a single set of norms is suitable. Findings highlight the importance of context specificity in personality assessment. Proper interpretation of personality inventories in child custody disputes needs to consider both the norms of the standardization sample and the litigants' reference norms. It was not possible, to determine from the MMPI-2 per se whether a defensive approach overestimates mental health in a psychologically healthy population or conceals symptomatology in psychologically disturbed persons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunoglobulins and transient paraproteins in sera of patients with the Wiskott-Aldrich syndrome: a follow-up study

Immunoglobulin levels of individual classes and IgG subclasses and the occurrence of homogeneous immunoglobulins--paraproteins--were studied longitudinally in the sera of three patients with the Wiskott-Aldrich syndrome; Common findings in all three patients were great variations in the immunoglobulin levels, restricted heterogeneity of the immunoglobulins, the frequent appearance of transient homogeneous immunoglobulins and the presence of serum antibodies against bovine milk proteins. A partial and selective deficiency involving mainly the T immune system is postulated as an explanation for these findings.     

Sliding wear of an unlubricated frictional combination of ductile metal and brittle abrasive

The concept of determining wear from hypotheses concerning shear effects in metal surface regions was applied to the sliding wear of a smooth elastoplastically deformable metal substance and a rough brittle abrasive. Interfacial layers or lubricating depositions on either surface were neglected. The form of the contact was modelled using random fields for the roughness profiles. The resulting intensities of wear may be compared with published experimental results. The wear intensity level was quantitatively determined. Dependence on the nominal pressure and properties of the rough abrasive is thus explained. Instead of hardness the compressive strength of abrasive peaks is the dominant characteristic parameter.     

Analytical model of the blast wear intensity of metals based on a general arrangement for abrasive wear

The hypothesis that during the abrasive wear of metals the volume removed is proportional to the work of the shearing force in the surface region was used to derive an analytical arrangement for the intensity of blast wear in the stationary phase. Although the analysis is relatively general, the results are surprisingly clear. The analysis shows a good agreement with test results, explains some general tendencies of blast wear and illustrates the applicability of its hypotheses.