Behavior in a nonexperiment: The effects of behavioral field research on the work performance of factory employees.

To determine whether a field research process itself has an influence on employee productivity which might become confounded with the influence of more legitimate independent variables, 73 male workers in 1 department of a factory were studied. Field research operations, consisting of observational and survey techniques, were employed during the middle 2 wk. of the 6-wk "before," "during," and "after" experimental design. Research effects on the total department and the 8 work groups were negligible. Hypothesized moderator influences for age, authoritarianism, rural-urban background and union activity level, although small, were found thus demonstrating that research operations can affect different people in different ways on a productivity criterion. (19 ref.) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Synthesis of dihydroperoxides of linoleic and linolenic acids and studies on their transformation to 4-hydroperoxynonenal

The cytotoxic aldehydes 4-hydroxynonenal, 4-hydroperoxynonenal (4-HPNE), and 4-oxononenal are formed during lipid peroxidation via oxidative transformation of the hydroxy or hydroperoxy precursor fatty acids, respectively. The mechanism of the carbon chain cleavage reaction leading to the aldehyde fragments is not known, but Hock-cleavage of a suitable dihydroperoxide derivative was implicated to account for the fragmentation [Schneider, C., Tallman, K.A., Porter, N.A., and Brash, A.R. (2001) Two Distinct Pathways of Formation of 4-Hydroxynonenal. Mechanisms of Nonenzymatic Transformation of the 9- and 13-Hydroperoxides of Linoleic Acid to 4-Hydroxyalkenals, J. Biol. Chem. 275, 20831–20838]. Both 8,13- and 10,13-dihydroperoxyoctadecadienoic acids (diHPODE) could serve as precursors in a Hock-cleavage leading to 4-HPNE via two different pathways. Here, we synthesized diastereomeric 9,12-, 10,12-, and 10,13-diHPODE using singlet oxidation of linoleic acid. 8,13-Dihydroperoxyoctadecatrienoic acid was synthesized by vitamin E-controlled autoxidation of γ-linolenic acid followed by reaction with soybean lipoxygenase. The transformation of these potential precursors to 4-HPNE was studied under conditions of autoxidation, hematin-, and acid-catalysis. In contrast to 9- or 13-HPODE, neither of the dihydroperoxides formed 4-HPNE on autoxidation (lipid film, 37°C), regardless of whether the free acid or the methyl ester derivative was used. Acid treatment of 10,13-diHPODE led to the expected formation of 4-HPNE as a significant product, in accord with a Hock-type cleavage reaction. We conclude that, although the suppression of 4-H(P)NE formation from monohydroperoxides by α-tocopherol indicates peroxyl radical reactions in the major route of carbon chain cleavage, the dihydroperoxides previously implicated are not intermediates in the autoxidative transformation of monohydroperoxy fatty acids to 4-HPNE and related aldehydes.     

Robert L'Hermite Medallist, 2005

RILEM Bulletin

Robert L'Hermite Medallist, 2005     

Identification of some of the polysilicate components of trimethylsilylated cement paste

Trimethylsilyl derivatives from polymerised silicate anions in an eight-year-old cement paste have been fractionated by high-pressure liquid chromatography (hplc) and the fractions examined by thin layer chromatography, mass spectrometry and infrared spectrometry. The hplc separates linear from cyclic species. The major low molecular weight silicate anion in the C-S-H larger than dimer appears to be the linear pentamer. The presence in small quantity, of both linear tetramer and cyclic pentamer has been confirmed and the identification of the two high-temperature gas-liquid chromatography peaks with those species is supported.     

Personality processes reflected in client vocal style and Rorschach performance.

Proposed vocal style as a useful variable with which to classify groups of clients in order to study the differential effects of various therapeutic maneuvers. Relationships between voice quality ratings in early psychotherapy interviews and pretherapy Rorschach and MMPI scores were investigated in order to explore the nature and generality of this variable. For 52 clients in time-limited, client-centered psychotherapy, significant relationships were found between 3 of the vocal styles and Rorschach variables developed to measure qualities commonly observed in creative individuals. Vocal styles were substantially unrelated to MMPI scores. Implications for differential prognosis are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

13C NMR Study of the Acid-Catalyzed Carbonylation of Methyl tert-Butyl Ether (MTBE)

Methyl tert-butyl ether (MTBE) is a widely used additive in oxygenated gasoline that has recently been identified as a potential health threat to the drinking water supply due to leaking underground storage tanks. One alternate use for MTBE is the production of methyl 2,2-dimethylpropanoate (methyl pivalate) via Koch carbonylation chemistry. BF₃/H₂O catalysts are employed in industrial applications of Koch chemistry, but cannot be used for direct ester production because the presence of water in the system leads to the formation of carboxylic acids and lowers the selectivity to esters. Therefore, a BF₃/CH₃OH complex was investigated for the carbonylation of MTBE to avoid this loss in selectivity. This study used ¹³C NMR spectroscopy and ab initio calculations to investigate this carbonylation reaction. NMR results and ab initio calculations suggest a structure for the BF₃/CH₃OH acid which is in agreement with previous studies, and a Hammett acidity value of -4.2 was calculated for BF₃-2.19CH₃OH using the method. It is believed that these are the first reported ab initio calculations on the BF₃/CH₃OH system. NMR results also show that MTBE begins to react between 50 °C and 75 °C to produce oligomers of isobutene when no CO is present and carbonylated species when CO is present.     

Thermal degradation of poly(methyl methacrylate) at 50°C to 125°C

Small but significant numbers of chain scissions occur in a commercial poly(methyl methacrylate) sheet exposed to temperatures between 50 and 125°C. The scission rate is initially high and then levels off to a constant rate. The short-time rate of chain scissions is temperature dependent, while the long-time rate of chain scissions appears to be temperature independent. Four possible sources of random chain scission initiation were considered: (1) the presence of unreacted initiators of polymerization, (2) free radicals generated from additives in the commercial film, (3) weak links in the polymer chain, and (4) free radicals generated from the thermal decomposition of an oxidation product of methyl methacrylate (MMA) monomer. The source most consistent with our results is the one involving free radicals generated from the oxidation product of MMA monomer.     

From composites to factors: Bridging the gap between PLS and covariance‐based structural equation modelling

Partial least squares (PLS) methods possess desirable characteristics that have led to their extensive use in the field of information systems, as well as many other fields, for path analyses with latent variables. Such variables are typically conceptualized as factors in structural equation modelling (SEM). In spite of their desirable characteristics, PLS methods suffer from a fundamental problem: Unlike covariance‐based SEM, they do not deal with factors, but with composites, and as such do not fully account for measurement error. This leads to biased parameters, even as sample sizes grow to infinity. Anchored on a new conceptual foundation, we discuss a method that builds on the consistent PLS technique and that estimates factors, fully accounting for measurement error. We provide evidence that this new method shares the property of statistical consistency with covariance‐based SEM but, like classic PLS methods, has greater statistical power. Moreover, our method provides correlation‐preserving estimates of the factors, which can be used in a variety of other tests. For readers interested in trying it, the new method is implemented in the software WarpPLS. Our detailed discussion should facilitate the implementation of the method in any numeric computing environment, including open source environments such as R and GNU Octave.     

Computation of through-space NMR shielding effects by aromatic ring-cation complexes: substantial synergistic effect of complexation

The HF-GIAO method in Gaussian 03 was employed to calculate the NMR isotropic shielding values of a diatomic hydrogen probe and to predict the through-space proton NMR shielding increment surfaces above benzene complexed with ammonium, lithium, sodium, potassium, magnesium or calcium ion. The sum of the calculated isotropic shielding values for the proximal hydrogen of a diatomic hydrogen probe over benzene and those calculated at appropriate positions relative to cations were subtracted from the isotropic shielding values calculated for the complexes. The result is a shielding increment for complexation. Complexation results in a synergistic effect on NMR shielding. Enhanced shielding was observed over the π electron cloud of benzene upon complexation with the cations, more than the sum of the separate effects of the aromatic ring and the charge. The results are interpreted in terms of polarization of the π cloud of benzene by the cation and its consequences.