Effect of organic acids on the mechanical properties of phenolic resin composites

The effect of salicylic acid and its derivatives on the properties of phenolic resin composites was evaluated. The composites were reinforced with aluminum oxide particles in both solid and hollow forms. Differential scanning calorimetry studies have shown that the reaction rate of phenolic resin was accelerated by salicylic acid, but was not affected by the other compounds. Salicylic acid also reduced the flexural strengths of the phenolic resin composites. The strength was decreased by more than 30% in comparison to that with no acid added. In contrast, two derivatives of this acid—sodium salicylate and 4‐hydroxybenzoic acid—have minimal impact on the flexural strengths of the composites. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 642–647, 2000     

Microbial synthesis of chiral intermediates for β-3-receptor agonists

Chiral intermediates were prepared by biocatalytic processes for the chemical synthesis of β-3-receptor agonists. These include: (i) the microbial reduction of 4-benzyloxy-3-methanesulfonylamino-2′-bromoacetophenone 1 to the corresponding (R)-alcohol 2 by Spingomonas paucimobilis SC 16113. In the biotransformation process, a reaction yield of >85% and an optical purity of 99.5% were obtained for the desired (R)-alcohol 2; (ii) the enzymatic resolution of racemic α-methyl phenylalanine amide, 3, and α-methyl-4-hydroxy-phenylalanine amide, 5, by amidase from Mycobacterium neoaurum ATCC 25795 to prepare the corresponding (S)-amino acids 4 and 6. Reaction yields of 49.9 and 49 M% (theoretical maximum yield 50 M%) and optical purities of 99 and 94% were obtained for the desired (S)-amino acids 4 and 6, respectively; (iii) the asymmetric hydrolysis of methyl-(4-methoxyphenyl)-propanedioic acid, ethyl diester, 7, to the corresponding (S)-monoester 8 by pig liver esterase. A reaction yield of 96 M% and an optical purity of 96% were obtained for (S)-monoester 8 when reactions were carried out in a biphasic system containing 10% ethanol at 10°C.     

Poisoning and Regeneration of an Ni/SiO2 Catalyst

The poisoning effect of thiophene during the hydrogenation of styrene on an Ni/SiO₂ catalyst, and the regenerating role of both pure hydrogen and 2-butyne in the presence of hydrogen on the poisoned catalyst, were studied. The treatments induced the elimination of sulfur and promoted an important recovery of the catalytic activity and selectivity. XPS analyses show that the sulfur species adsorbed during the catalyst poisoning is thiophene. Part of the sulfur remained irreversibly adsorbed after the regeneration treatments carried out at 473 K; a modification on the adsorbed sulfur electronic state was detected, which can be ascribed to thiophene hydrogenolysis induced by the regenerating temperature. © 1997 SCI.     

Magnesia-ammonium phosphate-bonded cordierite refractory castables: Phase evolution on heating and mechanical properties

A cordierite refractory castable was developed using the MgO-NH₄H₂PO₄ reaction. This castable was made with cordierite-mullite aggregates from scrap refractory material and a cement paste based on magnesia, calcined alumina, silica fume, and ammonium dihydrogen phosphate, which forms cordierite (2MgO·2Al₂O₃·5SiO₂) during heating at high temperature. The mix with water was cast into steel molds; the cold setting occurs within 30 min. The set castables were thermally treated and the evolution of the phases was observed. Struvite (NH₄·MgPO₄·6H₂O) was identified at room temperature; between 110 and 750 °C, the present phosphates were amorphous to X-ray diffraction (XRD). At 1100 °C, magnesium orthophosphate (Mg₃(PO₄)₂) and aluminum orthophosphate (AlPO₄) were present. At 1350 °C, the main crystalline phases were cordierite and mullite. Cold and hot flexural strength, thermal shock resistance, and physical properties were measured. The properties of magnesia-phosphate-bonded cordierite castables were compared with cordierite material obtained by conventional slip-casting method from aggregates, clay, talc, and calcined alumina.     

Review of La vie quotidienne du malade d'Alzheimer.

Reviews the book, La vie quotidienne du malade d'Alzheimer by Mitra Khosravi (2006). The objective of this book is to present the experiences of caregivers looking after patients with Alzheimer's disease. The author discusses the consequences upon daily life of the Alzheimer's diagnosis that are not usually anticipated by caregivers. Whereas the greatest part of the existing research relates to the immediate symptoms and the long-term results of Alzheimer's disease, Khosravi focuses on the caregivers. The book describes the principal difficulties involving the lack of information on the nature of the disease and the negligent psychological state of the patient. According to the author, the identification of physical and psychological limits is essential to avoiding complications and improving the quality of life Alzheimer's patients and their caregivers. This book is ideal for families and caregivers who face the long process of providing care for those afflicted with this "multiple system" disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of age at puberty on spatial ability in girls: A question of mechanism.

Tested 2 hypotheses related to the finding of D. P. Waber (see record 1977-20876-001) that late maturers of both sexes perform better on measures of spatial ability than early maturers do. Waber hypothesized that this phenomenon is related to hemispheric organization of cognitive functions. An alternative hypothesis is that the differences are related to psychosocial correlates of timing of puberty. These hypotheses were evaluated by measuring pubertal status; spatial ability; patterns of functional hemispheric specialization, as assessed by a dichhaptic task; participation in spatial activities; and masculine and feminine personality traits and interests in 85 11-yr-old girls. Results indicate that (a) spatial ability was positively correlated with later maturation; (b) spatial ability was positively correlated with masculine personality traits, masculine intellectual interests in the ideal self, and wanting to be a boy; (c) later maturation was positively correlated with the Femininity Scale of the California Psychological Inventory and negatively correlated with participation in 22 spatial activities; and (d) performance on the dichhaptic task was not correlated with either timing of puberty or spatial ability. Regression analyses indicated that masculinity variables and maturation rate had independent associations with spatial ability. It is suggested that both factors could be sources of sex differences in spatial ability. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In vitro antioxidant and anti-inflammatory effects of brewers' spent grain protein rich isolate and its associated hydrolysates

Brewers' spent grain (BSG) is a protein-rich by-product of the brewing industry. The present study examined the in vitro bioactivity of a BSG protein enriched preparation and its associated enzymatic hydrolysates (assigned A–J). Cytotoxicity was measured using the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MTT assay in U937 and Jurkat T cells. IC₅₀ values were lower in the U937 cell line, ranging from 4.93 to 9.27% v/v versus a range of 4.11% v/v to undetectable in Jurkat T cells. The superoxide dismutase (SOD) and comet assays were performed on U937 cells pre-incubated with test samples and subsequently exposed to an oxidant. Hydrogen peroxide (H₂O₂) significantly reduced SOD activity by 37.7% and none of the test samples provided protection. None of the samples protected against DNA damage induced by tert-butylhydroperoxide (t-BOOH); hydrolysate H, prepared with Alcalase at 60 °C, protected against H₂O₂-induced DNA damage. The total phenolic content (TPC) was found to range from 0.021 to 0.055 mg GAE/mg dry powder. The effect of the BSG-derived test samples on cytokine production (IL-2, IL-4, IL-10, IFN-γ) in Concanavalin A (conA) stimulated Jurkat T cells was measured using an enzyme linked immunosorbent assay (ELISA). The samples had no effect on IL-2 and IL-4 production. The unhydrolysed sample C significantly reduced IL-10, while the protein rich isolate, unhydrolysed control samples and hydrolysates D, E, F, and J significantly reduced IFN-γ production. The BSG preparations possess little antioxidant potential and exhibit selective immunomodulatory effects that may be of benefit in the control of inflammatory diseases.     

Enhancing building, conversation, and learning through caregiver–child interactions in a children’s museum.

The authors adapted an experimental design to examine effects of instruction prior to entry into a children’s museum exhibit on caregiver–child interactions and children’s learning. One hundred twenty-one children (mean age = 6.6 years) and their caregivers were randomly assigned to 1 of 5 conditions that varied according to what, if any, preexhibit instruction the dyads received: (a) building and conversation instruction, (b) building instruction only, (c) conversation instruction only, (d) presentation of models of buildings and conversations without instruction, or (e) no instruction or control. Building instruction included information about triangular cross-bracing. Conversation instruction emphasized the use of elaborative wh-questions and associations. When observed in the exhibit, dyads in the groups that received building instruction included more triangles in their structures than those in the other groups. Caregivers provided with conversation instruction asked more wh-questions, made more associations, and engaged in more caregiver–child joint talk compared with those who received building instruction alone. Type of instruction was further linked to differences across conditions in the engineering content of talk, performance during immediate assessments of learning, and children’s memory following 1-day and 2-week delays. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of speech style and sex of speaker on person perception.

R. T. Lakoff (1975) has suggested that men and women use different speech styles, with women's speech more polite but less assertive than men's. The assumption that 3 of Lakoff's linguistic variables (tag questions, qualifiers, and compound requests) affect person perception in these ways was tested. Sex of speaker was also varied. In Exp I, 80 undergraduates rated the assertiveness, warmth, and politeness of 2 male and 2 female speakers who used or did not use the 3 linguistic forms. All 3 "female" linguistic forms were rated less assertive than corresponding "male" forms; qualified speech and compound requests were rated warmer and compound requests more polite. Sex of speaker was a significant factor in only one possible comparison. These results were substantially replicated in Exp II, in which older and/or less educated women (32 18–58 yr olds) acted as judges. Findings suggest that Lakoff's intuitions concerning effects of speech styles on person perception are largely correct and that modification of speech styles could allow men and women to affect how they are perceived. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)