Satiety-responsive neurons in the medial orbitofrontal cortex of the macaque.

Feeding-related gustatory, olfactory, and visual activation of the orbitofrontal cortex (OFC) decreases following satiety. Previous neurophysiological studies have concentrated on the caudolateral OFC (clOFC). We describe satiety-induced modulation of 23 gustatory, 5 water, and 15 control neurons in the medial OFC (mOFC), where gustatory neurons represent a much larger percentage of the population. For 15 of the 23 gustatory neurons (65%), every significant taste response evoked during pre-satiety testing decreased following satiety (X=70%). Responses evoked by the ineffective taste stimuli during pre-satiety testing were unchanged following satiety. The graded response decrements of the mOFC gustatory neurons stand in marked contrast to the clOFC responses, which are almost completely suppressed by satiety. Two other novel findings are reported here. First, all significant pre-satiety taste responses of four gustatory neurons increased following satiety (X=51%). Second, post-satiety emergent taste responses were observed in 7 of 15 neurons (47%) classified as non-responsive during pre-satiety testing. The presence of increased responsiveness and emergent gustatory neurons in the mOFC suggests that meal termination may require active processes as well as the passive loss of hedonic value. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relation of successful dietary restriction to change in bulimic symptoms: A prospective study of adolescent girls.

Recent experimental evidence that dietary restriction results in decreased bulimic and depressive symptoms seems inconsistent with findings from prospective studies and etiologic theory. However, because the dieting manipulated in these experiments may be unrepresentative of real-world weight loss dieting, the authors tested whether successful dietary restriction was associated with decreases in these outcomes by using longitudinal data from a school-based study of 496 adolescent girls. Moderately overweight participants who evidenced successful dietary restriction showed significantly greater decreases in bulimic symptoms than weight-matched participants who did not show successful dietary restriction; however, there were no effects for depressive symptoms. In conjunction with past experimental findings, results seem to imply that successful dietary restriction curbs bulimic symptoms, suggesting that current etiologic models may need revision. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical health problems, depressive mood, and cortisol secretion in old age: Buffer effects of health engagement control strategies.

Objective: This study examined the protective role played by control behaviors aimed at overcoming physical health problems (health engagement control strategies; HECS) in the associations between older adults' physical health problems, depressive mood, and diurnal cortisol secretion. It was expected that adaptive levels of HECS would buffer the adverse effects of physical health problems on depressive mood and diurnal cortisol secretion. Design and Measures: Physical health problems and HECS were measured in a cross-sectional sample of 215 community-dwelling older adults. In addition, participants' depressive mood and patterns of diurnal cortisol secretion were assessed across 3 days. Results: The findings demonstrate that physical health problems predicted high levels of depressive mood and diurnal cortisol secretion, but only among older adults who reported low levels of HECS (and not among older adults who reported high levels of HECS). Moreover, depressive mood completely mediated the buffering effect of HECS on the association between physical health problems and cortisol secretion. Conclusion: The results suggest that adaptive levels of HECS represent a psychological mechanism that can protect older adults from experiencing the adverse emotional and biological consequences of physical health problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Sheese et al. (2004).

Reports an error in the original article by B. Sheese et al (Health Psychology, 2004[Sep], Vol 23 [5], 457-464). On page 459, Table 1 contained errors in the reported values. The corrected table is provided. (The following abstract of this article originally appeared in record 2004-18051-003.) Research has shown that writing about emotional topics can positively influence physical and mental health. The current study tested the efficacy of an e-mail-based writing treatment and shows how such an implementation can aid in the search for moderators. Participants (N = 546) were randomly assigned to either a long- or short-interval traumatic writing condition or to a nonemotional writing control condition. In contrast to previous disclosure research, participants received and submitted their writing responses via e-mail. Health outcomes were assessed weekly for 5 weeks after treatment and were reported at the conclusion of the study. Results supported the effectiveness of an e-mail-based writing treatment in producing positive health outcomes and successfully identified several moderators of the writing treatment effect. The moderators implicated varied depending on the nature of the health outcome assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cultural transmission: Influence of contextual factors in asian indian immigrant parents' experiences.

Sixteen 1st-generation Asian Indian mothers and fathers were interviewed about the influence of immigration on retention of their own ethnic identity and their ability to promote a sense of ethnic identity in their 2nd-generation children. Data were analyzed with the consensual qualitative research methodology (C. E. Hill et al., 2005) and revealed ethnic identity retention to be influenced by engagement in cultural celebrations and activities, a need to hold onto tradition and upbringing, family ties, social support, and a rejection of perceived Western values. Ethnic identity retention was challenged by environmental obstacles and barriers within American society, loss of familial support, lack of cultural continuity, and an inability to have the "best of both worlds." Furthermore, participants identified specific values and strategies relevant to transmitting an ethnic identity to their children as well as specific challenges to this process, including limited familial and communal guidance and modeling, obstacles from Western culture, an inability to apply their own experience or upbringing, a lack of cultural knowledge, and the potential for intermarriage. Implications of the findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In situ wear studies of surface micromachined interfaces subject to controlled loading

Friction and wear are major limiting factors for the development and commercial implementation of devices fabricated by surface micromachining techniques. These tribological properties are studied using a polycrystalline silicon nanotractor device, which provides abundant, quantitative information about friction and wear at an actual microelectromechanical system (MEMS) interface. This in situ approach to measuring tribological properties of MEMS, combined with high-resolution atomic force microscope (AFM) images of wear tracks, provides insight into the effects of different MEMS surface processing on wear. In particular, monolayer coatings have a significant positive effect, while surface texturing does not strongly affect performance.     

Amygdala Central Nucleus Function Is Necessary for Learning, but Not Expression, of Conditioned Auditory Orienting.

In Pavlovian appetitive conditioning, rats often acquire 2 classes of conditioned responses: those whose form is determined by the reinforcer, and those whose form is determined by characteristics of the conditioned stimulus (CS). Consistent with the results of previous lesion studies, reversible inactivation of amygdala central nucleus function during pairings of an auditory CS with food prevented the acquisition of conditioned orienting responses specific to auditory CSs, whereas food-related conditioned behaviors were acquired normally. Neither inactivation nor posttraining neurotoxic lesions of the central nucleus affected the expression of previously acquired conditioned orienting. Thus, although the central nucleus is critical to the acquisition of information required for conditioned orienting to auditory cues, it is not needed for maintaining this information for later use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syntheses and Structures of Octamethylmetallocenes of Osmium

The reaction of sodium hexachloroosmate(IV) hydrate with five equivalents of tetramethylcyclopentadiene (C₅Me₄H₂) in refluxing ethanol yielded the novel coordination compound bis(tetramethylcyclopentadienyl)chloroosmocinium(IV) hexachloroosmate, [(η ⁵-C₅Me₄H)₂OsCl]₂[OsCl₆] (1). Compound 1 has been characterized by NMR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The cationic complex of 1 [(η ⁵-C₅Me₄H)₂OsCl]⁺, adopts a bent geometry with a ring centroid-osmium-ring centroid angle of 146.2° and an eclipsed conformation of its two tetramethylcyclopentadienyl rings. The addition of zinc powder to sodium hexachloroosmate(IV) hydrate and five equivalents of tetramethylcyclopentadiene in refluxing ethanol produced the known compound, bis(tetramethylcyclopentadienyl)osmium, (η ⁵-C₅Me₄H)₂Os (2). The crystal structure of 2 has been determined and it reveals an eclipsed arrangement of the tetramethylcyclopentadienyl rings in the solid state. The average Os–C_ring bond length in octamethylosmocene 2 (2.187 Å) is in accordance with corresponding bond lengths in osmocene, (η ⁵-C₅H₅)₂Os (2.19 Å) and decamethylosmocene, (η ⁵-C₅Me₅)₂Os (2.18 Å).     

New Dielectric Elastomers with Variable Moduli

Dielectric elastomers have been widely investigated for muscle‐like soft actuators and capacitive sensors. Mechanical properties play a central role in the performances of the active material. Most elastomers have specific moduli pre‐determined by the polymers' molecular structures, which are not suitable for applications in changing working conditions as natural muscles are capable of. Here new dielectric elastomers are described exhibiting variable moduli controlled via thermal treatment. The elastomers contain furan‐maleimide Diels–Alder adduct moieties to administer the crosslinking densities of the elastomeric networks via reversible Diels–Alder/retro‐Diels–Alder cycloaddition reaction, resulting in changes in the elastomers' moduli. One of the synthesized elastomers has moduli that can be controlled between 0.17 and 0.52 MPa incrementally and reversibly. Capacitive strain sensors based on this elastomer can be operated in both rigid and soft modes to achieve variable sensing response up to 30% linear strain. Actuators were fabricated and operated in both high strain mode (35% actuation area strain at 65 MV m^?1) and high force output mode (0.55 MPa at 104 MV m^?1). The elastomers can exhibit a range of stress–strain outputs in similar fashion as muscle.     

Barrier properties of poly(vinyl alcohol) membranes containing carbon nanotubes or activated carbon

Carbon nanotube addition has been shown to improve the mechanical properties of some polymers. Because of their unique adsorptive properties, carbon nanotubes may also improve the barrier performance of polymers used in contaminant containment. This study compares the barrier performance of poly(vinyl alcohol) (PVA) membranes containing single-walled carbon nanotubes (SWCNTs) to that for PVA containing powdered activated carbon (PAC). Raw and surface-functionalized versions of each sorbent were tested for their abilities to adsorb 1,2,4-trichlorobenzene and Cu(2+), representing the important hydrophobic organic and heavy metal contaminant classes, as they diffused across the PVA. In both cases, PAC (for 1,2,4-trichlorobenzene) and functionalized PAC (for Cu(2+)) outperformed SWCNTs on a per mass basis by trapping more of the contaminants within the barrier membrane. Kinetics of sorption are important in evaluating barrier properties, and poor performance of SWCNT-containing membranes as 1,2,4-TCB barriers is attributed to kinetic limitations.