Design,Realization, and Characterization of Advanced Adhesives for Joining Ultra‐Stable C/C Based Components

The aim of this work is to develop high‐performance adhesives to join carbon fiber reinforced composites (C/C) for use in aerospace applications; in order to guarantee sound mechanical strength, a low coefficient of thermal expansion, and ease of application on large components. Several different adhesive formulations, based on phenolic or cyanate‐ester resins (charged with the maximum experimentally feasible amount of carbon‐based fillers), are developed and tested. The measurements of the lap shear strength at room temperature of the C/C joined by means of one phenolic and one cyanate ester‐based resin demonstrates that these formulations are the most suitable for the given application. A complete characterization, by means of viscosimetry, dilatometry, and thermal gravimetric analysis, coupled with gas analysis by means of mass spectroscopy, confirms that the phenolic‐based formulation is the most promising joining material. A nano‐indenter is used to obtain its Young modulus and hardness, both inside the joint and as a bulk cured adhesive.     

Salt Intake from Processed Meat Products: Benefits,Risks and Evolving Practices

Currently, there is major consumer concern about dietary salt intake worldwide. However, even with the development of contemporary preservation practices, sodium chloride is still essential in processed meat products. Despite a long history of use, salt is now seriously controversial in food due to health concerns that are mostly related to high blood pressure and cardiovascular risks. Changes in meat processing methods have reduced those potential risks, but different perceptions continue to shape how consumers and society view dietary salt. The current consumer demand for additive‐free food, such as the clean‐label movement, has renewed consumer willingness for naturalness in food products.     

Engineering Large Anisotropic Magnetoresistance in La0.7Sr0.3MnO3 Films at Room Temperature

The magnetoresistance (MR) effect is widely used in technologies that pervade the world, from magnetic reading heads to sensors. Diverse contributions to MR, such as anisotropic, giant, tunnel, colossal, and spin‐Hall, are revealed in materials depending on the specific system and measuring configuration. Half‐metallic manganites hold promise for spintronic applications but the complexity of competing interactions has not permitted the understanding and control of their magnetotransport properties to enable the realization of their technological potential. This study reports on the ability to induce a dominant switchable magnetoresistance in La_0.7Sr_0.3MnO₃ epitaxial films at room temperature (RT). By engineering an extrinsic magnetic anisotropy, a large enhancement of anisotropic magnetoresistance (AMR) is achieved which at RT leads to signal changes much larger than the other contributions such as the colossal magnetoresistance. The dominant extrinsic AMR exhibits large variation in the resistance in low field region, showing high sensitivity to applied low magnetic fields. These findings have a strong impact on the real applications of manganite‐based devices for the high‐resolution low field magnetic sensors or spintronics.     

Effect of filler level and particle size on dental caries-inhibiting Ca–PO4 composite

Secondary caries and restoration fracture are common problems in restorative dentistry. The aim of this study was to develop Ca–PO₄ nanocomposite having improved stress-bearing properties and Ca and PO₄ ion release to inhibit caries, and to determine the effects of filler level. Nanoparticles of dicalcium phosphate anhydrous (DCPA), two larger DCPA powders, and reinforcing whiskers were incorporated into a resin. A 6 × 3 design was tested with six filler mass fractions (0, 30, 50, 65, 70, and 75%) and three DCPA particle sizes (112 nm, 0.88 μm, 12.0 μm). The DCPA nanocomposite at 75% fillers had a flexural strength (mean ± SD; n = 6) of 114 ± 23 MPa, matching the 112 ± 22 MPa of a commercial non-releasing, hybrid composite (P > 0.1). This was 2-fold of the 60 ± 6 MPa of a commercial releasing control. Decreasing the particle size increased the ion release. Increasing the filler level increased the ion release at a rate faster than being linear. The amount of ion release from the nanocomposite matched or exceeded those of previous composites that released supersaturating levels of Ca and PO₄ and remineralized tooth lesions. This suggests that the much stronger nanocomposite may also be effective in remineralizing tooth lesion and inhibiting caries. In summary, combining calcium phosphate nanoparticles with reinforcing co-fillers in the composite provided a way to achieving both caries-inhibiting and stress-bearing capabilities. Filler level and particle size can be tailored to achieve optimal composite properties. Disclaimer: Certain commercial materials and equipment are identified to specify the experimental procedure. This does not imply recommendation or endorsement by NIST or ADAF.     

Affiliation with antisocial peers, susceptibility to peer influence, and antisocial behavior during the transition to adulthood.

Developmental theories suggest that affiliation with deviant peers and susceptibility to peer influence are important contributors to adolescent delinquency, but it is unclear how these variables impact antisocial behavior during the transition to adulthood, a period when most delinquent individuals decline in antisocial behavior. Using data from a longitudinal study of 1,354 antisocial youth, the present study examined how individual variation in exposure to deviant peers and resistance to peer influence affect antisocial behavior from middle adolescence into young adulthood (ages 14 to 22 years). Whereas we find evidence that antisocial individuals choose to affiliate with deviant peers, and that affiliating with deviant peers is associated with an individual’s own delinquency, these complementary processes of selection and socialization operate in different developmental periods. In middle adolescence, both selection and socialization serve to make peers similar in antisocial behavior, but from ages 16 to 20 years, only socialization appears to be important. After age 20, the impact of peers on antisocial behavior disappears as individuals become increasingly resistant to peer influence, suggesting that the process of desistance from antisocial behavior may be tied to normative changes in peer relations that occur as individuals mature socially and emotionally. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of divided attention on temporal processing in patients with lesions of the cerebellum or frontal lobe.

Prefrontal cortex and cerebellum have both been implicated in temporal processing tasks although the exact contribution of each system remains unclear. To investigate this issue, control participants and patients with either prefrontal or cerebellar lesions were tested on temporal and nontemporal perceptual tasks under 2 levels of attentional load. Each trial involved a comparison between a standard tone and a subsequent comparison tone that varied in frequency, duration, or both. When participants had to make concurrent judgments on both dimensions, patients with frontal lobe lesions were significantly impaired on both tasks whereas the variability of cerebellar patients increased in the duration task only. This dissociation suggests that deficits on temporal processing tasks observed in frontal patients can be related to the attention demands of such tasks; cerebellar patients have a more specific problem related to timing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contemporary research on parenting: The case for nature and nurture.

Current findings on parental influences provide more sophisticated and less deterministic explanations than did earlier theory and research on parenting. Contemporary research approaches include (a) behavior-genetic designs, augmented with direct measures of potential environmental influences; (b) studies distinguishing among children with different genetically influenced predispositions in terms of their responses to different environmental conditions; (c) experimental and quasi-experimental studies of change in children's behavior as a result of their exposure to parents' behavior, after controlling for children's initial characteristics; and (d) research on interactions between parenting and nonfamilial environmental influences and contexts, illustrating contemporary concern with influences beyond the parent–child dyad. These approaches indicate that parental influences on child development are neither as unambiguous as earlier researchers suggested nor as insubstantial as current critics claim. (PsycINFO Database Record (c) 2010 APA, all rights reserved)