Neuroendocrine regulation and physical and relational aggression: The moderating roles of child maltreatment and gender.

The purpose of the present investigation was to examine the association between circadian rhythms of cortisol and physical and relational aggression. Morning arrival, prelunch, and afternoon predeparture salivary cortisol were assessed among 418 maltreated and nonmaltreated children (52% maltreated; 49% female) attending a summer day camp. Counselors and peers rated participants' involvement in physically and relationally aggressive behaviors. Results indicated that physical aggression was associated with heightened cortisol following morning arrival and relatively steep declines in cortisol over the day, whereas relational aggression was associated with low cortisol following morning arrival and blunted diurnal change in cortisol. Moreover, maltreatment was a significant moderator of this relationship such that aggression was related to greater cortisol dysregulation among nonmaltreated than among maltreated children. The findings suggest that physiological correlates of aggression may differ for physical and relational forms of aggression and among maltreated versus nonmaltreated populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhanced Fibrinolysis with Magnetically Powered Colloidal Microwheels

Thrombi that occlude blood vessels can be resolved with fibrinolytic agents that degrade fibrin, the polymer that forms between and around platelets to provide mechanical stability. Fibrinolysis rates however are often constrained by transport‐limited delivery to and penetration of fibrinolytics into the thrombus. Here, these limitations are overcome with colloidal microwheel (µwheel) assemblies functionalized with the fibrinolytic tissue‐type plasminogen activator (tPA) that assemble, rotate, translate, and eventually disassemble via applied magnetic fields. These microwheels lead to rapid fibrinolysis by delivering a high local concentration of tPA to induce surface lysis and, by taking advantage of corkscrew motion, mechanically penetrating into fibrin gels and platelet‐rich thrombi to initiate bulk degradation. Fibrinolysis of plasma‐derived fibrin gels by tPA‐microwheels is fivefold faster than with 1 µg mL^?1 tPA. µWheels following corkscrew trajectories can also penetrate through 100 µm sized platelet‐rich thrombi formed in a microfluidic model of hemostasis in ≈5 min. This unique combination of surface and bulk dissolution mechanisms with mechanical action yields a targeted fibrinolysis strategy that could be significantly faster than approaches relying on diffusion alone, making it well‐suited for occlusions in small or penetrating vessels not accessible to catheter‐based removal.     

Inhibitors for prolonging corrosion protection of Mg-rich primer on Al alloy 2024-T3

This research investigated the possibility of adding inhibitors into magnesium-rich primer (MgRP) to prolong the corrosion protection time of MgRP on Al alloy 2024-T3. Three inhibitors: sodium benzoate (SB), sodium dodecylbenzenesulfonate (SDBS), and 8-hydroxyquinoline (HQ), were tested and added into MgRPs separately. Potentiodynamic scans on pellet electrodes confirmed that the inhibitors reduced Mg corrosion rate. The coating systems with and without inhibitors were compared through electrochemical tests, hydrogen volume measurement, accelerated weathering tests, and adhesion tests. It was observed that the addition of SB, SDBS, and HQ into MgRPs could prolong cathodic protection time and improved barrier properties of MgRPs, without compromising adhesion strength.     

Effects of maternal negativity and of early and recent recurrent depressive disorder on children's false belief understanding.

Research has shown that children of depressed mothers are at risk for problems in a variety of developmental domains; however, little is known about the effects of maternal depression on children's emerging understanding of false beliefs. In this study, 3 false belief tasks were administered to 5-year-old children whose mothers had either met criteria for major depressive disorder within the first 20 months of the child's life (n = 91) or had never been depressed (n = 50). Significant difficulties in performance were found among the children of depressed mothers, especially those whose mothers had experienced early and recent recurrent depressive disorder. Regardless of diagnostic status, children whose mothers exhibited negativity during problem-solving tasks administered at an earlier developmental period also were less likely to demonstrate false belief understanding. These effects remained even after child verbal ability was controlled. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanistic details of acid-catalyzed reactions and their role in the selective synthesis of triptane and isobutane from dimethyl ether

We report here kinetic and isotopic evidence for the elementary steps involved in dimethyl ether (DME) homologation and for their role in the preferential synthesis of 2,2,3-trimethylbutane (triptane) and isobutane. Rates of methylation of alkenes and of hydrogen transfer, isomerization and β-scission reactions of the corresponding alkoxides formed along the homologation path to triptane were measured using mixtures of ¹³C-labeled dimethyl ether (¹³C-DME) and unlabeled alkenes on H-BEA. DME-derived C₁ species react with these alkenes to form linear butyls from propene, isopentyls from n-butenes, 2,3-dimethylbutyls from isopentenes, and triptyls from 2,3-dimethylbutenes; these kinetic preferences reflect the selective formation of the more highly substituted carbenium ions and the retention of a four-carbon backbone along the path to triptane. Hydrogen transfer reactions terminate chains as alkanes; chain termination probabilities are low for species along the preferred methylation path, but reach a maximum at triptyl species, because tertiary carbenium ions involved in hydrogen transfer are much more stable than those with primary character required for triptene methylation. Alkenes and alkanes act as hydrogen donors and form unsaturated species as precursors to hexamethylbenzene, which forms to provide the hydrogen required for the DME-to-alkanes stoichiometry. Weak allylic C–H bonds in isoalkenes are particularly effective hydrogen donors, as shown by the higher termination probabilities and ¹²C content in hexamethylbenzene as ¹²C-2-methyl-2-butene and ¹²C-2,3-dimethyl-2-butene pressures increased in mixtures with ¹³C-DME. The resulting dienes and trienes can then undergo Diels–Alder cyclizations to form arenes as stable by-products. Isomerization and β-scission reactions of the alkoxides preferentially formed in methylation of alkenes are much slower than hydrogen transfer or methylation rates, thus preventing molecular disruptions along the path to triptane. Methylation at less preferred positions leads to species with lower termination probabilities, which tend to grow to C₈₊ molecules; these larger alkoxides undergo facile β-scission to form tert-butoxides that desorb preferentially as isobutane via hydrogen transfer; such pathways resolve methylation “missteps” by recycling the carbon atoms in such chains to the early stages of the homologation chain and account for the prevalence of isobutane among DME homologation products. These findings were motivated by an inquiry into the products formed via C₁ homologation, but they provide rigorous insights about how the structure and stability of carbenium ions specifically influence the rates of methylation, hydrogen transfer, β-scission, and isomerization reactions catalyzed by solid acids.     

Influence of Roasting on the Water Sorption Isotherms of Argentinean Algarroba (Prosopis alba Griseb) Pods

Prosopis alba is an arboreal legume that occurs naturally in Argentine. Its fruits (algarroba or Prosopis pods) are dried or roasted, ground and then used in foods and feeds. The influence of roasting process on the water sorption isotherms of Prosopis pod flour at three storage temperatures was studied. The equilibrium data for each sorption isotherm were determined by the standard static gravimetric method. Experimental values were fitted to the BET and GAB sorption models. Type II isotherms were obtained according to Brunauer classification. The calculated isosteric heats of sorption (Qs) near the monolayer moisture content were 7.30 and 7.68 kJ/mol for raw and roasted flour, respectively. The results showed that roasting did not significantly change the behavior of the products with regard to water adsorption, although a slight reduction of the tendency to humectation was observed, this being somewhat less spontaneous. In this aspect, the stability of Prosopis flour is similar in the raw and roasted states.     

Hydrogen Spillover in Ga2O3–Pd/SiO2 Catalysts for Methanol Synthesis from CO2/H2

The hydrogenation of CO₂ was investigated on Ga₂O₃-promoted Pd/SiO₂ catalyts and mechanical mixtures of Ga₂O₃/SiO₂ and Pd/SiO₂ catalysts (H₂/CO₂ = 3; P = 3.0 MPa; T = 523 K). By means of the latter it was possible to demonstrate that atomic hydrogen, H_s, can be generated by Pd⁰ far from Ga₂O₃, and move (spill-over) there to reach the other reactive species (formates) and complete the reaction cycle. The reaction results indicate that (as also evidenced by in situ FTIR) the Ga₂O₃-Pd/SiO₂ catalyst works as a true bi-functional system. The metal-promoter intimacy is not decisive in terms of the catalytic chemistry of the system, but the closeness between the Pd crystallites and the Ga₂O₃ surface patches boost the activity, owing to a minimized effort in the H_s supply to the latter.     

Affective, organizational, and relational characteristics of maltreating families: A system's perspective.

In-home structured interactions of 42 maltreating families (neglect: n?=?12; physical abuse: n?=?19; sexual abuse: n?=?11) and 23 low-income comparison families with preschool-aged children were examined to determine whether maltreating and nonmaltreating families could be distinguished by system-level processes. Coding from videotapes of family interactions yielded ratings for affective, organizational, and relational features of each family unit. Results from family coding demonstrated that sexually abusive families had significantly more difficulties regulating anger, evidenced more chaos and less role clarity, and relied less on adaptive-flexible relationship strategies than nonmaltreating families. The importance of family climate and structure, above and beyond individual maltreatment acts, are highlighted. Treatment and social policy implications and directions for future research in the family study of child maltreatment are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)