Exercise increases hippocampal neurogenesis to high levels but does not improve spatial learning in mice bred for increased voluntary wheel running.

The hippocampus is important for the acquisition of new memories. It is also one of the few regions in the adult mammalian brain that can generate new nerve cells. The authors tested the hypothesis that voluntary exercise increases neurogenesis and enhances spatial learning in mice selectively bred for high levels of wheel running (S mice). Female S mice and outbred control (C) mice were housed with and without running wheels for 40 days. 5-Bromodeoxyuridine was used to label dividing cells. The Morris water maze was used to measure spatial learning. C runners showed a strong positive correlation between running distance and new cell number, as well as improved learning. In S runners, neurogenesis increased to high levels that reached a plateau, but no improvement in learning occurred. This is the first evidence that neurogenesis can occur without learning enhancement. The authors propose an alternative function of neurogenesis in the control of motor behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlating Perceived Crispness Intensity to Physical Changes in an Amorphous Snack Food

A crispy amorphous food was equilibrated to different moisture contents. These samples were tested for the glass transition temperature (T_g) using mechanical methods. The brittle-ductile transition temperature (T_b) was determined using force-deformation methods. Finally, the temperature where the onset to the sharp decrease in crispness intensity occurred (T_ci) was determined by a 10-member sensory panel rating the crispness intensity. The relationships of the T_g, the T_b, and the T_ci were determined using three different statistical methods. The results of this research indicated that the T_g, the T_b, and the T_ci were related to one another as a function of moisture content.     

Parent-child interactions, peripheral serotonin, and self-inflicted injury in adolescents.

Self-inflicted injury in adolescence indicates significant emotional and psychological suffering. Although data on the etiology of self-injury are limited, current theories suggest that the emotional lability observed among self-injuring adolescents results from complex interactions between individual biological vulnerabilities and environmental risk. For example, deficiencies in serotonergic functioning, in conjunction with certain family interaction patterns, may contribute to the development of emotional lability and risk for self-injury. The authors explored the relation between peripheral serotonin levels and mother-child interaction patterns among typical (n = 21) and self-injuring (n = 20) adolescents. Findings revealed higher levels of negative affect and lower levels of both positive affect and cohesiveness among families of self-injuring participants. Peripheral serotonin was also correlated with the expression of positive affect within dyads. Furthermore, adolescents' serotonin levels interacted with negativity and conflict within dyads to explain 64% of the variance in self-injury. These findings underscore the importance of considering both biological and environmental risk factors in understanding and treating self-injuring adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychotherapy unification.

A unifying paradigm is proposed to integrate the deeper relationships that exist among seemingly dissimilar approaches to psychotherapy. Unification derives from anchoring human functioning to personality processes and the universal principles of evolution. Parallels are drawn from medical science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermochemical Modeling of Oxide Glasses

A modified associate species approach is used to model the liquid phase in oxide systems. The relatively simple technique treats oxide liquids as solutions of end-member and associate species. The model is extended to representing glasses by treating them as undercooled liquids. Equilibrium calculations using the model allow the determination of species activities, phase separation, precipitation of crystalline phases, and volatilization. In support of nuclear waste glass development, a model of the Na₂O–Al₂O₃–B₂O₃–SiO₂ system has been developed that accurately reproduces its phase equilibria. The technique has been applied to the CaO–SiO₂ system, which is used to demonstrate how two immiscible liquids can be treated.     

Germanium-on-insulator substrates by wafer bonding

Single-crystal Ge-on-insulator (GOI) substrates, made by bonding a hydrogen-implanted Ge substrate to a thermally oxidized, silicon handle wafer, are studied for properties relevant to device fabrication. The stages of the layer transfer process are examined through transmission electron microscopy (TEM) from the initial hydrogen implant through the final Ge film polish. The completed GOI substrate is characterized for film uniformity, surface quality, contamination, stress, defectivity, and thermal robustness using a variety of techniques and found to be acceptable for initial device processing.     

Ultrafast Near‐Infrared Light‐Triggered Intracellular Uncaging to Probe Cell Signaling

The possibility of regulating cell signaling with high spatial and temporal resolution within individual cells and complex cellular networks has important implications in biomedicine. This article demonstrates a general strategy that uses near‐infrared tissue‐penetrating laser pulses to uncage biomolecules from plasmonic gold‐coated liposomes, i.e., plasmonic liposomes, to activate cell signaling in a nonthermal, ultrafast, and highly controllable fashion. Near‐infrared picosecond laser pulse induces transient nanobubbles around plasmonic liposomes. The mechanical force generated from the collapse of nanobubbles rapidly ejects encapsulated compound within 0.1 ms. This article shows that single pulse irradiation triggers the rapid intracellular uncaging of calcein from plasmonic liposomes inside endolysosomes. The uncaged calcein then evenly distributes over the entire cytosol and nucleus. Furthermore, this article demonstrates the ability to trigger calcium signaling in both an immortalized cell line and primary dorsal root ganglion neurons by intracellular uncaging of inositol triphosphate (IP₃), an endogenous cell calcium signaling second messenger. Compared with other uncaging techniques, this ultrafast near‐infrared light‐driven molecular uncaging method is easily adaptable to deliver a wide range of bioactive molecules with an ultrafast optical switch, enabling new possibilities to investigate signaling pathways within individual cells and cellular networks.     

Sensing polarization with variable coherence tomography

Variable coherence tomography (VCT) was recently developed by Baleine and Dogariu for the purpose of directly sensing the second-order statistical properties of a randomly scattering volume [J. Opt. Soc. Am. A21, 1917 (2004)]. In this paper we generalize the theory of VCT to include polarized inputs and anisotropic scatterers. In general the measurement of the scattered coherency matrix or Stokes vector is not adequate to describe the scattering, as these quantities depend on the coherence state of the incident beam. However, by controlling the polarized coherence properties of the source beam, VCT can be generalized to probe the polarimetric scattering properties of objects from a single-point Stokes vector or coherency matrix measurements. With polarized VCT, we are able to design a method that can measure analogous information to the polarimetric bidirectional reflection distribution function (BRDF), but do it from monostatic data. This capability would allow the BRDF to be measured remotely without having to adjust either the incident or observation angle with respect to the target.