Examination of Interpenetrating Polymer Networks of Polyurea in Silicone Molds Arising during Vacuum Casting Processes

We present an in-depth investigation of the aging effects in silicone molds for vacuum casting processes. Their lifetime is limited to a few production cycles due to contamination with the diisocyanate component of polyurethane casting materials. Using thermogravimetric analysis measurements, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and helium-ion-microscopy the chemical and physical mechanisms of the aging process have been identified. It has been shown that a diffusion process of diisocyanate into the cavity surface leads to the formation of interpenetrating polymer networks of polyurea derivatives in silicone rubber. This has been proven by extracting and analyzing polyurea of low molecular weights from the silicone.     

Interpersonal psychotherapy for co-occurring depression and chronic pain.

Up to 37% of individuals experience chronic pain during their lifetimes. Approximately one fourth of primary care patients with chronic pain also meet criteria for major depression. Many of these individuals fail to receive psychotherapy or other treatment for their depression; moreover, when they do, physical pain is often not addressed directly. Women, socioeconomically disadvantaged individuals, African Americans, and Latinos all report higher rates of pain and depression compared with other groups. This article describes a version of interpersonal psychotherapy tailored for patients with comorbid depression and chronic pain, interpersonal psychotherapy for depression and pain (IPT-P). IPT-P potentially could be delivered to many patient populations in a range of clinical settings, but this article focuses on its delivery within primary care settings for socioeconomically disadvantaged women. Adaptations include a brief 8-session protocol that incorporates strategies for anticipating barriers to psychotherapy, accepting patients' conceptualization of their difficulties, encouraging patients to consider the impact of their pain on their roles and relationships, emphasizing self-care, incorporating pain management techniques, and flexible scheduling. In addition, IPT-P is designed as an adjunct to usual medical pain treatment, and seeks to engage non–treatment-seeking patients in psychotherapy by focusing on accessibility and relevance of the intervention to concerns common among patients with pain. Identifying patients with comorbid depression and chronic pain and offering IPT-P as a treatment option have the potential to improve clinical outcomes for individuals with depression and chronic pain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decoupled Roles for the Atypical,Bifurcated Binding Pocket of the ybfF Hydrolase

Serine hydrolases have diverse intracellular substrates, biological functions, and structural plasticity, and are thus important for biocatalyst design. Amongst serine hydrolases, the recently described ybfF enzyme family are promising novel biocatalysts with an unusual bifurcated substrate‐binding cleft and the ability to recognize commercially relevant substrates. We characterized in detail the substrate selectivity of a novel ybfF enzyme from Vibrio cholerae (Vc‐ybfF) by using a 21‐member library of fluorogenic ester substrates. We assigned the roles of the two substrate‐binding clefts in controlling the substrate selectivity and folded stability of Vc‐ybfF by comprehensive substitution analysis. The overall substrate preference of Vc‐ybfF was for short polar chains, but it retained significant activity with a range of cyclic and extended esters. This broad substrate specificity combined with the substitutional analysis demonstrates that the larger binding cleft controls the substrate specificity of Vc‐ybfF. Key selectivity residues (Tyr116, Arg120, Tyr209) are also located at the larger binding pocket and control the substrate specificity profile. In the structure of ybfF the narrower binding cleft contains water molecules prepositioned for hydrolysis, but based on substitution this cleft showed only minimal contribution to catalysis. Instead, the residues surrounding the narrow binding cleft and at the entrance to the binding pocket contributed significantly to the folded stability of Vc‐ybfF. The relative contributions of each cleft of the binding pocket to the catalytic activity and folded stability of Vc‐ybfF provide a valuable map for designing future biocatalysts based on the ybfF scaffold.     

Independent components of magnetoencephalography: localization

We applied second-order blind identification (SOBI), an independent component analysis method, to MEG data collected during cognitive tasks. We explored SOBI's ability to help isolate underlying neuronal sources with relatively poor signal-to-noise ratios, allowing their identification and localization. We compare localization of the SOBI-separated components to localization from unprocessed sensor signals, using an equivalent current dipole modeling method. For visual and somatosensory modalities, SOBI preprocessing resulted in components that can be localized to physiologically and anatomically meaningful locations. Furthermore, this preprocessing allowed the detection of neuronal source activations that were otherwise undetectable. This increased probability of neuronal source detection and localization can be particularly beneficial for MEG studies of higher-level cognitive functions, which often have greater signal variability and degraded signal-to-noise ratios than sensory activation tasks.     

Effects of alcohol versus expectancy for alcohol on the incidence of graffiti following an experimental task.

Experimentally manipulated the conditions of beverage content and expectancy for alcohol in 29 heavy social-drinking (as determined by the Drinking Practices Questionnaire) male undergraduates. After completing a pencil-and-paper task, Ss found themselves in a situation where graffiti could apparently be written in and around the immediate surroundings with impunity. Regardless of expectations, Ss who actually drank alcohol were significantly more likely to write graffiti in this situation than were Ss who did not drink alcohol. This finding supports the importance of alcohol rather than expectancy as a causal influence on this form of disinhibited behavior. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extracellular recordings from patterned neuronal networks using planar microelectrode arrays

Neuronal cell networks have been reconstructed on planar microelectrode arrays (MEAs) from dissociated hippocampal pyramidal neurons. Microcontact printing (microCP) and a photoresist-liftoff method were used to selectively localize poly-L-lysine (PLL) on the surface of MEAs. Haptotaxis led to the organization of the neurons into networks localized adjacent to microelectrodes. Various grids of PLL with 2-25-microm-wide lines spaced by 50-200 microm with 15-25-microm nodes at intersection points were used to guide cell body attachment and neurite outgrowth. Bursting activity with spike amplitude attenuation was observed, and multichannel recordings detected instances of coincident firing activity. Finally, we present here an extracellular recording from a approximately 2 microm bundle of guided neurites.     

Short-term exposures to chronically toxic copper concentrations induce HSP70 proteins in midge larvae (Chironomus tentans)

In the present study, we investigated the induction of HSP70 proteins in Chironomus tentans in response to copper exposure. Larvae were exposed for 24 h to 0, 0.25, 0.5, 1.0 and 2.0 mgl(-1) copper, concentrations that were previously shown to cause growth reduction or mortality in 10 d bioassays. The induction of HSP70 was evaluated by Western blotting, and we observed a significant increase in HSP70 proteins over controls at all tested concentrations. The results suggest that short-term laboratory exposures to chronically toxic but acutely sublethal copper concentrations induce HSP70 proteins in C. tentans larvae.     

Action planning in the presence of distracting stimuli: An investigation into the time course of distractor effects.

Humans have a remarkable capability to respond efficiently to a stimulus of interest despite other stimuli competing for neural resources. The current study investigated how the human system copes with distracting stimuli. During each trial, participants viewed 2 sequential stimuli that were each associated with a specific action based on an arbitrary mapping. The 1st stimulus served as a distractor, and the 2nd stimulus required a response (target). When the distractor preceded the target by more than a few hundred milliseconds, response latencies were slower when the 2 stimuli were associated with the same response. The authors propose that this negative compatibility effect stemmed from an inhibitory mechanism that the human system utilizes to prevent the distractor from eliciting an unwanted response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)