Profiling the near field of a plasmonic nanoparticle with Raman-based molecular rulers

The enhanced local optical fields at the surface of illuminated metallic nanoparticles and nanostructures are of intense fundamental and technological interest. Here we report a self-consistent measurement of the spatial extent of the fringing field above a plasmonic nanoparticle surface. Bifunctional DNA-based adsorbate molecules are used as nanoscale optical rulers, providing two distinct surface enhanced Raman scattering signals that vary independently in intensity as a function of distance from the nanoparticle surface. While the measurement technique is calibrated on gold nanoshell surfaces with controlled and predictable electromagnetic nanoenvironments, this approach is broadly adaptable to a wide range of plasmonic geometries.     

Rollover crashes: predicting serious injury based on occupant, vehicle, and crash characteristics

The purpose of this research was to determine occupant, vehicle, and crash characteristics predicting serious injury during rollover crashes. We compared 27 case occupants with serious or greater severity injuries with 606 control occupants without injury or with only minor or moderate injury. Odds ratios (OR) for individual variables and logistic regression were used to identify predictive variables for serious injury associated with rollovers. Cases more often had thorax, spine, or head injury compared to controls that more often had extremity injuries. Intrusion (especially roof rail or B-pillar intrusion) at the occupant's position, the vehicle interior side and roof as sources of injury, and improper safety belt use were significantly associated with serious injury. Even when safety belt use or proper use was controlled for, occupants with greater magnitude of intrusion at their seat position were about 10 times more likely to receive serious injury. Although prevention of rollover crashes is the ultimate goal, it is important to develop safer vehicles and safety systems to better protect occupants who are involved in rollover crashes. This also requires improvement in data collection systems documenting these types of crashes.     

Remote Raman spectroscopy for planetary exploration: a review

In this review, we discuss the current state of standoff Raman spectroscopy as it applies to remote planetary applications, including standoff instrumentation, the technique's ability to identify biologically and geologically important analytes, and the feasibility to make standoff Raman measurements under various planetary conditions. This is not intended to be an exhaustive review of standoff Raman and many excellent papers are not mentioned. Rather it is intended to give the reader a quick review of the types of standoff Raman systems that are being developed and that might be suitable for astrospectroscopy, a look at specific analytes that are of interest for planetary applications, planetary measurement opportunities and challenges that need to be solved, and a brief discussion of the feasibility of making surface and plume planetary Raman measurements from an orbiting spacecraft.     

Disclosure of emotional events in groups at risk for posttraumatic stress disorder.

The disclosure of emotional events to various social intimates (disclosure targets) was measured in 2 samples (soldiers and first responders) at risk for posttraumatic stress disorder (PTSD), as well as a comparison sample of college students. These 3 groups completed survey measures of disclosure, and at risk groups also completed measures of PTSD symptoms and social support. Groups at risk for PTSD were less likely to disclose emotions related to potentially traumatic events than were college students reporting general emotional disclosure. Overall, disclosure of positive emotions was more likely than disclosure of negative emotions. Furthermore, amount of disclosure depended on the person to whom the individual disclosed. Within groups at risk for PTSD, social support was associated with lower levels of PTSD. However, this relationship was mediated by emotional disclosure to each target. Disclosure of positive emotions generally was associated with lower levels of PTSD, and disclosure of negative emotions to those with similar at-risk status was associated with greater levels of PTSD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Faith and unfaithfulness: Can praying for your partner reduce infidelity?

[Correction Notice: An erratum for this article was reported in Vol 99(4) of Journal of Personality and Social Psychology (see record 2010-20570-001). The article contained an error in Table 2, in the third column table heading. The correct table heading is provided in the erratum.] Because religion and/or spirituality is integral to the lives of a majority of the world population, we conducted 3 studies on the role of prayer in romantic relationships. Study 1 (N = 375) showed that prayer for the partner predicted lower levels of extradyadic romantic behavior over a 6-week period, over and beyond relationship satisfaction, and initial levels of extradyadic romantic behavior. In Study 2 (N = 83), we used an experimental design to show that participants assigned to pray for each day for 4 weeks engaged in lower levels of extradyadic romantic behavior during that time, compared with those who engaged in daily positive thoughts about the partner or a neutral activity. Perception of the relationship as sacred mediated the relation between experimentally manipulated prayer and later infidelity. Study 3 (N = 23) showed that objective observers rated participants who had been praying for their partner for 4 weeks as more committed to their romantic relationship than control participants. The implications of these results are then discussed. Because religion and/or spirituality is integral to the lives of a majority of the world population, we conducted 3 studies on the role of prayer in romantic relationships. Study 1 (N = 375) showed that prayer for the partner predicted lower levels of extradyadic romantic behavior over a 6-week period, over and beyond relationship satisfaction, and initial levels of extradyadic romantic behavior. In Study 2 (N = 83), we used an experimental design to show that participants assigned to pray for each day for 4 weeks engaged in lower levels of extradyadic romantic behavior during that time, compared with those who engaged in daily positive thoughts about the partner or a neutral activity. Perception of the relationship as sacred mediated the relation between experimentally manipulated prayer and later infidelity. Study 3 (N = 23) showed that objective observers rated participants who had been praying for their partner for 4 weeks as more committed to their romantic relationship than control participants. The implications of these results are then discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maternal separation alters social odor preference development in infant mice (Mus musculus).

This study examined whether daily periods of maternal separation during the first two weeks of life would decrease attraction to familiar nest odors in CD-1 mice 10 and 14 days old. We also investigated whether placing a group of mice (Mus musculus) in nest shavings during the 180-min separation period would mitigate possible separation-induced deficits. The maternal separation procedure has been widely used as a rodent model for the effects of inconsistent or inadequate early caretaking on human development. From postnatal day (PND) 1 to 14, litters were separated from the dam, but not littermates for either 15 or 180 min, or were facility-reared controls. Control, facility-reared mice preferred home-cage nest to clean familiar shaving odors on PND 10, but not PND 14. In contrast, home-cage nest odors attracted maternally separated mice on both test days. Our results suggest that maternal separation maintains the olfactory tether to the nest in a period when the attraction normally begins to weaken. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tobacco use moderates the association between major depression and obesity.

Objective: Based on a maladaptive coping explanation, the relationship between major depression (MD) and obesity could be strong among nonsmokers, who may engage in unhealthy eating and sedentary behavior to cope with depression. By contrast, the MD-obesity association could be weak among smokers, who can use tobacco (instead of food or sedentary behavior) to cope with mood symptoms. This study examined smoking status and tobacco dependence as moderators of the MD-obesity link. Design: Correlational, cross-sectional population-based survey of 41,654 U.S. adults. Main Outcome Measures: Obesity (body mass index [BMI] ≥30 kg/m2) and quantitative BMI value. Results: Current smoking status moderated the association between past-year MD and current obesity, as well as the link between MD and BMI value (ps ≤ .0001). MD predicted obesity and BMI among nonsmokers (ps ps ≥ .10). Similar findings emerged with tobacco dependence as the moderator. Each finding persisted after accounting for demographics, psychiatric variables, and potential confounds. Conclusion: Tobacco use characteristics appear to moderate the MD-obesity association in the U.S. population. These findings may shed light on the mechanisms linking MD and obesity and have implications for identifying which individuals may benefit most from obesity interventions that target depressive symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The velocity of plate precipitates growing by the ledge mechanism

Experiments have shown that plate-shaped precipitates in alloys most often grow by a ledge mechanism where mobile steps at the particle–matrix interface propagate at constant velocity in the growth direction and the steps are separated by immobile terraces. In this work the concentration field in the matrix phase during growth is formulated by a boundary integral technique, which correctly accounts for the step-terrace structure. By examining the behavior at the precipitate tip and using a stability criterion to determine the plate thickness, a relationship is established between the growth velocity, the radius of curvature of the plate tip and the supersaturation. When compared with previous theoretical treatments based on the Horvay–Cahn, Ivantsov, Trivedi solution, the boundary integral result is able to describe the velocities obtained in previous experiments on the Al–Ag system more accurately, and the improved agreement does not depend on the assumption of a finite kinetic attachment term. However, the new criterion is not able to reproduce data for Fe–C alloys. Possible reasons for the discrepancy are discussed.     

Niobium(V) oxide (Nb2O5): application to phosphoproteomics

Proteomics-based analysis of signaling cascades relies on a growing suite of affinity resins and methods aimed at efficient enrichment of phosphorylated peptides from complex biological mixtures. Given the heterogeneity of phosphopeptides and the overlap in chemical properties between phospho- and unmodified peptides, it is likely that the use of multiple resins will provide the best combination of specificity, yield, and coverage for large-scale proteomics studies. Recently titanium and zirconium dioxides have been used successfully for enrichment of phosphopeptides. Here we report the first demonstration that niobium pentoxide (Nb 2O 5) provides for efficient enrichment and recovery ( approximately 50-100%) of phosphopeptides from simple mixtures and facilitates identification of several hundred putative sites of phosphorylation from cell lysate. Comparison of phosphorylated peptides identified from Nb 2O 5 and TiO 2 with sequences in the PhosphoELM database suggests a useful degree of divergence in the selectivity of these metal oxide resins. Collectively our data indicate that Nb 2O 5 provides efficient enrichment for phosphopeptides and offers a complementary approach for large-scale phosphoproteomics studies.     

Influence of an Electric Field on the Burning Behavior of Solid Fuels and Propellants

An experimental study on the effects of an applied external electric field on the combustion behavior of solid fuels and solid propellants has been conducted. In an opposed flow burning configuration, application of an electric field was shown to extinguish a paraffin fuel and gaseous oxygen flame over a broad range of operating conditions. When subjected to the electric field, burning paraffin fuel strands were found to extinguish at various axial locations relative to the exit of the oxidizer gas jet. Extinguishment location was found to be a function of field strength as well as electrode surface area, while changes in polarity did not significantly alter the results. In addition, the combustion behaviors of two composite solid rocket propellants were studied while subjected to an external electric field. Both propellants were based on HTPB/AP combinations, with one propellant containing aluminum and the other being non‐aluminized. Application of an electric field to the composite solid rocket propellant strands demonstrated decreases in propellant burning rate under all operating conditions for both propellants including changes in polarity. The flame structure of the aluminized propellant was examined closely as the luminosity, flame length, and flame width varied significantly with field strength and burning location of the strand relative to the electrodes.