Remotely Light‐Powered Soft Fluidic Actuators Based on Plasmonic‐Driven Phase Transitions in Elastic Constraint

Materials capable of actuation through remote stimuli are crucial for untethering soft robotic systems from hardware for powering and control. Fluidic actuation is one of the most applied and versatile actuation strategies in soft robotics. Here, the first macroscale soft fluidic actuator is derived that operates remotely powered and controlled by light through a plasmonically induced phase transition in an elastomeric constraint. A multiphase assembly of a liquid layer of concentrated gold nanoparticles in a silicone or styrene–ethylene–butylene–styrene elastic pocket forms the actuator. Upon laser excitation, the nanoparticles convert light of specific wavelength into heat and initiate a liquid‐to‐gas phase transition. The related pressure increase inflates the elastomers in response to laser wavelength, intensity, direction, and on–off pulses. During laser‐off periods, heating halts and condensation of the gas phase renders the actuation reversible. The versatile multiphase materials actuate—like soft “steam engines”—a variety of soft robotic structures (soft valve, pnue‐net structure, crawling robot, pump) and are capable of operating in different environments (air, water, biological tissue) in a single configuration. Tailored toward the near‐infrared window of biological tissue, the structures actuate also through animal tissue for potential medical soft robotic applications.     

Consolidation by spark plasma sintering (SPS) of polyetheretherketone

The present study deals with the consolidation of an ultra‐high performance polymer, the poly(ether ether ketone) (PEEK), for structural applications, using the powder metallurgy (PM) way, and more precisely the Spark Plasma Sintering (SPS) processing. The effects of SPS parameters such as temperature, pressure, and dwell time on density and mechanical properties of PEEK were investigated via a Design of Experiments (DoE). A temperature of 250 °C, a pressure of 40 MPa, and a dwell time of 20 min have been identified as the optimal SPS process parameters. In these conditions, a density of 1.31 g / cm³ was reached and homogeneous mechanical properties in the volume determined by means of compression tests were found with a compressive modulus of 2.75 GPa, a yield strength of 134 MPa, and a maximum compressive strain of 43%. These results are better than those of commercial products obtained by injection molding. The pressure appears to be a significant parameter on PEEK properties and plays positive or negative roles according to the responses of DoE studied. To our knowledge, it is one of the first studies based on the application of the PM techniques for PEEK consolidation showing the possibility to process below its melting point. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44911.     

Disinfection of circulating water systems by ultraviolet light and halogenation

Continuous ultraviolet light (u.v.) and chemical disinfection of circulating water systems were evaluated. Direct comparisons of the biocidal effectiveness of u.v. light vs halogenation were tested with Legionella spp and Pseudomonas aeruginosa because of their association with the acquisition of overt clinical disease from water-containing appliances. Findings indicated that six species of Legionella and P. aeruginosa were killed by a moderate level of u.v. radiation. L. pneumophila and other bacteria in a circulating water system were effectively killed by a biocidal u.v. light. However, free chlorine levels needed to kill Legionella, Pseudomonas, and Flavobacterium within 1 min were found to be greater than 4 mg ml^?1. Data from a long-term field trial with u.v. light treatment of evaporative condenser water showed a significant reduction in numbers of bacteria. Ultraviolet disinfection of hospital hydrotherapy whirlpools confirmed the utility of this mode of disinfection under circumstances where chlorination may not be practical for medical reasons. These findings were confirmed during investigations of halogenated or u.v.-treated public hot tub/whirlpools. The effectiveness of routine chemical disinfection for controlling microbial flora in a cooling tower was also evaluated. The 2 month survey indicated that the numbers of bacteria, including Legionella, were not affected by two biocides that were used. The observations made during this investigation support the conclusion that u.v. light disinfection of water-containing systems may be an appropriate alternative or supplement to chemical biocides.     

Effectiveness of peer-led eating disorders prevention: A replication trial.

The aim of this study was to replicate and extend results of a previous trial that investigated the effectiveness of 2 peer-led eating disorders prevention interventions in reducing eating disorder risk factors in undergraduate women (C. B. Becker, L. M. Smith, & A. C. Ciao, 2006). To extend findings from the previous study by allowing for investigation of differential response, the authors randomly assigned a larger sample of both higher and lower risk sorority members (N = 188; age M = 18.64 years, range = 18-21; 20% minority) to either a cognitive dissonance (CD) or a media advocacy (MA) intervention under naturalistic conditions. Interventions were delivered by trained sorority peer leaders and consisted of two 2-hr group sessions. Participants completed questionnaires that assessed eating disorder risk factors at pretreatment, posttreatment, 7-week follow-up, and 8-month follow-up. Results indicate that both interventions reduced thin-ideal internalization, body dissatisfaction, dietary restraint, and bulimic pathology at 8 months, although higher and lower risk participants responded somewhat differently. Both CD and MA generally appeared effective for higher risk participants; only CD, however, appeared to benefit lower risk participants. Results further support the viability of using peer leaders in dissonance-based prevention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The utility and comparative incremental validity of the MMPI-2 and Trauma symptom Inventory validity scales in the detection of feigned PTSD.

The authors examined the comparative predictive capacity of the Trauma Symptom Inventory (TSI) Atypical Response Scale (ATR) and the standard set of Minnesota Multiphasic Personality Inventory-2 (MMPI-2) fake-bad validity scales (i.e., F, FB, Fp, FBS) to detect feigned posttraumatic stress disorder (PTSD). Remitted trauma victims (n = 60) completed the TSI and MMPI-2 under standard (honest) instructions and then were randomly assigned to 1 of 2 experimental conditions (noncoached/validity scale coached) in which they were administered these instruments again with instruction to fake PTSD. These test protocols were compared with TSI and MMPI-2 results from workplace injury claimants with PTSD (n = 84). The ATR and FBS were able to distinguish only the noncoached participants instructed to fake from the PTSD claimants; in contrast, the F, FB, and Fp scales were able to distinguish both the noncoached and the validity-scale-coached participants from the PTSD claimants. F, FB, and Fp always outperformed the ATR and FBS; neither the ATR nor the FBS was able to add incremental predictive variance to that of F, FB, or Fp. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shotgun analysis of integral membrane proteins facilitated by elevated temperature

The beneficial effects on peak selectivity and resolution of conducting liquid chromatography (LC) at elevated temperature (e.g., 30-80 degrees C) are generally well-known; however, its importance for peptide recovery is not nearly as well recognized. This report demonstrates that microLC analysis of membrane proteomic samples significantly benefits from the application of heat. Enriched membrane and membrane-embedded peptides (the latter obtained by membrane shaving) were analyzed by microLC-tandem mass spectrometry (MS/MS) from 20 to 60 degrees C using a standard reversed-phase material. Maximal protein and hydrophobic peptide recovery was obtained at 60 degrees C. The membrane-shaving method employed, a recently optimized version of the high pH/proteinase K protocol, provided significant integral membrane protein enrichment: 98% of identified proteins were predicted to have at least one transmembrane domain (87% to have at least three), and 68% of peptides were predicted to contain transmembrane segments. Analysis of this highly enriched sample at elevated temperature increased protein identifications by 400%, and peptide identifications by 500%, as compared to room-temperature separation. Given that most microLC-MS/MS analyses are currently conducted at room temperature, the findings described herein should be of considerable value for improving the comprehensive study of integral membrane proteins.     

Chloroplastic glycolipids fuel aldehyde biosynthesis in the marine diatom Thalassiosira rotula

Enzymatic preparations and specialized analytical tools have shown that chloroplast-derived glycolipids are the main substrates for the biosynthetic pathway that produces antiproliferative polyunsaturated aldehydes in broken cells of the marine diatom Thalassiosira rotula. This process, which is associated with the formation of free fatty acids and lyso compounds from polar lipids but not triglycerides, is largely dependent on glycolipid hydrolytic activity, rather than phospholipase A(2) as previously suggested. Preliminary characterization of lipolytic enzymes has revealed protein bands of 40-45 kDa. Under native conditions these proteins seem to be associated with soluble aggregates that have an apparent molecular weight of approximately 200 kDa. The biochemical process, which is similar to that described in the algal-bloom forming diatom Skeletonema costatum, suggests a mechanism based on decompartmentalization and mixing of preexisting enzymes and substrates.