Synthesis and characterisation of fluorescent pyrene‐end‐capped polylactide fibres

Fluorescent markers are critical for tracking the position and movement of molecules both in vivo and in vitro. Conventionally, synthetic dyes are non‐covalently added to polymers for fluorescent tracking, but often diffuse away. Here we demonstrate, for the first time, a facile method for the synthesis of fluorescent poly(lactic acid) nano‐/microfibres for biomedical applications using solution spin blowing. Pyrene‐end‐capped poly(l ‐lactide) (PLLA) derivatives were synthesised using the ring‐opening polymerisation of l ‐lactide and they were characterised using spectroscopic and thermal analyses. Submicrometre‐sized fluorescent fibres were produced from these PLLA derivatives using solution blow spinning techniques generating polymer blends and core–shell fibres. Such system could be further exploited to incorporate electrically conductive carbon allotropes via the pyrene aromaticity, producing fluorescent and electrically active fibres for in vitro monitoring and electrical stimulation. © 2018 Society of Chemical Industry     

Polylactide‐perylene derivative for blue biodegradable organic light‐emitting diodes

In this work we demonstrate, for the first time, the use of polylactic acid (PLA) as a biodegradable host matrix for the construction of the active emissive layer of organic light‐emitting diode (OLED) devices for potential use in bioelectronics. In this preliminary study, we report a robust synthesis of two fluorescent PLA derivatives, pyrene‐PLA ( AH10 ) and perylene‐PLA ( AH11 ). These materials were prepared by the ring opening polymerisation of l ‐lactide with hydroxyalkyl‐pyrene and hydroxyalkyl‐perylene derivatives using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as catalyst. OLEDs were fabricated from these materials using a simple device architecture involving a solution‐processed single‐emitting layer in the configuration ITO/PEDOT:PSS/PVK:OXD‐7 (35%): AH10 or AH11 (20%)/TPBi/LiF/Al (ITO, indium tin oxide; PEDOT:PSS, poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonic acid); PVK, poly(vinylcarbazole); OXD‐7, (1,3‐phenylene)‐bis‐[5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole]; TPBi, 2,2′,2″‐(1,3,5‐benzenetriyl)tris(1‐phenyl‐1H‐benzimidazole)). The turn‐on voltage for the perylene OLED at 10 cd m^–2 was around 6 V with a maximum brightness of 1200 cd m^–2 at 13 V. The corresponding external quantum efficiency and device current efficiency were 1.5% and 2.8 cd A^–1 respectively. In summary, this study provides proof of principle that OLEDs can be constructed from PLA, a readily available and renewable bio‐source. © 2020 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.     

Heuristic Methods for Minimum-Cost Pipeline Network Design – a Node Valency Transfer Metaheuristic

Designing low-cost network layouts is an essential step in planning linked infrastructure. For the case of capacitated trees, such as oil or gas pipeline networks, the cost is usually a function of both pipeline diameter (i.e. ability to carry flow or transferred capacity) and pipeline length. Even for the case of incompressible, steady flow, minimizing cost becomes particularly difficult as network topology itself dictates local flow material balances, rendering the optimization space non-linear. The combinatorial nature of potential trees requires the use of graph optimization heuristics to achieve good solutions in reasonable time. In this work we perform a comparison of known literature network optimization heuristics and metaheuristics for finding minimum-cost capacitated trees without Steiner nodes, and propose novel algorithms, including a metaheuristic based on transferring edges of high valency nodes. Our metaheuristic achieves performance above similar algorithms studied, especially for larger graphs, usually producing a significantly higher proportion of optimal solutions, while remaining in line with time-complexity of algorithms found in the literature. Data points for graph node positions and capacities are first randomly generated, and secondly obtained from the German emissions trading CO₂ source registry. As political will for applications and storage for hard-to-abate industry CO₂ emissions is growing, efficient network design methods become relevant for new large-scale CO₂ pipeline networks.

     

A technique for measuring bronchial mucociliary clearance in unsedated dogs

An unsedated dog model of bronchial mucociliary clearance was developed using radioaerosol techniques. A neutralized, concentrated, monodisperse iron oxide aerosol (5–6 μm MMAD) radiotagged with technetium-99m was delivered to the dog via a face mask. Retained activity was measured while the dog was restrained in front of a gamma camera. Measurements were made for 2–3 h post-inhalation and again at 24 h. Three beagle dogs, each studied four times, demonstrated mean percents for 2 h particle retention within the whole lung of 76 ± 13, 92 ± 7 and 89 ± 4, within the bronchial airways of 48 ± 27, 84 ± 15 and 73 ± 10, and mean 24 h particle retentions of 47 ± 18, 65 ± 11 and 57 ± 9, respectively. The unsedated beagle dog provides a potential model for study of the effects of drugs, disease and inhaled pollutants on mucociliary transport.     

Parent-child interactions during the initial weeks following brain injury in young children.

Objective: To understand how traumatic brain injury (TBI) affects parent-child interactions acutely following injury. Participants: Young children hospitalized for TBI (n = 80) and orthopedic injuries (OI; n = 113). Method: Raters coded videotaped interactions during free play and structured tasks for parental warmth/responsiveness and negativity and child warmth, behavior regulation, and cooperation. Raters also counted parental directives, critical/restricting statements, and scaffolds. Results: Parents of children with TBI exhibited less warm responsiveness and made more directive statements during a structured task than parents in the OI group. Children with TBI displayed less behavior regulation than children with OI. Parental warm responsiveness was more strongly related to child cooperativeness in the OI group than in the TBI group. Child behavior also mediated group differences in parental responsiveness and directiveness. TBI accounted for as much variance in parental behaviors as or more than did sociodemographic factors. Conclusion: TBI-related changes in child behavior may negatively influence parent-child interactions and disrupt the reciprocity between parent and child. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determination of Gel Point of Epoxy Thermosets via Electric Resistance Measurements

A new, nickel‐coated graphite resistance‐change‐based method for gel‐point determination for epoxy‐based thermoset resins is presented and compared with DSC and rheological methods. Gelation times determined by this new method are in very good agreement with conventional techniques; this new method is potentially simpler and less time consuming than existing ones.

     

Personality differences in attempted suicide versus suicide in adults 50 years of age or older.

The authors tested hypotheses concerning personality differences in treatment-seeking suicide attempters (AT; n = 60) and a community sample of suicides (SU; n = 43) over age 50. On the basis of prior research, the authors hypothesized that SU would be lower in Neuroticism and Openness and higher in Conscientiousness. A 2-group (AT vs. SU) multivariate analysis of covariance with NEO Personality Inventory--Revised (Informant Version) domain scores as dependent variables revealed that SU were lower in Neuroticism and higher in Conscientiousness. The authors conclude that AT and SU in this age group can be distinguished on the basis of informant ratings of personality traits. These differences can inform risk detection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A prospective study of short- and long-term neuropsychological outcomes after traumatic brain injury in children.

Longitudinal neuropsychological outcomes of traumatic brain injury (TBI) were investigated in 53 children with severe TBI, 56 children with moderate TBI, and 80 children with orthopedic injuries only. Neuropsychological functioning was assessed at baseline, at 6- and 12-month follow-ups, and at an extended follow-up (a mean of 4 years postinjury). Mixed model analyses revealed persistent neuropsychological sequelae of TBI that generally did not vary as a function of time postinjury. Some recovery occurred during the first year postinjury, but recovery reached a plateau after that time, and deficits were still apparent at the extended follow-up. Further recovery was uncommon after the first year postinjury. Family factors did not moderate neuropsychological outcomes, despite their demonstrated influence on behavior and academic achievement after childhood TBI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)