1,251 research outputs found
Plasma surface modification of porous PLLA films: Analysis of surface properties and in vitro hydrolytic degradation
No full textThe aim of this research was to investigate the effects of plasma treatment on the surface and on the in vitro degradation behavior of poly(L-lactide) (PLLA) films. Polymer films were prepared by solvent casting, and their surface was modified by radiofrequency plasma treatments by using oxygen and tetrafluorocarbon gas. Pristine and treated PLLA films were characterized by field emission and atomic force microscopy and by contact angle measurements. In vitro hydrolytic degradation studies were conducted by measurements of weight loss, water absorption, visual inspection, and thermal transitions as a function of the incubation time. As-deposited PLLA films show a uniform distribution of ring-like porous structures on the surface due to solvent evaporation. Plasma treatments produce a mass reduction following the etching of the polymer surface. Moreover, the morphology of the porous polymer is modified by the plasma, which induces different micro/nanometric topographic reliefs as a function of the different selected plasma processing parameters. The results indicate PLLA surface become hydrophilic and the surface roughness increased with treatment time in the case of oxygen, whereas a hydrophobic behavior was induced with tetrafluorocarbon plasma treatment. However, in vitro degradation studies show that plasma treatments do not affect the PLLA bulk and the hydrolytic degradation properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 201
Spin coated cellulose nanocrystal/silver nanoparticle films
No full textAll rights reserved. In this study, thin films of cellulose nanocrystals (CNC) and silver nanoparticles (Ag) were assembled on different substrates by spin coating. The effect of substrates, deposition parameters, and nanocrystal modification on the topographical and hydrophilic properties of the obtained layers was investigated. Dilute concentrations of pristine cellulose nanocrystals (CNC) and surfactant modified crystals (s-CNC) were used in order to evaluate the effect of modification and concentration on the uniformity of the spin coated cellulose/silver layers. Morphological investigations by field emission scanning electron microscopy and atomic force microscopy were performed in order to prove the uniformity of the obtained films, while the wettability of different surfaces were studied and correlated to the cellulose modification and content. The ability of s-CNC to form a stable dispersion in chloroform permits the formation of a uniform cellulose film on the substrate surfaces generating regular films during the spin coating process. Topographical investigations show, on the other hand, that the CNC/Ag suspension produces a non-uniform distribution. These effects can be mainly attributed to the surfactant action rather than to the chemical and electrical properties of the substrate surface. Finally, contact angle studies, underline the hydrophilic nature of s-CNC/Ag based films highlighting that the wettability properties are strongly influenced by the cellulose nanocrystal nature.Peer Reviewe
From the Editor-in-Chief: Changes to Enhance the Author Experience
No full textJMBE Editor-in-Chief, Dr. Samantha Elliott, thanks past volunteers for their efforts and discusses several new author enhancements related to the recently expanded scope, including video tutorials, a self-assessment tool, and a thematic issue
Death Writes: Microbursts & The Clearing: a discussion on text, subject and craft with Elizabeth Reeder and Amanda Thomson - collaborators on microbursts and with Samantha Clark author of The Clearing
No full textDeath Writes is part of the University of Glasgow's interdisciplinary Arts-Lab, Reading and Writing Death and Dying.
Elizabeth Reeder, Amanda Thomson (collaborators on Microbursts) and Samantha Clark (author of The Clearing) will read and talk about their books and the writing, design and editorial processes they underwent. Both books deal with the intense time of being within parental illness, and consider experiences of illness, mental health, parental death, and various types of grief in ways that weave through and utilise artistic and multi-modal processes
Laboratory Exercises for Weather and Climate: Open Education Resource
No full textOER textbook created for PHS 111 by Samantha Langton, PhD.NASUNY DutchessPhysical Sciences, Engineering & TechnologyN/
198 - Samantha Mosier
No full textIncludes bibliographical references.Using pre-commercial thinnings in pine plantations has the potential to deliver sustainable biofuels. However, the removal of biomass from these plantations could reduce C inputs belowground and overall C storage. This study analyzes soil C and N stocks to estimate stock changes, as a function of soil type and different management systems. Soil cores were taken from 12 different southern pine plantations, representing 4 different soil types. Each site had 2 silvicultural regimes across 3 levels of pre-commercial thinning. Soils were separated into meaningful fractions to understand how much soil organic matter is bioavailable and how much is stabilized
Elaborative feedback: Engaging reward and task-relevant brain regions promotes learning in pseudoword reading aloud
No full textAlthough much is known about the cognitive and neural basis of establishing letter-sound mappings in learning word forms, relatively little is known about what makes for the most effective feedback during this process. We sought to determine the neural basis by which elaborative feedback (EF), which contains both reward-related and content-specific information, may be more helpful than feedback containing only one kind of information (simple positive feedback, PF) or the other (content feedback, CF) in learning orthography-phonology (spelling-sound) mappings for novel letter strings. Compared to CF, EF activated the ven- tromedial prefrontal cortex, implicated in reward processing. Compared to PF, EF activated the posterior middle temporal, superior temporal, and supramarginal gyri—regions implicated in orthography-phonology conversion. In the same comparison, EF also activated the left fusiform gyrus/visual word form area—implicated in orthographic processing. Also EF, but not CF or PF, modulated activity in the caudate nucleus. In a postscan questionnaire, EF and PF were rated as more pleasant than CF, suggesting that modulation of the caudate for EF may be due to the coupling of reward and skill content. These findings suggest the enhanced effectiveness of EF may be due to concurrent activation of reward-related and task-relevant brain regions.Peer reviewe
Rehabilitation management of a triceps surae muscle injury in a young male with haemophilia A and high-titre inhibitors
No full textHaemophilia A is a rare inherited hematologic disorder characterized by a deficit of coagulation factor VIII. It is associated with frequent episodes of musculoskeletal bleedings that occur mainly inside joints and secondly inside muscles. The majority of intramuscular hematomas respond well to conservative protocols, based on rehabilitation techniques and appropriate haemostatic coverage; surgery is limited to refractory cases. This manuscript describes the management of an intramuscular bleeding in a young patient with severe haemophilia A and high-titre inhibitors. A multidisciplinary approach directed by a physiatrist and combining surgical intervention, use of bypassing agents and rehabilitation treatment allowed to successfully managing this case, leading to a complete functional recovery. Given the lack of consensus on the treatment of intramuscular bleedings in haemophiliac patients, this case report provides an example of successful management for such conditions, which require a multidisciplinary approach in which the physiatrist plays a key role
Reversing the Standard Neural Signature of the Word–Nonword Distinction
No full textThe distinction between letter strings that form words and those that look and sound plausible but are not meaningful is a basic one. Decades of functional neuroimaging experiments have used this distinction to isolate the neural basis of lexical (word-level) semantics, associated with areas such as the middle temporal, angular, and posterior cingulate gyri that overlap the default-mode network. In two functional magnetic resonance imaging (fMRI) experiments, a different set of findings emerged when word stimuli were used that were less familiar (measured by word frequency) than those typically used. Instead of activating default-mode network areas often associated with semantic processing, words activated task-positive areas such as the inferior prefrontal cortex and supplementary motor area, along with multi-functional ventral occipito-temporal cortices related to reading, while nonwords activated default-mode areas previously associated with semantics. Effective connectivity analyses of fMRI data on less familiar words showed activation driven by task-positive and multi-functional reading-related areas, while highly familiar words showed bottom-up activation flow from occipito-temporal cortex. These findings suggest functional neuroimaging correlates of semantic processing are less stable than previously assumed, with factors such as word frequency influencing the balance between task-positive, reading-related, and default-mode networks. More generally, this suggests results of contrasts typically interpreted in terms of semantic content may be more influenced by factors related to task difficulty than is widely appreciated.Peer reviewed"© 2016 Massachusetts Institute of Technology
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