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Porous Silicon Nanotube Arrays as Anode Material for Li-Ion Batteries. - ACS applied materials & interfaces
We report the electrochemical performance of Si nanotube vertical arrays possessing thin porous sidewalls for Li-ion batteries. Porous Si nanotubes were fabricated on stainless steel substrates using a sacrificial ZnO nanowire template method. These porous Si nanotubes are stable at multiple C-rates. A second discharge capacity of 3095 mAh g(-1) with a Coulombic efficiency of 63% is attained at a rate of C/20 and a stable gravimetric capacity of 1670 mAh g(-1) obtained after 30 cycles. The high capacity values are attributed to the large surface area offered by the porosity of the 3D nanostructures, thereby promoting lithium-ion storage according to a pseudocapacitive mechanism.
Radiation-induced graft polymerization of chitosan onto poly(3-hydroxybutyrate). - Carbohydrate polymers
Chitosan is among the most studied biopolymers and offers important advantages, such as biodegradability, biocompatibility and nontoxicity. In this study, this polysaccharide was grafted onto poly(3-hydroxybutyrate) using the simultaneous gamma-irradiation-initiated polymerization method. The polyester was immersed in diverse solvents, which allowed the preparation of graft copolymers with different yields and crystallinities. A successful synthesis and the estimation of the degree of crystallinity were verified by spectroscopic and calorimetric techniques. The most suitable method was found to be the thermoanalytical approach because it displayed a linear relationship between the degree of crystallinity and the increasing degree of grafting. The results also indicated that the lowest degree of grafting was seen for acetic acid (14.27%), while the highest degree corresponded to ethyl acetate (32.11%). The mechanism of grafting was proposed on the basis of the experimental results.Copyright Â© 2015 Elsevier Ltd. All rights reserved.
Quantifying the Economic and Cultural Biases of Social Media through Trending Topics. - PloS one
Online social media has recently irrupted as the last major venue for the propagation of news and cultural content, competing with traditional mass media and allowing citizens to access new sources of information. In this paper, we study collectively filtered news and popular content in Twitter, known as Trending Topics (TTs), to quantify the extent to which they show similar biases known for mass media. We use two datasets collected in 2013 and 2014, including more than 300.000 TTs from 62 countries. The existing patterns of leader-follower relationships among countries reveal systemic biases known for mass media: Countries concentrate their attention to small groups of other countries, generating a pattern of centralization in which TTs follow the gradient of wealth across countries. At the same time, we find subjective biases within language communities linked to the cultural similarity of countries, in which countries with closer cultures and shared languages tend to follow each other's TTs. Moreover, using a novel methodology based on the Google News service, we study the influence of mass media in TTs for four countries. We find that roughly half of the TTs in Twitter overlap with news reported by mass media, and that the rest of TTs are more likely to spread internationally within Twitter. Our results confirm that online social media have the power to independently spread content beyond mass media, but at the same time social media content follows economic incentives and is subject to cultural factors and language barriers.
One-Year Feasibility Study of Replenish MicroPump for Intravitreal Drug Delivery: A Pilot Study. - Translational vision science & technology
To determine the feasibility of the surgical procedure and to collect some safety data regarding the bioelectronics of a novel micro drug pump for intravitreal drug delivery in a Beagle dog model for up to 1 year.Thirteen Beagle dogs were assigned to two groups. The experimental group (n = 11) underwent pars plana implantation of MicroPump; the body of which was sutured episclerally, while its catheter was secured at a pars plana sclerotomy. The control group (n = 2) underwent sham surgeries in the form of a temporary suturing of the MicroPump, including placement of the pars plana tube. Baseline and follow-up exams included ophthalmic examination and imaging. The experimental animals were euthanized and explanted at predetermined time points after surgery (1, 3, and 12 months), while the control animals were euthanized at 3 months. All operated eyes were submitted for histopathology.Eyes were scored according to a modified McDonald-Shadduck system and ophthalmic imaging. Neither the implanted eyes nor the control eyes showed clinically significant pathological changes beyond the expected surgical changes. The operated eyes showed neither significant inflammatory reaction nor tissue ingrowth through the sclerotomy site compared with the fellow eyes.This study shows that the Replenish Posterior MicroPump could be successfully implanted with good safety profile in this animal model.The results of this study in a Beagle dog model are supportive of the biocompatibility of Replenish MicroPump and pave the way to the use of these devices for ocular automated drug delivery after further testing in larger animal models.
Implantable MicroPump for Drug Delivery in Patients with Diabetic Macular Edema. - Translational vision science & technology
To demonstrate the safety and surgical feasibility of the first-in-man ocular implant of a novel Posterior MicroPump Drug Delivery System (PMP) in patients with diabetic macular edema (DME) and to report on the device capabilities for delivering a programmable microdose.This was a single center, single arm, open-label, prospective study. Eleven patients with DME and visual acuity equal to or worse than 20/40 were included. The PMP prefilled with ranibizumab was implanted into the subconjunctival space. After implantation, the PMP was wirelessly controlled to deliver a programmed microdose. Comprehensive ophthalmic exams and optical coherence tomography were performed biweekly for 90 days. At the end of the study, the PMP was explanted and the subjects thereafter received standard of care for DME (i.e., laser or intravitreal injections).All 11 surgical implantations were without complications and within the skill sets of a retinal surgeon. No serious adverse events occurred during the follow-up period. At no point were visual acuity and central foveal thickness worse than baseline in the implanted eye. The PMP delivered the programmed ranibizumab dosage in seven subjects. The remaining four patients received a lower than target dose, and the treatment was complemented with standard intravitreal injection.This study demonstrates the first-in-man safety of the Replenish MicroPump implant for a period of 90 days and its capability to deliver a microdose into the vitreous cavity. Further studies to enable longer-term safety and to demonstrate the feasibility of multiple programmable drug delivery are necessary.
Treatment of mood disorders in multiple sclerosis. - Current treatment options in neurology
Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system with a significant comorbidity with depressive disorders. Prevalence rates for major depressive disorder (MDD) range from 36Â % to 54Â % and the rate is around 22Â % for adjustment disorders. Selective serotonin reuptake inhibitors (SSRIs) are considered well-tolerated first-line treatment. Tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) are generally reserved for second-line use after SSRIs, because of sedating or anticholinergic side effects. SNRIs, with the exception of duloxetine, and combinations of newer antidepressants have failed to treat depression due to their side effects profile and frequent interaction with other drugs. Among SSRIs, sertraline is usually the first option, starting at 25Â mg/day and increasing to 50Â mg/day; and waiting a few weeks to assess drug effects before increasing the dose. The maximum is generally 200Â mg/day in a single dose. Paroxetine is the second choice, starting at 10Â mg/day for the first 5Â days, and then at 20Â mg/day thereafter. The maximum dose is about 50Â mg/day in a single dose. Fluvoxamine is used at 100-200Â mg/day, starting with 25Â mg/day, and increasing 25Â mg/day every 5Â days until 200Â mg/day is reached. We should take into account increasing blood level amounts of MS treatments (corticosteroids and cyclophosphamide) with fluvoxamine. With duloxetine, doses will be at 60-120Â mg/day. The initial dose for depression is 40Â mg/day in two doses; it can increase to 60Â mg/day in one to two doses if necessary. The maximum dose is generally 120Â mg/day. Duloxetine may increase liver problems through interaction with these MS treatments: teriflunomide, interferon beta-1a, and interferon beta-1b. Considering psychotherapy, only cognitive behavior therapy and mindfulness-based interventions have shown efficacy in improving depression disorders in MS. A comprehensive treatment for depression should include pharmacotherapy and psychotherapy.
Magnetic properties of superparamagnetic nanoparticles loaded into silicon nanotubes. - Nanoscale research letters
In this work, the magnetic properties of silicon nanotubes (SiNTs) filled with Fe3O4 nanoparticles (NPs) are investigated. SiNTs with different wall thicknesses of 10 and 70Â nm and an inner diameter of approximately 50Â nm are prepared and filled with superparamagnetic iron oxide nanoparticles of 4 and 10Â nm in diameter. The infiltration process of the NPs into the tubes and dependence on the wall-thickness is described. Furthermore, data from magnetization measurements of the nanocomposite systems are analyzed in terms of iron oxide nanoparticle size dependence. Such biocompatible nanocomposites have potential merit in the field of magnetically guided drug delivery vehicles.61.46.Fg; 62.23.Pq; 75.75.-c; 75.20.-g.
Pancultural nostalgia: prototypical conceptions across cultures. - Emotion (Washington, D.C.)
Nostalgia is a frequently experienced complex emotion, understood by laypersons in the United Kingdom and United States of America to (a) refer prototypically to fond, self-relevant, social memories and (b) be more pleasant (e.g., happy, warm) than unpleasant (e.g., sad, regretful). This research examined whether people across cultures conceive of nostalgia in the same way. Students in 18 countries across 5 continents (N = 1,704) rated the prototypicality of 35 features of nostalgia. The samples showed high levels of agreement on the rank-order of features. In all countries, participants rated previously identified central (vs. peripheral) features as more prototypical of nostalgia, and showed greater interindividual agreement regarding central (vs. peripheral) features. Cluster analyses revealed subtle variation among groups of countries with respect to the strength of these pancultural patterns. All except African countries manifested the same factor structure of nostalgia features. Additional exemplars generated by participants in an open-ended format did not entail elaboration of the existing set of 35 features. Findings identified key points of cross-cultural agreement regarding conceptions of nostalgia, supporting the notion that nostalgia is a pancultural emotion.
What makes a group worth dying for? Identity fusion fosters perception of familial ties, promoting self-sacrifice. - Journal of personality and social psychology
We sought to identify the mechanisms that cause strongly fused individuals (those who have a powerful, visceral feeling of oneness with the group) to make extreme sacrifices for their group. A large multinational study revealed a widespread tendency for fused individuals to endorse making extreme sacrifices for their country. Nevertheless, when asked which of several groups they were most inclined to die for, most participants favored relatively small groups, such as family, over a large and extended group, such as country (Study 1). To integrate these findings, we proposed that a common mechanism accounts for the willingness of fused people to die for smaller and larger groups. Specifically, when fused people perceive that group members share core characteristics, they are more likely to project familial ties common in smaller groups onto the extended group, and this enhances willingness to fight and die for the larger group. Consistent with this, encouraging fused persons to focus on shared core characteristics of members of their country increased their endorsement of making extreme sacrifices for their country. This pattern emerged whether the core characteristics were biological (Studies 2 and 3) or psychological (Studies 4-6) and whether participants were from China, India, the United States, or Spain. Further, priming shared core values increased the perception of familial ties among fused group members, which, in turn, mediated the influence of fusion on endorsement of extreme sacrifices for the country (Study 5). Study 6 replicated this moderated mediation effect whether the core characteristics were positive or negative. Apparently, for strongly fused persons, recognizing that other group members share core characteristics makes extended groups seem "family like" and worth dying for.
DIMETER: a haptic master device for tremor diagnosis in neurodegenerative diseases. - Sensors (Basel, Switzerland)
In this study, a device based on patient motion capture is developed for the reliable and non-invasive diagnosis of neurodegenerative diseases. The primary objective of this study is the classification of differential diagnosis between Parkinson's disease (PD) and essential tremor (ET). The DIMETER system has been used in the diagnoses of a significant number of patients at two medical centers in Spain. Research studies on classification have primarily focused on the use of well-known and reliable diagnosis criteria developed by qualified personnel. Here, we first present a literature review of the methods used to detect and evaluate tremor; then, we describe the DIMETER device in terms of the software and hardware used and the battery of tests developed to obtain the best diagnoses. All of the tests are classified and described in terms of the characteristics of the data obtained. A list of parameters obtained from the tests is provided, and the results obtained using multilayer perceptron (MLP) neural networks are presented and analyzed.
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