Electro-active nanofibres electrospun from blends of poly-vinyl cinnamate and a cholesteric liquid crystalline silicone polymer

Electrospinning was used to generate polymer nanofibres from blends of poly-vinyl cinnamate (PVCN) and a cholesteric silicone polymer. Only blends that contained at least 40 % of PVCN produced fibres. Both differential scanning calorimetry and electron dispersion spectroscopy data indicate that the samples are miscible over a wide temperature interval. The variation of fibre diameter with concentration is nonlinear with a well-defined minimum corresponding to an 80 % PVCN blend. The fibres are birefringent with Kerr constants similar to that of cholesteric liquid crystals. Although not significant, the Kerr constant increases with increasing silicone polymer concentration

Shear suppression of crystal nucleation in a low molar mass compound/polymer solution

The move towards a de-carbonized world, driven partly by climate science and partly by the business opportunities it offers, will need the promotion of environmentally friendly alternatives, if an acceptable stabilization level of atmospheric carbon dioxide is to be achieved. This requires the harnessing and use of natural resources that produce no air pollution or greenhouse gases and provides comfortable coexistence of human, livestock, and plants. This article presents a comprehensive review of energy sources, and the development of sustainable technologies to explore these energy sources. It also includes potential renewable energy technologies, efficient energy systems, energy savings techniques and other mitigation measures necessary to reduce climate changes. This article presents a comprehensive review of energy sources, the development of sustainable technologies to explore these energy sources. It also includes potential renewable energy technologies, energy efficiency systems, energy savings techniques and other mitigation measures necessary to reduce climate change. The article concludes with the technical status of the GSHP technologies

Modifying the thermomechanical properties of electrospun fibres of poly‑vinyl cinnamate by photo‑cross‑linking

We explore the effects of cross-linking on some thermal and mechanical properties of polymer nanofibers of poly-vinyl cinnamate which were electro-spun from 1,2 dichloroethane. Scanning electron microscopy performed on the fibres revealed smooth fibres which were devoid of beading or ribbon-type features. When cross-linked, the Young’s moduli and glass transition temperatures of the fibres increase, owing to the formation of new covalent bonds which leads to higher overall binding energies. The glass transition temperatures increased by 20 K after 1 h of photo-polymerization while the Young’s modulus increased by 50% for the same exposure time. The glass transition temperatures as well as the heats of enthalpy indicate that a significant portion of cross-linking occurs within the first 10 min of exposure

Microwave Treatment of Polyacrylonitrile Powder Method Development and Effects of Surface Modification Porosity for Supercapacitor Devices or other Mobile Applications

Acknowledgment: The work at CDRSP was supported by the FCT (Portugal) through Strategic Project - UI 4044.The aim of this article is to develop a method in order to investigate the surface modifications of degraded polyacrylonitrile powders under microwave treatment in air. Microwave treatment of polyacrylonitrile powders in air recorded two stages of degradation firstly an exothermic reaction that started in the range of (86-117)°C. Secondly the Thermal runway here the weight loss reached a peak value between 80-90 percent with the small quantity of 0.25g polyacrylonitrile and in the ashes with a bigger quantity 1g of polyacrylonitrile. Scanning electron microscopy analysis technique revealed the morphological characteristics and the porosity of the carbon compound that may play an important role in the construction of high porosity area and so in electrochemical supercapacitor devices with high performances.info:eu-repo/semantics/publishedVersio

Mismatch-based delayed thrombolysis: a meta-analysis

<p><b>Background and Purpose</b>: Clinical benefit from thrombolysis is reduced as stroke onset to treatment time increases. The use of "mismatch" imaging to identify patients for delayed treatment has face validity and has been used in case series and clinical trials. We undertook a meta-analysis of relevant trials to examine whether present evidence supports delayed thrombolysis among patients selected according to mismatch criteria.</p> <p><b>Methods</b>: We collated outcome data for patients who were enrolled after 3 hours of stroke onset in thrombolysis trials and had mismatch on pretreatment imaging. We selected the trials on the basis of a systematic search of the Web of Knowledge. We compared favorable outcome, reperfusion and/or recanalization, mortality, and symptomatic intracerebral hemorrhage between the thrombolyzed and nonthrombolyzed groups of patients and the probability of a favorable outcome among patients with successful reperfusion and clinical findings for 3 to 6 versus 6 to 9 hours from poststroke onset. Results are expressed as adjusted odds ratios (a-ORs) with 95% CIs. Heterogeneity was explored by test statistics for clinical heterogeneity, I2 (inconsistency), and L’Abbé plot.</p> <p><b>Results</b>: We identified articles describing the DIAS, DIAS II, DEDAS, DEFUSE, and EPITHET trials, giving a total of 502 mismatch patients thrombolyzed beyond 3 hours. The combined a-ORs for favorable outcomes were greater for patients who had successful reperfusion (a-OR=5.2; 95% CI, 3 to 9; I2=0%). Favorable clinical outcome was not significantly improved by thrombolysis (a-OR=1.3; 95% CI, 0.8 to 2.0; I2=20.9%). Odds for reperfusion/recanalization were increased among patients who received thrombolytic therapy (a-OR=3.0; 95% CI, 1.6 to 5.8; I2=25.7%). The combined data showed a significant increase in mortality after thrombolysis (a-OR=2.4; 95% CI, 1.2 to 4.9; I2=0%), but this was not confirmed when we excluded data from desmoteplase doses that were abandoned in clinical development (a-OR=1.6; 95% CI, 0.7 to 3.7; I2=0%). Symptomatic intracerebral hemorrhage was significantly increased after thrombolysis (a-OR=6.5; 95% CI, 1.2 to 35.4; I2=0%) but not significant after exclusion of abandoned doses of desmoteplase (a-OR=5.4; 95% CI, 0.9 to 31.8; I2=0%).</p> <p><b>Conclusions</b>: Delayed thrombolysis amongst patients selected according to mismatch imaging is associated with increased reperfusion/recanalization. Recanalization/reperfusion is associated with improved outcomes. However, delayed thrombolysis in mismatch patients was not confirmed to improve clinical outcome, although a useful clinical benefit remains possible. Thrombolysis carries a significant risk of symptomatic intracerebral hemorrhage and possibly increased mortality. Criteria to diagnose mismatch are still evolving. Validation of the mismatch selection paradigm is required with a phase III trial. Pending these results, delayed treatment, even according to mismatch selection, cannot be recommended as part of routine care.</p&gt

Chotro : Learning from the Indigenous

The Chotro project was established jointly by the Bhasha Research and Publication Centre in Baroda and the European Association for Commonwealth Literature and Language Studies (EACLALS). Founded initially to document the linguistic, literary, and artistic heritage of tribal communities, Bhasha has established an academy for the promotion of tribal studies and the education of the marginalised tribal people of India, the adivasis. Chotro, which emerged from these activities, aimed to situate adivasis in the context of indigenous peoples across the world with whom they have much in common but little, if any, contact. Conceived as a cross-cultural, interdisciplinary forum, Chotro 'brought together' - for that is the meaning of the word in the Bhil language ̶ indigenous people from India and elsewhere with activists and scholars from many countries working in such diverse fields as anthropology, sociology, literature, linguistics, history, music, museum studies, and human rights. Four Chotro gatherings were convened which addressed marginalisation, social deprivation, lack of access to education, loss of traditional lands, knowledge systems, oral traditions, endangered languages, and the representation of the indigenous in performance and the visual arts. Chotro thus illustrated one way in which scholars may contribute to social and cultural activism.El proyecto Chotro se creó en colaboración con el Bhasha Research and Publication Centre, situado en Baroda, y la European Association for Commonwealth Literature and Language Studies (EACLALS). Inicialmente fundado para documentar el legado lingüístico, literario, cultural y artístico de las comunidades tribales, Bhasha ha permitido crear un espacio académico para la promoción de los estudios tribales y la educación de las comunidades tribales marginales en la India, los adivasis. El proyecto Chotro, que creció a raíz de esta actividad, se centró en localizar a los adivasis dentro del contexto de los pueblos indígenas alrededor del mundo, con quienes tienen mucho en común, pero apenas ningún contacto. Concebido como un proyecto intercultural e interdisciplinario, Chotro reunió (haciendo honor a su significado en la lengua bhil) a indígenas procedentes de la India y de otras partes del mundo, así como a activistas y académicos de diversos países especialistas en disciplinas tan diversas como antropología, sociología, literatura, lingüística, historia, música, museología y derechos humanos. Se llevaron a cabo cuatro reuniones en las que se debatió sobre la marginación social, la falta de acceso a la educación, la pérdida de tradiciones, los sistemas de conocimiento, la tradición oral, las lenguas amenazadas y la representación de la población indígena en las artes escénicas y visuales. Gracias al proyecto Chotro los académicos pudieron demostrar su aportación al activismo social y cultural

Highly Anisotropic Polymer Composites Based on Carbon Nanotubes

Properties of polymers can be optimized through processing methods or by the addition of nanofillers. Carbon nanotubes (CNTs) have gained attention due to their promising behavior. Carbon nanotubes are essentially a sheet of graphene wrapped into a cylindrical shape with either a single or multiple walls. Tube diameters are approximately nanometres, but they can be micrometres in length. Due to the unique properties of nanotubes, they offer promise in composite materials with current research dedicated to embedding them in a polymer matrix. If improvements are to be made, the nanotubes need to be in an aligned configuration. This presents challenges due to the strong intermolecular forces that cause nanotube agglomeration leading to poor quality dispersion and random CNT orientations. Thus, there are two particular challenges to the formation of polymer composites based on CNTs: dispersion and alignment, and these are the focus of this chapter. We consider recent developments in the synthesis of carbon nanotubes and their properties. Next, we detail the challenges of dispersion and alignment that are presented in the preparation of polymer/CNT composites. Finally, we review the literature to identify progress made in preparing high performance polymer/CNT composites and their properties and present one particular solution

Carbon nanotubes in electrospun polyethylene oxide nanofibres: a potential route to conducting nanofibres

Polyethylene oxide solution containing multi-walled carbon nanotubes have been electrospun onto a rotating collector to produce highly aligned arrays of electrospun nanofibers ranging in diameters from (200 – 360) nanometres. The addition of a surfactant (Triton X-100)is highly effective in dispersing carbon nanotube within an aqueous solution of polyethylene oxide and the resulting mixture can be electrospun without excessive clumping to produce nanofibers containing high loadings of nanotubes; in this case up to 5% wt thereby providing an effective route to electrically conductive nanofibres

Functionalized coatings by electrospinning for anti-oxidant food packaging

The development of advanced formulations used for food packaging applications, which behave as protection or preservation materials and improve consumers’ health offers a route to reduced food wastage. The present study deals with investigations on the possibility of obtaining functionalized coatings by electrospinning of poly(ɛ-caprolactone), a synthetic biodegradable polymer together with vitamin E (α-tocopherol), selected as plant-based phenolic antioxidant. In this approach electrospinning allows the production of high surface area materials and thus offering an increased antioxidant activity. The electrospun fibres of poly(ɛ-caprolactone)/vitamin E were obtained, studied and their antioxidant properties were evaluated by measuring the fibre reactivity with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The potential for extending the shelf-life of food products by using this approach is discussed