94 research outputs found
Two methods of obtaining sol gel Nb2O5 thin films for electrochromic devices
Nb2O5 coatings prepared by the sol-gel route using the dip coating technique with sols prepared from alkoxide or chloroalkoxide (two different methods: sonocatalytic and conventional) precursors are a promising alternative for WO3 electrochromic coatings. The crystalline films (TT phase) sintered at 560 and 600 degrees C are transparent and present a deep blue colour under Li+ ion insertion. Electrochemical stability is excellent as these systems are fully reversible and stable and no change in colour, amount of charge exchanged and corrosion effect could be observed after 2000 voltammetry cycles between 2 and - 1.8 V versus Ag. The electrochemical and optical properties of these coatings have been determined as a function of sintering temperature. The superficial structure was visualized by atomic force microscopy (AFM) and scanning electron microscopy (SEM) and the Li+ diffusion coefficient was determined for both kinds of coatings
Two methods of obtaining sol gel Nb2O5 thin films for electrochromic devices
Nb2O5 coatings prepared by the sol-gel route using the dip coating technique with sols prepared from alkoxide or chloroalkoxide (two different methods: sonocatalytic and conventional) precursors are a promising alternative for WO3 electrochromic coatings. The crystalline films (TT phase) sintered at 560 and 600 degrees C are transparent and present a deep blue colour under Li+ ion insertion. Electrochemical stability is excellent as these systems are fully reversible and stable and no change in colour, amount of charge exchanged and corrosion effect could be observed after 2000 voltammetry cycles between 2 and - 1.8 V versus Ag. The electrochemical and optical properties of these coatings have been determined as a function of sintering temperature. The superficial structure was visualized by atomic force microscopy (AFM) and scanning electron microscopy (SEM) and the Li+ diffusion coefficient was determined for both kinds of coatings
Polymer electrolytes for electrochromic devices through solvent casting and sol-gel routes
Ionically conductive membranes of gelatin and d-PCL(530)/siloxane doped with cyano-based ionic
liquids (ILs) were prepared through solvent casting and sol-gel methods, respectively. The
membranes were characterized in terms of ionic conductivity, thermal behavior, morphology, and
structure. All samples, except the d-PCL(530)/siloxane matrix, exhibited a predominantly
amorphous morphology. The samples prepared through solvent casting and sol-gel displayed a
minimum thermal stability of 170 and 230 ÂşC, respectively. The ionic conductivity varied
accordingly with the type, quantity, and length of the alkyl chain of the cation of the ILs. The
sample with the highest ionic conductivity was gelatin0.5[C2mim][N(CN)2] with 2.40 x 10-3 S.
cm-1 at 25 ÂşC and 1.68 x 10-2 S. cm-1 at 95 ÂşC. The good results of ionic conductivity encouraged the
assembly and characterization of prototypes of electrochromic devices (ECDs). The best results
were obtained with glass/ITO/WO3/gelatin1[C2mim][SCN]/CeO2-TiO2/ITO/glass configuration that
showed a fast color switching time (~ 15 s) and a good open circuit memory (~ 4 hours). The ECD
changed its color from pale blue to transparent, and its charge density decreased from -17.53 to -
2.71 mC. cm-2 during 640 color/bleaching cycles.This work was supported by Fundação para a Ciência e a Tecnologia (FCT) in the
framework of the Research unit GREEN-it "Bioresources for Sustainability"
(UID/Multi/04551/2013), LaboratĂłrio Associado para a QuĂmica Verde – Tecnologias e Processos
Limpos-LAQV (UID/QUI/50006/2013), grant SRFH/BD/90366/2012 (R.L.) and a contract under
Investigador FCT 2012 program (J.M.S.S.E.). It was also co-financed by FEDER through the
COMPETE Program and PT2020 Partnership Agreement (POCI-01-0145-FEDER – 007265). M.M.
Silva acknowledges CNPq (PVE grant 406617/2013-9) for the mobility grant provided by this
institution. A. Pawlicka and R.C. Sabadini acknowledge CNPq (grant 305029/2013-4 and
152252/2016-9), and F.C. Sentanin acknowledges CAPES (grant PNPD20131739- 33002045017P6).info:eu-repo/semantics/publishedVersio
New methods of varicose veins treatment
Chronic venous disease may affect even 60% of the population. Manifestation of this condition may vary from no symptoms to an active venous ulcer. The treatment of this disease may improve patient’s quality of life. A large number of new studies have been carried out since the guidelines publication of the Society for Vascular Surgery, American Venous Forum and European Society for Vascular Surgery considering chronic venous disease treatment. There is also available a 2 year follow-up of the study described in the guidelines. New non- thermal techniques like Mechanochemical ablation (MOCA) and Cyanoacrylate closure (CAC) are very effective, less painful and safe. The use of endovenous non- thermal ablation techniques doesn’t require tumescent anaesthesia which works as a heat sink protecting surrounding tissues from damage in thermal techniques. This eliminates the risk of bleeding and pain associated with multiple needle injections along the vein section to be treated. New studies show that MOCA and CAC techniques have high closure rates directly after the procedure and in the follow-up periods
Vitamin D and hypertension
Introduction: Current epidemiological studies indicate, that insufficiency of vitamin D affects 50% of the population worldwide. 1α,25(OH)2D – active form of vitamin D affects tissues and organs through vitamin D receptor (VDR). Attention to the role of vitamin D deficiency in hypertension development has been continuously increased during recent decades.
The aim of the study: The purpose of this narrative systemic review was to analyse and summarize available data on role of vitamin D deficiency in hypertension development.
Material and method: Standard criteria were used to review the literature data. The search of articles in the PubMed and Google Scholar database was carried out using the following keywords: hypertension, calcitriol, vitamin D, 25-hydroxyvitamin D.
Description of the state of knowledge: Vitamin D influence blood pressure level through renin-angiotensin-aldosterone system (RAAS) and parathormon regulation. Studies conducted on animal model could explain possible mechanism of vitamin D influence on blood pressure control. However, clinical trial results are equivocal due to differences in sample size, heterogeneity of patient baseline characteristics, different vitamin D doses and study duration.
Summary: Further research is needed to confirm the role of vitamin D in hypertension development
To continue or discontinue aspirin? The risk of perioperative complications
Acetylsalicylic acid (aspirin) is a noncompetitive irreversible antagonist of the enzyme cyclooxygenase 1 (COX1). This drug is commonly used in prevention of cardiovascular and cerebrovascular events due to inhibition of platelet function. Because of the risk of surgical hemorrhage it is recommended to cessation aspirin intake couple days before the surgical intervention. However, discontinuation of aspirin treatment may results in increased risk of thrombotic events and perioperative complications. Antithrombotic Trialist's Collaboration proved that low dose of aspirin intake before surgery reduces the risk of nonfatal myocardial infarction by 33%, vascular events by 17% and nonfatal stroke by 25%. However, some studies showed the increased risk of perioperative bleeding in patients continuing aspirin treatment. The position of experts is not unambiguous and there have been doubts about the necessity of discontinuation or continuation this drug before surgery
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