92 research outputs found
Tunable distribution of silica nanoparticles in water-borne coatings via strawberry supracolloidal dispersions
Hypothesis: Water-borne coatings are rapidly expanding as sustainable alternatives to organic solvent-borne systems. Inorganic colloids are often added to aqueous polymer dispersions to enhance the performance of water-borne coatings. However, these bimodal dispersions have many interfaces which can result in unstable colloids and undesirable phase separation. The covalent bonding between individual colloids, on a polymer-inorganic core-corona supracolloidal assembly, could reduce or suppress instability and phase separation during drying of coatings, advancing its mechanical and optical properties. Methods: Aqueous polymer-silica supracolloids with a core-corona strawberry configuration were used to precisely control the silica nanoparticles distribution within the coating. The interaction between polymer and silica particles was fine-tuned to obtain covalently bound or physically adsorbed supracolloids. Coatings were prepared by drying the supracolloidal dispersions at room temperature, and their morphology and mechanical properties were interconnected. Findings: Covalently bound supracolloids provided transparent coatings with a homogeneous 3D percolating silica nanonetwork. Supracolloids having physical adsorption only, resulted in coatings with a stratified silica layer at interfaces. The well-arranged silica nanonetworks strongly improve the storage moduli and water resistance of the coatings. These supracolloidal dispersions offer a new paradigm for preparing water-borne coatings with enhanced mechanical properties and other functionalities, like structural color.</p
NanocompĂłsitos de matriz polimĂ©rica: estratĂ©gias de sĂntese de materiais hĂbridos
In-situ liquid phase imaging of block copolymer vesicle assembly
Amphiphilic block copolymers in aqueous solution can assemble into various ordered molecular architectures,
which have a wide range of applications in, for example, drug delivery and catalytic nanoreactors.1 While sustained efforts, both experimentally and theoretically, have been made to better understand the mechanism of self- assembly in order to gain more control over this process,2, 3 there has never been a real-time, real space investigation of the assembly process on the nanoscale. Here we show the first observation of block copolymer vesicle assembly via the solvent switch protocol4 using liquid phase transmission electron microscopy (LP-TEM). We also discuss the different mechanisms of self-assembly with the ex-situ cryo-TEM observation and compare them with self-consistent field (SCF) lattice calculations. Our findings illustrate the ability of LP-TEM to implement quantitative visualization of local formation process of the block copolymer vesicles to reveal the formation mechanism on an individual particle level
Please click Additional Files below to see the full abstract
International Myeloma Working Group risk stratification model for smoldering multiple myeloma (SMM)
Smoldering multiple myeloma (SMM) is an asymptomatic precursor state of multiple myeloma (MM). Recently, MM
was redefined to include biomarkers predicting a high risk of progression from SMM, thus necessitating a redefinition
of SMM and its risk stratification. We assembled a large cohort of SMM patients meeting the revised IMWG criteria to
develop a new risk stratification system. We included 1996 patients, and using stepwise selection and multivariable
analysis, we identified three independent factors predicting progression risk at 2 years: serum M-protein >2 g/dL (HR:
2.1), involved to uninvolved free light-chain ratio >20 (HR: 2.7), and marrow plasma cell infiltration >20% (HR: 2.4). This
translates into 3 categories with increasing 2-year progression risk: 6% for low risk (38%; no risk factors, HR: 1); 18% for
intermediate risk (33%; 1 factor; HR: 3.0), and 44% for high risk (29%; 2â3 factors). Addition of cytogenetic abnormalities
(t(4;14), t(14;16), +1q, and/or del13q) allowed separation into 4 groups (low risk with 0, low intermediate risk with 1,
intermediate risk with 2, and high risk with â„3 risk factors) with 6, 23, 46, and 63% risk of progression in 2 years,
respectively. The 2/20/20 risk stratification model can be easily implemented to identify high-risk SMM for clinical
research and routine practice and will be widely applicable
Peri-operative red blood cell transfusion in neonates and infants: NEonate and Children audiT of Anaesthesia pRactice IN Europe: A prospective European multicentre observational study
BACKGROUND: Little is known about current clinical practice concerning peri-operative red blood cell transfusion in neonates and small infants. Guidelines suggest transfusions based on haemoglobin thresholds ranging from 8.5 to 12âgâdl-1, distinguishing between children from birth to day 7 (week 1), from day 8 to day 14 (week 2) or from day 15 (â„week 3) onwards. OBJECTIVE: To observe peri-operative red blood cell transfusion practice according to guidelines in relation to patient outcome. DESIGN: A multicentre observational study. SETTING: The NEonate-Children sTudy of Anaesthesia pRactice IN Europe (NECTARINE) trial recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. PATIENTS: The data included 5609 patients undergoing 6542 procedures. Inclusion criteria was a peri-operative red blood cell transfusion. MAIN OUTCOME MEASURES: The primary endpoint was the haemoglobin level triggering a transfusion for neonates in week 1, week 2 and week 3. Secondary endpoints were transfusion volumes, 'delta haemoglobin' (preprocedure - transfusion-triggering) and 30-day and 90-day morbidity and mortality. RESULTS: Peri-operative red blood cell transfusions were recorded during 447 procedures (6.9%). The median haemoglobin levels triggering a transfusion were 9.6 [IQR 8.7 to 10.9] gâdl-1 for neonates in week 1, 9.6 [7.7 to 10.4] gâdl-1 in week 2 and 8.0 [7.3 to 9.0] gâdl-1 in week 3. The median transfusion volume was 17.1 [11.1 to 26.4] mlâkg-1 with a median delta haemoglobin of 1.8 [0.0 to 3.6] gâdl-1. Thirty-day morbidity was 47.8% with an overall mortality of 11.3%. CONCLUSIONS: Results indicate lower transfusion-triggering haemoglobin thresholds in clinical practice than suggested by current guidelines. The high morbidity and mortality of this NECTARINE sub-cohort calls for investigative action and evidence-based guidelines addressing peri-operative red blood cell transfusions strategies. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02350348
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701
Selfâhealing functional surfaces
\u3cp\u3eDuring the last decade extensive research has focused on designing functional surfaces, e.g., with self-cleaning, antibacterial, or antifouling properties, driven by the industrial demand on innovation and sustainability, and the academic interest in new functional materials. Such functionalities are strongly related with surface characteristics, namely chemical composition, physical properties, and topography. Surfaces are, however, dynamic and easily damaged resulting in reduced performance or immediate loss of the functionality. Damage is ubiquitous, hence incorporating self-healing mechanisms allows repairing the functionalities while maintaining a high performance with extended service lifetime. Polymeric surfaces are particularly relevant for functional materials, covering the large majority of devices that are currently used. However, due to their chemical nature, they are typically soft and vulnerable to damages. This report covers the most recent advances concerning self-healing functional surfaces. Low adherence polymeric surfaces are addressed. Further then recovering chemical composition only, additional challenges raised by the recovery of other surface features, such as roughness, porosity, or heterogeneity, are considered. The impact of inherent surface dynamics on the recovery of surface functionalities is discussed, the limitations are highlighted and alternatives are suggested. The recent progress on self-healing of reversible and responsive surfaces is addressed and future research directions for self-healing functional surfaces are anticipated.\u3c/p\u3
Trapping water from desert fog
A coated cotton fabric can absorb more than 3 times its weight in water from warm, moist air, and release it again at higher temperatures.
John Xin at the Hong Kong Polytechnic University in China, Catarina Esteves at Eindhoven University of Technology in the Netherlands and their colleagues grafted a temperature-sensitive polymer onto cotton fabric. At 16â25 °C, the polymer chains interact to form a porous, sponge-like network that traps water. At higher temperatures, the material shrinks and releases its moisture in a cycle that is reversible. The material could be useful in dry, desert areas to collect water from morning dew or fog, the authors say. Adv. Mater. http://dx.doi.org/10.1002/adma.201204278 (2013
Mist oogsten in de woestijn
Water winnen in de woestijn, uit mist of zelfs uit lucht : onderzoekers van de TU Eindhoven maakten een materiaal waarmee dat heel goed lukt. door Karel Kni
Influence of experimental parameters on the formation and stability of silica-wax colloidosomes
\u3cp\u3eHypothesis: Silica-wax colloidosomes find application in various fields, for instance through their use as microencapsules for triggered release of chemical components or as precursors for the production of Janus particles. The characteristics of these colloidosomes are highly dependent on the particles/water-oil system composition and experimental parameters. Experiments: Different colloidosomes were prepared using silica particles (DÂŻ â 295 nm) and a positively charged surfactant (cetyltrimethylammonium bromide, CTAB) as co-stabilizers of a wax in water. The CTAB concentration, type of stirring and wax addition procedure were systematically varied. The silica particles and colloidosomes formed were analysed by Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS). The final percentage of the silica particles embedded on the wax colloidosomes (embedding yield) was estimated by a gravimetric method and the formation of monolayer or multilayer/clusters of silica particles at the wax surface was inspected with SEM. Findings: The CTAB concentration and the wax addition procedure play a major role in obtaining an embedding yield close to 100% and a monolayer coverage of the colloidosomes surface. The results indicate the existence of a mechanism consisting of a dynamic redistribution of the surfactant between the interfaces present in the emulsion. The practical and theoretical insights provided can be used towards an efficient production and scale-up of silica-wax colloidosomes.\u3c/p\u3
- âŠ