Continuous form-dependent focusing of non-spherical microparticles in a highly diluted suspension with the help of microfluidic spirals

2018 ◽  
Vol 30 (4) ◽  
pp. 045102 ◽  
Author(s):  
Tanja Roth ◽  
Lisa Sprenger ◽  
Stefan Odenbach ◽  
Urs O. Häfeli
Keyword(s):  
Continuous Form ◽  
Spherical Microparticles

scholarly journals Micromechanical Punching: A Versatile Method for Non-Spherical Microparticle Fabrication

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 83
Author(s):  
Ritika Singh Petersen ◽  
Anja Boisen ◽  
Stephan Sylvest Keller
Keyword(s):  
Drug Delivery ◽  
High Resolution ◽  
Physicochemical Properties ◽  
High Throughput ◽  
Liquid State ◽  
Soft Lithography ◽  
Glycolic Acid ◽  
Thermosetting Polymers ◽  
Spherical Microparticle ◽  
Spherical Microparticles

Microparticles are ubiquitous in applications ranging from electronics and drug delivery to cosmetics and food. Conventionally, non-spherical microparticles in various materials with specific shapes, sizes, and physicochemical properties have been fabricated using cleanroom-free lithography techniques such as soft lithography and its high-resolution version particle replication in non-wetting template (PRINT). These methods process the particle material in its liquid/semi-liquid state by deformable molds, limiting the materials from which the particles and the molds can be fabricated. In this study, the microparticle material is exploited as a sheet placed on a deformable substrate, punched by a robust mold. Drawing inspiration from the macro-manufacturing technique of punching metallic sheets, Micromechanical Punching (MMP) is a high-throughput technique for fabrication of non-spherical microparticles. MMP allows production of microparticles from prepatterned, porous, and fibrous films, constituting thermoplastics and thermosetting polymers. As an illustration of application of MMP in drug delivery, flat, microdisk-shaped Furosemide embedded poly(lactic-co-glycolic acid) microparticles are fabricated and Furosemide release is observed. Thus, it is shown in the paper that Micromechanical punching has potential to make micro/nanofabrication more accessible to the research and industrial communities active in applications that require engineered particles.

scholarly journals Thermal and Mechanical Behavior of Elastomers Incorporated with Thermoregulating Microcapsules

2021 ◽  
Vol 11 (12) ◽  
pp. 5370
Author(s):  
Ana M. Borreguero ◽  
Irene Izarra ◽  
Ignacio Garrido ◽  
Patrycja J. Trzebiatowska ◽  
Janusz Datta ◽  
...  
Keyword(s):  
Latent Heat ◽  
Continuous Improvement ◽  
Low Density Polyethylene ◽  
Molar Ratio ◽  
Low Density ◽  
Minimum Particle Size ◽  
Synergy Effects ◽  
Elastomeric Materials ◽  
The Matrix ◽  
Spherical Microparticles

Polyurethane (PU) is one of the principal polymers in the global plastic market thanks to its versatility and continuous improvement. In this work, PU elastomeric materials having thermoregulating properties through the incorporation of microcapsules (mSD-(LDPE·EVA-RT27)) from low-density polyethylene and vinyl acetate containing paraffin®RT27 as PCM were produced. Elastomers were synthesized while varying the molar ratio [NCO]/[OH] between 1.05 and 1.1 and the microcapsule (MC) content from 0.0 to 20.0 wt.%. The successful synthesis of the PUs was confirmed by IR analyses. All the synthesized elastomers presented a structure formed by a net of spherical microparticles and with a minimum particle size for those with 10 wt.% MC. The density and tensile strength decreased with the MC content, probably due to worse distribution into the matrix. Elastomer E-1.05 exhibited better structural and stability properties for MC contents up to 15 wt.%, whereas E-1.1, containing 20 wt.% MC, revealed mechanical and thermal synergy effects, demonstrating good structural stability and the largest latent heat. Hence, elastomers having a large latent heat (8.7 J/g) can be produced by using a molar ratio [NCO]/[OH] of 1.1 and containing 20 wt.% mSD-(LDPE·EVA-RT27).

scholarly journals Visible and near-infrared backscattering spectroscopy for sizing spherical microparticles

2007 ◽  
Vol 46 (1) ◽  
pp. 67 ◽  
Author(s):  
Lucía B. Scaffardi ◽  
Fabián A. Videla ◽  
Daniel C. Schinca
Keyword(s):  
Near Infrared ◽  
Spherical Microparticles

Heat Treatment of Nanostructured Powders Obtained by Spark Erosion of WC-8Co Cemented Carbide in Oil

2020 ◽  
Vol 312 ◽  
pp. 297-302
Author(s):  
M.I. Dvornik ◽  
Elena A. Mikhailenko
Keyword(s):  
Heat Treatment ◽  
Specific Energy Consumption ◽  
Average Diameter ◽  
Rapid Crystallization ◽  
Excess Carbon ◽  
Spark Erosion ◽  
Chemical And Phase Compositions ◽  
Process Productivity ◽  
Spherical Microparticles ◽  
Nanostructured Powders

Spark erosion of WC-8Co carbide pieces in oil resulted in a powder consisting of nanostructured spherical microparticles formed by rapid crystallization of the melt. These particles consist of rounded WC grains with an average diameter of about 0.18 μm, surrounded by cobalt. The process productivity, specific energy consumption, microstructure, particle size distribution, chemical and phase compositions of the obtained powder are determined. It was found that as a result of oil pyrolysis, free carbon is formed (3.4 %), which makes this powder unsuitable for the production of carbide products from it. A technique has been developed and the process of controlled removal of excess carbon by annealing the obtained powder in a CO2 atmosphere at a temperature of 1000 °C has been studied. As a result of annealing for 120 minutes, the carbon content decreases to the required value (5.6 %). Studies of the phase composition and microstructure showed that the obtained particles consist of elongated WC grains, the average diameter of which increased to 0.43 μm.

scholarly journals Time evolution of restless legs syndrome in haemodialysis patients

2019 ◽  
Author(s):  
Irene Capelli ◽  
Fabio Pizza ◽  
Marco Ruggeri ◽  
Lorenzo Gasperoni ◽  
Elisa Carretta ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Kidney Transplantation ◽  
Restless Legs Syndrome ◽  
Statistical Significance ◽  
Dialysis Patients ◽  
Restless Legs ◽  
Continuous Form ◽  
Over Time

Abstract Background Restless legs syndrome (RLS) is characterized by an urge to move the extremities, accompanied by paraesthesiae, in the evening and at night. Uraemic RLS, a type of secondary RLS, occurs commonly in chronic kidney disease and end-stage renal disease. Progression of uraemic RLS over time is unclear. Therefore we investigated the prevalence, progression over time, risk factors and impact on survival of uraemic RLS in a cohort of dialysis patients. Methods We reviewed at the 7-year follow-up a cohort of haemodialysis (HD) patients we had previously investigated for RLS, through interviews, validated questionnaires and analysis of demographic and clinical data. Results At the 7-year follow-up, RLS was present in 16% of patients, with a persistence rate of 33%. A correlation was obtained between RLS and older age, diabetes, low albumin and low body mass index. RLS was associated with reduced overall survival (median survival of 3.3 versus 3.7 years), particularly with the continuous form of RLS (1.61 years). There was a higher incidence of myocardial infarction and peripheral vascular disease, although not reaching statistical significance. RLS patients had absolute higher scores in all quality of life domains. A large majority of study patients (96%) reported being symptom-free within a few days or weeks following kidney transplantation. Conclusions The development of RLS, especially the continuous form, in patients undergoing HD has important consequences associated with decreased survival. Our results indicated an association between uraemic RLS and ageing, diabetes and malnutrition. Considerable efforts should be focused on the treatment of RLS, since it significantly and persistently impacts the quality of life of HD patients. Kidney transplantation could represent an effective treatment option for that RLS impacts on dialysis patients' quality of life, thus confirming the secondary nature of RLS in most HD patients.

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