Supercritical Assisted Atomization: effect of operative conditions on PVP microparticle size and morphology

2015 ◽  
Vol 97 ◽  
pp. 31-35 ◽  
Author(s):  
S. Liparoti ◽  
R. Adami ◽  
E. Reverchon
Author(s):  
Jean-Pierre Jolivet

This much-anticipated new edition of Jolivet's work builds on the edition published in 2000. It is entirely updated, restructured and increased in content. The book focuses on the formation by techniques of green chemistry of oxide nanoparticles having a technological interest. Jolivet introduces the most recent concepts and modelings such as dynamics of particle growth, ordered aggregation, ionic and electronic interfacial transfers. A general view of the metal hydroxides, oxy-hydroxides and oxides through the periodic table is given, highlighting the influence of the synthesis conditions on crystalline structure, size and morphology of nanoparticles. The formation of aluminum, iron, titanium, manganese and zirconium oxides are specifically studied. These nanomaterials have a special interest in many technological fields such as ceramic powders, catalysis and photocatalysis, colored pigments, polymers, cosmetics and also in some biological or environmental phenomena.


RSC Advances ◽  
2015 ◽  
Vol 5 (18) ◽  
pp. 13331-13340 ◽  
Author(s):  
T. N. Ng ◽  
X. Q. Chen ◽  
K. L. Yeung

Flow-synthesis of mesoporous silica allows deliberate and precise control over the size and shapes and enables the preparation of complex microstructures (i.e., hollow spheres).


Lab on a Chip ◽  
2014 ◽  
Vol 14 (15) ◽  
pp. 2709-2716 ◽  
Author(s):  
Xue-Ying Wang ◽  
Zi-He Jin ◽  
Bo-Wen Gan ◽  
Song-Wei Lv ◽  
Min Xie ◽  
...  

We engineer interconnected 3D vascular networks in hydrogels using molded sodium alginate lattice as sacrificial templates. The size and morphology of simulated vascular networks were well controlled and a fully-developed endothelial layer was formed.


RSC Advances ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 20708-20719
Author(s):  
Magdalena Kulpa-Greszta ◽  
Anna Tomaszewska ◽  
Andrzej Dziedzic ◽  
Robert Pązik

Rapid hot-injection can be used for precise control of magnetic particle shape.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helena Bestová ◽  
Jules Segrestin ◽  
Klaus von Schwartzenberg ◽  
Pavel Škaloud ◽  
Thomas Lenormand ◽  
...  

AbstractThe Metabolic Scaling Theory (MST), hypothesizes limitations of resource-transport networks in organisms and predicts their optimization into fractal-like structures. As a result, the relationship between population growth rate and body size should follow a cross-species universal quarter-power scaling. However, the universality of metabolic scaling has been challenged, particularly across transitions from bacteria to protists to multicellulars. The population growth rate of unicellulars should be constrained by external diffusion, ruling nutrient uptake, and internal diffusion, operating nutrient distribution. Both constraints intensify with increasing size possibly leading to shifting in the scaling exponent. We focused on unicellular algae Micrasterias. Large size and fractal-like morphology make this species a transitional group between unicellular and multicellular organisms in the evolution of allometry. We tested MST predictions using measurements of growth rate, size, and morphology-related traits. We showed that growth scaling of Micrasterias follows MST predictions, reflecting constraints by internal diffusion transport. Cell fractality and density decrease led to a proportional increase in surface area with body mass relaxing external constraints. Complex allometric optimization enables to maintain quarter-power scaling of population growth rate even with a large unicellular plan. Overall, our findings support fractality as a key factor in the evolution of biological scaling.


1963 ◽  
Vol 41 (5) ◽  
pp. 881-888 ◽  
Author(s):  
Hilda Lei Ching

Maritrema laricola sp. n. from the intestine of the glaucous-winged gull, Larus glaucescens, differs from other species in the genus in having an elongate body, small cirrus sac, and short, curved cirrus. The life cycle of the species was followed from sporocyst stage in Littorina scutulata and Littorina sitchana, to the metacercarial stage in Hemigrapsus oregonensis and H. nudus, and to the adult in natural and experimental hosts. In experimental infections of H. oregonensis, the cercariae penetrate and develop in the gills after which they migrate to the haemocoel of the crab and encyst. The metacercariae are fully developed in from 6 to 9 weeks, and similar in size and morphology to natural infections in crabs. Excystment of the metacercariae occurs in the following cultures at 40 °C: 3% pepsin plus 1% HCl, 0.85% saline, and seawater diluted 1:4. Metacercariae live for about 3 days in diluted seawater but do not produce eggs in any of the cultures. Only immature worms were recovered from mice and newly hatched chicks when they were fed the metacercariae, but mature worms were found in natural and experimental infections of the glaucous-winged gull. In a review of the genus Maritrema, the following transfers are made: Maritrema uca Sarkisian, 1957 to the genus Mecynophallus Cable, Connor, and Balling, 1960, and Maritreminoides raminellae Dery, 1958 to Pseudospelotrema Yamaguti, 1939.


2021 ◽  
Vol 14 (6) ◽  
pp. 562
Author(s):  
Mauro Banchero

Cyclodextrins are widely used in pharmaceutics to enhance the bioavailability of many drugs. Conventional drug/cyclodextrin complexation techniques suffer from many drawbacks, such as a high residual content of toxic solvents in the formulations, the degradation of heat labile drugs and the difficulty in controlling the size and morphology of the product particles. These can be overcome by supercritical fluid technology thanks to the outstanding properties of supercritical CO2 (scCO2) such as its mild critical point, its tunable solvent power, and the absence of solvent residue after depressurization. In this work the use of scCO2 as an unconventional medium to achieve the complexation with native and substituted cyclodextrins of over 50 drugs, which belong to different classes, are reviewed. This can be achieved with different approaches such as the “supercritical solvent impregnation” and “particle-formation” techniques. The different techniques are discussed to point out how they affect the complexation mechanism and efficiency, the physical state of the drug as well as the particle size distribution and morphology, which finally condition the release kinetics and drug bioavailability. When applicable, the results obtained for the same drug with various cyclodextrins, or different complexation techniques are compared with those obtained with conventional approaches.


Author(s):  
John R. D. Hervey ◽  
Paolo Bombelli ◽  
David J. Lea-Smith ◽  
Alan K. Hulme ◽  
Nathan R. Hulme ◽  
...  

AbstractAbsorption spectroscopy is widely used to determine absorption and transmission spectra of chromophores in solution, in addition to suspensions of particles, including micro-organisms. Light scattering, caused by photons deflected from part or all of the cells or other particles in suspension, results in distortions to the absorption spectra, lost information and poor resolution. A spectrophotometer with an integrating sphere may be used to alleviate this problem. However, these instruments are not universally available in biology laboratories, for reasons such as cost. Here, we describe a novel, rapid, and inexpensive technique that minimises the effect of light scattering when performing whole-cell spectroscopy. This method involves using a custom made dual compartment cuvette containing titanium dioxide in one chamber as a scattering agent. Measurements were conducted of a range of different photosynthetic micro-organisms of varying cell size and morphology, including cyanobacteria, eukaryotic microalgae and a purple non-sulphur bacterium. A concentration of 1 mg ml−1 titanium dioxide, using a spectrophotometer with a slit width of 5 nm, produced spectra for cyanobacteria and microalgae similar (1–4% difference) to those obtained using an integrating sphere. The spectrum > 520 nm was similar to that with an integrating sphere with the purple non-sulphur bacterium. This system produced superior results to those obtained using a recently reported method, the application of the diffusing agent, Scotch™ Magic tape, to the side of the cuvette. The protocol can be completed in an equivalent period of time to standard whole-cell absorbance spectroscopy techniques, and is, in principle, suitable for any dual-beam spectrophotometer.


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