Stable Amorphous Danazol Nanostructured Powders with Rapid Dissolution Rates Produced by Spray Freezing into Liquid

AbstractAntarctic calcified macroorganisms are particularly vulnerable to ocean acidification because many are weakly calcified, the dissolution rates of calcium carbonate are inversely related to temperature, and high latitude seas are predicted to become undersaturated in aragonite by the year 2100. We examined the post-mortem dissolution rates of aragonitic and calcitic shells from four species of Antarctic benthic marine invertebrates (two bivalves, one limpet, one brachiopod) and the thallus of a limpet shell-encrusting coralline alga exposed to acidified pH (7.4) or non-acidified pH (8.2) seawater at a constant temperature of 4°C. Within a period of only 14–35 days, shells of all four species held in pH 7.4 seawater had suffered significant dissolution. Despite calcite being 35% less soluble in seawater than aragonite, there was surprisingly, no consistent pattern of calcitic shells having slower dissolution rates than aragonitic shells. Outer surfaces of shells held in pH 7.4 seawater exhibited deterioration by day 35, and by day 56 there was exposure of aragonitic or calcitic prisms within the shell architecture of three of the macroinvertebrate species. Dissolution of coralline algae was confirmed by differences in weight loss in limpet shells with and without coralline algae. By day 56, thalli of the coralline alga held in pH 7.4 displayed a loss of definition of the conceptacle pores and cracking was evident at the zone of interface with limpet shells. Experimental studies are needed to evaluate whether there are adequate compensatory mechanisms in these and other calcified Antarctic benthic macroorganisms to cope with anticipated ocean acidification. In their absence, these organisms, and the communities they comprise, are likely to be among the first to experience the cascading impacts of ocean acidification.

Download Full-text

Gypsum solubility in seawater, and its application to bauxite residue amelioration

Soil Research ◽

10.1071/sr04034 ◽

2004 ◽

Vol 42 (8) ◽

pp. 953 ◽

Cited By ~ 19

Author(s):

P. M. Kopittke ◽

N. W. Menzies ◽

I. M. Fulton

Keyword(s):

Bauxite Residue ◽

Field Application ◽

Dissolution Rates ◽

Gypsum Dissolution ◽

Ionic Strength Effect ◽

First Order ◽

First Order Kinetics ◽

Rapid Dissolution ◽

Dissolution Rate Constants ◽

Strength Effect

The solubilities and dissolution rates of 3 gypsum sources [analytical grade reagent (AR), phosphogypsum (PG), mined gypsum (MG)] with 6 MG size fractions (>2.0, 1.0–2.0, 0.5–1.0, 0.25–0.5, 0.125–0.25, <0.125 mm) were investigated in triple-deionised water (TDI) and seawater to examine their suitability for bauxite residue amelioration. Gypsum solubility was greater in seawater (3.8 g/L) than TDI (2.9 g/L) due to the ionic strength effect, with dissolution in both TDI and seawater following first-order kinetics. Dissolution rate constants varied with gypsum source (AR > PG > MG) due to reactivity and surface area differences, with 1 : 20 gypsum : solution suspensions reaching saturation within 15 s (AR) to 30 min (MG >2.0 mm). The ability of bauxite residue to adsorb Ca from solution was also examined. The quantity of the total solution Ca adsorbed was found to be small (5%). These low rates of solution Ca adsorption, combined with the comparatively rapid dissolution rates, preclude the application of gypsum to the residue sand/seawater slurry as a method for residue amelioration. Instead, direct field application to the residue would ensure more efficient gypsum use. In addition, the formation of a sparingly soluble CaCO3 coating around the gypsum particles after mixing in a highly alkaline seawater/supernatant liquor solution greatly reduced the rate of gypsum dissolution.

Download Full-text

Mechanism of cholesterol monohydrate dissolution in taurocholate-lecithin media—Correlation between equilibrium dialysis results and dissolution rates

Journal of Colloid and Interface Science ◽

10.1016/s0021-9797(84)80004-1 ◽

1984 ◽

Vol 98 (1) ◽

pp. 9-19

Author(s):

W HIGUCHI ◽

C SU ◽

N DAABIS ◽

A WANICHSIRIROJ ◽

A HOFMANN

Keyword(s):

Equilibrium Dialysis ◽

Dissolution Rates ◽

Cholesterol Monohydrate

Download Full-text

Composite alloy based on Co–Cr–Si–Zr–TiB2–BN system for nanostructured powders and functional coatings

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2019-98-2-50-56 ◽

2019 ◽

pp. 50-56

Author(s):

A. N. Skvortsova ◽

T. I. Bobkova ◽

B. V. Farmakovsky ◽

V. N. Klimov ◽

A. I. Dmitryuk

Keyword(s):

Corrosion Resistance ◽

Composite Alloy ◽

Functional Coatings ◽

Nanostructured Powder ◽

High Microhardness ◽

Nanostructured Powders

The paper studies the preparation of a composite nanostructured powder manufactured from an alloy of Co–Cr–Si–Zr–TiB2–BN system and describes functional coatings with high microhardness and corrosion resistance based on that powder.

Download Full-text

Nanostructured powders based on aluminum reinforced by silicon nitride designed for spraying of multifunctional strengthened coatings

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2019-97-1-65-73 ◽

2019 ◽

pp. 65-73

Author(s):

T. I. Bobkova ◽

B. V. Farmakovsky ◽

N. A. Sokolova

Keyword(s):

Silicon Nitride ◽

Composite Powder ◽

High Energy ◽

Cold Gas Dynamic Spraying ◽

Powder Materials ◽

Structure And Properties ◽

Gas Dynamic ◽

Composition Structure ◽

New Phase ◽

Nanostructured Powders

The work deals with topical issues such as development of composite nanostructured powder materials. The results of creating powders based on the system “aluminum–nitride of silicon” are presented. Complex investigations of the composition, structure and properties of powder materials, as well as coatings formed on their basis by supersonic cold gas dynamic spraying, were carried out. It has been found that the high-energy treatment of a powder mixture of aluminum with nanofibers of silicon nitride provides the formation of a composite powder in which a new phase of the Si(1-х)AlхO(1-х)Nх type is formed, which additionally increases the hardness in the coatings to be sprayed.

Download Full-text

Measurement of growth rates for single crystals and pressed tablets of CuSO4.5 H2O on a rotating disc

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19892951 ◽

1989 ◽

Vol 54 (11) ◽

pp. 2951-2961 ◽

Cited By ~ 2

Author(s):

Miloslav Karel ◽

Jaroslav Nývlt

Keyword(s):

Growth Rate ◽

Single Crystal ◽

Single Crystals ◽

Growth Rates ◽

Diffusion Coefficients ◽

Preferred Orientation ◽

Rotating Disc ◽

Dissolution Rates ◽

Rates Of Growth ◽

Good Agreement

Measured growth and dissolution rates of single crystals and tablets were used to calculate the overall linear rates of growth and dissolution of CuSO4.5 H2O crystals. The growth rate for the tablet is by 20% higher than that calculated for the single crystal. It has been concluded that this difference is due to a preferred orientation of crystal faces on the tablet surface. Calculated diffusion coefficients and thicknesses of the diffusion and hydrodynamic layers in the vicinity of the growing or dissolving crystal are in good agreement with published values.

Download Full-text

The reductive dissolution of synthetic goethite and hematite in dithionite

Clay Minerals ◽

10.1180/claymin.1987.022.3.07 ◽

1987 ◽

Vol 22 (3) ◽

pp. 329-337 ◽

Cited By ~ 83

Author(s):

J. Torrent ◽

U. Schwertmann ◽

V. Barron

Keyword(s):

Specific Surface ◽

Dissolution Rate ◽

Surface Area ◽

Reductive Dissolution ◽

Natural Environments ◽

Dissolution Rates ◽

Aluminium Substitution ◽

Initial Dissolution Rate

AbstractThe reductive dissolution by Na-dithionite of 28 synthetic goethites and 26 hematites having widely different crystal morphologies, specific surfaces and aluminium substitution levels has been investigated. For both minerals the initial dissolution rate per unit of surface area decreased with aluminium substitution. At similar aluminium substitution and specific surface, goethites and hematites showed similar dissolution rates. These results suggest that preferential, reductive dissolution of hematite in some natural environments, such as soils or sediments, might be due to the generally lower aluminium substitution of this mineral compared to goethite.

Download Full-text

Nanocrystal-Loaded Micelles for the Enhanced In Vivo Circulation of Docetaxel

Molecules ◽

10.3390/molecules26154481 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4481

Author(s):

Meng Cheng ◽

Qiaoming Liu ◽

Tiantian Gan ◽

Yuanying Fang ◽

Pengfei Yue ◽

...

Keyword(s):

Thin Film ◽

Retention Time ◽

Blood Circulation ◽

Crystalline State ◽

Circulation System ◽

Particle Sizes ◽

High Pressure Homogenization ◽

Rapid Dissolution ◽

Efficient Route

Prolonging in vivo circulation has proved to be an efficient route for enhancing the therapeutic effect of rapidly metabolized drugs. In this study, we aimed to construct a nanocrystal-loaded micelles delivery system to enhance the blood circulation of docetaxel (DOC). We employed high-pressure homogenization to prepare docetaxel nanocrystals (DOC(Nc)), and then produced docetaxel nanocrystal-loaded micelles (DOC(Nc)@mPEG-PLA) by a thin-film hydration method. The particle sizes of optimized DOC(Nc), docetaxel micelles (DOC@mPEG-PLA), and DOC(Nc)@mPEG-PLA were 168.4, 36.3, and 72.5 nm, respectively. The crystallinity of docetaxel was decreased after transforming it into nanocrystals, and the crystalline state of docetaxel in micelles was amorphous. The constructed DOC(Nc)@mPEG-PLA showed good stability as its particle size showed no significant change in 7 days. Despite their rapid dissolution, docetaxel nanocrystals exhibited higher bioavailability. The micelles prolonged the retention time of docetaxel in the circulation system of rats, and DOC(Nc)@mPEG-PLA exhibited the highest retention time and bioavailability. These results reveal that constructing nanocrystal-loaded micelles may be a promising way to enhance the in vivo circulation and bioavailability of rapidly metabolized drugs such as docetaxel.

Download Full-text

Metal-Assisted Catalytic Etching (MACE) for Nanofabrication of Semiconductor Powders

Micromachines ◽

10.3390/mi12070776 ◽

2021 ◽

Vol 12 (7) ◽

pp. 776

Author(s):

Kurt W. Kolasinski

Keyword(s):

Arbitrary Shape ◽

Metal Nanoparticle ◽

Metal Catalyst ◽

Spontaneous Deposition ◽

Electroless Etching ◽

Natural Tendency ◽

Galvanic Deposition ◽

Catalytic Etching ◽

Nanostructured Powders ◽

Shape And Size

Electroless etching of semiconductors has been elevated to an advanced micromachining process by the addition of a structured metal catalyst. Patterning of the catalyst by lithographic techniques facilitated the patterning of crystalline and polycrystalline wafer substrates. Galvanic deposition of metals on semiconductors has a natural tendency to produce nanoparticles rather than flat uniform films. This characteristic makes possible the etching of wafers and particles with arbitrary shape and size. While it has been widely recognized that spontaneous deposition of metal nanoparticles can be used in connection with etching to porosify wafers, it is also possible to produced nanostructured powders. Metal-assisted catalytic etching (MACE) can be controlled to produce (1) etch track pores with shapes and sizes closely related to the shape and size of the metal nanoparticle, (2) hierarchically porosified substrates exhibiting combinations of large etch track pores and mesopores, and (3) nanowires with either solid or mesoporous cores. This review discussed the mechanisms of porosification, processing advances, and the properties of the etch product with special emphasis on the etching of silicon powders.

Download Full-text