scholarly journals Continuous Flow Synthesis of ZIF-8 Biocomposites with Tuneable Particle Size

2020 ◽  
Author(s):  
Francesco Carraro ◽  
Jason D. Williams ◽  
Mercedes Linares-Moreau ◽  
chiara parise ◽  
Weibin Liang ◽  
...  
Keyword(s):  
Particle Size ◽  
Continuous Flow ◽  
Continuous Production ◽  
Particle Growth ◽  
Research Area ◽  
Zeolitic Imidazolate Framework ◽  
Model Protein ◽  
Kinetics Of ◽  
Specific Particle

Zeolitic Imidazolate Framework (ZIF) biocomposites show the capacity to protect and deliver bio-therapeutics. To date, the progress in this research area is based on laboratory batch methods. To further explore the potential of ZIF-biocomposites for application to biomedicine and biotechnology, the continuous production of ZIF-biocomposites of specific particle size is desirable. We report the first continuous flow synthetic method for the encapsulation of a model protein (BSA) and a clinical therapeutic (α1-antitrypsin, AAT) in ZIF-8. We studied the in situ kinetics of nucleation, growth and crystallization of BSA-ZIF-8 by SAXS. By controlling the injection time of ethanol, we could quench the particle growth via ethanol-induced crystallization. The particle size of the biocomposite was tuned in the 40-100 nm range by varying residence time prior to introduction of ethanol.<br>

Continuous Flow Synthesis of ZIF-8 Biocomposites with Tuneable Particle Size

2020 ◽  
Author(s):  
Francesco Carraro ◽  
Jason D. Williams ◽  
Mercedes Linares-Moreau ◽  
chiara parise ◽  
Weibin Liang ◽  
...  
Keyword(s):  
Particle Size ◽  
Continuous Flow ◽  
Continuous Production ◽  
Particle Growth ◽  
Research Area ◽  
Zeolitic Imidazolate Framework ◽  
Model Protein ◽  
Kinetics Of ◽  
Specific Particle

Zeolitic Imidazolate Framework (ZIF) biocomposites show the capacity to protect and deliver bio-therapeutics. To date, the progress in this research area is based on laboratory batch methods. To further explore the potential of ZIF-biocomposites for application to biomedicine and biotechnology, the continuous production of ZIF-biocomposites of specific particle size is desirable. We report the first continuous flow synthetic method for the encapsulation of a model protein (BSA) and a clinical therapeutic (α1-antitrypsin, AAT) in ZIF-8. We studied the in situ kinetics of nucleation, growth and crystallization of BSA-ZIF-8 by SAXS. By controlling the injection time of ethanol, we could quench the particle growth via ethanol-induced crystallization. The particle size of the biocomposite was tuned in the 40-100 nm range by varying residence time prior to introduction of ethanol.<br>

Physically effectiveness of beet pulp in dairy cows 1: physical characteristics, ruminal kinetics of nutrients degradation, hydration, and functional specific gravity

2007 ◽  
Vol 2007 ◽  
pp. 215-215
Author(s):  
Teimouri Yansari Asadollah
Keyword(s):  
Particle Size ◽  
Specific Gravity ◽  
Physical Characteristics ◽  
Particle Size Measurement ◽  
Effective Factor ◽  
Beet Pulp ◽  
Water Holding ◽  
Kinetics Of

Some physical properties including particle size, functional specific gravity (FSG; Teimouri Yansari et al., 2004), hydration rate, water holding capacity (WHC) and ionion-cation exchange (Van Soest, 1994) influenced on physically effective factor (pef), but only particle size measurement is central to all effective fibre systems. The objective of this study was to evaluate the effects of three types of beet pulp (BP) on physical characteristics including bulk density, particle size, kinetics of hydration, FSG, WHC, and intrinsic osmotic pressure that measured usingin vitroandin situmethods.

scholarly journals Effect of Synthesis Temperature on the Crystallization and Growth of In Situ Prepared Nanohydroxyapatite in Chitosan Matrix

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Habiba Elhendawi ◽  
R. M. Felfel ◽  
Bothaina M. Abd El-Hady ◽  
Fikry M. Reicha
Keyword(s):  
Particle Size ◽  
Biomedical Applications ◽  
Particle Growth ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Processing Temperature ◽  
Hydroxyapatite Nanoparticles ◽  
Chitosan Matrix ◽  
Coprecipitation Technique

Hydroxyapatite nanoparticles (nHA) have been used in different biomedical applications where certain particle size distribution and morphology are required. Chitosan/hydroxyapatite (CS/HA) nanocomposites were prepared using in situ coprecipitation technique and the effect of the reaction temperature on the crystallization and particle growth of the prepared nanohydroxyapatite particles was investigated. The composites were prepared at different synthesis temperatures (−10, 37, and 60°C). XRD, FTIR, thermal analysis, TEM and SEM techniques were used to characterize the prepared specimens. It was found that the increase in processing temperature had a great affect on particle size and crystal structure of nHA. The low temperature (−10°C) showed inhabitation of the HA growth in c-direction and low crystallinity which was confirmed using XRD and electron diffraction pattern of TEM. Molar ratio of the bone-like apatite layer (Ca/P) for the nanocomposite prepared at 60°C was higher was higher than the composites prepared at lower temperatures (37 and −10°C).

scholarly journals Effects of lucerne particle size and source of dietary carbohydrates on in situ degradation and ruminal variables in sheep

2009 ◽  
Vol 54 (No. 6) ◽  
pp. 277-285 ◽  
Author(s):  
A. Asadi Alamouti ◽  
G.R. Ghorbani ◽  
M. Alikhani ◽  
H.R. Rahmani ◽  
A. Teimouri Yansari ◽  
...  
Keyword(s):  
Particle Size ◽  
Latin Square ◽  
Dietary Carbohydrates ◽  
Ruminal Fermentation ◽  
Ruminal Ph ◽  
Degradation Rate Constant ◽  
Beet Pulp ◽  
Feeding Diets ◽  
Kinetics Of

The effects of altering forage particle size and source of rapidly degradable carbohydrates on <I>in situ</I> degradation and ruminal variables were studied in four Iranian male sheep. The study was designed as a Latin square with a 2 × 2 factorial arrangement of treatments including two carbohydrate sources (pelleted beet pulp vs. maize- and barley-based concentrate) and two lucerne particle sizes (2.38 vs. 0.94 mm). Kinetics of disappearance of lucerne, concentrates and mixed samples was studied <I>in situ</I>. Among feed samples, the degradation rate constant of lucerne dry matter was higher (<I>P</I> < 0.02) and disappearance of lucerne neutral detergent fibre (NDF) in 4 h of incubation was lower (<I>P</I> = 0.06) in diets with reduced particle size. The rapidly degradable fraction of lucerne samples was also affected by treatments. Other degradability components were not affected. The mean ruminal pH was lower in diets containing short hay than in those containing long hay (5.76 vs. 5.86, <I>P</I> < 0.006) and pH values were consistently lower immediately after feeding diets with short lucerne hay. The form of carbohydrates did not affect ruminal pH, however, altering the source of carbohydrates changed the pattern of pH over time. Total volatile fatty acid (VFA) concentration and proportions of individual VFA were similar but numerical differences indicated a lower acetate to propionate ratio in diets with short hay. Most of the affected variables were influenced by the particle size of forage to a larger extent than by the source of rapidly degradable carbohydrates or the interaction between them. So, when sheep diets contain no more than 250 g/kg starch, the source of dietary carbohydrates may not interact with forage particle size to affect DM degradability and ruminal fermentation.

scholarly journals Model simulations of the chemical and aerosol microphysical evolution of the Sarychev Peak 2009 eruption cloud compared to in-situ and satellite observations

2017 ◽  
Author(s):  
Thibaut Lurton ◽  
Fabrice Jégou ◽  
Gwenaël Berthet ◽  
Jean-Baptiste Renard ◽  
Lieven Clarisse ◽  
...  
Keyword(s):  
Particle Size ◽  
Stratospheric Ozone ◽  
Volcanic Eruptions ◽  
Particle Growth ◽  
Climate Impact ◽  
Stratospheric Aerosol ◽  
Stratospheric Chemistry ◽  
The Impact ◽  
Sarychev Peak

Abstract. Volcanic eruptions impact climate through the injection of sulfur dioxide (SO2), which is oxidized to form sulfuric acid aerosol particles that can enhance the stratospheric aerosol optical depth (SAOD). Besides large-magnitude eruptions, moderate-magnitude eruptions such as Kasatochi in 2008 and Sarychev Peak in 2009 can have a significant impact on stratospheric aerosol and hence climate. However, uncertainties remain in quantifying the atmospheric and climatic impacts of the 2009 Sarychev Peak eruption due to limitations in previous model representations of volcanic aerosol microphysics and particle size, whilst biases have been identified in satellite estimates of post-eruption SAOD. In addition, the 2009 Sarychev Peak eruption co-injected hydrogen chloride (HCl) alongside SO2, whose potential stratospheric chemistry impacts have not been investigated to date. We present a study of the stratospheric SO2-particle-HCl processing and impacts following Sarychev Peak eruption, using the CESM1(WACCM)-CARMA sectional aerosol microphysics model (with no a priori assumption on particle size). The Sarychev Peak 2009 eruption injected 0.9 Tg of SO2 into the upper troposphere and lower stratosphere (UTLS), enhancing the aerosol load in the Northern hemisphere. The post-eruption evolution of the volcanic SO2 in space and time are well reproduced by the model when compared to IASI (Infrared Atmospheric Sounding Interferometer) satellite data. Co-injection of 27 Gg HCl causes a lengthening of the SO2 lifetime and a slight delay in the formation of aerosols, and acts to enhance the destruction of stratospheric ozone and mono-nitrogen oxides (NOx) compared to the simulation with volcanic SO2 only. We therefore highlight the need to account for volcanic halogen chemistry when simulating the impact of eruptions such as Sarychev on stratospheric chemistry. The model-simulated evolution of effective radius (reff), reflects new particle formation followed by particle growth that enhances reff to reach up to 0.2 µm on zonal average. Comparisons of the model-simulated particle number and size-distributions to balloon-borne in-situ stratospheric observations over Kiruna, Sweden, in August and September 2009, and over Laramie, U.S.A., in June and November 2009 show good agreement and quantitatively confirms the post-eruption particle enhancement. We show that the model-simulated SAOD is consistent with that derived from OSIRIS (Optical Spectrograph and InfraRed Imager System) when both the saturation bias of OSIRIS and the fact that extinction profiles may terminate well above the tropopause are taken into account. Previous modelling studies (involving assumptions on particle size) that reported agreement to (biased) post-eruption estimates of SAOD derived from OSIRIS likely underestimated the climate impact of the 2009 Sarychev Peak eruption.

Effect of Temperature and Vapor-phase Encapsulation on Particle Growth and Morphology

1999 ◽  
Vol 14 (4) ◽  
pp. 1664-1671 ◽  
Author(s):  
Sheryl H. Ehrman ◽  
Maria I. Aquino-Class ◽  
Michael R. Zachariah
Keyword(s):  
Particle Size ◽  
Vapor Phase ◽  
Particle Growth ◽  
Effect Of Temperature ◽  
Transmission Electron Micrograph ◽  
Transmission Electron ◽  
Size And Morphology ◽  
Silicon And Germanium ◽  
Increasing Temperature

The effect of in situ vapor phase salt-encapsulation on particle size and morphology was systematically investigated in a sodium co-flow/furnace reactor. The temperature of the furnace was varied, and the primary particle size and degree of agglomeration of the resulting silicon and germanium particles were determined from transmission electron micrograph images of particles sampled in situ. Particle size increased with increasing temperature, a trend expected from our understanding of particle formation in a high-temperature process in the absence of an encapsulant. Germanium, which coalesces faster than silicon, formed larger particles than silicon at the same temperatures, also in agreement with observations of particle growth in more traditional aerosol processes. At the highest temperatures, unagglomerated particles were formed, while at low temperatures, agglomerated particles were formed, with agglomerate shape following the shape of the salt coating.

scholarly journals Growth kinetics of metal nanoparticles on solid surfaces

2014 ◽  
Vol 70 (a1) ◽  
pp. C1176-C1176
Author(s):  
Ezzeldin Metwalli
Keyword(s):  
Block Copolymer ◽  
Metal Nanoparticles ◽  
Growth Kinetics ◽  
Particle Growth ◽  
Polymer Surfaces ◽  
Particle Mobility ◽  
Metal Interactions ◽  
Metal Metal ◽  
Kinetics Of

Dispersed metal nanoparticles (nps) in a polymer matrix are essential for many technological applications, including biological imaging, thin film technology, magnetic recording media, optoelectronics and sensors. Real time investigation of the evolution of nps size and shape during the in-situ metal deposition on polymer thin films enables a fine tune of magnetic and electric properties. Metals in their atomic state are deposited on several homopolymer and block copolymer films by DC magnetron system (Metwalli et al., 2013, Metwalli et al., 2008, Buffet et al., 2011). With the unprecedented time resolution of 10 milliseconds, the growth kinetics of the metal nps on the polymer surfaces is monitored using in-situ GISAXS. An exponential growth of nps size on all polymer surfaces is observed. Below a certain critical nps size, an initial fast particle growth is due to high particle mobility. A slower kinetics at concentrated metal dispersion is due to the strong metal-metal interactions. The metal growth kinetics study for many chemically different homopolymer films explains the long-time debated high selectivity characteristics of metals towards one block in block copolymer based nano-templates.

Sign in / Sign up

Export Citation Format

Share Document