scholarly journals Effects of Aerosol Size and Coating Thickness on the Molecular Detection using Extractive Electrospray Ionization

2021 ◽  
Author(s):  
Chuan Ping Lee ◽  
Mihnea Surdu ◽  
David M. Bell ◽  
Houssni Lamkaddam ◽  
Mingyi Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Electrospray Ionization ◽  
Coating Thickness ◽  
Size Dependence ◽  
Reaction Products ◽  
Aerosol Formation ◽  
Extraction Mechanism ◽  
Probe Size

Abstract. Extractive electrospray ionization (EESI) is a well-known technique for high throughput online molecular characterization of chemical reaction products and intermediates, detection of native biomolecules, in vivo metabolomics, and environmental monitoring with negligible thermal and ionization-induced fragmentation for over two decades. However, the EESI extraction mechanism remains uncertain. Prior studies disagree whether analyte particles between 20 and 400 nm diameter are fully extracted or if the extraction is limited to the surface layer. Here, we examined the analyte extraction mechanism by assessing the influence of analyte particle size and coating thickness on the detection of the molecules therein. We find that analyte particles are extracted fully: Organics-coated NH4NO3 particles with a fixed core volume (156 and 226 nm in diameter without coating) show constant signals for NH4NO3 independent of the shell coating thickness, while the signals of the secondary organic molecules comprising the shell varied proportionally to the shell volume. We also find that the EESI sensitivity exhibits a strong size dependence, with an increase in sensitivity by one to three orders of magnitude as analyte particle size decreases from 300 nm to 30 nm. This dependence varies with the electrospray (ES) droplet size and the analyte particle residence time in the EESI inlet, suggesting that the EESI sensitivity is influenced by the coagulation rates between analyte particles and ES droplets. Overall, our results indicate that, in the EESI, analyte particles are fully extracted by the ES droplets regardless of the chemical composition, when they are collected by the ES droplets. However, their coalescence is not complete and depends strongly on their size. This size-dependence is especially relevant when EESI is used to probe size-varying analyte particles as is the case in aerosol formation and growth studies with size ranges below 100 nm, while it does not significantly influence the detection of ambient aerosol dominated by particle sizes ranging between 100–2500 nm, i.e. the accumulation mode.

scholarly journals Effects of aerosol size and coating thickness on the molecular detection using extractive electrospray ionization

2021 ◽  
Vol 14 (9) ◽  
pp. 5913-5923
Author(s):  
Chuan Ping Lee ◽  
Mihnea Surdu ◽  
David M. Bell ◽  
Houssni Lamkaddam ◽  
Mingyi Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Electrospray Ionization ◽  
Coating Thickness ◽  
Size Dependence ◽  
Reaction Products ◽  
Aerosol Formation ◽  
Extraction Mechanism ◽  
Probe Size

Abstract. Extractive electrospray ionization (EESI) has been a well-known technique for high-throughput online molecular characterization of chemical reaction products and intermediates, detection of native biomolecules, in vivo metabolomics, and environmental monitoring with negligible thermal and ionization-induced fragmentation for over two decades. However, the EESI extraction mechanism remains uncertain. Prior studies disagree on whether particles between 20 and 400 nm diameter are fully extracted or if the extraction is limited to the surface layer. Here, we examined the analyte extraction mechanism by assessing the influence of particle size and coating thickness on the detection of the molecules therein. We find that particles are extracted fully: organics-coated NH4NO3 particles with a fixed core volume (156 and 226 nm in diameter without coating) showed constant EESI signals for NH4NO3 independent of the shell coating thickness, while the signals of the secondary organic molecules comprising the shell varied proportionally to the shell volume. We also found that the EESI sensitivity exhibited a strong size dependence, with an increase in sensitivity by 1–3 orders of magnitude as particle size decreased from 300 to 30 nm. This dependence varied with the electrospray (ES) droplet size, the particle size and the residence time for coagulation in the EESI inlet, suggesting that the EESI sensitivity was influenced by the coagulation coefficient between particles and ES droplets. Overall, our results indicate that, in the EESI, particles are fully extracted by the ES droplets regardless of the chemical composition, when they are collected by the ES droplets. However, their coalescence is not complete and depends strongly on their size. This size dependence is especially relevant when EESI is used to probe size-varying particles as is the case in aerosol formation and growth studies with size ranges below 100 nm.

Casuarina equisetifoliaExtract Loaded Phytosomes: Optimization, Characterization andIn vivoEvaluation of Antidiabetic and Antihyperlipidemic Activities in Wistar Rats

2019 ◽  
Vol 9 (2) ◽  
pp. 116-133 ◽  
Author(s):  
Anjana Rani ◽  
Sunil Kumar ◽  
Roop K. Khar
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Therapeutic Efficacy ◽  
Entrapment Efficiency ◽  
Herbal Extract ◽  
Casuarina Equisetifolia ◽  
Novel Drug

Background:Herbal extracts have brilliant in-vitro activity but less in-vivo action in light of their macromolecular size and poor lipid solubility bringing about poor absorption and low bioavailability. These issues can be corrected by designing novel drug delivery systems. Phytosomes provide better absorption and bioavailability when compared to conventional herbal extract.Objective:This paper deals with the preparation, optimization and characterization of Phytosome of plant extract and in vivo assessment of antidiabetic and antihyperlipidemic activity for improved therapeutic efficacy having sufficient stability.Methods:Preliminary distinctive strategies were utilized to get ready Phytosome and antisolvent precipitation method was chosen. The formulation was guided by a full factorial design to study the effect of Independent variable on various dependent variables and resulted in an optimised product. Response contour plots were generated for each response factor to predict a phytosomal composition that yields phytosome formulation having least particle size and maximum entrapment efficiency.Results:Mean particle size, entrapment efficiency and Span value were found to be 295 ± 0.53nm, 82.43 ± 1.65% and 0.34 ± 0.14 respectively. Zeta potential was found to be 19.35mv, indicating the formation of stable formulation. In vitro release study described that the drug release follows the Korsmeyer- Peppas kinetic model. The results proved that Phytosomes of Casuarina equisetifolia extract exhibited more antidiabetic potential and antihyperlipidemic properties as compared to crude Casuarina extract.Conclusion:Phytosomes of Casuarina equestifolia extract was successfully formulated having good entrapment efficiency and physico-chemical characterization of the optimized product, confirming the formation of stable formulation. In vivo antidiabetic activity confirmed better potential of the optimised formulation. Consequently, it has been presumed that Phytosomes of Casuarina equisetifolia extract serve as a useful novel drug delivery system and provide more therapeutic efficacy than conventional plant extracts.

scholarly journals Design, Preparation, and Characterization of Dioscin Nanosuspensions and Evaluation of Their Protective Effect against Carbon Tetrachloride-Induced Acute Liver Injury in Mice

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Hong-Ye JU ◽  
Kun-Xia Hu ◽  
Guo-Wang Zhao ◽  
Zhi-Shu Tang ◽  
Xiao Song
Keyword(s):  
Particle Size ◽  
Protective Effect ◽  
Soybean Lecithin ◽  
Chemical Properties ◽  
Spherical Shape ◽  
Positive Control ◽  
The Body

The purpose of this study was to prepare a dioscin nanosuspension (Dio-NS) that has a better distance and high solubility for oral administration and to evaluate its hepatoprotective effects. Optimal primary manufacture parameters, including shear time, shear speed, emulation temperature, pressure, and cycles of homogenization, were determined by single-factor experiments. The concentrations of dioscin, SDS, and soybean lecithin were optimized using the central composite design-response surface method, and their effects on the mean particle size (MPS) and particle size distribution of Dio-NS were investigated. Characterization of the Dio-NS formulations included examinations of the surface morphology and physical status of dioscin in Dio-NS, the stability of Dio-NS at different temperatures, in vitro solubility, and liver protective effect in vivo. Under optimal conditions, Dio-NS had an MPS of 106.72 nm, polydispersity index of 0.221, and zeta potential of −34.27 mV. Furthermore, the proportion of dioscin in Dio-NS was approximately 21.26%. The observation of particles with a spherical shape and the disappearance of crystalline peaks indicated that the physical and chemical properties of Dio-NS were altered. Furthermore, we observed that the dissolution of Dio-NS was superior to that of a physical mixture and Dio-GZF. Moreover, Dio-NS was demonstrated to have a protective effect against CCl4-induced acute liver damage in mice that was equivalent to that of silymarin (a positive control drug) at the same dose. The good hepatoprotective effect of our Dio-NS preparation can provide a theoretical basis for investigating its absorption mechanisms in the body.

scholarly journals Synthesis and Characterization of Herbal Nano-suspensions and Evaluation of their In-vivo Antihypertensive Potential with Especial Focus on Piperine

2020 ◽  
pp. 202-215
Author(s):  
Arifa Murtaza ◽  
Tayyba Rehman ◽  
Zohaib Zafar ◽  
Safia Noreen ◽  
Mahwish Iqbal ◽  
...  
Keyword(s):  
Particle Size ◽  
Scientific Community ◽  
Biological Activities ◽  
Aqueous Solubility ◽  
Water Soluble ◽  
Piper Nigrum ◽  
Synthesis And Characterization ◽  
Poorly Water Soluble

Poor aqueous solubility is the principle obstacle in accomplishing suitable oral bioavailability for huge proportion of drug composites in drug development todays. Nano-suspension is an emerging field of research in the scientific community to provide a new solution for poorly water-soluble active constituents. The objective of the nano-suspension is to reduce the drug particle size (100-200 nm) range, which enhance solubility and bioavailability of biopharmaceutical active compounds. Crude extract of Piper nigrum shows various biological activities but poor aqueous solubility so, there is a need to isolate the piperine from Piper nigrum and prepare its nano-suspension to reduce particle size and enhance its bioavailability. This review defines the principles behind nanosizing, the synthesis and characterization of piperine nano-suspension as well as the recent practice withapplication of such formulations in-vivo can be used as a better alternative to treat cardiovascular diseases with improved therapeutic efficacy compared to extract.

scholarly journals Enzymes in context: Kinetic characterization of enzymes for systems biology

2005 ◽  
Vol 27 (2) ◽  
pp. 11-14 ◽  
Author(s):  
Athel Cornish-Bowden ◽  
Jan-Hendrik S. Hofmeyr
Keyword(s):  
Small Molecules ◽  
Living Organism ◽  
The Other ◽  
Rate Equations ◽  
Reaction Products ◽  
Care Needs ◽  
Physiological Conditions ◽  
Cooperative Kinetics

The kinetic behaviour of enzymes is typically observed in conditions appropriate for studying questions of mechanism of action, but these are not necessarily the most appropriate for studying their physiological roles, because they are often too far from those that exist in the living organism. Enzymes therefore need to be studied with natural substrates in the presence of all of the other small molecules likely to affect the activity in vivo, including the reaction products, so that the reverse reaction is not artificially prohibited. As complete reversible rate equations are often unmanageably complicated, especially for cooperative kinetics, care needs to be taken in choosing simpler equations that preserve the properties that are relevant in physiological conditions.

TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

1988 ◽  
Vol 46 ◽  
pp. 738-739
Author(s):  
G. Das ◽  
R. E. Omlor
Keyword(s):  
Titanium Alloys ◽  
Reaction Zone ◽  
Carbon Layer ◽  
Fiber Reinforced ◽  
Reaction Products ◽  
Sic Fibers ◽  
Sic Fiber ◽  
The Matrix ◽  
Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

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