scholarly journals Model Analytical Development for Physical, Chemical, and Biological Characterization ofMomordica charantiaVegetable Drug

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Deysiane Oliveira Brandão ◽  
Geovani Pereira Guimarães ◽  
Ravely Lucena Santos ◽  
Fernando José de Lima Ramos Júnior ◽  
Karla Monik Alves da Silva ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Analytical Methods ◽  
Degradation Products ◽  
Particle Surface ◽  
Momordica Charantia ◽  
Raw Material ◽  
Gas Chromatography Mass Spectrometry ◽  
Semiarid Region ◽  
Particle Sizes ◽  
Particle Surface Area

Momordica charantiais a species cultivated throughout the world and widely used in folk medicine, and its medicinal benefits are well documented, especially its pharmacological properties, including antimicrobial activities. Analytical methods have been used to aid in the characterization of compounds derived from plant drug extracts and their products. This paper developed a methodological model to evaluate the integrity of the vegetable drugM. charantiain different particle sizes, using different analytical methods.M. charantiawas collected in the semiarid region of Paraíba, Brazil. The herbal medicine raw material derived from the leaves and fruits in different particle sizes was analyzed using thermoanalytical techniques as thermogravimetry (TG) and differential thermal analysis (DTA), pyrolysis coupled to gas chromatography/mass spectrometry (PYR-GC/MS), and nuclear magnetic resonance (1H NMR), in addition to the determination of antimicrobial activity. The different particle surface area among the samples was differentiated by the techniques. DTA and TG were used for assessing thermal and kinetic parameters and PYR-GC/MS was used for degradation products chromatographic identification through the pyrograms. The infusions obtained from the fruit and leaves ofMomordica charantiapresented antimicrobial activity.

scholarly journals Immersion Freezing of Kaolinite: Scaling with Particle Surface Area

2015 ◽  
Vol 73 (1) ◽  
pp. 263-278 ◽  
Author(s):  
Susan Hartmann ◽  
Heike Wex ◽  
Tina Clauss ◽  
Stefanie Augustin-Bauditz ◽  
Dennis Niedermeier ◽  
...  
Keyword(s):  
Surface Area ◽  
Particle Surface ◽  
Charged Particles ◽  
Particle Sizes ◽  
Angle Distribution ◽  
Particle Surface Area ◽  
Size Selection ◽  
Site Density ◽  
Multiply Charged ◽  
Immersion Freezing

Abstract This study presents an analysis showing that the freezing probability of kaolinite particles from Fluka scales exponentially with particle surface area for different atmospherically relevant particle sizes. Immersion freezing experiments were performed at the Leipzig Aerosol Cloud Interaction Simulator (LACIS). Size-selected kaolinite particles with mobility diameters of 300, 700, and 1000 nm were analyzed with one particle per droplet. First, it is demonstrated that immersion freezing is independent of the droplet volume. Using the mobility analyzer technique for size selection involves the presence of multiply charged particles in the quasi-monodisperse aerosol, which are larger than singly charged particles. The fractions of these were determined using cloud droplet activation measurements. The development of a multiple charge correction method has proven to be essential for deriving ice fractions and other quantities for measurements in which the here-applied method of size selection is used. When accounting for multiply charged particles (electric charge itself does not matter), both a time-independent and a time-dependent description of the freezing process can reproduce the measurements over the range of examined particle sizes. Hence, either a temperature-dependent surface site density or a single contact angle distribution was sufficient to parameterize the freezing behavior. From a comparison with earlier studies using kaolinite samples from the same provider, it is concluded that the neglect of multiply charged particles and, to a lesser extent, the effect of time can cause a significant overestimation of the ice nucleation site density of one order of magnitude, which translates into a temperature bias of 5–6 K.

scholarly journals Genomics Analysis and Degradation Characteristics of Lignin by Streptomyces Thermocarboxydus Strain DF3-3

2021 ◽  
Author(s):  
Fangyun Tan ◽  
Jun Cheng ◽  
Yu Zhang ◽  
Xingfu Jiang ◽  
Yueqiu Liu
Keyword(s):  
Energy Conversion ◽  
Manganese Peroxidase ◽  
Metabolic Pathways ◽  
Lignin Degradation ◽  
Degradation Products ◽  
Degradation Mechanism ◽  
Biomass Energy ◽  
Raw Material ◽  
Gas Chromatography Mass Spectrometry ◽  
Degradation Intermediates

Abstract Background: Lignocellulose is an important raw material for biomass-to-energy conversion, and it exhibits a complex but inefficient degradation mechanism. Microbial degradation is promising due to its environmental adaptability and biochemical versatility, but the pathways used by microbes for lignin degradation have not been fully studied. Degradation intermediates and complex metabolic pathways require more study.Results: A novel actinomycete DF3-3, with the potential for lignin degradation, was screened and isolated. After morphological and molecular identification, DF3-3 was determined to be Streptomyces thermocarboxydus. The degradation of alkali lignin reached 31% within 15 days. Manganese peroxidase and laccase demonstrated their greatest activity levels, 1821.66 UL-1 and 1265.58 UL-1, respectively, on the sixth day. The highest lignin peroxidase activity was 480.33 UL-1 on the fourth day. A total of 19 lignin degradation intermediates were identified by gas chromatography-mass spectrometry (GC-MS), including 10 aromatic compounds. Genome sequencing and annotation identified 107 lignin-degrading enzyme-coding genes containing three core enzymatic systems for lignin depolymerization: laccases, peroxidases and manganese peroxidase. In total, 7 lignin metabolic pathways were predicted.Conclusions: Streptomyces thermocarboxydus strain DF3-3 has good lignin degradation ability. Degradation products and genomics analyses of DF3-3 show that it has a relatively complete lignin degradation pathway, including the β-ketoadipate pathway and peripheral reactions; gentisate pathway; anthranilate pathway; homogentisic pathway; and catabolic pathway for resorcinol. Two other pathways, the phenylacetate-CoA pathway and the 2,3-dihydroxyphenylpropionic acid pathway, are predicted based on genome data alone. This study provides the basis for future characterization of potential biotransformation enzyme systems for biomass energy conversion.

scholarly journals The Effect of Temperature and Particle Size on the Pyrolysis Products of Waste Tires and the Formation Mechanism of Limonene

2021 ◽  
Vol 72 (3) ◽  
pp. 45-57
Author(s):  
Lei Gong ◽  
Jin Wang ◽  
Hong Wei Yu ◽  
Ying Zhou ◽  
Tong Zou ◽  
...  
Keyword(s):  
Particle Size ◽  
Pyrolysis Temperature ◽  
Rapid Development ◽  
Pyrolysis Product ◽  
Raw Material ◽  
Effect Of Temperature ◽  
Gas Chromatography Mass Spectrometry ◽  
Particle Sizes ◽  
Pyrolysis Products ◽  
Waste Tires

The rapid development of the automotive industry has led to the accumulation of a large number of waste tires that contain a lot of reusable energy. Macromolecular organics in waste tires can be crack small molecule organics via pyrolysis. In this experiment, thermogravimetry (TG) and pyrolizer-gas chromatography/mass spectrometry (PY-GC/MS) were used to study the pyrolysis behavior of waste tires with different particle sizes, and the effect of temperature and particle size on the pyrolysis products of waste tires under low-temperature pyrolysis conditions, respectively. The volatile substances in waste tires decomposed intensively at 300-500�C and were completely pyrolyzed at 500�C. The content of limonene in the pyrolysis product was significant, and the yield of limonene could reach 27.73% when the waste tire particles were 0.180-0.250 mm and the pyrolysis temperature was 380�C. The mechanism of limonene formation from waste tires was discussed. This study indicated that raw material particle sizes and pyrolysis temperature could change the components and content of pyrolysis products.

Antimicrobial activity of Eurycoma longifolia and Momordica charantia

Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
R Łos ◽  
K Skalicka-Wozniak ◽  
J Widelski ◽  
A Malm ◽  
K Głowniak
Keyword(s):  
Antimicrobial Activity ◽  
Momordica Charantia ◽  
Eurycoma Longifolia

Quantities Directly Measurable by Scattering

2018 ◽  
Author(s):  
Eaton E. Lattman ◽  
Thomas D. Grant ◽  
Edward H. Snell
Keyword(s):  
Molecular Weight ◽  
Particle Shape ◽  
Particle Surface ◽  
Scattering Data ◽  
Radius Of Gyration ◽  
Particle Volume ◽  
Particle Surface Area ◽  
Scattering Angle ◽  
Particle Dimension ◽  
Maximum Particle

In this chapter we note that solution scattering data can be divided into four regions. At zero scattering angle, the scattering provides information on molecular weight of the particle in solution. Beyond that, the scattering is influenced by the radius of gyration. As the scattering angle increases, the scattering is influenced by the particle shape, and finally by the interface with the particle and the solution. There are a number of important invariants that can be calculated directly from the data including molecular mass, radius of gyration, Porod invariant, particle volume, maximum particle dimension, particle surface area, correlation length, and volume of correlation. The meaning of these is described in turn along with their mathematical derivations.

Influence of particle surface area on the toxicity of insoluble manganese dioxide dusts

1997 ◽  
Vol 71 (12) ◽  
pp. 725-729 ◽  
Author(s):  
Dominique Lison ◽  
Cécile Lardot ◽  
François Huaux ◽  
Giovanna Zanetti ◽  
Bice Fubini
Keyword(s):  
Manganese Dioxide ◽  
Surface Area ◽  
Particle Surface ◽  
Particle Surface Area

scholarly journals Ice nucleation abilities of soot particles determined with the Horizontal Ice Nucleation Chamber

2018 ◽  
Vol 18 (18) ◽  
pp. 13363-13392 ◽  
Author(s):  
Fabian Mahrt ◽  
Claudia Marcolli ◽  
Robert O. David ◽  
Philippe Grönquist ◽  
Eszter J. Barthazy Meier ◽  
...  
Keyword(s):  
Particle Size ◽  
Water Saturation ◽  
Particle Surface ◽  
Water Vapor Sorption ◽  
Contact Angles ◽  
Ice Nucleation ◽  
Particle Surface Area ◽  
Soot Particles ◽  
Microphysical Properties ◽  
Homogeneous Freezing

Abstract. Ice nucleation by different types of soot particles is systematically investigated over the temperature range from 218 to 253 K relevant for both mixed-phase (MPCs) and cirrus clouds. Soot types were selected to represent a range of physicochemical properties associated with combustion particles. Their ice nucleation ability was determined as a function of particle size using relative humidity (RH) scans in the Horizontal Ice Nucleation Chamber (HINC). We complement our ice nucleation results by a suite of particle characterization measurements, including determination of particle surface area, fractal dimension, temperature-dependent mass loss (ML), water vapor sorption and inferred porosity measurements. Independent of particle size, all soot types reveal absence of ice nucleation below and at water saturation in the MPC regime (T>235 K). In the cirrus regime (T≤235 K), soot types show different freezing behavior depending on particle size and soot type, but the freezing is closely linked to the soot particle properties. Specifically, our results suggest that if soot aggregates contain mesopores (pore diameters of 2–50 nm) and have sufficiently low water–soot contact angles, they show ice nucleation activity and can contribute to ice formation in the cirrus regime at RH well below homogeneous freezing of solution droplets. We attribute the observed ice nucleation to a pore condensation and freezing (PCF) mechanism. Nevertheless, soot particles without cavities of the right size and/or too-high contact angles nucleate ice only at or well above the RH required for homogeneous freezing conditions of solution droplets. Thus, our results imply that soot particles able to nucleate ice via PCF could impact the microphysical properties of ice clouds.

scholarly journals Effect of Home Grinding on Properties of Brewed Coffee

2014 ◽  
Vol 4 (1) ◽  
pp. 77
Author(s):  
Christopher Murray ◽  
Thamara Laredo
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Distribution Density ◽  
Particle Surface ◽  
Particle Surface Area ◽  
Present Evidence ◽  
Caffeine Content ◽  
General Recommendation ◽  
Grinding Time ◽  
Ground Coffee

<p>We present measurements of particle size distribution, density, loss of coffee on brewing and caffeine content in brewed coffee (as measured using Fourier Transform Infrared Spectroscopy) as a function of grinding time using a blade-type grinder. In general, there is not a lack of correlation between coffee properties and grinding for grinding times in excess of 42 s, but mass loss on brewing and caffeine content are both increased with grinding times between 0 and 42 s. In addition, we present evidence that this dependence of the composition of brewed coffee on grinding time is a function of increased coffee particle surface area that results from grinding, rather than increased loss of grounds into the brewed beverage or increased percolation time. Finally, we present a general recommendation for determining equivalency between small amounts of finely ground coffee and larger amounts of coarser-ground coffee.</p>

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