scholarly journals Uptake and toxicity of polystyrene micro/nanoplastics in gastric cells: Effects of particle size and surface functionalization

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260803
Author(s):  
Amrita Banerjee ◽  
Lloyd O. Billey ◽  
Weilin L. Shelver
Keyword(s):  
Particle Size ◽  
Surface Functionalization ◽  
Exposure Period ◽  
Particle Sizes ◽  
High Toxicity ◽  
Aquatic Life ◽  
Terrestrial Species ◽  
Gastric Cells ◽  
Functionalized Particles

Toxicity of micro or nanoplastics (MP/NP) in aquatic life is well-documented, however, information about the consequences of exposure to these particles in terrestrial species is scarce. This study was used to evaluate the uptake and/or toxicity of polystyrene MP/NP in human gastric cells, comparing doses, particle sizes (50, 100, 200, 500, 1000 or 5000 nm) and surface functionalization (aminated, carboxylated or non-functionalized). In general, the uptake of 50 nm particles was significantly higher than 1000 nm particles. Among the 50 nm particles, the aminated particles were more avidly taken up by the cells and were cytotoxic at a lower concentration (≥ 7.5 μg/mL) compared to same sized carboxylated or non-functionalized particles (≥ 50 μg/mL). High toxicity of 50 nm aminated particles corresponded well with significantly high rates of apoptosis-necrosis induced by these particles in 4 h (29.2% of total cells) compared to all other particles (≤ 16.8%). The trend of apoptosis-necrosis induction by aminated particles in 4 h was 50 > 5000 > 1000 > 500 > 200 > 100 nm. The 50 nm carboxylated or non-functionalized particles also induced higher levels of apoptosis-necrosis in the cells compared to 100, 1000 and 5000 nm particles with same surface functionalization but longer exposure (24 h) to 50 nm carboxylated or non-functionalized particles significantly (p<0.0001) increased apoptosis-necrosis in the cells. The study demonstrated that the toxicity of MP/NP to gastric cells was dependent on particle size, dose surface functionalization and exposure period.

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

scholarly journals Effect of particle size on phytochemical composition and antioxidant properties of Sargassum cristaefolium ethanol extract

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. S. Prasedya ◽  
A. Frediansyah ◽  
N. W. R. Martyasari ◽  
B. K. Ilhami ◽  
A. S. Abidin ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Particle Size ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Ethanol Extract ◽  
Total Phenolic ◽  
Particle Sizes ◽  
Epicatechin Gallate ◽  
Particle Size Reduction ◽  
Phytochemical Composition

AbstractSample particle size is an important parameter in the solid–liquid extraction system of natural products for obtaining their bioactive compounds. This study evaluates the effect of sample particle size on the phytochemical composition and antioxidant activity of brown macroalgae Sargassum cristaefolium. The crude ethanol extract was extracted from dried powders of S.cristeafolium with various particle sizes (> 4000 µm, > 250 µm, > 125 µm, > 45 µm, and < 45 µm). The ethanolic extracts of S.cristaefolium were analysed for Total Phenolic Content (TPC), Total Flavonoid Content (TFC), phenolic compound concentration and antioxidant activities. The extract yield and phytochemical composition were more abundant in smaller particle sizes. Furthermore, the TPC (14.19 ± 2.08 mg GAE/g extract to 43.27 ± 2.56 mg GAE/g extract) and TFC (9.6 ± 1.8 mg QE/g extract to 70.27 ± 3.59 mg QE/g extract) values also significantly increased as particle sizes decreased. In addition, phenolic compounds epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), and Epigallocatechin gallate (EGCG) concentration were frequently increased in samples of smaller particle sizes based on two-way ANOVA and Tukey’s multiple comparison analysis. These results correlate with the significantly stronger antioxidant activity in samples with smaller particle sizes. The smallest particle size (< 45 µm) demonstrated the strongest antioxidant activity based on DPPH, ABTS, hydroxyl assay and FRAP. In addition, ramp function graph evaluates the desired particle size for maximum phytochemical composition and antioxidant activity is 44 µm. In conclusion, current results show the importance of particle size reduction of macroalgae samples to increase the effectivity of its biological activity.

scholarly journals Experimental Analysis of the Mechanical Properties and Resistivity of Tectonic Coal Samples with Different Particle Sizes

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2303
Author(s):  
Congyu Zhong ◽  
Liwen Cao ◽  
Jishi Geng ◽  
Zhihao Jiang ◽  
Shuai Zhang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Coalbed Methane ◽  
Coal Sample ◽  
Fine Particles ◽  
Particle Sizes ◽  
Tectonic Coal

Because of its weak cementation and abundant pores and cracks, it is difficult to obtain suitable samples of tectonic coal to test its mechanical properties. Therefore, the research and development of coalbed methane drilling and mining technology are restricted. In this study, tectonic coal samples are remodeled with different particle sizes to test the mechanical parameters and loading resistivity. The research results show that the particle size and gradation of tectonic coal significantly impact its uniaxial compressive strength and elastic modulus and affect changes in resistivity. As the converted particle size increases, the uniaxial compressive strength and elastic modulus decrease first and then tend to remain unchanged. The strength of the single-particle gradation coal sample decreases from 0.867 to 0.433 MPa and the elastic modulus decreases from 59.28 to 41.63 MPa with increasing particle size. The change in resistivity of the coal sample increases with increasing particle size, and the degree of resistivity variation decreases during the coal sample failure stage. In composite-particle gradation, the proportion of fine particles in the tectonic coal sample increases from 33% to 80%. Its strength and elastic modulus increase from 0.996 to 1.31 MPa and 83.96 to 125.4 MPa, respectively, and the resistivity change degree decreases. The proportion of medium particles or coarse particles increases, and the sample strength, elastic modulus, and resistivity changes all decrease.

scholarly journals Investigation of the kinetics of spontaneous combustion of the major coal seam in Dahuangshan mining area of the Southern Junggar coalfield, Xinjiang, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Shen ◽  
Qiang Zeng
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Coal Seam ◽  
Spontaneous Combustion ◽  
Heating Temperature ◽  
Characteristic Temperature ◽  
Mining Area ◽  
Particle Sizes ◽  
Coal Oxidation ◽  
Increasing Temperature

AbstractIn the present paper, with using diverse methods (including the SEM, the XRD, the TPO, the FTIR, and the TGA) , the authors analysed samples of the major coal seam in Dahuangshan Mining area with different particle sizes and with different heated temperatures (from 50 to 800 °C at regular intervals of 50 °C). The results from SEM and XRD showed that high temperature and high number of pores, fissures, and hierarchical structures in the coal samples could facilitate oxidation reactions and spontaneous combustion. A higher degree of graphitization and much greater number of aromatic microcrystalline structures facilitated spontaneous combustion. The results from TPO showed that the oxygen consumption rate of the coal samples increased exponentially with increasing temperature. The generation rates of different gases indicated that temperatures of 90 °C or 130 °C could accelerate coal oxidation. With increasing temperature, the coal oxidation rate increased, and the release of gaseous products was accelerated. The FTIR results showed that the amount of hydroxide radicals and oxygen-containing functional groups increased with the decline in particle size, indicating that a smaller particle size may facilitate the oxidation reaction and spontaneous combustion of coal. The absorbance and the functional group areas at different particle sizes were consistent with those of the heated coal samples, which decreased as the temperature rose. The results from TGA showed that the characteristic temperature T3 declined with decreasing particle size. After the sample with 0.15–0.18 mm particle size was heated, its carbon content decreased, and its mineral content increased, inhibiting coal oxidation. This result also shows that the activation energy of the heated samples tended to increase at the stage of high-temperature combustion with increasing heating temperature.

Effects of Particles Size of Nanosilica on Properties of Polybenzoxazine Nanocomposites

2015 ◽  
Vol 659 ◽  
pp. 394-398 ◽  
Author(s):  
Nutthaphon Liawthanyarat ◽  
Sarawut Rimdusit
Keyword(s):  
Particle Size ◽  
Silica Nanoparticles ◽  
Primary Particle ◽  
Mechanical And Thermal Properties ◽  
Particle Sizes ◽  
Barrier Effect ◽  
Degradation Temperature ◽  
Maximum Value ◽  
Wetting Behaviors ◽  
Composite Samples

Polybenzoxazine nanocomposites filled with three different sizes of silica nanoparticles are investigated for their mechanical and thermal properties. In this research, silica nanoparticles with primary particle sizes of 7, 14 and 40 nm were incorporated in polybenzoxazine matrix at a fixed content of 3% by weight. From the experimental results, the storage modulus of the polybenzoxazine nanocomposite was found to systematically increase with decreasing the particle sizes of nanosilica suggesting better reinforcement of the smaller particles. Glass transition temperature was found to slightly increase with the addition of the silica nanoparticles. The uniformity of the composite samples were also evaluated by thermogravimetric analysis to show good dispersion of the silica nanoparticles in the composite samples as a result of high processability of the benzoxazine resin used i.e. low A-stage viscosity with good wetting behaviors. Degradation temperature at 5% weight loss (Td,5) of polybenzoxazine nanocomposites filled with different particle sizes of silica nanoparticles was found to increase from the value of 325 °C of the neat polybenzoxazine to the maximum value of about 340 °C with an addition of the nanosilica of the smallest particle size used. Finally, the smaller nanosilica particle size was also found to show more pronounced effect on Td,5enhancement of the composite samples as a result of greater barrier effect from larger surface area of the smaller particles.

Effect of Particle Size on the Oil Yield and Catechin Compound Using Accelerated Solvent Extraction

2013 ◽  
Vol 60 (1) ◽  
Author(s):  
Mohd Azizi Che Yunus ◽  
Manzurudin Hasan ◽  
Norasikin Othman ◽  
Siti Hamidah Mohd-Setapar ◽  
Liza Md.-Salleh ◽  
...  
Keyword(s):  
Particle Size ◽  
Solvent Extraction ◽  
Accelerated Solvent Extraction ◽  
Extraction Time ◽  
Oil Yield ◽  
Particle Sizes ◽  
Experimental Range ◽  
Areca Catechu ◽  
Effect Of Particle Size ◽  
Extraction Cycle

Kajian ini bertujuan untuk mengkaji kesan saiz zarah ke atas pengekstrakan sebatian catechin daripada biji Areca catechu L. dengan menggunakan Pengekstrakan Pelarut Terpecut (PPT). Saiz zarah biji Areca catechu dipelbagaikan dari 75 μm sehingga 500 μm. Pengekstrakan telah dijalankan padaparameter tetap iaitu suhu (140oC), tekanan (1500 psi), masa (10 minit), isipadu semburan (60%) dan satu kitaran pengekstrakan, masing-masing. Hasil minyak peratusan yang lebih tinggi adalah 300 mg minyak / gram sampel (30.00% pati minyak) ditemui pada 125 μm. Walaubagaimanapun, kandungan catechin dalam pati minyak hanya 0.0375 mg catechin / gram sampel. Saiz zarah yang terbaik dalam julat uji kaji ini telah dikenal pasti pada 500 μm yang memberikan kandungan catechin yang tinggi iaitu 0.0515 mg catechin / gram sampel dari 247.5 mg minyak / gram sampel (24.75% pati minyak). Kata kunci: Saiz zarah; catechin; LC-MS-TOF; pengekstrakan pelarut terpecut The purpose of this work is to investigate the effects of particle size on the extraction of catechincompound from Areca catechu L. seeds by using Accelerated Solvent Extraction (ASE). The particle sizes of Areca catechu L. seeds are varied from 75 µm until 500 µm. The extraction is conducted at fixed parameters which are temperature (140oC), pressure (1500 psi), extraction time (10 minutes), flush volume (60%) and the static cycle is done for 1 extraction cycle respectively. Higher percentage oil yield of 300mg oil/gram of sample (30.00% oil yield) is found at 125 µm. However, the amount of catechin in oil yields is only 0.0375 mg of catechin/gram of sample. The best of particle size within the experimental range has been identified at 500 µm which gives a high content of catechin with 0.0515 mg Catechin/gram of sample from 247.5 mg oil/gram of sample (24.75% oil yield). Keywords: Particle size; catechin; LC-MS-TOF; accelerated solvent extraction

scholarly journals Space Charge Property of Polyethylene/Silica Nanocomposites at Different Elongations

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Can Wang ◽  
Youyuan Wang ◽  
Peng Fan ◽  
Ruijin Liao
Keyword(s):  
Particle Size ◽  
Space Charge ◽  
Dipole Model ◽  
Particle Sizes ◽  
Test Results ◽  
Silica Nanocomposites ◽  
Induced Dipole ◽  
Interface Characteristics ◽  
Space Charge Distribution ◽  
Charge Property

This paper prepares polyethylene/silica nanocomposites with concentrations of 3 wt% and 5 wt% by using silicon dioxide (SiO2) nanopowder (nanosilica) with particle sizes of 15 and 50 nm. Samples whose elongations are 3%, 6%, and 10% are prepared. Pulsed electroacoustic technique is applied to evaluate the space charge distribution in samples. Test results show that homocharge near electrodes is generated in the polyethylene/silica nanocomposites. Nanocomposites with a nanoparticle concentration of 3 wt% and particle size of 15 nm suppress the accumulation of space charge effectively. The amount of space charge in the samples increases with the increase in elongation. At an elongation of 10%, packet-like space charge is generated in polyethylene/silica nanocomposites with the concentration of 5 wt% and particle sizes of 15 and 50 nm. The packet-like space charge in nanocomposites whose particle size is 50 nm is more obvious than that in nanocomposites whose particle size is 15 nm. The experiment results are explained by applying interface characteristics, dipole model, and induced dipole model.

Influence of particle size and microbial phytase supplementation on the performance, nutrient utilisation and digestive tract parameters of broiler starters

2009 ◽  
Vol 49 (8) ◽  
pp. 704 ◽  
Author(s):  
A. M. Amerah ◽  
V. Ravindran
Keyword(s):  
Particle Size ◽  
Weight Gain ◽  
Digestive Tract ◽  
Feed Intake ◽  
Coarse Particle ◽  
Hammer Mill ◽  
Particle Sizes ◽  
Broiler Performance ◽  
Nutrient Utilisation ◽  
Microbial Phytase

The aim of the present experiment was to examine the interaction between particle size and microbial phytase supplementation on the performance, nutrient utilisation and digestive tract development of broiler starters fed maize-based diets. The experimental design was a 2 × 2 factorial arrangement of treatments evaluating two maize particle sizes (medium and coarse) and two levels of phytase supplementation (without or with 500 phytase units/kg diet). The two particle sizes were achieved by grinding the whole maize in a hammer mill to pass through 3- and 7-mm screens, respectively. Broiler starter diets, based on maize and soybean meal, were formulated to meet recommended requirements for major nutrients, except phosphorus. Each of the four diets was fed ad libitum to six pens of eight male broilers each, from day 1 to day 21 post-hatching. Phytase supplementation increased (P < 0.001) the feed intake and weight gain, and lowered (P < 0.05) feed per gain in both medium and coarse particle size diets. Coarse grinding improved (P < 0.05) weight gain, but had no effect (P > 0.05) on feed intake and feed per gain. No interactions (P > 0.05) between phytase supplementation and particle size were observed for any of the performance parameters. Phytase supplementation increased (P < 0.001) ileal phosphorus digestibility and toe ash content of birds fed the medium particle size diet, but had no effect in those fed the coarse particle size diet. Apparent metabolisable energy and ileal digestibility of calcium and nitrogen were not influenced by particle size or phytase supplementation. The present findings suggest that the effectiveness of supplemental phytase on broiler performance is not influenced by the particle size of maize.

scholarly journals A Gentle Sedimentation Process for Size-Selecting Porous Silicon Microparticles to Be Used for Drug Delivery Via Fine Gauge Needle Administration

Silicon ◽  
2020 ◽  
Author(s):  
Elida Nekovic ◽  
Catherine J. Storey ◽  
Andre Kaplan ◽  
Wolfgang Theis ◽  
Leigh T. Canham
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Porous Silicon ◽  
Particle Sizes ◽  
Size Distributions ◽  
Particle Agglomeration ◽  
Gas Generation ◽  
Intravitreal Drug Delivery ◽  
Median Diameter ◽  
Experimental Values

AbstractBiodegradable porous silicon (pSi) particles are under development for drug delivery applications. The optimum particle size very much depends on medical use, and microparticles can outperform nanoparticles in specific instances. Here we demonstrate the ability of sedimentation to size-select ultrasmall (1–10 μm) nanoporous microparticles in common solvents. Size tunability is quantified for 1–24 h of sedimentation. Experimental values of settling times in ethanol and water are compared to those calculated using Stokes’ Law. Differences can arise due to particle agglomeration, internal gas generation and incomplete wetting. Air-dried and supercritically-dried pSi powders are shown to have, for example, their median diameter d (0.5) particle sizes reduced from 13 to 1 μm and from 20 to 3 μm, using sedimentation times of 6 and 2 h respectively. Such filtered microparticles also have much narrower size distributions and are hence suitable for administration in 27 gauge microneedles, commonly used in intravitreal drug delivery.

The use of hollow sphere pigments as strength additives in paper and paperboard coatings—Part 1: The predictive nature of packing models on coating properties

TAPPI Journal ◽  
2020 ◽  
Vol 19 (11) ◽  
pp. 585-593
Author(s):  
ETHAN GLOR ◽  
BRIAN EINSLA ◽  
JOHN ROPER ◽  
JIAN YANG ◽  
VALERIY GINZBURG
Keyword(s):  
Particle Size ◽  
Hollow Sphere ◽  
Particle Packing ◽  
Particle Sizes ◽  
Coating Properties ◽  
Ideal System ◽  
Thermal Paper ◽  
Effect Of Particle Size ◽  
Low Levels ◽  
Better Than

Hollow sphere pigments (HSPs) are widely used at low levels in coated paper to increase coating bulk and to provide gloss to the final sheet. However, HSPs also provide an ideal system through which one can examine the effect of pigment size and particle packing within a coating due to their unimodal and tunable particle sizes. The work presented in Part 1 and Part 2 of this study will discuss the use of blends of traditional inorganic pigments and HSPs in coating formulations across a variety of applications for improved coating strength. Part 1 of this study focuses on the theory of bimodal spherical packing and demonstrates the predictive nature of packing models on the properties of coating systems containing HSPs of two different sizes. This study also examines conditions where the model fails by examining the effect of particle size on coating strength in sytems like thermal paper basecoats where the non-HSP component has a broad particle size distribution, and how these surprising trends can be used to generate better-than-expected thermal printing performance in systems with low HSP/clay ratios. Part 2 of this study focuses on the incorporation of HSPs of different particle sizes into paperboard formulations to affect coating strength and opacity.

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