Exposure to Nanoparticles in Thermal Spraying — Vigilance Towards the Operator and the Outside Environment

2021 ◽  
Author(s):  
G. Darut ◽  
S. Dieu ◽  
L. Meunier ◽  
B. Schnuriger ◽  
A. Vignes ◽  
...  
Keyword(s):  
Thermal Spraying ◽  
Submicron Particles ◽  
Straight Pipe ◽  
Filtration Equipment ◽  
Nickel Particles ◽  
Filtration System ◽  
High Concentrations ◽  
Emission Study ◽  
20 Nm ◽  
Nial Powder

Abstract This paper presents the results of an emission study on plasma spraying equipment and processes. Various measurements and samples were taken outside the spraying booth, at the operator level, and in the suction ducts upstream and downstream of the filtration equipment, creating a detailed profile of the aerosol emitted by the injection of NiAl powder in the plasma jet. The results show the existence of two families of particles, one ranging in size from 0.5 to 20 µm, the other of nanometric proportions. Concentrations of the larger particles were in the range of 600 cm-3 in the booth. As for submicron particles, concentrations of up to 107 cm-3 were observed but decreased significantly at the outlet of the filter system. The aerosol samples examined were dominated by a nanometric background of aggregates made up of oxidized nickel particles. Aggregates up to 100 nm in size, consisting of finer particles in the 5-20 nm size range, were found in high concentrations upstream of the filtration system. Great vigilance is thus required to protect equipment operators, an important part of which is placing dust collectors as close as possible to spraying booths connected by short, straight pipe runs.

The Ability of Thrombin Inhibitors to Reduce the Thrombin Activity Generated in Plasma on Extrinsic and Intrinsic Activation

1997 ◽  
Vol 77 (03) ◽  
pp. 498-503 ◽  
Author(s):  
D Prasa ◽  
L Svendsen ◽  
J Stürzebecher
Keyword(s):  
Active Site ◽  
Thrombin Generation ◽  
Anion Binding ◽  
Thrombin Inhibitors ◽  
Coagulation System ◽  
Thrombin Activity ◽  
Continuous Registration ◽  
High Concentrations ◽  
20 Nm ◽  
Generation Test

SummaryIn a thrombin generation test with continuous registration of thrombin activity in plasma we studied the ability of a variety of thrombin inhibitors of different type and mechanism of action to influence the activity of thrombin after activation of the coagulation system. Depending on the inhibitor, the peak of thrombin activity is delayed and/or reduced.By blocking the active site of generated thrombin inhibitors cause a concentration dependent reduction of the thrombin peak and inhibit feed-back reactions of thrombin resulting in a delay of thrombin generation. Highly potent synthetic active-site directed inhibitors (Ki ≤ 20 nM) reduce the thrombin activity formed in plasma after extrinsic or intrinsic activation with the same efficiency (IC50 0.1 - 0.6 μM) as hirudin. The delay and reduction of thrombin generation by inhibitors of the anion-binding exosite 1 of thrombin is only attributed to an inhibition of feed-back reactions of thrombin. For a 50% reduction of thrombin activity in plasma by this type of inhibitors relatively high concentrations were determined.

scholarly journals Photo-excited Toluidine Blue disaggregates the Repeat Tau and modulates cytoskeletal structure in neuronal cells

2020 ◽  
Author(s):  
Tushar Dubey ◽  
Nalini Vijay Gorantla ◽  
Subashchandrabose Chinnathambi
Keyword(s):  
Toluidine Blue ◽  
Neuronal Cells ◽  
Red Light ◽  
Microtubule Polymerization ◽  
Toxic Concentration ◽  
Significant Toxicity ◽  
Neuro2a Cells ◽  
High Concentrations ◽  
Novel Strategy ◽  
20 Nm

AbstractAlzheimer’s disease is a progressive neurological disorder characterized by the intracellular accumulation of Tau protein aggregates. Inhibition of protein aggregation by photo-excited dyes is emerging as novel strategy for the treatment of certain diseases. Toluidine Blue is a basic phenothiazine dye having potency of photo-excitation by irradiation with red light at 630±20 nm. In present work, we studied the effect of Toluidine Blue and photo-excited TB on aggregation of repeat Tau in-vitro using Thioflavin S fluorescence assay, SDS-PAGE and electron microscopy. Results show that TB efficiently inhabited the formation of higher order aggregates. Moreover, the photo-excited TB led to disaggregation of the mature repeat Tau fibrils. Further, studies on the effect of Toluidine blue on cell viability and cytoskeleton network of Neuro2acells show that TB was not toxic to neuronal cells at lower concentrations but at high concentrations (> 5 μM) both TB and photo-excited TB induced significant toxicity. Immunofluorescence studies on the cytoskeleton of Neuro2a cells show that Toluidine Blue and photo-excited Toluidine Blue treatment at non-toxic concentration of 0.5 μM stimulated formation of actin rich lamellipodia and filopodia structures. Tubulin networks were also differentially modulated after the treatment of Toluidine Blue and photo-excited Toluidine Blue. End Binding protein 1 (EB1) levels were observed to increase after Toluidine Blue and photo-excited Toluidine Blue treatment indicating the accelerated microtubule polymerization. The overall study suggested that Toluidine Blue inhibited the aggregation of soluble Tau and photo-excited Toluidine Blue disaggregated the pre-formed Tau filaments.

scholarly journals Aerosol from Biomass Combustion in Northern Europe: Influence of Meteorological Conditions and Air Mass History

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 789
Author(s):  
Jun Noda ◽  
Robert Bergström ◽  
Xiangrui Kong ◽  
Torbjörn L. Gustafsson ◽  
Borka Kovacevik ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Wind Speed ◽  
Biomass Burning ◽  
Meteorological Conditions ◽  
Submicron Particles ◽  
Biomass Combustion ◽  
Back Trajectory ◽  
Late Winter ◽  
Marine Origin ◽  
High Concentrations

Alkali-containing submicron particles were measured continuously during three months, including late winter and spring seasons in Gothenburg, Sweden. The overall aims were to characterize the ambient concentrations of combustion-related aerosol particles and to address the importance of local emissions and long-range transport for atmospheric concentrations in the urban background environment. K and Na concentrations in the particulate matter PM1 size range were measured by an Alkali aerosol mass spectrometer (Alkali-AMS) and a cluster analysis was conducted. Local meteorological conditions and trace gas and PM concentrations were also obtained for a nearby location. In addition, back trajectory analyses and chemical transport model (CTM) simulations were included for the evaluation. The Alkali-AMS cluster analysis indicated three major clusters: (1) biomass burning origin, (2) mixture of other combustion sources, and (3) marine origin. Low temperatures and low wind speed conditions correlated with high concentrations of K-containing particles, mainly owing to local and regional emissions from residential biomass combustion; transport of air masses from continental Europe also contribute to Cluster 1. The CTM results indicate that open biomass burning in the eastern parts of Europe may have contributed substantially to high PM2.5 concentrations (and to Cluster 1) during an episode in late March. According to the CTM results, the mixed cluster (2) is likely to include particles emitted from different source types and no single geographical source region seems to dominate for this cluster. The back trajectory analysis and meteorological conditions indicated that the marine origin cluster was correlated with westerly winds and high wind speed; this cluster had high concentrations of Na-containing particles, as expected for sea salt particles.

Application of Filtration System to Control Urban Non-Point Pollution

2007 ◽  
Vol 544-545 ◽  
pp. 661-664
Author(s):  
Seog Ku Kim ◽  
Young Im Kim ◽  
Byung Cheol Lee ◽  
Sung Won Kang ◽  
Bong Moon Kang ◽  
...  
Keyword(s):  
Water Flow ◽  
Removal Efficiency ◽  
Functional Material ◽  
Filtration Equipment ◽  
Filtration System ◽  
Flow Experiment ◽  
Receiving River ◽  
Flow Filtration ◽  
Sufficient Space ◽  
Point Pollution

Runoff from bridge impermeable surface is discharged directly into the receiving river or sewage pipe. However, generally, a bridge does not have sufficient space to place some treatment system. In this study, therefore, we investigated the down-flow filtration using expended polypropylene media (EPM) to treat runoff from bridge. Experiments were conducted employing down-flow filtration column (dh, 50600mm) to investigate the removal efficiency of pollutants. The EPM5, EPM10, EPM15 and f-EPM10 filters were developed from high molecular material, and were classified by different foaming rates and present of functional material. The experiment using f-EPM10 showed good hydraulic filtration performance without overflow for 1hr. But overflow, in the experiments using EPM5, EPM10 and EPM15, was observed within 1hr. Since f-EPM contains functional material, that can be improved water flow without clogging. The total SS removal efficiency of filtration equipment was rapidly decreased after overflow. In addition, a down-flow experiment, having slope of 15°, to avoid SS deposition at top of the column was carried out. Though SS deposition was found to be similar in two types flow, the flow of down-flow experiment, having slope of 15°, made progress without overflow for 3hr. This is because deposited SS didn’t intercept water inflow.

Factor XI Dependent and Independent Activation of Thrombin Activatable Fibrinolysis Inhibitor (TAFI) in Plasma Associated with Clot Formation

1999 ◽  
Vol 82 (12) ◽  
pp. 1703-1708 ◽  
Author(s):  
Laurent Mosnier ◽  
Joost Meijers ◽  
John Griffin ◽  
Bonno Bouma
Keyword(s):  
Clot Formation ◽  
Factor Xii ◽  
Intrinsic Pathway ◽  
Thrombin Activatable Fibrinolysis Inhibitor ◽  
Factor Xi ◽  
Normal Plasma ◽  
Factor Ii ◽  
Fibrinolysis Inhibitor ◽  
High Concentrations ◽  
20 Nm

SummaryThrombin Activatable Fibrinolysis Inhibitor (TAFI) also known as plasma procarboxypeptidase B is activated by relatively high concentrations of thrombin in a reaction stimulated by thrombomodulin. In plasma an intact factor XI-dependent feed back loop via the intrinsic pathway is necessary to generate sufficient thrombin for TAFI activation. This thrombin generation takes place after clot formation with consequent down-regulation of fibrinolysis. We developed a specific and sensitive assay for activated TAFI (TAFIa) and studied its factor XI-dependent generation during clot formation. In the absence of thrombomodulin, addition of 20 nM thrombin to normal plasma generated 5-10% of the amount of TAFIa generated by 20 nM thrombin in the presence of 8 nM thrombomodulin. Minimal activation of TAFI was detected in factor II deficient plasma when clotting was initiated by 20 nM thrombin. Addition of 320-640 nM of thrombin to factor II deficient plasma resulted in the same amount of TAFIa as in normal plasma, suggesting that ~50% of factor II has to be converted to thrombin for extensive activation of TAFI. A Mab that neutralizes activated factor XII had no effect on TAFI activation indicating that an intact contact system is not necessary for the activation of TAFI. The dependency of TAFI activation of factor XI was tested using a Mab that neutralizes activated factor XI. When plasmas from 13 healthy individuals were tested, this Mab reduced TAFI activation by 65% (range 35-89%). Our results indicate that activation of TAFI in serum after clot formation can be quantitated and that it takes place in both factor XI-dependent and factor XI-independent mechanisms.

Surface areas of turbostratic graphitic carbons prepared from a resin using nickel particles, 20 nm, as graphitization catalyst

Fuel ◽  
1981 ◽  
Vol 60 (11) ◽  
pp. 1099-1100 ◽  
Author(s):  
Asao Ōya ◽  
Eikichi Inoue ◽  
Sugio Ōtani ◽  
Harry Marsh
Keyword(s):  
Surface Areas ◽  
Nickel Particles ◽  
20 Nm

NiAl Oxidation and Corrosion Resistant Coatings Obtained by Thermal Spraying

2007 ◽  
Vol 23 ◽  
pp. 273-276 ◽  
Author(s):  
Radu L. Orban ◽  
Mariana Lucaci ◽  
Mario Rosso ◽  
Marco Actis Grande
Keyword(s):  
Coating Layer ◽  
Spray Deposition ◽  
Thermal Spraying ◽  
Processing Parameters ◽  
Corrosion Resistant ◽  
Powder Particles ◽  
Corrosion Resistant Coatings ◽  
Steel Substrates ◽  
Oxidation And Corrosion ◽  
Nial Powder

There are investigated the possibilities to avoid or at least to reduce the Al2O3 scales formation on NiAl powder particles at its plasma spray deposition on steel substrates. The optimum processing parameters and the necessity to surround the plasma jet by an inert gas have been established. In appropriate processing conditions, the obtained coating layer is formed by flattened particles, welded together and to the substrate, proving their melting during spraying. It is dense and adherent, consisting of NiAl with only small Al2O3 inclusions, proving the NiAl stability preserving without decomposition or a notable oxidation, as premises of its desired functionality achievement.

scholarly journals Nanodispersions of Polyelectrolytes Based on Humic Substances: Isolation, Physico-Chemical Characterization and Evaluation of Biological Activity

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1954
Author(s):  
Elena V. Uspenskaya ◽  
Anton V. Syroeshkin ◽  
Tatiana V. Pleteneva ◽  
Ilaha V. Kazimova ◽  
Tatiana V. Grebennikova ◽  
...  
Keyword(s):  
Targeted Delivery ◽  
Colloidal Particles ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Uv Spectra ◽  
Submicron Particles ◽  
Physico Chemical ◽  
Medicinal Substances ◽  
Fluorescent Radiation ◽  
High Concentrations

Natural polyelectrolytes, including in the form of complexes with colloidal particles, are increasingly used in pharmacy due to the possibility of regulated attachment of medicinal substances and their targeted delivery to the target organ. However, the formation, stability, and molecular-mass characteristics of polyelectrolyte nanodispersions (ND) vary depending on the nature and composition of the medium of their origin. This is due to the lack of standardized approaches to quality control and regulatory documentation for most natural ND. In this paper, we first introduced the isolation, followed by investigations into their physico-chemical properties and bioactivity. Using the dried droplet method, we were able to detect the “coffee ring effect”. Fractographic studies of the surface structure of EHA and FA dried samples using SEM showed its heterogeneity and the presence of submicron particles encapsulated in the internal molecular cavities of polyelectrolyte. FTIR spectroscopy revealed the ND chemical structure of benzo-α-pyron and benzo-γ-pyron, consisting of nanoparticles and a branched frame part. The main elements detected by X-ray fluorescence in humic substance extract and fulvic acid include Si, P, S, K, Ca, Mn, Fe, Cu, Zn, whereas Fe is in high concentrations. The UV-spectra and fluorescent radiation demonstrated the possibility of studying the effect of the fulvate chromone structure on its optical properties. It is shown that dilution of the initial solutions of polyelectrolytes 1:10 contributes to the detection of smaller nanoparticles and an increase in the absolute value of the negative ζ-potential as a factor of ND stability. A study of the EHS effect on the SARS-CoV-2 virus infectious titer in the Vero E6 cell showed the effective against virus both in the virucidal scheme (the SI is 11.90–22.43) and treatment/prevention scheme (the SI is 34.85–57.33). We assume that polyelectrolyte ND prevent the binding of the coronavirus spike glycoprotein to the receptor. Taking into account the results obtained, we expect that the developed approach can become unified for the standardization of the ND natural polyelectrolytes complex, which has great prospects for use in pharmacy and medicine as a drug with antiviral activity.

Intracellular calcium signals in response to bradykinin in individual neuroblastoma cells

1995 ◽  
Vol 269 (4) ◽  
pp. C841-C848 ◽  
Author(s):  
J. S. Coggan ◽  
S. H. Thompson
Keyword(s):  
Intracellular Calcium ◽  
Neuroblastoma Cells ◽  
Receptor Subtype ◽  
Half Time ◽  
Calcium Signals ◽  
Fura 2 ◽  
Low Concentrations ◽  
Intracellular Ca ◽  
High Concentrations ◽  
20 Nm

The Ca indicator fura 2 was used to study the modulation of cytoplasmic Ca by bradykinin (Bk) in single N1E-115 murine neuroblastoma cells. Increases in cytoplasmic Ca in response to Bk were mediated by the B2 receptor subtype. Responses to high concentrations of Bk (1-100 nM) were homogeneous and characterized by a rapidly rising transient that decayed to baseline in the continued presence of agonist, with a half-time of 15 s. Responses to low concentrations of Bk (100-500 pM) were more heterogeneous, with longer latencies and often with oscillations. Pretreatment with thapsigargin for 20 min prevented the Ca response, showing that the Ca change results from intracellular Ca release. Removal of external Ca had little effect on the response to Bk, indicating that the agonist does not activate Ca influx. The extent of Ca release and refilling after Bk was tested with ionomycin. A saturating dose of Bk (20 nM) mobilizes > 90% of stored Ca within 30 s, and this is replaced slowly. Replacement of external Na by N-methyl-D-glucamine to block Na/Ca exchange affected the Ca response, causing decreases in latency and in the period of Ca oscillations and increases in overall duration and peak amplitude of the response.

scholarly journals Anatomy of a selectively coassembled β-sheet peptide nanofiber

2020 ◽  
Vol 117 (9) ◽  
pp. 4710-4717 ◽  
Author(s):  
Qing Shao ◽  
Kong M. Wong ◽  
Dillon T. Seroski ◽  
Yiming Wang ◽  
Renjie Liu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Molecular Level ◽  
Form And Function ◽  
Transmission Electron ◽  
Peptide Pair ◽  
High Concentrations ◽  
Dynamics Simulations ◽  
And Function ◽  
20 Nm ◽  
Β Sheet

Peptide self-assembly, wherein molecule A associates with other A molecules to form fibrillar β-sheet structures, is common in nature and widely used to fabricate synthetic biomaterials. Selective coassembly of peptide pairs A and B with complementary partial charges is gaining interest due to its potential for expanding the form and function of biomaterials that can be realized. It has been hypothesized that charge-complementary peptides organize into alternating ABAB-type arrangements within assembled β-sheets, but no direct molecular-level evidence exists to support this interpretation. We report a computational and experimental approach to characterize molecular-level organization of the established peptide pair, CATCH. Discontinuous molecular dynamics simulations predict that CATCH(+) and CATCH(−) peptides coassemble but do not self-assemble. Two-layer β-sheet amyloid structures predominate, but off-pathway β-barrel oligomers are also predicted. At low concentration, transmission electron microscopy and dynamic light scattering identified nonfibrillar ∼20-nm oligomers, while at high concentrations elongated fibers predominated. Thioflavin T fluorimetry estimates rapid and near-stoichiometric coassembly of CATCH(+) and CATCH(−) at concentrations ≥100 μM. Natural abundance13C NMR and isotope-edited Fourier transform infrared spectroscopy indicate that CATCH(+) and CATCH(−) coassemble into two-component nanofibers instead of self-sorting. However,13C–13C dipolar recoupling solid-state NMR measurements also identify nonnegligible AA and BB interactions among a majority of AB pairs. Collectively, these results demonstrate that strictly alternating arrangements of β-strands predominate in coassembled CATCH structures, but deviations from perfect alternation occur. Off-pathway β-barrel oligomers are also suggested to occur in coassembled β-strand peptide systems.

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