scholarly journals Challenges in using CellTracker Green on foraminifers that host algal endosymbionts

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5304 ◽  
Author(s):  
Benjamin J. Ross ◽  
Pamela Hallock
Keyword(s):  
Propylene Glycol ◽  
Laboratory Experiments ◽  
Fluorescent Microscopy ◽  
Chemical Exposure ◽  
Microbial Colonization ◽  
Total Darkness ◽  
Reaction Products ◽  
Metabolic Requirement ◽  
Survival Patterns ◽  
Short Time

The uses of fluorescent microscopy and fluorescent probes, such as the metabolically activated probe CellTracker™  Green CMFDA (CTG), have become common in studies of living Foraminifera. This metabolic requirement, as well as the relatively quick production of the fluorescent reaction products, makes CTG a prime candidate for determining mortality in bioassay and other laboratory experiments. Previous work with the foraminiferAmphistegina gibbosa, which hosts diatom endosymbionts, has shown that the species is capable of surviving both acute chemical exposure and extended periods of total darkness by entering a low-activity dormant state. This paper explores the use of CTG and fluorescent microscopy to determine mortality in such experiments, as well as to explore the physiology of dormant foraminifers. The application of CTG was found to be complicated by the autofluorescence of the diatom symbionts, which masks the signal of the CTG, as well as by interactions between CTG and propylene glycol, a chemical of interest known to cause dormancy. These complications necessitated adapting methods from earlier studies using CTG. Here we present observations on CTG fluorescence and autofluorescence inA. gibbosafollowing both chemical exposure and periods of total darkness. While CTG can indicate vital activity in dormant foraminifers, complications include underestimates of total survival and recovery, and falsely indicating dead individuals as live due to rapid microbial colonization. Nonetheless, the brightness of the CTG signal in dormant individuals exposed to propylene glycol supports previously published results of survival patterns inA. gibbosa. Observations of CTG fluorescence in individuals kept for extended periods in aphotic conditions indicate uptake of CTG may begin within 30 min of exposure to light, suggesting darkness-induced dormancy and subsequent recovery can occur on short time scales. These results suggest that CTG accurately reflects changes associated with dormancy, and can be useful in laboratory experiments utilizing symbiont-bearing foraminifers.

Hydrogenolysis of glucose and fructose in glycol solutions over CuO-MgO-ZrO2 catalyst

2020 ◽  
pp. 48-55
Author(s):  
M.E. Sharanda ◽  
◽  
E.A. Bondarenko ◽  
Keyword(s):  
Ethylene Glycol ◽  
Propylene Glycol ◽  
Flow Reactor ◽  
General Trend ◽  
Raw Materials ◽  
Reaction Products ◽  
Renewable Raw Materials ◽  
High Partial Pressure ◽  
Zro2 Catalyst ◽  
Phase Process

Ethylene glycol and propylene glycol are important representatives of polyols. On an industrial scale, they are obtained from petrochemical raw materials. Within a decade, significant efforts were made for the producing of polyols from biologically renewable raw materials - carbohydrates. The general trend for carbohydrate hydrogenolysis includes application of liquid-phase process with the use of modified metal-oxide catalysts, at 120-120 ° C and pressure of 3MPa or above. So high pressure is used for the reason to increase hydrogen solubility, and also due to the high partial pressure of low boiling solvents. We supposed that usage of high boiling solvents could allow hydrogenolysis to be performed at the lower pressure. Ethylene glycol and propylene glycol are of particular interest as such kind of solvent since they are both the main products of glucose hydrogenolysis. In this work, the process of hydrogenolysis of glucose and fructose over Cu / MgO-ZrO2 catalyst have been studied at temperature range of 160-200 °C and a pressure of 0.1-0.3 MPa in a flow reactor. The solvents were simultaneously the target products of the reaction - ethylene glycol and / or propylene glycol. Gas chromatography and 13C NMR were used for the reaction products identification. It was found that the solubility of glucose in propylene glycol is 21 % by weight, and in ethylene glycol 62% by weight. It was pointed out that the process of hydrogenolysis can take place at a pressure close to atmospheric. Under these conditions, the conversion of hexoses reaches 96-100 %. The reaction products are preferably propylene glycol and ethylene glycol. The total selectivity for C3-2 polyols is 90-94 %, that is higher than in the hydrogenolysis of glucose in aqueous solution.

scholarly journals Formation of flavorant–propylene Glycol Adducts With Novel Toxicological Properties in Chemically Unstable E-Cigarette Liquids

2018 ◽  
Vol 21 (9) ◽  
pp. 1248-1258 ◽  
Author(s):  
Hanno C Erythropel ◽  
Sairam V Jabba ◽  
Tamara M DeWinter ◽  
Melissa Mendizabal ◽  
Paul T Anastas ◽  
...  
Keyword(s):  
Propylene Glycol ◽  
Electronic Cigarettes ◽  
Aqueous Media ◽  
Chemical Species ◽  
Resonance Spectroscopy ◽  
Reaction Products ◽  
Chemical Systems ◽  
Toxicological Effects ◽  
Wide Range ◽  
Irritant Receptors

Abstract Introduction “Vaping” electronic cigarettes (e-cigarettes) is increasingly popular with youth, driven by the wide range of available flavors, often created using flavor aldehydes. The objective of this study was to examine whether flavor aldehydes remain stable in e-cigarette liquids or whether they undergo chemical reactions, forming novel chemical species that may cause harm to the user. Methods Gas chromatography was used to determine concentrations of flavor aldehydes and reaction products in e-liquids and vapor generated from a commercial e-cigarette. Stability of the detected reaction products in aqueous media was monitored by ultraviolet spectroscopy and nuclear magnetic resonance spectroscopy, and their effects on irritant receptors determined by fluorescent calcium imaging in HEK-293T cells. Results Flavor aldehydes including benzaldehyde, cinnamaldehyde, citral, ethylvanillin, and vanillin rapidly reacted with the e-liquid solvent propylene glycol (PG) after mixing, and upward of 40% of flavor aldehyde content was converted to flavor aldehyde PG acetals, which were also detected in commercial e-liquids. Vaping experiments showed carryover rates of 50%–80% of acetals to e-cigarette vapor. Acetals remained stable in physiological aqueous solution, with half-lives above 36 hours, suggesting they persist when inhaled by the user. Acetals activated aldehyde-sensitive TRPA1 irritant receptors and aldehyde-insensitive TRPV1 irritant receptors. Conclusions E-liquids are potentially reactive chemical systems in which new compounds can form after mixing of constituents and during storage, as demonstrated here for flavor aldehyde PG acetals, with unexpected toxicological effects. For regulatory purposes, a rigorous process is advised to monitor the potentially changing composition of e-liquids and e-vapors over time, to identify possible health hazards. Implications This study demonstrates that e-cigarette liquids can be chemically unstable, with reactions occurring between flavorant and solvent components immediately after mixing at room temperature. The resulting compounds have toxicological properties that differ from either the flavorants or solvent components. These findings suggest that the reporting of manufacturing ingredients of e-liquids is insufficient for a safety assessment. The establishment of an analytical workflow to detect newly formed compounds in e-liquids and their potential toxicological effects is imperative for regulatory risk analysis.

Rates of oxygen-depletion in granular Lambeth Group strata and evidence for barometric pumping

2020 ◽  
Vol 53 (4) ◽  
pp. 645-654
Author(s):  
T.G. Newman ◽  
R.C. Ghail
Keyword(s):  
Laboratory Experiments ◽  
Health And Safety ◽  
Barometric Pressure ◽  
Oxygen Depletion ◽  
Small Scale ◽  
Confined Space ◽  
Underground Construction ◽  
Barometric Pumping ◽  
Ground Investigation ◽  
Short Time

Laboratory experiments have been performed to demonstrate significant levels of oxygen depletion within samples of Upnor Formation of the Lambeth Group deposits. These have been used to explain the reasons for several incidences of confined space hypoxia during underground construction within the stratum beneath London. Further investigation, using a relatively small-scale field pump-out test, revealed the rapid effects of dewatering on the generation of hypoxic gas (within the ground) and that the amount of oxygen falls to fatal levels within a very short time after commencement of pumping. Monitoring of boreholes during ground investigation for the Thames Tideway Tunnel has indicated barometric control on the release of hypoxic gas from installations within granular deposits of the Lambeth Group, namely the Upnor Formation, as well as channel sand deposits within the Laminated Beds. In these, reduced levels of oxygen coincide with low and/or falling barometric pressure. Continuous 24-hour monitoring demonstrates that the reduction is almost instantaneous and has serious implications for the Health and Safety of underground construction personnel.

Microstructure of Ti5Si3–TiC–Ti3SiC2 and Ti5Si3–TiC nanocomposites in situ synthesized by spark plasma sintering

2004 ◽  
Vol 19 (10) ◽  
pp. 3004-3008 ◽  
Author(s):  
Lianjun Wang ◽  
Wan Jiang ◽  
Lidong Chen ◽  
Guangzhao Bai
Keyword(s):  
Spark Plasma Sintering ◽  
Microstructural Analysis ◽  
Molar Ratio ◽  
Reaction Products ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Fine Microstructure ◽  
Indentation Tests ◽  
Spark Plasma ◽  
Short Time

Nanostructured Ti5Si3–TiC–Ti3SiC2 and Ti5Si3–TiC composites were in situfabricated through the spark plasma sintering (SPS) technique using Ti and SiC powders as reactants. It was found that the composites could be prepared in arelatively short time (6 min at 1260 °C) above 98% theoretical density. The phase constituents and microstructures of the samples were analyzed by x-ray diffractionand observed by scanning electron microscopy. Transmission electron microscopywas used for detailed microstructural analysis. The results showed that the reaction products mainly consisted of Ti5Si3 and TiC phases or Ti5Si3, TiC and Ti3SiC2phases, depending on the molar ratio of reactants (Ti to SiC). The composites exhibited fine microstructure; TiC grain size was less than 200 nm. Fracturetoughness at room temperature was also measured by indentation tests.

Diurnal Activity in the Dusky Cockroach, Ectobius lapponicus L. (Blattodea)

1971 ◽  
Vol 2 (2) ◽  
pp. 132-138 ◽  
Author(s):  
Hans Dreisig
Keyword(s):  
Relative Humidity ◽  
Constant Temperature ◽  
Low Temperatures ◽  
Laboratory Experiments ◽  
Dark Period ◽  
Light Period ◽  
Total Darkness ◽  
Diurnal Activity ◽  
Males And Females ◽  
The Difference

AbstractThe activity of the cockroach Ectobius lapponicus was found to differ in males and females in the field, the males being active during the afternoon, the females after sunset. The difference was thought to be due to an inhibition by low temperatures in the males, displacing the activity towards an earlier period of the day. This is in accordance with a theory concerning sensitization, and different thresholds of release dependent on light and temperature as established for the stridulation in Orthoptera Ensifera and the locomotion in a domestic cockroach. A relationship between the amount of activity and the relative humidity was found in the nymphs. Laboratory experiments showed that the activity at constant temperature was released by a change from light to darkness. If low temperatures were applied during the dark period, the activity was displaced to the latter half of the light period. The influence of illumination on the activity was investigated, a faint illumination being more favourable than total darkness.

scholarly journals Crossed Molecular Beam Experiments of Radical-Neutral Reactions Relevant to the Formation of Hydrogen Deficient Molecules in Extraterrestrial Environments

2000 ◽  
Vol 197 ◽  
pp. 251-264 ◽  
Author(s):  
R. I. Kaiser ◽  
N. Balucani ◽  
O. Asvany ◽  
Y. T. Lee
Keyword(s):  
Laboratory Experiments ◽  
Molecular Beam ◽  
Carbon Clusters ◽  
Reaction Products ◽  
Chemical Reaction Dynamics ◽  
Cyano Radical ◽  
First Time ◽  
Beam Technique ◽  
Collision Complexes ◽  
Crossed Molecular Beam

During the last 5 years, laboratory experiments relevant to the formation of carbon-bearing molecules in extraterrestrial environments have been performed employing the crossed molecular beam technique and a high intensity source of ground state atomic carbon, C(3Pj). These investigations unraveled for the first time detailed information on the chemical reaction dynamics, involved collision complexes and intermediates, and – most important – reaction products of neutral-neutral reactions. Here, we extend these studies even further, and report on very recent crossed beam experiments of cyano radical, CN(2Σ+), reactions with unsaturated hydrocarbons to form nitriles in extraterrestrial environments and Saturn's moon Titan. Further, preliminary results on reactions of small carbon clusters and with acetylene, ethylene, and methylacetylene to synthesize hydrogen-deficient carbon-bearing molecules are presented.

Hydrogenolysis of Glycerol in Gas Phase on Cu-Cr Mixed Oxide Catalyst Doped with Ni

2017 ◽  
Vol 68 (5) ◽  
pp. 1118-1121
Author(s):  
Vasile Georgescu ◽  
Casen Panaitescu ◽  
Mihaela Bombos ◽  
Dorin Bombos
Keyword(s):  
Gas Phase ◽  
Propylene Glycol ◽  
Mixed Oxide ◽  
Oxide Catalyst ◽  
Molar Ratio ◽  
Main Reaction ◽  
Reaction Products ◽  
Glycerol Conversion ◽  
Mixed Oxide Catalyst ◽  
Temperature And Pressure

Hydrogenolysis of glycerol was conducted on catalyst of the type mixed oxide of Cu-Cr doped with NiO on g-Al2O3. The prepared catalyst was analyzed by XRD, IR and TPR. Catalytic tests were carried out on a laboratory plant in continuous flow system on a reactor equipped with heating mantle, at molar ratio of glycerol / hydrogen of 1/300, glycerol volume hourly space velocities 1000s-1, temperatures 200-220oC and pressures 3-5 bar. The main reaction products identified were propylene glycol and hydroxyacetone. Glycerol conversion increases with temperature and pressure on ranges of parameters studied. Selectivity to propylene glycol increases with increasing of temperature and pressure and the selectivity to hydroxyacetone decreases with increasing of temperature and pressure on the variation range of the parameters studied.

Intensified Viscosity Reduction of Heavy Oil by Using Reservoir Minerals and Chemical Agents in Aquathermolysis

2011 ◽  
Vol 236-238 ◽  
pp. 839-843 ◽  
Author(s):  
Qiu Yue Chen ◽  
Yong Jian Liu ◽  
Jie Zhao
Keyword(s):  
Molecular Weight ◽  
Aromatic Hydrocarbon ◽  
Heavy Oil ◽  
Laboratory Experiments ◽  
Average Molecular Weight ◽  
Reaction System ◽  
Reduction Ratio ◽  
Viscosity Reduction ◽  
Reaction Products ◽  
Chemical Agents

Through laboratory experiments with samples from Daqing and Liaohe oilfields, the effects of reservoir mineral,NiSO4 and tetrahydronaphthalene (THN) were investigated in the aquathermolysis (AT) of heavy oi1. The results indicate that, in contrast with simple AT, the addition of reservoir minerals leads to lower average molecular weight, higher contents of saturated and aromatic hydrocarbon and lower contents of resin and asphalting, and the viscosity reduction ratio of the two oi1 samples increases from 7.41% and 12.95% to 16.05% and 25.29% respectively, which means that reservoir minerals can catalyze the AT of heavy oi1.With the addition of NiSO4 and THN into the reaction system, the average molecular weight of the reaction products decreases further, the contents of saturated and aromatic hydrocarbon increase and the contents of resin and asphalting decrease further, the viscosity decreases greatly with a reduction ratio as high as 84.39%.

scholarly journals Solution Phase Synthesis of Chemical Libraries for Lead Discovery

1996 ◽  
Vol 1 (4) ◽  
pp. 179-186 ◽  
Author(s):  
Cheryl D. Garr ◽  
John R. Peterson ◽  
Lauri Schultz ◽  
Amy R. Oliver ◽  
Ted L. Underiner ◽  
...  
Keyword(s):  
Analytical Data ◽  
Synthesis Method ◽  
Computational Design ◽  
Significant Degree ◽  
Reaction Products ◽  
Lead Discovery ◽  
Drug Candidates ◽  
Design And Synthesis ◽  
The Individual ◽  
Short Time

By integrating advanced computational design and synthesis, a series of structurally diverse reaction products based on three core scaffolds were prepared by a propietary high throughput synthesis method. Incorporation of auto-mated work stations and sample handling techniques allowed for the production of more than 20,000 compounds in a relatively short time. A method to efficiently obtain quantitative and qualitative analytical data on these compounds was developed. Structural comparison of the individual members of this library with a database of clinical drug candidates revealed a significant degree of similarity based on Tanimoto coefficients.

scholarly journals Testing of biocidal properties of thermal insulation system during material life cycle

2021 ◽  
Vol 1205 (1) ◽  
pp. 012022
Author(s):  
I Kukletova ◽  
I Chromkova
Keyword(s):  
Thermal Insulation ◽  
Laboratory Experiments ◽  
Resistance Testing ◽  
Accelerated Ageing ◽  
Insulation System ◽  
Time Period ◽  
Biological Attack ◽  
Time Problem ◽  
Insulation Systems ◽  
Short Time

Abstract With the growing number of realized thermal insulation systems, fast growing number of buildings with facades attacked by microorganisms occurs. Such surface attack can occur even in the first years after thermal insulation completion, and it can be a serious problem in a very short time. Problem is both in realization and maintaining of thermal insulation, and directly in the used material. The paper presents results of laboratory experiments on resistance to biological attack, carried out for five commercial materials available on the Czech market. Before the experiments, materials were subjected to accelerated ageing for 4 and 10 years. Resistance testing comprises regulated application of algae and mould strains on samples and incubation in a defined environment. Materials resistant after ageing simulation of the longer time period were found as well as materials susceptible to attack already after completion of a facade set.

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