Bias of the paleobotanical record as a consequence of variations in the chemical composition of higher vascular plant cuticles

Paleobiology ◽  
1991 ◽  
Vol 17 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Erik W. Tegelaar ◽  
Hans Kerp ◽  
Henk Visscher ◽  
Pieter A. Schenck ◽  
Jan W. de Leeuw
Keyword(s):  
Chemical Composition ◽  
Higher Plants ◽  
Vascular Plant ◽  
Chemical Characterization ◽  
Pyrolysis Gas ◽  
Plant Cuticles ◽  
The Subject ◽  
The Impact ◽  
Curie Point Pyrolysis

The impact of the variations in the chemical composition of higher vascular plant cuticles on their fossil record is usually not considered in paleobotanical and, more particularly, taphonomic studies. Here we address the subject with reference to the chemical characterization of insoluble cuticular matrices of a large variety of recent and fossil cuticles. The cuticles were analyzed using Curie-point pyrolysis-gas chromatographic techniques. Cuticular matrices of extant higher plants consist either of the biopolyester cutin, the insoluble, non-hydrolyzable polymethylenic biopolymer cutan, or a mixture of both biopolymers. In fossil cuticles an additional cuticular matrix type consisting of cutan and cutin-derived material is recognized. On the basis of the variations in their chemical composition and the different behavior of the cuticular constituents (viz., cutin and cutan) during diagenesis, it is concluded that the paleobotanical record of cuticles will be biased toward taxa originally having a significant amount of cutan in their cuticular matrix.

scholarly journals Nanotechnology in Roman Opaque Red Glass from the 2nd Century AD. Archaeometric Investigation in Red Sectilia from the Decoration of the Lucius Verus Villa in Rome

Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2597-2611 ◽  
Author(s):  
Mario Bandiera ◽  
Patrice Lehuédé ◽  
Marco Verità ◽  
Luis Alves ◽  
Isabelle Biron ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Chemical Characterization ◽  
Second Step ◽  
Colorimetric Analysis ◽  
Historical Sources ◽  
Pixe Analysis ◽  
X Ray ◽  
Colorimetric Measurements ◽  
Shed Light

This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.

Qualitative and Quantitative Characterization of Airport-related Ultrafine Particles using Liquid Chromatography – High-Resolution Mass Spectrometry (UHPLC/HRMS)

2021 ◽  
Author(s):  
Florian Ungeheuer ◽  
Diana Rose ◽  
Dominik van Pinxteren ◽  
Florian Ditas ◽  
Stefan Jacobi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Ultrafine Particles ◽  
Chemical Characterization ◽  
Engine Oil ◽  
Aircraft Emissions ◽  
Jet Engine ◽  
Qualitative And Quantitative ◽  
Ionization Mode ◽  
Lubrication Oils

<p>We present the results from a chemical characterization study of ultrafine particles (UFP), collected nearby Frankfurt International Airport where particle size distribution measurements showed high number concentrations for particles with a diameter <50 nm. Aluminium filter samples were collected at an air quality monitoring station in a distance of 4 km to Frankfurt airport, using the 13-stage cascade impactor Nano-MOUDI (MSP Model-115). The chemical characterization of the ultrafine particles in the size range of 0.010-0.018 μm, 0.018-0.032 μm and 0.032-0.056 μm was accomplished by the development of an optimized filter extraction method. An UHPLC method for chromatographic separation of homologous series of hydrophobic and high molecular weight organic compounds, followed by heated electrospray ionization (ESI) and mass analysis using an Orbitrap high-resolution mass spectrometer was developed. Using a non-target screening, ~200 compounds were detected in the positive ionization mode after filtering, in order to ensure high quality of the obtained data. We determined the molecular formula of positively charged adducts ([M+H]<sup>+</sup>; [M+Na]<sup>+</sup>), and for each impaction stage we present molecular fingerprints (Molecular weight vs Retention time, Kroll-diagram, Van-Krevelen-diagram, Kendrick mass defect plot) in order to visualize the complex chemical composition. The negative ionization mode led only to the detection of a few compounds (<20) for which reason the particle characterization focuses on the positive ionization mode. We found that the majority of detected compounds belong to homologous series of two different kinds of organic esters, which are base stocks of aircraft lubrication oils. In reference to five different jet engine lubrication oils of various manufacturers, we identified the corresponding lubricant base stocks and their additives in the ultrafine particles by the use of matching retention time, exact mass and MS/MS fragmentation pattern of single organic molecules. As the relevance of the chemical composition of UFP regarding human health is depending on the mass contribution of each compound we strived for quantification of the jet engine oil compounds. This was achieved by standard addition of purchased original standards to the native sample extracts. Two amines serving as stabilizers, one organophosphate used as an anti-wear agent/metal deactivator and two ester base stocks were quantified. Quantification of the two homologous ester series was carried out using one ester compound and cross-calibration. The quantitative determination is burdened by the uncertainty regarding sampling artefacts in the Nano-MOUDI. Therefore we characterized the cascade impactor in a lab experiment using the ester standard. Particle size distribution measurements conducted parallel to the filter sampling enables the determination of jet engine oil contribution to the UFP mass. Results indicate that aircraft emissions strongly influence the mass balance of 0.010-0.018 μm particles. This contribution decreases for bigger sized particles (0.018-0.056 μm) as presumably more sources get involved. The hereby-introduced method allows the qualitative and quantitative assignment of aircraft emissions towards the chemical composition and total mass of airport related ultrafine particles.</p>

scholarly journals A sensitive λ 3 mm line survey of L483

2019 ◽  
Vol 625 ◽  
pp. A147 ◽  
Author(s):  
M. Agúndez ◽  
N. Marcelino ◽  
J. Cernicharo ◽  
E. Roueff ◽  
M. Tafalla
Keyword(s):  
Chemical Composition ◽  
Chemical Characterization ◽  
Isotopic Ratios ◽  
Dark Cloud ◽  
Carbon Chains ◽  
Prestellar Cores ◽  
Low Mass ◽  
Line Survey ◽  
Molecular Abundances

An exhaustive chemical characterization of dense cores is mandatory to our understanding of chemical composition changes from a starless to a protostellar stage. However, only a few sources have had their molecular composition characterized in detail. Here we present a λ 3 mm line survey of L483, a dense core around a Class 0 protostar, which was observed with the IRAM 30 m telescope in the 80–116 GHz frequency range. We detected 71 molecules (140 including different isotopologs), most of which are present in the cold and quiescent ambient cloud according to their narrow lines (FWHM ~ 0.5 km s−1) and low rotational temperatures (≲10 K). Of particular interest among the detected molecules are the cis isomer of HCOOH, the complex organic molecules HCOOCH3, CH3OCH3, and C2H5OH, a wide variety of carbon chains, nitrogen oxides like N2O, and saturated molecules like CH3SH, in addition to eight new interstellar molecules (HCCO, HCS, HSC, NCCNH+, CNCN, NCO, H2NCO+, and NS+) whose detection has already been reported. In general, fractional molecular abundances in L483 are systematically lower than in TMC-1 (especially for carbon chains), tend to be higher than in L1544 and B1-b, and are similar to those in L1527. Apart from the overabundance of carbon chains in TMC-1, we find that L483 does not have a marked chemical differentiation with respect to starless/prestellar cores like TMC-1 and L1544, although it does chemically differentiate from Class 0 hot corino sources like IRAS 16293−2422. This fact suggests that the chemical composition of the ambient cloud of some Class 0 sources could be largely inherited from the dark cloud starless/prestellar phase. We explore the use of potential chemical evolutionary indicators, such as the HNCO/C3S, SO2/C2S, and CH3SH/C2S ratios, to trace the prestellar/protostellar transition. We also derived isotopic ratios for a variety of molecules, many of which show isotopic ratios close to the values for the local interstellar medium (remarkably all those involving 34S and 33S), while there are also several isotopic anomalies like an extreme depletion in 13C for one of the two isotopologs of c-C3H2, a drastic enrichment in 18O for SO and HNCO (SO being also largely enriched in 17O), and different abundances for the two 13C substituted species of C2H and the two 15N substituted species of N2H+. We report the first detection in space of some minor isotopologs like c-C3D. The exhaustive chemical characterization of L483 presented here, together with similar studies of other prestellar and protostellar sources, should allow us to identify the main factors that regulate the chemical composition of cores along the process of formation of low-mass protostars.

Characterization and destabilization of spent filter backwash water particles

2002 ◽  
Vol 2 (2) ◽  
pp. 115-122 ◽  
Author(s):  
A. Adin ◽  
L. Dean ◽  
F. Bonner ◽  
A. Nasser ◽  
Z. Huberman
Keyword(s):  
Water Treatment ◽  
Chemical Characterization ◽  
Physical Parameters ◽  
Ph Measurements ◽  
Particle Count ◽  
Water Treatment Plants ◽  
Physical Chemical ◽  
Organic Particles ◽  
The Impact

Inorganic and organic particles, including bacteria, viruses and parasites, which are retained within a granular filter during surface water filtration, are removed by backwashing the filter with clean water or water and air. The objective of the study was to characterize SFBW and determine its treatability by coagulation. Microbial and physical-chemical characterization of SFBW collected from a number of different water treatment plants was performed. Experiments to determine the impact of coagulation/flocculation on the SFBW samples were also conducted. SFBW was collected from six different water treatment plants and analyzed for microbial and physical parameters. Physical characterization was done on SFBW collected from all of the treatment plants. Turbidity and pH measurements were taken over the course of the backwash run, and the backwash samples were collected in two to four 20 L containers. A number of parameters were measured for the samples in each container, as well as for SFBW composites made by mixing equal portions of the container contents. The measured parameters included: turbidity, pH, TSS, DOC, UV-254 and alkalinity. Jar tests were carried out on individual containers, on SFBW composite and on SFBW composite that was allowed to settle for one hour. Turbidity and particle count data was collected for both settled and filtered samples.

scholarly journals Residential status of medical students as a factor affecting formative and summative academic performance in Forensic Medicine at Rehman Medical College, Peshawar, Pakistan

2020 ◽  
Vol 6 (1) ◽  
pp. 07-10
Author(s):  
Khalil-Ur -Rehman ◽  
Rizwan Faisal ◽  
Rizwan Qaisar ◽  
Mian Mujahid Shah
Keyword(s):  
Academic Performance ◽  
Medical Students ◽  
Forensic Medicine ◽  
Residential Status ◽  
Medical College ◽  
Significant Difference ◽  
The Subject ◽  
The Mean ◽  
The Impact

Introduction: A rigorous characterization of the impact of residential status of medical students (hostelites vs. day scholars) on the particulars of their academic performance has been lacking in Pakistan. Objective: To determine the relation of residential status of third year MBBS students to their academic performance in Forensic Medicine based on comparison of their pre-professional and professional examinations results during 2019. Materials & Methods: A comparative study was conducted from August to October 2019 on the examination performance of third year MBBS students of Rehman Medical College, Peshawar in the subject of Forensic Medicine. The results of theory and viva pre-professional and professional examinations were compared and categorized by residential status of students (Hostelites or Day Scholars). Students were categorized into groups according to their academic performance. Descriptive and Comparative data analysis was performed by SPSS 22.0, keeping p≤0.05 as significant. Results: No significant difference was found in the mean marks of hostelites and day scholars in pre-professional and professional examinations. The trend of significant improvement from pre-professional to professional examinations was similar in both groups, and it applied to both the theory and viva examinations. A significant correlation existed between the performance in two examinations among all students with no difference between the hostelites and day scholars. Conclusion: Residential status of MBBS students had no effect on their academic performance in the subject of Forensic Medicine. Keywords: Academic performance, Forensic Medicine, hostelites, day scholars

scholarly journals Exploitation of Bentonite for Wastewater Treatment

2021 ◽  
Author(s):  
Kali Abderrahim ◽  
Loulidi Ilyasse ◽  
Amar Abdelouahed ◽  
Boukhlifi Fatima ◽  
Hadey Chaimaa ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Phenol Adsorption ◽  
Significant Percentage ◽  
Adsorption Study ◽  
The Subject ◽  
Uv Visible ◽  
Xrd Techniques ◽  
Kinetics Of ◽  
Langmuir And Freundlich Models

Bentonite is a clay with interesting surface properties (affinity for water, adsorption capacity for electro-positive compounds….). The characteristics and clarifying properties of bentonite from various companies are the subject of numerous studies. The present work focuses on the study of the efficiency of bentonite and modified bentonite to purify aqueous solutions containing organic pollutants such as phenol. First, before starting the adsorption study, a physical–chemical characterization of the clay by FTIR, BET and XRD techniques was undertaken. The specific surface of the bentonite is calculated by BET. Then, the study of isotherms and kinetics of phenol adsorption on commercial BTC showed that this pollutant can be removed from liquid effluents with a significant percentage. Langmuir and Freundlich models were applied. Finally, the kinetic study performed by UV–Visible was reproduced by FTIR spectroscopy.

scholarly journals Chemical characterization of rainwater at Akkalkuwa, India

MAUSAM ◽  
2021 ◽  
Vol 62 (3) ◽  
pp. 425-432
Author(s):  
P.R. SALVE ◽  
T. GOBRE ◽  
R.J. KRUPADAM ◽  
S. SHASTRY ◽  
A. BANSIWAL ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Major Ions ◽  
Chemical Characterization ◽  
Relative Magnitude ◽  
Southwest Monsoon ◽  
Neutralization Factor ◽  
Major Anions ◽  
Major Factors ◽  
Cloud Process

The chemical composition of rainwater changes from place to place and region to region under the influence of several major factors, viz., topography, its distance from sea and overall rainfall pattern. The present study investigated the chemical composition of precipitation at Akkalkuwa, district Nandurbar, in the State Maharashtra during southwest monsoon. The rainwater samples were collected on event basis during June-September 2008 and were analyzed for pH, major anions (F, Cl, NO3, SO4) and cations (Ca, Mg, Na, K, NH4). The pH varied from 6.0 and 6.8 with an average of 6.29 ± 0.23 indicating alkaline nature and dominance of Ca in precipitation. The relative magnitude of major ions in precipitation follows the pattern as Ca>Cl>Na>SO4>NO3>HCO3>NH4>Mg>K>F>H. The Neutralization factor (NF) was found to be NFCa = 0.95, NFNH4 = 0.31, NFMg = 0.27 and NFK = 0.08 indicating below cloud process in which crustal components are responsible for neutralization of anions. Significant correlation of NH4 with SO4 and NO3 was observed with correlation coefficient of r = 0.79 and 0.75, respectively.

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