scholarly journals Characterization of total ecosystem scale biogenic VOC exchange at a Mediterranean oak-hornbeam forest

2015 ◽  
Vol 15 (19) ◽  
pp. 27627-27673 ◽  
Author(s):  
S. Schallhart ◽  
P. Rantala ◽  
E. Nemitz ◽  
D. Mogensen ◽  
R. Tillmann ◽  
...  
Keyword(s):  
Proton Transfer Reaction ◽  
Early Morning ◽  
Dew Point ◽  
Detection Methods ◽  
Fast Analysis ◽  
Po Valley ◽  
Advantages And Disadvantages ◽  
Automated Method ◽  
Biogenic Voc

Abstract. Recently, the number and amount of biogenically emitted volatile organic compounds (VOCs) has been discussed vigorously. Depending on the ecosystem the published number varies between a dozen and several hundred compounds. We present ecosystem exchange fluxes from a mixed oak-hornbeam forest in the Po Valley, Italy. The fluxes were measured by a proton transfer reaction-time-of-flight (PTR-ToF) mass spectrometer and calculated by the eddy covariance (EC) method. Detectable fluxes were observed for twelve compounds, dominated by isoprene, which comprised over 65 % of the total flux emission. The daily average of the total VOC emission was 9.5 nmol m-2 s-1. Methanol had the highest concentration and accounted for the largest deposition. Methanol seemed to be deposited to dew, as the deposition happened in the early morning, right after the calculated surface temperature came closest to the calculated dew point temperature. We estimated that up to 27 % of the upward flux of methyl vinyl ketone (MVK) and methacrolein (MACR) originated from atmospheric oxidation of isoprene. A comparison between two flux detection methods (classical/visual and automated) was made. Their respective advantages and disadvantages were discussed and the differences in their results shown. Both provide comparable results; however we recommend the automated method with a compound filter, which combines the fast analysis and better flux detection, without the overestimation due to double counting.

scholarly journals Characterization of total ecosystem-scale biogenic VOC exchange at a Mediterranean oak–hornbeam forest

2016 ◽  
Vol 16 (11) ◽  
pp. 7171-7194 ◽  
Author(s):  
Simon Schallhart ◽  
Pekka Rantala ◽  
Eiko Nemitz ◽  
Ditte Taipale ◽  
Ralf Tillmann ◽  
...  
Keyword(s):  
Proton Transfer Reaction ◽  
Early Morning ◽  
Dew Point ◽  
Downward Flux ◽  
Po Valley ◽  
Advantages And Disadvantages ◽  
Biogenic Voc ◽  
Volatile Organic ◽  
Upward Flux

Abstract. Recently, the number and amount of biogenically emitted volatile organic compounds (VOCs) has been discussed in great detail. Depending on the ecosystem, the published number varies between a dozen and several hundred compounds. We present ecosystem exchange fluxes from a mixed oak–hornbeam forest in the Po Valley, Italy. The fluxes were measured by a proton transfer reaction-time-of-flight (PTR-ToF) mass spectrometer and calculated using the eddy covariance (EC) method. Detectable fluxes were observed for up to 29 compounds, dominated by isoprene, which comprised over 60 % of the total upward flux (on a molar basis). The daily average of the total VOC upward flux was 10.4 nmol m−2 s−1. Methanol had the highest concentration and accounted for the largest downward flux. Methanol seemed to be deposited to dew, as the downward flux happened in the early morning, right after the calculated surface temperature came closest to the calculated dew point temperature.We estimated that up to 30 % of the upward flux of methyl vinyl ketone (MVK) and methacrolein (MACR) originated from atmospheric oxidation of isoprene. A comparison between two methods for the flux detection (manual and automated) was made. Their respective advantages and disadvantages were discussed and the differences in their results shown. Both provide comparable results.

scholarly journals Human Breathable Air in a Mediterranean Forest: Characterization of Monoterpene Concentrations under the Canopy

2020 ◽  
Vol 17 (12) ◽  
pp. 4391
Author(s):  
Albert Bach ◽  
Ana Maria Yáñez-Serrano ◽  
Joan Llusià ◽  
Iolanda Filella ◽  
Roser Maneja ◽  
...  
Keyword(s):  
Human Health ◽  
Proton Transfer Reaction ◽  
Early Morning ◽  
Ex Situ ◽  
North East ◽  
Diel Cycles ◽  
Concentration Peak ◽  
Early Afternoon ◽  
Human Health Effects

Monoterpenes have been identified as potential determinants of the human health effects induced by forest exposure. The present study characterizes the total monoterpene concentrations at nose height in a Mediterranean Holm oak forest located in North-East Iberian Peninsula during the annual emission peak (summer and autumn: June to November) using a Proton Transfer Reaction–Mass Spectrometry (PTR-MS). Results show a strong variability of the total monoterpene concentrations in season and daytime. The concentration peak appears during July and August. These two months displayed two average maxima in their diel cycles: One during early morning (from 6:00 to 8:00, 0.30 ppbv for July and 0.41 ppbv for August) and another one at early afternoon (from 13:00 to 15:00, 0.27 ppbv during July and 0.32 ppbv during August). Monoterpene concentrations were strongly related with the temperature (exponentially) and solar radiation (rectangular hyperbolic relationship). The concentrations registered here are similar or higher than in previous ex situ studies showcasing the effects of forests on human health. These findings provide relevant data for the scientific and healthcare community by improving the understanding of monoterpene dynamics at nose height and suggesting further research on the effects of forests on human health, particularly in the Mediterranean region.

scholarly journals Optimization of Neurite Tracing and Further Characterization of Human Monocyte-Derived-Neuronal-like Cells

2021 ◽  
Vol 11 (11) ◽  
pp. 1372
Author(s):  
Alfredo Bellon ◽  
Tuna Hasoglu ◽  
Mallory Peterson ◽  
Katherine Gao ◽  
Michael Chen ◽  
...  
Keyword(s):  
Human Monocyte ◽  
Live Cells ◽  
Neuronal Structure ◽  
Neuronal Markers ◽  
Advantages And Disadvantages ◽  
Automated Method ◽  
Neuronal Genes ◽  
Developing Neurons ◽  
Automated Methods

Deficits in neuronal structure are consistently associated with neurodevelopmental illnesses such as autism and schizophrenia. Nonetheless, the inability to access neurons from clinical patients has limited the study of early neurostructural changes directly in patients’ cells. This obstacle has been circumvented by differentiating stem cells into neurons, although the most used methodologies are time consuming. Therefore, we recently developed a relatively rapid (~20 days) protocol for transdifferentiating human circulating monocytes into neuronal-like cells. These monocyte-derived-neuronal-like cells (MDNCs) express several genes and proteins considered neuronal markers, such as MAP-2 and PSD-95. In addition, these cells conduct electrical activity. We have also previously shown that the structure of MDNCs is comparable with that of human developing neurons (HDNs) after 5 days in culture. Moreover, the neurostructure of MDNCs responds similarly to that of HDNs when exposed to colchicine and dopamine. In this manuscript, we expanded our characterization of MDNCs to include the expression of 12 neuronal genes, including tau. Following, we compared three different tracing approaches (two semi-automated and one automated) that enable tracing using photographs of live cells. This comparison is imperative for determining which neurite tracing method is more efficient in extracting neurostructural data from MDNCs and thus allowing researchers to take advantage of the faster yield provided by these neuronal-like cells. Surprisingly, it was one of the semi-automated methods that was the fastest, consisting of tracing only the longest primary and the longest secondary neurite. This tracing technique also detected more structural deficits. The only automated method tested, Volocity, detected MDNCs but failed to trace the entire neuritic length. Other advantages and disadvantages of the three tracing approaches are also presented and discussed.

Implantable neural interfaces

2018 ◽  
Author(s):  
Stefano Vassanelli
Keyword(s):  
Brain Function ◽  
Large Scale ◽  
Ionic Channels ◽  
Patch Clamp Technique ◽  
Advantages And Disadvantages ◽  
Optogenetic Stimulation ◽  
Physical Interfaces ◽  
The Brain

Establishing direct communication with the brain through physical interfaces is a fundamental strategy to investigate brain function. Starting with the patch-clamp technique in the seventies, neuroscience has moved from detailed characterization of ionic channels to the analysis of single neurons and, more recently, microcircuits in brain neuronal networks. Development of new biohybrid probes with electrodes for recording and stimulating neurons in the living animal is a natural consequence of this trend. The recent introduction of optogenetic stimulation and advanced high-resolution large-scale electrical recording approaches demonstrates this need. Brain implants for real-time neurophysiology are also opening new avenues for neuroprosthetics to restore brain function after injury or in neurological disorders. This chapter provides an overview on existing and emergent neurophysiology technologies with particular focus on those intended to interface neuronal microcircuits in vivo. Chemical, electrical, and optogenetic-based interfaces are presented, with an analysis of advantages and disadvantages of the different technical approaches.

scholarly journals Genetic and Pathogenic Characterization of QX(GI-19)-Recombinant Infectious Bronchitis Viruses in South Korea

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1163
Author(s):  
So-Youn Youn ◽  
Ji-Youn Lee ◽  
You-Chan Bae ◽  
Yong-Kuk Kwon ◽  
Hye-Ryoung Kim
Keyword(s):  
Phylogenetic Analysis ◽  
Disease Prevention ◽  
South Korea ◽  
Prevention And Control ◽  
Genetic Recombination ◽  
Detection Methods ◽  
Infectious Bronchitis ◽  
Reference Sequences ◽  
And Control

Infectious bronchitis viruses (IBVs) are evolving continuously via genetic drift and genetic recombination, making disease prevention and control difficult. In this study, we undertook genetic and pathogenic characterization of recombinant IBVs isolated from chickens in South Korea between 2003 and 2019. Phylogenetic analysis showed that 46 IBV isolates belonged to GI-19, which includes nephropathogenic IBVs. Ten isolates formed a new cluster, the genomic sequences of which were different from those of reference sequences. Recombination events in the S1 gene were identified, with putative parental strains identified as QX-like, KM91-like, and GI-15. Recombination detection methods identified three patterns (rGI-19-I, rGI-19-II, and rGI-19-III). To better understand the pathogenicity of recombinant IBVs, we compared the pathogenicity of GI-19 with that of the rGI-19s. The results suggest that rGI-19s may be more likely to cause trachea infections than GI-19, whereas rGI-19s were less pathogenic in the kidney. Additionally, the pathogenicity of rGI-19s varied according to the genotype of the major parent. These results indicate that genetic recombination between heterologous strains belonging to different genotypes has occurred, resulting in the emergence of new recombinant IBVs in South Korea.

Versatile thin layer spectroelectrochemical cell employing specular reflectance

1987 ◽  
Vol 65 (5) ◽  
pp. 919-923 ◽  
Author(s):  
A. Scott Hinman ◽  
Brad J. Pavelich
Keyword(s):  
Thin Layer ◽  
Specular Reflection ◽  
Incident Light ◽  
Tetrabutylammonium Perchlorate ◽  
Specular Reflectance ◽  
Advantages And Disadvantages ◽  
Ftir Characterization ◽  
Sandwich Type

A versatile thin layer spectroelectrochemical cell employing specular reflection of the incident light beam from the electrode surface is described. Its application to in-situ uv–vis and FTIR characterization of the products of electrochemical reactions and to thin layer voltammetry and coulometry as well as conventional cyclic voltammetry is demonstrated for the oxidation of tetraphenylporphinatozinc in dichloroethane/tetrabutylammonium perchlorate solution. The advantages and disadvantages of this type of cell as compared to more conventional sandwich type optically transparent thin layer electrodes are discussed.

scholarly journals Viruses and Virus Diseases of Rubus

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 168-182 ◽  
Author(s):  
Robert R. Martin ◽  
Stuart MacFarlane ◽  
Sead Sabanadzovic ◽  
Diego Quito ◽  
Bindu Poudel ◽  
...  
Keyword(s):  
Far East ◽  
Fruit Production ◽  
Detection Methods ◽  
Center Of Origin ◽  
The Family ◽  
Production Stages ◽  
Rubus Species ◽  
Polymerase Chain ◽  
Made In

Blackberry and raspberry are members of the family Rosaceae. They are classified in the genus Rubus, which comprises hundreds of species and has a center of origin in the Far East. Rubus is divided into 15 subgenera with blackberries classified in the Rubus (formerly Eubatus) and raspberries in the Idaeobatus subgenera. Rubus species are propagated vegetatively and are subject to infection by viruses during development, propagation, and fruit production stages. Reports of initial detection and symptoms of more than 30 viruses, virus-like diseases, and phytoplasmas affecting Rubus spp. were reviewed more than 20 years ago. Since the last review on Rubus viruses, significant progress has been made in the molecular characterization of many of the viruses that infect Rubus spp. Currently, reverse transcription–polymerase chain reaction detection methods are available for most of the viruses known to infect Rubus. The goals of this article are to update the knowledge on previously characterized viruses of Rubus, highlight recently described viruses, review the virus-induced symptoms, describe the advances made in their detection, and discuss our knowledge about several virus complexes that cause serious diseases in Rubus. Virus complexes have been identified recently as the major cause of diseases in blackberries and raspberries.

scholarly journals Characterization of gas-phase organics using proton transfer reaction time-of-flight mass spectrometry: fresh and aged residential wood combustion emissions

2016 ◽  
Author(s):  
Emily A. Bruns ◽  
Jay G. Slowik ◽  
Imad El Haddad ◽  
Dogushan Kilic ◽  
Felix Klein ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Reaction Time ◽  
Biomass Burning ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Wood Combustion ◽  
Flight Mass Spectrometry ◽  
Combustion Emissions ◽  
Organic Gases

Abstract. Organic gases emitted during the flaming phase of residential wood combustion are characterized individually and by functionality using proton transfer reaction time-of-flight mass spectrometry. The evolution of the organic gases is monitored during photochemical aging. Primary gaseous emissions are dominated by oxygenated species (e.g., acetic acid, acetaldehyde, phenol and methanol), many of which have deleterious health effects and play an important role in atmospheric processes such as secondary organic aerosol formation and ozone production. Residential wood combustion emissions differ considerably from open biomass burning in both absolute magnitude and relative composition. Ratios of acetonitrile, a potential biomass burning marker, to CO are considerably lower (~ 0.09 pptv ppbv−1) than those observed in air masses influenced by open burning (~ 1–2 pptv ppbv−1), which may make differentiation from background levels difficult, even in regions heavily impacted by residential wood burning. Considerable formic acid forms during aging (~ 200–600 mg kg−1 at an OH exposure of (4.5–5.5) × 107 molec  cm−3 h), indicating residential wood combustion can be an important local source for this acid, the quantities of which are currently underestimated in models. Phthalic anhydride, a naphthalene oxidation product, is also formed in considerable quantities with aging (~ 55–75 mg kg−1 at an OH exposure of (4.5–5.5) × 107 molec  cm−3 h). Although total NMOG emissions vary by up to a factor of ~ 9 between burns, SOA formation potential does not scale with total NMOG emissions and is similar in all experiments. This study is the first thorough characterization of both primary and aged organic gases from residential wood combustion and provides a benchmark for comparison of emissions generated under different burn parameters.

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