scholarly journals Recent Laboratory Photochemical Studies and Their Relationship to the Photochemical Formation of Cometary Radicals

1989 ◽  
Vol 116 (1) ◽  
pp. 313-332
Author(s):  
William M. Jackson
Keyword(s):  
Laboratory Studies ◽  
Laboratory Evidence ◽  
Photochemical Formation ◽  
Laboratory Techniques ◽  
Unstable Molecules ◽  
Experimental Laboratory ◽  
Recent Laboratory

AbstractExperimental laboratory techniques used in studying the photochemistry of stable and unstable molecules are discussed. The laboratory evidence for the photochemical formation of C2 from C2H, C3 from C3H2, and NH from NH2 is presented. Other recent results obtained in laboratory studies of H2O, H2S, NH3, and HCN are reported.

scholarly journals Convergent Evolution Driven by Rifampin Exacerbates the Global Burden of Drug-Resistant Staphylococcus aureus

mSphere ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Romain Guérillot ◽  
Anders Gonçalves da Silva ◽  
Ian Monk ◽  
Stefano Giulieri ◽  
Takehiro Tomita ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Clinical Impact ◽  
Drug Resistant ◽  
Deleterious Mutations ◽  
Human Pathogen ◽  
Laboratory Studies ◽  
Increased Risk ◽  
Rifampin Resistance ◽  
Recent Laboratory

Increasing antibiotic resistance in the major human pathogen Staphylococcus aureus is threatening the ability to treat patients with these infections. Recent laboratory studies suggest that mutations in the gene commonly associated with rifampin resistance may also impact susceptibility to other last-line antibiotics in S. aureus; however, the overall frequency and clinical impact of these mutations are unknown. By mining a global collection of clinical S. aureus genomes and by mutagenesis experiments, this work reveals that common rifampin-induced rpoB mutations promote phenotypic plasticity that has led to the global emergence of stable, multidrug-resistant S. aureus lineages that are associated with increased risk of therapeutic failure through coresistance to other last-line antimicrobials. We recommend decreasing susceptibility breakpoints for rifampin to allow phenotypic detection of critical rpoB mutations conferring low resistance to rifampin and reconsidering the appropriate use of rifampin to reduce the fixation and spread of these deleterious mutations globally.

Conceptual Examination of Gas Phase Particulate Formation in Gas Turbine Combustors

1980 ◽  
Vol 102 (3) ◽  
pp. 613-618 ◽  
Author(s):  
A. S. Kesten ◽  
J. J. Sangiovanni ◽  
P. Goldberg
Keyword(s):  
Gas Turbine ◽  
Gas Phase ◽  
Mathematical Framework ◽  
Droplet Combustion ◽  
Laboratory Studies ◽  
Gas Turbine Combustors ◽  
Large Particles ◽  
Fuel Pyrolysis ◽  
Insight Into ◽  
Recent Laboratory

Recent laboratory studies of droplet combustion indicate the potential for substantial gas phase particulate formation even with single component hydrocarbon fuels. Formation of large particles has been observed in the neighborhood of burning droplet arrays, particularly when the droplets are closely spaced. To provide insight into the potential for particulate formation during the combustion of fuel droplet sprays in gas turbine combustors, a mathematical framework is developed for examining the formation of soot nuclei in droplet combustion. A simplified model of the chemistry of fuel pyrolysis and nuclei formation is used and a series of calculations is made to explore the sensitivity of soot nuclei formation to conditions typical of gas turbine combustion systems.

scholarly journals Glyceryl Tribenzoate: A Food Additive with Unique Properties to Be a Substitute for Cinnamon

2021 ◽  
Vol 6 (5) ◽  
Keyword(s):  
Neurodegenerative Disorders ◽  
Sodium Benzoate ◽  
Food Packaging ◽  
Disease Process ◽  
Laboratory Studies ◽  
Autoimmune Encephalomyelitis ◽  
The World ◽  
Ceylon Cinnamon ◽  
Recent Laboratory ◽  
Experimental Autoimmune

Cinnamon is a regularly used natural seasoning and flavouring material throughout the world for eras. Recent laboratory studies have demonstrated that oral cinnamon may be beneficial for different neuroinflammatory and neurodegenerative disorders such as multiple sclerosis (MS), Parkinson’s disease (PD), Alzheimer’s disease (AD), and Lewy body diseases (LBD). However, cinnamon’s certain limitations (e.g. unavailability of true Ceylon cinnamon throughout the world, impurities in ground cinnamon, etc.) have initiated an interest among researchers to find an alternate of cinnamon that can potentially deliver the same efficacy in the diseases mentioned above. Glyceryl tribenzoate (GTB) is a U.S. Food and Drug Administration (FDA)-approved flavoring ingredient that is used in food and food packaging industries. It has been found that similar to cinnamon, oral GTB is capable of upregulating regulatory T cells and suppressing the autoimmune disease process of experimental autoimmune encephalomyelitis, an animal model of MS. Moreover, both GTB and cinnamon metabolite sodium benzoate (NaB) have the potency to attenuate neurodegenerative pathology in a mouse model of Huntington disease (HD). Here, we have also demonstrated anti-inflammatory property of GTB in astrocytes and macrophages, a property that is also seen with cinnamon and its metabolite sodium benzoate (NaB). Therefore, here, we have made a sincere attempt to discuss the similarities and dissimilarities between cinnamon and GTB with a focus whether GTB has the potential to be considered as a substitute of cinnamon for neuroinflammatory and neurodegenerative disorders.

scholarly journals Fungal Sensing Skin

2020 ◽  
Author(s):  
Andrew Adamatzky ◽  
Antoni Gandia ◽  
Alessandro Chiolerio
Keyword(s):  
Laboratory Studies ◽  
Optical Stimulation ◽  
Sensing Skin ◽  
Experimental Laboratory ◽  
External Stimuli ◽  
And Robotics

Abstract BackgroundA fungal skin is a thin exible sheet of a living homogeneous mycelium made by a lamentous fungus. The skin could be used in future living architectures of adaptive buildings and as a sensing living skin for soft self-growing/adaptive robots.ResultsIn experimental laboratory studies we demonstrate that the fungal skin is capable for recognising mechanical and optical stimulation. The skin reacts dierently to loading of a weight, removal of the weight, and switching illumination on and off.ConclusionsThese are the rst experimental evidences that fungal materials can be used not only as mechanical `skeletons' in architecture and robotics but also as intelligent skins capable for recognition of external stimuli and sensorial fusion.

scholarly journals Modelling of gaseous dimethylamine in the global atmosphere: impacts of oxidation and aerosol uptake

2014 ◽  
Vol 14 (12) ◽  
pp. 17727-17748 ◽  
Author(s):  
F. Yu ◽  
G. Luo
Keyword(s):  
Transport Model ◽  
Anthropogenic Emissions ◽  
Laboratory Studies ◽  
Uptake Coefficient ◽  
Chemistry Transport Model ◽  
Global Emission ◽  
Order Of Magnitude ◽  
Urban Sites ◽  
Total Concentrations ◽  
Recent Laboratory

Abstract. Recent laboratory studies indicate that while a dimethylamine concentration ([DMA]) of several pptv can substantially enhance nucleation rates, such an enhancement drops significantly as [DMA] decreases below a few pptv. Here we study global distributions of amines with a chemistry transport model. DMA's lifetime is quite short (1–2 h in some regions) due to aerosol uptake and oxidation. Aerosol uptake is important over regions of high anthropogenic emissions, while the decrease of the uptake coefficient (γ) from 0.03 to 0.001 in these regions increases the modeled amine concentrations by a factor of ~5. Further decrease of γ from 0.001 to 0 has a small (<10%) effect on the predicted amine concentrations. With the estimated global emission flux, from the reference, our simulations indicate that [DMA] in the surface layer is generally less than 1 pptv over major continents and below 0.1 pptv over oceans, decreasing quickly with altitude. Total concentrations of methylamines are about one order of magnitude higher than that of DMA. A comparison of simulated and observed [DMA] shows that the values of the simulated [DMA] are close to the measured values for the various urban sites but are substantially lower (by 1–2 orders of magnitude) than those measured at the rural, coastal, and marine sites.

scholarly journals Infrared spectra of complex organic molecules in astronomically relevant ice matrices

2018 ◽  
Vol 611 ◽  
pp. A35 ◽  
Author(s):  
J. Terwisscha van Scheltinga ◽  
N. F. W. Ligterink ◽  
A. C. A. Boogert ◽  
E. F. van Dishoeck ◽  
H. Linnartz
Keyword(s):  
Gas Phase ◽  
Dimethyl Ether ◽  
Organic Molecules ◽  
Laboratory Data ◽  
Laboratory Studies ◽  
Astronomical Data ◽  
Astronomical Observations ◽  
Circumstellar Gas ◽  
Complex Organic ◽  
Recent Laboratory

Context. The number of identified complex organic molecules (COMs) in inter- and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic laboratory data of frozen COMs, embedded in ice matrices containing ingredients related to their formation scheme, are still largely lacking.Aim. This work provides infrared reference spectra of acetaldehyde (CH3CHO), ethanol (CH3CH2OH), and dimethyl ether (CH3OCH3) recorded in a variety of ice environments and for astronomically relevant temperatures, as needed to guide or interpret astronomical observations, specifically for upcoming James Webb Space Telescope observations.Methods. Fourier transform transmission spectroscopy (500–4000 cm−1/20–2.5 μm, 1.0 cm−1 resolution) was used to investigate solid acetaldehyde, ethanol and dimethyl ether, pure or mixed with water, CO, methanol, or CO:methanol. These species were deposited on a cryogenically cooled infrared transmissive window at 15 K. A heating ramp was applied, during which IR spectra were recorded until all ice constituents were thermally desorbed.Results. We present a large number of reference spectra that can be compared with astronomical data. Accurate band positions and band widths are provided for the studied ice mixtures and temperatures. Special efforts have been put into those bands of each molecule that are best suited for identification. For acetaldehyde the 7.427 and 5.803 μm bands are recommended, for ethanol the 11.36 and 7.240 μm bands are good candidates, and for dimethyl ether bands at 9.141 and 8.011 μm can be used. All spectra are publicly available in the Leiden Database for Ice.

Sign in / Sign up

Export Citation Format

Share Document