Propanal, an interstellar aldehyde – first infrared band strengths and other properties of the amorphous and crystalline forms

2020 ◽  
Vol 494 (4) ◽  
pp. 4606-4615
Author(s):  
Yuki Y Yarnall ◽  
Perry A Gerakines ◽  
Reggie L Hudson
Keyword(s):  
Observational Studies ◽  
Solid Phase ◽  
Molecular Ions ◽  
Infrared Band ◽  
Benchmark Data ◽  
Quantitative Measurements ◽  
Theoretical Investigations ◽  
Laboratory Investigations ◽  
Formation And Evolution ◽  
Crystalline Forms

ABSTRACT Chemical evolution in molecular clouds in the interstellar medium is well established, with the identification of over 200 molecules and molecular ions. Among the classes of interstellar organic compounds found are the aldehydes. However, laboratory work on the aldehydes has scarcely kept pace with astronomical discoveries as little quantitative solid-phase infrared (IR) data have been published on any of the aldehydes, and the same is true for important properties such as density, refractive indices, and vapour pressures. In this paper, we examine the IR spectra of solid propanal (HC(O)CH2CH3, propionaldehyde), along with several physical properties, for both the amorphous and crystalline forms of the compound. The quantitative measurements we report, such as IR intensities and optical constants, will be useful in laboratory investigations of the formation and evolution of propanal-containing ices, will serve as benchmark data for theoretical investigations, and will inform observational studies.

The Effect of Oxide Trenches on Defect Formation and Evolution in Ion-Implanted Silicon

2004 ◽  
Vol 810 ◽  
Author(s):  
Nina Burbure ◽  
Kevin S. Jones
Keyword(s):  
Silicon Oxide ◽  
Defect Formation ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Oxide Interface ◽  
Cross Sectional ◽  
Patterned Wafers ◽  
Edge Defects ◽  
Formation And Evolution ◽  
Spike Anneal

ABSTRACTPattern induced defects during advanced CMOS processing can lead to lower quality devices with high leakage currents. Within this study, the effects of oxide trenches on implant related defect formation and evolution in silicon patterned wafers is examined. Oxide filled trenches approximately 4000Å deep were patterned into 300 mm <100> silicon wafers. Patterning was followed by ion implantation of Si+ at energies ranging from 10 to 80 keV. Samples were amorphized with doses of 1×1015 atoms/cm2, 5×1015 atoms/cm2, and 1×1016 atoms/cm2. Two independent repeating structures were studied. The first structure is comprised of silicon oxide filled trench lines, 3.7μm wide spaced 12.5μm apart, while the second structure contains silicon squares, 0.6μm on a side, surrounded by a silicon oxide filled trench. Cross- sectional and planar view transmission electron microscopy (TEM) samples were used to examine the defect morphology after annealing at temperatures ranging from 700°C to 950°C and at times between 1 second and 1 minute. Following complete regrowth, an array of defects was observed to form near the surface at the silicon/silicon oxide interface. These trench edge defects appeared to nucleate at the amorphous-crystalline interface for all energies and doses studied. Upon a spike anneal at 700°C, it was observed that regrowth of the amorphous layer had completed except in the region near the trench edge. Thus, it is believed that this defect results from the pinning of the amorphous-crystalline interface along the trench edge during solid phase epitaxial regrowth (SPER).

scholarly journals Characterization of the Key Aroma Compounds in Marselan Wine by Gas Chromatography-Olfactometry, Quantitative Measurements, Aroma Recombination, and Omission Tests

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2978 ◽  
Author(s):  
Jiaheng Lyu ◽  
Yue Ma ◽  
Yan Xu ◽  
Yao Nie ◽  
Ke Tang
Keyword(s):  
Gas Chromatography ◽  
Solid Phase ◽  
Vitis Vinifera L ◽  
Active Compounds ◽  
Green Pepper ◽  
Flight Mass Spectrometry ◽  
Quantitative Measurements ◽  
Gas Chromatography Olfactometry ◽  
Analysis Application ◽  
Phenethyl Acetate

Key odorants of red wine made from the hybrid grapes of Marselan (Vitis vinifera L.) were isolated by solid-phase extraction (SPE) and explored by gas chromatography-olfactometry (GC-O) analysis. Application of aroma extract dilution analysis (AEDA) revealed 43 odor-active compounds, and 31 odorants among them were detected with flavor dilution (FD) factors ranging from 9 to 2187. Comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC-TOF-MS) were exploited to quantitate the aroma-active compounds with FD ≥9. The identification indicated β-damascenone as having the highest FD factors, followed by eugenol, 2,3-butanedione, citronellol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, phenethyl acetate, guaiacol, and 2-methoxy-4-vinylphenol. A total of 21 compounds were found to have odor activity values (OAVs) >1.0. Aroma reconstitution validation experiments showed a good similarity of blackberry, green pepper, honey, raspberry, caramel, smoky, and cinnamon aroma attributes between the original Marselan wine and the reconstructed wine. In addition, omission tests were carried out to further determine the contribution of odorants to the overall aroma.

scholarly journals Aluminium Binding to Modified Amyloid-β Peptides: Implications for Alzheimer’s Disease

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4536
Author(s):  
Cosmin Stefan Mocanu ◽  
Monica Jureschi ◽  
Gabi Drochioiu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Amyloid Β ◽  
Molecular Ions ◽  
Amino Acid Residues ◽  
Peptide Fragment ◽  
Peptide Fragments ◽  
Modified Peptides

Aluminium (Al) is clearly neurotoxic and considerable evidence exists that Al may play a role in the aetiology or pathogenesis of Alzheimer’s disease (AD). Nevertheless, the link between AD pathology and Al is still open to debate. Therefore, we investigated here the interaction of aluminium ions with two Aβ peptide fragments and their analogues. First, we synthesised by the Fmoc/tBu solid-phase peptide synthesis (SPPS) strategy using an automated peptide synthesiser two new peptides starting from the Aβ(1–16) native peptide fragment. For this purpose, the three histidine residues (H6, H13, and H14) of the Aβ(1–16) peptide were replaced by three alanine and three serine residues to form the modified peptides Aβ(1–16)A36,13,14 and Aβ(1–16)S36,13,14 (primary structures: H-1DAEFRADSGYEVAAQK16-NH2 and H-1DAEFRSDSGYEVSSQK16-NH2). In addition, the Aβ(9–16) peptide fragment (H-9GYEVHHQK16-NH2) and its glycine analogues, namely Aβ(9–16)G110, (H-9GGEVHHQK16-NH2), Aβ(9–16)G213,14 (H-9GYEVGGQK16-NH2), and Aβ(9–16)G310,13,14 (H-9GGEVGGQK16-NH2), were manually synthesised in order to study Al binding to more specific amino acid residues. Both the peptides and the corresponding complexes with aluminium were comparatively investigated by mass spectrometry (MS), circular dichroism spectroscopy (CD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). Al–peptide molecular ions and Al-fragment ions were unambiguously identified in the MS and MS/MS spectra. AFM images showed dramatic changes in the film morphology of peptides upon Al binding. Our findings from the investigation of N-terminal 1-16 and even 9-16 normal and modified sequences of Aβ peptides suggest that they have the capability to be involved in aluminium ion binding associated with AD.

scholarly journals Polymorphic Forms of Valinomycin Investigated by NMR Crystallography

2020 ◽  
Vol 21 (14) ◽  
pp. 4907
Author(s):  
Jiří Czernek ◽  
Jiří Brus
Keyword(s):  
Solid State Nmr ◽  
Large Scale ◽  
Solid Phase ◽  
Chemical Shifts ◽  
Conformational Stability ◽  
Structural Factors ◽  
Polymorphic Forms ◽  
Isotropic Chemical Shifts ◽  
Nmr Crystallography ◽  
Crystalline Forms

A dodecadepsipeptide valinomycin (VLM) has been most recently reported to be a potential anti-coronavirus drug that could be efficiently produced on a large scale. It is thus of importance to study solid-phase forms of VLM in order to be able to ensure its polymorphic purity in drug formulations. The previously available solid-state NMR (SSNMR) data are combined with the plane-wave DFT computations in the NMR crystallography framework. Structural/spectroscopical predictions (the PBE functional/GIPAW method) are obtained to characterize four polymorphs of VLM. Interactions which confer a conformational stability to VLM molecules in these crystalline forms are described in detail. The way how various structural factors affect the values of SSNMR parameters is thoroughly analyzed, and several SSNMR markers of the respective VLM polymorphs are identified. The markers are connected to hydrogen bonding effects upon the corresponding (13C/15N/1H) isotropic chemical shifts of (CO, Namid, Hamid, Hα) VLM backbone nuclei. These results are expected to be crucial for polymorph control of VLM and in probing its interactions in dosage forms.

scholarly journals Stability evaluation of compounded clonidine hydrochloride oral liquids based on a solid-phase extraction HPLC-UV method

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260279
Author(s):  
Daphné Coache ◽  
Mihaela Friciu ◽  
V. Gaëlle Roullin ◽  
Marianne Boulé ◽  
Jean-Marc Forest ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Phase Extraction ◽  
Quantitative Measurements ◽  
Clonidine Hydrochloride ◽  
Chemical Instabilities ◽  
The Stability ◽  
Physical And Chemical ◽  
Multiple Light Scattering

The present study aimed to assess the stability of clonidine hydrochloride oral liquids (20-μg/mL) prepared from two different generic tablets in Ora-Blend and stored in amber plastic bottles. Physical and chemical stabilities were evaluated over a period of 90 days at 25°C. Analytical challenges were overcome with the development of a new extraction procedure based on solid phase extraction to ensure efficient clonidine hydrochloride quantification. The absence of physical instabilities, evaluated by qualitative and quantitative measurements (static multiple light scattering), as well as the absence of chemical instabilities, evidenced by a stability-indicating HPLC-UV method, confirmed that a beyond-use date of 90 days was appropriate for these compounded oral liquids.

scholarly journals Terahertz Rotational Spectroscopy of Greenhouse Gases Using Long Interaction Path-Lengths

2021 ◽  
Vol 11 (3) ◽  
pp. 1229
Author(s):  
Arnaud Cuisset ◽  
Francis Hindle ◽  
Gaël Mouret ◽  
Robin Bocquet ◽  
Jonas Bruckhuisen ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Thz Spectroscopy ◽  
Rotational Spectroscopy ◽  
Line Intensities ◽  
Quantitative Measurements ◽  
Fabry Perot ◽  
Laboratory Investigations ◽  
Rotational Transitions ◽  
Path Lengths ◽  
Thz Absorption

Even if on-board mm-wave/THz heterodyne receivers have been developed to measure greenhouse gases (GHGs) atmospheric profiles, rotational spectroscopy rests under-exploited for their monitoring unlike IR rovibrational spectroscopy. The present study deals with the ability of THz spectroscopy using long interaction path-lengths for GHG laboratory investigations. High-resolution THz signatures of non-polar greenhouse molecules may be observed by probing very weak centrifugal distortion induced rotational transitions. To illustrate, new measurements on CH4 and CF4 have been carried out. For CH4, pure rotational transitions, recorded by cw-THz photomixing up to 2.6 THz in a White type cell adjusted to 20 m, have allowed to update the methane line list of atmospheric databases. Concerning CF4, Fabry-Perot THz absorption spectroscopy with a km effective pathlength was required to detect line intensities lower than 10−27 cm−1/(moleccm−2). Contrary to previous synchrotron-based FT-FIR measurements, the tetrahedral splitting of CF4 THz lines is fully resolved. Finally, quantitative measurements of N2O and O3 gas traces have been performed in an atmospheric simulation chamber using a submm-wave amplified multiplier chain coupled to a Chernin type multi-pass cell on a 200 m path-length. The THz monitoring of these two polar GHGs at tropospheric and stratospheric concentrations may be now considered.

scholarly journals Lightning and charge processes in brown dwarf and exoplanet atmospheres

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180398 ◽  
Author(s):  
Christiane Helling ◽  
Paul B. Rimmer
Keyword(s):  
Electron Beams ◽  
Three Dimensional ◽  
Brown Dwarfs ◽  
Molecular Ions ◽  
Cloud Formation ◽  
Brown Dwarf ◽  
Weather System ◽  
Hot Jupiters ◽  
Chemical Tracers ◽  
Formation And Evolution

The study of the composition of brown dwarf atmospheres helped to understand their formation and evolution. Similarly, the study of exoplanet atmospheres is expected to constrain their formation and evolutionary states. We use results from three-dimensional simulations, kinetic cloud formation and kinetic ion-neutral chemistry to investigate ionization processes that will affect their atmosphere chemistry: the dayside of super-hot Jupiters is dominated by atomic hydrogen, and not H 2 O. Such planetary atmospheres exhibit a substantial degree of thermal ionization and clouds only form on the nightside where lightning leaves chemical tracers (e.g. HCN) for possibly long enough to be detectable. External radiation may cause exoplanets to be enshrouded in a shell of highly ionized, H 3 + -forming gas and a weather-driven aurora may emerge. Brown dwarfs enable us to study the role of electron beams for the emergence of an extrasolar, weather system-driven aurora-like chemistry, and the effect of strong magnetic fields on cold atmospheric gases. Electron beams trigger the formation of H 3 + in the upper atmosphere of a brown dwarf (e.g. LSR-J1835), which may react with it to form hydronium, H 3 O + , as a longer lived chemical tracer. Brown dwarfs and super-hot gas giants may be excellent candidates to search for H 3 O + as an H 3 + product. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Ice photolysis of 2,2′,4,4′,6-pentabromodiphenyl ether (BDE-100): Laboratory investigations using solid phase microextraction

2012 ◽  
Vol 742 ◽  
pp. 90-96 ◽  
Author(s):  
Lucia Sanchez-Prado ◽  
Konstantina Kalafata ◽  
Sanja Risticevic ◽  
Janusz Pawliszyn ◽  
Marta Lores ◽  
...  
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Laboratory Investigations
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