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Journal articles on the topic 'Resolution (Chemistry)'

Author: Grafiati

Published: 4 June 2021

Last updated: 24 January 2023

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1

Geiss, Andrew, Sam J. Silva, and Joseph C. Hardin. "Downscaling atmospheric chemistry simulations with physically consistent deep learning." Geoscientific Model Development 15, no. 17 (September 5, 2022): 6677–94. http://dx.doi.org/10.5194/gmd-15-6677-2022.

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Abstract. Recent advances in deep convolutional neural network (CNN)-based super resolution can be used to downscale atmospheric chemistry simulations with substantially higher accuracy than conventional downscaling methods. This work both demonstrates the downscaling capabilities of modern CNN-based single image super resolution and video super-resolution schemes and develops modifications to these schemes to ensure they are appropriate for use with physical science data. The CNN-based video super-resolution schemes in particular incur only 39 % to 54 % of the grid-cell-level error of interpolation schemes and generate outputs with extremely realistic small-scale variability based on multiple perceptual quality metrics while performing a large (8×10) increase in resolution in the spatial dimensions. Methods are introduced to strictly enforce physical conservation laws within CNNs, perform large and asymmetric resolution changes between common model grid resolutions, account for non-uniform grid-cell areas, super-resolve lognormally distributed datasets, and leverage additional inputs such as high-resolution climatologies and model state variables. High-resolution chemistry simulations are critical for modeling regional air quality and for understanding future climate, and CNN-based downscaling has the potential to generate these high-resolution simulations and ensembles at a fraction of the computational cost.

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2

Steinwandel, Ulrich P., Benjamin P. Moster, Thorsten Naab, Chia-Yu Hu, and Stefanie Walch. "Hot phase generation by supernovae in ISM simulations: resolution, chemistry, and thermal conduction." Monthly Notices of the Royal Astronomical Society 495, no. 1 (March 29, 2020): 1035–60. http://dx.doi.org/10.1093/mnras/staa821.

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ABSTRACT Supernovae (SNe) generate hot gas in the interstellar medium (ISM), help setting the ISM structure, and support the driving of outflows. It is important to resolve the hot gas generation for galaxy formation simulations at solar mass and sub-parsec resolution that realize individual SN explosions with ambient densities varying by several orders of magnitude in a realistic multiphase ISM. We test resolution requirements by simulating SN blast waves at three metallicities (Z = 0.01, 0.1, and 1 Z⊙), six densities and their respective equilibrium chemical compositions (n = 0.001–100 cm−3), and four mass resolutions (0.1–100 M⊙), in three dimensions. We include non-equilibrium cooling and chemistry, a homogeneous interstellar radiation field, and shielding with a modern pressure–energy smoothed particle hydrodynamics method including isotropic thermal conduction and a meshless-finite-mass solver. We find stronger resolution requirements for chemistry and hot phase generation than for momentum generation. While at 10 M⊙ the radial momenta at the end of the Sedov phase start converging, the hot phase generation and chemistry require higher resolutions to represent the neutral-to-ionized hydrogen fraction at the end of the Sedov phase correctly. Thermal conduction typically reduces the hot phase by 0.2 dex and has little impact on the chemical composition. In general, our 1 and 0.1 M⊙ results agree well with previous numerical and analytic estimates. We conclude that for the thermal energy injection SN model presented here resolutions higher than 10 M⊙ are required to model the chemistry, momentum, and hot phase generation in the multiphase ISM.

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3

Yu, Karen, Daniel J. Jacob, Jenny A. Fisher, Patrick S. Kim, Eloise A. Marais, Christopher C. Miller, Katherine R. Travis, et al. "Sensitivity to grid resolution in the ability of a chemical transport model to simulate observed oxidant chemistry under high-isoprene conditions." Atmospheric Chemistry and Physics 16, no. 7 (April 7, 2016): 4369–78. http://dx.doi.org/10.5194/acp-16-4369-2016.

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Abstract. Formation of ozone and organic aerosol in continental atmospheres depends on whether isoprene emitted by vegetation is oxidized by the high-NOx pathway (where peroxy radicals react with NO) or by low-NOx pathways (where peroxy radicals react by alternate channels, mostly with HO2). We used mixed layer observations from the SEAC4RS aircraft campaign over the Southeast US to test the ability of the GEOS-Chem chemical transport model at different grid resolutions (0.25° × 0.3125°, 2° × 2.5°, 4° × 5°) to simulate this chemistry under high-isoprene, variable-NOx conditions. Observations of isoprene and NOx over the Southeast US show a negative correlation, reflecting the spatial segregation of emissions; this negative correlation is captured in the model at 0.25° × 0.3125° resolution but not at coarser resolutions. As a result, less isoprene oxidation takes place by the high-NOx pathway in the model at 0.25° × 0.3125° resolution (54 %) than at coarser resolution (59 %). The cumulative probability distribution functions (CDFs) of NOx, isoprene, and ozone concentrations show little difference across model resolutions and good agreement with observations, while formaldehyde is overestimated at coarse resolution because excessive isoprene oxidation takes place by the high-NOx pathway with high formaldehyde yield. The good agreement of simulated and observed concentration variances implies that smaller-scale non-linearities (urban and power plant plumes) are not important on the regional scale. Correlations of simulated vs. observed concentrations do not improve with grid resolution because finer modes of variability are intrinsically more difficult to capture. Higher model resolution leads to decreased conversion of NOx to organic nitrates and increased conversion to nitric acid, with total reactive nitrogen oxides (NOy) changing little across model resolutions. Model concentrations in the lower free troposphere are also insensitive to grid resolution. The overall low sensitivity of modeled concentrations to grid resolution implies that coarse resolution is adequate when modeling continental boundary layer chemistry for global applications.

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4

Sanchez, Sergio I., Matthew W. Small, Shankar Sivaramakrishnan, Jian-guo Wen, Jian-Min Zuo, and Ralph G. Nuzzo. "Visualizing Materials Chemistry at Atomic Resolution." Analytical Chemistry 82, no. 7 (April 2010): 2599–607. http://dx.doi.org/10.1021/ac902089f.

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5

Grewe, Volker, Martin Dameris, Christine Fichter, and Robert Sausen. "Impact of aircraft NOx emissions. Part 1: Interactively coupled climate-chemistry simulations and sensitivities to climate-chemistry feedback, lightning and model resolution." Meteorologische Zeitschrift 11, no. 3 (August 2, 2002): 177–86. http://dx.doi.org/10.1127/0941-2948/2002/0011-0177.

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6

Charlton-Perez, C. L., M. J. Evans, J. H. Marsham, and J. G. Esler. "The impact of resolution on ship plume simulations with NO<sub>x</sub> chemistry." Atmospheric Chemistry and Physics 9, no. 19 (October 9, 2009): 7505–18. http://dx.doi.org/10.5194/acp-9-7505-2009.

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Abstract. A high resolution chemical transport model of the marine boundary layer is designed in order to investigate the detailed chemical evolution of a ship plume in a tropical location. To estimate systematic errors due to finite model resolution, otherwise identical simulations are run at a range of model resolutions. Notably, to obtain comparable plumes in the different simulations, it is found necessary to use an advection scheme consistent with the Large Eddy Model representation of sub-grid winds for those simulations with degraded resolution. Our simulations show that OH concentration, NOx lifetime and ozone production efficiency of the model change by 8%, 32% and 31% respectively between the highest (200 m×200 m×40 m) and lowest resolution (9600 m×9600 m×1920 m) simulations. Interpolating to the resolution of a typical global composition transport model (CTM, 5°×5°), suggests that a CTM overestimates OH, NOx lifetime and ozone production efficiency by approximately 15%, 55% and 59% respectively. For the first time, by explicitly degrading the model spatial resolution we show that there is a significant reduction in model skill in accurately simulating the aforementioned quantities due to the coarse resolution of these CTMs and the non-linear nature of atmospheric chemistry. These results are significant for the assessment and forecasting of the climate impact of ship NOx and indicate that for realistic representation of ship plume emissions in CTMs, some suitable parametrisation is necessary at current global model resolutions.

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7

Charlton-Perez, C. L., M. J. Evans, J. H. Marsham, and J. G. Esler. "The impact of resolution on ship plume simulations with NO<sub>x</sub> chemistry." Atmospheric Chemistry and Physics Discussions 9, no. 2 (March 31, 2009): 8587–618. http://dx.doi.org/10.5194/acpd-9-8587-2009.

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Abstract. A high resolution chemical transport model of the marine boundary layer is designed in order to investigate the detailed chemical evolution of a ship plume. To estimate systematic errors due to finite model resolution, otherwise identical simulations are run at a range of model resolutions. Notably, to obtain comparable plumes in the different simulations, it is found necessary to use an advection scheme consistent with the Large Eddy Model representation of sub-grid winds for those simulations with degraded resolution. Our simulations show that OH concentration, NOx lifetime and ozone production efficiency of the model change by 8%, 32% and 31% respectively between the highest (200 mx200 mx40 m) and lowest resolution (9600 mx9600 mx1920 m) simulations. Interpolating to the resolution of a typical global composition transport model (CTM, 5°x5°), suggests that a CTM overestimates OH, NOx lifetime and ozone production efficiency by approximately 15%, 55% and 59% respectively. For the first time, it is shown explicitly that the reduction in model skill is due to the coarse resolution of these CTMs and the non-linear nature of atmospheric chemistry. These results are significant for the assessment and forecasting of the climate impact of ship NOx and indicate that for realistic representation of ship plume emissions in CTMs, some suitable parametrisation is necessary at current global model resolutions.

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8

Li, Yunzhi, Richard L. Hunter, and Robert T. Mclver. "High-resolution mass spectrometer for protein chemistry." Nature 370, no. 6488 (August 1994): 393–95. http://dx.doi.org/10.1038/370393a0.

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9

Shapiro, Michael J., and John S. Gounarides. "High resolution MAS-NMR in combinatorial chemistry." Biotechnology and Bioengineering 71, no. 2 (2000): 130–48. http://dx.doi.org/10.1002/1097-0290(2000)71:2<130::aid-bit1004>3.0.co;2-r.

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10

Esler, J. G., G. J. Roelofs, M. O. Köhler, and F. M. O'Connor. "A quantitative analysis of grid-related systematic errors in oxidising capacity and ozone production rates in chemistry transport models." Atmospheric Chemistry and Physics 4, no. 7 (September 8, 2004): 1781–95. http://dx.doi.org/10.5194/acp-4-1781-2004.

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Abstract. Limited resolution in chemistry transport models (CTMs) is necessarily associated with systematic errors in the calculated chemistry, due to the artificial mixing of species on the scale of the model grid (grid-averaging). Here, the errors in calculated hydroxyl radical (OH) concentrations and ozone production rates 3 are investigated quantitatively using both direct observations and model results. Photochemical steady-state models of radical chemistry are exploited in each case to examine the effect on both OH and 3 of averaging relatively long-lived precursor species, such as O3, NOx, CO, H2O, etc. over different spatial scales. Changes in modelled 3 are estimated, independently of other model errors, by calculating the systematic effect of spatial averaging on the ozone production efficiency 1, defined as the ratio of ozone molecules produced per NOx molecule destroyed. Firstly, an investigation of in-flight measurements suggests that, at least in the northern midlatitude upper-troposphere/lower stratosphere, averaging precursor species on the scale of a T42 grid (2.75° x 2.75°) leads to a 15-20% increase in OH concentrations and a 5-10% increase in 1. Secondly, results from CTM model experiments are compared at different horizontal resolutions. Low resolution experiments are found to have significantly higher [OH] and 3 compared with high resolution experiments. The extent to which these differences may be explained by the systematic error in the model chemistry associated with grid size is estimated by degrading the high resolution data onto a low resolution grid and then recalculating 1 and [OH]. The change in calculated 1 is found to be significant and can account for much of the difference in 3 between the high and low resolution experiments. The calculated change in [OH] is less than the difference in [OH] found between the experiments, although the shortfall is likely to be due to the indirect effect of the change in modelled NOx, which is not accounted for in the calculation. It is argued that systematic errors caused by limited resolution need to be considered when evaluating the relative impacts of different pollutant sources on tropospheric ozone.

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11

Carter, C. Barry, and Stuart McKernan. "High-resolution imaging of ceramics." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 1 (August 1992): 112–13. http://dx.doi.org/10.1017/s0424820100120965.

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Ceramic materials have now been studied for many years using high-resolution transmission electron microscopy (HRTEM). The technique has had a major impact on our understanding of both the solid-sate chemistry of the materials themselves and the interfaces and defects present in the materials. The development of both aspects of the field have progressed in parallel as summarized in Figure 1. It is the purpose of this paper to review the current status and assess the needs for future studies.HRTEM is uniquely suited for examining the chemistry and structure of ceramic materials on the local scale. Although it does not directly give information on the chemical composition of these materials, it does provide information on the local crystal structure which can, in turn, be used to infer the local crystal chemistry. A particularly clear illustration of such an application is shown in Figure 2 where a small particle with the spinel structure has grown inside a matrix of olivine as a result of internal oxidation of the matrix. The selected-area diffraction pattern confirmed the FCC nature of the particle although due to its small size, the diffraction spots were all considerably elongated.

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12

Philip, Sajeev, Randall V. Martin, and Christoph A. Keller. "Sensitivity of chemistry-transport model simulations to the duration of chemical and transport operators: a case study with GEOS-Chem v10-01." Geoscientific Model Development 9, no. 5 (May 3, 2016): 1683–95. http://dx.doi.org/10.5194/gmd-9-1683-2016.

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Abstract. Chemistry-transport models involve considerable computational expense. Fine temporal resolution offers accuracy at the expense of computation time. Assessment is needed of the sensitivity of simulation accuracy to the duration of chemical and transport operators. We conduct a series of simulations with the GEOS-Chem chemistry-transport model at different temporal and spatial resolutions to examine the sensitivity of simulated atmospheric composition to operator duration. Subsequently, we compare the species simulated with operator durations from 10 to 60 min as typically used by global chemistry-transport models, and identify the operator durations that optimize both computational expense and simulation accuracy. We find that longer continuous transport operator duration increases concentrations of emitted species such as nitrogen oxides and carbon monoxide since a more homogeneous distribution reduces loss through chemical reactions and dry deposition. The increased concentrations of ozone precursors increase ozone production with longer transport operator duration. Longer chemical operator duration decreases sulfate and ammonium but increases nitrate due to feedbacks with in-cloud sulfur dioxide oxidation and aerosol thermodynamics. The simulation duration decreases by up to a factor of 5 from fine (5 min) to coarse (60 min) operator duration. We assess the change in simulation accuracy with resolution by comparing the root mean square difference in ground-level concentrations of nitrogen oxides, secondary inorganic aerosols, ozone and carbon monoxide with a finer temporal or spatial resolution taken as “truth”. Relative simulation error for these species increases by more than a factor of 5 from the shortest (5 min) to longest (60 min) operator duration. Chemical operator duration twice that of the transport operator duration offers more simulation accuracy per unit computation. However, the relative simulation error from coarser spatial resolution generally exceeds that from longer operator duration; e.g., degrading from 2° × 2.5° to 4° × 5° increases error by an order of magnitude. We recommend prioritizing fine spatial resolution before considering different operator durations in offline chemistry-transport models. We encourage chemistry-transport model users to specify in publications the durations of operators due to their effects on simulation accuracy.

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13

Olles, Joseph D., Ryan R. Wixom, Robert Knepper, and Alexander S. Tappan. "Observations of shock-induced chemistry with subnanosecond resolution." Applied Physics Letters 114, no. 21 (May 27, 2019): 214102. http://dx.doi.org/10.1063/1.5092230.

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14

Kihlborg, Lars. "High-resolution electron microscopy in solid state chemistry." Progress in Solid State Chemistry 20, no. 2 (January 1990): 101–33. http://dx.doi.org/10.1016/0079-6786(90)90004-y.

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15

Shapiro, Michael J., Jefferson Chin, Roger E. Marti, and Mark A. Jarosinski. "Enhanced resolution in MAS NMR for combinatorial chemistry." Tetrahedron Letters 38, no. 8 (February 1997): 1333–36. http://dx.doi.org/10.1016/s0040-4039(97)00092-0.

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16

Esler, J. G., G. J. Roelofs, M. O. Köhler, and F. M. O’Connor. "A quantitative analysis of grid-related systematic errors in oxidising capacity and ozone production rates in chemistry transport models." Atmospheric Chemistry and Physics Discussions 4, no. 3 (May 12, 2004): 2533–68. http://dx.doi.org/10.5194/acpd-4-2533-2004.

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Abstract. Limited resolution in chemistry transport models (CTMs) is necessarily associated with systematic errors in the calculated chemistry, due to the artificial mixing of species on the scale of the model grid (grid-averaging). Here, the errors in calculated hydroxyl radical (OH) concentrations and ozone production rates P(O3) are investigated quantitatively using both direct observations and model results. Photochemical steady-state models of radical chemistry are exploited in each case to examine the effect on both OH and P(O3) of averaging relatively long-lived precursor species, such as O3, NOx, CO, H2O, etc., over different spatial scales. Changes in modelled P(O3) are estimated, independently of other model errors, by calculating the systematic effect of spatial averaging on the ozone production efficiency εN, defined as the ratio of ozone molecules produced per NOx molecule destroyed. Firstly, an investigation of in-flight measurements suggests that, at least in the northern midlatitude upper-troposphere/lower stratosphere, averaging precursor species on the scale of a T42 grid (2.75°×2.75°) leads to a 15–20% increase in OH concentrations and a 5–10% increase in εN. Secondly, results from CTM model experiments are compared at different horizontal resolutions. Low resolution experiments are found to have significantly higher [OH] and P(O3) compared with high resolution experiments. The degree to which these differences may be explained by the systematic error associated with the model grid size is investigated by degrading the high resolution data onto a low resolution grid and then recalculating εN and [OH]. The change in calculated εN is found to be significant and can account for much of the difference in P(O3) between the high and low resolution experiments. The calculated change in [OH] is less than the difference in [OH] found between the experiments, although the shortfall is likely to be due to the indirect effect of the change in modelled NOx, which is not accounted for in the calculation. It is argued that systematic errors caused by limited resolution need to be considered when evaluating the relative impacts of different pollutant sources on tropospheric ozone.

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17

Schittmayer, Matthias, and Ruth Birner-Gruenberger. "Resolution Ladder for High-Resolution Mass Spectrometry." Analytical Chemistry 89, no. 18 (September 2017): 9611–15. http://dx.doi.org/10.1021/acs.analchem.7b02042.

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18

Balykbaeva, G. T., A. S. Tapalova, G. M. Abyzbekova, Sh O. Espenbetova, and K. Sh Arynova. "INORGANIC CHEMISTRY PROBLEM-BASED LEARNING." Bulletin of the Korkyt Ata Kyzylorda University 58, no. 3 (2021): 63–73. http://dx.doi.org/10.52081/bkaku.2021.v58.i3.072.

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The resolution of problem situations under the teacher’s guidance makes students compare, generalize, analyze phenomena, and not only memorize them mechanically. The processes of advancing and resolving problem situations are an unbroken chain, since when a problem is advanced, its solution begins simultaneously, which leads to the formulation of new problems. That is, a contradictory and continuous process of new scientific concepts active cognition is carried out. We see from the experience that using the methods of problem-based learning in the lessons that they promote development of cognitive activity, creative students’ independence, the formation of their worldview, intellectual development, and as a result, the improvement of the knowledge’s quality. Today, it is necessary when learning future specialists, in addition to the implementation of existing educational state standards in this specialty, to focus on the development of their creative qualities, creative thinking, which, ultimately, will promote to the formation of highly professional competent personnel.

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19

Avramov, Todor, Dan Vyenielo, Josue Gomez-Blanco, Swathi Adinarayanan, Javier Vargas, and Dong Si. "Deep Learning for Validating and Estimating Resolution of Cryo-Electron Microscopy Density Maps †." Molecules 24, no. 6 (March 26, 2019): 1181. http://dx.doi.org/10.3390/molecules24061181.

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Cryo-electron microscopy (cryo-EM) is becoming the imaging method of choice for determining protein structures. Many atomic structures have been resolved based on an exponentially growing number of published three-dimensional (3D) high resolution cryo-EM density maps. However, the resolution value claimed for the reconstructed 3D density map has been the topic of scientific debate for many years. The Fourier Shell Correlation (FSC) is the currently accepted cryo-EM resolution measure, but it can be subjective, manipulated, and has its own limitations. In this study, we first propose supervised deep learning methods to extract representative 3D features at high, medium and low resolutions from simulated protein density maps and build classification models that objectively validate resolutions of experimental 3D cryo-EM maps. Specifically, we build classification models based on dense artificial neural network (DNN) and 3D convolutional neural network (3D CNN) architectures. The trained models can classify a given 3D cryo-EM density map into one of three resolution levels: high, medium, low. The preliminary DNN and 3D CNN models achieved 92.73% accuracy and 99.75% accuracy on simulated test maps, respectively. Applying the DNN and 3D CNN models to thirty experimental cryo-EM maps achieved an agreement of 60.0% and 56.7%, respectively, with the author published resolution value of the density maps. We further augment these previous techniques and present preliminary results of a 3D U-Net model for local resolution classification. The model was trained to perform voxel-wise classification of 3D cryo-EM density maps into one of ten resolution classes, instead of a single global resolution value. The U-Net model achieved 88.3% and 94.7% accuracy when evaluated on experimental maps with local resolutions determined by MonoRes and ResMap methods, respectively. Our results suggest deep learning can potentially improve the resolution evaluation process of experimental cryo-EM maps.

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20

Lowe, D., D. Topping, and G. McFiggans. "Modelling multi-phase halogen chemistry in the remote marine boundary layer: investigation of the influence of aerosol size resolution on predicted gas- and condensed-phase chemistry." Atmospheric Chemistry and Physics Discussions 9, no. 2 (March 2, 2009): 5289–320. http://dx.doi.org/10.5194/acpd-9-5289-2009.

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Abstract. A coupled box model of photochemistry and aerosol microphysics which explicitly accounts for size-dependent chemical properties of the condensed-phase has been developed to simulate the multi-phase chemistry of chlorine, bromine and iodine in the marine boundary layer (MBL). The model contains separate seasalt and non-seasalt modes, each of which may be composed of 1–16 size-sections. By comparison of gaseous and aerosol compositions predicted using different size-resolutions with both fixed and size-dependent aerosol turnover rates, it was found that, for halogen-activation processes, the physical property initialisation of the aerosol-mode has a significant influence on gas-phase chemistry. Failure to adequately represent the appropriate physical properties can lead to substantial errors in gas-phase chemistry. The size-resolution of condensed-phase composition has a less significant influence on gas-phase chemistry.

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Lowe, D., D. Topping, and G. McFiggans. "Modelling multi-phase halogen chemistry in the remote marine boundary layer: investigation of the influence of aerosol size resolution on predicted gas- and condensed-phase chemistry." Atmospheric Chemistry and Physics 9, no. 14 (July 15, 2009): 4559–73. http://dx.doi.org/10.5194/acp-9-4559-2009.

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Abstract. A coupled box model of photochemistry and aerosol microphysics which explicitly accounts for size-dependent chemical properties of the condensed-phase has been developed to simulate the multi-phase chemistry of chlorine, bromine and iodine in the marine boundary layer (MBL). The model contains separate seasalt and non-seasalt modes, each of which may be composed of 1–16 size-bins. By comparison of gaseous and aerosol compositions predicted using different size-resolutions with both fixed and size-dependent aerosol turnover rates, it was found that, for halogen-activation processes, the physical property initialisation of the aerosol-mode has a significant influence on gas-phase chemistry. Failure to adequately represent the appropriate physical properties can lead to substantial errors in gas-phase chemistry. The size-resolution of condensed-phase composition has a less significant influence on gas-phase chemistry.

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22

Davies, Stephen G., Ai M. Fletcher, Paul M. Roberts, and James E. Thomson. "Mutual kinetic resolution: probing enantiorecognition phenomena and screening for kinetic resolution with racemic reagents." Organic & Biomolecular Chemistry 19, no. 13 (2021): 2847–55. http://dx.doi.org/10.1039/d0ob02151b.

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This review highlights recent examples of mutual kinetic resolutions and describes how this approach can be used as a powerful tool to screen for efficient kinetic/parallel kinetic resolution protocols.

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23

Holton, James M. "Resolution of the resolution limit." Acta Crystallographica Section A Foundations and Advances 73, a1 (May 26, 2017): a371. http://dx.doi.org/10.1107/s0108767317096386.

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24

Grant, David. "High resolution chromatography. High resolution capillary gas chromatography." Analytical Proceedings 29, no. 4 (1992): 156. http://dx.doi.org/10.1039/ap9922900156.

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Gradinaru, Viviana, Jennifer Treweek, Kristin Overton, and Karl Deisseroth. "Hydrogel-Tissue Chemistry: Principles and Applications." Annual Review of Biophysics 47, no. 1 (May 20, 2018): 355–76. http://dx.doi.org/10.1146/annurev-biophys-070317-032905.

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Over the past five years, a rapidly developing experimental approach has enabled high-resolution and high-content information retrieval from intact multicellular animal (metazoan) systems. New chemical and physical forms are created in the hydrogel-tissue chemistry process, and the retention and retrieval of crucial phenotypic information regarding constituent cells and molecules (and their joint interrelationships) are thereby enabled. For example, rich data sets defining both single-cell-resolution gene expression and single-cell-resolution activity during behavior can now be collected while still preserving information on three-dimensional positioning and/or brain-wide wiring of those very same neurons—even within vertebrate brains. This new approach and its variants, as applied to neuroscience, are beginning to illuminate the fundamental cellular and chemical representations of sensation, cognition, and action. More generally, reimagining metazoans as metareactants—or positionally defined three-dimensional graphs of constituent chemicals made available for ongoing functionalization, transformation, and readout—is stimulating innovation across biology and medicine.

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Santos, Rodrigo, Karen V. Pontes, and Idelfonso B. R. Nogueira. "Enantiomers and Their Resolution." Encyclopedia 2, no. 1 (January 14, 2022): 151–88. http://dx.doi.org/10.3390/encyclopedia2010011.

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Enantiomers share the same chemical formula but have different chemical structures, i.e., type of isomers. Enantiomers are present in several drugs, perfumes, food, and are a fundamental part of biomolecules. This subject is highly important for pharmaceutical companies. Enantiomeric drugs present different actuation in the human body; depending on the compound, one might combat the symptom, whereas its pair might cause damage. The separation of pairs of enantiomers requires a chiral environment that provokes a structural imbalance that conventional methods cannot provide. Enantioresolution is one of the most promissory studies that benefit several areas, such as pharmaceutical, biotechnology, food industry, and fine chemistry. Its resolution is of great importance, therefore, its main mechanisms of resolution will be explained herein.

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Strahan, S. E., and B. C. Polansky. "Implementation issues in chemistry and transport models." Atmospheric Chemistry and Physics Discussions 5, no. 5 (October 21, 2005): 10217–58. http://dx.doi.org/10.5194/acpd-5-10217-2005.

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Abstract. Offline chemistry and transport models (CTMs) are versatile tools for studying composition and climate issues requiring multi-decadal simulations. They are computationally fast compared to coupled chemistry climate models, making them well-suited for integrating sensitivity experiments necessary for understanding model performance and interpreting results. The archived meteorological fields used by CTMs can be implemented with lower horizontal or vertical resolution than the original meteorological fields in order to shorten integration time, but the effects of these shortcuts on transport processes must be understood if the CTM is to have credibility. In this paper we present a series of CTM experiments, each differing from another by a single feature of the implementation. Transport effects arising from changes in resolution and model lid height are evaluated using process-oriented diagnostics that intercompare CH4, O3, and age tracer carried in the simulations. Some of the diagnostics used are derived from observations and are shown as a reality check for the model. Processes evaluated include the tropical ascent, tropical-midlatitude exchange, the poleward circulation in the upper stratosphere, and the development of the Antarctic vortex. We find that faithful representation of stratospheric transport in this CTM using Lin and Rood advection is possible with a full mesosphere, ~1 km resolution in the lower stratosphere, and relatively low vertical resolution (>4 km spacing) in the middle stratosphere and above, but lowering the lid from the upper to lower mesosphere leads to less realistic constituent distributions in the upper stratosphere. Ultimately, this affects the polar lower stratosphere, but the effects are greater for the Antarctic than the Arctic. The fidelity of lower stratospheric transport requires realistic tropical and high latitude mixing barriers which are produced at 2°×2.5°, but not lower resolution. At 2°×2.5° resolution, the CTM produces a vortex capable of isolating perturbed chemistry (e.g. high Cly and low NOy) required for simulating polar ozone loss.

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Southcott, Lily, and Chris Orvig. "Inorganic radiopharmaceutical chemistry of oxine." Dalton Transactions 50, no. 45 (2021): 16451–58. http://dx.doi.org/10.1039/d1dt02685b.

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29

Grellier, L., V. Marécal, B. Josse, P. D. Hamer, T. J. Roberts, A. Aiuppa, and M. Pirre. "Towards a representation of halogen chemistry within volcanic plumes in a chemistry transport model." Geoscientific Model Development Discussions 7, no. 2 (April 28, 2014): 2581–650. http://dx.doi.org/10.5194/gmdd-7-2581-2014.

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Abstract. Volcanoes are a known source of halogens to the atmosphere. HBr volcanic emissions lead rapidly to the formation of BrO within volcanic plumes as shown by recent work based on observations and models. BrO, having a longer residence time in the atmosphere than HBr, is expected to have a significant impact on tropospheric chemistry, at least at the local and regional scales. The objective of this paper is to prepare a framework that will allow 3-D modelling of volcanic halogen emissions in order to determine their fate within the volcanic plume and then in the atmosphere at the regional and global scales. This work is based on a 1-D configuration of the chemistry transport model MOCAGE whose low computational cost allows us to perform a large set of sensitivity studies. This paper studies the Etna eruption on the 10 May 2008 that took place just before night time. Adaptations are made to MOCAGE to be able to produce the chemistry occurring within the volcanic plume. A simple sub-grid scale parameterization of the volcanic plume is implemented and tested. The use of this parameterization in a 0.5° × 0.5° configuration (typical regional resolution) has an influence on the partitioning between the various bromine compounds both during the eruption period and also during the night period immediately afterwards. During the day after the eruption, simulations both with and without parameterizations give very similar results that are consistent with the tropospheric column of BrO and SO2 in the volcanic plume derived from GOME-2 observations. Tests have been performed to evaluate the sensitivity of the results to the mixing between ambient air and the magmatic air at very high temperature at the crater vent that modifies the composition of the emission, and in particular the sulphate aerosol content that is key compound in the BrO production. Simulations show that the plume chemistry is not very sensitive to the assumptions used for the mixing parameter (relative quantity of ambient air mixed with magmatic air in the mixture) that is not well known. This is because there is no large change in the compounds limiting/favouring the BrO production in the plume. The impact of the model grid resolution is also tested in view of future 3-D-simulations at the global scale. A dilution of the emitted gases and aerosols is observed when using the typical global resolution (2°) as compared to a typical regional resolution (0.5°), as expected. Taking this into account, the results of the 2° resolution simulations are consistent with the GOME-2 observations. In general the simulations at 2° resolution are less efficient at producing BrO after the emission both with and without the subgrid-scale parameterization. The differences are mainly due to an interaction between concentration effects than stem from using a reduced volume in the 0.5° resolution combined with second order rate kinetics. The last series of tests were on the mean radius assumed for the sulphate aerosols that indirectly impacts the production of BrO by heterogeneous reactions. The simulations show that the BrO production is sensitive to this parameter with a stronger production when smaller aerosols are assumed. These results will be used to guide the implementation of volcanic halogen emissions in the 3-D configuration of MOCAGE.

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Glumac, Nick. "Absorption Spectroscopy Measurements in Optically Dense Explosive Fireballs Using a Modeless Broadband Dye Laser." Applied Spectroscopy 63, no. 9 (September 2009): 1075–80. http://dx.doi.org/10.1366/000370209789379268.

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A modeless broadband dye laser is applied to probe inside optically dense fireballs generated by high explosives using single-shot, high resolution absorption spectroscopy. Despite attenuation of the main beam by 98%, high signal-to-noise ratio absorption spectra of Al, Ti, and AlO are readily obtained at resolutions of 0.007 nm, and luminosity from the fireball is strongly rejected. Detection limits for atomic species are less than 200 ppb. The method offers good time resolution of chemistry within the fireball, and scaling laws suggest that this technique should be valid in explosives tests at least up to the gram scale.

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31

Lippens, G., R. Warrass, J. Wieruszeski, P. Rousselot-Pailley, and G. Chessari. "High Resolution Magic Angle Spinning NMR in Combinatorial Chemistry." Combinatorial Chemistry & High Throughput Screening 4, no. 4 (June 1, 2001): 333–51. http://dx.doi.org/10.2174/1386207013331048.

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Schwartz, Jonathan, Yi Jiang, Zichao Wendy Di, Tao Ma, Huihuo Zheng, Steve Rozeveld, and Robert Hovden. "Recovering Chemistry at Atomic Resolution using Multi-Modal Spectroscopy." Microscopy and Microanalysis 27, S1 (July 30, 2021): 1226–28. http://dx.doi.org/10.1017/s1431927621004608.

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ZAGOLSKI, F., V. PINEL, J. ROMIER, D. ALCAYDE, J. FONTANARI, J. P. GASTELLU-ETCHEGORRY, G. GIORDANO, G. MARTY, E. MOUGIN, and R. JOFFRE. "Forest canopy chemistry with high spectral resolution remote sensing." International Journal of Remote Sensing 17, no. 6 (April 1996): 1107–28. http://dx.doi.org/10.1080/01431169608949073.

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Ek, M., Q. M. Ramasse, L. Arnarson, P. G. Moses, C. F. Kisielowski, J. R. Jinschek, and S. Helveg. "Visualizing Redox Chemistry in Oxide Surfaces at Atomic-Resolution." Microscopy and Microanalysis 23, S1 (July 2017): 904–5. http://dx.doi.org/10.1017/s1431927617005189.

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Haughton, Louise, Jonathan M. J. Williams, and Jochen A. Zimmermann. "Enzymatic kinetic resolution of pantolactone:relevance to chiral auxiliary chemistry." Tetrahedron: Asymmetry 11, no. 8 (May 2000): 1697–701. http://dx.doi.org/10.1016/s0957-4166(00)00130-0.

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Szántay, C. "Resolution, chiral synthesis or what? Studies in alkaloid chemistry." Pure and Applied Chemistry 71, no. 6 (June 30, 1999): 1105–8. http://dx.doi.org/10.1351/pac199971061105.

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Constantinescu, Emil M., Adrian Sandu, and Gregory R. Carmichael. "Modeling atmospheric chemistry and transport with dynamic adaptive resolution." Computational Geosciences 12, no. 2 (January 11, 2008): 133–51. http://dx.doi.org/10.1007/s10596-007-9065-7.

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38

Shapiro, Michael J., and John S. Gounarides. "ChemInform Abstract: High Resolution MAS-NMR in Combinatorial Chemistry." ChemInform 32, no. 39 (May 24, 2010): no. http://dx.doi.org/10.1002/chin.200139300.

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39

Okamoto, Yoshio, Ryo Aburatani, and Koichi Hatada. "Chromatographic resolution." Journal of Chromatography A 448 (January 1988): 454–55. http://dx.doi.org/10.1016/s0021-9673(01)84612-4.

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Okamoto, Yoshio, Shiro Honda, Koichi Hatada, and Heimei Yuki. "Chromatographic resolution." Journal of Chromatography A 350 (January 1985): 127–34. http://dx.doi.org/10.1016/s0021-9673(01)93512-5.

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41

Barré, J., V. H. Peuch, J. L. Attié, L. El Amraoui, W. A. Lahoz, B. Josse, M. Claeyman, and P. Nédélec. "Stratosphere-troposphere ozone exchange from high resolution MLS ozone analyses." Atmospheric Chemistry and Physics 12, no. 14 (July 16, 2012): 6129–44. http://dx.doi.org/10.5194/acp-12-6129-2012.

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Abstract. We assimilate stratospheric ozone profiles from MLS (Microwave Limb Sounder) into the MOCAGE Chemistry Transport Model (CTM) to study Stratosphere-Troposphere Exchange (STE). This study uses two horizontal grid resolutions of 2° and 0.2°. The combined impacts of MLS ozone assimilation and high horizontal resolution are illustrated in two case studies where STE events occurred (23 June 2009 and 17 July 2009). At high resolution the filamentary structures of stratospheric air which characterise STE events are captured by the model. To test the impact of the assimilation and the resolution, we compare model outputs from different experiments (high resolution and low resolution; MLS assimilation run and free run) with independent data (MOZAIC aircraft ozone data; WOUDC ozone sonde network data). MLS ozone analyses show a better description of the Upper Troposphere Lower Stratosphere (UTLS) region and the stratospheric intrusions than the free model run. In particular, at high horizontal resolution the MLS ozone analyses present realistic filamentary ozone structures in the UTLS and laminae structures in the ozone profile. Despite a low aspect ratio between horizontal resolution and vertical resolution in the UTLS at high horizontal resolution, MLS ozone analyses improve the vertical structures of the ozone fields. Results from backward trajectories and ozone forecasts show that assimilation at high horizontal resolution of MLS ozone profiles between 10 hPa and 215 hPa has an impact on tropospheric ozone.

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Krol, M., S. Houweling, B. Bregman, M. van den Broek, A. Segers, P. van Velthoven, W. Peters, F. Dentener, and P. Bergamaschi. "The two-way nested global chemistry-transport zoom model TM5: algorithm and applications." Atmospheric Chemistry and Physics Discussions 4, no. 4 (July 28, 2004): 3975–4018. http://dx.doi.org/10.5194/acpd-4-3975-2004.

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Abstract. This paper describes the global chemistry Transport Model, version 5 (TM5) which allows two-way nested zooming. The model is used for global studies which require high resolution regionally but can work on a coarser resolution globally. The zoom algorithm introduces refinement in both space and time in some predefined regions. Boundary conditions of the zoom region are provided by a coarser parent grid and the results of the zoom area are communicated back to the parent. A case study using 222Rn measurements that were taken during the MINOS campaign reveals the advantages of local zooming. As a next step, it is investigated to what extent simulated concentrations over Europe are influenced by using an additional zoom domain over North America. An artificial ozone-like tracer is introduced with a lifetime of twenty days and simplified non-linear chemistry. The concentration differences at Mace Head (Ireland) are generally smaller than 10%, much smaller than the effects of the resolution enhancement over Europe. Thus, coarsening of resolution at some distance of a sampling station seems allowed. However, it is also noted that the budgets of the tracers change considerably due to resolution dependencies of, for instance, vertical transport. Due to the two-way nested algorithm, TM5 therefore offers a consistent tool to study the effects of grid refinement on global atmospheric chemistry issues like intercontinental transport of air pollution.

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43

Krol, M., S. Houweling, B. Bregman, M. van den Broek, A. Segers, P. van Velthoven, W. Peters, F. Dentener, and P. Bergamaschi. "The two-way nested global chemistry-transport zoom model TM5: algorithm and applications." Atmospheric Chemistry and Physics 5, no. 2 (February 10, 2005): 417–32. http://dx.doi.org/10.5194/acp-5-417-2005.

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Abstract. This paper describes the global chemistry Transport Model, version 5 (TM5) which allows two-way nested zooming. The model is used for global studies which require high resolution regionally but can work on a coarser resolution globally. The zoom algorithm introduces refinement in both space and time in some predefined regions. Boundary conditions of the zoom region are provided by a coarser parent grid and the results of the zoom area are communicated back to the parent. A case study using 222Rn measurements that were taken during the MINOS campaign reveals the advantages of local zooming. As a next step, it is investigated to what extent simulated concentrations over Europe are influenced by using an additional zoom domain over North America. An artificial ozone-like tracer is introduced with a lifetime of twenty days and simplified non-linear chemistry. The concentration differences at Mace Head (Ireland) are generally smaller than 10%, much smaller than the effects of the resolution enhancement over Europe. Thus, coarsening of resolution at some distance of a sampling station seems allowed. However, it is also noted that the budgets of the tracers change considerably due to resolution dependencies of, for instance, vertical transport. Due to the two-way nested algorithm, TM5 offers a consistent tool to study the effects of grid refinement on global atmospheric chemistry issues like intercontinental transport of air pollution.

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Mertens, Mariano, Astrid Kerkweg, Volker Grewe, Patrick Jöckel, and Robert Sausen. "Are contributions of emissions to ozone a matter of scale? – a study using MECO(n) (MESSy v2.50)." Geoscientific Model Development 13, no. 1 (January 31, 2020): 363–83. http://dx.doi.org/10.5194/gmd-13-363-2020.

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Abstract. Anthropogenic and natural emissions influence the tropospheric ozone budget, thereby affecting air quality and climate. To study the influence of different emission sources on the ozone budget, often source apportionment studies with a tagged tracer approach are performed. Studies investigating air quality issues usually rely on regional models with a fine spatial resolution, while studies focusing on climate-related questions often use coarsely resolved global models. It is well known that simulated ozone mixing ratios depend on the resolution of the model and the resolution of the emission inventory. Whether the contributions simulated using source apportionment approaches also depend on the model resolution, however, is still unclear. Therefore, this study attempts for the first time to analyse the impact of the model, the model resolution, and the emission inventory resolution on simulated ozone contributions using a diagnostic tagging method. The differences in the ozone contributions caused by these factors are compared with differences that arise from the usage of different emission inventories. To do so, we apply the MECO(n) (MESSy-fied ECHAM and COSMO models nested n times) model system which couples online a global chemistry-climate model with a regional chemistry-climate model equipped with a tagging scheme for source apportionment. The results of the global model (at 300 km horizontal resolution) are compared with the results of the regional model at 50 km (Europe) and 12 km (Germany) resolutions. Besides model-specific differences and biases that are discussed in detail, our results have important implications for other modelling studies and modellers applying source apportionment methods. First, contributions from anthropogenic emissions averaged over the continental scale are quite robust with respect to the model, model resolution, and emission inventory resolution. Second, differences on the regional scale caused by different models and model resolutions can be quite large, and regional models are indispensable for source apportionment studies on the subcontinental scale. Third, contributions from stratospheric ozone transported to the surface differ strongly between the models, mainly caused by differences in the efficiency of the vertical mixing. As stratospheric ozone plays an important role for ground level ozone, but the models show large differences in the amount of downward transported ozone, source apportionment methods should account for this source explicitly to better understand inter-model differences.

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45

Harrer, Siegfried, Mark D. Greenhalgh, Rifahath M. Neyyappadath, and Andrew D. Smith. "Isothiourea-Catalysed Sequential Kinetic Resolution of Acyclic (±)-1,2-Diols." Synlett 30, no. 13 (July 10, 2019): 1555–60. http://dx.doi.org/10.1055/s-0037-1610721.

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The isothiourea-catalysed acylative kinetic resolution of a range of acyclic (±)-1,2-diols using 1 mol% of catalyst under operationally simple conditions is reported. Significantly, the bifunctional nature of (±)-1,2-diols was exploited in a sequential double kinetic resolution, in which both kinetic resolutions operate synergistically to provide access to highly enantioenriched products. The principles that underpin this process are discussed, and selectivity factors for the individual kinetic resolution steps are reported in a model system.

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46

Fenech, Sara, Ruth M. Doherty, Clare Heaviside, Sotiris Vardoulakis, Helen L. Macintyre, and Fiona M. O'Connor. "The influence of model spatial resolution on simulated ozone and fine particulate matter for Europe: implications for health impact assessments." Atmospheric Chemistry and Physics 18, no. 8 (April 25, 2018): 5765–84. http://dx.doi.org/10.5194/acp-18-5765-2018.

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Abstract. We examine the impact of model horizontal resolution on simulated concentrations of surface ozone (O3) and particulate matter less than 2.5 µm in diameter (PM2.5), and the associated health impacts over Europe, using the HadGEM3–UKCA chemistry–climate model to simulate pollutant concentrations at a coarse (∼ 140 km) and a finer (∼ 50 km) resolution. The attributable fraction (AF) of total mortality due to long-term exposure to warm season daily maximum 8 h running mean (MDA8) O3 and annual-average PM2.5 concentrations is then calculated for each European country using pollutant concentrations simulated at each resolution. Our results highlight a seasonal variation in simulated O3 and PM2.5 differences between the two model resolutions in Europe. Compared to the finer resolution results, simulated European O3 concentrations at the coarse resolution are higher on average in winter and spring (∼ 10 and ∼ 6 %, respectively). In contrast, simulated O3 concentrations at the coarse resolution are lower in summer and autumn (∼ −1 and ∼ −4 %, respectively). These differences may be partly explained by differences in nitrogen dioxide (NO2) concentrations simulated at the two resolutions. Compared to O3, we find the opposite seasonality in simulated PM2.5 differences between the two resolutions. In winter and spring, simulated PM2.5 concentrations are lower at the coarse compared to the finer resolution (∼ −8 and ∼ −6 %, respectively) but higher in summer and autumn (∼ 29 and ∼ 8 %, respectively). Simulated PM2.5 values are also mostly related to differences in convective rainfall between the two resolutions for all seasons. These differences between the two resolutions exhibit clear spatial patterns for both pollutants that vary by season, and exert a strong influence on country to country variations in estimated AF for the two resolutions. Warm season MDA8 O3 levels are higher in most of southern Europe, but lower in areas of northern and eastern Europe when simulated at the coarse resolution compared to the finer resolution. Annual-average PM2.5 concentrations are higher across most of northern and eastern Europe but lower over parts of southwest Europe at the coarse compared to the finer resolution. Across Europe, differences in the AF associated with long-term exposure to population-weighted MDA8 O3 range between −0.9 and +2.6 % (largest positive differences in southern Europe), while differences in the AF associated with long-term exposure to population-weighted annual mean PM2.5 range from −4.7 to +2.8 % (largest positive differences in eastern Europe) of the total mortality. Therefore this study, with its unique focus on Europe, demonstrates that health impact assessments calculated using modelled pollutant concentrations, are sensitive to a change in model resolution by up to ∼ ±5 % of the total mortality across Europe.

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47

Strahan, S. E., and B. C. Polansky. "Meteorological implementation issues in chemistry and transport models." Atmospheric Chemistry and Physics 6, no. 10 (July 12, 2006): 2895–910. http://dx.doi.org/10.5194/acp-6-2895-2006.

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Abstract. Offline chemistry and transport models (CTMs) are versatile tools for studying composition and climate issues requiring multi-decadal simulations. They are computationally fast compared to coupled chemistry climate models, making them well-suited for integrating sensitivity experiments necessary for understanding model performance and interpreting results. The archived meteorological fields used by CTMs can be implemented with lower horizontal or vertical resolution than the original meteorological fields in order to shorten integration time, but the effects of these shortcuts on transport processes must be understood if the CTM is to have credibility. In this paper we present a series of sensitivity experiments on a CTM using the Lin and Rood advection scheme, each differing from another by a single feature of the wind field implementation. Transport effects arising from changes in resolution and model lid height are evaluated using process-oriented diagnostics that intercompare CH4, O3, and age tracer carried in the simulations. Some of the diagnostics used are derived from observations and are shown as a reality check for the model. Processes evaluated include tropical ascent, tropical-midlatitude exchange, poleward circulation in the upper stratosphere, and the development of the Antarctic vortex. We find that faithful representation of stratospheric transport in this CTM is possible with a full mesosphere, ~1 km resolution in the lower stratosphere, and relatively low vertical resolution (>4 km spacing) in the middle stratosphere and above, but lowering the lid from the upper to lower mesosphere leads to less realistic constituent distributions in the upper stratosphere. Ultimately, this affects the polar lower stratosphere, but the effects are greater for the Antarctic than the Arctic. The fidelity of lower stratospheric transport requires realistic tropical and high latitude mixing barriers which are produced at 2°×2.5°, but not lower resolution. At 2°×2.5° resolution, the CTM produces a vortex capable of isolating perturbed chemistry (e.g. high Cly and low NOy) required for simulating polar ozone loss.

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Sakhibullin, N. A. "Model Atmospheres and Chemistry." Symposium - International Astronomical Union 145 (1991): 49–61. http://dx.doi.org/10.1017/s0074180900227253.

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The limitations imposed on the accuracy of the abundance determination by the current status of the stellar atmosphere models are discussed. It is shown that the very high S/N ratio and resolution in spectroscopic observations require the new additional steps in stellar atmosphere modeling and in the line formation theory.

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Howe, J. M., and R. Gronsky. "Atomic chemistry by HREM and image simulations?" Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 828–29. http://dx.doi.org/10.1017/s0424820100145480.

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The technique of high-resolution electron microscopy (HREM) is invaluable to the materials scientist because it allows examination of microstructural features at levels of resolution that are unobtainable by most other methods. Although the structural information which can be determined by HREM and accompanying image simulations has been well documented in the literature, there have only been a few cases where this technique has been used to reveal the chemistry of individual columns or planes of atoms, as occur in segregated and ordered materials.

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Duponchel, Ludovic, Peyman Milanfar, Cyril Ruckebusch, and Jean-Pierre Huvenne. "Super-resolution and Raman chemical imaging: From multiple low resolution images to a high resolution image." Analytica Chimica Acta 607, no. 2 (January 2008): 168–75. http://dx.doi.org/10.1016/j.aca.2007.12.004.

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