Global biogenic volatile organic compound emissions in the ORCHIDEE and MEGAN models and sensitivity to key parameters

International audienceA new version of the biogenic volatile organic compounds (BVOCs) emission scheme has been developed in the global vegetation model ORCHIDEE (Organizing Carbon and Hydrology in Dynamic EcosystEm), which includes an extended list of biogenic emitted compounds, updated emission factors (EFs), a dependency on light for almost all compounds and a multi-layer radiation scheme. Over the 2000–2009 period, using this model, we estimate mean global emissions of 465 Tg C yr−1 for isoprene, 107.5 Tg C yr−1 for monoterpenes, 38 Tg C yr−1 for methanol, 25 Tg C yr−1 for acetone and 24 Tg C yr−1 for sesquiterpenes. The model results are compared to state-of-the-art emission budgets, showing that the ORCHIDEE emissions are within the range of published estimates. ORCHIDEE BVOC emissions are compared to the estimates of the Model of Emissions of Gases and Aerosols from Nature (MEGAN), which is largely used throughout the biogenic emissions and atmospheric chemistry community. Our results show that global emission budgets of the two models are, in general, in good agreement. ORCHIDEE emissions are 8 % higher for isoprene, 8 % lower for methanol, 17 % higher for acetone, 18 % higher for monoterpenes and 39 % higher for sesquiterpenes, compared to the MEGAN estimates. At the regional scale, the largest differences between ORCHIDEE and MEGAN are highlighted for isoprene in northern temperate regions, where ORCHIDEE emissions are higher by 21 Tg C yr−1, and for monoterpenes, where they are higher by 4.4 and 10.2 Tg C yr−1 in northern and southern tropical regions compared to MEGAN. The geographical differences between the two models are mainly associated with different EF and plant functional type (PFT) distributions, while differences in the seasonal cycle are mostly driven by differences in the leaf area index (LAI). Sensitivity tests are carried out for both models to explore the response to key variables or parameters such as LAI and light-dependent fraction (LDF). The ORCHIDEE and MEGAN emissions are differently affected by LAI changes, with a response highly depending on the compound considered. Scaling the LAI by a factor of 0.5 and 1.5 changes the isoprene global emission by −21 and +8 % for ORCHIDEE and −15 and +7 % for MEGAN, and affects the global emissions of monoterpenes by −43 and +40 % for ORCHIDEE and −11 and +3 % for MEGAN. Performing a further sensitivity test, forcing ORCHIDEE with the MODIS LAI, confirms the high sensitivity of the ORCHIDEE emission module to LAI variation. We find that MEGAN is more sensitive to variation in the LDF parameter than ORCHIDEE. Our results highlight the importance and the need to further explore the BVOC emission estimate variability and the potential for using models to investigate the estimated uncertainties

An extreme-scale implicit solver for complex PDEs: highly heterogeneous flow in earth's mantle

Mantle convection is the fundamental physical process within earth's interior responsible for the thermal and geological evolution of the planet, including plate tectonics. The mantle is modeled as a viscous, incompressible, non-Newtonian fluid. The wide range of spatial scales, extreme variability and anisotropy in material properties, and severely nonlinear rheology have made global mantle convection modeling with realistic parameters prohibitive. Here we present a new implicit solver that exhibits optimal algorithmic performance and is capable of extreme scaling for hard PDE problems, such as mantle convection. To maximize accuracy and minimize runtime, the solver incorporates a number of advances, including aggressive multi-octree adaptivity, mixed continuous-discontinuous discretization, arbitrarily-high-order accuracy, hybrid spectral/geometric/algebraic multigrid, and novel Schur-complement preconditioning. These features present enormous challenges for extreme scalability. We demonstrate that---contrary to conventional wisdom---algorithmically optimal implicit solvers can be designed that scale out to 1.5 million cores for severely nonlinear, ill-conditioned, heterogeneous, and anisotropic PDEs

Synthesis of New Formyl Halo N-methylimidazole Derivatives

Bromo-formyl imidazoles 16-20 have been prepared by three different ways. The first consisted of conversion of bromo or iodo imidazoles 1-6 into diethyl acetals 13-15, and subsequent hydrolysis into formyl derivatives 7-9. In the second, bromination of. formyl imidazoles with NBS afforded compounds 16-18 in 45-70°/o yield. The third method used direct formylation of bromo imidazoles 10-12 with n-BuLi/DMF reagent into compounds 16, 19, and 20

Bayesian Poroelastic Aquifer Characterization from InSAR Surface Deformation Data. Part I: Maximum A Posteriori Estimate

Characterizing the properties of groundwater aquifers is essential for predicting aquifer response and managing groundwater resources. In this work, we develop a high-dimensional scalable Bayesian inversion framework governed by a three-dimensional quasi-static linear poroelastic model to characterize lateral permeability variations in groundwater aquifers. We determine the maximum a posteriori (MAP) point of the posterior permeability distribution from centimeter-level surface deformation measurements obtained from Interferometric Synthetic Aperture Radar (InSAR). The scalability of our method to high parameter dimension is achieved through the use of adjoint-based derivatives, inexact Newton methods to determine the MAP point, and a Mat\'ern class sparse prior precision operator. Together, these guarantee that the MAP point is found at a cost, measured in number of forward/adjoint poroelasticity solves, that is independent of the parameter dimension. We apply our methodology to a test case for a municipal well in Mesquite, Nevada, in which InSAR and GPS surface deformation data are available. We solve problems with up to 320,824 state variable degrees of freedom (DOFs) and 16,896 parameter DOFs. A consistent treatment of noise level is employed so that the aquifer characterization result does not depend on the pixel spacing of surface deformation data. Our results show that the use of InSAR data significantly improves characterization of lateral aquifer heterogeneity, and the InSAR-based aquifer characterization recovers complex lateral displacement trends observed by independent daily GPS measurements

Computer-aided approaches reveal trihydroxychroman and pyrazolone derivatives as potential inhibitors of SARS-CoV-2 virus main protease

COVID-19 was declared a pandemic by the World Health Organization (WHO) in March 2020. The disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this study is to target the SARS-CoV-2 virus main protease (Mpro) via structure-based virtual screening. Consequently, > 580,000 ligands were processed via several filtration and docking steps, then the top 21 compounds were analysed extensively via MM-GBSA scoring and molecular dynamic simulations. Interestingly, the top compounds showed favorable binding energies and binding patterns to the protease enzyme, forming interactions with several key residues. Trihydroxychroman and pyrazolone derivatives, SN02 and SN18 ligands, exhibited very promising binding modes along with the best MM-GBSA scoring of –40.9 and –41.2 kcal mol–1, resp. Hence, MD simulations for the ligand-protein complexes of SN02 and SN18 affirmed the previously attained results of the potential inhibition activity of these two ligands. These potential inhibitors can be the starting point for further studies to pave way for the discovery of new antiviral drugs for SARS-CoV-2

Computer-aided discovery of antimicrobial agents as potential enoyl acyl carrier protein reductase inhibitors

Purpose: To perform a virtual screening for a set of drug-like ligand library against the Staphylococcus aureus enoyl acyl carrier protein reductase, saFabI.Methods: The virtual screening was conducted based on a previously validated pharmacophoreconstrained docking. Consequently, the top list obtained was filtered using visual inspection where forty compounds were selected for experimental testing using disk-diffusion test and broth dilution method. The hits obtained were checked for their toxicity against human fibroblasts cell lines.Results: Three compounds were active against Staphylococcus aureus and other tested gram-positive bacteria. However, no significant inhibitory activity (p < 0.05) was detected against Escherichia coli or Candida albicans. The minimum inhibitory concentration (MIC) values for the most active compounds were identified using the broth dilution method; all of them exhibited inhibitory activity within micromolar range.The docking results showed that the hits obtained exhibited a small size with a nice binding mode to saFabI enzyme, forming the important interactions with the key residues. Furthermore, the best three hits demonstrated good safety profile as they did not show any significant toxicity against human fibroblast cell line.Conclusion: Overall, the newly discovered hits can act as a good starting point in the future for the development of safe and potent antibacterial agents.Keywords: Enoyl acyl carrier protein reductase, saFabI, Antibacterial agents, Docking, Constraint, Virtual screening Tropical Journal of Pharmaceutica

Support for UNRWA's survival

The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland

SYNTHESIS OF AMINO ACETYLENIC BENZOPHENONE DERIVATIVES AS H3-ANTAGONISTS

Objective: To synthesize new amino acetylenic benzophenone derivatives with significant H3-antagonist's activity.Methods: Amino acetylenic benzophenone derivatives were synthesized from the reaction of 2-hydroxybenzophenone with 3-bromoprop-1-in to generate 2-(prop-2-yn-1-yloxy)-1,3-benzophenone (AZ-1). A mixture of 2-(prop-2-yn-1-yloxy)-1,3-benzophenone, paraformaldehyde, cyclic amine, cuprous chloride (catalytic amount) in peroxide free dioane through Mannich reaction yielded the designed amino acetylenic benzophenone derivatives (AZ-2-7).Results: The IR, H1-NMR, 13C NMR, and elemental analysis were consistent with the assigned structures. The designers of these compounds as H3-antagonists were based on the nationalization of the important criteria that provide effective inhibitory binding with H3-receptor. Molecular docking results of compounds (AZ-2-7) showed a good H3-receptor antagonistic activity relative to thioperamide of-6 (kcal/mol) especially AZ-2 which has-8.6 (kcal/mol).Conclusion: Docking results provide a good lead to designing more effective H3 antagonists in managing many CNS diseases like Alzheimer, epilepsy, depression, schizophrenia and many others

DESIGN, SYNTHESIS AND BIOLOGICAL SCREENING OF AMINOACETYLENIC TETRAHYDROPHTHALIMIDE ANALOGUES AS NOVEL CYCLOOXYGENASE (COX) INHIBITORS

Objective: To design and synthesise a new amino acetylenic tetrahydro phthalimide derivative and investigate their selective inhibitory activity to COXs.Methods: Aminoacetylenic tetrahydro phthalimide derivatives were synthesised by alkylation of tetrahydro phthalimide with propargyl bromide afforded 2-(prop-2-yn-1-yl)-2,3,3a,4,7,7a-hexahydro-1H-isoindole-1,3-dione. The alkylated tetrahydro phthalimide was subjected to Mannich reaction afforded the desired amino acetylenic tetra phthalimide derivatives (AZ 1-6). The elemental analysis was indicated by the EuroEA elemental analyzer and biological characterization was via IR, 1H-NMR, [13]C-NMR, DSC was determined with the aid of Bruker FT-IR and Varian 300 MHz spectrometer and DMSO-d6 as a solvent, molecular docking was done using the Autodock Tool software (version 4.2). ChemBioDraw was used in the drawing of our schemes.Results: The IR, 1H-NMR, 13C-NMR, DSC and elemental analysis were consistent with the assigned structures. The designers of the compounds as COXs inhibitor activity were based on the nationalisation of the important criteria that provide effective inhibitory binding with COXs–receptor. The results indicated that the synthesised compounds (AZ1-6) showed a close similarity in the binding affinity to both COXs and may be more specific to COX-1. AZ-5 showed the highest % of inhibition for COX-1 even better than aspirin. Which may suggest that the aryl group is required for COX-2 inhibition.Conclusion: For the first time, we indicate the requirement of aromaticity in COX-2 structural inhibitory activity.Â