A Splitting Theorem for Local Cohomology and its Applications

Let $R$ be a commutative Noetherian ring and $M$ a finitely generated $R$-module. We show in this paper that, for an integer $t$, if the local cohomology module $H^{i}_\mathfrak{a}(M)$ with respect to an ideal $\frak a$ is finitely generated for all $i<t$, then $$H^{i}_\mathfrak{a}(M/xM)\cong H^{i}_\mathfrak{a}(M)\oplus H^{i+1}_\mathfrak{a}(M)$for all$\frak a$-filter regular elements$x$containing in a enough large power of$\frak a$and all$i<t-1$. As consequences we obtain generalizations, by very short proofs, of the main results of M. Brodmann and A.L. Faghani (A finiteness result for associated primes of local cohomology modules, Proc. Amer. Math. Soc., 128(2000), 2851-2853) and of H.L. Truong and the first author (Asymptotic behavior of parameter ideals in generalized Cohen-Macaulay module, J. Algebra, 320(2008),158-168).Comment: to appear in J. Algebr

Quantifying organic carbon storage and sources in sediments of Dong Rui mangrove forests, Tien Yen district, Quang Ninh province using carbon stable isotope

The objective of this study is to quantify the organic carbon (OC) storage and its sources in sediments of Dong Rui mangrove forests, Tien Yen district, Quang Ninh province by analyzing TOC (total organic carbon), TN (total nitrogen), C/N ratios, δ13C isotopes and sediment grain sizes. The results showed that the fine-grained sediment fraction (63 µm) ranged from 8.58 to 82.10%; TOC, TN contents, C/N ratios and δ13C values ranged from 0.21 to 10.20%, 0.01 to 0.34%, 15.07 to 46.09 and –27.75 to –25.84‰, respectively. The variation of δ13C and C/N ratios, and the correlation between TOC, TN and the fine-grained sediment fractions indicated that mangrove forests play important roles in OC sequestration and accumulation of fine-grained sediments. The OC storage in sediments varied from 16.7 to 78.3 MgC ha-1 with an average of 57.2 ±14.9 MgC ha-1. Nowadays, the mangrove forest area in Dong Rui is about 2194.1 ha, thus, the total OC in sediment pool up to 45 cm in depth, contained 1.26(±0.3)×105 MgC, equivalent to 4.6(±1.2)×105 Mg CO2. These results demonstrated that the conservation of Dong Rui mangrove forest not only provides opportunities for coastal protection and disaster mitigation and other provision values, but also enhancing carbon sequestration and offsetting greenhouse gas emissions.References Alongi, D.M., 2011. Carbon payments for mangrove conservation: ecosystem constraints and uncertainties of sequestration potential. Environmental Science Policy 14, 462-470. Alongi, D.M., Sasekumar, A., Chong, V.C., Pfitzner, J., Trott, L.A., Tirendi, F., Dixon, P., Brunskill, G.J., 2004. Sediment accumulation and organic material flux in a managed mangrove ecosystem: estimates of land - ocean - atmosphere exchange in peninsular Malaysia. Marine Geology 208, 383-402. Bouillon, S., Connolly, R., Lee, S., 2008. Organic matter exchange and cycling in mangrove ecosystems: recent insights from stable isotope studies. Journal of Sea Research 59, 44-58. Bouillon, S., Rao, A.V.V.S., Koedam, N., Dahdouh-Guebas, F., Dehairs, F., 2003. Sources of organic carbon in mangrove sediments: variability. Hydrobiologia 495, 33-39. Christensen, B., 1978. Biomass and primary production of Rhizophoraapiculata Bl. in a mangrove in southern Thailand. Aquat Bot 4, 43-52. Donato, D.C., Kauffman, J.B., Murdiyarso, D., Kurnianto, S., Stidham, M., Kanninen, M., 2011. Mangroves among the most carbon - rich forests in the tropics. Nature Geoscience 4, 293-297. Furukawa, K., Wolanski, E., 1996. Sedimentation in mangrove forests. Mangroves Salt Marshes 1, 3-10. Hedges, J.I., Keil, R.G., 1995. Sedimentary organic matter preservation: an assessement and speculative synthesis. Marine Chemistry 49, 137-139. Kauffman, J.B., Donato, D.C., 2012. Protocols for the measurement, monitoring and reporting of structure, biomass and carbon stocks in mangrove forests, 86 pp., Center for International Forest Research, Bogor, Indonesia. Kristensen, E., Bouillon, S., Dittmar, T., Marchand, C., 2008. Organic carbon dynamics in mangrove ecosystems: A review. Aquat Bot 89, 201-209. Lamb, A., Wilson, G., Leng, M., 2006. A review of coastal palaeoclimate and relative sea-level reconstructions using δ13C and C/N ratios in organic material. Earth Science Reviews 75, 29-57. Lovelock, C.E., Ruess, R.W., Feller, I.C., 2011. CO2 efflux from cleared mangrove peat. PLoS ONE 6, 1-4. Ong, J.E., 1993. Mangroves - a carbon source and sink. Chemosphere 27, 1097-1107. Quy, T.D., Tue, N.T., 2011. Spatial distribution of total organic carbon (TOC), total nitrogen (TN), TOC/TN ratio, and stable carbon isotopes value (δ13C) in surface sediments of Tien Yen Bay, northeast Vietnam. Vietnam Journal of Earth Sciences 33, 615-624 (In Vietnamese). Reimers, C.E., Suess, E., 1983. The partitioning of organic carbon fluxes and sedimentary organic matter decomposition rates in the ocean. Marine Chemistry 13, 141-168. Richard, M., Angus, M., Tim, H., 2011. The potential for mangrove carbon projects in Vietnam. SNV REDD+, Hanoi. Schumacher, B.A., 2002. Methods for the determination of total organic carbon in soils and sediments. U.S. Environmental Protection Agency, Washington. Siikamäki, J., Sanchirico, N., Jardine, J., McLaughlin, S., Morris, D.F., 2012. Blue carbon: global options for reducing emissions from the degradation and development of coastal ecosystems. Resources for future, Washington. Spalding, M., Kainuma, M., Collins, L., 2010. World atlas of mangroves. Earthscan from Routledge, London. Tuan, H.V., Quy, T.D., Vuong, N.V., Nhuan, M.T., 2012. Orientation of functional zoning for sustainable use of environment and natural resources in Tien Yen Bay. Vietnam Journal of Earth Sciences 34, 486-494 (In Vietnamese). Tuan, M.S., Hanh, N.T.H., 2009. Carbon accumulation of Kandeliaobovata (Sheue, Liu Yong) plantation in the coastal area of Giao Thuy district, Nam Dinh province. Journal of Biology 31, 57-65 (In Vietnamese). Tue, N.T., Dung, L.V., Nhuan, M.T., Omori, K., 2014. Carbon storage of a tropical mangrove forest in Mui Ca Mau National Park, Vietnam. Catena 121, 119-126. Tue, N.T., Hamaoka, H., Sogabe, A., Quy, T.D., Nhuan, M.T., Omori, K., 2011. The application of δ13C and C/N ratios as indicators of organic carbon sources and paleoenvironmental change of the mangrove ecosystem from Ba Lat Estuary, Red River, Vietnam. Environmental Earth Sciences 64, 1475-1486. Tue, N.T., Ngoc., N.T., Quy, T.D., Hamaok, H., Nhuan, M.T., Omori, K., 2012. A cross-system analysis of sedimentary organic carbon in the mangrove ecosystems of Xuan Thuy National Park, Vietnam. Journal of Sea Research 67, 69-76. Van Santen, P., Augustinus, P., Janssen-Stelder, B., Quartel, S., Tri, N., 2007. Sedimentation in an estuarine mangrove system. Journal of Asian Earth Sciences 29, 566-575

Deployment and validation of an AI system for detecting abnormal chest radiographs in clinical settings

BackgroundThe purpose of this paper is to demonstrate a mechanism for deploying and validating an AI-based system for detecting abnormalities on chest X-ray scans at the Phu Tho General Hospital, Vietnam. We aim to investigate the performance of the system in real-world clinical settings and compare its effectiveness to the in-lab performance.MethodThe AI system was directly integrated into the Hospital's Picture Archiving and Communication System (PACS) after being trained on a fixed annotated dataset from other sources. The system's performance was prospectively measured by matching and comparing the AI results with the radiology reports of 6,285 chest X-ray examinations extracted from the Hospital Information System (HIS) over the last 2 months of 2020. The normal/abnormal status of a radiology report was determined by a set of rules and served as the ground truth.ResultsOur system achieves an F1 score—the harmonic average of the recall and the precision—of 0.653 (95% CI 0.635, 0.671) for detecting any abnormalities on chest X-rays. This corresponds to an accuracy of 79.6%, a sensitivity of 68.6%, and a specificity of 83.9%.ConclusionsComputer-Aided Diagnosis (CAD) systems for chest radiographs using artificial intelligence (AI) have recently shown great potential as a second opinion for radiologists. However, the performances of such systems were mostly evaluated on a fixed dataset in a retrospective manner and, thus, far from the real performances in clinical practice. Despite a significant drop from the in-lab performance, our result establishes a reasonable level of confidence in applying such a system in real-life situations

Molecular docking screening, dynamics simulations, ADMET, and semi-synthesis prediction of flavones and flavonols from the COCONUT database as potent bifunctional neuraminidase inhibitors

Finding new neuraminidase (N) inhibitors to improve anti-influenza treatment is necessary because of the high mutation rates of N protein. Over 3,000 flavones/flavonols and their synthesized products from the COCONUT database were performed in silico docking screening with N1-H274Y-oseltamivir protein (PDB ID: 3CL0). Several derivatives containing nitrogen heterocyclic groups or aromatic rings showed higher anti-neuraminidase potential than that of laninamivir. Especially, the linker groups between the flavone aglycone and nitrogen heterocyclic group created the interactions with the triad of arginine residues Arg118-Arg292-Arg371, which suggested these compounds could become bifunctional inhibitors against the influenza virus strains at the sialic acid binding site and the adjacent 430-cavity position through triad of arginine residues binding. ADMET indicators and the synthesis design strategy of the most suitable compound, ethyl 4-{2-[(5-hydroxy-4-oxo-2-phenyl-4H-chromen-7-yl)oxy]acetyl}piperazine-1-carboxylate, were also successfully predicted and it could be a concerned candidate for further wet-lab synthesis, in vivo and clinical study