Optimal Multi-TDMA Scheduling in Ring Topology Networks

A scheduling algorithm will be proposed for wireless ring topology networks, utilizing time division multiple access (TDMA) with possible simultaneous operation of nodes. The proposed algorithm finds the optimal schedule to minimize the turnaround time for messages in the network. The properties of the algorithm are mathematically analyzed and proven, and practical test results are also provided

DETERMINATION OF THE ACTIVE INGREDIENT (5-ETHYL-2'-DEOXYURIDINE) OF THE OINTMENT 'REVIDUR' BY UV AND NIR SPECTROSCOPY

UV spectrophotometric and NIR spectroscopic methods were developed for determining the active ingredient (5-ethyl-2'-deoxy-uridine) in the antiviral ointment (Revidur). UV spectrophotometric measurements were carried out at 263 nm with solution of the ointment in absolute ethanol prepared by ultrasonication. Calibration solutions contained the matrix. The standard error of the method was 0.016%, the correlation coefficient of the calibration curve was 0.999 in the range 0.25 to 2.5% drug content. Two NIR methods are described in the present work. In one of the methods, NIR reflectance spectra were taken of solutions and concentration determinations were carried out based on the second derivative of the spectra at 1166 nm. The correlation coefficient was equal to that calculated for the UV method, and the standard calibration error was slightly higher, 0.05%. The advantage of the method is its quickness if calibration data are available. The simpler method developed seems to be suitable for the determination of the drug directly in the ointment without any pretreatment. In the is method, the second derivative of the NIR reflectance spectra measured at 2466 and 1528 nm are used. How- ever, due to inhomogeneity problems with the calibration samples resulting in a standard calibration error one order of magnitude higher than that for the solution technique, we consider our results with the direct method to by only preliminary onesand intend to continue our studies

Percolation Driven Floodingf or Energy Efficient Routing in Dense Sensor Networks, Journal of Telecommunications and Information Technology, 2009, nr 2

Simple flooding algorithms are widely used in ad hoc sensor networks either for information dissemination or as building blocks of more sophisticated routing protocols. In this paper a percolation driven probabilistic flooding algorithm is proposed, which provides large message delivery ratio with small number of sent messages, compared to traditional flooding. To control the number of sent messages the proposed algorithm uses locally available information only, thus induces negligible overhead on network traffic. The performance of the algorithm is analyzed and the theoretical resultsare verified through simulation examples

Design of a VLC-based Beaconing Infrastructure for Indoor Localization Applications

In this paper the design of an LED-based beaconing infrastructure is introduced, which can be utilized in indoor localization systems. The LED beacons, which may be part of the existing lighting infrastructure, are blinking with high frequency invisible for human eyes, while the detectors are regular cameras. Since the sampling frequency of the cameras is much lower than the blinking frequency, the detection is based on a coding system, which tolerates the undersampling of the signal. The performance of the proposed system is analyzed and a possible application is introduced

Semi-Automatic Detection and Tracking of Growing Mushrooms on Image Sequences

The efficient management of autonomous mushroom production plants requires the model of growth rate of mushrooms. Photos of the plants are used as input for the growth models, which then predict the development of individual mushrooms. Recently machine learning techniques have been successfully applied to create such models. For the machine learning systems, however, large number of training samples are required. The training samples include photos of the plant and also ground truth markers indicating the position and size of the mushrooms on the photo. In this paper an image processing system is introduced, which is able to create good quality ground truth from sequences of images of the plant. The proposed system can automatically detect the mushroom positions and sizes on each of the pictures, but also allows user intervention to minimize the number of detection errors

1,6-Conjugate Additions of Carbon Nucleophiles to 2-[(1E,3E)-4-Arylbuta-1,3-dien-1-yl]-4H-chromen-4-ones

KGaA, Weinheim The 1,6-conjugate addition of nitromethane to 2-[(1E,3E)-4-arylbuta-1,3-dien-1-yl]-4H-chromen-4-ones was accomplished and led mainly to the corresponding β-(nitromethyl)chromones. (E)-5′-(Nitromethyl)-3′-styryl-[1,1′-biphenyl] -2-ol and 3′-aryl-2′-nitro-5′-(nitromethyl)spiro[chromane-2,1′-cyclohexan]-4-one derivatives were also isolated as minor products from tandem processes, which result from the addition of a second molecule of nitromethane. The nucleophile scope was investigated with malononitrile, acetylacetone, ethyl cyanoacetate, and diethyl malonate, which gave the expected 1,6-addition products; in the last case, it was also possible to isolate a minor product formed through a 1,8-/1,6-addition sequence. Computational calculations provided a rationale for the experimental reactivity of carbon nucleophiles with 2-[(1E,3E)-4-arylbuta-1,3-dien-1-yl] -4H-chromen-4-ones. The further functionalization of some adducts allowed the preparation of new nitrogen-containing heterocyclic compounds, such as new styrylpyrrolidines and new pyrazole and bis(pyrazole) derivatives.Thanks are due to the University of Aveiro and Fundação para a Ciência e a Tecnologia (FCT)/Ministerio de Educación y Ciencia (MEC) for the financial support of the QOPNA research unit (FCT UID/QUI/00062/2013) through national funds and, where applicable, cofinanced by Fundo Europeu de Desenvolvimento Regional (FEDER) within the PT2020 Partnership Agreement, and to the Portuguese NMR Network as well as the Instituto Politécnico de Bragança. H. M. T. A. is grateful to Fundação para a Ciência e a Tecnologia (FCT) for his PhD grant (SFRH/BD/86277/ 2012).info:eu-repo/semantics/publishedVersio

In situ preparation of a multifunctional chiral hybrid organic-inorganic catalyst for asymmetric multicomponent reactions

[EN] A chiral mesoporous organosilica material incorporating a urea based-cinchona derivative and propylamine groups was prepared by a co-condensation method. The multisite solid catalyst efficiently promoted the asymmetric multicomponent reaction of aldehydes, malonates and nitromethane.This work was supported by the Spanish Government (Consolider Ingenio 2010-MULTICAT (CSD2009-00050) and MAT2011-29020-C02-01). P.G.-G. is grateful for a JAE-DOC contract from CSIC co-funded by the ESF. The Severo Ochoa program is thankfully acknowledged.García García, P.; Zagdoun, A.; Coperet, C.; Lesage, A.; Díaz Morales, UM.; Corma Canós, A. (2013). In situ preparation of a multifunctional chiral hybrid organic-inorganic catalyst for asymmetric multicomponent reactions. Chemical Science. 4(5):2006-2012. https://doi.org/10.1039/C3SC22310HS2006201245José Climent, M., Corma, A., & Iborra, S. (2012). Homogeneous and heterogeneous catalysts for multicomponent reactions. 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Brønsted-Acid-Catalyzed Asymmetric Multicomponent Reactions for the Facile Synthesis of Highly Enantioenriched Structurally Diverse Nitrogenous Heterocycles. Accounts of Chemical Research, 44(11), 1156-1171. doi:10.1021/ar2000343Huang, Y., Walji, A. M., Larsen, C. H., & MacMillan, D. W. C. (2005). Enantioselective Organo-Cascade Catalysis. Journal of the American Chemical Society, 127(43), 15051-15053. doi:10.1021/ja055545dEnders, D., Hüttl, M. R. M., Grondal, C., & Raabe, G. (2006). Control of four stereocentres in a triple cascade organocatalytic reaction. Nature, 441(7095), 861-863. doi:10.1038/nature04820Galzerano, P., Pesciaioli, F., Mazzanti, A., Bartoli, G., & Melchiorre, P. (2009). Asymmetric Organocatalytic Cascade Reactions with α-Substituted α,β-Unsaturated Aldehydes. Angewandte Chemie International Edition, 48(42), 7892-7894. doi:10.1002/anie.200903803Ramachary, D. B., Chowdari, N. S., & Barbas, C. F. (2003). Organocatalytic Asymmetric Domino Knoevenagel/Diels–Alder Reactions: A Bioorganic Approach to the Diastereospecific and Enantioselective Construction of Highly Substituted Spiro[5,5]undecane-1,5,9-triones. Angewandte Chemie International Edition, 42(35), 4233-4237. doi:10.1002/anie.200351916Ramachary, D. B., Anebouselvy, K., Chowdari, N. S., & Barbas, C. F. (2004). Direct Organocatalytic Asymmetric Heterodomino Reactions:  The Knoevenagel/Diels−Alder/Epimerization Sequence for the Highly Diastereoselective Synthesis of Symmetrical and Nonsymmetrical Synthons of Benzoannelated Centropolyquinanes. The Journal of Organic Chemistry, 69(18), 5838-5849. doi:10.1021/jo049581rRamachary, D. B., & Barbas, C. F. (2004). Towards Organo-Click Chemistry: Development of Organocatalytic Multicomponent Reactions Through Combinations of Aldol, Wittig, Knoevenagel, Michael, Diels-Alder and Huisgen Cycloaddition Reactions. 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(2006). Polystyrene-Supported Hydroxyproline:  An Insoluble, Recyclable Organocatalyst for the Asymmetric Aldol Reaction in Water. Organic Letters, 8(20), 4653-4655. doi:10.1021/ol061964jZamboulis, A., Rahier, N. J., Gehringer, M., Cattoën, X., Niel, G., Bied, C., … Man, M. W. C. (2009). Silica-supported l-proline organocatalysts for asymmetric aldolisation. Tetrahedron: Asymmetry, 20(24), 2880-2885. doi:10.1016/j.tetasy.2009.11.024Fan, X., Sayalero, S., & Pericàs, M. A. (2012). Asymmetric α-Amination of Aldehydes Catalyzed by PS-Diphenylprolinol Silyl Ethers: Remediation of Catalyst Deactivation for Continuous Flow Operation. Advanced Synthesis & Catalysis, 354(16), 2971-2976. doi:10.1002/adsc.201200887Wang, C. A., Zhang, Z. K., Yue, T., Sun, Y. L., Wang, L., Wang, W. D., … Wang, W. (2012). «Bottom-Up» Embedding of the Jørgensen-Hayashi Catalyst into a Chiral Porous Polymer for Highly Efficient Heterogeneous Asymmetric Organocatalysis. Chemistry - A European Journal, 18(22), 6718-6723. doi:10.1002/chem.201200753Riente, P., Yadav, J., & Pericàs, M. A. (2012). A Click Strategy for the Immobilization of MacMillan Organocatalysts onto Polymers and Magnetic Nanoparticles. Organic Letters, 14(14), 3668-3671. doi:10.1021/ol301515dShi, J. Y., Wang, C. A., Li, Z. J., Wang, Q., Zhang, Y., & Wang, W. (2011). Heterogeneous Organocatalysis at Work: Functionalization of Hollow Periodic Mesoporous Organosilica Spheres with MacMillan Catalyst. Chemistry – A European Journal, 17(22), 6206-6213. doi:10.1002/chem.201100072Bleschke, C., Schmidt, J., Kundu, D. S., Blechert, S., & Thomas, A. (2011). A Chiral Microporous Polymer Network as Asymmetric Heterogeneous Organocatalyst. Advanced Synthesis & Catalysis, 353(17), 3101-3106. doi:10.1002/adsc.201100674Rueping, M., Sugiono, E., Steck, A., & Theissmann, T. (2010). Synthesis and Application of Polymer-Supported Chiral Brønsted Acid Organocatalysts. Advanced Synthesis & Catalysis, 352(2-3), 281-287. doi:10.1002/adsc.200900746Kasaplar, P., Riente, P., Hartmann, C., & Pericàs, M. A. (2012). A Polystyrene-Supported, Highly Recyclable Squaramide Organocatalyst for the Enantioselective Michael Addition of 1,3-Dicarbonyl Compounds to β-Nitrostyrenes. Advanced Synthesis & Catalysis, 354(16), 2905-2910. doi:10.1002/adsc.201200526Wang, W., Ma, X., Wan, J., Cao, J., & Tang, Q. (2012). Preparation and confinement effect of a heterogeneous 9-amino-9-deoxy-epi-cinchonidine organocatalyst for asymmetric aldol addition in aqueous medium. Dalton Transactions, 41(18), 5715. doi:10.1039/c2dt12390hCancogni, D., Mandoli, A., Jumde, R. P., & Pini, D. (2012). Silicone-Supported Cinchona Alkaloid Derivatives as Insoluble Organocatalysts in the Enantioselective Dimerization of Ketenes. European Journal of Organic Chemistry, 2012(7), 1336-1345. doi:10.1002/ejoc.201101320Jumde, R. P., Mandoli, A., De Lorenzi, F., Pini, D., & Salvadori, P. (2010). Simple Preparation of Dimeric Cinchona Alkaloid Derivatives on Polystyrene Supports and a Highly Enantioselective Catalytic Heterogeneous Dimerization of Ketenes. Advanced Synthesis & Catalysis, 352(9), 1434-1440. doi:10.1002/adsc.201000165Youk, S. H., Oh, S. H., Rho, H. S., Lee, J. E., Lee, J. W., & Song, C. E. (2009). A polymer-supported Cinchona-based bifunctional sulfonamide catalyst: a highly enantioselective, recyclable heterogeneous organocatalyst. Chemical Communications, (16), 2220. doi:10.1039/b821483bConnon, S. J. (2006). Organocatalysis Mediated by (Thio)urea Derivatives. Chemistry - A European Journal, 12(21), 5418-5427. doi:10.1002/chem.200501076Siau, W.-Y., & Wang, J. (2011). Asymmetric organocatalytic reactions by bifunctional amine-thioureas. Catalysis Science & Technology, 1(8), 1298. doi:10.1039/c1cy00271fMiyabe, H., & Takemoto, Y. (2008). Discovery and Application of Asymmetric Reaction by Multi-Functional Thioureas. Bulletin of the Chemical Society of Japan, 81(7), 785-795. doi:10.1246/bcsj.81.785Yu, P., He, J., & Guo, C. (2008). 9-Thiourea Cinchona alkaloid supported on mesoporous silica as a highly enantioselective, recyclable heterogeneous asymmetric catalyst. Chemical Communications, (20), 2355. doi:10.1039/b800640gGleeson, O., Davies, G.-L., Peschiulli, A., Tekoriute, R., Gun’ko, Y. K., & Connon, S. J. (2011). The immobilisation of chiral organocatalysts on magnetic nanoparticles: the support particle cannot always be considered inert. Organic & Biomolecular Chemistry, 9(22), 7929. doi:10.1039/c1ob06110kVakulya, B., Varga, S., Csámpai, A., & Soós, T. (2005). Highly Enantioselective Conjugate Addition of Nitromethane to Chalcones Using Bifunctional Cinchona Organocatalysts. Organic Letters, 7(10), 1967-1969. doi:10.1021/ol050431sChen, W., Du, W., Duan, Y.-Z., Wu, Y., Yang, S.-Y., & Chen, Y.-C. (2007). Enantioselective 1,3-Dipolar Cycloaddition of Cyclic Enones Catalyzed by Multifunctional Primary Amines: Beneficial Effects of Hydrogen Bonding. Angewandte Chemie International Edition, 46(40), 7667-7670. doi:10.1002/anie.200702618Díaz, U., García, T., Velty, A., & Corma, A. (2009). Hybrid organic–inorganic catalytic porous materials synthesized at neutral pH in absence of structural directing agents. Journal of Materials Chemistry, 19(33), 5970. doi:10.1039/b906821jLakshmi Kantam, M., & Sreekanth, P. (1999). Catalysis Letters, 57(4), 227-231. doi:10.1023/a:1019012019131Sartori, G. (2004). Catalytic activity of aminopropyl xerogels in the selective synthesis of (E)-nitrostyrenes from nitroalkanes and aromatic aldehydes. Journal of Catalysis, 222(2), 410-418. doi:10.1016/j.jcat.2003.11.016Wang, Q., & Shantz, D. F. (2010). Nitroaldol reactions catalyzed by amine-MCM-41 hybrids. Journal of Catalysis, 271(2), 170-177. doi:10.1016/j.jcat.2010.01.010Motokura, K., Tada, M., & Iwasawa, Y. (2008). Cooperative Catalysis of Primary and Tertiary Amines Immobilized on Oxide Surfaces for One-Pot CC Bond Forming Reactions. Angewandte Chemie International Edition, 47(48), 9230-9235. doi:10.1002/anie.200802515SOLDI, L., FERSTL, W., LOEBBECKE, S., MAGGI, R., MALMASSARI, C., SARTORI, G., & YADA, S. (2008). Use of immobilized organic base catalysts for continuous-flow fine chemical synthesis. Journal of Catalysis, 258(2), 289-295. doi:10.1016/j.jcat.2008.07.005Ye, J., Dixon, D. J., & Hynes, P. S. (2005). Enantioselective organocatalytic Michael addition of malonate esters to nitro olefins using bifunctional cinchonine derivatives. Chemical Communications, (35), 4481. doi:10.1039/b508833jMcCooey, S. H., & Connon, S. J. (2005). Urea- and Thiourea-Substituted Cinchona Alkaloid Derivatives as Highly Efficient Bifunctional Organocatalysts for the Asymmetric Addition of Malonate to Nitroalkenes: Inversion of Configuration at C9 Dramatically Improves Catalyst Performance. Angewandte Chemie International Edition, 44(39), 6367-6370. doi:10.1002/anie.200501721Hynes, P. S., Stupple, P. A., & Dixon, D. J. (2008). Organocatalytic Asymmetric Total Synthesis of (R)-Rolipram and Formal Synthesis of (3S,4R)-Paroxetine. Organic Letters, 10(7), 1389-1391. doi:10.1021/ol800108uOkino, T., Hoashi, Y., Furukawa, T., Xu, X., & Takemoto, Y. (2005). Enantio- and Diastereoselective Michael Reaction of 1,3-Dicarbonyl Compounds to Nitroolefins Catalyzed by a Bifunctional Thiourea. Journal of the American Chemical Society, 127(1), 119-125. doi:10.1021/ja044370pXu, F., Corley, E., Zacuto, M., Conlon, D. A., Pipik, B., Humphrey, G., … Tschaen, D. (2010). Asymmetric Synthesis of a Potent, Aminopiperidine-Fused Imidazopyridine Dipeptidyl Peptidase IV Inhibitor. The Journal of Organic Chemistry, 75(5), 1343-1353. doi:10.1021/jo902573qLiu, J., Wang, X., Ge, Z., Sun, Q., Cheng, T., & Li, R. (2011). Solvent-free organocatalytic Michael addition of diethyl malonate to nitroalkenes: the practical synthesis of Pregabalin and γ-nitrobutyric acid derivatives. Tetrahedron, 67(3), 636-640. doi:10.1016/j.tet.2010.11.053Elsner, P., Jiang, H., Nielsen, J. B., Pasi, F., & Jørgensen, K. A. (2008). A modular and organocatalytic approach to γ-butyrolactone autoregulators from Streptomycetes. Chemical Communications, (44), 5827. doi:10.1039/b812698dPoe, S. L., Kobašlija, M., & McQuade, D. T. (2006). Microcapsule Enabled Multicatalyst System. Journal of the American Chemical Society, 128(49), 15586-15587. doi:10.1021/ja066476lPoe, S. L., Kobašlija, M., & McQuade, D. T. (2007). Mechanism and Application of a Microcapsule Enabled Multicatalyst Reaction. Journal of the American Chemical Society, 129(29), 9216-9221. doi:10.1021/ja071706

Organocatalytic Enantioselective Strecker Reaction with Seven-Membered Cyclic Imines

[EN] A highly enantioselective Strecker reaction with dibenzo[b,f][1,4]oxazepines has been described using a dihydroquinine-derived thiourea as organocatalyst. The reaction affords chiral 10,11-dihydrodibenzo[b,f][1,4] oxazepine 11-carbonitrile derivatives in excellent yields (up to 99%) and excellent enantioselectivities (up to 98%) under mild reaction conditions.Financial support from the Agencia Estatal de Investigacion (Spanish Government) and Fondo Europeo de Desarrollo Regional (FEDER, European Union) (CTQ2017-84900-P) is acknowledged. C. V. thanks the Spanish Government for a Ramon y Cajal contract (RyC-2016-20187). Access to NMR, MS and X-ray facilities from the Servei central de suport a la investigacio experimental (SCSIE)-UV is also acknowledged.Lluna Galán, C.; Blay, G.; Fernández, I.; Muñoz Roca, MDC.; Pedro, JR.; Vila, C. (2018). Organocatalytic Enantioselective Strecker Reaction with Seven-Membered Cyclic Imines. Advanced Synthesis & Catalysis. 360(19):3662-3666. https://doi.org/10.1002/adsc.201800754S366236663601