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21.
Satyajit Banerjee Atish Datta Chowdhury Subhas Kumar Ghosh 《Mathematics in Computer Science》2008,1(4):673-688
Obtaining a matching in a graph satisfying a certain objective is an important class of graph problems. Matching algorithms
have received attention for several decades. However, while there are efficient algorithms to obtain a maximum weight matching,
not much is known about the maximum weight maximum cardinality, and maximum cardinality maximum weight matching problems for
general graphs. Our contribution in this work is to show that for bounded weight input graphs one can obtain an algorithm
for both maximum weight maximum cardinality (for real weights), and maximum cardinality maximum weight matching (for integer
weights) by modifying the input and running the existing maximum weight matching algorithm. Also, given the current state
of the art in maximum weight matching algorithms, we show that, for bounded weight input graphs, both maximum weight maximum
cardinality, and maximum cardinality maximum weight matching have algorithms of similar complexities to that of maximum weight
matching. Subsequently, we also obtain approximation algorithms for maximum weight maximum cardinality, and maximum cardinality
maximum weight matching.
相似文献
22.
This tutorial review deals with recent advances in the use of phosphine-functionalised polymers in organic synthesis. In the first part of the review, some recent applications of polymer-supported palladium catalysts are reviewed, particularly recyclable catalysts for C-C and C-X bond formation with aryl bromide and chloride substrates. In the second half, novel applications of phosphine-functionalised polymers as reagents, scavengers, organocatalysts and linkers in organic chemistry are presented. Emphasis is placed on the synthesis of biologically active molecules. 相似文献
23.
Philip J. Cox Marcel Jaspars Yashodharan Kumarasamy Lutfun Nahar Satyajit D. Sarker Mohammad Shoeb 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(9):o520-o522
The crystal structure of 9‐(3‐methylbut‐2‐enyloxy)‐7H‐furo[3,2‐g]chromen‐7‐one–4‐methoxy‐9‐(3‐methylbut‐2‐enyloxy)‐7H‐furo[3,2‐g]chromen‐7‐one (0.926/0.074), 0.926C16H14O4·0.074C17H16O5, is characterized by two independent imperatorin molecules in the asymmetric unit, which exhibit different side‐chain conformations. A small amount of phellopterin overlaps with one of the two imperatorin molecules. The supramolecular structure is supported by C—H...O, C—H...π and π–π interactions. 相似文献
24.
Phenol and its derivatives are extremely useful compounds in organic synthesis, medicinal chemistry and material sciences. The synthesis of phenols involving selective construction of the C?O bond at a C?H bond of arenes using transition‐metal catalysis represents the most appealing strategy. Indeed, active research is currently going on for the synthesis of valuable phenolic compounds using a transition‐metal‐catalyzed C?H functionalization strategy. This short review summarizes recent advances on palladium‐catalyzed C?O bond forming reactions that enable direct access to phenolic compounds. These catalytic reactions proceed either via C?H esterification with trifluoroacetic acid/trifluoroacetic anhydride followed by in situ hydrolysis of the ester or via direct C?H hydroxylation. A brief analysis of substrate scope and limitation, reaction mechanism as well as synthetic utility of these reactions has been included. 相似文献
25.
Krishna Radhakrishnan Satyajit Gupta Divya Prakash Gnanadhas Praveen C. Ramamurthy Dipshika Chakravortty Ashok M. Raichur 《Particle & Particle Systems Characterization》2014,31(4):449-458
The fabrication of a mesoporous silica nanoparticle (MSN)?protamine hybrid system (MSN?PRM) is reported that selectively releases drugs in the presence of specific enzyme triggers present in the proximity of cancer cells. The enzyme trigger involved is a protease called trypsin, which is overexpressed in certain specific pathological conditions, such as inflammation and cancer. Overexpression of trypsin is known to be associated with invasion, metastasis, and growth in several cancers, such as leukemia, colon cancer, and colorectal cancer. The current system (MSN–PRM) consists of an MSN support in which mesopores are capped with an FDA‐approved peptide drug protamine, which effectively blocks the outward diffusion of the drug molecules from the mesopores of the MSNs. On exposure to the enzyme trigger, the protamine cap disintegrates, opening up the molecular gates and releasing the entrapped drug molecules. The system exhibits minimal premature release in the absence of the trigger and selectively releases the encapsulated drugs in the presence of the proteases secreted by colorectal cancer cells. The ability of the MSN–PRM particles to deliver anticancer drugs to colorectal cancer cells has also been demonstrated. The hydrophobic drug is released into cancer cells subsequent to disintegration of the protamine cap, resulting in cell death. Drug‐induced cell death in colorectal cancer cells is significantly enhanced when the hydrophobic drug that is known to degrade in aqueous environments is encapsulated in the MSN–PRM system in comparison to the free drug (P < 0.05). The system, which shows good biocompatibility and selective drug release, is a promising platform for cancer specific drug delivery. 相似文献
26.
Bulking up with F: The title reaction proceeds using 1?mol?% of the new perfluoroisopropyl chiral disulfonimide catalyst 1 to deliver several 2,6-disubstituted and 2,5,6-trisubstituted dihydropyrones in good yields and with excellent enantiomeric ratios. The utility of this methodology is illustrated with the first enantioselective synthesis of a potent aromatase inhibitor. 相似文献
27.
Hill JP Subbaiyan NK D'Souza F Xie Y Sahu S Sanchez-Ballester NM Richards GJ Mori T Ariga K 《Chemical communications (Cambridge, England)》2012,48(33):3951-3953
Tetrapyrazinoporphyrazine substituted at its periphery with eight antioxidant 3,5-di-t-butyl-4-hydroxyphenyl groups behaves as a turn-on fluorescent sensor for fluoride anions. Conversely, the precursor antioxidant-substituted 1,2-phthalonitrile was found to act in turn-off mode suggesting that the origin of the phenomenon lies at the phenolate-substituted 1,4-pyrazinyl moiety. 相似文献
28.
Mikaël Orain Frdric Grisch Eric Jourdanneau Bjorn Rossow Christian Guin Brigitte Trtout 《Comptes Rendus Mecanique》2009,337(6-7):373-384
Simultaneous measurements of PLIF-kerosene and PLIF-OH have been successfully performed in a multipoint injection system for various overall equivalence ratio, air inlet temperature between 480 and 730 K and pressure up to 2.2 MPa. Single shot 2D-maps of the spatial distribution of kerosene vapour and OH radical in the combustor have been recorded with good signal-to-noise ratio. Results show that depending on the split between the pilot and the main injectors, the flame front exhibits a single or a double structure. Good spatial correlation between the repartition of the kerosene vapour and the position of the flame front was observed; in particular, no “dark zone” is observed between the fuel and the flame front. As temperature and pressure increase, fuel evaporation improves and the spatial distribution of OH radical becomes more homogeneous in the combustor, suggesting a partially-distributed combustion. To cite this article: M. Orain et al., C. R. Mecanique 337 (2009). 相似文献
29.
Nonlinear finite element analysis of functionally graded plates integrated with patches of piezoelectric fiber reinforced composite 总被引:1,自引:0,他引:1
In this paper, a nonlinear static finite element analysis of simply supported smart functionally graded (FG) plates in the presence/absence of the thermal environment has been presented. The substrate FG plate is integrated with the patches of piezoelectric fiber reinforced composite (PFRC) material which act as the distributed actuators of the plate. The material properties of the FG substrate plate are assumed to be temperature dependent and graded along the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The derivation of this nonlinear thermo-electro-mechanical coupled finite element model is based on the first order shear deformation theory and the Von Karman type geometric nonlinearity. The numerical solutions of the nonlinear equations of the finite element model are obtained by employing the direct iteration method. The numerical illustrations suggest the potential use of the distributed actuator made of the PFRC material for active control of nonlinear deformations of smart FG structures. The effects of volume fraction index of the FG material of the substrate plates and the locations of the PFRC patches on the control authority of the patches are investigated. Emphasis has also been placed on investigating the effect of variation of piezoelectric fiber orientation angle in the PFRC patches on their actuation capability for counteracting the large deflections of FG plates. 相似文献
30.
TheK-electron capture probabilities (P k) for the 58 keV state and the ground state of159Tb in the decay of159Dy have been determined. The measured values,P k 58 =0.81±0.05 andP k 0 =0.79±0.06 are found to be in excellent agreement with theoretical results. 相似文献