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111.
Ki Mun Jung Lyn C Thomas Mee Chi So 《The Journal of the Operational Research Society》2015,66(10):1656-1668
Data-based scorecards, such as those used in credit scoring, age with time and need to be rebuilt or readjusted. Unlike the huge literature on modelling the replacement and maintenance of equipment there have been hardly any models that deal with this problem for scorecards. This paper identifies an effective way of describing the predictive ability of the scorecard and from this describes a simple model for how its predictive ability will develop. Using a dynamic programming approach one is then able to find when it is optimal to rebuild and when to readjust a scorecard. Failing to readjust or rebuild a scorecard when they aged was one of the defects in credit scoring identified in the investigations into the sub-prime mortgage crisis. 相似文献
112.
Rin Jang Ki Hun Kim Shabi Abbas Zaidi Won Jo Cheong Myeong Hee Moon 《Electrophoresis》2011,32(16):2167-2173
In this study, an open‐tubular capillary electrochromatography (OT‐CEC) column with a monolithic layer of molecularly imprinted polymer (MIP) based on methacrylic acid, ethylene glycol dimethacrylate, and 4‐styrenesulfonic acid was utilized for the simultaneous separation and characterization of phospholipid (PL) molecular structures by interfacing with electrospray ionization‐tandem mass spectrometry (ESI‐MS‐MS). Introducing an MIP‐based monolith along with charged species at the OT column made it possible to separate PL molecules based on differences in head groups and acyl chain lengths in CEC. For the interface of OT‐CEC with ESI‐MS‐MS, a simple nanospray interface utilizing a sheath flow was developed and the resulting OT‐CEC‐ESI‐MS‐MS was able to separate PL standards (phosphatidylserines, phosphatidylethanolamines, phosphatidylglycerols, phosphatidic acid, and lysophosphatidylglycerols). The developed method was applied to human urinary lipid extracts, and resulted in the separation and structural identification of 18 molecules by data‐dependent collision‐induced dissociation. 相似文献
113.
M. V. Pergal J. V. Džunuzović M. Kićanović V. Vodnik M. M. Pergal S. Jovanović 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(13):2251-2256
Novel polyurethanes (PUs) were synthesized using hydroxy-terminated hyperbranched polyester (BH-20) and 4,4′-methylenediphenyl
diisocyanate (MDI) as hard segments and hydroxy-terminated ethylene oxide-poly(dimethylsiloxane)-ethylene oxide triblock copolymer
(PDMS-EO) as soft segment, with soft segment content ranging from 30 to 60 wt %. The PUs were synthesized by two-step solution
polymerization method. The influence of the soft segment content on the structure, swelling behavior and thermal properties
of PUs was investigated. According to the results obtained by swelling measurements, the increase of the hard segment content
resulted in the increase of the crosslinking density of synthesized samples. DSC results showed that the glass transition
temperatures increase from 36 to 65°C with increasing hard segment content. It was demonstrated using thermogravimetric analysis
(TGA) that thermal stability of investigated PUs increases with increase of the soft PDMS-EO content. This was concluded from
the temperatures corresponding to the 10 wt % loss, which represents the beginning of thermal degradation of samples. 相似文献
114.
B. Lakshmi Prakash Gouda Avaji K.N. Shivananda Praveen Nagella S.H. Manohar K.N. Mahendra 《Polyhedron》2011,30(9):1357-1515
A series of binuclear Co(II), Ni(II) and Cu(II) complexes were synthesized by the template condensation of glyoxal, biacetyl or benzil bis-hydrazide, 2,6-diformyl-4-methylphenol and Co(II), Ni(II) or Cu(II) chloride in a 2:2:2 M ratio in ethanol. These 22-membered macrocyclic complexes were characterized by elemental analyses, magnetic, molar conductance, spectral, thermal and fluorescence studies. Elemental analyses suggest the complexes have a 2:1 stoichiometry of the type [M2LX2]·nH2O and [Ni2LX22H2O]·nH2O (where M = Co(II) and Cu(II); L = H2L1, H2L2 and H2L3; X = Cl; n = 2). From the spectroscopic and magnetic studies, it has been concluded that the Co(II) and Cu(II) complexes display a five coordinated square pyramidal geometry and the Ni(II) complexes have a six coordinated octahedral geometry. The Schiff bases and their metal complexes have also been screened for their antibacterial and antifungal activities by the MIC method. 相似文献
115.
Park KD Kim D Reamtong O Eyers C Gaskell SJ Liu R Kohn H 《Journal of the American Chemical Society》2011,133(29):11320-11330
We have advanced a useful strategy to elucidate binding partners of ligands (drugs) with modest binding affinity. Key to this strategy is attaching to the ligand an affinity bait (AB) and a chemical reporter (CR) group, where the AB irreversibly attaches the ligand to the receptor upon binding and the CR group is employed for receptor detection and isolation. We have tested this AB&CR strategy using lacosamide ((R)-1), a low-molecular-weight antiepileptic drug. We demonstrate that using a (R)-lacosamide AB&CR agent ((R)-2) 14-3-3 ζ in rodent brain soluble lysates is preferentially adducted, adduction is stereospecific with respect to the AB&CR agent, and adduction depends upon the presence of endogenous levels of the small molecule metabolite xanthine. Substitution of lacosamide AB agent ((R)-5) for (R)-2 led to the identification of the 14-3-3 ζ adduction site (K120) by mass spectrometry. Competition experiments using increasing amounts of (R)-1 in the presence of (R)-2 demonstrated that (R)-1 binds at or near the (R)-2 modification site on 14-3-3 ζ. Structure-activity studies of xanthine derivatives provided information concerning the likely binding interaction between this metabolite and recombinant 14-3-3 ζ. Documentation of the 14-3-3 ζ-xanthine interaction was obtained with isothermal calorimetry using xanthine and the xanthine analogue 1,7-dimethylxanthine. 相似文献
116.
Synthesis of the proposed structure of lytophilippine A was accomplished employing SmI(2)-mediated 5-exo cyclization of an aldehydo β-alkoxyvinyl sulfoxide and ring-closing metathesis reaction. 相似文献
117.
Moustafa A. Gouda 《Journal of heterocyclic chemistry》2011,48(1):1-10
This review describe the synthesis and reactions of 3‐amino‐4,6‐dimethyl‐1H‐pyrazolo[3,4‐b]pyridine as building block for the synthesis of polyfunctionalized heterocyclic compounds with pharmacological interest. J. Heterocyclic Chem., 2011. 相似文献
118.
Antioxidant and antityrosinase activities of various extracts from the fruiting bodies of Lentinus lepideus 总被引:1,自引:0,他引:1
Yoon KN Alam N Lee KR Shin PG Cheong JC Yoo YB Lee TS 《Molecules (Basel, Switzerland)》2011,16(3):2334-2347
Lentinus lepideus is an edible mushroom currently available in Korea. The acetone, methanol and hot water extracts were prepared and assayed for their antioxidant and antityrosinase inhibitory activities. The hot water extract showed the strongest β-carotene-linoleic acid inhibition compared to the other extracts. At 8 mg/mL, the methanolic extract showed a high reducing power of 1.21. The acetone and methanol extracts were more effective in scavenging DPPH radicals than the hot water extract. The strongest chelating effect was obtained from the methanolic extract. Xanthine oxidase and tyrosinase inhibitory activities of the acetonic, methanol and hot water extracts increased with increasing concentration. Gallic acid, chlorogenic acid, vanillin, naringin, naringenin, formononetin, and biochanin-A were detected in the acetonitrile and hydrochloric acid (5:1) solvent extract. This study suggests that fruiting bodies of L. lepideus can potentially be used as a readily accessible source of natural antioxidants. 相似文献
119.
Kim KC Kulkarni AD Johnson JK Sholl DS 《Physical chemistry chemical physics : PCCP》2011,13(48):21520-21529
First principles calculations have played a useful role in screening mixtures of complex metal hydrides to find systems suitable for H(2) storage applications. Standard methods for this task efficiently identify the lowest energy reaction mechanisms among all possible reactions involving collections of materials for which DFT calculations have been performed. The resulting mechanism can potentially differ from physical reality due to inaccuracies in the DFT functionals used, or due to other approximations made in estimating reaction free energies. We introduce an efficient method to probe the robustness of DFT-based predictions that relies on identifying reactions that are metastable relative to the lowest energy reaction path predicted with DFT. An important conclusion of our calculations is that in many examples DFT cannot unambiguously predict a single reaction mechanism for a well defined metal hydride mixture because two or more mechanisms have reaction energies that differ by a small amount. Our approach is illustrated by analyzing a series of single step reactions identified in our recent work that examined reactions with a large database of solids [Kim et al., Phys. Chem. Chem. Phys. 2011, 13, 7218]. 相似文献
120.
This article presents a simple, low-cost method of fabrication and the applications of flexible polystyrene microfluidic devices with three-dimensional (3D) interconnected microporous walls based on treatment using a solvent/non-solvent mixture at room temperature. The complete fabrication process from device design concept to working device can be completed in less than an hour in a regular laboratory setting, without the need for expensive equipment. Microfluidic devices were used to demonstrate gas generation and absorption reactions by acidifying water with carbon dioxide (CO(2)) gas. By selectively treating the microporous structures with oxygen plasma, acidification of water by acetic acid (distilled white vinegar) perfusion was also demonstrated with the same device design. 相似文献