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71.
72.
Montagnon T Noutsias D Alexopoulou I Tofi M Vassilikogiannakis G 《Organic & biomolecular chemistry》2011,9(7):2031-2039
In this article, we explore how changes in the positioning of pendant hydroxyl functionalities in the photooxygenation substrate dramatically alter the course of furan oxidations that are initiated by singlet oxygen; and, how these different reactivities can be harnessed through cascade reaction sequences to access, rapidly and effectively, a broad range of important natural product motifs. 相似文献
73.
Raffaello Papadakis Ioanna Deligkiozi Athanase Tsolomitis 《Analytical and bioanalytical chemistry》2010,397(6):2253-2259
This work deals with the design, synthesis, and characterization of a new solvatochromic dye. The intense solvatochromic behavior
of this new synthesized non symmetric viologen was investigated using UV–Vis spectrophotometry. A further purpose was the
study of the interactions between the solvent and solute molecules responsible for the solvatochromism. Several protic and
aprotic solvents were used, and the resulting absorption maxima wavenumbers obtained via UV–Vis spectrophotometry, were correlated
with the solvent polarity parameters, E
T
(30) (Dimroth–Reichardt solvent polarity parameter) and the Gutmann’s donor number (DN) using the biparametric model introduced
by Krygowski and Fawcett. The analysis of the relative contribution of each parameter has clearly shown that the dominating
interaction responsible for the solvatochromic behavior observed is the proton donation by the solute molecules to the solvent
molecules, the latter acting as a Lewis bases. This is an interaction which can be described by DN. Additionally, the good
correlation with the Kamlet–Taft parameter β is in good agreement. 相似文献
74.
75.
Zhang W Ntai I Bolla ML Malcolmson SJ Kahne D Kelleher NL Walsh CT 《Journal of the American Chemical Society》2011,133(14):5240-5243
Pacidamycins are a family of uridyl peptide antibiotics that inhibit the translocase MraY, an essential enzyme in bacterial cell wall biosynthesis that to date has not been clinically targeted. The pacidamycin structural skeleton contains a doubly inverted peptidyl chain with a β-peptide and a ureido linkage as well as a 3'-deoxyuridine nucleoside attached to DABA(3) of the peptidyl chain via an enamide linkage. Although the biosynthetic gene cluster for pacidamycins was identified recently, the assembly line of this group of peptidyl nucleoside antibiotics remained poorly understood because of the highly dissociated nature of the encoded nonribosomal peptide synthetase (NRPS) domains and modules. This work has identified a minimum set of enzymes needed for generation of the pacidamycin scaffold from amino acid and nucleoside monomers, highlighting a freestanding thiolation (T) domain (PacH) as a key carrier component in the peptidyl chain assembly as well as a freestanding condensation (C) domain (PacI) catalyzing the release of the assembled peptide by a nucleoside moiety. On the basis of the substrate promiscuity of this enzymatic assembly line, several pacidamycin analogues were produced using in vitro total biosynthesis. 相似文献
76.
Vasiliadou IA Papoulis D Chrysikopoulos CV Panagiotaras D Karakosta E Fardis M Papavassiliou G 《Colloids and surfaces. B, Biointerfaces》2011,84(2):354-359
The attachment of Pseudomonas (P.) putida onto well (KGa-1) and poorly (KGa-2) crystallized kaolinite was investigated in this study. Batch experiments were carried out to determine the attachment isotherms of P. putida onto both types of kaolinite particles. The attachment process of P. putida onto KGa-1 and KGa-2 was adequately described by a Langmuir isotherm. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance were employed to study the attachment mechanisms of P. putida. Experimental results indicated that KGa-2 presented higher affinity and attachment capacity than KGa-1. It was shown that electrostatic interactions and clay mineral structural disorders can influence the attachment capacity of clay mineral particles. 相似文献
77.
We use techniques due to Moti Gitik to construct models in which for an arbitrary ordinal ?, is both the least measurable and least regular uncountable cardinal. 相似文献
78.
In this work, a new [2]rotaxane consisted of a diazobenzene containing π-conjugated linear compartment, including the 4,4′-bipyridyl moiety and α-cyclodextrin (α-CD) as the macrocyclic compartment, was synthesised with yields of nearly 57% and fully characterised. α-CD easily assembled with the linear compartment and suitable bulky ends (stoppers) in water to give a new [2]rotaxane. The characterisation of this supramolecular compound was accomplished using several spectroscopic techniques such as 1H NMR, 13C NMR and 2D NMR spectroscopy, powder X-ray diffraction, fourier transform infrared spectroscopy, induced circular dichroism and UV–vis spectrophotometry, as well as scanning electron microscopy and Energy Dispersive X-ray. Furthermore, the reversible E–Z photoisomerisation of both [2]rotaxane and its molecular dumbbell was investigated by irradiation with UV light. 相似文献
79.
Ioanna?MakarouniEmail author John?Psarras Eleftherios?Siskos 《Annals of Operations Research》2015,225(1):45-63
In this paper we develop an interactive decision analysis approach to treat a large scale bicriterion integer programming problem, addressing a real world assembly line scheduling problem of a manufacturing company. This company receives periodically a set of orders for the production of specific items (jobs) through a number of specialised production (assembly) lines. The paper presents a non compensatory approach based on an interactive implementation of the ε-constraint method that enables the decision maker to achieve a satisfactory goal for each objective separately. In fact, the method generates and evaluates a large number of non dominated solutions that constitute a representative sample of the criteria ranges. The experience with a specific numerical example shows the efficiency and usefulness of the proposed model in solving large scale bicriterion industrial integer programming problems, highlighting at the same time the modelling limitations. 相似文献
80.
Dimitrios Tsesmetzis Ioanna Roussaki Efstathios Sykas 《European Journal of Operational Research》2008
Making the provision of services QoS-aware is to the advantage of both clients and providers in the e-business domain. This paper studies the problem of providers that receive multiple concurrent requests for services demonstrating different QoS properties. It introduces the “Selective Multiple Choice Knapsack Problem” that aims to identify the services, which should be delivered in order to maximise the provider’s profit, subject to maximum bandwidth constraints. This problem is solved by a proposed algorithm that has been empirically evaluated via numerous experiments. 相似文献