Synthesis and Antimycobacterial Evaluation on Arylsulfonyl and Arylcarbonyl Derivatives of Ofloxacin

Four ofloxacin derivatives 3, 5, 6 , and 11 were found to exhibit > 90% inhibition on the growth of M. tuberculosis at a concentration of 6.25 μg/mL. Compounds 3, 5 and 11 have also exhibited a broad spectrum of antibacterial activities while 8‐fluoro‐3‐methyl‐9‐[4‐(4‐nitrophenylsulfonyl)piperazin‐1‐yl)‐6‐oxo‐2,3‐dihydro‐6H‐1‐oxo‐3a‐azaphenalene‐5‐carboxylic acid ( 6 ), which exhibited potent activity against the growth of TB with the MIC of 2.23 μg/mL and a selectivity index (SI) of > 14.80, was inactive against the growth of G(+)‐ and G(‐)‐bacteria. Selective anti‐TB activity was achieved by the introduction of an arylsulfonyl group at C‐7 piperazin‐4‐yl of N‐demethyl ofloxacin. Compound 6 is species‐specific, exhibiting no significant activity against the growth of bacterial species other than M. tuberculosis, which implied the possibility of developing new specific anti‐TB drug candidates without inducing cross resistance with other currently used antibacterial drugs. Structural optimization of 6 is on‐going.     

Using a Fuzzy Piecewise Regression Analysis to Predict the Nonlinear Time-Series of Turbulent Flows with Automatic Change-Point Detection

Research has already shown that turbulent flow consists of some coherent time- and space-organized vortical structures. Some dynamic systems and experimental models are employed to understand the turbulent generation mechanism. However, these approaches still cannot provide a good nonlinear analysis of turbulent time-series. In the real turbulent flow, very complicated nonlinear behaviors, which are affected by many vague factors are present. Based on the nonlinear behavior and the results of from this traditional research, we introduce multivariate statistical analysis of an experimental study to explain practical phenomenon. In this paper, a new approach of fuzzy piecewise regression analysis with automatic change-point detection is proposed to predict the nonlinear time-series of turbulent flows. In order to show the practicality and usefulness of this model, we present an example of predicting the near-wall turbulence time-series as a verifiable model. The results of practical applications show that the proposed method is appropriate and appears to be useful in nonlinear analysis and in fuzzy environments to predict the turbulence time-series. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reversible Phase Transformation and Luminescence of Cadmium(II)–Dipyridylamide‐Based Coordination Frameworks

We have synthesized a series of 1D double‐zigzag ({[Cd(paps)₂(H₂O)₂](ClO₄)₂}_n ( 1 ), {[Cd(papo)₂(H₂O)₂](ClO₄)₂}_n ( 3 ), and {[Cd(papc)₂(H₂O)₂](ClO₄)₂}_n ( 5 )) and 2D polyrotaxane frameworks ([Cd(papc)₂(ClO₄)₂]_n ( 6 )) by the reaction of Cd(ClO₄)₂ with dipyridylamide ligands N,N′‐bis(pyridylcarbonyl)‐4,4′‐diaminodiphenyl thioether (paps), N,N′‐bis(pyridylcarbonyl)‐4,4′‐diaminodiphenyl ether (papo), and N,N′‐(methylenedi‐p‐phenylene)bispyridine‐4‐carboxamide (papc), respectively, where their molecular structures have been determined by X‐ray diffraction studies. Based on the powder X‐ray data (PXRD) of compound 3 and its Zn^II analogue, heating the double‐zigzag framework of compound 3 can give the polyrotaxane framework of [Cd(papo)₂(ClO₄)₂]_n ( 4 ) and grinding this powder sample in the presence of moisture resulted in its complete conversion back into the pure double‐zigzag framework. In addition, heating the double‐zigzag frameworks of compounds 1 and 5 can induce structural transformation into their respective polyrotaxanes, whereas grinding these solid samples in the presence of moisture did not lead to the formation of the double zigzags. Herein, we investigated the effect of the metal (from Zn^II to Cd^II) on the assembly process and luminescence properties, as well as on the particularly intriguing structural transformation of a series of papx‐based frameworks. In fact, the assembly behavior and luminescence properties of the Cd^II? papx and Zn^II? papx frameworks were really similar. However, both Zn^II? papx (x=s, o) frameworks can perform reversible structural transformation, but only the Cd^II? papo framework can do it. Therefore, a delicate metal effect on such a new structural transformation can be observed.     

Highly Sensitive Quantitative Analysis of 1-[3-(Furo[3,2-c]quinolin-4-ylamino)phenyl]ethanone Oxime, a New Antitumor Agent, in Rat Plasma by LC with Electrochemical Detection

1-[3-(Furo[3,2-c]quinolin-4-ylamino)phenyl]ethanone oxime (CCK2) is an antitumor agent which was especially active against the growth of the renal cancer cell UO-31 (GI₅₀ = 0.03 μm) and the two melanoma cancer cells UACC-257 (GI₅₀ < 0.01 μm) and UACC-62 (GI₅₀ < 0.01 μm) in cytotoxicity evaluation of NCI’s full panel of 60 human cancer cell lines. From structure–activity relationships for amsacrine and CCK2, CCK2 is, moreover, expected to have a longer half-life than amsacrine in plasma. A sensitive high-performance liquid chromatographic method with electrochemical detection has therefore been developed and validated for determination of the pharmacokinetics of CCK2 in rats. Plasma samples were spiked with 2-naphthol as internal standard and extracted with dichloromethane. The analytes were separated on a C₁₈ reversed-phase column (55 × 4 mm) with 20% acetonitrile, 5% tetrahydrofuran, and 75% pH 3.0 McIlvaine buffer as mobile phase at a flow rate of 1.0 mL min^?1. Electrochemical detection of CCK2 was performed at 1.0 V and 20 nA. Intra-day and inter-day precision and accuracy were acceptable down to the limit of quantification of 10 ng mL^?1. The lower limit of detection was 5 ng mL^?1. In an in vivo study pharmacokinetic data were determined for CCK2 in rat after intravenous administration of 6, 12, and 24 μmol kg^?1. The apparent volume of distribution, elimination half-life, and clearance were not significantly different among the three doses. The area under the plasma concentration–time curve increased in proportion to increasing dose. The elimination half-life of CCK2 was 3.4 times that of amsacrine. CCK2 might, therefore, have the potential to be tested clinically. The results also showed that this selective, sensitive, and reproducible LC method could be successfully applied to investigation of the pharmacokinetics of CCK2.     

Triterpenoids from the Stems of Momordica charantia

Two new cucurbitane triterpenes, (23E)‐7β‐methoxycucurbita‐5,23,25‐trien‐3β‐ol ( 1 ) and 23,25‐dihydroxy‐5β,19‐epoxycucurbit‐6‐ene‐3,24‐dione ( 2 ), and a new D : C‐friedooleanane triterpene, 3α‐[(E)‐feruloyloxy]‐D : C‐friedooleana‐7,9(11)‐dien‐29‐oic acid ( 3 ), together with two known D : C‐friedooleanane triterpenes, 3β‐[(E)‐feruloyloxy]‐D : C‐friedooleana‐7,9(11)‐dien‐29‐oic acid ( 4 ) and 3‐oxo‐D : C‐friedooleana‐7,9(11)‐dien‐29‐oic acid ( 5 ), were isolated from the stems of Momordica charantia. The structures of the new compounds 1 – 3 were determined by spectroscopic methods.     

Using oppositely charged ions to operate a three-station [2]rotaxane in two different switching modes

A [2]rotaxane undergoes switching of its bis-p-xylyl-[26]crown-6 (BPX26C6) component away from its guanidinium station toward its 2,2'-bipyridyl and carbamate stations upon the addition and removal of Zn(2+) and PO(4)(3-) ions, respectively.     

Combined DEMATEL technique with hybrid MCDM methods for creating the aspired intelligent global manufacturing & logistics systems

The concept of globalization has been prosperous in the past decades while manufacturing as well as logistics have already become one of the most significant issues in the globalization era. However, while modern globalized firms are leveraging both global manufacturing resources as well as logistics systems for pursuing higher quality, lower cost as well as product differentiation, how to evaluate, selecting an appropriate global manufacturing strategy by considering issues from both aspects of global manufacturing as well as logistics has become one of the most critical and difficult issues. Moreover, how the chosen intertwined global manufacturing as well as logistics system is to be optimized so that the aspired level of the global manufacturing system can be achieved have few been addressed. Thus, this research aims to resolve the above mentioned global manufacturing and logistics strategy selection as well as system reconfiguration issue. A Decision Making Trial and Evaluation Laboratory (DEMATEL) technique based novel multiple criteria decision making (MCDM) method with Analytic Network Process (ANP), Grey Relational Analysis (GRA) as well as VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) will be proposed for selecting and re-configuring the aspired global manufacturing and logistics system. An empirical study based on the global manufacturing and logistics system design of a semiconductor company will be provided for verifying the effectiveness of this proposed methodology.     

Investigations on the Photoreactions of Phenothiazine and Phenoxazine in Presence of 9-cyanoanthracene by Using Steady State and Time Resolved Spectroscopic Techniques

By using electrochemical, steady state and time resolved (fluorescence lifetime and transient absorption) spectroscopic techniques, detailed investigations were made to reveal the mechanisms of charge separation or forward electron transfer reactions within the electron donor phenothiazine (PTZH) or phenoxazine (PXZH) and well known electron acceptor 9-cyanoanthracene (CNA). The transient absorption spectra suggest that the charge separated species formed in the excited singlet state resulted from intermolecular photoinduced electron transfer reactions within the donor PTZH (or PXZH) and CNA acceptor relaxes to the corresponding triplet state. Though alternative mechanisms of via formations of contact neutral radical by H-transfer reaction have been proposed but the observed results obtained from the time resolved measurements indicate that the regeneration of ground state reactants is primarily responsible due to direct recombination of triplet contact ion-pair (CIP) or solvent-separated ion-pair (SSIP).     

HDTV/Gigabit Ethernet over bidirectional WDM-PON based on injection-locked Fabry-Perot laser diodes

Bidirectional high definition television (HDTV)/Gigabit Ethernet over wavelength-division-multiplexing (WDM)-passive optical network (PON) based on injection-locked Fabry-Perot laser diodes (FP LDs) as transmitters were proposed and demonstrated. Injection-locked FP LDs, a particularly inexpensive option, are used to replace conventional distributed feedback (DFB) LDs. Services with 77 HDTV channels and 1 Gigabit Ethernet channel connection were successfully demonstrated over 40 km single-mode fiber (SMF) transport. Good performance of bit error rate (BER) and clear eye diagram were achieved in our proposed bidirectional WDM-PON.