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High-performance liquid chromatography for analytical and small-scale preparative separation of (R,S)-mexiletine using (S)-(—)-(N)-trifluoroacetyl-prolyl chloride and (1S)-(—)-camphanic chloride and recovery of native enantiomer by detagging

Dixit S., Dubey R., Bhushan R.

Acta Chromatographica

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2014

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Vol. 26, no. 4

625--636

EN

A reversed phase high-performance liquid chromatographic method has been established for enantioseparation of (R, S)-mexiletine. Two volatile and thermally stable acyl chlorides, viz., (S)-(—)-(N)-trifluoro acetyl prolyl chloride and (1S)-(—)-camphanic chloride, were used as chiral derivatizing reagents. Binary composition of aqueous trifluoroacetic acid (0.1%)-acetonitrile as mobile phase was successful with ultraviolet (UV) detection at 210 nm. The method was optimized and validated for accuracy, precision, and limit of detection. The limit of detection was found to be 45 ng mL -1 and 80 ng mL -1 for the two types of diastereomers. Besides, kinetic resolution was achieved, and the experimental conditions optimized for this purpose provided diastereomeric excess up to 74% for (R)-isomer. On achieving a resolution value greater than 2, the optimized method for analytical enantioseparation was scaled-up to smallscale preparative level, and the native (R)-mexiletine was recovered by acid hydrolysis of the diastereomer.

2

Role of innovative supply chain practices and total quality management (TQM) on performance of Indian cement manufacturing firms : an empirical study

Dubey R., Chakrabarty A.

Polish Journal of Management Studies

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2011

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Vol. 4

96-119

EN

In extremely turbulent situation when world faces major economic crisis then particularly Indian manufacturing sector had major set back. In such situation some of Indian cement sector has demonstrated healthy performance through innovative supply chain practices. In this study author conducted an empirical study to understand how innovative practices in supply chain in combination with TQM (Total Quality Management) can help firm to reduce cost and improve customer satisfaction which in turn reflect high profitability and better market share. Out of five proposed model four model is accepted and fifth model is not supported by regression analysis. The findings clearly reveal that Indian cement Industry is quite in nascent stage to adopt Innovative supply chain practices.

PL

W wyjątkowo niespokojnych czasach, kiedy świat stawia czoła poważnemu kryzysowi gospodarczemu, szczególnie indyjski sektor wytwórczy doświadczył poważnego zahamowania. Pomimo takiej sytuacji, część indyjskiego sekora cementu wykazała dobrą wydajność dzięki zastosowaniu innowacyjnych praktyk w łańcuchu dostaw. W nieniejszej pracy autor przeprowadza badanie w celu zrozumienia jak innowacyjne praktyki w łańcuchu dostaw w połączeniu z zarządzaniem przez jakość (TQM) może pomóc przedsiębiorstwu zredukować koszty i poprawić satysfakcję klienta, co z kolei znajduje odzwierciedlenie w wysokiej rentowności i większym udziale w rynku. Z pięciu zaproponowanych modeli cztery zostały zaakceptowane, a piąty model nie jest wspierany przez analizę regresji. Wyniki jasno wykazują, że przemysł indyjskiego cementu znajduje się w stanie sprzyjającym zastosowaniu innowacyjnych praktyk w łańcuchu dostaw.

3

Control of a redundant 7DOF upper-limb power-assist exoskeleton robot

Hayashi Y., Kiguchi K., Dubey R.

Journal of Artificial Intelligence and Soft Computing Research

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2011

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Vol. 1, No. 3

207--214

EN

Many kinds of power-assist robots have been developed in order to assist daily activities or rehabilitation of the elderly or physically weak persons. Upper-limb power-assist robots are important to assist in many daily life activities such as eating, drinking, etc.. A human upper-limb has 7 degrees of freedom to achieve various tasks dexterously. Therefore, to assist all upper-limb joint motions of a human, the upper-limb power-assist robot is required to have 7DOF. To achieve a desired task, a person moves the hand to the desired position and orientation and/or applies certain amount of force to the target. Therefore, it is important that the upper-limb power-assist robots help control the hand position/ orientation or hand force of the user. However, the hand position/orientation or hand force is 6-dimensional vector, so the 7DOF upper-limb power-assist robot has a redundancy and in general, a pseudo-inverse matrix is used in the control. In this paper, an optimal control method is proposed to deal with the redundancy of the upper-limb power-assist exoskeleton robot considering comfortable motion of the user. The motion intention and the comfort of the user are taken into account in the pro-posed method. The effectiveness of the proposed method was evaluated by the experiments.