[6]-Gingerol-loaded cellulose acetate electrospun fibers as a topical carrier for controlled release

[6]-Gingerol (6 % w/v)-loaded cellulose acetate (12 % w/v CA; MW ~ 3 × 10⁴ g/mol) fibers (375 ± 107 nm) were prepared by electrospinning at 7.5 kV. ATR-FTIR spectra indicated that the mixture was miscible at this composition. Differential scanning calorimetry revealed that [6]-gingerol was uniformly dispersed in the CA matrix and interrupted the hydrogen bond formation among the CA chains. Controlled release study showed that ~97 % of the loaded [6]-gingerol could be released from the loaded fibers to the acetate buffer solution at 37 °C, whereas only ~74 % of it could be done from the corresponding films. About 92 % of [6]-gingerol in the fibers was dramatically released within 4 h. Release was mainly governed by a diffusion-controlled mechanism. The radical scavenging assay showed antioxidant activity of the loaded fibers. The in vitro cytotoxicity test revealed that the viability of L-929 mouse fibroblast cells to the loaded fibers was ~65 %.     

Effects of Reaction Parameters in Catalysis of Glycerol Oxidation by Citrate-Stabilized Gold Nanoparticles

Abstract  

This work describes a catalytic oxidation of glycerol using citrate-stabilized gold nanoparticles (citrate-AuNPs) having a mean diameter of 22 ± 3 nm. A careful product analysis was performed by mean of high-performance liquid chromatography, liquid chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy. Effects of reaction temperature, oxygen pressure, catalyst and reactant concentration, and NaOH/glycerol molar ratio on glycerol conversion, and product yields were investigated. The glycerol conversion and glyceric acid yield were optimum when the oxidation was performed using 0.6 M glycerol and NaOH at 80 °C under 3 bar of O₂ pressure in the presence of 50 ppm citrate-AuNPs catalyst for 3 h.     

A biobjective model for production planning in a cement factory

This paper is an illustration of the application of biobjective linear programming to determining the optimal allocation of production materials to the major production facilities. The system under consideration is a cement factory. However, the approach and methodology are sufficiently general that the method can be applied to similar problems in other firms.Two objectives of the factory are distinguished: minimization of manufacturing cost and maximization of capacity utilization. Addressed to the needs of the biobjective case, a technique, which is referred to as ‘compromise constraint’ technique, is introduced.     

A mathematical model for industrial projects location

The location of an industrial project is one of the major decisions an entrepreneur has to take. The classical approach in locational analysis is based on cost minimization (especially the aggregate transport cost). Later investigations have dealt with profit maximization. This paper presents the method of developing a comprehensive model for determining the optimum plant location for an industry—considering both the objective (quantitative) factors and the subjective (non-quantitative) factors. The approach followed here identifies all the objective factors and the subjective factors at the micro level and optimizes the overall benefit to the entrepreneur. A method has been devised to evaluate the intangible factors and to combine them with the tangible factors to obtain the overall locational measure. This is done by converting the factors into consistent and dimensionless indices for comprehensive evaluation. Thus the model presented here can be used as a tool to determine the optimum plant location for a new industrial project and also to establish priorities among the feasible plant locations.     

Design of attribute control charts for multistage production systems-based on cost criteria

This paper develops a method to design attribute control charts, p-charts and c-charts, for multistage production systems based on quality cost criteria. The production systems are structured and formulated as a dynamic programming model. Each productions station and its inspection station is viewed as a combined station and is treated as the stage in the dynamic programming model. The model has quality distribution as the state variable and the stage transformation of this model is also developed. the stage return of this dynamic programming model is the quality cost of implementing an attribute control chart to that stage and the decision variables are the control chart parameters, n-sample size and control limits. Methods to combine quality distributions for finding type I and type II errors are then developed. As the dynamic programming model has quality distribution as state variable, conventional methods of solving dynamic programming problems are not applicable. A method, for solving this model, is thus developed based on branch and bound approach. The method itself may be applied to other dynamic programming problems where conventional methods are inefficient or not applicable. An example of the foundry process of cylinder liners is included to illustrate the developed method.     

A High Speed Autofocusing System for Micro System Applications

In this paper, we present a high speed autofocus system for micro system applications and design a look-up-table based autofocusing algorithm for applications when a target object is always visible, e.g., manufacturing parts with alignment fiducials. We perform an evaluation of 24 focus measures to verify that which focus measure is the best for the look-up-table based method. From the evaluation, we find that the Chebyshev moments-based focus measure (CHEB) is the most suitable. Furthermore, we also develop a look-up-table based autofocus system that uses CHEB as the focus measure. In training phase, we offline construct a table from training images of an object that are captured at several lens distances. Each entry of table consists of focus measure computed from image and lens distance. In working phase, given an input image, the algorithm first computes the focus measure and then finds the best match focus measure from the table and looks up the corresponding lens position for moving it into the in-focus position. Our algorithm can perform autofocusing within only 2 steps of lens moving. The experiment shows that the system can perform high speed autofocusing of micro objects.     

Stark spectroscopy of mixed-valence systems

Many mixed-valence systems involve two or more states with different electric dipole moments whose magnitudes depend upon the charge transfer distance and the degree of delocalization; these systems can be interconverted by excitation of an intervalence charge transfer transition. Stark spectroscopy involves the interaction between the change in dipole moment of a transition and an electric field, so the Stark spectra of mixed-valence systems are expected to provide quantitative information on the degree of delocalization. In limiting cases, a classical Stark analysis can be used, but in intermediate cases the analysis is much more complex because the field affects not only the band position but also the intrinsic bandshape. Such non-classical Stark effects lead to widely different bandshapes. Several examples of both classes are discussed. Because electric fields are applied to immobilized samples, complications arise from inhomogeneous broadening, along with other effects that limit our ability to extract unique parameters in some cases. In the case of the radical cation of the special pair in photosynthetic reaction centres, where the mixed-valence system is in a very complex but structurally well-defined environment, a detailed analysis can be performed.     

Processability enhancement of poly(lactic acid-co-ethylene terephthalate) by blending with poly(ethylene-co-vinyl acetate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and poly(butylene succinate)

Processability enhancement feasibility of an in-house synthesized poly(lactic acid-co-ethylene terephthalate), PLET, is investigated by blending with commercial poly(ethylene-co-vinyl acetate), EVA, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, and poly(butylene succinate), PBS. The three blend systems are prepared by varying PLET contents, and their properties are characterized. DSC, SEM, and FTIR results indicate that PLET/EVA blends are immiscible, while the corresponding PLET/PBS and PLET/PHBV blends are miscible and partially miscible, respectively. DMA results show that the three blend systems have storage modulus comparable to those of commercial EVA, PHBV, and PBS, when PLET content is kept lower than 50, 25, and 25 wt%, respectively. PLET/EVA blends show higher thermal stability, compared to those of the other two blend systems. Results on degradability tests indicate that PLET/PBS blends show highest hydrolytic degradability, compared to the other two blends, as both blend constituents are associated in the hydrolytic degradation.     

Book Reviews

Proceedings of the Conference on Industrial Systems Engineering and Management in Developing Countries, 1980, Edited by M. T. Tabucanon and P. Adulbhan. The Asian Institute of Technology, Bangkok, Thailand, 1980

Queueing Tables and Graphs, F.S. Hillier and O.S. Yu with D. M. Avis, L. D. Fossett, F. D. Lo, and M. I. Reiman Elsevier North Holland, Inc., New York, 1981, 231+ pages.