A genetic algorithm for the two-stage supply chain distribution problem associated with a fixed charge

This paper considers a two-stage distribution problem of a supply chain that is associated with a fixed charge. Two kinds of cost are involved in this problem: a continuous cost that linearly increases with the amount transported between a source and a destination, and secondly, a fixed charge, that incurs whenever there exists a transportation of a non-zero quantity between a source and a destination. The objective criterion is the minimisation of the total cost of distribution. A genetic algorithm (GA) that belongs to evolutionary search heuristics is proposed and illustrated. The proposed methodology is evaluated for its solution quality by comparing it with the approximate and lower bound solutions. Thus, the comparison reveals that the GA generates better solution than the approximation method and is capable of providing solution either equal or closer to the lower bound solution of the problem.     

Fiber-optic sensors for the estimation of oxygen gradients within biofilms on metals

This paper presents an optical approach to measure the oxygen gradients in biofilms grown on stainless-steel 316L. The sensor is constructed by immobilizing an oxygen-quenchable fluorophore at the tip of an optical fiber. The response time and reversibility of fiber-optic sensor have been analyzed. By mounting the optical fiber using a computerized micromanipulator, the vertical profiles of oxygen are measured with 10 μm depth resolution across biofilms on metal coupons. Steep concentration gradients of oxygen have been observed within the biofilm, both perpendicular and parallel to the metal surface. Optical response of the biofilm grown metal surface is found to be a consistent measure of the oxygen profiles within biofilms.     

Ultrasound assisted,VOSO4 catalyzed synthesis of 4-thiazolidinones: Antimicrobial evaluation of indazole-4-thiazolidinone derivatives

A simple and expedient multicomponent protocol was developed to synthesize 4-thiazolidinones by employing VOSO₄ as a catalyst under ultrasonic irradiation. The significant features of this protocol includes shorter reaction time, high yields, low catalyst loading, and also the catalyst can be recovered and reused up to next four cycles without significant loss in catalytic activity. All the synthesized novel indazole compounds were evaluated for their antibacterial and anti-biofilm activities. Compounds 9n, 9o and 9q showed promising activity (MIC value of 3.9?µg/mL) against K. planticola (MTCC 530). They also exhibited significant bactericidal activity against K. planticola (MTCC 530) (MBC value of 15.6?µg/mL). Additionally, 9n, 9o and 9q inhibited biofilm formation (IC₅₀ values ranging between 20.28–20.79?μg/mL) in this organism.     

A simple and rapid method for determination of boron in fast breeder reactor components

The present paper describes a new analytical method developed for direct determination of boron in steels using radio frequency glow discharge optical emission spectrometer. “Single parameter alternative method” technique has been used to optimize the various experimental conditions of glow discharge plasma such as forward power, gas pressure inside plasma chamber, pre-integration time, and integration time. Different emission lines for boron were studied and inter element interference effect is also discussed in the paper. A complete statistical analysis has been done to validate the developed method. A RSD of less than ±5% is achieved for boron in the range of 0.0010–0.020% in Steels using this method.     

Liquid crystal-gold nanoparticle composite-modified indium tin oxide (ITO) substrates and their electrochemical characterisation

A simple efficient strategy for the simultaneous synthesis and anchoring of liquid crystal (LC)-stabilised gold nanoparticles (NPs) on indium tin oxide (ITO) substrate is described. A monolayer of 3-mercaptopropyltrimethoxy silane (MPS) compound was formed on ITO and quality of the monolayer was assessed using electrochemical techniques namely cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Gold NP preparation was carried out on this monolayer-modified substrate (and on bare ITO), in a single-step reaction, simply by drop-casting a solution containing an appropriate amount of chloroauric acid and a LC compound possessing a terminal amino group, on the MPS monolayer-modified substrate and heating (70degree) for 2-3 min.. The LC compound served as a reducing agent as well as a capping ligand. LC-capped NPs were chemically anchored onto the ITO substrate through bonding to thiol moiety of the MPS. The CV and EIS analysis of the MPS monolayer showed a complete blocking behaviour for the electron transfer across the electrode/electrolyte interface confirming the formation of a high-quality dense compact monolayer. On the other hand, upon immobilisation of LC-gold NP composite on self-assembled monolayer-modified ITO substrates, both CV and impedance studies showed a small current indicating the gold NP-mediated electron transfer, thus confirming the successful immobilisation of NPs.     

Vibrational spectroscopy differentiates between multipotent and pluripotent stem cells

Over the last few years, there has been an increased interest in the study of stem cells in biomedicine for therapeutic use and as a source for healing diseased or injured organs/tissues. More recently, vibrational spectroscopy has been applied to study stem cell differentiation. In this study, we have used both synchrotron based FTIR and Raman microspectroscopies to assess possible differences between human pluripotent (embryonic) and multipotent (adult mesenchymal) stem cells, and how O(2) concentration in cell culture could affect the spectral signatures of these cells. Our work shows that infrared spectroscopy of embryonic (pluripotent) and adult mesenchymal (multipotent) stem cells have different spectral signatures based on the amount of lipids in their cytoplasm (confirmed with cytological staining). Furthermore, O(2) concentration in cell culture causes changes in both the FTIR and Raman spectra of embryonic stem cells. These results show that embryonic stem cells might be more sensitive to O(2) concentration when compared to mesenchymal stem cells. While vibrational spectroscopy could therefore be of potential use in identifying different populations of stem cells further work is required to better understand these differences.     

An Efficient N‐Arylation of Heterocycles with Aryl‐, Heteroaryl‐, and Vinylboronic Acids Catalyzed by Copper Fluorapatite

N‐Arylation of N‐containing heterocycles, such as pyrazoles, imidazoles, and benzimidazoles with aryl‐, heteroaryl‐, and vinylboronic acids was efficiently carried out by copper fluorapatite (CuFAP) catalyst in MeOH at room temperature under base‐free conditions. The N‐arylated heterocycles were isolated in good‐to‐excellent yields.     

Water-induced switching of β-structure to polyproline II conformation in the 4S-aminoproline polypeptide via H-bond rearrangement

4S-Aminoproline polypeptide 2 forms unusual β-structure in trifluoroethanol that switches to the polyproline II (PPII) form in aqueous medium, while 4R-aminoproline peptide 1 retains PPII form in both solvents. This first instance of a polyproline derivative showing a β-structure is attributed to competitive pH-dependent (4-NH(3)(+)/NH(2)) stereoelectronic effect (4R vs 4S) and the overriding importance of stereospecific intra/intermolecular H-bonding in (2,4)-cis-4S-aminoproline in contrast to (2,4)-trans-4R-aminoproline oligomers.