Optics clustered to output unique solutions: a multi-laser facility for combined single molecule and ensemble microscopy

Optics clustered to output unique solutions (OCTOPUS) is a microscopy platform that combines single molecule and ensemble imaging methodologies. A novel aspect of OCTOPUS is its laser excitation system, which consists of a central core of interlocked continuous wave and pulsed laser sources, launched into optical fibres and linked via laser combiners. Fibres are plugged into wall-mounted patch panels that reach microscopy end-stations in adjacent rooms. This allows multiple tailor-made combinations of laser colours and time characteristics to be shared by different end-stations minimising the need for laser duplications. This setup brings significant benefits in terms of cost effectiveness, ease of operation, and user safety. The modular nature of OCTOPUS also facilitates the addition of new techniques as required, allowing the use of existing lasers in new microscopes while retaining the ability to run the established parts of the facility. To date, techniques interlinked are multi-photon/multicolour confocal fluorescence lifetime imaging for several modalities of fluorescence resonance energy transfer (FRET) and time-resolved anisotropy, total internal reflection fluorescence, single molecule imaging of single pair FRET, single molecule fluorescence polarisation, particle tracking, and optical tweezers. Here, we use a well-studied system, the epidermal growth factor receptor network, to illustrate how OCTOPUS can aid in the investigation of complex biological phenomena.     

Isothermal and non‐isothermal crystallization of poly(L‐lactic acid)/poly(butylene terephthalate) blends

Isothermal and non‐isothermal crystallization kinetics of poly(l ‐lactic acid)/poly(butylene terephthalate) (PLLA/PBT) blends containing PLLA as major component is detailed in this contribution. PLLA and PBT are not miscible, but compatibility of the polymer pair is ensured by interactions between the functional groups of the two polyesters, established upon melt mixing. Crystal polymorphism of the two polyesters is not influenced by blending, as probed by wide‐angle X‐ray analysis. The addition of PLLA does not affect the temperature range of crystallization kinetics of PBT, nor the crystallinity level attained when the blends are cooled from the melt at constant rate. Conversely, PBT favors crystallization of the biodegradable polyester. The addition of PBT results in an anticipated onset of crystallization of PLLA during cooling at a fixed rate, with a sizeable enhancement of the crystal fraction. Isothermal crystallization analysis confirmed the faster crystallization rate of PLLA in the presence of PBT. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40372.     

Pullulan‐based films and coatings for food packaging: Present applications,emerging opportunities,and future challenges

Societal and industrial demands for lower environmental impact, cost effectiveness, and high‐performance goods and services are increasingly impacting the choice of technologies which are developed and deployed in consumer products. Like many other sectors, food packaging is moving to new technologies; the use of biopolymers is one of the most promising strategies toward an optimized use of traditional packaging materials (e.g., oil‐based plastics) without impairing the goal of extending shelf life. Among other food packaging materials, pullulan is attracting much attention due to its unique features. The goal of this review is to provide an overview of current and emerging applications of pullulan within the food packaging sector. In particular, the functional properties of interest for the food packaging industry will be discussed in light of the physicochemical attributes of this exopolysaccharide. Future challenges that may dictate the successful penetration of pullulan in the food packaging market are also outlined. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40539.     

Sphingolipids: Key Regulators of Apoptosis and Pivotal Players in Cancer Drug Resistance

Drug resistance elicited by cancer cells still constitutes a huge problem that frequently impairs the efficacy of both conventional and novel molecular therapies. Chemotherapy usually acts to induce apoptosis in cancer cells; therefore, the investigation of apoptosis control and of the mechanisms used by cancer cells to evade apoptosis could be translated in an improvement of therapies. Among many tools acquired by cancer cells to this end, the de-regulated synthesis and metabolism of sphingolipids have been well documented. Sphingolipids are known to play many structural and signalling roles in cells, as they are involved in the control of growth, survival, adhesion, and motility. In particular, in order to increase survival, cancer cells: (a) counteract the accumulation of ceramide that is endowed with pro-apoptotic potential and is induced by many drugs; (b) increase the synthesis of sphingosine-1-phosphate and glucosylceramide that are pro-survivals signals; (c) modify the synthesis and the metabolism of complex glycosphingolipids, particularly increasing the levels of modified species of gangliosides such as 9-O acetylated GD3 (αNeu5Ac(2-8)αNeu5Ac(2-3)βGal(1-4)βGlc(1-1)Cer) or N-glycolyl GM3 (αNeu5Ac (2-3)βGal(1-4)βGlc(1-1)Cer) and de-N-acetyl GM3 (NeuNH(2)βGal(1-4)βGlc(1-1)Cer) endowed with anti-apoptotic roles and of globoside Gb3 related to a higher expression of the multidrug resistance gene MDR1. In light of this evidence, the employment of chemical or genetic approaches specifically targeting sphingolipid dysregulations appears a promising tool for the improvement of current chemotherapy efficacy.     

New Insights on Plant Cell Elongation: A Role for Acetylcholine

We investigated the effect of auxin and acetylcholine on the expression of the tomato expansin gene LeEXPA2, a specific expansin gene expressed in elongating tomato hypocotyl segments. Since auxin interferes with clathrin-mediated endocytosis, in order to regulate cellular and developmental responses we produced protoplasts from tomato elongating hypocotyls and followed the endocytotic marker, FM4-64, internalization in response to treatments. Tomato protoplasts were observed during auxin and acetylcholine treatments after transient expression of chimerical markers of volume-control related compartments such as vacuoles. Here we describe the contribution of auxin and acetylcholine to LeEXPA2 expression regulation and we support the hypothesis that a possible subcellular target of acetylcholine signal is the vesicular transport, shedding some light on the characterization of this small molecule as local mediator in the plant physiological response.     

Algae through the looking glass

Microalgae are one of the most suitable subjects for testing the potentiality of light microscopy and image analysis, because of the size of single cells, their endogenous chromaticity, and their metabolic and physiological characteristics. Microscope observations and image analysis can use microalgal cells from lab cultures or collected from water bodies as model to investigate metabolic processes, behavior/reaction of cells under chemical or photic stimuli, and dynamics of population in the natural environment in response to changing conditions. In this paper we will describe the original microscope we set up together with the image processing techniques we improved to deal with these topics. Our system detects and recognizes in‐focus cells, extracts their features, measures cell concentration in multi‐algal samples, reconstructs swimming cell tracks, monitors metabolic processes, and measure absorption and fluorescent spectra of subcellular compartments. It can be used as digital microscopy station for algal cell biology and behavioral studies, and field analysis applications.     

Effect of Particle Size on Monometallic and Bimetallic (Au,Pd)/C on the Liquid Phase Oxidation of Glycerol

The influence of metal particle size of monometallic and bimetallic supported catalysts (Au, Pd, Au–Pd)/C was studied using as a model reaction the liquid phase oxidation of glycerol. By tuning the metal particle size from 2 to 16 nm a progressive decrease of activity and simultaneously an increase in the selectivity to sodium glycerate was observed. Moreover, the influence of the temperature was studied and it was found that by increasing the temperature, only with a large particle size the formed glycerate was retained and not over-oxidized to tartronate.     

Kinetic characterization of Prussian Blue-modified graphite electrodes for amperometric detection of hydrogen peroxide

Prussian Blue-modified graphite electrodes (G/PB) with electrocatalytic activity toward H₂O₂ reduction were obtained by PB potentiostatic electrodeposition from a mixture containing 2.5 mm FeCl₃ + 2.5 mm K₃[Fe(CN)₆] + 0.1 m KCl + 0.1 m HCl. From cyclic voltammetric measurements, performed in KCl aqueous solutions of different concentrations (5 × 10⁻²–1 m), the rate constant for the heterogeneous electron transfer (k _s) was estimated by using the Laviron treatment. The highest k_s value (10.7 s⁻¹) was found for 1 m KCl solution. The differences between the electrochemical parameters of the voltammetric response, as well as the shift of the formal potential, observed in the presence of Cl⁻ and NO₃⁻ compared to those observed in the presence of SO₄²⁻ ions, points to the involvement of anions in the redox reactions of PB. The G/PB electrodes showed a good electrochemical stability proved by a low deactivation rate constant (0.8 × 10⁻¹² mol cm² s⁻¹). The electrocatalytic efficiency, estimated as the ratio , was found to be 3.6 (at an applied potential of 0 mV vs. SCE; Γ = 5 × 10⁻⁸ mol cm⁻²) for a H₂O₂ concentration of 5 mm, thus indicating G/PB electrodes as possible H₂O₂ sensors.     

Torque‐rheometry investigation of model transreactions involving condensation polymers. I. Polyesters

The chemical transformations taking place when poly(ethylene terephthalate) (PET) or poly(ethylene naphthalate) (PEN) are blended in the melt with different low molar mass substances containing hydroxyl, carboxyl, or amine functional groups have been investigated as models of the transreactions, undergone by the polyesters in reactive blending operations. The polyester molecular weight changes caused by the alcoholysis, acidolysis, aminolysis, and esterolysis reactions have been monitored by torque‐rheometry, using a Brabender Plasticorder static mixer. The degradation of the polyesters by hydrolysis was also studied, under similar conditions, by the addition of a water‐releasing substance (wet polyamide‐6), and was shown to occur quite rapidly, although most of the added water was lost by flash vaporization caused by the high temperature of the polyester melt. It has been shown that the rate constants of the reactions leading to breakage of the inner ester bonds of the polyester macromolecules decrease in the following order: aminolysis (with aliphatic amines, either primary and secondary) > alcoholysis (with aliphatic alcohols) ≈ hydrolysis > acidolysis (with aromatic acids) ≥ acidolysis (with aliphatic acids) ? aminolysis (with aromatic amines) > alcoholysis (with phenols) ? esterolysis. POLYM. ENG. SCI. 46:139–152, 2006. © 2005 Society of Plastics Engineers     

Optimization of Improvable Flows by combining BAT Analysis and process simulation

This paper proposes a methodology to improve the sustainability of industrial processes combining two tools: BAT Analysis and process simulation. Both tools are jointly applied to identify the IF of the analyzed process, so that the most appropriate candidate techniques from an inventory can be selected. The selected alternatives are tested in different scenarios that are evaluated using simulation, which would determine the configuration that best improves the sustainability of the process. The combination of both tools in an integrated methodology will help decision makers to select the most sustainable configuration for a given process. The methodology is validated in a case study: a hydrogen production plant. After analysing several scenarios where different candidate techniques are implemented, results show that the IF identified can be highly improved when the appropriate combination of BAT is applied.