Effect of Acetic Acid on Saccharomyces Carlsbergensis ATCC 6269 Batch Ethanol Production Monitored by Flow Cytometry

Bioethanol produced from lignocellulosic materials has been considered a sustainable alternative fuel. Such type of raw materials have a huge potential, but their hydrolysis into mono-sugars releases toxic compounds such as weak acids, which affect the microorganisms' physiology, inhibiting the growth and ethanol production. Acetic acid (HAc) is the most abundant weak acid in the lignocellulosic materials hydrolysates. In order to understand the physiological changes of Saccharomyces carlsbergensis when fermenting in the presence of different acetic acid (HAc) concentrations, the yeast growth was monitored by multi-parameter flow cytometry at same time that the ethanol production was assessed. The membrane potential stain DiOC₆(3) fluorescence intensity decreased as the HAc concentration increased, which was attributed to the plasmic membrane potential reduction as a result of the toxic effect of the HAc undissociated form. Nevertheless, the proportion of cells with permeabilized membrane did not increase with the HAc concentration increase. Fermentations ending at lower external pH and higher ethanol concentrations depicted the highest proportions of permeabilized cells and cells with increased reactive oxygen species levels. Flow cytometry allowed monitoring, near real time (at-line), the physiological states of the yeast during the fermentations. The information obtained can be used to optimize culture conditions to improve bioethanol production.     

Seebeck rectification enabled by intrinsic thermoelectrical coupling in magnetic tunneling junctions

An intrinsic thermoelectric coupling effect in the linear response regime of magnetic tunneling junctions (MTJ) is reported. In the dc response, it leads to a nonlinear correction to Ohm's law. Dynamically, it enables a novel Seebeck rectification and second harmonic generation, which apply for a broad frequency range and can be magnetically controlled. A phenomenological model on the footing of the Onsager reciprocal relation and the principle of energy conservation explains very well the experimental results obtained from both dc and frequency-dependent transport measurements performed up to GHz frequencies. Our work refines previous understanding of magnetotransport and microwave rectification in MTJs. It forms a new foundation for utilizing spin caloritronics in high-frequency applications.     

Connection between the upper and lower energy regions of the potential energy surface of the ground electronic state of the HSO2 system

The importance of the HSO(2) system in atmospheric and combustion chemistry has motivated several works dedicated to the study of associated structures and chemical reactions. Nevertheless, controversy still exists about a possible connection between the upper and lower energy regions of the potential energy surface (PES) for the ground electronic state of the system. Very recently, a path to connect these regions was proposed based on studies at the CASPT2/aug-cc-pV(T+d)Z level of calculation but the small energy difference between some of the transitions states along that path suggested the necessity of calculations at a higher level of theory. In the present work, we report a CCSD(T)/aug-cc-pV(T+d)Z study of the stationary states associated to the proposed connection path, including assessment of the most reliable complete basis set (CBS) extrapolation scheme for the system. Among the new features, the present calculations show that there are no structures corresponding to the HSO(2)(b) minimum and the TS3 saddle point obtained at the CASPT2 level and that the connection path between the upper and lower energy regions of the PES for the ground electronic state involves only one transition state and most probably more than one electronic state.     

Fluorene: An extended experimental thermodynamic study

This work reports new experimental thermodynamic results on fluorene. Vapor pressures of both crystalline and liquid phases were measured using a pressure gauge (capacitance diaphragm manometer) and Knudsen effusion methods over a wide temperature range (292.20 to 412.16) K yielding accurate determination of enthalpy and entropy of sublimation and of vaporization. The enthalpy of sublimation was also determined using Calvet microcalorimetry. The enthalpy of fusion was derived from vapor pressure results and from d.s.c. experiments. Static bomb calorimetry was used to determine the enthalpy of combustion of fluorene from which the standard enthalpy of formation in the crystalline phase was calculated. The enthalpy of formation in the gaseous phase was calculated combining the result derived for the crystalline phase with the enthalpy of sublimation.     

Synthesis and Characterization of the Monomer 2,2′ diallylbisphenol-A (ABFA) for obtaining Proton Exchange Membranes based on Crosslinked Sulphonated Poly(Arylene ether sulphone)s

Summary: In the present work, a methodology of synthesis and characterization of the monomer 2,2′ diallylbisphenol-A (ABFA) was developed, aiming at getting a precursor, with adequate purity, for obtaining cross-linked membranes based on sulphonated poly(arylene ether sulphone)s. The monomer synthesis involved the synthesis of 2,2′ bis(4-allyloxiphenyl)propane (Bisphenol-A, diallyl ether - BFAAE), from Bisphenol-A (BFA), followed by Claisen rearrangement of BFAAE, for the production of the target compound 2,2′ diallylbisphenol-A (ABFA). All the compounds, reagent BFA and obtained products, intermediate product BFAAE and final product ABFA, were characterized by FTIR (Fourier Transform infrared spectroscopy), TGA (Thermo-gravimetric analysis) and HPLC (High-performance liquid chromatography). The compound BFAAE was obtained with a yield of 94.5% and a purity of 97.3%, the latter characterized by TGA and by HPLC. The structure of the product was confirmed by FTIR. The thermal Claisen rearrangement process was conducted by using Differential Scanning Calorimetry (DSC) technique, from a factorial experiment planning, with two factors and three levels, with temperature and time being the variables. The above cited techniques were used for monitoring the Claisen rearrangement and for the characterization of the final product. The best results yield ABFA purity between 85 and 90%, approximately, for 220 °C/60min, 230 °C/30min and 210 °C/90min conditions. The obtained results suggest that, in the studied range, polymerization and degradation of the monomer ABFA occur, simultaneously to its formation.     

Determination of selenium in bread-wheat samples grown under a Se-supplementation regime in actual field conditions

Selenium is an essential micronutrient for humans and animals, yet it is deficient in at least one billion people worldwide. Plants and plant-derived products transfer the soil-uptaken selenium to humans; therefore, the cultivation of plants enriched in selenium can be an effective way to improve the selenium status on humankind. This paper focuses on determining the ability of bread wheat to accumulate selenium after supplementation. One of the methods for supplementing this element in plants is foliar application with selenium solutions. These supplemented crop of wheat samples—bread wheat; Triticum aestivum L.—were used to determine if there is an increase of selenium content in cereal grains by comparing them with cereals cultivated in 2009 and harvested in 2010 with no supplementation. The experiments were done using sodium selenate and sodium selenite at three different selenium concentrations: 4, 20 and 100 g per hectare. Total Se is assessed by cyclic neutron activation analysis (CNAA), through short irradiations on the fast pneumatic system (SIPRA) of the Portuguese Research Reactor (RPI-ITN). The short-lived nuclide ^77mSe, that features a half-lifetime of 17.5 s, was used to determine the Se content in SIPRA. The experiment was successful, since the selenium concentration increased in the cropped grains and reached values up to 35 times the non-supplemented ones.     

catena‐Poly­[fac‐tri­chloro­methyl­tin(IV)‐μ‐[meso‐1,2‐bis­(phenyl­sulfinyl)­ethane‐O:O′]]

In the title compound, [SnCl₃(CH₃)(C₆H₅SOCH₂)₂]_n, the octahedral Sn^IV centres are bridged by meso‐1,2‐bis­(phenyl­sulfinyl)­ethane ligands forming infinite chains along the [100] direction.     

Effect of Ylang-Ylang (Cananga odorata Hook. F. & Thomson) Essential Oil on Acute Inflammatory Response In Vitro and In Vivo

The aim of this study is to evaluate the phytochemical profile, oral acute toxicity, and the effect of ylang-ylang (Cananga odorata Hook. F. & Thomson) essential oil (YEO) on acute inflammation. YEO was analyzed by gas chromatography/mass spectrometry. For in vitro tests, YEO was assessed using cytotoxicity, neutrophil chemotaxis induced by N-formyl methionyl leucyl phenylalanine (fMLP), and phagocytic activity tests. YEO was orally administered in zymosan-induced peritonitis, carrageenan-induced leukocyte rolling, and adhesion events in the in situ microcirculation model and in carrageenan-induced paw edema models. YEO (2000 mg/kg) was also tested using an acute toxicity test in Swiss mice. YEO showed a predominance of benzyl acetate, linalool, benzyl benzoate, and methyl benzoate. YEO did not present in vitro cytotoxicity. YEO reduced the in vitro neutrophil chemotaxis induced by fMLP and reduced the phagocytic activity. The oral treatment with YEO reduced the leukocyte recruitment and nitric oxide production in the zymosan-induced peritonitis model, reduced rolling and adherent leukocyte number induced by carrageenan in the in situ microcirculation model, and reduced carrageenan-induced edema and mechanical hyperalgesia. YEO did not present signs of toxicity in the acute toxicity test. In conclusion, YEO affected the leukocyte activation, and presented antiedematogenic, anti-hyperalgesic, and anti-inflammatory properties.