Oxidative Stability and Characterization of Quinoa Oil Extracted from Wholemeal and Germ Flours

Quinoa seeds are a source of lipids of great quality, and they highlight the content and composition of fatty acids and the presence of antioxidants such as tocopherols. Solvent extraction of quinoa oils was carried out from two matrices (wholemeal and germ flours), and in both cases, the extraction performance, physical–chemical characteristics, and oxidative stability were determined. Oxidative stability of the oil was assessed using an accelerated aging experiment under storage conditions at 60 °C for 12 days, in which the following parameters were measured: peroxide value, acid value, conjugated dienes and trienes, and scavenging radical capacity. Germ flour showed greater extraction yields (27.30 ± 0.15 g/100 g) compared to wholemeal (5.88 ± 0.02 g/100 g). Both oils presented similar physicochemical parameters, although the tocopherol content was higher in the oil extracted from germ flour (1354 vs. 735 mg/kg oil). At the same time, wholemeal oil showed a superior oxidative stability; hence, the wet milled process produces a minor impact on the compounds responsible for protection against lipid oxidation.     

Synthesis and photodynamic properties of amphiphilic A3B-phthalocyanine derivatives bearing N-heterocycles as potential cationic phototherapeutic agents

Unsymmetrically substituted A₃B-phthalocyanine derivatives bearing annulated 6-membered N-heterocycles, pyridine and pyrazine rings, were synthesized by the ring expansion reaction of boron(III) subphthalocyanine chloride. A geometrically constrained subphthalocyanine unit was reacted with a range of 1,2-phthalonitrile derivatives in presence of 8-diazabicyclo[5.4.0]undec-7-ene to form the A₃B-phthalocyanine. The reactions were carried out in DMSO/1-chloronaphthalene at 130-140 °C for 15 h. This synthetic strategy resulted in phthalocyanines in 37-42% yield that required only simple purification. Annulated 6-membered N-heterocycles were methylated to obtain cationic Zn(II)phthalocyanine derivatives. The spectroscopic and photodynamic properties of these photosensitizers were studied in N,N-dimethylformamide solution. Antifungal activity photoinduced by these compounds was evaluated in Candida albicans cellular suspensions. The results indicate that amphiphilic cationic phthalocyanines represent interesting agents with potential applications in photodynamic inactivation of microorganisms.     

Cu2ZnSnSe4 solar cells with 10.6% efficiency through innovative absorber engineering with Ge superficial nanolayer

In our recently published work, the positive effect of a Ge nanolayer introduced into the processing of Cu₂ZnSnSe₄ absorbers (CZTSe) was demonstrated. In this contribution, the complete optimization of this new approach is presented for the first time. Hence, the optimum Ge nanolayer thickness range is defined in order to achieve an improved performance of the devices, obtaining a record efficiency of 10.6%. By employing this optimized approach, the open‐circuit voltage (V_OC) is boosted for our pure selenide CZTSe up to 489 mV, leading to V_OC deficit among the lowest reported so far in kesterite technology. Additionally, two important effects related to the Ge are unambiguously demonstrated that might be the origin of the V_OC boost: the improvement of the grain size and the corresponding crystalline quality, and the interaction between Ge and Na that allows for dynamic control over the CZTSe doping. Finally, evidences pointing to the origin of the deterioration of devices properties for large Ge concentrations are presented. Copyright © 2016 John Wiley & Sons, Ltd.     

8.2% pure selenide kesterite thin‐film solar cells from large‐area electrodeposited precursors

Cu₂ZnSnSe₄ solar cell absorbers are synthesized by large‐area electrodeposition of metal stack precursors followed by selenization. A champion solar cell exhibits 8.2% power conversion efficiency, a new record for Cu₂ZnSnSe₄ solar cells prepared from electrodeposited metallic precursors. Significant improvements of device performance are achieved by the application of two etching procedures and buffer layer optimization. These results validate electrodeposition as a credible alternative to vacuum processes (sputtering, co‐evaporation) for earth‐abundant thin‐film solar cell fabrication at low cost. Copyright © 2015 John Wiley & Sons, Ltd.     

An Easy Method to Prepare D3 and C2‐TATP Crystals

D₃ and C₂ TATP structures interconvert at room temperature. Herein, an easy method to isolate both conformers is shown that consists of multiple recrystallization steps using different solvent and heating to boiling. Spectroscopic and physical measurements, such as Raman spectroscopy, X‐ray diffraction, and melting point analysis, showed that clear and opaque crystals, respectively, represent different conformations of TATP. Additionally, the transition energy between both conformers was estimated using the Raman shifts.     

Sometimes a Little Mango Goes a Long Way: a Rapid Approach to Assess How Different Shipping Systems Affect Fruit Commercial Quality

Mangoes are climacteric and highly perishable fruits and represent the most appreciated tropical fruits in the world for their special taste and aroma. Depending on the structure of the supply chain and on general environmental and technical factors, fruit picking may be anticipated or postponed within the frame time of fruit maturation stage. Hence, mangoes may be collected for long distance sea freight at the unripe green stage, while pre-ripened fruits, usually transported by air to shorten storage time, are harvested later and must be eaten within few days. In the present study, we assess the potential of an evaluation technique that combines conventional ripening measures with the new detection system of volatile compounds using the PTR-ToF-MS to obtain information on the fruit “eating” quality state. Fruits from the same mango cultivar and shipped from the same country with two alternative shipping systems were compared by analysing the evolution of their physicochemical characteristics and volatile organic compound (VOCs) profiles in time. By pooling the entire dataset together, it emerges that VOCs and physicochemical parameters can be used to separate the two types of transport and the two different ripening stages for the air-freighted fruits, while the sea-freighted fruits showed a rather static behaviour between the two sampling time. The two combined methods may provide a simple and fast tool to assess the presence of characters strongly attractive to mango consumers and in a broader context can be helpful in giving a better idea about the eating qualities of the commercialized products.     

A nickel tetra-coordinated complex as catalyst in heterogeneous hydrogenation

The [NiCl₂(NH₂(CH₂)₁₂CH₃)₂] complex supported on γ-Al₂O₃ produces a catalyst which is considerably more active and sulfur-resistant for the hydrogenation of cyclohexene carried out in mild conditions than a conventional catalyst obtained from acid solutions of NiCl₂ and even than the same complex unsupported. As determined by XPS, the active species is the complex itself, which is stable under the reaction conditions. The higher sulfur-resistance is attributed to electronic and geometrical effects. The catalyst system is considerably more resistant to poisoning with thiophene than with tetrahydrothiophene. © 1998 SCI     

Identification of proteins of the yeast protein map using genetically manipulated strains and peptide-mass fingerprinting

In this study we used genetically manipulated strains in order to identify polypeptide spots of the protein map of Saccharomyces cerevisiae. Thirty-two novel polypeptide spots were identified using this strategy. They corresponded to the product of 23 different genes. We also explored the possibilities of using peptide-mass fingerprinting for the identification of proteins separated on our gels. According to this strategy, proteins contained in spots are digested with trypsin and the masses of generated peptides are determined by matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS). The peptide masses are then used to search a yeast protein database for proteins that match the experimental data. Application of this strategy to previously identified polypeptide spots gave evidence of the feasibility of this approach. We also report predictions on the identities of nine unknown spots using MALDI-MS.