Reaction pathway to Cu2ZnSnSe4 formation in CdI2

Journal of Thermal Analysis and Calorimetry - We investigated various possible chemical interactions between individual precursor compounds (ZnSe, SnSe, and CuSe) and CdI2 as a flux material used...     

Cu2ZnSnSe4 formation and reaction enthalpies in molten NaI starting from binary chalcogenides

The present study deals with chemical reactions and enthalpies during the synthesis of Cu₂ZnSnSe₄ (CZTSe) from CuSe, SnSe, and ZnSe in molten NaI as flux material in closed degassed ampoules. Differential thermal analysis (DTA) at heating rates 5 °C min^?1 and cooling rates 10 °C min^?1 were used for the determination of temperatures of phase transitions and/or chemical reactions. XRD and Raman analyses confirmed that the formation of CZTSe starts already at 380 °C after the melting of Se that deliberates from the transformation of CuSe to Cu_1.8Se, and the CZTSe formation process impedes to a great extent due to the presence of solid NaI. After the melting of NaI, the formation of CZTSe is completed. For the determination of enthalpy values, the calibration with pure NaI was performed. The thermal effects and enthalpies were compared with the available known thermodynamical values. The specific enthalpy of exothermic Cu₂ZnSnSe₄ formation at 661 °C in NaI ?36 ± 3 kJ mol^?1 was determined experimentally for the first time. Ternary compound Na₂SnSe₃ was formed during the synthesis process. NaI·2H₂O, if present in NaI, was found to be a critical issue in the synthesis process of CZTSe monograin powders in molten NaI—it gave rise to the formation of oxygen-containing by-products Na₂SeO₄ and Na₂Cu(OH)₄. The complete dehydration of NaI·2H₂O at T ≤ 70 °C in vacuum is necessary to avoid the formation of oxygen-containing compounds.     

Three Diverse Granule Preparation Methods for Proteomic Analysis of Mature Rice (Oryza sativa L.) Starch Grain

Starch is the primary form of reserve carbohydrate storage in plants. Rice (Oryza sativa L.) is a monocot whose reserve starch is organized into compounded structures within the amyloplast, rather than a simple starch grain (SG). The mechanism governing the assembly of the compound SG from polyhedral granules in apposition, however, remains unknown. To further characterize the proteome associated with these compounded structures, three distinct methods of starch granule preparation (dispersion, microsieve, and flotation) were performed. Phase separation of peptides (aqueous trypsin-shaving and isopropanol solubilization of residual peptides) isolated starch granule-associated proteins (SGAPs) from the distal proteome of the amyloplast and the proximal ‘amylome’ (the amyloplastic proteome), respectively. The term ‘distal proteome’ refers to SGAPs loosely tethered to the amyloplast, ones that can be rapidly proteolyzed, while proximal SGAPs are those found closer to the remnant amyloplast membrane fragments, perhaps embedded therein—ones that need isopropanol solvent to be removed from the mature organelle surface. These two rice starch-associated peptide samples were analyzed using nano-liquid chromatography–tandem mass spectrometry (Nano-HPLC-MS/MS). Known and novel proteins, as well as septum-like structure (SLS) proteins, in the mature rice SG were found. Data mining and gene ontology software were used to categorize these putative plastoskeletal components as a variety of structural elements, including actins, tubulins, tubulin-like proteins, and cementitious elements such as reticulata related-like (RER) proteins, tegument proteins, and lectins. Delineating the plastoskeletal proteome begins by understanding how each starch granule isolation procedure affects observed cytoplasmic and plastid proteins. The three methods described herein show how the technique used to isolate SGs differentially impacts the subsequent proteomic analysis and results obtained. It can thus be concluded that future investigations must make judicious decisions regarding the methodology used in extracting proteomic information from the compound starch granules being assessed, since different methods are shown to yield contrasting results herein. Data are available via ProteomeXchange with identifier PXD032314.     

Reaction pathway to CZTSe formation in CdI2

The thermal decomposition of cotton and hemp fibers was studied after mild alkaline treatments with tetramethyl-, tetraethyl- and tetrabutylammonium hydroxides with the goal of modeling the chemical activation during carbonization of cellulosic fibers. The thermal decomposition was studied by thermogravimetry/mass spectrometry and pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). The treated samples decomposed in two temperature ranges during heating in the thermobalance. At lower temperature, tetraalkylammonium hydroxides (TAAH) ionically bonded to the cellulose molecules were decomposed; moreover, the alkaline agents initiated the partial decomposition of cellulose. Those fiber segments, which were not accessible for TAAH, decomposed at similar temperatures as the original cotton and hemp samples. It is known that quaternary ammonium hydroxides swell the cellulosic fibers; however, the results of this study proved that there was a chemical interaction between the alkaline swelling agents and cotton or hemp fibers at rather low temperatures (200–300 °C). The evolved products indicated that the alkaline chemicals reacted with the cellulose molecules and alkylated compounds were formed. This observation was confirmed by thermochemolysis experiments carried out by Py–GC/MS using tetramethylammonium hydroxide reagent. The thermochemolysis experiments under mild conditions resulted in the methylation of the glucoside units and levoglucosan, and no peeling reactions of the sugar units were observed as during strong alkaline conditions described in the literature.

     

Plant essential oils and mastitis disease: their potential inhibitory effects on pro-inflammatory cytokine production in response to bacteria related inflammation

This paper highlights the role of plant volatile organic compounds, found in essential oils, for the treatment of bacteria related inflammation. This report is focused on tea tree oil, particularly its main compound terpinen-4-ol. Analysis of the published literature shows that many essential oils have significant antibacterial, antifungal and anti-inflammatory effects. Some of their major components, such as terpinen-4-ol, act by inhibiting pro-inflammatory cytokine expression while stimulating production of anti-inflammatory cytokines. Such observations may be exploited to encourage biotherapy against mastitis. The use of synthetic antibiotics is being increasingly discouraged because their presence in dairy milk may have potential downstream effects on population health and the agri-food chain. In the context of inflammation and related mammalian responses, understanding the interplay between volatile organic compounds, especially terpinen-4-ol, and cytokines during bacteria related inflammation should clarify their mode of action to control mastitis.