Small Amounts Of Mono Research Articles

Investigation into Anion Effects on the Bulk and Interfacial Solvation Structure for Multivalent Ion Batteries

Zinc ion batteries (ZIB) are attractive because of the relative abundance of Zn as a core earth element, a higher volumetric energy density compared to lithium metal and it is cost effective. Despite this promise, a general lack of fundamental understanding of the electrode-electrolyte interface in ZIB, and multivalent (MV) ion technologies more broadly, hinders their wide scale deployment. In particular, the solvation structure of aqueous and non-aqueous electrolytes plays a critical role in promoting the necessary intermolecular charge transfer interactions to drive reversible plating/stripping at the metal anode. Here we examine the dynamics of the bulk and interfacial solvation structure to uncover differences in the bulk vs. the interfacial speciation as a function of anion chemistry in hopes to develop new design principles for new electrolyte development in ZIB and MV technologies. Utilizing Raman spectroscopy to probe the bulk solvation structures of Zn-based electrolytes containing one anion such as SO4 2-, bis-trifluoromethane sulfonimide (TFSI-) and trifluoromethanesulfonate (triflate, OTf-), we find three solvation environments present; a main feature corresponding to the “free” anion breathing mode and, in some cases, small amounts of mono- or bidentate contact ion pairs (CIPs). In some cases, introduction of co-anions (i.e., halides, X = Cl-, Br-, I-) results in significant extra intensity on the low frequency side of the overall Raman peak envelope that does not correspond with solvation structures observed in the single anion electrolytes. First principles density functional theory (DFT) calculations indicate the additional vibrational mode corresponds to a mixed anion CIP, suggesting anion-anion interactions can induce nominally dissociated anions to coordinate the cation in ways they otherwise would not. Raman and DFT analysis of Mg-based electrolytes indicate similar mixed anion CIP structures are formed, indicating similar solvation effects are active in other MV systems. Preliminary measurements utilizing shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERs) will also be discussed as a means of developing in situ understanding of the evolution of interfacial solvation and surface chemistry during the stripping/plating process. Overall, these results point to new possibilities in controlling the multivalent cation solvation structures present in the bulk and at the interface. This will aid in the development of highly reversible electrolytes that are stable against both divalent metal anodes and high voltage cathodes.

Hydrogermylation of allylsilanes and -germanes

The reactions of hydrogermylation of allylsilanes and -germanes R3MAll (M = Si, Ge; R = Cl, EtO, Me) by hydridgermanes R3GeH (R = Cl, Me) and trichlorogermane ether 2Et2O·HGeCl3 were studied. It has been established that small amounts of mono- (β- and γ-adducts) and double germylation products and, mainly, polymers are formed in reactions with ether. During hydrogermylation of Me3SiAll with trichlorogermane, insignificant amounts of β-adduct were recorded, but mainly in the entire series of experiments with Cl3GeH, γ-adducts are formed. In the catalytic reactions of allylsilanes and -germanes with trimethylgermane, exclusively γ-adducts are formed regardless of the framing of silicon and germanium atoms. A scheme of the possible course of the studied reactions is proposed. The identification of synthesized compounds was carried out using the methods of gas-liquid chromatography, 1Н, 13С NMR spectroscopy and chromatography-mass spectrometry

Modeling of vegetable oils cloud point, pour point, cetane number and iodine number from their composition using genetic programming

Vegetable oils (VOs) are composed of 90–98% of triglycerides, i.e. esters composed of three fatty acids and glycerol, and small amounts of mono- and di-glycerides. Due to their physico-chemical properties, VOs have been considered for uses especially in large ships, in stationary engines and low and medium speed diesel engines, in pure form or in blends with fuel oil, diesel, biodiesel and alcohols. There are about 350 VOs with potential as fuel sources, and for most of them, physico-chemical properties values have not yet been measured. In this context, regression models using only VOs fatty acid composition are very useful. In the present paper, regression analysis of VOs cloud point (CP), pour point (PP), cetane number (CN) and iodine number (IN) as a function of saturated and unsaturated fatty acids is conducted. The study is done by using 4 experimental databases including 88 different data of VOs. Concerning the regression technique, genetic programming (GP) has been chosen. The cost function of GP is defined to minimize the Mean Absolute Error (MAE) between experimental and predicted values of each property. The resulting GP models consisting of terms including saturated and unsaturated fatty acids reproduce correctly the dependencies of all four properties on those acids. And they are validated by showing that their results are in good agreement to the experimental databases. In fact, MAE values of the proposed models with respect to the databases for CP, PP, CN and IN are lower than 4.51 °C, 4.54 °C, 3.64 and 8.01, respectively.

Esterification of Crude “Macaúba” Oil (Acrocomia aculeata) Using Amberlyst 15 as a Heterogeneous Catalyst Performed in Reactor Parr

The “macauba” (Acrocomia aculeata) is a Brazilian palm tree that represents a promising alternative for the production of biodiesel. The kernel and the almond of the fruits are rich in oil. Its oil has interesting physicochemical characteristics for the production of biodiesel. It consists mainly of triacylglycerols and small amounts of mono and diacylglycerols, and it has a high content of unsaturated fatty acids, mainly oleic acid. However, it has a high content of free fatty acids which prevents reactions with basic catalysis for biodiesel production. The use of solid catalysts to improve the biodiesel production processes is considered as a promising alternative in this case. In addition, the solid catalysts have the highest reaction rate when compared to acid catalysts. The aim of this study was to obtain ethyl esters of crude oil from A. aculeate withhigh acid value (45.3 mg KOH g-1), using heterogeneous catalyst, with low reaction temperature. Thereactions were done in an under-pressurized Parr 4843 reactor. For the reaction, the factorial design is 2 elevated to 2 and response surface methodology was used. The variables studied were: temperature (T), molar ratio (MR) (ethanol:oil) and catalyst Amberlyst 15 (C, wt%). The response was obtained into yield (%) of ethyl esters and conversion (%) of free fatty acid, which were quantified by gas chromatography (GC). The response surface indicated the reaction at temperature 80-100 °C, molar ratio ethanol:oil 9.0:1 and catalyst 9- 11 wt% presented an yield in 32.8% of fatty acid ethyl esters (FAEE) and 72.0% of conversion, with 48.8 of selectivity index. The Amberlyst 15 catalyst showed little selectivity for yield in terms of FAEE, but a greater conversion of free fatty acids (FFAs) to the respective ethyl esters occurred. The surface response graph indicated that the reaction medium at temperature 60-70 °C, ethanol:oil 8.0:1-9.0:1 and catalyst 2-4% wt provided 83.8% of FFA conversion. This result is expected for oils with high FFA content, since conversion occurs at lower temperatures, while good yields occur at elevated temperatures.

Seed α-D-Galactosides of Selected Vicia Species and Enzymes Involved in Their Biosynthesis

We compared the soluble carbohydrate composition of seeds of ten wild and cultivated species of the genus Vicia. In some Vicia species (V. angustifolia, V. grandiflora, V. sativa, V. sepium) they contained only raffinose family oligosaccharides (RFOs) and in others also D-pinitol and its α-D-galactosides. In terms of galactosyl pinitol composition they were divided into three groups: those accumulating small amounts of mono-, di-, tri-galactosyl pinitol A (GPA, ciceritol and TGPA, respectively) and unknown compound (V. sylvatica and V. hirsuta); those accumulating more ciceritol than TGPA (V. tetrasperma and V. villosa); and those accumulating more TGPA than ciceritol (V. cracca and V. tenuifolia). The differences in the activity of galactosyltransferases engaged in RFOs and galactosyl pinitol synthesis confirmed this classification. Seeds of V. angustifolia, naturally accumulating only RFOs, showed an ability to accumulate exogenously applied D-pinitol or D-chiro-inositol and to form the respective α-D-galactosyl cyclitols. Levels of synthesized galactosides depended on the type and concentration of cyclitol in the feeding solution, and seed maturation stage. However, even a high level of D-pinitol or D-chiro-inositol in the feeding solution caused accumulation of only small amounts of mono- and di-galactosyl pinitols, or tri-galactosyl D-chiro-inositol in seeds of V. angustifolia. Enhanced synthesis of galactosyl cyclitols, mainly mono- and di-galactosides of D-chiro-inositol (fagopyritols), clearly reduced production of verbascose. We suggest that exogenously applied free cyclitols inhibit biosynthesis of tri- and di-galactosides and/or cause substrate competition in enzymes of Vicia species.

β-Agostic Silylamido and Silyl-Hydrido Compounds of Molybdenum and Tungsten

Reactions of bis(imido) compounds (RN)(2)Mo(PMe(3))(n) (n = 2, R = (t)Bu; n = 3, R =2,6-dimethylphenyl (Ar') and 2,6-diisopropylphenyl (Ar)) and (RN)(2)W(PMe(3))(3) (R = 2,6-dimethylphenyl and 2,6-diisopropylphenyl) with silanes afford four types of products: the beta-agostic silylamido compounds (RN)(eta(3)-RN-SiR'(2)-H...)MCl(PMe(3))(2) (M = Mo and W), mono(imides) (RN)MCl(2)(PMe(3))(3) (M = Mo and W), silyl hydride bis(imido) derivative (ArN)(2)W(PMe(3))(H)(SiMeCl(2)), and Si-Cl...W bridged product (ArN)(eta(2)-ArN-SiHMeCl-Cl...)WCl(PMe(3))(2). Reactions of molybdenum compounds (RN)(2)Mo(PMe(3))(m) (m = 2 or 3) with mono- and dichlorosilanes HSiCl(n)R'(3-n) (R' = Me, Ph; n = 1,2) afford mainly the agostic compounds (RN)(eta(3)-RN-SiR'(2)-H...)MoCl(PMe(3))(2), accompanied by small amounts of mono(imido) derivatives (RN)MoCl(2)(PMe(3))(3). In contrast, the latter compounds are the only transition metal products in reactions with HSiCl(3), the silicon co-product being the silanimine dimer (RNSiHCl)(2). The reaction of (ArN)(2)W(PMe(3))(3) with HSiCl(2)Me under continuous removal of PMe(3) affords the silyl hydride species (ArN)(2)W(PMe(3))(SiMeCl(2))H, characterized by NMR and X-ray diffraction. This product is stable in the absence of phosphine, but addition of catalytic amounts of PMe(3) causes a fast rearrangement into the Si-Cl...W bridged product (ArN)(eta(2)-ArN-SiHMeCl-Cl...)WCl(PMe(3))(2). The mechanism of silane addition to complexes (RN)(2)Mo(PMe(3))(n) has been elucidated by means of density functional theory calculations of model complexes (MeN)(2)Mo(PMe(3))(n) (n = 1-3). Complex (MeN)(2)Mo(PMe(3))(2) is found to be the most stable form. It undergoes facile silane-to-imido addition reactions that afford silylamido hydride complexes stabilized by additional Si...H interactions. The ease of this addition increases from HSiMe(2)Cl to HSiCl(3), consistent with experimental observations. The most stable final products of silane addition are the agostic complexes (MeN)(eta(3)-MeN-SiR(2)-H...)MoCl(PMe(3))(2) (R(2) = Me(2), MeCl, Cl(2)) and Cl-bridged silylamido complexes (MeN)(eta(2)-MeN-SiRH-Cl...)MoCl(PMe(3))(2) (R = Me or Cl). In the case of HSiMeCl(2) addition the former is the most stable, but for HSiCl(3) addition the latter is the preferred product. In all cases, the isomeric silyl hydride species (MeN)(2)Mo(PMe(3))(H)(SiClR(2)) are less stable by about 6 kcal mol(-1). Silane additions to the imido ligand of the tris(phosphine) (MeN)(2)Mo(PMe(3))(3) afford octahedral silylamido hydride derivatives. The different isomers of these addition products are destabilized relative to (MeN)(2)Mo(PMe(3))(3) only by 7-24 kcal mol(-1) (for the HSiMe(2)Cl additions), but since the starting tris(phosphine) is 14.8 kcal mol(-1) less stable than (MeN)(2)Mo(PMe(3))(2), silane addition to the latter is a more preferred pathway. A double phosphine dissociation pathway via the species (MeN)(2)Mo(PMe(3)) was ruled out because this complex is by 24.7 kcal mol(-1) less stable than (MeN)(2)Mo(PMe(3))(2).

Axoneme‐dependent tubulin modifications in singlet microtubules of the Drosophila sperm tail

Drosophila melanogaster sperm tubulins are posttranslationally glutamylated and glycylated. We show here that axonemes are the substrate for these tubulin C-terminal modifications. Axoneme architecture is required, but full length, motile axonemes are not necessary. Tubulin glutamylation occurs during or shortly after assembly into the axoneme; only glutamylated tubulins are glycylated. Tubulins in other testis microtubules are not modified. Only a small subset of total Drosophila sperm axoneme tubulins have these modifications. Biochemical fractionation of Drosophila sperm showed that central pair and accessory microtubules have the majority of poly-modified tubulins, whereas doublet microtubules have only small amounts of mono- and oligo-modified tubulins. Glutamylation patterns for different beta-tubulins experimentally assembled into axonemes were consistent with utilization of modification sites corresponding to those identified in other organisms, but surrounding sequence context was also important. We compared tubulin modifications in the 9 + 9 + 2 insect sperm tail axonemes of Drosophila with the canonical 9 + 2 axonemes of sperm of the sea urchin Lytichinus pictus and the 9 + 0 motile sperm axonemes of the eel Anguilla japonica. In contrast to Drosophila sperm, L. pictus sperm have equivalent levels of modified tubulins in both doublet and central pair microtubule fractions, whereas the doublets of A. japonica sperm exhibit little glutamylation but extensive glycylation. Tubulin C-terminal modifications are a prevalent feature of motile axonemes, but there is no conserved pattern for placement or amount of these

Metabolism of melphalan by rat liver microsomal glutathione S-transferase

One of the major problems in the treatment of human cancer is the phenomenon of drug resistance. Increased glutathione (γ-glutamylcysteinylglycine, GSH) conjugation (inactivation) due to elevated level of cytosolic glutathione S-transferase (GST) is believed to be an important mechanism in tumor cell resistance. However, the potential involvement of microsomal GST in the establishment of acquired drug resistance (ADR) remains uncertain. In our experiments, a combination of liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was employed for structural characterization of the resulting conjugates between GSH and melphalan, one of the alkylating agents. The spontaneous reaction of 1 mM melphalan with 5 mM GSH at 37 °C in aqueous phosphate buffer for 1 h gave primarily the monoglutathionyl and diglutathionyl melphalan derivatives, with small amounts of mono- and dihydroxy melphalan derivatives. We demonstrated that rat liver microsomal GST presented a strong catalytic effect on the reaction as determined by the increase of monoglutathionyl and diglutathionyl melphalan derivatives and the decrease of melphalan. We showed that microsomal GST was activated by melphalan in a concentration- and time-dependent manner. Microsomal GST which was stimulated approximately 1.5-fold with melphalan had a stronger catalytic effect. Thus microsomal GST may play a potential role in the metabolism of melphalan in biological membranes, and in the development of ADR.

Systemic Induction of Allelochemicals in Glanded and Glandless Isogenic Cotton by Spodoptera exigua Feeding

Induction of systemic resistance to feeding of beet armyworm, Spodoptera exigua, was investigated in two isogenic lines of Stoneville 213 cotton, Gossypium hirsutum, that differed in the presence of pigment glands. In laboratory bioassays, larvae strongly preferred to feed on glandless cotton plants when presented a choice between undamaged terminal leaves of undamaged glanded and glandless plants. Feeding damage inflicted by S. exigua larvae on the two oldest leaves of glanded plants seven days prior to feeding bioassays caused larvae to prefer by 33-fold the undamaged terminal foliage from undamaged plants compared to that from damaged plants. Feeding damage on glandless plants caused only a 2.6-fold greater preference for terminal foliage from undamaged plants over foliage from previously damaged plants. Extracts of terminal foliage from glanded cotton damaged seven days earlier had significantly greater quantities of terpenoid aldehydes (hemigossypolone, gossypol, and heliocides) than did foliage from undamaged glanded plants. Terpenoid aldehydes were undetectable in extracts of both undamaged and previously damaged glandless plants. The profile of volatile compounds collected from the headspace of mechanically damaged terminal leaves of undamaged glanded and glandless plants differed. Both cotton isolines released large quantities of lipoxygenase products (hexenyl alcohols, acetates, and butyrates), but glandless plants released only small amounts of mono- and sesquiterpenes compared to glanded plants. Glandless plants damaged seven days prior to volatile collection released significantly greater quantities of lipoxygenase products, β-ocimene, and α- and β-farnesene than did undamaged glandless plants. Previously damaged glanded plants released significantly greater quantities of all mono- and sesquiterpenes and hexenyl acetates and butyrates, but not alcohols. The relative importance of volatile compounds versus terpenoid aldehydes in induced feeding deterrence in cotton to S. exigua larvae is still unclear.

Autoaccelerative diazo coupling with calix[4]arene: substituent effects on the unusual co-operativity of the OH groups

Diazo coupling between calix[4]arene and five substituted benzenediazonium ions in tetrahydrofuran at 5 °C in the presence of pyridine afforded the tetrasubstituted calix[4]arenes as main products and small amounts of mono-, di- and tri-substituted calix[4]arenes even in the presence of unchanged calix[4]arene: the unusual autoaccelerative substitution reaction is attributed to the specific hydrogen-bonding effect among the calix[4]arene OH groups. The products were applied as new ‘chromophoric calix[4]arenes’, which selectively recognised Li+.

Lipid composition of millet (Pennisetum americanum) seeds

AbstractThe composition of lipids extracted from a sample of millet seeds by each of 8 solvent systems is reported. Lipid components were separated by silicic acid column and thin layer chromatography (TLC) and quantitated by analysis of fatty acid methyl esters by gas liquid chromatography (GLC), with heptadecanoic acid as internal standard. Best results were obtained by extraction with hot water‐saturated butanol. Lipids extracted amounted to 7.2% of the seed dry weight and consisted of 85% neutral lipids, 12% phospholipids and 3% glycolipids. Neutral lipids contained mostly (85%) triacylglycerols and small amounts of mono‐ and diacylglycerols, sterols and free fatty acids. Sterols consisted of campesterol, stigmasterol and 2 unidentified sterols, occurring in the same proportions in free and esterified forms. Ten glycolipid and 10 phospholipid components were separated and characterized. Contrary to previously published observations, lysophosphatidylcholine was the major phospholipid (42%) in millet seeds; smaller amounts of phosphatidylcholine (24%), lysophosphatidylethanolamine (21%) and trace amounts of phosphatidylglycerol, phosphatidic acid, phosphatidylserine and phosphatidylinositol also were present. The major glycolipids were esterified sterol glycoside, sterol glycoside, monogalactosyldiacylglycerol, digalactosyldiacylglycerol and cerebrosides (ceramide monohexosides).

Triterpeneglycosides as Inhibitors of Fungal Growth and Metabolism 8. Induced Leakage of Nucleotide Materials

AbstractAddition of aescin to mycelia of Ophiobolus graminis and Neurospora crassa induced leakage of ribonucleotide material together with pentose phosphate or pentose.In O. graminis a rapid release of mono‐ and dinucleotides together with nucleosides and pentose occurred. In addition some oligonucleotides were released during the first 30 min of the treatment. A slow leakage of polynucleotides was also observed.In N. crassa aescin induced only slight leakage during the first hour, and the mono‐ and dinucleotide leakage was actually decreasing. From that time on, however, a rapid release of mono‐ and dinucleotides together with nucleosides and pentose phosphate or pentose was observed. Only small amounts of poly‐ and oligonucleotides leaked and the cell content of oligonucleotides seemed to be released only during the last hour of the treatment period.In Aspergillus niger, which was insensitive to the inhibitor, aescin only induced leakage of pentose or pentose phosphate and small amounts of mono‐ and dinucleotides.Loss of viability in mycelia of O. graminis and N. crassa seemed to be correlated with the loss of oligonucleotides from the cells.

Biochemical and Physiological Studies of Certain Ticks (Ixodoidea). Phospholipid and Sterol Patterns in Biological Fluids of Nymphal and Adult Hyalomma (H.) Dromedarii Koch and H. (H.) Anatolicum Excavatum Koch (Ixodidae)1

In hemolymph, gut, and molting fluids of nymphal and adult Hyalomma (H.) dromedarii (Koch) and H. (H.) anatolicum excavatum (Koch) (family Ixodidae), the lipid classes were phospholipid (PL), cholesterol (CH), free fatty acids, triglycerides, and sterol esters, together with small amounts of mono- and diglycerides. PL, total sterols and percent CH contents were analyzed during specific physiological states of tick development. Hemolymph free sterols consisted exclusively of cholesterol. When fully fed nymphs and females dropped from the host, their gut PL and sterol concentrations were substantially higher than in host rabbit plasma and whole blood. Lipid concentrations on the day engorged nymphs dropped from the host, molting day and the female dropping day changed more consistently than for the other states. The results suggest that ticks have no requirement, and therefore lack the capacity, for sterol biosynthesis.

The fatty acids of some marine crustaceans

The lipids of one species of epipelagic euphausiid and six species of mesopelagic decapods from the eastern-North Atlantic have been shown by thin-layer chromatography to consist mainly of triglyceride, with small amounts of mono- and di-glyceride, sterol, sterol ester and phospholipid. The generally low level of lipid (2–5% wet weight) suggests that lipids have no buoyancy function in these animals. Gas-liquid chromatography showed that the fatty acid composition of Euphausia brevis differed from that of the decapods in having much less octadecaenoic acid (18:1) and more eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6). The principal differences in the fatty acid composition of the decapods were in their contents of octadecaenoic, eicosaenoic (20:1) and docosaenoic (22:1) acids, but no correlation was found between fatty acid composition and species. A specimen of Acanthephyra acanthitelsonis which had a high fat content (9% wet weight) had a fatty acid composition different from that of another specimen with a normal fat content (3·8%). No significant differences were found between samples of Systellaspis debilis collected from two stations 1000 miles apart.