Measurement of K-line transition rates for Ti, V, Cr, Mn, Fe and Co using synchrotron radiation

Transition rates were obtained from spectra for pure metallic samples of atomic number ranging from 22 to 27, measured with monochromatic incident X-ray beams from a synchrotron source. The experimental setup for this consisted of an energy dispersive spectrometer in a conventional 45–45° geometry, mounted in an evacuated chamber. Absorption, detector efficiency and multiple scattering were taken into account. The results obtained are compared with recent theoretical and experimental data as well as with the well-known theoretical predictions from Scofield.     

Nanospheres,Nanotubes, Toroids,and Gels with Controlled Macroscopic Chirality

The interaction of a highly dynamic poly(aryl acetylene) (poly‐ 1 ) with Li⁺, Na⁺_, and Ag⁺ leads to macroscopically chiral supramolecular nanospheres, nanotubes, toroids, and gels. With Ag⁺, nanospheres with M helicity and tunable sizes are generated, which complement those obtained from the same polymer with divalent cations. With Li⁺ or Na⁺, poly‐ 1 yields chiral nanotubes, gels, or toroids with encapsulating properties and M helicity. Right‐handed supramolecular structures can be obtained by using the enantiomeric polymer. The interaction of poly‐ 1 with Na⁺ produces nanostructures whose helicity is highly dependent on the solvation state of the cation. Therefore, structures with either of the two helicities can be prepared from the same polymer by manipulation of the cosolvent. Such chiral nanotubes, toroids, and gels have previously not been obtained from helical polymer–metal complexes. Chiral nanospheres made of poly(aryl acetylene) that were previously assembled with metal(II) species can now be obtained with metal(I) species.     

Nanospheres,Nanotubes, Toroids,and Gels with Controlled Macroscopic Chirality

The interaction of a highly dynamic poly(aryl acetylene) (poly‐ 1 ) with Li⁺, Na⁺_, and Ag⁺ leads to macroscopically chiral supramolecular nanospheres, nanotubes, toroids, and gels. With Ag⁺, nanospheres with M helicity and tunable sizes are generated, which complement those obtained from the same polymer with divalent cations. With Li⁺ or Na⁺, poly‐ 1 yields chiral nanotubes, gels, or toroids with encapsulating properties and M helicity. Right‐handed supramolecular structures can be obtained by using the enantiomeric polymer. The interaction of poly‐ 1 with Na⁺ produces nanostructures whose helicity is highly dependent on the solvation state of the cation. Therefore, structures with either of the two helicities can be prepared from the same polymer by manipulation of the cosolvent. Such chiral nanotubes, toroids, and gels have previously not been obtained from helical polymer–metal complexes. Chiral nanospheres made of poly(aryl acetylene) that were previously assembled with metal(II) species can now be obtained with metal(I) species.     

Physicochemical Properties,Fatty Acid Composition,Volatile Compounds of Blueberries,Cranberries, Raspberries,and Cuckooflower Seeds Obtained Using Sonication Method

Every year, thousands of tons of fruit seeds are discarded as agro-industrial by-products around the world. Fruit seeds are an excellent source of oils, monounsaturated fatty acids, and n-6 and n-3 polyunsaturated essential fatty acids. This study aimed to develop a novel technology for extracting active substances from selected seeds that were obtained after pressing fruit juices. The proposed technology involved sonification with the use of ethyl alcohol at a low extraction temperature. Seeds of four species—blueberry (Vaccinium myrtillus L.), raspberry (Rubus idaeus), cranberry (Vaccinium macrocarpon), and cuckooflower (Cardamine pratensis)—were used for extraction. Following alcohol evaporation under nitrogen, the antioxidant activity, chemical composition, and volatile compounds of the obtained extracts were analyzed using chromatographic methods, including gas chromatography (GC)–mass spectrometry (MS) (GC–MS/MS), and high-performance liquid chromatography–MS. We analyzed physicochemical properties, fatty acid, and volatile compounds composition, sterol and tocochromanol content of blueberry, cranberry, raspberry, and cuckooflower seed oils obtained by sonication. This method is safe and effective, and allows for obtaining valuable oils from the seeds.     

Synthesis and study of the properties of tetrazoles,azides, triazenes,and azo compounds of the thiadiazole series

Azo compounds and bistriazenes were obtained by diazo coupling of diazotized 5-amino-2-R-1,3,4-thiadiazoles; tetrazolo[4,5-b]-1,3,4-thiadiazoles, to which azido-tetrazole tautomerism is peculiar, were obtained by replacement of the diazo group by an azido group. The structures of the products were confirmed by their IR and UV spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 933–936, July, 1980.     

Heterogeneous-catalytic fischer reaction. 13. Catalytic synthesis of 4-, 5-, 6-, and 7-methoxyindoles

Methoxy-substituted acetaldehyde phenylhydrazones were cyclized in the vapor phase on a GIPKh-115 catalyst to give 4-, 5-, 6-, and 7-methoxyindoles. 5-Methoxyindole was obtained in 50% yield, 4- and 6-methoxyindoles were obtained in 85% yield, and 7-methoxyindole was obtained in 45% yield.See [1] for Communication 12.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1054–1055, August, 1982.     

Effect of Acid, Steam Explosion, and Size Reduction Pretreatments on Bio-oil Production from Sweetgum, Switchgrass, and Corn Stover

Bio-oil produced from biomass by fast pyrolysis has the potential to be a valuable substitute for fossil fuels. In a recent work on pinewood, we found that pretreatment alters the structure and chemical composition of biomass, which influence fast pyrolysis. In this study, we evaluated dilute acid, steam explosion, and size reduction pretreatments on sweetgum, switchgrass, and corn stover feedstocks. Bio-oils were produced from untreated and pretreated feedstocks in an auger reactor at 450?°C. The bio-oil??s physical properties of pH, water content, acid value, density, and viscosity were measured. The chemical characteristics of the bio-oils were determined by gas chromatography?Cmass spectrometry. The results showed that bio-oil yield and composition were influenced by the pretreatment method and feedstock type. Bio-oil yields of 52, 33, and 35?wt% were obtained from medium-sized (0.68?C1.532?mm) untreated sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from other sizes. Bio-oil yields of 56, 46, and 51?wt% were obtained from 1?% H₂SO₄-treated medium-sized sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from untreated and steam explosion treatments.     

A sequential multielement separation scheme for determination of As,Mn, Mo,Cu and Zn in human milk by neutron activation analysis

A simple separation scheme for the analysis of As, Mn, Mo, Cu and Zn using neutron activation is described. It has been checked using three standard reference materials, A-11 milk powder (IAEA) and bovine liver and orchard leaves (USNBS) and found to give acceptable results. This scheme was applied for determination of these trace elements in mature human milk samples. The concentrations of As, Mn, Mo, Cu in samples obtained from two socio-economic groups—low and middle incomes—were not significantly different. However, Zn levels in samples obtained from the poor income group were significantly lower than in those obtained from the other group. Work carried out under Research Contract No. 2598/RB of International Atomic Energy, Vienna. Health Physics Division. Analytical Chemistry Division.     

Mass spectrometric separation and quantitation of overlapping isotopologues. Deuterium containing hydrides of As,Sb, Bi,Sn, and Ge

Mass spectra of fully and partially deuterated As, Sb, Bi, Ge, and Sn hydrides have been obtained using several mathematical approaches aimed at signal extraction and reconstruction. Study of such hydride mixtures is important for the elucidation of hydride generation mechanisms. In this approach, mass spectra of partially deuterated isotopomers, i.e., AsH₂D and AsHD₂, are extracted using the weighted two-band target entropy minimization method. Alternatively, these mass spectra were constructed from the mass spectra of fully deuterated and hydrogenated hydrides using the statistical approach in fragmentation pathways. Concentration profiles of all deuterated hydrides were obtained from their overlapping mixture mass spectra using least-squares deconvolution.     

Determination of total, organic solvent extractable, volatile and tetraalkyllead in fish, vegetation, sediment and water samples

Procedures for the determination of total, hexane extractable, volatile and tetraalkyllead in fish, vegetation, sediment and water samples are given. Detection limits, better than those obtainable by any other published methods, are in the range of 10–50 ppb-total Pb, 2-ppb-hexane extractable Pb, 0.5–1.5 ppb-volatile Pb and 0.5 ppb-tetraalkyllead. Standard reference samples from National Bureau of Standards were used as controls where applicable and satisfactory agreement was obtained between accepted values and values obtained by the proposed procedure.     

Aromatic polyethers,polysulfones, and polyketones as laminating resins. II

1,3-Bis(p-phenoxybenzenesulfonyl)benzene and 4,4′-bis(p-phenoxybenzenesulfonyl)-diphenyl ether were polymerized with isophthaloyl and terephthaloyl chloride in Friedel-Crafts type polymerizations. These polymers had 5-cyanoisophthaloyl units in the backbone, obtained by using 5-cyanoisophthaloyl chloride as part of the acid chloride monomer. A number of catalysts were screened to effect the trimerization of the pendant nitrile groups in the polymer to the triazines. Model reactions were carried out for each polymer. Physical and thermal properties of the laminates obtained from these polymers are discussed.     

The aminomethylation of adenine,cytosine and guanine

Aminomethylated derivatives of adenine, cytosine and guanine have been isolated and characterized for the first time. These results are important because of the potential for similar adducts being formed transiently between nucleosides and nucleotides, and endogenous aldehydes and amines in vivo, and of the potential use of similar adducts for drug delivery. Mono-alkylated products obtained were from the reaction of adenine with one equivalent of aminomethylating agent derived from amines exhibiting lower basicity (e.g., morpholine and N-methylpiperazine); bis-alkylated products were obtained with agents derived from more basic amines regardless of the stoichiometry. On the other hand, only bis-alkylated products were obtained from the reaction of cytosine or guanine with the aminomethylating agent regardless of the basicity of the secondary amine used or the stoichiometry of the reaction. The mono-alkylated adenine products were alkylated on N-9 while the bis-alkylated cytosine products were alkylated on N-9 and N⁴ and the bis-alkylated adenine products were alkylated on N-9 and N⁶. The adenine and cytosine aminomethyl adducts hydrolyzed rapidly in dilute aqueous solution.     

Steroid glycosides of the seeds ofSolanum melongena. Structures of melongosides A,B, E,F, and H

Three chromatographically individual fractions, each containing tigogenin glycosides and diosgenin glycosides have been isolated by chromatography on a silica gel column from a methanolic extract of eggplant seeds. To separate the mixture of two difficultly separable glycosides into individual components, each fraction was acetylated and epoxidated, and the derivatives obtained were separated chromatographically. The tigogenin glycoside peracetates isolated were saponified, and the diosgenin epoxide glycoside acetates were de-epoxidated and saponified, to give the individual glycosides, melongosides A, B, E, F, and H. The complete chemical structure of each melongoside has been shown with the aid of acid hydrolysis, methylation, and periodate oxidation followed by a study of the products obtained.Division of Plant Genetics, Academy of Sciences of the Moldavian SSR, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 610–614, September–October, 1984.     

Solvent Extraction Studies of Two Isomeric 5, 7, 7, 12, 12, 14-Hexamethy-1, 4, 8, 11-Tetraazacyclotetradecanes

The distribution ratios of two isomeric 5, 7, 7, 12, 12, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecane, tet c and tet d, in several solvent systems at 25.0°C as functions of hydrogen ion concentration were determined. The protonation constants and the distribution constants of these macrocyclic ligands and their protonated species were obtained from the variations of the distribution ratios in the range of 6<–log [H⁺]<14.     

An improved synthesis of 3-deazaeytosine, 3-deazauracil, 3-deazacytidine,and 3-deazauridine

3-Dcazacytosine (4-amino-2-pyridone, 3 ), 3-doazauracil (4-hydroxy-2-pyridone, 5 ), 3-deaza-cytidine (4-amino-1-β-D-ribofuranosyl-2-pyridonc, 9 ), and 3-deazauridine (4-hydroxy-1-β-D-ribo-furanosyl-2-pyridone, 11 ) were prepared in high overall yields from 1-methoxy-1-buten-3-yne ( 1 ). Ethyl 3,5,5-triethoxy-3-pentenoate ( 2 ), obtained from acylatioti of 1 with diethyl carbonate and subsequent in situ conjugate addition of ethoxide, was cyelized with ammonia to provide 3 . Diazotization of 3 and subsequent in situ hydroxydediazotization afforded 5 . Nucleoside 9 was obtained from the stannic chloride-catalyzed condensation of bis-trimethylsilylated 3 and 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose ( 7 ), followed by ammonolysis of the blocking groups. Diazotization of 9 and subsequent in situ hydroxydediazotization afforded nucleosidc 11 .     

A novel neolignan, mansoxetane, and two new sesquiterpenes, mansonones R and S, from Mansonia gagei

Three new compounds, mansoxetane; 4′-(3-hydroxy-1,2-oxetanyl)-2′,2-dihydroxy-4-(2-formyl-1-ethyl)-6′,6-dimethoxy biphenyl, and mansonones R and S, together with two previously reported coumarins, mansorins A and C, and four known mansonones, mansonones C, E, G and H, were obtained from the methanolic extract of the heartwood from Mansonia gagei Drumm. Their structures were established by spectroscopic methods.     

Measurement of macroscopic and microscopic thermal neutron cross sections of V,Co, Cu,In, Dy and Au using neutron self-absorption properties

In this study, the total thermal neutron macroscopic and microscopic cross sections of V, Co, Cu, In, Dy and Au were measured using neutron self-absorption properties. Pure foils of these elements with various thicknesses were irradiated using a 5 Ci²³⁸Pu–Be source. After the irradiation, the gamma-spectra of their radionuclides were recorded by an HpGe detector. The gamma-photopeak areas of interest were determined by evaluating the gamma-spectra obtained from the foils. They were plotted as a function of foil thickness for each element. Then a non-linear least-squares fitting method was applied to the functions, and the total thermal neutron macroscopic and microscopic cross sections of V, Co, Cu, In, Dy and Au were obtained.     

Quantitative evaluation of antibacterial activities of nanoparticles (ZnO,TiO2, ZnO/TiO2, SnO2, CuO,ZrO2, and AgNO3) incorporated into polyvinyl butyral nanofibers

Novel hybrid polyvinyl butyral nanofibers have been developed for antimicrobial applications. The nanofiber mats were obtained from a needleless rod electrospinning system. The novel inorganic antibacterial agents were incorporated into the nanofibers, and their antibacterial activity was compared. The obtained nanoparticle/nanofiber hybrid mats have a good surface morphology. The results indicated that the CuO, ZnO, ZnO/TiO₂, and AgNO₃ nanoparticle‐incorporated nanofiber layers have excellent antibacterial activity against to Escherichia coli compared with TiO₂, SnO₂, and ZrO₂ ones. Copyright © 2016 John Wiley & Sons, Ltd.     

All-plastic, disposable, low detection limit ion-selective electrodes

A novel concept for all-plastic and all-solid-state ion-selective electrodes (ISEs) is introduced. Planar, flexible ion-selective electrodes, comprising only polymeric materials, with no internal solution, were obtained. The cast conducting polymer layer (obtained from aqueous suspension) was covered with a solvent polymeric based membrane to obtain a planar all-plastic sensor. The conducting polymer layer served both as electrical contact and as ion-to-electron transducer. To illustrate this concept, the conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) ions (PEDOT-PSS, Baytron P) was chosen. Due to interaction, analyte cations-poly(4-styrenesulfonate) anions, an extended linear range of potentiometric responses was obtained, with lowered detection limit.As example, Ca²⁺-selective and K⁺-selective all-plastic electrodes were fabricated and yielded with high selectivity, near Nernstian slopes and fast responses. The detection limits obtained for Ca²⁺- and K⁺-selective sensors were 5 × 10⁻⁹ M CaCl₂ and 4.4 × 10⁻⁷ M KCl, respectively.The possibilities of modifying the conducting polymer-phase composition is highlighted. This method is extremely useful to tune the desired type of responses, and cannot be directly applied for electrochemically deposited conducting polymers.     

Different Lubricating Oil Treatments for the Determination of Cu,Cr, Fe,Ni, Sb,Pb, and Zn by HR-CS FAAS

Abstract

Microwave-assisted acid decomposition, direct dilution in kerosene, and oil-in-water emulsion were evaluated as lubricating oil pretreatment procedures for Cu, Cr, Fe, Ni, Pb, Sb, and Zn determination by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS). For wet digestion, results were compared with those obtained by Flame Atomic Absorption Spectrometry (FAAS). The ultrasound probe used in emulsions sonication contaminated samples with Cr, although better results have been observed for the other six elements in this condition. In general, recovery percentages ranging from 81–106% (Cu), 80–107% (Cr), 85–114% (Fe), 82–116% (Ni), 86–117% (Pb), 85–115% (Sb), and 81–114% (Zn) were obtained. The HR-CS FAAS showed to be faster and more sensitive than FAAS.