Studying ancient crop provenance: implications from δ(13)C and δ(15)N values of charred barley in a Middle Bronze Age silo at Ebla(NW Syria)

The discovery of a storeroom full of barley and other cereals (L.9512) in the proto-historic site of Ebla has provided a unique opportunity to study the centralized storage system of the early city-state from a different perspective. Epigraphic evidence available within the site reveals a complex system of taxation which included gathering grain tributes from satellite sites and redistributing semi-finished products such as flour. In this paper, we intend to explore the possibilities of a combined approach to studying the storage system, based on estimated barley grain volumes and δ(13)C-δ(15)N analyses. This approach is used to distinguish between grain from different harvesting sites and to identify any grain cultivated using special agricultural practices (e.g. manuring or irrigation). The basic assumption for this kind of analysis is that the growth-site conditions, natural or anthropogenic, of harvested cereals are reflected in their grain size and δ(13)C-δ(15)N values. Since the remains found in the storeroom were charred, the first task was to evaluate the effect of carbonization on the δ(13)C-δ(15)N and the size of the grains. Thus, the effect of charring was tested on modern samples of Syrian barley landraces. Once it had been ascertained that fresh grains reduced to charred remains retain their original biometric and isotopic traits, the ancient material was examined. Thirteen groups were identified, each characterized by a specific average volume and specific carbon and nitrogen values. The analysis revealed that what had first appeared to be a homogeneous concentration of grain was in fact an assemblage of barley harvested from different sites.     

A self-assembled, metallo-organic supramolecular frequency doubler

The dimeric self-assembly program of a new, multidentate ligand with cuprous ions overcomes crystal packing forces, which leads to C(i) symmetry in the solid state, to form a no less than partially C(2)-symmetric structure in solution. The resulting tetranitro-substituted dicopper(i) metallocyclophane displays an exceptionally strong second harmonic frequency response (β = (3000 ± 600) × 10(-30) esu for a fundamental at 800 nm).     

Sulla funzione di Hilbert di un sottoschema zero-dimensionale diP 3

Riassunto In questo lavoro diamo una caratterizzazione aritmetica della differenza prima ΔH(X,−) della funzione di Hilbert di un sottoschema chiuso 0-dimensionaleX diP ³. Il risultato principale viene applicato per dimostrare che seX è contenuto in una completa intersezione di tipo(a, b, c), a≦b≦c allora ΔH(X, n) è decrescente pern≧a+c−2.

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Summary In this paper we give an aritmetical characterization of the first difference ΔH(X,−) of the Hilbert function of a closed 0-dimensional subschemeX ofP ³. The main result is then applied to prove that ifX is contained in a complete intersection of type(a, b, c), a≦b≦c then ΔH(X, n) is decreasing forn≧a+c−2.

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Lavoro svolto con finanziamento MPI.     

Vibrational spectrum and assignment of 4-cyclopentene-1,3-dione

The IR and Raman spectra of 4-cyclopentene-1,3-dione have been studied. A complete assignment of the observed bands is proposed on the basis of the usual criteria (contours of the IR bands in the vapour phase and depolarization state of the Raman bands). For the planar species the assignment is confirmed by a normal-coordinate calculation.     

Enantioselective hydrogen transfer reactions from propan-2-ol to ketones catalyzed by pentacoordinate iridium(I) complexes with chiral Schiff bases

Some diastereoisomeric pentacoordinate complexes of the type [Ir(COD)-(NNR)I] (COD = cis,cis-1,5-cyclooctadiene; NNR = 2-pyridinal-1-phenylethylimine (PPEI) (I), 2-acetylpyridine-1-phenylethylimine (APPEI) (II)) have been synthesized. The complexes are active and selective catalysts for asymmetric hydrogen transfer from propan-2-ol to prochiral ketones. Optical yields of up to 84% have been obtained in the reduction of t-butyl phenyl ketone. The structure and absolute configuration of complexes I and II were determined by X-ray diffraction.     

Determination of boron in silicon-doped gallium arsenide by electrothermal atomic absorption spectrometry and ultraviolet-visible spectrophotometry

Two methods have been developed for the determination of boron impurities in silicon-doped gallium arsenide (GaAs) for electronics. The first method employs the electrothermal atomic absorption spectrometry (ETAAS), the second, the UV-Vis molecular absorption spectrophotomety. In both cases the GaAs sample is decomposed with aqua regia (1+1). To prevent Ga(III) interference on the ETAAS determination of boron, a double extraction of the chlorogallic acid (HGaCl4) in diethyl ether is performed. To improve the overall ETAAS performance, the graphite tubes were pre-treated with iridium(III) and tungsten(IV). A mixed chemical modifier containing Ni(II), Sr(II) and citric acid was also used. The characteristic mass (m0) is 301 +/- 47 pg and the detection limit (3sB) is 2.4 microg g(-1). The classic UV-Vis spectrophotometric procedure using curcumin was also extended to the determination of boron in GaAs. By masking Ga(III) with EDTA and a preliminary extraction of boron with 2-ethyl-hexane 1,3-diol, performed on a semi-micro scale, a detection limit of 0.6 microg g(-1) was achieved. Both methods were applied to the analysis of two Si-doped GaAs samples which were suspected of being boron-contaminated. Results are compared with those obtained by direct analysis of the decomposed sample solution using the inductively coupled plasma atomic emission spectrometry (ICP-AES).     

Synthesis of polymeric nanocapsules by radical UV‐activated interface‐emulsion polymerization

A new methodology is reported that allows a better control of the synthesis of polymeric core–shell nanocapsules. These nanocapsules were made of biocompatible polymers, obtained from poly(ethylene glycol)diacrylate and poly(ethylene glycol) methyl ether methacrylate, and were used as carrier for curcumin as therapeutic agent. The impact of manufacturing factors (time of sonication, time of UV irradiation, and type of monomer) was investigated in relation to the average size of nanocapsules, their distribution, shape, composition, stability, and their capability to deliver curcumin. We successfully synthesized core–shell nanocapsules in various sizes, ranging from 80 nm to 300 nm, by acting either on the process conditions or on the composition of the monomer mixture. This wide range of sizes makes the method here proposed very promising for the production of nanocarriers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3357–3369     

Study of Ground State Interactions of Enantiopure Chiral Quaternary Ammonium Salts and Amides,Nitroalkanes, Nitroalkenes,Esters, Heterocycles,Ketones and Fluoroamides

Chiral phase-transfer catalysis provides high level of enantiocontrol, however no experimental data showed the interaction of catalysts and substrates. ¹H NMR titration was carried out on Cinchona and Maruoka ammonium bromides vs. nitro, carbonyl, heterocycles, and N−F containing compounds. It was found that neutral organic species and quaternary ammonium salts interacted via an ensemble of catalyst ⁺N−C−H and (sp²)C−H, specific for each substrate studied. The correspondent BArF salts interacted with carbonyls via a diverse set of ⁺N−C−H and (sp²)C−H compared to bromides. This data suggests that BArF ammonium salts may display a different enantioselectivity profile. Although not providing quantitative data for the affinity constants, the data reported proofs that chiral ammonium salts coordinate with substrates, prior to transition state, through specific C−H positions in their structures, providing a new rational to rationalize the origin of enantioselectivity in their catalyses.     

Synthesis of 1,4-dihydro-2-methyl-4-oxo-nicotinic acid: Ochiai's route failed

The synthesis of 1,4-dihydro-2-methyl- and 1,4-dihydro-1,2-dimethyl-4-oxo-nicotinic acids was accomplished following a route other than Ochiai's procedure, which yielded the isomer 1,6-dihydro-2-methyl-6-oxo-nicotinic acid ethyl ester, and not the 4-oxo-derivative, as reported. Analytical data confirmed the identity of the two isomer oxo-nicotinic acids. UV-vis and potentiometric preliminary data showed that Al(III) does not form complexes with 1,6-dihydro-2-methyl-6-oxo-nicotinic acid ethyl ester in solution, as expected, but with 1,4-dihydro-2-methyl-4-oxo-nicotinic acid.