On toric locally conformally Kähler manifolds

We study compact toric strict locally conformally Kähler manifolds. We show that the Kodaira dimension of the underlying complex manifold is \(-\infty \), and that the only compact complex surfaces admitting toric strict locally conformally Kähler metrics are the diagonal Hopf surfaces. We also show that every toric Vaisman manifold has lcK rank 1 and is isomorphic to the mapping torus of an automorphism of a toric compact Sasakian manifold.     

Rapid,non-destructive determination of butter adulteration by means of photopyroelectric (PPE) calorimetry

The study focuses on the application of the photopyroelectric (PPE) technique combined with gas chromatography to detect adulteration of cow milk-obtained butter. The thermal diffusivity and effusivity have been directly measured using back and front PPE detection, respectively, and the results have been correlated with the composition of adulterated butter samples. The back detection configuration has been used in the case of butter adulterated with palm oil, and a possible correlation of the thermal diffusivity with total amount of monounsaturated fatty acids composition has been proposed. For butter adulterated with soy milk, we used the front PPE configuration in order to measure the samples’ thermal effusivity. A strong dependence of the value of thermal effusivity as a function of soy milk content was found.     

Identification and Affinity-Quantification of ß-Amyloid and α-Synuclein Polypeptides Using On-Line SAW-Biosensor-Mass Spectrometry

Bioaffinity analysis using a variety of biosensors has become an established tool for detection and quantification of biomolecular interactions. Biosensors, however, are generally limited by the lack of chemical structure information of affinity-bound ligands. On-line bioaffinity-mass spectrometry using a surface-acoustic wave biosensor (SAW-MS) is a new combination providing the simultaneous affinity detection, quantification, and mass spectrometric structural characterization of ligands. We describe here an on-line SAW-MS combination for direct identification and affinity determination, using a new interface for MS of the affinity-isolated ligand eluate. Key element of the SAW-MS combination is a microfluidic interface that integrates affinity-isolation on a gold chip, in-situ sample concentration, and desalting with a microcolumn for MS of the ligand eluate from the biosensor. Suitable MS- acquisition software has been developed that provides coupling of the SAW-MS interface to a Bruker Daltonics ion trap-MS, FTICR-MS, and Waters Synapt-QTOF- MS systems. Applications are presented for mass spectrometric identifications and affinity (K_D) determinations of the neurodegenerative polypeptides, ß-amyloid (Aß), and pathophysiological and physiological synucleins (α- and ß-synucleins), two key polypeptide systems for Alzheimer’s disease and Parkinson’s disease, respectively. Moreover, first in vivo applications of αSyn polypeptides from brain homogenate show the feasibility of on-line affinity-MS to the direct analysis of biological material. These results demonstrate on-line SAW-bioaffinity-MS as a powerful tool for structural and quantitative analysis of biopolymer interactions.

Synthesis,physico-chemical characterization and thermal behavior of new complexes with N4O2 donor set

Three new coordinative compounds of the type [Co(en)₂CO₃]·0.75H₂O (1) and [M(en)₂(H₂O)₂]CO₃ ((2) M:Ni, (3) M:Cu; en: ethylenediamine) were synthesized and characterized. The IR and UV–Vis spectral data indicate that ethylenediamine acts as chelate, while carbonate ions act as bidentate chelate ligand for (1)/counter ion for (2) and (3) generating complexes with octahedral stereochemistry. The thermal behavior provided confirmation of the complexes composition, as well as the number and the nature of water molecules and the intervals of thermal stability. The biological assays revealed a good activity against Enterococcus faecium for copper complex.     

Polymer conjugates with potential biological activity based on new derivatives of 2-mercaptobenzoxazole-synthesis and characterization

New potentially biologically active compounds derived from 2-mercapto-benzoxazole were synthesized and coupled on polymeric support of poly (maleic anhydride-alt-vinyl acetate) for the preparation of polymer-drug conjugates with controlled drug release. All compounds were characterized by elemental and spectroscopy (FT-IR, ¹H-NMR) analysis. The toxicological tests recommend the products for further laboratory screening.      

HPLC/MS analysis of polyphenols,antioxidant and antimicrobial activities of Artabotrys hildebrandtii O. Hffm. extracts

The purpose of this work was to evaluate chemical constituents, antioxidant and antimicrobial activities of Artabotrys hildebrandtii, an endemic medicinal plant from Madagascar. Ethanol extracts from the leaves and stem bark were tested to evaluate DPPH free radical scavenging, using butylated hydroxytoluene and quercetin as standard antioxidants. An high-performance liquid chromatography/mass spectrometry method was developed to investigate the presence of phenolic compounds in the studied samples; gentisic acid, chlorogenic acid, hyperoside, isoquercitrin, rutin, quercitrin, quercetol, apigenin and luteolin were identified. Total polyphenolic content was determined by a spectrophotometric method using Folin–Ciocâlteu reagent. Results showed the efficiency of A. hildebrandtii leaves extract against strains of Staphylococcus aureus and Listeria monocytogenes, as the inhibitory activity is more powerful compared to Gentamicin, used as the standard drug. The leaves of A. hildebrandtii can be considered an important source of polyphenols, especially of rutin, with good antioxidant and antimicrobial activities.     

Halogen bonds on demand: I...S contacts in cocrystals of trans‐bis(thiocyanato‐κN)tetrakis(4‐vinylpyridine‐κN)nickel(II) and 2,3,5,6‐tetrafluoro‐1,4‐diiodobenzene

Hydrogen bonds are considered a powerful organizing force in designing supramolecular architectures because they are directional, selective and reversible at room temperature. trans‐Dithiocyanatotetrakis(4‐vinylpyridine)nickel(II) is a popular host for the inclusion of small molecules and 2,3,5,6‐tetrafluoro‐1,4‐diiodobenzene (TFDIB) represents a strong halogen‐bond donor. These constituents cocrystallize in a 1:1 stoichiometry, [Ni(NCS)₂(C₇H₇N)₄]·C₆F₄I₂, in the tetragonal space group I4₁/a. Both residues occupy special positions, i.e. the pseudo‐octahedral Ni^II complex is located on a twofold axis and the TFDIB molecule sits about a crystallographic centre of inversion. The components interact via a short S...I contact of 3.2891 (12) Å between the thiocyanate S atom of the host and the iodine substituent at the perhalogenated aromatic ring of the smaller guest molecule. This interaction meets the commonly accepted criteria for a halogen bond. Such halogen bonds to sulfur are significantly less common than to smaller electronegative atoms.     

Anthocyanins profile,total phenolics and antioxidant activity of two Romanian red grape varieties: Fetească neagră and Băbească neagră (<Emphasis Type="Italic">Vitis vinifera</Emphasis>)

The phenolic composition of Feteasc? neagr?and B?beasc? neagr? grapes from Dealul Bujorului vineyard (south-east Romania) was studied using the spectrophotometric and high-performance liquid chromatographic (HPLC) methods. The results revealed significant differences between these cultivars. Total anthocyanins ranged from 0.22–5.98 mg g^?1 DW berries in B?beasc? neagr? grapes to 0.54–18.54 mg g^?1 DW berries in Feteasc? neagr?. Both cultivars were characterised by an interesting anthocyanin profile for winemaking with a prevalence of malvidin-3-glucoside. The skins and seeds both had small amounts of flavonoids. In contrast with B?beasc? neagr?, Feteasc? neagr? had more flavonoids in the seeds (69 %) than in the skins. Statistically significant correlations were observed between antioxidant activity and total anthocyanin content in both varieties. The antioxidant activity was also found to be highly correlated to the total phenolic compounds content.     

Stirling Refrigerating Machine Modeling Using Schmidt and Finite Physical Dimensions Thermodynamic Models: A Comparison with Experiments

The purpose of the study is to show that two simple models that take into account only the irreversibility due to temperature difference in the heat exchangers and imperfect regeneration are able to indicate refrigerating machine behavior. In the present paper, the finite physical dimensions thermodynamics (FPDT) method and 0-D modeling using the Schmidt model with imperfect regeneration were applied in the study of a β type Stirling refrigeration machine.The 0-D modeling is improved by including the irreversibility caused by imperfect regeneration and the finite temperature difference between the gas and the heat exchangers wall. A flowchart of the Stirling refrigerator exergy balance is presented to show the internal and external irreversibilities. It is found that the irreversibility at the regenerator level is more important than that at the heat exchangers level. The energies exchanged by the working gas are expressed according to the practical parameters, necessary for the engineer during the entire project. The results of the two thermodynamic models are presented in comparison with the experimental results, which leads to validation of the proposed FPDT model for the functional and constructive parameters of the studied refrigerating machine.