Analysis of Phenolic Compounds and Antioxidant Activity in Wild Blackberry Fruits

Twenty three different wild blackberry fruit samples were assessed regarding their phenolic profiles and contents (by LC/MS quadrupole time-of-flight (QTOF) and antioxidant activity (ferric reducing ability of plasma (FRAP) and 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS)) by two different extraction methods. Thirty four phenolic compounds were detected (8 anthocyanins, 15 flavonols, 3 hydroxycinnamic acids, 6 ellagic acid derivatives and 2 flavones). In samples, where pressurized liquid extraction (PLE) was used for extraction, a greater increase in yields of phenolic compounds was observed, especially in ellagic acid derivatives (max. 59%), flavonols (max. 44%) and anthocyanins (max. 29%), than after extraction by the ultrasonic technique extraction (UAE) method. The content of phenolic compounds was significantly correlated with the antioxidant activity of the analyzed samples. Principal component analysis (PCA) revealed that the PLE method was more suitable for the quantitative extraction of flavonols, while the UAE method was for hydroxycinnamic acids.     

Multi-device anonymous authentication

Recently, a few pragmatic and privacy protecting systems for authentication in multiple systems have been designed. The most prominent examples include Pseudonymous Signatures for German personal identity cards and Anonymous Attestation. The main properties are that a user can authenticate himself with a single private key (stored on a smart card), but nevertheless the user’s IDs in different systems are unlinkable. We develop a solution which enables a user to achieve the above-mentioned goals while using more than one personal device, each holding a single secret key, but different for each device. Our solution is privacy preserving: it will remain hidden for the service system which device is used. Nevertheless, if a device gets stolen, lost or compromised, the user can revoke it (leaving his other devices intact). In particular, in this way we create a strong authentication framework for cloud users, where the cloud does not learn indirectly personal data. Our solution is based on a novel cryptographic primitive, called Pseudonymous Public Key Group Signature.

     

Method of determination of palladium concentration for C-Pd nanostructural films as a function of film thickness,roughness and topography

In this paper a method of determination of Pd in a carbon-palladium film (C-Pd film) deposited on a quartz substrate is presented. This method is based on energy dispersive X-ray spectroscopy (EDX) and all experiments were performed using a scanning electron microscope (SEM) equipped with EDX system. Qualitative and quantitative analyses were carried out for C-Pd films prepared by PVD method in different technological conditions. It was shown that results of the experiments depended on the structural model, film thickness and electron beam energy used for Pd content calculation. This method enabled us to conclude on the homogeneity of palladium distribution in the whole volume of carbonaceous matrix, depending on the parameters of PVD process. Additionally, these studies showed that a different palladium concentration in C-Pd films had a significant impact on their topography and morphology.     

Hyperequivalence of logic programs with respect to supported models

Recent research in nonmonotonic logic programming has focused on certain types of program equivalence, which we refer to here as hyperequivalence, that are relevant for program optimization and modular programming. So far, most results concern hyperequivalence relative to the stable-model semantics. However, other semantics for logic programs are also of interest, especially the semantics of supported models which, when properly generalized, is closely related to the autoepistemic logic of Moore. In this paper, we consider a family of hyperequivalence relations for programs based on the semantics of supported and supported minimal models. We characterize these relations in model-theoretic terms. We use the characterizations to derive complexity results concerning testing whether two programs are hyperequivalent relative to supported and supported minimal models.     

Influence of Electrostatic Interactions on Complexes with Short O···O Hydrogen Bonds in Basic Salts of Pyridine Betaines and Acid Salts of ω-Phenyloalkanocarboxylic Acids

The isostructural complexes [C₅H₅N⁺(CH₂)_nCOO]₂HX and [C₆H₅(CH₂)_nCOO]₂HK (n = 1–4), which differ in their counterions and charge on the ring, were synthesized, and their powder FT-IR spectra analyzed. All complexes containing a charged pyridine ring are of Hadži type iii, characterized by an intense broad (continuum) absorption below 1600 cm⁻¹ typical of a short-strong hydrogen bond (SSHB) with a delocalized proton and a single vC=O band. The positively charged nitrogen atoms interact electrostatically with the X⁻ ion and, additionally, with one of the oxygen atoms of the carboxylic group, producing a more or less symmetric environment of the H-bonded proton, and stabilizing the SSHB. The broad absorption of [C₆H₅CH₂COO]₂HK is very similar to that of other pyridine complexes. Upon addition of methylene groups the broad absorption moves to higher wavenumbers, the O···O distance is elongated, and the H-bonded proton becomes more localized. In the spectrum of [C₆H₅(CH₂)₄COO]₂HK the vC=O and v_asCOO bands were found at 1704 and 1641 cm⁻¹, respectively, which shows that the H-bonded proton is asymmetrically located. The observed variation of absorption with the number of CH₂ groups reflects changes of contacts between the K⁺ ion and COO⁻ groups.     

Oligomerisation of hydroxymethacrylates via Michael-type addition

Attempts to conduct step-growth addition polymerisation of monomethacrylates of oligoethylene glycols via Michael-type addition of hydroxyl groups to carbon-carbon double bonds are presented. In the presence of several basic, nucleophilic and acidic reagents, disproportionation to corresponding glycols and dimethacrylates has been observed while some of them were found to initiate oligomerisation according to afore-said mechanism. Optimal reaction conditions have been established. The most effective initiators, i.e. potassium tert-butoxide and sodium hydride were selected to obtain the series of oligomers. The products were characterised by ¹H NMR, GPC and ESI-MS to confirm oligo(ether-ester) structure and to estimate molecular weight. The latter appeared to be in order of one thousand.     

Radar-echo tracking by use of invariant moments

A number of techniques to track rainfall patterns by use of radar observations have been developed over the years. We present a method for radar-echo tracking based on Hu invariant moments. The method has been tried on several sequences of test images, and the derived displacement fields were in good agreement with the real motions of the tested objects. For the real data obtained from the conventional meteorological radar in Legionowo the method occasionally failed when changes in the radar echo between observations were too large.