Study of C- and O-glycosylflavones in sugarcane extracts using liquid chromatography: exact mass measurement mass spectrometry

The flavonoids present in sugarcane (Saccharum officinarum) extracts were analyzed by liquid chromatography - mass spectrometry (LC-MS), and a study of the fragmentation patterns of selected flavonoids was conducted using orthogonal acceleration time-of-flight electrospray ionization mass spectrometry (ESI-oa-ToF MS). Seven C- and O-glycosylflavones were identified in the extracts, namely, schaftoside, isoschaftoside, luteolin-8-C-(rhamnosylglucoside), vitexin, orientin, tricin-7-O-neohesperidoside and tricin-7-O-glucoside. Of these, five were identified in the absence of direct comparison with their respective standards. The described method also permitted the differentiation of the 6-C and 8-C isomeric flavones, schaftoside and isoschaftoside. The combination of fragmentation data and exact mass measurement showed to be complimentary to the HPLC-UV-MS techniques previously utilized for isomers discrimination in sugarcane studies.Os flavonóides presentes nos extratos de cana-de-açúcar (Saccharum officinarum) foram analisados por cromatografia líquida acoplada à espectrometria de massas (LC-MS), e o estudo da rota de fragmentação dos flavonóides selecionados foi realizado utilizando a espectrometria de massas com aceleração ortogonal por tempo de vôo e ionização eletrospray (ESI-oa-ToF MS). Sete flavonas C- e O-glicosiladas foram identificadas nos extratos: schaftosídeo, isoschaftosídeo, luteolina-8-C-(ramnosilglicosídeo), vitexina, orientina, tricina-7-O-neohesperidosídeo e tricina-7-O-glicosídeo. Destas, cinco foram identificadas sem comparação direta com seus respectivos padrões. O método descrito também permitiu a diferenciação das 6-C e 8-C flavonas isoméricas, schaftosídeo e isoschaftosídeo. A combinação dos dados de fragmentação e a medida de massa exata mostraram ser complementares às técnicas de HPLC-UV-MS previamente utilizadas para discriminação de isômeros nos estudos da cana-de-açúcar.FAPESPCNP

Crytographic applications of bilinear maps

Bilinear maps have become an important new item in the cryptographer’s toolkit. They first came to prominence when they were used by Menezes, Okamoto and Vanstone to help solve the elliptic curve discrete logarithm problem on elliptic curves of small embedding degree. In 1984, Shamir developed the first identity based signature scheme, and posed the construction of an identity based encryption scheme as an open problem [118]. Subsequently identity based identification and identity based key agreement schemes were proposed. However, identity based encryption remained an open problem. In 2000, Sakai, Ohgishi and Kasahara used bilinear maps to implement an efficient identity based non-interactive key agreement and identity based digital signature [111]. In 2001, some 17 years after it was suggested, Boneh and Franklin proposed the first efficient identity based encryption scheme, constructed using bilinear maps [31]. In this thesis we review some of the numerous cryptographic protocols that have been constructed using bilinear maps. We first give a review of public key cryptography. We then review the mathematics behind the two known bilinear maps, the Weil and Tate pairings, including several improvements suggested m [67, 14]. We develop a Java library to implement pairing based cryptography. In Ch 4 we look at some of the cryptographically hard problems that arise from bilinear maps. In Ch 5 we review identity based signature schemes and present the fastest known scheme. In Ch 6 we review some encryption schemes, make some observations that help improve the performance of many identity based cryptosystems, and propose the fastest scheme for public key encryption with keyword search. In Ch 7 we review identity based key agreements and propose the fastest scheme secure in a modified Bellare-Rogaway model [19]. In Ch 8 we review identity based signcryption schemes and present the fastest known scheme

The effect of charge location in ion mobility mass spectrometry for small molecule analytes

In travelling wave IM-MS an electric field is applied across the IMS cell and analyte collisions with the inert gas give rise to a relationship between the drift time and the molecular shape and overall charge. Recent findings show near baseline IMS separation (R>1) where shape and overall charge appear not to explain the IMS separation. Multiple ion mobility peaks are observed for a single m/z including the fluoroquinolone antibiotics norfloxacin and lomefloxacin, the pesticide indoxacarb and a number of steroids

Equivalence Class Formation in Non-Hearing Impaired Children and Hearing Impaired Children

The relationship between verbal behavior and stimulus equivalence was examined using three sets of children differing in chronological age and verbal ability: (1) non-hearing impaired three and four year olds who had verbal skills generally consistent with their chronological ages; (2) partially hearing (severe to profoundly deaf) children who were rated with verbal ages of above 2 years; and (3) partially hearing children (also severely to profoundly deaf) who were rated with verbal ages of below 2 years. All children were taught a series of four conditional discriminations using unfamiliar stimuli. The children were then tested to determine whether classes of equivalent stimuli had formed. Although all the children were able to learn the conditional discriminations equally well and all the verbally-able children (normal and partially hearing) formed equivalence classes, only one of the verbally-impaired children reliably demonstrated stimulus equivalence formation. These results are consistent with the suggestion that stimulus equivalence and human verbal behavior are closely related

A comparison of collision cross section values obtained via travelling wave ion mobility-mass spectrometry and ultra high performance liquid chromatography-ion mobility-mass spectrometry : application to the characterisation of metabolites in rat urine

A comprehensive Collision Cross Section (CCS) library was obtained via Travelling Wave Ion Guide mobility measurements through direct infusion (DI). The library consists of CCS and Mass Spectral (MS) data in negative and positive ElectroSpray Ionisation (ESI) mode for 463 and 479 endogenous metabolites, respectively. For both ionisation modes combined, TWCCSN2 data were obtained for 542 non-redundant metabolites. These data were acquired on two different ion mobility enabled orthogonal acceleration QToF MS systems in two different laboratories, with the majority of the resulting TWCCSN2 values (from detected compounds) found to be within 1% of one another. Validation of these results against two independent, external TWCCSN2 data sources and predicted TWCCSN2 values indicated to be within 1-2% of these other values. The same metabolites were then analysed using a rapid reversed-phase ultra (high) performance liquid chromatographic (U(H)PLC) separation combined with IM and MS (IM-MS) thus providing retention time (tr), m/z and TWCCSN2 values (with the latter compared with the DI-IM-MS data). Analytes for which TWCCSN2 values were obtained by U(H)PLC-IM-MS showed good agreement with the results obtained from DI-IM-MS. The repeatability of the TWCCSN2 values obtained for these metabolites on the different ion mobility QToF systems, using either DI or LC, encouraged the further evaluation of the U(H)PLC-IM-MS approach via the analysis of samples of rat urine, from control and methotrexate-treated animals, in order to assess the potential of the approach for metabolite identification and profiling in metabolic phenotyping studies. Based on the database derived from the standards 63 metabolites were identified in rat urine, using positive ESI, based on the combination of tr, TWCCSN2 and MS data.</p