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41.
Dimitris P. Makris George Boskou Nikolaos K. Andrikopoulos Panagiotis Kefalas 《European Food Research and Technology》2008,226(5):1075-1079
The stem extract, which was shown to contain high amounts of phenolics and significant antioxidant potency, was further analysed
employing liquid chromatography-electrospray ionisation mass spectrometry, in an effort to obtain a deeper insight into its
polyphenolic composition. The compounds identified were mainly flavanols (a trimer and a galloylated dimer), flavonols (rutin
and quercetin 3-O-glucuronide), stilbenes (trans-resveratrol and a resveratrol dehydrodimer) and a dihydroflavonol glycoside (astilbin). 相似文献
42.
Ayman El Agha Dimitris P. Makris Panagiotis Kefalas 《European Food Research and Technology》2008,227(5):1379-1386
A very large amount of phenol-polluted waters are formed from the production of olive oil (olive mill waste water, OMWW),
and the main problem associated with their disposal is a viable means of effective treatment. Biochemical processes used for
treating OMWW are generally considered to be of high capital and operating costs with limited efficiency. This is mainly due
to particularly high levels of phenolic compounds, which are considered major contributors to the toxicity and antibacterial
activity of OMWW, and limit their microbial treatment and/or use as fertilizers. Although the use of bacterial and fungal
enzymes has gained interest in studies pertaining to bioremediation applications, plant enzymes have been given less attention
or even disregarded. In this view, this study aimed at investigating the use of a crude peroxidase preparation from onion
solid by-products for oxidising hydrocaffeic acid, a typical o-diphenol with a structure very similar to various phenolic derivatives that may occur in OMWW. Increased enzyme activity
was observed at a pH value of 4, but considerable activity was also retained for pH upto 7. Favourable temperatures for increased
activity varied between 30 and 50 °C, 40 °C being the optimal. Liquid chromatography–mass spectrometry analysis of a homogenate/H2O2-treated hydrocaffeic acid solution revealed the existence of three major oxidation products, which were identified as dehydrodimers.
Based on the data generated, a putative pathway for the formation of the peroxidase-mediated hydrocaffeic dehydrodimers was
proposed. 相似文献
43.
P. S. Krishnaprasad Dimitris P. Tsakiris 《Dynamical Systems: An International Journal》2001,16(4):347-397
This paper is concerned with the problem of motion generation via cyclic variations in selected degrees of freedom (usually referred to as shape variables) in mechanical systems subject to non-holonomic constraints (here the classical system of a disc rolling without sliding on a flat surface). In earlier work, we identified an interesting class of such problems arising in the setting of Lie groups, and investigated these under a hypothesis on constraints, that naturally led to a purely kinematic approach. In the present work, the hypothesis on constraints does not hold, and as a consequence, it is necessary to take into account certain dynamical phenomena. Specifically we concern ourselves with the group SE (2) of rigid motions in the plane and a concrete mechanical realization dubbed the 2-node, 1-module SE (2)snake. In a restricted version, it is also known as the Roller Racer (a patented ride/ toy). Based on the work of Bloch, Krishnaprasad, Marsden and Murray, one recognizes in the example of this paper a balance law called the momentum equation, which is a direct consequence of the interaction of the SE (2)-symmetry of the problem with the constraints. The systematic use of this type of balance law results in certain structures in the example of this paper. We exploit these structures to demonstrate that the single shape freedom in this problem can be cyclically varied to produce a rich variety of motions of the SE (2)-snake. In their study of the snakeboard, a patented modification of the skateboard that also admits the group SE (2) as a symmetry group, Lewis, Ostrowski, Burdick and Murray exploited the same type of balance law as that discussed here to generate motions. A key difference, however, is that, in the present paper, we have only one control variable and thus controllability considerations become somewhat more delicate. In the present paper, we give a self-contained treatment of the geometry, mechanics and motion control of the Roller Racer. 相似文献
44.
A commercial serine‐type protease preparation (Alcalase) was examined as a scouring agent for cotton fabrics. Application of the enzyme induced moderate changes in the composition of fibers that were mainly associated with the removal of protein and waxes. The relationship between the compositional modifications and structural transformations, which were reflected in the crystallinity index of the bioscoured cotton fibers, was demonstrated. The protease‐treated textiles displayed superior whiteness and outstanding compressional resilience but exhibited a poor hydrophilicity and dyeing capacity. One‐step scouring at neutral conditions, where proteolytic activity was supported by multienzyme combinations, could generate textiles with sufficient water absorbency and advanced performance. The implementation of the appropriate scouring conditions (concentration and combination of enzymes) could form fabrics with the desired physicochemical and micromechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
45.
46.
Stamatina Kallithraka Laura Aliaj Dimitris P. Makris Panagiotis Kefalas 《International Journal of Food Science & Technology》2009,44(12):2385-2393
A range of fourty‐six red grape (Vitis vinifera spp.) samples, originating from six widely cultivated varieties and covering major parts of the Hellenic vineyard, were assayed for their content in six principal anthocyanin pigments. Representative in vitro antioxidant parameters were also determined, including antiradical activity (AAR), reducing power (PR) and hydroxyl free radical scavenging activity (SAHFR). Quantitative determination using high performance liquid chromatography showed that the prevalent pigment was malvidin 3‐O‐glucoside (average content 82.53 mg per 100 g fresh berry weight), followed by its coumarate derivative (29.26 mg per 100 g), paeonidin 3‐O‐glucoside (10.84 mg per 100 g), petunidin 3‐O‐glucoside (7.80 mg per 100 g) cyanidin 3‐O‐glucoside (5.67 mg per 100 g) and delphinidin 3‐O‐glucoside (1.28 mg per 100 g). The richest variety was Syrah, with total average anthocyanin content of 186.02 mg per 100 g, whereas the Hellenic native variety Xinomavro had the lowest average anthocyanin level (38.70 mg per 100 g). The establishment of correlations of individual and total anthocyanin contents with the values from the antioxidant test was accomplished with linear regression. The links of total anthocyanins were significant with all antioxidant parameters (P < 0.001), but more importantly with SAHFR (R2 = 0.740). Malvidin 3‐O‐glucoside content had the higher correlation with SAHFR compared with all other anthocyanins (R2 = 0.698, P < 0.001). 相似文献
47.
Elias Kiassos Stefania Mylonaki Dimitris P. Makris Panagiotis Kefalas 《Innovative Food Science and Emerging Technologies》2009,10(2):246-252
An experimental setup based on a 23-full factorial, central composite design was implemented with the aim to optimising recovery of polyphenols from onion solid wastes (OSW). In order to allow for the establishment of a sustainable process, reusable and non-toxic solutions composed of water/ethanol/citric acid were employed as extracting media. The factors considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained produced a satisfactory fitting of the experimental data with regard to total polyphenol extraction (R2 = 0.97, p = 0.0025) and the reducing power of the extracts (R2 = 0.97, p = 0.0033), but not with the antiradical activity (R2 = 0.89, p = 0.0592). The 2nd order polynomial equations obtained after elaboration of the experimental data indicated that all parameters considered were significant in respect with the efficiency of total polyphenol recovery. The highest total polyphenol yield was theoretically predicted to be 9342 ± 1435 mg gallic acid equivalents per 100 g dry weight, under optimal conditions (60% EtOH, pH 2 and 4.2 h). Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were quercetin 3,4′-diglucoside, quercetin 4′-glucoside and quercetin. Simple linear regression analysis between the total polyphenol and the antiradical activity of the OSW extracts showed that there was no correlation in a statistically significant manner, as opposed to reducing power.Industrial relevanceThe recovery of value-added substances from agri-food industrial wastes is an issue with importance pertaining to both the reduction of the waste load released to the environment, and the development of novel, natural food additives with functional properties. Up to date, the examinations pertaining to the clarification of factors that can affect extractability were based on rather unilateral assessment, while it is generally accepted that the retrieval depends on several parameters, which render the phenomenon a particular complexity. In this view, the implementation of factorial design with respect to investigating in parallel several factors pertaining to efficient polyphenol recovery becomes imminent. Thus the establishment of models on such a sound experimental basis is expected to provide a reliable background for more costand resource-effective processes, with a potential direct industrial applicability. 相似文献
48.
Performance analysis of IEEE 802.11 ad hoc networks in the presence of exposed terminals 总被引:1,自引:0,他引:1
The paper evaluates the performance effects of exposed terminals in IEEE 802.11 ad hoc networks in finite load conditions. It derives analytical models for the estimation of channel utilization and media access delay for IEEE 802.11 ad hoc networks in finite load conditions with and without exposed terminals. The simulation results show that the analytical estimated channel utilization and media access delay metrics are fairly accurate. 相似文献
49.
Anna Campanati Emanuela Martina Federico Diotallevi Giulia Radi Andrea Marani Davide Sartini Monica Emanuelli George Kontochristopoulos Dimitris Rigopoulos Stamatis Gregoriou Annamaria Offidani 《International journal of molecular sciences》2021,22(13)
Saliva is easy to access, non-invasive and a useful source of information useful for the diagnosis of serval inflammatory and immune-mediated diseases. Following the advent of genomic technologies and -omic research, studies based on saliva testing have rapidly increased and human salivary proteome has been partially characterized. As a proteomic protocol to analyze the whole saliva proteome is not currently available, the most common aim of the proteomic analysis is to discriminate between physiological and pathological conditions. The salivary proteome has been initially investigated in several diseases: oral squamous cell carcinoma and oral leukoplakia, chronic graft-versus-host disease, and Sjögren’s syndrome. Otherwise, salivary proteomics studies in the dermatological field are still in the initial phase, thus the aim of this review is to collect the best research evidence on the role of saliva proteomics analysis in immune-mediated skin diseases to understand the direction of research in this field. The results of PRISMA analysis reported herein suggest that human saliva analysis could provide significant data for the diagnosis and prognosis of several immune-mediated and inflammatory skin diseases in the next future. 相似文献
50.
Gabriel Tsechpenakis Dimitris Metaxas Carol Neidle 《Computer Vision and Image Understanding》2006,104(2-3):140
We present a data-driven dynamic coupling between discrete and continuous methods for tracking objects of high dofs, which overcomes the limitations of previous techniques. In our approach, two trackers work in parallel, and the coupling between them is based on the tracking error. We use a model-based continuous method to achieve accurate results and, in cases of failure, we re-initialize the model using our discrete tracker. This method maintains the accuracy of a more tightly coupled system, while increasing its efficiency. At any given frame, our discrete tracker uses the current and several previous frames to search into a database for the best matching solution. For improved robustness, object configuration sequences, rather than single configurations, are stored in the database. We apply our framework to the problem of 3D hand tracking from image sequences and the discrimination between fingerspelling and continuous signs in American Sign Language. 相似文献