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1.
Petros Karalis Anastasia Elektra Poutouki Theodora Nikou Maria Halabalaki Charalampos Proestos Effie Tsakalidou Sofia Gougoura George Diamantopoulos Maria Tassi Elissavet Dotsika 《Molecules (Basel, Switzerland)》2020,25(24)
In recent years, isotopic analysis has been proven a valuable tool for the determination of the origin of various materials. In this article, we studied the 18O and 13C isotopic values of 210 olive oil samples that were originated from different regions in Greece in order to verify how these values are affected by the climate regime. We observed that the δ18O isotopic values range from 19.2 ‰ to 25.2 ‰ and the δ13C values range from −32.7 ‰ to −28.3 ‰. These differences between the olive oils’ isotopic values depended on the regional temperature, the meteoric water, and the distance from the sea. Furthermore, we studied the 13C isotopic values of biophenolic extracts, and we observed that they have same capability to differentiate the geographic origin. Finally, we compared the isotopic values of Greek olive oils with samples from Italy, and we concluded that there is a great dependence of oxygen isotopes on the climatic characteristics of the different geographical areas. 相似文献
2.
A parallel (2, n − 2)-system is investigated here where two units start their operation simultaneously and any one of them is replaced instantaneously upon its failure by one of the (n − 2) cold standbys. We assume availability of n non-identical, non-repairable units for replacement or support. The system reliability is evaluated by recursive relations with unit-lifetimes Ti (i = 1, … , n) that have a general joint distribution function F(t). On the basis of the derived expression, simulation techniques have been developed for the evaluation of the system reliability and the mean time to failure, useful when dealing with large systems or correlated unit-lifetimes and less mathematically manageable distributions. Simulation results are presented for various lifetime distributions and comparisons are made with derived analytic results for some special distributions and moderate values of n. 相似文献
3.
An Animal Model for Human Melanoma 总被引:1,自引:0,他引:1
Adele Green Rachel Neale Roger Kelly Ian Smith Effie Ablett Barry Meyers Peter Parsons 《Photochemistry and photobiology》1996,64(3):577-580
Abstract— Experimental animal models that are directly relevant to human melanoma are lacking. We propose the Angora goat as a potentially useful field model with experimental potential and to this end have examined the prevalence and site distribution of all skin cancers in 28 Angora goat herds in Queensland, Australia. The prevalence of benign melanocytic lesions (lentigines) and their experimental induction by sunlight were also investigated. Among 1731 goats over 2 years of age, 139 malignant skin tumors were excised from 95 affected animals. The prevalence of squamous cell carcinoma (SCC) was 3.8% and of melanoma, 2.2%. Main site of occurrence of melanoma (83%) was the dorsal surface of the ear; in contrast SCC occurred mostly (84%) on the perineum. Lentigines were darker and more prevalent on the exposed compared with the unexposed surface of the ear in Angoras, analogous to the higher prevalence of nevi on the exposed compared with the less exposed inner surface of the arm in humans. Lentigines, which were also found on the perineum though lighter in color than on the dorsal ear, were absent in young animals under 3 months but were numerous in 1–3 year olds. Furthermore in an experimental substudy eight goats, having one flank repeatedly shorn and the contralateral flank left unshorn, revealed consistently more solar lentigines on the shorn flank ( P < 0.05) when both sides were examined after 9 months. Histopathological examination of paired skin biopsies from five of these goats also showed more abundant pigmentation in skin from the exposed, as compared with the unexposed flank. These findings indicate that sunlight induces tumors and lentigines in goats in a highly site-specific manner. The Angora goat model may suggest paradigms for explaining the site differences observed for human melanoma and may also be useful in the future clarification of molecular changes following carcinogenic levels of sun exposure. 相似文献
4.
Vassilis G. Papanicolaou Effie G. Papageorgiou Dimitris C. Lepipas 《Methodology and Computing in Applied Probability》2012,14(2):285-297
Consider a stochastic process that lives on n-semiaxes joined at the origin. On each ray it behaves as one dimensional Brownian Motion and at the origin it chooses a ray
uniformly at random (Kirchhoff condition). The principal results are the computation of the exit probabilities and certain
other probabilistic quantities regarding exit and occupation times. 相似文献
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6.
A central problem in distributed computing and telecommunications is the establishment of common knowledge between two computing entities. An immediate use of such common knowledge is in the initiation of a secure communication session between two entities because the two entities may use this common knowledge to produce a secret key for use with some symmetric cipher. The dynamic establishment of shared information (e.g., secret key) between two entities is particularly important in networks with no predetermined structure such as wireless mobile ad hoc networks. In such networks, nodes establish and terminate communication sessions dynamically with other nodes which may have never been encountered before to somehow exchange information which will enable them to subsequently communicate in a secure manner. In this paper we give and theoretically analyze a protocol that enables two entities initially possessing a string each to securely eliminate inconsistent bit positions, obtaining strings with a larger percentage of similarities. Our analysis involves the modeling of the operation of the protocol with a discrete random process amenable to approximation with a continuous differential equation belonging to the class of Abel's differential equations of the first kind, whose solution involves Lambert's W function. 相似文献
7.
George E. Magoulas Pantelis Afroudakis Kalliopi Georgikopoulou Marina Roussaki Chiara Borsari Theano Fotopoulou Nuno Santarem Emile Barrias Paloma Tejera Nevado Julia Hachenberg Eugenia Bifeld Bernhard Ellinger Maria Kuzikov Irini Fragiadaki Effie Scoulica Joachim Clos Sheraz Gul Maria Paola Costi Wanderley de Souza Kyriakos C. Prousis Anabela Cordeiro da Silva Theodora Calogeropoulou 《Molecules (Basel, Switzerland)》2021,26(14)
A library of seventeen novel ether phospholipid analogues, containing 5-membered heterocyclic rings (1,2,3-triazolyl, isoxazolyl, 1,3,4-oxadiazolyl and 1,2,4-oxadiazolyl) in the lipid portion were designed and synthesized aiming to identify optimised miltefosine analogues. The compounds were evaluated for their in vitro antiparasitic activity against Leishmania infantum and Leishmania donovani intracellular amastigotes, against Trypanosoma brucei brucei and against different developmental stages of Trypanosoma cruzi. The nature of the substituents of the heterocyclic ring (tail) and the oligomethylene spacer between the head group and the heterocyclic ring was found to affect the activity and toxicity of these compounds leading to a significantly improved understanding of their structure–activity relationships. The early ADMET profile of the new derivatives did not reveal major liabilities for the potent compounds. The 1,2,3-triazole derivative 27 substituted by a decyl tail, an undecyl spacer and a choline head group exhibited broad spectrum antiparasitic activity. It possessed low micromolar activity against the intracellular amastigotes of two L. infantum strains and T. cruzi Y strain epimastigotes, intracellular amastigotes and trypomastigotes, while its cytotoxicity concentration (CC50) against THP-1 macrophages ranged between 50 and 100 μM. Altogether, our work paves the way for the development of improved ether phospholipid derivatives to control neglected tropical diseases. 相似文献
8.
Here we examine an active redundant system with scheduled starting times of the units. We assume availability of n non-identical, non-repairable units for replacement or support. The original unit starts its operation at time s1 = 0 and each one of the (n − 1) standbys starts its operation at scheduled time si (i = 2, …, n) and works in parallel with those already introduced and not failed before si. The system is up at times si (i = 2, …, n), if and only if, there is at least one unit in operation. Thus, the system has the possibility to work with up to n units, in parallel structure. Unit-lifetimes Ti (i = 1, …, n) are independent with cdf Fi, respectively. The system has to operate without inspection for a fixed period of time c and it stops functioning when all available units fail before c. The probability that the system is functioning for the required period of time c depends on the distribution of the unit-lifetimes and on the scheduling of the starting times si. The reliability of the system is evaluated via a recursive relation as a function of the starting times si (i = 2, …, n). Maximizing with respect to the starting times we get the optimal ones. Analytical results are presented for some special distributions and moderate values of n. 相似文献
9.
Cadmium poisoning poses a serious health concern due to cadmium''s increasing industrial use, yet there is currently no recommended treatment. The selective coordination of cadmium in a biological environment—i.e. in the presence of serum ions, small molecules, and proteins—is a difficult task. To address this challenge, a combinatorial library of peptoid-based ligands has been evaluated to identify structures that selectively bind to cadmium in human serum with minimal chelation of essential metal ions. Eighteen unique ligands were identified in this screening procedure, and the binding affinity of each was measured using metal titrations monitored by UV-vis spectroscopy. To evaluate the significance of each chelating moiety, sequence rearrangements and substitutions were examined. Analysis of a metal–ligand complex by NMR spectroscopy highlighted the importance of particular residues. Depletion experiments were performed in serum mimetics and human serum with exogenously added cadmium. These depletion experiments were used to compare and demonstrate the ability of these peptoids to remove cadmium from blood-like mixtures. In one of these depletion experiments, the peptoid sequence was able to deplete the cadmium to a level comparable to the reported acute toxicity limit. Evaluation of the metal selectivity in buffered solution and in human serum was performed to verify minimal off-target binding. These studies highlight a screening platform for the identification of metal–ligands that are capable of binding in a complex environment. They additionally demonstrate the potential utility of biologically-compatible ligands for the treatment of heavy metal poisoning. 相似文献
10.
Brady RM Hatzis E Connor T Street IP Baell JB Lessene G 《Organic & biomolecular chemistry》2012,10(27):5230-5237
The design of small molecules that mimic the BH3 domain and bind to Bcl-2 proteins has emerged as a promising approach to discovering novel anti-cancer therapeutics. We reveal the design and synthesis of conformationally constrained benzoylurea scaffolds as conformational probes. Central to helix mimicry, the intramolecular hydrogen bond in the benzoylurea plays a key role in the pre-organisation of the acyclic substrates for cyclisation via ring closing metathesis, providing efficient access to the constrained mimetics. 相似文献