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61.
Antifungal activity of volatile fractions of essential oils from four aromatic wild plants in israel 总被引:2,自引:0,他引:2
Moshe Shimoni Eli Putievsky Uzi Ravid Reuven Reuveni 《Journal of chemical ecology》1993,19(6):1129-1133
Essential oils were extracted fromMajorana syriaca, Satureja thymbra, Micromeria fruticosa, andSalvia triloba, and their volatile fractions were tested for their antifungal activity against the soil-borne pathogensFusarium oxysporum andMacrophomina phaseolina and the foliar pathogensBotrytis cinerea andExserohilum turcicum. Results showed a fungistatic effect of 1, 2.5, and 5l of the various essential oils on fungal mycelium growth. The most significant effect was exerted by essential oils extracted fromM. syriaca, which inhibited the growth ofB. cinerea by 44% and of all the other fungi tested by 100%.Contribution from the Agricultural Research Organization, the Volcani Center, Bet Dagan, Israel. No. 3555-E, 1992 series. 相似文献
62.
Vasilis Pagonis Grzegorz AdamiecC. Athanassas Reuven ChenAtlee Baker Meredith LarsenZachary Thompson 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(12):1431-1443
Thermally-transferred optically stimulated luminescence (TT-OSL) signals in sedimentary quartz have been the subject of several recent studies, due to the potential shown by these signals to increase the range of luminescence dating by an order of magnitude. Based on these signals, a single aliquot protocol termed the ReSAR protocol has been developed and tested experimentally. This paper presents extensive numerical simulations of this ReSAR protocol. The purpose of the simulations is to investigate several aspects of the ReSAR protocol which are believed to cause difficulties during application of the protocol. Furthermore, several modified versions of the ReSAR protocol are simulated, and their relative accuracy and precision are compared. The simulations are carried out using a recently published kinetic model for quartz, consisting of 11 energy levels. One hundred random variants of the natural samples were generated by keeping the transition probabilities between energy levels fixed, while allowing simultaneous random variations of the concentrations of the 11 energy levels. The relative intrinsic accuracy and precision of the protocols are simulated by calculating the equivalent dose (ED) within the model, for a given natural burial dose of the sample. The complete sequence of steps undertaken in several versions of the dating protocols is simulated. The relative intrinsic precision of these techniques is estimated by fitting Gaussian probability functions to the resulting simulated distribution of ED values. New simulations are presented for commonly used OSL sensitivity tests, consisting of successive cycles of sample irradiation with the same dose, followed by measurements of the sensitivity corrected L/T signals. We investigate several experimental factors which may be affecting both the intrinsic precision and intrinsic accuracy of the ReSAR protocol. The results of the simulation show that the four different published versions of the ReSAR protocol can reproduce accurately the natural doses in the range 0-400 Gy with approximately the same intrinsic precision and accuracy of ∼1-5%. However, these protocols underestimate doses above 400 Gy; possible sources of this underestimation are investigated. Two possible explanations are suggested for the modeled underestimations, possible thermal instability of the TT-OSL traps, and the presence of thermally unstable medium OSL components in the model. 相似文献
63.
A two-phase analytic approach to robotic system design is presented. The first phase evaluates the robotic technological classes according to their functional adequacy; the next phase specifies the desired robotic configuration. The methodology developed here is demonstrated for the case of installing a robot in an automated investment casting shelling production line. 相似文献
64.
Frant J Veerendhar A Chernilovsky T Nedvetzki S Vaksman O Hoffman A Breuer E Reich R 《ChemMedChem》2011,6(8):1471-1477
Seven 4‐phenoxybenzenesulfonamidopolymethylene carbamoylphosphonates (CPOs) bearing two to eight methylene units in the polymethylene chain were synthesized and evaluated as matrix metalloproteinase (MMP) inhibitors. The five lowest homologues [(CH2)2?6] are selective MMP‐2 inhibitors, whereas the two with the longest linkers [(CH2)7, 8] lack inhibitory activity. The most potent homologues are those with (CH2)5, 6; these two were evaluated for antimetastatic activity in a murine melanoma model and showed good potency both by oral and intraperitoneal administration without any toxic—including musculoskeletal—side effects. In contrast to the previously reported cis‐ACCP, which was shown to inhibit MMP‐2 for ~30 min, the new compounds inhibit MMP activity for the duration of measurement, lasting several hours. Pharmacokinetic evaluation revealed, on the one hand, low oral bioavailability; on the other hand, a relatively large calculated volume of distribution, consistent with the observed reversible absorption of CPO 5 to hydroxyapatite, as a model for bone. 相似文献
65.
Aleksey Etin Gennady E. Shter Reuven Brener Sioma Baltianski Gideon S. Grader 《Journal of the American Ceramic Society》2007,90(12):3800-3803
Reports on PZT films often suggest the contradicting presence of Pb-deficient pyrochlore (Py) and a Pb-rich layer on the surface. We show that standard Ar+ ion sputtering X-ray photoelectron spectroscopy (XPS) depth profiles of PZT films artificially exhibit a Pb-rich surface, independent of actual Pb content of the chemical solution deposition solution. However angle-resolved XPS measurements reveal that films derived from solutions with 10% Pb excess, which give rise to Py surface grains, actually have the expected Pb-deficient surface layer. Alternatively, films derived from solutions with 30% Pb excess are Py free and have Pb-rich surface layer. The Pb-rich films show an increased imprint effect with increasing Pb content. 相似文献
66.
Reuven I. Be'ery Y. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1998,44(2):580-598
The trellis representation of nonlinear codes is studied from a new perspective. We introduce the new concept of entropy/length profile (ELP). This profile can be considered as an extension of the dimension/length profile (DLP) to nonlinear codes. This elaboration of the DLP, the entropy/length profiles, appears to be suitable to the analysis of nonlinear codes. Additionally and independently, we use well-known information-theoretic measures to derive novel bounds on the minimal covering of a bipartite graph by complete subgraphs. We use these bounds in conjunction with the ELP notion to derive both lower and upper bounds on the state complexity and branch complexity profiles of (nonlinear) block codes represented by any trellis diagram. We lay down no restrictions on the trellis structure, and we do not confine the scope of our results to proper or one-to-one trellises only. The basic lower bound on the state complexity profile implies that the state complexity at any given level cannot be smaller than the mutual information between the past and the future portions of the code at this level under a uniform distribution of the codewords. We also devise a different probabilistic model to prove that the minimum achievable state complexity over all possible trellises is not larger than the maximum value of the above mutual information over all possible probability distributions of the codewords. This approach is pursued further to derive similar bounds on the branch complexity profile. To the best of our knowledge, the proposed upper bounds are the only upper bounds that address nonlinear codes. The novel lower bounds are tighter than the existing bounds. The new quantities and bounds reduce to well-known results when applied to linear codes 相似文献
67.
Typically, the term “high speed drilling” is related to spindle capability of high cutting speeds. The suggested high speed drilling machine (HSDM) extends this term to include very fast and accurate point-to-point motions. The new HSDM is composed of a planar parallel mechanism with two linear motors as the inputs. The paper is focused on the kinematic and dynamic synthesis of this parallel kinematic machine (PKM). The kinematic synthesis introduces a new methodology of input motion planning for ideal drilling operation and accurate point-to-point positioning. The dynamic synthesis aims at reducing the input power of the PKM using a spring element. 相似文献
68.
Moshe Laifenfeld Ari Trachtenberg Reuven Cohen David Starobinski 《Mobile Networks and Applications》2009,14(4):415-432
Wireless Sensor Networks (WSNs) provide an important means of monitoring the physical world, but their limitations present
challenges to fundamental network services such as routing. In this work we utilize an abstraction of WSNs based on the theory
of identifying codes. This abstraction has been useful in recent literature for a number of important monitoring problems,
such as localization and contamination detection. In our case, we use it to provide a joint infrastructure for efficient and
robust monitoring and routing in WSNs. Specifically, we make use of efficient and distributed algorithm for generating robust
identifying codes, an NP-hard problem, with a logarithmic performance guarantee based on a reduction to the set k-multicover problem. We also show how this same identifying-code infrastructure provides a natural labeling that can be used
for near-optimal routing with very small routing tables. We provide experimental results for various topologies that illustrate
the superior performance of our approximation algorithms over previous identifying code heuristics. 相似文献
69.
Direct position determination of cyclostationary signals 总被引:1,自引:0,他引:1
Direct position determination (DPD) was recently proposed as a new method for passive localization of narrowband radio transmitters. Its superior performance, especially in the low signal-to-noise ratio (SNR) regime, is ascribed to both the joint optimization it performs over all base stations that participate in the estimation process and the direct determination of the emitter position as opposed to conventional methods which typically process the information from the individual base stations separately and determine the location using two estimation steps.In this paper, we introduce the cyclic direct position determination (CDPD) algorithm, a novel method which is the cyclostationary counterpart of the DPD. Despite its name, the CDPD is not a simple extension of the DPD but a unique algorithm which deviates substantially from its ancestor. Yet, the CDPD enjoys both the benefits of the DPD algorithm and the great performance robustness in the presence of narrowband interferences thanks to its cyclostationarity exploitation. 相似文献
70.
This paper proposes a distributed handover protocol for a micro-cell packet switched mobile network. In such a network, users move from one cell to another very often, and each change of location may result in misrouted and lost packets. The purpose of the new protocol is to minimize these consequences of location changes: as long as a mobile moves from one cell to another but stays in the same region, the protocol avoids loss of packets and preserves order of transmission. Thus it increases the performance of the transport layer protocol by minimizing the need to retransmit packets.Previous version of the paper appreared in Infocom '95, April 1995, Boston, MA. 相似文献