Family Signiphoridae (Chalcidoidea) in Egypt

Species of the family Signiphoridae (Chalcidoidea) are primarily hyperparasitoids associated with scale insects, whiteflies and mealybugs through other Chalcidoidea; however, certain species are primary parasitoids of these hosts. Recent collections and a review of the literature indicate that the following five species of the family Signiphoridae are known to occur in Egypt: Chartocerus niger (Ashmead), Chartocerus subaeneus (Főrster), Signiphora fax Girault, Thysanus sp. and Signiphora flavella Girault, the latter newly recorded in Egypt and Palearctic region. A key to the Egyptian signiphorid species is included

Different ways of dealing with Compton scattering and positron annihilation experimental data

Different ways of dealing with one-dimensional (1D) spectra, measured e.g. in the Compton scattering or angular correlation of positron annihilation radiation (ACAR) experiments are presented. On the example of divalent hexagonal close packed metals it is shown what kind of information on the electronic structure one can get from 1D profiles, interpreted in terms of either 2D or 3D momentum densities. 2D and 3D densities are reconstructed from merely two and seven 1D profiles, respectively. Applied reconstruction techniques are particular solutions of the Radon transform in terms of orthogonal Gegenabauer polynomials. We propose their modification connected with so-called two-step reconstruction. The analysis is performed both in the extended p and reduced k zone schemes. It is demonstrated that if positron wave function or many-body effects are strongly momentum dependent, analysis of 2D densities folded into k space may lead to wrong conclusions concerning the Fermi surface. In the case of 2D ACAR data in Mg we found very strong many-body effects. PACS numbers: 71.18.+y, 13.60.Fz, 87.59.FmComment: 17 pages, 9 figure

Future of 5-fluorouracil in cancer therapeutics, current pharmacokinetics issues and a way forward

Background: In addition to exhibiting antitumor potential, antitumor drugs exhibit toxicity due to a poor pharmacokinetic profile. An enormous amount of research has been carried out and is still ongoing to obtain more targeted, potent, and safe drugs to treat cancer, and pharmacokinetic evaluations of anticancer drugs are needed. Objectives: The present review examined different delivery systems and methodologies designed in recent years to investigate the pharmacokinetics of the anticancer drug, 5-fluorouracil (5-FU). These methodologies highlight how the issues of bioavailability, absorption, half-life, targeted neoplastic cell potential, and high therapeutic index of 5-FU are resolved. Results: A number of naturally occurring macromolecules such as modified starch, porphyran, peptides, and folic acids have been found to be successful in vitro to improve the permeability and retention effect of 5-FU against solid tumors. A promising approach for targeted 5-FU delivery to oncoproteins has resulted in a number of potentially sound anticancer nanocomposites. Chitosan nanoparticles loaded with 5-FU have been shown to exhibit cytotoxicity equivalent to 5-FU injections against gastric carcinoma. At the level of inter- and intra-molecular interactions, the co-crystal approach has been found to be successful against colorectal cancer proteins. Because of the 5-FU ligand-like nature and its metal-binding potential, researchers have shifted attention toward the synergistic co-administration of gold complexes with this drug. Conclusions: This study highlighted the techniques used to improve the pharmacokinetics of 5-FU and that “nanocarriers” are a promising approach in this field. The conclusion is supported by solid evidence

ExTrA: Exoplanets in Transit and their Atmospheres

The ExTrA facility, located at La Silla observatory, will consist of a near-infrared multi-object spectrograph fed by three 60-cm telescopes. ExTrA will add the spectroscopic resolution to the traditional differential photometry method. This shall enable the fine correction of color-dependent systematics that would otherwise hinder ground-based observations. With both this novel method and an infrared-enabled efficiency, ExTrA aims to find transiting telluric planets orbiting in the habitable zone of bright nearby M dwarfs. It shall have the versatility to do so by running its own independent survey and also by concurrently following-up on the space candidates unveiled by K2 and TESS. The exoplanets detected by ExTrA will be amenable to atmospheric characterisation with VLTs, JWST, and ELTs and could give our first peek into an exo-life laboratory.Comment: 15 pages, 11 figures, SPIE 201

Discretized aperture mapping with a micro-lenses array for interferometric direct imaging

Discretized Aperture Mapping (DAM) appears as an original filtering technique easy to play with existing adaptive optics (AO) systems. In its essential DAM operates as an optical passive filter removing part of the phase residuals in the wavefront without introducing any difficult-to-align component in the Fourier conjugate of the entrance pupil plane. DAM reveals as a new interferometric technique combined with spatial filtering allowing direct imaging over a narrow field of view (FOV). In fact, the entrance pupil of a single telescope is divided into many sub-pupils so that the residual phase in each sub-pupil is filtered up to the DAM cut-off frequency. DAM enables to smooth the small scale wavefront defects which correspond to high spatial frequencies in the pupil plane and to low angular frequencies in the image plane. Close to the AO Nyquist frequency, such pupil plane spatial frequencies are not well measured by the wavefront sensor (WFS) due to aliasing. Once bigger than the AO Nyquist frequency, they are no more measured by the WFS due to the fitting limit responsible for the narrow AO FOV. The corresponding image plane angular frequencies are not transmitted by DAM and are useless to image small FOVs, as stated by interferometry. That is why AO and DAM are complementary assuming that the DAM cut-off frequency is equal to the AO Nyquist frequency. Here we describe the imaging capabilities when DAM is placed downstream an AO system, over a convenient pupil which precedes the scientific detector. We show firstly that the imaging properties are preserved on a narrow FOV allowing direct imaging throughout interferometry. Then we show how the residual pupil plane spatial frequencies bigger than the AO Nyquist one are filtered out, as well as the residual halo in the image is dimmed

A narrow, edge-on disk resolved around HD 106906 with SPHERE

HD~106906AB is so far the only young binary system around which a planet has been imaged and a debris disk evidenced thanks to a strong IR excess. As such, it represents a unique opportunity to study the dynamics of young planetary systems. We aim at further investigating the close (tens of au scales) environment of the HD~106906AB system. We used the extreme AO fed, high contrast imager SPHERE recently installed on the VLT to observe HD~106906. Both the IRDIS imager and the Integral Field Spectrometer were used. We discovered a very inclined, ring-like disk at a distance of 65~au from the star. The disk shows a strong brightness asymmetry with respect to its semi-major axis. It shows a smooth outer edge, compatible with ejection of small grains by the stellar radiation pressure. We show furthermore that the planet's projected position is significantly above the disk's PA. Given the determined disk inclination, it is not excluded though that the planet could still orbit within the disk plane if at a large separation (2000--3000 au). We identified several additional point sources in the SPHERE/IRDIS field-of-view, that appear to be background objects. We compare this system with other debris disks sharing similarities, and we briefly discuss the present results in the framework of dynamical evolution.Comment: 7 pages, 6 figures, accepted by Astronomy & Astrophysic

The efficacy of indigenous and imported predators utilized in the biological control of Bemisia tabaci biotype „B” (Homoptera: Aleyrodidae) in greenhouse

The silver leaf whitefly,Bemisia tabaci biotype „B ”(Homoptera:Aleyrodidae)is one of the most serious vegetable and ornamental plants pest in Egypt.Predators play an important role in controlling this species. The present work deals with the abundance of indigenous predators in greenhouse on three host plants mostly of vegetable crops during April –July,1996.Chrysoperla carnea (Stephens)(Neuropteran: Chrysopidae)is considered the most abundant predator acting on Bemisia. In the meantime,the work deals also with the potential of the imported predators,namely Delphastus pusillus Le Conte (Coleoptera:Coccinellidae)and Macrophillus caliginosus (Wagner)(Hemip- tera :Miridae).These predators were released 3 times on eggplant (Solanum melongena)and at the ratio of 1 individual and 2 individuals/plant for D.pusillus and M.caliginosus,respectively.Results indicate that predators increased in numbers while whitefly population decreased in comparison to control homologues. Biotype B.tabaci was identified in John Innes Center,UK and recorded by Abd-Rabou (1999) in Egypt as first recorded for presence of this biotype