Search

Objectives The primary objective was to determine the diagnostic accuracy of a serial ultrasound (US) clinical diagnostic pathway to detect appendicitis in children presenting to the emergency department (ED). The secondary objective was to examine the diagnostic performance of the initial and interval US and to compare the accuracy of the pathway to that of the initial US. Methods This was a prospective cohort study of 294 previously healthy children 4 to 17 years old with suspected appendicitis and baseline pediatric appendicitis scores of ≥2, who were managed with the serial US clinical diagnostic pathway. This pathway consisted of an initial US followed by a clinical reassessment in each patient and an interval US and surgical consultation in patients with equivocal initial US and persistent concern about appendicitis. The USs were interpreted by published criteria as positive, negative, or equivocal for appendicitis. Children in whom this pathway did not rule in or rule out appendicitis underwent computed tomography (CT). Cases with missed appendicitis, negative operations, and CTs after the pathway were considered inaccurate. The primary outcome was the diagnostic accuracy of the serial US clinical diagnostic pathway. The secondary outcomes included the test performance of the initial and interval US imaging studies. Results Of the 294 study children, 111 (38%) had appendicitis. Using the serial US clinical diagnostic pathway, 274 of 294 children (93%, 95% confidence interval [CI] = 90% to 96%) had diagnostically accurate results: 108 of the 111 (97%) appendicitis cases were successfully identified by the pathway without CT scans (two missed and one CT), and 166 of the 183 (91%) negative cases were ruled out without CT scans (14 negative operations and three CTs). The sensitivity of this pathway was 108 of 111 (97%, 95% CI = 94% to 100%), specificity 166 of 183 (91%, 95% CI = 87% to 95%), positive predictive value 108 of 125 (86%; 95% CI = 79% to 92%), and negative predictive value 166 of 169 (98%, 95% CI = 96% to 100%). The diagnostic accuracy of the pathway was higher than that of the initial US alone (274 of 294 vs. 160 of 294; p

Semiconductor GaAs (100) was implanted with In+ at a room temperature. Fluences of implanted ions were from 1x 1012 cm-2 to 3x1013 cm-2 and the energy was equal to 85 keV. The detectability of the indium content in near surface layer of GaAs has been studied with the use of the secondary ion mass spectrometry (SIMS). The depths distribution of a indium concentration measured by SIMS method ware compared with depth profiles calculated with the help of SATVAL code. It was noticed that calculated profiles are in a good agreement with the measured values. Additionally, the concentration of indium in the near surface layer increased with growing of the implantation fluence and a maximum of these profiles shift in the side of ions exposed surfaces of GaAs. This effect can be explained by self-diffusion process of target atoms and indium during the implantation. The fractional derivative spectrum (FDS) model in connection with spectroscopic ellipsometry ES was used for particular optical analyses of implanted GaAs substrates. The FDS is especially promising technique when the limitations of the standard treatment by Lorentz shape line analysis occur and it is very helpful to extract basic information on relevant physical quantities from the detected eE2(E) spectra determined by spectroscopic ellipsometry. In particular, using spectroscopic ellipsometry and FDS, the critical points E1 and E1+Δ observed in the eE2(E) spectra in the implanted substrates have been investigated. The differences in complex refractive index and dielectric function (e=e1+ie2) between GaAs substrate before and implantation were observed. Moreover, the several nanometres thick oxide layer on GaAs surface was detected. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Puccinia graminis subsp. graminicola has caused economically important losses of tall fescue (Festuca arundinacea Schreb.) in North America. This rust infects leaves, culms, and spikelets of the host. Initital symptoms consist of very small, chlorotic flecks, followed by long, narrow lesions. Invasive hyphae were diffuse and filamentous, changing to dense and blocky with the formation of hymenia. Tissues were extensively colonized, including development caryopses. Seedborne infection consisted of mycelium within the embryo and urediniospores carried on both surfaces of the glumes. It is not known whether caryopses that are internally infected can germinate to produce infected individuals, but this could be an important quarantine consideration. Although, at the ultrastructural level, urediniospore development in this fungus is similar to that of other rusts, we detected an additional layer at the interface of the urediniospore and its pedicel. This layer may play a role in the, release of urediniospores from their pedicels.

The fungus Phomopsis phaseoli (Desmaz.) Sacc. (syn. P. sojae Lehman) incites a serious disease of soybean [Glycine max (L.) Merr.] seeds. This study was conducted to determine if an impermeable seed coat reduces infection by this fungus. Seeds of four soybean cultivars found in blotter tests to be infected by P. phaseoli in very low amounts (0-5%) and seeds of four other cultivars with high amounts of infection by this fungus (65-83%) were studied under scanning electron microscopy. Seed coats of cultivars with low P. phaseoli infection were found to lack pores, whereas those with high infection had multiple pores

Ion implanted gallium phosphide layers are studied by ellipsometry. Complex refractive indices of these layers are determined for a wide ion dose range. The characteristic behaviour of ellipse- metric parameters is observed as a function of increasing disorder, with creation of an amorphous layer for a certain dose value. Theoretical ellipsometric parameters are computed using a 3-phase model: i.e., an oxide surface layer, implanted layer, crystalline GaP substrate. The thicknesses of the damaged layers are estimated for the case of heavily bombarded GaP. [Russian Text Ignored].

Ellipsometric investigations are made of the kinetics of native oxide growth on GaAs crystals (100) implanted with Ar+ and Al+. The dependences of the thickness of the oxide on the time t is determined, where t denotes the exposition time of the sample to air. It is observed that the oxidation rate of the samples in air depends on the dose of ions implanted into the material. [Russian Text Ignored].

A new special research stand, co-operating with the implanter UNIMAS-79, is described. The way of using PIPE method (particle induced photon emission) for the determination of depth distribution of the concentration of metallic impurities in semiconductor crystals is presented. The range of application of this method and its limits are pointed out. A comparison of experimental data with theoretical evaluation is made. [Russian Text Ignored].

An ellipsometric experiment designed to determine the damage distribution produced by energetic heavy P ions in GaAs is described. GaAs (100) crystals are implanted with P+ ions of a dose of 1016 cm−2 and energies of 50, 90, 120, and 160 keV. Assuming an approximation based on the EMA theory, the concentration profiles of the amorphous phase in every etched layer are calculated. Then, these are compared with the theoretical total atom displacements, obtained with the Monte-Carlo calculations. The level of disorder in implanted layers is also calculated. The maxi mum of disorder of the implanted layers equals 0.95. [Russian Text Ignored].

Ellipsometric measurements of GaAs implanted with 100 and 180 keV Ar+ ions at doses in the range of 3 × 1013 to 1016 ions/cm2 are presented. The thicknesses of the amorphous GaAs layer and a transition layer as well as the distribution of the optical constants in the transition layer are calculated basing on the multilayer model. [Russian Text Ignored].