A semiautomated electron backscatter diffraction technique for extracting reliable twin statistics

A framework has been developed for extracting reliable twin statistics from a deformed microstructure using crystallographic twin identification techniques with spatially correlated electron backscatter diffraction (EBSD) data. The key features of this analysis are the use of the mathematical definition of twin relationships, the inclination of the common K ₁ plane at a twin boundary, and the correct identification of the parent orientation in a parent/twin pair. Methods for identifying the parent in a parent/twin pair will be briefly discussed and compared. Twin area fractions are then categorized by operative twin systems, number of active twin variants in each system, and corrected twin widths. These statistics are reported here for α-zirconium samples deformed in quasi-static four-point bend beams and in a 100 m/s Taylor cylinder impact test. Analysis of the statistics also begins to reveal the roles that deformation rate and relative orientation of the boundary conditions to the material’s symmetry axes play in determining the twinning activity that accommodates the imposed boundary conditions. These improved twin statistics can help quantify the deformation processes in materials that deform by twinning as well as serve to provide better validation of proposed models of the deformation processes.     

Dependence of muscle VO2 on blood flow dynamics at onset of forearm exercise

The hypothesis that the rate of increase in muscle O2 uptake (VO2mus) at the onset of exercise is influenced by muscle blood flow was tested during forearm exercise with the arm either above or below heart level to modify perfusion pressure. Ten young men exercised at a power of approximately 2.2 W, and five of these subjects also worked at 1.4 W. Blood flow to the forearm was calculated from the product of blood velocity and cross-sectional area obtained with Doppler techniques. Venous blood was sampled from a deep forearm vein to determine O2 extraction. The rate of increase in VO2mus and blood flow was assessed from the mean response time (MRT), which is the time to achieve approximately 63% increase from baseline to steady state. In the arm below heart position during the 2.2-W exercise, blood flow and VO2mus both increased, with a MRT of approximately 30 s. With the arm above the heart at this power, the MRTs for blood flow [79.8 +/- 15.7 (SE)s] and VO2mus (50.2 +/- 4.0 s) were both significantly slower. Consistent with these findings were the greater increases in venous plasma lactate concentration over resting valued in the above heart position (2.8 +/- 0.4 mmol/l) than in the below heart position (0.9 +/- mmol/l). At the lower power, both blood flow and VO2mus also increased more rapidly with the arm below compared with above the heart. These data support the hypothesis that changes in blood flow at the onset of exercise have a direct effect on oxidative metabolism through alterations in O2 transport.     

Effect of profound hearing loss on a central auditory nucleus

The present study was designed to investigate the type and extent of degeneration occurring in the human central auditory system subsequent to profound hearing loss. The authors have examined the size of one population of neurons in the ventral cochlear nucleus in seven subjects with profound hearing loss (audiometric responses poorer than 90-100 dB HL). Six normal subjects, ages 35-78, were used as controls. Cell size in the hearing-impaired subjects ranged from normal to reduced by more than 50 percent. Two factors appear to contribute to the variability in cell size reduction. The correlation coefficient (Spearman rs) of cell size with duration of profound deafness was -0.48, indicating a moderate tendency for neurons to become smaller with longer periods of deafness. The correlation coefficient of cell size with number of surviving cochlear ganglion cells was 0.73, indicating a stronger tendency for neurons to be larger with greater eighth nerve innervation of the cochlear nucleus. Two cases of Scheibe degeneration showed the most severe degenerative change in the central auditory system.     

A longitudinal study of green-liver osteomyelitis complex in commercial turkeys

Two flocks of Nicholas tom turkeys from separate farms with histories of above-average condemnations for turkey green-liver osteomyelitis complex (TOC) were studied throughout a 16-week growout. Fifty birds from each farm were necropsied each week for 15 weeks, and birds that had green livers, osteomyelitis in the proximal tibia, or swollen joints were cultured for aerobic bacteria along with an equal number of control birds. At processing, TOC lesions and green livers were obtained for bacterial culture and histopathology. Green-liver-associated TOC was not observed until the turkeys were 9 or 10 weeks of age. The incidence of TOC was higher on one farm, which also had a higher incidence of airsacculitis, higher early and weekly mortality, seroconversion to Newcastle disease virus and Mycoplasma meleagridis, and significantly higher average body weights, relative spleen weights, and relative liver weights. Both farms had a high incidence of intestinal lesions and infestation with Ascaridia dissimilis. Histological evaluation of green livers revealed hyperplasia of bile ducts, dilation of sinusoids, and pigment-containing Kupffer's cells, some of which stained positive for iron. The bacterial isolates most frequently cultured from bones and livers were pleomorphic gram-variable coccobacilli, which grew visible colonies only after a series of subcultures and extended incubation.     

Esterified estrogens with and without methyltestosterone decrease arterial LDL metabolism in cynomolgus monkeys

OBJECTIVES: To assess retinal complications and to identify risk factors for retinal complications following aqueous shunt procedures. MATERIALS AND METHODS: Records of 38 consecutive aqueous shunt procedures that were performed on 36 patients at the Eye Institute of the Medical College of Wisconsin, Milwaukee, from June 1993 to March 1995 (minimum follow-up, 6 months) were reviewed. The mean +/- SD follow-up was 11.4 +/- 5.2 months (median, 10.5 months). RESULTS: Twelve patients (32%) had the following retinal complications: 4 serous choroidal effusions (10%) that required drainage, 3 suprachoroidal hemorrhages (8%), 2 vitreous hemorrhages (5%), 1 rhegmatogenous retinal detachment (3%), 1 endophthalmitis (3%), and 1 scleral buckling extrusion (3%). Surgical procedures for retinal complications were required in 8 (67%) of these 12 patients. Visual acuity decreased 2 lines or more in 9 (75%) of these 12 patients. The median onset of a postoperative retinal complication was 12.5 days, with 10 patients (83%) experiencing complications within 35 days. Serous choroidal effusions developed in 10 other patients (26%), and these effusions resolved spontaneously. Visual acuity decreased 2 lines or more in 2 (20%) of these additional 10 patients. Patients who experienced serious retinal complications were significantly older, had a higher rate of hypertension, and postoperative ocular hypotony. Serious retinal complications were distributed evenly among patients with Krupin valves with discs and Molteno and Baerveldt devices. Experience with the Ahmed glaucoma valve implant was limited. CONCLUSION: Aqueous shunt procedures may be associated with significant retinal complications and subsequent visual loss.     

The Xcad-2 gene can provide a ventral signal independent of BMP-4

Patterning of the marginal zone in the Xenopus embryo has been attributed to interactions between dorsal genes expressed in the organizer and ventral-specific genes. In this antagonistic interplay of activities, BMP-4, a gene that is not expressed in the organizer, provides a strong ventralizing signal. The Xenopus caudal type homeobox gene, Xcad-2, which is expressed around the blastopore with a gap over the dorsal lip, was analyzed as part of the ventral signal. Xcad-2 was shown to efficiently repress during early gastrula stages the dorsal genes gsc, Xnot-2, Otx-2, XFKH1 and Xlim-1, while it positively regulates the ventral genes, Xvent-1 and Xvent-2, with Xpo exhibiting a strong positive response to Xcad-2 overexpression. Xcad-2 was also capable of inducing BMP-4 expression in the organizer region. Support for a ventralizing role for Xcad-2 was obtained from co-injection experiments with the dominant negative BMP receptor which was used to block BMP-4 signaling. Under lack-of-BMP-signaling conditions Xcad-2 could still regulate dorsal and ventral gene expression and restore normal development, suggesting that it can act downstream of BMP-4 signaling or independently of it. Xcad-2 could also inhibit secondary axis formation and dorsalization induced by the dominant negative BMP receptor. Xcad-2 was also shown to efficiently reverse the dorsalizing effects of LiCl. These results place Xcad-2 as part of the ventralizing gene program which acts during early gastrula stages and can execute its ventralizing function in the absence of BMP signaling.     

Fractures of the patella in children and adolescents

Renal scarring is considered a criterion of reflux nephropathy and the end stage of pyelonephritis. Prednisolone, a strong anti-inflammatory drug, at doses of 1 or 2 mg/kg prevented renal scarring in rats following infection with Serratia marcescens. Four or 8 mg/kg of prednisolone, however, did not inhibit renal scar formation. In a time course experiment, renal scarring was prevented when 4-day treatment with prednisolone was initiated 2, 5, or 13 days after infection. These results show that prednisolone is effective in preventing such scarring and suggest the clinical use of this drug for preventing renal scar formation after pyelonephritis and reflux nephropathy.     

The Joint Evaluation Procedure for Active Substances contained in Plant Protection Products within the European Community – 10?Years of the ECCO-Project

Pflanzenschutzmittel müssen seit 1993 in den Mitgliedstaaten der Europ?ischen Gemeinschaft nach der Richtlinie 91/414/EWG des Rates bewertet und zugelassen werden. Das Programm zur Bewertung von alten Wirkstoffen (welche vor Juli 1993 auf dem Markt waren) beinhaltet mehrere Schritte und Stufen, die früher über einen Zeitraum von bis zu 10 Jahren zu bew?ltigen waren; heute sind dafür jedoch 15 Jahre vorgesehen. Das Programm wurde seit 1996 von der Europ?ischen Kommission mit Unterstützung des ECCO-Teams(European Community Co-Ordination) koordiniert. Das ECCO-Team bestand aus zwei Gruppen: eine im Pesticides Safety Directorate – PSD in York (Gro?britannien) und eine im Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (BVL) bzw. vor November 2002 in der Biologischen Bundesanstalt für Land- und Forstwirtschaft in Braunschweig. Sie unterstüzten das Programm zur Bewertung von Wirkstoffen im Namen der Kommission in technischer und administrativer Hinsicht und zeichneten sich insbesondere für das ECCO Peer Review Programm (Expertenprüfungen) verantwortlich. Im November 2003 übernahm die Europ?ische Beh?rde für Lebensmittelsicherheit (EFSA) die Verantwortung für die wissenschaftliche überprüfung der von den Mitgliedstaaten erstellten Bewertungen durch Experten. Das ECCO-Team leistete jedoch weiterhin der Europ?ischen Kommission Unterstützung bei der Durchführung anderer Verfahrensaspekte, vor allem im Bereich der Managementaufgaben der Europ?ischen Kommission. Insgesamt war das Programm au?erordentlich erfolgreich. Es wurden für 162 Wirkstoffen zwischen 1996 und 2003 der Inhalt der von den Mitgliedstaaten erstellten Bewertungsberichte durch eine Expertengruppe diskutiert und füberprüft, was ma?geblich eine Entscheidungsfindung zur Akzeptabilitf?t dieser Wirkstoffe auf Gemeinschaftsebene erm?glicht hat.     

On Linear Copositive Lyapunov Functions and the Stability of Switched Positive Linear Systems

We consider the problem of common linear copositive Lyapunov function existence for positive switched linear systems. In particular, we present a necessary and sufficient condition for the existence of such a function for switched systems with two constituent linear time-invariant systems. Several applications of this result are also given.