Direct detection of electron backscatter diffraction patterns.

We report the first use of direct detection for recording electron backscatter diffraction patterns. We demonstrate the following advantages of direct detection: the resolution in the patterns is such that higher order features are visible; patterns can be recorded at beam energies below those at which conventional detectors usefully operate; high precision in cross-correlation based pattern shift measurements needed for high resolution electron backscatter diffraction strain mapping can be obtained. We also show that the physics underlying direct detection is sufficiently well understood at low primary electron energies such that simulated patterns can be generated to verify our experimental data

Use of Electron Back Scatter Diffraction Patterns for Determination of Crystal Symmetry Elements

The application of electron back scatter diffraction in the scanning electron microscope has been extended to the determination of crystal symmetry elements, point group and space group. The wide angular range of the patterns makes this a relatively simple task compared with equivalent analysis using electron channelling patterns, convergent beam patterns or standard x-ray methods, though the complexity of the analysis does not permit an unthinking approach. To establish the best procedure specimens from the seven crystal systems were investigated and results from the examination of the metal tin (tetragonal), and minerals zircon (ZrSiO4, tetragonal) and calcite (CaCO3 rhombohedral) are presented. The procedure entails determination of the crystal system from detection of rotation axes, determination of point group from the observed combinations of mirror planes and rotation axes, determination of Bravais lattice, and finally, determination of space group from the absences of lines due to screw axes and glide planes. Considerable computational aids were required in the latter stages of analysis and for this a computer program was written to simulate the diffraction patterns from any crystal system and Bravais lattice with line delete procedures to remove lines forbidden because of space group requirements

On-Line Analysis of Electron Back Scatter Diffraction Patterns. I. Texture Analysis of Zone Refined Polysilicon

A technique has been developed for determining crystal orientations on-line from bulk polycrystalline materials using wide angle back scatter electron diffraction patterns. The patterns were imaged on a phosphor screen and viewed using a low light level television camera. A computer generated cursor superimposed on the diffraction pattern, permitted the coordinates of zone axes to be determined. These were interpreted by the computer to yield the crystal orientation. The accuracy of the technique for absolute orientation was shown to be of the order 1° and the precision for relative orientation better than 0.5°. The technique was used to investigate texture and nearest neighbour orientation relationships in polysilicon, recrystallised using a graphite strip heater technique. It was shown that the orientations become less random as the recrystallisation front proceeded along the specimen

Diffractive triangulation of radiative point sources

We describe a general method to determine the location of a point source of waves relative to a twodimensional single-crystalline active pixel detector. Based on the inherent structural sensitivity of crystalline sensor materials, characteristic detector diffraction patterns can be used to triangulate the location of a wave emitter. The principle described here can be applied to various types of waves, provided that the detector elements are suitably structured. As a prototypical practical application of the general detection principle, a digital hybrid pixel detector is used to localize a source of electrons for Kikuchi diffraction pattern measurements in the scanning electron microscope. This approach provides a promising alternative method to calibrate Kikuchi patterns for accurate measurements of microstructural crystal orientations, strains, and phase distributions

Bullet and Shrapnel Embolism: When “Uncommon” Meets “Dangerous”

Bullet and shrapnel embolism (BSE) is well described in the literature. Despite that, its rare occurrence creates a diagnostic challenge for providers tending to penetrating trauma victims. As with other forms of embolic phenomena, cases of BSE require a blend of superb clinical expertise and experience, as well as a high diagnostic index of suspicion. Management is highly individualized and spans a broad spectrum of options from “watchful waiting” to open heart surgery. Due to the risk of retained projectile migration through tissues, including erosion into surrounding anatomic structures, non-operative approaches warrant long-term clinical surveillance. When promptly recognized and treated appropriately, patients with BSE can be expected to have excellent clinical outcomes

Real-Time Measurement of Xenon Concentration in a Binary Gas Mixture Using a Modified Ultrasonic Time-of-Flight Anesthesia Gas Flowmeter

Background: Xenon (Xe) is an anesthetic gas which may have potential as a neuroprotectant. To measure each gas in a xenon/oxygen mixture one would typically use a thermal conductivity meter and a fuel cell respectively. The speed of sound in a binary gas mixture like this is related to fractional concentration, temperature, pressure, and masses of the gases present. We assessed the feasibility of developing a novel single sterilizable device which used the time of flight of ultrasound through the gas to measure both real-time gas flow and also the concentration of Xe in O2.Method: We adapted an ultrasonic time-of-flight flow meter from a conventional anesthetic machine to also measure the real time fractional concentration of Xe in O2. A total of 5 095 readings of were taken in the range 5 % to 95 % xenon, and compared with simultaneous measurements from a commercially available thermal conductivity xenon analyser.Results: Ultrasonic measurements of Xe (%) showed agreement with thermal conductivity meter measurements but there was marked discontinuity in the central region of the measurement range. Bland-Altman analysis (95% CI): Mean Difference (Bias) 3.1 (2.9 % to 3.2 %); lower 95 % Limit of Agreement -4.6 % (-4.8 % to -4.4 %); upper 95 % Limit of Agreement 10.8 % (10.5 % to 11.0 %).Conclusions: The modified ultrasonic flow meter estimated the Xe (%) however at present the accuracy is not sufficient for clinical use. With further work it may be possible to improve the accuracy sufficiently for potential clinical use

Foreign Intravascular Object Embolization and Migration: Bullets, Catheters, Wires, Stents, Filters, and More

Foreign intravascular object embolization (FIOE) is an important, yet underreported occurrence that has been described in a variety of settings, from penetrating trauma to intravascular procedures. In this chapter, the authors will review the most common types of FIOEs, including bullet or “projectile” embolism (BPE), followed by intravascular catheter or wire embolization (ICWE), and conclude with intravascular noncatheter object (e.g., coil, gelatin, stent, and venous filter) migration (INCOM). In addition to detailed topic-based summaries, tables highlighting selected references and case scenarios are also presented to provide the reader with a resource for future research in this clinical area

Causes of death in Vanuatu

Background The population of the Pacific Melanesian country of Vanuatu was 234,000 at the 2009 census. Apart from subsistence activities, economic activity includes tourism and agriculture. Current completeness of vital registration is considered too low to be usable for national statistics; mortality and life expectancy (LE) are derived from indirect demographic estimates from censuses/surveys. Some cause of death (CoD) data are available to provide information on major causes of premature death. Methods Deaths 2001–2007 were coded for cause (ICDv10) for ages 0–59 years from: hospital separations (HS) (n = 636), hospital medical certificates (MC) of death (n = 1,169), and monthly reports from community health facilities (CHF) (n = 1,212). Ill-defined causes were 3 % for hospital deaths and 20 % from CHF. Proportional mortality was calculated by cause (excluding ill-defined) and age group (0–4, 5–14 years), and also by sex for 15–59 years. From total deaths by broad age group and sex from 1999 and 2009 census analyses, community deaths were estimated by deduction of hospital deaths MC. National proportional mortality by cause was estimated by a weighted average of MC and CHF deaths. Results National estimates indicate main causes of deaths <5 years were: perinatal disorders (45 %) and malaria, diarrhea, and pneumonia (27 %). For 15–59 years, main causes of male deaths were: circulatory disease 27 %, neoplasms 13 %, injury 13 %, liver disease 10 %, infection 10 %, diabetes 7 %, and chronic respiratory disease 7 %; and for females: neoplasms 29 %, circulatory disease 15 %, diabetes 10 %, infection 9 %, and maternal deaths 8 %. Infection included tuberculosis, malaria, and viral hepatitis. Liver disease (including hepatitis and cancer) accounted for 18 % of deaths in adult males and 9 % in females. Non-communicable disease (NCD), including circulatory disease, diabetes, neoplasm, and chronic respiratory disease, accounted for 52 % of premature deaths in adult males and 60 % in females. Injuries accounted for 13 % in adult males and 6 % in females. Maternal deaths translate into an annual maternal mortality ratio of 130/100,000 for the period. Conclusion Vanuatu manifests a double burden of disease with significant proportional mortality from perinatal disorders and infection/pneumonia <5 years and maternal mortality, coupled with significant proportional mortality in adults (15–59 years) from cardiovascular disease (CVD), neoplasms, and diabetes

Functional diversity can facilitate the collapse of an undesirable ecosystem state

Biodiversity may increase ecosystem resilience. However, we have limited understanding if this holds true for ecosystems that respond to gradual environmental change with abrupt shifts to an alternative state. We used a mathematical model of anoxic–oxic regime shifts and explored how trait diversity in three groups of bacteria influences resilience. We found that trait diversity did not always increase resilience: greater diversity in two of the groups increased but in one group decreased resilience of their preferred ecosystem state. We also found that simultaneous trait diversity in multiple groups often led to reduced or erased diversity effects. Overall, our results suggest that higher diversity can increase resilience but can also promote collapse when diversity occurs in a functional group that negatively influences the state it occurs in. We propose this mechanism as a potential management approach to facilitate the recovery of a desired ecosystem state

Inflammation and Atrophy Precede Prostate Neoplasia in PhIP Induced Rat Model

2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) has been implicated as a major mutagenic heterocyclic amine in the human diet and is carcinogenic in the rat prostate. In order to validate PhIP induced rat prostate neoplasia as a model of human prostate cancer progression, we sought to study the earliest histologic and morphologic changes in the prostate and to follow the progressive changes over time. We fed 67 male Fischer F344 5 week old rats with PhIP (400 PPM) or control diets for 20 weeks, and then sacrificed animals for histomorphologic examination at age 25 weeks, 45 weeks, and 65 weeks. Animals treated with PhIP showed significantly more inflammation (P=.002 (25wk), &gt;.001(45wk), .016(65wk)) and atrophy (P=.003(25wk), &gt;.001(45wk), .006 (65wk)) in their prostate glands relative to controls. Prostatic intraepithelial neoplasia (PIN) occurred only in PhIP treated rats. PIN lesions arose in areas of glandular atrophy, most often in the ventral prostate. Atypical cells in areas of atrophy show loss of glutathione S-transferase pi immunostaining preceding development of PIN. None of the animals in this study developed invasive carcinomas differing from previous reports. Overall, these findings suggest that the pathogenesis of prostatic neoplasia in the PhIP treated rat prostate proceeds from inflammation to post-inflammatory proliferative atrophy to PIN