Phase-contrast imaging using a scanning-double-grating configuration.

A new double-grating-based phase-contrast imaging technique is described. This technique differs from the conventional double-grating imaging method by the image acquisition strategy. The novelty of the proposed method is in lateral scanning of both gratings simultaneously while an image is collected.

Some simple rules for contrast, signal-to-noise and resolution in in-line x-ray phase-contrast imaging.

Simple analytical expressions are derived for the spatial resolution, contrast and signal-to-noise in X-ray projection images of a generic phase edge. The obtained expressions take into account the maximum phase shift generated by the sample and the sharpness of the edge, as well as such parameters of the imaging set-up as the wavelength spectrum and the size of the incoherent source, the source-to-object and object-to-detector distances and the detector resolution. Different asymptotic behavior of the expressions in the cases of large and small Fresnel numbers is demonstrated.

Experiences of nurses working in a stroke rehabilitation unit.

Aim: This paper is a report of a study to explore the perceptions, beliefs and feelings of a group of nurses who provided care to individuals admitted to a stroke rehabilitation unit.

Background: Following a stroke, survivors should ideally be referred to multidisciplinary inpatient rehabilitation programmes, which attain better outcomes compared to the care provided on general medical wards. However, to achieve these outcomes, team members must work closely together.

Participation among women living with HIV: a rehabilitation perspective.

The purpose of this phenomenological study was to understand the lived experience of women living with HIV using a rehabilitation lens. Twenty-three women with a mean age of 40.8 years participated in personal interviews regarding barriers and facilitators to participation in society.

Interaction with factor inhibiting HIF-1 defines an additional mode of cross-coupling between the Notch and hypoxia signaling pathways.

Cells adapt to hypoxia by a cellular response, where hypoxia-inducible factor 1alpha (HIF-1alpha) becomes stabilized and directly activates transcription of downstream genes. In addition to this "canonical" response, certain aspects of the pathway require integration with Notch signaling, i.e.

Soft tissue small avascular tumor imaging with x-ray phase-contrast micro-CT in-line holography.

To assess the feasibility of small soft tissue avascular tumor micro-CT imaging with x-ray phase-contrast in-line holography, we have studied micro-CT imaging with in-line geometry of small spheroidal avascular tumor models with quiescent cell core (< 250 mum) and various distributions of the proliferating cell density (PCD) forming the outer shell. We have simulated imaging with an ultrafast laser-based x-ray source with a Mo target. We observe phase-contrast enhancement of the tumor boundaries in the reconstructed transaxial images, resulting in improved detection of small soft tissue tumors, providing that the PCD density gradient is sufficiently large.

Development of ultrafast laser-based x-ray in-vivo phase-contrast micro-CT beamline for biomedical applications at Advanced Laser Light Source (ALLS).

We are developing and exploring the imaging performance of, an in vivo, in-line holography, x-ray phase-contrast, micro-CT system with an ultrafast laser-based x-ray (ULX) source. By testing and refining our system, and by performing computer simulations, we plan to improve system performance in terms of contrast resolution and multi-energy imaging to a level beyond what can be obtained using a conventional microfocal x-ray tube. Initial CT projection sets at single energy (Mo K(alpha) and K(beta) lines) were acquired in the Fresnel regime and reconstructed for phantoms and a euthanized mouse.

Mtx2 directs zebrafish morphogenetic movements during epiboly by regulating microfilament formation.

The homeobox transcription factor Mtx2 is essential for epiboly, the first morphogenetic movement of gastrulation in zebrafish. Morpholino knockdown of Mtx2 results in stalling of epiboly and lysis due to yolk rupture. However, the mechanism of Mtx2 action is unknown.

Vibrio harveyi sepsis in a child with cancer.

A paediatric oncology patient presented with central line sepsis caused by Vibrio harveyi, a gram negative bioluminescent marine bacterium known to be pathogenic to fish and marine invertebrates, after swimming in the sea.

The incidence of honey bee pests and diseases in England and Wales.

The Central Science Laboratory (CSL) National Bee Unit (NBU) has been responsible for maintaining the Integrated Bee Health Programme in England and Wales since the early 1990s. The role of the Bee Health Programme is to protect the honey bee, a major pollinator of agricultural and horticultural crops and wild flora, and to provide up-to-date technical support to beekeepers. The Bee Health Programme is funded in England by the Department for Environment, Food and Rural Affairs (Defra) and in Wales by the Welsh Assembly Government (WAG).

Modelling long-term effects of IGRs on honey bee colonies.

Systems have been developed to monitor the direct effects of insect growth regulator (IGR) pesticide exposure on honey bee development, but there has been little work on the longer-term impact of exposure on the colony. A honey bee population model provided the opportunity to investigate the effects of short-term mortality of brood and of sublethal changes in behaviour of the surviving adults on honey bee populations. The model showed that brood mortality alone has limited effect on colony size.

Elevated iron absorption in the neonatal rat reflects high expression of iron transport genes in the distal alimentary tract.

Intestinal iron absorption is extremely high in neonatal mammals but falls rapidly to adult levels following weaning. The aim of this study was to investigate the molecular basis of this elevated neonatal absorption using the rat as an experimental model. RNA was extracted from various sections of the intestine of 10-, 15-, 20-, 25-, and 300-day-old rats and the expression of the genes encoding DMT1 (Slc11a2), ferroportin (Slc40a1), Cybrd1 (Cybrd1), and hephaestin (heph) determined by ribonuclease protection assay.

Computed tomography with linear shift-invariant optical systems.

Optical systems capable of three-dimensional transmission imaging are considered; these systems employ a conventional tomographic setup with an added linear shift-invariant optical system between the sample and the detector. A theoretical analysis is presented of image formation and sample reconstruction in such systems, examples of which include diffraction tomography and phase-contrast tomography with the use of analyzer crystals. An example is introduced in which the image is obtained by scanning the beam along the line orthogonal to the optic axis and to the axis of rotation with a one-dimensional slit or grating parallel to the rotation axis.

ID20: a beamline for magnetic and resonant X-ray scattering investigations under extreme conditions.

A new experimental station at ESRF beamline ID20 is presented which allows magnetic and resonant X-ray scattering experiments in the energy range 3-25 keV to be performed under extreme conditions. High magnetic field up to 10 T, high pressure up to 30 kbar combined with low temperatures down to 1.5 K are available and experiments can be performed at the M-edges of actinide elements, L-edges of lanthanides and K-edges of transition metals.

A laboratory based system for laue micro x-ray diffraction.

A laboratory diffraction system capable of illuminating individual grains in a polycrystalline matrix is described. Using a microfocus x-ray source equipped with a tungsten anode and prefigured monocapillary optic, a micro-x-ray diffraction system with a 10 microm beam was developed. The beam profile generated by the ellipsoidal capillary was determined using the "knife edge" approach.

Work organization and its effects on the health of Chinese workers with English as a second language: a qualitative approach.

Work organization consists of three contexts: (a) the external context/factors, (b) the organizational context/practices, and, (c) the work context/process. The investigation of work organization may lead to more effective prevention and intervention for work-related injury and illness. Studies have suggested that workers with limited English proficiency may be more prone to work-related injury and illness.

Regulation of systemic iron homeostasis: how the body responds to changes in iron demand.

The iron that is required to meet the metabolic needs of cells and tissues is derived from the plasma. Plasma iron in turn reflects the release of iron from various body cells, principally the macrophages of the reticuloendothelial system, and the absorption of dietary iron by the proximal small intestine. This iron donation is highly regulated and the liver-derived peptide hepcidin has emerged as the key modulator of cellular iron export.

Edge plane sites on highly ordered pyrolytic graphite as templates for making palladium nanowires via electrochemical decoration.

An approach for the fabrication of metal nanowires is presented. Palladium wires with diameters less than 50 nm were produced by electrochemical decoration of step edge sites on the surface of highly ordered pyrolytic graphite via the following three steps. First an electrochemical activation step was used to oxidize the edge plane sites on highly ordered pyrolytic graphite surfaces in 0.

Determination of the antiferroquadrupolar order parameters in UPd(3).

By combining accurate heat capacity and x-ray resonant scattering results we have resolved the long standing question regarding the nature of the quadrupolar ordered phases in UPd(3). The order parameter of the highest temperature quadrupolar phase has been uniquely determined to be antiphase Q{zx} in contrast to the previous conjecture of Q{x{2}-y{2}}. The azimuthal dependence of the x-ray scattering intensity from the quadrupolar superlattice reflections indicates that the lower temperature phases are described by a superposition of order parameters.

Peripheral T-cell lymphoma in a five year old.

We report a case presenting with persistent pyrexia that led to the diagnosis of peripheral T-cell lymphoma, a rare malignancy in childhood. The case illustrates diagnostic conundrums in a patient who is not responding as expected to treatment.

X-ray ultramicroscopy using integrated sample cells.

The X-ray ultramicroscope (XuM), based on using a scanning electron microscope as host, provides a new approach to X-ray projection microscopy. The right-angle-type integrated sample cells described here expand the capabilities of the XuM technique. The integrated sample cell combines a target, a spacer, a sample chamber, and an exit window in one physical unit, thereby simplifying the instrumentation and providing increased mechanical stability.

Experimental and theoretical study of the surface-controlled dissolution of cylindrical particles. Application to solubilization of potassium hydrogen carbonate in hot dimethylformamide.

In this paper we present a mathematical model for the surface-controlled dissolution of cylindrical solid particles. This is employed to interpret experimental data published previously for the dissolution of potassium bicarbonate in dimethylformamide at elevated temperatures. Significant kinetic differences in assuming cylindrical rather than spherical shapes are reported with the former representing a closer approximation to the true shape of the particles as revealed by scanning electron microscopy.

Correlation between impairment and motor performance during reaching tasks in subjects with spastic hemiparesis.

Objective: The main purposes of this study were to examine, in subjects with chronic hemiparesis following a stroke: (i) the correlations between tests of muscle tone, stiffness, spasticity, paresis and co-contraction, and (ii) the correlations of these tests and measurements of impairment to upper extremity motor performance.

Design: Prospective, cross-sectional, correlation matrix using sample of convenience.

Subjects: Thirteen subjects with chronic hemiparesis secondary to a cerebrovascular accident (stroke) were tested.

On qualitative and quantitative analysis in analyser-based imaging.

Using rigorous wave-optical formalism, a general expression is obtained for the image intensity distribution in combined analyser-based/propagation-based phase-contrast imaging. This expression takes into account partial coherence of the wave incident on the object as well as the finite resolution of the detector system. Using this general expression, two approaches based on the geometrical optics and weak-object approximations are applied to derive simple solutions to the inverse problem of reconstruction of the phase and amplitude of the object wave.