Nanometer flat blazed x-ray gratings using ion beam figure correction.

With the development of nanometer accuracy stitching interferometry, ion beam figuring (IBF) of x-ray mirrors can now be achieved with unprecedented performance. However, the process of producing x-ray diffraction gratings on these surfaces may degrade the figure quality due to process errors introduced during the ruling of the grating grooves. To address this challenge, we have investigated the post-production correction of gratings using IBF, where stitching interferometry is used to provide in-process feedback. A concern with ion beam correction in this case is that ions will induce enough surface mobility of atoms to cause smoothing of the grating structure and degradation of diffraction efficiency. In this study we found however that it is possible to achieve a nanometer-level planarity of the global grating surface with IBF, while preserving the grating structure. The preservation was so good, that we could not detect a change in the diffraction efficiency after ion beam correction. This is of major importance in achieving ultra-high spectral resolution, and the preservation of brightness for coherent x-ray beams.

A new Kirkpatrick-Baez-based scanning microscope for the Submicron Resolution X-ray Spectroscopy (SRX) beamline at NSLS-II.

The development, construction, and first commissioning results of a new scanning microscope installed at the 5-ID Submicron Resolution X-ray Spectroscopy (SRX) beamline at NSLS-II are reported. The developed system utilizes Kirkpatrick-Baez mirrors for X-ray focusing. The instrument is designed to enable spectromicroscopy measurements in 2D and 3D with sub-200 nm spatial resolution. The present paper focuses on the design aspects, optical considerations, and specifics of the sample scanning stage, summarizing some of the initial commissioning results.

A coded aperture microscope for X-ray fluorescence full-field imaging.

The design and construction of an instrument for full-field imaging of the X-ray fluorescence emitted by a fully illuminated sample are presented. The aim is to produce an X-ray microscope with a few micrometers spatial resolution, which does not need to scan the sample. Since the fluorescence from a spatially inhomogeneous sample may contain many fluorescence lines, the optic which will provide the magnification of the emissions must be achromatic, i.e. its optical properties must be energy-independent. The only optics which fulfill this requirement in the X-ray regime are mirrors and pinholes. The throughput of a simple pinhole is very low, so the concept of coded apertures is an attractive extension which improves the throughput by having many pinholes, and retains the achromatic property. Modified uniformly redundant arrays (MURAs) with 10 µm openings and 50% open area have been fabricated using gold in a lithographic technique, fabricated on a 1 µm-thick silicon nitride membrane. The gold is 25 µm thick, offering good contrast up to 20 keV. The silicon nitride is transparent down into the soft X-ray region. MURAs with various orders, from 19 up to 73, as well as their respective negative (a mask where open and closed positions are inversed compared with the original mask), have been made. Having both signs of mask will reduce near-field artifacts and make it possible to correct for any lack of contrast.

Impact of systematic dynamic maneuvers during computed tomography scan on the T classification of head and neck cancers.

OBJECTIVES: To evaluate the impact of systematic dynamic maneuvers during CT scan on the T-staging of head and neck cancer (HNC). MATERIALS AND METHODS: CT scans from the initial workup of 443 consecutive patients treated for HNC in our institution were retrospectively analyzed. CT scans were performed in both expert centers (comprehensive cancer center and university hospital) and non-expert centers. We noted whether dynamic maneuvers (DM) were performed, in 3 categories, namely: DM not done (DMND), done and inadequate (DMDI), done and adequate (DMDA). In the group with DMDA, T-stage was evaluated without and with DM. Interobserver agreement for T staging was assessed after independent double reading of CT scans with and without DM by two radiologists in a random sample. RESULTS: Among the 443 CT scans, DMND was observed in 36.3%, DMDI in 9.3% and DMDA in 54.4%. DMDA were significantly more frequent in expert than in non-expert centers (93.4 vs 6.6%, p < 0.001). In CT scans with DMDA, analysis of the 141 scans rated as T1, T2, T3, or T4 without DM showed agreement of 88.7% with scans with DM, corresponding to a reclassification rate of 11.3% (kappa = 0.85, 95%CI [0.78;0.92]). Among lesions initially classed as Tx without DM (N = 100), the reclassification rate was 76% including DM. CONCLUSION: The performance of systematic DM integrated into CT protocols is useful to reclassify the T stage in HNC and is essential in case of lesions initially classified as Tx without DM. DM should be performed routinely in expert and nonexpert centers.

X-ray phase contrast imaging and noise evaluation using a single phase grating interferometer.

In this paper we present some quantitative measurements of X-ray phase contrast images and noise evaluation obtained with a recent grating based X-ray phase contrast interferometer. This device is built using a single phase grating and a large broadband X-ray source. It was calibrated using a reference sample and finally used to perform measurements of a biological fossil: a mosquito trapped in amber. As phase images, noise was evaluated from the measured interferograms.

Wavefront analysis of nonlinear self-amplified spontaneous-emission free-electron laser harmonics in the single-shot regime.

The single-shot spatial characteristics of the vacuum ultraviolet self-amplified spontaneous emission of a free electron laser (FEL) is measured at different stages of amplification up to saturation with a Hartmann wavefront sensor. We show that the fundamental radiation at 61.5 nm tends towards a single-mode behavior as getting closer to saturation. The measurements are found in good agreement with simulations and theory. A near diffraction limited wavefront was measured. The analysis of Fresnel diffraction through the Hartmann wavefront sensor hole array also provides some further insight for the evaluation of the FEL transverse coherence, of high importance for various applications.

In situ metrology for adaptive x-ray optics with an absolute distance measuring sensor array.

Adaptive x-ray mirrors are emerging as one of the primary solutions for meeting the performance needs of the next generation of x-ray light sources. Currently, these mirrors operate open loop with intermittent feedback from invasive sensors that measure the beam quality. This paper outlines a novel design for real-time in situ metrology of the shape of these mirrors using an array of interferometric sensors that does not interrupt the x-ray beam. We describe a proof-of-principle demonstration which shows sub-nm agreement over a range of mirror deflection magnitudes and shapes as compared to simultaneous measurements by using a large-aperture Fizeau interferometer.

Endarteritis and false aneurysm complicating aortic coarctation.

We report a tricky case of endocarditis because of the localization, aortic coarctation, and the pathogenic bacteria Actinobacillus actinomycetemcomitans. Furthermore, we underline the leading role of transesophageal echocardiography in the diagnosis of aortic endarteritis. First, aortitis was treated with antibiotics and, second, successfully operated on.

Fragmentation of a right atrial myxoma presenting as a pulmonary embolism.

We report here a tricky case of right atrial myxoma with a pulmonary localization mimicking pulmonary thromboembolism. The diagnosis on imaging investigation was delayed because of its atypical appearance. This case report emphasizes the leading role of transthoracic and transesophageal echocardiography in the management of this condition. In autopsy series, the incidence of primary tumors of the heart is evaluated at 0.0017% to 0.19%.(1) Nearly half of them are myxoma.(1, 2) Myxoma are more frequently observed in adults and are commonly localized in the left atrium. Signs and symptoms are comparable to those arising in other cardiovascular and systemic conditions, including variable cardiac murmur, uneasiness, blackout, systemic embolism, cardiac insufficiency, lasting fever, or sudden death.(3) Rare cases of pulmonary embolism have been described. We report here an atypical case of right atrial myxoma with a pulmonary localization mimicking pulmonary embolus.

Collapse and massive pulmonary edema secondary to thrombosis of a mitral mechanical heart valve prosthesis during low-molecular weight heparin therapy.

Mechanical heart valves (MHV) are particularly exposed to thrombosis if anticoagulation becomes ineffective. Thromboembolic complications may be avoided by oral anticoagulation with vitamin K antagonists or derivatives of unfractionated heparin. A few cases of low-molecular weight heparin (LMWH) as sole anticoagulant in patients with MHV have been published, though with contradictory results. We report a case of a massive thrombosis of a St. Jude Medical mitral valve after the patient had been treated for one month with calcium nadroparin (Fraxiparine).

[Value of eptifibatide during salvage angioplasty with coronary stenting after failure of thrombolysis. Report of a series of 41 patients]. / Intérêt de l'eptifibatide au cours de l'angioplastie de sauvetage avec stenting coronaire après échec de thrombolyse. A propos d'une série de 41 patients.

AIM: To evaluate the risks and the significance of the use of an anti-GPIIb/IIIa, in this case Eptifibatide, during angioplasty following presumed failure of thrombolysis in the acute phase of myocardial infarction. METHOD: Patients thrombolyzed following MI < 6 hours. Presumed failure of reperfusion with full dose thrombolysis. Analysis evaluated the success of angioplasty associated with anti-GPIIb/IIIa treatment and the hospital phase outcome. RESULTS: 41 consecutive patients, 32 male (78%) and 9 female (22%), were included. Infarction concerned the anterior region in 22 cases (54%) and inferior in 19 cases (46%). Fibrinolysis was performed using Alteplase in 28 patients (68%) and Reteplase in 13 patients (32%). Radial access was performed in 32 cases (78%). All of the patients received Eptifibatide with a bolus then infusion from their admission to the haemodynamic suite, on average 1 h 30 after the start of thrombolytic treatment. A total of 49 stents were implanted in 41 patients. A flux of TIMI 3 was obtained in 37 patients (90.2%). TIMI 2 in 2 patients (4.9%) and no reflow in 2 patients (4.9%). Four counter-pulsions by intra-aortic balloon were necessary (9.8%) for cardiogenic shock. No decrease in TIMI flux was observed after the angioplasty procedure. The main complications were a death from cardiogenic shock in one patients (2.4%), a non-fatal digestive tract haemorrhage in 2 cases (4.9%) and a single femoral haematoma requiring transfusion. CONCLUSION: The initial results were encouraging: high success rates, rare vascular complications, a probable consequence of the radial approach. The association of an anti-GPIIb/IIIa, Eptifibatide, therefore appears achievable during angioplasty with the positioning of a coronary endoprosthesis following the presumed failure of full dose thrombolysis.

Delayed left atrial wall dissection after mitral valve replacement.

We report two unusual cases of left atrial wall dissection creating a left atrial pseudoaneurysm associated with regurgitation a few months after mitral valve replacement. We emphasize the important role of transesophageal echocardiography in the diagnosis. The two patients successfully underwent surgery.

Direct Angioplasty for Acute Myocardial Infarction in Elderly Patients Using Transradial Approach.

BACKGROUND: In acute myocardial infarction (AMI), immediate outcome seems to be better after direct coronary angioplasty (DCA) than thrombolysis. Right transradial approach (RTRA) has been currently advocated as an alternative catheterization method for coronary angioplasty, but it is an exceptional technique in the treatment of AMI. PURPOSE: The goal of this prospective study was to evaluate feasibility and safety of DCA using the RTRA in elderly patients. METHODS: All patients, 70 years or older with AMI (less than 6 hours after the onset of symptoms), were included in this study. Exclusion criteria were ischemic Allen Test, and previous thrombolytic treatment. Left heart catheterization, with selective coronary angiograms were realized in all of them, using RTRA. RESULTS: Forty six patients, (mean age 76Â+/-5, range 70-85), (31 men, 15 women), were included. Coronary catheterization using RTRA was not possible in 4 patients, (9.1%), and DCA was not necessary in 2 other patients with two distal lesions (4.5%). In the 40 remaining patients, transradial coronary angioplasty of the infarct related vessel could be successfully achieved in 40 patients, (100%) with balloon alone in 21 patients, (52.5%), or stents in 19 patients, (47.5%). Two patients with cardiogenic shock died (in hospital mortality: 4.5%). In 2 patients, recurrent angina needed new angioplasty using the same RTRA (4.5%), and in 2 other patients, asymptomatic postprocedural right radial artery occlusion was observed. Before the 24th hr, 30/40 patients (75%) could stand up with an early discharge, (7Â+/-4 days). CONCLUSION: DCA using RTRA for AMI in elderly patients can be easily realized, with a high rate of success, without any more major local complications than using the usual femoral route, allowing earlier getting up and discharge.

Electromagnetic-field distribution measurements in the soft x-ray range: full characterization of a soft x-ray laser beam.

We report direct measurement of the electromagnetic-field spatial distribution in a neonlike Ar capillary discharge-driven soft x-ray laser beam. The wave front was fully characterized in a single shot using a Shack-Hartmann diffractive optics sensor. The wave front was observed to be dependent on the discharge pressure and capillary length, as a result of beam refraction variations in the capillary plasma. The results predict approximately 70% of the laser beam energy can be focused into an area 4 times the size of the diffraction-limited spot, reaching intensities of approximately 4 x 10(13) W/cm(2).

Numerical and experimental study of grating efficiency for synchrotron monochromators.

The development of third-generation synchrotron sources has stimulated efforts toward high-resolution monochromators. A good knowledge of grating efficiency is needed to achieve an optimal compromise between resolution and photon flux. Because simple geometric models fail to describe correctly the gratings properties in the UVtosoft-X-ray range, we have developed a simulation software based on differential theory. A simplified R-matrix propagation algorithm assures the numerical stability of the code for deep gratings. Our numerical results are compared with previous research on deep gratings. Experimental and numerical studies have been performed on some test cases at a synchrotron source. Very good agreement between numerical prediction and measurement has been found.