Differential interference contrast microscopy for cells using hard x-ray holography.

We propose a differential interference contrast method for cells using hard x-ray Gabor holography and knife-edge filtering in the spatial frequency domain, without relying on beam shearing. A phase object is holographically recorded and reconstructed by computer. Interference between the wavefronts of zeroth order weighted by ejπ/2 in the positive frequency region produces a dark image. Similarly, interference between the wavefronts of the zeroth order weighted by ej3π/2 in the negative frequency region produces a bright image. By adding these two intensity distributions, good quality phase-contrast images of 8-µm-diameter polystyrene beads and human HeLa cells were obtained.

Kinetic modeling of particle dynamics in H(-) negative ion sources (invited).

Progress in the kinetic modeling of particle dynamics in H(-) negative ion source plasmas and their comparisons with experiments are reviewed, and discussed with some new results. Main focus is placed on the following two topics, which are important for the research and development of large negative ion sources and high power H(-) ion beams: (i) Effects of non-equilibrium features of EEDF (electron energy distribution function) on H(-) production, and (ii) extraction physics of H(-) ions and beam optics.

Numerical study of the inductive plasma coupling to ramp up the plasma density for the Linac4 H(-) ion source.

In the Linac4 H(-) ion source, the plasma is generated by an RF antenna operated at 2 MHz. In order to investigate the conditions necessary for ramping up the plasma density of the Linac4 H(-) ion source in the low plasma density, a numerical study has been performed for a wide range of parameter space of RF coil current and initial pressure from H2 gas injection. We have employed an Electromagnetic Particle in Cell model, in which the collision processes have been calculated by a Monte Carlo method. The results have shown that the range of initial gas pressure from 2 to 3 Pa is suitable for ramping up plasma density via inductive coupling.

Plasma ignition and steady state simulations of the Linac4 H(-) ion source.

The RF heating of the plasma in the Linac4 H(-) ion source has been simulated using a particle-in-cell Monte Carlo collision method. This model is applied to investigate the plasma formation starting from an initial low electron density of 10(12) m(-3) and its stabilization at 10(18) m(-3). The plasma discharge at low electron density is driven by the capacitive coupling with the electric field generated by the antenna, and as the electron density increases the capacitive electric field is shielded by the plasma and induction drives the plasma heating process. Plasma properties such as e(-)/ion densities and energies, sheath formation, and shielding effect are presented and provide insight to the plasma properties of the hydrogen plasma.

Equivalent circuit of radio frequency-plasma with the transformer model.

LINAC4 H(-) source is radio frequency (RF) driven type source. In the RF system, it is required to match the load impedance, which includes H(-) source, to that of final amplifier. We model RF plasma inside the H(-) source as circuit elements using transformer model so that characteristics of the load impedance become calculable. It has been shown that the modeling based on the transformer model works well to predict the resistance and inductance of the plasma.

Modeling of neutrals in the Linac4 H(-) ion source plasma: hydrogen atom production density profile and Hα intensity by collisional radiative model.

To control the H(0) atom production profile in the H(-) ion sources is one of the important issues for the efficient and uniform surface H(-) production. The purpose of this study is to construct a collisional radiative (CR) model to calculate the effective production rate of H(0) atoms from H2 molecules in the model geometry of the radio-frequency (RF) H(-) ion source for Linac4 accelerator. In order to validate the CR model by comparison with the experimental results from the optical emission spectroscopy, it is also necessary for the model to calculate Balmer photon emission rate in the source. As a basic test of the model, the time evolutions of H(0) production and the Balmer Hα photon emission rate are calculated for given electron energy distribution functions in the Linac4 RF H(-) ion source. Reasonable test results are obtained and basis for the detailed comparisons with experimental results have been established.

Analysis of rapid increase in the plasma density during the ramp-up phase in a radio frequency negative ion source by large-scale particle simulation.

Numerical simulations become useful for the developing RF-ICP (Radio Frequency Inductively Coupled Plasma) negative ion sources. We are developing and parallelizing a two-dimensional three velocity electromagnetic Particle-In-Cell code. The result shows rapid increase in the electron density during the density ramp-up phase. A radial electric field due to the space charge is produced with increase in the electron density and the electron transport in the radial direction is suppressed. As a result, electrons stay for a long period in the region where the inductive electric field is strong, and this leads efficient electron acceleration and a rapid increasing of the electron density.

Optimal depth of insertion of left-sided double-lumen endobronchial tubes cannot be predicted from body height in below average-sized adult patients.

BACKGROUND AND OBJECTIVE: The optimal depth of insertion of left-sided double-lumen endobronchial tubes is strongly correlated with body height in average-sized adults. However, this relationship has not been studied in below average-sized adult patients. We investigated whether or not there is a clinically useful relationship in below average-sized adult patients. METHODS: One hundred and ninety six consecutive adult patients undergoing thoracic surgery under one-lung anaesthesia (body height < or = 155 cm) were included in this study. Left-sided double-lumen tubes were inserted under the guidance of a fibre-optic bronchoscope. Optimal depth was defined as the proximal surface of the bronchial cuff positioned just below the carina. RESULTS: There was a statistically significant positive correlation between body height and the optimal depth of insertion (r = 0.61, P < 0.0001); however, the correlation coefficient was low. The actual optimal depth of insertion of one patient was even 4.5 cm shorter than that obtained from the equation. CONCLUSION: Although there was a statistically significant correlation between body height and the optimal depth of insertion of left sided double lumen tubes in adult patients of short stature (< or = 155 cm), clinical application of the equation is not warranted and these tubes should be inserted under direct vision with a fibre-optic bronchoscope.

Tophaceous gout in the bipartite patella with intra-osseous and intra-articular lesions: a case report.

We report a case of a 34-year-old man who had an acute gouty attack with tophi around the accessory bone of the bipartite patella with intra-osseous lesions. As the symptoms did not respond to conservative treatments, the patient was treated surgically. Arthroscopy revealed urate crystals surrounded by inflammatory synovitis on the surface of the bipartite patella. Arthrotomy exposed the abundant crystals around the accessory bone and in the intra-osseous lesion. These findings made us speculate that some pre-existing inflammatory conditions around the accessory bone induced deposition of urate crystals, and the destruction of the barrier between the deposits and the joint led to an acute arthritis. Curettage of the tophi resulted in immediate improvement of knee function. There had been no recurrence of symptoms at the 2-year follow-up.

Mass spectrometric investigation of gaseous YbH, YbO and YbOH molecules.

The high-temperature gaseous molecules YbH, YbO and YbOH have been identified and their thermochemistry investigated by the Knudsen effusion mass spectrometry technique coupled with a controlled pressure gas inlet system. Solid ytterbium monosilicide and disilicide samples were made to react in the Knudsen cell with H2(g) and H2(g)/O2(g); in these conditions, several gaseous species (Yb, YbO, YbH, YbOH, SiO, SiO2, H2O) were formed under equilibrium conditions. The temperature dependences of the partial pressures of the observed gaseous molecules were analyzed to derive the Yb--X bond energies (X = H, O, OH). Selected values are D0o(Yb--H) = 179.4 +/- 2.0 kJ mol(-1), D0o(Yb--O) = 384 +/- 10 mol(-1) and D0o(Yb--OH) = 322 +/- 12 kJ mol(-1), and Delta(at)H0o(YbOH) = 746 +/- 12 kJ mol(-1). Density functional theory (DFT) calculations were also performed. Experimental and computational results are discussed and compared to previous data when available. The SiO/SiO2 high-temperature gaseous equilibrium was also observed.

Skin blood flow and plasma catecholamine concentrations during removal of a phaeochromocytoma in a child.

A 9-yr-old boy with an adrenal phaeochromocytoma underwent removal of the tumour under general anaesthesia using sevoflurane and nitrous oxide combined with thoracic epidural anaesthesia. Skin blood flow in the first toe, as measured by laser Doppler flowmetry, markedly decreased during manipulation of the tumour and increased after removal of it. Skin blood flow correlated more significantly with plasma catecholamine concentrations than did mean arterial blood pressure. Skin blood flow may be used as a non-invasive measure of plasma catecholamine concentrations during removal of a phaeochromocytoma in paediatric patients.

Use of epidural anaesthesia for surgery in a patient with Kennedy's disease.

Use of neuraxial block in a patient with motor neuron disease is controversial. We describe the anaesthetic management by epidural anaesthesia of a patient with Kennedy's disease, a rare lower motor neuron disease characterized by progressive weakness and wasting of limbs and bulbar muscles. The perioperative course was uneventful, and there was no exacerbation of neurologic signs or symptoms. We suggest that a patient with Kennedy's disease may be successfully managed by epidural anaesthesia for surgical internal urethrotomy.

Reconstruction of the medial patellofemoral ligament for the treatment of habitual or recurrent dislocation of the patella in children.

We investigated the clinical outcome of a reconstructive procedure of the medial patellofemoral ligament for the treatment of habitual or recurrent dislocation of the patella in four children (6 knees), with a minimum follow-up of four years. The technique involves transfer of the tendon of semitendinosus to the patella using the posterior one-third of the femoral insertion of the medial collateral ligament as a pulley. There was no recurrence of dislocation after surgery. The mean Kujala score at follow-up was 96.3 points. Radiological assessment showed that the congruence angle, the tilt angle and the lateral shift radio were restored to normal. The lateral and medial stress shift ratios and the Insall-Salvati ratio remained abnormal. We conclude that this technique can be recommended for the treatment of habitual or recurrent patellar dislocation in children, although hypermobility and patella alta are not fully corrected.

MR imaging of benign and malignant lesions in the buccal space.

OBJECTIVES: To evaluate MRI characteristics of buccal space lesions and to discuss the sensitivity of MRI in predicting malignancy of those lesions. METHODS: Thirty patients with malignant (n=7) or benign (n=23) lesions originating in the buccal space were reviewed retrospectively. MR images were assessed for the margins, internal architecture, signal intensity of lesions and their relation to the surrounding structures. RESULTS: Two cases of soft tissue sarcoma were shown as ill-defined masses with infiltration into adjacent muscles and bone. On the other hand, all tumors of minor salivary gland origin, whether malignant (n=4) or benign (n=2), were well-defined and confined within the buccal fat pad without infiltration into surrounding structures. All haemangiomas (n=9) had very high T2-weighted signal intensity. Three out of them contained signal voids on all sequences thought to represent phleboliths, a finding strongly suggestive of the diagnosis. Inflammatory lesions were characterized by the presence of edema in the surrounding fat. When ill-defined margins, infiltration into muscles and bone destruction were used as the criteria for the malignancy, only two out of seven malignant tumors were correctly diagnosed (sensitivity 29%). CONCLUSIONS: Although MR imaging was useful in demonstrating the extent of buccal space lesions, its diagnostic value in predicting malignancy was very limited. It was especially true for malignant tumors of minor salivary gland origin, which were typically seen as well-defined masses without infiltration into surrounding structures on MRI.

MR detection of iliac bone marrow involvement by malignant lymphoma with various MR sequences including diffusion-weighted echo-planar imaging.

OBJECTIVE: To assess the diagnostic accuracy of MR imaging for detecting bone marrow infiltration by malignant lymphoma. PATIENTS AND DESIGN: Fifty-three patients with malignant lymphoma underwent MR imaging and bone marrow biopsy. In 80 iliac crests of the 53 patients (13 positive specimens in 9 patients and 67 negative specimens in 44 patients), biopsy results and the signal intensity characteristics were compared. MR sequences included T1-weighted SE, T2-weighted FSE with fat suppression, FSE STIR, and diffusion-weighted EPI with fat suppression at 1.5 T. RESULTS AND CONCLUSIONS: To detect lymphoma infiltration, T1-weighted SE had the highest sensitivity (92%) and diffusion-weighted EPI with fat suppression and FSE STIR had the highest specificity (92.5% and 92%, respectively). A combination of T1-weighted SE and FSE STIR yielded the highest sensitivity and specificity (85% and 97%, respectively). A combination of T1-weighted SE and FSE STIR sequences seems to be the current choice of imaging protocol for detecting bone marrow infiltration by malignant lymphoma.

Zernike-type X-ray imaging microscopy at 25 keV with Fresnel zone plate optics.

A Zernike-type imaging microscope using a sputtered-sliced Fresnel zone plate (SS-FZP) has been developed and tested at an X-ray energy of 25 keV. The SS-FZP was used as an objective. A copper (Cu) phase plate was placed at the back focal plane of the SS-FZP in order to produce phase contrast. The performance of the Zernike-type imaging microscope was tested with a gold (Au) mesh and a resolution test pattern at undulator beamline 47 of SPring-8. The Au mesh and the resolution test pattern could be imaged in transmission with a magnification of x10.2. Owing to the Cu phase plate, different image contrast was observed compared with the bright-field image contrast. Tantalum microstructures down to 0.5 microm line-and-space have been observed on spatial resolution test patterns.

Development of a multilayer Fresnel zone plate for high-energy synchrotron radiation X-rays by DC sputtering deposition.

Hard X-ray microscopy with high spatial resolution (or=20 keV) because a large thickness (aspect ratio) can be available. Various types of multilayer FZPs have been fabricated by DC sputtering deposition. Their focusing characteristics have been evaluated at the high-brilliance undulator beamline BL47XU of SPring-8. An optical system using a Cu/Al multilayer FZP (with an outermost zone width of 0.25 microm) as the focusing optics fabricated by the optimum deposition condition with precise film (zone) thickness control has attained an almost diffraction-limited microbeam of 0.3-0.35 microm at 8.9 keV. A line-and-space resolution test pattern has been observed: fine structures up to 0.2 microm were clearly observed in the measured image. This FZP has been working since 1995, keeping good focusing characteristics. It can be said from these results that a spatial resolution better than 0.1 microm in the high-energy X-ray region is in prospect by the development of a multilayer FZP with a narrower outermost zone width in the near future.

Hard X-ray microbeam experiments with a sputtered-sliced Fresnel zone plate and its applications.

Hard X-ray microbeam experiments with sputtered-sliced Fresnel zone plates have been performed. Zone plates with an outermost zone width of 0.25 microm (#FZP1) and 0.1 microm (#FZP2) were fabricated and evaluated. In a scanning X-ray microscopy experiment, a line-and-space pattern with structure as fine as 0.1 microm was resolved using #FZP2 at an X-ray wavelength of 1 A. As an application of the microbeam technique, a two-dimensional distribution of constituent elements in forensic samples has been obtained (e.g. section view of human and elephant hairs) using fluorescent scanning microscopy.

Sonographic appearances of malignant lymphoma of the salivary glands.

PURPOSE: We undertook this retrospective study to describe the sonographic findings in patients with malignant lymphoma of the major salivary glands. METHODS: We reviewed the sonograms and medical records of 7 patients with histologically proven lymphoma of the parotid (3 patients) or submandibular glands (4 patients). RESULTS: Primary lymphoma was found in 1 parotid gland and 2 submandibular glands. The remaining 4 cases were secondary lymphomas. One patient had been diagnosed with Sjögren's syndrome and had been followed up with sonography. In parotid glands, both parenchymal and intraparotid nodal lymphomas were found. All submandibular gland tumors were parenchymal. Intraparotid nodal involvement appeared as multiple small nodules with relatively smooth margins, whereas the parenchymal parotid and submandibular gland lymphomas were larger (25 to 45 mm in longitudinal diameter) and showed various degrees of margin irregularity. All tumors were hypoechoic relative to the normal parenchyma. The primary parotid lymphoma and intraparotid nodal lymphomas had a homogeneous echotexture; the secondary parotid lymphomas and submandibular gland lymphomas were heterogeneous. One submandibular gland lymphoma showed intratumoral echogenic stripes. Neither calcification nor cystic degeneration was observed within the lesions. CONCLUSIONS: Lymphomas of the salivary glands present a variety of sonographic appearances, ranging from multiple small, hypoechoic nodules to an irregularly shaped heterogeneous mass without cystic areas or calcifications.