Skyrmions are nanoscale spin textures that are viewed as promising candidates as information carriers in future spintronic devices. Skyrmions have been observed using neutron scattering and microscopy techniques. Real-space imaging using electrons is a straightforward way to interpret spin configurations by detecting the phase shifts due to electromagnetic fields. Here, we report the first observation by electron holography of the magnetic flux and the three-dimensional spin configuration of a skyrmion lattice in Fe(0.5)Co(0.5)Si thin samples. The magnetic flux inside and outside a skyrmion was directly visualized and the handedness of the magnetic flux flow was found to be dependent on the direction of the applied magnetic field. The electron phase shifts φ in the helical and skyrmion phases were determined using samples with a stepped thickness t (from 55 nm to 510 nm), revealing a linear relationship (φ = 0.00173 t). The phase measurements were used to estimate the three-dimensional structures of both the helical and skyrmion phases, demonstrating that electron holography is a useful tool for studying complex magnetic structures and for three-dimensional, real-space mapping of magnetic fields.

This study was performed to determine if there is a relationship between apparent diffusion coefficient (ADC) and cellularity of bone marrow of the posterior ilium. Four groups of various marrow cellularity underwent diffusionweighted echo-planar imaging: 1) adults with normal hypocellularity (21 patients); 2) adults with normal normocellularity (13 patients); 3) young children with normal hypercellularity (5 patients); and 4) adults with lymphomarelated hypercellularity (3 patients). In all adults, marrow cellularity was confirmed by uni-or bilateral bone marrow biopsies. In children, the iliac marrow was presumed hy- Index terms: MRI; bone marrow; diffusion-weighted EPI; marrow cellularity; ADC DIFFUSION-WEIGHTED MRI is a relatively new method to quantitatively image intravoxel incoherent motion (IVIM) in vivo, as introduced by Le Bihan et al (1). These motions include molecular diffusion of water and microcirculation of blood in the capillary network, perfusion (2). By means of a parameter termed apparent diffusion coefficient (ADC), quantification of IVIM is possible. The ADC calculation is based on the signal intensity of the original diffusion-weighted images with two different b factors. Diffusion-weighted MR imaging was recently introduced to evaluate vertebral bone marrow (3-5). Bauer et al (3) reported that pathologic compression fractures are of high signal intensity, whereas benign compression fractures are relatively hypointense. They speculated a decrease in the ADC, hypothesizing that hypercellularity by tumor cells reduced the extracellular space and mobility of water protons, resulting in increased signal intensity on diffusion-weighted images (3). Castillo et al (4) examined various vertebral metastases and found both low and high signal intensity in affected bone marrow on diffusion-weighted images with the same b-value, 165 seconds/mm 2 . They implied that in cases in which lesions are hypointense, the ADC remains normal despite tumor-related hypercellularity within a vertebra, leading to loss of signal on diffusion-weighted images.To our knowledge, Ward et al reported ADC of normal bone marrow for the first time, with a mean value of 0.15 ϫ 10 Ϫ3 mm 2 /second (5). Although it has been suggested that hypercellularity leads to a decrease or no change in ADC of bone marrow, this has not yet been verified. In this study, we sought to determine if there is a relation between ADC and cellularity of bone marrow, using in vivo data of various cellularity groups with histological confirmation. MATERIALS AND METHODS Patients and SubjectsThe study included four groups according to bone marrow cellularity: 1) adults with normal hypocellular marrow (21 patients, 15 men, 6 women; age range, 28 -86 years; mean age, 61.2 years); 2) adults with normal normocellular marrow (13 patients, 6 men, 7 women; age range, 43-78 years; mean age, 62.5 years); 3) young children with normal hypercellular marrow (5 patients, 3 boys, 2 girls; age range, 0 -3 years; mean age, 1.6 years); and 4) adults with lymphoma cell-pack...

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Using a PCR-based cloning technique, we isolated a series of protein tyrosine kinases (PTKs) expressed in a cell line of esophageal squamous cell carcinoma. Sequence analysis revealed 10 different kinds of PTKs of the receptor type [epidermal cell growth factor receptor, insulin-like growth factor I receptor, fibroblast growth factor receptor 4, eck, erk, discoidin domain receptor (DDR)/trk/Ecell adhesion kinase (Cak), HEK2, HEK8, axl and sky] and one PTK of the nonreceptor type (tyk2). Subsequently, we examined the expression of the transcripts of these 11 genes in paired samples of normal and carcinomatous esophageal tissues obtained from 12 cases of esophageal cancer. We found that all 11 gene transcripts were expressed in both carcinomatous and normal tissues, and 6 of them were significantly overexpressed in carcinomatous tissues relative to adjacent normal tissues. Among these, the magnitude of mRNA expression of DDR/trkE/Cak PTK was positively correlated with the proliferative activity of carcinoma cells, but not with their degree of differentiation. Immunohistochemically, DDR was expressed in both normal and cancerous esophageal cells. The intensity of the expression was higher in cancer than normal tissue. In addition, we confirmed the expression of two isoforms of DDR/trkE/Cak in normal and cancerous esophagus. Our study suggests that DDR/trkE/Cak plays an important role in the regulation of proliferation of esophageal cancer.

Centrilobular fibrosis, bridging fibrosis and organizing pneumonia, in addition to bronchiolitis, granulomas and giant cells, are characteristic features of chronic HP with a UIP-like pattern. These features are therefore important in differentiating chronic HP from IPF/UIP, as management strategies differ for the two disorders.