By exciting a series of 1s^{2} ^{1}S_{0}→1snp^{1}P_{1} transitions in heliumlike nitrogen ions with linearly polarized monochromatic soft x rays at the Elettra facility, we found a change in the angular distribution of the fluorescence sensitive to the principal quantum number n. In particular it is observed that the ratio of emission in directions parallel and perpendicular to the polarization of incident radiation increases with higher n. We find this n dependence to be a manifestation of the Hanle effect, which served as a practical tool for lifetime determinations of optical transitions since its discovery in 1924. In contrast to traditional Hanle effect experiments, in which one varies the magnetic field and considers a particular excited state, we demonstrate a "soft x-ray Hanle effect" which arises in a static magnetic field but for a series of excited states. By comparing experimental data with theoretical predictions, we were able to determine lifetimes ranging from hundreds of femtoseconds to tens of picoseconds of the 1snp^{1}P_{1} levels, which find excellent agreement with atomic-structure calculations. We argue that dedicated soft x-ray measurements could yield lifetime data that are beyond current experimental reach and cannot yet be predicted with sufficient accuracy.
The majority of today's electro-photographic toners incorporate an external additive(s) to fine tune their desired performance attributes. One of the key additives found to be effective at influencing powder flow, charging behavior, and charge stability of conventionally milled or chemically produced toners is fumed silica and more so if the silica has been rendered hydrophobic.Fumed silica is produced via a pyrogenic process and results in primary particles coalescing, fusing and sintering to form particles with an aggregated structure. This secondary particle has a size ranging from approximately 100 – 200 nm depending on the process conditions for the specific silica grade. These aggregates form hydrogen bonds via the silanol groups and also become mechanically intertwined forming a tertiary structure called agglomerates. The size of these agglomerates can span from several microns to several hundred microns. Due to the much larger size and irregularities associated with an agglomerated particle, more aggressive shear conditions would be required to distribute the silica more uniformly on the toner surface. Such conditions could lead to silica becoming embedded and affect the toner itself. In the end, the structure and size of the agglomerate results in particle dispersibility unto the toner being compromised. Poor dispersibility of the external additive can lead to non-uniform behavior with respect to the toner's flow, charge and stability leading to sub-standard print performance and longevity.In an earlier paper we presented a study comparing structure modified de-agglomerated fumed silica to that of traditional fumed silica. The conclusion then was that de-agglomerated silica dispersed more efficiently and thereby led to improvements in toner flow, charging characteristics and charge stability. In this study, the work is a continuation and extension of the effects structure modification has on performance.
The case was a man in his 60s. With a complaint of loss of appetite, a peripheral type 3 lesion was found from the lower body of the stomach to the vestibule, and a biopsy revealed poorly differentiated adenocarcinoma. CT examination revealed that the tumor had invaded the left lobe of the liver and the transverse colon, and that the para-aortic lymph nodes were swollen and multiple nodules of the gastrocolonic mesentery were found. After 6 courses of S-1 plus cisplatin(SP)therapy were performed, the tumor shrank and lymph node swelling and nodule disappearance were observed. Laparotomy and pyloric gastrectomy, partial liver resection, D2 dissection, and Roux-en-Y reconstruction were performed. As a result of histopathological examination, R0 was resected. After the operation, S-1 was taken orally for 1 year, and no recurrence or metastasis has been observed 6 and a half years after the operation. This time, we report a valuable case in which SP therapy was successful for unresectable gastric cancer and long-term survival was obtained by conversion surgery.
A woman in her 80s was diagnosed with an abdominal mass during physical examination. Contrast-enhanced computed tomography(CT)revealed a tumor with contrast enhancement outside the ileocecal region of the intestine, and the ileocolic artery penetrated the tumor. No tumor was detected by colonoscopy. An endoscope could not be passed through due to an ileocecal valve stenosis. A biopsy of the ileocecal valve revealed only lymphocyte hyperplasia without adenocarcinoma components. Barium enema examination demonstrated no influx of the contrast medium from the cecum into the oral side of the intestine. Since a gastrointestinal stromal tumor in the ileocecal region was suspected, laparotomy was performed in the ileocecal region owing to the preoperative diagnosis of suspected malignant lymphoma, revealing a 5-cm elastic hard tumor outside the ileocecal wall. The tumor could not be separated from the intestinal tract. Histopathological examination revealed no lesion on the mucosal surface, although poorly differentiated adenocarcinoma infiltrated from the submucosa to the serosa. Thus, the patient was diagnosed with extramural growth-type ileocecal colon cancer. This disease is relatively rare but need to be kept in mind.
A man in his 50s had undergone steroid therapy for eosinophilic granulomatosis with polyangiitis(EGPA). Since an examination for malignant tumors revealed type 0-Ⅰsp(cT1aN0M0)and type 2(cT2N0M0)lesions in the proximal and mid- transverse colon, respectively, he was referred to our department. Endoscopic resection was performed on the proximal lesion. After the confirmation of curative resection, laparoscopic partial colectomy(transverse colon)and D3 lymph node dissection were performed on the mid-transverse lesion. Because of the patient's favorable postoperative course, he was discharged from the hospital on POD17. Since steroids and immunosuppressants may cause immunological abnormalities and malignant tumors, such patients should be strictly followed up.
The existence of the axion is a unique solution for the strong CP problem, and the axion is one of the most promising candidates of the dark matter. Investigating Solar Axion by Iron-57 (ISAI) is being prepared as a complemented table-top experiment to confirm the solar axion scenario. Probing an X-ray emission from the nuclear transitions associated with the axion-nucleon coupling is a leading approach. ISAI searches for the monochromatic 14.4 keV X-ray from the first excited state of ^{57} 57 Fe using a state-of-the-art pixelized silicon detector, dubbed XRPIX, under an extremely low-background environment. We highlight scientific objectives, experimental design and the latest status of ISAI.
Abstract Recent high-resolution X-ray spectroscopy revealed the possible presence of charge exchange (CX) X-ray emission in supernova remnants (SNRs). Although CX is expected to take place at the outermost edges of SNR shells, no significant measurement has been reported so far due to the lack of nearby SNR samples. Here we present an X-ray study of SNR G296.1−0.5, which has a complicated multiple-shell structure, with the Reflection Grating Spectrometer on board XMM-Newton. We select two shells in different regions and find that in both regions the O vii line shows a high forbidden-to-resonance ( f / r ) ratio that cannot be reproduced by a simple thermal model. Our spectral analysis suggests a presence of CX and the result is also supported by our new radio observation, where we discover evidence of molecular clouds associated with these shells. Assuming G296.1−0.5 has a spherical shock, we estimate that CX is dominant in a thin layer with a thickness of 0.2%–0.3% of the shock radius. The result is consistent with a previous theoretical expectation and we therefore conclude that CX occurs in G296.1−0.5.
A 51-year-old woman underwent a CT scan performed that revealed a neoplastic lesion in the upper abdomen, and she was referred to our surgical department. Abdominal CT showed a tumor of about 50 mm lying between the posterior wall of the gastric minor curvature and the pancreas. Continuity with the surrounding tissue was not clear. Ultrasonography showed that the tumor was mobile on postural change, and it was considered to originate from the mesentery. In addition, PET scanning showed mild accumulation, and MRI showed limited diffusion, suggesting the possibility of malignancy. Laparoscopic tumor resection was performed as a diagnostic treatment. Intraoperative findings showed tumor continuity only with the lesser omentum, and the patient was judged to have a primary tumor of the lesser omentum. Histopathological findings showed proliferation of myofibroblasts and lymphocyte infiltration, and the patient was thus diagnosed as having an inflammatory myofibroblastic tumor. Inflammatory myofibroblastic tumor as a primary tumor of the lesser omentum is rare and is reported here along with a literature review.
