438 research outputs found
Embedding a set of rational points in lower dimensions
AbstractLet Xn be a set of rational points lying on an n-dimensional flat in a Euclidean space. We prove that for n ⩾ 2, Xn is congruent to a set of rational points in R2n+1, and that for n ⩾ 3, Xn is similar to a set of rational points in R2n-1
Reversing a polyhedral surface by origami-deformation
AbstractWe introduce a new variety of flexatube, a rhombotube. It is obtained from a cardboard rhombohedron consisting of six rhombi with interior angles 60∘ and 120∘, by removing a pair of opposite faces, and then subdividing the remaining four faces by pairs of diagonals. It is reversible, that is, it can be turned inside out by a series of folds, using edges and diagonals of the rhombi. To turn a rhombotube inside out is quite a challenging puzzle. We also consider the reversibility of general polyhedral surfaces. We show that if an orientable polyhedral surface with boundary is reversible, then its genus is 0, and for every interior vertex, the sum of face angles at the vertex is at least 2π. After defining the tube-attachment operation, we show that every polyhedral surface obtained from a rectangular tube by applying tube-attachment operations one after another, can be subdivided so that it becomes reversible
Inactivation of Vibrio vulnificus hemolysin through mutation of the N- or C-terminus of the lectin-like domain
Vibrio vulnificus is an etiological agent causing serious systemic infections in the immunocompromised humans or cultured eels. This species commonly produces a hemolytic toxin consisting of the cytolysin domain and the lectin-like domain. For hemolysis, the lectin-like domain specifically binds to cholesterol in the erythrocyte membrane, and to form a hollow oligomer, the toxin is subsequently assembled on the membrane. The cytolysin domain is essential for the process to form the oligomer. Three-dimensional structure model revealed that two domains connected linearly and the C-terminus was located near to the joint of the domains. Insertion of amino acid residues between two domains was found to cause inactivation of the toxin. In the C-terminus, deletion, substitution or addition of an amino acid residue also elicited reduction of the activity. However, the cholesterol-binding ability was not affected by the mutations. These results suggest that mutation of the C- or N-terminus of the lectin-like domain may result in blockage of the toxin assembly
Tissue-specific expression of histone H3 variants diversified after species separation
Additional file 3: Predicted CDS of human histone H3/H4 variants, contains Table S2, which lists the CDS locus information of the predicted human histone H3 and H4 variants in an Excel file
Rad51 Expression Is a Useful Predictive Factor for the Efficacy of Neoadjuvant Chemoradiotherapy in Squamous Cell Carcinoma of the Esophagus
BACKGROUND: Neoadjuvant chemoradiotherapy (NACRT) for esophageal squamous cell carcinoma (ESCC) is beneficial in the setting of a complete pathological response. Rad51 expression affects both chemo- and radiosensitivity in many cancers; however, its role in ESCC is unclear. METHODS: Rad51 expression was investigated by immunohistochemical staining with resected specimens in 89 ESCC patients who underwent surgery without preoperative therapy. The association with Rad51 and clinicopathological factors was assessed. The expression of Rad51 was also investigated in pretreatment biopsy specimens in 39 ESCC patients who underwent surgery after NACRT and compared with the pathological response to NACRT. RESULTS: Lymph node metastasis was more frequently observed in Rad51-positive cases than negative cases (58.5 vs. 30.6 %, P = 0.0168) in patients treated with surgery alone. Disease-specific survival was decreased in Rad51-positive cases compared to Rad51-negative cases (5 year survival: 79.6 vs. 59.3 %, P = 0.0324). In NACRT patients, completed pathological responses were more frequently observed in Rad51-negative cases than in Rad51-positive cases (68.8 vs. 46.5 %, P = 0.0171). CONCLUSIONS: Rad51 expression in ESCC was associated with lymph node metastasis and poor survival. Additionally, Rad51 expression in pretreatment biopsy specimens was a predictive factor for the response to NACRT. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1245/s10434-013-3220-2) contains supplementary material, which is available to authorized users
Laparoscopic Gastrectomy for Gastric Cancer with Peritoneal Dissemination after Induction Chemotherapy
Gastric cancer with peritoneal dissemination may be diagnosed as unresectable. More recently, as a result of progress in chemotherapy, some patients with peritoneal dissemination have exhibited extended survival. We report on our experience with three patients in whom induction chemotherapy allowed for totally laparoscopic total gastrectomy (TLTG). All three patients were diagnosed as having advanced gastric cancer with peritoneal dissemination using staging laparoscopy. As induction chemotherapy, S-1 combined with cisplatin was administered to two patients and trastuzumab plus capecitabine combined with cisplatin to one patient. TLTG was performed in all patients and there were no postoperative complications. Adjuvant chemotherapy was initiated within 3 weeks after surgery in all three patients. Laparoscopic gastrectomy undertaken after induction chemotherapy was found to be effective and safe; this treatment has the potential to achieve good treatment outcomes in patients with stage IV gastric cancer
Discovery of Negative Superhumps during a Superoutburst of January 2011 in ER Ursae Majoris
We report on a discovery of "negative" superhumps during the 2011 January
superoutburst of ER UMa. During the superoutburst which started on 2011 January
16, we detected negative superhumps having a period of 0.062242(9) d, shorter
than the orbital period by 2.2%. No evidence of positive superhumps was
detected during this observation. This finding indicates that the disk
exhibited retrograde precession during this superoutburst, contrary to all
other known cases of superoutbursts. The duration of this superoutburst was
shorter than those of ordinary superoutbursts and the intervals of normal
outbursts were longer than ordinary ones. We suggest a possibility that such
unusual outburst properties are likely a result of the disk tilt, which is
supposed to be a cause of negative superhumps: the tilted disk could prevent
the disk from being filled with materials in the outmost region which is
supposed to be responsible for long-duration superoutbursts in ER UMa-type
dwarf novae. The discovery signifies the importance of the classical prograde
precession in sustaining long-duration superoutbursts. Furthermore, the
presence of pronounced negative superhumps in this system with a high
mass-transfer rate favors the hypothesis that hydrodynamical lift is the cause
of the disk tilt.Comment: 8 pages, 3 figures, Accepted for publication in PASJ Lette
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