Direct Calculation of Thermodynamic Quantities for Heisenberg Model

The XXX Heisenberg model is studied at finite temperature. The free energy is derived without recourse to Thermal Bethe Ansatz method and Quantum Transfer Matrix method. The result perfectly agrees with the free energy derived by Thermal Bethe Ansatz method. An explicit expression of the cluster expansion coefficient in arbitrary order is presented for the first time.Comment: 26 page

A case of generalized lymphatic anomaly causing skull-base leakage and bacterial meningitis

Generalized lymphatic anomaly (GLA) is a multifocal lymphatic malformation that affects the skin, thoracic viscera, and bones. A 7-year-old boy presented with fever and disturbance of consciousness, and bacterial meningitis was diagnosed. Computed tomography and magnetic resonance imaging revealed middle skull-base leakage due to lymphatic malformation. Past history included facial palsy due to cystic tumors in the right petrous bone 4 years before onset of meningitis. At that time, pericardial effusion had been found and GLA had been diagnosed by pericardial biopsy. He achieved complete recovery under intensive care with antibiotics and mechanical ventilation. At the 3-year follow-up, the patient was healthy with no recurrence of meningitis. We should consider GLA among the differential diagnoses for osteolytic diseases in the pediatric population

A case of acute acalculous cholecystitis complicated by primary Epstein-Barr virus infection

Acute acalculous cholecystitis (AAC) is a rare complication of infectious mononucleosis (IM). An immunocompetent 6-year-old Japanese girl complained of epigastralgia during the course of IM. Ultrasonography (US) revealed a markedly thickened and sonolucent gallbladder wall. No gallstones were apparent. Antibodies against Epstein-Barr virus (EBV) confirmed primary EBV infection. Cytomegalovirus immunoglobulin M showed a false-positive result in the acute phase, probably due to cross-reaction to EBV nuclear antigen. We diagnosed her as AAC related with primary EBV infection. She recovered completely by conservative treatment. US should be performed in consideration of the possibility of AAC when a patient with IM complains of epigastralgia

Late-onset peritoneal recurrence of advanced gastric cancer 20 years after primary resection

Late onset of peritoneal recurrence of gastric cancer more than 10 years after surgery is extremely rare, and only three cases have been reported. We present the case of a 61-year-old man who was diagnosed finally with peritoneal recurrence of gastric cancer 20 years after primary curative resection. As a result of small-bowel obstruction caused by peritoneal recurrence, diverting ileostomy with partial ileal resection was performed. The resected specimen revealed tubular adenocarcinoma that resembled the primary gastric cancer. The clinical course after the second operation was unfavorable and systemic chemotherapy had no effect. He died at 62 years of age, 21 years and 7 months after initial gastrectomy. Immunohistochemical analysis using antibodies against proliferating cell nuclear antigen (PCNA), Ki-67, and p53 was performed to investigate the phenotype of primary and recurrence cancer. Protein expression of proliferation markers such as PCNA and Ki-67 was down-regulated, but p53 was overexpressed at the site of recurrence. These data suggest that late peritoneal recurrence has a low proliferation rate and is resistant to chemoradiotherapy. In conclusion, we present late onset of peritoneal recurrence of gastric cancer more than 20 years after primary surgery, and speculate on the mechanism of late-onset recurrence in our case

A direct calculation of the free energy from the Bethe ansatz equation for the Heisenberg model

Thermodynamics of the XXX Heisenberg model is studied. The trace of the Boltzmann weight with respect to the Hilbert space is taken in the thermodynamic limit with the number of up-spins being fixed. The expression of the trace gives an explanation why the correct thermodynamic quantities are derived from the string hypothesis. Combining this with the previous result, we conclude that the free energy can be calculated only by assuming the Bethe ansatz equation. The method is more direct than other known methods which were used to derive the free energy.Comment: 52 pages, submitted to J. Math. Phy