Projected entangled-pair states can describe chiral topological states.

We show that projected entangled-pair states (PEPS) in two spatial dimensions can describe chiral topological states by explicitly constructing a family of such states with a nontrivial Chern number. They are ground states of two different kinds of free-fermion Hamiltonians: (i) local and gapless; (ii) gapped, but with hopping amplitudes that decay according to a power law. We derive general conditions on topological free-fermionic projected entangled-pair states that show that they cannot correspond to exact ground states of gapped, local parent Hamiltonians and provide numerical evidence demonstrating that they can nevertheless approximate well the physical properties of topological insulators with local Hamiltonians at arbitrary temperatures.

Potential antidepressant properties of Radix Polygalae (Yuan Zhi).

Radix Polygalae ("Yuan Zhi", the roots of Polygala tenuifolia Willd., YZ) is an important herb used in traditional Chinese medicine to mediate depression. The present study was designed to verify the antidepressant effects of the standardized YZ ethanol extract (YZE) and its four fractions YZ-30, YZ-50, YZ-70 and YZ-90 on the tail suspension (TST) and forced swimming test (FST). Furthermore, the standardization of the fractions obtained from the separation procedures was carried out by high-performance liquid chromatography (HPLC)-fingerprint. The YZ-50 fraction (Oligosaccharide esters--enriched, oral (200 mg/kg) showed a significant anti-immobility like effects. The data of YZ-50 on the corticosterone-induced injure of SH-SY5Y human neuroblastoma cell indicated that YZ-50 may have biological effects on neuroprotection. Proliferation of cell lines was assessed by dimethylthiazoldiphenyltetrazoliumbromide (MTT) and 5-bromo-2'-deoxyuridine (BrdU) incorporation assays. It was found that YZ-50 and its two bioactive compounds, 3,6'-di-o-sinapoyl-sucrose (DISS) and tenuifoliside A(TEA) showed protection activities in SY5Y cells from the lesion. By using bioassay-screening methods, our results indicate that the presence of oligosaccharide esters such as DISS and TEA in this herb may be responsible for the cytoprotective activity effects.

Surgical treatment of bronchiectasis: 10 years' experience.

BACKGROUND: Since antibiotic therapy and vaccination have been widely used in medical practice, the incidence of bronchiectasis has decreased steadily. The principal role of surgery associated with this disease is for the treatment of complications. We present an analysis of surgical results during a 10-year period. METHODS: The medical records of bronchiectasis patients who were surgically treated were retrospectively reviewed from July, 1987, to March, 1998. The surgical indications, complications and recurrences of bronchiectasis were evaluated. RESULTS: A total of 41 bronchiectasis patients underwent surgical treatment from 1987 to 1998 at our hospital. There were 18 males (mean age, 37.8 +/- 15.3 years; range, 16-73 years), and 23 females (mean age, 33 +/- 7.1 years; range, 21-46 years). The indications for surgery were hemoptysis in 30, failed medical treatment in eight, suspected neoplasm in two and retention of a foreign body in one patient. Anatomic resections of the diseased sites were carried out more frequently on the left lower lobes of the lungs. In total, there were 20 left lower lobes, five right lower lobes, 10 left lingular lobes, five right middle lobes, four left upper lobes and one right upper lobe that required surgery. Surgical complications included hemorrhage in one patient, bronchopleural fistula in one and galactorrhea in one patient. The follow-up intervals were from two to 131 months (mean, 72.5 +/- 37.6 months; median, 74 months). There were two cases of recurrent symptoms and six cases of recurrent hemoptysis; all were easily controlled by medication. There were no mortalities. CONCLUSIONS: Surgical treatment of bronchiectasis yields immediate resolution of symptoms, better quality of life and no mortalities. Cessation of smoking, avoiding air pollution and careful medical follow-up are mandatory.

Colorectal perforation with barium enema in the elderly: case analysis with the POSSUM scoring system.

Colorectal perforation is a serious complication of barium-enema examination, as the resultant contamination of the intraperitoneal or extraperitoneal space may result in a severe septic course. Between 1 October 1993 and 30 September 1996, four patients had colorectal injuries after barium-enema examinations at the Far Eastern Memorial Hospital, Taipei, Taiwan. Their mean age was 80 years and three of them died, despite the implementation of early and aggressive treatment. To examine the differences between this high crude mortality rate and reports of zero mortality, we retrospectively analyzed the data with the well established predictive surgical scoring system, the Physiological and Operative Severity Score for the enUmeration of Morbidity and mortality (POSSUM), to estimate the potential risk of death in these four patients.