Thin film growth of CaAgAs by molecular beam epitaxy.

We have grown thin films of CaAgAs by molecular beam epitaxy, which was theoretically proposed to be a topological insulator. The temperature dependence of resistivity and the carrier concentration at 4 K were similar to the reported results of bulk samples. However, the magnetoresistance exhibited a steep increase at low magnetic fields, a behavior not observed for bulk samples. This steep increase of resistivity is ascribable to the weak antilocalization effect and provides clues to the nature of the topological surface state of CaAgAs.

p-wave superconductivity in iron-based superconductors.

The possibility of p-wave pairing in superconductors has been proposed more than five decades ago, but has not yet been convincingly demonstrated. One difficulty is that some p-wave states are thermodynamically indistinguishable from s-wave, while others are very similar to d-wave states. Here we studied the self-field critical current of NdFeAs(O,F) thin films in order to extract absolute values of the London penetration depth, the superconducting energy gap, and the relative jump in specific heat at the superconducting transition temperature, and find that all the deduced physical parameters strongly indicate that NdFeAs(O,F) is a bulk p-wave superconductor. Further investigation revealed that single atomic layer FeSe also shows p-wave pairing. In an attempt to generalize these findings, we re-examined the whole inventory of superfluid density measurements in iron-based superconductors and show quite generally that single-band weak-coupling p-wave superconductivity is exhibited in iron-based superconductors.

Selective mass enhancement close to the quantum critical point in BaFe2(As1-x P x )2.

A quantum critical point (QCP) is currently being conjectured for the BaFe2(As1-x P x )2 system at the critical value x c ≈ 0.3. In the proximity of a QCP, all thermodynamic and transport properties are expected to scale with a single characteristic energy, given by the quantum fluctuations. Such a universal behavior has not, however, been found in the superconducting upper critical field H c2. Here we report H c2 data for epitaxial thin films extracted from the electrical resistance measured in very high magnetic fields up to 67 Tesla. Using a multi-band analysis we find that H c2 is sensitive to the QCP, implying a significant charge carrier effective mass enhancement at the doping-induced QCP that is essentially band-dependent. Our results point to two qualitatively different groups of electrons in BaFe2(As1-x P x )2. The first one (possibly associated to hot spots or whole Fermi sheets) has a strong mass enhancement at the QCP, and the second one is insensitive to the QCP. The observed duality could also be present in many other quantum critical systems.

Intrinsic and extrinsic pinning in NdFeAs(O,F): vortex trapping and lock-in by the layered structure.

Fe-based superconductors (FBS) present a large variety of compounds whose properties are affected to different extents by their crystal structures. Amongst them, the REFeAs(O,F) (RE1111, RE being a rare-earth element) is the family with the highest critical temperature Tc but also with a large anisotropy and Josephson vortices as demonstrated in the flux-flow regime in Sm1111 (Tc ∼ 55 K). Here we focus on the pinning properties of the lower-Tc Nd1111 in the flux-creep regime. We demonstrate that for H//c critical current density Jc at high temperatures is dominated by point-defect pinning centres, whereas at low temperatures surface pinning by planar defects parallel to the c-axis and vortex shearing prevail. When the field approaches the ab-planes, two different regimes are observed at low temperatures as a consequence of the transition between 3D Abrikosov and 2D Josephson vortices: one is determined by the formation of a vortex-staircase structure and one by lock-in of vortices parallel to the layers. This is the first study on FBS showing this behaviour in the full temperature, field, and angular range and demonstrating that, despite the lower Tc and anisotropy of Nd1111 with respect to Sm1111, this compound is substantially affected by intrinsic pinning generating a strong ab-peak in Jc.

Fermi surface and pseudogap evolution in a cuprate superconductor.

The unclear relationship between cuprate superconductivity and the pseudogap state remains an impediment to understanding the high transition temperature (T(c)) superconducting mechanism. Here, we used magnetic field-dependent scanning tunneling microscopy to provide phase-sensitive proof that d-wave superconductivity coexists with the pseudogap on the antinodal Fermi surface of an overdoped cuprate. Furthermore, by tracking the hole-doping (p) dependence of the quasi-particle interference pattern within a single bismuth-based cuprate family, we observed a Fermi surface reconstruction slightly below optimal doping, indicating a zero-field quantum phase transition in notable proximity to the maximum superconducting T(c). Surprisingly, this major reorganization of the system's underlying electronic structure has no effect on the smoothly evolving pseudogap.

Impaired intrinsic chiral inversion activity of ibuprofen in rats with adjuvant-induced arthritis.

1. The effects of adjuvant-induced arthritis on the chiral inversion of 'profens', a type of non-steroidal anti-inflammatory drug, have hardly been investigated. The authors investigated the effects of adjuvant-induced arthritis on the chiral inversion of ibuprofen using freshly isolated rat hepatocytes. 2. S- or R-ibuprofen was incubated with hepatocytes isolated from control and adjuvant-induced arthritis rats in the absence of the serum. In the hepatocyte system the chiral inversion rate constant of R- to S-ibuprofen and the metabolic rate constants of both enantiomers in adjuvant-induced arthritis rats were significantly decreased to about 64-80% of the corresponding values in control rats. In contrast, the addition of serum from each group to the corresponding hepatocyte medium resulted in no significant differences in these rate constants between control and adjuvant-induced arthritis rats. 3. With regard to chiral inversion enzymes, adjuvant-induced arthritis decreased the messenger RNA levels of acyl-coenzyme A synthetase (ACS) isoforms, but not 2-arylpropionyl-CoA epimerase, compared with control rats. 4. Chiral inversion of R- to S-ibuprofen was inhibited by triacsin C, a specific inhibitor of ACS1. 5. The results suggest that adjuvant-induced arthritis induces down-regulation of ACS enzymes involved in chiral inversion of R- to S-ibuprofen in rats.

Evidence of two dimensionality in quasi-one-dimensional cobalt oxides.

The quasi-one-dimensional (Q1D) cobalt oxides A(N + 2)Co(n + 1)O(3n + 3) (A = Ca, Sr, and Ba, n = 1 - infinity) were investigated by muon-spin spectroscopy under applied pressures of up to 1.1 GPa. The relationship between the onset Néel temperature T(on)(N) and the interchain distance (d(ic)), which increases monotonically with n, is well fitted by the formula T(N)/T(N,0) = (1 - d(ic)/d(ic,o)(beta), here for T(on)(N) approximately 100 K for Ca(3)Co(2)O(6) (n = 1) and approximately 15 for BaCoCoO(3) (n = infinity at ambient P. The T(on)(N) - d(ic) curve also predicts a large dependence of Y(N) for the compounds with n > or = 5, i.e., in the vicinity of , while the compounds show only a very small effect. Indeed, our high-pressure mu(+) results show that of BaCoO(3) is enhanced by with a slope of 2.2 K(Gpa), whereas no detectable changes by P for both Ca(3)Co(2)O(6) and Sr(4)Co(3)O(9) (n = 2). This clearly confirms the role of the 2D-antiferromagnetic interaction on T(on)(N) in the Q1D cobalt oxides.

Three-dimensional fermi-liquid ground state in the quasi-one-dimensional cuprate PrBa(2)Cu(4)O(8).

The interchain resistivity of PrBa(2)Cu(4)O(8) has been measured in high magnetic fields up to 30 T. Co-herent interchain transport at low temperatures is destroyed by a large magnetic field applied perpendicular to the CuO chains. Comparisons with quasiclassical transport theory provide strong experimental support for a three-dimensional Fermi-liquid ground state in PrBa(2)Cu(4)O(8), despite extreme anisotropy in its electronic properties and the presence of strong electron correlations.

Squalene synthase inhibitors reduce plasma triglyceride through a low-density lipoprotein receptor-independent mechanism.

Inhibitors of squalene synthase are considered to be candidate drugs to reduce both plasma cholesterol and triglyceride. However, little is known about the mechanism of squalene synthase inhibitor-specific effect on plasma triglyceride. In this study, we confirmed the triglyceride-lowering effect of ER-27856, a potent squalene synthase inhibitor prodrug, in rhesus monkeys. To determine the role of low-density lipoprotein (LDL) receptor in the triglyceride-lowering effect of squalene synthase inhibitors, we intravenously administered ER-28448, the active form of ER-27856, to Watanabe heritable hyperlipidemic (WHHL) rabbits for 4 days. In heterozygotes, ER-28448 reduced plasma cholesterol and triglyceride by 52% and 37%, respectively. In homozygous rabbits, in contrast, ER-28448 lowered plasma triglyceride by 40% but did not lower plasma cholesterol. Orally administered ER-27856 reduced plasma triglyceride in homozygous animals but atorvastatin and bezafibrate did not. In hepatocytes isolated from homozygous WHHL rabbits, squalene synthase inhibitors but not atorvastatin reduced triglyceride biosynthesis. These data demonstrate that squalene synthase inhibitors reduced plasma triglyceride through an LDL receptor-independent mechanism, which was distinct from that of the triglyceride-lowering action of atorvastatin or bezafibrate. The reduction of hepatic triglyceride biosynthesis may play an important role in the hypotrigyceridemic action of squalene synthase inhibitors.

Combined trisomy 9P and Shprintzen syndrome resulting from a paternal t(9;22).

The authors report on a female infant with partial trisomy 9 (pter-->q12) together with partial monosomy 22 (pter-->q11.23) that included DiGeorge critical region (DGCR), as a result of adjacent-2 disjunction. In addition to the clinical features characteristic of trisomy 9p syndrome, the patient had Truncus arteriosus type A2, bilateral hydronephrosis, palatal anomaly, retrognathia, and laryngeal hypotonia, which are likely to be attributed to 22q11.2 deletion. This patient appears to be the first reported case with such unbalanced translocation resulting from a paternal reciprocal translocation. For live birth, the risk for male carrier is 8.7-17.4%. It is important to consider this higher risk when counseling. Precise study concerning the presence of the DGCR can facilitate in the better understanding of the condition.

Improved glucose tolerance via enhanced glucose-dependent insulin secretion in dipeptidyl peptidase IV-deficient Fischer rats.

Glucagon-like peptide-1 (GLP-1) is an incretin, which induces glucose-dependent insulin secretion. GLP-1 is rapidly degraded by dipeptidyl peptidase IV (DPPIV) after its release. We investigated whether DPPIV-deficient F344/DuCrj rats show improved glucose tolerance when compared with DPPIV-positive F344/Jcl rats. Oral glucose tolerance test indicated improved glucose tolerance in F344/DuCrj rats, but blood glucose levels of the two strains were almost the same 120 min after the glucose bolus. Valine-pyrrolidide, a DPPIV inhibitor, had no effect on the glucose tolerance of F344/DuCrj rats, but improved that of F344/Jcl rats. Enhanced insulin secretion and high plasma active GLP-1 levels were detected in an intraduodenal glucose tolerance test. Glucose tolerance is improved in DPPIV-deficient F344/DuCrj rats via enhanced insulin release mediated by high active GLP-1 levels. Our results suggest that DPPIV inhibition is a rational strategy to treat diabetic patients by improving glucose tolerance with low risk of hypoglycemia.

Anisotropic optical spectra of PrBa2Cu4O8: possible Tomonaga-Luttinger liquid response of the quasi-one-dimensional metallic CuO double chains.

The optical spectra of PrBa2Cu4O8 show large in-plane anisotropy. For the a polarization (E perpendicular chain), the spectrum is characterized by a gap of 1.4 eV, indicating the charge-transfer insulating nature of the CuO2 planes. For the metallic chain direction (E // b), the spectrum deviates from a simple Drude response; reflectivity R(b)(omega) shows a sharp edge at approximately 1 eV but it also shows a dip at approximately 15 meV, which splits the conductivity spectrum into two parts--a zero-energy mode with small weight and a pronounced 40 meV mode. These features are discussed in terms of a Tomonaga-Luttinger liquid in a doped 1D Mott insulator and compared with 1D Bechgaard salts.

Complete agenesis of the dorsal pancreas.

Pancreatic anomalies are occasionally reported, but complete agenesis of the dorsal pancreas is extremely rare. We report a 47-year-old woman with complete agenesis of the dorsal pancreas. This patient initially presented with jaundice. Computed tomography did not reveal the pancreatic corpus or tail. Endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography did not visualize the dorsal pancreatic duct. Choledochojejunostomy was performed because she had obstructive jaundice. At laparotomy, there was an enlarged pancreatic head, but no distal pancreas was seen. Histological examination of the pancreatic biopsy specimen showed scattered islets of Langerhans in diffuse fibrosis, with destruction of the glandular parenchyma. This case was diagnosed as complete agenesis of the dorsal pancreas.

Experimental study on paratumoral injection of cisplatin-loaded microspheres for gastric cancer.

Microspheres from glycolide-L-lactide copolymers incorporating cisplatin (CDDP-MS) were prepared to evaluate the sustained release and anticancer effect by paratumoral injection on the gastric cancer with regional lymphnode metastases induced by VX2 tumor in rabbits. In the first set of experiment, the rabbits were divided into three groups subjected to treatment and compared the tissue cisplatin distribution. In the first group (CDDP-MS pt group), 1 mg/kg of cisplatin was administered by the method of paratumoral injection in the form of CDDP-MS. In the second group (CDDP solution pt group), the same dose was given in the form of CDDP aqueous solution in the same way and in the third group (CDDP solution i.v. group), the same dose was intravenously administered. In the second set of experiment, after twice of each therapy the anticancer effects were compared between CDDP-MS pt and CDDP solution i.v. groups. In results, the platinum concentrations of the tumor and regional lymphnodes were 3.14 +/- 6.22, 0.65 +/- 0.79 micrograms/g in the first group, 0.43 +/- 0.39, 0.16 +/- 0.16 microgram/g in the second group and 0.03 +/- 0.01, 0.07 +/- 0.05 microgram/g in the third group, respectively.

Clinicopathological features of esophageal cancer simultaneously associated with gastric cancer.

BACKGROUND AND OBJECTIVES: We usually use the stomach for esophageal substitution in the surgical treatment of esophageal cancer, although it is often associated with gastric cancer. In order to improve the likelihood of safe and curative surgery of esophageal cancer, we investigated the clinicopathological characteristics of synchronous esophageal and gastric cancer. METHODS: Among 288 patients with primary esophageal cancer who had undergone esophageal resection, this cancer was associated with gastric cancer in 11 cases, and 1,416 gastric cancer patients operated on during the same period, were analyzed. The clinicopathological characteristics and surgical procedures of the 11 patients were compared with those of the other esophageal cancer patients and with those with the gastric cancer only. RESULTS: There were significant differences between the synchronous double cancer and the gastric cancer only in sex (P < 0.01) and location of the gastric cancer (P < 0.05). All of the patients with the synchronous double cancer were men, and the incidence of patients with cardiac cancer was high. CONCLUSIONS: Our findings suggest that, in cases of synchronous esophageal and gastric cancer, an adequate surgical procedure must be chosen in terms of the stage, location, and operative burden.

A case of esophagectomy for corrosive esophageal stricture caused by swallowing strong alkali. A case report.

We report herein the case of a 22-year old woman who underwent esophagectomy for corrosive esophageal stricture. This patient with mental disturbance swallowed a strong alkali in a suicide attempt and suffered from esophageal stenosis instead of steroid therapy. Because the stiffness and stricture of the esophagus proved to be refractory, transhiatal esophagectomy by blunt finger with gastroesophagostomy was performed four months after injury. Operative findings revealed severe stiffness and inflammation of the esophagus which had spread to the adjacent organs, especially the carina. As for pathological findings, most of the esophageal mucosa showed defects resulting from infiltration of inflammatory cells and capillary vascularization from the lamina propria to the extra-esophageal wall. The postoperative course was uneventful and perioperative psychological state had been stable leading to a decrease in tranquilizer dosage. This experience indicates that esophagectomy is the treatment of choice for such mental disturbed patients with severe stenosis.

Surgical treatment of patients with psychiatric disorders: a review of 21 patients.

Between January 1985 and September 1994, 21 patients with psychiatric disorders underwent various forms of surgery at our hospital. There were 12 men and 9 women with an average age of 57.6 years. The coexisting psychiatric disorders were schizophrenia in 15 patients, depression in 2, dementia in 2, mental retardation with epilepsy in 1, and Parkinson's disease in 1. All the patients had been receiving neuroleptic medications for a long period. The indications for surgery were: cholelithiasis in 6 patients, acute appendicitis in 4, perforation of the small intestine in 3, incarceration of an inguinal hernia in 2, and esophageal cancer, stomach cancer, bleeding from a gastric ulcer, perforation of a duodenal ulcer, strangulating ileus, and burns in 1 patient each, respectively. All of the patients who underwent elective surgery were given epidural anesthesia with or without general anesthesia. Antipsychotic medications were given until just prior to surgery and recommenced concurrent with the first meal. Abnormal behavior was observed in 11 patients (52.4%) postoperatively, but all the patients were discharged in accordance with recovery from their surgical disorder. Intra- and postoperative hypotension resistant to intravenous catecholamine administration was recognized in 9 patients (42.9%), and this peculiar complication should be borne in mind when patients with psychiatric disorders require surgical management.