Structural, Electronic, and Magnetic Properties of Surfaces, Interfaces, and Superlattices

Advances in all-electron local density functional theory approaches to complex materials structure and properties made possible by the implementation of new computational/theoretical algorithms on supercomputers are exemplified in our full potential linearized augmented plane wave (FLAPW) method. In this total energy self-consistent approach, high numerical stability and precision (to 10 in the total energy) have been demonstrated in a study of the relaxation and reconstruction of transition metal surfaces. Here we demonstrate the predictive power of this method for describing the structural, magnetic and electronic properties of several systems (surfaces, overlayers, sandwiches, and superlattices).

Orbital-dependent modifications of electronic structure across the magnetostructural transition in BaFe2As2

Laser angle-resolved photoemission spectroscopy (ARPES) is employed to investigate the temperature (T) dependence of the electronic structure in BaFe2As2 across the magnetostructural transition at T{N} approximately 140 K. A drastic transformation in Fermi surface (FS) shape across T{N} is observed, as expected by first-principles band calculations. Polarization-dependent ARPES and band calculations consistently indicate that the observed FSs at k{z} approximately pi in the low-T antiferromagnetic state are dominated by the Fe3d{zx} orbital, leading to the twofold electronic structure. These results indicate that magnetostructural transition in BaFe2As2 accompanies orbital-dependent modifications in the electronic structure.

The effect of co-existing solutes on arsenate removal with hydrotalcite compound

Hydrotalcite (HTAL-Cl), an inorganic anion exchanger, is of use as an adsorbent for the removal of arsenate (As(V)) in water systems. The adsorption properties of HTAL-Cl for As(V) and the effects of co-existing anions on the As(V) removal performance were investigated in this work. Under the conditions of pH>or=4, the adsorption capacity for As(V) gradually decreased with an increase of pH, but As(V) was removed effectively within the range of pH = 5-8. Co-existing anions interfered As(V) removal, and the effect decreased in the order of HPO(4)(2-) > HCO(3)(-) > SO(4)(2-) > Cl(-). In binary solute systems containing phosphate and As(V), the maximum adsorption capacity of HTAL-Cl was 0.95 mmol g(-1) for phosphate and 0.65 mmol g(-1) for As(V): the total of these values corresponded to the maximum adsorption capacity for As(V) in single solute systems. The adsorption isotherms in these binary solute systems were approximated by the following modified Langmuir equations:As(V): q(As) = 18.7 radicalC(As)/(1 + 21.5 radicalC(P) + 12.8 radicalC(As)), phosphate : q(P) = 33.1 radicalC(P)/(1 + 21.5 radicalC(P) + 12.8 radicalC(As)). The column adsorption experiments showed that the adsorbed As(V) was released by the phosphate adsorption, because phosphate was adsorbed more strongly on HTAL-CL than As(V).

[IgG4-related idiopathic retroperitoneal fibrosis: a case report]

A 75-year-old man visited our hospital with the complaint of lumbago due to bilateral hydronephrosis. Computed tomographic (CT) scan revealed a thick and homogeneous retroperitoneal soft-tissue mass with isodensity to the muscle, which extended from around the kidneys to the bladder. His serum IgG4 level was extremely high. He also had proptosis. He was diagnosed as having retroperitoneal fibrosis due to IgG4- related sclerosing disease, and treated with glucocorticoid and azathioprine. After 2 months, partial regression of the mass was observed.

A first-principles study on the Rashba effect in surface systems

The Rashba effect in several surface systems, Au(111), Au(110), Ag(111), Sb(111) and Si(111)-Bi, is studied by means of first-principles relativistic density-functional calculations. The importance of the asymmetric behavior around the surface atom is emphasized as a crucial factor to determine the magnitude of Rashba spin splitting in addition to the size of the spin-orbit coupling. The Rashba effect at the Brillouin-zone boundary is generally described with time-reversal symmetry. Distinctive features in the spin splitting and spin direction for a two-dimensional hexagonal system are discussed with the use of symmetry in the double group of k.

Micronization and Polymorphic Conversion of Tolbutamide and Barbital by Rapid Expansion of Supercritical Solutions

Rapid expansion of supercritical solutions (RESS) was applied to tolbutamide and barbital. The solubility in supercritical CO2 was determined to estimate the extraction efficiency roughly by a simple method and accurately by a direct spectrophotometric technique. The latter revealed that the solubility of tolbutamide was a function of applied pressure and temperature and was proportional to the pressure. No significant difference in solubility between polymorphic Forms I and II of tolbutamide was detected. Tolbutamide and barbital particles produced by the RESS were characterized by size distribution measurement, polymorph identification and morphological evaluation. Significant size reduction to micron or sub-micron level with narrow size distribution was achieved, while conventional mechanical grinding had only slight effect. The particle size was greatly affected by both extraction and expansion conditions. The lower the extraction temperature was, the smaller was the mean particle size. Higher extraction pressure resulted in smaller mean particle size when compared at the same extraction temperature. The mean particle size was reduced by lowering the spray nozzle temperature, by lowering the expansion chamber temperature, by increasing the CO2 amount per spray, and by increasing the exhaust gas flow rate. The RESS processing realized the polymorphic conversion as well. As for tolbutamide, three polymorphs (Forms I, II, and IV) out of four could be produced by changing the extraction conditions, and in the case of barbital, one polymorph (Form II) out of three was produced consistently.

[Adult Wilms' tumor mimicking adrenal tumor: case report]

A 33-year-old woman was referred to our hospital for further examination of a right adrenal mass 4.5 cm in diameter. Hormonal findings were normal. Computed tomography, magnetic resonance image and angiograpy demonstrated non-functioning adrenal tumor. Right nephrectomy was performed, because the tumor adhered firmly to the upper pole of the right kidney. The pathological diagnosis was nephroblastoma (nephroblastic type, complex subtype). Postoperative chemotherapy was started for stage III Wilms' tumor. However, peripheral neuropathy such as numbness of the fingers developed. Therefore, chemotherapy was discontinued in the fifth week. The patient is currently alive without recurrence 17 months postoperatively. In adult patients, postoperative chemotherapy for nephroblastoma is often interrupted due to side effects. Further studies on the protocol for adults is necessary.

[Cystoscopy-assisted partial cystectomy for paraganglioma of the urinary bladder]

A 39-year-old woman visited our hospital with a complaint of gross hematuria. Cystoscopy revealed a nodular tumor 3 cm in diameter in the posterior wall of the bladder. A transurethral resection was performed. This initial operation was complicated by unexpected intra-operative high blood pressure and visualization was obscured by bleeding. The histological diagnosis was paraganglioma. Therefore, a partial cystectomy was planned. Using cystoscopy, a 10 mm margin was identified and marked using electrocoagulation, followed by an open surgical procedure. After laparotomy, drainage veins were identified and ligated under the guidance of flexible cystoscopy lighting. Intra-operative blood pressure was stable during the operation, and the margin was negative for tumor.

The localization of proteins encoded by CRYM, KIAA1199, UBA52, COL9A3, and COL9A1, genes highly expressed in the cochlea

Genes that are highly expressed in the inner ear, as revealed by cDNA microarray analysis, may have a crucial functional role there. Those that are expressed specifically in auditory tissues are likely to be good candidates to screen for genetic alterations in patients with deafness, and several genes have been successfully identified as responsible for hereditary hearing loss. To understand the detailed mechanisms of the hearing loss caused by the mutations in these genes, the present study examined the immunocytochemical localization of the proteins encoded by Crym, KIAA1199 homolog, Uba52, Col9a3, and Col9a1 in the cochlea of rats and mice. Confocal microscopic immunocytochemistry was performed on cryostat sections. Ultrastructurally, postembedding immunogold cytochemistry was applied using Lowicryl sections. Crym protein was predominantly distributed in the fibrocytes in the spiral ligament, as well as the stria vascularis in rats. KIAA1199 protein homolog was localized in various supporting cells, including inner phalangeal, border, inner and outer pillar, and Deiters' cells. Uba52 protein was restrictedly localized within the surface of the marginal cells of the stria vascularis. Collagen type IX was found within the tectorial membrane as well as fibrocytes in the spiral ligament. The present results showed cell-specific localization of the encoded proteins of these highly expressed genes, indicating that the coordinated actions of various molecules distributed in different parts of the cochlea are essential for maintenance of auditory processing in the cochlea.

[Two cases of urethrovaginal fistula repaired by Martius labial-rotation flap]

Urethrovaginal fistulas are rare. In case 1, a 48-year-old woman had undergone transvaginal drainage for an paraurethral abscess. In case 2, a 33-year-old woman had undergone resection of vaginal varicocele with massive bleeding during pregnancy. Postoperatively both patients complained of total incontinence. Urethroscopy and urethrography revealed an urethrovaginal fistula in each case. Repair ofurethrovaginal fistula using Martius labial-rotation flap was performed and the fistula was closed in both cases. We concluded that repair of urethrovaginal fistula using Martius labial-rotation flap may be useful for patients with urethrovaginal fistula.

Isoflurane and sevoflurane during reperfusion prevent recovery from ischaemia in mitochondrial KATP channel blocker pretreated hearts

BACKGROUND AND OBJECTIVE

Inhalation anaesthetics given only during post-ischaemic reperfusion have some protective effect against reperfusion injury in the heart. Adenosine triphosphate-regulated mitochondrial potassium channels have been shown to be an important mediator of cardioprotection. Thus, we investigated whether 5-hydroxydecanoate, a putative mitochondrial potassium channel blocker, prevents the cardioprotective effect of volatile anaesthetics.

METHODS

Forty rats were randomly allocated to four groups of equal size: control group, 5-hydroxydecanoate group, 5-hydroxydecanoate + sevoflurane group and 5-hydroxydecanoate + isoflurane group. Seven minutes after the start of perfusion, normal saline (control group) or 5-hydroxydecanoate (the other groups) was administered. Ten minutes after the start of perfusion, the heart was rendered globally ischaemic for 10 min. One minute before the end of the ischaemic period, 2.7% sevoflurane or 1.4% isoflurane were administered in the 5-hydroxydecanoate + sevoflurane or 5-hydroxydecanoate + isoflurane groups respectively. The heart was reperfused for 10 min.

RESULTS

Adenosine triphosphate content at the end of reperfusion in the 5-hydroxydecanoate + sevoflurane group was significantly lower (P < 0.05) than those in the control and the 5-hydroxydecanoate + isoflurane groups (19.9 +/- 8.7, 28.1 +/- 3.4 and 30.4 +/- 2.3 micromol g(-1), respectively). In addition, the combination of inhalation anaesthetics and 5-hydroxydecanoate decreased the ratios of recovered hearts from ischaemia (5-hydroxydecanoate + sevoflurane group: 40%, 5-hydroxydecanoate + isoflurane group 50%).

CONCLUSION

5-hydroxydecanoate alone caused no significant changes in haemodynamics and myocardial metabolism. However, the combination of 5-hydroxydecanoate and volatile anaesthetics impaired the recovery from ischaemia. Although animal data cannot be extrapolated to human beings, we suggest that more attention be paid to patients on sulphonylurea drugs, which inhibit potassium channels, when they are anaesthetized with volatile anaesthetics.

Origin of the metallic properties of heavily boron-doped superconducting diamond

The physical properties of lightly doped semiconductors are well described by electronic band-structure calculations and impurity energy levels. Such properties form the basis of present-day semiconductor technology. If the doping concentration n exceeds a critical value n(c), the system passes through an insulator-to-metal transition and exhibits metallic behaviour; this is widely accepted to occur as a consequence of the impurity levels merging to form energy bands. However, the electronic structure of semiconductors doped beyond n(c) have not been explored in detail. Therefore, the recent observation of superconductivity emerging near the insulator-to-metal transition in heavily boron-doped diamond has stimulated a discussion on the fundamental origin of the metallic states responsible for the superconductivity. Two approaches have been adopted for describing this metallic state: the introduction of charge carriers into either the impurity bands or the intrinsic diamond bands. Here we show experimentally that the doping-dependent occupied electronic structures are consistent with the diamond bands, indicating that holes in the diamond bands play an essential part in determining the metallic nature of the heavily boron-doped diamond superconductor. This supports the diamond band approach and related predictions, including the possibility of achieving dopant-induced superconductivity in silicon and germanium. It should also provide a foundation for the possible development of diamond-based devices.

Laceration of gastric mucosa associated with dialysis-related amyloidosis

We report a 72-year-old female on long-term hemodialysis, who was admitted to the hospital because of hematemesis. On emergency laparotomy, pylorogastrectomy was performed. The resected specimen showed a giant hematoma and traversing fissure along the lesser curvature of the body of the stomach. Histologically, the specimen showed wide hematoma formation and amyloid deposits in the submucosal layer, especially in the wall of blood vessels. These deposits reacted positively to antihuman beta2-microglobulin antibody. The post-operative course was favorable, and the patient was discharged on the 35th hospital day. In this case, the laceration site on the gastric mucosa was almost intact and did not demonstrate ischemic change, suggesting that the giant hematoma was caused by submucosal vessel rupture, which led to the gastric mucosa laceration. To our knowledge, this is the first case of gastric mucosa laceration associated with dialysis-related amyloidosis.

Importance of Transition Zone Prostate Biopsies in Patients with Gray-Zone PSA Levels Undergoing the Ultrasound-Guided Systematic Ten-Biopsy Regimen for the First Time

INTRODUCTION

We analyzed the efficacy of routine transition zone biopsies for patients undergoing ultrasound-guided systematic prostate biopsies for the first time because of an elevated serum prostate-specific antigen (PSA) level.

PATIENTS AND METHODS

Using the systematic ten-biopsy regime, four additional transition zone biopsies were performed in 236 consecutive patients, because they showed an elevated PSA level (range 4.0- 9.9 ng/ml).

RESULTS

The overall prostate cancer detection rate was 21.2% (50/236). In 24 patients (48.0%), cancers were detected only in the peripheral zone, in 4 (8.0%) only in the transition zone, and in 22 (44.0%) in both zones. No distinguishing characteristics could be determined for the cancers detected in the transition zone only.

CONCLUSIONS

Although the cancer detection rate for the transition zone was significantly lower than for the peripheral zone, it was higher than that reported in most other studies which may have included biopsy specimens from patients with advanced prostate cancers. The usefulness of transition zone biopsies for the detection of early-stage prostate cancer, especially in patients with a PSA gray zone, can, therefore, not be denied.

Sevoflurane reduces dysrhythmias during reperfusion in the working rat heart

PURPOSE

The effects of sevoflurane on myocardial reperfusion injury have not been well studied. The purpose of this study was to determine the effects of sevoflurane on myocardial function, arrhythmia, and metabolism during reperfusion in an isolated working rat heart model.

METHODS

Thirty-two hearts were divided into four groups according to the timing of 2.5% sevoflurane administration: group I, control, no sevoflurane; group II, sevoflurane administered only before ischemia; group III, sevoflurane only during reperfusion; group IV, sevoflurane during the whole study period. Myocardial contractility, myocardial ATP, lactate, and glycogen levels were assessed in the reperfusion period following global heart ischemia of 15 min duration. The incidence and duration of ventricular fibrillation were also observed in the reperfusion period.

RESULTS

There was no difference in cardiac output and left ventricular dP/ dt max among the four groups at 10, 15, and 20 min after reperfusion. There was no difference in myocardial ATP, lactate and glycogen contents between the groups. The incidences of ventricular fibrillation during reperfusion were 100%, 63%, 100%, and 25% (P < 0.05 vs control), and the durations of ventricular fibrillation during reperfusion were 375 +/- 269, 104 +/- 98 (P < 0.05 vs control), 303 +/- 189, and 93 +/- 245 (P < 0.05 vs control) in groups I, II, III, and IV, respectively (mean +/- SD).

CONCLUSION

The administration of sevoflurane prior to reperfusion appears to provide myocardial protection, as assessed by reduced dysrhythmias during reperfusion.

Improvement of physicochemical properties of N-4472

The optimized formulation of N-4472, N-[2-(3,5-di-tert-butyl-4-hydroxyphenethyl)-4,6-difluorophenyl]-N'-[4-(N-benzylpiperidyl)] urea, which was a poorly water-soluble drug, was developed by utilizing the complexation between N-4472 and L-ascorbic acid (VC). It was found that the formulation with Gelucire((R)) 44/14, HCO-60((R)) and sodium dodecyl sulfate provided a self-microemulsifying system consisting of fine droplets in approximately 18 nm size with a narrow distribution. 1H-NMR spectroscopic study indicated that the N-4472/VC complex was molecularly incorporated into surfactant molecular assembly in the microemulsion droplets. It was found that the N-4472 microemulsion was stable at the pH range from 2.0 to 7.0, suggesting the stability in the gastrointestinal tract. When the microemulsion containing N-4472/VC complex was orally administrated in rats, high AUC value of N-4472 (2 to 4-fold) was observed in comparison with the aqueous solution containing N-4472/VC complex.

Improvement of physicochemical properties of N-4472 part I formulation design by using self-microemulsifying system

The optimization of oral dosage form formulation has been developed for N-4472, N-[2-(3,5-di-tert-butyl-4-hydroxyphenethyl)-4,6-difluorophenyl]-N'-[4-(N-benzylpiperidyl)] urea, which was a poorly water-soluble drug having a lipid-lowering effect. Formulations that contained various surfactants and water-soluble polymers were prepared and the solubility of N-4472 was evaluated in JP XIV first fluid (pH 1.2), JP XIV second fluid (pH 6.8), and distilled water. The highest solubility of N-4472 was achieved when L-ascorbic acid (VC), Gelucire 44/14, and HCO-60 were used as additives. It was confirmed that this formulation could create microemulsion droplets with a mean droplet size of approximately 20 nm and a sharp droplet distribution pattern in JP XIV first fluid, JP XIV second fluid, and distilled water. When JP XIV second fluid was used as a dissolution medium, however, an eventual decrease of solubility was observed, that is, the fluid became white and cloudy as time passed. It was found that the addition of sodium dodecyl sulfate (SDS) was effective to prevent the lowering of solubility, and that a weight ratio of 1.0/1.5/11.4/4.9/3.8 for N-4472/VC/Gelucire 44/14/HCO-60/SDS was optimum for the self-microemulsifying formulation. It was assumed that electrostatic repulsion of microemulsion droplets and an increase of the cloud point by the addition of SDS were responsible for the successful formation of a stable microemulsion.