Atomic-scale interpretation of the quantum oscillations in cuprate superconductors.

Cuprate superconductors display unusual features in bothkspace and real space as the superconductivity is suppressed-a broken Fermi surface, charge density wave, and pseudogap. Contrarily, recent transport measurements on cuprates under high magnetic fields report quantum oscillations (QOs), which imply rather a usual Fermi liquid behavior. To settle the disagreement, we investigated Bi2Sr2CaCu2O8+δunder a magnetic field in an atomic scale. A particle-hole (p-h) asymmetrically dispersing density of states (DOSs) modulation was found at the vortices on a slightly underdoped sample, while on a highly underdoped sample, no trace of the vortex was found even at 13 T. However, a similar p-h asymmetric DOS modulation persisted in almost an entire field of view. From this observation, we infer an alternative explanation of the QO results by providing a unifying picture where the aforementioned seemingly conflicting evidence from angle-resolved photoemission spectroscopy, spectroscopic imaging scanning tunneling microscopy, and magneto-transport measurements can be understood solely in terms of the DOS modulations.

Cooper Pair Density of Bi2Sr2CaCu2O8+ x in Atomic scale at 4.2 K.

In pursuit of the elusive mechanism of high- T C superconductors (HTSC), spectroscopic imaging scanning tunneling microscopy (SI-STM) is an indispensable tool for surveying local properties of HTSC. Since a conventional STM utilizes metal tips, which allow the examination of only quasiparticles and not superconducting (SC) pairs, Josephson tunneling using STM has been demonstrated by many authors in the past. An atomically resolved scanning Josephson tunneling microscopy (SJTM), however, was realized only recently on Bi2Sr2CaCu2O8+ x (Bi-2212) below 50 mK and on the Pb(110) surface at 20 mK. Here we report the atomically resolved SJTM on Bi2Sr2CaCu2O8+ x at 4.2 K using Bi-2212 tips created in situ. The I- V characteristics show clear zero bias conductance peaks following Ambegaokar-Baratoff (AB) theory. A gap map was produced for the first time using an atomically resolved Josephson critical current map I C( r) and AB theory. Surprisingly, we found that this new gap map is anticorrelated to the gap map produced by a conventional method relying on the coherence peaks. Quasiparticle resonance due to a single isolated zinc atom impurity was also observed by SJTM, indicating that atomically resolved SJTM was achieved at 4.2 K. Our result provides a starting point for realizing SJTM at even higher temperatures, rendering possible investigation of the existence of SC pairs in HTSC above the T C.

Liver-Wrapping, Nitric Oxide-Releasing Nanofiber Downregulates Cleaved Caspase-3 and Bax Expression on Rat Hepatic Ischemia-Reperfusion Injury.

BACKGROUND: Hepatic ischemia-reperfusion injury (IRI) is an important determinant of the outcome of hepatic surgery, including re-section and transplantation. Previous studies have shown that nitric oxide (NO) has a protective effect against IRI. Therefore, many studies have examined methods for supplying NO. In this study, we investigated the effect of NO-releasing nanofibers on hepatic IRI in a rat model. METHODS: Male Sprague-Dawley rats were divided into 4 groups: control, IRI only (n = 3); group 1, hepatic IRI and liver-wrapping with nanofiber lacking NO (n = 4); group 2, hepatic IRI and liver-wrapping with NO rapid-releasing nanofiber (n = 4); and group 3, hepatic IRI and liver-wrapping with NO slow-releasing nanofiber (n = 5). RESULTS: The levels of aspartate aminotransferase and alanine aminotransferase were not significantly different between groups. On the basis of Western blots, Bax/ß-actin levels were significantly lower in group 2 than in group 3 (P < .01). Cleaved Caspase-3/ß-actin levels were significantly lower in group 2 than in the control, group 1, and group 3 (P < .05, .01, and .01, respectively). However, there were no significant differences in Bcl-2/ß-actin between groups. CONCLUSIONS: The liver-wrapping NO rapid-releasing nanofiber downregulated cleaved Caspase-3 and Bax expression. It has a protective effect by reducing apoptosis in hepatic IRI in rats.

Improved design for a low temperature scanning tunneling microscope with an in situ tip treatment stage.

The Low Temperature Scanning Tunneling Microscope (LT-STM) is an extremely valuable tool not only in surface science but also in condensed matter physics. For years, numerous new ideas have been adopted to perfect LT-STM performances-Ultra-Low Vibration (ULV) laboratory and the rigid STM head design are among them. Here, we present three improvements for the design of the ULV laboratory and the LT-STM: tip treatment stage, sample cleaving stage, and vibration isolation system. The improved tip treatment stage enables us to perform field emission for the purpose of tip treatment in situ without exchanging samples, while our enhanced sample cleaving stage allows us to cleave samples at low temperature in a vacuum without optical access by a simple pressing motion. Our newly designed vibration isolation system provides efficient space usage while maintaining vibration isolation capability. These improvements enhance the quality of spectroscopic imaging experiments that can last for many days and provide increased data yield, which we expect can be indispensable elements in future LT-STM designs.

Everolimus-Induced Systemic Serositis After Simultaneous Liver and Kidney Transplantation: A Case Report.

Although everolimus, a mammalian target of rapamycin inhibitor, has been used as a potent immunosuppressive agent in organ transplantation, data regarding its adverse effect profile compared with that of sirolimus in clinical circumstances are limited. A 50-year-old man who underwent simultaneous liver and kidney transplantation 14 months previously was admitted with large pleural effusion, pericardial effusion, and ascites. Laboratory findings and cultures for possible infectious causes were all negative. Pericardial window surgery with drainage of the pericardial fluid was performed on day 3. Pleural and pericardial biopsy revealed non-specific inflammation without evidence of malignant cells. Everolimus was discontinued and replaced by mycophenolate mofetil on day 4. Significant clinical improvement was observed after discontinuation of everolimus, and follow-up echocardiography and chest radiography showed no recurrence of the pericardial or pleural effusion after discharge.

Remote Preconditioning on Rat Hepatic Ischemia-Reperfusion Injury Downregulated Bax and Cleaved Caspase-3 Expression.

OBJECTIVE: Hepatic ischemia-reperfusion injury (IRI) is considered a major cause of hepatic damage in liver surgery. The aim of this study was to investigate the effect of the remote ischemic perconditioning method on hepatic IRI in a rat model. METHODS: Seventeen rats underwent hepatic IRI for 30 minutes followed by reperfusion, and were divided into 3 groups: group I, only hepatic IRI (n = 5); group II, hepatic IRI with remote perconditioning (n = 7); and group III, hepatic IRI with remote postconditioning (n = 5). RESULTS: For Bax/ß-actin, mean values of the 3 groups (±standard deviation) were 1.29 ± 0.26 (group I), 0.89 ± 0.15 (group II), and 1.02 ± 0.23 (group III). The level of Bax/ß-actin in group II was significantly lower than in group I (P < .01). The cleaved Caspase-3/ß-actin ratio for groups I, II, and III was 0.93 ± 0.22, 0.46 ± 0.16, and 0.63 ± 0.22, respectively. The level of cleaved Caspase-3/ß-actin in groups II and III were significantly lower than in group I (P < .01 and P < .05, respectively). The Bcl-2/ß-actin ratio for groups I, II, and III was 1.01 ± 0.09, 1.19 ± 0.39, and 1.20 ± 0.12, respectively. However, there were no significant difference between groups II and III and group I. CONCLUSIONS: The remote perconditioning on rat hepatic IRI downregulated the Bax and cleaved Caspase-3 expression.

Release and toxicity comparison between industrial- and sunscreen-derived nano-ZnO particles.

Many consumer products containing ZnO have raised concern for safety in regard to environmental impact and the public health. Widely used sunscreens for protecting against UV and avoiding sunburns represent a great exposure to nano-ZnO, one of the ingredients commonly applied in sunscreens. Applying nanoproducts on beaches may release nanoparticles unintentionally into the ocean. Despite the accumulation of such nanoproducts in the ocean harming or being detrimental to critical marine organisms, few studies have investigated the release and potential toxicity of nanoparticles extracted from products and compared them with those from industrial-type nanoparticles. Results show that the cytotoxicity of both industrial- and sunscreen-derived nano-ZnO to the marine diatom algae, Thalassiosira pseudonana, increased as exposure increases over time, as measured by growth inhibition (%) of the algae at a constant concentration of nano-ZnO (10 mg/L). The extent of toxicity appeared to be higher from industrial-type nano-ZnO compared with sunscreen-extracted nano-ZnO, though the extent becomes similar when concentrations increase to 50 mg/L. On the other hand, at a fixed exposure time of 48 h, the cytotoxicity increases as concentrations increase with the higher toxicity shown from the industrial-type compared with sunscreen-induced nano-ZnO. Results indicate that while industrial-type nano-ZnO shows higher toxicity than sunscreen-derived nano-ZnO, the release and extent of toxicity from nano-ZnO extracted from sunscreen are not trivial and should be monitored for the development of safe manufacturing of nanomaterials-induced products.

Outcomes of expanded-criteria deceased donor kidney transplantation in a single center.

BACKGROUND: In an effort to expand the deceased donor pool, transplant centers have accepted expanded-criteria donors as appropriate for many of the patients in the deceased donor pool. We investigated expanded-criteria deceased donor kidney transplantation and compared the outcomes of kidney transplantation according to donor types. METHODS: We retrospectively analyzed 88 kidney transplantations performed between June 2006 and December 2012. We divided the patient into 4 groups: SCDD, standard-criteria deceased donor; ECDD, expanded-criteria deceased donor; ECMO, donor under extracorporeal membrane oxygenation support; living donor. RESULTS: Deceased and living donor kidney transplantations were performed in 52 (59.1%) and 36 (40.9%) cases, respectively. Among deceased donors, 31 (35.2%) were standard-criteria donors and 14 cases (15.9%) were expanded-criteria donors. Seven (8.0%) donors were under extracorporeal membrane oxygenation support. Mean follow-up was 26.1 ± 20 months. Average number of HLA mismatches among the donor types was 3.39, 3.07, 3.0, and 2.94 in SCDD, ECDD, ECMO, and living donor groups, respectively (P = .708). Delayed graft function occurred in 2 (6.9%), 3 (21.4%), 3 (42.9%), and 3 (8.3%) patients in the SCDD, ECDD, ECMO, and living donor groups, respectively (P = .043). Episodes of acute rejection within a year occurred in 14 (45.2%), 2 (14.3%), 1 (14.3%), and 6 (16.7%) patients in the SCDD, ECDD, ECMO, and living donor groups, respectively (P = .029). Renal functions after kidney transplantation at 3 months, 6 months, 9 months, and 1 year were not significantly different according to donor types. Graft survival was not different among the different donor types (87.1%, 92.8%, 85.7%, 91.7% in SCDD, ECDD, ECMO, and living donor groups, respectively; P = .67). Patient survival was not different among the different donor types (87.1%, 92.9%, 100%, 97.2% in SCDD, ECDD, ECMO, and living donor group, respectively; P = .36). CONCLUSION: The use of expanded-criteria deceased donor had no impact on graft or patient survival after kidney transplantation.

Expression of transforming growth factor-beta1 and hypoxia-inducible factor-1alpha in renal transplantation.

Chronic allograft nephropathy (CAN) includes pathologic changes of interstitial fibrosis, tubular atrophy, and fibrous intimal thickening. Transforming growth factor (TGF)-beta1 is a fibrogenic cytokine involved in renal allograft fibrosis. Hypoxia-inducible factor (HIF)-1alpha is induced as an adaptive response to hypoxia triggering the production of fibrogenic cytokines such as TGF-beta1. Between January 1995 and February 2005, we performed 71 renal allograft biopsies in 61 recipients. Immunohistochemical studies were performed with an immunoperoxidase technique using as the primary antibody either a rabbit anti-human TGF-beta1 polyclonal or a mouse anti-human HIF-1alpha monoclonal reagent. The glomerular TGF-beta1 expression in recipients diagnosed with glomerulonephritis was significantly greater than other pathologic groups (P < .05), and the glomerular TGF-beta1 expression in the heavy proteinuria group (> or =2.5 g/d) was significantly greater than the low proteinuria group (<1.0 g/d; P < .05). The tubular and interstitial TGF-beta1 and HIF-1alpha expressions in CAN were greater than in other groups (P < .05). The tubular TGF-beta1 expression among the graft loss group was significantly greater than the graft function group (P < .05).

Human p16gamma, a novel transcriptional variant of p16(INK4A), coexpresses with p16(INK4A) in cancer cells and inhibits cell-cycle progression.

The INK4A locus encodes two tumor suppressor genes, p16(INK4A) and p14(ARF), transcribed using alternative exons 1alpha or 1beta spliced onto the same exons 2 and 3. Both p16(INK4A) and p14(ARF) are capable of inhibiting the cell-cycle progression, albeit in different manner; p16(INK4A) is phosphorylation of retinoblastoma (pRB) dependent while p14(ARF) is p53-dependent. In this study, we report the discovery of a novel variant of p16(INK4A), termed p16gamma, in a primary T-cell acute lymphoblastic leukemia (T-ALL) patient sample and a neuroblastoma cell line, which was expressed at both the transcriptional and translational levels. Cloning and sequencing of the p16gamma cDNA revealed that p16gamma was identical to p16(INK4A), except that it contained an in-frame insertion of 197 bp between exons 2 and 3. p16gamma expression was detected in the majority of p16(INK4A)-expressing primary T-ALL and B-ALL patient samples and other p16(INK4A)-expressing tumor samples, but was only barely detectable in some normal mononuclear cells and other non-tumor samples. Structural analysis by nuclear magnetic resonance and circular dichroism confirmed that p16gamma, like p16(INK4A), is also an ankyrin-repeat protein. Functional analysis of p16gamma revealed that p16gamma protein interacted with cyclin D-dependent kinase4 and inhibited its kinase activity. Using a luciferase reporter assay, the transfection of p16gamma repressed the E2F response, the downstream target of pRB, with an efficacy equivalent to that of p16(INK4A). Moreover p16gamma, like p16(INK4A), induced cell-cycle arrest at G(0)/G(1), and inhibited cell growth in colony formation assay.

Intussusception after gastric surgery.

Intussusception following gastric surgery is a rare postoperative complication. It may develop in clinical situations following gastroenterostomy, Billroth II gastric surgery with or without Braun anastomosis, or Roux-en-Y gastrojejunostomy. The patients may present with either an acute surgical emergency or with a chronic, relapsing form. The mortality may be up to 50 % in these cases if not treated appropriately, but little is known about the mechanism underlying the condition. Early diagnosis with a high index of suspicion and prompt treatment of the acute form are therefore important. Surgical reduction with laparotomy is mandatory, although definitive corrective and preventative measures have not yet been established.

Adult-to-adult living donor liver transplantation at the Asan Medical Center, Korea.

Between February 1997 and December 2001, 311 adult-to-adult living donor liver transplants (A-A LDLTs) were performed at the Asan Medical Center for patients above 20 years of age. Indications for A-A LDLT were: chronic hepatitis B (203), chronic hepatitis C (5), hepatocellular carcinoma (64), alcoholic cirrhosis (9), cryptogenic cirrhosis (4), secondary biliary cirrhosis (5), primary biliary cirrhosis (1), Wilson' s disease (2), autoimmune hepatitis (1), hepatic tuberculosis (1), cholangiocarcinoma (1), fulminant hepatic failure (14) and primary non-function of cadaveric liver graft (1). Of 311 A-A LDLTs, 36 were of medical high urgency, 20 were for acute and subacute hepatic failure, 15 were for hepato-renal syndrome and 1 was for primary non-function. Recipient age ranged from 27 to 64 years. Donor age ranged from 16 to 62 years. There was no donor mortality. Implanted liver grafts were categorized into seven types: 175 modified right lobe (MRL), 70 left lobe, 32 right lobe, 20 dual grafts, 10 left lobe plus caudate lobe, three extended right lobe and one posterior segment. In MRL, the tributaries of the middle hepatic vein were reconstructed by interpositioning a vein graft. Indication for dual graft implantation was the same as single graft A-A LDLT, and four of 20 were emergency cases. Of 20 dual grafts, 14 received two left lobes, four received a left lobe and a lateral segment, one received a right lobe and a left lobe and one received a lateral segment and a posterior segment. Graft volume ranged from 28% to 83% of the standard liver volume of the recipients. There were 33 (10.6%) in-hospital mortalities (< 4 months) among the 310 patients after 311 A-A LDLTs. Of the 36 patients receiving emergency transplants, 31 survived. These encouraging results justify the expansion of A-A LDLT in coping with increasing demands, even in urgent situations. We have aimed to introduce the establishment of the efficacy of A-A LDLT in various end-stage chronic and acute liver diseases, as well as new technical advances to overcome small graft-size syndrome by using dual-graft implantation and MRL, both of which were first developed in our department.

Ordered nanoporous arrays of carbon supporting high dispersions of platinum nanoparticles.

Nanostructured carbon materials are potentially of great technological interest for the development of electronic, catalytic and hydrogen-storage systems. Here we describe a general strategy for the synthesis of highly ordered, rigid arrays of nanoporous carbon having uniform but tunable diameters (typically 6 nanometres inside and 9 nanometres outside). These structures are formed by using ordered mesoporous silicas as templates, the removal of which leaves a partially ordered graphitic framework. The resulting material supports a high dispersion of platinum nanoparticles, exceeding that of other common microporous carbon materials (such as carbon black, charcoal and activated carbon fibres). The platinum cluster diameter can be controlled to below 3 nanometres, and the high dispersion of these metal clusters gives rise to promising electrocatalytic activity for oxygen reduction, which could prove to be practically relevant for fuel-cell technologies. These nanomaterials can also be prepared in the form of free-standing films by using ordered silica films as the templates.

The use of high-resolution computed tomography in the evaluation of pulmonary hemodynamics in patients with congenital heart disease: in pulmonary vessels larger than 1 mm in diameter.

High-resolution computed tomography (HRCT) was carried out in 36 patients with congenital left-to-right shunt disease and 10 normal control subjects to assess the feasibility of CT in the evaluation of pulmonary hemodynamics. The patients had a left-to-right or a bidirectional shunt and the hemodynamic data obtained by cardiac catheterization in these patients were compared to the information obtained by CT imaging. The pulmonary/systemic blood flow (Q(p)/Q(s)) ratio and pulmonic/systemic resistance (R(p)/R(s)) ratio had a significant correlation with the pulmonary artery/bronchus (PA/Br) ratio (r = 0.54 and r = -0.37, respectively) and pulmonary vein/bronchus (PV/Br) ratio (r = 0.66 and r = -0.66, respectively), and the R(p)/R(s) and mean PA pressure also showed a significant correlation with the PA/PV ratio (r = 0.53 and r = -0.61, respectively) in the mid-lung field when accompanying bronchi were 4. 0-5.9 mm in diameter. There was no correlation between the hemodynamic data and the size of the central and hilar PA or with the rate of PA tapering. With HRCT, it is possible to evaluate pulmonary hemodynamics in patients with congenital heart disease with a left-to-right or bidirectional shunt, particularly R(p)/R(s) and mean PA pressure, which have been very difficult to obtain noninvasively. The small-sized pulmonary vessel/Br ratio or the small-sized PA/PV ratio could offer very useful information, but the dimension of the central PA provided the least useful information.

CT findings of pulmonary tuberculosis presenting as segmental consolidation.

PURPOSE: The purpose of our study was to determine specific CT findings of tuberculous pneumonia presenting as segmental or lobar consolidation along with a pathologic review of specimens with similar radiographic patterns. METHOD: CT findings of 45 cases of proven tuberculous pneumonia and 21 proven nontuberculous pneumonia were compared. Pathologic findings of five surgically resected tuberculous pneumonia cases were also investigated. The presence of fluid bronchogram (linear, branching shadow of fluid attenuation) and inner low attenuation/cavitation in the area of consolidation, luminal dilatation, and wall thickening of proximal bronchi were the main points sought on CT scan. In addition, the presence of bronchogenic dissemination, lymph node enlargement, and pleural lesions was also checked for in the unaffected area of both lungs. RESULTS: The following bronchial changes were seen in the tuberculous pneumonia and nontuberculous pneumonia groups, respectively: fluid bronchogram in 68.9 and 23.8% (p < 0.05), bronchial luminal dilatation in 60.0 and 23.8% (p < 0.05), and bronchial wall thickening of the proximal airway leading to the area of consolidation in 52.8 and 7% (p < 0.05). Bronchogenic dissemination outside the consolidation appeared in 88.9 and 52.4% (p < 0.05), respectively. In the tuberculous pneumonia group, lymph node enlargement and pleural reaction were seen in 55.6 and 35.6%, respectively, but in 42.9 and 57.1% in the nontuberculous pneumonia group (p > 0.05). Histologically, tuberculous pneumonia showed either bronchioles containing inflammatory exudates and submucosal granuloma or alveoli containing aggregates of alveolar macrophages or cellular debris. CONCLUSION: Fluid bronchogram in the area of homogeneous consolidation, bronchial luminal dilatation, and bronchial wall thickening of the proximal airway were the bronchial changes more significantly prominent in the tuberculous pneumonia group. We suspect that these findings may represent tuberculous bronchitis in small airways.