Effects of electron-cyclotron-resonance-heating-induced internal kink mode on the toroidal rotation in the KSTAR Tokamak

It is observed that the magnitude of the toroidal rotation speed is reduced by the central electron cyclotron resonance heating (ECRH) regardless of the direction of the toroidal rotation. The magnetohydrodynamics activities generally appear with the rotation change due to ECRH. It is shown that the internal kink mode is induced by the central ECRH and breaks the toroidal symmetry. When the magnetohydrodynamics activities are present, the toroidal plasma viscosity is not negligible. The observed effects of ECRH on the toroidal plasma rotation are explained by the neoclassical toroidal viscosity in this Letter. It is found that the neoclassical toroidal viscosity torque caused by the internal kink mode damps the toroidal rotation.

Inversion technique to obtain local rotation velocity and ion temperature from line-integrated measurements for elongated tokamak plasma

An inversion technique is presented to calculate local toroidal and poloidal rotation velocity and ion temperature from line-integrated measurements of impurity lines by a matrix method. The effects of the rotation velocity on the ion temperature are analyzed in particular. An accurate inversion formula for the ion temperature is obtained. Several experimental geometries or configurations of line-integrated diagnostics in tokamaks are presented. For a plasma that is up-down symmetric, both the toroidal rotation velocity and poloidal rotation velocity can be deduced from one special line-integrated measurement.

Upgrades of the high resolution imaging x-ray crystal spectrometers on experimental advanced superconducting tokamak

Two imaging x-ray crystal spectrometers, the so-called "poloidal" and "tangential" spectrometers, were recently implemented on experimental advanced superconducting tokamak (EAST) to provide spatially and temporally resolved impurity ion temperature (T(i)), electron temperature (T(e)) and rotation velocity profiles. They are derived from Doppler width of W line for Ti, the intensity ratio of Li-like satellites to W line for Te, and Doppler shift of W line for rotation. Each spectrometer originally consisted of a spherically curved crystal and a two-dimensional multi-wire proportional counter (MWPC) detector. Both spectrometers have now been upgraded. The layout of the tangential spectrometer was modified, since it had to be moved to a different port, and the spectrometer was equipped with two high count rate Pilatus detectors (Model 100 K) to overcome the count rate limitation of the MWPC and to improve its time resolution. The poloidal spectrometer was equipped with two spherically bent crystals to record the spectra of He-like and H-like argon simultaneously and side by side on the original MWPC. These upgrades are described, and new results from the latest EAST experimental campaign are presented.

Tangential x-ray imaging crystal spectrometer on J-TEXT tokamak

A tangential x-ray imaging crystal spectrometer (XICS) has been developed for the J-TEXT tokamak to measure the ion temperature and the plasma toroidal rotation velocity. The resonance spectral line and its satellites of Ar XVII in the ranges of 3.94 Å-4.0 Å are detected. A spherically bent quartz crystal with 2d = 4.913 Å is used in this system. The crystal has a dimension of 9 cm high and 3 cm wide and the radius of curvature 3823 mm. The XICS is designed to receive emission of Ar XVII from -10 cm to +10 cm region with a spatial resolution of 3.1 cm in the vertical direction considering the parameters of the J-TEXT plasma. The XICS has a tangential angle of 27° with respect to toroidal direction in the magnetic axis. A two-dimensional 100 mm by 300 mm multi-wire proportional counter is applied to detect the spectra.

A novel fluorescent reporter system for monitoring and identifying RNase III activity and its target RNAs

Bacteriophage vectors for achieving single-copy gene expression linked to a colorigenic reporter assay have been used successfully for genetic screening applications. However, the limited number of cloning sites in these vectors, combined with the requirement for lac- strains and the time- and/or media-dependence of the chemical-based colorimetric reaction, have limited the range of applications for these vectors. An alternative approach using a fluorescent reporter gene such as green fluorescent protein (GFP) or GFP derivatives could overcome some of these technical issues and facilitate real-time monitoring of promoter and/or protein activity. Here, we report the development of a novel translational bacteriophage fusion vector encoding enhanced GFP (eGFP) that can be incorporated into the chromosome as a single-copy gene. We identified a Bacillus promoter (BP) that is stably expressed in Escherichia coli and drives ~6-fold more expression of eGFP than the T7 promoter in the absence of inducer. Incorporating this BP and RNase III target signals into a single system enabled clear detection of the absence or downregulation of RNase III activity in vivo, thereby establishing a system for screening and identifying novel RNase III targets in a matter of days. An RNase III target signal identified in this manner was confirmed by post-transcriptional analysis. We anticipate that this novel translational fusion vector will be used extensively to study activity of both interesting RNases and related complex or to identify or validate targets of RNases that are otherwise difficult to study due to their sensitivity to environmental stresses and/or autoregulatory processes.

Standardization of modified right lobe grafts to minimize vascular outflow complications for adult living donor liver transplantation

BACKGROUND

After >2000 adult living donor liver transplants (LDLTs), we observed minimization of the complication rate using case-by-case modification of venous outflow reconstruction in right liver graft (RLG), standardization seeking intend to provide a hemodynamic- based, regeneration-compliant hepatic outflow reconstruction.

METHODS

We retrospectively examined 100 consecutive adult LDLT using modified RLG before and after application of RLG standardization to compare the 6-month incidences of vascular outflow complications.

RESULT

The right hepatic vein stenting rate for first 6 months was 5% in the customized group and 1% in the standardized group (P=.212). The middle hepatic vein stenting rate for first 6 months was 9% in the customized group and 4% in the standardized group (P=.373). The inferior right hepatic vein stenting rate for first 6 months was 12.8% in the customized group and 7.1% in the standardized group (P=.472). The overall 6-month patient survival rate was 94% in the customized group and 95% in the standardized group (P=.867). The overall incidence of significant RLG venous outflow complications was 19% in the customized group and 8% in the standardized group (P=.023).

CONCLUSION

Standardization as a universal graft model seemed to be more effective and feasible than conventional graft customization requiring individualized case-by-case modification.

De novo malignancies after liver transplantation: incidence comparison with the Korean cancer registry

PURPOSE

De novo malignancy is not uncommon after liver transplantation (OLT). We have compared the incidence of novo malignancy following OLT with those among the general Korean population.

METHODS

Between January 1998 and December 2008, 1952 adult OLT were performed, including 1714 living donor and 238 deceased donor grafts whose medical records were retrospectively reviewed.

RESULTS

Among the 1952 patients, 44 (2.3%) showed de novo malignancies after a mean posttransplant period of 41 months. Among the 14 types of malignancy the most frequent was stomach cancer (n = 11; 25.0%), colorectal cancer (n = 9; 20.5%), breast cancer (n = 4; 9.1%), and thyroid cancer (n = 3; 6.8%). These patients underwent aggressive treatment, including surgery, chemotherapy, and radiotherapy, except for one patient with an aggressive primary liver cancer. Over a mean follow-up of 45 months after diagnosis of de novo malignancy, 13 patients (29.5%) died; the overall 3-year patient survival rate was 67.5%. The relative risk of malignancy following OLT was 7.7-fold higher in men and 7.3-fold higher in women than the Korean general population.

CONCLUSIONS

OLT recipients must be checked periodically for de novo malignancy throughout their lives, especially for cancers common in the general population.

Suppression of edge localized modes in high-confinement KSTAR plasmas by nonaxisymmetric magnetic perturbations

Edge localized modes (ELMs) in high-confinement mode plasmas were completely suppressed in KSTAR by applying n=1 nonaxisymmetric magnetic perturbations. Initially, the ELMs were intensified with a reduction of frequency, but completely suppressed later. The electron density had an initial 10% decrease followed by a gradual increase as ELMs were suppressed. Interesting phenomena such as a saturated evolution of edge T(e) and broadband changes of magnetic fluctuations were observed, suggesting the change of edge transport by the applied magnetic perturbations.

Quantitative analyses of individual sugars in mixture using FRET-based biosensors

Molecular biosensors were developed and applied to measure individual sugars in biological mixtures such as bacterial culture broths. As the sensing units, four sugar-binding proteins (SBPs for allose, arabinose, ribose, and glucose) were selected from the Escherichia coli genome and connected to a cyan fluorescent protein and yellow fluorescent protein via dipeptide linkers (CFP-L-SBP-YFP). The putative sensors were randomized in the linker region (L) and then investigated with regard to the intensity of fluorescence resonance energy transfer on the binding of the respective sugars. As a result, four representatives were selected from each library and examined for their specificity using 16 available sugars. The apparent dissociation constants of the allose, arabinose, ribose, and glucose sensors were estimated to be 0.35, 0.36, 0.17, and 0.18 μM. Finally, the sugar sensors were applied to monitor the consumption rate of individual sugars in an E. coli culture broth. The individual sugar profiles exhibited a good correlation with those obtained using an HPLC method, confirming that the biosensors offer a rapid and easy-to-use method for monitoring individual sugars in mixed compositions.

Mesh-integrated microdroplet array for simultaneous merging and storage of single-cell droplets

We constructed a mesh-grid integrated microwell array which enables easy trapping and consistent addition of droplets. The grid acts as a microchannel structure to guide droplets into the microwells underneath, and also provides open access for additional manipulation in a high-throughput manner. Each droplet in the array forms a stable environment of pico-litre volume to implement a single-cell-based assay.

Cloning of a Family 11 Xylanase Gene from Bacillus amyloliquefaciens CH51 Isolated from Cheonggukjang

Bacillus amyloliquefaciens CH51, an isolate from cheonggukjang, Korean fermented soyfood, secretes several enzymes into culture medium. A gene encoding 19 kDa xylanase was cloned by PCR. Sequencing showed that the gene encoded a glycohydrolase family 11 xylanase and named xynA. xynAHis, xynA with additional codons for his-tag, was overexpressed in Escherichia coli BL21(DE3) using pET-26b(+). XynAHis was purified using HisTrap affinity column. Km and Vmax of XynAHis were 0.363 mg/ml and 701.1 μmol/min/mg, respectively with birchwood xylan as a substrate. The optimum pH and temperature were pH 4 and 25 °C, respectively. When xynA was introduced into Bacillus subtilis WB600, active XynA was secreted into culture medium.

Role of Junctin protein interactions in cellular dynamics of calsequestrin polymer upon calcium perturbation

Calsequestrin (CSQ), the major intrasarcoplasmic reticulum calcium storage protein, undergoes dynamic polymerization and depolymerization in a Ca(2+)-dependent manner. However, no direct evidence of CSQ depolymerization in vivo with physiological relevance has been obtained. In the present study, live cell imaging analysis facilitated characterization of the in vivo dynamics of the macromolecular CSQ structure. CSQ2 appeared as speckles in the presence of normal sarcoplasmic reticulum (SR) Ca(2+) that were decondensed upon Ca(2+) depletion. Moreover, CSQ2 decondensation occurred only in the stoichiometric presence of junctin (JNT). When expressed alone, CSQ2 speckles remained unchanged, even after Ca(2+) depletion. FRET analysis revealed constant interactions between CSQ2 and JNT, regardless of the SR Ca(2+) concentration, implying that JNT is an essential component of the CSQ scaffold. In vitro solubility assay, electron microscopy, and atomic force microscopy studies using purified recombinant proteins confirmed Ca(2+) and JNT-dependent disassembly of the CSQ2 polymer. Accordingly, we conclude that reversible polymerization and depolymerization of CSQ are critical in SR Ca(2+) homeostasis.

Effect of splenic artery embolization for splenic artery steal syndrome in liver transplant recipients: estimation at computed tomography based on changes in caliber of related arteries

PURPOSE

To estimate the effect of splenic artery embolization (SAE) on blood flow in orthotopic liver transplantation (OLT) recipients with splenic artery steal syndrome (SASS) based on changes in caliber of related arteries upon serial computed tomography (CT) scans.

METHODS

Between 2004 and 2007, nine OLT recipients with SASS underwent SAE. They had CT scans before and after SAE: short-, mid-, and long-term, ie, approximately 1 week, 1 month, and 1 year, respectively. The diameters of the celiac axis (CA), common hepatic artery (CHA), and splenic artery (SA) were measured with arterial phase of each CT scan and the ratios of SA to CHA diameter (SA/CHA) calculated to analyze their changes during the follow-up period.

RESULTS

The diameters of celiac axis, CHA, and SA and SA/CHA changed most rapidly during the short-term period. The CHA diameter significantly increased short-term post-SAE by CT and slightly decreased thereafter. However, the mid-term and long-term post-SAE CT values were still significantly greater than those on the pre-SAE CT. The SA diameter steadily decreased throughout the follow-up. The SA/CHA decreased until the mid-term. The SA diameter and SA/CHA were significantly smaller upon mid-term and long-term post-SAE CT compared with those at pre-SAE CT.

CONCLUSIONS

The effect of SAE to improve hepatic arterial flow in OLT recipients with SASS might be expected for at least approximately one year. The effect maximally occurred during the short-term after SAE on the basis of changes in the caliber of related arteries upon CT.

Development of fluorescent probes for the detection of fucosylated N-glycans using an Aspergillus oryzae lectin

The α(1,6)-fucose attached to the core N-glycan (core fucose) of glycoproteins has been known to play essential roles in various pathophysiological events, including oncogenesis and metastasis. Aspergillus oryzae lectin (AOL) encoded by the fleA gene has been reported to bind to N-glycans containing core fucose. The fleA gene encoding AOL was cloned into an Escherichia coli expression vector and then fused with genes of fluorescent proteins for production of fusion proteins. The resulting FleA-fluorescent fusion proteins were expressed well in E. coli and shown to detect glycoproteins containing N-glycans with core fucose by lectin blot assay. It was also shown to bind to the surface of cancer cells highly expressing the fucosyltransferase VIII for attachment of core fucose. Surprisingly, we found that FleA-fluorescent fusion proteins could be internalized into the intracellular compartment, early endosome, when applied to live cells. This internalization was shown to occur through a clathrin-mediated pathway by endocytosis inhibitor assay. Taken together, these results suggest that FleA-fluorescent fusion proteins can be employed as a valuable fluorescent probe for the detection of fucosylated glycans and/or a useful vehicle for delivery of substances to the inside of cells.

Comparison of open and laparoscopic live donor left lateral sectionectomy

BACKGROUND

The present study was undertaken to determine whether laparoscopic live donor left lateral sectionectomy (LLS) in paediatric liver transplantation is a feasible, safe and reproducible procedure, compared with open live donor left lateral sectionectomy (OLS).

METHODS

A retrospective review was conducted of all consecutive live donor procedures for paediatric liver transplantation performed between May 2008 and October 2009. All live donor hepatectomies were carried out by a single surgeon.

RESULTS

A total of 26 live donor procedures for paediatric liver transplantation were performed, of which 11 were LLS and 11 OLS; four left hepatectomies were excluded. The LLS group had a significantly shorter hospital stay (mean(s.d.) 6·9(0·3) versus 9·8(0·9) days; P = 0·001) and time to oral diet (2·1(0·3) versus 2·7(0·4) days; P = 0·012). Duration of operation, blood loss, warm ischaemia time and out-of-pocket medical costs were comparable between groups. There was no death in either donor group and only one complication, a wound seroma, in the OLS group.

CONCLUSION

LLS seemed to be a safe, feasible and reproducible procedure, and was associated with reduced hospital stay.

Diamagnetic loop measurement in Korea Superconducting Tokamak Advanced Research machine

Diamagnetic loop (DL), which consists of two poloidal loops inside the vacuum vessel, is used to measure the diamagnetic flux during a plasma discharge in the Korea Superconducting Tokamak Advanced Research (KSTAR) machine. The vacuum fluxes in the DL signal can be compensated up to 0.1 mWb by using the coefficients, which are obtained from experimental investigations, in the vacuum flux measurements during vacuum shots under same operational conditions of magnetic coils for plasma experiment in the KSTAR machine. The maximum error in the diamagnetic flux measurement due to the errors of the coefficients was estimated as ∼0.22 mWb. From the diamagnetic flux measurements for the ohmically heated circular plasmas in the KSTAR machine, the stored energy agrees well with the estimated kinetic energy within the discrepancy of 25%. When the electron cyclotron heating, the neutral beam injection, and the ion cyclotron resonance heating are added to the ohmically heated limiter plasmas, the additional heating effects can be clearly observed from the increase of the stored energy evaluated in the DL measurement.

Peritransplant monitoring of immune cell function in adult living donor liver transplantation

PURPOSE

We evaluated the clinical utility of peritransplant in vitro assays of immune cell function in adult living donor liver transplant (LDLT) recipients.

METHODS

In particular, we measured immune cell function, using the ImmuKnow assay, in 107 adult LDLT recipients and 200 potential living liver donors (control group) admitted to our center between July 2008 and January 2009.

RESULTS

In the control group, the mean proportion of T-helper/inducer cells was 36.8% ± 8.2%. The degree of immune response was strong in 12%, moderate in 77%, and low in 11%. In the study group, the degree of immune response within the first month was strong in 4.6%, moderate in 38.2%, and low in 57.2%, thus significantly lower than in the control group (P < .001). ImmuKnow results and tacrolimus levels did not show a significant correlation (r(2) = .002, P = .392). Although six patients showed biopsy-proven acute cellular rejection, none showed a strong immune response. Patients with overt infection showed a lower immune response.

CONCLUSIONS

These results indicate that peritransplant assessment of immune response using the ImmuKnow assay does not reliably predict the occurrence of acute rejection. Additional studies are necessary to accurately assess the clinical utility of immune response monitoring.

Comparison of the molecular adsorbent recirculating system and plasmapheresis for patients with graft dysfunction after liver transplantation

BACKGROUND

Graft dysfunction after liver transplantation (OLT) is a life- threatening condition. Molecular adsorbent recirculating system (MARS) or plasmapheresis (PLP) may be effective supportive therapy of graft dysfunction for patients who cannot undergo retransplantation. The aim of this study was to compare the effects of MARS and PLP in patients with graft dysfunction after OLT.

METHODS

Between January 2002 and July 2007, 31 OLT recipients who experienced graft dysfunction, defined as hyperbilirubinemia (>10 mg/dL) without bile duct obstruction and/or presence of hepatic encephalopathy, were treated with MARS or PLP. Biochemical and hemodynamic data and survival were compared in MARS and PLP groups.

RESULTS

Fifteen patients were treated with 41 MARS sessions and 16 with 105 PLP sessions. After a single MARS session, patients showed significant reductions in creatinine, urea nitrogen, bilirubin, and ammonia. After a single PLP session, patients showed significant improvements in prothrombin time, bilirubin, alanine aminotransferase, alkaline phosphatase, and albumin. After the completion of treatment, Both MARS and PLP significantly improved bilirubin values. at 90 days there were no differences in overall survival rates; 53% in MARS versus 56% in PLP.

CONCLUSION

Both MARS and PLP are alternative supportive treatments for graft dysfunction after OLT.

Development of a spatially resolving x-ray crystal spectrometer for measurement of ion-temperature (T(i)) and rotation-velocity (v) profiles in ITER

Imaging x-ray crystal spectrometer (XCS) arrays are being developed as a US-ITER activity for Doppler measurement of T(i) and v profiles of impurities (W, Kr, and Fe) with ∼7 cm (a/30) and 10-100 ms resolution in ITER. The imaging XCS, modeled after a prototype instrument on Alcator C-Mod, uses a spherically bent crystal and 2D x-ray detectors to achieve high spectral resolving power (E/dE>6000) horizontally and spatial imaging vertically. Two arrays will measure T(i) and both poloidal and toroidal rotation velocity profiles. The measurement of many spatial chords permits tomographic inversion for the inference of local parameters. The instrument design, predictions of performance, and results from C-Mod are presented.