Performance and data analysis aspects of the new DIII-D monostatic profile reflectometer system

A new frequency-modulated profile reflectometer system, featuring a monostatic antenna geometry (using one microwave antenna for both launch and receive), has been installed on the DIII-D tokamak, providing a first experimental test of this measurement approach for profile reflectometry. Significant features of the new system are briefly described in this paper, including the new monostatic arrangement, use of overmoded, broadband transmission waveguide, and dual-polarization combination/demultiplexing. Updated data processing and analysis, and in-service performance aspects of the new monostatic profile reflectometer system are also presented. By using a raytracing code (GENRAY) to determine the approximate trajectory of the probe beam, the electron density (ne) profile can be successfully reconstructed with L-mode plasmas vertically shifted by more than 10 cm off the vessel midplane. Specifically, it is demonstrated that the new system has a capability to measure ne profiles with plasma vertical offsets of up to ±17 cm. Examples are also presented of accurate, high time and spatial resolution density profile measurements made over a wide range of DIII-D conditions, e.g., the measured temporal evolution of the density profile across a L-H transition.

Optical layout and mechanical structure of polarimeter-interferometer system for Experimental Advanced Superconducting Tokamak

A Far-InfaRed (FIR) three-wave POlarimeter-INTerferometer (POINT) system for measurement current density profile and electron density profile is under development for the EAST tokamak. The FIR beams are transmitted from the laser room to the optical tower adjacent to EAST via ∼20 m overmoded dielectric waveguide and then divided into 5 horizontal chords. The optical arrangement was designed using ZEMAX, which provides information on the beam spot size and energy distribution throughout the optical system. ZEMAX calculations used to optimize the optical layout design are combined with the mechanical design from CATIA, providing a 3D visualization of the entire POINT system.

Faraday-effect polarimeter-interferometer system for current density measurement on EAST

A multichannel far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique is under development for current density and electron density profile measurements in the EAST tokamak. Novel molybdenum retro-reflectors are mounted in the inside wall for the double-pass optical arrangement. A Digital Phase Detector with 250 kHz bandwidth, which will provide real-time Faraday rotation angle and density phase shift output, have been developed for use on the POINT system. Initial calibration indicates the electron line-integrated density resolution is less than 5 × 10(16) m(-2) (∼2°), and the Faraday rotation angle rms phase noise is <0.1°.

Using neutral beams as a light ion beam probe (invited)

By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of (1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge and (2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fields appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g., Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally imposed 3D fields, e.g., magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. In addition, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.

β-Catenin is required for maintaining hippocampal morphology during the perinatal period

In mice, the compact hippocampal primordium is formed during the prenatal stage by early-generated neurons that migrate from the lateral ventricular zone. However, despite much being understood about the formation of the hippocampus, the molecular mechanisms that maintain the morphology of the hippocampal primordium after its formation remain to be characterized. β-Catenin is a key factor of canonical Wnt signaling and also a component of adherens junctions. Previous embryonic deletion studies have demonstrated that β-catenin is required for early development and generation of granule cells. However, whether β-catenin is involved in the morphological maintenance of the hippocampus as a cell adhesion molecule is still unknown. Here, we report that perinatal deletion of β-catenin in postmitotic neurons and some radial glial cells of hippocampus using CamKIIα-iCre; β-cateninflox/flox conditional knockout mice, leads to disorganization of the radial glial scaffold and consequentially severe defects in hippocampal morphology. We demonstrate that β-catenin is required for maintaining radial glial scaffold possibly via its well-known role in cell adhesion during the perinatal period. These findings provide essential advances into our understanding of the maintenance of the hippocampal primordium during the perinatal period.

Identification of 32 major histocompatibility complex class I alleles in African green monkeys

The African green monkey may be an ideal replacement for the rhesus monkey in biomedical research, but relatively little is known about the genetic background of major histocompatibility complex (MHC) class I molecules. In analysis of 12 African green monkeys, 13 Chae-A and 19 Chae-B alleles were identified. Among these alleles, 12 Chae-A and 9 Chae-B were new lineages. The full amino acid length deduced for Chae-A genes is 365 amino acids, but for Chae-B genes, the lengths are 365, 362, 361, and 359 amino acids, respectively. There were 1-3 Chae-A alleles and 2-5 Chae-B alleles in each animal. In African green monkeys, rhesus monkeys, and cynomolgus monkeys, the MHC-A and MHC-B alleles display trans-species polymorphism, rather than being clustered in a species-specific fashion.

Seven novel MHC class I alleles identified in Cercopithecus mitis

We report here the identification of three Cemi-A and four Cemi-B novel alleles of Cercopithecus mitis.

Evidence for Borna disease virus infection in neuropsychiatric patients in three western China provinces

Borna disease virus (BDV) is a non-cytolytic, neurotropic RNA virus that can infect a wide variety of vertebrate species from birds and primates to humans. Several studies have been carried out to investigate whether BDV is associated with neuropsychiatric diseases. However, this association is still inconclusive. Two panels of subjects consisting of 1,679 various neuropsychiatric patients and healthy people from three western China provinces were enrolled in this study. BDV p24 or p40 RNA in peripheral blood mononuclear cells (PBMCs) were detected in the first panel of 1,481 subjects using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and cerebrospinal fluid (CSF) samples from the BDV RNA-positive individuals were subjected to BDV p24 antibodies testing by enzyme-linked immunosorbent assay (ELISA). BDV p24 or p40 RNA in PBMCs and p24 antibodies in plasma were detected in the second panel of 198 subjects by RT-qPCR and Western blot. A higher prevalence for BDV RNA was demonstrated in patients with viral encephalitis (6.70%), Guillain-Barré syndrome (6.70%), schizophrenia (9.90%) and chronic fatigue syndrome (CFS) (12.70%) compared to healthy controls in the first panel. CSF p24 antibodies were demonstrated in three viral encephalitis patients, two schizophrenia patients and two major depressive disorder (MDD) patients. The prevalences of p24 antibodies in plasma from patients with viral encephalitis (13.24%), multiple sclerosis (25.00%) and Parkinson's disease (22.73%) were significantly higher than healthy controls. This study demonstrates that BDV infection also exists in humans from three western China provinces, and suggests the involvement of the contribution of BDV in the aetiology of Chinese patients with some neuropsychiatric disorders, including viral encephalitis, schizophrenia, CFS, multiple sclerosis and Parkinson's disease.

Hyperglycaemia-induced chemoresistance of prostate cancer cells due to IGFBP2

Clinically relevant prostate cancer (PCa) is more frequent in Westernised societies and increasingly men have co-morbidities associated with a Western lifestyle, primarily diabetes, characterised by hyperinsulinaemia and hyperglycaemia. IGFs and their binding proteins (IGFBPs) are important mediators of the effects of nutrition on growth and play a key role in the development of PCa. We used DU145, PC3 and LNCaP PCa cell lines to examine how hyperglycaemia altered their response to docetaxel. Trypan Blue dye-exclusion assay was used to determine the percentage of cell death. Protein abundance was determined using western immunoblotting. Levels of IGFBP2 were measured using an ELISA. IGFBP2 gene silencing was achieved using siRNA technology. DNA methylation was assessed using combined bisulphide restriction analysis. Acetylation status of histones H3 and H4 associated with IGFBP2 gene was assessed using chromatin immunoprecipitation assay. Hyperglycaemia reduced docetaxel-induced apoptosis by 40% for DU145 cells and by 88% for LNCaP cells. This reduced cell death was mediated by a glucose-induced up-regulation of IGFBP2, as silencing IGFBP2 negated the survival effect of high glucose. Glucose increased IGFBP2 via increasing the acetylation of histones associated with the IGFBP2 gene promoter. This finding could have important implications in relation to therapeutic strategies as epigenetic modulation could be reversible.

Nucleotide receptor P2RX7 stimulation enhances LPS-induced interferon-β production in murine macrophages

Stimulation of P2RX(7) with extracellular ATP potentiates numerous LPS-induced proinflammatory events, including cytokine induction in macrophages, but the molecular mechanisms underlying this process are not well defined. Although P2RX(7) ligation has been proposed to activate several transcription factors, many of the LPS-induced mediators affected by P2RX(7) activation are not induced by P2RX(7) agonists alone, suggesting a complementary role for P2RX(7) in transcriptional regulation. Type I IFN production, whose expression is tightly controlled by multiple transcription factors that form an enhanceosome, is critical for resistance against LPS-containing bacteria. The effect of purinergic receptor signaling on LPS-dependent type I IFN is unknown and would be of great relevance to a diverse array of inflammatory conditions. The present study demonstrates that stimulation of macrophages with P2RX(7) agonists substantially enhances LPS-induced IFN-β expression, and this enhancement is ablated in macrophages that do not express functional P2RX(7) or when the MAPK MEK1/2 pathways are inhibited. Potentiation of LPS-induced IFN-β expression following P2RX(7) stimulation is likely transcriptionally regulated, as this enhancement is observed at the IFN-β promoter level. Furthermore, P2RX(7) stimulation is able to increase the phosphorylation and subsequent IFN-β promoter occupancy of IRF-3, a transcription factor that is critical for IFN-β transcription by TLR agonists. This newly discovered role for P2RX(7) in IFN regulation may have implications in antimicrobial defense, which has been linked to P2RX(7) activation in other studies.

Establishment, characterization and viral susceptibility of two cell lines derived from leopard wrasse Macropharyngodon geoffroy

Two new fish cell lines were established from skin (LWSK) and fin (LWFN) of leopard wrasse Macropharyngodon geoffroy. These cells grew optimally at 25° C in Leibovitz-15 medium supplemented with 10% foetal bovine serum. Proliferation of M. geoffroy cells remained serum dependent up to cell passage 16, and cell-plating efficiency ranged from 12 to 16%. Karyotypic analysis of these new cell lines at cell passage 8 indicated that both cell lines remained diploid with a peak chromosomal count of 144. PCR amplification of 16S mitochondrial DNA and the subsequent analysis confirmed that these cell lines were indeed derived from M. geoffroy. Results of viral challenge assays revealed that both LWSK and LWFN shared patterns of viral susceptibility similar to that of six fish viruses tested: LWSK and LWFN cells were highly permissive to channel catfish virus, spring viremia carp virus and snakehead rhabdovirus with high-yield virus production ranging from 10(7·18±0·17) to 10(8·37±0·16) TCID50  ml(-1) (mean ± s.d.). These newly established cell lines would be useful in attempts to isolate and study aquatic viruses, particularly the viral aetiology of green turtle fibropapilloma as M. geoffroy is known to be one of the common cleaner fish of green sea turtles.

Bone marrow-derived endothelial progenitor cells promote hematopoietic reconstitution after hematopoietic stem cell transplantation

OBJECTIVE

A hematopoietic deficit is a serious complication after hematopoietic stem cell transplantation. It has been shown that fetal blood-derived endothelial progenitor cells (EPCs) can promote hematopoietic reconstitution after transplantation. This study investigated whether EPCs from bone marrow (BM) of adult mice could promote hematopoietic reconstitution.

METHODS

Lethally irradiated BALB/c mice were administered BM cells or BM cells plus EPCs.

RESULTS

The results showed that EPC-treated mice displayed accelerated recovery of peripheral blood white blood cells and reticulocytes. But the platelets were not significantly different with versus without EPCs. Accelerated recovery of BM sinusoidal vessels, promotion of stem cell implantation, and decreased adipocyte formation were associated with the mechanism. Systemic administration of anti-vascular endothelial cadherin antibody neutralized these effects significantly.

CONCLUSION

These data showed that BM-derived EPC infusions augmented hematopoiesis suggesting a new approach to promote hematopoiesis.

A rotating directional probe for the measurements of fast ion losses and plasma rotation at Tokamak Experiment for Technology Oriented Research

This work discusses a new directional probe designed for measurements of fast ion losses and the plasma rotation with a high angular resolution in magnetically confined plasmas. Directional and especially Mach probes are commonly used diagnostics for plasma flow measurements, and their applicability for the fast ion losses detection has been demonstrated. A limitation of static Mach probes is their low angular resolution. At the Tokamak Experiment for Technology Oriented Research, the angular resolution is strongly restricted by the finite number of available measurement channels. In a dynamic plasma, where instabilities can lead to local changes of the field line pitch-angle, plasma flow, or fast ion losses, a low angular resolution makes a precise data analysis difficult and reduces the quality of the measured data. The new probe design, the rotating directional probe, combines the features of early directional probes and Mach probes. It consists of two radially aligned arrays of nine Langmuir probe pins with each array facing opposite directions. During the measurement the probe head rotates along its axis to measure the ion saturation current from all directions. As a result, the rotating directional probe simultaneously provides an angular dependent plasma flow and fast ion losses measurement at different radial positions. Based on the angular dependent data, a precise determination of the current density is made. In addition, the simultaneous measurement of the ion saturation current at different radial positions allows for resolving radially varying field line pitch-angles and identifying the radial dynamic of processes like fast ion losses.

The GSTP1 A1578G polymorphism and the risk of childhood acute lymphoblastic leukemia: results from an updated meta-analysis

Studies investigating the association between the glutathione S-transferase P1 (GSTP1) A1578G polymorphism and the risk of childhood acute lymphoblastic leukemia (ALL) report conflicting results. The aim of this study was to quantitatively summarize the evidence for such a relationship. Two investigators independently searched the Medline, Embase, China National Knowledge Infrastructure, and Wangfang databases for studies of the polymorphism and ALL. Summary odds ratios (ORs) and 95% confidence intervals (CIs) for the GSTP1 polymorphism and childhood ALL were calculated in a fixed-effect model. Pooled ORs were calculated for a co-dominant model (GG vs AA, AG vs AA), a dominant model (GG + AG vs AA), and a recessive model (GG vs AA + AG). Analyses were also performed in subgroups stratified by race, study design, genotyping methods, and study sample size. This meta-analysis included 8 case-control studies with 1384 childhood ALL cases and 1755 controls. Overall, the variant genotypes (GG and AG) of A1578G were not associated with childhood ALL risk, when compared with the wild-type homozygote AA genotype (GG vs AA, OR = 1.09, 95%CI = 0.84-1.43; AG vs AA, OR = 1.05, 95%CI = 0.91-1.23). Similarly, no associations were found in the dominant and recessive models (dominant model, OR = 1.06, 95%CI = 0.92-1.23; recessive model, OR = 1.09, 95%CI = 0.84-1.43). Stratified analyses did not detect significant association in any subgroup. No heterogeneity or publication bias was observed in the present study. This updated meta-analysis indicates that the GSTP1 A1578G polymorphism is not associated with the risk of childhood ALL. In the future, additional studies in Asian and African-American patients should be performed to re-evaluate the association in these populations.

Muscle cell-derived factors inhibit inflammatory stimuli-induced damage in hMSC-derived chondrocytes

OBJECTIVE

Pro-inflammatory cytokines play an important role in inducing cartilage degradation during osteoarthritis pathogenesis. Muscle is a tissue that lies near cartilage in situ. However, muscle's non-loading biochemical effect on cartilage has been largely unexplored. Here, we tested the hypothesis that muscle cells can regulate the response to pro-inflammatory cytokine-mediated damage in chondrocytes derived from human bone marrow-derived mesenchymal stem cells (hMSCs).

METHOD

hMSCs were allowed to undergo chondrogenic differentiation in porous silk scaffolds in the typical chondrogenic medium for 12 days. For the next 9 days, the cells were cultured in chondrogenic medium containing 50% conditioned medium derived from C2C12 muscle cells or fibroblast control cells, and were subject to treatments of pro-inflammatory cytokines IL-1β or TNFα.

RESULTS

Both IL-1β and TNFα-induced strong expression of multiple MMPs and hypertrophic markers Runx2 and type X collagen. Strikingly, culturing hMSC-derived chondrocytes in C2C12 muscle cell-conditioned medium strongly inhibited the expression of all these genes, a result further confirmed by GAG content and histological evaluation of matrix protein. To determine whether these effects were due to altered chondrocyte growth and survival, we assayed the expression of cell proliferation marker Ki67, cell cycle arrest markers p21 and p53, and apoptosis marker caspase 3. Muscle cell-conditioned medium promoted proliferation and inhibited apoptosis, thereby suggesting a possible decrease in the cellular aging and death that typically accompanies cartilage inflammation.

CONCLUSION

Our findings suggest the role of muscle in cartilage homeostasis and provide insight into designing strategies for promoting resistance to pro-inflammatory cytokines in hMSC-derived chondrocytes.

Experimental observation of a magnetic-turbulence threshold for runaway-electron generation in the TEXTOR tokamak

Magnetic turbulence is observed at the beginning of the current quench in intended TEXTOR disruptions. Runaway electron (RE) suppression has been experimentally found at magnetic turbulence larger than a certain threshold. Below this threshold, the generated RE current is inversely proportional to the level of magnetic turbulence. The magnetic turbulence originates from the background plasma and the amplitude depends strongly on the toroidal magnetic field and plasma electron density. These results explain the previously found toroidal field threshold for RE generation and have to be considered in predictions for RE generation in ITER.

Magnetic topology changes induced by lower hybrid waves and their profound effect on edge-localized modes in the EAST tokamak

Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.

Incidence of skeletal-related events over time from solid tumour bone metastases reported in randomised trials using bone-modifying agents

AIMS

Skeletal-related events (SREs) in patients with bone metastases decrease a patient's quality of life and functional status. Although bone-modifying agents have been found to reduce the time to first on-trial SRE and decrease the total incidence of SREs in randomised clinical trials, standard practice in the management of bone metastases has changed concurrently. The purpose of this study was to investigate if advances in bone-targeted therapies have decreased the incidence of individual types of SREs and to delineate the trend of SREs.

MATERIALS AND METHODS

A literature review was conducted in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials to identify phase III, randomised bisphosphonate and other bone-targeted therapy trials from 1980 to September 2011. For all studies, a mean year of enrolment ([start of enrolment + end of enrolment]/2) was calculated. The incidences of SREs were tabulated and expressed as percentages of on-trial patients. Generalised linear mixed models were used to search for the trends of SREs over time for all placebo and intervention arms. Regression coefficients were interpreted as the odds ratio, which was calculated using the exponential of the slope. Ninety-five per cent confidence intervals were also calculated.

RESULTS

In total, 20 eligible studies were identified that reported SRE data from phase III trials, of which 11 were suitable for the quantitative analysis. Most of the articles included patients with breast cancer and the remaining involved patients with prostate, renal cell, bladder and lung cancer or other solid tumours. Enrolment periods for all included data ranged from 1990 to 2009. Statistically significant overall downward trends in pathological fractures and the need for surgery were seen over time. Also significant differences between intervention and placebo were seen with all SREs.

CONCLUSION

The decrease in SREs over time may not only be a result of the development of new generation bone-targeted agents, but also due to better systemic management and awareness of events associated with bone metastases.

Progress dissecting the oral microbiome in caries and health

Recent rapid advances in "-omics" technologies have yielded new insights into the interaction of the oral microbiome with its host. Associations of species that are usually considered to be acid-tolerant with caries have been confirmed, while some recognized as health-associated are often present in greater proportions in the absence of caries. In addition, some newly identified bacteria have been suggested as potential contributors to the caries process. In spite of this progress, two major challenges remain. The first is that there is a great deal of heterogeneity in the phenotypic capabilities of individual species of oral bacteria. The second is that the most abundant taxa in oral biofilms display remarkable phenotypic plasticity, i.e., the bacteria associated most strongly with health or with caries can morph rapidly in response to alterations in environmental pH, carbohydrate availability and source, and oxygen tension and redox environment. However, new technologic advances coupled with "old-fashioned microbiology" are starting to erode the barriers to a more complete understanding of oral biofilm physiology and ecology, and in doing so are beginning to provide insights for the creation of novel cost-effective caries control therapies.

A galactose-specific sugar: phosphotransferase permease is prevalent in the non-core genome of Streptococcus mutans

Three genes predicted to encode the A, B and C domains of a sugar : phosphotransferase system (PTS) permease specific for galactose\(EII(Gal) ) were identified in the genomes of 35 of 57 recently sequenced isolates of Streptococcus mutans, the primary etiological agent of human dental caries. Mutants defective in the EII(Gal) complex were constructed in six of the isolates and showed markedly reduced growth rates on galactose-based medium relative to the parental strains. An EII(Gal) -deficient strain constructed using the invasive serotype f strain OMZ175 (OMZ/IIGal) expressed significantly lower PTS activity when galactose was present as the substrate. Galactose was shown to be an effective inducer of catabolite repression in OMZ175, but not in the EII(Gal) -deficient strain. In a mixed-species competition assay with galactose as the sole carbohydrate source, OMZ/IIGal was less effective than the parental strain at competing with the oral commensal bacterium Streptococcus gordonii, which has a high-affinity galactose transporter. Hence, a significant proportion of S. mutans strains encode a galactose PTS permease that could enhance the ability of these isolates to compete more effectively with commensal streptococci for galactose in salivary constituents and the diet.

Observation of a critical gradient threshold for electron temperature fluctuations in the DIII-D Tokamak

A critical gradient threshold has been observed for the first time in a systematic, controlled experiment for a locally measured turbulent quantity in the core of a confined high-temperature plasma. In an experiment in the DIII-D tokamak where L(T(e))(-1) = |∇T(e)|/T(e) and toroidal rotation were varied, long wavelength (k(θ)ρ(s) ≲ 0.4) electron temperature fluctuations exhibit a threshold in L(T(e))(-1): below, they change little; above, they steadily increase. The increase in δT(e)/T(e) is concurrent with increased electron heat flux and transport stiffness. Observations were insensitive to rotation. Accumulated evidence strongly enforces the identification of the experimentally observed threshold with ∇T(e)-driven trapped electron mode turbulence.

The added challenges of bone metastases treatment in elderly patients

Most cancers occur in those older than the age of 65 years. As the population of the world ages and life expectancies continue to increase, it is important to address treatment challenges for elderly patients. This narrative review details the challenges of palliative radiotherapy treatment for elderly patients with bone metastases. We begin with the definition of elderly and its appropriateness, outlining recent demographic data of patients with cancer. The current status of elderly participation in clinical trials is discussed by reviewing the recent literature and clinical trial data. Factors affecting enrolment of the elderly are assessed, with a focus on palliative radiotherapy trials, and what we can do to improve accrual in this data-driven setting. At present, there is a lack of level 1 evidence that evaluates the optimal treatment for elderly patients with bone metastases. Therefore, a review of safety and efficacy is given based on previously published reports. Palliative radiotherapy for elderly patients is a worthwhile treatment and should be recommended regardless of age, as supported by available evidence. Patient, family and physician concerns about physical burden may be reduced as single treatments (that often can be done in a single visit) are as beneficial as multiple treatments for painful bone metastases. In elderly patients, radiotherapy may even be the best treatment for these cases as opioid-related adverse events are amplified in this group and often dosages are more difficult to titrate. Clinicians should continue to encourage the enrolment of elderly patients on to clinical trials as these data form the basis of optimal treatment guidelines. Radiation oncologists are encouraged to reduce the physical burden for elderly patients by offering single treatments where appropriate and completing consultation, treatment simulation and treatment in a single clinical visit.

Design of a millimeter-wave polarimeter for NSTX-Upgrade and initial test on DIII-D

Polarimetry is a powerful diagnostic technique to probe plasma equilibria and magnetic fluctuations in fusion plasmas. In a high beta plasma such as the National Spherical Torus eXperiment (NSTX), these measurements are important to understand plasma stability and anomalous transport. A 288 GHz polarimeter operating along a major radial chord in retroreflection geometry has been developed and is being tested on the DIII-D tokamak to prepare for future implementation on NSTX-Upgrade. The system launches a rotating linearly polarized beam and detects the phase shift directly related to the polarization change caused by the plasma. To accomplish this, a pair of orthogonal linearly polarized beams with a stable difference frequency is generated using a single sideband modulation technique, then combined and transformed to be counter-rotating circularly polarized. To improve phase resolution, quasi-optical isolation, using Faraday rotators and polarizers, is utilized to eliminate a multi-path feedback effect, which is found to be the primary source of phase error. The bench tests in the laboratory and DIII-D power supply test discharges indicate ≤1° phase resolution.

Inter-rater reliability between musculoskeletal radiologists and orthopedic surgeons on computed tomography imaging features of spinal metastases

INTRODUCTION

The primary objective of this pilot study was to examine the inter-rater reliability in scoring the computed tomography (ct) imaging features of spinal metastases in patients referred for radiotherapy (rt) for bone pain.

METHODS

In a retrospective review, 3 musculoskeletal radiologists and 2 orthopedic spinal surgeons independently evaluated ct imaging features for 41 patients with spinal metastases treated with rt in an outpatient radiation clinic from January 2007 to October 2008. The evaluation used spinal assessment criteria that had been developed in-house, with reference to osseous and soft tissue tumour extent,presence of a pathologic fracture,severity of vertebral height loss, andpresence of kyphosis.The Cohen kappa coefficient between the two specialties was calculated.

RESULTS

Mean patient age was 69.2 years (30 men, 11 women). The mean total daily oral morphine equivalent was 73.4 mg. Treatment dose-fractionation schedules included 8 Gy/1 (n = 28), 20 Gy/5 (n = 12), and 20 Gy/8 (n = 1). Areas of moderate agreement in identifying the ct imaging appearance of spinal metastasis included extent of vertebral body involvement (κ = 0.48) and soft-tissue component (κ = 0.59). Areas of fair agreement included extent of pedicle involvement (κ = 0.28), extent of lamina involvement (κ = 0.35), and presence of pathologic fracture (κ = 0.20). Areas of poor agreement included nerve-root compression (κ = 0.14) and vertebral body height loss (κ = 0.19).

CONCLUSIONS

The range of agreement between musculoskeletal radiologists and orthopedic surgeons for most spinal assessment criteria is moderate to poor. A consensus for managing challenging vertebral injuries secondary to spinal metastases needs to be established so as to best triage patients to the most appropriate therapeutic modality.

Involvement of decreased hypoxia-inducible factor 1 activity and resultant G1-S cell cycle transition in radioresistance of perinecrotic tumor cells

Cancer patients often suffer from local tumor recurrence after radiation therapy. Some intracellular and extracellular factors, such as activity of hypoxia-inducible factor 1 (HIF-1), cell cycle status and oxygen availability, have been suggested to affect DNA damage responses and eventual radioresistant characteristics of cancer cells. But when, where, and how these factors affect one another and induce cellular radioresistance is largely unknown. Here, we analyzed mechanistic and spatio-temporal relationships among them in highly heterogeneous tumor microenvironments. Experiments in vitro demonstrated that a decrease in the glucose concentration reduced the transcriptional activity of HIF-1 and expression of a downstream gene for the cell cycle regulator p27^Kip1 even under hypoxic conditions. Then, the proportion of cells in the radioresistant S phase increased, whereas that in the radiosensitive G₁ phase decreased, significantly. Immunohistochemical analyses showed that cancer cells in perinecrotic hypoxic regions, which should be under low-glucose conditions, expressed little HIF-1α, and therefore, were mainly in S phase and less damaged by radiation treatment. Continuous administration of glucagon, which increases the blood glucose concentration and so improves glucose availability in perinecrotic hypoxic regions, induced HIF-1α expression and increased radiation-induced DNA damage. Taken all together, these results indicate that cancer cells in perinecrotic regions, which would be under low-glucose and hypoxic conditions, obtain radioresistance by decreasing the level of both HIF-1 activity and p27^Kip1 expression, and adjusting their cell cycle to the radioresistant S phase.

Role of zonal flow predator-prey oscillations in triggering the transition to H-mode confinement

Direct evidence of zonal flow (ZF) predator-prey oscillations and the synergistic roles of ZF- and equilibrium E×B flow shear in triggering the low- to high-confinement (L- to H-mode) transition in the DIII-D tokamak is presented. Periodic turbulence suppression is first observed in a narrow layer at and just inside the separatrix when the shearing rate transiently exceeds the turbulence decorrelation rate. The final transition to H mode with sustained turbulence and transport reduction is controlled by equilibrium E×B shear due to the increasing ion pressure gradient.

Association of β-cell function and insulin sensitivity with fasting and 2-h plasma glucose in a large Chinese population

AIM

Our aim was to provide a quantitative analysis of the changes in the principal determinants of insulin sensitivity and secretion in relation to fasting plasma glucose (FPG) or 2-h plasma glucose (2h PG) in a Chinese population with a wide range of glucose tolerance.

METHODS

A total of 5728 adults spanning the entire range of glucose tolerance were included. Insulin sensitivity was measured by Matsuda insulin sensitivity index (ISI(M)) and homeostasis model assessment of 1/homeostasis model assessment of insulin resistance (HOMA-IR). β-Cell function adjusted by insulin sensitivity was assessed from disposition index (DI) at early-phase DI(30) and total DI(120). The exponential curve was established as the best fit for the relationship between insulin sensitivity or β-cell function and FPG or 2h PG.

RESULTS

Relative to the trend classified as increasing 2h PG, hepatic insulin sensitivity and insulin secretion showed a decreasing trend to a substantial degree as FPG increased. A 1 mmol/l increase in FPG and 2h PG concentration was associated with a -22 and -21% decline in ISI(M), -16 and -4% in 1/HOMA-IR, -38 and -35% in DI(30) and -36 and -26% in DI(120). The decay constant of ISI(M) and DI(30) in IFG or ISI(M), 1/HOMA-IR, DI(30) and DI(120) in IGT was lower than that in normal glucose tolerance. Significant interactions between sex and glucose levels determining DI were found.

CONCLUSIONS

We conclude that impairment of insulin sensitivity and insulin secretion contributes to both FPG or 2h PG hyperglycaemia in a Chinese population, but that the decline in insulin secretion is more pronounced with increasing fasting than 2h PG.

A Bayesian approach to risk-adjusted outcome monitoring in healthcare

Clinical outcomes are commonly monitored in healthcare practices to detect changes in care providers' performance. One key challenge in outcome monitoring is the need of adjustment for patient base-line risks. Various control charting methods have been developed to conduct risk-adjusted outcome monitoring, but they all rely on the availability of a large number of historical data. We propose a Bayesian approach to this type of monitoring for cases where historical data are not available. In our approach, detection of change is formulated as a model-selection problem and solved using a popular Bayesian tool for variable selection, the Bayes factor. Issues in decision-making about whether there is a change point in the observed patient outcomes are addressed, including specification of priors and computation of Bayes factors. This approach is applied to a real data set on cardiac surgeries, and its performance under different parameter scenarios is studied through simulations.

Update on the systematic review of palliative radiotherapy trials for bone metastases

AIMS

To update previous meta-analyses of randomised palliative radiotherapy trials comparing single fractions versus multiple fractions.

MATERIALS AND METHODS

All published randomised controlled trials comparing single fraction versus multiple fraction schedules for the palliation of uncomplicated bone metastases were included in this analysis. Odds ratios and 95% confidence intervals were calculated for each trial. Forest plots were created using a random effects model and the Mantel-Haenszel statistic.

RESULTS

In total, 25 randomised controlled trials were identified. For intention-to-treat patients, the overall response rate was similar in patients receiving single fractions (1696 of 2818; 60%) and multiple fractions (1711 of 2799; 61%). Complete response rates were 620 of 2641 (23%) in the single fraction arm and 634 of 2622 (24%) in the multiple fraction arm. No significant difference was seen in overall or complete response rates. Pathological fracture did not favour either arm, but spinal cord compression trended towards favouring multiple fractions; however, neither was statistically significant (P = 0.72 and P = 0.13, respectively). Retreatment rates favoured patients in the multiple fraction arm, where the likelihood of requiring re-irradiation was 2.6-fold greater in the single fraction arm (95% confidence interval: 1.92-3.47; P < 0.00001). Repeated analyses excluding drop-out patients did not alter these findings. In general, no significant differences in acute toxicities were seen.

CONCLUSION

Overall and complete response rates were similar in both intention-to-treat and assessable patients. Single and multiple fraction regimens provided equal pain relief; however, significantly higher retreatment rates occurred in those receiving single fractions.