A high-density and high-confinement tokamak plasma regime for fusion energy.

The tokamak approach, utilizing a toroidal magnetic field configuration to confine a hot plasma, is one of the most promising designs for developing reactors that can exploit nuclear fusion to generate electrical energy1,2. To reach the goal of an economical reactor, most tokamak reactor designs3-10 simultaneously require reaching a plasma line-averaged density above an empirical limit-the so-called Greenwald density11-and attaining an energy confinement quality better than the standard high-confinement mode12,13. However, such an operating regime has never been verified in experiments. In addition, a long-standing challenge in the high-confinement mode has been the compatibility between a high-performance core and avoiding large, transient edge perturbations that can cause very high heat loads on the plasma-facing-components in tokamaks. Here we report the demonstration of stable tokamak plasmas with a line-averaged density approximately 20% above the Greenwald density and an energy confinement quality of approximately 50% better than the standard high-confinement mode, which was realized by taking advantage of the enhanced suppression of turbulent transport granted by high density-gradients in the high-poloidal-beta scenario14,15. Furthermore, our experimental results show an integration of very low edge transient perturbations with the high normalized density and confinement core. The operating regime we report supports some critical requirements in many fusion reactor designs all over the world and opens a potential avenue to an operating point for producing economically attractive fusion energy.

Robust Avoidance of Edge-Localized Modes alongside Gradient Formation in the Negative Triangularity Tokamak Edge.

In a series of high performance diverted discharges on DIII-D, we demonstrate that strong negative triangularity (NT) shaping robustly suppresses all edge-localized mode (ELM) activity over a wide range of plasma conditions: ⟨n⟩=0.1-1.5×10^{20} m^{-3}, P_{aux}=0-15 MW, and |B_{t}|=1-2.2 T, corresponding to P_{loss}/P_{LH08}∼8. The full dataset is consistent with the theoretical prediction that magnetic shear in the NT edge inhibits access to ELMing H-mode regimes; all experimental pressure profiles are found to be at or below the infinite-n ballooning stability limit. Our present dataset also features edge pressure gradients in strong NT that are closer to an H-mode than a typical L-mode plasma, supporting the consideration of NT for reactor design.

Integration of full divertor detachment with improved core confinement for tokamak fusion plasmas.

Divertor detachment offers a promising solution to the challenge of plasma-wall interactions for steady-state operation of fusion reactors. Here, we demonstrate the excellent compatibility of actively controlled full divertor detachment with a high-performance (ßN ~ 3, H98 ~ 1.5) core plasma, using high-ßp (poloidal beta, ßp > 2) scenario characterized by a sustained core internal transport barrier (ITB) and a modest edge transport barrier (ETB) in DIII-D tokamak. The high-ßp high-confinement scenario facilitates divertor detachment which, in turn, promotes the development of an even stronger ITB at large radius with a weaker ETB. This self-organized synergy between ITB and ETB, leads to a net gain in energy confinement, in contrast to the net confinement loss caused by divertor detachment in standard H-modes. These results show the potential of integrating excellent core plasma performance with an efficient divertor solution, an essential step towards steady-state operation of reactor-grade plasmas.

Achievement of Reactor-Relevant Performance in Negative Triangularity Shape in the DIII-D Tokamak.

Plasma discharges with a negative triangularity (δ=-0.4) shape have been created in the DIII-D tokamak with a significant normalized beta (ß_{N}=2.7) and confinement characteristic of the high confinement mode (H_{98y2}=1.2) despite the absence of an edge pressure pedestal and no edge localized modes (ELMs). These inner-wall-limited plasmas have a similar global performance as a positive triangularity (δ=+0.4) ELMing H-mode discharge with the same plasma current, elongation and cross sectional area. For cases both of dominant electron cyclotron heating with T_{e}/T_{i}>1 and dominant neutral beam injection heating with T_{e}/T_{i}=1, turbulent fluctuations over radii 0.5<ρ<0.9 were reduced by 10-50% in the negative triangularity shape compared to the matching positive triangularity shape, depending on the radius and conditions.

After the war is over: the role of General Sir Arthur Currie in the development of academic medicine in Canada

Summary: Canadian universities faced a challenge with the return of a large cohort of battle-hardened students and faculty from the First World War. General Sir Arthur Currie, considered one of the few successful generals of the war, returned to a welcome of silence in Canada. McGill University exploited the opportunity to recruit him as its president. Currie oversaw a campaign of building construction and faculty development at McGill that also had a significant effect on the rest of Canada. Through his fostering of the Montreal Neurological Institute and the recruitment of Dr. Wilder Penfield, Currie facilitated the development of multidisciplinary medicine, which integrates clinical care with research ­ an aspiration still held by specialty medicine in Canada today.

Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D.

Thomson scattering produces ne profiles from measurement of scattered laser beam intensity. Rayleigh scattering provides a first calibration of the relation ne ∝ ITS, which depends on many factors (e.g., laser alignment and power, optics, and measurement systems). On DIII-D, the ne calibration is adjusted against an absolute ne from the density-driven cutoff of the 48 channel 2nd harmonic X-mode electron cyclotron emission system. This method has been used to calibrate Thomson ne from the edge to near the core (r/a > 0.15). Application of core electron cyclotron heating improves the quality of cutoff and depth of its penetration into the core, and also changes underlying MHD activity, minimizing crashes which confound calibration. Less fueling is needed as "ECH pump-out" generates a plasma ready to take up gas. On removal of gyrotron power, cutoff penetrates into the core as channels fall successively and smoothly into cutoff.

Avoiding Tokamak Disruptions by Applying Static Magnetic Fields That Align Locked Modes with Stabilizing Wave-Driven Currents.

Nonrotating ("locked") magnetic islands often lead to complete losses of confinement in tokamak plasmas, called major disruptions. Here locked islands were suppressed for the first time, by a combination of applied three-dimensional magnetic fields and injected millimeter waves. The applied fields were used to control the phase of locking and so align the island O point with the region where the injected waves generated noninductive currents. This resulted in stabilization of the locked island, disruption avoidance, recovery of high confinement, and high pressure, in accordance with the expected dependencies upon wave power and relative phase between the O point and driven current.

Incidence and determinants of 1-month mortality after cancer-directed surgery.

BACKGROUND: Death within 1 month of surgery is considered treatment related and serves as an important health care quality metric. We sought to identify the incidence of and factors associated with 1-month mortality after cancer-directed surgery. PATIENTS AND METHODS: We used the Surveillance, Epidemiology and End Results Program to study a cohort of 1 110 236 patients diagnosed from 2004 to 2011 with cancers that are among the 10 most common or most fatal who received cancer-directed surgery. Multivariable logistic regression analyses were used to identify factors associated with 1-month mortality after cancer-directed surgery. RESULTS: A total of 53 498 patients (4.8%) died within 1 month of cancer-directed surgery. Patients who were married, insured, or who had a top 50th percentile income or educational status had lower odds of 1-month mortality from cancer-directed surgery {[adjusted odds ratio (AOR) 0.80; 95% confidence interval (CI) 0.79-0.82; P < 0.001], (AOR 0.88; 95% CI 0.82-0.94; P < 0.001), (AOR 0.95; 95% CI 0.93-0.97; P < 0.001), and (AOR 0.98; 95% CI 0.96-0.99; P = 0.043), respectively}. Patients who were non-white minority, male, or older (per year increase), or who had advanced tumor stage 4 disease all had a higher risk of 1-month mortality after cancer-directed surgery, with AORs of 1.13 (95% CI 1.11-1.15), P < 0.001; 1.11 (95% CI 1.08-1.13), P < 0.001; 1.02 (95% 1.02-1.03), P < 0.001; and 1.89 (95% CI 1.82-1.95), P < 0.001 respectively. CONCLUSIONS: Unmarried, uninsured, non-white, male, older, less educated, and poorer patients were all at a significantly higher risk for death within 1 month of cancer-directed surgery. Efforts to reduce 1-month surgical mortality and eliminate sociodemographic disparities in this adverse outcome could significantly improve survival among patients with cancer.

Tokamak operation with safety factor q95 < 2 via control of MHD stability.

Magnetic feedback control of the resistive-wall mode has enabled the DIII-D tokamak to access stable operation at safety factor q(95) = 1.9 in divertor plasmas for 150 instability growth times. Magnetohydrodynamic stability sets a hard, disruptive limit on the minimum edge safety factor achievable in a tokamak, or on the maximum plasma current at a given toroidal magnetic field. In tokamaks with a divertor, the limit occurs at q(95) = 2, as confirmed in DIII-D. Since the energy confinement time scales linearly with current, this also bounds the performance of a fusion reactor. DIII-D has overcome this limit, opening a whole new high-current regime not accessible before. This result brings significant possible benefits in terms of fusion performance, but it also extends resistive-wall mode physics and its control to conditions never explored before. In present experiments, the q(95) < 2 operation is eventually halted by voltage limits reached in the feedback power supplies, not by intrinsic physics issues. Improvements to power supplies and to control algorithms have the potential to further extend this regime.

The association between insurance status and prostate cancer outcomes: implications for the Affordable Care Act.

BACKGROUND: The Affordable Care Act (ACA) aims to expand health insurance coverage to over 30 million previously uninsured Americans. To help evaluate the potential impact of the ACA on prostate cancer care, we examined the associations between insurance coverage and prostate cancer outcomes among men <65 years old who are not yet eligible for Medicare. METHODS: The Surveillance, Epidemiology and End Results Program was used to identify 85 203 men aged <65 years diagnosed with prostate cancer from 2007 to 2010. Multivariable logistic regression modeled the association between insurance status and stage at presentation. Among men with high-risk disease, the associations between insurance status and receipt of definitive therapy, prostate cancer-specific mortality (PCSM) and all-cause mortality were determined using multivariable logistic, Fine and Gray competing-risks and Cox regression models, respectively. RESULTS: Uninsured patients were more likely to be non-white and come from regions of rural residence, lower median household income and lower education level (P<0.001 for all cases). Insured men were less likely to present with metastatic disease (adjusted odds ratio (AOR) 0.23; 95% confidence interval (CI) 0.20-0.27; P<0.001). Among men with high-risk disease, insured men were more likely to receive definitive treatment (AOR 2.29; 95% CI 1.81-2.89; P<0.001), and had decreased PCSM (adjusted hazard ratio 0.56; 95% CI 0.31-0.98; P=0.04) and all-cause mortality (adjusted hazard ratio 0.60; 0.39-0.91; P=0.01). CONCLUSIONS: Insured men with prostate cancer are less likely to present with metastatic disease, more likely to be treated if they develop high-risk disease and are more likely to survive their cancer, suggesting that expanding health coverage under the ACA may significantly improve outcomes for men with prostate cancer who are not yet eligible for Medicare.

Isolation and characterisation of a novel Bohle-like virus from two frog species in the Darwin rural area, Australia.

Twelve captive magnificent tree frogs Litoria splendida and 2 green tree frogs L. caerulea on a property in the Darwin rural area (Northern Territory, Australia) either died or were euthanased after becoming lethargic or developing skin lesions. Samples from both species of frog were submitted for histopathology and virus isolation. An irido-like virus was cultured from tissue samples taken from both species and was characterised using electron microscopy, restriction enzyme digests and nucleic acid amplification and sequencing. The isolates were determined to belong to the genus Ranavirus, were indistinguishable from each other and shared a 98.62% nucleotide similarity and a 97.32% deduced amino acid homology with the Bohle iridovirus over a 1161 bp region of the major capsid gene. This is the first isolation of a ranavirus from amphibians in the Northern Territory and the first report of natural infection in these 2 species of native frog. The virus is tentatively named Mahaffey Road virus (MHRV).

Fatal cetacean morbillivirus infection in an Australian offshore bottlenose dolphin (Tursiops truncatus).

A juvenile offshore bottlenose dolphin (Tursiops truncatus) was found stranded with neurological signs and unable to swim or float unassisted. It subsequently died, succumbing to a combination of severe pneumonia and encephalitis. Morbillivirus serum neutralisation test serology was positive (titre 1:16) for cetacean morbillivirus and negative for both phocine distemper virus and canine distemper virus. There was concurrent thymic and lymph node lymphoid depletion and necrosis, together with intranuclear and intracytoplasmic acidophilic viral inclusion bodies and multinucleate syncytia within multiple organs. Paramyxovirus capsids were identified in lung sections via electron microscopy and morbillivirus antigen was demonstrated within sections of lung, thymus and brain by immunohistochemistry. Reverse transcription-polymerase chain reaction for morbillivirus nucleoprotein (N) and phosphoprotein (P) genes were positive and phylogenetic gene product sequence analysis revealed 98% and 94% sequence identity to dolphin morbillivirus, respectively. To the authors' knowledge, this is the first report of a cetacean mortality due to morbillivirus infection occurring in the southern hemisphere. Morbillivirus infection should be included in the differential diagnosis of stranded live or dead cetaceans in Australian waters, particularly if animals display neurological signs.

Isolation and characterization of koi herpesvirus (KHV) from Indonesia: identification of a new genetic lineage.

Koi herpesvirus (KHV) is the aetiological agent of an emerging disease (KHVD) associated with mass mortalities in koi and common carp and reported from at least 30 countries. We report the first isolation of KHV from koi and common carp in Indonesia and initial characterization of the isolates. Clinical signs, histopathology and virion morphology are similar to those of isolates from other countries. Phylogenetic analyses using the thymidine kinase gene amplified from each isolate and from carp tissue samples collected from KHVD outbreaks throughout Indonesia indicated that the Indonesian isolates are more closely related to the Asian than the European KHV lineage. Sequence analysis of two other variable regions between ORF29 and ORF31 (marker I) and near the start of ORF 133 (marker II) indicated that all Indonesian isolates displayed a marker I allele (I(++)) previously identified only in isolates of the Asian lineage. However, in the marker II region, all Indonesian isolates displayed the II(-) allele, which has been reported previously only amongst isolates of the European lineage, and nine of these displayed a mixed genotype (II(+)II(-)). The I(++)II(-) genotype has not been reported previously and appears to represent a new intermediate lineage that may have emerged in Indonesia.

Family Iridoviridae: poor viral relations no longer.

Members of the family Iridoviridae infect a diverse array of invertebrate and cold-blooded vertebrate hosts and are currently viewed as emerging pathogens of fish and amphibians. Iridovirid replication is unique and involves both nuclear and cytoplasmic compartments, a circularly permuted, terminally redundant genome that, in the case of vertebrate iridoviruses, is also highly methylated, and the efficient shutoff of host macromolecular synthesis. Although initially neglected largely due to the perceived lack of health, environmental, and economic concerns, members of the genus Ranavirus, and the newly recognized genus Megalocytivirus, are rapidly attracting growing interest due to their involvement in amphibian population declines and their adverse impacts on aquaculture. Herein we describe the molecular and genetic basis of viral replication, pathogenesis, and immunity, and discuss viral ecology with reference to members from each of the invertebrate and vertebrate genera.

Determining causality and controlling disease is based on collaborative research involving multidisciplinary approaches.

Understanding the causes of infectious disease to facilitate better control requires observational and experimental studies. Often these must be conducted at many scales such as at the molecular, cellular, organism, and population level. Studies need to consider both intrinsic and extrinsic factors affecting the pathogen/host interaction. They also require a combination of study methods covered by disciplines such as pathology, epidemiology, microbiology, and ecology. Therefore, it is important that disciplines work together when designing and conducting studies. Finally, we need to integrate and interpret data across levels and disciplines to better formulate control strategies. This requires another group of specialists with broad cross-disciplinary training in epidemiology and an ability to readily work with others.

Dust measurements in tokamaks (invited).

Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 microm in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C(2) dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.

Viral morphogenesis and morphological changes in human neuronal cells following Tioman and Menangle virus infection.

Tioman virus (TioPV) and Menangle virus (MenPV) are two antigenically and genetically related paramyxoviruses (genus: Rubulavirus, family: Paramyxoviridae) isolated from Peninsular Malaysia (2001) and Australia (1997), respectively. Both viruses are potential zoonotic agents. In the present study, the infectivity, growth kinetics, morphology and morphogenesis of these two paramyxoviruses in a human neuronal cell (SK-N-SH) line were investigated. Sub-confluent SK-N-SH cells were infected with TioPV and MenPV at similar multiplicity of infection. These cells were examined by conventional and immunoelectron microscopy, and virus titres in the supernatants were assayed. Syncytia were observed for both infections in SK-N-SH cells and were more pronounced during the early stages of TioPV infection. The TioPV titre increased consistently (10(1)) every 12 h after infection. In MenPV-infected cells, cellular material was frequently observed within budding virions, and microfilaments and microtubules were abundant. Viral budding was common, and extracellular MenPVs tended to be more pleomorphic compared to TioPVs, which appeared to be more spherical in appearance. The MenPV cytoplasmic viral inclusion appeared to be comparatively smaller, loose and interspersed with randomly scattered circle-like particles, whereas huge tubule-like cytoplasmic inclusions were observed in TioPV-infected cells. Both viruses also displayed different cellular pathology in the SK-N-SH cells. The intracellular ultrastructural characteristics of these two viruses in infected neuronal cells may allow them to be differentiated by electron microscopy.