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A disruption database characterizing the current quench of disruptions with ITER-like tungsten divertor has been developed on EAST. It provides a large number of plasma parameters describing the predisruptive plasma, current quench time, eddy current, and mitigation by massive impurity injection, which shows that the current quench time strongly depends on magnetic energy and post-disruption electron temperature. Further, the energy balance and magnetic energy dissipation during the current quench phase has been well analysed. Magnetic energy is also demonstrated to be dissipated mainly by ohmic reheating and inductive coupling, and both of the two channels have great effects on current quench time. Also, massive gas injection is an efficient method to speed up the current quench and increase the fraction of impurity radiation.
Diet has a major influence on the composition and metabolic output of the gut microbiome. Higher-protein diets are often recommended for older consumers; however, the effect of high-protein diets on the gut microbiota and faecal volatile organic compounds (VOC) of elderly participants is unknown. The purpose of the study was to establish if the faecal microbiota composition and VOC in older men are different after a diet containing the recommended dietary intake (RDA) of protein compared with a diet containing twice the RDA (2RDA). Healthy males (74⋅2 (sd 3⋅6) years; n 28) were randomised to consume the RDA of protein (0⋅8 g protein/kg body weight per d) or 2RDA, for 10 weeks. Dietary protein was provided via whole foods rather than supplementation or fortification. The diets were matched for dietary fibre from fruit and vegetables. Faecal samples were collected pre- and post-intervention for microbiota profiling by 16S ribosomal RNA amplicon sequencing and VOC analysis by head space/solid-phase microextraction/GC-MS. After correcting for multiple comparisons, no significant differences in the abundance of faecal microbiota or VOC associated with protein fermentation were evident between the RDA and 2RDA diets. Therefore, in the present study, a twofold difference in dietary protein intake did not alter gut microbiota or VOC indicative of altered protein fermentation.
Feathers play a critical role in thermoregulation and directly influence poultry production. Poor feathering adversely affects living appearance and carcass quality, thus reducing profits. However, producers tend to ignore the importance of feather development and do not know the laws of feather growth and development. The objective of this study was to fit growth curves to describe the growth and development of feathers in yellow-feathered broilers during the embryonic and posthatching periods using different nonlinear functions (Gompertz, logistic and Bertalanffy). Feather mass and length were determined during the embryonic development and posthatching stages to identify which growth model most accurately described the feather growth pattern. The results showed that chick embryos began to grow feathers at approximately embryonic (E) day 10, and the feathers grew rapidly from E13 to E17. There was little change from E17 to the day of hatching (DOH). During the embryonic period, the Gompertz function (Y = 798.48e−203 431exp(−0.87t), Akaike’s information criterion (AIC) = −0.950 × 103, Bayesian information criterion (BIC) = −0.711 × 103 and mean square error (MSE) = 559.308) provided the best fit for the feather growth curve compared with the other two functions. After hatching, feather mass and length changed little from the DOH to day (D) 14, increased rapidly from D21 to D91 and then grew slowly after D91. The first stage of feather molting occurred from 2 to 3 weeks of age when the down feathers were mostly shed and replaced with juvenile feathers, and the second stage occurred at approximately 13 to 15 weeks of age. The three nonlinear functions could overall fit the feather growth curve well, but the Bertalanffy model (Y = 116.88 × (1−0.86e−0.02t)3, AIC = 1.065 × 105, BIC = 1.077 × 105 and MSE = 11.308) showed the highest degree of fit among the models. Therefore, the Gompertz model exhibited the best goodness of fit for the feather growth curve during the embryonic development, while the Bertalanffy model was the most suitable model due to its accurate ability to predict the growth and development of feathers during the growth period, which is an important commercial characteristic of yellow-feathered chickens.
Disruptions with runaway electron generation have been deliberately induced by injection of argon using a disruption mitigation valve. A second disruption mitigation valve has been utilised to inject varying amounts of helium after a short time delay. No generation of runaway electrons has been observed when more than a critical amount of helium has been injected no later than 5 ms after the triggering of the first valve. The required amount of helium for suppression of runaway electron generation is up to one order of magnitude lower than the critical density according to Connor & Hastie (1975) and Rosenbluth & Putvinski (1997).
Based on the analysis of data from the numerous dedicated experiments on plasma disruptions in the TEXTOR tokamak the mechanisms of the formation of runaway electron (RE) beams and their losses are proposed. The plasma disruption is caused by a strong stochastic magnetic field formed due to nonlinearly excited low-mode-number magneto-hydro-dynamics (MHD) modes. It is hypothesized that the RE beam is formed in the central plasma region confined by an intact magnetic surface due to the acceleration of electrons by the inductive toroidal electric field. In the case of plasmas with the safety factor
the most stable RE beams are formed by the outermost intact magnetic surface located between the magnetic surface
and the closest low-order rational surface
. The thermal quench (TQ) time caused by the fast electron transport in a stochastic magnetic field is calculated using the collisional transport model. The current quench (CQ) stage is due to the particle transport in a stochastic magnetic field. The RE beam current is modelled as a sum of a toroidally symmetric part and a small-amplitude helical current with a predominant
component. The REs are lost due to two effects: (i) by outward drift of electrons in a toroidal electric field until they touch the wall and (ii) by the formation of a stochastic layer of REs at the beam edge. Such a stochastic layer for high-energy REs is formed in the presence of the
MHD mode. It has a mixed topological structure with a stochastic region open to the wall. The effect of external resonant magnetic perturbations on RE loss is discussed. A possible cause of the sudden MHD signals accompanied by RE bursts is explained by the redistribution of runaway current during the resonant interaction of high-energetic electron orbits with the
Experimental evidence supporting the theory of hot tail runaway electron (RE) generation has been identified in TEXTOR disruptions. With higher temperature, more REs are generated during the thermal quench. Increasing the RE generation by increasing the temperature, an obvious RE plateau is observed even with low toroidal magnetic field (1.7 T). These results explain the previously found electron density threshold for RE generation.
Thermoelectric (TE) generators have very important applications, such as emerging automotive waste heat recovery and cooling applications. However, reliable transport properties characterization techniques are needed in order to scale-up module production and thermoelectric generator design. DOE round-robin testing found that literature values for figure of merit (ZT) are sometimes not reproducible in part for the lack of standardization of transport properties measurements. In Sandia National Laboratories (SNL), we have been optimizing transport properties measurements techniques of TE materials and modules. We have been using commercial and custom-built instruments to analyze the performance of TE materials and modules. We developed a reliable procedure to measure thermal conductivity, seebeck coefficient and resistivity of TE materials to calculate the ZT as function of temperature. We use NIST standards to validate our procedures and measure multiple samples of each specific material to establish consistency. Using these developed thermoelectric capabilities, we studied transport properties of Bi2Te3 based alloys thermal aged up to 2 years. Parallel with analytical and microscopy studies, we correlated transport properties changes with chemical changes. Also, we have developed a resistance mapping setup to measure the contact resistance of Au contacts on TE materials and TE modules as a whole in a non-destructive way. The development of novel but reliable characterization techniques has been fundamental to better understand TE materials as function of aging time, temperature and environmental conditions.
We report experiments and molecular dynamics calculations on the kinetics of electrodeposited lithium dendrites relaxation as a function of temperature and time. We found that the experimental average length of dendrite population decays via stretched exponential functions of time toward limiting values that depend inversely on temperature. The experimental activation energy derived from initial rates as Ea∼ 6-7 kcal/mole, which is closely matched by MD calculations, based on the ReaxFF force field for metallic lithium. Simulations reveal that relaxation proceeds in several steps via increasingly larger activation barriers. Incomplete relaxation at lower temperatures is therefore interpreted a manifestation of cooperative atomic motions into discrete topologies that frustrate monotonic progress by ‘caging’.
A cluster dynamics model based on rate theory has been developed to describe the accumulation and diffusion processes of helium in tungsten under helium implantation alone or synergistic irradiation with neutron, by involving different types of objects, adopting up-to-date parameters and complex reaction processes as well as considering the diffusion process along with depth. The calculated results under different conditions are in good agreement with experiments much well. The model describes the behavior of helium in tungsten within 2D space of defect type/size and depth on different ions incident conditions (energies and fluences) and material conditions (system temperature and existent sinks), by including the synergistic effect of helium-neutron irradiations and the influence of inherent sinks (dislocation lines and grain boundaries). The model, coded as IRadMat, would be universally applicable to the evolution of defects for ions/neutron irradiated on plasma-facing materials.
The pathogenesis of angiostrongyliasis, resulting from Angiostrongylus cantonensis invasion of the human central nervous system, remains elusive. Anthelmintics are usually used to kill worms, although dead worms in the brain may cause severe inflammation which will lead to central nervous system damage. Therefore, combination therapy with anthelmintics and anti-inflammatory drugs in the treatment of human angiostrongyliasis needs further study. To evaluate the efficacy of albendazole combined with a marine fungal extract (m2-9) in A. cantonensis infection, BALB/c mice infected by the third-stage larvae of A. cantonensis were divided into three groups: mice treated with albendazole or m2-9 alone or in combination from day 5 post-inoculation (PI). Several efficacy parameters were recorded, including weight change, worm recovery, neurological function, behavioural analysis, eosinophil and leucocyte counts. The results showed that combination therapy increased body weight, reduced worm burden, improved learning ability, memory and action, decreased neurological dysfunction and leucocyte response in these mice. The combination of albendazole and m2-9 treatment significantly decreased leucocyte response and increased the frequency of rearing, compared to infected mice treated with either drug alone. Therefore, m2-9 is a natural product with potentially significant therapeutic value for angiostrongyliasis and is worthy of further study.
We retrospectively analysed the epidemiological data of all hand, foot, and mouth disease (HFMD) cases from the largest paediatric infectious diseases centre in Shanghai between 2007 and 2010. A total of 28 058 outpatients were diagnosed with HFMD, of which 3948 (14·07%) were hospitalized, 730 (2·60%) had complications with neurological disorders and pulmonary oedema/haemorrhage, and 11 (0·04%) died. The peak season was the summer months. Boys were more affected than girls. Since 2008, the major population group affected has shifted from native Shanghainese children attending preschool to migrant children and younger children cared for at home. Children aged 1–4 years constituted 82·27% of cases. EV-A71 was tested in clinical samples taken from severe cases in 2009 and 2010, and from most inpatients in 2010. EV-A71 was positive in 99·17% and 86·31% of severe cases, respectively in 2009 and 2010. All 12 cases with pulmonary oedema or haemorrhage were infected with EV-A71. Ten (90·90%) of 11 fatal cases were attributable to EV-A71 infection. In 2010, EV-A71-positive cases accounted for 54·12% of inpatients. The dominant circulation of EV-A71 led to the outbreak of HFMD and occurrence of severe and fatal cases.
Electronic medical records (EMR) provide a unique opportunity for efficient, large-scale clinical investigation in psychiatry. However, such studies will require development of tools to define treatment outcome.
Natural language processing (NLP) was applied to classify notes from 127 504 patients with a billing diagnosis of major depressive disorder, drawn from out-patient psychiatry practices affiliated with multiple, large New England hospitals. Classifications were compared with results using billing data (ICD-9 codes) alone and to a clinical gold standard based on chart review by a panel of senior clinicians. These cross-sectional classifications were then used to define longitudinal treatment outcomes, which were compared with a clinician-rated gold standard.
Models incorporating NLP were superior to those relying on billing data alone for classifying current mood state (area under receiver operating characteristic curve of 0.85–0.88 v. 0.54–0.55). When these cross-sectional visits were integrated to define longitudinal outcomes and incorporate treatment data, 15% of the cohort remitted with a single antidepressant treatment, while 13% were identified as failing to remit despite at least two antidepressant trials. Non-remitting patients were more likely to be non-Caucasian (p<0.001).
The application of bioinformatics tools such as NLP should enable accurate and efficient determination of longitudinal outcomes, enabling existing EMR data to be applied to clinical research, including biomarker investigations. Continued development will be required to better address moderators of outcome such as adherence and co-morbidity.
Echocardiography detects a greater prevalence of rheumatic heart disease than heart auscultation. Echocardiographic screening for rheumatic heart disease combined with secondary prophylaxis may potentially prevent severe rheumatic heart disease in high-risk populations. We aimed to determine the prevalence of rheumatic heart disease in children from an urban New Zealand population at high risk for acute rheumatic fever.
Methods and results
To optimise accurate diagnosis of rheumatic heart disease, we utilised a two-step model. Portable echocardiography was conducted on 1142 predominantly Māori and Pacific children aged 10–13 years. Children with an abnormal screening echocardiogram underwent clinical assessment by a paediatric cardiologist together with hospital-based echocardiography. Rheumatic heart disease was then classified as definite, probable, or possible. Portable echocardiography identified changes suggestive of rheumatic heart disease in 95 (8.3%) of 1142 children, which reduced to 59 (5.2%) after cardiology assessment. The prevalence of definite and probable rheumatic heart disease was 26.0 of 1000, with 95% confidence intervals ranging from 12.6 to 39.4. Portable echocardiography overdiagnosed rheumatic heart disease with physiological valve regurgitation diagnosed in 28 children. A total of 30 children (2.6%) had non-rheumatic cardiac abnormalities, 11 of whom had minor congenital mitral valve anomalies.
We found high rates of undetected rheumatic heart disease in this high-risk population. Rheumatic heart disease screening has resource implications with cardiology evaluation required for accurate diagnosis. Echocardiographic screening for rheumatic heart disease may overdiagnose rheumatic heart disease unless congenital mitral valve anomalies and physiological regurgitation are excluded.
A brief overview of the research activities at the Thermionic Energy Conversion (TEC) Center is given. The goal is to achieve direct thermal to electric energy conversion with >20% efficiency and >1W/cm2 power density at a hot side temperature of 300–650C. Thermionic emission in both vacuum and solid-state devices is investigated. In the case of solid-state devices, hot electron filtering using heterostructure barriers is used to increase the thermoelectric power factor. In order to study electron transport above the barriers and lateral momentum conservation in thermionic emission process, the current-voltage characteristic of ballistic transistor structures is investigated. Embedded ErAs nanoparticles and metal/semiconductor multilayers are used to reduce the lattice thermal conductivity. Cross-plane thermoelectric properties and the effective ZT of the thin film are analyzed using the transient Harman technique. Integrated circuit fabrication techniques are used to transfer the n- and p-type thin films on AlN substrates and make power generation modules with hundreds of thin film elements. For vacuum devices, nitrogen-doped diamond and carbon nanotubes are studied for emitters. Sb-doped highly oriented diamond and low electron affinity AlGaN are investigated for collectors. Work functions below 1.6eV and vacuum thermionic power generation at temperatures below 700C have been demonstrated.
The investigation of nanocrystalline Ge (nc-Ge) directly prepared with high dose Ge ion implantation of 1×1016, 1×1017, 5×1017 and 1×1018cm-2 respectively without subsequent annealing is presented in this paper. The specimens were measured by means of GIXRD, LRS and PL. The results show the nc-Ge, which possesses strong compressive stress, can be fabricated when the implanting dose of Ge ions is over the threshold dose∼1×1017cm-2. The content and size of nc-Ge will enlarge with increasing dose. The nc-Ge formation mechanism may be the Ge atoms in the amorphous Ge (a-Ge) clusters, which are formed through the aggregation of implanted Ge ions, obtain energy from the instant local annealing zone induced by the incident Ge ion and reconstruct to nc-Ge existing in a-Ge clusters. The PL results indicate the strong PL peaks centered at about 295, 400 and 570 nm can be observed in implanted samples. The intensity of these PL peaks increases with increasing dose. The related PL mechanism in Ge-ion-implanted SiO2 film has also been discussed.
A diffuse phase transition for Pb(Zn1/3Nb2/3)O3–PbZrO3–PbTiO3 (PZN-PZ-PT) system in the rhombohedral region near the rhombohedral/tetragonal morphotropic phase boundary (MPB) is reported in this paper. A thermal-driven macrodomain– microdomain switching was revealed and confirmed for compositions close to the MPB in the rhombohedral region after poling. Morever, the transition from rhombohedral phase to tetragonal phase was first revealed in the curves of dielectric permittivity (or dissipation factor) versus temperature. This rhombohedral–tetragonal phase transition resulted from the MPB bending toward the rhombohedral phase region and was confirmed by high-temperature x-ray diffraction.