A sustained high-temperature fusion plasma regime facilitated by fast ions.

Nuclear fusion is one of the most attractive alternatives to carbon-dependent energy sources1. Harnessing energy from nuclear fusion in a large reactor scale, however, still presents many scientific challenges despite the many years of research and steady advances in magnetic confinement approaches. State-of-the-art magnetic fusion devices cannot yet achieve a sustainable fusion performance, which requires a high temperature above 100 million kelvin and sufficient control of instabilities to ensure steady-state operation on the order of tens of seconds2,3. Here we report experiments at the Korea Superconducting Tokamak Advanced Research4 device producing a plasma fusion regime that satisfies most of the above requirements: thanks to abundant fast ions stabilizing the core plasma turbulence, we generate plasmas at a temperature of 100 million kelvin lasting up to 20 seconds without plasma edge instabilities or impurity accumulation. A low plasma density combined with a moderate input power for operation is key to establishing this regime by preserving a high fraction of fast ions. This regime is rarely subject to disruption and can be sustained reliably even without a sophisticated control, and thus represents a promising path towards commercial fusion reactors.

The MYB46/MYB83-mediated transcriptional regulatory programme is a gatekeeper of secondary wall biosynthesis.

BACKGROUND: The secondary cell wall is a defining feature of xylem cells and allows them to resist both gravitational forces and the tension forces associated with the transpirational pull on their internal columns of water. Secondary walls also constitute the majority of plant biomass. Formation of secondary walls requires co-ordinated transcriptional regulation of the genes involved in the biosynthesis of cellulose, hemicellulose and lignin. This co-ordinated control appears to involve a multifaceted and multilayered transcriptional regulatory programme. SCOPE: Transcription factor MYB46 (At5g12870) has been shown to function as a master regulator in secondary wall formation in Arabidopsis thaliana. Recent studies show that MYB46 not only regulates the transcription factors but also the biosynthesis genes for all of the three major components (i.e. cellulose, hemicellulose and lignin) of secondary walls. This review considers our current understanding of the MYB46-mediated transcriptional regulatory network, including upstream regulators, downstream targets and negative regulators of MYB46. CONCLUSIONS AND OUTLOOK: MYB46 is a unique transcription factor in that it directly regulates the biosynthesis genes for all of the three major components of the secondary wall as well as the transcription factors in the biosynthesis pathway. As such, MYB46 may offer a useful means for pathway-specific manipulation of secondary wall biosynthesis. However, realization of this potential requires additional information on the 'MYB46-mediated transcriptional regulatory programme', such as downstream direct targets, upstream regulators and interacting partners of MYB46.

Rotational resonance of nonaxisymmetric magnetic braking in the KSTAR tokamak.

One of the important rotational resonances in nonaxisymmetric neoclassical transport has been experimentally validated in the KSTAR tokamak by applying highly nonresonant n=1 magnetic perturbations to rapidly rotating plasmas. These so-called bounce-harmonic resonances are expected to occur in the presence of magnetic braking perturbations when the toroidal rotation is fast enough to resonate with periodic parallel motions of trapped particles. The predicted and observed resonant peak along with the toroidal rotation implies that the toroidal rotation in tokamaks can be controlled naturally in favorable conditions to stability, using nonaxisymmetric magnetic perturbations.

Superiority of conventional intensity-modulated radiotherapy over helical tomotherapy in locally advanced non-small cell lung cancer. A comparative plan analysis.

PURPOSE: To compare helical tomotherapy (HT) and conventional intensity-modulated radiotherapy (IMRT) using a variety of dosimetric and radiobiologic indexes in patients with locally advanced non-small cell lung cancer (LA-NSCLC). PATIENTS AND METHODS: A total of 20 patients with LA-NSCLC were enrolled. IMRT plans with 4-6 coplanar beams and HT plans were generated for each patient. Dose distributions and dosimetric indexes for the tumors and critical structures were computed for both plans and compared. RESULTS: Both modalities created highly conformal plans. They did not differ in the volumes of lung exposed to > 20 Gy of radiation. The average mean lung dose, volume receiving ≥ 30 Gy, and volume receiving ≥ 10 Gy in HT planning were 18.3 Gy, 18.5%, and 57.1%, respectively, compared to 19.4 Gy, 25.4%, and 48.9%, respectively, with IMRT (p = 0.004, p < 0.001, and p < 0.001). The differences between HT and IMRT in lung volume receiving ≥ 10-20 Gy increased significantly as the planning target volume (PTV) increased. For 6 patients who had PTV greater than 700 cm(3), IMRT was superior to HT for 5 patients in terms of lung volume receiving ≥ 5-20 Gy. The integral dose to the entire thorax in HT plans was significantly higher than in IMRT plans. CONCLUSION: HT gave significantly better control of mean lung dose and volume receiving ≥ 30-40 Gy, whereas IMRT provided better control of the lung volume receiving ≥ 5-15 Gy and the integral dose to entire thorax. In most patients with PTV greater than 700 cm(3), IMRT was superior to HT in terms of lung volume receiving ≥ 5-20 Gy. It is therefore advised that caution should be exercised when planning LA-NSCLC using HT.

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.

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.

Plasma total homocysteine and the methylenetetrahydrofolate reductase 677C>T polymorphism do not contribute to the distribution of cervico-cerebral atherosclerosis in ischaemic stroke patients.

OBJECTIVE: To evaluate the effects of plasma total homocysteine (tHcyt) and the MTHFR 677C>T polymorphism on determining the intracranial- (IC) and extracranial (EC) locations of atherosclerosis. METHODS: Brain MR angiography was performed on 463 patients with symptomatic ischaemic stroke to detect significant atherosclerosis (more than 50% stenosis of vessel diameter) in the IC- and EC arteries. Relationships between IC- or EC atherosclerosis and plasma tHcyt level and/or MTHFR 677C>T genotypes were analyzed after adjusting for vascular risk factors. RESULTS: The odd ratios (ORs) of plasma tHcyt were not significantly higher in patients with either IC- or EC atherosclerosis than in patients with no atherosclerosis. When the study subjects were stratified into three subgroups according to their plasma tHcyt levels, neither the crude ORs nor adjusted ORs of each IC- and EC atherosclerosis in highest and middle plasma tHcyt tertile were significantly different from those in lowest plasma tHcyt tertile. The ORs of the MTHFR 677TT genotype in IC- and EC atherosclerosis were not significantly different from those in no atherosclerosis. There was no dose-dependent effect of MTHFR 677T allele on either IC- or EC atherosclerosis. CONCLUSION: Plasma tHcyt level and the MTHFR 677C>T polymorphism do not contribute to the distribution of cervico-cerebral atherosclerosis in ischaemic stroke patients.

Bilateral cerebral hemispheric infarction associated with sildenafil citrate (Viagra) use.

Sildenafil citrate (Viagra) is one of the frequently prescribed drugs for men with erectile dysfunction. We describe a 52-year-old man with bilateral middle cerebral artery (MCA) territory infarction after sildenafil use. He ingested 100 mg of sildenafil and about 1 h later, he complained of chest discomfort, palpitation and dizziness followed by mental obtundation, global aphasia and left hemiparesis. Brain magnetic resonance imaging documented acute bilateral hemispheric infarction, and cerebral angiography showed occluded bilateral MCA. Despite significant bilateral MCA stenosis and cerebral infarction, systemic hypotension persisted for a day. We presume that cerebral infarction was caused by cardioembolism with sildenafil use.

Zero valent iron and clay mixtures for removal of trichloroethylene, chromium(VI), and nitrate.

A series of batch experiments on free swell, hydraulic conductivity, and contaminant removal efficiency was performed for the combination of bentonite and zero valent iron (ZVI), in order to identify the optimal mixing ratio between bentonite and ZVI. The swell volume of the bentonite-ZVI mixtures did not change with increasing ZVI, and the hydraulic conductivity decreased as the ZVI increased. The reduction rates and removal efficiencies of trichloroethylene (TCE), Chromium(VI), and nitrate increased as ZVI content increased, while there was no practical difference in removal efficiencies between 30% and 100% of ZVI weight contents. Therefore, 30% of the ZVI content was used as the optimal amount in this research since the physical properties, such as swell volume and hydraulic conductivity, as well as the contaminant sorption and reduction were the most efficient. From Raman spectrophotometer analysis, peaks of magnetite, maghemite, and hematite were observed on the surfaces of the bentonites that had been used for the mixtures. Since iron oxides are strong adsorbers of contaminants and magnetites can facilitate the electron transfer of irons, these formations are beneficial for the long-term performance of the iron metals.

Intracranial hemorrhage associated with idiopathic thrombocytopenic purpura: report of seven patients and a meta-analysis.

We present the results of a meta-analysis using clinical data obtained from seven of our patients and 24 previously reported patients with idiopathic thrombocytopenic purpura complicated by intracranial hemorrhage. Twenty-four had an intracerebral hemorrhage (ICH) and seven had a subdural hematoma (SDH). Mean age of the patients with ICH was significantly younger than those with SDH. The mortality rate of ICH associated with ITP was similar to that of spontaneous ICH. All seven patients with SDH improved without sequelae.

Spasmodic dysphonia associated with a left ventrolateral putaminal lesion.

A 34-year-old man presented with a 30-year history of spasmodic dysphonia. He developed a speech disturbance 1 month after a closed head injury due to a fall. Sighing, coughing, and crying were normal. He had a tremor of the right hand when he drew a vertical line. His out-stretched right hand had a minimal dystonic posture with occasional jerks of the fingers. T1-weighted axial brain MRI study showed a low signal intensity lesion at the putamen; coronal and axial T2-weighted MRI brain scans showed a high and low signal intensity lesion confined to the middle part of the ventrolateral putamen. Damage to the ventrolateral putamen may have caused abnormal voluntary control of the laryngeal muscles.

Radiation treatment in patients with recurrent Kimura's disease.

PURPOSE: To assess the benefits of radiotherapy for patients with recurrent Kimura's disease and to document the role of radiation treatment as a successful mode of therapy. METHODS AND MATERIALS: From 1985 to 1991, a total of 26 patients with Kimura's disease were treated by local excision and/or systemic steroids at Yonsei University, Yonsei Cancer Center Hospital. Seventeen patients among them eventually had local recurrence after surgical excision. The 17 patients with recurrent Kimura's disease were divided into two groups on the basis of those who received radiation treatment and those who did not. Eight patients in the nonradiation group were treated by systemic steroids alone with individualized doses and schedules. The remaining nine patients in the radiation group were treated by external beam irradiation. The prescribed radiation doses varied from 21.6 to 45 Gy. A comparative analysis on treatment results between both groups was undertaken retrospectively. RESULTS: The majority of the recurrent cases in the nonradiation group treated by steroids alone experienced rapid rerecurrence of the disease. In contrast, all of the patients except one case in the radiation group achieved excellent local control with moderate doses of radiation. There was a significant difference in the rerecurrence rate between the patients of the radiation group (11%) and the nonradiation group (75%). No clear dose-response relationship could be derived from the patients of the radiation group. No secondary malignancies in the irradiated areas have been observed. CONCLUSION: Our results suggest that radiation treatment is preferable as an alternative option for patients with recurrent Kimura's disease who have failed to achieve local control by other modalities.

Isolation of peptide ligands that inhibit glutamate racemase activity from a random phage display library.

Several new antibacterial agents are currently being developed in response to the emergence of bacterial resistance to existing antibiotic substances. The new agents include compounds that interfere with bacterial membrane function. The peptidoglycan component of the bacterial cell wall is synthesized by glutamate racemase, and this enzyme is responsible for the biosynthesis of d-glutamate, which is an essential component of cell wall peptidoglycan. In this study, we screened a phage display library expressing random dodecapeptides on the surface of bacteriophage against an Escherichia coli glutamate racemase, and isolated specific peptide sequences that bind to the enzyme. Twenty-seven positive phage clones were analyzed, and seven different peptide sequences were obtained. Among them, the peptide sequence His-Pro-Trp-His-Lys-Lys-His-Pro-Asp-Arg-Lys-Thr was found most frequently, suggesting that this peptide might have the highest affinity to glutamate racemase. The positive phage clones and HPWHKKHPDRKT synthetic peptide were able to inhibit glutamate racemase activity in vitro, implying that our peptide inhibitors may be utilized for the molecular design of new potential antibacterial agents targeting cell wall synthesis.

Reciprocal inhibition between the forearm muscles in patients with paroxysmal kinesigenic dyskinesia.

We measured the changes of forearm flexor H reflexes produced by conditioning radial nerve stimulation at delays of -2, 0, 2, 4, 7.5, 10, 25 and 75 ms in 10 patients with PKD and six with generalized seizure disorder. We compared the results with 12 normal volunteers. In the patients with PKD, we compared the amounts of reciprocal inhibition between the severely and the asymptomatic or mildly affected sides of arms. Follow-up studies were done in eight PKD patients after they responded to the anticonvulsant treatment. At each delay, patients with seizure disorders showed comparable amounts of changes with controls. Patients with PKD showed paradoxical facilitation at a delay of 0 ms, enhanced facilitation between 2 to 7.5 ms delays and attenuated inhibition at a delay of 75 ms. There were no significant differences in the amount of reciprocal inhibition according to the severity of clinical symptoms. Follow-up studies showed no significant changes of reciprocal inhibition compared to the baseline data. In PKD, paradoxical facilitation and enhanced first relative facilitation period may be caused by defective spinal interneurons. In addition to the defective reciprocal inhibition, abnormalities of supraspinal inputs seem to be involved in the genesis of PKD.

Failure of treatment of ununited fractures of the carpal scaphoid. The role of non-compliance.

We studied the results in thirty patients who had grafting of an ununited fracture of the carpal scaphoid bone. Psychiatric evaluations revealed that the thirteen patients who had a non-union of the initial scaphoid bone graft had significant psychiatric problems, whereas the seventeen patients in whom the non-union had healed after initial bone-grafting of the scaphoid did not have psychiatric abnormalities. Technically successful surgical revisions in the first group of patients did not result in significant clinical improvement. We concluded that most failures of the bone grafts were related to non-compliance on the part of the patient and that some of the operations could have been avoided if the underlying psychiatric problems had been recognized preoperatively.

Locked-in syndrome with bilateral peduncular infarct.

Locked-in syndrome due to midbrain infarct is very rare. This report describes a patient with locked-in syndrome whose magnetic resonance images showed bilateral infarcts in the cerebral peduncle. Cerebral angiography disclosed bilateral irregular thrombotic narrowing of the vertebral and proximal basilar arteries with rostral basilar artery occlusion, a previously unreported findings.

Effects of screw types in cementless fixation of tibial tray implants: stability and strength assessment.

OBJECTIVE: To test the stability and strength of tibial trays fixed with cortical screws and tibial trays fixed with cancellous screws under axial and anterior-posterior shear loading conditions. DESIGN: Five matched human fresh frozen cadaver knees without prior pathology were used as paired specimens for comparison of cortical to cancellous screw fixation of tibial trays. BACKGROUND: Current cementless fixation of tibial trays in total knee arthroplasty is obtained by using a combination of stems, keels, posts, pegs, and screws. To date there has been no study comparing isolated cortical and cancellous screw fixation in cementless arthroplasty. METHODS: An Instron machine and a video digitizing system were used to examine tibial tray lift-off, subsidence, and anterior-posterior load to failure at the bone-implant interface in five matched pairs of knees and compare the difference between cancellous and cortical screw fixation. RESULTS: Non-destructive cyclic testing showed a significant difference between the two types of screws for tibial tray subsidence with cancellous fixation greater than cortical (P < 0.05), but not for lift-off (P > 0.05). Load to failure testing in anterior-posterior direction did not result in a significant difference between the two types of screws for initial stiffness and ultimate load (P > 0.05), but did result in a significant difference of energy absorbed to failure (P < 0.01). CONCLUSIONS: The difference in amount of subsidence between cortical and cancellous fixation could possibly be due to microfractures of the underlying trabecular bone with cancellous fixation. Neither screw type was able to completely fix the tibial tray to bone and prevent micromotion. Although the load at failure for anterior-posterior shear was similar for the two screw types, the energy absorbed was greater for the cortical screws which may be a result of additional strength provided by the cortical bone surrounding the screw.

Preliminary report on usefulness of magnetic resonance imaging for outcome prediction in early-stage Legg-Calvé-Perthes disease.

The usefulness of magnetic resonance imaging (MRI) for predicting prognosis was evaluated in 11 patients with unilateral early-stage Legg-Calvé-Perthes disease who were treated with a non-weight-bearing abduction brace. Six to 10 months after disease onset, severity of cartilage hypertrophy and physeal curvature of the femoral head were scored on MRI. Femoral head deformity was radiographically evaluated. Among five patients whose MRI score was 8 or greater, radiographic evaluation after the treatment was "poor" or "fair," whereas evaluation for the other six patients whose MRI score was 7 or less was "good." The MRI scores indicated possible occurrence of femoral head deformation. Treatment method should be considered carefully when the MRI score is high.