Dynamic Stark spectroscopic measurements of microwave electric fields inside the plasma near a high-power antenna.

Fully dynamic Stark effect visible spectroscopy was used for the first time to directly measure the local rf electric field in the boundary plasma near a high-power antenna in high-performance, magnetically confined, fusion energy experiment. The measurement was performed in the superconducting tokamak Tore Supra, in the near field of a 1­3 MW, lower-hybrid, 3.7 GHz wave-launch antenna, and combined with modeling of neutral atom transport to estimate the local rf electric field amplitude (as low as 1­2 kV/cm) and direction in this region. The measurement was then shown to be consistent with the predicted values from a 2D full-wave propagation model. Notably the measurement confirmed that the electric field direction deviates substantially from the direction in which it is launched by the waveguides as it penetrates only a few cm radially inward into the plasma from the waveguides, consistent with the model.

First results from the implementation of the ITER diagnostic residual gas analyzer prototype at Wendelstein 7-X.

Fusion reactors and long pulse fusion experiments heavily depend on a continuous fuel cycle, which requires detailed monitoring of exhaust gases. We have used a diagnostic residual gas analyzer (DRGA) built as a prototype for ITER and integrated it on the most advanced stellarator fusion experiment, Wendelstein 7-X (W7-X). The DRGA was equipped with a sampling tube and assessed for gas time of flight sample response, effects of magnetic field on gas detection and practical aspects of use in a state of the art fusion environment. The setup was successfully commissioned and operated and was used to observe the gas composition of W7-X exhaust gases. The measured time of flight gas response was found to be in the order of a second for a 7 m sample tube. High values of magnetic field were found to affect the partial pressure readings of the DRGA and suggest that additional shielding is necessary in future experimental campaigns.

Visible spectroscopy diagnostics for tungsten source assessment in the WEST tokamak: First measurements.

The present work concerns the measurements obtained with the Tungsten (W) Environment in Steady-state Tokamak (WEST) visible spectroscopy system during the first experimental campaign. This system has been developed in the framework of the WEST project that equipped the existing Tore Supra device with a tungsten divertor in order to test actively cooled tungsten Plasma Facing Components (PFC) in view of preparing for ITER operation. The goal of this diagnostic is to measure the PFC sources and the deuterium recycling with spectral, spatial, and temporal resolution adapted to the predicted power deposition profiles on the objects observed. Three kinds of PFCs are monitored: the Ion Cyclotron Resonance Heating (ICRH) antenna and Low Hybrid Current Drive (LHCD) launcher W limiters; one of the 6 W inner bumpers; and the upper and lower W divertors. Large-aperture in-vessel actively cooled optical systems (f-number ∼ 3) were installed for each view and connected to optical fibres. A total of 240 optical fibers can be distributed on various detection systems including a fast response-time, multi-channel, filtered photodetector-based "Filterscope" system, developed by Oak Ridge National Laboratory (USA) as well as grating spectrometers optimized for multi-sightline analysis. The first WEST experimental campaign conducted in 2017 has been dedicated to plasma start-up development during which the visible spectroscopy system has provided crucial information related to the impurity content first and then impurity sources. The diagnostic setup for that first experimental campaign was limited to the inner bumper and outer limiters but was sufficient to demonstrate that the optical setup was in accordance with the specifications. The radiance calibration procedure allowed us to estimate fluxes from the main limiter of about 8 × 1018 atoms/(s m2) and to show a first W source radial profile along the outboard limiter.

Development of visible spectroscopy diagnostics for W sources assessment in WEST.

The present work concerns the development of a W sources assessment system in the framework of the tungsten-W environment in steady state tokamak project that aims at equipping the existing Tore Supra device with a tungsten divertor in order to test actively cooled tungsten Plasma Facing Components (PFCs) in view of preparing ITER operation. The goal is to assess W sources and D recycling with spectral, spatial, and temporal resolution adapted to the PFCs observed. The originality of the system is that all optical elements are installed in the vacuum vessel and compatible with steady state operation. Our system is optimized to measure radiance as low as 1016 Ph/(m2 s sr). A total of 240 optical fibers will be deployed to the detection systems such as the "Filterscope," developed by Oak Ridge National Laboratory (USA) and consisting of photomultiplier tubes and filters, or imaging spectrometers dedicated to Multiview analysis.

Overview of diagnostic performance and results for the first operation phase in Wendelstein 7-X (invited).

Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters in December 2015. At the end of the 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were in operation, allowing detailed studies of many interesting plasma phenomena. For example, fast neutral gas manometers supported by video cameras (including one fast-frame camera with frame rates of tens of kHz) as well as visible cameras with different interference filters, with field of views covering all ten half-modules of the stellarator, discovered a MARFE-like radiation zone on the inboard side of machine module 4. This structure is presumably triggered by an inadvertent plasma-wall interaction in module 4 resulting in a high impurity influx that terminates some discharges by radiation cooling. The main plasma parameters achieved in OP1.1 exceeded predicted values in discharges of a length reaching 6 s. Although OP1.1 is characterized by short pulses, many of the diagnostics are already designed for quasi-steady state operation of 30 min discharges heated at 10 MW of ECRH. An overview of diagnostic performance for OP1.1 is given, including some highlights from the physics campaigns.

Crystallization and preliminary X-ray analysis of the periplasmic dipeptide binding protein from Escherichia coli.

The periplasmic dipeptide-binding protein from Escherichia coli has been purified, freed of bound endogenous ligands, and crystallized. Crystals of the protein in complex with added dipeptides have been subjected to X-ray analysis. The crystals grow as hexagonal bipyramids or eye-shaped disks which have the symmetry of space group P6(1). The unit cell dimensions are a = b = 183 A, c = 212 A, and the diffraction pattern extends to 3.2 A resolution with a conventional X-ray source.

Diagnostic radiology. One week prelude to the clinical continuum.

A one-week comprehensive program of diagnostic radiology was presented to 205 junior medical students just entering the clinical phase of their education. Course objectives were to familiarize the students with the various imaging modalities and their application to common clinical situations and to introduce an organized approach to interpretation of conventional radiographs. This course's one-week time frame was unique. Various educational activities were employed to allow the large number of students to participate actively in the educational process and to enable them to cope with the intensive presentation of unfamiliar vocabulary, materials, and modalities. Through this course, the students achieved an understanding of the impact of radiologic findings on clinical situations and of the necessity of designing an orderly radiologic workup tailored to patient needs and clinical presentation. Most importantly, they gained a functional knowledge of the decision-making process involved in radiology as well as in clinical medicine.

The current status of faculty staffing and resident training in emergency radiology. Results of a survey.

The results of a survey of United States and Canadian radiology residency programs in hospitals maintaining major emergency departments indicate that (1) radiologic faculty assignment to emergency medicine may include "all faculty," "specific faculty," "specific and other faculty," "general," and "musculoskeletal" faculty; (2) a chief of emergency radiology section is designated in less than 35% of radiology departments providing emergency room services; (3) radiology resident rotation in emergency radiology occurs in less than 2/3 of the surveyed programs; and (4) radiology resident experience in emergency radiology ranges from two to 16 weeks in 40% of these programs, the remainder being "unspecified." The effect of this circumstance upon the emergency department patient care and resident teaching in emergency radiology is discussed and remedial suggestions presented.

Anterior subluxation of the cervical spine: hyperflexion sprain.

Anterior subluxation (hyperflexion sprain) is localized, purely ligamentous disruption of the cervical spine caused by a limited flexion force. When associated with a simple wedge fraction, also a flexion injury, anterior subluxation may be the more significant lesion. Radiographically, anterior subluxation is characterised by (1) a localized kyphotic angulation at the level of injury; (2) anterior rotation, or displacement, of the subluxed vertebra; (3) anterior narrowing and posterior widening of the disc space; (4) widening of the space between the subluxed vertebral body and the subjacent articular masses; (5) displacement of the inferior articulating facets of the subluxed vertebra with respect to their contiguous subjacent facets; and (6) widening of the interspinous space ("fanning"). The localized kyphotic angulation at the level of ligamentous disruption distinguishes pathologic anterior subluxation from diffuse "reversal of the normal cervical lordosis"; produced by voluntary positioning or muscle spasm. Anterior subluxation is clinically significant because of the approximate 20% incidence of delayed instability due to impaired ligamentous healing.

The importance of soft tissues in certain skeletal traumatic lesions.

Soft tissue aspects of skeletal trauma are discussed according to two categories: (1) those injuries in which the significance of the soft tissue in the pathophysiology of the skeletal lesion is indicated by the characteristics of the skeletal injury (such as extension teardrop fracture, little leaguer's elbow, "baseball fracture," and Bennett's fracture); and (2) those injuries in which the associated soft tissue injury, or complication, may be reasonably inferred by the location and nature of the skeletal injury (such as major facial fractures, posterior sternoclavicular dislocations, fractures of the lower rib and lumbar transverse processes, and pelvic disruptions).

Effect of phenytoin on functional recovery after experimental spinal cord injury in dogs.

We injured 26 dogs by dropping a 25-g, flat-bottomed weight directly onto the exposed dura. Dogs treated with phenytoin (PHT) were clinically superior to untreated controls when compared 6 weeks after injury. Comparison between PHT and dexamethasone reveals that PHT is at least as effective. The therapeutic effectiveness of PHT treatment begun immediately after injury and begun 30 minutes later was evaluated. The results obtained in all three treated groups of dogs were superior to the results with untreated controls at a significance level of P < 0.01.

Computed tomography-guided intracranial biopsy and cyst aspiration.

A coordinated series of instruments has been developed for use in computed tomography (CT)-guided brain lesion biopsy and cyst aspiration: a plastic guide needle that is relatively free of CT artifacts, a ball-and-socket holding device for multidirectional sampling, and an aspiration-cutting biopsy needle that reliably produces consistent cores of tissue. Twenty-six biopsy and/or aspiration procedures have been performed on 24 patients with an overall biopsy success rate of 79%. The method is most reliable with highly malignant astrocytomas and least reliable with metastases and unusual primary tumors. There were 3 complications: 2 intratumoral hematomas and 1 death due to hemorrhage. A survey of published CT biopsy series shows an overall success rate of 85%. The rate of serious complications is 3.5% (including 3 deaths). The incidence of intratumoral hematomas that are clinically silent or associated with relatively minor clinical problems is 9%. CT-guided intracranial biopsy is more reliable than the earlier freehand methods and simpler than stereotactic techniques. It is the procedure of choice for percutaneous biopsy of superficial and deep hemispheric lesions.

Magnetic resonance imaging of hyperbaric oxygen treated rats with spinal cord injury: preliminary studies.

Magnetic resonance imaging (MRI) has been performed to assess the efficacy of hyperbaric oxygen (HBO) treatment on experimental spinal cord injury in a rat animal model. A moderately severe injury, similar to Type III injury seen in humans (Kulkarni et al. Radiology 164:837;1987) has been chosen for these studies. An improvement in the neurologic recovery (based on Tarlov scale) has been observed following HBO treatment over a period of 72 hr. Based on MRI, HBO treatment appears to arrest the spread of hemorrhage and resolve edema.

Acute spinal cord injury. A study using physical examination and magnetic resonance imaging.

Magnetic resonance imaging (MRI) was performed on 37 patients with acute spinal injury using T1- and T2-weighted images. Three different types of MRI signal patterns were detected in association with these spinal cord injuries. A classification was developed using these three patterns. Type I, seen in ten (27.0%) of the patients, demonstrated a decreased signal intensity consistent with acute intraspinal hemorrhage. Type II, seen in 16 (43.2%) of the patients, demonstrated a bright signal intensity consistent with acute cord edema. Type III, seen in three (8.1%) of the patients, demonstrated a mixed signal of hypointensity centrally and hyperintensity peripherally consistent with contusion. The remaining eight patients had normal cords by MRI. All 37 patients had an admitting neurologic assessment and classification of their spinal injury according to the Frankel classification and the Trauma Motor Index (TMI). At an average of 12.1 months postinjury, their neurologic function was reassessed. Patients with Type I patterns showed no improvement in their Frankel classification and minimal improvement in their TMI, 32.1 to 42.4. In comparison, all of the Type II and III patterns improved at least one Frankel classification. The Type II TMI increased from 70.8 to 91.9 and Type III from 37.3 to 75.7. This preliminary report indicates a distinct correlation between the pattern of spinal cord injury as identified by MRI and neurologic recovery. It appears that the ability of MRI to aid in examination of the condition of the spinal cord will offer a means of predicting neurologic recovery following acute spinal cord injury.

Histopathologic correlation of magnetic resonance imaging signal patterns in a spinal cord injury model.

Magnetic resonance imaging (MRI) provides a noninvasive method of monitoring the pathologic response to spinal cord injury. Specific MR signal intensity patterns appear to correlate with degrees of improvement in the neurologic status in spinal cord injury patients. Histologic correlation of two types of MR signal intensity patterns are confirmed in the current study using a rat animal model. Adult male Sprague-Dawley rats underwent spinal cord trauma at the midthoracic level using a weight-dropping technique. After laminectomy, 5- and 10-gm brass weights were dropped from designated heights onto a 0.1-gm impounder placed on the exposed dura. Animals allowed to regain consciousness demonstrated variable recovery of hind limb paraplegia. Magnetic resonance images were obtained from 2 hours to 1 week after injury using a 2-tesla MRI/spectrometer. Sacrifice under anesthesia was performed by perfusive fixation; spinal columns were excised en bloc, embedded, sectioned, and observed with the compound light microscope. Magnetic resonance axial images obtained during the time sequence after injury demonstrate a distinct correlation between MR signal intensity patterns and the histologic appearance of the spinal cord. Magnetic resonance imaging delineates the pathologic processes resulting from acute spinal cord injury and can be used to differentiate the type of injury and prognosis.

Hyperextension-dislocation of the cervical spine. Ligament injuries demonstrated by magnetic resonance imaging.

We reviewed the magnetic resonance (MR) images of eight adults with acute hyperextension-dislocation of the cervical spine. The images were obtained to evaluate damage to the spinal cord. All eight patients had disruption of the anterior longitudinal ligament and of the annulus of the intervertebral disc, and separation of the posterior longitudinal ligament from the subjacent vertebra. Some, but not all, showed widening of the disc space, posterior bulging or herniation of the nucleus pulposus, and disruption of the ligamentum flavum. The MR demonstration of these ligament injuries, taken with the clinical and radiographic findings, establishes the mechanism of hyperextension-dislocation, confirms the diagnosis, and is relevant to management.

Radiographic evaluation of spinal trauma.

This article reviews the general principles that apply to the radiographic evaluation of acute injury of the cervical and thoracolumbar spine and discusses the possible use of various imaging techniques.

A practical classification of acute cervical spine injuries.

This article presents a practical classification of acute cervical spine injuries based on terminology with generally accepted and understood definitions, published results of experimentally produced acute injuries of the cervical spine, and the correlation of the radiographic and pathologic characteristics of the laboratory models with acute clinical injuries.

Injury to the glenoid fossa.

An illustrated case of fracture through the confines of the glenoid fossa by the mandibular condyle is presented. The mechanism of injury and postinjury sequelae of this rarely reported but frequently suspected occurrence are discussed and a treatment rationale proposed. The key to the diagnosis of this entity is an awareness of vector forces directed to the region of the glenoid fossa with or without evidence of subcondylar fracture.

Posterior hip dislocation associated with acute traumatic injury of the thoracic aorta: a previously unrecognized injury complex.

Posterior hip dislocation associated with acute injury to the thoracic aorta is a previously unrecognized injury complex. This study reveals that 8% of patients with posterior hip dislocation have associated injury to the thoracic aorta because of abrupt deceleration injuries. This study defines the association of traumatic posterior hip dislocation and acute traumatic injury of the thoracic aorta, describes the mechanism of injury, and discusses the evaluation of a patient with a suspected acute traumatic aortic injury.