Plasmoid Formation and Strong Radiative Cooling in a Driven Magnetic Reconnection Experiment.

We present the first experimental study of plasmoid formation in a magnetic reconnection layer undergoing rapid radiative cooling, a regime relevant to extreme astrophysical plasmas. Two exploding aluminum wire arrays, driven by the Z machine, generate a reconnection layer (S_{L}≈120) in which the cooling rate far exceeds the hydrodynamic transit rate (τ_{hydro}/τ_{cool}>100). The reconnection layer generates a transient burst of >1 keV x-ray emission, consistent with the formation and subsequent rapid cooling of the layer. Time-gated x-ray images show fast-moving (up to 50 km s^{-1}) hotspots in the layer, consistent with the presence of plasmoids in 3D resistive magnetohydrodynamic simulations. X-ray spectroscopy shows that these hotspots generate the majority of Al K-shell emission (around 1.6 keV) prior to the onset of cooling, and exhibit temperatures (170 eV) much greater than that of the plasma inflows and the rest of the reconnection layer, thus providing insight into the generation of high-energy radiation in radiatively cooled reconnection events.

Performance Scaling in Magnetized Liner Inertial Fusion Experiments.

We present experimental results from the first systematic study of performance scaling with drive parameters for a magnetoinertial fusion concept. In magnetized liner inertial fusion experiments, the burn-averaged ion temperature doubles to 3.1 keV and the primary deuterium-deuterium neutron yield increases by more than an order of magnitude to 1.1×10^{13} (2 kJ deuterium-tritium equivalent) through a simultaneous increase in the applied magnetic field (from 10.4 to 15.9 T), laser preheat energy (from 0.46 to 1.2 kJ), and current coupling (from 16 to 20 MA). Individual parametric scans of the initial magnetic field and laser preheat energy show the expected trends, demonstrating the importance of magnetic insulation and the impact of the Nernst effect for this concept. A drive-current scan shows that present experiments operate close to the point where implosion stability is a limiting factor in performance, demonstrating the need to raise fuel pressure as drive current is increased. Simulations that capture these experimental trends indicate that another order of magnitude increase in yield on the Z facility is possible with additional increases of input parameters.

Experimental Demonstration of the Stabilizing Effect of Dielectric Coatings on Magnetically Accelerated Imploding Metallic Liners.

Enhanced implosion stability has been experimentally demonstrated for magnetically accelerated liners that are coated with 70 µm of dielectric. The dielectric tamps liner-mass redistribution from electrothermal instabilities and also buffers coupling of the drive magnetic field to the magneto-Rayleigh-Taylor instability. A dielectric-coated and axially premagnetized beryllium liner was radiographed at a convergence ratio [CR=Rin,0/Rin(z,t)] of 20, which is the highest CR ever directly observed for a strengthless magnetically driven liner. The inner-wall radius Rin(z,t) displayed unprecedented uniformity, varying from 95 to 130 µm over the 4.0 mm axial height captured by the radiograph.

Experimental demonstration of fusion-relevant conditions in magnetized liner inertial fusion.

This Letter presents results from the first fully integrated experiments testing the magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)], in which a cylinder of deuterium gas with a preimposed 10 Taxial magnetic field is heated by Z beamlet, a 2.5 kJ, 1 TW laser, and magnetically imploded by a 19 MA, 100 ns rise time current on the Z facility. Despite a predicted peak implosion velocity of only 70 km = s, the fuel reaches a stagnation temperature of approximately 3 keV, with T(e) ≈ T(i), and produces up to 2 x 10(12) thermonuclear deuterium-deuterium neutrons. X-ray emission indicates a hot fuel region with full width at half maximum ranging from 60 to 120 µm over a 6 mm height and lasting approximately 2 ns. Greater than 10(10) secondary deuterium-tritium neutrons were observed, indicating significant fuel magnetization given that the estimated radial areal density of the plasma is only 2 mg = cm(2).

Understanding fuel magnetization and mix using secondary nuclear reactions in magneto-inertial fusion.

Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs.

Observations of modified three-dimensional instability structure for imploding z-pinch liners that are premagnetized with an axial field.

Novel experimental data are reported that reveal helical instability formation on imploding z-pinch liners that are premagnetized with an axial field. Such instabilities differ dramatically from the mostly azimuthally symmetric instabilities that form on unmagnetized liners. The helical structure persists at nearly constant pitch as the liner implodes. This is surprising since, at the liner surface, the azimuthal drive field presumably dwarfs the axial field for all but the earliest stages of the experiment. These fundamentally 3D results provide a unique and challenging test for 3D-magnetohydrodynamics simulations.

Demonstration of improved laser preheat with a cryogenically cooled magnetized liner inertial fusion platform.

We report on progress implementing and testing cryogenically cooled platforms for Magnetized Liner Inertial Fusion (MagLIF) experiments. Two cryogenically cooled experimental platforms were developed: an integrated platform fielded on the Z pulsed power generator that combines magnetization, laser preheat, and pulsed-power-driven fuel compression and a laser-only platform in a separate chamber that enables measurements of the laser preheat energy using shadowgraphy measurements. The laser-only experiments suggest that ∼89% ± 10% of the incident energy is coupled to the fuel in cooled targets across the energy range tested, significantly higher than previous warm experiments that achieved at most 67% coupling and in line with simulation predictions. The laser preheat configuration was applied to a cryogenically cooled integrated experiment that used a novel cryostat configuration that cooled the MagLIF liner from both ends. The integrated experiment, z3576, coupled 2.32 ± 0.25 kJ preheat energy to the fuel, the highest to-date, demonstrated excellent temperature control and nominal current delivery, and produced one of the highest pressure stagnations as determined by a Bayesian analysis of the data.

Investigation of high-temperature bright plasma X-ray sources produced in 5-MA X-pinch experiments.

Using solid, machined X-pinch targets driven by currents rising from 0 to 5-6 MA in 60 ns, we observed bright spots of 5-9-keV continuum radiation from 5±2-µm diameter regions. The >6-keV radiation is emitted in about 0.4 ns, and the bright spots are roughly 75 times brighter than the bright spots measured at 1 MA. A total x-ray power of 10 TW peak and yields of 165±20 kJ were emitted from a 3-mm height. The 3-5-keV continuum radiation had a 50-90-GW peak power and 0.15-0.35-kJ yield. The continuum is plausibly from a 1275±75-eV blackbody or alternatively from a 3500±500-eV bremsstrahlung source.

Penetrating radiography of imploding and stagnating beryllium liners on the Z accelerator.

The implosions of initially solid beryllium liners (tubes) have been imaged with penetrating radiography through to stagnation. These novel radiographic data reveal a high degree of azimuthal correlation in the evolving magneto-Rayleigh-Taylor structure at times just prior to (and during) stagnation, providing stringent constraints on the simulation tools used by the broader high energy density physics and inertial confinement fusion communities. To emphasize this point, comparisons to 2D and 3D radiation magnetohydrodynamics simulations are also presented. Both agreement and substantial disagreement have been found, depending on how the liner's initial outer surface finish was modeled. The various models tested, and the physical implications of these models are discussed. These comparisons exemplify the importance of the experimental data obtained.

A 7.2 keV spherical x-ray crystal backlighter for two-frame, two-color backlighting at Sandia's Z Pulsed Power Facility.

Many experiments on Sandia National Laboratories' Z Pulsed Power Facility-a 30 MA, 100 ns rise-time, pulsed-power driver-use a monochromatic quartz crystal backlighter system at 1.865 keV (Si Heα) or 6.151 keV (Mn Heα) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array z-pinch. The x-ray source is generated by the Z-Beamlet laser, which provides two 527-nm, 1 kJ, 1-ns laser pulses. Radiographs of imploding, thick-walled beryllium liners at convergence ratios CR above 15 [CR=ri(0)/ri(t)] using the 6.151-keV backlighter system were too opaque to identify the inner radius ri of the liner with high confidence, demonstrating the need for a higher-energy x-ray radiography system. Here, we present a 7.242 keV backlighter system using a Ge(335) spherical crystal with the Co Heα resonance line. This system operates at a similar Bragg angle as the existing 1.865 keV and 6.151 keV backlighters, enhancing our capabilities for two-color, two-frame radiography without modifying the system integration at Z. The first data taken at Z include 6.2-keV and 7.2-keV two-color radiographs as well as radiographs of low-convergence (CR about 4-5), high-areal-density liner implosions.

The effects of ziprasidone on regional c-Fos expression in the rat forebrain.

RATIONALE: Typical and atypical antipsychotic drugs produce characteristic patterns of immediate early gene expression in rat forebrain that are considered to reflect their effects in schizophrenia subjects. OBJECTIVE: To use c-Fos immunohistochemistry to investigate the functional neuroanatomical profile of the newly introduced atypical agent ziprasidone. MATERIALS AND METHODS: c-Fos immunohistochemistry was performed on paraformaldehyde-fixed cryosections of rat brains obtained, initially, from animals 2, 4, or 6 h after oral administration of 10 mg/kg ziprasidone or vehicle and, subsequently, from animals 2 h after oral administration of 1, 3, or 10 mg/kg ziprasidone or vehicle. The density of immunoreactive nuclei was assessed in pre-determined forebrain regions. RESULTS: Ziprasidone induced a time-dependent increase in the density of c-Fos-positive nuclei that was maximal at 2 h. At the 2 h time-point, c-Fos expression was significantly (p<0.05) elevated in the shell and core of the nucleus accumbens, lateral and medial caudate putamen, and lateral septum. At 4 h post-dose, c-Fos expression was also significantly increased in the cingulate gyrus. Ziprasidone-induced c-Fos expression was dose-dependent with significant (p<0.05) c-Fos expression observed in the nucleus accumbens (shell and core) and caudate putamen (lateral and medial) at 3 and 10 mg/kg and in the lateral septum at 10 mg/kg. CONCLUSIONS: Increased c-Fos expression in the nucleus accumbens and lateral septum is considered to be predictive of activity against positive symptoms, in the caudate putamen of motor side effect liability, and in the cingulate gyrus of efficacy against negative symptoms. Thus, the observed pattern of c-Fos expression induced in rat brain by ziprasidone is consistent with its reported clinical effects, namely, efficacy against positive symptoms with a therapeutic window over motor side effects and with some activity against negative symptoms.

Normal bronchial epithelial cell expression of glutathione transferase P1, glutathione transferase M3, and glutathione peroxidase is low in subjects with bronchogenic carcinoma.

Normal bronchial epithelial cells (NBECs) are at risk for damage from inhaled and endogenous oxidative species and from epoxide metabolites of inhaled polycyclic aromatic hydrocarbons. Epidemiological and in vitro data suggest that interindividual variation in this risk may result from variation in NBEC expression of enzymes that inactivate reactive species by conjugating them to glutathione. Quantitative competitive reverse transcription-PCR was used to measure mRNA levels of glutathione transferases (GSTs) and glutathione peroxidases (GSHPxs) in primary NBECs from subjects with or without bronchogenic carcinoma. Mean expression levels (mRNA/10(3) beta-actin mRNA) in NBECs from 23 subjects without bronchogenic carcinoma compared to those from 11 subjects with bronchogenic carcinoma respectively (in parentheses) were: mGST (26.0, 6.11), GSTM3 (0.29, 0.09), combined GSTM1,2,4,5 (0.98, 0.60), GSTT1 (0.84, 0.76), GSTP1 (287, 110), GSHPx (140, 62.1), and GSHPxA (0.43, 0.34). Levels of GSTP1, GSTM3, and GSHPx were significantly (P < 0.05) lower in NBECs from subjects with bronchogenic carcinoma. Further, the gene expression index formed by multiplying the values for mGST x GSTM3 x GSHPx x GSHPxA x GSTP1 had a sensitivity (90%) and specificity (76%) for detecting NBECs from bronchogenic carcinoma subjects that was better than any individual gene. In cultured NBECs derived from eight individuals without bronchogenic carcinoma and incubated under identical conditions such that environmental effects were minimized, the mean level of expression and degree of interindividual variation for each gene evaluated was less than that observed in primary NBECs. Data from these studies support the hypotheses that (a) interindividual variation in risk for bronchogenic carcinoma results in part from interindividual variation in NBEC expression of antioxidant genes; (b) gene expression indices will better identify individuals at risk for bronchogenic carcinoma than individual gene expression values; and (c) both hereditary and environmental exposures contribute to the level of and interindividual variation in gene expression observed in primary NBECs. Many epidemiological studies have been designed to evaluate risk associated with polymorphisms or gene expression levels of putative susceptibility genes based on measurements in surrogate tissues, such as peripheral blood lymphocytes. Based on data presented here, it will be important to include the assessment of NBECs in future studies. Measurement of antioxidant gene expression in NBECs may identify the 5-10% of individuals at risk for bronchogenic carcinoma. Bronchoscopic sampling of NBECs from smokers and ex-smokers then will allow susceptible individuals to be entered into surveillance and/or chemoprevention studies.

Antiparkinsonian efficacy of a novel transdermal delivery system for (+)-PHNO in MPTP-treated squirrel monkeys.

We examined the ability of the antiparkinsonian agent (+)-4-propyl-9-hydroxynaphthoxazine (PHNO) to enter the systemic circulation in therapeutic concentrations after continuous transdermal absorption in squirrel monkeys rendered parkinsonian by MPTP. Direct subcutaneous administration of (+)-PHNO in the dose range of 2.5 to 20 micrograms/kg restored locomotor activity to levels seen in normal monkeys for approximately 1 hour. Application of transdermal patches capable of delivering, into an infinite sink, an estimated 2.6 micrograms/cm2/h of (+)-PHNO over a skin surface area of 4.78 to 19.12 cm2 also restored locomotor activity to the normal range during a 24-hour period. We suggest the use of transdermal application of PHNO as a novel drug delivery system for the improved management of Parkinson's disease.

The distribution of the orphan bombesin receptor subtype-3 in the rat CNS.

Bombesin receptor subtype 3 (BRS-3) is an orphan G-protein coupled receptor that shares between 47 and 51% homology with other known bombesin receptors. The natural ligand for BRS-3 is currently unknown and little is known about the mechanisms regulating BRS-3 gene expression. Unlike other mammalian bombesin receptors that have been shown to be predominantly expressed in the CNS and gastrointestinal tract, expression of the BRS-3 receptor in the rat brain has previously not been observed. To gain further understanding of the biology of BRS-3, we have studied the distribution of BRS-3 mRNA and protein in the rat CNS. The mRNA expression pattern was studied using reverse transcription followed by quantitative polymerase chain reaction. Using immunohistological techniques, the distribution of BRS-3 protein in the rat brain was investigated using a rabbit affinity-purified polyclonal antiserum raised against an N-terminal peptide. The BRS-3 receptor was found to be widely expressed in the rat brain at both mRNA and protein levels. Particularly strong immunosignals were observed in the cerebral cortex, hippocampal formation, hypothalamus and thalamus. Other regions of the brain such as the basal ganglia, midbrain and reticular formation were also immunopositive for BRS-3. In conclusion, our neuroanatomical data provide evidence that BRS-3 is as widely expressed in the rat brain as other bombesin-like peptide receptors and suggest that this receptor may also have important roles in the CNS, mediating the functions of a so far unidentified ligand.

The three-dimensional localization of internal mammary lymph nodes by radionuclide lymphoscintigraphy.

In breast cancer patients, radiation therapy planning must account for individual anatomy to ensure optimal coverage of tumor and internal mammary nodes. To achieve this, three-dimensional radionuclide lymphoscintigraphy (RNLS) was performed in 167 patients by obtaining two images of the nodes using a 30-degree slant hole collimator rotated 180 degrees between images. Analysis of 768 nodes (mean 4.6/patient) visualized from the level of rib 1 through interspace 5 was performed. The number of nodes seen was not a function of patient age. Cross-communication to the contralateral node chain occurred in 13.8% of cases. Eighty-two percent of nodes were located near the first three ribs and interspaces; 23% were located beyond 3.0 cm from the mid-sternal line. At the level of the radiation beam match line (second rib or interspace), 4.5% of nodes were deeper than 3.0 cm. From rib 3 through interspace 5, 3.9% were deeper than 3.0 cm. Using an idealized tangential field, at least one node would have been missed in 16.2% of patients. Three-dimensional RNLS allows definition and localization of normal sized nodes and ensures that radiation therapy portals can be tailored for each individual under treatment.

Clinical comparison of two radiocolloids for internal mammary lymphoscintigraphy.

Recent studies suggest that 99mTc-labeled radiocolloid (SC) compounded with hydrogen sulfide can be used to visualize lymph channels and nodes. Our study prospectively compared SC with 99mTc antimony sulfide (SbS) colloid, in 28 patients undergoing internal mammary lymphoscintigraphy. Images were recorded on a scintillation camera and computer at 0.5, 1.0, and 3.0 hr. Quantitative analysis included assessment of percent (%) injected dose in nodes, the percent remaining at the injection site, and the relative intensity of the most cephalad node compared to a 57Co standard. The mean (means) % injected dose of both radiocolloids within visualized nodes was less than 1% at each time interval, with no significant differences between means's. The means % injected dose remaining at the injection site at 3.0 hr was 83 for SbS and 76 for SC not statistically significant (N.S.). The means of the ratio of counts within the most cephalad node at 3.0 hr to counts within a 57Co standard was 0.98 for SbS and 1.03 for SC (N.S.). Clinical assessment of number of nodes visualized and extent of radiocolloid migration showed no difference between the two agents. The biological and clinical parameters for the two colloids appear similar when used for internal mammary lymphoscintigraphy.

Neutralisation of heparan sulphate and low molecular weight heparin by protamine.

The neutralisation by protamine sulphate (PS) of heparan sulphate (HS), a low molecular weight heparin (LMWH), and a reference preparation of unfractionated heparin (UH), was studied by activated partial thromboplastin time (APTT) and anti-Xa clotting assays. UH was most easily neutralised in the APTT assay by PS (on a weight for weight basis), followed by LMWH and HS. The neutralisation of APTT activity by PS closely followed the loss of activity in the anti-Xa clotting assay, when plasma was used as the source of At III. When the anti-Xa clotting assay was carried out using purified At III in place of plasma, HS and LMWH were neutralised by much lower amounts of PS and resembled UH neutralisation more closely. Resistance of HS anti-Xa activity to PS neutralisation decreased with increasing plasma dilution. The presence of bovine albumin with purified At III concentrate increased the resistance of HS to PS neutralisation. It is concluded that PS binding to UH, HS and LMWH is probably related more to their degree of sulphation than molecular weight and that non-specific interactions between PS and plasma proteins inhibit the binding of PS to HS and LMWH.

Anticoagulant activities of pentosan polysulphate (Hémoclar) due to release of hepatic triglyceride lipase (HTGL).

Subcutaneous injections of 50 mg pentosan polysulphate (Hémoclar) were given to normal volunteers and the effects on anti-Factor Xa activity, thrombin generation and lipase release measured. Concentrations of pentosan polysulphate were measured by a competitive binding assay and the mean peak level found to be 1.6 micrograms/ml. Anti-Xa clotting activity rose to 0.034 iu/ml and thrombin generation induced by lipid peroxides was inhibited by approximately 50%. Neither of these effects could be accounted for by the direct action of pentosan polysulphate at the concentrations measured. Pentosan polysulphate was very effective in releasing lipase, approximately 70-80% of the total enzyme activity being due to hepatic triglyceride lipase (HTGL). In vitro addition of purified HTGL to plasma markedly enhanced anti-Xa clotting activity, and caused a 70% inhibition of lipid peroxide induced thrombin generation. Anti-Xa activity of post-injection plasma was increased rather than neutralised by addition of polybrene, and this effect could be mimicked by addition of polybrene to plasma containing pentosan polysulphate and purified HTGL. It is concluded that, when given in low doses subcutaneously, pentosan polysulphate acts as an indirect anticoagulant, its major effects being due to release of HTGL.

Keeping hostility in perspective: coronary heart disease and the Hostility Scale on the Minnesota Multiphasic Personality Inventory.

Three prospective studies from the early 1980s found that high scores on the Hostility (Ho) Scale of the Minnesota Multiphasic Personality Inventory (MMPI) were associated with an increased incidence of coronary heart disease (CHD) and mortality from CHD and other causes. In the current study, the association between the Ho score and subsequent health status was examined in a 20-year follow-up of 620 general medical patients who completed the MMPI between 1962 and 1965. Univariately, the Ho score from the MMPI was a significant factor for predicting the development of CHD, CHD-related mortality, and total mortality. When two simple risk factors for CHD--age and sex--were also considered, however, the MMPI Ho score was no longer a significant predictive factor.

Compressive neuropathy of the brachial plexus and long thoracic nerve: a rare complication of heparin anticoagulation.

We present a case of a 69-year-old woman who developed brachial plexopathy and long thoracic nerve palsy secondary to compression from a hematoma while receiving heparin therapy for the treatment of a stroke. The patient was treated conservatively with discontinuation of heparin and had complete resolution of her compressive neuropathy. This is the first report of a patient with long thoracic nerve palsy with a brachial plexopathy complicating anticoagulation. We review the literature on hematoma-induced compressive neuropathies and treatment options. Our review concludes by emphasizing the importance of clinical judgment in determining the best therapeutic modality.