Laboratory realization of relativistic pair-plasma beams.

Relativistic electron-positron plasmas are ubiquitous in extreme astrophysical environments such as black-hole and neutron-star magnetospheres, where accretion-powered jets and pulsar winds are expected to be enriched with electron-positron pairs. Their role in the dynamics of such environments is in many cases believed to be fundamental, but their behavior differs significantly from typical electron-ion plasmas due to the matter-antimatter symmetry of the charged components. So far, our experimental inability to produce large yields of positrons in quasi-neutral beams has restricted the understanding of electron-positron pair plasmas to simple numerical and analytical studies, which are rather limited. We present the first experimental results confirming the generation of high-density, quasi-neutral, relativistic electron-positron pair beams using the 440 GeV/c beam at CERN's Super Proton Synchrotron (SPS) accelerator. Monte Carlo simulations agree well with the experimental data and show that the characteristic scales necessary for collective plasma behavior, such as the Debye length and the collisionless skin depth, are exceeded by the measured size of the produced pair beams. Our work opens up the possibility of directly probing the microphysics of pair plasmas beyond quasi-linear evolution into regimes that are challenging to simulate or measure via astronomical observations.

Three-vessel view debridement of the open tibial fracture: a surgical technique.

Adequate debridement of an open fracture is a key component of successful management. Despite having set debridement principles, there is no structured technique available in the literature to guide the surgeon in achieving this. We therefore present a technical note detailing the structured approach to the debridement of any open tibial fracture. Our unit has developed a novel stepwise technique termed locally as the "three-vessel view". Identifying all three primary vessels of the leg facilitates confirmation of inspection of all lower limb compartments thus minimising the risk of missed devitalised tissue or neglected areas of contamination and the potential for consequent disastrous outcomes as a result of inadequate exposure.

Inefficient Magnetic-Field Amplification in Supersonic Laser-Plasma Turbulence.

We report a laser-plasma experiment that was carried out at the LMJ-PETAL facility and realized the first magnetized, turbulent, supersonic (Ma_{turb}≈2.5) plasma with a large magnetic Reynolds number (Rm≈45) in the laboratory. Initial seed magnetic fields were amplified, but only moderately so, and did not become dynamically significant. A notable absence of magnetic energy at scales smaller than the outer scale of the turbulent cascade was also observed. Our results support the notion that moderately supersonic, low-magnetic-Prandtl-number plasma turbulence is inefficient at amplifying magnetic fields compared to its subsonic, incompressible counterpart.

Observations of pressure anisotropy effects within semi-collisional magnetized plasma bubbles.

Magnetized plasma interactions are ubiquitous in astrophysical and laboratory plasmas. Various physical effects have been shown to be important within colliding plasma flows influenced by opposing magnetic fields, however, experimental verification of the mechanisms within the interaction region has remained elusive. Here we discuss a laser-plasma experiment whereby experimental results verify that Biermann battery generated magnetic fields are advected by Nernst flows and anisotropic pressure effects dominate these flows in a reconnection region. These fields are mapped using time-resolved proton probing in multiple directions. Various experimental, modelling and analytical techniques demonstrate the importance of anisotropic pressure in semi-collisional, high-ß plasmas, causing a reduction in the magnitude of the reconnecting fields when compared to resistive processes. Anisotropic pressure dynamics are crucial in collisionless plasmas, but are often neglected in collisional plasmas. We show pressure anisotropy to be essential in maintaining the interaction layer, redistributing magnetic fields even for semi-collisional, high energy density physics (HEDP) regimes.

Effective rescue treatment with vemurafenib of an infant with high-risk Langerhans cell histiocytosis.

INTRODUCTION: The recently identified role of a BRAF somatic mutation in the pathophysiology of Langerhans cell histiocytosis (LCH) offers new therapeutic options. Herein we describe the case of a 10-month-old infant with refractory high-risk LCH successfully treated with vemurafenib. OBSERVATION: The patient first presented with cutaneous LCH at the age of 2 months. The disease remained undiagnosed until she was 6 months old, when it rapidly evolved to a multisystemic high-risk and life-threatening disease, refractory to 2 lines of chemotherapy. BRAFV600E mutation was found at skin biopsy, and targeted therapy with vemurafenib was started when she was 10 months old. The treatment induced a fast and sustained response, but rapid relapse occurred after treatment discontinuation, leading to resumption of treatment, once more resulting in a sustained response. CONCLUSION: Our case highlights the first-line role of dermatologists in establishing the diagnosis of LCH, especially in children, in whom the eruption may be difficult to identify, leading to delayed diagnosis. Targeted therapy with vemurafenib has recently been described in children in this indication and our results support its efficacy, highlighting the need for prolonged treatment and raising the question of maintenance therapy, as well as the necessity for large-scale and long-term studies.

Role of collisionality and radiative cooling in supersonic plasma jet collisions of different materials.

Currently there is considerable interest in creating scalable laboratory plasmas to study the mechanisms behind the formation and evolution of astrophysical phenomena such as Herbig-Haro objects and supernova remnants. Laboratory-scaled experiments can provide a well diagnosed and repeatable supplement to direct observations of these extraterrestrial objects if they meet similarity criteria demonstrating that the same physics govern both systems. Here, we present a study on the role of collision and cooling rates on shock formation using colliding jets from opposed conical wire arrays on a compact pulsed-power driver. These diverse conditions were achieved by changing the wire material feeding the jets, since the ion-ion mean free path (λ_{mfp-ii}) and radiative cooling rates (P_{rad}) increase with atomic number. Low Z carbon flows produced smooth, temporally stable shocks. Weakly collisional, moderately cooled aluminum flows produced strong shocks that developed signs of thermal condensation instabilities and turbulence. Weakly collisional, strongly cooled copper flows collided to form thin shocks that developed inconsistently and fragmented. Effectively collisionless, strongly cooled tungsten flows interpenetrated, producing long axial density perturbations.

Retrieving fields from proton radiography without source profiles.

Proton radiography is a technique in high-energy density science to diagnose magnetic and/or electric fields in a plasma by firing a proton beam and detecting its modulated intensity profile on a screen. Current approaches to retrieve the integrated field from the modulated intensity profile require the unmodulated beam intensity profile before the interaction, which is rarely available experimentally due to shot-to-shot variability. In this paper, we present a statistical method to retrieve the integrated field without needing to know the exact source profile. We apply our method to experimental data, showing the robustness of our approach. Our proposed technique allows for the retrieval not only of the path-integrated fields, but also of the statistical properties of the fields.

Thomson scattering cross section in a magnetized, high-density plasma.

We calculate the Thomson scattering cross section in a nonrelativistic, magnetized, high-density plasma-in a regime where collective excitations can be described by magnetohydrodynamics. We show that, in addition to cyclotron resonances and an elastic peak, the cross section exhibits two pairs of peaks associated with slow and fast magnetosonic waves; by contrast, the cross section arising in pure hydrodynamics possesses just a single pair of Brillouin peaks. Both the position and the width of these magnetosonic-wave peaks depend on the ambient magnetic field and temperature, as well as transport and thermodynamic coefficients, and so can therefore serve as a diagnostic tool for plasma properties that are otherwise challenging to measure.

Supersonic plasma turbulence in the laboratory.

The properties of supersonic, compressible plasma turbulence determine the behavior of many terrestrial and astrophysical systems. In the interstellar medium and molecular clouds, compressible turbulence plays a vital role in star formation and the evolution of our galaxy. Observations of the density and velocity power spectra in the Orion B and Perseus molecular clouds show large deviations from those predicted for incompressible turbulence. Hydrodynamic simulations attribute this to the high Mach number in the interstellar medium (ISM), although the exact details of this dependence are not well understood. Here we investigate experimentally the statistical behavior of boundary-free supersonic turbulence created by the collision of two laser-driven high-velocity turbulent plasma jets. The Mach number dependence of the slopes of the density and velocity power spectra agree with astrophysical observations, and supports the notion that the turbulence transitions from being Kolmogorov-like at low Mach number to being more Burgers-like at higher Mach numbers.

Quantifying the effects of a low-ozone event and shallow stratocumulus clouds on ultraviolet erythemal radiation exposure.

Meteorological and dosimetric ultraviolet (UV) erythemal radiation (UVER) measurements were performed in Didcot, England, on 6 and 7 April 2017. Both days were characterized by clear-sky conditions in the morning and the afternoon with development of shallow stratocumulus clouds (SSC) around noon. In addition, a low-ozone event occurred on 7 April characterized by a 34 DU (Dobson Unit) drop in total stratospheric ozone content. Compared to 6 April, the ozone mini-hole caused UVER increases of 2.67 standard erythema dose (SED) for diffuse and 4.32 SED for global radiation characterized by radiation amplification factors (RAF) of 1.62 and 1.52, respectively. The total global UVER dose reductions due to SSC coverage amount to 2.33 SED (6 April) and 2.81 SED (7 April). As innovation the RAF is decomposed into two parts, named cloud ozone factor (COF) and radiation amplification factor based on measured data (RAFm), to quantify the low-ozone event's effect and the SSC influence in independently modifying the UVER doses. Hereby, the weight of each of these two effects acting during the same low-ozone event is expressed by the new COF. In this case, the COF values range between -0.13 and -0.11 for diffuse UVER and -0.03 to -0.07 for the global UV and UV-B parts. A positive COF value (0.18) results for the global UV-A range.

Laboratory evidence of dynamo amplification of magnetic fields in a turbulent plasma.

Magnetic fields are ubiquitous in the Universe. The energy density of these fields is typically comparable to the energy density of the fluid motions of the plasma in which they are embedded, making magnetic fields essential players in the dynamics of the luminous matter. The standard theoretical model for the origin of these strong magnetic fields is through the amplification of tiny seed fields via turbulent dynamo to the level consistent with current observations. However, experimental demonstration of the turbulent dynamo mechanism has remained elusive, since it requires plasma conditions that are extremely hard to re-create in terrestrial laboratories. Here we demonstrate, using laser-produced colliding plasma flows, that turbulence is indeed capable of rapidly amplifying seed fields to near equipartition with the turbulent fluid motions. These results support the notion that turbulent dynamo is a viable mechanism responsible for the observed present-day magnetization.

MicroRNA-206 functions as a pleiotropic modulator of cell proliferation, invasion and lymphangiogenesis in pancreatic adenocarcinoma by targeting ANXA2 and KRAS genes.

Recent advances in cancer biology have emerged important roles for microRNAs (miRNAs) in regulating tumor responses. However, their function in mediating intercellular communication within the tumor microenvironment is thus far poorly explored. Here, we found miR-206 to be abrogated in human pancreatic ductal adenocarcinoma (PDAC) specimens and cell lines. We show that miR-206 directly targets the oncogenes KRAS and annexin a2 (ANXA2), thereby acting as tumor suppressor in PDAC cells by blocking cell cycle progression, cell proliferation, migration and invasion. Importantly, we identified miR-206 as a negative regulator of oncogenic KRAS-induced nuclear factor-κB transcriptional activity, resulting in a concomitant reduction of the expression and secretion of pro-angiogenic and pro-inflammatory factors including the cytokine interleukin-8, the chemokines (C-X-C motif) ligand 1 and (C-C motif) ligand 2, and the granulocyte macrophage colony-stimulating factor. We further show that miR-206 abrogates the expression and secretion of the potent pro-lymphangiogenic factor vascular endothelial growth factor C in pancreatic cancer cells through an NF-κB-independent mechanism. By using in vitro and in vivo approaches, we reveal that re-expression of miR-206 in PDAC cells is sufficient to inhibit tumor blood and lymphatic vessel formation, thus leading to a significant delay of tumor growth and progression. Taken together, our study sheds light onto the role of miR-206 as a pleiotropic modulator of different hallmarks of cancer, and as such raising the intriguing possibility that miR-206 may be an attractive candidate for miRNA-based anticancer therapies.

Improving emergency department management of paediatric clavicle fractures: a complete audit cycle.

A protocol was devised to address the issue of unnecessary attendance at fracture clinic by children who have a fracture of the clavicle that is deemed to be uncomplicated. For the purposes of this protocol, the clavicle was divided into three zones. Fractures of the middle clavicle for which displacement was minimal, heal quickly in the majority of cases, without the need for follow up. As a result these children can be discharged provided the parents are adequately advised. This article outlines a study which investigated the effectiveness of the protocol. The study found that implementation of the protocol reduced unnecessary attendance at clinic from 85% (47/55) to 17% (4/23). This resulted in cost savings to the trust and reduced the pressure on staff working in busy fracture clinics.

Preparation and electrochemical behavior of gramicidin-bipolar lipid monolayer membranes supported on gold electrodes.

Gramicidin-containing synthetic bolalipid membranes comprised of 2,2'-di-O-decyl-3,3'-O-1,20-eicosanyl-bis-rac-glycero-1,1'-diphosphocholine (C20BAS) have been synthesized and supported on gold electrodes. Supported membranes were prepared by first depositing a partial bolalipid layer on the electrode using a thioctic acid-modified bolalipid (1'-O-omega-thioctamidetetraethylene glycol-2,2'-di-O-decyl-3,3'-di-O-1,20-eicosanyl-bis-rac-glycero-1-phosphate, SSC20BAS) as an anchoring group, followed by a vesicle fusion step using either pure C20BAS or gramicidin-containing C20BAS (C20BAS-GA) vesicles. The latter configuration was designed to immobilize single, continuously-on channels of gramicidin in the C20BAS membrane. Vesicle deposition to form supported bolalipid monolayer membranes was monitored by impedance spectroscopy and cyclic voltammetry. Impedances were observed to increase with vesicle deposition time. Pretreatment of the impedance electrode with SSC20BAS accelerated the supported monolayer membrane deposition rate. Impedances decreased in a gramicidin concentration-dependent manner when gramicidin was incorporated into the C20BAS membrane. These supported bolalipid membranes are also surprisingly inert to organic solvent exposure (CH(3)CH(2)OH;CH(2)Cl(2)), suggesting that they may serve as robust host matrices for integral membrane protein-based sensors.

Routine analysis of 101 polychlorinated biphenyl congeners in human serum by parallel dual-column gas chromatography with electron capture detection.

Polychlorinated biphenyl (PCB) exposure has been linked to a variety of toxic effects in animal experiments and in certain human case reports and epidemiologic studies. A total of 209 individual PCB congeners are possible, based on chlorination level and ring substitution pattern. Commercial PCBs are a complex mixture of congeners, and over 75 of these have been reported to be present in human tissues at widely varying levels. Because the biologic activity of individual PCBs is a function of extent and pattern of chlorine substitution, "congener-specific" PCB analysis of human tissue has gained increasing importance in assessing possible links between PCB exposure and toxic effects. A high-sensitivity analytical method using dual-column gas chromatography (GC) with electron capture detection (ECD) for determining 101 PCB congeners (83 individual, 18 as pairs/triplets) plus 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), hexachlorobenzene (HCB), and mirex, in human serum is described. Separation is performed concurrently on parallel-configured DB-5 and Apiezon-L capillary columns. The current method is a modification of previously reported dual-column GC-ECD systems with improvements to the extraction and analytical protocols and the implementation of a comprehensive QA/QC program. The method employs two surrogate standards (PCBs IUPAC 125 and 192) and internal standard (IUPAC 104)-based quantitation, in addition to per-batch check standards and method blanks. Although optimized for serum, the method is applicable to all human, experimental animal, and environmental biota samples. The accuracy, precision, and reliability of the method were assessed using a variety of QA/QC endpoints. Finally, the use of the method in determining level and prevalence of PCB congeners in a cohort of adult Native-American individuals with historical environmental PCB exposure is reported.

[Atropine poisoning. Importance of the clinical diagnosis]. / Intossicazione da atropina. Importanza della diagnosi clinica.

A case of suspected high dose atropine poisoning is described. In a veterinarian good healthy young man the appearance of light coma with psychomotor agitation and the contemporary presence of evident symptoms of muscarinic peripheral block, suggesting an anticholinergic syndrome, an atropine-like intoxication in absence of toxicological analysis. The safely clinical course of the poisoning during observation in intensive care unit permitted the discharge of the patient without sequelae and without treatment with physostigmine as antidote.

Preparation and biodistribution of copper-67 complexes with tetradentate Schiff-base ligands.

Uncharged, lipophilic, low molecular weight copper complexes labeled with generator-produced copper-62 are of interest as potential radiopharmaceutials for imaging the brain with positron emission tomography (PET). We report here the synthesis and biodistribution of a series of [67Cu]copper(II) complexes with tetradentate N2O2(2-)Schiff-base ligands. The compounds studied varied in lipophilicity from log P = 1.7 to log P = 3.6, where P is the octanol/water partition coefficient. In rat biodistribution studies the tracers were generally found to penetrate the blood-brain barrier following intravenous injection, but some far better than others. For closely related compounds brain uptake at 1 min postinjection increased with increasing lipophilicity, although log P was clearly not the sole determinant of high brain uptake. Substantial variations were also observed in the rate at which these various compounds are cleared from brain, with a few exhibiting the prolonged cerebral retention of tracer that would be desired for imaging with 62Cu and PET.

[The nutritive effect of Bacillus cereus as a probiotic in the raising of piglets. 2. Effect and microbial count, composition and resistance determination of gastrointestinal and fecal microflora]. / Zur nutritiven Wirksamkeit von Bacillus cereus als Probiotikum in der Ferkelaufzucht. 2. Mitteilung--Einfluss auf Keimzahlen, Zusammensetzung und Resistenzeigenschaften der gastrointestinalen und faecalen Mikroflora.

After a feeding trial of 42 days with 4 x 12 piglets 4 x 6 piglets were slaughtered and the influence of spores of the Bacillus cereus strain FH 1457 S added to the feed on the microorganism counts of Lactobacillus/Bifidobacterium, Eubacteria, Bacteroidaceae, E. coli, Enterococcus and passants (Bacillus cereus) in duodenum, jejunum, ileum, caecum and colon was investigated. Beside a negative control the feed was supplemented with 10(7), 10(8) and 10(9) CFU Bacillus cereus/kg. The feeding trial included two periods each of 21 days. In each period faeces was collected from all animals and the influence on the microorganism counts and also the frequency of resistance of the E. coli and Enterococcus germs against selected antibiotics and chemotherapeutics investigated. The addition of 10(8) CFU Bacillus cereus decreased E. coli counts in duodenum and jejunum, however increased them in ileum, caecum and colon. In the highest dosage the counts of Bacillus cereus in duodenum, caecum, colon and faeces were significantly higher. The addition of Bacillus cereus reduced the counts of E. coli and Enterococcus in faeces in the first period. In the second period the dosage 10(8) CFU showed significant increased counts of E. coli and the sums of microorganisms of the main and satellite flora. The additions had no influence on the frequency of resistance of E. coli and enterococci against the tested antibiotics and synthetic chemotherapeutics. From the addition of Bacillus cereus in this case a selection of factors influencing resistance is not to be expected.