Measurement of the Charge-Averaged Elastic Lepton-Proton Scattering Cross Section by the OLYMPUS Experiment.

We report the first measurement of the average of the electron-proton and positron-proton elastic scattering cross sections. This lepton charge-averaged cross section is insensitive to the leading effects of hard two-photon exchange, giving more robust access to the proton's electromagnetic form factors. The cross section was extracted from data taken by the OLYMPUS experiment at DESY, in which alternating stored electron and positron beams were scattered from a windowless gaseous hydrogen target. Elastic scattering events were identified from the coincident detection of the scattered lepton and recoil proton in a large-acceptance toroidal spectrometer. The luminosity was determined from the rates of Møller, Bhabha, and elastic scattering in forward electromagnetic calorimeters. The data provide some selectivity between existing form factor global fits and will provide valuable constraints to future fits.

Surgical resolution of uterine prolapse in three pet rabbits.

This report describes a surgical technique for resolution of uterine prolapse in rabbits. Three pet rabbits presented within 24 hours of parturition with a red mass protruding from the vagina, which was diagnosed as uterine prolapse. In the first case, an attempt to reduce the prolapse by manual compression was ineffective. A laparotomy was used to apply internal uterine traction while simultaneously using gentle external pressure with cotton-tip applicators and resulted in successful resolution. After repositioning, an ovariohysterovaginectomy was performed in all three rabbits. All rabbits recovered uneventfully. Laparotomic repositioning of the uterus and ovariohysterovaginectomy, not previously described in rabbits, was easy to perform and permitted resolution of uterine prolapse.

Device for inductive heating and focusing of laser produced plasma.

The design and implementation of a pulsed magnetic induction device used to heat and focus a laser produced plasma in vacuum is described. Imaging of the plasma light emission and optical spectroscopy show that the UV/visible light emission is strongly enhanced, and the degree of ionization is increased. The plasma focusing is confirmed by contraction of the deposits formed by the plasma transmitted through the induction coil. The operation of the device can be described in the framework of resistive magnetohydrodynamics, where the induced currents heat the plasma and focus the plasma via the Lorentz interaction with the magnetic field.

Diagnostic utility of fluorodeoxyglucose positron emission tomography in prosthetic joint infection based on MSIS criteria.

AIMS: Prosthetic joint infection (PJI) and aseptic loosening in total hip arthroplasty (THA) can present with pain and osteolysis. The Musculoskeletal Infection Society (MSIS) has provided criteria for the diagnosis of PJI. The aim of our study was to analyze the utility of F18-fluorodeoxyglucose (FDG) positron emission tomography (PET) CT scan in the preoperative diagnosis of septic loosening in THA, based on the current MSIS definition of prosthetic joint infection. PATIENTS AND METHODS: A total of 130 painful unilateral cemented THAs with a mean follow-up of 5.17 years (sd 1.12) were included in this prospective study. The mean patient age was 67.5 years (sd 4.85). Preoperative evaluation with inflammatory markers, aspiration, and an F18 FDG PET scan were performed. Diagnostic utility tests were also performed, based on the MSIS criteria for PJI and three samples positive on culture alone. RESULTS: The mean erythrocyte sedimentation rate, C-reactive protein, and white cell count were 47.83 mm/hr, 25.21 mg/l, and 11.05 × 109/l, respectively. The sensitivity, specificity, accuracy, negative predictive value, and false-positive rate of FDG PET compared with MSIS criteria were 94.87%, 38.46 %, 56.38%, 94.59 %, and 60.21%, respectively. The false-positive rate of FDG PET compared with culture alone was 77.4%. CONCLUSION: FDG PET has a definitive role in the preoperative evaluation of suspected PJI. This the first study to evaluate its utility based on MSIS criteria and compare it with microbiology results alone. However, FDG PET has a high false-positive rate. Therefore, we suggest that F18 FDG PET is useful in confirming the absence of infection, but if positive, may not be confirmatory of PJI. Cite this article: Bone Joint J 2019;101-B:910-914.

Light scattering and random lasing in aqueous suspensions of hexagonal boron nitride nanoflakes.

Liquid phase exfoliation allows large scale production of 2D materials in solution. The particles are highly anisotropic and strongly scatter light. While spherical particles can be accurately and precisely described by a single parameter-the radius, 2D nanoflakes, however, cannot be so easily described. We investigate light scattering in aqueous solutions of 2D hexagonal boron nitride nanoflakes in the single and multiple scattering regimes. In the single scattering regime, the anisotropic 2D materials show a much stronger depolarization of light when compared to spherical particles of similar size. In the multiple scattering regime, the scattering as a function of optical path for hexagonal boron nitride nanoflakes of a given lateral length was found to be qualitatively equivalent to scattering from spheres with the same diameter. We also report the presence of random lasing in high concentration suspensions of aqueous h-BN mixed with Rhodamine B dye. The h-BN works as a scattering agent and Rhodamine B as a gain medium for the process. We observed random lasing at 587 nm with a threshold energy of 0.8 mJ.

Atmospheric pulsed laser deposition and thermal annealing of plasmonic silver nanoparticle films.

A new method for pulsed laser deposition of plasmonic silver nanoparticle (NP) films in flowing gas at atmospheric pressure is described. The ablation was done using an excimer laser at 248 nm. Fast optical imaging shows that the ablation plume is captured by the flowing gas, and is expected to form a NP aerosol, which is carried 5-20 mm to the substrate. The dependence of the deposition rate on laser fluence, gas flow velocity, and target-substrate distance was investigated using electron microscopy and absorption spectroscopy of the deposited films. The NP films were annealed in argon and hydrogen at 400 °C, and in air for temperatures in the range 200 °C-900 °C, leading to strong enhancement, and narrowing of the surface plasmon resonance. The films were used for surface enhanced Raman spectroscopy of a 10-5 molar solution of Rhodamine 6G; films annealed in air at 400 °C were five times more sensitive than the as-deposited films.

Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering Determined by the OLYMPUS Experiment.

The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R_{2γ}, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ≈20° to 80°. The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved gas electron multiplier and multiwire proportional chamber detectors at 12°, as well as symmetric Møller or Bhabha calorimeters at 1.29°. A total integrated luminosity of 4.5 fb^{-1} was collected. In the extraction of R_{2γ}, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of R_{2γ}, presented here for a wide range of virtual photon polarization 0.456<ε<0.978, are smaller than some hadronic two-photon exchange calculations predict, but are in reasonable agreement with a subtracted dispersion model and a phenomenological fit to the form factor data.

An in-vacuo optical levitation trap for high-intensity laser interaction experiments with isolated microtargets.

We report on the design, construction, and characterisation of a new class of in-vacuo optical levitation trap optimised for use in high-intensity, high-energy laser interaction experiments. The system uses a focused, vertically propagating continuous wave laser beam to capture and manipulate micro-targets by photon momentum transfer at much longer working distances than commonly used by optical tweezer systems. A high speed (10 kHz) optical imaging and signal acquisition system was implemented for tracking the levitated droplets position and dynamic behaviour under atmospheric and vacuum conditions, with ±5 µm spatial resolution. Optical trapping of 10 ± 4 µm oil droplets in vacuum was demonstrated, over timescales of >1 h at extended distances of ∼40 mm from the final focusing optic. The stability of the levitated droplet was such that it would stay in alignment with a ∼7 µm irradiating beam focal spot for up to 5 min without the need for re-adjustment. The performance of the trap was assessed in a series of high-intensity (10(17) W cm(-2)) laser experiments that measured the X-ray source size and inferred free-electron temperature of a single isolated droplet target, along with a measurement of the emitted radio-frequency pulse. These initial tests demonstrated the use of optically levitated microdroplets as a robust target platform for further high-intensity laser interaction and point source studies.

Two, four, six, eight... stop and count before it is too late! An audit on swab, needle and instrument counts in theatre.

A concurrent audit was conducted over a four week period to determine if the counting of swabs, needles and instruments for surgery adhered to local policy and recommended guidelines. Data were collected on 30 abdominal surgical procedures. This audit highlighted failings in the count process. It identified poor communication within the multidisciplinary team. There needs to be an increased awareness about local policy, national and international guidelines regarding the counting of swabs, needles and instruments for all surgical procedures.

Assessment of a blood preservation protocol for use in ferrets before transfusion.

Blood transfusion has been described in ferrets as a treatment for oestrus-associated anaemia and as a life-saving therapy following trauma, iatrogenic (usually surgery-induced) anaemia, autoimmune haemolytic anaemia and pure red cell aplasia. Although blood banking is a common method for storage of feline and canine blood it is not currently done with ferret blood. The aim of this study was to determine the shelf-life of ferret blood using the anticoagulant citrate-phosphate-dextrose-solution with adenine (CPDA). Two male ferrets were used as blood donors. From each ferret, 6 ml of blood was taken from the cranial vena cava and stored in 10 ml polyethylene terephthalate (PET) blood tubes containing 1 ml of CPDA solution. Blood was taken from each ferret once per month for five months. These 10 blood samples were stored in a laboratory refrigerator at 4°C for four weeks. Biochemical (glucose, pH, lactate, potassium, sodium) and haematological (haematocrit, light microscopic blood smear examination) analyses were performed on the stored blood at days 0, 7, 14, 21 and 28. Biochemical analyses revealed a progressive decrease from day seven in the stored blood pH, glucose and sodium, with a concomitant increase in lactate and potassium. These results are attributable to the ongoing metabolism and deterioration of the red blood cells (RBC) while in storage, and are more rapid than described for human or canine stored blood. Haematological analyses revealed a progressive elevation of the haematocrit due to the appearance of hypochromic red blood cells and echinocytes beginning at day 7. Haemolysis was observed in the microhaematocrit capillary tube sample by day 21, and microscopic clots were visible on the blood smear by day 28. The low blood pH and the appearance of many hypochromic RBCs and some echinocytes from day 7 in CPDA-stored ferret blood, suggest stored ferret blood has a short shelf-life when compared with stored human or canine blood. We recommend that ferret blood stored in CPDA should not be used for transfusion after seven days of storage at 4°C.

FLOTAC for diagnosis of endo-parasites in pet squirrels in southern Italy.

The present study investigated the occurrence of endoparasites in pet squirrels in southern Italy. Fresh fecal samples were collected from 50 asymptomatic pet squirrels belonging to five different species (Callosciurus finlaysonii, n=6, C. prevosti, n=6; Tamias striatus, n=26, T. sibiricus, n=10; Sciurus carolinensis, n=2) housed both in pet shops and/or in private residences. All fecal samples were processed using the FLOTAC pellet technique to identify and count helminth eggs/larvae and protozoan cysts/oocysts. In addition, to detect Cryptosporidium spp. and Giardia spp. the samples were analyzed by the Remel Xpect(®) immunoassay. Helminth eggs were detected in 9 out of 50 squirrels. Specifically, eggs of Dicrocoelium dendriticum were found in 5 squirrels (C. finlaysonii, n=2; C. prevosti, n=2; T. striatus, n=1); eggs of the pinworm Syphacia spp. in 3 squirrels (C. prevosti, n=2; T. striatus, n=1); and eggs of gastrointestinal nematoda (Nippostrongylus-like) were found in 1 subject (C. prevosti). Finally, two squirrels (C. prevosti) had multiple parasitic infections with D. dendriticum and Capillaria hepatica, and with D. dendriticum and Strongyloides spp., respectively. None of the samples were positive for Cryptosporidium spp. or Giardia spp. or any other protozoa (e.g. Eimeria). To the authors' knowledge, this is the first report of a D. dendriticum natural infection in pet rodents.

How does gender influence immigrant and refugee women's postpartum depression help-seeking experiences?

The number of migrants arriving in Canada from non-European countries has grown significantly over the past three decades. How best to assist these escalating numbers of immigrant and refugee women to adapt to their new environment and to cope with postpartum depression (PPD) is a pressing issue for healthcare providers. Evidence has shown that immigrant and refugee women experience difficulties in accessing care and treatment for PPD. This qualitative study was conducted with 30 immigrant and refugee women using in-depth interviews to obtain information about the women's PPD experiences. The primary aim was to explore how cultural, social, political, historical and economic factors intersect with race, gender and class to influence the ways in which immigrant and refugee women seek help to manage PPD. Results reveal that immigrant and refugee women experience many complex gender-related challenges and facilitators in seeking equitable help for PPD treatment and prevention. We will demonstrate that (a) structural barriers and gender roles hinder women's ability to access necessary mental healthcare services and (b) insecure immigration status coupled with emotional and economic dependence may leave women vulnerable and disadvantaged in protecting themselves against PPD.

Meson-exchange currents and quasielastic antineutrino cross sections in the superscaling approximation.

We evaluate quasielastic double-differential antineutrino cross sections obtained in a phenomenological model based on the superscaling behavior of electron scattering data and estimate the contribution of the vector meson-exchange currents in the two-particle-two-hole sector. We show that the impact of meson-exchange currents for charge-changing antineutrino reactions is much larger than in the neutrino case.

CO2 laser pulse shortening by laser ablation of a metal target.

A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO(2) laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to ~2 ns and to remove the low power, long duration tails that are present in TEA CO(2) pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is ~10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.

Evidence of the harmonic Faraday instability in ultrasonic atomization experiments with a deep, inviscid fluid.

A popular method for generating micron-sized aerosols is to submerge ultrasonic (ω~MHz) piezoelectric oscillators in a water bath. The submerged oscillator atomizes the fluid, creating droplets with radii proportional to the wavelength of the standing wave at the fluid surface. Classical theory for the Faraday instability predicts a parametric instability driving a capillary wave at the subharmonic (ω/2) frequency. For many applications it is desirable to reduce the size of the droplets; however, using higher frequency oscillators becomes impractical beyond a few MHz. Observations are presented that demonstrate that smaller droplets may also be created by increasing the driving amplitude of the oscillator, and that this effect becomes more pronounced for large driving frequencies. It is shown that these observations are consistent with a transition from droplets associated with subharmonic (ω/2) capillary waves to harmonic (ω) capillary waves induced by larger driving frequencies and amplitudes, as predicted by a stability analysis of the capillary waves.

Immigrant and refugee women's post-partum depression help-seeking experiences and access to care: a review and analysis of the literature.

ACCESSIBLE SUMMARY: • This literature review on post-partum depression (PPD) presents an analysis of the literature about PPD and the positive and negative factors, which may influence immigrant and refugee women's health seeking behaviour and decision making about post-partum care. • A critical review of English language peer-reviewed publications from 1988 to 2008 was done by the researchers as part of a qualitative research study conducted in a western province of Canada. The overall goal of the study is to raise awareness and understanding of what would be helpful in meeting the mental health needs of the immigrant and refugee women during the post-partum period. • Several online databases were searched: Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, MEDLINE (Ovid), EBM Reviews - Cochrane Database of Systematic Reviews. • Review of the literature suggests: 1 Needs, issues and specific risk factors for PPD among immigrant and refugee women have been limited. 2 Descriptive accounts regarding culture and PPD are found in the literature but impact of cultural factors upon PPD has not been well studied. 3 Few studies look at how social support, gender, and larger institutions or organizational structures may affect immigrant and refugee women's help-seeking and access to mental health care services. 4 More research is needed to hear the immigrant and refugee women's ideas about their social support needs, the difficulties they experience and their preferred ways of getting help with PPD. ABSTRACT: This review and analysis of the literature is about the phenomenon of post-partum depression (PPD) and the barriers and facilitators, which may influence immigrant and refugee women's health seeking behaviour and decision making about post-partum care. As part of a qualitative research study conducted in a western province of Canada a critical review of English language peer-reviewed publications from 1988 to 2008 was undertaken by the researchers. The overall goal of the study is to raise awareness and understanding of what would be helpful in meeting the mental health needs of the immigrant and refugee women during the post-partum period. Several online databases were searched: Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, MEDLINE (Ovid), EBM Reviews - Cochrane Database of Systematic Reviews. Findings suggest: (1) needs, issues and specific risk factors for PPD among immigrant and refugee women have been limited; (2) descriptive accounts regarding culture and PPD are found in the literature but impact of cultural factors upon PPD has not been well investigated; (3) few studies examine how social support, gender, institutional and organizational structures present barriers to the women's health seeking behaviour; and (4) additional research is required to evaluate immigrant and refugee women's perspectives about their social support needs, the barriers they experience and their preferred support interventions.

Generation of nanoparticles of controlled size using ultrasonic piezoelectric oscillators in solution.

We demonstrate the operation of a device that can produce chitosan nanoparticles in a tunable size range from 50-300 nm with small size dispersion. A piezoelectric oscillator operated at megahertz frequencies is used to aerosolize a solution containing dissolved chitosan. The solvent is then evaporated from the aerosolized droplets in a heat pipe, leaving monodisperse nanoparticles to be collected. The nanoparticle size is controlled both by the concentration of the dissolved polymer and by the size of the aerosol droplets that are created. Our device can be used with any polymer or polymer/therapeutic combination that can be prepared in a homogeneous solution and vaporized.

Generation of Mie size microdroplet aerosols with applications in laser-driven fusion experiments.

We have developed a tunable source of Mie scale microdroplet aerosols that can be used for the generation of energetic ions. To demonstrate this potential, a terawatt Ti:Al2O3 laser focused to 2 x 10(19) W/cm2 was used to irradiate heavy water (D2O) aerosols composed of micron-scale droplets. Energetic deuterium ions, which were generated in the laser-droplet interaction, produced deuterium-deuterium fusion with approximately 2 x 10(3) fusion neutrons measured per joule of incident laser energy.