Progress in Developing High Energy Nozzle Beams

Electron beam studies of skimmer phenomena and effect on high energy nozzle beam formatio

Nanosecond laser texturing of aluminium for control of wettability

There is increasing interest in the use of lasers to modify the wettability of surfaces. Here we report on the use of a 20W nS pulsed IR fibre laser to create strong ydrophobicity on the surface of aluminium sheets. This is unexpected, hydrophobicity is usually associated solely with femto- or pico- second laser processing. At a 20W average power level the area coverage rate is too small for many industrial applications. Further trials using a 800W DPSS laser are described and the ability of this system to change surface wettability at a much higher production rate are indicated. There is little reported literature on surface texturing at higher average power levels. Indications of the productivity, or surface coverage rate, are given. Keywords: Fibre lasers, DPSS lasers, Surface Engineering, texturing, wettability, aluminiu

Laser Induced Micro Plasma Processing of Polymer Substrates for Biomedical Implant Applications

This paper reports the experimental results of a new hybrid laser processing technique; Laser Induced Micro Plasma Processing (LIMP2). A transparent substrate is placed on top of a medium that will interact with the laser beam and create a plasma. The plasma and laser beam act in unison to ablate material and create micro-structuring on the “backside” of the substrate. We report the results of a series of experiments on a new laser processing technique that will use the same laser-plasma interaction to micromachining structures into glass and polymer substrates on the “topside” of the substrate and hence machine non-transparent material. This new laser processing technique is called Laser Induced Micro Plasma Processing (LIMP2). Micromachining of biomedical implants is proving an important enabling technology in controlling cell growth on a macro-scale. This paper discusses LIMP2 structuring of transparent substrate such as glasses and polymers for this application. Direct machining of these materials by lasers in the near infrared is at present impossible. Laser Induced Micro Plasma Processing (LIMP2) is a technique that allows laser operating at 1064 nm to machine microstructures directly these transparent substrates. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

30 Yan-nhanu language documentation and revitalisation

Background: Prompt treatment following Transient Ischemic Attack (TIA) can reduce the risk of subsequent stroke and disability. However, many patients delay in making contact with medical services. This study aimed to explore TIA patients’ accounts of delay between symptom onset and contacting medical services including how decisions to contact services were made and the factors discussed in relation to delay. Methods: Twenty interviews were conducted with TIA patients in England. Using a previous systematic review as an initial framework, interview data were organised into categories of symptom recognition, presence of others and type of care sought. A thematic analysis was then conducted to explore descriptions of care-seeking relevant to each category. Results: Delay in contacting medical services varied from less than an hour to eight days. Awareness of typical stroke symptoms could lead to urgent action when more severe TIA symptoms were present but could lead to delay when experienced symptoms were less severe. The role of friends and family varied widely from deciding on and enacting care-seeking decisions to simply providing transport to the GP practice. When family or friends played a greater role, and both made and enacted care-seeking decisions, delays were often shorter, even when patients themselves failed to identify symptoms. Healthcare professionals also impacted on patients ’ care-seeking with greater delays in seeking further care for the same episode described when patients perceived a lack of urgency during initial healthcare interactions

Comparison of tranexamic acid (Transamin) and traditional therapy for sudden deafness.

The effectiveness of tranexamic acid treatment for sudden deafness was studied in detail. The results of treatment with tranexamic acid administration in 19 cases (25 ears) of sudden deafness and two historical control groups using various treatments were compared by the chi square contingency test. The data suggested that tranexamic acid treatment may be superior to traditional treatments especially if treatment is begun early. Among ears treated with tranexamic acid, 11 ears (44%) were healed or recovered remarkably, 8 ears (32%) recovered slightly and 6 ears (24%) were unchanged or worsened. Fibrinolysis in the inner ear may be the pathophysiology of sudden deafness. Treatment with tranexamic acid starting within 4 days after onset of symptoms was most effective in patients whose initial audiogram was flat or concave, initial average hearing loss at 5 frequencies (250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz) was between 23 dB and 76 dB (mean; 45.1 dB) and was not accompanied by dizziness.</p

Intertranslatability, Theoretical Equivalence, and Perversion

I investigate syntactic notions of theoretical equivalence between logical theories and an recent objection thereto. I show that this recent criticism of syntactic accounts as extensionally inadequate is unwarranted by developing an account which is plausibly extensionally adequate and more philosophically motivated. This is important for recent anti-exceptionalist treatments of logic since syntactic accounts require less theoretical baggage than semantic accounts

Carbon nanoparticles fabricated by infrared laser ablation of graphite and polycrystalline diamond targets

This paper presents the results of carbon nanoparticles (CNPs) production by infrared laser ablation of a graphite or a polycrystalline diamond target, submerged in one of two solvents, water or isopropanol. The targets were irradiated using a SPI fibre laser with a wavelength of 1064nm being operated at different average powers. After laser-assisted synthesis of CNPs, the resulting colloids, i.e particles in a liquid medium, were examined using the analytical techniques of dynamic light scattering, UV-Vis, Raman spectroscopy and fluorescence spectroscopy. The results show that the properties of CNPs strongly depend on processing conditions of the liquid phase-pulsed laser ablation (LP-PLA) process. In particular, the size of nanoparticles produced are affected by the processing parameters of the laser ablation. The results show that the laser processing of a graphite target in deionised water and in isopropanol produces carbon nanoparticles with properties that are beneficial for various biochemical and biomedical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Characterising B cell numbers and memory B cells in HIV infected and uninfected Malawian adults

BACKGROUND: Untreated human immunodeficiency virus (HIV) disease disrupts B cell populations causing reduced memory and reduced naïve resting B cells leading to increases in specific co-infections and impaired responses to vaccines. To what extent antiretroviral treatment reverses these changes in an African population is uncertain. METHODS: A cross-sectional study was performed. We recruited HIV-uninfected and HIV-infected Malawian adults both on and off antiretroviral therapy attending the Queen Elizabeth Central hospital in Malawi. Using flow cytometry, we enumerated B cells and characterized memory B cells and compared these measurements by the different recruitment groups. RESULTS: Overall 64 participants were recruited - 20 HIV uninfected (HIV-), 30 HIV infected ART naïve (HIV+N) and 14 HIV-infected ART treated (HIV+T). ART treatment had been taken for a median of 33 months (Range 12-60 months). Compared to HIV- the HIV+N adults had low absolute number of naïve resting B cells (111 vs. 180 cells/μl p = 0.008); reduced memory B cells (27 vs. 51 cells/μl p = 0.0008). The HIV+T adults had B-cell numbers similar to HIV- except for memory B cells that remained significantly lower (30 vs. 51 cells/μl p = 0.02). In the HIV+N group we did not find an association between CD4 count and B cell numbers. CONCLUSIONS: HIV infected Malawian adults have abnormal B-cell numbers. Individuals treated with ART show a return to normal in B-cell numbers but a persistent deficit in the memory subset is noted. This has important implications for long term susceptibility to co-infections and should be evaluated further in a larger cohort study

DNA adducts in fish following an oil spill exposure

On 12 December 1999, one third of the load of the Erika tanker, amounting to about 10,000 t crude oil flowed into sea waters close to the French Atlantic Coast. This oil contained polycyclic aromatic compounds (PAC) that are known to be genotoxic. Genotoxic effects induce DNA adducts formation, which can thus be used as pollution biomarkers. Here, we assessed the genotoxic impact of the “Erika” oil spill by DNA adducts detection in the liver of immature fishes (Solea solea) from four locations of the French Brittany coasts. Two months after the spill, a high amount of DNA adducts was found in samples from all locations, amounting to 92–290 DNA adduct per 109 nucleotides. Then total DNA adduct levels decreased to reach about 50 adducts per 109 nucleotides nine months after the spill. In vitro experiments using human cell cultures and fish liver microsomes evidence the genotoxicity of the Erika fuel. They also prove the formation of reactive species able to create DNA adducts. Furthermore, in vitro and in vivo DNA adducts fingerprints are similar, thus confirming that DNA adducts are a result of the oil spill