1,165 research outputs found

    Characterization of single-crystal synthetic diamond for multi-watt continuous-wave Raman lasers

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    A continuous-wave diamond Raman laser is demonstrated with an output power of 5.1 W at 1217 nm. This Raman laser is intracavity pumped by a side-pumped Nd:YLF rod laser: a 43-fold brightness enhancement between the Nd:YLF and diamond Raman lasers is observed, with the M2 beam propagation factor of the diamond Raman laser measured to be <; 1.2. Although higher output powers are demonstrated in a similar configuration using KGd(WO4)2 (KGW) as the Raman laser material (6.1 W), the brightness enhancement is much lower (2.5 fold) due to the poorer beam quality of the KGW Raman laser (M2 <; 6). The Raman gain coefficient of single-crystal synthetic diamond at a pump wavelength of 1064-nm is also measured: a maximum value of 21±2 cm/GW is returned compared to 5.7±0.5 cm/GW for KGW at the same wavelength

    Social marketing-based strategy for sun protection interventions

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    The promotion of sensible sun protection behaviours is constrained by:-The perception that skin cancer risk in the UK is low. The population is not sensitized to skin cancer as a major health risk in the same way as are Australasian populations -The lack of central government support for and endorsement or funding of interventions-Strong normative beliefs, particularly among young people about the social value of suntans and prevailing social norms regarding the attractiveness of suntans and acceptable behaviours modelled among peers -A lack of integration of messages and behaviours among stakeholder groups (e.g. schools, where there is evidence that policies are inconsistent and, in some schools, children may actually be discouraged from bringing sunscreen to schools).Additionally, recent media coverage hyping the benefits of Vitamin D as both a preventative and curative element (including cancers) will also impact on the way future interventions are received.Insights that led to the recommendations that follow are:-‘trigger’ moments are very important – sun protection is not something that is of major concern / top of mind in the UK winter, so linking activities to moments when sun protection is high on people’s agendas is important.- there are two main tasks to be done: first, gaining a general awareness that too much sun is harmful, but understanding this on its own is unlikely to shift behaviour. Second, creating specific propositions that people will accept – these offerings leading to lower risk behaviours in an acceptable way.In the short term, we recommend immediate implementation of:-activities that can leverage off the existing SunSmart UK brand -direct beach and other outdoor lifestyle face-to face-interventions-highly targeted communications at parents, teachers, young adults and outdoor workers to continue the long term task of building sustained awareness of skin cancer risks and appropriate behaviours. Ideally, this would be best achieved nationally through high profile mass media such as television, however funding for this appears unlikely. In the longer term, priority in developing and implementing interventions should be given to:-obtaining government assistance in raising awareness of the link between unwise sun exposure and skin cancer in the UK, and in the South West region in particular-ensuring integration of messages and actions among stakeholder groups and consistency with national, regional and local initiatives.-gaining media buy-in and support in promoting sensible sun protection behaviour, clarifying the link between sun exposure and vitamin D (and claims made for the latter)-addressing overall gaps in the population’s knowledge and awareness of safe sun exposure practices-focusing specifically tailored interventions on clearly identified segments, drawing on theoretical foundations and knowledge of the very different attitudes and beliefs held by each segment to develop appropriate messages-raising awareness of the need for early detection and treatment, supported by appropriate infrastructure to facilitate screening and referrals to specialist services where appropriate-utilising collaborative activity with appropriate organisations such as pharmacies, food retailers and sporting organisations to link with, and leverage off, their activity in this area and to ensur communication themes are consistent with ‘best practice’-setting benchmark measures ththe development of an on-going tracking prre intervention effectiveness and to enable intervee-tuned as necessaryimary research within each segment to deep insights and to enable programmes to be monitored over time

    Southern Ocean laminated diatom ooze: mat deposits and potential for palaeo-flux studies, ODP leg 177, Site 1093

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    International audienceLaminated diatom ooze samples collected during ODP Leg 177 were analysed using scanning electron microscope (SEM) and optical microscopy to test their potential as high-resolution records of Polar Front hydrography, surface production, and export. SEM analysis from two intervals, marine isotope stage (MIS) 29 and 12/11, respectively, recovered from 50°S in the Atlantic Ocean (ODP Site 1093, Hole A, sections 13H-4 0–18 cm and 23H-4 0–22 cm), show abundant and well-preserved Thalassiothrix antarctica mats, thought to be indicative of rapid export from the surface and deposition in the sediment. A preliminary analysis of laminae succession points to a possible annual couplet/triplet succession of laminae, and suggests exceptionally high local sedimentation rates of 57 and 80 cm kyr−1 for MIS 12/11 and 29, respectively. Such high accumulation rates imply that local export from the surface layer and sequestration of biogenic silica and organic matter to the sediments may have been much higher than previously suggested

    Fetal skin as a pro-inflammatory organ: Evidence from a primate model of chorioamnionitis.

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    BackgroundIntrauterine infection is a primary cause of preterm birth and fetal injury. The pro-inflammatory role of the fetal skin in the setting of intrauterine infection remains poorly characterized. Whether or not inflammation of the fetal skin occurs in primates remains unstudied. Accordingly, we hypothesized that: i) the fetal primate skin would mount a pro-inflammatory response to preterm birth associated pro-inflammatory agents (lipopolysaccharides from Escherichia coli, live Ureaplasma parvum, interleukin-1β) and; ii) that inhibiting interleukin-1 signaling would decrease the skin inflammatory response.MethodsRhesus macaques with singleton pregnancies received intraamniotic injections of either sterile saline (control) or one of three pro-inflammatory agonists: E. coli lipopolysaccharides, interluekin-1β or live U. parvum under ultrasound guidance. A fourth group of animals received both E. coli lipopolysaccharide and interleukin-1 signaling inhibitor interleukin-1 receptor antagonist (Anakinra) prior to delivery. Animals were surgically delivered at approximately 130 days' gestational age.ResultsIntraamniotic lipopolysaccharide caused an inflammatory skin response characterized by increases in interluekin-1β,-6 and -8 mRNA at 16 hours. There was a modest inflammatory response to U. parvum, but interleukin-1β alone caused no inflammatory response in the fetal skin. Intraamniotic Anakinra treatment of lipopolysaccharide-exposed animals significantly reduced skin inflammation.ConclusionsIntraamniotic lipopolysaccharide and U. parvum were associated with modest increases in the expression of inflammatory mediators in primate fetal skin. Although administration of Interleukin-1β alone did not elicit an inflammatory response, lipopolysaccharide-driven skin inflammation was decreased following intraamniotic Anakinra therapy. These findings provide support for the role of the fetal skin in the development of the fetal inflammatory response

    Organic-Conventional Dairy Systems Trial in New Zealand: Four Years’ Results

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    The Organic-Conventional Comparative Dairy Systems trial at Massey University began in August 2001, and the organic farmlet achieved certification in August 2003. The trial is unique because it is the only comparative grassland-based open grazing dairy study in the world. The organic and conventional systems are managed individually according to best practice, and both are intensively monitored for production, animal health, and environmental impacts. The systems remained similar for the first two years, but began to diverge in the third and fourth years. Production has been 10-20% lower on the organic farm, but environmental impacts appear to be less than on the conventional unit, and net incomes would be similar given a 20% price premium for the organic product. Animal health issues have been manageable on the organic farmlet, and not too dissimilar from the conventional farmlet. Full results after four years of the trial will be available and presented at the conference

    Sustained inflation at birth did not alter lung injury from mechanical ventilation in surfactant-treated fetal lambs.

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    BackgroundSustained inflations (SI) are used with the initiation of ventilation at birth to rapidly recruit functional residual capacity and may decrease lung injury and the need for mechanical ventilation in preterm infants. However, a 20 second SI in surfactant-deficient preterm lambs caused an acute phase injury response without decreasing lung injury from subsequent mechanical ventilation.HypothesisA 20 second SI at birth will decrease lung injury from mechanical ventilation in surfactant-treated preterm fetal lambs.MethodsThe head and chest of fetal sheep at 126±1 day GA were exteriorized, with tracheostomy and removal of fetal lung fluid prior to treatment with surfactant (300 mg in 15 ml saline). Fetal lambs were randomized to one of four 15 minute interventions: 1) PEEP 8 cmH2O; 2) 20 sec SI at 40 cmH2O, then PEEP 8 cmH2O; 3) mechanical ventilation with 7 ml/kg tidal volume; or 4) 20 sec SI then mechanical ventilation at 7 ml/kg. Fetal lambs remained on placental support for the intervention and for 30 min after the intervention.ResultsSI recruited a mean volume of 6.8±0.8 mL/kg. SI did not alter respiratory physiology during mechanical ventilation. Heat shock protein (HSP) 70, HSP60, and total protein in lung fluid similarly increased in both ventilation groups. Modest pro-inflammatory cytokine and acute phase responses, with or without SI, were similar with ventilation. SI alone did not increase markers of injury.ConclusionIn surfactant treated fetal lambs, a 20 sec SI did not alter ventilation physiology or markers of lung injury from mechanical ventilation

    Continuous-wave Raman laser pumped within a semiconductor disk laser cavity

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    A KGd(WO4)(2) Raman laser was pumped within the cavity of a cw diode-pumped InGaAs semiconductor disk laser (SDL). The Raman laser threshold was reached for 5: 6W of absorbed diode pump power, and output power up to 0.8W at 1143nm, with optical conversion efficiency of 7.5% with respect to the absorbed diode pump power, was demonstrated. Tuning the SDL resulted in tuning of the Raman laser output between 1133 and 1157nm

    Steady-state Raman gain in diamond as a function of pump wavelength

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    The variation in the Raman gain coefficient in single-crystal diamond for pump wavelengths between 355 and 1450 nm is measured. Two techniques are used: a pump-probe approach giving an absolute measurement and a stimulated Raman oscillation threshold technique giving a relative measurement. Both approaches indicate that the Raman gain coefficient is a linear function of pump wavenumber. With the pump polarized along a direction in the crystal, the Raman gain coefficient measured by the pump-probe technique is found to vary from 7.6 +/- 0.8 for a pump wavelength of 1280 nm to 78 +/- 8 cm/GW for a pump wavelength of 355 nm. With the established dependence of the Raman gain coefficient on the pump wavelength, the Raman gain coefficient can be estimated at any pump wavelength within the spectral range from 355 up to 1450 nm
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