79 research outputs found

    Refractive femtosecond laser beam shaping for two-photon polymerization

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    Three dimensional microstructure fabrication by two-photon polymerization is an established technique that normally uses single beam serial writing. Recently the use of a micro-optical element, to give multipoint beam delivery, was reported to give a degree of parallel processing. The authors describe an alternative approach to parallel processing using an axicon lens. This is a refractive element that, in combination with a high power microscope objective, efficiently transforms the laser beam from a Gaussian spot to an annulus. The authors demonstrate that the beam can polymerize a three dimensional shape, with nanoscale resolution. The use of more sophisticated refractive beam shaping is also discussed. (c) 2007 American Institute of Physics. (DOI:10.1063/1.2713787

    The application of inelastic neutron scattering to investigate the interaction of methyl propanoate with silica

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    A modern industrial route for the manufacture of methyl methacrylate involves the reaction of methyl propanoate and formaldehyde over a silica-supported Cs catalyst. Although the process has been successfully commercialised, little is known about the surface interactions responsible for the forward chemistry. This work concentrates upon the interaction of methyl propanoate over a representative silica. A combination of infrared spectroscopy, inelastic neutron scattering, DFT calculations, X-ray diffraction and temperature-programmed desorption is used to deduce how the ester interacts with the silica surface

    The cultural importance and international recognition of the Arctic charr Salvelinus alpinus populations of Windermere, UK

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    The Arctic charr Salvelinus alpinus populations of Windermere, England’s largest natural lake in the Lake District of north-west England, have been studied since the 1940s. However, the species’ cultural importance has a much longer history and these populations have been fished since 1223. As early as 1660, Arctic charr were exploited in a high-profile commercial net fishery and greatly enjoyed by locals and in a ‘potted’ form by wealthier members of UK society. However, overfishing led to substantially decreased catches and commercial netting was stopped in 1921. Local fishing for Arctic charr persists to the present as a small recreational plumb-line fishery using artificial lures. These fishing activities and resulting catches have long held great cultural interest for the local community and visiting national and international tourists. The cultural importance of the Arctic charr populations of Windermere has recently been the subject of national media interest that culminated in a 2017 documentary film highlighting environmental issues facing the Arctic charr and also celebrating the role of this iconic species in the cultural life of Windermere. In addition, international recognition of the Arctic charr populations of Windermere also contributed to the Lake District becoming a UNESCO World Heritage Site in 2017

    A decade of living lobar lung transplantation: recipient outcomes

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    AbstractObjectiveLiving lobar lung transplantation was developed as a procedure for patients considered too ill to await cadaveric transplantation.MethodsOne hundred twenty-eight living lobar lung transplantations were performed in 123 patients between 1993 and 2003. Eighty-four patients were adults (age, 27 ± 7.7 years), and 39 were pediatric patients (age, 13.9 ± 2.9 years).ResultsThe primary indication for transplantation was cystic fibrosis (84%). At the time of transplantation, 67.5% of patients were hospitalized, and 17.9% were intubated. One-, 3-, and 5-year actuarial survival among living lobar recipients was 70%, 54%, and 45%, respectively. There was no difference in actuarial survival between adult and pediatric living lobar recipients (P = .65). There were 63 deaths among living lobar recipients, with infection being the predominant cause (53.4%), followed by obliterative bronchiolitis (12.7%) and primary graft dysfunction (7.9%). The overall incidence of acute rejection was 0.8 episodes per patient. Seventy-eight percent of rejection episodes were unilateral. Age, sex, indication, donor relationship, preoperative hospitalization status, use of preoperative steroids, and HLA-A, HLA-B, and HLA-DR typing did not influence survival. However, patients on ventilators preoperatively had significantly worse outcomes (odds ratio, 3.06, P = .03; Kaplan-Meier P = .002), and those undergoing retransplantation had an increased risk of death (odds ratio, 2.50).ConclusionThese results support the continued use of living lobar lung transplantation in patients deemed unable to await a cadaveric transplantation. We consider patients undergoing retransplantations and intubated patients to be at significantly high risk because of the poor outcomes in these populations

    Progress report no. 1

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    Statement of responsibility on title-page reads: Editors: I.A. Forbes, M.J. Driscoll, D.D. Lanning, I. Kaplan, N.C. Rasmussen; Contributors: S.A. Ali, S.T. Brewer, D.K. Choi, F.M. Clikeman, W.R. Corcoran, M.J. Driscoll, I.A. Forbes, C.W. Forsberg, S.L. Ho, C.S. Kang, I. Kaplan, J.L. Klucar, D.D. Lanning, T.C. Leung, E.L. McFarland P.G. Mertens, N.R. Ortiz, A. Pant, N.A. Passman, N.C. Rasmussen, M.K. Sheaffer, D.A. Shupe, G.E. Sullivan, A.T. Supple, J.W. Synan, C.P. Tzanos, W.J. Westlake"MIT-4105-3."Includes bibliographical referencesProgress report; June 30, 1970U.S. Atomic Energy Commission contracts: AT(30-1)410

    Harnessing landrace diversity empowers wheat breeding

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    Harnessing genetic diversity in major staple crops through the development of new breeding capabilities is essential to ensure food security1. Here we examined the genetic and phenotypic diversity of the A.E. Watkins landrace collection2 of bread wheat (Triticum aestivum), a major global cereal, through whole-genome re-sequencing (827 Watkins landraces and 208 modern cultivars) and in-depth field evaluation spanning a decade. We discovered that modern cultivars are derived from just two of the seven ancestral groups of wheat and maintain very long-range haplotype integrity. The remaining five groups represent untapped genetic sources, providing access to landrace-specific alleles and haplotypes for breeding. Linkage disequilibrium (LD) based haplotypes and association genetics analyses link Watkins genomes to the thousands of high-resolution quantitative trait loci (QTL), and significant marker-trait associations identified. Using these structured germplasm, genotyping and informatics resources, we revealed many Watkins-unique beneficial haplotypes that can confer superior traits in modern wheat. Furthermore, we assessed the phenotypic effects of 44,338 Watkins-unique haplotypes, introgressed from 143 prioritised QTL in the context of modern cultivars, bridging the gap between landrace diversity and current breeding. This study establishes a framework for systematically utilising genetic diversity in crop improvement to achieve sustainable food security.</p

    Design mining microbial fuel cell cascades

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    Microbial fuel cells (MFCs) perform wastewater treatment and electricity production through the conversion of organic matter using microorganisms. For practical applications, it has been suggested that greater efficiency can be achieved by arranging multiple MFC units into physical stacks in a cascade with feedstock flowing sequentially between units. In this article, we investigate the use of cooperative coevolution to physically explore and optimise (potentially) heterogeneous MFC designs in a cascade, i.e., without simulation. Conductive structures are 3D printed and inserted into the anodic chamber of each MFC unit, augmenting a carbon fibre veil anode and affecting the hydrodynamics, including the feedstock volume and hydraulic retention time, as well as providing unique habitats for microbial colonisation. We show that it is possible to use design mining to identify new conductive inserts that increase both the cascade power output and power density
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