332 research outputs found

    From white elephant to Nobel Prize: Dennis Gabor’s wavefront reconstruction

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    Dennis Gabor devised a new concept for optical imaging in 1947 that went by a variety of names over the following decade: holoscopy, wavefront reconstruction, interference microscopy, diffraction microscopy and Gaboroscopy. A well-connected and creative research engineer, Gabor worked actively to publicize and exploit his concept, but the scheme failed to capture the interest of many researchers. Gabor’s theory was repeatedly deemed unintuitive and baffling; the technique was appraised by his contemporaries to be of dubious practicality and, at best, constrained to a narrow branch of science. By the late 1950s, Gabor’s subject had been assessed by its handful of practitioners to be a white elephant. Nevertheless, the concept was later rehabilitated by the research of Emmett Leith and Juris Upatnieks at the University of Michigan, and Yury Denisyuk at the Vavilov Institute in Leningrad. What had been judged a failure was recast as a success: evaluations of Gabor’s work were transformed during the 1960s, when it was represented as the foundation on which to construct the new and distinctly different subject of holography, a re-evaluation that gained the Nobel Prize for Physics for Gabor alone in 1971. This paper focuses on the difficulties experienced in constructing a meaningful subject, a practical application and a viable technical community from Gabor’s ideas during the decade 1947-1957

    Tomato: a crop species amenable to improvement by cellular and molecular methods

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    Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures. In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.

    Application of coded apertures in tomographic head scanning

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    A circular ring tomograph, designated SPRINT, is under development for single photon emission tomography of the human head. Most data to date have been gathered using a single rotating slit inside the detector ring to define ray directions. As an alternative method, we have also investigated the use of multiplexed slit patterns consisting of a pseudorandom binary code. From theoretical considerations, one would expect that the substitution of the code for the single slit would have potential advantages in reducing statistical noise in tomographic images of small objects. It has been our experience that this improvement is marginal at best for the types of source distributions encountered in clinical brain imaging. However, the code shows substantial advantage in suppressing uncorrelated backgrounds and the effects of highly penetrating gamma ray components in the source.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24867/1/0000294.pd

    Updated protocol and guest participant results from the ACCeRT clinical study

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    Introduction Cancer cachexia is a condition often seen at diagnosis, throughout chemotherapeutic treatments and in end stage Non-Small Cell Lung Cancer patients. These patients often experience a shorter life-expectancy and deterioration in performance status and reduced quality of life. New multi˗targeted regimens are required to be tested in this population to address these issues. Materials and methods The ACCeRT study is an open label, prospective, randomised controlled feasibility study investigating the use of eicosapentaenoic acid and COX-2 inhibitor (celecoxib) versus eicosapentaenoic acid, COX-2 inhibitor (celecoxib), progressive resistance training followed by ingestion of essential amino acids high in leucine in Non-Small Cell Lung Cancer cachectic patients. The study protocol was published in November 2011. Due to study participants and study team preferences a number of changes were made. Firstly, a change from a bolus drink containing 20 g of essential amino acids to an encapsulated form in divided doses over three days. Secondly, a change in leg strength analysis from utilising a leg/back dynamometry to a customised chair with a load cell testing extension isometric force. Thirdly, study drug dose reductions were now permitted. Fourthly, addition of two study sites which allowed participants to attend progressive resistance training sessions in their local area. Finally, a change in inclusion criteria to include participants that had received any first-line anti-cancer treatment. A guest participant was invited onto the study in April 2012, followed by the first study participant in June 2012. Results The guest participant showed trends in efficacy in a number of outcomes; stable fat free mass in the context of decreasing total body weight, with stable FAACT˗PWB, MFSI-SF physical, and WHOQOL-BREF QOL scores at week 20, all during documented disease progression now termed refractory cachexia. There were no treatment or exercise-related adverse events. Conclusion Publishing feasibility study protocols allows transparency in study interventions and assessments. The above ACCeRT regimen stabilised fat free mass and a number of physical/performance indicators and QOL in the guest participant

    Preserving Madagascar’s Natural Heritage: The Importance of Keeping the Islands’s Fossils in the Public Domain

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    Article argues for the development of adequate repositories and support infrastructure in Madagascar to safeguard and display the country’s vertebrate fossil collections; doing so would ensure the preservation and appreciation of Madagascar’s rich natural heritage for future generations of scientists and Malagasy citizens alike

    Updated protocol and guest participant results from the ACCeRT clinical study

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    Introduction Cancer cachexia is a condition often seen at diagnosis, throughout chemotherapeutic treatments and in end stage Non-Small Cell Lung Cancer patients. These patients often experience a shorter life-expectancy and deterioration in performance status and reduced quality of life. New multi˗targeted regimens are required to be tested in this population to address these issues. Materials and methods The ACCeRT study is an open label, prospective, randomised controlled feasibility study investigating the use of eicosapentaenoic acid and COX-2 inhibitor (celecoxib) versus eicosapentaenoic acid, COX-2 inhibitor (celecoxib), progressive resistance training followed by ingestion of essential amino acids high in leucine in Non-Small Cell Lung Cancer cachectic patients. The study protocol was published in November 2011. Due to study participants and study team preferences a number of changes were made. Firstly, a change from a bolus drink containing 20 g of essential amino acids to an encapsulated form in divided doses over three days. Secondly, a change in leg strength analysis from utilising a leg/back dynamometry to a customised chair with a load cell testing extension isometric force. Thirdly, study drug dose reductions were now permitted. Fourthly, addition of two study sites which allowed participants to attend progressive resistance training sessions in their local area. Finally, a change in inclusion criteria to include participants that had received any first-line anti-cancer treatment. A guest participant was invited onto the study in April 2012, followed by the first study participant in June 2012. Results The guest participant showed trends in efficacy in a number of outcomes; stable fat free mass in the context of decreasing total body weight, with stable FAACT˗PWB, MFSI-SF physical, and WHOQOL-BREF QOL scores at week 20, all during documented disease progression now termed refractory cachexia. There were no treatment or exercise-related adverse events. Conclusion Publishing feasibility study protocols allows transparency in study interventions and assessments. The above ACCeRT regimen stabilised fat free mass and a number of physical/performance indicators and QOL in the guest participant

    A multi-targeted treatment approch to cancer cachexia: Auckland's Cancer Cachexia evaluating Resistance Training (ACCeRT) trial

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    Abstract Background Cancer cachexia is a condition often seen at diagnosis, throughout anti-cancer treatments and in end-stage nonsmall- cell lung cancer patients. Methods and results Participants with late-stage non-small-cell lung cancer and cachexia (defined as ≥5% weight loss within 12 months) were randomly assigned 1:2 to 2.09 g of eicosapentaenoic acid (EPA) and 300 mg of cyclo-oxygenase-2 inhibitor celecoxib orally once daily vs. same dosing of EPA, celecoxib, plus two sessions per week of progressive resistance training and 20 g of oral essential amino acids high in leucine in a split dose over 3 days, after each session. Primary endpoint was the acceptability of the earlier multi-targeted approach. Main secondary endpoints included change in body weight and fat-free mass, by bioelectric impedance analysis and total quadriceps muscle volume by magnetic resonance imaging over 20 weeks. Sixty-nine patients were screened resulting in 20 patients being enrolled. Acceptability scored high, with 4.5/5 (Arm A) and 5/5 (Arm B) for EPA and 5/5 for celecoxib within both arms and 4.8/5 for progressive resistance training sessions and 4.5/5 for essential amino acids within Arm B, all at Week 20. Results showed a net gain in bioelectric impedance analysis fat-free mass of +1.3 kg, n = 2 (Arm A), compared with +0.7 kg, n = 7 (Arm B) at Week 12, and —1.5 kg, n = 2 (Arm A), compared with —1.7 kg, n = 4 (Arm B) at Week 20. Trends in efficacy in terms of improvement and/or stability in cachexia markers were seen within magnetic resonance imaging muscle volume, albumin, and C-reactive protein levels within both arms. There were no exercise-related adverse events, with one possible related adverse event of asymptomatic atrial fibrillation in one participant within Arm A. Conclusions Non-small-cell lung cancer cachectic patients are willing to be enrolled onto a multi-targeted treatment regimen and may benefit from cachexia symptom management even during the late/refractory stage

    Hydration status affects thirst and salt preference but not energy intake or postprandial ghrelin in healthy adults : a randomised crossover trial

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    Background Few studies have investigated the effect of hydration status on appetite for food in healthy adults. Prior work suggests hydration status does not alter appetite or energy intake, with mixed findings regarding appetite hormone secretion. However, an extensive investigation into both the psychological and physiological appetitive responses to hydration status has never been conducted. Objective To investigate the effect of hydration status on multiple facets of appetite. Design After 3 days pre-trial standardization, a range of appetite tasks were conducted when hypohydrated (HYPO) and euhydrated (EUHY) in 16 healthy participants (8 men). Hydration status was manipulated via dehydration in a heat tent for 60 min and subsequent fluid restriction (HYPO) or replacement (EUHY). The next day, a food reward computer task was completed followed by an ad libitum pasta meal. Pre- and post-prandial visual analogue scales assessing hunger, fullness, and flavour desires (sweet, salty, savoury and fatty) were additionally completed. Blood samples were taken the previous day before the hydration interventions in a euhydrated state, and in the fasted and post-prandial state during HYPO and EUHY. Results HYPO induced -1.9 ± 1.2% body mass change, compared to -0.2 ± 0.6% , with accompanying changes in markers of hypohydration which were not seen during EUHY. A higher desire for foods was associated with a higher water content but the association was weaker in EUHY compared to HYPO, (β= -0.33 mm/g of food water content, p < 0.001) in the food reward task. Visual analogue scales showed similar hunger and fullness between interventions, but during HYPO there was consistently higher thirst (average range in difference 27–32 mm across all time points) and lower fasted desire for salt (−23, 95% CI −10, −35 mm). Ad libitum energy intake (HYPO 1953 ± 742 kJ, EUHY 2027 ± 926 kJ; p = 0.542) and post-prandial ghrelin concentrations (HYPO 180 ± 65 pg mL−1, EUHY 188 ± 71 pg mL−1; p = 0.736) were similar by hydration status. Conclusions An acute manipulation to hydration status altered desire for salt and foods of differing water contents, but did not influence energy intake at an ad libitum pasta meal. Further research should investigate whether these appetites would alter food choice
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