604 research outputs found

    Equine digital tendons show breed‐specific differences in their mechanical properties that may relate to athletic ability and predisposition to injury

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    Background Throughout the ages, human subjects have selected horse breeds for their locomotor capacities. Concurrently, tissue properties may have diversified because of specific requirements of different disciplines. Objectives The aim of this study was to compare the biomechanical properties of tendons with different functions between equine breeds traditionally selected for racing or sport. Study design This study used ex vivo tendons and compared the mechanical properties of the common digital extensor tendon (CDET) and superficial digital flexor tendon (SDFT) between racehorses (Thoroughbred [TB]) and sports horses (Friesian Horse [FH], Warmblood [WB]). Methods The SDFT and CDET of FH (n = 12), WBs (n = 12) and TBs (n = 8) aged 3-12 years were harvested. The cross sectional area (cm(2)), maximal load (N), ultimate strain (%), ultimate stress (MPa) and elastic modulus (MPa) were determined and tested for significant differences between the breeds (P<0.05). Results The SDFT from WB horses had a significantly lower elastic modulus than TB horses and failed at a higher strain and load than both FHs and TBs. The mechanical properties of the CDET did not differ between breeds. In agreement with previous studies, the CDET failed at a higher stress and had a higher elastic modulus than the SDFT and, for the WB group of horses only, failed at a significantly lower strain. Interestingly, the mode of failure differed between breeds, particularly with respect to the FHs. Main limitations The exercise history of horses used in this study was unknown and the age-range was relatively large; both these factors may have influenced the absolute properties reported in this study. Conclusions This study shows for the first time that mechanical properties of the SDFT differ between breeds. These properties are likely to be related to selection for high-speed vs. an extravagant elastic gait and may be an important indicator of performance ability. The is available in Spanish - see Supporting Informatio

    The Use of Silver Phenyl Benzyl Phosphate for the Synthesis of Monophenyl Esters of Phosphatidic Acids

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    Hessel, Morton, Todd, and Verkade have shown that dibenzyl esters of a-glycerophosphatidic acids I (D = acyl group), when shaken at room temperature in an ethanolic medium with hydrogen under slightly more than atmospheric pressure in the presence of a palladium/ active carbon catalyst according to Verkade, Cohen, and Vroege are smoothly hydrogenolyzed; 2 moles of hydrogen per mole of ester are rapidly absorbed, resulting in the formation of the corresponding phosphatidic acids and toluene

    The Use of Silver Phenyl Benzyl Phosphate for the Synthesis of Monophenyl Esters of Phosphatidic Acids

    Get PDF
    Hessel, Morton, Todd, and Verkade have shown that dibenzyl esters of a-glycerophosphatidic acids I (D = acyl group), when shaken at room temperature in an ethanolic medium with hydrogen under slightly more than atmospheric pressure in the presence of a palladium/ active carbon catalyst according to Verkade, Cohen, and Vroege are smoothly hydrogenolyzed; 2 moles of hydrogen per mole of ester are rapidly absorbed, resulting in the formation of the corresponding phosphatidic acids and toluene

    Defining the natural history of rare genetic liver diseases:Lessons learned from the NAPPED initiative

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    While rare diseases collectively affect similar to 300 million people worldwide, the prevalence of each disease concerns a relatively small number of patients. Usually, only limited data with regard to natural history are available. Multicenter initiatives are needed to aggregate data and answer clinically relevant research questions. In 2017, we launched the NAtural course and Prognosis of PFIC and Effect of biliary Diversion (NAPPED) consortium. In three years, NAPPED created a global network focused on rare genetic liver diseases in the Progressive Familial Intrahepatic Cholestasis (PFIC) spectrum. During these years, we have learned important lessons which we feel should be taken into account when initiating and leading a global consortium.First, it is essential to 'keep it simple' from the start. Research questions, case report forms (CRFs) and data acquisition should be limited and clear to stay focused and keep the workload low for new participants. Secondly, early rewards and research output are needed to keep momentum and motivation. Quick output can only follow a clean and simple design. Thirdly, the leading team should be in touch and accessible. Ideally, an involved PhD-candidate is appointed as primary contact person. Lastly, be inclusive and actively involve all participants the consortium's course.Global consortia are critical for personalized medicine in rare diseases. Also, they are essential for setting up trials to investigate generic drugs and personalized therapies. We hope to herewith stimulate others that are starting (or are planning to start) a global consortium, ultimately to help improve the care for patients with a rare disease.</p

    Using size-selected gold clusters on graphene oxide films to aid cryo-transmission electron tomography alignment

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    A three-dimensional reconstruction of a nano-scale aqueous object can be achieved by taking a series of transmission electron micrographs tilted at different angles in vitreous ice: cryo-Transmission Electron Tomography. Presented here is a novel method of fine alignment for the tilt series. Size-selected gold clusters of ~2.7 nm (Au(561 ± 14)), ~3.2 nm (Au(923 ± 22)), and ~4.3 nm (Au(2057 ± 45)) in diameter were deposited onto separate graphene oxide films overlaying holes on amorphous carbon grids. After plunge freezing and subsequent transfer to cryo-Transmission Electron Tomography, the resulting tomograms have excellent (de-)focus and alignment properties during automatic acquisition. Fine alignment is accurate when the evenly distributed 3.2 nm gold particles are used as fiducial markers, demonstrated with a reconstruction of a tobacco mosaic virus. Using a graphene oxide film means the fiducial markers are not interfering with the ice bound sample and that automated collection is consistent. The use of pre-deposited size-selected clusters means there is no aggregation and a user defined concentration. The size-selected clusters are mono-dispersed and can be produced in a wide size range including 2–5 nm in diameter. The use of size-selected clusters on a graphene oxide films represents a significant technical advance for 3D cryo-electron microscopy

    MECCANISMI DI ACCRESCIMENTO E IDENTIFICAZIONE DI DIFETTI MULTIPLI INDOTTI DA IDROGENO (HYDROGEN STEP WISE CRACKING)

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    Negli acciai, lo sviluppo e la propagazione di cricche interne, dovute alla diffusione di idrogeno, puĂČ aver luogo secondo meccanismi diversi. Negi ambienti contenenti H2S in fase acquosa, conosciuti come H2S umido, Ăš frequente lo sviluppo di difetti multipli interconnessi noti come step wise cracks. E' stato osservato che la distribuzione dei bordi grano della matrice metallica ha una notevole influenza sul modo di propagazione di tali difetti. La caratteristica forma ad S delle cricche sembra essere correlata allo scorrimento e alla rottura dei grani cristallini che si trovano nella regione sottoposta a sforzo di taglio tra le cricche che si interconnettono, cosĂŹ come alla propagazione delle cricche stesse attraverso bordi grano ad alto angolo. L'innesco e la propagazione dell'HIC sono influenzati da molteplici fattori di tipo sia ambientale che metallurgico, tali da poter fare propagare i difetti con velocitĂ  estremamente elevate (in alcuni casi sono stati registrati valori di velocitĂ  di propagazione longitudinale superiori a 15 mm/mese). Nella presente memoria viene evidenziato come l'utilizzo di appropriate tecniche ultrasonore basate sull'analisi del tempo di volo (ToFD) e l'utilizzo di sonde a 45° permette di individuare con buona approssimazione tale tipo di difetti e di poterne seguire l'evoluzione nel tempo

    Long-Term Neurodevelopmental Outcomes in Children with Biliary Atresia

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    Objective: To assess long-term neurodevelopmental outcomes in school-aged children with biliary atresia. Study design: All Dutch children (6-12 years of age) diagnosed with biliary atresia were invited to participate in this study. We used validated neurodevelopmental tests to assess motor skills and cognition, and questionnaires to assess behavior. Scores were compared with the Dutch norm population, by means of 1-sample tests. Results are given as number and percentage or mean ± SD. Results: We included 46 children, with a median age of 11 years (range, 6-13 years); 36 children had undergone a liver transplantation (78%). Twelve children (26%) received special education (vs 2.4% in the norm population; P <.01). Motor outcomes were significantly affected compared with the norm population (P <.01), with 25% normal (vs 85%), 25% borderline (vs 10%), and 50% low scores (vs 5%). Total IQ was lower in patients with biliary atresia, compared with the norm population (91 ± 18 vs 100 ± 15; P <.01). There were no significant differences in test scores between children with native liver and after liver transplantation. Conclusions: School-aged children with biliary atresia show neurodevelopmental impairments compared with the norm population, especially in motor skills. Our data strongly warrant evaluation of neurodevelopmental intervention programs to assess whether long-term outcomes could be improved

    Patients suffering from psychological impairments following critical illness are in need of information

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    Background: Because critical illness survivors frequently experience several long-term psychological impairments altering quality of life after ICU, there is a trend towards increasing follow-up care, mainly via ICU follow-up clinics. Despite these and other initiatives, understanding of patient's post-ICU needs to help them cope with their problems and subsequently improve quality of life is largely lacking. Our aim was therefore to assess the needs, expectations and wishes in ICU survivors to receive information with the purpose to help them better grasp ICU treatment. In addition, we assessed the perceived burden of psychological trauma after ICU treatment and the health-related quality of life (HRQoL) up to 2.5 years after ICU discharge. Methods: In a multicentre, retrospective cross-sectional cohort study, the needs and preferred intervention methods were assessed using a self-composed inventory in adult mechanically ventilated ICU survivors (n = 43). Additionally, the Impact of Event Scale Revised, the Beck Depression Inventory, the EuroQol-5D-5L, and the Short-Form 12 were used to assess psychological burden and HRQoL. Results: A substantial proportion of all ICU survivors (59%, 95% CI 44% to 74%) suffered from psychological impairments after ICU treatment. Seventy-five percent of these patients expressed a wish to receive information, but only 36% desired to receive this information using a commonly used information brochure. In contrast, 71% of these patients had a wish to receive information using a video film/VR. Furthermore, only 33% of these patients was satisfied with the information provided by their treating hospital. Patients with psychological PICS reported a worse HRQoL as compared to a normative Dutch sample (P < 0.001) and as compared to patients without psychological PICS (P < 0.01). Conclusions: In a Dutch cohort of critical illness survivors, a substantial part of ICU survivors suffer from psychological impairments, such as PTSD and depression, which was associated with a worse HRQoL. These patients are in need of information, have no desire using an information brochure, but are willing to receive information using a video film/virtual reality module. These results support the exploration of such an intervention
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