247 research outputs found

    Preparation of Sterically Demanding 2,2-Disubstituted-2-Hydroxy Acids by Enzymatic Hydrolysis

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    Preparation of optically-pure derivatives of 2-hydroxy-2-(3-hydroxyphenyl)-2-phenylacetic acid of general structure 2 was accomplished by enzymatic hydrolysis of the correspondent esters. A screening with commercial hydrolases using the methyl ester of 2-hydroxy-2-(3-hydroxyphenyl)-2-phenylacetic acid (1a) showed that crude pig liver esterase (PLE) was the only preparation with catalytic activity. Low enantioselectivity was observed with substrates 1a\u2013d, whereas PLE-catalysed hydrolysis of 1e proceeded with good enantioselectivity (E = 28), after optimization. Enhancement of the enantioselectivity was obtained by chemical re-esterification of enantiomerically enriched 2e, followed by sequential enzymatic hydrolysis with PLE. The preparation of optically-pure (S)-2e was validated on multi-milligram scale

    Comparison of HTK-Custodiol and St-Thomas solution as cardiac preservation solutions on early and midterm outcomes following heart transplantation.

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    The choice of the cardiac preservation solution for myocardial protection at time of heart procurement remains controversial and uncertainties persist regarding its effect on the early and midterm heart transplantation (HTx) outcomes. We retrospectively compared our adult HTx performed with 2 different solutions, in terms of hospital mortality, mid-term survival, inotropic score, primary graft dysfunction and rejection score. From January 2009 to December 2020, 154 consecutive HTx of adult patients, followed up in pre- and post-transplantation by 2 different tertiary centres, were performed at the University Hospital of Lausanne, Switzerland. From 2009 to 2015, the cardiac preservation solution used was exclusively St-Thomas, whereafter an institutional decision was made to use HTK-Custodiol only. Patients were classified in 2 groups accordingly. There were 75 patients in the St-Thomas group and 79 patients in the HTK-Custodiol group. The 2 groups were comparable in terms of preoperative and intraoperative characteristics. Postoperatively, compared to the St-Thomas group, the Custodiol group patients showed significantly lower inotropic scores [median (interquartile range): 35.7 (17.5-60.2) vs 71.8 (31.8-127), P < 0.001], rejection scores [0.08 (0.0-0.25) vs 0.14 (0.05-0.5), P = 0.036] and 30-day mortality rate (2.5% vs 14.7%, P = 0.007) even after adjusting for potential confounders. Microscopic analysis of the endomyocardial biopsies also showed less specific histological features of subendothelial ischaemia (3.8% vs 17.3%, P = 0.006). There was no difference in primary graft dysfunction requiring postoperative extracorporeal membrane oxygenation. The use of HTK-Custodiol solution significantly improved midterm survival (Custodiol versus St-Thomas: hazard ratio = 0.20, 95% confidence interval: 0.069-0.60, P = 0.004). This retrospective study comparing St-Thomas solution and HTK-Custodiol as myocardial protection during heart procurement showed that Custodiol improves outcomes after HTx, including postoperative inotropic score, rejection score, 30-day mortality and midterm survival

    Rescue of DNA damage after constricted migration reveals a mechano-regulated threshold for cell cycle.

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    Migration through 3D constrictions can cause nuclear rupture and mislocalization of nuclear proteins, but damage to DNA remains uncertain, as does any effect on cell cycle. Here, myosin II inhibition rescues rupture and partially rescues the DNA damage marker γH2AX, but an apparent block in cell cycle appears unaffected. Co-overexpression of multiple DNA repair factors or antioxidant inhibition of break formation also exert partial effects, independently of rupture. Combined treatments completely rescue cell cycle suppression by DNA damage, revealing a sigmoidal dependence of cell cycle on excess DNA damage. Migration through custom-etched pores yields the same damage threshold, with ∼4-µm pores causing intermediate levels of both damage and cell cycle suppression. High curvature imposed rapidly by pores or probes or else by small micronuclei consistently associates nuclear rupture with dilution of stiff lamin-B filaments, loss of repair factors, and entry from cytoplasm of chromatin-binding cGAS (cyclic GMP-AMP synthase). The cell cycle block caused by constricted migration is nonetheless reversible, with a potential for DNA misrepair and genome variation

    A joint physics and radiobiology DREAM team vision - Towards better response prediction models to advance radiotherapy.

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    Radiotherapy developed empirically through experience balancing tumour control and normal tissue toxicities. Early simple mathematical models formalized this practical knowledge and enabled effective cancer treatment to date. Remarkable advances in technology, computing, and experimental biology now create opportunities to incorporate this knowledge into enhanced computational models. The ESTRO DREAM (Dose Response, Experiment, Analysis, Modelling) workshop brought together experts across disciplines to pursue the vision of personalized radiotherapy for optimal outcomes through advanced modelling. The ultimate vision is leveraging quantitative models dynamically during therapy to ultimately achieve truly adaptive and biologically guided radiotherapy at the population as well as individual patient-based levels. This requires the generation of models that inform response-based adaptations, individually optimized delivery and enable biological monitoring to provide decision support to clinicians. The goal is expanding to models that can drive the realization of personalized therapy for optimal outcomes. This position paper provides their propositions that describe how innovations in biology, physics, mathematics, and data science including AI could inform models and improve predictions. It consolidates the DREAM team's consensus on scientific priorities and organizational requirements. Scientifically, it stresses the need for rigorous, multifaceted model development, comprehensive validation and clinical applicability and significance. Organizationally, it reinforces the prerequisites of interdisciplinary research and collaboration between physicians, medical physicists, radiobiologists, and computational scientists throughout model development. Solely by a shared understanding of clinical needs, biological mechanisms, and computational methods, more informed models can be created. Future research environment and support must facilitate this integrative method of operation across multiple disciplines

    Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam

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    We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.Comment: 14 pages, 12 figures. Submitted for publication to Physical Review

    Measurement of the muon decay spectrum with the ICARUS liquid Argon TPC

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    Examples are given which prove the ICARUS detector quality through relevant physics measurements. We study the muon decay energy spectrum from a sample of stopping muon events acquired during the test run of the ICARUS T600 detector. This detector allows the spatial reconstruction of the events with fine granularity, hence, the precise measurement of the range and dE/dx of the muon with high sampling rate. This information is used to compute the calibration factors needed for the full calorimetric reconstruction of the events. The Michel rho parameter is then measured by comparison of the experimental and Monte Carlo simulated muon decay spectra, obtaining rho = 0.72 +/- 0.06(stat.) +/- 0.08(syst.). The energy resolution for electrons below ~50 MeV is finally extracted from the simulated sample, obtaining (Emeas-Emc)/Emc = 11%/sqrt(E[MeV]) + 2%.Comment: 16 pages, 8 figures, LaTex, A4. Some text and 1 figure added. Final version as accepted for publication in The European Physical Journal

    Space Applications of the FLUKA Monte-Carlo Code: Lunar and Planetary Exploration

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    NASA has recognized the need for making additional heavy-ion collision measurements at the U.S. Brookhaven National Laboratory in order to support further improvement of several particle physics transport-code models for space exploration applications. FLUKA has been identified as one of these codes and we will review the nature and status of this investigation as it relates to high-energy heavy-ion physics

    IsoBED: a tool for automatic calculation of biologically equivalent fractionation schedules in radiotherapy using IMRT with a simultaneous integrated boost (SIB) technique

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    <p>Abstract</p> <p>Background</p> <p>An advantage of the Intensity Modulated Radiotherapy (IMRT) technique is the feasibility to deliver different therapeutic dose levels to PTVs in a single treatment session using the Simultaneous Integrated Boost (SIB) technique. The paper aims to describe an automated tool to calculate the dose to be delivered with the SIB-IMRT technique in different anatomical regions that have the same Biological Equivalent Dose (BED), i.e. IsoBED, compared to the standard fractionation.</p> <p>Methods</p> <p>Based on the Linear Quadratic Model (LQM), we developed software that allows treatment schedules, biologically equivalent to standard fractionations, to be calculated. The main radiobiological parameters from literature are included in a database inside the software, which can be updated according to the clinical experience of each Institute. In particular, the BED to each target volume will be computed based on the alpha/beta ratio, total dose and the dose per fraction (generally 2 Gy for a standard fractionation). Then, after selecting the reference target, i.e. the PTV that controls the fractionation, a new total dose and dose per fraction providing the same isoBED will be calculated for each target volume.</p> <p>Results</p> <p>The IsoBED Software developed allows: 1) the calculation of new IsoBED treatment schedules derived from standard prescriptions and based on LQM, 2) the conversion of the dose-volume histograms (DVHs) for each Target and OAR to a nominal standard dose at 2Gy per fraction in order to be shown together with the DV-constraints from literature, based on the LQM and radiobiological parameters, and 3) the calculation of Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) curve versus the prescribed dose to the reference target.</p
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