88 research outputs found

    Model-based design of MADIX under bulk and solution conditions

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    Macromolecular design by interchange of xanthates (MADIX) is a less studied controlled radical polymerization technique from a mechanistic and modeling point of view. In this contribution, MADIX of styrene and chain extension toward the synthesis of block copolymers is investigated, with azobisisobutyronitrile as conventional radical initiator and O-ethylxanthyl ethyl propionate as initial RAFT agent (R0X). Degenerative transfer coefficients for both the exchange with R0X and macro-RAFT agent are reported and their difference is highlighted to be relevant for the kinetic description. The model validity is supported by measurement of end-group functionality (EGF) data considering elemental analysis. Novel mechanistic insights are that in contrast to typical reversible addition fragmentation chain transfer (RAFT) polymerizations the macroradical CLD follows a Schulz-Flory distribution and that both during the homopolymerization and the chain extensions an exchange, so with monomer incorporation, only takes place once [1]. [1] D.J.G. Devlaminck, P.H.M. Van Steenberge, M.-F. Reyniers, D.R. D’hooge, Polym Chem. 2017, 8, 694

    The role of grassland sward islets in the distribution of arthropods in cattle pastures

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    1. It is well documented that cattle reduce their grazing activity in the vicinity of cattle dung, which gives rise to distinct patches, or islets as they have been termed, of longer sward. The influence of such islets on pasture utilisation and agronomic performance has been widely studied, but very little information is available concerning their influence on grassland biodiversity. 2. In this study the abundance and distribution of arthropods in relation to islets was assessed, using suction sampling, at 26 commercial farms and in a replicated pasture management experiment in the south and east of Ireland. 3. Islets were found to cover approximately 24% of pastures and to contain between 40% and 50% of arthropod individuals. 4. Islets consistently contained a higher density of arthropods, even when the difference in mean sward height between islets and more strongly grazed sward was accounted for. The relative concentration of arthropods in islets declined with increasing mean sward height, which may be related to the recovery of well-grazed non-islet sward. Islets appear to act as refugia from sward removal. 5. The potential importance of islets in maintaining arthropod biodiversity within intensively grazed pastures and the wider grass-based farming landscape is discussed, particularly with reference to standard agronomic practices such as sward topping and chain harrowing, which aim to remove the sward heterogeneity created by grazing livestock

    Pharmacodynamic and Clinical Results from a Phase I/II Study of the HSP90 Inhibitor Onalespib in Combination with Abiraterone Acetate in Prostate Cancer.

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    PURPOSE:Onalespib is a potent, fragment-derived second-generation HSP90 inhibitor with preclinical activity in castration-resistant prostate cancer (CPRC) models. This phase I/II trial evaluated onalespib in combination with abiraterone acetate (AA) and either prednisone or prednisolone (P) in men with CRPC progressing on AA/P. PATIENTS AND METHODS:Patients with progressing CRPC were randomly assigned to receive 1 of 2 regimens of onalespib combined with AA/P. Onalespib was administered as intravenous infusion starting at 220 mg/m2 once weekly for 3 of 4 weeks (regimen 1); or at 120 mg/m2 on day 1 and day 2 weekly for 3 of 4 weeks (regimen 2). Primary endpoints were response rate and safety. Secondary endpoints included evaluation of androgen receptor (AR) depletion in circulating tumor cells (CTC) and in fresh tumor tissue biopsies. RESULTS:Forty-eight patients were treated with onalespib in combination with AA/P. The most common ≥grade 3 toxicities related to onalespib included diarrhea (21%) and fatigue (13%). Diarrhea was dose limiting at 260 and 160 mg/m2 for regimens 1 and 2, respectively. Transient decreases in CTC counts and AR expression in CTC were observed in both regimens. HSP72 was significantly upregulated following onalespib treatment, but only a modest decrease in AR and GR was shown in paired pre- and posttreatment tumor biopsy samples. No patients showed an objective or PSA response. CONCLUSIONS:Onalespib in combination with AA/P showed mild evidence of some biological effect; however, this effect did not translate into clinical activity, hence further exploration of this combination was not justified

    Joint hypermobility in children with idiopathic scoliosis: SOSORT award 2011 winner

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    <p>Abstract</p> <p>Background</p> <p>Generalized joint hypermobility (JHM) refers to increased joint mobility with simultaneous absence of any other systemic disease. JHM involves proprioception impairment, increased frequency of pain within joints and tendency to injure soft tissues while performing physical activities. Children with idiopathic scoliosis (IS) often undergo intensive physiotherapy requiring good physical capacities. Further, some physiotherapy methods apply techniques that increase joint mobility and thus may be contraindicated.</p> <p>The aim of this paper was to assess JHM prevalence in children with idiopathic scoliosis and to analyze the relationship between JHM prevalence and the clinical and radiological parameters of scoliosis. The methods of assessment of generalized joint hypermobility were also described.</p> <p>Materials and methods</p> <p>This case-control study included 70 subjects with IS, aged 9-18 years (mean 13.2 ± 2.2), Cobb angle range 10°-53° (mean 24.3 ± 11.7), 34 presenting single curve thoracic scoliosis and 36 double curve thoracic and lumbar scoliosis. The control group included 58 children and adolescents aged 9-18 years (mean 12.6 ± 2.1) selected at random. The presence of JHM was determined using Beighton scale complemented with the questionnaire by Hakim and Grahame. The relationship between JHM and the following variables was evaluated: curve severity, axial rotation of the apical vertebra, number of curvatures (single versus double), number of vertebrae within the curvature (long versus short curves), treatment type (physiotherapy versus bracing) and age.</p> <p>Statistical analysis was performed with Statistica 8.1 (StatSoft, USA). The Kolmogorov-Smirnov test, U Mann-Whitney test, Chi<sup>2 </sup>test, Pearson and Spermann correlation rank were conducted. The value <it>p </it>= 0.05 was adopted as the level of significance.</p> <p>Results</p> <p>JHM was diagnosed in more than half of the subjects with idiopathic scoliosis (51.4%), whilst in the control group it was diagnosed in only 19% of cases (<it>p </it>= 0.00015). A significantly higher JHM prevalence was observed in both girls (<it>p </it>= 0.0054) and boys (<it>p </it>= 0.017) with IS in comparison with the corresponding controls. No significant relation was found between JHM prevalence and scoliosis angular value (<it>p </it>= 0.35), apical vertebra rotation (<it>p </it>= 0.86), the number of vertebrae within curvature (<it>p </it>= 0.8), the type of applied treatment (<it>p </it>= 0.55) and the age of subjects (<it>p </it>= 0.79). JHM prevalence was found to be higher in children with single curve scoliosis than in children with double curve scoliosis (<it>p </it>= 0.03).</p> <p>Conclusions</p> <p>JHM occurs more frequently in children with IS than in healthy sex and age matched controls. No relation of JHM with radiological parameters, treatment type and age was found. Systematically searched in IS children, JHM should be taken into account when physiotherapy is planned.</p

    Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

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    [This corrects the article DOI: 10.1186/s13054-016-1208-6.]
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