186 research outputs found

    A robust data cleaning procedure for eddy covariance flux measurements

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    Abstract. The sources of systematic error responsible for introducing significant biases in the eddy covariance (EC) flux computation are manifold, and their correct identification is made difficult by the lack of reference values, by the complex stochastic dynamics, and by the high level of noise characterizing raw data. This work contributes to overcoming such challenges by introducing an innovative strategy for EC data cleaning. The proposed strategy includes a set of tests aimed at detecting the presence of specific sources of systematic error, as well as an outlier detection procedure aimed at identifying aberrant flux values. Results from tests and outlier detection are integrated in such a way as to leave a large degree of flexibility in the choice of tests and of test threshold values, ensuring scalability of the whole process. The selection of best performing tests was carried out by means of Monte Carlo experiments, whereas the impact on real data was evaluated on data distributed by the Integrated Carbon Observation System (ICOS) research infrastructure. Results evidenced that the proposed procedure leads to an effective cleaning of EC flux data, avoiding the use of subjective criteria in the decision rule that specifies whether to retain or reject flux data of dubious quality. We expect that the proposed data cleaning procedure can serve as a basis towards a unified quality control strategy for EC datasets, in particular in centralized data processing pipelines where the use of robust and automated routines ensuring results reproducibility constitutes an essential prerequisite

    Ena/VASP Enabled is a highly processive actin polymerase tailored to self-assemble parallel-bundled F-actin networks with Fascin

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    Enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) proteins are required for the formation and maintenance of filopodia, finger-like projections at the leading edge of migrating cells that are composed of parallel actin filaments bundled by Fascin. We imaged individual fluorescently labeled Drosophila Ena molecules on both single and Fascin-bundled actin filaments in vitro. Ena stimulates actin assembly by remaining continuously associated with the barbed end and increasing the elongation rate by approximately two- to threefold. Remarkably, the frequency and length of Ena’s processive runs are enhanced on filaments within a Fascin bundle, which drives a positive feedback cycle that allows the assembly of uniformly thick filopodia-like F-actin bundles composed of multiple filaments with aligned ends

    Enabled Negatively Regulates Diaphanous-Driven Actin Dynamics In Vitro and In Vivo

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    Actin regulators facilitate cell migration by controlling cell protrusion architecture and dynamics. As the behavior of individual actin regulators becomes clear, we must address why cells require multiple regulators with similar functions and how they cooperate to create diverse protrusions. We characterized Diaphanous (Dia) and Enabled (Ena) as a model, using complementary approaches: cell culture, biophysical analysis, and Drosophila morphogenesis. We found that Dia and Ena have distinct biochemical properties that contribute to the different protrusion morphologies each induces. Dia is a more processive, faster elongator, paralleling the long, stable filopodia it induces in vivo, while Ena promotes filopodia with more dynamic changes in number, length, and lifetime. Acting together, Ena and Dia induce protrusions distinct from those induced by either alone, with Ena reducing Dia-driven protrusion length and number. Consistent with this, EnaEVH1 binds Dia directly and inhibits DiaFH1FH2-mediated nucleation in vitro. Finally, Ena rescues hemocyte migration defects caused by activated Dia

    Abelson kinase acts as a robust, multifunctional scaffold in regulating embryonic morphogenesis

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    Abelson family kinases (Abl) are key regulators of cell behavior and the cytoskeleton during development and in leukemia. Abl's SH3, SH2, and tyrosine kinase domains are joined via a linker to an F-actin-binding domain (FABD). Research on Abl's roles in cell culture led to several hypotheses for its mechanism of action: 1) Abl phosphorylates other proteins, modulating their activity. 2) Abl directly regulates the cytoskeleton via its cytoskeletal interaction domains, and/or 3) Abl is a scaffold for a signaling complex. The importance of these roles during normal development remains untested. We tested these mechanistic hypotheses during Drosophila morphogenesis using a series of mutants to examine Abl's many cell biological roles. Strikingly, Abl lacking the FABD fully rescued morphogenesis, cell shape change, actin regulation, and viability, while kinase dead Abl, though reduced in function, retained substantial rescuing ability in some but not all Abl functions. We also tested the function of four conserved motifs in the linker region, revealing a key role for a conserved PXXP motif known to bind Crk and Abi. We propose Abl acts as a robust multi-domain scaffold with different protein motifs and activities contributing differentially to diverse cellular behaviors

    Carboplatin plus paclitaxel in extensive small cell lung cancer: a multicentre phase 2 study

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    A multicentre phase 2 trial (single-stage design) was undertaken to test the efficacy and toxicity of carboplatin (AUC 6 according to Calvert) plus paclitaxel (175 mg/m23-h infusion) every 4 weeks in the first line treatment of patients affected by extensive small cell lung cancer. The primary end-point of the trial was the objective response rate. 31 objective responses among 50 patients were considered necessary to proceed to a phase 3 trial. 48 patients were enrolled (median age 59 years). Treatment was very well tolerated. 3 patients (6.2%) had a complete response and 23 (47.9%) a partial response, for an overall response rate of 54.2% (95% CI: 39.2–68.6) Median time to progression was 5.7 months (95% CI: 5.2–6.2). Median survival was 9.6 months (95% CI: 7.2–14.6), with a median follow-up time of alive patients of 12 months. At 1 year, the probability of being progression-free or alive was 0.16 and 0.43, respectively. In conclusion, carboplatin plus paclitaxel as given in the present study is very well tolerated but not sufficiently active to warrant phase 3 comparison with standard chemotherapy regimens. © 2001 Cancer Research Campaign http://www.bjcancer.co

    A literature review on surgery for cervical vagal schwannomas

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    Cervical vagal schwannoma is a benign, slow-growing mass, often asymptomatic, with a very low lifetime risk of malignant transformation in general population, but diagnosis is still a challenge. Surgical resection is the treatment of choice even if its close relationship with nerve fibres, from which it arises, threats vagal nerve preservation. We present a case report and a systematic review of literature. All studies on surgical resection of cervical vagal schwannoma have been reviewed. Papers matching the inclusion criteria (topic on surgical removal of cervical vagal schwannoma, English language, full text available) were selected. Fifty-three patients with vagal neck schwannoma submitted to surgery were identified among 22 studies selected. Female/male ratio was 1.5 and median age 44 years. Median diameter was 5 cm (range 2 to 10). Most schwannoma were asymptomatic (68.2%) and received an intracapsular excision (64.9%). Postoperative symptoms were reported in 22.6% of patients. Cervical vagal schwannoma is a benign pathology requiring surgical excision, but frequently postoperative complications can affect patients lifelong, so, surgical indications should be based carefully on the balance between risks and benefits

    Lung volume reduction surgery versus endobronchial valves: a randomised controlled trial

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    BACKGROUND: Lung volume reduction surgery (LVRS) and bronchoscopic lung volume reduction (BLVR) with endobronchial valves can improve outcomes in appropriately selected patients with emphysema. However, no direct comparison data exist to inform clinical decision making in people who appear suitable for both procedures. Our aim was to investigate whether LVRS produces superior health outcomes when compared with BLVR at 12 months. METHODS: This multicentre, single-blind, parallel-group trial randomised patients from five UK hospitals, who were suitable for a targeted lung volume reduction procedure, to either LVRS or BLVR and compared outcomes at 1 year using the i-BODE score. This composite disease severity measure includes body mass index, airflow obstruction, dyspnoea and exercise capacity (incremental shuttle walk test). The researchers responsible for collecting outcomes were masked to treatment allocation. All outcomes were assessed in the intention-to-treat population. RESULTS: 88 participants (48% female, mean±sd age 64.6±7.7 years, forced expiratory volume in 1 s percent predicted 31.0±7.9%) were recruited at five specialist centres across the UK and randomised to either LVRS (n=41) or BLVR (n=47). At 12 months follow-up, the complete i-BODE was available in 49 participants (21 LVRS/28 BLVR). Neither improvement in the i-BODE score (LVRS -1.10±1.44 versus BLVR -0.82±1.61; p=0.54) nor in its individual components differed between groups. Both treatments produced similar improvements in gas trapping (residual volume percent predicted: LVRS -36.1% (95% CI -54.6- -10%) versus BLVR -30.1% (95% CI -53.7- -9%); p=0.81). There was one death in each treatment arm. CONCLUSION: Our findings do not support the hypothesis that LVRS is a substantially superior treatment to BLVR in individuals who are suitable for both treatments
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