285 research outputs found

    Transmission of pillar-based photonic crystal waveguides in InP technology

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    Waveguides based on line defects in pillar photonic crystals have been fabricated in InP/InGaAsP/InP technology. Transmission measurements of different line defects are reported. The results can be explained by comparison with two-dimensional band diagram simulations. The losses increase substantially at mode crossings and in the slow light regime. The agreement with the band diagrams implies a good control on the dimensions of the fabricated features, which is an important step in the actual application of these devices in photonic integrated circuit

    Tbx5 is Required for Avian and Mammalian Epicardial Formation and Coronary Vasculogenesis.

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    Rationale: Holt-Oram syndrome (HOS) is an autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene. Overexpression of Tbx5 in the chick proepicardial organ (PEO) impaired coronary blood vessel formation. However, the potential activity of Tbx5 in the epicardium itself, and Tbx5\u27s role in mammalian coronary vasculogenesis, remains largely unknown. Objective: To evaluate the consequences of altered Tbx5 gene dosage during PEO and epicardial development in the embryonic chick and mouse. Methods and Results: Retroviral-mediated knockdown or upregulation of Tbx5 expression in the embryonic chick PEO as well as proepicardial-specific deletion of Tbx5 in the embryonic mouse (Tbx5(epi-/-)) impaired normal PEO cell development, inhibited epicardial and coronary blood vessel formation and altered developmental gene expression. The generation of epicardial-derived cells (EPDCs) and their migration into the myocardium was impaired between embryonic day (E) 13.5-15.5 in mutant hearts due to delayed epicardial attachment to the myocardium and subepicardial accumulation of EPDCs. This caused defective coronary vasculogenesis associated with impaired vascular smooth muscle cell recruitment, and reduced invasion of cardiac fibroblasts and endothelial cells into myocardium. In contrast to wildtype hearts that exhibited an elaborate ventricular vascular network, Tbx5(epi-/-) hearts displayed a marked decrease in vascular density that was associated with myocardial hypoxia as exemplified by HIF1α upregulation and increased binding of Hypoxyprobe-1. Tbx5(epi-/-) mice with such myocardial hypoxia exhibited reduced exercise capacity compared to wildtype mice. Conclusions: Our findings support a conserved Tbx5 dose-dependent requirement for both proepicardial and epicardial progenitor cell development in chick and mouse coronary vascular formation

    Re-Irradiation in Patients with Recurrent Rectal Cancer is Safe and Feasible

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    BACKGROUND: There is no consensus yet for the best treatment regimen in patients with recurrent rectal cancer (RRC). This study aims to evaluate toxicity and oncological outcomes after re-irradiation in patients with RRC in our center. Clinical (cCR) and pathological complete response (pCR) rates and radicality were also studied. METHODS: Between January 2010 and December 2018, 61 locally advanced RRC patients were treated and analyzed retrospectively. Patients received radiotherapy at a dose of 30.0-30.6 Gy (reCRT) or 50.0-50.4 Gy chemoradiotherapy (CRT) in cases of no prior irradiation because of low-risk primary rectal cancer. In both groups, patients received capecitabine concomitantly. RESULTS: In total, 60 patients received the prescribed neoadjuvant (chemo)radiotherapy followed by surgery, 35 patients (58.3%) in the reRCT group and 25 patients (41.7%) in the long-course CRT group. There were no significant differences in overall survival (p = 0.82), disease-free survival (p = 0.63), and local recurrence-free survival (p = 0.17) between the groups. Patients in the long-course CRT group reported more skin toxicity after radiotherapy (p = 0.040). No differences were observed in late toxicity. In the long-course CRT group, a significantly higher cCR rate was observed (p = 0.029); however, there was no difference in the pCR rate (p = 0.66). CONCLUSIONS: The treatment of RRC patients with re-irradiation is comparable to treatment with long-course CRT regarding toxicity and oncological outcomes. In the reCRT group, less cCR was observed, although there was no difference in pCR. The findings in this study suggest that it is safe and feasible to re-irradiate RRC patients

    A Counterexample to Claimed COBE Constraints on Compact Toroidal Universe Models

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    It has been suggested that if the Universe satisfies a flat, multiply connected, perturbed Friedmann-Lema^itre model, then cosmic microwave background data from the COBE satellite implies that the minimum size of the injectivity diameter (shortest closed spatial geodesic) must be larger than about two fifths of the horizon diameter. To show that this claim is misleading, a simple T2Ă—RT^2 \times R universe model of injectivity diameter a quarter of this size, i.e. a tenth of the horizon diameter, is shown to be consistent with COBE four year observational maps of the cosmic microwave background. This is done using the identified circles principle.Comment: 11 pages, 3 figures, accepted for Classical & Quantum Gravit

    Physiotherapy for Children with Functional Constipation:A Pragmatic Randomized Controlled Trial in Primary Care

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    Objective: To determine the effectiveness of physiotherapy plus conventional treatment compared with conventional treatment alone for the treatment of functional constipation in children age 4-17 years in primary care. Study design: Pragmatic randomized controlled trial with 8 months follow-up. Primary care physicians recruited children diagnosed with functional constipation (n = 234), and pediatricians recruited newly referred children with a diagnosis of functional constipation (n = 11). Conventional treatment comprised toilet training, nutritional advice, and laxative prescribing, whereas physiotherapy focused on resolving dyssynergic defecation. The primary outcome was treatment success over 8 months, defined as the absence of functional constipation (Rome III criteria) without laxative use. Secondary outcomes included the absence of functional constipation irrespective of continuation of laxative use and global perceived treatment effect. Results: Children were allocated to conventional treatment plus physiotherapy or conventional treatment alone (67 per group), mean (SD) age was 7.6 (3.5) years. Results of longitudinal analyses in the intention-to-treat population showed that the treatment success percentage was not statistically improved by adding physiotherapy to conventional treatment (adjusted relative risk [aRR] 0.80, 95% CI 0.44-1.30). At 4 months, fewer children receiving physiotherapy had treatment success (17%) than children receiving conventional treatment alone (28%), but this had equalized by 8 months (42% and 41%, respectively). The percentage of children without functional constipation, irrespective of continuation of laxative use, was not statistically different between groups over 8 months (aRR 1.12, 95% CI 0.82-1.34). Notably, parents reported significantly more global symptom improvement after physiotherapy than after conventional treatment (aRR 1.40; 95% CI 1.00-1.73). Conclusions: We find no evidence to recommend physiotherapy for all children with functional constipation in primary care. Trial registration: Netherlands Trial Registry: NTR4797

    Clinical selection strategy for and evaluation of intra-operative brachytherapy in patients with locally advanced and recurrent rectal cancer

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    Background and purpose: A radical resection of locally advanced rectal cancer (LARC) or recurrent rectal cancer (RRC) can be challenging. In case of increased risk of an R1 resection, intra-operative brachytherapy (IOBT) can be applied. We evaluated the clinical selection strategy for IOBT. Materials and methods: Between February 2007 and May 2018, 132 LARC/RRC patients who were scheduled for surgery with IOBT standby, were evaluated. By intra-operative inspection of the resection margin and MR imaging, it was determined whether a resection was presumed to be radical. Frozen sections were taken on indication. In case of a suspected R1 resection, IOBT (1 x 10 Gy) was applied. Histopathologic evaluation, treatment and toxicity data were collected from medical records. Results: Tumour was resected in 122 patients. IOBT was given in 42 patients of whom 54.8% (n = 23) had a histopathologically proven R1 resection. Of the 76 IOBT-omitted R0 resected patients, 17.1% (n = 13) had a histopathologically proven R1 resection. In 4 IOBT-omitted patients, a clinical R1/2 resection was seen. In total, correct clinical judgement occurred in 72.6% (n = 88) of patients. In LARC, 58.3% (n = 14) of patients were overtreated (R0, with IOBT) and 10.9% (n = 5) were undertreated (R1, without IOBT). In RRC, 26.5% (n = 9) of patients were undertreated. Conclusion: In total, correct clinical judgement occurred in 72.6% (n = 88). However, in 26.5% (n = 9) RRC patients, IOBT was unjustifiedly omitted. IOBT is accompanied by comparable and acceptable toxicity. Therefore, we recommend IOBT to all RRC patients at risk of an R1 resection as their salvage treatment. (c) 2021 The Author(s). Published by Elsevier B.V. Radiotherapy and Oncology 159 (2021) 91 & ndash;97 This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

    The Relation Between Histological, Tumor-Biological and Clinical Parameters in Deep and Superficial Leiomyosarcoma and Leiomyoma

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    Purpose: Leiomyosarcomas (LMS) of deep and superficial tissues were examined to identify prognostic markers explaining their different biological behaviour and to define differences between cutaneous and subcutaneous LMS. LMS and leiomyomas (LM) of the skin were compared to and consistent differences that could aid in the (sometimes difficult) diagnosis

    Reorganizing the Multidisciplinary Team Meetings in a Tertiary Centre for Gastro-Intestinal Oncology Adds Value to the Internal and Regional Care Pathways. A Mixed Method Evaluation

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    Introduction: The reorganisation of the structure of a Gastro-Intestinal Oncology Multidisciplinary Team Meeting (GIO-MDTM) in a tertiary centre with three care pathways is evaluated on added value. Methods: In a mixed method investigation, process indicators such as throughput times were analysed and stakeholders were interviewed regarding benefits and drawbacks of the reorganisation and current MDTM functioning. Results: For the hepatobiliary care pathway, the time to treatment plan increased, but the time to start treatment reduced significantly. The percentage of patients treated within the Dutch standard of 63 days increased for the three care pathways. From the interviews, three themes emerged: added value of MDTMs, focus on planning integrated care and awareness of possible improvements. Discussion: The importance of evaluating interventions in oncology care pathways is shown, including detecting unexpected drawbacks. The evaluation provides insight into complex dynamics of the care pathways and contributes with recommendations on functioning of an MDTM. Conclusions: Throughput times are only partly determined by oncology care pathway management, but have influence on the functioning of MDTMs. Process indicator information can help to reflect on integration of care in the region, resulting in an increase of patients treated within the Dutch standard

    Agricultural pastures challenge the attractiveness of natural saltmarsh for a migratory goose

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    Broad-scale land conversions and fertilizer use have dramatically altered the available staging area for herbivorous long-distance migrants. Instead of natural land, these birds rely increasingly on pastures for migratory fuelling and stopover, often conflicting with farming practices. To predict and manage birds’ future habitat use, the relative advantages and disadvantages of natural (e.g. saltmarsh, intertidal) versus anthropogenic staging sites for foraging need to be understood. We compared the migratory staging of brent geese on saltmarsh and pasture sites in spring. Food quality (nitrogen and fibre content), antagonistic behaviour, and body weight were quantified at nearby sites in simultaneous seasons. Individuals were tracked with high-resolution GPS and accelerometers to compare timing of migration and time budgets during fuelling. On pastures, birds rested more and experienced higher ingestion rates, similar or superior food quality and reduced antagonistic interactions than on saltmarsh. Brent geese using fertilized grasslands advanced their fuelling and migration schedules compared to those using saltmarsh. Pasture birds reached heavy weights earlier, departed sooner, and arrived in the Arctic earlier. Intertidal mudflats were frequently visited by saltmarsh birds during the day, and available food there (algae, some seagrass) was of higher quality than terrestrial resources. Availability of intertidal resources was an important factor balancing the otherwise more favourable conditions on pastures relative to saltmarsh. Synthesis and applications. Disadvantages of longer foraging effort, more antagonistic interactions and delayed fuelling schedules on traditional saltmarshes may cause geese to exchange this traditional niche in favour of pastures, especially in a warming climate that requires advancement of migratory schedules. However, due to its high quality, intertidal forage can complement terrestrial foraging, potentially removing the incentive for habitat switches to pastures. The relatively high quality of green algae and seagrass, and birds’ remarkable preference for these resources when available, provides a key for managers to create landscapes that can sustain this specialist’s intertidal lifestyle. To keep natural habitats attractive to staging geese with the purpose of preventing conflicts with farming practices, management actions should focus on conservation and restoration of saltmarsh and especially intertidal habitat.</p
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