3,388 research outputs found

    Phenol-formaldehyde intumescent coating composition and coating prepared therefrom

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    Intumescent coatings which form a thick, uniform, fine celled, low density foam upon exposure to a high intensity heat flux or flame are disclosed, the invention coatings comprise phenolic resin prepolymer containing a blowing agent and a nucleating agent; in the preferred embodiments the coatings also contains a silicone surfactant, the coatings are useful in thermal and fire protection systems

    Pion-Kaon Scattering near the Threshold in Chiral SU(2) Perturbation Theory

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    In the context of chiral SU(2) perturbation theory, pion-kaon scattering is analysed near the threshold to fourth chiral order. The scattering amplitude is calculated both in the relativistic framework and by using an approach similar to heavy baryon chiral perturbation theory. Both methods lead to equivalent results. We obtain relations between threshold parameters, valid to fourth chiral order, where all those combinations of low-energy constants which are not associated with chiral-symmetry breaking terms drop out. The remaining low-energy constants can be estimated using chiral SU(3) symmetry. Unfortunately, the experimental information is not precise enough to test our low-energy theorems.Comment: 38 pages, 5 figures, PhD Thesis, references adde

    Formation of Longitudinal River Valleys and the Fixing of Drainage Divides in Response to Exhumation of Crystalline Basement

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    Variations in rock strength act as a first‐order control on mountain landscapes. However, the transient topographic signal of basement exhumation has not been explored. We use model outputs to demonstrate the mobility of drainage divides in mountain ranges in response to the exhumation of basement rocks and the implications for the morphology of river catchments. The exhumation of harder rocks within a catchment reduces upstream channel steepness and erosion rates in contrast to neighbouring catchments. The results are a shift in the orogen‐scale drainage divide towards the harder rocks, and the formation of range parallel longitudinal valleys as neighbouring river networks capture the headwaters of catchments impacted by the harder lithology. Our model outputs provide a process explanation for the initiation of many longitudinal valleys in mountain ranges, and for the pinning of drainage divides on rocks of higher strength as seen the Central Pyrenees, Western Alps or High Atlas

    Fiberoptic Colonoscopic Polypectomies

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    The development of fiberoptic instruments which permit direct visualization of the entire colonic lumen has made possible the safe removal of polyps from any part of the colon. The avoidance of transabdominal colotomy and polypectomy significantly decreases the mortality and morbidity as well as the duration of hospital stay. We wish to present our experience in performing the endoscopic removal of 128 colonic polyps larger than 0.5 cm in size in 103 patients, located from the cecum to the sigmoid colon and beyond the reach of the rigid sigmoidoscope. The polypectomy procedures via the colonoscope were done without mortality and with only three relatively minor complications, all of which responded to conservative measures. Endoscopic removal of colonic polyps is proposed as a safe, practical alternative to either laparotomy and colotomy or repeated barium enema studies in the management of the patient with a colonic polyp

    No time to die: the consensus immunoscore for predicting survival and response to chemotherapy of locally advanced colon cancer patients in a multicenter international study.

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    The multicenter international Society for Immunotherapy of Cancer (SITC) study of the consensus Immunoscore demonstrated the prediction of survival and response to chemotherapy in 763 Stage III colon cancer (CC) patients. Similar Immunoscore groups were found in elderly patients, and densities of immune cells and intratumoral T-cell repertoire were not decreasing with age in the tumor microenvironment. In two independent cohorts, Immunoscore significantly predicted time to recurrence (TTR), disease-free survival (DFS), and overall survival (OS), including within high-risk (T4 or N2) and low-risk (T1-3, N1) patients. In stratified Cox multivariable analysis for TTR, DFS, and OS, Immunoscore\u27s association to outcomes was independent of the patient\u27s age, sidedness, gender, T-stage, N-stage, and microsatellite instability status. Furthermore, the relative contribution to the risk test showed that Immunoscore had the highest contribution to survival. Importantly Immunoscore predicted the likelihood of response to chemotherapy. Only patients with a high-Immunoscore significantly benefited from chemotherapy. The prognostic value of Immunoscore was confirmed in two independent phase 3 clinical trials (NCCTG-N0147, n = 559; Prodige-IDEA, n = 1062). Moreover, results from IDEA phase 3 randomized trial revealed the predictive value of Immunoscore for response to adjuvant FOLFOX chemotherapy duration. The latest edition of the WHO Digestive System Tumors classification introduced the immune response as measured by Immunoscore as essential and desirable diagnostic criteria for CC, and Immunoscore was introduced into the 2020 ESMO Clinical Practice Guidelines for CC to refine the prognosis and adjust chemotherapy decision-making process in stages II and III patients. These results highlight the clinical utility of Immunoscore

    A study to determine methods of improving the subsonic performance of a proposed Personnel Launch System (PLS) concept

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    An investigation has been conducted in the Langley 7- by 10-Foot High Speed Wind Tunnel to determine the longitudinal and lateral directional aerodynamic characteristics of a series of personnel launch system concepts. This series of configurations evolved during an effort to improve the subsonic characteristics of a proposed lifting entry vehicle (designated the HL-20). The primary purpose of the overall investigation was to provide a vehicle concept which was inherently stable and trimable from entry to landing while examining methods of improving subsonic aerodynamic performance

    Bedload‐Bedrock Contrasts Form Enigmatic Low‐Relief Surfaces of the Pyrenees

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    Low-relief, high-elevation surfaces in mountain belts highlight the dynamic nature of landscapes and have provided evidence for changes in tectonics and/or climate. Yet quantifying when changes occurred from topographic data is challenging and relationships between erosion rate, lithology and precipitation are complex. In the Pyrenees, low-relief, high elevation surfaces are found across both plutonic massifs and the surrounding softer rocks and channel steepness values are relatively uniform between these lithologies. This suggests a weak relationship between erosion rate and lithology despite a clear relationship between the drainage network configuration and the location of the plutonic rocks. We explore this conflicting evidence for strength of the relationship between lithology and erosion rate using a landscape evolution model which accounts for the contrast between bedrock and bedload erodibility. This contrast produces dispersed channel steepness values and predicts the in situ development of low-relief surfaces, under steady forcing conditions

    Functional MRI To Evaluate “Sense of Self” following Perforator Flap Breast Reconstruction

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    Background: Breast reconstruction is associated with high levels of patient satisfaction. Previous patient satisfaction studies have been subjective. This study utilizes functional magnetic resonance imaging (fMRI) to objectively evaluate “sense of self” following deep inferior epigastric perforator (DIEP) flap breast reconstruction in an attempt to better understand patient perception. Methods: Prospective fMRI analysis was performed on four patients before and after delayed unilateral DIEP flap breast reconstruction, and on four patients after immediate unilateral DIEP flap breast reconstruction. Patients were randomly cued to palpate their natural breast, mastectomy site or breast reconstruction, and external silicone models. Three regions of interest (ROIs) associated with self-recognition were examined using a general linear model, and compared using a fixed effects and random effects ANOVA, respectively. Results: In the delayed reconstruction group, activation of the ROIs was significantly lower at the mastectomy site compared to the natural breast (p<0.01). Ten months following reconstruction, activation of the ROIs in the reconstructed breast was not significantly different from that observed with natural breast palpation. In the immediate reconstruction group, palpation of the reconstructed breast was also similar to the natural breast. This activity was greater than that observed during palpation of external artificial models (p<0.01). Conclusions: Similar activation patterns were observed during palpation of the reconstructed and natural breasts as compared to the non-reconstructed mastectomy site and artificial models. The cognitive process represented by this pattern may be a mechanism by which breast reconstruction improves self-perception, and thus patient satisfaction following mastectomy
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