4,862 research outputs found

    On local structures of cubicity 2 graphs

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    A 2-stab unit interval graph (2SUIG) is an axes-parallel unit square intersection graph where the unit squares intersect either of the two fixed lines parallel to the XX-axis, distance 1+ϔ1 + \epsilon (0<ϔ<10 < \epsilon < 1) apart. This family of graphs allow us to study local structures of unit square intersection graphs, that is, graphs with cubicity 2. The complexity of determining whether a tree has cubicity 2 is unknown while the graph recognition problem for unit square intersection graph is known to be NP-hard. We present a polynomial time algorithm for recognizing trees that admit a 2SUIG representation

    Real-time national GPS networks: Opportunities for atmospheric sensing

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    Real-time national Global Positioning System (GPS) networks are being established in a number of countries for atmospheric sensing. UCAR, in collaboration with participating universities, is developing one of these networks in the United States. The network, named "SuomiNet" to honor meteorological satellite pioneer Verner Suomi, is funded by the U.S. National Science Foundation. SuomiNet will exploit the recently-shown ability of ground-based GPS receivers to make thousands of accurate upper and lower atmospheric measurements per day. Phase delays induced in GPS signals by the ionosphere and neutral atmosphere can be measured with high precision simultaneously along up to a dozen GPS ray paths in the field of view. These delays can be converted into total electron content (TEC), and integrated water vapor (if surface pressure data or estimates are available), along each GPS ray path. The resulting continuous, accurate, all-weather, real-time upper and lower atmospheric data create a variety of opportunities for atmospheric research. In this letter we describe SuomiNet, its applications, and the opportunity to coordinate national real-time GPS networks to create, a global network with larger scientific and operational potential. Copy right© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences

    Management of pouch dysfunction in a tertiary centre

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    AIM: Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis is the operation of choice for ulcerative colitis (UC) and some cases of familial adenomatous polyposis (FAP). Offering improvement in quality of life and high patient satisfaction, pouch surgery is also associated with significant morbidity. The aim of this study was to describe the management of patients referred to a tertiary centre with pouch dysfunction. METHOD: All patients referred with pouch dysfunction from other institutions, between October 2006 and November 2014, were included in this retrospective study. Information regarding initial diagnosis before RPC, type of procedure, symptoms leading to referral, relation of the appearance of symptom to the ileostomy closure, investigations, final diagnosis, treatment and follow-up was reviewed. RESULTS: One hundred and twenty one patients were included, having RPC mostly for UC (94%), and with diverting ileostomy (83%). The most frequent reasons for referral were high frequency of defaecation in 83 (69%) patients, abdominal pain and incontinence in 45 (37%) each and perianal pain in 44 (36%). The principal investigations performed were pouchoscopy in 97 (80%) patients, examination under anaesthesia (EUA) in 62 (51%), pelvic magnetic resonance imaging (MRI) in 56 (46%) and contrast radiology of the pouch (pouchogram) in 45 (35%). The commonest diagnoses were pouchitis (primary and secondary) in 24 (21%) patients and anastomotic leakage in 26 (22%). After full investigation a cause for the symptoms could not be found in 24 (20%) patients, resulting in the diagnosis of exclusion of 'irritable pouch syndrome' or functional disorder. Treatments given were long term antibiotic therapy in 29 (25%) patients, ileostomy in 19 (16%), use of a Medena catheter to promote anal evacuation in 17 (15%) and dilatation of a stenosis under anaesthetic in12 (10%). Six (5%) patients underwent major revision surgery of the pouch with a defunctioning ileostomy and the pouch was excised in another 6 (5%). CONCLUSION: Patients with ileoanal pouch dysfunction often have multiple symptoms. This study shows that a wide range of investigations and treatment modalities need to be available to manage such patients, with a specialised approach in a multidisciplinary setting. This article is protected by copyright. All rights reserved

    A prospective case control study of functional outcomes and related quality of life after colectomy for neoplasia.

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    AIM: Our aim was to assess bowel function and its effect on overall quality of life (QOL) when compared to healthy controls after colectomy. METHODS: Patients undergoing resection of colorectal neoplasia were recruited pre-operatively and followed up at 6 and 12 months, to assess 'early' bowel function. Patients who underwent surgery 2 to 4 years previously were recruited for assessment of 'intermediate' bowel function. Healthy relatives were recruited as controls. The Memorial Sloan-Kettering Cancer Centre and EQ-5D questionnaires were used to assess bowel function and QOL, respectively. Statistical assessment included regression analyses, parametric and non-parametric tests. The association between QOL and Memorial Sloan-Kettering Cancer Centre (MSKCC) scores was evaluated using Spearman's rank correlation. RESULTS: Ninety-one patients were recruited for assessment of 'early' and 85 for 'intermediate' bowel function. There were 85 controls. Patients had a significantly higher number of bowel movements at each follow-up (p < 0.001). At 12 months after surgery, patients reported difficulty with gas-stool discrimination. The 'intermediate' group were found to have lower scores for flatus control (<0.001) and total frequency score (p 0.03), indicating worse function. Patients with higher total MSKCC scores, no symptoms of urgency and those able to control flatus reported better QOL (p 0.006, 0.007 and 0.005, respectively) at 6 and 12 months. Gas-stool differentiation and complete evacuation correlated with better QOL in the 'intermediate' bowel function group (p 0.02 and 0.02, respectively). CONCLUSION: Colonic resection adversely affects elements of bowel function up to 4 years after surgery. Good colonic function, represented by higher MSKCC scores, correlates with better QOL

    Familial adenomatous patients with desmoid tumours show increased expression of miR-34a in serum and high levels in tumours

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    Familial adenomatous polyposis (FAP) is rare affecting 1 in 10,000 people and a subset (10%) are at risk of myofibroblastic desmoid tumours (DTs) after colectomy to prevent cancer. DTs are a major cause of morbidity and mortality. The absence of markers to monitor progression and a lack of treatment options are significant limitations to clinical management. We investigated microRNAs (miRNA) levels in DTs and serum using expression array analysis on two independent cohorts of FAP patients (total, n=24). Each comprised equal numbers of patients who had formed DTs (cases) and those who had not (controls). All controls had absence of DTs confirmed by clinical and radiological assessment over at least three years post- colectomy. Technical qPCR validation was performed using an expanded cohort (29 FAP patients; 16 cases and 13 controls). The most significant elevated serum miRNA marker of DTs was miR-34a-5p and in-situ hybridisation (ISH) showed most DTs analysed (5/6) expressed miRNA-34a-5p. Exome sequencing of tumour and matched germline DNA did not detect mutations within the miR-34a-5p transcript sites or 3'-UTR of target genes that would alter functional miRNA activity. In conclusion, miR-34a-5p is a potential circulatory marker and therapy target. A large prospective world-wide multi-centre study is now warranted

    Collaborative Gaze Channelling for Improved Cooperation During Robotic Assisted Surgery

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    The use of multiple robots for performing complex tasks is becoming a common practice for many robot applications. When different operators are involved, effective cooperation with anticipated manoeuvres is important for seamless, synergistic control of all the end-effectors. In this paper, the concept of Collaborative Gaze Channelling (CGC) is presented for improved control of surgical robots for a shared task. Through eye tracking, the fixations of each operator are monitored and presented in a shared surgical workspace. CGC permits remote or physically separated collaborators to share their intention by visualising the eye gaze of their counterparts, and thus recovers, to a certain extent, the information of mutual intent that we rely upon in a vis-à-vis working setting. In this study, the efficiency of surgical manipulation with and without CGC for controlling a pair of bimanual surgical robots is evaluated by analysing the level of coordination of two independent operators. Fitts' law is used to compare the quality of movement with or without CGC. A total of 40 subjects have been recruited for this study and the results show that the proposed CGC framework exhibits significant improvement (p<0.05) on all the motion indices used for quality assessment. This study demonstrates that visual guidance is an implicit yet effective way of communication during collaborative tasks for robotic surgery. Detailed experimental validation results demonstrate the potential clinical value of the proposed CGC framework. © 2012 Biomedical Engineering Society.link_to_subscribed_fulltex
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