567 research outputs found

    Learning Graph Embeddings for Open World Compositional Zero-Shot Learning

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    Compositional Zero-Shot learning (CZSL) aims to recognize unseen compositions of state and object visual primitives seen during training. A problem with standard CZSL is the assumption of knowing which unseen compositions will be available at test time. In this work, we overcome this assumption operating on the open world setting, where no limit is imposed on the compositional space at test time, and the search space contains a large number of unseen compositions. To address this problem, we propose a new approach, Compositional Cosine Graph Embeddings (Co-CGE), based on two principles. First, Co-CGE models the dependency between states, objects and their compositions through a graph convolutional neural network. The graph propagates information from seen to unseen concepts, improving their representations. Second, since not all unseen compositions are equally feasible, and less feasible ones may damage the learned representations, Co-CGE estimates a feasibility score for each unseen composition, using the scores as margins in a cosine similarity-based loss and as weights in the adjacency matrix of the graphs. Experiments show that our approach achieves state-of-the-art performances in standard CZSL while outperforming previous methods in the open world scenario

    Retinoblastoma and vision

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    The assessment of vision has a growing importance in the management of retinoblastoma in the era of globe-conserving therapy, both prior to and after treatment. As survival rates approach 98-99% and globe salvage rates reach ever-higher levels, it is important to provide families with information regarding the visual outcomes of different treatments. We present an overview of the role of vision in determining the treatment given and the impact of complications of treatment. We also discuss screening and treatment strategies that can be used to maximise vision

    Constrictive pericarditis presenting as chylothorax

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    Chylothorax is a rare clinical condition that can be attributed to a damaged thoracic duct. The condition is suggested by aspiration of milky white fluid from the pleural cavity and is commonly associated with either malignant diseases or trauma (e.g. cardiothoracic surgery). We present the case of a 15-year-old boy with chylothorax, whose effusion was due to constrictive pericarditis. The definitive treatment of chylothorax involves identification and management of the underlying pathology. We suggest that when dealing with cases of chylothorax, constrictive pericarditis should be considered among the causes

    Sclero-conjunctival ischaemia secondary to intra-arterial chemotherapy for retinoblastoma

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    PURPOSE Intra-arterial chemotherapy (IAC), delivered directly to the globe via the internal carotid artery is now an established treatment for retinoblastoma. We report a case of anterior segment ischaemia following treatment with multiple intra-arterial chemotherapy (IAC) infusions. OBSERVATIONS A 5 month old female presented with bilateral retinoblastoma and was treated with 12 infusions of IAC. Her right eye was enucleated at diagnosis. After her seventh IAC treatment, she developed ipsilateral sixth and third cranial nerve palsies. After the twelfth IAC, she developed an area of conjunctival and scleral ischaemia between 12 and 3 o'clock meridians in her left eye. However, she maintained visual acuity of LogMAR 0.34. CONCLUSIONS AND IMPORTANCE The median number of IAC treatments in large studies is three. It is possible that repeated doses of IAC have an accumulative negative effect on the ocular blood supply, risking anterior segment and neurologic sequelae. This case highlights the significant challenge of balancing the salvage of eyes and vision with the potentially significant morbidity associated with IAC

    Helicobacter pylori: association with gall bladder disorders in Pakistan

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    Helicobacter species colonise the biliary tract and therefore this study explores the relationship between of Helicobacter pylori and cholecystitis. Bile and gall bladder tissue samples were obtained from 144 Patients who underwent cholecystectomy. Of these, 89 had chronic cholecystitis with cholelithiasis, 44 had gall bladder carcinoma and 11 had gall bladder polyps. Histopathology examination included special staining and immunohistochemistry (IHC), while Helicobacter species (H. pylori, H. bilis and H. hepaticus) were detected by the polymerase chain reaction (PCR). Sequencing and BLAST query of PCR products was undertaken and samples were considered to contain H. pylori if both PCR and IHC were positive. Immunohistochemistry for H. pylori was positive in 22 (25%) cases compared to five (9%) in the control group (P=0.02). Testing (PCR) for 16S rDNA was positive in 23 (26%) cases compared to six (11%) controls (P=0.03). Negative PCR results were obtained for H. bilis and H. hepaticus. Twenty-four (89%) were positive by both 16S rDNA PCR and IHC for H. pylori (

    Number, frequency and time interval of examinations under anesthesia in bilateral retinoblastoma

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    PURPOSE: Current practice in retinoblastoma (Rb) has transformed this malignancy into a curable disease. More attention should therefore be given to quality of life considerations, including measures related to examinations under anesthesia (EUAs). We aimed to investigate EUA measures in bilateral Rb patients and compare the findings to EUAs in unilateral Rb. METHODS: A retrospective analysis of bilateral Rb patients that presented to the London Rb service from 2006 to 2013, were treated and had long-term follow-up. RESULTS: A total of 62 Rb patients, 15 (24.2%) of which had International Intraocular Retinoblastoma Classification (IIRC) group A/B/no Rb at presentation, 26 (41.9%) C/D, and 21 (33.9%) were E in at least one eye. The mean number of EUAs was 35.8 ± 21.5, mean time from first to last EUA was 50.6 ± 19.9 months, and mean EUA frequency was 0.715 ± 0.293 EUAs/month. IIRC group was found not to correlate with any of the EUA measures. Age at presentation inversely correlated with time interval from first to last EUA and to EUA frequency (p ≤ 0.029). Rb family history correlated with the latter measure (p = 0.005) and intraophthalmic artery chemotherapy and brachytherapy correlated with all EUA measures (p ≤ 0.029). Mean follow-up time was 80.1 ± 24.3 months. When compared with a previously reported cohort of unilateral Rb, the present group underwent 3× more EUAs (p < 0.001) over nearly double the time (p < 0.001). CONCLUSIONS: Families should be counselled on anticipated EUA burden associated with bilateral Rb. In this respect, age at presentation and family history were found to have a predictive role, whereas IIRC group did not

    Reduction of severe visual loss and complications following intra-arterial chemotherapy (IAC) for refractory retinoblastoma.

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    BACKGROUND: Intra-arterial chemotherapy (IAC) for retinoblastoma has been documented as causing visual loss and ocular motility problems. A lack of safety data has precluded its acceptance in all centres. METHODS: Retrospective cohort study of patients with retinoblastoma from 2013 to 2015 who had a healthy foveola and relapsed following systemic chemotherapy. All required IAC. The correlation of complications with doses of melphalan +/- topotecan used and putative catheterisation complications was assessed. Ocular complications were determined using vision, macular (including pattern visual evoked potentials (PVEPs)), retinal electroretinograms (ERGs) and ocular motility functions. Efficacy (tumour control) was also assessed. RESULTS: All eyes had age appropriate doses of melphalan with five having additional doses of topotecan. Severe physiological reactions requiring adrenaline were seen in six patients during the catheterisation procedure. Difficulty was documented in accessing the ophthalmic artery in 7/27 catheterisations. The median/mean number of courses of chemotherapy was three. No child had severe visual loss as assessed by age appropriate tests (median follow-up 20.9 months, range 3.7-35.2 months). One child had nasal choroidal ischaemia and a sixth nerve palsy. Post-IAC PVEPs were performed in eight and reported as normal. All post-IAC ERGs were normal apart from one (total dose 20 mg melphalan 0.8 mg topotecan). Tumour control was achieved in six of nine cases. CONCLUSION: The proportion of visual and ocular motility complications may be reduced by providing age-adjusted doses of melphalan. Dose rather than complications from catheterisation is the most important risk factor for ocular injury

    Robust Adaptive Control of an Uninhabited Surface Vehicle

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    In this paper, we develop a novel and robust adaptive autopilot for uninhabited surface vehicles (USV). In practice, usually asudden change in dynamics results in aborted missions and the USV has to be rescued to avoid possible damage to other marine crafts inthe vicinity. This problem has been investigated in our innovative design, which enables the autopilot to cope well with significant changes in the system dynamics and empowers USVs to accomplish their desired missions. The model predictivecontrol technique is employed which adopts an online adaptive nature by utilising three algorithms. Even with random initialisation,significant improvements over the gradient descent and least squares approaches have been achieved by the modified weightedleast squares (WLS) method, which periodically reinitialising the covariance matrix. Extensive simulation studies have been performed to test and verify the advantages of the proposed method

    Long-term Visual Acuity, Strabismus, and Nystagmus Outcomes Following Multimodality Treatment in Group D Retinoblastoma Eyes

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    PURPOSE: To analyze the long-term visual acuity, strabismus, and nystagmus outcomes in Group D retinoblastoma following multimodality treatments in a national retinoblastoma referral center. DESIGN: Retrospective interventional case series. METHODS: A 13-year retrospective chart review of Group D eyes treated initially with intravenous chemotherapy (IVC) and followed up for at least 1 year from last treatment. Risk factors for final visual acuity (VA) were analyzed, and rate of strabismus and nystagmus at last follow-up visit were calculated. RESULTS: One hundred and four Group D eyes (92 patients) presented to our center during the study period, of which 32 (27 patients) met the inclusion criteria. Following IVC (vincristine, etoposide, and carboplatin), adjuvant treatments included intraophthalmic artery chemotherapy in 5 (16%) eyes, plaque brachytherapy in 5 (16%), transpupillary thermotherapy (TTT) in 18 (56%), and cryotherapy in 24 (75%) eyes. On last examination, 64.41 ± 6.76 months from presentation, mean final VA was 20/283 (logMAR equivalent of 1.15 ± 0.15). On univariate analysis, presentation age, foveal retinoblastoma (at initial examination), use of TTT, and tumor-foveola distance (at last visit) were found to be significant risk factors for worse VA (P < .026). On multivariate analysis, however, only TTT was found to be significant (P = .010). At last visit, 6 of 27 (22%) patients had nystagmus and 12 of 20 (60%) bilaterally salvaged patients had strabismus (n = 10 exotropia and n = 2 esotropia). CONCLUSIONS: After multimodality treatments initiated with IVC, 50% of salvaged Group D retinoblastoma eyes had <20/200 vision, with TTT being a risk factor for worse vision; 60% had strabismus; and 22% had nystagmus
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