A framework for interpolating scattered data using space-filling curves

The analysis of spatial data occurs in many disciplines and covers a wide variety activities. Available techniques for such analysis include spatial interpolation which is useful for tasks such as visualization and imputation. This paper proposes a novel approach to interpolation using space-filling curves. Two simple interpolation methods are described and their ability to interpolate is compared to several interpolation techniques including natural neighbour interpolation. The proposed approach requires a Monte-Carlo step that requires a large number of iterations. However experiments demonstrate that the number of iterations will not change appreciably with larger datasets

Parameter identification problems in the modelling of cell motility

We present a novel parameter identification algorithm for the estimation of parameters in models of cell motility using imaging data of migrating cells. Two alternative formulations of the objective functional that measures the difference between the computed and observed data are proposed and the parameter identification problem is formulated as a minimisation problem of nonlinear least squares type. A Levenberg–Marquardt based optimisation method is applied to the solution of the minimisation problem and the details of the implementation are discussed. A number of numerical experiments are presented which illustrate the robustness of the algorithm to parameter identification in the presence of large deformations and noisy data and parameter identification in three dimensional models of cell motility. An application to experimental data is also presented in which we seek to identify parameters in a model for the monopolar growth of fission yeast cells using experimental imaging data. Our numerical tests allow us to compare the method with the two different formulations of the objective functional and we conclude that the results with both objective functionals seem to agree

Overexpression of α(1,3)-fucosyltransferase VII is sufficient for the acquisition of lung colonization phenotype in human lung adenocarcinoma HAL-24Luc cells

Metastatic human lung adenocarcinoma HAL-8Luc cells display an enhanced expression of alpha(1,3)-fucosyltransferases (alpha(1,3)-Fuc-Ts) compared with their non-metastatic counterpart HAL-24Luc cells. This correlates with an increased surface expression of Lewis(x) (Le(x))- and Lewis(a) (Le(a))-related molecules and an in vitro enhanced adhesive capacity to E-selectin-expressing endothelial cells (Martin-Satué et al (1998). Cancer Res 58: 1544-1550). In the present work we have stably transfected HAL-24Luc cells with the cDNAs for the alpha(1,3)-Fuc-TIV and VII enzymes and analysed by flow cytometry the expression of Le(x), sialyl-Le(x), sialyl-Le(x) dimeric, Le(a) and sialyl-Le(a). Fuc-TVII transfectants exclusively overexpress sialyl-Le(x) while Fuc-TIV-transfected cells only overexpress the Le(x) oligosaccharide. We show that solely Fuc-TVII transfectants are able to adhere to interleukin-1beta-stimulated HUVEC monolayers. We also demonstrate that Fuc-TVII overexpression in HAL-24Luc cells is sufficient for the acquisition of the lung colonization phenotype. This is the first report directly showing the contribution of an alpha(1,3)-Fuc-T to the metastatic behaviour of human lung adenocarcinoma cells

The clinical significance of incidental intra-abdominal findings on positron emission tomography performed to investigate pulmonary nodules

<p>Abstract</p> <p>Background</p> <p>Lung cancer is a common cause of cancer-related death. Staging typically includes positron emission tomography (PET) scanning, in which¹⁸F-fluoro-2-dexoy-D-glucose (FDG) is taken up by cells proportional to metabolic activity, thus aiding in differentiating benign and malignant pulmonary nodules. Uptake of FDG can also occur in the abdomen. The clinical significance of incidental intraabdominal FDG uptake in the setting of pulmonary nodules is not well established. Our objective was to report on the clinical significance of incidental intra-abdominal FDG activity in the setting of lung cancer.</p> <p>Methods</p> <p>Fifteen hundred FDG-PET reports for studies performed for lung cancer were retrospectively reviewed for the presence of incidental FDG-positive intraabdominal findings. Patient charts with positive findings were then reviewed and information extracted.</p> <p>Results</p> <p>Twenty-five patients (25/1500) demonstrated incidental intraabdominal FDG uptake thought to be significant (1.7%) with a mean patient age of 71 years. Colonic uptake was most common (n = 17) with 9 (52%) being investigated further. Of these 9 cases, a diagnosis of malignancy was made in 3 patients, pre-malignant adenomas in 2 patients, a benign lipoma in 1 patient and no abnormal findings in the remaining patients. 8 patients were not investigated further (3 diagnosed with metastatic lung cancer and 2 were of advanced age) secondary to poor prognosis.</p> <p>Conclusion</p> <p>Incidental abdominal findings in the colon on FDG-PET scan for work-up of pulmonary nodules need to be further investigated by colonoscopy.</p

Validating MOSPA questionnaire for measuring physical activity in Pakistani women

BACKGROUND: Precise measurements of activity at a population level are important for monitoring trends and evaluating health promotion strategies. Few studies have assessed the measurement of physical activity in developing countries. The aim of this study was to validate the MOSPA (Monica Optional Study of Physical Activity) questionnaire which was developed for the WHO-Monitoring trends and determinants of cardiovasculr disease (MONICA) study sites. METHODS: The MOSPA questionnaire assesses energy expendtiture (EE) related to physical activity (employment, household work, transportation, and leisure time) over a one year period. This questionnaire has been described in the manuscript as the long term (LT) questionnaire. An adapted short term (ST) 5 day questionnaire was developed to assess convergent validity. Questionnaire data were compared with physical activity EE estimates from a Caltrac accelerometer and with body composition measures (height, weight and bioelectrical impedance) in 50 women from the Aga Khan University (AKU) hospital antenatal clinics, Pakistan. Other forms of EE i.e. resting EE and thermic effect of food were not assessd in this study. RESULTS: Subjects were aged 26 ± 3.8 years and were 16.1 ± 6.7 weeks pregnant. Their average weight was 58.8 ± 10.7 Kg. The average EE/day assessed by the Caltrac accelerometer, was 224 kcal and by MOSPA LT questionnaire it was 404 kcal. The questionnaires and Caltrac data were reasonably well correlated: r = 0.51 and r = 0.60 (P < 0.01) for LT and ST questionnaires respectively. Energy expenditure from questionnaire data was not correlated with body composition measures. CONCLUSION: The MOSPA questionnaire is useful in assessing physical activity levels in a sedentary population over a one year period

Testing foundations of quantum mechanics with photons

The foundational ideas of quantum mechanics continue to give rise to counterintuitive theories and physical effects that are in conflict with a classical description of Nature. Experiments with light at the single photon level have historically been at the forefront of tests of fundamental quantum theory and new developments in photonics engineering continue to enable new experiments. Here we review recent photonic experiments to test two foundational themes in quantum mechanics: wave-particle duality, central to recent complementarity and delayed-choice experiments; and Bell nonlocality where recent theoretical and technological advances have allowed all controversial loopholes to be separately addressed in different photonics experiments.Comment: 10 pages, 5 figures, published as a Nature Physics Insight review articl

Temperature differences are associated with malignancy on lung lesions: a clinical study

BACKGROUND: Although new endoscopic techniques can enhance the ability to detect a suspicious lung lesion, the primary diagnosis still depends on subjective visual assessment. We evaluated whether thermal heterogeneity of solid tumors, in bronchial epithelium, constitutes an additional marker for the diagnosis of benign and malignant lesions. METHODS: A new method, developed in our institute, is introduced in order to detect temperature in human pulmonary epithelium, in vivo. This method is based on a thermography catheter, which passes the biopsy channel of the fiber optic bronchoscope. We calculated the temperature differences (ΔT) between the lesion and a normal bronchial epithelium area on 22 lesions of 20 subjects, 50 – 65 years old. RESULTS: Eleven lesions were benign and 11 were malignant, according to the biopsy histology followed the thermography procedure. We found significant differences of ÄT between patients with benign and malignant tumor (0.71 ± 0.6 vs. 1.23 ± 0.4°C, p < 0.05). Logistic regression analysis showed that 1-Celsius degree differences between normal tissue and suspicious lesion six-fold the probability of malignancy (odds ratio = 6.18, 95% CI 0.89 – 42.7). Also, ΔT values greater than 1.05°C, constitutes a crucial point for the discrimination of malignancy, in bronchial epithelium, with sensitivity (64%) and specificity (91%). CONCLUSION: These findings suggest that the calculated ΔT between normal tissue and a neoplastic area could be a useful criterion for the diagnosis of malignancy in tumors of lung lesions

Unsupervised Analysis of Classical Biomedical Markers: Robustness and Medical Relevance of Patient Clustering Using Bioinformatics Tools

Motivation: It has been proposed that clustering clinical markers, such as blood test results, can be used to stratify patients. However, the robustness of clusters formed with this approach to data pre-processing and clustering algorithm choices has not been evaluated, nor has clustering reproducibility. Here, we made use of the NHANES survey to compare clusters generated with various combinations of pre-processing and clustering algorithms, and tested their reproducibility in two separate samples. Method: Values of 44 biomarkers and 19 health/life style traits were extracted from the National Health and Nutrition Examination Survey (NHANES). The 1999–2002 survey was used for training, while data from the 2003–2006 survey was tested as a validation set. Twelve combinations of pre-processing and clustering algorithms were applied to the training set. The quality of the resulting clusters was evaluated both by considering their properties and by comparative enrichment analysis. Cluster assignments were projected to the validation set (using an artificial neural network) and enrichment in health/life style traits in the resulting clusters was compared to the clusters generated from the original training set. Results: The clusters obtained with different pre-processing and clustering combinations differed both in terms of cluster quality measures and in terms of reproducibility of enrichment with health/life style properties. Z-score normalization, for example, dramatically improved cluster quality and enrichments, as compared to unprocessed data, regardless of the clustering algorithm used. Clustering diabetes patients revealed a group of patients enriched with retinopathies. This coul

Surgical reconstruction of the left main coronary artery with patch-angioplasty

<p>Abstract</p> <p>Background</p> <p>Conventional coronary artery bypass grafting (CABG) has been established as the treatment of choice for left main coronary artery (LMCA) stenosis However, the conventional grafting provides a retrograde perfusion to extensive myocardial area and leads prospectively to competitive flow of the non-occluded coronaries thus consuming the grafts. Surgical reconstruction of the LMCA with patch-angioplasty is an alternative method that eliminates these drawbacks.</p> <p>Methods</p> <p>Between February 1997 and July 2007, 37 patients with isolated LMCA stenosis were referred for surgical ostial reconstruction. In 27 patients (73%) surgical angioplasties have been performed. All patients were followed up clinically and with transesophageal echocardiography (TEE) and coronary angiography when required.</p> <p>Results</p> <p>In 10 patients (27%) a LMCA stenosis could not be confirmed. There were no early mortality or perioperative myocardial infarctions. The postoperative course was uneventful in all patients. In 25 patients, TEE demonstrated a wide open main stem flow pattern one to six months after reconstruction of the left main coronary artery with one patch mild aneurysmal dilated.</p> <p>Conclusions</p> <p>The surgical reconstruction with patch-angioplasty is a safe and effective method for the treatment of proximal and middle LMCA stenosis. Almost one third of the study group had no really LMCA stenosis: antegrade flow pattern remained sustained and the arterial grafts have been spared. In the cases of unclear or suspected LMCA stenosis, cardio-CT can be performed to unmask catheter-induced coronary spasm as the underlying reason for isolated LMCA stenosis.</p