A Sheaf-Theoretic Construction of Shape Space

We present a sheaf-theoretic construction of shape space -- the space of all shapes. We do this by describing a homotopy sheaf on the poset category of constructible sets, where each set is mapped to its Persistent Homology Transform (PHT). Recent results that build on fundamental work of Schapira have shown that this transform is injective, thus making the PHT a good summary object for each shape. Our homotopy sheaf result allows us to "glue" PHTs of different shapes together to build up the PHT of a larger shape. In the case where our shape is a polyhedron we prove a generalized nerve lemma for the PHT. Finally, by re-examining the sampling result of Smale-Niyogi-Weinberger, we show that we can reliably approximate the PHT of a manifold by a polyhedron up to arbitrary precision.Comment: 17 pages, 6 figure

Abnormality Detection in ECG Signal applying Poincare and Entropy-based Approaches

Detection of abnormality in heart is of major importance for early and appropriate clinical medication. In this work, we have proposed two models for detection of abnormality in ECG signals. The normal ECG signals are closely repetitive in nature to a large extent, whereas ECG signals with abnormalities tend to differ from cycle to cycle. Hence, repetitive plot like the Poincare is efficient to detect such non-repetitiveness of the signal; thereby, indicating abnormalities. Hence, we have used Poincare plot to develop the two proposed models. One of the models uses direct analysis of the binary image of the plot to detect the difference in retracing, between the healthy and unhealthy samples. The other model uses entropy of the Poincare plot to detect the difference in randomness of plots between the two classes. Most importantly, we have used only lead II ECG signal for analysis. This ensures ease of computation as it uses signal of only a single lead instead of the 12 leads of the complete ECG signal. We have validated the proposed models using ECG signals from the ‘ptb database’. We have observed that the entropy analysis of the Poincare plots gives the best results with 90% accuracy of abnormality detection. This high accuracy of classification, combined with less computational burden enables its practical implementation for the development of a real life abnormality detection schem

A study on adverse drug reactions to non-ionic contrast medium in an Indian population: a 1-year experience

Background: To the best of our understanding, very few studies focusing on the adverse drug reaction (ADR) profile of non-ionic contrast medium (NICM) has been carried out until date among the Indian population. Hence, this study was planned. We sincerely believe that the knowledge gathered from this study can improve safer usage of these agents among the patients of Indian origin. The objective was to evaluate the incidence and severity of ADRs of non-ionic radio contrast media (CM) used in tertiary care hospital in Eastern India.Methods: For the duration of 1-year from July 2011 to July 2012, we prospectively recorded all the ADRs associated with the administration of NICM (iohexol and ioversol) in 3708 patients of Indian origin undergoing computed tomography scan at the hospital. The average median age, weight, dose used; types of ADRs, concomitant medication, final diagnosis, reasons for use were recorded and analyzed with appropriate statistical tools. Causality assessment was performed using Naranjo scale.Results: Eleven of 3708 patients who received either ioversol or iohexol developed ADRs (i.e. 0.3% of patients). The most common ADR was rigor. The incidences of mild, moderate and severe reactions were 55%, 36% and 9%, respectively. Average median age, weight, and dose used were 35 years, 66 kg and 70 ml, respectively. All the ADRs were early (occurred within 1 hr of CM administration). Due to logical constraints, the follow-up of these patients was not possible and hence late ADRs were not captured. The common concomitant medication used was pantoprazole (63.63% of patients). The difference in the incidence of ADRs by age distribution (Group 1 - Iohexol, Group 2 - Ioversol) and weight distribution was not statistically significant (p=0.75 and p=0.18, respectively). Causality analysis revealed that all the ADRs were possible (Score of 4). Interestingly, the incidence of reactions was noted to be higher in patients with a history of gastro intestinal disorders (45.45%).Conclusions: This pilot study reveals that adverse reactions to NICM are rare and severe reactions are less common among the patients of Indian origin. However, a larger multicentric study across the country should be carried out to understand the safety profile of these CM better among the Indian population

Bioremediation: the eco-friendly solution to the hazardous problem of environmental pollution

Bioremediation is a technique to enhance natural biological processes to rectify polluted groundwater, soil, and even entire habitats. Bioremediation techniques use biological agents to act upon hazardous, toxic materials and subsequently convert them into less toxic substances.Microbes are organisms ubiquitously present in the biosphere. These microorganisms are the main agents that remediate toxic and polluted environmental conditions. Highly polluted areas can be rectified using proper bioremediation procedures and interventions. In this review we have studied the different bioremediation techniques which can be utilized to correct the harmful effects of environmental pollution. In this study we have also emphasized on the benefits of adopting bioremediation as an efficient alternative technique in comparison to the traditional physical and chemical methods to restore the healthy environmental conditions

Trauma from Occlusion: Practical Management Guidelines

Occlusal trauma is trauma to the periodontium from functional or parafunctional force’s causing damage to the teeth and its attachment apparatus by exceeding its adaptive and reparative capacities. Occlusal instability is a common cause for trauma from occlusion, resulting in numerous complications. It often leads to interference which reflexively shifts or slides the jaw forward on one or both the side to find a spot where most teeth come together. This action protects the teeth from injury caused by chewing on just one tooth. Overtime, this shift can cause a whole host of problems from TMJ pain, post restorative complications, headache, tooth sensitivity, recession, broken and loss of teeth and orofacial pain. These occlusal interferences and bite discrepancies are treatable with minimally invasive dentistry. Occlusal equilibration is a therapy that is used when the cause of trauma is due to occlusal instability. This involves the reshaping of the teeth where the improper biting surfaces are located. The key lies in decoding the cause, but often treatment is only directed towards the effects. Only a thorough evaluation and occlusal analysis will lead to a definitive diagnosis that will help in better anticipation of the damages