Towards a general theory for modelling qualitative space

Qualitative spatial representation and reasoning are techniques for modeling and manipulating objects and relationships in space. Finding ways for defining the complete and sound (physically plausible) set of relationships between spatial objects is a prerequisite for the development and realization of qualitative representation and reasoning formalisms. Establishing the set of sound relationships is a complicated task especially when complex objects are considered. Hence, current approaches to qualitative representation and reasoning are limited to handling simple spatial objects. In this paper, we introduce a constraint-based approach to qualitative representation of topological relationships by defining a set of general soundness rules. The rules reduce the combinatorial set of relations produced by the method to the complete and physically possible ones. The rules are general and apply to objects of arbitrary complexity and together with the representation and reasoning formalism form a theory for qualitative space

Copper oxide nanoparticles induce oxidative stress and cytotoxicity in airway epithelial cells

Metal oxide nanoparticles are often used as industrial catalysts and elevated levels of these particles have been clearly demonstrated at sites surrounding factories. To date, limited toxicity data on metal oxide nanoparticles are available. To understand the impact of these airborne pollutants on the respiratory system, airway epithelial (HEp-2) cells were exposed to increasing doses of silicon oxide (SiO2), ferric oxide (Fe2O3) and copper oxide (CuO) nanoparticles, the leading metal oxides found in ambient air surrounding factories. CuO induced the greatest amount of cytotoxicity in a dose-dependent manner; while even high doses (400 μg/cm2) of SiO2 and Fe2O3 were non-toxic to HEp-2 cells. Although all metal oxide nanoparticles were able to generate ROS in HEp-2 cells, CuO was better able to overwhelm antioxidant defenses (e.g. catalase and glutathione reductase). A significant increase in the level of 8-isoprostanes and in the ratio of GSSG to total glutathione in cells exposed to CuO suggested that ROS generated by CuO induced oxidative stress in HEp-2 cells. Co-treatment of cells with CuO and the antioxidant resveratrol increased cell viability suggesting that oxidative stress may be the cause of the cytotoxic effect of CuO. These studies demonstrated that there is a high degree of variability in the cytotoxic effects of metal oxides, that this variability is not due to the solubility of the transition metal, and that this variability appears to involve sustained oxidative stress possibly due to redox cycling. © 2009 Elsevier Ltd. All rights reserved

Order in space: a general formalism for spatial reasoning

In this paper we propose a general approach for reasoning in space. The approach is composed of a set of two general constraints to govern the spatial relationships between objects in space, and two rules to propagate relationships between those objects. The approach is based on a novel representation of the topology of the space as a connected set of components using a structure called adjacency matrix which can capture the topology of objects of different complexity in any space dimension. The formalism is used to explain spatial compositions resulting in indefinite and definite relations and it is shown to be applicable to reasoning in the temporal domain. The main contribution of the formalism is that it provides means for constructing composition tables for objects with arbitrary complexity in any space dimension. A new composition table between spatial objects of different types is presented. A major advantage of the method is that reasoning between objects of any complexity can be achieved in a defined limited number of steps. Hence, the incorporation of spatial reasoning mechanisms in spatial information systems becomes possible

Episodes in space: qualitative representation and reasoning over spatio-temporal objects

There is growing interest in many application domains for the temporal treatment and manipulation of spatially referenced objects. Handling the time dimension in spatial databases can greatly enhance and extend their functionality and usability by offering means of understanding the spatial behaviour in time. Few works, to date, have been directed towards the development of formalisms for representation and reasoning in this domain. In this paper, a new approach is presented for the representation and reasoning over spatio-temporal relationships. The approach is simple and aims to satisfy the requirements of coherency, expressiveness and reasoning power. Consistent behaviours of spatial objects in time are denoted episodes. The topology of the domain is defined by decomposing episodes into representative components and relationships are defined between those components. Spatio-temporal reasoning is achieved by composing the relationships between the object components using constraint networks. New composition tables between simple spatio-temporal regions and between regions and volumes are also derived and used in the reasoning process

SPARQS: a qualitative spatial reasoning engine

In this paper the design and implementation of a general qualitative spatial reasoning engine (SPARQS) is presented. Qualitative treatment of information in large spatial databases is used to complement the quantitative approaches to managing those systems, in particular, it is used for the automatic derivation of implicit spatial relationships and in maintaining the integrity of the database. To be of practical use, composition tables of spatial relationships between different types of objects need to be developed and integrated in those systems. The automatic derivation of such tables is considered to be a major challenge to current reasoning approaches. In this paper, this issue is addressed and a new approach to the automatic derivation of composition tables is presented. The method is founded on a sound set-theoretical approach for the representation and reasoning over arbitrarily shaped objects in space. A reasoning engine tool, SPARQS, has been implemented to demonstrate the validity of the approach. The engine is composed of a basic graphical interface where composition tables between the most common types of spatial objects are built. An advanced interface is also provided, where users are able to describe shapes of arbitrary complexity and to derive the composition of chosen spatial relationships. Examples of the application of the method using different objects and different types of spatial relationships are presented and new composition tables are built using the reasoning engine

In vitro and in vivo assessment of pulmonary risk associated with exposure to combustion generated fine particles

Strong correlations exist between exposure to PM2.5 and adverse pulmonary effects. PM2.5 consists of fine (≤2.5μm) and ultrafine (≤0.1μm) particles with ultrafine particles accounting for \u3e70% of the total particles. Environmentally persistent free radicals (EPFRs) have recently been identified in airborne PM2.5. To determine the adverse pulmonary effects of EPFRs associated with exposure to elevated levels of PM2.5, we engineered 2.5μm surrogate EPFR-particle systems. We demonstrated that EPFRs generated greater oxidative stress in vitro, which was partly responsible for the enhanced cytotoxicity following exposure. In vivo studies using rats exposed to EPFRs containing particles demonstrated minimal adverse pulmonary effects. Additional studies revealed that fine particles failed to reach the alveolar region. Overall, our study implies qualitative differences between the health effects of PM size fractions. © 2010 Elsevier B.V

The impact of social media in business growth and performance: A scientometrics analysis

The purpose of this research is to investigate the status and the evolution of the scientific studies on the applications of social media in the business. The present research is an applied scientific method based on quantitative approach by using library method and scientometrics indicators. With the use of bibliometric library of R software, scientific products in the field of social media applications in business from 2005 to the end of January 2019, the study overviews trends and achievements of this field. The results show that from the beginning of 2005 through January 2019, 2682 articles have been indexed in Web of Science in the field of social media and business; however, since 2009, scientific productions in this topic have grown rapidly and in 2017, there was a substantial increase in the number of studies. The findings also show that the United States with 1269 published articles and the Business Horizons Magazine with the publication of 73 articles, pioneered in the publications of this topic. Analyzing the content of the works produced in the applications of the social media and businesses can help us better understand the growth trend in this area

Echocardiographic Parameters of Severity in Isolated Neonatal Patent Ductus Arteriosus

Background: A hemodynamically-significant patent ductus arteriosus (hsPDA) compromises the early neonatal transition. There is no general agreement on echocardiographic indicators of hsPDA that can predict clinical decompensation. Aim of the Work: We aimed to assess echocardiographic parameters that are associated with the isolated PDA effects on hemodynamics, which could help in subsequent management decision making. Materials and Methods: We conducted a prospective observational analytical study on 50 neonates with isolated PDA and 20 controls. They underwent clinical and echocardiographic assessment at 48 hours of age, after another 48-72 hours and prior to discharge. Results: No correlation was found between PDA diameter and weight (p=0.72), length (p=0.11), Body surface area (BSA) (p=0.33), gestational age (p=0.13). A strong association of PDA-related hemodynamic instability was found with pulmonary hypertension (p=<0.01 & 0.05 for initial and latter studies). Left atrium diameter (LA) Z-score was higher among cases, correlated with PDA size in the 3 echocardiographic studies (p=0.001, 0.001 and 0.007 respectively), and correlated with hemodynamic instability in the initial study (p=0.03). Diameter of descending aorta at level of diaphragm and pulmonary flow/systemic flow ratio (Qp:Qs) correlated with PDA diameter in the latter 2 studies (p=0.001). Main pulmonary artery and left pulmonary artery (LPA) Z-scores were correlated with PDA size at the initial and follow-up studies as expected (p=0.001, 0.047 & 0.047; and p=0.004, 0.018 & 0.032, respectively). LPA Z-score correlated with hemodynamic instability at the follow-up study (p=0.005), which was not sustained at the subsequent study. Conclusion: Pulmonary hypertension, larger LA Z-score and LPA Z-scores are important early (at 48 hours) associations of a hsPDA and hemodynamic instability

Prevalence of Hepatitis C Virus Seropositivity and Its Impact on Coronary Artery Disease among Egyptian Patients Referred for Coronary Angiography

Background. We tested the prevalence and impact of HCV seropositivity among Egyptian patients referred for coronary angiography. Subjects and Methods. This cross-sectional study was conducted in Zagazig University hospitals including 509 patients scheduled for elective coronary angiography between June 2013 and June 2014. By taking full history on admission, laboratory workup including HCV Ab, echocardiography study, and coronary angiography, we calculated the mean number of coronary artery lesions and the mean number of affected coronary artery vessels for all patients. The severity of the coronary lesions was estimated using the Gensini score. Results. HCV seropositive patients referred for coronary angiography were about 30.3% (which is greater than the prevalence of HCV seropositivity among general population in Egypt), patients proved to have CAD who are HCV antibody positive had more severe coronary lesions than in seronegative one (p<0.05), and patients proved to have CAD who are HCV antibody positive had comparable prevalence of cardiovascular risk factors as seronegative patients except for diabetes and hypertension which are more prevalent in seronegative patients (p<0.05). Conclusion. Prevalence of HCV antibody positive patients referred for coronary angiography was about 30.3%, and CAD patients who are HCV antibody positive had more severe coronary lesions and less prevalence of diabetes and hypertension than HCV antibody negative