43 research outputs found
Helicity and spin conservation in Maxwell theory and Linearized Gravity
A duality symmetric formulation of linearized gravity has been introduced by Barnett and used to show the conservation of helicity. However, the relation between helicity and spin as well as the separate conservation of the spin and orbital parts of angular momentum, which is known to hold in Maxwell theory, was not considered. These conservation laws are known to follow from the conservation of the so-called helicity array, an analog of the zilch tensor, which includes helicity, spin, and spin-flux or infra-zilch. In the present paper we prove the conservation of spin and orbital angular momentum for linearized gravity on Minkowski space, and construct the analog of the helicity array for linearized gravity
Helicity, Spin, and Infra-zilch of Light: a Lorentz Covariant Formulation
The spin part of angular momentum of the electromagnetic field is known since the 1990's to be a separately conserved quantity. Cameron et al. introduced the helicity array, a non-covariant analog of Lipkin's zilch tensor, which expresses the hierarchy of conservation laws including helicity, spin, as well as the spin-flux or infra-zilch. In this paper, a novel conserved Lorentz covariant tensor, termed the helicity tensor, is introduced. The conservation laws arising from the helicity array can be obtained from the helicity tensor. The Lorentz covariance of the helicity tensor is in contrast to previous formulations of the helicity hierarchy of conservation laws, which required the non-Lorentz covariant transverse gauge. The helicity tensor is shown to arise as a Noether current for a variational symmetry of a duality-symmetric Lagrangian for Maxwell theory
Mitochondria:at the crossroads of regulating lung epithelial cell function in chronic obstructive pulmonary disease
Disturbances in mitochondrial structure and function in lung epithelial cells have been implicated in the pathogenesis of various lung diseases, including chronic obstructive pulmonary disease (COPD). Such disturbances affect not only cellular energy metabolism but also alter a range of indispensable cellular homeostatic functions in which mitochondria are known to be involved. These range from cellular differentiation, cell death pathways, and cellular remodeling to physical barrier function and innate immunity. all of which are known to be impacted by exposure to cigarette smoke and have been linked to COPD pathogenesis. Next to their well-established role as the first physical frontline against external insults, lung epithelial cells are immunologically active. Malfunctioning epithelial cells with defective mitochondria are unable to maintain homeostasis and respond adequately to further stress or injury, which may ultimately shape the phenotype of lung diseases. In this review, we provide a comprehensive overview of the impact of cigarette smoke on the development of mitochondrial dysfunction in the lung epithelium and highlight the consequences for cell function, innate immune responses, epithelial remodeling, and epithelial barrier function in COPD. We also discuss the applicability and potential therapeutic value of recently proposed strategies for the restoration of mitochondrial function in the treatment of COPD
Optimizing linear alkyl benzene sulfonate removal using fenton oxidation process in taguchi method
Linear alkyl benzene sulfonate (LAS), which is the most common used anionic surfactant in detergents manufacturing, can discharge onto water resources through wastewater and causes change in taste and odor, disruption in water treatment processes, aquatics death, and oxygen transfer limitation. Accordingly, this article investigates to optimize LAS removal using Fenton oxidation process in Taguchi Method for the first time. LAS removal using Fenton oxidation was perused experimentally in a lab-scale reactor
Airway Epithelial Barrier Dysfunction in Chronic Obstructive Pulmonary Disease:Role of Cigarette Smoke Exposure
The epithelial lining of the airway forms the first barrier against environmental insults, such as inhaled cigarette smoke, which is the primary risk factor for the development of chronic obstructive pulmonary disease (COPD). The barrier is formed by airway epithelial junctions, which are interconnected structures that restrict permeability to inhaled pathogens and environmental stressors. Destruction of the epithelial barrier not only exposes subepithelial layers to hazardous agents in the inspired air, but also alters the normal function of epithelial cells, which may eventually contribute to the development of COPD. Of note, disruption of epithelial junctions may lead to modulation of signaling pathways involved in differentiation, repair, and proinflammatory responses. Epithelial barrier dysfunction may be particularly relevant in COPD, where repeated injury by cigarette smoke exposure, pathogens, inflammatory mediators, and impaired epithelial regeneration may compromise the barrier function. In the current review, we discuss recent advances in understanding the mechanisms of barrier dysfunction in COPD, as well as the molecular mechanisms that underlie the impaired repair response of the injured epithelium in COPD and its inability to redifferentiate into a functionally intact epithelium
Fatty liver index vs waist circumference for predicting non-alcoholic fatty liver disease
AIM: To determine the discriminatory performance of fatty liver index (FLI) for non-alcoholic fatty liver disease (NAFLD). METHODS: The data of 5052 subjects aged over 18 years were analyzed. FLI was calculated from body mass index, waist circumference (WC), triglyceride, and gamma glutamyl transferase data. Logistic regression analysis was conducted to determine the association between FLI and NAFLD. The discriminatory performance of FLI in the diagnosis of NAFLD was evaluated by receiver operating characteristic analysis. Area under the curves (AUCs) and related confidence intervals were estimated. Optimal cutoff points of FLI in the diagnosis of NAFLD were determined based on the maximum values of Youden's index. RESULTS: The mean age of men and women in the study population were 44.8 ± 16.8 and 43.78 ± 15.43, respectively (P = 0.0216). The prevalence of NAFLD was 40.1 in men and 44.2 in women (P < 0.0017). FLI was strongly associated with NAFLD, so that even a one unit increase in FLI increased the chance of developing NAFLD by 5.8 (OR = 1.058, 95CI: 1.054-1.063, P < 0.0001). Although FLI showed good performance in the diagnosis of NAFLD (AUC = 0.8656 (95CI: 0.8548-0.8764), there was no significant difference with regards to WC (AUC = 0.8533, 95CI: 0.8419-0.8646). The performance of FLI was not significantly different between men (AUC = 0.8648, 95CI: 0.8505-0.8791) and women (AUC = 0.8682, 95CI: 0.8513-0.8851). The highest performance with regards to age was related to the 18-39 age group (AUC = 0.8930, 95CI: 0.8766-0.9093). The optimal cutoff points of FLI were 46.9 in men (sensitivity = 0.8242, specificity = 0.7687, Youden's index = 0.5929) and 53.8 in women (sensitivity = 0.8233, specificity = 0.7655, Youden's index = 0.5888). CONCLUSION: Although FLI had acceptable discriminatory power in the diagnosis of NAFLD, WC was a simpler and more accessible index with a similar performance. © 2016 Baishideng Publishing Group Inc. All rights reserved
The zilch electromagnetic conservation law revisited
It is shown that the zilch conservation law arises as the Noether current
corresponding to a variational symmetry of a duality-symmetric Maxwell
Lagrangian. The action of the corresponding symmetry generator on the
duality-symmetric Lagrangian, while non-vanishing, is a total divergence as
required by the Noether theory. The variational nature of the zilch
conservation law was previously known only for some of the components of the
zilch tensor, notably the optical chirality. By contrast, our analysis is fully
covariant and is therefore valid for all components of the zilch tensor. The
analysis is presented here for both real and complex versions of
duality-symmetric Maxwell Lagrangians.Comment: 15 pages, 1 table, no figure
"Begging the Question"-Does Toxocara Infection/Exposure Associate with Multiple Sclerosis-Risk?
Although the cause of multiple sclerosis (MS) is unclear, infectious agents, including some parasitic roundworms (nematodes), have been proposed as possible risk factors or contributors. Here, we conducted a systematic review and meta-analysis of published observational studies to evaluate whether there is a possible association between infection with, or exposure to, one or more members of the genus Toxocara (phylum Nematoda; superfamily Ascaridoidea) and MS. We undertook a search of public literature databases to identify relevant studies and then used a random-effects meta-analysis model to generate the pooled odds ratio (OR) and 95% confidence intervals (CIs). This search identified six of a total of 1371 articles that were relevant to the topic; these published studies involved totals of 473 MS patients and 647 control subjects. Anti-Toxocara IgG serum antibodies were detected in 62 MS patients and 37 controls, resulting in respective seroprevalences of 13.1% (95% CI: 8.2–20.3) and 4.8% (95% CI: 2.5–9.2), indicating an association (pooled OR, 3.01; 95% CI: 1.46–6.21). Because of the publication bias identified (six eligible studies), well-designed and -controlled studies are required in the future to rigorously test the hypothesis that Toxocara infection/exposure has an association with MS
Feasibility Removal of THMs Precursors using Al+3 and Fe+3Compounds from Shahrchay River in Urmia, Iran
Abstract
Introduction: Among disinfection by products, trihalomethanes (THMs) are known as the main carcinogen compounds that it’s the major precursor is humic compounds. The aim of this study was to investigate the removal of humic compounds using Al+3 and Fe+3 compounds from Shahrchay river water.in Urmia city.
Methods: This study was done experimental. Experiments perform in jar test batch reactor in different values of pH, Al+3 and Fe+3. Also THMs was measured under optimal removal conditions
Results: The optimal dosages of ferric chloride, alum and PACl for removal of humic compound obtained, 10, 30 and 20 mg/L, respectively. The highest removal efficiency was related ferric chloride with 89 %, and removal efficiency for PACl and alum were 88% and 81%. But SUVA (specific ultraviolet absorbance) index decreased less than USEPA permissible limits (less than L/mg m 2) only with ferric chloride.
Conclusion: Ferric chloride can be used for removal of humic acid in water of Urmia Shaharchi river to decreased SUVA index in permission ranges. But the use of aluminum salts may lead to THM formation. Chlorinated treated water with Ferric chloride, approved reduction of the amount of trihalomethanes to USEPA permissible limits (ppb <80
The Zilch Electromagnetic Conservation Law in Variational Characteristic Form
In this paper we consider the zilch conservation laws for Maxwell theory and demonstrate that in the duality-symmetric version of Maxwell theory, the zilch arises as a Noether current for a variational symmetry of the duality symmetric Lagrangian which we identify through an application of the reverse of the Noether theorem. A variational symmetry leaves Lagrangian invariant up to a total divergence, without restricting to solutions of the field equations. This fact was previously known only for the so-called chirality current, i.e. the -component of zilch