Arbuscular mycorrhizal fungi are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree at Pb addition levels of 0, 500, 1000 and 2000 mg kg-1 soil. AMF symbiosis (...) decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase, ascorbate peroxidases and glutathione peroxidase were enhanced, and hydrogen peroxide and malondialdehyde contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb contaminated soils. (shrink)

During the evolution of aerobic life, antioxidant defence systems developed that either directly prevent oxidative modifications of the cellular constituents or remove the modified components. An example of the latter is the proteasome, which removes cytosolic oxidised proteins. Recently, a novel mechanism of activation of the nuclear 20S proteasome was discovered: automodified poly‐(ADP‐ribose) polymerase‐1 (PARP‐1) activates the proteasome to facilitate selective degradation of oxidatively damaged histones. Since activation of the PARP‐1 itself is induced by DNA damage and is supposed (...) to play a role in DNA repair, these new results suggest a joint role of PARP‐1 in the removal of oxidised nucleoproteins and in DNA repair. We hypothesise that PARP‐1 could provide a co‐ordinative link between two nuclear antioxidant defence systems, whose concerted activation would produce a fast and efficient restoration of the native chromatin structure following oxidative stress. BioEssays 24:1060–1065, 2002. © 2002 Wiley‐Periodicals, Inc. (shrink)

Ascorbic acid is a redox regulator in many physiological processes. Besides its antioxidant activity, many intriguing functions of ascorbic acid in the expression of immunoregulatory genes have been suggested. Ascorbic acid acts as a co‐factor for the Fe+2‐containing α‐ketoglutarate‐dependent Jumonji‐C domain‐containing histone demethylases (JHDM) and Ten eleven translocation (TET) methylcytosine dioxygenasemediated epigenetic modulation. By influencing JHDM and TET, ascorbic acid facilitates the differentiation of double negative (CD4−CD8−) T cells to double positive (CD4+CD8+) T cells and of T‐helper cells (...) to different effector subsets. Ascorbic acid modulates plasma cell differentiation and promotes early differentiation of hematopoietic stem cells (HSCs) to NK cells. These findings indicate that ascorbic acid plays a significant role in regulating both innate and adaptive immune cells, opening up new research areas in Immunonutrition. Being a water‐soluble vitamin and a safe micro‐nutrient, ascorbic acid can be used as an adjunct therapy for many disorders of the immune system. (shrink)

Akt, a protein kinase hyperactivated in many tumors, plays a major role in both cell survival and resistance to tumor therapy. A recent study,1 along with other evidences, shows interestingly, that Akt is not a single‐function kinase, but may facilitate rather than inhibit cell death under certain conditions. This hitherto undetected function of Akt is accomplished by its ability to increase reactive oxygen species and to suppress antioxidant enzymes. The ability of Akt to down‐regulate antioxidant defenses uncovers a (...) novel Achilles' heel, which could be exploited by oxidant therapies in order to selectively eradicate tumor cells that express high levels of Akt activity. (shrink)

No overarching hypotheses tie the basic mechanisms of mitochondrial reactive oxygen species (ROS) production to activity dependent synapse pruning—a fundamental biological process in health and disease. Neuronal activity divergently regulates mitochondrial ROS: activity decreases whereas inactivity increases their production, respectively. Placing mitochondrial ROS as innate synaptic activity sentinels informs the novel hypothesis that: (1) at an inactive synapse, increased mitochondrial ROS production initiates intrinsic apoptosis dependent pruning; and (2) at an active synapse, decreased mitochondrial ROS production (...) masks intrinsic apoptosis dependent pruning. Immature antioxidant defense may enable the developing brain to harness mitochondrial ROS to prune weak synapses. Beyond development, endogenous antioxidant defense constrains mitochondrial (ROS) to mask pruning. Unwanted age‐related synapse loss may arise when mitochondrial ROS aberrantly recapitulate developmental pruning. Placing mitochondrial ROS with their hands on the shears is beneficial in early but deleterious in later life. (shrink)

The respiration of oxygen, while essential to aerobic organisms for the generation of energy, leads to the formation of reactive oxygen intermediates (ROIs) as harmful byproducts. ROIs damage nucleic acids, lipids and proteins. Therefore, protective mechanisms against elevated intracellular ROI levels, referred to as oxidative stress, have evolved. These include the activation of transcription factors which elevate the expression of protective enzymes. Eukaryotic cells have also evolved the ability to specifically generate ROIs are used as second messengers to activate gene (...) expression. Here we will discuss both prokaryotic and eukaryotic transcription factors that respond to ROIs. In addition, transcription factors will be described that are activated by either exposure to antioxidants, which reduce the intracellular ROI concentration, or by hypoxia, the absence of oxygen. (shrink)

Caffeine, a known CNS stimulant is given as an adjunct component in most abused drugs which could be fatal with repeated administration in many circumstances. This paper presents a study to investigate the effect of repeated administration of caffeine at high dose on rat liver, and discusses ethical and policy issues of caffeine use. Long Evans rats were treated with pure caffeine solution in distilled water through intragastric route once daily for consecutive 56 days. Three groups of rats recognized as (...) low dose, high dose and control group received 6mg caffeine / kg BW, 12mg caffeine / kg BW and distilled water, respectively. Rat plasma was examined for liver transaminases and alkaline phosphatases concentrations which were significantly increased in plasma as compared to the control. Both rat plasma and liver homogenate were subjected to estimate malondialdehyde, advanced oxidation protein product, nitric oxide, antioxidant enzyme catalase, glutathione and superoxide dismutase activity. MDA, AOPP, NO levels increased and SOD activity decreased significantly in both plasma and liver as compared to those of control where as CAT and GSH activity remain unchanged. Rat liver tissues were studied histochemically with Hematoxylin and Eosin, and Picro Sirius Red staining. Significantly increased infiltration of inflammatory cells and progressive deposition of collagen fibre were visible in liver tissue of caffeine treated both dose groups as compared to the control. Long term administration of caffeine at higher dose, significantly contributes to liver inflammation and consequent fibrogenesis. This raises significant ethical and policy issues. (shrink)

The North American wood frog, Rana sylvatica, endures seasonal whole‐body freezing during the winter and thawing during the spring without sustaining any apparent damage from ice or oxidative stress. Strategies from these frogs may solve the shortage of human donor organs, which is a multidisciplinary problem that can be alleviated by eliminating geographical boundaries. Rana sylvatica deploys an array of molecular and physiological responses, such as glucose production and microRNA regulation, to help it survive the cold. These strategies have been (...) adapted in the lab to impart cryotolerance in liver cells, and the non‐freezing supercooled storage of transplantable rat livers − milestones that have advanced the field toward cryopreserving human donor organs in the clinic. In this review, a case is presented for the use of non‐coding RNAs to decrease oxidative damage of donor organs by activating endogenous antioxidant systems prior to procurement. (shrink)

For this volume David Wiggins has selected and revised eleven of his essays in an area of metaphysics where his work has been particularly influential, and he has added a substantial introduction and one new unpublished essay. Among the subjects treated are substance, identity, persistence, persons, sortals, and artefacts.

use and tool making underlying a system of production mediating between needs and their satisfaction. – The relationship of the entire community to the ...

The academy is in a mess. The cultural theorist Bill Readings claimed that it is in ruins, while the political scientist Michael Oakeshott suggested that it has all but ceased to exist. At the very least, we might argue that the current financial squeeze has distorted the University into a shape that would be all but unrecognizable to Oakeshott and others writing in the 1950s and 1960s. I will begin this paper by tracing the development of the modern Enlightenment University (...) over the past 200 years from its roots in late 18th century Berlin to its current predicament. I will then turn my attention to the introduction during the 1990s of nursing education into the University, and examine the particular difficulties and tensions encountered at the interface between a professional practice and an academic discipline. Finally, I will propose philosophy as a way of dwelling in the ruins of the Enlightenment University and of reconciling the corporate demands of the University with the obligations of the nursing profession. (shrink)

Contemporary literature in philosophy of action seems to be divided overthe place of action in the natural causal world. I think that a disagreementabout ontology underlies the division. I argue here that human action isproperly understood only by reference to a category of process or activity,where this is not a category of particulars.

IntroductionDuring the COVID-19 outbreak, many citizens were asked to stay at home in self-quarantine, which can pose a significant challenge with respect to remaining physically active and maintaining mental health. This study aimed to evaluate the prevalence of inadequate physical activity, anxiety, and depression and to explore the relationship of physical activity with anxiety and depression symptoms among Chinese college students during quarantine.MethodUsing a web-based cross-sectional survey, we collected data from 1,396 Chinese college students. Anxiety and depression were (...) assessed with the Self-Rating Anxiety Scale and the Self-Rating Depression Scale, respectively. The data on physical activity were collected by types of physical activity and the International Physical Activity Questionnaire.ResultsDuring the COVID-19 outbreak, about 52.3% of Chinese college students had inadequate physical activity. The rates of anxiety and depression symptoms were 31.0 and 41.8%, respectively. A high level of physical activity was significantly closely associated with low anxiety, while a moderate, or high level of physical activity was significantly closely associated with reduced depression after adjusting confounding demographic factors. Moreover, specific types of physical activity, such as stretching and resistance training, were negatively correlated with both anxiety and depression; doing household chores was negatively correlated with depression.ConclusionOur findings highlight specific levels and types of home-based physical activities that need to be taken into consideration to protect the mental health of college students during the COVID-19 epidemic. (shrink)

In the Metaphysical Foundations of Natural Science, Kant claims that perception of force through touch is fundamental to our knowledge of substance in space. However, he also holds that perception cannot have modal content. Causation is a modal notion, so how can Kant allow perception of causal force? In response to this puzzle, I provide a new reading of Kant’s theory of touch. Touch does not involve perception of the necessity of a cause, but it does involve awareness of the (...) activity of our body in relation to other bodies. Human embodied activity has a hitherto unrecognized central role in Kant’s accounts of empirical cognition of substance in space, the science of such a substance, and the irreducibility of its causal forces. (shrink)

In essence firms or companies are usually thought to exist to make products for or provide services of some sort to third parties, other companies or individuals. The philosophical question which naturally arises then is ‘to the benefit of whom should a firm’s activities be aimed?’ Possible answers include the owners of the firm, the firm’s employees or wider society, the firm’s local community or their host nation. It is because of firms’ location within a wider society that the issue (...) of corporate social responsibility arises. The issue is do they contribute in a positive way to the fabric of society. In this paper we conduct an exploratory investigation whose research questions, broadly, are whether there is public evidence of corporate social responsibility activity by firms listed in the UK and to what extent, if any, such activities may amount to genuinely socially responsible management by the firms. We examined the most up to date annual reports of a split sample of 36 firms listed in the FTSE 350. The short answers to the two research questions above are: to some degree and no by some margin, based on data from the sample firms. (shrink)

Research on corporate political activity has considered a number of antecedents to a firm’s engagement in politics. The majority of this research has focused on either industry or firm-level motivations that lead to corporate political activity, leaving the role of the firm’s leader noticeably absent in such scholarship. This article combines ideas from Upper Echelons Theory with research in corporate political activity to bridge this important gap. More specifically, this research utilizes CEO demographic characteristics to determine whether (...) a firm will invest in political activity and how these characteristics influence the particular approach to political activity the firm undertakes. Considering 27 years of data from large U.S. firms, we find that a CEO’s age, tenure, functional, and educational backgrounds influence whether and how the firm invests in political activity. (shrink)

Experiments in animal models have shown that running increases neuronal activity in early visual areas in light as well as in darkness. This suggests that visual processing is influenced by locomotion independent of visual input. Combining mobile electroencephalography, motion- and eye-tracking, we investigated the influence of overground free walking on cortical alpha activity and eye movements in healthy humans. Alpha activity has been considered a valuable marker of inhibition of sensory processing and shown to negatively correlate with (...) neuronal firing rates. We found that walking led to a decrease in alpha activity over occipital cortex compared to standing. This decrease was present during walking in darkness as well as during light. Importantly, eye movements could not explain the change in alpha activity. Nevertheless, we found that walking and eye related movements were linked. While the blink rate increased with increasing walking speed independent of light or darkness, saccade rate was only significantly linked to walking speed in the light. Pupil size, on the other hand, was larger during darkness than during light, but only showed a modulation by walking in darkness. Analyzing the effect of walking with respect to the stride cycle, we further found that blinks and saccades preferentially occurred during the double support phase of walking. Alpha power, as shown previously, was lower during the swing phase than during the double support phase. We however could exclude the possibility that the alpha modulation was introduced by a walking movement induced change in electrode impedance. Overall, our work indicates that the human visual system is influenced by the current locomotion state of the body. This influence affects eye movement pattern as well as neuronal activity in sensory areas and might form part of an implicit strategy to optimally extract sensory information during locomotion. (shrink)

Then you have a look around, and see that none of the uninitiated are listening to us—I mean the people who think that nothing exists but what they can grasp with both hands; people who refuse to admit that actions and processes and the invisible world in general have any place in reality.

Talk of powers is muddled. Building upon Powers and capacities in philosophy: The new aristotelianism, Routledge, London, 2012a, pp 207–227), I disambiguate four senses of the term: powers construed as activity, as capacity/potentiality, as essence and as necessity, respectively, in an attempt to clarify what it is that realists about causal powers take themselves to be realists about.

Experimental philosophers have empirically challenged the connection between intuition and philosophical expertise. This paper reviews these challenges alongside other research findings in cognitive science on expert performance and argues for three claims. First, evidence taken to challenge philosophical expertise may also be explained by the well-researched failures and limitations of genuine expertise. Second, studying the failures and limitations of experts across many fields provides a promising research program upon which to base a new model of philosophical expertise. Third, a model (...) of philosophical expertise based on the limitations of genuine experts may suggest a series of constraints on the reliability of professional philosophical intuition. Even when the experts all agree, they may well be mistaken. — Bertrand Russell, On the Value of Scepticism. (shrink)

Empathy is the combined ability to interpret the emotional states of others and experience resultant, related emotions. The relation between prefrontal electroencephalographic asymmetry and emotion in children is well known. The association between positive emotion (assessed via parent report), empathy (measured via observation), and second-by-second brain electrical activity (recorded during a pleasurable task) was investigated using a sample of one hundred twenty-eight 6- to 10-year-old children. Contentment related to increasing left frontopolar activation (p < .05). Empathic concern and positive (...) empathy related to increasing right frontopolar activation (ps < .05). A second form of positive empathy related to increasing left dorsolateral activation (p < .05). This suggests that positive affect and (negative and positive) empathy both relate to changes in prefrontal activity during a pleasurable task. (shrink)

Activity theory is an interdisciplinary approach to human sciences that originates in the cultural-historical psychology school, initiated by Vygotsky, Leont'ev, and Luria. It takes the object-oriented, artifact-mediated collective activity system as its unit of analysis, thus bridging the gulf between the individual subject and the societal structure. This volume is the first comprehensive presentation of contemporary work in activity theory, with 26 original chapters by authors from ten countries. In Part I of the book, central theoretical issues (...) are discussed from different points of view. Some topics addressed in this part are epistemology, methodology, and the relationship between biological and cultural factors. Part II is devoted to the acquisition and development of language - a theme that played a central role in the work of Vygotsky and Luria. This part includes a chapter that analyzes writing activity in Japanese classrooms, and an original case study of literacy skills of a man with cerebral palsy. Part III contains chapters on play, learning, and education, and part IV addresses the meaning of new technology and the development of work activities. The final part covers issues of therapy and addiction. (shrink)

This chapter takes a fresh look at 3d2 of Spinoza’s Ethics, an absolutely pivotal definition for the ethical theory that ensues. According to it, “we act when something happens, in us or outside us, of which we are the adequate cause,” whereas we are passive “when something happens in us, or something follows from our nature, of which we are only a partial cause.” The definition of activity has puzzled scholars: how can we be an adequate, i.e. complete, cause (...) of an effect outside us (which clearly involves other causal factors as well)? However, the definition of passivity is hardly unproblematic either: how can something follow from the patient’s nature so that the patient can nevertheless be considered only a partial cause? I begin by outlining 3d2 and situating it in the historical context formed by Descartes, Hobbes, and the Aristotelian tradition. Then I show that the existing interpretations do not solve the problem of activity and argue that unraveling the problem requires taking properly into account the distinction between immanent and transeunt causality. In relation to the definition of passivity, I argue that Spinoza’s geometry-inspired theory of essence constitution offers the key to understanding the nature of passions. (shrink)

This paper reconstructs and analyzes Thomas Aquinas’ intriguing views on transeunt causal activity, which have been the subject of an interpretive debate spanning from the fifteenth century up until the present. In his Physics commentary, Aquinas defends the Aristotelian positions that the actualization of an agent’s active potential is the motion that it causes in its patient and action and passion are the same motion. Yet, in other texts, Aquinas claims that action differs from passion and “action is in (...) the agent” as subject. This paper proposes a solution for how to reconcile Aquinas’ varying claims about what transeunt causal activity is in reality. In addition to advancing understanding of Aquinas’ views on causal activity, the paper also offers insights into more general topics in his thought, such as the relationship between actualities and accidents and the nature of extrinsic accidents. (shrink)

Objective: The aim of this research was to study the mediation of body dissatisfaction, physical self-concept, and body mass index (BMI) on the relationship between physical activity and self-concept in adolescents. Materials and Methods: A sample of 652 Spanish students between 12 and 17 years participated in a cross-sectional study. Physical self-concept and general self-concept were assessed with the Physical Self-Concept Questionnaire (CAF), body dissatisfaction with the Body Shape Questionnaire (BSQ), and physical activity was estimated with the International (...) Physical Activity Questionnaire (IPAQ-SF). BMI was utilized as a measurement of body composition. Structural equation modeling was used to assess the results. Results: The resulting models showed good fit indexes. Physical activity had a positive and indirect effect on self-concept (β = 0.29, p < 0.01) and direct effects on dissatisfaction (β = -0.26, p < 0.01) and physical self-concept (β = 0.20, p < 0.01). BMI had a direct effect on dissatisfaction (β = 0.31, p < 0.01) and on physical self-concept (β = -0.10, p < 0.01) and an indirect effect on general self-concept (β = -0.24, p < 0.01). However, it was only associated with physical activity in males, playing a mediating role between physical activity and body dissatisfaction. Conclusion: Physical activity can help individuals to achieve a positive self-concept and promote psychological well-being in adolescents through the improvement of physical perceptions and body satisfaction. The importance of BMI, body dissatisfaction, and physical self-concept on the configuration of the self-concept are also emphasized. Educational policymakers and Physical Education teachers should implement strategies to promote physical activity in the schools and provide a Quality Physical Education programs to increase physical activity during adolescence. (shrink)

Nowadays, aesthetics are generally considered as a crucial aspect that affects the way we confront things, events, and states of affairs. However, the functional role of aesthetics in the interaction between agent and environment has not been addressed effectively. Our objective here is to provide an explanation concerning the role of aesthetics, and especially, of the aesthetic experience as a fundamental bodily and emotional activity in the respective interactions. An explanation of the functional role of the aesthetic experience could (...) offer new orientations to our understanding of embodied cognition and of aesthetics as a fundamental part of it. We argue that aesthetic experience, especially its emotional dimension, is an evaluative process that influences the anticipation for stable and successful interactions with the environment. In other words, aesthetics facilitates sense-making as they affect what might be anticipated by an action tendency with respect to an environment. (shrink)