Theoretical study on behaviour of superplastic forming/diffusion bonding of bulk metallic glasses

Based on the behaviour of the superplastic deformation of metallic glasses and Pilling’s model, a diffusion bonding model suitable for metallic glasses is proposed in the present study. In the current model, the diffusion bonding processes consists of two stages: one is the plastic deformation stage and the other is the void shrinkage stage, in which, the atom diffusion and superplastic deformation are responsible for the void shrinkage. Applying this model to the diffusion bonding of a Zr based metallic glass, the predicted bonding time is in good agreement with the experimental result. A map for determining the bonding temperature and time to achieve high quality bonding in a Zr based metallic glass is suggested.

Immune-mediated mechanisms of parasite tissue sequestration during experimental cerebral malaria

Cerebral malaria is a severe complication of malaria. Sequestration of parasitized RBCs in brain microvasculature is associated with disease pathogenesis, but our understanding of this process is incomplete. In this study, we examined parasite tissue sequestration in an experimental model of cerebral malaria (ECM). We show that a rapid increase in parasite biomass is strongly associated with the induction of ECM, mediated by IFN-γ and lymphotoxin α, whereas TNF and IL-10 limit this process. Crucially, we discovered that host CD4+ and CD8+ T cells promote parasite accumulation in vital organs, including the brain. Modulation of CD4+ T cell responses by helminth coinfection amplified CD4+ T cell-mediated parasite sequestration, whereas vaccination could generate CD4+ T cells that reduced parasite biomass and prevented ECM. These findings provide novel insights into immune-mediated mechanisms of ECM pathogenesis and highlight the potential of T cells to both prevent and promote infectious diseases.

Mechanisms of nitric oxide-mediated neurogenic,vasodilation in mesenteric resistance arteries of toad, Bufo marinus

This study determined the role of nitric oxide (NO) in neurogenic vasodilation in mesenteric resistance arteries of the toad Bufo marinus. NO synthase (NOS) was anatomically demonstrated in perivascular nerves, but not in the endothelium. ACh and nicotine caused TTX-sensitive neurogenic vasodilation of mesenteric arteries. The ACh-induced vasodilation was endothelium-independent and was mediated by the NO/soluble guanylyl cyclase signaling pathway, inasmuch as the vasodilation was blocked by the soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one and the NOS inhibitors N^ω- nitro-L-arginine methyl ester and N^ω-nitro-L-arginine. Furthermore, the ACh-induced vasodilation was significantly decreased by the more selective neural NOS inhibitor N⁵-(1-imino-3-butenyl)-L-ornithine. The nicotine-induced vasodilation was endothelium-independent and mediated by NO and calcitonin gene-related peptide (CGRP), inasmuch as pretreatment of mesenteric arteries with a combination of N^ω-nitro-L-arginine and the CGRP receptor antagonist CGRP-(8–37) blocked the vasodilation. Clotrimazole significantly decreased the ACh-induced response, providing evidence that a component of the NO vasodilation involved Ca^2+-activated K⁺ or voltage-gated K⁺ channels. These data show that NO control of mesenteric resistance arteries of toad is provided by nitrergic nerves, rather than the endothelium, and implicate NO as a potentially important regulator of gut blood flow and peripheral blood pressure.

Molecular mechanisms of inflammation : anti-inflammatory benefits of virgin olive oil and the phenolic compound oleocanthal

Chronic inflammation is a critical factor in the pathogenesis of many inflammatory disease states including cardiovascular disease, cancer, diabetes, degenerative joint diseases and neurodegenerative diseases. Chronic inflammatory states are poorly understood, however it is known that dietary habits can evoke or attenuate inflammatory responses. Popular methods to deal with inflammation and its associated symptoms involve the use of non steroidal anti-inflammatory drugs, however the use of these drugs are associated with severe side effects. Therefore, investigations concerned with natural methods of inflammatory control are warranted. A traditional Mediterranean diet has been shown to confer some protection against the pathology of chronic diseases through the attenuation of proinflammatory mediators and this has been partially attributed to the high intake of virgin olive oil accompanying this dietary regime. Virgin olive oil contains numerous phenolic compounds that exert potent anti-inflammatory actions. Of interest to this paper is the recently discovered phenolic compound oleocanthal. Oleocanthal is contained in virgin olive oil and possesses similar anti-inflammatory properties to ibuprofen. This pharmacological similarity has provoked interest in oleocanthal and the few studies conducted thus far have verified its anti-inflammatory and potential therapeutic actions. A review of the health benefits of the Mediterranean diet and antiinflammatory properties of virgin olive oil is presented with the additional emphasis on the pharmacological and anti-inflammatory properties of the phenolic compound oleocanthal.

N-acetylcysteine in psychiatry - current therapeutic evidence and potential mechanisms of action

There is an expanding field of research investigating the benefits of alternatives to current pharmacological therapies in psychiatry. N-acetylcysteine (NAC) is emerging as a useful agent in the treatment of psychiatric disorders. Like many therapies, the clinical origins of NAC are far removed from its current use in psychiatry. Whereas the mechanisms of NAC are only beginning to be understood, it is likely that NAC is exerting benefits beyond being a precursor to the antioxidant, glutathione, modulating glutamatergic, neurotropic and inflammatory pathways. This review outlines the current literature regarding the use of NAC in disorders including addiction, compulsive and grooming disorders, schizophrenia and bipolar disorder. N-acetylcysteine has shown promising results in populations with these disorders, including those in whom treatment efficacy has previously been limited. The therapeutic potential of this acetylated amino acid is beginning to emerge in the field of psychiatric research.

Defence mechanisms of a resistant monocot model to phytophthora cinnamomi

The plant pathogen Phytophthora cinnamomi causes devastating disease in natural and agricultural systems worldwide. While some plants can survive, little is known about the underlying mechanisms of resistance. This research used histochemical and genome-wide analysis to identify key cellular and molecular defence mechanisms within the resistant plant Zea mays.

Identification and possible disease mechanisms of an under-recognized fungus, Aureobasidium pullulans

Background: Investigations into the occurrence and health effects of yeast-like fungi in the outdoor air in the US have been limited. We sought to identify a respirable-sized fungus common in the Pasadena air, locate a major source for the emissions and investigate its relevance to allergic disease. Methods: Yeast-like fungi sampled from the environment were isolated, microscopically examined and sequenced. Pasadena allergy patients were skin tested with commercially available fungal extracts. Patient serum was immunoanalyzed for specific IgE reactivity. Nearby vegetation was analyzed in a controlled emission chamber to find a major source for the aerosols. Results: Hyaline unicellular conidia comprised up to 90% (41,250 m^-3 of air) of total fungal counts and generally peaked at night and during periods of rainfall and ensuing winds throughout the fall and winter. Flowers were determined to be a major source of the emissions. The cellular and colonial morphology of isolates were consistent with Aureobasidium species. The sequence of the D1/D2 region of the 26S ribosomal subunit of isolates from flowers showed identity to two strains of Aureohasidium pullulans (black yeast). Seventeen percent (16/94) of atopic individuals had positive skin testing with A. pullulans extract. Patient sera gE identified several high molecular weight allergens in Aureobasidium extracts. Conclusions: Respirable-sized conidia of A. pullulans are emitted from flowers and form high concentrations in the air. They are associated with immediate reactivity on skin tests, bind to patient sera IgE, and might be relevant in allergic upper and lower airway diseases.

Mechanisms of light producing chemical reactions

An array of experimental and computational methods has been implement to elucidate the mechanisms of light producing chemical reactions that are important in nature and the laboratory.

More appraisal please : a commentary on Pfaff et al. (2007) 'Relations between mechanisms of CNS arousal and mechanisms of stress'

This article provides a brief commentary on Pfaff et al's timely review of the relations between mechanisms of CNS arousal and mechanisms of stress. Pfaff and colleagues use the review as a platform to propose the existence of a coherent stress-arousal state. We suggest that this proposal is, on a number of grounds, flawed. In turn, we counter that the while the states of stress and arousal are related they are as entities fundamentally separate. Moreover, we propose that any productive attempt to unite the two states must acknowledge the importance of and therefore centrally include higher order integrative phenomena, such as, appraisal.

Financial systems and mechanisms of growth in different conditions of country risk

This article uses panel data from 1976 to 2003 to investigate the ways in which banking and stock markets influence economic growth in situations of high and low country risk. The mean and Standard Deviation (SD) of country risk are adopted to classify 28 countries into Low Risk Low Volatility (LRLV) and High Risk High Volatility (HRHV) subgroups. Through the technique of error correction-based panel co-integration developed by Westerlund (2007), several results are obtained. First, LRLV countries can expand the capitalization of stock market to enhance long-term economic growth. Second, HRHV countries, on the other hand, use two distinct strategies to promote long-term economic growth. Initially they develop their equity markets, which promote economic growth directly. Strengthened equity markets, in turn, aid in the development of credit markets, which subsequently brings an economic boom. Finally, regardless of selected subgroups, the contribution of stock market capitalization to economic growth appears to be substantially larger than that of bank credit, highlighting the importance of stock markets.

The impact of strategy on business analytics success

Business analytics systems are an important strategic investment for many organisations and can potentially contribute significantly to firm performance. In this paper we develop a theoretical model, based on the resource-based view, that explains how business analytics capabilities lead to benefits. We argue that the type of strategy, represented as enterprise architecture, moderates the benefits achieved. Two case studies are then presented, each with a different type of strategy, and we explain how and why benefits were achieved from business analytics systems in each. We then identify the similarities and differences between the two case studies and discuss these using five dimensions that emerge from the case studies: strategic alignment, governance, people, organizational culture and data and technology infrastructure.