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Mahajan S.G.,Massachusetts Institute of Technology | Abrahamson J.T.,Massachusetts Institute of Technology | Abrahamson J.T.,University of Minnesota | Birkhimer S.,Massachusetts Institute of Technology | And 5 more authors.
Energy and Environmental Science | Year: 2014

Spatially propagating reaction waves are central to a variety of energy applications, such as high temperature solid phase or combustion synthesis, and thermopower waves. In this paper, we identify and study a previously unreported property of such waves, specifically that they can generate temperatures far in excess of the adiabatic limit. We show that this superadiabaticity occurs when a reaction wave in either one dimension (1D) or two dimensions (2D) impinges upon an adiabatic boundary under specific reaction and heat transfer conditions. This property is studied analytically and computationally for a series of 1D and 2D example systems, producing an estimate of the upper bound for excess temperature rise as high as 1.8 times the adiabatic limit, translating to temperatures approaching 2000 K for some practical materials. We show that superadiabaticity may enable several new types of energy conversion mechanisms, including thermophotovoltaic wave harvesting, which we analyze for efficiency and power density. © The Royal Society of Chemistry 2014. Source


Low M.,University of Western Sydney | Khoo C.S.,University of Western Sydney | Munch G.,University of Western Sydney | Govindaraghavan S.,Meridian | Sucher N.J.,Roxbury Community College
BMC Complementary and Alternative Medicine | Year: 2015

Background: The anti-inflammatory activity of Andrographis paniculata (Acanthaceae), a traditional medicine widely used in Asia, is commonly attributed to andrographolide, its main secondary metabolite. Commercial A. paniculata extracts are standardised to andrographolide content. We undertook the present study to investigate 1) how selective enrichment of andrographolide in commercial A. paniculata extracts affects the variability of non-standardised phytochemical components and 2) if variability in the non-standardised components of the extract affects the pharmacological activity of andrographolide itself. Methods: We characterized 12 commercial, standardised (≥30% andrographolide) batches of A. paniculata extracts from India by HPLC profiling. We determined the antioxidant capacity of the extracts using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, oxygen radical antioxidant capacity (ORAC) and a Folin-Ciocalteu (FC) antioxidant assays. Their anti-inflammatory activity was assessed by assaying their inhibitory effect on the release of tumor necrosis factor alpha (TNF-α) in the human monocytic cell line THP-1. Results: The andrographolide content in the samples was close to the claimed value (32.2±2.1%, range 27.5 to 35.9%). Twenty-one non-standardised constituents exhibited more than 2-fold variation in HPLC peak intensities in the tested batches. The chlorogenic acid content of the batches varied more than 30-fold. The DPPH free radical scavenging activity varied ~3-fold, the ORAC and FC antioxidant capacity varied ~1.5 fold among batches. In contrast, the TNF-α inhibitory activity of the extracts exhibited little variation and comparison with pure andrographolide indicated that it was mostly due to their andrographolide content. Conclusions: Standardised A. paniculata extracts contained the claimed amount of andrographolide but exhibited considerable phytochemical background variation. DPPH radical scavenging activity of the extracts was mostly due to the flavonoid/phenlycarboxylic acid compounds in the extracts. The inhibitory effect of andrographolide on the release of TNF-α was little affected by the quantitative variation of the non-standardised constituents. © 2015 Low et al. Source


Gunawardena D.,University of Western Sydney | Karunaweera N.,University of Western Sydney | Lee S.,University of Western Sydney | Van Der Kooy F.,University of Western Sydney | And 6 more authors.
Food and Function | Year: 2015

Chronic inflammation is a contributing factor in many age-related diseases. In a previous study, we have shown that Sri Lankan cinnamon (C. zeylanicum) was one of the most potent anti-inflammatory foods out of 115 foods tested. However, knowledge about the exact nature of the anti-inflammatory compounds and their distribution in the two major cinnamon species used for human consumption is limited. The aim of this investigation was to determine the anti-inflammatory activity of C. zeylanicum and C. cassia and elucidate their main phytochemical compounds. When extracts were tested in LPS and IFN-γ activated RAW 264.7 macrophages, most of the anti-inflammatory activity, measured by down-regulation of nitric oxide and TNF-α production, was observed in the organic extracts. The most abundant compounds in these extracts were E-cinnamaldehyde and o-methoxycinnamaldehyde. The highest concentration of E-cinnamaldehyde was found in the DCM extract of C. zeylanicum or C. cassia (31 and 34 mg g-1 of cinnamon, respectively). When these and other constituents were tested for their anti-inflammatory activity in RAW 264.7 and J774A.1 macrophages, the most potent compounds were E-cinnamaldehyde and o-methoxycinnamaldehyde, which exhibited IC50 values for NO with RAW 264.7 cells of 55 ± 9 μM (7.3 ± 1.2 μg mL-1) and 35 ± 9 μM (5.7 ± 1.5 μg mL-1), respectively; and IC50 values for TNF-α of 63 ± 9 μM (8.3 ± 1.2 μg mL-1) and 78 ± 16 μM (12.6 ± 2.6 μg mL-1), respectively. If therapeutic concentrations can be achieved in target tissues, cinnamon and its components may be useful in the treatment of age-related inflammatory conditions. This journal is © The Royal Society of Chemistry 2015. Source


Shen B.,University of Western Sydney | Truong J.,University of Western Sydney | Helliwell R.,University of Western Sydney | Govindaraghavan S.,Lipa Pharmaceuticals | And 3 more authors.
BMC Complementary and Alternative Medicine | Year: 2013

Background: Age is the leading risk factor for acute and chronic neurodegenerative diseases. The Shen Nong Ben Cao Jing, the oldest known compendium of Chinese materia media, lists herbal medicines that were believed to exert neither fast acting pharmacological effects nor discernible toxicity, but to promote general health and longevity. In modern terms, these herbal medicines could be considered as complementary health care products for prevention rather than treatment of diseases. In the present study, we examined whether a selection of 13 such herbal medicines exhibited neuroprotective activity.Methods: The antioxidant capacity of the herbal extracts was determined using three non-cellular assays measuring the total phenol content (FCR assay), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity and oxygen radical absorbance capacity (ORAC). Cytotoxic effects of the herbal extracts were assayed in cultured mouse cortical neurons and their neuroprotective activities were studied using staurosporine-induced apoptosis of the cultured neurons.Results: Most of the herbal extracts showed negligible toxic effects at 100 μg/ml. However, Polygonum multiflorum and Rhodiola rosea exhibited some neurotoxicity at this concentration. Extracts of Ganoderma lucidum, Glycyrrhiza glabra, Schizandra chinensis, and Polygonum cuspidatum inhibited staurosporine-induced apoptosis by 30 - 50% in a dose-dependent manner. The neuroprotective effects of Polygonum cuspidatum were predominantly due to its major ingredient, resveratrol. The effective herbal extracts showed various levels of reactive oxygen species (ROS) scavenging capacity, which was significantly correlated with their neuro- protective activity. However, P. multiflorum and R. rosea extracts proved to be the exception as they exhibited a high level of antioxidant capacity, but did not exhibit neuroprotective effects in cell-based assay.Conclusions: This in vitro study provides evidence for neuroprotective activity of some Chinese herbal medicines traditionally used to promote healthy ageing and longevity. Our results provide a justification for further study of these herbal extracts in neurodegenerative animal models to assess their safety and effectiveness as a basis for subsequent clinical trials. These herbal medicines might potentially offer a novel preemptive neuroprotective approach in neurodegenerative diseases and might be developed for use in persons at risk. © 2013 Shen et al.; licensee BioMed Central Ltd. Source


Sucher N.J.,Roxbury Community College | Sucher N.J.,Northern Essex Community College
Synergy | Year: 2014

In this paper, I examine the role of the idea of synergy in life science research using examples in the fields of pharmacology/toxicology, molecular genetics and development, biochemistry, ecology and metabolic engineering. The research shows that synergy exhibits scale invariance. Small molecules act synergistically in the activation of single receptor molecules. Proteins function synergistically in development, metabolism and signaling. Synergy was found in the interaction between communities of organisms. Synergy manifests itself quantitatively or qualitatively: synergistic effects can be smaller or larger or they can be entirely different from what was expected. There is no single mathematical model that can be used uniformly to detect and quantify synergy. Synergy provides benefits for human health, wellbeing and economy. Synergy has explanatory and heuristic value in our quest to understand the function of and in designing complex biological systems. © 2014 Elsevier GmbH. Source

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