1,338 research outputs found

    Zero-configuration identity-based signcryption scheme for Smart Grid

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    The success of future intelligent power deliver and transmission systems across the globe relies critically on the availability of a fast, scalable, and most importantly secure communication infrastructure between the energy producers and consumers. One major obstacle to ensure secure communication among various parties in a smart grid network hinges on the technical and implementation difficulties associated with key distribution in such large-scale network with often-time disinterested consumers. This paper proposes the use of an identity-based signcryption (IBS) system to provide a zero-configuration encryption and authentication solution for end-to-end secure communications. The suitability of employing such identity-based cryptosystems in the context of smart grids is studied from the perspective of security requirements, implementation overhead and ease of management. Using the design and implementation experience of our proposed system as an example, we illustrate that IBS is a viable solution to providing a secure and easy-to-deploy solution with close to zero user setup required.published_or_final_versionThe 1st IEEE International Conference on Smart Grid Communications (SmartGridComm 2010), Gaithersburg, MD., 4-6 October 2010. In Proceedings of the 1st SmartGridComm, 2010, p. 321-32

    Zero-configuration identity-based IP network encryptor

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    For corporations or individuals who wish to protect the confidentiality of their data across computer networks, network-layer encryption offers an efficient and proven method for preserving data privacy. Network layer encryption such as IPSec is more flexible than higher layer solutions since it is not application-dependent and can protect all end-to-end traffics that go between two hosts. Using IPSec, two hosts must first establish a session key through message exchanges before they can communicate. In this paper, we present an Identity Based Encryption (IBE) scheme that allows a host to calculate the per-packet encryption key based on the IP address of the destination host, without going through the expensive key exchange process as in IPSec. Our mechanism is compatible with the current IP protocol and we tested our scheme with live HTTP and ICMP traffic. Our results show that our protocol provides a zero-configuration network layer encryption solution for end-to-end secure communications that is ideal for consumer electronics applications. © 2006 IEEE.published_or_final_versio

    Synergistic effect of nogo-neutralizing antibody IN-1 and ciliary neurotrophic factor on axonal regeneration in adult rodent visual systems

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    The presence of Nogo axon regeneration inhibitory molecules in the central nervous system (CNS) and the counteracting effect of IN-1 antibodies have been widely reported. In this study, we examined the effect of IN-1-producing hybridoma cells on axon regeneration in adult rodent retinal ganglion cells (RGCs) after various types of optic nerve (ON) injury, evaluating therein whether ciliary neurotrophic factor (CNTF) potentiated the effect of IN-1. We found that application of IN-1 alone failed to enhance regeneration of intracranially or intraorbitally transected RGC axons in a peripheral nerve (PN) graft. IN-1 hybridoma cells also failed to significantly promote intraorbitally crushed ON axons to reenter the distal part of the ON. However, a combined application of IN-1 and CNTF had a synergistic effect in both intracranial PN and intraorbital ON crush paradigms. This study suggests that the action of IN-1 antibodies in promoting axon regeneration in the CNS could be more effective when coupled with other appropriate factors.published_or_final_versio

    Vitamin B12 levels in patients with type 2 diabetes mellitus on metformin

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    Background: Due to the clinical benefits of metformin, its associated side effects such as vitamin B12 deficiency are usually overlooked and rarely investigated.Objective: This study was carried out to determine the serum level of vitamin B12 in Nigerian patients with type 2 diabetes mellitus (T2DM) on metformin.Methods: Serum vitamin B12 level was determined using high performance liquid chromatography (HPLC) in 81 T2DM patients who have been on metformin for 5 years or more. Vitamin B12 deficiency was defined as serum concentration of <200 pg/dl, borderline deficiency as 200 – 300 pg/dl and >300 pg/dl as normal. Differences in vitamin B12 levels between different groups were assessed using Mann Whitney U test and P<0.05 was considered as statistically significant.Results: Vitamin B12 deficiency and borderline deficiency were recorded in 8.6% and 26.0% of the patients respectively. Vitamin B12 level was significantly lower in patients who have been on metformin for  ≄10 years compared with patients with <10 years history of metformin use. Similarly, patients who were on metformin at a dose of >1000 mg/day had significantly lower vitamin B12 level when compared with patients on ≀1000 mg/day.Conclusion: Low serum vitamin B12 level is associated with longer duration and higher dose of metformin use. Therefore, routine determination of vitamin B12 level in patients with T2DM on high dose of metformin and those with prolonged use of metformin might help in identifying patients that would benefit from vitamin B12 supplements.Keywords: Metformin, Type 2 diabetes mellitus, Vitamin B12 deficienc

    Restoration of optic neuropathy

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    Optic neuropathy refers to disorders involving the optic nerve (ON). Any damage to ON or ON-deriving neurons, the retinal ganglion cells (RGCs), may lead to the breakdown of the optical signal transmission from the eye to the brain, thus resulting in a partial or complete vision loss. The causes of optic neuropathy include trauma, ischemia, inflammation, compression, infiltration, and mitochondrial damages. ON injuries include primary and secondary injuries. During these injury phases, various factors orchestrate injured axons to die back and become unable to regenerate, and these factors could be divided into two categories: extrinsic and intrinsic. Extrinsic inhibitory factors refer to the environmental conditions that influence the regeneration of injured axons. The presence of myelin inhibitors and glial scar, lack of neurotrophic factors, and inflammation mediated by injury are regarded as these extrinsic factors. Extrinsic factors need to trigger the intracellular signals to exert inhibitory effect. Proper regulation of these intracellular signals has been shown to be beneficial to ON regeneration. Intrinsic factors of RGCs are the pivotal reasons that inhibit ON regeneration and are closely linked with extrinsic factors. Intracellular cyclic adenosine monophosphate (cAMP) and calcium levels affect axon guidance and growth cone response to guidance molecules. Many genes, such as Bcl-2, PTEN, and mTOR, are crucial in cell proliferation, axon guidance, and growth during development, and play important roles in the regeneration and extension of RGC axons. With transgenic mice and related gene regulations, robust regeneration of RGC axons has been observed after ON injury in laboratories. Although various means of experimental treatments such as cell transplantation and gene therapy have achieved significant progress in neuronal survival, axonal regeneration, and restoration of the visual function after ON injury, many unresolved scientific problems still exist for their clinical applications. Therefore, we still need to overcome hurdles before developing effective therapy to treat optic neuropathy diseases in patients.published_or_final_versio

    Evaluation of the aqueous extract of Boswellia dalzielii stem bark for antimicrobial activities and gastrointestinal effects

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    The aqueous extract of Boswelli dalzielii Hutch (family: Burseraceae) was investigated for therapeutic properties using aspirin-induced ulceration in rats, gastrointestinal motility in mice and castor oil-induced diarrhoea in rats. The median lethal dose (LD50) of the extract was carried out via the oral route in mice. Antimicrobial and preliminary phytochemical screening of the extract was also investigated. The extract did not show toxicity signs or death at doses O.O5) protection against castor oil-induced diarrhoea in rats. No antimicrobial effects were shown by the extract (200 mg/kg) against any of the tested organisms. Tannins were detected in the aqueous extract. The above results show that B. dalzielii stem bark probably contains some active ingredients that could be developed for such gastrointestinal problems as have been claimed by traditional medical practitioners. Key words: . African Journal of Biotechnology Vol.3(5) 2004: 284-28

    Recent advances in noninvasive glucose monitoring

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    Author name used in this publication: Chi-Fuk SoAuthor name used in this publication: Joanne W. Y. Chung2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Occult alpha globin gene mutations are the commonest causes of red cell microcytosis unexplained by phenotypic testing

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    HAA: Haematology Society of Australia and New Zealand, The Australian & New Zealand Society of Blood Transfusion and The Australasian Society of Thrombosis and HaemostasisAIM: Hypochromic microcytic anaemia is the hallmark phenotype of thalassaemia. Current phenotypic tests do not provide a diagnosis in a small proportion of patients with red cell microcytosis. We investigated the genetic basis of microcytosis in a cohort of such subjects. METHOD: We identified from a large cohort of 1684 unselected requests for thalassaemia testing 25 Chinese subjects who had unexplained microcytosis after phenotypic haemoglobin studies. Extensive genotypic analysis of the α and ÎČ globin gene cluster was performed in 20 of these subjects who had adequate DNA. Techniques employed included gap-polymerase chain reaction, amplification-refractory mutation system, Sanger sequencing and multiplex ligation-dependent 
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    The molecular mechanism of the anti-oxidative effects of catechin on palmitic acid-induced cytotoxicity in astrocytes

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    Poster PresentationAIMS: Metabolic syndrome (MS) encompasses a group of problems which will put a person at a high risk of developing cardiovascular diseases, including heart attack and stroke. Effective prevention or treatment of MS significantly reduces the risk for developing serious complications. Palmitic acid (PA) is a saturated fatty acid, when being excessive, is a significant risk factor for development of MS or stroke. However, damage by MS to astrocytes is relatively unexplored. Catechin is an effective antioxidant which would be beneficial to neurons subjected to reactive oxygen species (ROS) damage as well ...postprin

    IL-4-secreting CD4+ T cells are crucial to the development of CD8+ T-cell responses against malaria liver stages.

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    CD4+ T cells are crucial to the development of CD8+ T cell responses against hepatocytes infected with malaria parasites. In the absence of CD4+ T cells, CD8+ T cells initiate a seemingly normal differentiation and proliferation during the first few days after immunization. However, this response fails to develop further and is reduced by more than 90%, compared to that observed in the presence of CD4+ T cells. We report here that interleukin-4 (IL-4) secreted by CD4+ T cells is essential to the full development of this CD8+ T cell response. This is the first demonstration that IL-4 is a mediator of CD4/CD8 cross-talk leading to the development of immunity against an infectious pathogen
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