2,668 research outputs found

    A New Analysis Method for Simulations Using Node Categorizations

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    Most research concerning the influence of network structure on phenomena taking place on the network focus on relationships between global statistics of the network structure and characteristic properties of those phenomena, even though local structure has a significant effect on the dynamics of some phenomena. In the present paper, we propose a new analysis method for phenomena on networks based on a categorization of nodes. First, local statistics such as the average path length and the clustering coefficient for a node are calculated and assigned to the respective node. Then, the nodes are categorized using the self-organizing map (SOM) algorithm. Characteristic properties of the phenomena of interest are visualized for each category of nodes. The validity of our method is demonstrated using the results of two simulation models. The proposed method is useful as a research tool to understand the behavior of networks, in particular, for the large-scale networks that existing visualization techniques cannot work well.Comment: 9 pages, 8 figures. This paper will be published in Social Network Analysis and Mining(www.springerlink.com

    The salivary gland transcriptome of the neotropical malaria vector Anopheles darlingi reveals accelerated evolution of genes relevant to hematophagy

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    BackgroundMosquito saliva, consisting of a mixture of dozens of proteins affecting vertebrate hemostasis and having sugar digestive and antimicrobial properties, helps both blood and sugar meal feeding. Culicine and anopheline mosquitoes diverged ~150 MYA, and within the anophelines, the New World species diverged from those of the Old World ~95 MYA. While the sialotranscriptome (from the Greek sialo, saliva) of several species of the Cellia subgenus of Anopheles has been described thoroughly, no detailed analysis of any New World anopheline has been done to date. Here we present and analyze data from a comprehensive salivary gland (SG) transcriptome of the neotropical malaria vector Anopheles darlingi (subgenus Nyssorhynchus).ResultsA total of 2,371 clones randomly selected from an adult female An. darlingi SG cDNA library were sequenced and used to assemble a database that yielded 966 clusters of related sequences, 739 of which were singletons. Primer extension experiments were performed in selected clones to further extend sequence coverage, allowing for the identification of 183 protein sequences, 114 of which code for putative secreted proteins.ConclusionComparative analysis of sialotranscriptomes of An. darlingi and An. gambiae reveals significant divergence of salivary proteins. On average, salivary proteins are only 53% identical, while housekeeping proteins are 86% identical between the two species. Furthermore, An. darlingi proteins were found that match culicine but not anopheline proteins, indicating loss or rapid evolution of these proteins in the old world Cellia subgenus. On the other hand, several well represented salivary protein families in old world anophelines are not expressed in An. darlingi

    Weather-it missions: a social network analysis perspective of an online citizen inquiry community

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    Citizen inquiry is an innovative informal science learning approach, which engages members of the general public in scientific investigations sparked by their personal experience of everyday science, and to which other members can contribute. This paper aims to describe the network of interactions and contributions of Weather-it, an online Citizen Inquiry community accommodated by the nQuire-it platform, which involves people in creating and maintaining their own weather missions (investigations). The interaction patterns within Weather-it are mainly explored through social network analysis of community members and missions. The results indicate the quiet and active members within the community, their splitting into sub-communities, and their contribution and data collection methods and preferences. These results provide in-sight into the behaviour of people in such public engagement projects

    An insight into the sialotranscriptome of the West Nile mosquito vector, <it>Culex tarsalis</it>

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    <p>Abstract</p> <p>Background</p> <p>Saliva of adult female mosquitoes help sugar and blood feeding by providing enzymes and polypeptides that help sugar digestion, control microbial growth and counteract their vertebrate host hemostasis and inflammation. Mosquito saliva also potentiates the transmission of vector borne pathogens, including arboviruses. <it>Culex tarsalis </it>is a bird feeding mosquito vector of West Nile Virus closely related to <it>C. quinquefasciatus</it>, a mosquito relatively recently adapted to feed on humans, and the only mosquito of the genus <it>Culex </it>to have its sialotranscriptome so far described.</p> <p>Results</p> <p>A total of 1,753 clones randomly selected from an adult female <it>C. tarsalis </it>salivary glands (SG) cDNA library were sequenced and used to assemble a database that yielded 809 clusters of related sequences, 675 of which were singletons. Primer extension experiments were performed in selected clones to further extend sequence coverage, allowing for the identification of 283 protein sequences, 80 of which code for putative secreted proteins.</p> <p>Conclusion</p> <p>Comparison of the <it>C. tarsalis </it>sialotranscriptome with that of <it>C. quinquefasciatus </it>reveals accelerated evolution of salivary proteins as compared to housekeeping proteins. The average amino acid identity among salivary proteins is 70.1%, while that for housekeeping proteins is 91.2% (P < 0.05), and the codon volatility of secreted proteins is significantly higher than those of housekeeping proteins. Several protein families previously found exclusive of mosquitoes, including only in the <it>Aedes </it>genus have been identified in <it>C. tarsalis</it>. Interestingly, a protein family so far unique to <it>C. quinquefasciatus</it>, with 30 genes, is also found in <it>C. tarsalis</it>, indicating it was not a specific <it>C. quinquefasciatus </it>acquisition in its evolution to optimize mammal blood feeding.</p

    An insight into the sialome of the oriental rat flea, Xenopsylla cheopis (Rots)

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    <p>Abstract</p> <p>Background</p> <p>The salivary glands of hematophagous animals contain a complex cocktail that interferes with the host hemostasis and inflammation pathways, thus increasing feeding success. Fleas represent a relatively recent group of insects that evolved hematophagy independently of other insect orders.</p> <p>Results</p> <p>Analysis of the salivary transcriptome of the flea <it>Xenopsylla cheopis</it>, the vector of human plague, indicates that gene duplication events have led to a large expansion of a family of acidic phosphatases that are probably inactive, and to the expansion of the FS family of peptides that are unique to fleas. Several other unique polypeptides were also uncovered. Additionally, an apyrase-coding transcript of the CD39 family appears as the candidate for the salivary nucleotide hydrolysing activity in <it>X.cheopis</it>, the first time this family of proteins is found in any arthropod salivary transcriptome.</p> <p>Conclusion</p> <p>Analysis of the salivary transcriptome of the flea <it>X. cheopis </it>revealed the unique pathways taken in the evolution of the salivary cocktail of fleas. Gene duplication events appear as an important driving force in the creation of salivary cocktails of blood feeding arthropods, as was observed with ticks and mosquitoes. Only five other flea salivary sequences exist at this time at NCBI, all from the cat flea <it>C. felis</it>. This work accordingly represents the only relatively extensive sialome description of any flea species. Sialotranscriptomes of additional flea genera will reveal the extent that these novel polypeptide families are common throughout the Siphonaptera.</p

    PET imaging of brain inflammation during early epileptogenesis in a rat model of temporal lobe epilepsy.

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    Background Recently, inflammatory cascades have been suggested as a target for epilepsy therapy. Positron emission tomography (PET) imaging offers the unique possibility to evaluate brain inflammation longitudinally in a non-invasive translational manner. This study investigated brain inflammation during early epileptogenesis in the post-kainic acid-induced status epilepticus (KASE) model with post-mortem histology and in vivo with [18F]-PBR111 PET. Methods Status epilepticus (SE) was induced (N = 13) by low-dose injections of KA, while controls (N = 9) received saline. Translocator protein (TSPO) expression and microglia activation were assessed with [125I]-CLINDE autoradiography and OX-42 immunohistochemistry, respectively, 7 days post-SE. In a subgroup of rats, [18F]-PBR111 PET imaging with metabolite-corrected input function was performed before post-mortem evaluation. [18F]-PBR111 volume of distribution (V t) in volume of interests (VOIs) was quantified by means of kinetic modelling and a VOI/metabolite-corrected plasma activity ratio. Results Animals with substantial SE showed huge overexpression of TSPO in vitro in relevant brain regions such as the hippocampus and amygdala (P < 0.001), while animals with mild symptoms displayed a smaller increase in TSPO in amygdala only (P < 0.001). TSPO expression was associated with OX-42 signal but without obvious cell loss. Similar in vivo [18F]-PBR111 increases in V t and the simplified ratio were found in key regions such as the hippocampus (P < 0.05) and amygdala (P < 0.01). Conclusion Both post-mortem and in vivo methods substantiate that the brain regions important in seizure generation display significant brain inflammation during epileptogenesis in the KASE model. This work enables future longitudinal investigation of the role of brain inflammation during epileptogenesis and evaluation of anti-inflammatory treatments. © 2012, Springer

    Cancer mortality in East and Southeast Asian migrants to New South Wales, Australia, 1975–1995

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    Routinely collected data for New South Wales were used to analyse cancer mortality in migrants born in East or Southeast Asia according to duration of residence in Australia. A case-control approach compared deaths from cancer at particular sites with deaths from all other cancers, adjusting for age, sex and calendar period. Compared with the Australian-born, these Asian migrants had a 30-fold higher risk of dying from nasopharyngeal cancer in the first 2 decades of residence, falling to ninefold after 30 years, and for deaths from liver cancer, a 12-fold risk in the first 2 decades, falling to threefold after 30 years. The initial lower risk from colorectal, breast or prostate cancers later converged towards the Australian-born level, the change being apparent in the third decade after migration. The relative risk of dying from lung cancer among these Asian migrants was above unity for each category of duration of stay for women, but at or below unity for men, with no trend in risk over time. An environmental or lifestyle influence for nasopharyngeal and liver cancers is suggested as well as for cancers of colon/rectum, breast and prostate. © 1999 Cancer Research Campaig

    Stabilization of angiotensin-(1-7) by key substitution with a cyclic non-natural amino acid

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    Angiotensin-(1-7) [Ang-(1-7)], a heptapeptide hormone of the renin-angiotensin-aldosterone system (RAAS), is a promising candidate as a treatment for cancer that reflects its antiproliferative and anti-angiogenic properties. However, the peptide’s therapeutic potential is limited by the short half-life and low bioavailability resulting from rapid enzymatic metabolism by peptidases including angiotensin-converting enzyme (ACE) and dipeptidyl peptidase 3 (DPP 3). We report the facile assembly of three novel Ang-(1-7) analogues by solid-phase peptide synthesis which incorporates the cyclic non-natural δ-amino acid ACCA. The analogues containing the ACCA substitution at the site of ACE cleavage exhibit complete resistance to human ACE, while substitution at the DDP3 cleavage site provided stability against DPP 3 hydrolysis. Furthermore, the analogues retain the anti-proliferative properties of Ang-(1-7) against the 4T1 and HT-1080 cancer cell lines. These results suggest that ACCA-substituted Ang-(1-7) analogues which show resistance against proteolytic degradation by peptidases known to hydrolyze the native heptapeptide may be novel therapeutics in the treatment of cancer

    Buprenorphine-Naloxone in the Treatment of Codeine Dependence: a Scoping Review of Clinical Case Presentations

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    Misuse of prescribed and over the counter (OTC) codeine containing medicines is an increasing public health concern in recent times. Studies have called for low threshold treatment services for individuals experiencing codeine dependence using buprenorphine naloxone therapy. We present a scoping review of clinical case presentation literature on the use of buprenorphine-naloxone in the treatment of codeine dependence. Seven records (four single case studies and three case series) on codeine dependence treated with buprenorphine-naloxone were included. Five themes emerged following a review of the cases for the treatment of codeine dependence with buprenorphine-naloxone. They are: (1) Patient Profiles; (2) History of Codeine Misuse; (3) Medical Problems; (4) Use of Other Substances; and (5) Buprenorphine-naloxone in the treatment of Codeine Dependence. The review highlights the complexities of patients with regards to pain, psychiatric illness, poly substance use and iatrogenic dependence, with findings encouraging in terms of patient stabilisation and recovery

    Quantum Criticality in Heavy Fermion Metals

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    Quantum criticality describes the collective fluctuations of matter undergoing a second-order phase transition at zero temperature. Heavy fermion metals have in recent years emerged as prototypical systems to study quantum critical points. There have been considerable efforts, both experimental and theoretical, which use these magnetic systems to address problems that are central to the broad understanding of strongly correlated quantum matter. Here, we summarize some of the basic issues, including i) the extent to which the quantum criticality in heavy fermion metals goes beyond the standard theory of order-parameter fluctuations, ii) the nature of the Kondo effect in the quantum critical regime, iii) the non-Fermi liquid phenomena that accompany quantum criticality, and iv) the interplay between quantum criticality and unconventional superconductivity.Comment: (v2) 39 pages, 8 figures; shortened per the editorial mandate; to appear in Nature Physics. (v1) 43 pages, 8 figures; Non-technical review article, intended for general readers; the discussion part contains more specialized topic
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