372 research outputs found

    Image Search Reranking with click based similarity using Color Features Algorithm

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    In image search re-ranking, besides the well-known semantic gap, intent gap, which is the gap between the representation of users? query/demand and the real intent of the users, is becoming a major problem restricting the development of image retrieval. To reduce human effects, in this paper, we use image click-through data, which can be viewed as the implicit feedback from users, to help overcome the intention gap, and further improve the image search performance. Generally, the hypothesis visually similar images should be close in a ranking list and the strategy images with higher relevance should be ranked higher than others are widely accepted. To obtain satisfying search results, thus, image similarity and the level of relevance typicality are determinate factors correspondingly. Then, based on the learnt click-based image similarity measure, we conduct spectral clustering to group visually and semantically similar images into same clusters, and get the final re-ranklist by calculating click-based clusters typicality and within clusters click-based image typicality in descending order. Our experiments conducted on two real-world query-image data sets with diverse representative queries show that our proposed re-ranking approach can significantly improve initial search results, and outperform several existing re-ranking approaches

    Evidence of co-infection of chikungunya and densonucleosis viruses in C6/36 cell lines and laboratory infected Aedes aegypti (L.) mosquitoes

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    <p>Abstract</p> <p>Background</p> <p>Densonucleosis viruses are the etiological agents of insect's disease. We have reported the isolation of densovirus from India and its distribution among the natural populations of <it>Aedes aegypti </it>mosquitoes across the country. Since densonucleosis virus persistently infects mosquito populations, and is demonstrated to negatively affect multiplication of dengue virus in <it>Aedes albopictus</it>, it would be interesting to study if this virus has a role in determining the susceptibility of the vector mosquito <it>Ae. aegypti </it>to chikugunya virus.</p> <p>Methods</p> <p>Mosquito cell lines and adult <it>Ae. aegypti </it>mosquitoes infected with densovirus were superinfected with Chikungunya virus and both the viruses were quantitated by determining their genomic copy number by real time amplification. Comparison was made between the log of genomic copy numbers of the viruses in the presence and absence of each other.</p> <p>Results</p> <p>The log of copy number of the viruses did not vary due to co-infection. Even though the RNA copy number of chikungunya virus increased over the period of time, no change was observed in the RNA copy number between the control and the co-infected group on any given day. Similarly, DNA copy number of densovirus also remained unchanged between the control and the co-infected groups.</p> <p>Conclusion</p> <p>Chikungunya virus neither stimulates the replication of densovirus nor is its own replication suppressed due to co-infection. <it>Ae. aegypti </it>mosquitoes with densovirus infection were as susceptible to infection by chikungunya virus as the uninfected mosquitoes.</p

    Avian Influenza H9N2 Seroprevalence among Poultry Workers in Pune, India, 2010

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    Avian influenza (AI) H9N2 has been reported from poultry in India. A seroepidemiological study was undertaken among poultry workers to understand the prevalence of antibodies against AI H9N2 in Pune, Maharashtra, India. A total of 338 poultry workers were sampled. Serum samples were tested for presence of antibodies against AI H9N2 virus by hemagglutination inhibition (HI) and microneutralization (MN) assays. A total of 249 baseline sera from general population from Pune were tested for antibodies against AI H9N2 and were negative by HI assay using ≄40 cut-off antibody titre. Overall 21 subjects (21/338 = 6.2%) were positive for antibodies against AI H9N2 by either HI or MN assays using ≄40 cut-off antibody titre. A total of 4.7% and 3.8% poultry workers were positive for antibodies against AI H9N2 by HI and MN assay respectively using 40 as cut-off antibody titre. This is the first report of seroprevalence of antibodies against AI H9N2 among poultry workers in India

    Distribution and abundance of freshwater snails in Warwade Dam, Dutse, Northern Nigeria

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    Preliminary investigation in August, 2017 reported the presence of Lymnaea natalensis, Bellamya unicolor, Melanoides tuberculata and Bulinus globosus in order of increasing abundance and distribution in Warwade dam, Dutse, Jigawa State, Nigeria. A follow up study was carried out from April to October, 2019 to reveal further details on the abundance and distribution of freshwater snails in relation to some physiochemical factors of the dam. Four sampling sites; human activity, vegetation cover, lentic and lotic were selected for the study along the bank of the dam. Freshwater snails were collected using long handled scoop net with mesh 0.2mm complemented by hand picking methods in the four sampling sites. Water samples from the sampling sites were analyzed in the laboratory using standard procedures. A total of 2,027 of freshwater snails belonging to ten species were identified. Bulinus globosus 12(0.6%) and Lymnaea natalensis 12(0.6%) had the lowest abundance and distribution while Melanoides tuberculata 1553(76.6%) had the highest. Snail abundance was highest in site characterized by human activities (670) followed by vegetation (482), lotic (442) and lentic (433) waters. Most of the physico-chemical factors measured appeared to favour the growth and survival of fresh water snails. pH (p = 0.01), water current (p = &lt;0.01) and magnesium ion concentration (p = &lt; 0.01) varied significantly across the four sites. Only calcium ion concentration was significantly associated with snail abundance (p = 0.04). Snail abundance showed weak positive relationship with water temperature, color, turbidity and concentration of magnesium ion. The dam habours about ten species of freshwater snails in different abundance and distribution with M. tuberculata being the most abundant throughout the period of investigation. The dominance of M. tuberculata over other species particularly those of medical and veterinary importance could have positive implication for their control in the dam

    Preliminarna istraĆŸivanja polimorfizma hemoglobina i povezanosti s morfometrijskim svojstvima zapadnoafričkih patuljastih koza u sjevernom dijelu srediĆĄnje Nigerije

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    The aim of this study was to characterize the genetic pool of the West African Dwarf (WAD) goats using haemoglobin (Hb) polymorphism, as well as the association of some morphological traits with the Hb variants. Blood samples were collected from a total of 104 mature goats of both sexes belonging to the WAD breed in north central Nigeria. The red cell lysates were subjected to cellulose acetate electrophoresis and specific staining procedure to reveal the band patterns of haemoglobin. Three co-dominant alleles, causing the presence of three genotypes (AA, AB and AC) were detected among individual goats. The frequencies of the A, B and C alleles were 0.69, 0.30 and 0.01, respectively. The corresponding genotype frequencies for AA, AB and AC in the goat population were 0.37, 0.61 and 0.02, respectively. The discrepancy between the observed and the expected genotype number was significant (P0.05) by Hb variants. There is a need for further study encompassing more number of goats covering larger areas, use of DNA markers and their relationship with economic traits as well as performance study for detailed understanding of breed characteristics, conservation and genetic improvement of WAD goats in north central Nigeria.Cilj ovog istraĆŸivanja bila je genetska karakterizacija zapadnoafričkih patuljastih koza (WAD) pomoću polimorfizma hemoglobina (Hb), kao i povezanost nekih morfoloĆĄkih obiljeĆŸja s HB varijantama. Uzorci krvi spolno zrelih koza WAD pasmine (n=104) prikupljeni su u sjevernom dijelu srediĆĄnje Nigerije. Uzorci su uzeti od oba spola. Za utvrđivanje profila hemoglobina provedena je elektroforeza (celuloza acetat) i specifična tehnika bojanja gela. Tri kodominantna alela koja su uvjetovala prisutnost tri genotipa (AA, AB i AC) utvrđena su između pojedinih koza. Frekvencije alela A, B i C bile su 0,69, 0,30 i 0,01. Frekvencija genotipova AA bila je 0,37, AB 0,61 i AC 0,02. Nesukladnost između promatranog i očekivanog broja genotipova bila je značajna (P0,05) na ostale parametre tijela. Postoji potreba za daljnje istraĆŸivanje koje će obuhvatiti veći broj koza koje pokrivaju veća područja, koriĆĄtenjem DNA markera i njihova odnosa s gospodarskim svojstvima, kao i performans studije za razumijevanje svojstava pasmine, te očuvanje i genetsko unapređenje WAD pasmine koza u sjevernom dijelu srediĆĄnje Nigerije

    New perspectives in human stem cell therapeutic research

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    Human stem cells are in evaluation in clinical stem cell trials, primarily as autologous bone marrow studies, autologous and allogenic mesenchymal stem cell trials, and some allogenic neural stem cell transplantation projects. Safety and efficacy are being addressed for a number of disease state applications. There is considerable data supporting safety of bone marrow and mesenchymal stem cell transplants but the efficacy data are variable and of mixed benefit. Mechanisms of action of many of these cells are unknown and this raises the concern of unpredictable results in the future. Nevertheless there is considerable optimism that immune suppression and anti-inflammatory properties of mesenchymal stem cells will be of benefit for many conditions such as graft versus host disease, solid organ transplants and pulmonary fibrosis. Where bone marrow and mesenchymal stem cells are being studied for heart disease, stroke and other neurodegenerative disorders, again progress is mixed and mostly without significant benefit. However, correction of multiple sclerosis, at least in the short term is encouraging. Clinical trials on the use of embryonic stem cell derivatives for spinal injury and macular degeneration are beginning and a raft of other clinical trials can be expected soon, for example, the use of neural stem cells for killing inoperable glioma and embryonic stem cells for regenerating ÎČ islet cells for diabetes. The change in attitude to embryonic stem cell research with the incoming Obama administration heralds a new co-operative environment for study and evaluation of stem cell therapies. The Californian stem cell initiative (California Institute for Regenerative Medicine) has engendered global collaboration for this new medicine that will now also be supported by the US Federal Government. The active participation of governments, academia, biotechnology, pharmaceutical companies, and private investment is a powerful consortium for advances in health

    Development of an All-in-One Lentiviral Vector System Based on the Original TetR for the Easy Generation of Tet-ON Cell Lines

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    Lentiviral vectors (LVs) are considered one of the most promising vehicles to efficiently deliver genetic information for basic research and gene therapy approaches. Combining LVs with drug-inducible expression systems should allow tight control of transgene expression with minimal side effect on relevant target cells. A new doxycycline-regulated system based on the original TetR repressor was developed in 1998 as an alternative to the TetR-VP16 chimeras (tTA and rtTA) to avoid secondary effects due to the expression of transactivator domains. However, previously described TetR-based systems required cell cloning and/or antibiotic selection of tetracycline-responsive cells in order to achieve good regulation. In the present manuscript we have constructed a dual Tet-ON system based on two lentiviral vectors, one expressing the TetR through the spleen focus forming virus (SFFV) promoter (STetR) and a second expressing eGFP through the regulatable CMV-TetO promoter (CTetOE). Using these vectors we have demonstrated that the TetR repressor, contrary to the reverse transactivator (rtTA), can be expressed in excess to bind and modulate a high number of TetO operons. We have also showed that this dual vector system can generate regulatable bulk cell lines (expressing high levels of TetR) that are able to modulate transgene expression either by varying doxycycline concentration and/or by varying the amount of CTetOE vector genomes per cell. Based on these results we have developed a new all-in-one lentiviral vector (CEST) driving the expression of TetR through the SFFV promoter and the expression of eGFP through the doxycycline-responsive CMV-TetO operon. This vector efficiently produced Tet-ON regulatable immortalized (293T) and primary (human mesenchymal stem cells and human primary fibroblasts) cells. Bulk doxycycline-responsive cell lines express high levels of the transgene with low amount of doxycycline and are phenotypically indistinct from its parental cells

    Magnesia-Based Cements: A Journey of 150 Years, and Cements for the Future?

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    This review examines the detailed chemical insights that have been generated through 150 years of work worldwide on magnesium-based inorganic cements, with a focus on both scientific and patent literature. Magnesium carbonate, phosphate, silicate-hydrate, and oxysalt (both chloride and sulfate) cements are all assessed. Many such cements are ideally suited to specialist applications in precast construction, road repair, and other fields including nuclear waste immobilization. The majority of MgO-based cements are more costly to produce than Portland cement because of the relatively high cost of reactive sources of MgO and do not have a sufficiently high internal pH to passivate mild steel reinforcing bars. This precludes MgO-based cements from providing a large-scale replacement for Portland cement in the production of steel-reinforced concretes for civil engineering applications, despite the potential for CO2 emissions reductions offered by some such systems. Nonetheless, in uses that do not require steel reinforcement, and in locations where the MgO can be sourced at a competitive price, a detailed understanding of these systems enables their specification, design, and selection as advanced engineering materials with a strongly defined chemical basis
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